Open AccessCTX-M-type ESBL-mediated resistance to third-generation cephalosporins and conjugative transfer of resistance in Gram-negative bacteria isolated from hospitals in Tamil Nadu, India
Author(s) -
Ramesh Nachimuthu,
V. Rajesh Kannan,
Bülent Bozdoğan,
Vaithilingam Krishnakumar,
Karutha Pandian S,
Prasanth Manohar
Publication year - 2021
Publication title -
access microbiology
Language(s) - English
Resource type - Journals
ISSN - 2516-8290
DOI - 10.1099/acmi.0.000142
Subject(s) - cefotaxime , microbiology and biotechnology , providencia , ceftazidime , klebsiella pneumoniae , biology , cephalosporin , morganella morganii , shigella , enterobacter , citrobacter freundii , pseudomonas aeruginosa , salmonella , escherichia coli , bacteria , antibiotics , gene , genetics
Clinical pathogens, especially Gram-negative bacteria developing resistance to third-generation cephalosporins, are making clinical outcomes more complicated and serious. This study was undertaken to evaluate the distribution of CTX-M-type extended-spectrum β-lactamases (ESBLs) in Tamil Nadu, India. For this study, clinical samples were collected from five different hospitals located in Tamil Nadu and the ESBL-producing Gram-negative isolates were characterized. MIC was performed using cefotaxime and ceftazidime. The bla ESBL -producing genes were screened using multiplex PCR for the genes, CTX-M group-1, -2, -8, -9, -26. The conjugation studies were performed usingEscherichia coliAB1157 as a recipient for the isolates harbouring plasmid-borne resistance following broth-mating experiment. In total, 1500 samples were collected and 599 Gram-negative bacteria were isolated that includedE. coli( n =233),Klebsiella pneumoniae( n =182),Pseudomonas aeruginosa( n =79),Citrobacterspp. ( n =30),Proteus mirabilis( n =28),Salmonellaspp. ( n =21),Acinetobacter baumannii( n =12), Serratia spp . ( n =6),Shigellaspp. ( n =4),Morganella morganii( n =3) andProvidenciaspp. ( n =1). MIC results showed that 358 isolates were resistant to cefotaxime and ceftazidime. Further, ESBL gene-amplification results showed that 19 isolates had CTX-M group-1 gene includingE. coli( n =16) , K. pneumoniae ( n =2) andP. aeruginosa( n =1) whereas oneM. morganiiisolate had CTX-M group-9, which was plasmid-borne. Through conjugation studies, 12/20 isolates were found to be involved in the transformation of its plasmid-borne resistance gene. Our study highlighted the importance of horizontal gene transfer in the dissemination of plasmid-borne bla CTX-M-type resistance genes among the clinical isolates.