Molecular characterisation of invasive <Emphasis Type="Italic">Streptococcus pyogenes</Emphasis> isolates from Hungary obtained in 2004 and 2005

Our aim was to characterise by molecular techniques group A streptococci isolated from invasive infections in Hungary in 2004–2005. Twenty-six nonduplicate invasive GAS isolates were selected and examined. The mortality rate proved high (52.3%) for those cases (n = 21) where data were available. Predominant emm types were emm1 (n = 13, 50%) and emm80 (n = 5, 19.2%), but other M types (emm4, emm28, emm66, emm81.1, emm82, emm84) were also identified. Eight different PFGE types were distinguished, and each emm type showed an individual PFGE pattern. Our results show that—similarly to results obtained in several other countries—emm type 1 strains predominate among invasive GAS isolates, and that emm 1 type strains recovered from severe streptococcal infections were associated with the presence of the speA gene. The rate for macrolide resistance proved low: only two isolates showed elevated MICs for erythromycin.     

emm gene diversity, superantigen gene profiles and presence of SlaA among clinical isolates of group A, C and G streptococci from western Norway

In order to investigate molecular characteristics of beta-hemolytic streptococcal isolates from western Norway, we analysed the entire emm gene sequences, obtained superantigen gene profiles and determined the prevalence of the gene encoding streptococcal phospholipase A2 (SlaA) of 165 non-invasive and 34 contemporary invasive group A, C and G streptococci (GAS, GCS and GGS). Among the 25 GAS and 26 GCS/GGS emm subtypes identified, only emm3.1 was significantly associated with invasive disease. M protein size variation within GAS and GCS/GGS emm types was frequently identified. Two non-invasive and one invasive GGS possessed emm genes that translated to truncated M proteins as a result of frameshift mutations. Results suggestive of recombinations between emm or emm-like gene segments were found in isolates of emm4 and stG485 types. One non-invasive GGS possessed speC, speG, speH, speI and smeZ, and another non-invasive GGS harboured SlaA. speA and SlaA were over-represented among invasive GAS, probably because they were associated with emm3. speG ^dys was identified in 83% of invasive and 63% of non-invasive GCS/GGS and correlated with certain emm subtypes. Our results indicate the invasive potential of isolates belonging to emm3, and show substantial emm gene diversity and possible lateral gene transfers in our streptococcal population.     

Distribution of emm types and subtypes among noninvasive group A, C and G streptococcal isolates in western Norway

Characterization of the reservoir of beta-hemolytic streptococci in a community may shed light on the pathogenesis of severe infections caused by these bacteria. We used emm sequence typing to characterize group A streptococci (GAS), group C streptococci (GCS) and group G streptococci (GGS) in community isolates associated with noninvasive disease in western Norway. A total of 165 isolates during a 13-month period were examined. Skin and throat isolates accounted for 123 and 16, respectively, and the remaining 26 isolates were from other non-sterile sites. We identified 18 previously validated emm types and one novel subtype, emm11.7, among the 101 GAS isolates. The two predominant types, emm28 and 12, were found in 40.6% of the GAS isolates. Compared to other recent studies of noninvasive GAS infections from elsewhere in the world, we found a higher frequency of emm82 (5.9%) and emm87 (12.9%) and a lower frequency of emm1 (4.0%) and emm3 (4.0%). We found a different distribution of GAS emm types compared to a previous study from western Norway. Among the 64 isolates of GCS and GGS, 15 previously described emm types and four novel subtypes, stC1400.5, stCK401.3, stG6.3 and stG652.3, were found, stG6, stG643 and stG485 were the most prevalent types and accounted for 59.4% of the GCS and GGS isolates. The high proportion of skin isolates in the present study may indicate the existence of GAS, GCS and GGS strains with predominantly skin and soft tissue tropism in our community.     

