Search

BackgroundEarly-onset neonatal sepsis (EOS) is a rare condition but an important cause of severe morbidity and mortality in neonates.MethodsThis is a prospective observational study in neonates born at ≥34 weeks of gestation (WG). The primary endpoint was EOS, defined by isolation of pathogenic species from blood culture and/or cerebrospinal fluid culture within 72 hours after birth. Data on EOS were collected exhaustively from all maternity wards in Paris area (April 2019–March 2021).Results108 EOS were recorded (annual incidence, 0.32 per 1000 live births; 95% CI 0.26 to 0.38). In term infants, the most frequent pathogens were group BStreptococcus(GBS) (n=47) andEscherichia coli(n=20); in late preterm infants, the most frequent pathogens wereE. coli(n=15) and GBS (n=7). Fifteen meningitis cases were diagnosed. FiveE. colistrains (14%) were resistant to both amoxicillin and gentamicin, which is an empiric treatment for EOS. Of the 54 infants with GBS infections, 35 were born from mothers with negative GBS prepartum screening test and 8 from mothers with no screening. Two deaths were reported, both in term infants (Proteus mirabilisandE. coli).ConclusionIn neonates ≥34 WG born in the Paris area, GBS was twice as frequent asE. coliin term infants. EOS was six times more frequent in late preterm than in term infants and was due toE. coliin 60% of cases. Prevention of GBS EOS and empiric antibiotic treatment of EOS could be improved.

Streptococcus pyogenes , also known as group A Streptococcus , causes a wide variety of diseases, leading to 517,000 deaths yearly. The two-component CovRS system, which responds to MgCl 2 and the antimicrobial peptide LL-37, controls the expression of 15% of the genome.

To investigate Group B Streptococcus (GBS) colonization in pregnancy; adherence to antenatal GBS screening and adherence to the intrapartum antibiotics protocol within two models of care (midwifery and non-midwifery led).This retrospective quantitative study has employed a descriptive design using administrative health data.Data from five maternity hospitals in metropolitan and regional Western Australia that included 22,417 pregnant women who gave birth between 2015 and 2019 were examined, applying descriptive statistics using secondary data analysis.The study revealed an overall GBS colonization rate of 21.7% with similar rates in the different cohorts. A lower adherence to screening was found in the midwifery led model of care (MMC, 68.76%, n = 7232) when compared with the non-midwifery led model of care (NMMC, 90.49%, n = 10,767). Over the 5 years, screening rates trended down in the MMC with stable numbers in the counterpart. Adherence in relation to intrapartum antibiotic prophylaxis revealed discrepant findings between the study groups.Adherence to screening and management guidelines of maternal GBS colonization in pregnancy is lower within the MMC when compared with the NMMC.This is the first cohort study to describe the adherence to the recommended Western Australian GBS screening guidelines in the two different models of care. Findings may assist in the guidance and improvement of clinical protocols as well as the planning of clinical care in relation to GBS screening to reduce the risk of neonatal GBS infection.

To identify factors associated with vaginal colonization and persistence by group B Streptococcus (GBS) and by the hypervirulent neonatal CC-17 clone in late pregnancy and after delivery, a multicentre prospective observational cohort with 3-month follow-up was established in two university hospitals, Paris area, France. Pregnant women were recruited when antenatal screening for GBS vaginal colonization at 34–38 weeks of gestational age was positive. Vaginal samples were analysed by conventional culture methods at antenatal screening, delivery, and 21 and 60 days following delivery. Identification of the hypervirulent neonatal GBS CC-17 was performed. Colonization was defined as persistent when all vaginal samples were positive for GBS. A total of 754 women were included. GBS vaginal colonization was persistent in 63% of the cases (95% CI 59%–67%). Persistent colonization was more likely in women born in Sub-Saharan Africa compared with women born in France (OR = 1.88, 95% CI 1.05–3.52), and GBS CC-17 was overrepresented in women born in Sub-Saharan Africa (OR = 2.09, 95% CI 1.20–3.57). Women born in Sub-Saharan Africa are at higher risk for GBS vaginal persistence than women born in France. This observation correlates with an increased prevalence of the hypervirulent GBS CC-17 in the former group, which likely reflect variations linked to ethnicity and vaginal community-state types and might account for the increased susceptibility of black neonates to GBS infections.

Group B Streptococcus (GBS) is the leading cause of neonatal infections and an important pathogen in pregnancy. However, the features of pregnancy-associated infections are poorly reported. We analyzed 336 cases of GBS invasive infections in women aged 18–50 years, including 242 (72.0%) pregnancy-associated infections. In pregnancy, most cases were intra-amniotic infections (55.8%), occurred preterm (61.3%), and were associated with obstetrical and neonatal complications (81.7%). The GBS clone CC-17 (18.8% of the cases) was overrepresented intrapartum (35.2%; odds ratio, 5.1 [95% confidence interval, 1.6–19.3]). This work highlights the burden of GBS and of the CC-17 clone infections during pregnancy.

