The aims of this study were to investigate any change in PCR ribotypes and to determine the antimicrobial resistance of common PCR ribotypes over a 10-year period in a tertiary care hospital. We conducted PCR ribotyping, antimicrobial susceptibility testing and DNA gyrase sequencing to identify changes in 1407 Clostridium difficile non-duplicated isolates obtained between 2000 and 2009. A total of 74 different ribotypes were found. The most prevalent ribotype was ribotype 001 (26.1 %). The prevalence of ribotype 017 was 17 % and that of ribotype 014/020 was 9.6 %. Ribotyping showed that the prevalence of ribotype 001 decreased and the prevalence of ribotypes 017, 014/020 and 018 increased over the 10 years. Antimicrobial resistance rates in prevalent ribotypes were: clindamycin, 81 %; cefotetan, 19 %; moxifloxacin, 42 %; imipenem, 8 %; ciprofloxacin, 100 % and erythromycin, 80 %. Ribotype 018 showed greater antimicrobial resistance than other ribotypes. All ribotype 018 strains showing moxifloxacin resistance had a substitution of a gyrA coding amino acid (Thr82 to Ile). This study will help the understanding of PCR ribotype trends and antimicrobial resistance of C. difficile in Korea.

PurposeEarly identification of causative agents in lower respiratory infection of pediatric patients can reduce morbidity and prevent an overuse of antimicrobials. Two kinds of multiplex polymerase chain reaction (PCR) and a commercial shell vial viral culture were performed to identify causative agents in pediatric patients.Materials and MethodsNasopharyngeal aspirates of 220 children diagnosed with viral pneumonia were obtained. Two kinds of multiplex PCR (Seeplex™ RV detection kit, and Labopass™ RV detection kit), and a shell vial culture by R-Mix were performed.ResultsPositive samples from 220 total samples by two multiplex PCRs were 52.7% and 46.4%, respectively. We also cultured 103 samples that showed positive results of the adenovirus, influenza virus, parainfluenza virus, and respiratory syncytial virus (RSV) by two multiplex PCR. The RSV was most frequently detected in 53.0% (Seeplex) and 51.7% (Labopass) of patients. The detection rate of adenovirus (AdV) was 10.3% and 12.1%, influenza virus (IFV) A and B was 12.5% and 3.4%, and parainfluenza virus (PIFV) 1, 2, and 3 were 2.9% and 2.6%. Shell vial cultures showed concordant results with each multiplex PCR by 96.1% and 77.7%, respectively. Sequencing results were 90% consistent with multiplex PCR.ConclusionMultiplex PCR showed more positivity than the shell vial culture and it can be an effective primary test. Other complementary efforts such as viral cultures and sequencing analysis could be considered, according to clinical and laboratory conditions.