Table 1. Resistant (R) and Wild Type (WT) E. coli isolated from Vembanad Lake, Kerala, India
S. No.
|
Code
|
Antibiotic name
|
Antibiotic class/Subclass
|
%R*
|
% WT**
|
P***
|
1
|
AMP_10
|
Ampicillin
|
Penicillins / Aminopenicillin
|
28.4
|
75.86
|
0.28
|
|
2
|
AMC_20
|
Amoxicillin/Clavulanic acid
|
Beta-lactam+Inhibitors
|
4.3
|
97.41
|
0.04
|
|
3
|
CAZ_30
|
Ceftazidime
|
Cephems / Cephalosporin III
|
14.7
|
99.13
|
0.13
|
|
4
|
CRO_30
|
Ceftriaxone
|
Cephems/ Cephalosporin III
|
18.1
|
81.89
|
0.18
|
|
5
|
CTX_5
|
Cefotaxime
|
Cephems / Cephalosporin III
|
71.6
|
87.93
|
0.71
|
|
6
|
FOX_30
|
Cefoxitin
|
Cephems / Cephamycin
|
3.4
|
98.27
|
0.03
|
|
7
|
CPD_10
|
Cefpodoxime
|
Cephems-Oral / Cephalosporin
|
3.4
|
54.31#
|
0.03
|
|
8
|
ATM_30
|
Aztreonam
|
Monobactams
|
12.1
|
93.96
|
0.12
|
|
9
|
IPM_10
|
Imipenem
|
Penems/ Carbapenems
|
12.1
|
94.82
|
0.12
|
|
10
|
GEN_10
|
Gentamicin
|
Aminoglycosides
|
0
|
100
|
0.00
|
|
11
|
NAL_30
|
Nalidixic acid
|
Quinolones
|
15.5
|
84.48
|
0.15
|
|
12
|
CIP_5
|
Ciprofloxacin
|
Quinolones Fluoroquinolone
|
3.4
|
69.65#
|
0.03
|
|
13
|
SXT_1.2
|
Trimethoprim/Sulfamethoxazole
|
Folate pathway inhibitors
|
8.6
|
91.4
|
0.08
|
|
14
|
CHL_30
|
Chloramphenicol
|
Phenicols
|
1.7
|
98.3
|
0.01
|
|
15
|
TCY_30
|
Tetracycline
|
Tetracyclines
|
20.7
|
87.93
|
0.19
|
|
Data analysed in WHONET version 5.6 as per CLSI 2019 breakpoints; Numeric values in Code denotes the concentration of antibiotic used in disk; ND-Not determined; *R-Resistant isolates based on CLSI breakpoints; **WT – Wild Type isolates based on Ecoff; values (Ampicillin ≥11mm, Amoxicillin/Clavulanic acid ≥12mm, Ceftazidime ≥10mm, Ceftriaxone ≥20mm, Cefotaxime ≥10mm, Cefoxitin ≥11mm, Cefpodoxime ≥24mm, Aztreonam ≥12mm, Imipenem ≥18mm, Nalidixic acid ≥12mm, Ciprofloxacin ≥23mm, Trimethoprim/Sulfamethoxazole ≥22mm, Chloramphenicol ≥12mm, Tetracycline ≥9mm); ***Probability of isolating AMR E. coli in the lake based on logistic regression analysis; #WT strain numbers reduced after deducing Ecoff value.
Table 2. Variations in AMR patterns of Extended Spectrum β-lactamase Escherichia coli (ESBL) and other E. coli isolated from Vembanad Lake, Kerala, India
S. No
|
AMR pattern
|
Resistance to antibiotic class / classes
|
S. No
|
AMR pattern
|
Resistance to antibiotic classes
|
1
|
CTX (37)*
|
42.5%**
(1 class)
|
21
|
CTX-NAL-SXT-TCY (1)
|
3.1%
(4 classes)
|
2
|
SXT (1)
|
22
|
AMP-CTX-CAZ-CRO (1)
|
3
|
CRO (2)
|
23
|
AMP-FOX-CTX-CRO (1)
|
4
|
AMP-NAL (2)
|
20.2%
(2 classes)
|
24
|
AMP-CTX-CAZ-CRO-ATM (7)
|
11.7%
(5 classes)
|
5
|
AMP-CTX (2)
|
25
|
CTX-IPM-NAL-SXT-TCY (1)
|
6
|
SXT-TCY (1)
|
26
|
AMP-CTX-NAL-CIP-TCY (1)
|
7
|
CTX-TCY (7)
|
27
|
AMP-IPM-NAL-SXT-TCY (1)
|
8
|
FOX-CTX (2)
|
28
|
CTX-CAZ-CRO-ATM-IPM (1)
|
9
|
CRO-TCY (1)
|
29
|