International audience; Streptococcus agalactiae (group B Streptococcus, GBS) remains the leading cause of invasive diseases in neonates and an important cause of infections in the elderly. The aim of this study was to access the prevalence of GBS genito-rectal colonisation of pregnant women and to evaluate the genetic characteristics of invasive and non-invasive GBS isolates recovered throughout Serbia. A total of 432 GBS isolates were tested for antimicrobial susceptibility, capsular polysaccharide (CPS) types and the presence of the hvgA gene. One hundred one randomly selected isolates were further characterized by clustered regularly interspaced short palindromic repeats (CRISPRs) analysis and/or multilocus sequence typing (MLST). The prevalence of GBS colonization in pregnant women was 15%. Overall, six capsular types (Ia, Ib, II to V) were identified, the most common being III (32.2%) and V (25.2%). The hiper-virulent clone type III/ST17 was present in 43.1% and 6.3% (p

Group A Streptococcus (GAS), a Gram-positive human-specific pathogen, yields 517,000 deaths annually worldwide, including 163,000 due to invasive infections and among them puerperal fever. Before efficient prophylactic measures were introduced, the mortality rate for mothers during childbirth was approximately 10%; puerperal fever still accounts for over 75,000 maternal deaths annually. Yet, little is known regarding the factors and mechanisms of GAS invasion and establishment in postpartum infection. We characterized the early steps of infection in an ex vivo infection model of the human decidua, the puerperal fever portal of entry. Coordinate analysis of GAS behavior and the immune response led us to demonstrate that (a) GAS growth was stimulated by tissue products; (b) GAS invaded tissue and killed approximately 50% of host cells within 2 hours, and these processes required SpeB protease and streptolysin O (SLO) activities, respectively; and (c) GAS impaired the tissue immune response. Immune impairment occurred both at the RNA level, with only partial induction of the innate immune response, and protein level, in an SLO- and SpeB-dependent manner. Our study indicates that efficient GAS invasion of the decidua and the restricted host immune response favored its propensity to develop rapid invasive infections in a gynecological-obstetrical context.

We analyzed group B Streptococcus (GBS) neonatal invasive infections reported during 2007–2019 in France. The hypervirulent clonal complex (CC) 17 GBS was responsible for 66% (827/1,262) of cases. The role of CC17 GBS increased over time (p for trend = 0.0001), together with the emergence of a multidrug-resistant CC17 GBS sublineage.

To identify factors associated with vaginal colonization and persistence by group B Streptococcus (GBS) and by the hypervirulent neonatal CC-17 clone in late pregnancy and after delivery, a multicentre prospective observational cohort with 3-month follow-up was established in two university hospitals, Paris area, France. Pregnant women were recruited when antenatal screening for GBS vaginal colonization at 34-38 weeks of gestational age was positive. Vaginal samples were analysed by conventional culture methods at antenatal screening, delivery, and 21 and 60 days following delivery. Identification of the hypervirulent neonatal GBS CC-17 was performed. Colonization was defined as persistent when all vaginal samples were positive for GBS. A total of 754 women were included. GBS vaginal colonization was persistent in 63% of the cases (95% CI 59%-67%). Persistent colonization was more likely in women born in Sub-Saharan Africa compared with women born in France (OR = 1.88, 95% CI 1.05-3.52), and GBS CC-17 was overrepresented in women born in Sub-Saharan Africa (OR = 2.09, 95% CI 1.20-3.57). Women born in Sub-Saharan Africa are at higher risk for GBS vaginal persistence than women born in France. This observation correlates with an increased prevalence of the hypervirulent GBS CC-17 in the former group, which likely reflect variations linked to ethnicity and vaginal community-state types and might account for the increased susceptibility of black neonates to GBS infections.

