Concomitant quinolone resistance in extended-spectrum β-lactamase (ESBL)-producing
Between December 2007 and April 2008, we collected 60 and 69 clonally unrelated non-repetitive clinical isolates of ESBL-producing
We observed a high prevalence of the
The
Oligonucleotides of the primers used for amplification
Enzymes | Primer pairs | Sequence (5′-3′) | Amplicon size (bp) | Reference | |
---|---|---|---|---|---|
b-lactamase | TEM F | ATG AGT ATT CAA CAT TTC CGT | 861 | [9], In this study | |
TEM R | TTA CCA ATG CTT AAT CAG TGA | ||||
SHV F | CCG GGT TAT TCT TAT TTG TCG CT | 831 | |||
SHV R | TAG CGT TGC CAG TGC TCG | ||||
PER-F | GTT AAT TTG GGC TTA GGG CAG | 855 | |||
PER-R | CAG CGC AAT CCC CAC TGT | ||||
GES/IBC F | GTT AGA CGG GCG TAC AAA GAT AAT | 903 | |||
GES/IBC R | TGT CCG TGC TCA GGA TGA GT | ||||
CTX-MF | GAT TGA CCG TAT TGG GAG TTT | 947 | |||
CTX-MR | CGG CTG GGT AAA ATA GGT CA | ||||
CTX-M3F | AGT TCA CGC TGA TGG CGA CG | 602 | |||
CTX-M3R | AAC CCA GGA AGC AGG CAG CG | ||||
CTX-M8F | ACG CTC AAC ACC GCG ATC | 954 | |||
CTX-M8R | CGT GGG TTC TCG GGG ATA A | ||||
VEB F | CGA CTT CCA TTT CCC GAT GC | 650 | |||
VEB R | GGA CTC TGC AAC AAA TAC GC | ||||
Qnr | qnrA F | GGG TAT GGA TAT TAT TGA TAA AG | 660 | [10] | |
qnrA R | CTA ATC CGG CAG CAC TAT TA | ||||
qnrB F | GGM ATH GAA ATT CGC CAC TG | 264 | |||
qnrB R | TTT GCY GYY CGC CAG TCG AA | ||||
qnrS F | AGT GAT CTC ACC TTC ACC GC | 550 | |||
qnrS R | CAG GCT GCA ATT TTG ATA CC | ||||
16S rRNA methylase | armA F | AGG TTG TTT CCA TTT CTG AG | 776 | [11,12] | |
armA R | TCT CTT CCA TTC CCT TCT CC | ||||
rmtA F | CTAGCGTCCATCCTTTCCTC | 635 | |||
rmtA R | TTT GCT TCC ATG CCC TTG CC | ||||
rmtB F | CCC AAA CAG ACC GTA GAG GC | 769 | |||
rmtB R | CTC AAA CTC GGC GGG CAA GC | ||||
rmtC F | CGA AGA AGT AAC AGC CAA AG | 700 | |||
rmtC R | ATC CCA ACA TCT CTC CCA CT | ||||
aac(6′)-Ib | aac(6′)F | TGA CCA ACA GCA ACG ATT CC | 500 | [13] | |
aac(6′)R | TTA GGC ATC ACT GCG TGT TC |
Abbreviations: F, forward; R, reverse.
Species-specific distributions of antibiotic resistance genes
Genes | Total N=129 | |||
---|---|---|---|---|
41 (68.3) | 33 (47.8) | 74 (57.0) | 0.03 | |
5 (8.3) | 65 (94.2) | 70 (54.0) | ≤0.0001 | |
34 (56.7) | 11 (15.9) | 45 (35.0) | ≤0.0001 | |
2 (3.3) | 11 (15.9) | 13 (10.0) | 0.02 | |
18 (30.0) | 12 (17.4) | 30 (23.0) | 0.1384 | |
6 (10.0) | 4 (5.8) | 10 (8.0) | 0.5127 | |
34 (56.7) | 8 (11.6) | 42 (33.0) | ≤0.0001 | |
0 (0) | 5 (7.2) | 5 (4.0) | 0.0607 | |
0 (0) | 1 (1.4) | 1 (1.0) | 1 | |
4 (6.7) | 7 (10.1) | 11 (9.0) | 0.5424 | |
37 (61.7) | 7 (10.1) | 44 (34.0) | ≤0.0001 | |
14 (23.3) | 46 (66.7) | 60 (47.0) | ≤0.0001 | |
39 (65.0) | 33 (47.8) | 72 (55.8) | 0.0748 | |
25/39 (64.1) | 19/33 (57.6) | 44 (61.1) | ||
wild-type |
14/39 (35.9) | 14/33 (42.4) | 28 (38.9) | |
0 (0) | 1 (1.4) | 1 (1.0) | 1 | |
1 (1.7) | 49 (71.0) | 50 (39.0) | ≤0.0001 | |
24 (40.0) | 5 (7.2) | 29 (22.0) | ≤0.0001 |
Statistical analysis for categorical variables and incidence across series were performed using Pearson's chi test and Fisher's exact tests;
The ratio of
Prevalence of the
Strain (N [%]) | ||||
---|---|---|---|---|
0 (0) | 0 (0) | 19 (100) | 12 (63.2) | |
1 (0.04) | 21 (87.5) | 3 (12.5) | 17 (70.8) | |
Total 43 | 1 (0.02) | 21 (48.8) | 22 (51.2) | 29 (67.4) |
Cassette arrays of the type-1 integrons detected in the 43 strains coharboring
Type of cassette array | Sequence of cassette | Size (kb) | Isolates | |
---|---|---|---|---|
1 | 1.8 | 5 | 0 | |
2 | 1.1 | 0 | 12 | |
3 | 1.6 | 0 | 1 | |
4 | 2.5 | 1 |
0 | |
5 | 3.0 | 0 | 1 | |
6 | 1.2 | 0 | 1 | |
Total | 5 | 15 |
Simultaneously harbored type 1 cassette array in the isolate.
