Skip to main content
NCBI home page
Antimicrobial Agents and Chemotherapy logoLink to Antimicrobial Agents and Chemotherapy
. 2016 Jan 29;60(2):1067–1078. doi: 10.1128/AAC.02379-15

Multiyear, Multinational Survey of the Incidence and Global Distribution of Metallo-β-Lactamase-Producing Enterobacteriaceae and Pseudomonas aeruginosa

Krystyna M Kazmierczak a,✉, Sharon Rabine a, Meredith Hackel a, Robert E McLaughlin b, Douglas J Biedenbach a, Samuel K Bouchillon a, Daniel F Sahm a, Patricia A Bradford b
PMCID: PMC4750703  PMID: 26643349

Abstract

Metallo-β-lactamases (MBLs) hydrolyze all classes of β-lactams except monobactams and are not inhibited by classic serine β-lactamase inhibitors. Gram-negative pathogens isolated from patient infections were collected from 202 medical centers in 40 countries as part of a global surveillance study from 2012 to 2014. Carbapenem-nonsusceptible Enterobacteriaceae and Pseudomonas aeruginosa were characterized for bla genes encoding VIM, IMP, NDM, SPM, and GIM variants using PCR and sequencing. A total of 471 MBL-positive isolates included the following species (numbers of isolates are in parentheses): P. aeruginosa (308), Klebsiella spp. (85), Enterobacter spp. (39), Proteeae (16), Citrobacter freundii (12), Escherichia coli (6), and Serratia marcescens (5) and were submitted by sites from 34 countries. Of these, 69.6% were collected in 9 countries (numbers of isolates are in parentheses): Russia (72), Greece (61), Philippines (54), Venezuela (29), and Kuwait, Nigeria, Romania, South Africa, and Thailand (20 to 25 isolates each). Thirty-two different MBL variants were detected (14 VIM, 14 IMP, and 4 NDM enzymes). Seven novel MBL variants were encountered in the study, each differing from a previously reported variant by one amino acid substitution: VIM-42 (VIM-1 [V223I]), VIM-43 (VIM-4 [A24V]), VIM-44 (VIM-2 [K257N]), VIM-45 (VIM-2 [T35I]), IMP-48 (IMP-14 [I69T]), IMP-49 (IMP-18 [V49F]), and NDM-16 (NDM-1 [R264H]). The in vitro activities of all tested antibiotics against MBL-positive Enterobacteriaceae were significantly reduced with the exception of that of aztreonam-avibactam (MIC90, 0.5 to 1 μg/ml), whereas colistin was the most effective agent against MBL-positive P. aeruginosa isolates (>97% susceptible). Although the global percentage of isolates encoding MBLs remains relatively low, their detection in 12 species, 34 countries, and all regions participating in this surveillance study is concerning.

INTRODUCTION

The worldwide dissemination of Gram-negative bacteria producing extended-spectrum β-lactamases (ESBLs) in the late 20th century resulted in a dearth of treatment options and an increase in the therapeutic use of carbapenems (1, 2). In turn, reports of carbapenem-resistant and carbapenemase-producing bacteria became more frequent (3–5). One important group of carbapenemases of special concern is the metallo-β-lactamases (MBLs). These enzymes belong to Ambler class B and require 1 or 2 zinc ions for enzyme activity (6). Many MBLs are chromosomally encoded in environmental bacteria or species that can act as opportunistic pathogens. However, a number of MBLs, including the NDM-type, IMP-type, and VIM-type MBLs, are plasmid encoded and readily transferable among clinically significant bacterial species, including Klebsiella pneumoniae and Escherichia coli (3). Notably, MBLs are often coproduced with Ambler class A and C serine β-lactamases, including ESBLs and AmpC enzymes (7).

MBLs hydrolyze all β-lactams except monobactams, including aztreonam, and are not inhibited by any of the commercially available β-lactamase inhibitors. Although aztreonam is active against many Gram-negative bacteria, it is inactive against isolates that produce ESBLs, KPC carbapenemases, or plasmid-encoded or stably derepressed, chromosomally encoded AmpC β-lactamases, thereby limiting its potential utility against MBL-producing isolates that also contain one or more of these serine β-lactamases (8). Avibactam is a non-β-lactam β-lactamase inhibitor that is active against Ambler class A and C and some class D (OXA-48) enzymes (9, 10). Aztreonam combined with avibactam has demonstrated activity against Enterobacteriaceae that coproduce MBLs and class A or class C β-lactamases (11, 12).

As part of a global surveillance program, the molecular basis of carbapenem resistance in Gram-negative pathogens was investigated in order to determine the incidence of acquired MBLs and the geographic regions in which these β-lactamases are most problematic. This report describes the isolation and regional distribution of MBL-positive Enterobacteriaceae and Pseudomonas aeruginosa isolates collected from 2012 to 2014.

MATERIALS AND METHODS

Nonduplicate bacterial isolates from intra-abdominal, urinary tract, skin and soft tissue, lower respiratory tract, and bloodstream infections were collected from 202 sites in 40 countries located in five major geographic regions (Asia-Pacific, Europe, Latin America, the Middle East-Africa, and North America). A predefined number of isolates of selected bacterial species were collected from each site regardless of antibiotic susceptibility. Organism collection, transport, confirmation of organism identification, susceptibility testing, molecular characterization, quality assurance of data, and development and management of a centralized database were coordinated by a central laboratory.

The organism identification of all isolates was confirmed using matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) mass spectrometry (Bruker Daltronics, Bremen, Germany). MICs were determined using frozen broth microdilution panels. Aztreonam-avibactam was tested with avibactam at a constant concentration of 4 μg/ml. Panel manufacture, inoculation, incubation, and interpretation were performed according to Clinical and Laboratory Standards Institute (CLSI) guidelines (13, 14). Using CLSI breakpoints, all Enterobacteriaceae and P. aeruginosa isolates that were nonsusceptible to any of the carbapenems tested (meropenem, imipenem, and doripenem) were molecularly characterized for β-lactamase (bla) genes encoding MBLs (IMP-, VIM-, NDM-, SPM-type enzymes) and serine β-lactamases (OXA-48-like and KPC-, TEM-, SHV-, CTX-M-, VEB-, PER-, GES-, ACT-, CMY-, DHA-, ACC-, MIR-, MOX-, and FOX-type enzymes) using a combination of the Check-MDR CT101 microarray (Check-Points B.V., Wageningen, the Netherlands) and multiplex PCR assays, followed by full-gene sequencing as reported previously (15). Isolates collected in 2014 were also screened for blaGIM by PCR. Whole-genome sequencing of selected isolates to confirm ambiguous β-lactamase sequences was also performed as described previously (16).

Nucleotide sequence accession numbers.

The sequences of seven new variants were deposited in GenBank with accession no. KM087857 (IMP-48), KP681694 (IMP-49), KP071470 (VIM-42), KP096412 (VIM-43), KP681696 (VIM-44), KP681695 (VIM-45), and KP862821 (NDM-16).

RESULTS

A total of 38,266 isolates of Enterobacteriaceae and 8,010 isolates of P. aeruginosa were collected as part of a global surveillance study from 2012 to 2014. bla genes encoding MBL variants were detected in 163 isolates of Enterobacteriaceae, which consisted of 11 different bacterial species (12 Citrobacter freundii, 1 Enterobacter aerogenes, 4 Enterobacter asburiae, 34 Enterobacter cloacae, 6 Escherichia coli, 7 Klebsiella oxytoca, 78 Klebsiella pneumoniae, 10 Proteus mirabilis, 1 Providencia rettgeri, 5 Providencia stuartii, and 5 Serratia marcescens isolates) and 308 isolates of Pseudomonas aeruginosa. The MBL-producing isolates were collected in 34 of 40 countries that were sampled and came from all regions involved in the study (Table 1; Fig. 1). No isolates of Enterobacteriaceae or P. aeruginosa carrying MBL genes were detected in Ireland, Denmark, the Netherlands, Sweden, or Israel. It should be noted that India was not included in this study due to the current restrictions in strain export from that country (17). Among the MBL-positive Enterobacteriaceae, 44.2% of isolates carried blaNDM, 39.3% carried blaVIM, and 16.5% carried blaIMP. In contrast, the majority of MBL-positive P. aeruginosa isolates carried blaVIM (87.7%), with smaller percentages carrying blaIMP (11.3%) and blaNDM (1.0%). Examples of all three MBL types were found in six species of Enterobacteriaceae (C. freundii, E. cloacae, K. oxytoca, K. pneumoniae, P. mirabilis, and S. marcescens) and P. aeruginosa. No isolates carrying blaSPM or blaGIM were detected even though isolates from Brazil and Germany were included in the study.

