ABSTRACT
Aims: The ethanolic extracts of stem bark and fruit pulp as well as saponins from Dialium guineense were assayed for antibacterial activity against Gram positive and negative strains and clinical strains of methicilin resistant Staphylococcus aureus (MRSA) isolated from different locations on human body aged 20-30 years within the University of Nigeria community. Methodology: Agar diffusion technique was adopted. Results: The results showed that MRSA is predominant in apparently healthy population of the University community with 100% in males and 92.3% females showing positive case in nasal swab, 87.5% and 96.6 % positive from ear swabs of male and female volunteers respectively; and 77.7% positive from the high vaginal swabs of females. MRSA and other clinical isolates showed higher susceptibility to saponins compared to crude extracts; however, Bacillus cereus (NRRL 14724 and 14725) were not susceptible to the saponins from D. guineense. The MICs of the saponins were 31.25 mg/mL (B. subtilis ATCC 6051, P. aeruginosa, S. typhi, S. knitambo, P. mirabilis and S. aureus), 62.50 mg/mL (E. coli) and 125 mg/mL (P. aeruginosa ATCC 10145). Comparable MICs of higher values were obtained with the crude ethanolic extracts of stem bark and fruit pulp against MRSA and clinical isolates. Conclusion: The present findings revealed wide distribution of MRSA in an apparently healthy population in Nigeria and the susceptibility patterns showed the presence of a broad spectrum antibacterial agent in D. guineense.
ABSTRACT
BACKGROUND: Teicoplanin is a glycopeptide antimicrobial agent effective against methicillin-resistant staphylococci. Decreased susceptibility of staphylococci to glycopeptides has been increasing. Teicoplanin diffuses poorly in agar and therefore the correlation between the inhibition zone diameter and the minimal inhibitory concentration(MIC) is rather poor. The purpose of this study was to evaluate the prevalence of teicoplanin-resistant staphylococci and to assess the reliability of inhibition zone diameters for determining the susceptibility of staphylococci to teicoplanin by comparing the results of the agar dilution MICs. METHODS: From June to August 1997, 290 clinical isolates of staphylococci(77 coagulase negative staphylococci(CNS), 213 Staphylococcus aureus) were collected. The antimicrobial susceptibilities to teicoplanin were determined by inhibition zone diameter and the results were compared with the MICs determined by the agar dilution method. RESULTS: Among 77 CNS strains, 75(97.4%) were susceptible and 2(2.6%) were intermediate by agar dilution method and all 213 strains of S. aureus were susceptible to teicoplanin. There was a poor correlation(r=0.50) between the zone diameters of inhibition and agar dilution MICs. In comparison with the results of disk diffusion test and agar dilution MIC, eight (2.8%) out of 290 isolates showed discrepancies (major error rates : 0.3%, minor error rates: 2.4%). CONCLUSIONS: Two(2.6%) out of 77 strains of CNS and none of 213 S. aureus strains revealed decreased susceptibility to teicoplanin. And the inhibition zone diameter was less reliable in determining the susceptibility of staphylococci than MICs. Therefore, the more effective and convenient method is needed.
Subject(s)
Agar , Coagulase , Diffusion , Glycopeptides , Methicillin Resistance , Prevalence , Staphylococcus , TeicoplaninABSTRACT
Forty-Five cases of Shigellosis were treated with Ampicillin, TMP/SMX and Rifampin from April 1980. to November 1980. Of the 18 strains of shigellae, in-vitro sensitivity test was performed against twelve antimicrobial agents. The percentage of resistant strains was 77.8% in Ampicillin and 100% in TMP/SMX. Inhibition zone diameter by Rifampin disc was 8~10mm in all cases and clinical improvement with treatment was noted in nearly all cases, therefore we regarded inhibition zone diameter above 8mm sensitive to Rifampin. In clinical evaluation, the percentage of effectiveness by antibiotics was as follows; Ampicillin-60%, TMP/SMX-70% and Rifampin-93.3%. Rifampin appears to be the best, available drug bacteriologically and clinically for the treatment of Shilgellosis.