ABSTRACT
A total of 1,925 Corynebacterium isolates were tested for antimicrobial susceptibility at the Mayo Clinic Microbiology laboratory (Rochester, Minnesota) from January 2012 to March 2023, with C. striatum (35.6%) and C. amycolatum (24.4%) identified as the predominant species. Species known to potentially carry diphtheria toxin were excluded. Common sources of isolation included skin and soft tissue (56.8%), bone and/or native joint synovial fluid (14.2%), urine (13.1%), sputum (6.1%), and blood (5.9%). For penicillin, susceptibility decreased from 47.5% (58 of 122) in 2012 to 20.6% (14 of 68) in 2023. Isolates also showed a decrease in susceptibility to erythromycin from 22.4% (26 of 116) in 2012 to 13.2% (9 of 68) in 2023. Susceptibility to trimethoprim-sulfamethoxazole averaged around 50% throughout the period. Notably, linezolid and vancomycin were universally effective in vitro against all species. The highest susceptibility rates among tested oral agents were to linezolid and doxycycline for non-C. striatum species. Daptomycin minimal inhibitory concentrations (MICs) of >256 µg/mL were observed for one C. amycolatum isolate, one C. tuberculostearicum isolate, and for seven C. striatum isolates, all from patients with prior daptomycin exposure. Daptomycin MICs of 2 µg/mL (nonsusceptible) were observed in one C. striatum isolate recovered from a daptomycin-naïve patient and in six C. jeikeium isolates, from both daptomycin-exposed and non-exposed patients. Significant variation in susceptibility profiles across different Corynebacterium species underscores the importance of performing antimicrobial susceptibility testing to guide effective treatment. Moreover, multidrug resistance observed in C. striatum poses substantial therapeutic challenges especially in patients requiring prolonged or chronic antibiotic suppression.
KEYWORDS: Corynebacterium, susceptibility, resistance, antimicrobial, antibiotic
INTRODUCTION
Non-diphtheriae Corynebacterium species are Gram-positive catalase-positive rod-shaped bacteria that are ubiquitous in the environment and are commensal organisms of human mucosal surfaces (1). However, non-diphtheriae Corynebacterium species have emerged as clinically significant opportunistic pathogens, particularly in immunocompromised individuals and those with indwelling medical devices, causing a wide spectrum of clinical infections (1–5). Furthermore, management of infection is often complicated by the resistance of non-diphtheriae Corynebacterium species to multiple classes of antibiotics, impairing the selection of effective empiric and definitive therapy (6). In this context, with the increasing recognition of the clinical significance of these microorganisms, a comprehensive understanding of their antimicrobial susceptibility profiles to guide effective therapeutic strategies is needed and, in comparison to more routine culprit pathogens, data on species-specific susceptibility patterns for non-diphtheriae Corynebacteria are also limited (7–10).
Herein, we review antimicrobial susceptibility patterns of non-diphtheriae Corynebacterium isolates tested at the Clinical Microbiology laboratory at Mayo Clinic in Rochester, Minnesota, a tertiary medical center with a reference laboratory, over an 11-year period (January 2012 to March 2023) and summarize species-specific resistance profiles that could be used by clinicians to guide therapeutic decisions. Species known to potentially carry the diphtheria toxin were not included in this study.
MATERIALS AND METHODS
Study design
Following Mayo Clinic Institutional Review Board review and approval (#23-001149), we retrospectively analyzed available laboratory data from non-diphtheriae Corynebacterium isolates submitted to the Clinical Microbiology laboratory at Mayo Clinic in Rochester, including culture collection date, specimen source, identification, and antimicrobial susceptibility testing (AST) results from patients cared for at Mayo Clinic in Rochester as well as isolates referred to Mayo Clinic Laboratories (MCL) by external clients from January 2012 to March 2023. Non-diphtheriae Corynebacterium clinical isolates were identified following a thorough review of microbiology laboratory culture records from internal specimens and external client testing. Retrospective data were reviewed. Duplicate results pertaining to the same tested specimen (i.e., sharing the same laboratory order number) were excluded. Additionally, susceptibility testing results were excluded if the same organism was isolated from the same source in the patient within a 7-day period. Patients were also excluded if they lacked research authorization per Minnesota statute.