TABLE 1.

Distribution of metallo-β-lactamase variants among Enterobacteriaceae and P. aeruginosa isolates collected from 2012 to 2014

Region Country Organism MBL variant (no.)
IMP NDM VIM
Europe Austria E. cloacae VIM-1 (2)
P. aeruginosa VIM-2 (2)
Belgium K. pneumoniae NDM-1 (1)
P. aeruginosa VIM-1 (1)
VIM-2 (8)
Czech Republic P. aeruginosa IMP-7 (6) VIM-2 (2)
France P. aeruginosa VIM-2 (1)
Germany P. stuartii VIM-1 (1)
P. aeruginosa IMP-19 (1) VIM-2 (3)
VIM-28 (2)
Greece C. freundii VIM-1 (1)
E. cloacae VIM-1 (12)
E. coli VIM-1 (1)
K. pneumoniae VIM-1 (13)
VIM-26 (1)
P. mirabilis VIM-1 (4)
P. stuartii VIM-1 (3)
P. aeruginosa VIM-2 (24)
VIM-4 (2)
Hungary C. freundii VIM-4 (1)
K. pneumoniae VIM-4 (2)
S. marcescens VIM-4 (1)
P. aeruginosa VIM-4 (5)
VIM-43 (1)
Italy C. freundii VIM-1 (2)
E. coli VIM-1 (1)
K. pneumoniae VIM-1 (1)
VIM-42 (1)
P. aeruginosa VIM-1 (5)
VIM-2 (1)
Poland P. aeruginosa VIM-2 (1)
Portugal P. aeruginosa VIM-2 (4)
VIM-44 (1)
Romania E. cloacae NDM-1 (4)
K. oxytoca NDM-1 (1)
K. pneumoniae NDM-1 (6)
S. marcescens NDM-1 (2)
P. aeruginosa VIM-2 (10)
VIM-4 (1)
Russia K. pneumoniae NDM-1 (3)
NDM-16 (2)
P. aeruginosa IMP-1 (1) VIM-2 (66)
Spain K. oxytoca VIM-1 (1)
P. aeruginosa VIM-2 (1)
Turkey E. cloacae VIM-31 (1)
K. pneumoniae NDM-1 (1)
S. marcescens VIM-5 (1)
P. aeruginosa VIM-4 (1)
VIM-5 (1)
United Kingdom K. pneumoniae NDM-1 (1)
P. aeruginosa VIM-2 (1)
Asia-Pacific Australia K. pneumoniae IMP-4 (1)
P. stuartii VIM-1 (1)
Chinab C. freundii NDM-1 (1)
E. cloacae IMP-1 (2)
IMP-8 (1)
E. coli NDM-1 (1)
K. oxytoca IMP-4 (3)a
K. pneumoniae IMP-4 (2)
P. aeruginosa VIM-2 (1)
Japan K. pneumoniae IMP-1 (2)
P. aeruginosa IMP-1 (1)
IMP-7 (1)
Malaysia P. aeruginosa IMP-1 (1) VIM-6 (1)
Philippines C. freundii NDM-7 (2)
E. asburiae NDM-7 (1)
E. cloacae IMP-4 (1) NDM-1 (4)
NDM-7 (1)
K. pneumoniae IMP-4 (2) NDM-1 (8)
IMP-26 (4) NDM-7 (2)
P. mirabilis IMP-26 (1) NDM-1 (1)
P. aeruginosa IMP-1 (1)
IMP-26 (5) VIM-2 (21)
South Korea P. aeruginosa IMP-6 (2)
Taiwan C. freundii IMP-8 (3)
E. asburiae IMP-8 (1)
E. cloacae IMP-8 (1)
K. pneumoniae IMP-8 (1)
S. marcescens IMP-47 (1)
P. aeruginosa VIM-2 (1)
Thailand E. asburiae IMP-14 (1)
E. coli NDM-1 (1)
K. pneumoniae NDM-1 (3)
P. aeruginosa IMP-1 (2)
IMP-7 (1) VIM-2 (3)
IMP-14 (1) VIM-5 (2)
IMP-48 (6) VIM-45 (2)
Middle East-Africa Kenya E. asburiae NDM-1 (1)
K. pneumoniae NDM-1 (1)
NDM-5 (2)
P. aeruginosa NDM-1 (3) VIM-2 (2)
Kuwait E. cloacae VIM-4 (2)
E. coli NDM-5 (2)
K. pneumoniae NDM-1 (3)
P. aeruginosa VIM-2 (11)
VIM-4 (3)
Nigeria E. cloacae NDM-1 (1)
K. pneumoniae NDM-1 (9)
P. mirabilis VIM-5 (4)
P. rettgeri NDM-1 (1)
P. aeruginosa VIM-2 (3)
VIM-5 (2)
South Africa K. oxytoca VIM-1 (2)
K. pneumoniae NDM-1 (3)
P. aeruginosa VIM-2 (20)
Latin America Argentina P. aeruginosa IMP-16 (1)
Brazil P. aeruginosa IMP-49 (1) VIM-2 (2)
Chile P. aeruginosa VIM-2 (13)
Colombia P. aeruginosa VIM-2 (8)
Mexico C. freundii VIM-23 (1)
E. aerogenes VIM-23 (1)
E. cloacae VIM-23 (2)
P. aeruginosa IMP-1 (1)
IMP-18 (2) VIM-2 (1)
Venezuela K. pneumoniae NDM-1 (1)
P. aeruginosa VIM-2 (28)
North America United States C. freundii VIM-32 (1)
K. pneumoniae NDM-1 (2)
P. aeruginosa IMP-13 (1) VIM-2 (2)
Open in a new tab
a

The full gene sequence was determined by whole-genome sequencing.

b

No isolates were obtained from patients in mainland China in 2014 due to export restrictions.

FIG 1.

FIG 1

Open in a new tab

Distribution of metallo-β-lactamase-positive Enterobacteriaceae and P. aeruginosa collected from 2012 to 2014.

Multiple sequence variants of each MBL type were identified, with 32 variants (14 VIM-, 14 IMP-, and 4 NDM-type enzymes) detected overall (Table 1). Among the Enterobacteriaceae, 8 VIM-type, 6 IMP-type, and 4 NDM-type MBLs were detected, with VIM-1 (45 of 64 isolates) and NDM-1 (60 of 72 isolates) being the most commonly found variants of these MBL types. No IMP-type variant predominated, although four variants (IMP-4 [n = 9], IMP-8 [n = 7], IMP-26 [n = 5], and IMP-1 [n = 4]) accounted for 25 of 27 IMP-positive isolates. In comparison, 9 VIM-type and 11 IMP-type variants as well as NDM-1 were detected in P. aeruginosa isolates, with VIM-2 the most frequently detected VIM-type MBL (240 of 270 isolates). The next most abundant MBL types detected in P. aeruginosa were VIM-4 (12 isolates), IMP-7 (8 isolates), and IMP-1 (7 isolates).

Seven novel MBL variants, each differing from a previously reported variant by one amino acid substitution, were identified in six countries as part of this study (Table 2). VIM-42 (VIM-1 [V223I]) and NDM-16 (NDM-1 [R264H]) were found in K. pneumoniae, whereas IMP-48 (IMP-14 [I69T]), IMP-49 (IMP-18 [V49F]), VIM-43 (VIM-4 [A24V]), VIM-44 (VIM-2 [K257N]), and VIM-45 (VIM-2 [T35I]) were each found in P. aeruginosa. Each new variant was detected in one or two isolates from a single medical center with the exception of IMP-48, which was detected in six isolates collected from two medical centers in Thailand in consecutive years (2013 and 2014). The presumed “progenitor” variant was also detected in each country except Brazil (Table 1). Six of the eight isolates from Thailand (two IMP-48-positive isolates from each medical center and both VIM-45-positive isolates) were collected within a 3-week period in 2014, suggesting possible outbreaks or endemicity. The two NDM-16-positive isolates from Russia were collected 4 months apart at the same medical center (data not shown). Two P. aeruginosa isolates carrying VIM-43 were collected from the same center on the same day and were deemed to be duplicate isolates based upon the patient and sample data provided. The second isolate was excluded from analysis.

