Hospital-acquired invasive group a streptococcal infections in Ontario, Canada, 1992-2000

Outcomes and management of pregnancy and puerperal group A streptococcal infections: A systematic review

INTRODUCTION

Group A streptococcus (Streptococcus pyogenes) is one of the most lethal bacterial pathogens of humans, with increased risk of progression to septic shock and multiorgan failure in the pregnant population. The objective of this study is to systematically review the outcomes and management strategies for pregnancy and puerperal group A streptococcus infections in an effort to provide further guidance for prevention and treatment of a rare but lethal infection worldwide.

MATERIAL AND METHODS

A comprehensive search using puerperium and streptococcus pyogenes terms was completed across several registered databases. A total of 902 articles investigating pregnancy and puerperal group A streptococcus infection were identified, with 40 studies fulfilling inclusion criteria of original research articles in humans published from 1990 onwards reporting four or more unique cases of group A streptococcus in pregnancy or postpartum. This study was registered in PROSPERO: CRD42020198983.

RESULTS

A total of 1160 patients with pregnancy and puerperal group A streptococcus infection were identified. Most infections occurred postpartum (91.9%), with 4.7% reported antepartum and 0.6% intrapartum. Bacteremia was present in 49.0% of patients and endometritis in 45.9%. Puerperal sepsis was described in 28.2% of cases and progressed to streptococcal toxic shock syndrome in one-third of such cases. Overall, the case fatality ratio was 2.0%, with one-third of the deaths from antenatal cases including 3/22 (13.6%) cases of septic abortion and 10/46 (21.7%) antenatal cases of group A streptococcus infection.

CONCLUSIONS

Group A streptococcus infection remains an important contributor to pregnancy and puerperal morbidity and mortality. Early recognition, diagnosis and aggressive management are important for favorable outcomes given the serious risk of sepsis and streptococcal toxic shock syndrome.

Invasive group A streptococcal disease in pregnant women and young children: a systematic review and meta-analysis

BACKGROUND

The incidence of invasive disease caused by group A streptococcus (GAS) has increased in multiple countries in the past 15 years. However, despite these reports, to the best of our knowledge, no systematic reviews and combined estimates of the incidence of invasive GAS have been done in key high-risk groups. To address this, we estimated the incidence of invasive GAS disease, including death and disability outcomes, among two high-risk groups-namely, pregnant women and children younger than 5 years.

METHODS

We did a systematic review and meta-analyses on invasive GAS outcomes, including incidence, case fatality risks, and neurodevelopmental impairment risk, among pregnant women, neonates (younger than 28 days), infants (younger than 1 year), and children (younger than 5 years) worldwide and by income region. We searched several databases for articles published from Jan 1, 2000, to June 3, 2020, for publications that reported invasive GAS outcomes, and we sought unpublished data from an investigator group of collaborators. We included studies with data on invasive GAS cases, defined as laboratory isolation of Streptococcus pyogenes from any normally sterile site, or isolation of S pyogenes from a non-sterile site in a patient with necrotising fasciitis or streptococcal toxic shock syndrome. For inclusion in pooled incidence estimates, studies had to report a population denominator, and for inclusion in pooled estimates of case fatality risk, studies had to report aggregate data on the outcome of interest and the total number of cases included as a denominator. We excluded studies focusing on groups at very high risk (eg, only preterm infants). We assessed heterogeneity with I2.