Minimum inhibitory concentration values and resistance gene profiles of the 11 strains showing high-level resistances to quinolone or aminoglycoside
Species | No. strain | Array type | NOR | CIP | TOB | GEN | AMK | |||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
100 | . | Ib | N | N | P | P | N | P | >128 | >32 | 16 | >128 | 64 | |
23 | 1,4 | Ib | N | N | P | N | N | N | >128 | >32 | 16 | 16 | 8 | |
21 | 1 | Ib | N | N | P | P | N | P | >128 | >32 | 4 | 16 | ≤2 | |
126 | . | cr | N | P | N | N | N | N | >128 | >32 | >128 | >128 | >512 | |
37 | . | cr | N | P | N | P | N | N | >128 | >32 | >128 | 32 | >512 | |
42 | . | cr | N | P | N | N | N | N | >128 | 8 | >128 | >128 | 128 | |
28 | 2 | cr | N | P | N | P | N | N | >128 | 2 | >128 | >128 | >512 | |
31 | . | cr | N | P | N | P | N | N | >128 | 4 | 64 | >128 | >512 | |
33 | 6 | cr | N | P | N | P | N | N | >128 | 4 | >128 | >128 | 64 | |
45 | 2 | cr | N | P | N | P | N | N | >128 | 2 | >128 | 64 | 64 | |
44 | 2 | cr | N | P | N | P | N | N | >128 | 2 | >128 | 16 | 64 |
Abbreviations: CIP, ciprofloxacin; TOB, tobramycin; GEN, gentamicin; AMK, amikacin; NOR, norfloxacin; N, negative; P, positive.
Candidate resistance genes showing statistical association with the minimum inhibitory concentration values of quinolones and aminoglycosides in the 43 strains cohaboring
N | NOR | CIP | TOB | GEN | AMK | ||
---|---|---|---|---|---|---|---|
Positive | 21 | 53.4±55.3 | 40.5±51.9 | 136±190 | |||
Negative | 22 | 11.5±5.6 | 15.5±26.6 | 14.2±21.3 | |||
≤0.001 | 0.0044 | ≤0.001 | |||||
Positive | 22 | 14.8±26.8 | 11.6±18 | ||||
Negative | 21 | 41.2±51.4 | 138.6±188.5 | ||||
0.0054 | ≤0.001 | ||||||
Positive | 4 | 6±2.3 | 2.1±2.0 | 9.2±7.8 | 9.2±7.8 | 19.5±29.7 | |
Negative | 39 | 41.8±55.7 | 7±9.7 | 34.9±45.8 | 30±44.4 | 81.0±153.3 | |
0.0002 | 0.025 | 0.0139 | 0.0153 | 0.0199 | |||
Positive | 14 | 10±6.2 | 14.7±22.4 | ||||
Negative | 29 | 42.5±50.2 | 102.2±170.2 | ||||
≤0.001 | ≤0.001 | ||||||
Positive | 29 | 5.2±7.7 | 42.2±51.6 | 97.4±175.6 | |||
Negative | 14 | 9±12.5 | 12.9±5.2 | 30.5±30.2 | |||
0.0324 | ≤0.001 | ≤0.001 |
The Wilcoxon rank-sum test was used to compare the group mean (negative vs positive) values;
Abbreviations: CIP, ciprofloxacin; TOB, tobramycin; GEN, gentamicin; AMK, amikacin; NOR, norfloxacin.
Amplified association between the candidate genes and the minimum inhibitory concentration values of quinolones and amino-glycosides in the 29 strains co-harboring
N | NOR | CIP | TOB | GEN | AMK | ||
---|---|---|---|---|---|---|---|
Positive | 16 | 67±63.0 | 6.0±10.0 | 65.1±58.9 | 50.1±56.3 | 161.5±212.3 | |
Negative | 13 | 7±1.8 | 3.5±1.7 | 11.7±5.5 | 10.2±7.1 | 12.0±17.3 | |
≤0.001 | ≤0.001 | ≤0.001 | ≤0.001 | ≤0.001 | |||
Positive | 13 | 6.6±1.9 | 6.6±10.0 | 65.1±58.9 | 161.5±212.2 | ||
Negative | 16 | 67.2±62.5 | 3.5±1.1 | 11.7±5.5 | 12±17.3 | ||
≤0.001 | ≤0.001 | ≤0.001 | ≤0.001 | ||||
Positive | 3 | 7±7.9 | |||||
Negative | 26 | 36.2±48.6 | |||||
0.0526 | |||||||
Positive | 8 | 9.8±6.2 | 7.1±6.4 | ||||
Negative | 21 | 53.0±55.6 | 127.5±194.5 | ||||
≤0.001 | ≤0.001 |
The Wilcoxon rank-sum test was used to compare the group mean (negative vs positive) values;
Abbreviations: See Table 6.