TABLE 2.

Activities of aztreonam-avibactam and comparator antimicrobial agents tested against isolates carrying new MBL variants collected in 2013 and 2014

Yr collectedc Country Organism Enzyme contentd Sourcee Wardf MIC (μg/ml)a,b
ATM ATM-AVI FEP MEM IPM AMK CST LVX TGC
2013 Thailand P. aeruginosag IMP-48 RTI 1 128 128 >16 >8 >8 >32 NAj >4 >8
2014 Thailand P. aeruginosag IMP-48 IAI 3i 64 64 >16 >8 >8 >32 2 >4 >8
2014 Thailand P. aeruginosag IMP-48 RTI 1 64 64 >16 >8 >8 >32 2 >4 >8
2014 Thailand P. aeruginosah IMP-48 SSTI 3 64 64 >16 >8 >8 >32 4 >4 >8
2014 Thailand P. aeruginosah IMP-48 RTI 4 16 2 >16 >8 >8 >32 2 >4 >8
2014 Thailand P. aeruginosah IMP-48 SSTI 4 128 64 >16 >8 >8 >32 2 >4 >8
2014 Brazil P. aeruginosa IMP-49 Blood 5 8 8 >16 >8 4 >32 2 1 8
2013 Italy K. pneumoniae VIM-42, SHV-12 UTI 3 64 0.06 >16 8 8 16 NA >4 2
2014 Hungary P. aeruginosa VIM-43k IAI 4 8 8 >16 >8 >8 >32 2 >4 >8
2014 Portugal P. aeruginosa VIM-44 RTI 4 4 4 8 4 8 >32 2 1 >8
2014 Thailand P. aeruginosag VIM-45, VEB-1b RTI 4 >128 64 >16 >8 >8 >32 2 >4 8
2014 Thailand P. aeruginosag VIM-45, VEB-1b RTI 1 >128 128 >16 >8 >8 >32 2 >4 >8
2014 Russia K. pneumoniae NDM-16, CTX-M-15, SHV-OSBL, TEM-OSBL Blood 1 64 0.12 >16 >8 >8 >32 0.5 >4 0.25
2014 Russia K. pneumoniae NDM-16, CTX-M-15, SHV-12, TEM-OSBL Blood 2 >128 0.25 >16 >8 >8 >32 1 >4 0.5
Open in a new tab
a

ATM, aztreonam; ATM-AVI, aztreonam-avibactam; FEP, cefepime; MEM, meropenem; IPM, imipenem; AMK, amikacin; CST, colistin, LVX, levofloxacin; TGC, tigecycline.

b

Colistin was tested with 0.002% polysorbate 80 against isolates collected in 2012 and 2013 per the recommendation of the CLSI Enterobacteriaceae Working Group and tested with and without polysorbate 80 against isolates collected in 2014. Values for colistin tested without polysorbate 80 are shown.

c

Multiple isolates collected from the same site are listed chronologically according to collection date.

d

OSBL, original-spectrum β-lactamase; includes TEM-1, TEM-2, SHV-1, and SHV-11.

e

RTI, respiratory tract infection; SSTI, skin and soft tissue infection; blood, bloodstream; UTI, urinary tract infection; IAI, intra-abdominal infection.

f

Ward types: 1, surgery general; 2, surgery ICU; 3, medicine general, 4, medicine ICU; 5, pediatric ICU.

g

Isolates were collected from one of two medical centers that contributed 90.9% of MBL-positive isolates from Thailand.

h

Isolates were collected from one of two medical centers that contributed 90.9% of MBL-positive isolates from Thailand.

i

Isolate was collected on the day of admittance. All other isolates were collected after ≥48 h of hospitalization.

j

NA, not available (not determined).

k

Two P. aeruginosa isolates carrying VIM-43 were collected from the same medical center on the same day and were deemed to be duplicate isolates based upon patient and sample data provided by the investigator. The second isolate was excluded from analysis.

The distribution of MBL-positive organisms and MBL types varied by region (Table 1; Fig. 1). In Europe and Latin America, the majority of MBL-positive isolates collected were P. aeruginosa, whereas relatively equal numbers of MBL-positive Enterobacteriaceae and P. aeruginosa isolates were collected in Asia-Pacific, the Middle East-Africa, and the United States. Isolates carrying each of the three MBL types were found in all regions except the Middle East-Africa, where no IMP-positive isolates were identified. VIM-positive isolates predominated in Europe and Latin America, comprising 87 to 90% of the MBL-positive organisms collected in these two regions. Three-fourths of the IMP-positive isolates collected globally (77.4%; 48 of 62 global isolates), including all 27 IMP-positive Enterobacteriaceae, were found in Asia-Pacific. NDM-positive organisms were found in all regions, with the greatest numbers collected in Philippines, Romania, Nigeria, and Kenya. Notably, the only NDM-positive P. aeruginosa isolates identified during this study were collected from two medical centers in Kenya.

The in vitro activities of aztreonam-avibactam and comparator antimicrobial agents were determined against the overall collection of Enterobacteriaceae and P. aeruginosa and subsets of isolates that carried each MBL type (Table 3). The overall MIC90 for aztreonam-avibactam against Enterobacteriaceae isolates was 0.12 μg/ml, which was >256-fold lower than the MIC90 for aztreonam alone (64 μg/ml). Aztreonam-avibactam resulted in MIC90s of 0.5 to 1 μg/ml against MBL-positive isolates, compared to MIC90s of 128 to >128 μg/ml for aztreonam. All MBL-positive Enterobacteriaceae isolates were inhibited by ≤8 μg/ml of aztreonam-avibactam. In contrast, the activities of most other tested agents against MBL-positive isolates were greatly reduced. Based on CLSI breakpoints, 75.7% of the overall collection of Enterobacteriaceae was susceptible to aztreonam alone, but only 20.8%, 29.6%, and 48.4% of NDM-, IMP-, and VIM-positive subsets, respectively, were susceptible to this single agent due to the coproduction of Ambler class A and class C serine β-lactamases. The activities of other β-lactams against MBL-positive isolates were also decreased substantially, with susceptibilities of <8% for ceftazidime and cefepime, <19% for meropenem, and <41% for piperacillin-tazobactam, compared to 76.9%, 78.8%, 97.3%, and 84.7%, respectively, against the overall collection. The activities of agents from other drug classes were also impacted; 96.6% of the overall collection was susceptible to amikacin, but the susceptibility of VIM-positive isolates was 79.7%, and it was further reduced for IMP-positive (66.7%) and for NDM-positive (41.7%) isolates. Similarly, the susceptibility of the overall population to levofloxacin was 75.7%, but it was reduced to 55.6% for IMP-positive isolates and 22 to 28% for NDM- and VIM-positive subsets. Tigecycline and colistin retained greater activity against MBL-positive isolates than other comparators. Using FDA breakpoints, 89.0% of MBL-positive isolates were susceptible to tigecycline, compared to 92.9% of all Enterobacteriaceae isolates. For colistin, these percentages were 80.4% and 83.2%, respectively, using breakpoints defined by EUCAST (Table 3).

TABLE 3.

