Concomitant genotyping revealed diverse spreading between methicillin-resistant Staphylococcus aureus and methicillin-susceptible Staphylococcus aureus in central Taiwan.

Staphylococcus aureus is a versatile bacterium, which can lead to various infectious diseases. Various molecular typing methods are applied to the evolution and epidemiology surveys of S. aureus, mostly for methicillin-resistant S. aureus (MRSA). However, methicillin-susceptible S. aureus (MSSA) is still an important pathogen, but their molecular typing is evaluated infrequently. Pulsed-field gel electrophoresis (PFGE), spa typing, and detection of five virulent genes for 95 MRSA and 56 MSSA isolates (July-December 2008 and July 2008-December 2009, respectively) during an overlapping period were performed. More diversity was found in MSSA isolates (23 pulsotypes and 25 spa types, excluding 4 new-type and 1 nontypable isolates for spa typing) than in MRSA isolates (19 pulsotypes and 16 spa types, excluding 1 new-type and 1 nontypable isolates for spa typing). By spa typing, t002 (n = 30), t037 (n = 23), t437 (n = 21), t234 (n = 3), t1081 (n = 3), and t1094 (n = 3) were the six major MRSA clones. For MSSA isolates, t189 (n = 13), t437 (n = 4), t084 (n = 3), t213 (n = 3), t701 (n = 3), and t7200 (n = 3) were the six major types. Combining PFGE and spa typing, there were five combinations (pulsotype + spa type) that contained both MRSA and MSSA isolates (pulsotype 9-t437, pulsotype 15-t037, pulsotype 19-t002, pulsotype 21-t002, and pulsotype 28-t1081). For all 151 S. aureus or 95 MRSA isolates, the PFGE typing had more discrimination power, but spa typing had larger discrimination index for 56 MSSA isolates. In conclusion, there were different predominant MRSA and MSSA clones clinically. Continuing longitudinal tracking of molecular typing is necessary for elucidating the evolution of this important clinical pathogen.

Ho CM ，Lin CY ，Ho MW ，Lin HC ，Peng CT ，Lu JJ ... -  《-》

[Infectivity-resistotype-genotype clustering of methicillin-resistant Staphylococcus aureus strains in the Central Blacksea Region of Turkey].

Kırca Yılmaz S ，Acuner IC ，Strommenger B ，Bek Y ，Witte W ... -  《MIKROBIYOLOJI BULTENI》

Epidemiology and molecular characteristics of community-associated methicillin-resistant and methicillin-susceptible Staphylococcus aureus from skin/soft tissue infections in a children's hospital in Beijing, China.

To evaluate the epidemiology and molecular features of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) and methicillin-sensitive S. aureus (MSSA) from children with skin and soft tissue infections (SSTIs) in Beijing, China, prospective community-acquired S. aureus SSTIs surveillance was conducted at the Beijing Children's Hospital, Beijing, China, for a 12-month period from August 1, 2008, to July 30, 2009. Susceptibility to 12 antimicrobials was determined by the agar dilution method. Genotypic characteristics of CA-MRSA isolates were tested by SCCmec typing, spa typing, and multilocus sequence typing. Panton-Valentine leukocidin gene was detected. Of 1104 cases, 31.8% (351) were community-acquired S. aureus. CA-MRSA accounted for 4% (14) of S. aureus. Among 14 CA-MRSA and 120 MSSA isolates tested, 100% and 91.7% were multidrug resistant, respectively. ST59-MRSA-IVa-t437 (42.9%) was the most common form of CA-MRSA. Spa typing analysis of 120 MSSA isolates was performed, followed by pulsed-field gel electrophoresis and multilocus sequence typing of a selected number of isolates. The most common spa types among MSSA were t084 (8.3%), t091 (5.8%), t034 (5%), t127 (4.2%), t002 (4.2%), and t796 (4.2%). No predominant spa type was seen. Of the MSSA isolates that could be classified into spa-CCs, 15.0% had a genetic background observed in CA-MRSA clones (spa-CC437, spa-CC342, and spa-CC377). Panton-Valentine Leukocidin (PVL)-positive community-acquired S. aureus strains were more commonly associated with skin abscesses than other SSTIs (29.4% versus 5.9%, P < 0.01).In conclusion, CA-MRSA infections are not common among Chinese children with SSTIs. Our findings show that MSSA strains in China have diverse genetic backgrounds.

Wu D ，Wang Q ，Yang Y ，Geng W ，Wang Q ，Yu S ，Yao K ，Yuan L ，Shen X ... -  《-》

Molecular characteristics of Staphylococcus aureus isolated from a major hospital in Lebanon.

The occurrence and dissemination of methicillin-resistant Staphylococcus aureus (MRSA) in healthcare settings and the community and its risk of being introduced into hospitals are matters of great concern. The purpose of this study was to conduct a miniaturized epidemiological analysis of S. aureus-associated infections and to characterize the isolates by a variety of molecular typing techniques. Ongoing molecular surveillance is essential to prevent S. aureus strains from becoming endemic in the Lebanese healthcare setting. A total of 132 S. aureus from different clinical specimens were isolated over a 6-month period. Characterization of the isolates was done by detection of the mecA gene, Panton-Valentine leukocidin determinant detection, staphylococcal chromosomal cassette (SCCmec) typing of MRSA, S. aureus protein A (spa) typing, multilocus sequence typing (MLST), pulsed-field gel electrophoresis (PFGE), and antibiogram analysis. MRSA represented 30% of the isolates, with PVL being detected in 54% of MRSA and 12% of methicillin-susceptible S. aureus (MSSA). A difference between MRSA and MSSA was observed in the spa types. Clustering SCCmec with MLST identified seven MRSA and 20 MSSA clones, with PVL-positive ST80-MRSA-IV being the dominant clone (7%), while PFGE revealed 32 groups with 80% cutoff similarity. Although the results of this study are based on samples collected from one hospital, the high diversity observed along with the lack of any equivalence in the genetic backgrounds of the major MSSA and MRSA clones, emphasizes the urgent need for standardized surveillance combined with the application of well-validated typing methods to assess the occurrence of MRSA and subsequently to control its spread.

Harastani HH ，Araj GF ，Tokajian ST 《-》

Molecular characteristics of Staphylococcus aureus isolates from food surveillance in southwest China.

Liao F ，Gu W ，Yang Z ，Mo Z ，Fan L ，Guo Y ，Fu X ，Xu W ，Li C ，Dai J ... -  《BMC MICROBIOLOGY》