Emergence of uncommon emm types of Streptococcus pyogenes among adult patients in southern Taiwan
ABSTRACT Streptococcus pyogenes isolated from adult patients during a 12-year period in southern Taiwan were analyzed to estimate the distribution of emm types and their correlation with disease manifestations and patient age.
Three hundred thirty-four invasive and noninvasive isolates collected from patients older than 20 years between 1997 and 2008 at National Cheng Kung University Hospital were included for emm typing. A correlation between emm type, disease manifestations, and patient ages was analyzed.
The nine most prevalent types were emm11, emm12, emm4, emm1, Sp9458/VT8, emm81, emm106, emm13, and emm75. Formerly rare emm types, including emm11, emm81, and emm102, emerged dramatically after 2004 in southern Taiwan. Type emm11 was significantly associated with both superficial infections and cellulitis. In addition, types emm13, emm81, and emm106 were more prevalent in patients older than 50 years and significantly associated with specific invasive disease manifestation.
These results suggest new emm types (emm11, emm81, and emm102) of S pyogenes were introduced into the adult population in southern Taiwan after 2004. The rarely reported emm types, including emm13, emm81, and emm106, caused invasive diseases more often in adult patients.
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ABSTRACT: Streptococcal toxic shock syndrome (STSS) is an uncommon but life-threatening disease caused by Streptococcus pyogenes. To understand the clinical and molecular characteristics of STSS, we analyzed clinical data and explored the emm types, superantigen genes, and pulsed-field gel electrophoresis of causative S. pyogenes isolates obtained between 2005 and 2012. In total, 53 patients with STSS were included in this study. The median age of the patients was 57 years (range: 9-83 years), and 81.1% were male. The most prevalent underlying disease was diabetes mellitus (45.3%). Skin and soft-tissue infection accounted for 86.8% of STSS. The overall mortality rate was 32.1%. Underlying diseases had no statistical impact on mortality. A total of 19 different emm types were identified. The most prevalent emm type was emm102 (18.9%), followed by emm11 (17%), emm1 (11.3%), emm87 (9.4%), and emm89 (7.5%). There was no statistically significant association between emm type and a fatal outcome. Among the superantigen genes, speB was the most frequently detected one (92.5%), followed by smeZ (90.6%), speG (81.1%), speC (39.6%), and speF (39.6%). The majority of emm102 strains were found to have speB, speC, speG, and smeZ. The presence of speG was negatively associated with a fatal outcome (P = 0.045). Our surveillance revealed the emergence of uncommon emm types, particularly emm102, causing STSS in southern Taiwan. Characterization of clinical, epidemiological, and molecular characteristics of STSS will improve our understanding of this life-threatening disease.PLoS ONE 12/2013; 8(12):e81700. DOI:10.1371/journal.pone.0081700 · 3.53 Impact Factor
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ABSTRACT: Our multicenter nationwide surveillance data indicated that erythromycin (ERY)-resistance among Group A Streptococcus (GAS) in Taiwan declined from 53.1% in 1998-2000 to 14.6% in 2002-2004 and 10.7% in 2006-2010 (p <0.01). The present study aimed to assess the epidemiology of GAS in Taiwan and identify factors associated with ERY-resistance. All 127 ERY-resistant (ERY-R) and 128 randomly selected ERY-susceptible (ERY-S) isolates from 1998-2010 were emm typed. ERY-R isolates were also characterized by ERY-resistance phenotype and mechanisms, and pulsed-field gel electrophoresis (PFGE). Multilocus sequence typing was performed on selected ERY-R isolates. The predominant emm types in ERY-R isolates were emm22 (33, 26.0%), emm12 (24, 18.9%), emm4 (21, 16.5%), and emm106 (15, 11.8%). In ERY-S isolates, emm12 (27, 21.9%), emm1 (18, 14.1%), emm106 (16, 12.5%), and emm11 (9, 7.1%) predominated. The most common ERY-resistance phenotype was M (70.9%) with all but one carrying mef(A), followed by cMLSB (26.8%) carrying erm(B) or erm(TR). ERY-R isolates of the emm12-ST36 lineage with the cMLSB phenotype was mostly present before 2004 while emm22-ST46 with the M phenotype predominated in later years. Recovery from respiratory (throat) specimens was an independent factor associated with ERY-resistance. The emm1 and emm11 isolates were significantly associated with ERY-S GAS while emm22 was detected only in ERY-R GAS. In addition, emm106 isolates were prevalent in abscess/pus isolates whereas emm12 isolates were strongly associated with respiratory (throat) origin. In addition to identifying factors associated with ERY-resistance in GAS, our study provides helpful information on the changing GAS epidemiology in Taiwan.Journal of clinical microbiology 12/2013; 52(2). DOI:10.1128/JCM.02383-13 · 4.23 Impact Factor
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ABSTRACT: Hyaluronic acid capsule is one of the most important virulence factors of group A Streptococcus (GAS). Over-production of capsule has been thought to enhance GAS virulence during infections. However, although the increased of capsule expression associates with increased bacterial virulence and invasive ability, over-production of capsule has not often been observed among clinical isolates. In the present study, we identified two mucoid emm12 type isolates that can convert to the hypermucoid morphology under both in vitro and in vivo conditions. Consistent with previous studies, hypermucoid variants are more invasive in the mouse air-pouch infection model. However, one of the hypermucoid variants showed a growth-defective phenotype in regular broth culture conditions and is significantly more susceptible to various DNA-damaging treatments when compared with the mucoid variant. These properties of the hypermucoid variant may be adverse factors inhibiting its adaptation to the host environment during infections.11/2013; 70(2). DOI:10.1111/2049-632X.12114