In vitro activities of β-lactams and comparators tested against Enterobacteriaceae and P. aeruginosa encoding metallo-β-lactamases collected from 2012 to 2014

Organism, genotype (no.), and druga MIC (μg/ml)
 % susceptibleb
Range MIC50 MIC90 CLSI EUCAST
All Enterobacteriaceae (38,266)
    Ceftazidime ≤0.015 to >128 0.25 64 76.9 73.4
    Cefepime ≤0.12 to >16 ≤0.12 >16 78.8 77.0
    Aztreonam ≤0.015 to >128 0.12 64 75.7 73.1
    Aztreonam-avibactamc ≤0.015 to >128 0.03 0.12 NAd NA
    Piperacillin-tazobactam ≤0.25 to >128 2 64 84.7 78.1
    Meropenem ≤0.004 to >8 0.03 0.12 97.3 97.7
    Amikacin ≤0.25 to >32 2 8 96.6 93.8
    Tigecycline ≤0.015 to >8 0.5 2 92.9 82.5
    Levofloxacin ≤0.03 to >4 0.06 >4 75.7 73.5
    Colistin ≤0.015 to >4 ≤0.12 >4 NA 83.2
MBL-positive Enterobacteriaceae
    NDM positive (72)
        Ceftazidime 128 to >128 >128 >128 0.0 0.0
        Cefepime 1 to >16 >16 >16 0.0 1.4
        Aztreonam ≤0.015 to >128 128 >128 20.8 16.7
        Aztreonam-avibactam ≤0.015 to 8 0.12 0.5 NA NA
        Piperacillin-tazobactam 32 to >128 >128 >128 0.0 0.0
        Meropenem 1 to >8 >8 >8 1.4 2.8
        Amikacin 1 to >32 >32 >32 41.7 37.5
        Tigecycline 0.06 to 8 1 4 87.5 61.1
        Levofloxacin 0.06 to >4 >4 >4 22.2 12.5
        Colistin ≤0.015 to >4 ≤0.12 >4 NA 86.1
    IMP positive (27)
        Ceftazidime 64 to >128 >128 >128 0.0 0.0
        Cefepime 8 to >16 >16 >16 0.0 0.0
        Aztreonam 0.06 to >128 64 >128 29.6 29.6
        Aztreonam-avibactam 0.03 to 4 0.25 1 NA NA
        Piperacillin-tazobactam 0.5 to >128 128 >128 40.7 25.9
        Meropenem 0.5 to >8 4 >8 18.5 40.7
        Amikacin 1 to >32 2 >32 66.7 59.3
        Tigecycline 0.12 to 8 1 2 96.3 77.8
        Levofloxacin 0.06 to >4 2 >4 55.6 40.7
        Colistin 0.03 to >4 ≤0.12 >4 NA 88.9
    VIM positive (64)
        Ceftazidime 0.25 to >128 >128 >128 6.3 6.3
        Cefepime ≤0.12 to >16 >16 >16 7.8 7.8
        Aztreonam ≤0.015 to >128 8 128 48.4 42.2
        Aztreonam-avibactam ≤0.015 to 2 0.12 1 NA NA
        Piperacillin-tazobactam 1 to >128 >128 >128 6.3 1.6
        Meropenem 0.25 to >8 8 >8 14.1 25.0
        Amikacin 1 to >32 8 >32 79.7 59.4
        Tigecycline 0.25 to >8 1 4 87.5 60.9
        Levofloxacin 0.06 to >4 >4 >4 28.1 23.4
        Colistin 0.03 to >4 ≤0.12 >4 NA 70.3
All P. aeruginosa (8,010)
    Ceftazidime 0.06 to >128 2 64 77.4 77.4
    Cefepime ≤0.12 to >16 4 16 78.6 78.6
    Aztreonam ≤0.015 to >128 8 32 61.4 3.4
    Aztreonam-avibactamc ≤0.015 to >128 8 32 NA NA
    Piperacillin-tazobactam ≤0.25 to >128 8 >128 69.1 69.1
    Meropenem ≤0.06 to >8 0.5 >8 73.3 73.3
    Amikacin ≤0.25 to >32 4 16 90.2 85.1
    Levofloxacin ≤0.03 to >4 0.5 >4 71.7 63.2
    Colistin ≤0.06 to >8 0.5 1 99.5 99.7
MBL-positive P. aeruginosa
    NDM positive (3)
        Ceftazidime >128 0.0 0.0
        Cefepime >16 0.0 0.0
        Aztreonam >128 0.0 0.0
        Aztreonam-avibactam 16 to >128 NA NA
        Piperacillin-tazobactam >128 0.0 0.0
        Meropenem >8 0.0 0.0
        Amikacin >32 0.0 0.0
        Levofloxacin >4 0.0 0.0
        Colistin ≤0.06 to 2 100 100
    IMP positive (35)
        Ceftazidime 64 to >128 >128 >128 0.0 0.0
        Cefepime >16 >16 >16 0.0 0.0
        Aztreonam 4 to >128 32 128 17.1 0.0
        Aztreonam-avibactam 2 to 128 32 64 NA NA
        Piperacillin-tazobactam 4 to >128 128 >128 14.3 14.3
        Meropenem 4 to >8 >8 >8 0.0 0.0
        Amikacin 4 to >32 32 >32 40.0 28.6
        Levofloxacin 1 to >4 >4 >4 5.7 5.7
        Colistin 0.12 to 4 0.5 2 97.1 100
    VIM positive (270)
        Ceftazidime 2 to >128 64 >128 3.0 3.0
        Cefepime 8 to >16 >16 >16 4.4 4.4
        Aztreonam 0.5 to >128 16 64 27.8 0.4
        Aztreonam-avibactam 0.25 to >128 16 32 NA NA
        Piperacillin-tazobactam 16 to >128 64 >128 3.7 3.7
        Meropenem 1 to >8 >8 >8 2.2 2.2
        Amikacin 0.5 to >32 >32 >32 16.7 11.1
        Levofloxacin 0.25 to >4 >4 >4 6.3 5.2
        Colistin ≤0.06 to 2 0.5 1 100 100
Open in a new tab
a

Colistin was tested with 0.002% polysorbate 80 against isolates collected in 2012 and 2013 per the recommendation of the CLSI Enterobacteriaceae Working Group and tested with and without polysorbate 80 against isolates collected in 2014. Values for colistin tested with 0.002% polysorbate 80 are shown.

b

CLSI susceptibilities were defined by CLSI document M100-S25 (14). Tigecycline susceptibilities in the CLSI category were defined by the FDA (54). EUCAST susceptibilities were defined by Breakpoint Tables for Interpretation of MICs and Zone Diameters, version 5.0 (55).

c

Aztreonam-avibactam was tested at a fixed concentration of 4 μg/ml of avibactam.

d

NA, not applicable (no breakpoint defined).

The overall MIC90 of aztreonam-avibactam against P. aeruginosa was 32 μg/ml (Table 3). Meropenem was also relatively inactive against this species, with only 73.3% of isolates being susceptible to meropenem. Amikacin and colistin were the only agents for which a susceptibility of >90% within the overall collection was found. Aztreonam-avibactam showed a modest (2-fold) increase in activity against VIM- and IMP-positive isolates of P. aeruginosa compared to that of aztreonam alone (MIC90s of 32 to 64 μg/ml). Colistin was the only agent that retained significant activity against IMP-, VIM-, and NDM-positive subsets of P. aeruginosa (>97% susceptible).

A total of 98.7% of MBL-positive isolates also carried 1 to 5 genes encoding serine β-lactamases from Amber class A, C, or D detected by PCR or intrinsic chromosomally encoded AmpC and ESBL enzymes common to Citrobacter spp., Enterobacter spp., Providencia spp., Serratia spp., P. aeruginosa, and K. oxytoca that were presumed to be present, though this was not confirmed by molecular methods (Table 4). Of the MBL-positive isolates, only 24 were negative for any additional serine bla gene or carried only an original-spectrum β-lactamase (OSBL) that would not hydrolyze aztreonam. A small number of MBL-positive isolates also carried genes encoding KPC or OXA-48 carbapenemases, with or without additional serine β-lactamases. One P. aeruginosa isolate collected in Chile carried VIM-2 and KPC-2. Four K. pneumoniae isolates from Greece carried VIM-1 and KPC-2, three of which also coproduced additional class A and class C enzymes, and two K. oxytoca isolates from China carried IMP-4, KPC-2, and SHV-12. Three E. cloacae isolates carried VIM-type enzymes (VIM-4, Kuwait; VIM-31, Turkey) in combination with OXA-48. Three K. pneumoniae isolates collected in Romania carried NDM-1, OXA-48, and CTX-M-15, whereas one K. pneumoniae isolate from Belgium carried NDM-1 and OXA-232.

TABLE 4.