Group A streptococcal infection caused by <Emphasis Type="Italic">emm</Emphasis>1 strains among children in southern Taiwan

The aim of this study was to characterize the molecular epidemiology of invasive and non-invasive group A streptococcus (GAS) infections in children from 1997 through 2004 in southern Taiwan. A collection of 32 invasive and 150 non-invasive isolates were recruited for analysis. emm1 (34.4%) and emm12 (40.0%) predominated in the invasive and non-invasive isolates, respectively. The peak incidence of invasive GAS infection (IGASI) occurred between 2002 and 2003. emm4 and emm12 were the major types among clinical isolates before 2001, and was replaced by emm1 during 2002–2003. All emm1 isolates were clonal relatedness. The declined prevalence of erythromycin resistance occurred in the major shift of the endemic isolates to emm1 strains during 2002–2003 in the community. Financial support: the National Health Research Institute, Taiwan (NHRI-EX90∼EX92-9027SP), and the National Science Council, Taiwan (NSC93-2314-B-006-059).     

Invasive group A,C and G streptococcal disease in western Norway: virulence gene profiles,clinical features and outcomes

Invasive group A streptococcal (iGAS) disease is endemic in Norway, but data on invasive group C and group G streptococcal (iGCS/GGS) disease are lacking. We investigated the characteristics of iGAS and iGCS/GGS infections in western Norway from March 2006 to February 2009. Clinical information was retrospectively obtained from medical records. GAS and GCS/GGS isolates were emm typed and screened for the presence of 11 superantigen (SAg) genes and the gene encoding streptococcal phospholipase A₂ (SlaA). GCS/GGS isolates were also subjected to PCR with primers targeting speG^dys. Sixty iGAS and 50 iGCS/GGS cases were identified, corresponding to mean annual incidence rates of 5.0 per 100 000 and 4.1 per 100 000 inhabitants, respectively. Skin and soft tissue infections were the most frequent clinical manifestations of both iGAS and iGCS/GGS disease, and 14 iGAS patients (23%) developed necrotizing fasciitis. The 30-day case fatality rates of iGAS and iGCS/GGS disease were 10% and 2%, respectively. emm1, emm3 and emm28 accounted for 53% of the GAS isolates, and these types were associated with severe clinical outcome. SAg gene and SlaA profiles were conserved within most of the GAS emm types, although five profiles were obtained within isolates of emm28. stG643 was the most prevalent GCS/GGS emm type, and speG^dys was identified in 73% of the GCS/GGS isolates. Neither GAS SAg genes nor SlaA were detected in GCS/GGS. Our findings indicate a considerable burden of both iGAS and iGCS/GGS disease and a high frequency of necrotizing fasciitis caused by GAS in our community.     

Distribution of virulence factors and association with emm polymorphism or isolation site among beta‐hemolytic group G Streptococcus dysgalactiae subspecies equisimilis

Distribution of virulence factors and association with emm polymorphism or isolation site among beta‐hemolytic group G Streptococcus dysgalactiae subspecies equisimilis. Streptococcus dysgalactiae subspecies equisimilis (SDSE), the dominant human pathogenic species among group G streptococci, is the causative agent of several invasive and non‐invasive diseases worldwide. However, limited information is available about the distribution of virulence factors among SDSE isolates, or their association with emm types and the isolation sites. In this study, 246 beta‐hemolytic group G SDSE isolates collected in central Taiwan between February 2007 and August 2011 were under investigation. Of these, 66 isolates were obtained from normally sterile sites and 180 from non‐sterile sites. emm typing revealed 32 types, with the most prevalent one being stG10.0 (39.8%), followed by stG245.0 (15.4%), stG840.0 (12.2%), stG6.1 (7.7%), and stG652.0 (4.1%). The virulence genes lmb (encoding laminin‐binding protein), gapC (glyceraldehyde 3‐phosphate dehydrogenase), sagA (streptolysin S), and hylB (hyaluronidase) existed in all isolates. Also, 99.2% of the isolates possessed slo (streptolysin O) and scpA (C5a peptidase) genes. In addition, 72.8%, 14.6%, 9.4%, and 2.4% of the isolates possessed the genes ska (streptokinase), cbp (putative collagen‐binding protein, SDEG_1781), fbp (putative fibronectin‐binding protein, SDEG_0161), and sicG (streptococcal inhibitor of complement), respectively. The only superantigen gene detected was spegg (streptococcus pyrogenic exotoxin G^dys), which was possessed by 74.4% of the isolates; these isolates correlated with non‐sterile sites. Positive correlations were observed between the following emm types and virulence genes: stG10.0 and stG840.0 with spegg, stG6.1 and stG652.0 with ska, and stG840.0 with cbp. On the other hand, negative correlations were observed between the following: stG245.0, stG6.1, and stG652.0 types with spegg, stG10.0 with ska, and stG10.0, stG245.0, and stG6.1 types with cbp. The prevalence of emm types of SDSE in central Taiwan was investigated for the first time. Moreover, the distribution of virulence factors among beta‐hemolytic group G SDSE isolates, as well as their association with emm types or isolation sites were also examined.     

