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. aurantifoliaContinue reading “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”

Antibacterial activity and time kill kinetics of Amlodipine, Thioridazine and Promethazine against pathogenic clinical bacterial isolates

*1Akinjogunla, O. J., 2Umo, A. N., 3Alozie, M. F., 2Oshosanya, G. O., and 1Saturday, G. I.

1Department of Microbiology, University of Uyo, P.M.B. 1017, Uyo, Akwa Ibom State, Nigeria

2Department of Medical Microbiology and Parasitology, Faculty of Clinical Sciences, University of Uyo, Uyo, Akwa Ibom State, Nigeria

3Department of Pharmaceutical Microbiology and Biotechnology, Faculty of Pharmacy, University of Uyo, Uyo, Akwa Ibom State, Nigeria
*Correspondence to: [email protected]

Abstract:
Background: The emergence of multi-drug resistant bacterial strains worldwide has necessitated the scientific search for novel, potent, and affordable antimicrobial agents including medicinal plants and non-antibiotic drugs for therapy of infectious diseases. The objective of this study is to assess in vitro antibacterial activities and time kill kinetics of some non-antibiotic drugs against pathogenic clinical bacterial isolates.

Methodology: In vitro antibacterial activities including minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and time kill kinetics of Amlodipine (AML), Thioridazine (THI) and Promethazine (PRO) against Staphylococcus aureus, coagulase negative staphylococci (CoNS), Streptococcus spp, Escherichia coli, Enterobacter spp, Klebsiella pneumoniae and Pseudomonas aeruginosa clinical isolates were determined using disc diffusion, broth microdilution and plate count techniques.

Results: The mean growth inhibition zones by the disc diffusion assay of AML, THI and PRO against the isolates were ≤15.1±1.0 mm with MIC and MBC values ranging from 12.5 to 50μg/ml and 25 to 100μg/ml respectively. The time-kill assay revealed bactericidal effect of AML, THI and PRO on Gram positive bacteria evidenced by mean log reductions in viable bacterial cell counts ranging from 0.13 Log10 to 2.41 Log10 CFU/ml for S. aureus, 0.88 Log10 to 2.08 Log10 CFU/ml for Streptococcus spp, and 0.26 Log10 to 2.34 Log10 CFU/ml for CoNS after ≤30hrs post inoculation at 1xMIC. The range of log reduction in viable cell counts of Gram-negative bacteria exposed to AML, THI and PRO were E. coli (0.11 to 3.23 Log10 CFU/ml), P. aeruginosa (0.52 to 2.56 Log10 CFU/ml), K. pneumoniae (0.85 to 3.0 Log10 CFU/ml) and Enterobacter spp (0.38 to 2.08 Log10 CFU/ml) after ≤30 hrs post inoculation at 1x MIC.

Conclusion: These findings demonstrate in vitro antibacterial efficacies and time kill kinetics of AML, THI and PRO against pathogenic clinical bacterial isolates, which indicate that these non-antibiotic drugs may be useful therapeutic alternatives in the bid to reduce the burden of infectious diseases associated with antibiotic resistant pathogens.

Keywords: Amlodipine, Thioridazine, Promethazine, Time-Kill, Kinetics, MIC, MBC, bacteria

Received April 8, 2020; Revised July 12, 2020; Accepted July 13, 2020

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Editor-in-Chief: Prof. S. S. Taiwo

Activité antibactérienne et cinétique de destruction du temps de l’amlodipine, de la thioridazine et de la prométhazine contre les isolats bactériens cliniques pathogènes

*1Akinjogunla, O. J., 2Umo, A. N., 3Alozie, M. F., 2Oshosanya, G. O., et 1Saturday, G. I.

1Département de microbiologie, Université d’Uyo, P.M.B. 1017, Uyo, Akwa Ibom State, Nigéria

2Département de microbiologie médicale et de parasitologie, Faculté des sciences cliniques, Université d’Uyo, Uyo, État d’Akwa Ibom, Nigéria

3Département de microbiologie et biotechnologie pharmaceutiques, Faculté de pharmacie, Université d’Uyo, Uyo, État d’Akwa Ibom, Nigéria *Correspondance à: [email protected]

Abstrait:

Contexte: L’émergence de souches bactériennes multirésistantes dans le monde a rendu nécessaire la recherche scientifique d’agents antimicrobiens nouveaux, puissants et abordables, notamment des plantes médicinales et des médicaments non antibiotiques pour le traitement des maladies infectieuses. L’objectif de cette étude est d’évaluer les activités antibactériennes in vitro et la cinétique de destruction temporelle de certains médicaments non antibiotiques contre les isolats bactériens cliniques pathogènes.

