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. 2021 Nov 25;12:738784. doi: 10.3389/fmicb.2021.738784

TABLE 2.

Phenotypic characterization of XDR Salmonella isolates recovered from poultry and human origins.

Isolate no. Isolate code Serovar Source Antimicrobial resistance patterna MAR index MIC (μg/ml)b
Efflux Pump activity
MIC (μg/ml)
CIP TIG MCEtBr (μg/ml) Indexc CIP + CCCP TIG + CCCP
1 H1 Typhimurium Human stool AM, AMC, SAM, CZ, CXM, CRO, FEB, FOX, IPM, TOB, NA, CIP, TE, TIG, FOS, C, SXT, ATM, CT 0.79 16 4 1 3 4 0.5
2 C1 Typhimurium Chicken muscle AMC, SAM, CZ, CXM, CRO, FEB, FOX, CN, TOB, NA, CIP, TE, TIG, FOS, C, SXT, ATM, CT 0.75 32 4 1 3 16 1
3 D1 Untypable Duck cloacal swab AM, AMC, SAM, CZ, CXM, CRO, FEB, FOX, IPM, TOB, NA, CIP, TE, TIG, FOS, C, SXT, CT 0.75 64 16 2 7 16 2
4 C2 Magherafelt Chicken liver AM, AMC, SAM, CZ, CXM, CRO, FEB, FOX, TOB, NA, CIP, TE, TIG, FOS, C, SXT, CT 0.71 16 4 1 3 2 0.5
5 C3 Typhimurium Chicken spleen AM, AMC, SAM, CZ, CXM, CRO, FEB, FOX, CN, TOB, NA, CIP, TE, FOS, C, ATM, CT 0.71 4 2 0.5 1 0.5 2
6 C4 Takoradi Chicken cecum AM, AMC, SAM, CZ, CXM, CRO, FEB, FOX, CN, TOB, NA, CIP, TE, TIG, FOS, C, SXT, CT 0.75 32 8 1.5 5 8 2
7 C5 Labadi Chicken gall bladder AM, AMC, SAM, CZ, CXM, CRO, FEB, FOX, CN, TOB, NA, CIP, TE, TIG, FOS, C, SXT, ATM 0.75 64 16 2.5 9 8 1
8 C6 Typhimurium Chicken liver AM, AMC, SAM, CZ, CXM, CRO, FEB, FOX, CN, AK, NA, CIP, TE, TIG, FOS, C, SXT, ATM 0.75 2 4 1 3 0.5 2
9 Q1 Jedburgh Quail dropping AM, AMC, SAM, CZ, CXM, CRO, FEB, FOX, TOB, NA, CIP, TE, TIG, FOS, C, SXT, ATM, CT 0.75 64 8 1.5 5 8 1
10 Q2 Alfort Quail liver AM, AMC, SAM, CZ, FEB, FOX, IPM, TOB, NA, CIP, TE, TIG, FOS, C, SXT, ATM, CT 0.71 64 16 2 7 16 2
11 C7 Typhimurium Chicken muscle AM, AMC, CZ, CXM, CRO, FEB, FOX, CN, TOB, NA, CIP, TE, TIG, FOS, C, SXT, ATM, CT 0.75 32 8 1.5 5 4 1
12 C8 Typhimurium Chicken spleen AM, AMC, CZ, CXM, FEB, FOX, IPM, TOB, NA, CIP, TE, TIG, FOS, SXT, ATM, CT 0.67 16 16 2 7 8 2
13 D2 Untypable Duck muscle AM, AMC, SAM, CZ, FEB, FOX, IPM, ETP, NA, CIP, TE, TIG, FOS, C, SXT, ATM, CT 0.71 8 4 1 3 2 1
14 C9 Blegdam Chicken muscle AMC, CZ, CXM, CRO, FEB, FOX, CN, NA, CIP, TE, TIG, FOS, C, SXT, ATM, CT 0.67 2 4 0.5 1 0.25 0.5
15 C10 Infantis Chicken liver AMC, CZ, CXM, CRO, FOX, IPM, CN, TOB, NA, CIP, TE, TIG, FOS, C, SXT, CT 0.67 2 4 0.5 1 2 2
16 C11 Enteritidis Chicken egg yolk AMC, CZ, CXM, CRO, FEB, FOX, AK, NA, CIP, TE, TIG, FOS, C, SXT, ATM, CT 0.67 2 4 0.5 1 0.5 1
17 H2 Typhimurium Human stool AM, AMC, CZ, CXM, CRO, FEB, FOX, AK, NA, CIP, TIG, FOS, C, SXT, ATM, CT 0.67 16 8 1.5 5 4 2
18 H3 Paratyphi C Human stool AM, AMC, SAM, CZ, CXM, CRO, FEB, FOX, CN, TOB, AK, NA, CIP, TE, TIG, FOS, C, SXT, ATM, CT 0.83 2 4 0.5 1 2 4
19 H4 Typhimurium Human stool AM, AMC, CZ, CXM, CRO, FEB, FOX, CN, TOB, AK, NA, CIP, TE, FOS, C, SXT, ATM, CT 0.75 4 0.5 0.5 1 2 0.5
20 C12 Typhimurium Chicken muscle AMC, SAM, CZ, FEB, FOX, CN, TOB, NA, CIP, TE, TIG, FOS, C, SXT, ATM, CT 0.67 2 4 1 3 0.5 2
21 C13 Bardo Chicken liver AM, AMC, CZ, CXM, CRO, FEB, FOX, IPM, ETP, MEM, DOR, AK, NA, CIP, TE, TIG, FOS, C, SXT, ATM, CT 0.88 128 32 2.5 9 32 2
22 C14 Sandiego Chicken cecum AM, AMC, SAM, CZ, CXM, CRO, FEB, FOX, CN, TOB, NA, CIP, TE, TIG, FOS, C, SXT, CT 0.75 32 16 2 7 8 2
23 C15 Typhimurium Chicken liver AM, AMC, CZ, CXM, CRO, FEB, FOX, CN, AK, NA, CIP, TE, FOS, C, SXT, ATM, CT 0.71 4 0.5 0.5 1 4 0.5
24 C16 Magherafelt Chicken cecum AM, AMC, SAM, CZ, CXM, CRO, FEB, FOX, IPM, ETP, MEM, DOR, TOB, NA, CIP, TE, TIG, FOS, C, SXT, CT 0.88 32 16 2 7 4 4
25 Q3 Jedburgh Quail liver AM, AMC, CZ, CXM, CRO, FEB, FOX, CN, TOB, NA, CIP, TE, TIG, FOS, SXT, ATM, CT 0.71 64 16 2 7 32 2
26 P1 Wingrove Pigeon liver AM, AMC, SAM, CZ, CXM, CRO, FEB, FOX, TOB, NA, CIP, TE, TIG, FOS, C, SXT, ATM 0.71 2 4 0.5 1 0.5 4
27 D3 Untypable Duck muscle AMC, SAM, CZ, CXM, FEB, FOX, CN, TOB, NA, CIP, TE, TIG, FOS, C, SXT, CT 0.67 2 4 1 3 2 2
28 H5 Typhimurium Human stool AM, AMC, SAM, CZ, CRO, FOX, IPM, ETP, MEM, DOR, CN, TOB, NA, CIP, TE, FOS, C, SXT, CT 0.79 8 1 0.5 1 4 1
29 C17 Typhimurium Chicken muscle AMC, SAM, CZ, CRO, FOX, CN, TOB, NA, CIP, TE, TIG, FOS, C, SXT, CT 0.63 32 8 1.5 5 16 4