Sequence diversity of sicG among group C and G Streptococcus dysgalactiae subspecies equisimilis isolates associated with human infections in western Norway

Streptococcal inhibitor of complement (SIC) and distantly related to SIC (DRS) are well-characterized extracellular virulence factors produced by only a few emm types among group A streptococci. The prevalence and sequence variations of the sic-like gene (sicG) in clinical samples of group C and G Streptococcus dysgalactiae subspecies equisimilis (SDSE), however, have not been widely investigated. We constructed primers targeting sicG and screened 129 geographically matched and previously emm-typed non-invasive (n?=?64) and invasive (n?=?65) SDSE isolates for the presence of this gene. sicG was detected in seven non-invasive and eight invasive isolates belonging to eight different emm types. Within five of these emm types, sicG-negative isolates were also detected. All three isolates of stG2078.0 possessed sicG and were associated with severe soft tissue infections. Altogether, six sicG alleles (sicG1–6) were identified, and sequence variations were mainly caused by single nucleotide polymorphisms and deletion/insertion mutations. sicG1–6 were predicted to encode SICG proteins of varying length, composition, and homology with SIC and DRS proteins of group A streptococci. Our findings indicate an unpredictable association between sicG and emm type, a limited distribution and substantial sequence diversity of sicG, and no obvious relation between its presence and disease severity.     

Epidemiology and Molecular Characterization of Macrolide-Resistant Streptococcus pyogenes in Taiwan

Our multicenter nationwide surveillance data indicated that erythromycin (ERY) resistance among group A Streptococcus (GAS) isolates in Taiwan declined from 53.1% in 1998 and 2000 to 14.6% in 2002 and 2004 and 10.7% in 2006 to 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) isolates and 128 randomly selected ERY-susceptible (ERY^s) isolates recovered from 1998 to 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 (n = 33, 26.0%), emm12 (n = 24, 18.9%), emm4 (n = 21, 16.5%), and emm106 (n = 15, 11.8%). In ERY^s isolates, emm12 (n = 27, 21.9%), emm1 (n = 18, 14.1%), emm106 (n = 16, 12.5%), and emm11 (n = 9, 7.1%) predominated. The most common ERY resistance phenotype was the M phenotype (resistant to macrolides) (70.9%), with all but one isolate carrying mef(A), followed by the constitutive macrolide-lincosamide-streptogramin B resistance (cMLS_B) phenotype (26.8%), with isolates carrying erm(B) or erm(TR). ERY^r isolates of the emm12-sequence type 36 (ST36) lineage with the cMLS_B phenotype were mostly present before 2004, while those of the emm22-ST46 lineage with the M phenotype predominated in later years. Recovery from respiratory (throat swab) specimens was an independent factor associated with ERY resistance. emm1 and emm11 GAS isolates were significantly associated with ERY^s, while emm22 was detected only in ERY^r GAS. In addition, emm106 isolates were prevalent among the abscess/pus isolates, whereas emm12 isolates were strongly associated with a 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.     

