Characterization of bacteria isolates colonizing the throat of hospitalized patients at Sobi Specialist Hospital, Ilorin, Nigeria and in vitro antimicrobial effects of Citrus aurantifolia and Alum on the isolates

1Olajide, O. A., *1Kolawole, O. M., 1Bada-Siyede, I. B., 1Ayanda, O. O., and 1,2Suleiman, M. M.

1Infectious Disease and Environmental Health Research Group, Department of Microbiology,  Faculty of Life Sciences, University of Ilorin, Nigeria                            2Department of Biological Sciences, College of Natural and Applied Sciences, Summit University, Offa, Nigeria *Correspondence to: [email protected]; [email protected]; +234-8060088495

Abstract:

Background: Antibiotic resistance in microorganisms implicated in nosocomial respiratory infections is a major reason for prolonged hospital stay and increased cost of therapeutic treatment of hospital acquired pneumonia (HAP). This study was designed to isolate bacterial pathogens colonizing the throat of hospitalized patients at the Sobi Specialist Hospital, Ilorin, and to evaluate antibacterial effects of extracts of Citrus aurantifolia peel and Alum against these bacterial isolates.

Methodology: This was a cross sectional study of 100 randomly recruited hospitalized patients at the Sobi Specialist

Hospital, Ilorin, Nigeria. Throat samples collected from consenting participants were cultured on selective agar media (MacConkey, Eosin-Methylene blue and Mannitol salt) for isolation of bacteria. Identification of isolates from culture plates was done by Gram reaction and conventional biochemical tests while confirmation of the isolates was done by the polymerase chain reaction (PCR) assay. Antibiotic susceptibility test for each isolate to selected antibiotics (ampicillin, amoxicillin-clavulanate, cefuroxime, ceftazidime, gentamicin, nitrofuran, ofloxacin and ciprofloxacin) was done by the Kirby Buer disc diffusion method. Aqueous extract of Alum ([KAl(SO4).12H2O]) was done to produce concentrations of 10, 20, 30, 40 and 50% (w/v) at pH 3.6 and tested on the bacterial isolates using agar diffusion method. Citrus aurantifolia peel was extracted using methanol and hexane solvents to produce extract concentrations of 500mg/ml, 250mg/ml and 150mg/ml, and tested on the isolates by agar diffusion, and by the broth dilution method to obtain minimum inhibitory (MIC) and minimum bactericidal concentrations (MBC) of C. aurantifolia

Results: A total of 14 bacterial isolates were recovered from throat samples of 100 hospitalized patients with Staphylococcus aureus (43%, n=6) being the most frequent while Escherichia coli (14.5%, n=2) was the least frequent. The isolates were generally resistant to penicillin, aminoglycoside and fluoroquinolone groups of antibiotics tested. The zone of inhibition for hexane and methanol extracts of C. aurantifolia and aqueous extract of alum on the bacterial isolates ranged from 11.5-19.2mm, 9.8-15.8mm, and 9.3-21.2mm respectively while those of selected antibiotics ranged from 7.0-25.0mm. The MICs of hexane and methanol extracts of C. aurantifolia against S. aureus were 10mg/ml and 25mg/ml, while the MBCs were 50 and 100mg/ml respectively.

Conclusion: Findings from this study showed the presence of resistant pathogenic bacteria colonizing the throat of hospitalized patients receiving care at the Sobi Specialist Hospital, Ilorin, Nigeria. The crude extracts of C. aurantifolia and Alum in this study showed inhibitory effects (albeit at higher concentrations) on the bacterial isolates comparable to the standard antibiotics. We posit that based on the inhibition capacity, further studies to characterize, purify and isolate the active anti-bacterial components in the extracts should be considered for novelty.

Keywords: Antibacterial; antibiotic resistance; Citrus aurantifolia; MBC; MIC.

Received Feb 4, 2022; Revised Apr 28, 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=”//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

Download full journal in PDF format below

Characterization of bacteria isolates colonizing the throat of hospitalized patients at Sobi Specialist Hospital, Ilorin, Nigeria and in vitro antimicrobial effects of Citrus aurantifolia and Alum on the isolates