Group B Streptococcus (GBS) (Streptococcus agalactiae) is a pathogen of growing importance in adults. The objective of this study was to describe the features of invasive infections by GBS in non-pregnant adults.GBS infections were reported to the national reference centre for streptococci. Clinical information was abstracted from questionnaires. Capsular typing, identification of the hypervirulent CC-17 clone, and antibiotic susceptibility testing were performed for all GBS isolates. Multi-locus sequence typing and assignment to clonal complexes (CCs) was performed on a representative sample of 324 isolates.In total, 1960 GBS invasive infections were analysed from 2007 to 2019. The median age at onset was 71 years old (range 18-103). The main manifestation was bacteraemia without focus (54.5%). Meningitis was more frequent in patients under 40 (26/180, 14.4% versus 78/1780, 4.4%, p 0.0001). Capsular types Ia, Ib, II, III and V accounted for 91.0% of the cases (1786/1960). CC-1, -10, -17, -19 and -23 accounted for 96.3% (312/324) of the cases. Capsular type III and CC-17 were overrepresented in meningitis (38/104, 36.5%, p 0.001 and 22/104, 21.2%, p 0.01, respectively). All isolates were susceptible to β-lactam antibiotics. Resistance to erythromycin (32.7%) and clindamycin (26.3%) remained stable, whereas decreased susceptibility to fluoroquinolones increased, reaching 2.7% in 2019 (p for trend 0.002).This work highlights the susceptibility of the elderly to GBS infections and differences in the clinical manifestations according to the patients' age and GBS type. In agreement with worldwide reports on emerging multidrug-resistant GBS, it reinforces the need for a continued surveillance of GBS epidemiology.

International audience; An outbreak of nosocomial infections due to Streptococcus pyogenes (Group A Streptococcus; GAS) occurred in a post-surgery oncology unit and concerned more than 60 patients and lasted 20 months despite enhanced infection control and prophylaxis measures. All GAS strains were characterized (emm genotype, toxin gene profile and pulse-field gel electrophoresis subtype). Selected strains were sequenced and phylogenetic relationship established. Capacity to form biofilm and interaction with human pulmonary epithelial cells and macrophages were determined. Twenty-six GAS strains responsible for invasive infections (II) and 57 for non-II or colonization were isolated from patients (n = 66) or healthcare workers (n = 13). Seventy strains shared the same molecular markers and 69 the same PFGE pattern; 56 were sequenced. They all belonged to the emerging emm89 clade 3; all but 1 were clonal. Whole genome sequencing identified 43 genetic profiles with sporadic mutations in regulatory genes and acquired mutations in 2 structural genes. Except for two regulatory gene mutants, all strains tested had the same biofilm formation capacity and displayed similar adherence and invasion of pulmonary epithelial cells and phagocytosis and survival in human macrophages. This large outbreak of GAS infection in a post-surgery oncology unit, a setting that contains highly susceptible patients, arose from a strain of the emergent emm89 clade. No relationship between punctual or acquired mutations, invasive status, and strain phenotypic characteristics was found. Noteworthy, the phenotypic characteristics of this clone account for its emergence and its remarkable capacity to elicit outbreaks.

Group B Streptococcus (GBS) is the leading cause of neonatal infections in industrialized countries. Intrapartum antibiotic prophylaxis (IAP) given to colonized parturients is a key step for the prevention of neonatal early-onset infection. We compared the performances of Xpert® GBS polymerase chain reaction (PCR) (Cepheid, Sunnyvale, CA, USA) as a point-of-care system in labor wards to standard culture for intrapartum GBS detection. Pregnant women with a GBS-positive antenatal screening were prospectively included. A vaginal double swab was collected at the time of delivery for point-of-care Xpert® GBS PCR and GBS culture. A total of 565 pregnant women were included. Valid Xpert® GBS results were obtained for 488 (86.4%) women on the first attempt. Repeat testing improved the PCR success to 516 (91.3%) women. Among the 305 women positive for GBS by culture at delivery, only 238 (78.0%) were positive by Xpert® GBS PCR, cycle thresholds being correlated to culture quantification. Among 260 women negative for GBS culture, 56 (21.5%) were positive by Xpert® GBS PCR, including 50 where IAP was initiated before vaginal sampling. Overall, among the 565 women with GBS antenatal positive culture, only 335 (59.3%) were still positive at delivery whatever the technique used, resulting in unnecessary IAP for 40% of them. This large cohort study comparing intrapartum to antepartum GBS detection provides evidence that (i) Xpert® GBS PCR might be a valuable solution for intrapartum GBS detection compared to culture-based strategies and (ii) laboratory training of non-specialized staff is mandatory to reach the performances required for point-of-care tests.

Group A Streptococcus (GAS), a Gram-positive human-specific pathogen yields 517,000 deaths annually worldwide, including 163,000 due to invasive infections and among them puerperal fever. GAS is their most feared etiologic agent. Puerperal fever still accounts for more than 75,000 maternal deaths annually and before the introduction of efficient prophylactic measures 10% childbirths were followed by the mother’s death. Yet little is known regarding GAS invasive infection establishment or GAS efficiency in causing postpartum infection. To characterize its early steps, we set up coordinated analyses of ex vivo infection of the human decidua, the puerperal fever portal of entry. We analyzed GAS behavior and the immune response triggered. We demonstrate that GAS (i) benefits from tissue secreted products to multiply; (ii) invades the tissue and leads to the death of half the cells within two hours via SpeB protease and Streptolysin O activities, respectively; (iii) impairs the tissue immune response. Immune impairment occurs both at the RNA level, with the induction of only a restricted immediate innate immune response, and at the protein level, in a SLO- and SpeB-dependent manner. Our study indicates that GAS efficient decidua invasion and immune response restraint favor its propensity to develop rapid invasive infections in a gynecological-obstetrical context.

