Background
Methods
Study design and setting
Sample collection
Microbiological identification
Minimum inhibitory concentrations (MICs) against colistin
Disc diffusion antibiotic testing
Molecular detection of mcr genes and data analysis
Results
Association of Col-R in human and animal isolates
Organisms | Animal isolates (n = 1285) | Human isolates (n = 5893) | ||||
---|---|---|---|---|---|---|
Total
| Col-S
| Col-R
| Total
| Col-S
| Col-R
| |
E. coli
| 658 | 567 (86.2%) | 91 (13.8%) | 2219 | 2216 (99.9%) | 3 (0.1%) |
Klebsiella species | 231 | 219 (94.8%) | 12 (5.2%) | 1592 | 1591 (99.9%) | 1 (0.1%) |
Pseudomonas species | 81 | 78 (96.3%) | 3 (3.7%) | 995 | 995 (100%) | 0 (0%) |
Citrobacter species | 89 | 89 (100%) | 0 (0%) | 351 | 351 (100%) | 0 (0%) |
Acinetobacter species | 0 | 0 (0%) | 0 (0%) | 318 | 315 (99.1%) | 3 (0.9%) |
Enterobacter species | 85 | 85 (100%) | 0 (0%) | 260 | 260 (100%) | 0 (0%) |
Proteus species | 20 | 0 (0%) | 20 (100%) | 10 | 0 (0%) | 10 (100%) |
Salmonella species | 109 | 109 (100%) | 0 (0%) | 85 | 85 (100%) | 0 (0%) |
Sphingomonas paucimobilis
| 0 | 0 (0%) | 0 (0%) | 25 | 25 (100%) | 0 (0%) |
Chryseomonas luteola
| 4 | 4 (100%) | 0 (0%) | 19 | 19 (100%) | 0 (0%) |
Pantoea species | 8 | 8 (100%) | 0 (0%) | 19 | 19 (100%) | 0 (0%) |
Organism | Col-R animal source n (%) | Col-R human source n (%) | P-value |
---|---|---|---|
126 (88.1)
|
17 (11.9)
| ||
E. coli
| 91 (72.2) | 3 (17.6) | < 0.01 |
K. pneumoniae
| 12 (9.5) | 1 (5.9) | 0.62 |
P. aeruginosa
| 3 (2.4) | 0 (0) | 0.52 |
A. baumannii
| 0 (0) | 3 (17.6) | < 0.01 |
P. mirabilis
| 20 (15.9) | 10 (58.8) | < 0.01 |
Distribution of Col-R strains from different specimens
Drug-resistance spectrum against various antibiotics
Antibiotics | Animal isolates | Human isolates | P-value |
---|---|---|---|
n = 126 (%)
|
n = 17 (%)
| ||
Co-trimoxazole | 101 (80.2) | 8 (47.1) | 0.01 |
Chloramphenicol | 92 (73) | 9 (52.9) | 0.05 |
Moxifloxacin | 90 (71.4) | 7 (41.2) | 0.03 |
Levofloxacin | 41 (32.5) | 4 (23.5) | 0.59 |
Ciprofloxacin | 42 (33.3) | 4 (23.5) | 0.69 |
Co-amoxiclav | 37 (29.4) | 9 (52.9) | 0.05 |
Cefotaxime | 33 (26.2) | 10 (58.8) | 0.01 |
Cefixime | 32 (25.4) | 9 (52.9) | 0.02 |
Cefuroxime | 29 (23) | 10 (58.8) | 0.007 |
Ceftriaxone | 28 (22.2) | 11 (64.7) | 0.01 |
Ceftazidime | 25 (19.8) | 10 (58.8) | < 0.01 |
Amikacin | 20 (15.9) | 4 (23.5) | 0.73 |
Imipenem | 16 (12.7) | 5 (29.4) | < 0.01 |
Cefoperazone-sulbactam | 12 (9.5) | 4 (23.5) | 0.22 |
Piperacillin-tazobactam | 10 (7.9) | 2 (11.8) | 0.05 |
Meropenem | 10 (7.9) | 5 (29.4) | 0.02 |
Antibiotics |
E. coli
|
K. pneumoniae
|
P. aeruginosa
|
A. baumannii
|
P. mirabilis
| |||||
---|---|---|---|---|---|---|---|---|---|---|
Animal
|
Human
|
Animal
|
Human
|
Animal
|
Human
|
Animal
|
Human
|
Animal
|
Human
| |
(n = 91)
|
(n = 3)
|
(n =12)
|
(n = 1)
|
(n = 2)
|
(n = 0)
|
(n = 0)
|
(n = 3)
|
(n = 20)
|
(n = 10)
| |
Co-trimoxazole | 64 (70%) | 3 (100%) | 5 (42%) | 1 (100%) | 2 (100%) | – | – | 3 (100%) | 8 (40%) | 10 (100%) |
Chloramphenicol | 64 (70%) | 3 (100%) | 5 (42%) | 1 (100%) | 2 (100%) | – | – | 3 (100%) | 8 (40%) | 4 (40%) |
Moxifloxacin | 59 (65%) | 2(67%) | 5 (42%) | 1 (100%) | 2 (100%) | – | – | 3 (100%) | 3 (15%) | 4 (40%) |
Levofloxacin | 21 (23%) | 1 (33%) | 3 (25%) | 1 (100%) | 2 (100%) | – | – | 2 (75%) | 3 (15%) | 1 (10%) |