Streptococcus pyogenes bacteraemia, emm types and superantigen profiles

The aim of this study was to investigate the emm types and superantigen profiles of bacteraemic group A streptococcal (GAS; Streptococcus pyogenes) isolates and to detect possible associations between the molecular characteristics of isolates and the clinical presentations of disease. In this population-based study, 87 bacteraemic GAS isolates from adult patients in Pirkanmaa Health District (HD), Finland, during the period 1995–2004 were emm typed and genotyped for superantigen (SAg) profiles. The epidemiological and clinical data of the patients were analysed with the microbiological characterisation data. Among the 87 isolates, 18 different emm types were found. emm1, emm28 and emm81 were the three most common types, covering 52% of isolates. The prevalence of specific emm types showed high variability during the 10-year study period. We could not find any association between the emm type and clinical features of bacteraemic infection, such as underlying diseases, disease manifestations or case fatality. Of nine superantigen genes examined, speA and speC were identified in 20 and 30% of the strains, respectively. No association was found between disease manifestation and the presence of single superantigen genes. The 26-valent GAS vaccine would have covered only 62% of isolates causing invasive disease in Pirkanmaa HD during the study period.     

Lateral genetic transfers between group A and G streptococci for M-like genes are ongoing

Previously we described a long-polymerase chain reaction (PCR) method to amplify a 4–7 kb target containing most of the components of the vir regulon (mga,emm-like genes andscpA) in a number of group A streptococcus (GAS) isolates.¹In contrast to GAS, strains of human group G streptococcus (GGS) gave approximately 1.6 or 1.8 kb products. Sequence analysis of the amplified products issued from GGS templates revealed a mosaic consisting of upstream sequence frommga(the gene for positive regulator of vir regulon), an unidentified open reading frame, a short segment ofemm(the gene for M protein, an antiphagocytic molecule) and an upstream sequence ofscp(C5a-peptidase gene). A full lengthscpGis present immediately downstream from the mosaic segment in the human GGS genome. The GGS PCR fragment did not code formgaor full lengthemm. All human GGS isolates are known to code foremmbut the gene is separated fromscpGby at least 10 kb.²Our data, obtained using long-PCR and unrelated strains of GGS, confirm this. We could not detect a homologue ofmgain human GGS by hybridization analysis. The mosaic sequence suggests that enbloc transfer of the vir regulon from GAS to a GGS progenitor may have occurred, following which deletion and rearrangement events may have taken place. Partial nucleotide sequences ofemmcorresponding to the variable domain of M proteins from three local GGS isolates were determined. One sequence (emmGGS6) is 99% identical toemmfrom a geographicaly separated isolate of GGS recently described.³emmGGS6 also has significant homology withemmfrom a GAS strain (STDONALD) isolated from the same geographical area as was GGS6. The twoemmsequences (emmGGS6 andemmSTDONALD) revealed frameshift-compensatory frameshift mutations relative to each other, contributing to lower amino acid homology between the two predicted M proteins. SinceemmSTDONALD has no known relatives within the 80 or soemmsequences in the database, we speculate that it could have been laterally acquired from GGS. Horizontal transfers between GGS and GAS may be ongoing.     

Adult Invasive and Noninvasive Infections Due to Streptococcus dysgalactiae subsp. equisimilis in France from 2006 to 2010

We characterized 182 Streptococcus dysgalactiae subsp. equisimilis isolates and analyzed the epidemiological data on the corresponding infections. stG6, stG485, and stG6792 were the 3 most prevalent invasive emm types among the 27 different emm types recovered. High rates of antimicrobial resistance were observed for macrolides (26.4%) and tetracycline (34.6%).     

Epidemiology, outcome and emm types of invasive group A streptococcal infections in Finland

In 2006, Finnish nationwide surveillance showed an increase of invasive group A streptococcal (iGAS) disease and clinicians were alarmed by severe disease manifestations, prompting the investigation of recent trends and outcome for iGAS. A case of iGAS was defined as Streptococcus pyogenes isolated from blood or cerebrospinal fluid. Cases during 1998–2007 and isolates during 2004–2007 were included. Case-patients’ 7-day outcome was available for 2004–2007. Isolates were emm typed. A total of 1,318 cases of iGAS were identified. The average annual incidence was 2.5/100,000 population. The rate was higher in males than females in persons aged 45–64 years, but lower in persons aged 25–34 years. The annual incidence was highest in 2007 (3.9/100,000). Occasional peaks occurred during midwinter and midsummer. The most common emm types were 28 (21%), 1 (16%), 84 (10%), 75 (7%) and 89 (6%). During 2004–2007, emm1 replaced emm28 as the most predominant type. The overall case fatality was 8%. Cases with emm1 were associated with high case fatality (14% vs. 8% in other types; p < 0.02); that of emm28 infections was 2% (p < 0.01). Changes in emm type prevalence influenced incidence and case fatality. Differences in age- and sex-specific incidence and seasonal patterns suggest variations in predisposing factors and underlying conditions.     