FINDINGS

Of the 950 published articles and 29 unpublished datasets identified, 20 studies (seven unpublished; 3829 cases of invasive GAS) from 12 countries provided sufficient data to be included in pooled estimates of outcomes. We did not identify studies reporting invasive GAS incidence among pregnant women in low-income and middle-income countries (LMICs) nor any reporting neurodevelopmental impairment after invasive GAS in LMICs. In nine studies from high-income countries (HICs) that reported invasive GAS in pregnancy and the post-partum period, invasive GAS incidence was 0·12 per 1000 livebirths (95% CI 0·11 to 0·14; I2=100%). Invasive GAS incidence was 0·04 per 1000 livebirths (0·03 to 0·05; I2=100%; 11 studies) for neonates, 0·13 per 1000 livebirths (0·10 to 0·16; I2=100%; ten studies) for infants, and 0·09 per 1000 person-years (95% CI 0·07 to 0·10; I2=100%; nine studies) for children worldwide; 0·12 per 1000 livebirths (95% CI 0·00 to 0·24; I2=100%; three studies) in neonates, 0·33 per 1000 livebirths (-0·22 to 0·88; I2=100%; two studies) in infants, and 0·22 per 1000 person-years (0·13 to 0·31; I2=100%; two studies) in children in LMICs; and 0·02 per 1000 livebirths (0·00 to 0·03; I2=100%; eight studies) in neonates, 0·08 per 1000 livebirths (0·05 to 0·11; I2=100%; eight studies) in infants, and 0·05 per 1000 person-years (0·03 to 0·06; I2=100%; seven studies) in children for HICs. Case fatality risks were high, particularly among neonates in LMICs (61% [95% CI 33 to 89]; I2=54%; two studies).

INTERPRETATION

We found a substantial burden of invasive GAS among young children. In LMICs, little data were available for neonates and children and no data were available for pregnant women. Incidences of invasive GAS are likely to be underestimates, particularly in LMICs, due to low GAS surveillance. It is essential to improve available data to inform development of prevention and management strategies for invasive GAS.

FUNDING

Wellcome Trust.

Nosocomial outbreaks: A review of governmental reporting systems

OBJECTIVE

Identifying and describing components of existent governmental reporting systems of NO aiming at informing the design of the implementation of NO reporting systems in countries where they were not fully established.

DESIGN

A systematic search was carried out on PubMed, Embase, and the Latin American and Caribbean Health Sciences Literature database. We included studies published from January 2007 to June 2019 describing NO governmental reporting systems. Additionally, we included studies from the list of references in the identified papers, to gather more information about NO reporting systems. We also reviewed documents published in the governmental health department's Web sites, such as outbreak management guidelines and surveillance protocols, provided they were cited in the papers.

RESULTS

NO reporting systems were reported in France (Alsace Region), Germany, Norway, United Kingdom, United States (New York State; New York City), Australia (Victoria State), Sweden (Skane Region), Ireland, Scotland (Lothian Region), and Canada (Winnipeg; Ontario). These systems vary according to the type of targeted NO event, such as gastroenteritis, influenza-like illness, invasive group A streptococcal disease or all-health care-acquired infection NO. Germany, Norway, New York City, New York State, Ireland, Winnipeg, and Ontario have established a mandatory reporting for NO.

CONCLUSIONS

There is high variability among countries regarding governmental NO reporting systems. This may hinder opportune inter- and intracountries communication concerning NO of potential international public health relevance.

Compartmentalized Polymeric Nanoparticles Deliver Vancomycin in a pH-Responsive Manner

Vancomycin (VCM) is a last resort antibiotic in the treatment of severe Gram-positive infections. However, its administration is limited by several drawbacks such as: strong pH-dependent charge, tendency to aggregate, low bioavailability, and poor cellular uptake. These drawbacks were circumvented by engineering pH-responsive nanoparticles (NPs) capable to incorporate high VCM payload and deliver it specifically at slightly acidic pH corresponding to infection sites. Taking advantage of peculiar physicochemical properties of VCM, here we show how to incorporate VCM efficiently in biodegradable NPs made of poly(lactic-co-glycolic acid) and polylactic acid (co)polymers. The NPs were prepared by a simple and reproducible method, establishing strong electrostatic interactions between VCM and the (co)polymers’ end groups. VCM payloads reached up to 25 wt%. The drug loading mechanism was investigated by solid state nuclear magnetic resonance spectroscopy. The engineered NPs were characterized by a set of advanced physicochemical methods, which allowed examining their morphology, internal structures, and chemical composition on an individual NP basis. The compartmentalized structure of NPs was evidenced by cryogenic transmission electronic microscopy, whereas the chemical composition of the NPs’ top layers and core was obtained by electron microscopies associated with energy-dispersive X-ray spectroscopy. Noteworthy, atomic force microscopy coupled to infrared spectroscopy allowed mapping the drug location and gave semiquantitative information about the loadings of individual NPs. In addition, the NPs were stable upon storage and did not release the incorporated drug at neutral pH. Interestingly, a slight acidification of the medium induced a rapid VCM release. The compartmentalized NPs could find potential applications for controlled VCM release at an infected site with local acidic pH.

