Detection of Metallo-Beta-Lactamase Producing Bacteria in Some Sachet Water Sold within Calabar Metropolis, Nigeria

Abstract

Bacterial antibiotics resistance is a recurring problem that have resulted in increased morbidity and mortality rates over the decades. The Metallo-beta-lactamase (MBL) producing bacteria show resistance to carbapenems and most beta lactams, hence, constituting a major threat to an effective bacterial chemotherapy especially among the neonates, immune compromised and the senescent. This study was carried out to detect MBL producing bacteria in different brands of sachet water sold within Calabar metropolis. From a total of 10 different brands of sachet water samples, 50 non-duplicate gram-negative bacterial isolates of Acinetobacter spp (n=1), Aeromonas spp (n=6), Citrobacter spp (6), Enterobacter spp (n=6), Escherichia spp (n=2), Klebsiella spp (n=2), Plesiomonas spp (n=2), Proteus spp (n=3), Pseudomonas spp (n=2), Salmonella spp (n=3), Serratia spp (n=2) were tested for susceptibility to imipenem using disk diffusion method. Among the isolates, 35(70%) showed full and intermediate resistance to imipenem; 10(29%) showed MBL production by the DDST and 19(54%) via the CDT method while 7(20%) were confirmed MBL producer using both phenotypic methods. Statistical comparison of both methods using the student t test showed no significance (p>0.05). All the isolates were only susceptible to streptomycin and showed resistance to orfloxacin, gentamycin, augmentin, ceftazidime and cefuroxime. The multiple antibiotics resistance indices of these isolates ranged from 0.5-0.8. The presence of these MBL producing bacteria in sachet water which are widely consumed is a potential threat to public health as the genes encoding MBL can be transferred to human commensals and pathogens. This could contribute to the failure in the use of carbapenems and other beta lactam antibiotics for treatment of infections.