Cocarriage of metallo-β-lactamases and serine β-lactamases in Enterobacteriaceae and P. aeruginosa collected from 2012 to 2014a

MBL and serine β-lactamase Organism No. of isolates Molecular variant(s)
MBL + KPC K. pneumoniae 1 VIM-1, KPC-2
MBL + KPC + ESBL + AmpC + OSBLb K. pneumoniae 2 VIM-1, KPC-2, SHV-12, CMY-13, TEM-OSBL
MBL + KPC + ESBL K. oxytoca 2 IMP-4, KPC-2, SHV-12
MBL + KPC + AmpC P. aeruginosac 1 VIM-2, KPC-2
MBL + KPC + AmpC + OSBL K. pneumoniae 1 VIM-1, KPC-2, MOX-1, SHV-OSBL
MBL + OXA carbapenemase + ESBL + AmpC + OSBL E. cloacaec 1 VIM-4, OXA-48, SHV-12, CMY-4, TEM-OSBL
MBL + OXA carbapenemase + ESBL + OSBL K. pneumoniae 3 NDM-1, OXA-48, CTX-M-15, SHV-OSBL
MBL + OXA carbapenemase + AmpC E. cloacaec 1 VIM-4, OXA-48, CMY-4
1 VIM-31, OXA-48
MBL + OXA carbapenemase + OSBL K. pneumoniae 1 NDM-1, OXA-232, SHV-OSBL
MBL + ESBL + AmpC ± OSBL C. freundiic 1 IMP-8, SHV-12, TEM-OSBL
2 VIM-1, SHV-12
1 VIM-4, CTX-M-15, TEM-OSBL
1 NDM-1, CTX-M-3, SHV-12, TEM-OSBL
E. asburiaec 1 IMP-8, SHV-12, TEM-OSBL
1 NDM-1, VEB-1, TEM-OSBL
E. cloacaec 1 IMP-8, SHV-12, TEM-OSBL
1 IMP-8, CTX-M-22, TEM-OSBL
1 VIM-1, CTX-M-14, TEM-OSBL
1 NDM-1, CTX-M-15
4 NDM-1, CTX-M-15, TEM-OSBL
2 NDM-1, CTX-M-15, SHV-31, TEM-OSBL
K. oxytocad 1 VIM-1, ACC-1
1 NDM-1, ACC-1, TEM-OSBL
K. pneumoniae 1 IMP-26, CTX-M-15, DHA-1, SHV-OSBL, TEM-OSBL
1 NDM-1, CTX-M-15, CMY-6, SHV-OSBL, TEM-OSBL
1 NDM-1, CTX-M-15, CMY-6, DHA-type, SHV-OSBL, TEM-OSBL
P. stuartiic 1 VIM-1, SHV-5, TEM-OSBL
3 VIM-1, SHV-5, VEB-1, TEM-OSBL
S. marcescensc 2 NDM-1, CTX-M-15, TEM-OSBL
P. aeruginosac 1 VIM-2, SHV-2A
2 VIM-2, SHV-12
1 VIM-2, GES-1
4 VIM-2, PER-1
1 VIM-2, VEB-1b
1 VIM-2, VEB-1
1 VIM-4, SHV-12
1 VIM-5, PER-1
2 VIM-5, VEB-14e
2 VIM-45, VEB-1bf
2 NDM-1, VEB-1a
MBL + ESBL ± OSBL E. coli 1 NDM-1, CTX-M-3
1 NDM-1, CTX-M-27
K. oxytocad 1 IMP-4f
2 VIM-1
K. pneumoniae 1 IMP-1, CTX-M-3, SHV-OSBL
2 IMP-4, CTX-M-15, SHV-OSBL
1 IMP-4, CTX-M-15, SHV-OSBL, TEM-OSBL
1 IMP-26, CTX-M-15, SHV-28
1 IMP-26, CTX-M-15, SHV-OSBL
1 IMP-26, CTX-M-15, SHV-OSBL, TEM-OSBL
2 VIM-1, SHV-12
2 VIM-4, CTX-M-15, SHV-OSBL, TEM-OSBL
1 VIM-26, SHV-5
1 VIM-42, SHV-12
1 NDM-1, CTX-M-15
9 NDM-1, CTX-M-15, SHV-OSBL
16 NDM-1, CTX-M-15, SHV-OSBL, TEM-OSBL
1 NDM-1, CTX-M-15, SHV-12
1 NDM-1, CTX-M-15, SHV-12, TEM-OSBL
1 NDM-1, CTX-M-15, SHV-55, TEM-OSBL
1 NDM-1, CTX-M-15, SHV-134, TEM-OSBL
1 NDM-1, CTX-M-15, CTX-M-27, TEM-OSBL
1 NDM-5, CTX-M-15, SHV-OSBL, TEM-OSBL
2 NDM-7, CTX-M-15, SHV-12, TEM-OSBL
1 NDM-16, CTX-M-15, SHV-OSBL, TEM-OSBL
1 NDM-16, CTX-M-15, SHV-12, TEM-OSBL
P. mirabilis 1 VIM-1, SHV-5, VEB-1, TEM-OSBL
1 VIM-1, VEB-1, TEM-OSBL
MBL + AmpC ± OSBL C. freundiic 2 IMP-8, TEM-OSBL
1 VIM-1
1 VIM-23
1 VIM-32
1 NDM-7, DHA-1
1 NDM-7, TEM-OSBL
E. aerogenesc 1 VIM-23
E. asburiaec 1 IMP-14
1 NDM-7
E. cloacaec 2 IMP-1
1 IMP-4
6 VIM-1
7 VIM-1, TEM-OSBL
2 VIM-23
2 NDM-1, DHA-1, TEM-OSBL
1 NDM-7
E. coli 1 VIM-1, ACT-24, TEM-OSBL
1 NDM-5, CMY-42
1 NDM-5, CMY-42, TEM-OSBL
P. mirabilis 1 IMP-26, DHA-1
2 VIM-1, CMY-16, TEM-OSBL
P. rettgeric 1 NDM-1, TEM-OSBL
P. stuartiic 1 VIM-1, CMY-2
S. marcescensc 1 IMP-47, TEM-OSBL
1 VIM-4
1 VIM-5
P. aeruginosac 6 IMP-1
1 IMP-1, TEM-OSBL
2 IMP-6
8 IMP-7
1 IMP-13
1 IMP-14
1 IMP-16
2 IMP-18
1 IMP-19
5 IMP-26
6 IMP-48
1 IMP-49
6 VIM-1
228 VIM-2
1 VIM-2, TEM-OSBL
11 VIM-4
2 VIM-5
1 VIM-6
2 VIM-28
1 VIM-43
1 VIM-44
1 NDM-1
MBL + OSBL E. coli 1 VIM-1, SHV-OSBL
K. pneumoniae 1 IMP-1, SHV-OSBL
1 IMP-4, SHV-OSBL, TEM-OSBL
1 IMP-4, TEM-OSBL
1 IMP-8, SHV-OSBL
8 VIM-1, SHV-OSBL
4 NDM-1, SHV-OSBL
1 NDM-5, SHV-OSBL
Open in a new tab
a

Serine β-lactamases were not detected by PCR in 6 MBL-positive Enterobacteriaceae isolates (1 K. pneumoniae isolate and 5 P. mirabilis isolates).

b

OSBL, original spectrum β-lactamase; includes TEM-1, TEM-2, SHV-1, and SHV-11.

c

Presumed to also carry the intrinsic chromosomally encoded AmpC β-lactamase common to this species.

d

Presumed to also carry the intrinsic chromosomally encoded ESBL common to this species.

e

S. Lahiri (formerly of AstraZeneca Pharmaceuticals), personal communication.

f

The full gene sequence was determined by whole-genome sequencing.

In contrast, the percentages of MBL-positive isolates that carried genes encoding ESBL and AmpC enzymes (9.8%), only ESBLs (11.9%), or only AmpC β-lactamases (70.3%) were much higher. NDM-type and CTX-M-type β-lactamases were detected in 50 isolates of K. pneumoniae, E. cloacae, C. freundii, E. coli, and S. marcescens, 47 of which also carried CTX-M-15. Ten of 47 isolates carried an additional ESBL (SHV-type enzyme or CTX-M-27), and 2 carried additional plasmid-mediated AmpC enzymes. VIM-1 was cocarried with SHV-type, CTX-M-14, or VEB-1 ESBLs in C. freundii, E. cloacae, P. mirabilis, P. stuartii, and K. pneumoniae isolates, whereas VIM-4 plus CTX-M-15 was detected in C. freundii and K. pneumoniae. IMP-8 along with SHV-12 or CTX-M-22 was detected in C. freundii and Enterobacter spp., and IMP-26 plus CTX-M-15 was found in K. pneumoniae. Sixteen VIM-positive P. aeruginosa isolates also contained PER-, VEB-, SHV-, and GES-type ESBLs, and two isolates contained NDM-1 and VEB-1a.