Outbreaks in Health Care Settings

Outbreaks and pseudo-outbreaks in health care settings are complex and should be evaluated systematically using epidemiologic and molecular tools. Outbreaks result from failures of infection prevention practices, inadequate staffing, and undertrained or overcommitted health care personnel. Contaminated hands, equipment, supplies, water, ventilation systems, and environment may also contribute. Neonatal intensive care, endoscopy, oncology, and transplant units are areas at particular risk. Procedures, such as bronchoscopy and endoscopy, are sources of infection when cleaning and disinfection processes are inadequate. New types of equipment can be introduced and lead to contamination or equipment and medications can be contaminated at the manufacturing source.

The Place of Group A Streptococci in Moroccan Children with Pharyngitis and Emm Type Distribution

Background: Streptococcus pyogenes is responsible for a wide variety of diseases, including noninvasive and severe invasive infections. The emm gene encodes the M protein that is the virulence factor and immunological determinant of group A streptococci. Emm typing is the group A Streptococci (GAS) standard molecular typing method based on the amplification of the N terminal hypervariable region of the emm gene. Objectives: The aim of the present study was to determine the prevalence of GAS in children with pharyngitis and determine different types of emm gene in the GAS isolates using emm typing. Methods: The study was carried out over a period of 14 months (from February 2017 to March 2018). Throat samples were collected from cases aged ≤ 18 years with pharyngitis referring to a primary health care center in Fez, Morocco. GAS isolates were subjected to conventional tests to confirm species identification. Antimicrobial susceptibility testing was performed using the standard disk diffusion method. We researched emm gene by a polymerase chain reaction (PCR). Emm types were determined by a sequence-based protocol. Demographic and clinical data were recorded from each patient. Results: From a total of 177 throat samples, 11 isolates (6.2%) were identified as GAS in children with pharyngitis. Antibiotic sensitivity testing revealed that all the GAS isolates were sensitive to penicillin. The sequencing of the PCR products of the emm gene revealed that emm90 was the most obtained emm type (30,77%); while emm75 was the least type observed (7.7%). Conclusions: The emm90 is the most prevalent type detected from patients with tonsillitis. Penicillin and erythromycin are still the foremost effective antibiotics to treat GAS pharyngitis.

Modes of transmission and attack rates of group A Streptococcal infection: a protocol for a systematic review and meta-analysis

BACKGROUND

Group A Streptococcus (Strep A) is an important cause of mortality and morbidity globally. This bacterium is responsible for a range of different infections and post-infectious sequelae. Summarising the current knowledge of Strep A transmission to humans will address gaps in the evidence and inform prevention and control strategies. The objective of this study is to evaluate the modes of transmission and attack rates of group A streptococcal infection in human populations.

METHODS

This systematic review protocol was prepared according to the Preferred Reporting Items for Systematic reviews and Meta-analysis Protocols (PRISMA-P) 2015 Statement. Using a comprehensive search strategy to identify any transmission studies that have been published in English since 1980, full-text articles will be identified and considered for inclusion against predefined criteria. We will include all studies reporting on Strep A transmission, who have identified a mode of transmission, and who reported attack rates. Risk of bias will be appraised using an appropriate tool. Our results will be described narratively and where feasible and appropriate, a meta-analysis utilizing the random-effects model will be used to aggregate the incidence proportions (attack rates) for each mode of transmission. In addition, we will also evaluate the emm genotype variants of the M protein causing Strep A infection and the association with transmission routes and attack rates, if any, by setting, socioeconomic background and geographical regions.

DISCUSSION

We anticipate that this review will contribute to elucidating Strep A modes of transmission which in turn, will serve to inform evidence-based strategies including environmental health activities to reduce the transmission of Strep A in populations at risk of severe disease.

TRIAL REGISTRATION

Systematic review registration: PROSPERO ( CRD42019138472 ).