Ciprofloxacin | 38 (42%) | 0 (0%) | 2 (17%) | 1 (100%) | 2 (100%) | – | – | 3 (100%) | 5 (25%) | 1 (10%) |
Co-amoxiclav | 39 (43%) | 2 (67%) | 1 (8%) | 1 (100%) | 0 (0%) | – | – | 3 (100%) | 6 (30%) | 1 (10%) |
Cefotaxime | 35 (38%) | 1 (33%) | 1 (8%) | 1 (100%) | 0 (0%) | – | – | 2 (75%) | 3 (15%) | 1 (10%) |
Cefixime | 29 (32%) | 2 (67%) | 3 (25%) | 1 (100%) | 0 (0%) | – | – | 3 (100%) | 6 (30%) | 3 (30%) |
Cefuroxime | 27 (30%) | 2 (67%) | 0 (0%) | 1 (100%) | 0 (0%) | – | – | 3 (100%) | 7 (35%) | 3 (30%) |
Ceftriaxone | 27 (30%) | 2 (67%) | 1 (8%) | 1 (100%) | 0 (0%) | – | – | 3 (100%) | 7 (35%) | 3 (30%) |
Ceftazidime | 27 (30%) | 1 (33%) | 0 (0%) | 1 (100%) | 0 (0%) | – | – | 3 (100%) | 1 (5%) | 3 (30%) |
Amikacin | 16 (18%) | 1 (33%) | 3 (25%) | 1 (100%) | 0 (0%) | – | – | 2 (75%) | 2 (10%) | 0 (0%) |
Imipenem | 12 (13%) | 1 (33%) | 3 (25%) | 1 (100%) | 0 (0%) | – | – | 1 (33%) | 0 (0%) | 2 (20%) |
Cefoperazone-sulbactam | 7 (8%) | 1 (33%) | 2 (17%) | 1 (100%) | 1 (50%) | – | – | 2 (67%) | 2 (10%) | 0 (0%) |
Piperacillin-tazobactam | 9 (10%) | 0 (0%) | 0 (0%) | 1 (100%) | 0 (0%) | – | – | 0 (0%) | 2 (10%) | 1 (10%) |
Meropenem | 9 (10%) | 1 (33%) | 1 (8%) | 1 (100%) | 0 (0%) | – | – | 3 (100%) | 2 (10%) | 0 (0%) |
MICs of colistin against Col-R bacterial strains
Occurrence of mcr genes in isolated bacteria
Bacterial strains | mcr-1 (n = 108; 98.2%) | mcr-2 (n = 2; 1.8%) | ||
---|---|---|---|---|
Animal n (%)
|
Human n (%)
|
Animal n (%)
|
Human n (%)
| |
104 (96.3)
|
4 (3.7)
|
2 (100)
|
0 (0)
| |
E. coli
| 90 (83.3) | 3 (2.8) | 0 (0) | 0 (0) |
K. pneumoniae
| 12 (11.1) | 1 (0.9) | 0 (0) | 0 (0) |
P. aeruginosa
| 1 (0.9) | 0 (0) | 0 (0) | 0 (0) |
P. mirabilis
| 1 (0.9) | 0 (0) | 2 (100) | 0 (0) |
A. baumannii
| 0 (0) | 0 (0) | 0 (0) | 0 (0) |
Demographic and clinical data for the human isolates
Gender | Age (Years) | Ward | Organism isolated | Specimen | Colistin MIC µg/mL | mcr gene |
---|---|---|---|---|---|---|
Male | 1 | Medical ICU |
K. pneumoniae
| Blood | 6 | mcr-1 |
Female | 38 | Outpatient department |
E. coli
| Urine | 6 | mcr-1 |
Female | 3 | Nephrology Ward |
E. coli
| Urine | 12 | mcr-1 |
Male | 67 | Cardiac ICU |
E. coli
| Urine | 6 | mcr-1 |
Female | 53 | Medical ICU |
A. baumannii
| Tracheal secretions | 8 | Not detected |
Male | 3 | Neurosurgery ICU |
A. baumannii
| Tracheal secretions | 8 | Not detected |
Female | 61 | Medical ICU |
A. baumannii
| Tracheal secretions | 6 | Not detected |
Female | 13 | Outpatient department |
P. mirabilis
| Urine | ≥ 264 | Not detected |
Male | 68 | Medical Ward |
P. mirabilis
| Urine | ≥ 264 | Not detected |
Male | 51 | Medical Ward |
P. mirabilis
| Stool | ≥ 264 | Not detected |
Female | 8 | Nephrology Ward |
P. mirabilis
| Blood | ≥ 264 | Not detected |
Male | 3 | Medical ICU |
P. mirabilis
| Tracheal secretions | ≥ 264 | Not detected |
Male | 3 | Ortho Ward |
P. mirabilis
| Pus | ≥ 264 | Not detected |
Male | 10 | General Surgery Ward |
P. mirabilis
| Pus | ≥ 264 | Not detected |
Male | 73 | Cardiac ICU |
P. mirabilis
| Tracheal secretions | ≥ 264 | Not detected |
Female | 6 | Neurosurgery Ward |
P. mirabilis
| CSF | ≥ 264 | Not detected |
Female | 3 | Medical Ward |
P. mirabilis
| Urine | ≥ 264 | Not detected |