Antibiotic susceptibility pattern of selected foodborne associated bacteria from cockroaches.
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Date
2024
Authors
Kapansa, Lawrence
Journal Title
Journal ISSN
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Publisher
The University of Zambia
Abstract
Cockroaches appear to be suitable mechanical transmitters for a wide range of food borne pathogenic microorganisms due to their habit of feeding on excreta or garbage and occurrence in places where food is stored or handled. Therefore, they can play a significant role in the dissemination of microorganisms between the environment. The objective of the study was to determine the antibiotic susceptibility pattern of selected bacterial food-borne pathogens isolated from cockroach species. A total of 278 cockroaches were collected from 50 rooms at University of Zambia and 40 houses in Kalingalinga between November 2023 and January 2024. Two species of cockroaches namely Periplaneta americana and Blattella germanica were identified using identification keys. The distribution of these species was found to be statistically insignificant between the two study sites, with B. germanica being more prevalent, accounting for 66.7% of the cockroaches at UNZA and 58.2% at Kalingalinga. Wash homogenates of the external and gut surfaces were used for culturing on selective and differential media. The isolated bacteria were identified using biochemical tests. Bacterial pathogens were isolated from both the external and gut surfaces of the cockroaches, with 39 foodborne-associated bacteria identified. These included Escherichia coli (12 isolates), Salmonella species (7 isolates), and Staphylococcus aureus (7 isolates) from P. americana, and from B. germanica, Escherichia coli (6 isolates), Salmonella species (3 isolates), and Staphylococcus aureus (4 isolates). Of the 39 bacterial isolates, 79% were from the cockroach gut, while 21% were from the external surface, showing that the gut is a significant reservoir for pathogenic bacteria. The distribution of these pathogens was not statistically significant across the study sites or cockroach body parts. Antibiotic susceptibility testing of the bacterial isolates revealed varying degrees of resistance. S. aureus showed high resistance to Penicillin G, while Salmonella and E. coli exhibited notable resistance to Ciprofloxacin and Cefotaxime, with 66.7% of all bacterial isolates being resistant to at least one class of antibiotics. Furthermore, 35.9% (N=39) of the isolates were multidrugresistant (MDR), with the MDR rate being 39% (n=18) in E. coli, 40% (n=10) in Salmonella and 27% (n=11) in S. aureus.
Phenotypic testing detected Extended Spectrum Beta-Lactamase (ESBL)-producing bacteria among the isolates, with 8 E. coli and 3 Salmonella identified as potential ESBL producers. After screening on Cefotaxime/MacConkey agar, 3 E. coli and 2 Salmonella were confirmed as ESBL producers. PCR analysis revealed the presence of blaCTX-M and blaTEM genes in these ESBLproducing isolates, with blaCTX-M detected in 2 E. coli isolates and blaTEM detected in all 5 ESBLproducing isolates. The findings from this study highlight the potential role of cockroaches as vectors for foodborne pathogens and multidrug-resistant bacteria in residential and institutional settings. Given the high percentage load of pathogenic bacteria, particularly in the gut of cockroaches, and the observed antimicrobial resistance, the results underscore the need for effective pest control strategies and prudent use of antibiotics to mitigate the spread of resistant bacteria. Moreover, the presence of ESBL-producing E. coli and Salmonella emphasizes the importance of ongoing surveillance of antimicrobial resistance in both healthcare and environmental contexts to protect public health.
Description
Thesis of Master of Science in One Health Laboratory Diagnostic Sciences.