Streptococcus pyogenes emm Types and Clusters during a 7-Year Period (2007 to 2013) in Pharyngeal and Nonpharyngeal Pediatric Isolates

Group A streptococcus (GAS) is an important cause of morbidity and mortality worldwide. Surveillance of emm types has important implications, as it can provide baseline information for possible implementation of vaccination. A total of 1,349 GAS pediatric isolates were collected during a 7-year period (2007 to 2013); emm typing was completed for 1,282 pharyngeal (84%) or nonpharyngeal (16%) isolates, and emm clusters and temporal changes were analyzed. Thirty-five different emm types, including 14 subtypes, were identified. The most prevalent emm types identified were 1 (16.7%), 12 (13.6%), 77 (10.9%), 4 (10.8%), 28 (10.4%), 6 (6.8%), 3 (6.6%), and 89 (6.6%), accounting for 82.3% of total isolates. Rheumatogenic emm types comprised 16.3% of total isolates. The emm types 12, 4, and 77 were more prevalent among pharyngeal isolates, and the emm types 1, 89, 6, 75, and 11 were more prevalent among nonpharyngeal isolates. The emm types identified belonged to 13 emm clusters, and the 8 most prevalent clusters comprised 97% of all isolates. There were statistically significant decreases in the prevalence of emm types 12, 4, 5, and 61 and increases in the prevalence of emm types 89, 75, and 11, compared with the period 2001 to 2006. The proposed 30-valent GAS vaccine, which is currently in preclinical studies, encompasses 97.2% of the emm types detected in our study and 97.4% of the erythromycin-resistant strains. In addition, it includes 93.3% of the emm types involved in bacteremia. A much greater diversity of GAS emm types was identified in our area than described previously. Seasonal fluctuations and the introduction of new emm types were observed. Continuous surveillance of emm types is needed in order to evaluate the possible benefits of an M protein-based GAS vaccine.     

Different alleles of the fcrA/mrp gene of Streptococcus pyogenes encode M-related proteins exhibiting an identical immunoglobulin-binding pattern

  The majority of group A streptococci (GAS, Streptococcus pyogenes) express immunoglobulin (Ig)-binding proteins. The genes encoding these proteins belong either to the emm or the emm-related (fcrA/mrp and enn) gene family and are located in close proximity on the GAS genome, where they form part of the vir regulon. In the present study analysis of sequence data of the 5′ terminal portions of the fcrA/mrp genes from GAS isolates representing 37 different M serotypes led to a classification of six different types. Thus, although fcrA/mrp genes exhibit an allelic polymorphism, they do not display the high degree of N-terminal sequence diversity found among emm genes. The nucleotide sequences of the fcrA/mrp genes from 3 GAS isolates, belonging to serotypes M8, M9, and M13 and representing newly characterized fcrA/mrp gene types, are reported. Analysis of the Ig-binding properties of recombinant FcrA/Mrp8, 9, and 13 proteins, demonstrated a similar Ig-binding profile being reactive with human IgG subclasses 1, 2, and 4. This pattern is identical to that previously described for other recombinant fcrA/mrp4, 49, 64/14 and 76 gene products, indicating that this property is not affected by the N-terminal variability. Evidence for recombination between an fcrA/mrp and an mga gene was observed in an M-type 33 strain isolate providing further support for the concept of gene rearrangement contributing to the diversity of vir regulon gene products. Received: 31 January 1996     

Influence of azithromycin and clarithromycin on macrolide susceptibility of viridans streptococci from the oral cavity of healthy volunteers

