Resistance and Co-Resistance of Metallo-Beta-Lactamase Genes in Diarrheal and Urinary-Tract Pathogens in Bangladesh

Carbapenems are the antibiotics of choice for treating multidrug-resistant bacterial infections. Metallo-β-lactamases (MBLs) are carbapenemases capable of hydrolyzing nearly all therapeutically available beta-lactam antibiotics. Consequently, this research assessed the distribution of two MBL genes and three β-lactamases and their associated phenotypic resistance in diarrheal and urinary-tract infections (UTIs) to guide future policies. Samples were collected through a cross-sectional study, and β-lactamase genes were detected via PCR. A total of 228 diarrheal bacteria were isolated from 240 samples. The most predominant pathogens were <i>Escherichia coli</i> (32%) and <i>Klebsiella</i> spp. (7%). Phenotypic resistance to amoxicillin-clavulanic acid, aztreonam, cefuroxime, cefixime, cefepime, imipenem, meropenem, gentamicin, netilmicin, and amikacin was 50.4%, 65.6%, 66.8%, 80.5%, 54.4%, 41.6%, 25.7%, 41.2%, 37.2%, and 42.9%, respectively. A total of 142 UTI pathogens were identified from 150 urine samples. <i>Klebsiella</i> spp. (39%) and <i>Escherichia coli</i> (24%) were the major pathogens isolated. Phenotypic resistance to amoxicillin-clavulanic acid, aztreonam, cefuroxime, cefixime, cefepime, imipenem, meropenem, gentamicin, netilmicin, and amikacin was 93.7%, 75.0%, 91.5%, 93.7%, 88.0%, 72.5%, 13.6%, 44.4%, 71.1%, and 43%, respectively. Twenty-four diarrheal isolates carried <i>bla</i>NDM-1 or <i>bla</i>VIM genes. The overall MBL gene prevalence was 10.5%. Thirty-six UTI pathogens carried either <i>bla</i>NDM-1 or <i>bla</i>VIM genes (25.4%). Seven isolates carried both <i>bla</i>NDM-1 and <i>bla</i>VIM genes. MBL genes were strongly associated with phenotypic carbapenem and other β-lactam antibiotic resistance. <i>bla</i>OXA imparted significantly higher phenotypic resistance to β-lactam antibiotics. Active surveillance and stewardship programs are urgently needed to reduce carbapenem resistance in Bangladesh.