Enzyme Production and Drug Resistance of Pseudomonas aeruginosa / 中华医院感染学杂志

OBJECTIVE To investigate the 16S rRNA methylases gene and AMEs of 30 strains multi-resistant Pseudomonas aeruginosa isolated from clinic work in our hospital.METHODS Collected 50 P.aeruginosa strains from two hospitals(30 strains of multi-resistant P.aeruginosa from Yantai,Shandong,20 strains of pan-drug resistant P.aeruginosa from Jiangsu),and analyzed 6 kinds of 16S rRNA methylases(armA,rmtA,rmtB,rmtC,rmtD and npmA) and 6 kinds of AMEs gene aac(3)-Ⅰ,aac(3)-Ⅱ,aac(6′)-Ⅰb,aac(6′)-Ⅱ,aac(3″)-Ⅰ,and aac(2″)-Ⅰ by PCR and sequence analysis.RESULTS Among 30 strains of multi-resistant P.aeruginosa from Yantai,the positive rate of 4 kinds of genes aac(3)-Ⅱ,aac(6′)-Ⅱ,aac(3″)-Ⅰ,and aac(2″)-Ⅰ was 20%(6/30),46.7%(14/30),36.7%(11/30) and 3.3%(1/30).The other 8 kinds genes were all negative.The total positive rate of AMEs gene was 46.7%(14/30).In 20 strains of pan-drug resistant P.aeruginosa,the positive rate of 6 kinds of genes rmtB,aac(3)-Ⅱ,aac(6′)-Ⅰb,aac(6′)-Ⅱ,aac(3″)-Ⅰ,and aac(2″)-Ⅰ was 55%(11/20),60%(12/20),35%(7/20),60%(12/20),50%(10/20) and 45%(9/20).The other 6 kinds genes were all negative.The total positive rate of AMEs gene was 95%(19/20).CONCLUSIONS It is the first report that 16S rRNA methylases gene is existed in P.aeruginosa;there is very high positive rate of AMEs genotypes in P.aeruginosa;there are differences in gene existing among two hospitals.

Antimicrobial Resistance of Streptococcus pneumoniae and Mechanisms of Resistance to Macrolides / 中华医院感染学杂志

OBJECTIVE To investigate the antimicrobial susceptibility of Streptococcus pneumoniae isolated in Yantai and their mechanisms of resistance to macrolides.METHODS Antimicrobial susceptibility of S.pneumoniae was determined by agar dilution method.Phenotypes of macrolide-resistant S.pneumoniae were determined using double disk test with erythromycin and clindamycin disks.ermB And mefE genes were amplified by PCR.RESULTS Among 42 strains of S.pneumoniae,65.0% were intermediate to and no strain was resistant to penicillin.The resistance rates to erythromycin and clindamycin were 93.0%,respectively.Of 41 erythromycin resistantstrains,93.0% were constitutive resistant.ermB Was detected in 40 strains and mefE in 1 strain,both ermB and mefE genes were found in 9 strains.CONCLUSIONS The resistance rate of S.pneumoniae to penicillin is high in Yantai area,the resistance rates to erythromycin and clindamycin are very high.Target modification by ermB methylase is the predominant mechanism in macrolide-resistant S.pneumoniae in Yantai.

Distribution and Resistance of Coagulase-negative Staphylococcus / 中华医院感染学杂志

OBJECTIVE To provide laboratory evidence for the prevention and control of coagulase negative staphylococcus(CNS),and study the distribution and drug resistance of CNS in our hospital.METHODS CNS of inpatients from Oct 2005 to Dec 2007 was isolated and identified with ATB Expression microbe identification and drug sensitivity system.RESULTS A total of 354 strains of CNS were isolated,from the main samples of secretion,sputum,blood and cerebrospinal fluld.The isolation rate from departments of pediatrics,ICU,orthopedics and neurology were 9.90%,9.30%,9.00% and 5.60%,respectively.CONCLUSIONS CNS is playing a significant role in nosocomial infection.The drug resistance of CNS is very serious.To pevent nosocomial infection,it is critically important to monitor the antimicriobial resistance of CNS and use autibiotics more rationally.