Oral viridans streptococci are a reservoir of resistance genes for pathogens. Through prolonged exposure, long-acting macrolides (e.g., azithromycin) may induce the resistance of the commensals to macrolides more frequently than macrolides with a shorter half-life (e.g., clarithromycin). In a prospective, randomized, evaluator-blinded trial in healthy volunteers receiving standard courses of either azithromycin (n = 20) or clarithromycin (n = 20), we compared the susceptibility of oral viridans streptococci to macrolides over a period of 12 weeks. There was a significant temporal increase in the numbers of resistant isolates in both groups (p < 0.0005 at week 1). The proportion of macrolide-resistant isolates over time was significantly higher following azithromycin treatment (p = 0.0005), but returned to baseline values until week 12 in both groups. Temporal differential effects of azithromycin and clarithromycin on the induction of resistance were observed and need to be investigated regarding their effect on co-colonizing pathogens.     

Description of macrolide-resistant and potential virulent clones of Streptococcus pyogenes causing asymptomatic colonization during 2000–2006 in the Lisbon area

The asymptomatic oropharyngeal colonization rate by Streptococcus pyogenes was 10.7% in children (901 among 8,405 children 0–16 years old) and 3.3% in adults (37 among 1,126 households of children) in the Lisbon area during 2000–2006. Macrolide-resistant S. pyogenes from children (n = 149) was variable with time: 9.8–10.7% in 2000–2002, 28.1% in 2003, 19.6–2.7% in 2004–2005 and 14.6% in 2006. Eight lineages (97.3% of isolates) were identified based on at least 80% similarity of PFGE patterns, T types, emm types and multilocus sequence types (ST). The elevated frequency of macrolide resistance was associated with M phenotype lineages I (emm12/ST36) and V (emm4, emm75/ST39 and a novel emmstMrp6 type) and with one cMLS_B lineage IV (emm28/ST52) known to be associated with upper respiratory tract and invasive infections. Significant associations (p < 0.05) between emm type/virulence genotype were found, such as emm1/speA ⁺ ssa ^-, emm4/ssa ⁺ prtF1 ⁺, emm12/speA ^- ssa ^-. The high prevalence (>20%) of speC, prtF1 or ssa was probably caused either by clonal dissemination (speC), or to horizontal gene transfer events (prtF1 and ssa). This report contributes to a better understanding of the molecular epidemiology and evolution of macrolide-resistant S. pyogenes causing symptom-free oropharyngeal colonization. These colonizing strains carry macrolide resistance and virulence genes capable of being transferred to other bacterial species sharing the same niche.     

<Emphasis Type="Italic">Streptococcus pneumoniae</Emphasis> skin and soft tissue infections: characterization of causative strains and clinical illness

Streptococcus pneumoniae is an uncommon cause of skin and soft tissue infections, yet the incidence and clinical significance of its isolation in samples of skin or soft tissues in unselected hospital samples is poorly understood. In the present study, a review was conducted of the records of all patients with skin and soft tissue infections due to S. pneumoniae at a university hospital between January 1994 and December 2005. The isolates were identified by standard methods and were serotyped, and susceptibility testing was performed by the broth microdilution method following the guidelines of the Clinical and Laboratory Standards Institute. During the study period, 3,201 isolates of S. pneumoniae were recovered from several sources. Of these, 69 (2.2%) were from skin and soft tissue samples (69 patients). Complete information could not be obtained for 13 patients. Of the 56 patients remaining, 36 (64.3%) were infected and fulfilled the inclusion criteria. The following types of infections were observed: surgical wound infection (n = 11), burn infection (n = 7), pyomyositis (n = 6), cellulitis (n = 4), perineal or scrotal abscess (n = 3), and other (n = 5). Thirty-one (86%) patients had a favorable outcome, and 5 (13.8%) patients died. Mortality was directly attributable to S. pneumoniae infection in three of the five fatal cases. Of the 39 S. pneumoniae isolates obtained (36 from skin and soft tissues, three from blood cultures), 58.9% were penicillin nonsusceptible, 7.7% were cefotaxime nonsusceptible, and 20.5% were erythromycin resistant. The most frequent serotypes were 3, 19, 11, and 23. Of the overall number of isolates of S. pneumoniae recovered in a general institution, 2.2% involved skin and soft tissues (of which 64% were clinically significant). Mortality due to pneumococcal skin and soft tissue infections was low. R. Pallarés, coordinator (e-mail: rpallares@bell.ub.es)     