Microbial identification
The identification of Corynebacterium species was achieved using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS; Bruker Daltonics, Billerica, MA, Mayo Clinic Custom MALDI-TOF MS Library) using on-plate extraction with library updates over time and, when necessary, in situations where MALDI-TOF MS was inconclusive, additional assessment of morphological and biochemical traits and/or partial 16S ribosomal ribonucleic acid (rRNA) gene sequencing. Since 2012, our facility has routinely employed MALDI-TOF MS for organism identification. Before 2012, Corynebacterium species were identified primarily through biochemical methods. It should be noted that while MALDI-TOF MS is highly effective at identifying closely related species commonly encountered in clinical settings, a “slash call” may be reported when species are similar and differentiation is not possible. This was the case for Corynebacterium propinquum/pseudodiptheriticum and C. aurimucosum/minutissimum where differentiation was beyond the capacity of MALDI-TOF MS resulting in this reporting species.
Antimicrobial susceptibility testing
Phenotypic antimicrobial susceptibility of the isolates was performed using the Clinical and Laboratory Standards Institute (CLSI) reference agar dilution method, and the results were interpreted following CLSI standards (11). Agar dilution was employed for all agents using Mueller-Hinton agar with 5% lysed horse blood, with the exception of daptomycin. Lipid supplementation was not used, as it is not recommended by CLSI. Plates were incubated at 35°C with 5–7% CO2 for 20–24 hours. At 24 hours, results were recorded for the non-beta-lactam antimicrobials and when beta-lactam results were resistant at that time. Plates were reincubated if results of beta-lactam antimicrobials were susceptible at 24 hours, and final results for those beta-lactam antimicrobials were recorded at 48 hours. AST results were recorded following CLSI recommendations and when growth was adequate. Daptomycin testing was performed using E-test (bioMérieux, Durham, NC). While our laboratory routinely uses agar dilution (and E-test for daptomycin), the CLSI reference standard for Corynebacterium AST is broth microdilution. Routine AST was performed for penicillin, ceftriaxone, meropenem, and vancomycin for isolates from all sources, including blood. Other antimicrobial agents with available CLSI breakpoints were tested at the request of the client or primary treatment team. The CLSI breakpoints for penicillin were revised in 2015 from ≤1 µg/mL (susceptible), 2 µg/mL (intermediate), and ≥4 µg/mL (resistant) to ≤0.12 µg/mL (susceptible), 0.25–2 µg/mL (intermediate), and ≥4 µg/mL (resistant) (11). Similarly, meropenem breakpoint were updated from ≤4 µg/mL (susceptible), 8 µg/mL (intermediate), and ≥16 µg/mL (resistant) to ≤0.25 µg/mL (susceptible), 0.5 µg/mL (intermediate), and ≥1 µg/mL (resistant) (11). These breakpoint changes were implemented in our laboratory in December 2016.
Statistical analysis
Descriptive statistics in this series are described as a number (percentage) for categorical variables. All analyses were performed using R version 4.2.2 (R Foundation for Statistical Computing, Vienna, Austria).
RESULTS
A total of 1,925 non-diphtheriae Corynebacterium isolates were tested in our laboratory from January 2012 to March 2023. These comprised 18 Corynebacterium species, the majority being C. striatum (n = 686, 35.6%), followed by C. amycolatum (n = 471, 24.5%), C. propinquum/pseudodiphtheriticum (n = 189, 9.8%), C. jeikeium (n = 96, 5.0%), and C. aurimucosum/minutissimum (n = 92, 4.8%), among others (Table 1). There was an upward trend in the overall number of non-diphtheriae Corynebacterium isolates identified from 2012 to 2022, including C. striatum and C. amycolatum, but not C. jeikeium or C. propinquum/pseudodiphtheriticum (Fig. S1).
TABLE 1.
