Plasmid-Mediated AmpC (pAmpC) Genotypes Among Uropathogenic Escherichia coli: A Hospital-Based Study From Western Uttar Pradesh

Abstract

Resistance due to AmpC and extended-spectrum beta (β)-lactamases (ESBLs) in Escherichia coli is an emerging problem worldwide. AmpC enzymes are a subclass of β-lactamases that have a capacity to hydrolyze and deactivate a large range of β-lactam antibiotics, particularly cephalosporins, penicillins, and monobactams, although frequently being susceptible to carbapenems and fourth-generation cephalosporins. The prevalence of plasmid-mediated AmpC (pAmpC) genotypes in uropathogenic E. coli isolates were looked at a tertiary care teaching hospital of Western Uttar Pradesh. Materials and methodsA total of 312 non-repeat clinical E. coli isolates among patients presented with urinary tract infections (UTIs) were investigated by standard microbiological methods. Isolates were screened for the presence of ampC using a cefoxitin (30 µg) disc and confirmed using an inhibitor-based assay. Using multiplex polymerase chain reaction (PCR), six AmpC genotypes, namely, CIT, DHA, EBC, ACC, FOX, and MOX, were genotypically identified. ResultsA total of 152 (48.72%) uropathogenic E. coli isolates tested positive on the cefoxitin screening. Out of which, AmpC production was confirmed in 118/152 (77.63%) using a phenotypic method. In particular, the pAmpC gene was found in 56/152 (36.84%) isolates. CIT was the most common gene detected in this geographical area (57.14 %). Multiple genes, i.e., CIT and FOX, were also detected in 14.29% of the isolates. ConclusionIdentifying AmpC producers is important in routine microbiology laboratory as they are a nosocomial threat requiring strict adherence to infection control protocols. A confirmatory phenotypic test followed by genotypic tests will help in the correct and accurate identification of this resistance.

Phenotypic identification of different β-Lactamases in intrinsic and acquired colistin resistant uropathogenic gram negative bacteria

“…5 Other Enterobacteriaceae family members produce the class C βlactamases (AmpC enzymes) that are active against cephamycin in addition to third generation cephalosporins, and are also resistant to β-lactamase inhibitors. 7 The expression of AmpC enzymes is also associated with carbapenem resistance in K. pneumoniae strains lacking a 42 kDa outer membrane protein. 8 Treating Multi drug resistant bacteria, colistin was used as a last line of antibiotic for gram negative bacteria.…”