Prevalence of toxin genes in consecutive clinical isolates of <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> and clinical impact

Even if Panton–Valentine leukocidin (PVL), toxic shock syndrome toxin-1 (TSST-1), staphylococcal enterotoxins (SEB and SEC), and exfoliative toxins (ETA and ETB) may be associated with severe infections, the clinical significance of their presence in clinical isolates of Staphylococcus aureus remains poorly documented. In this study, we evaluated the prevalence of toxin genes and the relationship between their presence and the severity of infection. We screened for the presence of these six toxin genes among 186 consecutive S. aureus clinical isolates (resistant or not to methicillin) during a two-month period. We compared the toxin gene profile between strains recovered from patients presenting uncomplicated infections (n = 151) and from patients suffering from severe infections (n = 35). At least one toxin gene was detected in 55 (29.6%) isolates as follows: pvl (n = 1), tst + sec (n = 5), seb (n = 19), seb + sec (n = 1), sec (n = 28), and eta (n = 1). The proportion of toxin-producing strains among patients with uncomplicated infections (27.8%) and patients with severe infections (37.1%) was not statistically different (p = 0.3044), even if the severity of infection tended to be associated with the presence of sec (p = 0.0655). Although the prevalence of toxin genes was relatively high herein, no statistically significant association between the severity of infection and the presence of toxin genes was observed.     

Clinical aspects of invasive infections with Streptococcus dysgalactiae ssp. equisimilis in Japan: differences with respect to Streptococcus pyogenes and Streptococcus agalactiae infections

Streptococcus dysgalactiae ssp. equisimilis (SDSE) is increasingly being identified as a pathogen responsible for invasive and non-invasive infections. We compared the clinical features of invasive SDSE infections with those of invasive infections caused by Streptococcus pyogenes (group A streptococcus (GAS)) and Streptococcus agalactiae (group B streptococcus (GBS)). Active surveillance for invasive SDSE, GAS and GBS was maintained over 1 year at 142 medical institutions throughout Japan. Clinical information was collected together with isolates, which were characterized microbiologically. Two hundred and thirty-one invasive SDSE infections were identified, 97 other patients had infections with GAS, and 151 had infections with GBS. The median age of the SDSE patients was 75 years; 51% were male and 79% had underlying diseases. Forty-two SDSE patients (19%) presented to the emergency department. Among the 150 patients (65%) for whom follow-up was completed, 19 (13%) died and eight (5%) had post-infective sequelae (poor outcome). Insufficient white blood cell responses (<5000 cells/µL) and thrombocytopenia on admission each suggested significantly higher risk of poor outcome (ORs 3.6 and 4.5, respectively). Of 229 isolates, 55 (24%) showed an stG6792 emm type, which was significantly associated with poor outcome (OR 2.4). Clinical manifestations of invasive SDSE infections were distinct from those of invasive GBS infections. Primary-care doctors should consider invasive SDSE infections when treating elderly patients.     

Clinical presentations and epidemiology of β-haemolytic streptococcal bacteraemia: a population-based study

In this population-based study, all 314 episodes of β-haemolytic streptococcal bacteraemia in adult patients in the Pirkanmaa area, Finland, during the 10-year period 1995–2004 were retrospectively reviewed. Altogether, 92 cases of bacteraemia caused by Lancefield group A β-haemolytic streptococci (GAS), 76 caused by group B β-haemolytic streptococci (GBS), 18 caused by group C β-haemolytic streptococci (GCS) and 128 caused by group G β-haemolytic streptococci (GGS) were identified. The most important finding was that the incidence of GGS increased during the study period. Disruption of the cutaneous barrier was a very common predisposing factor in GAS and GGS bacteraemias. Skin infections were the presenting clinical manifestations in two-thirds of GAS and GGS bacteraemias.