Prevalence and distribution pattern of AmpC β-lactamases in ESBL producing clinical isolates of Klebsiella spp. in parts of Assam, India.

The production of extended-spectrum β-lactamases (ESBLs) and AmpC β-lactamases is the most common explanation of multidrug resistance in clinical isolates of Klebsiella spp. In the present study, a total of 160 isolates of Klebsiella spp. were procured from the DBT-NER project with ethical clearance no. DU/Dib/ECBHR(Human)/2021-22/02). These were collected from various health settings of Assam and identified as drug-resistant. The isolates were screened for antibiotic susceptibility and phenotypic tests were performed on multidrug resistant isolates to confirm ESBL and AmpC β-lactamases production. The distribution pattern of ESBL and AmpC β-lactamase genotype was investigated by polymerase chain reaction (PCR). The results showed that among 107 multidrug-resistant (MDR) isolates of Klebsiella spp., 67.28% of isolates were ESBL producers and 56.07% were potential AmpC producers. The PCR results revealed that bla CTX-M was the most prevalent ESBL genotype. Among the ESBL producers, 11.11% of isolates showed co-occurrence with plasmid-mediated AmpC β lactamases genotype which indicated the high prevalence of ESBL and AmpC co-producers in K. pneumoniae and K. oxytoca, suggesting the possibility of serious public health concerns. Therefore, it is crucial to regularly monitor the spread of multidrug resistance among clinical isolates.