DISCUSSION

This 2012-2014 global surveillance program provided a contemporary perspective on the species, regions, and types of MBL-producing pathogens that are a significant concern among patient infections. Although this surveillance program was not designed to be a prevalence study, the incidence and distribution of MBL-positive isolates resembled those reported by others, with VIM-type MBLs predominating in Europe and Latin America but found globally, IMP-type enzymes most common in Asia-Pacific, and NDM-type enzymes found in all regions but in higher numbers in countries in the Balkan region and the Middle East-Africa (18–22). It is unfortunate that medical centers in India did not contribute isolates to this study, as a high prevalence of MBL-producing isolates from the Indian subcontinent has previously been reported (23, 24). While isolates carrying blaSPM have been reported to be endemic in Brazil, surprisingly, no isolates carrying blaSPM were detected in that country during the 3 years of this study (25). Multiple MBL-positive isolates were detected in Russia and Greece, and the prevalence and spread of MBL-positive organisms within and from these countries have been reported previously (18, 26–28). In this study, the large number of MBL-positive organisms isolated in Philippines, which included 5 different species of Enterobacteriaceae and P. aeruginosa carrying genes for all three MBL types, exceeded those in previous reports and might suggest a strong potential for further spread in diverse geographic regions (29, 30).

Some variants were detected in one or several species of Enterobacteriaceae, whereas others were found in both Enterobacteriaceae and P. aeruginosa isolates, suggesting that these variants were encoded on mobilizable elements with large host ranges. blaVIM and blaIMP are commonly found as gene cassettes within class 1 integrons that can be mobilized by transposition or plasmid conjugation (3, 21, 31). blaNDM-1 is often flanked by ISAba125 and bleMBL and has been found on both narrow- and broad-host range plasmids belonging to at least 8 incompatibility groups, many of which are readily transmissible within and between species (19). These three MBL types have been identified in multiple lineages of Enterobacteriaceae species and P. aeruginosa (19, 21). MBLs can also spread clonally, and some have been associated with successful high-risk sequence types (STs), such as P. aeruginosa ST111 and ST235 and E. coli ST131 and ST405 (32–35).

Although only a small number of isolates coproducing MBLs and serine carbapenemases were identified during this study, similar isolates have been reported by others, though they appear to be rare. Isolates producing KPC-2 and VIM-type MBLs (36–43) and K. pneumoniae carrying NDM-1 and OXA-48 or OXA-232 (44–47) have been reported previously. Although E. cloacae isolates carrying VIM-31, VIM-4 and CMY-4, or OXA-48 are known, this is the first report of isolates carrying OXA-48 in combination with those VIM types (48–50).

Infections caused by MBL-positive isolates pose a grave health challenge. Genes encoding MBLs have disseminated to several difficult-to-treat ESKAPE pathogens and to species that are naturally resistant to colistin (Proteeae and Serratia spp.) and tigecycline (Proteeae and P. aeruginosa) (51, 52). Furthermore, resistance mechanisms against non-β-lactam classes of antimicrobials, such as aminoglycosides and fluoroquinolones, are often transferred with bla genes encoding MBLs (19, 31, 53). As a result, many MBL-containing isolates are truly multidrug resistant, with limited options for treatment. Although aztreonam is stable to hydrolysis by MBLs, the majority of MBL-positive isolates coproduce one or more serine β-lactamases that can hydrolyze aztreonam and are therefore resistant to this agent. Combining aztreonam with avibactam would alleviate this issue, and the activity of aztreonam-avibactam against MBL-positive Enterobacteriaceae, including isolates harboring MBLs and serine carbapenemases, is noteworthy. However, colistin appears to be the only agent active against MBL-producing P. aeruginosa. The greatly diminished susceptibility of MBL-positive isolates to most antimicrobials and limited therapeutic options currently available demand continued monitoring and research into the development of new inhibitors of this formidable class of enzymes.

ACKNOWLEDGMENTS

AstraZeneca Pharmaceuticals provided financial support for this investigation. The authors generated data and/or provided analysis input, and all authors have read and approved the final manuscript.

We thank Boudewijn de Jonge (AstraZeneca Pharmaceuticals) for critical reading of the manuscript and Sushmita Lahiri (formerly of AstraZeneca Pharmaceuticals) for communicating the sequence of VEB-14 before public release. We gratefully acknowledge the contributions of the clinical trial investigators, laboratory personnel, and all members of the global surveillance program who contributed isolates and information for this study.

K.M.K., S.R., M.H., D.J.B., S.K.B., and D.F.S. are employees of International Health Management Associates, Inc. (IHMA). None of the IHMA authors have personal financial interests in the sponsor of this paper (AstraZeneca Pharmaceuticals). P.A.B. and R.E.M. are employees and stockholders of AstraZeneca Pharmaceuticals LP.

Funding Statement

This investigation was funded by AstraZeneca Pharmaceuticals as part of a sponsored global surveillance program. The sponsor approved the overall study design. All investigative sites were recruited and study supplies were provided by IHMA. Analysis of the final MIC and molecular data was performed by IHMA and was independent of sponsor analysis for this study.