XDR, extensive drug resistant; MAR, multiple antibiotic resistance; MIC, minimum inhibitory concentration; MCEtBr, minimum ethidium bromide concentration; AM, ampicillin; AMC, amoxycillin-clavulanic acid; SAM, ampicillin-sulbactam; CZ, cefazolin; CXM, cefuroxime; CRO, ceftriaxone; FEB, cefepime; FOX, cefoxitin; IPM, imipenem; ETP, ertapenem; MEM, meropenem; DOR, doripenem; CN, gentamicin; TOB, tobramycin; AK, amikacin; NA, nalidixic acid; CIP, ciprofloxacin; TE, tetracycline; TIG, tigecycline; FOS, fosfomycin; C, chloramphenicol; SXT, sulfamethoxazole-trimethoprim; ATM, aztreonam; CT, colistin; CCCP, carbonyl cyanide 3-chlorophenylhydrazone; H, human; C, chicken; D, duck; Q, quail; P, pigeon; CLSI, Clinical and Laboratory Standards Institute.

aSusceptibility of Salmonella isolates to colistin (CT) was determined using the broth microdilution method. Colistin MIC range was 4–32 μg/ml for resistant Salmonella isolates, while it was 0.5–2 μg/ml for those that were colistin sensitive (Nos. 7, 8, and 26).

bMICs for CIP and TIG were interpreted according to the relevant CLSI document.

cThe efflux pump index provided the range of efflux activity, which was reported for each strain in comparison with a pan-susceptible Salmonella Tamale control isolate (assigned a value of 0.25 μg/ml).