The Charactrization Antibiotic Susceptibility and Plasmid Profiles of Coagulase - Negative Staphylococci in Lagos

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Onubogu, C.C
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A total of 745 gram-positive, catalase-positive clustering cocci were obtained from various clinical specimens which included wound, blood, urine, catheter tips, high vaginal and endocervical swabs, urethral swabs, seminal fluids, bone secretions, eye and ear swabs. Thes isolates were obtained over an 18-month period from the Lagos University Teaching Hospital (LUTH), Idi-Araba, and General Hpspital, Ikeja. Swab samples were also obtained from skin, hands, axilla and nose of an apparently normal population and compared wtih isolated from clinical specimens. Isolation, and identification of coagulase-negative staphylococci (CoNS)were carried out using conventional methods. Characterisaction to species level was done using both conventional method and the APL rapid Commercial kit (ID 32 STAPH). The strains were tested for slime and beta-lactamase production. Other extracellular products tested for included DNase, lipase, protease, and gelatinase activities. Susceptibility to a range of antibiotics was tested and minimum inhibitory concentrations of some these antibiotics were determined. Some of these coagulase-negative staphylococci were screened for the presence of plasmids. A total of 244 isolates of coagulase-negative staphylococci were obtained, of which 241 were characterised to species level while 3 were unclassified. Staphylococcus epidermidis (109) was the most commonly isolated species from all the specimens. Comparing the conventional methods with the rapid commercial API kit (ID 32 STAPH), there was 98.8% specificity for the former and 95.9% specificity for the latter. A total of 40.50% were slime producers. Over one quarter (28.69%) of CoNS species showed lipase activity with greatest activity being shown by S. haemolyticus (54.17%). About 11.81% and 11% showed DNase and gelatinase activity respectively while 8.86% proteolytic activity. Betalactamase was detected in 69.5% of coagulase-negative staphylococci isolates. Majority of the isolates were multidrug-resistant to commonly used antibiotics. Some of the isolates harboured plasmids with molecuar weight ranging between 0.76 to 13.5 kilobase. Various findings reported in this study suggest that, coagulase-negative staphylococci can no longer be regarded as contaminants, but play a signirficant role in some infections in Lagos.
A Thesis Submitted to the School of Postgraduate Studies, University of Lagos
Antibiotics , coagulase-negative staphylococci , catalase-positive clustering cocci , Lagos University Teaching Hospital
Onubogu, C.C (1999). The Charactrization Antibiotic Susceptibility and Plasmid Profiles of Coagulase - Negative Staphylococci in Lagos. A Thesis Submitted to University of Lagos School of Postgraduate Studies Phd Thesis and Dissertation, 295pp.