BACKGROUND In infants, the mode of acquisition of CC17 group B Streptococcus (GBS), the hypervirulent clone responsible for late-onset disease (LOD), remains elusive. METHODS In a prospective multicenter study in France, we evaluated GBS colonization in mother-baby pairs with 2 months of follow-up between 2012 and 2015. Criteria included positivity for GBS colonization at antenatal screening or at delivery. Maternal vaginal samples and infant oral cavity and stool samples were analyzed at delivery, 21 ± 7 days (D21), and 60 ± 7 days (D60) post-delivery. RESULTS A total of 890 mother-baby pairs were analyzed. GBS colonized 7%, 21%, and 23% of the infants at birth, D21, and D60, respectively, of which 10%, 11%, and 13% were identified as CC17 GBS. Concordance between maternal and infant GBS type was 96%. At D21, the main risk factors for infant colonization by GBS were simultaneous maternal colonization of the vagina (odds ratio [OR], 4.50; 95% confidence interval [CI], 1.69-15.61) and breast milk (OR, 7.93; 95% CI, 3.81-17.14). Importantly, 38% (95% CI, 23%-56%) of infants colonized by CC17 GBS appeared colonized for the first time at D60 vs 18% (95% CI, 14%-24%; P < .049) of infants colonized by non-CC17 GBS. Multivariate analysis showed a higher risk for de novo infant colonization by CC17 at D60 than by other GBS (OR, 2.45; 95% CI, 1.02-5.88). CONCLUSIONS The high incidence of CC17 GBS in LOD is likely due to an enhanced post-delivery mother-to-infant transmission.

Group A Streptococcus (GAS) is a human-specific pathogen responsible for a wide range of diseases, ranging from superficial to life-threatening invasive infections, including endometritis, and autoimmune sequelae. GAS strains express a vast repertoire of virulence factors that varies depending on the strain genotype, and many adhesin proteins that enable GAS to adhere to host cells are restricted to some genotypes. GAS emm28 is the third most prevalent genotype in invasive infections in France and is associated with gyneco-obstetrical infections. emm28 strains harbor R28, a cell wall–anchored surface protein that has previously been reported to promote adhesion to cervical epithelial cells. Here, using cellular and biochemical approaches, we sought to determine whether R28 supports adhesion also to other cells and to characterize its cognate receptor. We show that through its N-terminal domain, R28(Nt), R28 promotes bacterial adhesion to both endometrial–epithelial and endometrial–stromal cells. R28(Nt) was further subdivided into two domains, and we found that both are involved in cell binding. R28(Nt) and both subdomains interacted directly with the laminin-binding α3β1, α6β1, and α6β4 integrins; interestingly, these bindings events did not require divalent cations. R28 is the first GAS adhesin reported to bind directly to integrins that are expressed in most epithelial cells. Finally, R28(Nt) also promoted binding to keratinocytes and pulmonary epithelial cells, suggesting that it may be involved in supporting the prevalence in invasive infections of the emm28 genotype.

Gram-positive Streptococcus pyogenes (group A Streptococcus or GAS) is a major skin pathogen and interacts with keratinocytes in cutaneous tissues. GAS can cause diverse suppurative and inflammatory infections, such as cellulitis, a common acute bacterial dermo-hypodermitis with a high morbidity. Bacterial isolation yields from the lesions are low despite the strong local inflammation observed, raising numerous questions about the pathogenesis of the infection. Using an in vitro model of GAS-infected keratinocytes, we show that the major ROS produced is the superoxide anion ([Formula: see text]), and that its production is time- and dose-dependent. Using specific modulators of ROS production, we show that [Formula: see text] is mainly synthesized by the cytoplasmic NADPH oxidase. Superoxide anion production leads to keratinocyte necrosis but incomplete inhibition of GAS growth, suggesting that GAS may be partially resistant to the oxidative burst. In conclusion, GAS-stimulated keratinocytes are able to develop an innate immune response based on the production of ROS. This local immune response limits GAS development and induces keratinocyte cell death, resulting in the skin lesions observed in patients with cellulitis.