An Outbreak of Streptococcus pyogenes in a Mental Health Facility: Advantage of Well-Timed Whole-Genome Sequencing Over emm Typing

OBJECTIVEWe report the utility of whole-genome sequencing (WGS) conducted in a clinically relevant time frame (ie, sufficient for guiding management decision), in managing a Streptococcus pyogenes outbreak, and present a comparison of its performance with emm typing.SETTINGA 2,000-bed tertiary-care psychiatric hospital.METHODSActive surveillance was conducted to identify new cases of S. pyogenes. WGS guided targeted epidemiological investigations, and infection control measures were implemented. Single-nucleotide polymorphism (SNP)-based genome phylogeny, emm typing, and multilocus sequence typing (MLST) were performed. We compared the ability of WGS and emm typing to correctly identify person-to-person transmission and to guide the management of the outbreak.RESULTSThe study included 204 patients and 152 staff. We identified 35 patients and 2 staff members with S. pyogenes. WGS revealed polyclonal S. pyogenes infections with 3 genetically distinct phylogenetic clusters (C1-C3). Cluster C1 isolates were all emm type 4, sequence type 915 and had pairwise SNP differences of 0-5, which suggested recent person-to-person transmissions. Epidemiological investigation revealed that cluster C1 was mediated by dermal colonization and transmission of S. pyogenes in a male residential ward. Clusters C2 and C3 were genomically diverse, with pairwise SNP differences of 21-45 and 26-58, and emm 11 and mostly emm120, respectively. Clusters C2 and C3, which may have been considered person-to-person transmissions by emm typing, were shown by WGS to be unlikely by integrating pairwise SNP differences with epidemiology.CONCLUSIONSWGS had higher resolution than emm typing in identifying clusters with recent and ongoing person-to-person transmissions, which allowed implementation of targeted intervention to control the outbreak.Infect Control Hosp Epidemiol 2018;852-860.

An Outbreak of Severe Group A Streptococcus Infections Associated with Podiatric Application of a Biologic Dermal Substitute

OBJECTIVE

To describe an outbreak of severe Group A Streptococcus (GAS) infections that appeared to be associated with use of a biologic dermal substitute on foot wounds

DESIGN

Retrospective cohort study of cases and similar uninfected patients

SETTING/PATIENTS

Patients attending the podiatry clinic at a Veterans Affairs Medical Center between July 2011 and November 2011 INTERVENTIONS: Microbiology laboratory data were reviewed for the calendar year, a case definition was established and use of the biologic dermal substitute was discontinued. Staff were cultured to identify potentially colonized employees. A case-cohort study was designed to investigate risk factors for disease. Emm typing and pulsed field gel electrophoresis (PFGE) were performed to identify strain similarity.

RESULTS

In 10 months, 14 cases were identified, and 4 of these patients died. All strains were emm type 28 and were identical according to PFGE. Discontinuation of biologic dermal substitute use halted the outbreak. A prior stroke was more common in the case cohort vs uninfected patient cohorts. The number of patients attending the clinic on 13 probable transmission days was significantly higher than on nontransmission days. We identified 2 patients who were present in the clinic on all but 1 probable transmission day. Surveillance cultures of podiatry clinic staff and cultures of the same lot of retained graft material were negative.

CONCLUSIONS

A carrier was not identified, and we believe the outbreak was associated with inter-patient transmission likely due to lapses in infection control techniques. No additional cases have been identified in >3 years following the resumption of dermal substitute use in May 2012.

Red Flags for Necrotizing Fasciitis: A Case Control Study

OBJECTIVE

to examine the diagnostic accuracy of traditional 'red flags' for necrotizing fasciitis (NF) on history and physical examination.

METHODS

retrospective study of all cases of NF admitted to a large tertiary care hospital between January 1 2004 and December 31 2013, each matched to two control patients with cellulitis. We determined the diagnostic test characteristics of clinical features for distinguishing NF from cellulitis, with emphasis on positive (LR+) and negative (LR-) likelihood ratios.

RESULTS

There were no individual findings with sufficient sensitivity to rule out NF (sensitivity ≤ 85% and LR- ≥ 0.5 for all findings). The clinical features that most significantly increased the odds of NF were recent surgery (LR+ 7.0) pain-out-of-proportion (LR+ 4.5), diarrhea (LR+ 6.0), hypotension (LR+ 8.0), altered mental status (LR+ 3.3), erythema progressing beyond margins (LR+3.1), fluctuance (LR+ 5.0), hemorrhagic bullae (LR+ 8.0) and skin necrosis (LR+ 30.0). Each individual finding conferred low sensitivity, but absence of all nine ruled out NF (LR- 0.04). The presence of >=3 findings ruled in NF (LR+ undefined).