Antimicrobial susceptibility results by species,a
| Organism | No. (%) of strains susceptible to: | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Linezolid | Vancomycin | Daptomycin | Doxycycline | TMP-SMX | Cefepime | Ceftriaxone | Meropenem | Penicillin | Ciprofloxacin | |
| C. striatum (686) | 169/169 (100%) | 683/684 (99.9%) | 206/214 (96.3%) | 75/309 (24.3%) | 47/669 (7.0%) | 59/659 (9.0%) | 7/684 (1.0%) | 210/684 (30.7%) | 50/684 (7.3%) | 10/214 (4.7%) |
| C. amycolatum (471) | 106/106 (100%) | 471/471 (100.0%) | 87/88 (98.9%) | 192/229 (83.8%) | 368/466 (79.0%) | 314/454 (69.2%) | 238/471 (50.5%) | 129/471 (27.4%) | 132/471 (28.0%) | 40/150 (26.7%) |
| C. propinquum/ pseudodiphtheriticum (189) | 27/27 (100%) | 188/189 (99.5%) | 6/6 (100.0%) | 97/97 (100.0%) | 135/185 (73.0%) | 183/185 (98.9%) | 187/189 (99.0%) | 186/189 (98.4%) | 185/189 (97.9%) | 48/57 (84.2%) |
| C. jeikeium (96) | 17/17 (100%) | 96/96 (100.0%) | 18/24 (75.0%) | 34/37 (91.9%) | 19/93 (20.4%) | 15/93 (16.1%) | 3/96 (3.1%) | 14/96 (14.6%) | 1/96 (1.0%) | 4/21 (19.0%) |
| C. aurimucosum/ minutissimum (92) | 24/24 (100%) | 92/92 (100.0%) | 27/27 (100.0%) | 58/61 (95.1%) | 74/92 (80.4%) | 92/92 (100.0%) | 32/92 (34.8%) | 87/92 (94.6%) | 26/92 (28.3%) | 22/40 (55.0%) |
| C. tuberculostearicum (58) | 24/24 (100%) | 56/56 (100.0%) | 15/16 (93.8%) | 30/40 (75.0%) | 28/52 (53.8%) | 20/49 (40.8%) | 23/56 (41.1%) | 27/56 (48.2%) | 19/56 (33.9%) | 15/37 (40.5%) |
| C. accolens (57) | 17/17 (100%) | 57/57 (100.0%) | 11/11 (100.0%) | 39/39 (100.0%) | 54/57 (94.7%) | 56/56 (100.0%) | 56/57 (98.2%) | 57/57 (100.0%) | 52/57 (91.2%) | 29/31 (93.5%) |
| C. urealyticum (53) | 10/10 (100%) | 53/53 (100.0%) | 1/1 (100.0%) | 20/20 (100.0%) | 9/53 (17.0%) | 7/53 (13.2%) | 6/53 (11.3%) | 6/53 (11.3%) | 5/53 (9.4%) | 1/17 (5.9%) |
| C. simulans (42) | 14/14 (100%) | 42/42 (100%) | 12/12 (100.0%) | 26/28 (92.9%) | 38/40 (95.0%) | 36/39 (92.3%) | 5/42 (11.9%) | 38/42 (90.5%) | 13/42 (31.0%) | 16/20 (80.0%) |
| C. pseudogenitalium (38) | 16/16 (100%) | 37/37 (100.0%) | 5/5 (100.0%) | 17/29 (58.6%) | 25/37 (67.6%) | 27/37 (73.0%) | 28/37 (75.7%) | 24/37 (64.9%) | 11/37 (29.7%) | 7/24 (29.2%) |
| C. coyleae (31) | 10/10 (100%) | 29/30 (96.7%) | 8/8 (100.0%) | 17/19 (89.5%) | 16/30 (53.3%) | 26/30 (86.7%) | 6/30 (20.0%) | 28/30 (93.3%) | 5/30 (16.7%) | 5/9 (55.6%) |
| C. glucuronolyticum (21) | 2/2 (100%) | 21/21 (100.0%) | 6/8 (75.0%) | 15/20 (75.0%) | 20/20 (100.0%) | 5/21 (23.8%) | 18/21 (85.7%) | 18/21 (85.7%) | 1/4 (25.0%) | |
| C. kroppenstedtii (20) | 10/10 (100%) | 20/20 (100.0%) | 2/2 (100.0%) | 11/12 (91.7%) | 17/19 (89.5%) | 19/19 (100.0%) | 11/20 (55.0%) | 17/20 (85.0%) | 6/20 (30.0%) | 8/10 (80.0%) |
| C. riegelii (19) | 1/1 (100%) | 19/19 (100.0%) | 1/1 (100.0%) | 4/4 (100.0%) | 13/19 (68.4%) | 19/19 (100.0%) | 12/19 (63.2%) | 18/19 (94.7%) | 14/19 (73.7%) | 2/2 (100.0%) |
| C. (formerly Turicella) otitidis (17) | 4/4 (100%) | 17/17 (100.0%) | 13/13 (100.0%) | 16/17 (94.1%) | 17/17 (100.0%) | 16/17 (94.1%) | 17/17 (100.0%) | 17/17 (100.0%) | 3/9 (33.3%) | |
| C. resistens (15) | 5/5 (100%) | 14/15 (93.3%) | 2/2 (100.0%) | 4/5 (80.0%) | 6/14 (42.9%) | 0/14 (0.0%) | 0/15 (0.0%) | 0/15 (0.0%) | 0/15 (0.0%) | 3/3 (100.0%) |
| C. afermentans (11) | 1/1 (100%) | 11/11 (100.0%) | 3/3 (100.0%) | 9/9 (100.0%) | 9/11 (81.8%) | 8/11 (72.7%) | 5/11 (45.5%) | 9/11 (81.8%) | 0/11 (0.0%) | 4/5 (80.0%) |
| C. macginleyi (9) | 3/3 (100%) | 9/9 (100.0%) | 1/1 (100.0%) | 8/8 (100.0%) | 9/9 (100.0%) | 9/9 (100.0%) | 9/9 (100.0%) | 9/9 (100.0%) | 9/9 (100.0%) | 4/4 (100.0%) |
| All isolates (1925) | 460/460 (100%) |
1915/1919 (99.8%) | 405/421 (96.2%) |
660/967 (68.3%) |
898/1,883 (47.7%) |