Context Emm1-type group A Streptococcus (GAS), or Streptococcus pyogenes, is mostly responsible for invasive infections such as necrotizing fasciitis (NF) and streptococcal toxic shock syndrome (STSS). The recommended treatment of severe invasive GAS infections is a combination of clindamycin and penicillin. Until 2012, almost all emm1 isolates were susceptible to clindamycin. Objectives We aimed to identify the phenotypic and genotypic characteristics of emm1 GAS clone resistant to clindamycin. Methods GAS strains were characterized by emm sequence typing, detection of genes encoding pyrogenic exotoxins or superantigens. Cluster analysis was performed by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Antibiotic susceptibility was assessed using disk diffusion and resistance genes were detected by PCR. Results A total of 1321 GAS invasive isolates were analyzed between January 2011 and December 2012. The overall number of invasive isolates resistant to clindamycin was 52 (3.9%); seven of them were emm1 isolates. All isolates had the same genomic markers: macrolide resistance due to the presence of the erm(B) gene, emm subtype 1.0, the same toxin or superantigen profile, PFGE pattern and sequence type. Conclusion This is the first description of highly virulent GAS emm1 isolates resistant to clindamycin in France. This article strengthens the need for monitoring the epidemiology of invasive GAS strains as they could lead to changes in treatment guidelines.

Streptococcus pyogenes (group A Streptococcus [GAS]) is the leading cause of bacterial pharyngitis. To perform a rapid diagnosis of GAS pharyngitis, rapid antigen detection tests (RADTs) have been developed. In this study, we evaluated and compared the sensitivity and specificity of 5 RADTs (bioNexia Strep A plus™, bioNexia Strep A dipstick™, Clearview Strep A™, QuickVue Strep A plus™, and Streptatest™), using analytical approaches combining dilutions in NaCl 0.9% or in pharyngeal flora. The practicability of each RADT was also determined. Among the 630 RADTs performed in this work, all were specific, as no false positive was found resulting in a specificity of 100%. The 5 RADTs detected GAS at 10 6 CFU/mL in NaCl 0.9% or pooled pharyngeal flora. Regarding the practicability analysis, bioNexia Strep A plus, bioNexia Strep A dipstick and Streptatest RADTs obtained the highest scores for secondary items including kit content and instructions for use information. We concluded that these 5 easy-to-use RADTs are suitable for diagnosis of GAS pharyngitis, as they all detect GAS at a concentration commonly found during pharyngitis.

Sixty-three cases of Streptococcus pyogenes meningitis in adults were studied. Three predominant emm types were associated with meningitis: emm1 (44%), emm3 (11%), and emm6 (11%). Streptococcal toxic shock syndrome and mortality rates were 40% and 38%, respectively.

This study describes the clinical and microbiological features associated with group B Streptococcus (GBS) bone and joint infections (BJIs). It was a retrospective analysis of adult cases of GBS BJIs reported to the French National Reference Center for Streptococci from January 2004 to December 2014. Clinical data and GBS molecular characteristics are reported. Strains were collected from 163 patients. The most frequent comorbidities were: solid organ cancer (n = 21, 21%) and diabetes mellitus (n = 20, 20%). The main infection sites were knee (47/155 = 30%) and hip (43/155 = 27%), and occurred on orthopedic devices in 71/148 cases (48%). CPS III (n = 47, 29%), Ia (n = 26, 16%) and V (n = 40, 25%) were predominant. Resistance to erythromycin, clindamycin and tetracycline was detected in 55/163 (34%), 35/163 (21%) and 132/163 (81%) strains, respectively. The most frequent sequence types were ST-1 (n = 21, 25%), ST-17 (n = 17, 20%) and ST-23 (n = 11, 13%). The rate of resistance to erythromycin was 0% for ST-17 strains, 52% (n = 11) for ST-1 and 44% (n = 7) for ST-23 (p 0.001). GBS bone and joint infections predominantly occur in patients aged50 years and/or with comorbidities such as cancer and diabetes mellitus. CPS type distribution and MLST are very similar to that of other adult GBS invasive infections.

Resume Le streptocoque du groupe A (SGA) est un germe humain responsable d’un large eventail de manifestations cliniques. Les infections invasives a SGA sont en recrudescence depuis le milieu des annees 1980. Afin d’etudier l’epidemiologie des infections invasives a SGA en France, nous avons caracterise toutes les souches invasives recues au Centre national de reference des streptocoques (CNR-Strep) entre 2007 et 2011 et analyse les questionnaires de renseignements cliniques accompagnant les souches. Pour chaque souche ont ete determines le genotype emm , les genes de superantigenes et la sensibilite aux antibiotiques. Sur les 2 603 souches invasives non redondantes de SGA etudiees, 65,1 % ( n = 1 695) provenaient d’hemoculture. Un syndrome de choc toxique streptococcique (SCTS) etait decrit dans 16,4 % ( n = 428) des cas, notamment en cas de dermohypodermite necrosante (DHN), d’infections pleuropulmonaires ou osteo-articulaires ( p ≤ 0,001). Le taux de mortalite s’elevait a 10,6 %. Au total, 102 genotypes emm differents ont ete identifies. Trois genotypes predominaient, atteignant pres de 60 % des souches : emm 1 (26,7 %), emm 28 (16,4 %), et emm 89 (12,8 %). La preponderance de chaque genotype emm etait variable selon les annees et l’âge des patients. Chez les emm 1 (36,8 %), emm 12 (12,9 %) et emm 4 (9,5 %). La distribution des genes de superantigenes ( Spe A, Spe C et Ssa ) etait restreinte a certains genotypes emm . Entre 2007 et 2011, le taux de resistance aux macrolides des SGA a diminue de 7,8 a 5,5 %. Les souches emm 1 restent les plus repandues, en particulier lors des manifestations cliniques les plus severes (SCTS, DHN).