CONCLUSIONS

When considered together, the traditional 'red flags' for NF may be sufficient to rule in or rule out the diagnosis. If future prospective studies validate these findings, there will be a potential opportunity to expedite NF diagnosis and improve patient outcomes.

Management of invasive group A streptococcal infections

Invasive group A streptococcal (GAS) disease in children includes deep soft tissue infection, bacteraemia, bacteraemic pneumonia, meningitis and osteomyelitis. The expression of toxins and super antigens by GAS can complicate infection by triggering an overwhelming systemic inflammatory response, referred to as streptococcal toxic shock syndrome (STSS). The onset and progression of GAS disease can be rapid, and the associated mortality high. Prompt antibiotics therapy and early surgical debridement of infected tissue are essential. Adjunctive therapy with intravenous immunoglobulin and hyperbaric therapy may improve outcomes in severe disease. Nosocomial outbreaks and secondary cases in close personal contacts are not uncommon; infection control measures and consideration of prophylactic antibiotics to those at high risk are important aspects of disease control. To reduce a substantial part of the global burden of GAS disease, an affordable GAS vaccine with efficacy against a broad number of strains is needed.

An outbreak of Streptococcus pyogenes surgical site infections in a cardiovascular surgery department

BACKGROUND

We report an outbreak of surgical site infections due to genetically related strains of Streptococcus pyogenes in a cardiovascular surgery department.

METHODS

The practices that were possibly related to the outbreak were investigated through direct observation and interviews with staff by an infection control team. Surveillance sampling from patients, health-care workers, and environment were done for the investigation of the source. Pulsed-field gel electrophoresis was used to investigate a clonal relationship among the S. pyogenes isolates.

RESULTS

Four patients operated on in the cardiovascular surgery department developed surgical site infection due to S. pyogenes. Molecular characterization of S. pyogenes done by pulsed-field gel electrophoresis revealed the same strain.

CONCLUSIONS

Although a definite source for the outbreak could not be identified, probably lack of adherence to hand hygiene practices during surgical dressings, contamination, and cross contamination led to this outbreak.

Outbreak of invasive group A streptococcus infection: contaminated patient curtains and cross-infection on an ear, nose and throat ward

BACKGROUND

Outbreaks of group A streptococcus (GAS) infections may occur in healthcare settings and have been documented in surgical, obstetrics and gynaecology, and burns units. The environment may serve as a reservoir and facilitate transmission via contaminated equipment.

AIM

To describe the investigation and control of an outbreak of healthcare-associated GAS infection on an ear, nose and throat (ENT) ward in a tertiary referral centre.

METHODS

Two patients with laryngeal cancer developed invasive GAS infection (bacteraemia) with associated tracheostomy wound cellulitis within a 48 h period. The outbreak team undertook an investigation involving a retrospective review of GAS cases, prospective case finding, healthcare worker screening and sampling of patient curtains. Immediate control measures included source isolation, a thorough rolling clean with a chlorine-based disinfectant and hydrogen peroxide decontamination of patient equipment.

FINDINGS

Prospective patient screening identified one additional patient with carriage of GAS from a tracheostomy wound swab. Staff screening identified one healthcare worker who acquired GAS during the outbreak and who subsequently developed pharyngitis. Environmental sampling demonstrated that 10 out of 34 patient curtains on the ward were contaminated with GAS and all isolates were typed as emm-1.

CONCLUSION

This is the first outbreak report to demonstrate patient curtains as potential source for GAS cross-transmission, with implications in relation to hand hygiene and frequency of laundering. Based on this report we recommend that during an outbreak of GAS infection all patient curtains should be changed as part of the enhanced decontamination procedures.

Outbreak of Streptococcus pyogenes emm type 58 in a high dependency unit of a level-1 trauma center of India

Background and Aims:

Group A Streptococcus (GAS) can cause illnesses ranging from self-limited to severe, life-threatening, invasive infections. The objective of the following study was to investigate a suspected Streptococcus pyogenes outbreak in a high dependency unit (HDU) of our trauma center.