927/1,856 (50.0%) |
649/1,919 (33.8%) |
894/1,919 (46.6%) |
563/1,919 (29.3%) |
222/657 (33.8%) |
Minocycline susceptibility testing was performed on 27 C. striatum isolates, of which 16 (59.2%) displayed MICs ≤4 µg/mL, 9 (33.3%) displayed MICs of 8 µg/mL, and 2 (7.5%) displayed MICs >8 µg/mL. The colors represent the percentage of measured susceptibility at the time of testing based on CLSI breakpoints: white indicates >90% susceptibility, light grey indicates 50–90% susceptibility, and dark grey indicates <50% susceptibility. Black indicates no available data for the corresponding isolate and antimicrobial agent. TMP-SMX, trimethoprim-sulfamethoxazole.
Skin and soft tissue accounted for the largest number of originating sources for isolates in this study followed by bone and/or native joint synovial fluids (n = 274, 14.2%), urine (n = 252, 13.1%), sputum (n = 117, 6.1%), eye swabs (n = 64, 3.3%), peripheral blood (n = 62, 3.2%), ear swabs (n = 57, 3.0%), and central venous catheters (n = 52, 2.7%) (from peripheral blood and central venous catheters [n = 114, 5.9%]) (Fig. 1). When stratifying the source of isolation by organism (Table S1), C. striatum was the predominant organism isolated from skin (n = 358, 39.8%) and bone and/or native joints (n = 167, 60.9%), followed by C. amycolatum (n = 252, 28.0% and n = 45, 16.4%, respectively). C. striatum was also the most frequently isolated organism from orthopedic hardware specimens (n = 15, 48.4%), followed by C. tuberculostearicum (n = 5, 16.1%) and C. amycolatum (n = 5, 16.1%). C. striatum was the predominant species isolated from both peripheral and central venous blood (n = 54, 50.5%), followed by C. jeikeium (n = 20, 18.7%) and C. amycolatum (n = 16, 15.0%). Sputum was the most common source noted for C. propinquum/pseudodiphtheriticum (n = 97, 79.5%) isolates in this study, while urine was the most common source noted for C. amycolatum (n = 68, 26.9%), C. urealyticum (n = 53, 21.0%), and C. pseudogenitalium (n = 41, 13.9%). Finally, C. amycolatum was the predominant organism isolated from cardiac devices (n = 8, 42.1%) submitted for culture, and C. striatum was only associated with one (n = 1, 5.2%) case specimen from this source.
Fig 1.
Specimen sources associated with various Corynebacterium species. CNS, central nervous system.
Antimicrobial susceptibility profiles of tested isolates are shown in Table 1. When linezolid was tested (n = 460), isolates were universally susceptible (100%), and 1,915 of 1,919 (99.8%) isolates were susceptible to vancomycin. When considering orally-formulated antibiotics only, non-C. striatum isolates displayed the highest susceptibility rates to linezolid (291 of 291, 100%) and doxycycline (585 of 658, 88.9%). Temporal analysis of oral antibiotics over the study period from 2012 to 2023 revealed varied trends in susceptibility rates (Fig. 2). For penicillin, susceptibility decreased from 47.5% (58 of 122) in 2012 to 20.6% (14 of 68) in 2023. Isolates also showed a decrease in susceptibility to erythromycin from 22.4% (26 of 116) in 2012 to 13.2% (9 of 68) in 2023. In contrast, the susceptibility rate to trimethoprim-sulfamethoxazole (TMP-SMX) was relatively stable, averaging 50% throughout the period. The susceptibility trend for clindamycin was challenging to interpret due to the limited number of tested isolates in earlier years. However, a notable observation was the low susceptibility rate of 7.3% (25 of 343) from 2021 to 2023. It is worth noting that, despite displaying low susceptibility rates to penicillin (30%), C. kroppenstedtii—a species associated with granulomatous mastitis—exhibited high susceptibility rates to doxycycline (91.7%) and TMP-SMX (89.5%).
