A large outbreak of streptococcal pyoderma in a military training establishment

Housing Initiatives to Address Strep A Infections and Reduce RHD Risks in Remote Indigenous Communities in Australia

Group A Streptococcus (Strep A) skin infections (impetigo) can contribute to the development of acute rheumatic fever (ARF) and rheumatic heart disease (RHD). This is of particular concern for Indigenous residents of remote communities, where rates of ARF and RHD are much higher than their urban and non-Indigenous counterparts. There are three main potential Strep A transmission pathways: skin to skin, surface to skin, and transmission through the air (via droplets or aerosols). Despite a lack of scientific certainty, the physical environment may be modified to prevent Strep A transmission through environmental health initiatives in the home, identifying a strong role for housing. This research sought to provide an outline of identified household-level environmental health initiatives to reduce or interrupt Strep A transmission along each of these pathways. The identified initiatives addressed the ability to wash bodies and clothes, to increase social distancing through improving the livability of yard spaces, and to increase ventilation in the home. To assist with future pilots and evaluation, an interactive costing tool was developed against each of these initiatives. If introduced and evaluated to be effective, the environmental health initiatives are likely to also interrupt other hygiene-related infections.

Hiding in Plain Sight: Benefit of Abrasion and Laceration Swabs in Identification of Panton-Valentine Leucocidin (PVL)-Meticillin Resistant Staphylococcus aureus (MRSA) Colonisation in Military Personnel

Background Outbreaks of Panton-Valentine Leucocidin (PVL)-producing methicillin-resistant Staphylococcus aureus (MRSA) skin and soft tissue infections (SSTIs) are a recurrent challenge for the Royal Marines at the Commando Training Centre (CTCRM). The intensity of commando training, its impact on skin integrity, and persistent colonisation reservoirs within the training centre have thwarted attempts to prevent these outbreaks. Aim To present an outbreak of PVL-producing MRSA SSTIs at a military training centre, demonstrating the benefit of additional abrasion and laceration swabs on the identification of colonised personnel and showing the effectiveness of a 10-day decolonisation regime. Method Following the identification of the outbreak of PVL-producing MRSA, all 36 members of the Recruit Troop underwent nasal MRSA screening to identify MRSA carriers. The screening was repeated on day 16 after completing an enhanced 10-day decolonisation regime. A third screening was conducted on the 110th day after a second peak of infection was identified. Various infection control measures, such as enhanced cleaning, restriction of movement and adjustments to the military training serials, were introduced to prevent further spread through the training centre. Results In this outbreak, two-thirds (eighteen) of the Recruit Troop suffered MRSA-PVL skin infections requiring antibiotic therapy and three required hospital admission for surgical management of their abscesses. The outbreak lasted 130 days, with two spikes in infections 10 weeks apart. The outbreak was successfully confined to one troop. Conclusion With concerns about low identification rates of carriers using nasal screening for MRSA, in this outbreak, we improved the identification of asymptomatic carriage with the simple step of additional culture swabs for all cuts and abrasions. Improved identification of colonised recruits, along with an enhanced decolonisation regime and rigid infection control practices, prevented the further spread of the clone through the training centre. In a population with constant ongoing skin trauma, such as the military, contact sport athletes and iIV drug users, our results show that a culture of suitable abrasions/lacerations will improve the identification of MRSA colonisation compared with nasal swabs alone. Despite ongoing skin trauma and the logistical difficulties in delivering effective decolonisation during military training, decolonisation was successful in 79% of recruits after one decolonisation and 87% after the second 10-day decolonisation.

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 ).

The Association between Environmental Factors and Scarlet Fever Incidence in Beijing Region: Using GIS and Spatial Regression Models

