Clonal spread of SCCmec type IV methicillin-resistant Staphylococcus aureus between community and hospital

ABSTRACTThe staphylococcal chromosome cassette (SCC)mec types of 382 hospital-acquired methicillin-resistant Staphylococcus aureus (HA-MRSA) isolates in Taiwan were analysed over a 7-year period (1999–2005). There was an abrupt increase in SCCmec type IV in HA-MRSA during 2005. The molecular epidemiology of a subset (n = 69) of HA-MRSA isolates with SCCmec types III, IV or V was characterised and compared with that of community-acquired MRSA (CA-MRSA) (n = 26, collected during 2005). Pulsed-field gel electrophoresis revealed three major pulsotypes (A, B and C) and 15 minor clones. Pulsotypes B and C, which contained isolates carrying SCCmec types IV and V, respectively, included both CA-MRSA and HA-MRSA isolates. Among 24 toxin genes analysed, five genes had significant differential distribution between CA-MRSA and SCCmec type III HA-MRSA. Furthermore, among SCCmec type IV isolates, the seb gene was detected more commonly in HA-MRSA. Analysis of representative members of the three major pulsotypes by multilocus sequence typing revealed two sequence types (STs), namely ST239 (SCCmec III) and ST59 (SCCmec IV or SCCmec V). This suggests that ST59:SCCmec IV, which is usually community-acquired, has become an important nosocomial pathogen in the hospital studied

A Persistent and Diverse Airway Microbiota Present during Chronic Obstructive Pulmonary Disease Exacerbations

Acute exacerbations of chronic obstructive pulmonary disease (COPD) are a major source of morbidity and contribute significantly to healthcare costs. Although bacterial infections are implicated in nearly 50% of exacerbations, only a handful of pathogens have been consistently identified in COPD airways, primarily by culture-based methods, and the bacterial microbiota in acute exacerbations remains largely uncharacterized. The aim of this study was to comprehensively profile airway bacterial communities using a culture-independent microarray, the 16S rRNA PhyloChip, of a cohort of COPD patients requiring ventilatory support and antibiotic therapy for exacerbation-related respiratory failure. PhyloChip analysis revealed the presence of over 1,200 bacterial taxa representing 140 distinct families, many previously undetected in airway diseases; bacterial community composition was strongly influenced by the duration of intubation. A core community of 75 taxa was detected in all patients, many of which are known pathogens. Bacterial community diversity in COPD airways is substantially greater than previously recognized and includes a number of potential pathogens detected in the setting of antibiotic exposure. Comprehensive assessment of the COPD airway microbiota using high-throughput, culture-independent methods may prove key to understanding the relationships between airway bacterial colonization, acute exacerbation, and clinical outcomes in this and other chronic inflammatory airway diseases