Fig 2.
Antibiotic susceptibility patterns over time for select oral antibiotics. TMP-SMX, trimethoprim-sulfamethoxazole.
Daptomycin MICs indicating non-susceptibility (MIC ≥2 µg/mL) were observed in 3.7% (8 of 214) of C. striatum isolates, 1.1% (1 of 88) of C. amycolatum, 6.2% (1 of 16) of C. tuberculostearicum, and 25% (6 of 24) of C. jeikeium isolates (MIC ≥2 µg/mL). Notably, daptomycin MICs of >256 µg/mL were observed in C. amycolatum isolates from skin and soft tissue and C. tuberculostearicum isolates from blood, in patients with a history of exposure to daptomycin. Among the C. striatum isolates, seven with MICs >256 µg/mL were from patients previously treated with daptomycin. These included two isolates from bone and native joints, four from blood, and one from skin and soft tissue. Conversely, a MIC of 2 µg/mL was observed for one C. striatum isolated from the skin of a daptomycin-naïve patient and all six non-susceptible C. jeikeium isolates in patients irrespective of prior daptomycin exposure. These C. jeikeium isolates included three from bone and native joints, one from blood, one from a drain, and one from skin and soft tissue.
The lowest susceptibility rates of C. striatum were to penicillin (7.3%, 50 of 684), ciprofloxacin (4.7%, 10 of 214), doxycycline (24.3%, 75 of 309), and TMP-SMX (7.0%, 47 of 669), with linezolid being the only oral option for which isolates demonstrated 100% (169 of 169) susceptibility. Notably, minocycline AST was performed on 27 C. striatum isolates (no clinical breakpoints per CLSI), for which 59.2% (n = 16) displayed a MIC ≤4 µg/mL. Moreover, both minocycline and doxycycline AST were performed on nine C. striatum isolates, among which three were resistant to doxycycline (MIC ≥16 µg/mL) but displayed a MIC ≤4 µg/mL to minocycline, and two were intermediate to doxycycline (MIC = 8 µg/mL) but with a measured MIC ≤4 µg/mL to minocycline.
DISCUSSION
This study describes our institutional experience with organism identification and AST of non-diphtheriae Corynebacterium isolates in our large reference clinical microbiology laboratory over an 11-year period with the goal of providing clinicians with contemporary antimicrobial susceptibility data to better guide empiric and definitive therapy choices for patients with infection attributable to these organisms. Further, we sought to elucidate temporal trends and identify patterns of antimicrobial resistance amongst these Corynebacterium isolates.
Overall, we observed an increase in the number of non-diphtheriae Corynebacteria isolates recovered from a diverse array of specimen sources over the study period. The increased recovery of these species may be partially attributed to the use of MALDI-TOF, a rapid and definitive identification method throughout the entire study period. Skin and soft tissue, followed by bone and/or native joint synovial fluids, urine, sputum, and blood (peripheral and central venous catheter), were the most common sources from which species were recovered. C. striatum was the most frequently observed species overall in our cohort irrespective of source and noted to be the most common species isolated from 7 of 17 total sources over this timeframe, congruent with published laboratory data (8, 12). While orthopedic hardware, cardiac devices, endovascular sources, central nervous system (CNS) hardware, and prostheses were specimens less commonly associated with Corynebacterium spp., recovery from these sources aligns with literature describing non-diphtheriae Corynebacterium species as an increasingly recognized causative pathogen for clinical infection in immunocompromised hosts as well as the culprit of device-related and hardware infection (12–16).
Corynebacterium isolates in this study were universally susceptible to linezolid and 99.8% of tested isolates were susceptible to vancomycin, consistent with reported literature (7, 8, 10, 12, 17, 18). This suggests that these agents may provide effective empirical antimicrobial coverage for Corynebacterium spp. until species-level identification and dedicated AST are available. Beyond this trend, susceptibility patterns were variable across species. Temporal trend analysis of antimicrobial susceptibility among Corynebacterium spp. revealed decreases in AST rates to oral antibiotics over time, including penicillin, clindamycin, and erythromycin. It should be noted that CLSI breakpoints for penicillin and meropenem changed in 2015 with the publication of new CLSI guidance and were implemented in our reference microbiology laboratory in December 2016 (11). This adjustment may have contributed to an observed increased in vitro resistance over time during the study period (Fig. 2).