Background Streptococcus suis is a zoonotic pathogen which represents the leading cause of meningitis in Southeast Asia and an emerging pathogen in the Western world, the main risk factor for infection being contact with pigs. In Africa, the prevalence of S. suis infections in swine and humans is largely unrecognized, with only one recent report of a limited case series. Case presentation We describe a human case of meningitis due to S. suis in a 32-year-old man living in Togo. The patient had no particular medical history and no risk factors for immunodeficiency but reported regular contact with pork products. Using specific immunological and molecular methods, we characterized the isolate as S. suis serotype 2, ST1, one the most prevalent and virulent clone worldwide. The outcome was favorable after one week of adapted antibiotic therapy but the patient was left with severe hearing disorders. Conclusions This work highlights the emergence of this pathogen in Africa and reinforces the need for accurate epidemiological and surveillance studies of S. suis infections and for educating clinicians and exposed groups in non-endemic countries.

M/emm typing, based either on serotyping of the M protein or on sequencing of the emm gene, is a major tool for epidemiological studies of group A streptococci (GAS). In order to simplify M/emm typing, we designed two multiplex polymerase chain reaction (PCR) formats capable of identifying the most frequent GAS M/emm types involved in invasive infections and antimicrobial resistance. A heptaplex PCR procedure was first developed in a conventional format coupled with gel electrophoresis to identify emm types 1, 3, 4, 6, 12, 28, and 89, based on the size of the amplification products. The other method, designed to identify the same seven emm types, together with emm11, was based on a real-time PCR format coupled with high-resolution melting (HRM) analysis, allowing the rapid typing of large strain collections.

Since the 1980s, infections due to Streptococcus pyogenes or group A streptococci (GAS) were marked by the increase in invasive infections and the emergence of clones which were resistant to macrolides. Those challenges led the French national reference center for streptococci to enhance the epidemiological survey and the characterization of GAS strains, in collaboration with the National Institute for Public Health Surveillance. Active surveillance is of major importance for implementation of therapeutic and prophylactic guidelines and for evaluation of future streptococcal vaccines.

A new Escherichia coli virulent clonal group, O45:K1, belonging to the highly virulent subgroup B2 1 was recently identified in France, where it accounts for one-third of E. coli neonatal meningitis cases. Here we describe the sequence, epidemiology and function of the large plasmid harbored by strain S88, which is representative of the O45:K1 clonal group. Plasmid pS88 is 133,853 bp long and contains 144 protein-coding genes. It harbors three different iron uptake systems (aerobactin, salmochelin, and the sitABCD genes) and other putative virulence genes ( iss , etsABC , ompT P , and hlyF ). The pS88 sequence is composed of several gene blocks homologous to avian pathogenic E. coli plasmids pAPEC-O2-ColV and pAPEC-O1-ColBM. PCR amplification of 11 open reading frames scattered throughout the plasmid was used to investigate the distribution of pS88 and showed that a pS88-like plasmid is present in other meningitis clonal groups such as O18:K1, O1:K1, and O83:K1. A pS88-like plasmid was also found in avian pathogenic strains and human urosepsis strains belonging to subgroup B2 1 . A variant of S88 cured of its plasmid displayed a marked loss of virulence relative to the wild-type strain in a neonatal rat model, with bacteremia more than 2 log CFU/ml lower. The salmochelin siderophore, a known meningovirulence factor, could not alone explain the plasmid's contribution to virulence, as a salmochelin mutant displayed only a minor fall in bacteremia (0.9 log CFU/ml). Thus, pS88 is a major virulence determinant related to avian pathogenic plasmids that has spread not only through meningitis clonal groups but also human urosepsis and avian pathogenic strains.

We report the sequence of the Streptococcus pyogenes emm28 strain M28PF1, isolated from a patient with postpartum endometritis. The M28 protein is smaller than that of MGAS6180 (NC_007296.1). Furthermore, the 1,896,976-bp-long chromosome presents, compared to that of MGAS6180, an inversion between the two comX genes.

