Molecular Epidemiology of Extensively Drug-Resistant Encoded Colistin-Resistant Bacterial Strains Co-Expressing Multifarious β-Lactamases.

Plasmid-mediated colistin resistance (Col-R) conferred by genes endangers the last therapeutic option for multifarious β-lactamase-producing bacteria. The current study aimed to explore the gene molecular epidemiology in extensively drug-resistant (XDR) bacteria. Col-R gram-negative bacterial strains were screened using a minimum inhibitory concentration (MIC) breakpoint ≥4 µg/mL. Resistant isolates were examined for variants, extended-spectrum β-lactamase, AmpC, and carbapenemase genes using polymerase chain reaction (PCR). The MIC breakpoints for -positive strains were determined using broth microdilution and E-test strips. Overall, 19/718 (2.6%) gram-negative rods (GNRs) harboring were identified, particularly in pus ( = 0.01) and tracheal secretions ( = 0.03). Molecular epidemiology data confirmed 18/19 (95%) -1 and 1/19 (5%) -2 genes. Integron detection revealed 15/17 (88%) and 2/17 (12%) . Common co-expressing drug-resistant β-lactamase genes included 8/16 (50%) , 3/16 (19%) , 3/3 (100%) , 2/8 (25%) , and 2/8 (25%) . The MIC and MIC values (µg/mL) were as follows: , 12 and 24; , 12 and 32; , 8 and 12; and , 32 and 64, respectively. Treatment of XDR strains has become challenging owing to the co-expression of -1, -2, multifarious β-lactamase genes, and integrons.