Carriage of ndm & imp carbapenem resistance genes among e. Coli & k. Pneumoniae in human stool isolates from Mbarara hospital

Abstract

Escherichia coli and Klebsiella pneumoniae have become intrinsically resistant to many types of β-lactamase due to the emergence of organisms carrying NDM and IMP genes(Liang et al., 2020). Carbapenems, among the beta-lactams, are the most effective agents for the treatment of severe infection caused by ESBL-positive E. coli and K.pneumoniae, and their unique molecular structure is due to the presence of a carbapenem together with the beta-lactam ring(Sen and Joshi, 2016). Resistance to carbapenems occurs due to the production of carbapenemases, a class of enzymes capable of hydrolyzing carbapenems and other β-lactams; the other mechanisms can be by the poor binding of carbapenems to penicillin-binding proteins present in the bacteria, lack of porins present in the bacterial cell membrane, and overexpression of multidrug efflux pumps by the bacteria(Dong et al., 2019). They are classes of enzymes capable of hydrolyzing carbapenems and other β-lactams, including classes A, B, and D. KPCs are the most frequently encountered enzymes in class A carbapenemases. Class B metallo-β-lactamases (MBLs) are mostly of the VIM, IMP, SPM, GM, SIM, and NDM. Class D β-lactamases, also named OXAs, OXA-48, represent the main enzyme isolated around the world(Roach et al., 2020). Objective The objective of the study was to determine the frequency of NDM and IMP carbapenem resistance genes among E. coli and K. pneumoniae isolates from Mbarara Hospital, Uganda. Methods This was a laboratory-based study conducted between December and February 2022, using isolates of E.coli and K. pneumonia from stool samples from Mbarara hospital, Uganda. Results Out of the 32 samples of emulsified stool only 31 grew on LB media and one did not show any growth and was discarded. Of the total of 31 isolates of, three E. coli isolates (9.4%) were positive for NDM gene well positions; 8 (E. coli38), 10(E. coli41) & 14 (E. coli49) meanwhile IMP was detected among two isolates (6.3%) at positions 11(E. coli42) and 18 (E. coli59).