Linfen, Shanxi, Methicillin-resistant Staphylococcus Aureus Resistance Protein A Gene Homology Analysis

Objective: To study the distribution and antibiotic resistance of methicillin-resistant staphylococcus aureus (MRSA) in clincal infections from Linfen district of ShanXi. To know the distribution of mecA gene in MRSA for providing reference to clinical rational use of antibiotics. The spa gene typing and sequence were used to analyze the characteristics of homology for predicting and preventing the infections of MRSAMetheds: (1) The API system of Biomerieux were used to identified the 196 strains of staphylococcus aureus from the three comprehensive hospitals in LinFen from 2009 June to 2010 June. The Kirby-Bauer method of cefoxitin and the mecA PCR were used to select MRSA. The antibiotic susceptibility of the MRSA isolates were performed by ATB Staph5 Stips . WHONET5.4 software was used to analyze the data. (2) The X-region of the spa gene was also amplified by PCR and the amplicons were directly analyzed by DNA sequencer. The spa types were determined with the database (http://spa.ridom.de/spaserver).Result: (1) Among 196 strains of staphylococcus aureus, 59 MRSA strains were isolated. The prevalence of MRSA was 30.1%. Of all the MRSA isolates, 36 were collected from ICU (35.6%), 19 from Neurosurgery (18.6%) , 10 from Burns surgery (16.9%), 7 from Pneumologyie (11.9%) etc. Most of the MRSA strains were isolated from sputum (59.3%) and the others from wound secretions (32.2%), etc. MRSA was resistant to more 90% of theβ-lactan,macrolides,quinolones,aminoglycosides,gentamicin,tetracycline,but quite sensitive to SMZ (84.8%) . The resistance rate of MRSA were clindamycin (83.1%),rifampicin (66.1%),minocycline (57.6%). No strains resistant to Vancomycin,Teicoplanin,Q.D and Nitrofurantion were found yet. There were 57 stains of MRSA with the mecA gene. The positive rate of mecA in MRSA strains was 96.6%. (2) t037 and t030 were the prevalent strain types respectively accounting for 69.5% (41/59) and 30.5% (26/59) of all MRSA strains.The Predominant spa type was t037. The t037 strains were distributied in ICU,Burns surgery,Neurosurgery and hospital acquired infection.Conclusion: (1) The isolating rate of MRSA from Staphylococcus aureus in Linfen was lower. The positive rate of mecA in MRSA is very high. MRSA has higher antibiotic resistant rate and more serious mult-drug resistance. The first selection of antibiotics were the Vancomycin,Teicoplanin,Q.D,Nitrofurantion and SMZ. (2) The t030 and t037 types of MRSA were spreading in LinFen regain. MRSA isolates types were mainly t037. MRSA strains from the three hospitals has the high homology. The same type of MRSA was be found in different clinical sections of the same hospital caused cross-infection probably.