Author : Michel Jean Massaad
Publisher :
ISBN 13 :
Total Pages : 194 pages
Book Rating : 4.:/5 (786 download)
Book Synopsis MRSA Molecular Typing by : Michel Jean Massaad
Download or read book MRSA Molecular Typing written by Michel Jean Massaad and published by . This book was released on 1996 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: Methici 11 in-resistant Staphylococcus aureus is now recognised as an important community and hospital acquired pathogen with serious morbidity, mortality, and health care cost in tertiary care centers and nursing homes (Araj etal., 1996; submitted). In this study, 32 MRSA isolates were typed according to their antibiotic susceptibility patterns, whole-cell protein profiles, as determined by SDS-PAGE, and their plasmid profiles. The relatedness of the isolates was assessed, and the validity of each typing method evaluated. Antimicrobial susceptibility testing of the 32 isolates against 16 antimicrobial agents was done using the disk diffusion method. Sixteen different susceptibility patterns were identified. All isolates (100%) were resistant to ampicillin, penicillin, and oxacillin. Sixteen isolates (50%) were resistant to tetracycline; 12 (37.5%) to clindamicin, erythromycin, and gentamicin; 10 (31.25%) to sulfamethoxazole - trimethoprim; 9 (28.1%) to augmentin, cephalothin, and imipenem; 6 (18.75%) to norfloxacin; 5 (15.6%) to pefloxacin; 3 (9.4%) to rifampicin; and 2 (6.25%) to nitrofurantoin. However, all the isolate were susceptible to vancomycin and fusidic acid. Protein analysis by SDS-PAGE of whole-cell protein showed a total of 50-69 protein bands which were dominated by 5 major band-clusters similar in all the isolates. Variations in minor bands were evident but the crowded protein profiles rendered qualitative analysis of the isolates difficult. Instead, numerical analysis of the protein patterns was used. Correlation studies revealed a degree of similarity of the isolates ranging between 74.1 and 100%. Overall, SDS-PAGE analysis of MRSA proved to be cumbersome and not highly informative as far as subtyping MRSA isolates. PPA revealed 17 different groups among the 32 MRSA isolates. The number of plasmids varied between i and 9. A 12 Kb and a 23 KB plasmids vi were most common among the isolates with 81.25% frequency for the former and a 31.25% frequency for the latter. In addition to that, 12 isolates which had similar antibiotic susceptibility patterns were further subdivided into 7 groups by PPA. This technique proved to be a valuable typing tool for MRSA, the results were reproducible, and the banding patterns easy to interpret. REAP was attempted on 4 isolates belonging to 2 different groups according to PPA. This resulted in further differentiating 1 of the 2 groups into 2 subgroups. Taken together, the data shows that the MRSA isolates in Lebanon are highly heterogeneous. Continued monitoring and typing, using both conventional methods and PPA, of new MRSA isolates is recommended.