Although C. striatum was the most frequently recovered Corynebacterium spp., oral antimicrobial options for this species are severely limited, posing significant therapeutic challenges. Apart from linezolid, which may require careful monitoring, 24% of C. striatum isolates displayed susceptibility to doxycycline. Low susceptibility rates of C. striatum to oral antimicrobial agents have also been described in previous cohorts, including 0–0.1% susceptibility to penicillin, 14.6–21% susceptibility to erythromycin, 4.6–19% susceptibility to ciprofloxacin, and 5.4–13.3% susceptibility to clindamycin (8, 18), underscoring the importance of species-level identification and AST to further tailor antimicrobial therapy.
Notably, daptomycin MICs of 2 µg/mL (nonsusceptible) were observed in 25% of C. jeikeium isolates, independent of prior daptomycin exposure of the patient. Although only 3.7% of C. striatum tested non-susceptible, most demonstrated a MIC >256 µg/mL, aligning with prior daptomycin exposure. The rapid emergence of daptomycin resistance in Corynebacterium isolates following daptomycin exposure is well recognized, and clinicians should be vigilant when using daptomycin particularly for invasive infections due to C. jeikeium (3) and C. striatum associated with high bacterial burden such as left-ventricular assist device infections (19–21) or infective endocarditis (22). The mechanism of daptomycin resistance in Corynebacterium spp. remains unclear; however, unlike that observed with daptomycin-nonsusceptible S. aureus (23), an increase in MICs to vancomycin has not been reported for daptomycin-nonsusceptible Corynebacterium spp., suggesting a novel mechanism of resistance (3, 19, 20, 22).
Strengths of this study include the large volume of clinical isolates with measured MICs. To our knowledge, this is the largest contemporary data set of non-diphtheriae Corynebacterium species AST available and includes patients internal to Mayo Clinic practice as well as isolates referred by clients worldwide. However, it should be acknowledged that this study was conducted retrospectively, and existing sources of bias and confounding may be difficult to eliminate. Moreover, we could not assess the clinical significance of Corynebacterium spp. isolates in our cohort, nor could we review the antibiotic therapy and clinical outcomes of patients with proven infections. Finally, source identification of isolates submitted by clients was occasionally vague and difficult to classify.
In conclusion, significant variation in susceptibility profiles exists between different species of Corynebacterium. High rates of resistance among the most common species such as C. striatum are associated with therapeutic challenges. Overall, our study outlines antimicrobial susceptibility patterns observed from a large cohort of clinical isolates from our internal practice and from external clients, contributing to an area in the literature where data are scant. Potential applications of this work include the use of this in vitro data as a reference for clinicians to better inform the selection of empirical antimicrobial therapy until microbiologic laboratory workup and testing have been successfully completed.
Contributor Information
Madiha Fida, Email: fida.madiha@mayo.edu.
Jennifer Dien Bard, Children's Hospital Los Angeles, Los Angeles, California, USA.
DATA AVAILABILITY
Raw data are available through the corresponding author upon reasonable request.
ETHICS APPROVAL
The Mayo Clinic Institutional Review Board reviewed the study protocol and granted it an exempt status (#23-001149) on 23 February 2023.
SUPPLEMENTAL MATERIAL
The following material is available online at https://doi.org/10.1128/jcm.01199-24.
Yearly distribution and trends of various Corynebacterium species isolates from 2012 to 2023. The bar chart represents the total number of isolates per year, with individual counts labeled above each bar. The year 2023 was excluded from trend line due to incomplete data.
Originating specimen sources of Corynebacterium species.CVC, central venous catheter; CNS, central nervous system.
ASM does not own the copyrights to Supplemental Material that may be linked to, or accessed through, an article. The authors have granted ASM a non-exclusive, world-wide license to publish the Supplemental Material files. Please contact the corresponding author directly for reuse.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Yearly distribution and trends of various Corynebacterium species isolates from 2012 to 2023. The bar chart represents the total number of isolates per year, with individual counts labeled above each bar. The year 2023 was excluded from trend line due to incomplete data.
Originating specimen sources of Corynebacterium species.CVC, central venous catheter; CNS, central nervous system.
Data Availability Statement
Raw data are available through the corresponding author upon reasonable request.