Antibiotic Resistant Bacteria From Fish Effluents Demonstrates Risk to Humans

Extended spectrum β-lactamases (ESBLs) can present major challenge to hospitals and health systems. These enzymes confer resistance to a high number of β-lactam antibiotics such as penicillin, cephalosporins, and monobactams.

In fact, Klebsiella has been associated with 2-5% of nosocomial infections, particularly urinary and respiratory tract infections.

In a poster presentation at IDWeek 2019, a team of investigators presented data on the detection of TEM, CTX-M and SHV genes which were collected through molecular characterization and typing. The study team is hopeful that this information about the bacteria can be useful in epidemiology and in determining risk factors associated with infections.

The authors explain that their objective was to conduct antibiotic susceptibility testing of both ESBL producing and non-ESBL producing Klebsiella species. Samples were collected from diarrheal stool, fish effluents, and well water and molecular characterization was carried out via polymerase chain reaction (PCR) and molecular typing was conducted by RAPD.

In total, 140 samples were collected, 50 from well water, 40 from fish effluents, and 80 from diarrheal stool samples. The team used the Kirby-Bauer disc diffusion method for antibiotic susceptibility testing and double disk diffusion test for phenotypic detection of ESBL enzymes.

The results indicate that 132 of the isolates were gram-negative, 38 (57.57%) Klebsiella spp. were isolated from fish effluents, 11 (57.89%) were isolated from well water and 15 (18.98%) were isolated from diarrheal stool samples. Additionally, 4 ESBL producers were isolated from stool (26.66%) and 12 were isolated from fish effluents (31.57%).

The investigators observed that stool isolates had high levels of resistance to ampicillin (86.7%), cefuroxime (83.3%), cefepime (76.7%) and ceftazidime (70%). On the other hand, fish effluents were more resistant to cefeperazone sulbactum (95.9%), and ampicillin (81.6%) while well water isolates showed high resistance to ampicillin (94.7%) and erythromycin (73.7%).

“Molecular identification showed presence of more than 2 genes among the isolates,” the authors wrote. They indicate further that the prevalence of gene bla- TEM was highest, followed by bla-CTX-M, and bla-SHV.

Based on these findings, the authors report that the study demonstrated a high prevalence of ESBL among Klebsiella isolates mainly from fish effluents and diarrheal stool samples. Overall, there was an ESBL positive rate of 24%. Additionally, this study found a high prevalence of TEM gene among Klebsiella species.

“Antibiotic resistant bacteria from fish effluents highlights the associated human health risk when they enter food chain and become passive carriers,” the authors write.

The study team concludes that routine ESBL testing with conventional antibiotic susceptibility testing can be helpful in combatting multidrug resistance.

The abstract, Molecular Typing by RAPD, Characterisation and Antibiotic Resistance profile of ESBL producing and Non ESBL Producing Klebsiella species isolated from Diarrheal stool and Environmental samples, was presented in a poster session on Thursday, October 3, 2019, at IDWeek 2019, in Washington DC.