(1) Background: Evidence regarding scarlet fever and its relationship with meteorological, including air pollution factors, is not very available. This study aimed to examine the relationship between ambient air pollutants and meteorological factors with scarlet fever occurrence in Beijing, China. (2) Methods: A retrospective ecological study was carried out to distinguish the epidemic characteristics of scarlet fever incidence in Beijing districts from 2013 to 2014. Daily incidence and corresponding air pollutant and meteorological data were used to develop the model. Global Moran’s I statistic and Anselin’s local Moran’s I (LISA) were applied to detect the spatial autocorrelation (spatial dependency) and clusters of scarlet fever incidence. The spatial lag model (SLM) and spatial error model (SEM) including ordinary least squares (OLS) models were then applied to probe the association between scarlet fever incidence and meteorological including air pollution factors. (3) Results: Among the 5491 cases, more than half (62%) were male, and more than one-third (37.8%) were female, with the annual average incidence rate 14.64 per 100,000 population. Spatial autocorrelation analysis exhibited the existence of spatial dependence; therefore, we applied spatial regression models. After comparing the values of R-square, log-likelihood and the Akaike information criterion (AIC) among the three models, the OLS model (R² = 0.0741, log likelihood = −1819.69, AIC = 3665.38), SLM (R² = 0.0786, log likelihood = −1819.04, AIC = 3665.08) and SEM (R² = 0.0743, log likelihood = −1819.67, AIC = 3665.36), identified that the spatial lag model (SLM) was best for model fit for the regression model. There was a positive significant association between nitrogen oxide (p = 0.027), rainfall (p = 0.036) and sunshine hour (p = 0.048), while the relative humidity (p = 0.034) had an adverse association with scarlet fever incidence in SLM. (4) Conclusions: Our findings indicated that meteorological, as well as air pollutant factors may increase the incidence of scarlet fever; these findings may help to guide scarlet fever control programs and targeting the intervention.

Bromine, bear-claw scratch fasciotomies, and the Eagle effect: management of group A streptococcal necrotising fasciitis and its association with trauma

Necrotising fasciitis is a rare, but potentially fatal, soft-tissue infection. Historical depictions of the disease have been described since classical times and were mainly recorded in wartime reports of battle injuries. Although several different species of bacteria can cause necrotising fasciitis, perhaps the most widely known is group A streptococcus (GAS). Infection control, early surgical debridement, and antibiotic therapy are now the central tenets of the clinical management of necrotising fasciitis; these treatment approaches all originate from those used in wars in the past 150 years. We review reports from the 19th century, early 20th century, and mid-20th century onwards to show how the management of necrotising fasciitis has progressed in parallel with prevailing scientific thought and medical practice. Historically, necrotising fasciitis has often, but not exclusively, been associated with penetrating trauma. However, along with a worldwide increase in invasive GAS disease, recent reports have cited cases of necrotising fasciitis following non-combat-related injuries or in the absence of antecedent events. We also investigate the specific association between GAS necrotising fasciitis and trauma. In the 21st century, molecular biology has improved our understanding of GAS pathogenesis, but has not yet affected attributable mortality.

Fabric-skin models to assess infection transfer for impetigo contagiosa in a kindergarten scenario

Children in community bodies like kindergartens are predisposed to suffer from impetigo. To consider important measures for infection prevention, direct and indirect transmission routes of pathogens must be revealed. Therefore, we studied the role of skin and fabrics in the spread of the impetigo pathogen Staphylococcus aureus and the strain Streptococcus equi (surrogate to Streptococcus pyogenes) in order to assess infection transfer in realistic scenarios. The transmission of test strains was studied with standardized fabric-skin models using a technical artificial skin and fabrics of different fiber types commonly occurring in German kindergartens. In synthetic pus, both test strains persisted on artificial skin and fabrics for at least 4 h. Friction enhanced transfer, depending on the fiber type or fabric construction. In a skin-to-skin setup, the total transfer was higher than via fabrics and no decrease in the transmission rates from donor to recipients could be observed after successive direct skin contacts. Children in kindergartens may be at risk of transmission for impetigo pathogens, especially via direct skin contact, but also by the joint use of fabrics, like towels or handicraft materials. Fabric-skin models used in this study enable further insight into the transmission factors for skin infections on the basis of a practical approach.

Skin and soft tissue infections in the military

Skin and soft tissue infections (SSTI) are common in military populations regularly living and training in close contact with each other. The majority of such infections are simple and can be easily treated with antibiotics and appropriate infection control practices. Some, however, can progress to become complex and even life threatening, such as Panton-Valentine Leukocidin (PVL)-associated staphylococcus aureus pneumonia, or Streptococcus pyogenes necrotising fasciitis, which carry a mortality rate of up to 65% and 30%, respectively. This review focuses on the most important SSTIs and those more commonly affecting military personnel with advice on how they are best managed.

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.