Streptococcus pyogenes (group A Streptococcus [GAS]) causes a wide variety of diseases, ranging from mild noninvasive to severe invasive infections. Mutations in regulatory components have been implicated in the switch from colonization to invasive phenotypes. The inactivation of the sil locus, composed of six genes encoding a quorum-sensing complex, gives rise to a highly invasive strain. However, studies conducted on limited collections of GAS strains suggested that sil prevalence is around 15%; furthermore, whereas a correlation between the presence of sil and the genetic background was suggested, no link between the presence of a functional sil locus and the invasive status was assessed. We established a collection of 637 nonredundant strains covering all emm genotypes present in France and of known clinical history; 68%, 22%, and 10% were from invasive infections, noninvasive infections, and asymptomatic carriage, respectively. Among the 637 strains, 206 were sil positive. The prevalence of the sil locus varied according to the emm genotype, being present in >85% of the emm4 , emm18 , emm32 , emm60 , emm87 , and emm90 strains and absent from all emm1 , emm28 , and emm89 strains. A random selection based on 2009 French epidemiological data indicated that 16% of GAS strains are sil positive. Moreover, due to mutations leading to truncated proteins, only 9% of GAS strains harbor a predicted functional sil system. No correlation was observed between the presence or absence of a functional sil locus and the strain invasiveness status.

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%).

International audience; BACKGROUND: Observational studies showed that the profile of infective endocarditis (IE) significantly changed over the past decades. However, most studies involved referral centers. We conducted a population-based study to control for this referral bias. The objective was to update the description of characteristics of IE in France and to compare the profile of community-acquired versus healthcare-associated IE. METHODS: A prospective population-based observational study conducted in all medical facilities from 7 French regions (32% of French individuals aged ≥18 years) identified 497 adults with Duke-Li-definite IE who were first admitted to the hospital in 2008. Main measures included age-standardized and sex-standardized incidence of IE and multivariate Cox regression analysis for risk factors of in-hospital death. RESULTS: The age-standardized and sex-standardized annual incidence of IE was 33.8 (95% confidence interval [CI], 30.8-36.9) cases per million inhabitants. The incidence was highest in men aged 75-79 years. A majority of patients had no previously known heart disease. Staphylococci were the most common causal agents, accounting for 36.2% of cases (Staphylococcus aureus, 26.6%; coagulase-negative staphylococci, 9.7%). Healthcare-associated IE represented 26.7% of all cases and exhibited a clinical pattern significantly different from that of community-acquired IE. S. aureus as the causal agent of IE was the most important factor associated with in-hospital death in community-acquired IE (hazard ratio [HR], 2.82 [95% CI, 1.72-4.61]) and the single factor in healthcare-associated IE (HR, 2.54 [95% CI, 1.33-4.85]). CONCLUSIONS: S. aureus became both the leading cause and the most important prognostic factor of IE, and healthcare-associated IE appeared as a major subgroup of the disease.

Toxic shock syndrome (TSS) and septic shock (SS) share many clinical signs of an exacerbated inflammatory response. In this report, we investigated whether TSS presents similar features of delayed immunosuppression as described in SS. Five children with TSS from paediatric intensive care units in a university hospital were monitored. TSS cases were defined by the association of standardized clinical signs of TSS and confirmed by measurement of specific Vbeta expansions corresponding to toxin gene profile of the isolated strains. As in SS, an increased percentage of circulating regulatory T cells (Treg) was observed in patients with TSS. However, in contrast to SS, neither lymphopenia nor decreased HLA-DR expression on monocytes was measured. In conclusion, whereas SS and TSS exhibited similar clinical presentation, the present observation suggests that respective pathophysiological mechanisms induce different immune alterations. Future studies must isolate and better characterize the phenotypic and functional properties of Treg subsets during TSS to understand the mechanisms sustaining their increase, especially the putative role of superantigens.

Group A Streptococcus (GAS) infections present high morbidity and mortality rates and consequently remain a significant health problem. The emm3 isolates induce more severe pathologies than all others. In this study, we tested, on a collection of invasive and non-invasive emm3 clinical isolates, whether in that genotype the invasive status of the strains affects the innate immune response. We show that phagocytosis is dependent on the invasiveness of the isolates. Interestingly, all emm3 isolates compromise macrophage integrity, already noticeable 1 h after infection. Inflammatory modulators (IL-6, TNF-α and IFN-β) are nevertheless detected during at least 6 h post-infection. This is a likely consequence of the macrophages not being all infected. The efficient and rapid induction of macrophage death could explain the virulence of the emm3 strains.