AMP-CTX-CAZ-CRO-ATM-IPM (2)
|
7.4%
(6 classes)
|
10
|
CRO-NAL (1)
|
30
|
AMP-CTX-IPM-NAL-SXT-TCY (1)
|
11
|
CTX-NAL (1)
|
31
|
AMP-CTX-CAZ-CRO-ATM-TCY (1)
|
12
|
AMC-CTX (1)
|
32
|
AMP-CTX-CPD-IPM-NAL-SXT (1)
|
13
|
CTX-CAZ (1)
|
33
|
AMP-CTX-ATM-IPM-CIP-TCY (1)
|
14
|
CTX-IPM-TCY (1)
|
9.5%
(3 classes)
|
34
|
AMP-CTX-CAZ-CRO-ATM-TCY (1)
|
15
|
FOX-CTX-IPM (1)
|
35
|
AMP-CTX-CAZ-CRO-ATM-IPM-NAL (1)
|
4.2%
(7 classes)
|
16
|
AMP-CTX-TCY (1)
|
36
|
AMP-AMC-CTX-CPD-IPM-NAL-SXT (1)
|
17
|
AMP-SXT-TCY (1)
|
37
|
AMP-AMC-CTX-CPD-IPM-NAL-CIP (1)
|
18
|
AMP-CTX-CHL (1)
|
38
|
AMP-CTX-CAZ-CRO-ATM-NAL-TCY (1)
|
19
|
AMC-CRO-TCY (1)
|
39
|
AMP-AMC-CTX-CPD-IPM-NAL-CIP-SXT-TCY (1)
|
1.06%
(9 classes)
|
20
|
AMP-CTX-NAL (3)
|
|
Susceptible to all fifteen antibiotics
|
19%***
(0 classes)
|
Note: CTX –Cefotaxime; AMP-Ampicillin; TCY-Tetracycline; CRO-Ceftriaxone; NAL- Nalidixic acid; CAZ-Ceftazidime; IPM- Imipenem; ATM- Aztreonam; SXT-Trimethoprim/Sulfamethoxazole; AMC-Amoxicillin/Clavulanic acid; CPD-Cefpodoxime; FOX-Cefoxitin; CIP-Ciprofloxacin; CHL-Chloramphenicol.*Number of E.coli isolates resistant to specific antibiotic class or classes; ** Cumulative resistance expressed as percentage of all AMR E.coli isolates (n=94); *** Susceptibility expressed as percentage of total E. coli isolates (n=116)
Table 3. Distribution of ESBL genes in E. coli isolated from Vembanad Lake
Genes
|
Phenotypically ESBL positive isolates (CDD assay) n= 37
|
Phenotypically ESBL negative isolates (CDD assay) n=46
|
ESBL gene incidence
(n=83)
|
|
Alapuzha (n=12)
|
Ernakulam (n=4)
|
Kottayam*** (n=21)
|
Alapuzha * (n=14)
|
Ernakulam (n=12)
|
Kottayam** (n=20)
|
|
blaTEM
|
12
blaTEM-116
|
4
blaTEM-116
|
17
blaTEM-1 (1)
blaTEM-116
|
12
blaTEM-1 (1)
blaTEM-116
|
11
blaTEM-1 (6)
blaTEM-116
|
15
blaTEM-1 (7)
blaTEM-116
|
85.5%
(18% blaTEM-1)
(67.4% blaTEM-116)
|
blaSHV
|
0
|
1
blaSHV-27
|
0
|
1
blaSHV-27
|
0
|
0
|
2.4%
|
blaCTX-M group 1
|
1
blaCTX-M-55
|
1
blaCTX-M-55
|
4
blaCTX-M-55
|
1
blaCTX-M-55
|
0
blaCTX-M-55
|
2
blaCTX-M-55
|
10.8%
|
blaCTX-M group 2
|
0
|
0
|
1
blaCTX-M-205
|
0
|
0
|
1
blaCTX-M-205
|
2.4%
|
blaCTX-M group 9
|
1
blaCTX-M-27
|
1
blaCTX-M-27
|
6
blaCTX-M-27
|
2
blaCTX-M-27
|
4
blaCTX-M-27
|
4
blaCTX-M-27
|
21.6%
|
blaCTX-M group 8/25
|
0
|
1
blaCTX-M-152
|
0
|
0
|
0
|
0
|
1.2%
|
blaOXA-1-like
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
|
|
|
|
|
|
|
|
* One isolate from Alapuzha CDD-ve did not harbor any of the ESBL genes tested
** Three isolates from Kottayam CDD-ve did not harbor any of the ESBL genes tested
*** Two isolates from Kottayam Region CDD+ve did not harbor any of the ESBL genes tested
Out of four CPD resistant isolates tested, two were CDD+ve and two were CDD-ve
All fourteen CAZ and fourteen ATM resistant isolates tested were CDD+ve