Assessment of microbial quality and detection of extended spectrum β-lactamase genes in Gram-negative bacterial isolates of herbal mixtures commonly hawked in Sagamu metropolis, Ogun State, Nigeria

*1Olaniran, O. B., 1Ajayi, S. E., 2Oluwatobi, O. B., and 2Adeleke, O. E.

1Department of Pharmaceutical Microbiology, Faculty of Pharmacy, Olabisi Onabanjo University,

Sagamu, Ogun State, Nigeria                                                                              2Department of Pharmaceutical Microbiology, Faculty of Pharmacy, University of Ibadan, Ibadan, Nigeria

*Correspondence to: [email protected]

Abstract:

 

Background: The use of herbal mixtures in the treatment of diseases is on the rise. Many of these herbal drugs are not produced under hygienic conditions and safety issues associated with herbal medicines may have an exacerbated impact in immunocompromised and elderly individuals. This study aimed to determine the microbial loads of locally prepared herbal mixtures and detect extended spectrum beta-lactamase (ESBL) genes in any isolated Gram-negative bacteria pathogen.

Methodology: Fifty local herbal mixtures were purchased randomly from three locations in Sagamu town (Sagamu market, Ita-Oba Road and Isale Oko) in Ogun State, Nigeria. The mean total viable bacterial (MTVB), mean total coliform (MTC), and mean total fungal (MTF) counts were determined by the plate count method. The bacterial isolates were streaked on differential bacteriological media while the fungi isolates were grown on potato dextrose agar. The isolates were identified upon growth on culture media using conventional biochemical tests. Antibiotic susceptibility pattern of the isolates was determined using Kirby-Bauer disk diffusion technique. Phenotypic detection of ESBL was done by the modified double disc synergy test followed by amplification detection of blaTEM, blaCTX-M and blaSHV genes with polymerase chain reaction (PCR) assay.

Results: Bacteria and fungi were isolated from 38 (76.0%) and 25 (50.0%) of the herbal samples respectively. Ten (20.0%) and 14 (28.0%) of the samples had mean bacterial and fungal load that exceeded 105CFU/mL or g, respectively. Nineteen (38.0%) of the herbal samples analyzed had total coliforms. Fifty-one isolates belonging to eight bacterial genera and 28 fungi isolates belonging to four fungal genera were obtained. Thirty-two (62.7%) of the bacterial isolates were Gram-negative while 19 (37.3%) isolates were Gram-positive. Staphylococcus aureus was the most common bacterial isolate (33.3%) while Aspergillus species was the most prevalent fungus (60.7%). Sixteen (84.2%) S. aureus and 26 (81.3%) Gram-negative isolates were multidrug resistant, and 6 (18.8%) of 32 Gram-negative isolates were ESBL producers. ESBL-encoding genes were detected in 7 (27%) of the 26 multidrug resistant Gram-negative bacteria with TEM and SHV being the most prevalent 4 (14.8%) while CTX-M was identified in only one isolate.

Conclusion: This study reported the presence of microbial contaminants which exceeded the safety limits of 105 CFU/g according to World Health Organization. The use of locally prepared herbal medicines poses a major health risk due to the lack of microbial quality standards.

Keywords: Herbal medicines, Gram-negative bacteria, extended spectrum beta-lactamase, microbial contaminant

Received Feb 18, 2022; Revised Apr 26, 2022; Accepted May 02, 2022

Copyright 2022 AJCEM Open Access. This article is licensed and distributed under the terms of the Creative Commons Attrition 4.0 International License <a rel=”license” href=”http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, distribution and reproduction in any medium, provided credit is given to the original author(s) and the source. Editor-in-Chief: Prof. S. S. Taiwo

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Assessment of microbial quality and detection of extended spectrum β-lactamase genes in Gram-negative bacterial isolates of herbal mixtures commonly hawked in Sagamu metropolis, Ogun State, Nigeria