Prevalence and molecular characteristics of methicillin-resistant Staphylococcus aureus among nasal carriage strains isolated from emergency department patients and healthcare workers in central Taiwan.

Screening and identification of methicillin-resistant Staphylococcus aureus (MRSA) carriage are helpful for controlling MRSA dissemination in hospitals. The aim of our study was to determine the prevalence of nasal carriages and diversity of MRSA among patients and healthcare workers (HCWs) at two regional hospitals in Taiwan. Nasal swabs were obtained prospectively from 204 patients visiting the emergency department (ED) and 326 HCWs in two regional hospitals in Changhua, Taiwan, between February 2015 and June 2015. All the MRSA isolates were further molecularly characterized. Of the 204 participating patients, the nasal carriage rates of S. aureus and MRSA were 22.1% and 7.8%, respectively. For HCWs, the S. aureus and MRSA carriage rates were 26.1% and 6.1%, respectively. There was no statistically significant difference in MRSA carriage rate between patients and HCWs (P = 0.447). Patients receiving hemodialysis were significantly associated with MRSA colonization (P = 0.012). The leading three sequence types (ST) were ST59 (16, 44.4%), ST45 (11, 30.6%), and ST239 (3, 8.3%) for all 36 MRSA isolates. ST59/SCCmec IV/t437/PVL-negative and ST45/SCCmec V/t1081/PVL-negative were the predominant clones among HCWs (30%) and participating patients (19%), respectively. Overall, a substantial proportion of patients visiting the ED and HCWs harbored CA-MRSA, mostly ST59 strains, in their nares. It is noteworthy that MRSA ST45 strains supplanted ST239 as the second leading nasal MRSA colonization strain in our study.

Wu TH ，Lee CY ，Yang HJ ，Fang YP ，Chang YF ，Tzeng SL ，Lu MC ... -  《-》

Nasal methicillin-resistant Staphylococcus aureus colonization among otherwise healthy children aged between 2 months and 5 years in northern Taiwan, 2005-2010.

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections have been increasingly reported worldwide and are associated with nasal colonization. In Taiwan, available data disclosed a similar trend. We conducted a study for the updated childhood nasal MRSA carriage. From July 2005 to December 2010, children aged between 2 months and 5 years who presented for a well-child health care visit to a medical center or from kindergarten/daycare center were invited and a nasal swab specimen was obtained for the detection of MRSA. All MRSA isolates were characterized. A total of 3226 children were included and the rate of nasal MRSA carriage was 10.2%. Children aged 2-6 months and >3 years were significantly associated with MRSA carriage, while pneumococcus colonization (p = 0.033) and breastfeeding (p = 0.025) were negatively associated with MRSA carriage. Of the 330 MRSA isolates, a total of 13 pulsotypes with two major patterns (type C, 47.0% and D, 29%) were identified. Most MRSA isolates belonged to two major clones, characterized as sequence type 59 (ST59)/pulsotype C/staphylococcal cassette chromosome (SCCmec) IV/Panton-Valentine leukocidin (PVL)-negative (45.8%) and ST59/pulsotype D/SCCmec VT/PVL-positive (22.7%). Two new clones as ST 508/SCCmec IV (9.7%) and ST573/SCCmec IV (7.3%) emerged and increased markedly since 2007. Between 2005 and 2010, 10.2% of healthy children in northern Taiwan carried MRSA in anterior nares, with the highest carriage rate for infants aged 2-6 months. Two emerging clones, ST 508 and ST 573, were identified and the clinical significance needs further surveillance.

Tsai MS ，Chen CJ ，Lin TY ，Huang YC ... -  《-》

Methicillin-resistant Staphylococcus aureus nasal carriage in international medical conference attendees.

Carriage of methicillin-resistant Staphylococcus aureus (MRSA) is associated with its transmission. International travels and massive gatherings may accelerate such transmission. MRSA carriage was surveyed among the attendees of two international medical conferences held in Taipei in 2010. A total of 209 attendees from 23 countries were recruited. Nasal specimens were collected from each volunteer and subjected to polymerase chain reaction (PCR) detection for MRSA. Molecular analysis, including pulsed-field gel electrophoresis, multilocus sequence typing (MLST), typing of staphylococcal cassette chromosome mec (SCCmec) and staphylococcal protein A (spa) genes, and detection of Panton-Valentine leukocidin (PVL) and sasX genes, was performed. MRSA carriage was detected in 10 (4.8%) attendees from Vietnam (3/8, 37.5%), Korea (2/6, 33.3%), Japan (2/41, 4.9%), Philippines (2/52, 3.8%), and Bangladesh (1/4, 25.0%). The proportion of MRSA colonizers was significantly higher in the local hospital group compared to those from the other groups (3/17 vs. 7/192, p < 0.05). Six MRSA isolates were available for molecular analysis. They all carried a type IV SCCmec gene. Five pulsotypes were identified; four genotypes, respectively, were identified by MLST and spa typing. None of the isolates carried either PVL or sasX genes. None of common molecular characteristics was shared by isolates from different countries. Most of these isolates were local endemic community clone in each country. As healthcare workers, a certain proportion of international medical conference attendees harbored MRSA in their nares, mostly local endemic community clones in each country, which has the potential of spread among attendees.

Huang YC ，Su LH ，Wu TL ，Lin TY ... -  《-》

Differences in Staphylococcus aureus nasal carriage and molecular characteristics among community residents and healthcare workers at Sun Yat-Sen University, Guangzhou, Southern China.

Chen B ，Dai X ，He B ，Pan K ，Li H ，Liu X ，Bao Y ，Lao W ，Wu X ，Yao Y ，Huang S ... -  《BMC INFECTIOUS DISEASES》

Nasal meticillin-resistant Staphylococcus aureus carriage among intensive care unit hospitalised adult patients in a Taiwanese medical centre: one time-point prevalence, molecular characteristics and risk factors for carriage.

From 25 June to 11 July 2008, a total of 177 adult patients hospitalised in an intensive care unit (ICU) (94 in medical ICUs and 83 in surgical ICUs) at a tertiary care hospital were screened for nasal carriage of meticillin-resistant Staphylococcus aureus (MRSA) by polymerase chain reaction. The overall prevalence of S. aureus and MRSA nasal carriage among the patients was 42% and 32%, respectively. MRSA carriage rate of the patients hospitalised in medical ICUs was significantly higher than that of those hospitalised in surgical ICUs (47% vs 16%, P<0.001). Multivariate logistic regression analysis revealed that pneumonia, chronic obstructive pulmonary disease, current MRSA infection, and medical ICU admission were independent predictors for nasal carriage of MRSA. Of the 38 MRSA isolates available for molecular analysis, a total of six pulsed-field gel electrophoresis (PFGE) patterns with two major patterns (F, 42%; A, 37%) were identified. Most MRSA isolates belonged to one of two major clones characterised as sequence type 5/PFGE F/staphylococcal cassette chromosome mec (SCCmec) II/Panton-Valentine leucocidin (PVL) genes negative (34%) and ST239/PFGE A/SCCmec III/PVL negative (26%), both clones being associated with healthcare-associated (HA) clones in Taiwan. Six isolates (16%) were characterised as ST59/SCCmec IV or V(T) and were associated with community strains in Taiwan. In conclusion, 32% of ICU hospitalised adult patients in a Taiwanese tertiary care teaching hospital between June and July 2008 were colonised with MRSA in their nares. Though most isolates were HA-MRSA, community strains accounted for a proportion of the isolates.

Chen CB ，Chang HC ，Huang YC 《-》