High incidence of multidrug-resistant strains of methicill inresistant Staphylococcus aureus isolated from clinical samples in Benin-City, Nigeria

Infections of methicillin-resistant Staphylococcus aureus (MRSA) are becoming an increasingly concerning clinical problem. The aim of this study was to assess the development of multidrug resistant strains of MRSA from clinical samples andpossibilities for reducing resistance. This study included a total of seventy-five (75) isolates comprising fifteen (15) each collected from ear, urine, cervix, blood and wounds. An agar disc diffusion test was used to measure the effects of antimicrobial agents against the bacteria isolates following  standardized guidelines. Out of a total of 75 clinical isolates of S. aureuscollected, 43 (57.3%) were resistant to methicillin with isolates obtained from ear infections showing the highest resistance pattern of 14.7% while the least was from urine sample with incidence of 5.3%. From the 43 isolates that showed resistance to methicillin, 36 (83.7%) were multidrug resistant to various classes of antibiotics tested.MRSA showed an increasing trend of antimicrobial resistance and therefore calls for periodic surveillance of nosocomial infections due to S. aureus and other important bacterial pathogens.Key Words: methicillin-resistant Staphylococcusaureus, MRSA, multidrug resistance, MD

Studies on the Genotoxic and Mutagenic Potentials of Mefloquine.

Purpose: The detection of mefloquine mutagenicity has not been achieved by the use of Salmonella typhimurium his TA1535, TA1537 as tester strains. With the introduction of improved and more sensitive strains, it is of interest to evaluate the current mutagenic and genotoxic status of the drug. This study presents data on the in-vitro mutagenic and genotoxic potentials of mefloquine hydrochloride clinically used as an antimalarial agent. Method: The mutagenicity potentials was investigated in the Escherichia coli WP2 trp and WP2 uvrA trp tester strains containing the plasmids, pEB017 and pKM101, and the Salmonella typhimurium TA97 containing pKM101. The genotoxicity potential was determined using the microscreen phage-induction assay. Results: The presence of plasmids pEBO17 and pKM101 enhanced the detection of mutagenicity of mefloquine. Microsomal-activated mefloquine unequivocally elicited base-pair substitution mutagenicity. The genotoxicity test indicated that mefloquine was generally not genotoxic but was of the same potential mutagenicity as chloroquine phosphate. Conclusion: Melfloquine hydrochloride exhibits base pair substitution mutagenesis, but not potentially genotoxic, even though it showed concentration dependent cytotoxicity. Its use as a last line antimalarial agent should still be encouraged. Keywords: Base-pair substitution, genotoxicity, mefloquine hydrochloride, mutagenicity, R-plasmid pEB017 Tropical Journal of Pharmaceutical Research 2002; 1(2):91-9

Prevalence of methicillin-resistant staphylococcus aureus among healthy residents of Ekosodin community in Benin-City, Nigeria

Purpose: To determine the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in apparently healthy residents of Ekosodin community, a peri-urban settlement, in Benin City, Nigeria.Method: Nasal swabs collected from 200 randomly selected individuals, aged between 16 and 38 years, were used in the study. Isolates from the swabs were aseptically collected and characterized using standard and established microbiological methods, which included growth and fermentation on mannitol salt agar (MSA), colonial morphology, Gram-staining reaction and biochemical tests. Antimicrobial susceptibility test was performed on Mueller-Hinton agar (MHA) by modified Kirby-Bauer disc diffusion method.Results: S. aureus was isolated in 49.5 % (n = 99) of the 200 nasal swabs. Among these isolates, 43 % were from male residents and 22.2 % (n = 22) were MRSA. The MRSA isolates indicated relatively high rate of resistance to penicillins, moderate resistance to erythromycin and cefuroxime, and leastresistance to gentamicin, streptomycin, ceftriaxone, ciprofloxacin and co-trimoxazole. There was no significant gender difference in terms of the colonization of S. aureus (p < 0.05).Conclusion: Many apparently healthy residents of Ekosodin community are nasal carriers of MSRA. The need for rational chemotherapy, routine detection and regular surveillance of MRSA to limit its spread and reduce treatment failures is vital