REFERENCES

  • 1.Bradford PA. 2001. Extended-spectrum β-lactamases in the 21st century: characterization, epidemiology, and detection of this important resistance threat. Clin Microbiol Rev 14:933–951. doi: 10.1128/CMR.14.4.933-951.2001. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 2.Paterson DL, Bonomo RA. 2005. Extended-spectrum β-lactamases: a clinical update. Clin Microbiol Rev 18:657–686. doi: 10.1128/CMR.18.4.657-686.2005. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 3.Walsh TR, Toleman MA, Poirel L, Nordmann P. 2005. Metallo-β-lactamases: the quiet before the storm? Clin Microbiol Rev 18:306–325. doi: 10.1128/CMR.18.2.306-325.2005. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 4.Nordmann P, Naas T, Poirel L. 2011. Global spread of carbapenemase-producing Enterobacteriaceae. Emerg Infect Dis 17:1791–1798. doi: 10.3201/eid1710.110655. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 5.Glasner C, Albiger B, Buist G, Tambić Andrasević A, Canton R, Carmeli Y, Friedrich AW, Giske CG, Glupczynski Y, Gniadkowski M, Livermore DM, Nordmann P, Poirel L, Rossolini GM, Seifert H, Vatopoulos A, Walsh T, Woodford N, Donker T, Monnet DL, Grundmann H, the European Survey on Carbapenemase-Producing Enterobacteriaceae (EuSCAPE) Working Group . 2013. Carbapenemase-producing Enterobacteriaceae in Europe: a survey among national experts from 39 countries, February 2013. Euro Surveill 18(28):pii=20525. [DOI] [PubMed] [Google Scholar]
  • 6.Palzkill T. 2013. Metallo-β-lactamase structure and function. Ann N Y Acad Sci 1277:91–104. doi: 10.1111/j.1749-6632.2012.06796.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 7.Biedenbach DJ, Kazmierczak K, Bouchillon SK, Sahm DF, Bradford PA. 2015. In vitro activity of aztreonam-avibactam against a global collection of Gram-negative pathogens from 2012 and 2013. Antimicrob Agents Chemother 59:4239–4248. doi: 10.1128/AAC.00206-15. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 8.Bush K, Fisher JF. 2011. Epidemiological expansion, structural studies, and clinical challenges of new β-lactamases from Gram-negative bacteria. Annu Rev Microbiol 65:455–478. doi: 10.1146/annurev-micro-090110-102911. [DOI] [PubMed] [Google Scholar]
  • 9.Coleman K. 2011. Diazabicyclooctanes (DBOs): a potent new class of non-β-lactam β-lactamase inhibitors. Curr Opin Microbiol 14:550–555. doi: 10.1016/j.mib.2011.07.026. [DOI] [PubMed] [Google Scholar]
  • 10.Zhanel GG, Lawson CD, Adam H, Schweizer F, Zelenitsky S, Lagace-Wiens PR, Denisuik A, Rubinstein E, Gin AS, Hoban DJ, Lynch JP III, Karlowsky JA. 2013. Ceftazidime-avibactam: a novel cephalosporin/β-lactamase inhibitor combination. Drugs 73:159–177. doi: 10.1007/s40265-013-0013-7. [DOI] [PubMed] [Google Scholar]
  • 11.Livermore DM, Mushtaq S, Warner M, Zhang J, Maharjan S, Doumith M, Woodford N. 2011. Activities of NXL104 combinations with ceftazidime and aztreonam against carbapenemase-producing Enterobacteriaceae. Antimicrob Agents Chemother 55:390–394. doi: 10.1128/AAC.00756-10. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 12.Li H, Estabrook M, Jacoby GA, Nichols WW, Testa RT, Bush K. 2015. In vitro susceptibility of characterized β-lactamase-producing strains tested with avibactam combinations. Antimicrob Agents Chemother 59:1789–1793. doi: 10.1128/AAC.04191-14. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 13.Clinical and Laboratory Standards Institute. 2012. Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically; approved standards, 9th ed CLSI document M07-A9. Clinical and Laboratory Standards Institute, Wayne, PA. [Google Scholar]
  • 14.Clinical and Laboratory Standards Institute. 2015. Performance standards for antimicrobial susceptibility testing; twenty-fifth informational supplement. CLSI document M100-S25. Clinical and Laboratory Standards Institute, Wayne, PA. [Google Scholar]
  • 15.Lob SH, Kazmierczak KM, Badal RE, Hackel MA, Bouchillon SK, Biedenbach DJ, Sahm DF. 2015. Trends in susceptibility of Escherichia coli from intra-abdominal infections to ertapenem and comparators in the United States according to data from the SMART program, 2009 to 2013. Antimicrob Agents Chemother 59:3606–3610. doi: 10.1128/AAC.05186-14. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 16.Lahiri SD, Johnstone MR, Ross PL, McLaughlin RE, Olivier NB, Alm RA. 2014. Avibactam and class C β-lactamases: mechanism of inhibition, conservation of the binding pocket, and implications for resistance. Antimicrob Agents Chemother 58:5704–5713. doi: 10.1128/AAC.03057-14. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 17.Goossens H. 2013. The Chennai declaration on antimicrobial resistance in India. Lancet 13:105–106. doi: 10.1016/S1473-3099(12)70346-8. [DOI] [PubMed] [Google Scholar]
  • 18.Cantón R, Akova M, Carmeli Y, Giske CG, Glupczynski Y, Gniadkowski M, Livermore DM, Miriagou V, Naas T, Rossolini GM, Samuelsen O, Seifert H, Woodford N, Nordmann P, European Network on Carbapenemases . 2012. Rapid evolution and spread of carbapenemases among Enterobacteriaceae in Europe. Clin Microbiol Infect 18:413–431. doi: 10.1111/j.1469-0691.2012.03821.x. [DOI] [PubMed] [Google Scholar]
  • 19.Johnson AP, Woodford N. 2013. Global spread of antibiotic resistance: the example of New Delhi metallo-β-lactamase (NDM)-mediated carbapenem resistance. J Med Microbiol 62:499–513. doi: 10.1099/jmm.0.052555-0. [DOI] [PubMed] [Google Scholar]
  • 20.Nordmann P, Poirel L. 2014. The difficult-to-control spread of carbapenemase producers among Enterobacteriaceae worldwide. Clin Microbiol Infect 20:821–830. doi: 10.1111/1469-0691.12719. [DOI] [PubMed] [Google Scholar]
  • 21.Hong DJ, Bae IK, Jang I-H, Jeong SH, Kang H-K, Lee K. 2015. Epidemiology and characteristics of metallo-β-lactamase-producing Pseudomonas aeruginosa. Infect Chemother 47:81–97. doi: 10.3947/ic.2015.47.2.81. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 22.Potron A, Poirel L, Nordmann P. 2015. Emerging broad-spectrum resistance in Pseudomonas aeruginosa and Acinetobacter baumannii: mechanisms and epidemiology. Int J Antimicrob Agents 45:568–585. doi: 10.1016/j.ijantimicag.2015.03.001. [DOI] [PubMed] [Google Scholar]
  • 23.Kumarasamy KK, Toleman MA, Walsh TR, Bagaria J, Butt F, Balakrishnan R, Chaudhary U, Doumith M, Giske CG, Irfan S, Krishnan P, Kumar AV, Maharjan S, Mushtaq S, Noorie T, Paterson DL, Pearson A, Perry C, Pike R, Rao B, Ray U, Sarma JB, Sharma M, Sheridan E, Thirunarayan MA, Turton J, Upadhyay S, Warner M, Welfare W, Livermore DM, Woodford N. 2010. Emergence of a new antibiotic resistance mechanism in India, Pakistan, and the UK: a molecular, biological, and epidemiological study. Lancet Infect Dis 10:597–602. doi: 10.1016/S1473-3099(10)70143-2. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 24.Seema K, Ranjan Sen M, Upadhyay S, Bhattacharjee A. 2011. Dissemination of the New Delhi metallo-β-lactamase-1 (NDM-1) among Enterobacteriaceae in a tertiary referral hospital in north India. J Antimicrob Chemother 66:1646–1647. doi: 10.1093/jac/dkr180. [DOI] [PubMed] [Google Scholar]
  • 25.Rossi F. 2011. The challenges of antimicrobial resistance in Brazil. Clin Infect Dis 52:1138–1143. doi: 10.1093/cid/cir120. [DOI] [PubMed] [Google Scholar]
  • 26.Souli M, Kontopidou FV, Papadomichelakis E, Galani I, Armaganidis A, Giamarellou H. 2008. Clinical experience of serious infections caused by Enterobacteriaceae producing VIM-1 metallo-β-lactamase in a Greek university hospital. Clin Infect Dis 46:847–854. doi: 10.1086/528719. [DOI] [PubMed] [Google Scholar]
  • 27.Shevchenko OV, Mudrak DY, Skleenova EY, Kozyreva VK, Ilina EN, Ikryannikova LN, Alexandrova IA, Sidorenko SV, Edelstein MV. 2012. First detection of VIM-4 metallo-β-lactamase-producing Escherichia coli in Russia. Clin Microbiol Infect 18:E214–E217. doi: 10.1111/j.1469-0691.2012.03827.x. [DOI] [PubMed] [Google Scholar]
  • 28.Edelstein MV, Skleenova EN, Shevchenko OV, D'souza JW, Tapalski DV, Azizov IS, Sukhorukova MV, Pavlukov RA, Kozlov RA, Toleman MA, Walsh TR. 2013. Spread of extensively resistant VIM-2-positive ST235 Pseudomonas aeruginosa in Belarus, Kazakhstan, and Russia: a longitudinal epidemiological and clinical study. Lancet Infect Dis 13:867–876. doi: 10.1016/S1473-3099(13)70168-3. [DOI] [PubMed] [Google Scholar]