Materials and Methods:

All the isolates of beta hemolytic Streptococci were identified by standard microbiological methods, Vitek 2 system and latex agglutination tests. Antimicrobial susceptibility testing was performed as recommended by Clinical Laboratory Standards Institute. Exotoxin genes, including speA, speB, speC, speF, smeZ, ssa, speG, speH, speJ, speL, speM and speI were detected by polymerase chain reaction (PCR). The emm types of isolates of S. pyogenes were determined by sequencing the variable 5’ end of emm gene after amplification by PCR.

Results:

In a 28 bedded poly-trauma ward with a four bedded HDU three out of four patients developed S. pyogenes emm type 58 infection. The strain was macrolide and tetracycline resistant and produced the Streptococcal pyrogenic exotoxins speB, speC, speG, speF and smeZ. Surveillance sampling was done for investigation from patients, health-care workers and environmental samples.

Conclusion:

An outbreak of GAS infections was established caused by the uncommonly reported emm type 58. The outbreak was controlled by prompt treatment, intensive surveillance, feedback and training.

Streptococcus pyogenes and re-emergence of scarlet fever as a public health problem

Explosive outbreaks of infectious diseases occasionally occur without immediately obvious epidemiological or microbiological explanations. Plague, cholera and Streptococcus pyogenes infection are some of the epidemic-prone bacterial infections. Besides epidemiological and conventional microbiological methods, the next-generation gene sequencing technology permits prompt detection of genomic and transcriptomic profiles associated with invasive phenotypes. Horizontal gene transfer due to mobile genetic elements carrying virulence factors and antimicrobial resistance, or mutations associated with the two component CovRS operon are important bacterial factors conferring survival advantage or invasiveness. The high incidence of scarlet fever in children less than 10 years old suggests that the lack of protective immunity is an important host factor. A high population density, overcrowded living environment and a low yearly rainfall are environmental factors contributing to outbreak development. Inappropriate antibiotic use is not only ineffective for treatment, but may actually drive an epidemic caused by drug-resistant strains and worsen patient outcomes by increasing the bacterial density at the site of infection and inducing toxin production. Surveillance of severe S. pyogenes infection is important because it can complicate concurrent chickenpox and influenza. Concomitant outbreaks of these two latter infections with a highly virulent and drug-resistant S. pyogenes strain can be disastrous.

Creatine kinase as an indicator for hysterectomy in postpartum endomyometritis due to group A streptococci: a hypothesis illustrated by a case report

BACKGROUND

Puerperal group A streptococcus (GAS) infection, once the leading cause of postpartum sepsis, has been increasing again since the 1980s. Streptococcal toxic shock syndrome (STSS) is a serious complication characterized by rapidly spreading GAS infection, shock, and multiple organ failure. Immediate recognition and implementation of therapy is crucial for survival. Making informed decisions regarding surgical debridement, namely hysterectomy, based on clinical indicators is difficult for practitioners.

OBJECTIVES

This article discusses the potential role of creatine kinase in the decision-making process for treatment of STSS, particularly with regard to hysterectomy.

MATERIAL AND METHODS

A case report is presented. The literature was searched using the key words 'group A streptococcus', 'postpartum hysterectomy', 'creatine kinase', 'endomyometritis', and 'streptococcal toxic shock syndrome' in PubMed and the UptoDate database. Relevant articles published between 1991 and 2011 were evaluated.

CONCLUSION

Decisions regarding hysterectomy in STSS management are difficult. A rise in CK levels in the serum may indicate involvement of the myometrium and may be an important parameter in the difficult decision of hysterectomy when treating STSS.

