Study on mutation of pbp5 of ampidllin resistance in enterococcus faedum / 中华检验医学杂志

Objective To study the relationship of ampicillin resistance and?lactamase production, and gene mutation on pbp5 gene fragment in Enterococcus faecium. Methods?lactamase production was tested with nitrocefin, the pbp5 gene fragment of 57 isolates of ampicillin-resistant Enterococcus faecium (ARE. faecium) was amplified by PCR, the mutation of amplified pbp5 gene was detected by single-strand conformation polymorphism(SSCP), the specific mutation types were confirmed by sequencing. Results?lactamase was negative in 57 isolates of ARE. faeciums; there were 3-6 gene mutation sites on pbp5 gene fragment, and the frequent mutation sites were the position 485 ,499 and 466'. Conclusion The gene mutation of pbp5 gene fragment may play an important role in the ARE. faecium.

Prevalence of TEM- and SHV-type Beta-lactamase gene in Escherichia coli and Klebsiella pneumoniae in Korea / 감염

BACKGROUND: Resistance to beta-lactams in E. coli is mostly via acquisition of plasmid-mediated beta-lactamase gene. Among the plasmid-mediated beta-lactamases, TEM-1 beta-lactamase is by far the most prevalent among ampicillin-resistant E. coli. The prevalence of TEM-1 or TEM-2 ranged from 61% to 98% across the surveys. Klebsiella species generally have class A chromosomal beta-lactamases, which differ greatly from the class C types. Most K. pneumoniae isolates have chromosomally mediated SHV-1 beta-lactamase in most surveys. There has been only one report of prevalence and types of beta-lactamases in E. coli and K. pneumoniae in Korea. We performed this study to determine the prevalence and types of beta-lactamases in E. coli and K. pneumoniae isolated in Korea. METHODS: Ampicillin resistance was determined by disk diffusion test (E. coli) and agar dilution method (K. pneumoniae). Fifty five isolates of E. coli and 92 isolates of K. pneumoniae which were derived from patients in 2 university hospitals in Korea during 1996 were tested by TEM- and SHV-specific PCR. RESULTS: The ampicillin resistance rate in E. coli and K. pneumoniae was 82% and 94.6%, respectively. TEM-type beta-lactamase gene was found in 53% of E. coli isolates. 93.5% of K. pneumoniae isolates was found to have SHV-type beta- lactamase gene. CONCLUSION: In Korea TEM-type beta-lactamase gene was most prevalent in E. coli, but its prevalence rate was relatively low compared with those in other country. For K. pneumoniae, the isolates with SHV type beta-lactamase gene were predominant.