To the Editor: Streptococcus pyogenes, or group A streptococci (GAS), are human pathogens responsible for pharyngitis as well as skin and soft tissue infections. Invasive GAS diseases, including bacteremia, cellulitis, and necrotizing fasciitis, are life-threatening, especially when associated with toxic shock syndrome. Several risk factors for GAS infections are known, such as diabetes, immunosuppression, drug use, and skin lesions (1,2).

A new highly pathogenic clone of Escherichia coli meningitis strains harboring the unusual serogroup O45 has recently emerged in France. To gain insight into the pathogenicity of this new clone, we investigated the possible role of antigen O45 in the virulence of strain S88 (O45:K1:H7), representative of this emerging clone. We first showed that the S88 O-antigen gene cluster sequence differs from that of O45 in the reference strain E. coli 96-3285, suggesting that the two O45 polysaccharides, while probably sharing a community of epitopes, represent two different antigens. The unique functional organization of the two O-antigen gene clusters and the low DNA sequence homology of the orthologous genes suggest that the two loci originated from a common ancestor and have since undergone multiple recombination events. Phylogenetic analysis based on the flanking gene gnd sequences indicates that the S88 antigen O45 (O45 S88 ) gene cluster may have been acquired, at least in part, from another member of the Enterobacteriaceae . Mutagenesis of the O45 S88 antigen gene cluster was used for functional analysis of the loci and revealed the crucial role of the O polysaccharide in S88 virulence in a neonatal rat meningitis model. We also developed a PCR method to specifically identify the O45 S88 antigen gene cluster. Together, our findings suggest that horizontal acquisition of a new O-antigen gene cluster, at least partly from another species, may have been a key event in the emergence and virulence of the E. coli O45:K1:H7 clone in France.

International audience; Group A Streptococcus (GAS) infections remain a significant health care problem due to high morbidity and mortality associated with GAS diseases, along with their increasing worldwide prevalence. Macrophages play a key role in the control and clearance of GAS infections. Moreover, pro-inflammatory cytokines production and GAS persistence and invasion are related. In this study we investigated the correlation between the GAS clinical isolates genotypes, their known clinical history, and their ability to modulate innate immune response. We constituted a collection of 40 independent GAS isolates representative of the emm types currently prevalent in France and responsible for invasive (57.5%) and non-invasive (42.5%) clinical manifestations. We tested phagocytosis and survival in mouse bone marrow-derived macrophages and quantified the pro-inflammatory mediators (IL-6, TNF-α) and type I interferon (INF-β) production. Invasive emm89 isolates were more phagocytosed than their non-invasive counterparts, and emm89 isolates more than the other isolates. Regarding the survival, differences were observed depending on the isolate emm type, but not between invasive and non-invasive isolates within the same emm type. The level of inflammatory mediators produced was also emm type-dependent and mostly invasiveness status independent. Isolates of the emm1 type were able to induce the highest levels of both pro-inflammatory cytokines, whereas emm89 isolates induced the earliest production of IFN-β. Finally, even within emm types, there was a variability of the innate immune responses induced, but survival and inflammatory mediator production were not linked.

Importance Infective endocarditis (IE) is a rare disease with poor prognosis. When IE is suspected, skin examination is mandatory to look for a portal of entry and classic skin lesions to help diagnose and manage the condition. Objectives To describe the prevalence of and factors associated with dermatological manifestations in patients with definite IE. Design Observational, prospective, population-based epidemiological study between January 1 and December 31, 2008. Subsequently, collected dermatological data were subjected to post hoc analysis. Setting and Participants Patients (n = 497) diagnosed in 7 French regions and hospitalized in France for definite IE satisfying modified Duke criteria. Main Outcomes and Measures Patient and disease epidemiological information was collected, focusing on the most classic dermatological manifestations of IE (Osler nodes, Janeway lesions, purpura, and conjunctival hemorrhages). Disease outcome was also recorded. Results Among 497 definite IE cases, 487 had known dermatological status. Of 487 cases, 58 (11.9%) had skin manifestations, including 39 (8.0%) with purpura, 13 (2.7%) with Osler nodes, 8 (1.6%) with Janeway lesions, and 3 (0.6%) with conjunctival hemorrhages (5 patients had 2 skin manifestations). Patients with skin manifestations had a higher rate of IE-related extracardiac complications than patients without skin manifestations, particularly cerebral emboli (32.8% vs 18.4%, P = .01), without increased mortality. Patients with purpura had larger cardiac vegetations (18.1 vs 13.7 mm, P = .01), and Janeway lesions were associated with more extracerebral emboli (75.0% vs 31.8%, P = .02). Conclusions and Relevance Specific skin manifestations of IE are associated with a higher risk of complications and should alert physicians to examine for extracardiac complications, notably with cerebral imaging.