Méthodologie: activités antibactériennes in vitro, y compris la concentration minimale inhibitrice (CMI), la concentration bactéricide minimale (MBC) et la cinétique de destruction du temps de l’amlodipine (AML), de la thioridazine (THI) et de la prométhazine (PRO) contre Staphylococcus aureus, les staphylocoques à coagulase négative (CoNS), Streptococcus spp, Escherichia coli, Enterobacter spp, Klebsiella pneumoniae et Pseudomonas aeruginosa ont été déterminés en utilisant des techniques de diffusion sur disque, de microdilution en bouillon et de numération sur plaque.

Résultats: Les zones moyennes d’inhibition de la croissance par le test de diffusion de disque d’AML, THI et PRO contre les isolats étaient ≤15,1±1,0mm avec des valeurs MIC et MBC allant de 12,5 à 50μg/ml et de 25 à 100μg/ml respectivement. Le dosage temporel a révélé un effet bactéricide de la LMA, du THI et du PRO sur les bactéries Gram positives, mis en évidence par des réductions logarithmiques moyennes du nombre de cellules bactériennes viables allant de 0,13 Log10 à 2,41 Log10 CFU/ml pour S. aureus, 0,88 Log10 à 2,08 Log10 CFU/ml pour Streptococcus spp et 0,26 Log10 à 2,34 Log10 CFU/ml pour CoNS après ≤ 30 heures après l’inoculation à 1 x MIC. La plage de réduction logarithmique du nombre de cellules viables de bactéries à Gram négatif exposées à la LMA, au THI et au PRO était E. coli (0,11 à 3,23 Log10 CFU/ml), P. aeruginosa (0,52 à 2,56 Log10 CFU/ml), K. pneumoniae (0,85 à 3,0 Log10 CFU/ml) et Enterobacter spp (0,38 à 2,08 Log10 CFU/ml) après ≤ 30 heures après l’inoculation à 1 x MIC.

Conclusion: Ces résultats démontrent une efficacité antibactérienne in vitro et une cinétique de destruction du temps des LMA, THI et PRO contre les isolats bactériens cliniques pathogènes, ce qui indique que ces médicaments non antibiotiques peuvent être des alternatives thérapeutiques utiles dans le but de réduire le fardeau des maladies infectieuses associées aux antibiotiques pathogènes résistants.

Mots-clés: Amlodipine, Thioridazine, Prométhazine, Time-Kill, Cinétique, MIC, MBC, bactéries

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Antibacterial activity and time kill kinetics of Amlodipine, Thioridazine and Promethazine against pathogenic clinical bacterial isolates

 

Antibacterial properties of Mangifera indica on Staphylococcus aureus

J Mushore, M Matuvhunye

 

Abstract

Antibacterial activity of Mangifera indica stem bark extracts was determined using disk diffusion, agar and broth dilution methods. In disk diffusion method, inhibition zone sizes were used to determine the susceptibility of S. aureus to the extracts. The results showed that the stem-bark extracts of M. indica have antimicrobial activity against S. aureus. Methanol extracts showed the highest inhibition zone diameter of 25 mm, followed by ethyl acetate, water and hexane extracts with inhibition zone diameter of 22 mm, 14 mm and 10 mm, respectively. The antibacterial activities of different extracts were found to be concentration dependent, in agar and broth dilution methods. The plant extracts were shown to have a MIC range of 0.62 mg/ml to 4.17 mg/ml, in agar dilution method. Results from the broth dilution method had a MIC range of 0.16 mg/ml to 1.25 mg/ml. The control (ampicillin) was however, more effective than plant extracts since only a concentration of 0.03 mg/ml in agar dilution and 0.001 mg/ml in broth dilution method were effective to inhibit the growth of S. aureus. The extracts were shown to be bacteriostatic at low concentrations. Phytochemical screening of the extracts revealed the presence of phyto-compounds such as alkaloids and tannins which are known to inhibit bacterial growth by different mechanisms from those of synthetic drugs. These phyto-constituents may be responsible for the M. indica antibacterial
activity.

Keywords: Staphylococcus aureus, antimicrobial activity, MIC, Phytochemical screening, MBC.

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Antibacterial properties of Mangifera indica on Staphylococcus aureus