Antimicrobial and time-kill kinetics of the aqueous extract of Citrullus lanatus (Thunb.) seeds

This study evaluated the antimicrobial property of the aqueous extract of Citrullus lanatus (watermelon) seeds and its concentration-effect relationship (time-kill studies) on typed bacterial and fungal strains. Crude powdered seeds of Citrullus lanatus were extracted by maceration with water. Antimicrobial assay of the aqueous extracts was determined against Bacillus subtilis (NCTC 8236), Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 10145), Staphylococcus aureus (ATCC 25923), and Candida albicans (ATCC 24433) using standard microbiological methods. A total of 106 CFU/mL of each test strain was used as a baseline to carry out the time-kill studies. Extract concentration at minimum inhibitory concentration (MIC), 2MIC and 4MIC were used over a period of 24 hours. Aqueous extract had an intermediate antibacterial activity with inhibition zone diameters (IZD) of 15 - 18 mm and MIC range of 2.5 - 20 mg/mL. Time-kill studies showed a bacteriostatic, non-concentration dependent mode of antimicrobial activity with characteristic regrowth for all test strains. Citrullus lanatus seeds aqueous extract exhibited antimicrobial activity with a bacteriostatic, non-concentration dependent mode of action against test bacterial strains. Further studies aimed at isolating and purifying the antimicrobial principle in the aqueous extract of C. lanatus seed is warranted as this could serve as a potential new antibiotic for treating microbial infections

Microbiological and toxicological studies on cellulose generated from agricultural wastes

A pharmaceutical excipient is required to meet certain minimum standards for use in the manufacture of dosage forms. In this study, two of such requirements, microbiological and toxicological suitability, was investigated in respect of cellulose powder derived from an agricultural waste, maize cob.Microbial count data were obtained by inoculating a suspension of the cellulose into various types of agar. We also studied some of the possible toxicological effects of sub-acute ingestion of the cellulose in 2% tragacanth mucilage on adult male Wistar rats given 1.6 g/kg per day for 14 days. Weight changes, locomotor activity, some haematological parameters and the presence of gastrointestinal lesions were evaluated. Microbiological results indicate a ‘no growth’ status for yeast, fungi as well as for coliform and pseudomonas bacteria. The mesophilic bacterium, Bacillus subtilis returned a count of 100 cfu/g. Toxicological results show that animal weight was significantly (P < 0.05) reduced on the 14th day compared to weights on the 1st and 3rd days. Locomotor activity increased in a similar pattern being significantly higher (P < 0.05) on day 14 than on days 1 and 3. Platelet counts, white blood cell counts, and packed cell volume were not affected. There were no visible gastrointestinal (GI) lesions or morbidity and mortality in the animals. We conclude that the cellulose satisfied the BritishPharmacopoeia requirement for pharmaceutical grade starch that it should be free from the coliform bacterium, Escherichia coli. Furthermore, the results obtained showed that the cellulose neither exerted adverse effects on the haematological status of the animals nor is it associated with any other significant toxicological event

A preliminary study on the antimicrobial activities and gas chromatography-mass spectrometry (GC-MS) analysis of the ethyl acetate extract of Dennettia tripetala G. Baker seeds

The study investigated the antimicrobial properties and the chemical composition of ethyl acetate extract of Dennettia tripetala (pepper fruit) seeds. Crude extract obtained by maceration of pulverized seeds in ethyl acetate was evaluated for antimicrobial activity against Escherichia coli, Staphylococcus aureus, Klebsiella aerogenes, Pseudomonas aeruginosa, Bacillus subtilis, Candida albicans and Aspergillus niger using standard agar-well diffusion method. GC-MS method was used to determine the chemical constituents of the extract. The extract was oily, yellowish-brown with a yield of 1.66 % and had activity against most of the test microorganisms, with inhibition zone diameters ranging between 10 to 25 mm. About 41 chemical constituents were present in the extract with formic acid methyl esters and fatty acids accounting for 57.23 and 18.49 % respectively. Ethyl acetate extract of Dennettia tripetala seeds possessed antimicrobial activity against bacteria but not fungi. The observed activity may be due to the presence of formic and fatty acid esters in the seed. The study further established a scientific proof for the traditional use of Dennettia tripetala seed extracts in treating microbial infections. &nbsp