  • 29.Mendes RE, Mendoza M, Banga Singh KK, Castanheira M, Bell JM, Turnidge JD, Lin SSF, Jones RN. 2013. Regional resistance surveillance program results for 12 Asia-Pacific nations (2011). Antimicrob Agents Chemother 57:5721–5726. doi: 10.1128/AAC.01121-13. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 30.Biedenbach D, Bouchillon S, Hackel M, Hoban D, Kazmierczak K, Hawser S, Badal R. 2015. Dissemination of NDM metallo-β-lactamase genes among clinical isolates of Enterobacteriaceae collected during the SMART Global Suveillance Study from 2008 to 2012. Antimicrob Agents Chemother 59:826–830. doi: 10.1128/AAC.03938-14. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 31.Zhao W-H, Hu Z-Q. 2011. IMP-type metallo-β-lactamases in Gram-negative bacilli: distribution, phylogeny, and association with integrons. Crit Rev Microbiol 37:214–226. doi: 10.3109/1040841X.2011.559944. [DOI] [PubMed] [Google Scholar]
  • 32.Mantengoli E, Luzzaro F, Pecile P, Cecconi D, Cavallo A, Attala L, Bartoloni A, Rossolini GM. 2011. Escherichia coli ST131 producing extended spectrum β-lactamases plus VIM-1 carbapenemase: further narrowing of treatment options. Clin Infect Dis 52:690–691. doi: 10.1093/cid/ciq194. [DOI] [PubMed] [Google Scholar]
  • 33.Mushtaq S, Irfan S, Sarma JB, Doumith M, Pike R, Pitout J, Livermore DM, Woodford N. 2011. Phylogenetic diversity of Escherichia coli strains producing NDM-type carbapenemases. J Antimicrob Chemother 66:2002–2005. doi: 10.1093/jac/dkr226. [DOI] [PubMed] [Google Scholar]
  • 34.Hussain A, Ranjan A, Nandanwar N, Babbar A, Jadhav S, Ahmed N. 2014. Genotypic and phenotypic profiles of Escherichia coli isolates belonging to clinical sequence type 131 (ST131), clinical non-ST131, and fecal non-ST131 lineages from India. Antimicrob Agents Chemother 58:7240–7249. doi: 10.1128/AAC.03320-14. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 35.Wright LL, Turton JA, Livermore DM, Hopkins KL, Woodford N. 2015. Dominance of international ‘high-risk clones’ among metallo-β-lactamase-producing Pseudomonas aeruginosa in the UK. J Antimicrob Chemother 70:103–110. doi: 10.1093/jac/dku339. [DOI] [PubMed] [Google Scholar]
  • 36.Correa A, Montealegre MC, Mojica MF, Maya JJ, Rojas LJ, De La Cadena EP, Ruiz SJ, Recalde M, Rosso F, Quinn JP, Villegas MV. 2012. First report of a Pseudomonas aeruginosa isolate coharboring KPC and VIM carbapenemases. Antimicrob Agents Chemother 56:5422–5423. doi: 10.1128/AAC.00695-12. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 37.Vanegas JM, Cienfuegos AV, Ocampo AM, Lopez L, del Corral H, Roncancio G, Sierra P, Echeverri-Toro L, Ospina S, Maldonado N, Robledo C, Restrepo A, Jimenez JN. 2014. Similar frequencies of Pseudomonas aeruginosa isolates producing KPC and VIM carbapenemases in diverse genetic clones at tertiary-care hospitals in Medellin, Colombia. J Clin Microbiol 52:3978–3986. doi: 10.1128/JCM.01879-14. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 38.Giakkoupi P, Pappa O, Polemis M, Vatapoulos AC, Miriagou V, Zioga A, Papagiannitsis CC, Tsouvelekis LS. 2009. Emerging Klebsiella pneumoniae isolates coproducing KPC-2 and VIM-1 carbapenemases. Antimicrob Agents Chemother 53:4048–4050. doi: 10.1128/AAC.00690-09. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 39.Papagiannitsis CC, Giakkoupi P, Vatapoulos AC, Tryfinopoulou K, Miriagou V, Tsouvelekis LS. 2010. Emergence of Klebsiella pneumoniae of a novel sequence type (ST383) producing VIM-4, KPC-2 and CMY-4 β-lactamases. J Antimicrob Agents 36:573–574. doi: 10.1016/j.ijantimicag.2010.07.018. [DOI] [PubMed] [Google Scholar]
  • 40.Pournaras S, Poulou A, Voulgari E, Vrioni G, Kristo I, Tsakris A. 2010. Detection of the new metallo-β-lactamase VIM-19 along with KPC-2, CMY-2 and CTX-M-15 in Klebsiella pneumoniae. J Antimicrob Chemother 65:1604–1607. doi: 10.1093/jac/dkq190. [DOI] [PubMed] [Google Scholar]
  • 41.Steinmann J, Kaase M, Gatermann S, Popp W, Steinmann E, Damman M, Paul A, Saner F, Buer J, Rath PM. 2011. Outbreak due to a Klebsiella pneumoniae strain harbouring KPC-2 and VIM-1 in a German university hospital, July 2010 to January 2011. Euro Surveill 16:pii=19944. [PubMed] [Google Scholar]
  • 42.Markovska R, Schneider I, Stoeva T, Bojkova K, Boyanova L, Bauernfeind A, Mitov I. 2013. First identification of KPC-2 and VIM-1 producing Klebsiella pneumoniae in Bulgaria. Diagn Microbiol Infect Dis 77:252–253. doi: 10.1016/j.diagmicrobio.2013.07.019. [DOI] [PubMed] [Google Scholar]
  • 43.Rojas LJ, Mojica MF, Blanco VM, Correa A, Montealegre MC, De La Cadena E, Maya JJ, Camargo RD, Quinn JP, Villegas MV. 2013. Emergence of Klebsiella pneumoniae coharboring KPC and VIM carbapenemases in Colombia. Antimicrob Agents Chemother 57:1101–1102. doi: 10.1128/AAC.01666-12. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 44.Ben Nasr A, Decre D, Compain F, Genel N, Barguellil F, Arlet G. 2013. Emergence of NDM-1 in association with OXA-48 in Klebsiella pneumoniae from Tunisia. Antimicrob Agents Chemother 57:4089–4090. doi: 10.1128/AAC.00536-13. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 45.Seiffert SN, Marschall J, Perreten V, Carattoli A, Furrer H, Endimiani A. 2014. Emergence of Klebsiella pneumoniae co-producing NDM-1, OXA-48, CTX-M-15, CMY-16, QnrA and ArmA in Switzerland. Int J Antimicrob Agents 44:260–262. doi: 10.1016/j.ijantimicag.2014.05.008. [DOI] [PubMed] [Google Scholar]
  • 46.Kilic A, Baysallar M. 2015. The first Klebsiella pneumoniae isolate co-producing OXA-48 and NDM-1 in Turkey. Ann Lab Med 35:382–383. doi: 10.3343/alm.2015.35.3.382. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 47.Doi Y, O'Hara JA, Lando JF, Querry AM, Townsend BM, Pasculle AW, Muto CA. 2014. Co-production of NDM-1 and OXA-232 by Klebsiella pneumoniae. Emerg Infect Dis 20:163–164. doi: 10.3201/eid2001.130904. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 48.Bogaerts P, Bebrone C, Huang T-D, Bouchahrouf W, DeGheldre Y, Deplano A, Hoffmann K, Glupczynski Y. 2012. Detection and characterization of VIM-31, a new variant of VIM-2 with Tyr224His and His252Arg mutations, in a clinical isolate of Enterobacter cloacae. Antimicrob Agents Chemother 56:3283–3287. doi: 10.1128/AAC.06249-11. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 49.Poirel L, Potron A, Nordmann P. 2012. OXA-48-like carbapenemases: the phantom menace. J Antimicrob Chemother 67:1597–1606. doi: 10.1093/jac/dks121. [DOI] [PubMed] [Google Scholar]
  • 50.Sonnevend A, Ghazawi A, Yahfoufi N, Al-Baloushi A, Hashmey R, Mathew M, Tariq WZ, Pal T. 2012. VIM-4 carbapenemase-producing Enterobacter cloacae in the United Arab Emirates. Clin Microbiol Infect 18:E494–E496. doi: 10.1111/1469-0691.12051. [DOI] [PubMed] [Google Scholar]
  • 51.Livermore DM. 2005. Tigecycline: what is it, and where should it be used? J Antimicrob Chemother 56:611–614. doi: 10.1093/jac/dki291. [DOI] [PubMed] [Google Scholar]
  • 52.Olaitan AO, Morand S, Rolain J-M. 2014. Mechanisms of polymyxin resistance: acquired and intrinsic resistance in bacteria. Front Microbiol 5:643. doi.10.3389/fmicb.2014.00643. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 53.Poirel L, Dortet L, Bernabeu S, Nordmann P. 2011. Genetic features of blaNDM-1-positive Enterobacteriaceae. Antimicrob Agents Chemother 55:5403–5407. doi: 10.1128/AAC.00585-11. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 54.Pfizer, Inc. 2010. Tygacil®. Tigecycline FDA prescribing information. Pfizer, Inc., Collegeville, PA. [Google Scholar]
  • 55.European Committee on Antimicrobial Susceptibility Testing. 2015. Breakpoint tables for interpretation of MICs and zone diameters, version 5.0. http://www.eucast.org/fileadmin/src/media/PDFs/EUCAST_files/Breakpoint_tables/v_5.0_Breakpoint_Table_01.pdf.

Articles from Antimicrobial Agents and Chemotherapy are provided here courtesy of American Society for Microbiology (ASM)

RESOURCES