Epidemiology of invasive Streptococcus pyogenes infections in France in 2007

Invasive group A streptococcal (GAS) infections cause significant morbidity and mortality. A national survey was initiated to assess the burden of invasive GAS infections in France, describe their clinical characteristics, and assess the molecular characteristics of GAS strains responsible for these infections. The survey was conducted in 194 hospitals, accounting for 51% of acute care hospital admissions in France. Clinical data, predisposing factors, and demographic data were obtained, and all GAS isolates were emm sequence typed. We identified 664 cases of invasive GAS infections, with an annual incidence of 3.1 per 100,000 population. The case-fatality ratio was 14% and rose to 43% in the case of streptococcal toxic shock syndrome. Bacteremia without identified focus (22%) and skin/soft tissue infections (30%) were the most frequent clinical presentations. Necrotizing fasciitis was frequent in adults (18%) and uncommon in children (3%). The 3 predominant emm types were emm1, emm89, and emm28, accounting for 33%, 16%, and 10% of GAS isolates, respectively. The emm1 type was associated with fatal outcomes and was more frequent in children than in adults. Six clusters of cases were identified, with each cluster involving 2 invasive cases due to GAS strains which shared identical GAS emm sequence types. Four clusters of cases involved eight postpartum infections, one family cluster involved a mother and child, and one cluster involved two patients in a nursing home. Invasive GAS infection is one of the most severe bacterial diseases in France, particularly in persons aged ≥ 50 years or when associated with toxic shock syndrome.

Molecular pathogenesis of necrotizing fasciitis

Necrotizing fasciitis, also known as the flesh-eating disease, is a severe invasive infection associated with very high rates of human morbidity and mortality. It is most commonly caused by group A Streptococcus(GAS), a versatile human pathogen that causes diseases ranging in severity from uncomplicated pharyngitis (or strep throat) to life-threatening infections such as necrotizing fasciitis. Herein, we review recent discoveries bearing on the molecular pathogenesis of GAS necrotizing fasciitis. Importantly, the integration of new technologies and the development of human-relevant animal models have markedly expanded our understanding of the key pathogen-host interactions underlying GAS necrotizing fasciitis. For example, we now know that GAS organisms secrete a variety of proteases that disrupt host tissue and that these proteolytic enzymes are regulated by multiple transcriptional and posttranslational processes. This pathogenesis knowledge will be crucial to supporting downstream efforts that seek to develop novel vaccines and therapeutic agents for this serious human infection.

Clinical and epidemiological aspects of invasive Streptococcus pyogenes infections in Denmark during 2003 and 2004

Active surveillance of invasive group A streptococcal (GAS) infections was conducted in Denmark during 2003 and 2004 as a part of the Strep-EURO initiative. The main objective was to improve understanding of the epidemiology of invasive GAS disease in Denmark. During the 2 years, 278 cases were reported, corresponding to a mean annual incidence of 2.6 cases per 100,000 inhabitants. The vast majority of isolates, 253 (91%), were from blood, with the remaining 25 (9%) being from cerebrospinal fluid, joints, or other normally sterile sites. The mean case fatality rate (CFR) was 20%, with the rate being higher in patients more than 70 years of age (36.5%). For streptococcal toxic shock syndrome (STSS) and necrotizing fasciitis the CFRs were 53% and 25%, respectively. Out of 16 T types recorded, three predominated: T28 (23%), T1 (22%), and the cluster T3/13/B3264 (14%). Among 29 different emm types, emm28 and emm1 accounted for 51% of strains, followed by emm3 (11%), emm89 (7%), and emm12 (5.5%). Low resistance rates were detected for macrolide-lincosamide-streptogramin B (MLS(B)) antibiotics (3%) and tetracycline (8%); two isolates exhibited coresistance to tetracycline and macrolides. Of nine pyrogenic exotoxin (superantigen) genes examined, speA and speC were identified in 58% and 40% of the strains, respectively; either of the genes was present in all strains causing STSS. Most strains harbored speG (99%). ssa was present in 14% of the isolates only. In Denmark, as in comparable countries, GAS invasive disease shows a sustained, high endemicity, with involvement of both established and emerging streptococcal emm and T types.

Severe skin and soft tissue infections and associated critical illness

Skin and soft tissue infections (SSTIs) span a broad spectrum of clinical entities from limited cellulitis to rapidly progressive necrotizing fasciitis, which may be associated with septic shock or a toxic shock-like syndrome. These infections may manifest initially as pyodermas that then progress; alternatively, they may arise from metastatic spread of microorganisms from a distant focus. Regardless of the source, SSTIs may lead to critical illness. The complex interplay of environment, host, and pathogen are important to consider when evaluating SSTIs and planning appropriate therapy. The keys to a successful outcome are early identification of risk factors for specific pathogens and early initiation of empiric antimicrobial therapy. For certain types of SSTIs, surgical intervention for diagnosis and/or therapy is also required.