Antimicrobial activity of the ethanol extract and fractions of the seeds of Garcinia kola Heckel (Guttiferae)

The crude ethanol extract, aqueous and chloroform fractions of the seeds of Garcinia kola Heckel (Guttiferae) was investigated for antimicrobial activity. Agar well diffusion and minimum inhibitoryconcentration determinations were the methods employed for the study. Clinical bacterial and fungal isolates were used as indicator organisms while standard antimicrobial agents were included in thestudy. The crude ethanol extract showed significant inhibitory activity against clinical isolates of both Gram positive and Gram negative organisms. It was active against Staphylococcus aureus, Bacillussubtilis, Streptococcus viridans, Escherichia coli, Pseudomonas aeroginosa and Klebsiella pneumonia. It also showed significant inhibitory activity against fungi like Penicillium notatum, Aspergillus niger and Candida albicans. Both the aqueous and chloroform fractions showed activity against the clinical isolates of S. aureus, E. coli and P. aeruginosa. The MIC values obtained ranged between 2.5 and 7.5mg/ml for bacteria and fungi isolates. The results showed that the crude ethanol extract has broad spectrum of activity, while the fractions exhibited narrow spectrum of activity, since they were activeagainst S. aureus, E. coli, and P. aeruginosa only. These observations could be the basis for the usefulness of the seeds of G. kola in the treatment remedies for microbial infections

Health Status and Measurement of Some Haematological Parameters of New Secondary School Students in Benin City, Nigeria

Background: A good school health programme is necessary to optimize the educational opportunities and make appropriate adjustments for optimal development of the school child. This study was done to determine some haematological parameters as a correlate of health status of new entrants in two mission owned secondary schools in Benin City.Methodology: This is a cross-sectional study carried out among 150 students of two mission-owned secondary school in Benin City in which the packed cell volume, Rhesus factor, the Hemoglobin, genotype and blood group were analyzed.Results: Of the 150 students studied, 75.3% were males while 24.7% were females. The mean ages of the students were 10.5%EF%BF%BD 1.0yrs. Eighty-nine per cent of the students had a packed cell volume of between 33% and 42%. Ninety seven percent (96.7%) were rhesus D positive, 77.3% were of genotype AA, while 56.7% of them were of blood group O.Conclusion: Majority of the students were of good health status and had haematological profile similar to report of studies conducted elsewhere in Nigeria

Phytochemical and Antibacterial Evaluations of the Stem Bark of Newbouldia laevis against Isolates from Infected Wounds and Eyes

Purpose: To examine the phytochemical constituents and verify the ethnomedical claim of Newbouldia laevis (P.Beauv.) Seeman ex Bureau Bignoniaceae in treating septic wounds and eye problems. Methods: Applying standard methods, the phytochemical constituents of the stem bark were examined while the antibacterial potentials of the methanol extract of the stem bark and its organic solvent fractions were tested on clinical bacterial isolates from infected wounds and eyes using the agar -well diffusion method. Ciprofloxacin and gentamicin were used as standard controls. The time-kill kinetics of the methanol stem bark extract and ciprofloxacin were determined using isolates of Staphyloccocus aureus . Results: Phytochemical screening of the stem bark revealed the presence of flavonoids, tannins, saponins and alkaloids with no traces of cyanogenic glycosides. The 65 bacterial pathogens isolated included Proteus mirabilis (26.0 %) and Pseudomonas aeurginosa (17.4 %) from non-diabetic patients’ wounds; Staphylococcus aureus (32.0 %) and Escherichia coli (16.0%) from diabetic patients’ wounds; Staphylococcus aureus (35.3%) and Pseudomonas aeruginosa (35.3 %) from infected eyes. The chloroform fraction was observed to be more active on Gram-negative organisms while the aqueous fraction was more active on Gram-positive organisms. Time-kill kinetics of Staphylococcus aureus showed that the extract was bactericidal (99.9 % killing) at MIC and 2 x MIC after 24 and 3 hours, respectively. Conclusion: The study has established that the stem bark of Newbouldia laevis has antibacterial activities against bacterial isolates from infected wounds and eyes as claimed in ethnomedicinal practice