Estimation of the force of infection and infectious period of skin sores in remote Australian communities using interval-censored data.

Prevalence of impetigo (skin sores) remains high in remote Australian Aboriginal communities, Fiji, and other areas of socio-economic disadvantage. Skin sore infections, driven primarily in these settings by Group A Streptococcus (GAS) contribute substantially to the disease burden in these areas. Despite this, estimates for the force of infection, infectious period and basic reproductive ratio-all necessary for the construction of dynamic transmission models-have not been obtained. By utilising three datasets each containing longitudinal infection information on individuals, we estimate each of these epidemiologically important parameters. With an eye to future study design, we also quantify the optimal sampling intervals for obtaining information about these parameters. We verify the estimation method through a simulation estimation study, and test each dataset to ensure suitability to the estimation method. We find that the force of infection differs by population prevalence, and the infectious period is estimated to be between 12 and 20 days. We also find that optimal sampling interval depends on setting, with an optimal sampling interval between 9 and 11 days in a high prevalence setting, and 21 and 27 days for a lower prevalence setting. These estimates unlock future model-based investigations on the transmission dynamics of skin sores.

Whole genome sequencing reveals extensive community-level transmission of group A Streptococcus in remote communities.

Impetigo is common in remote Indigenous children of northern Australia, with the primary driver in this context being Streptococcus pyogenes [or group A Streptococcus (GAS)]. To reduce the high burden of impetigo, the transmission dynamics of GAS must be more clearly elucidated. We performed whole genome sequencing on 31 GAS isolates collected in a single community from children in 11 households with ⩾2 GAS-infected children. We aimed to determine whether transmission was occurring principally within households or across the community. The 31 isolates were represented by nine multilocus sequence types and isolates within each sequence type differed from one another by only 0-3 single nucleotide polymorphisms. There was evidence of extensive transmission both within households and across the community. Our findings suggest that strategies to reduce the burden of impetigo in this setting will need to extend beyond individual households, and incorporate multi-faceted, community-wide approaches.

Notes from the field: outbreak of skin lesions among high school wrestlers--Arizona, 2014.

Skin infections are a common problem among athletes at all levels of competition; among wrestlers, 8.5% of all adverse events are caused by skin infections. Wrestlers are at risk because of the constant skin-to-skin contact required during practice and competition. The most common infections transmitted among high school wrestlers include fungal infections (e.g., ringworm), the viral infection herpes gladiatorum caused by herpes simplex virus-1 (HSV-1), and bacterial infections (e.g., impetigo) caused by Staphylococcus or Streptococcus species, including methicillin-resistant Staphylococcal aureus (MRSA). On February 7, 2014, the Maricopa County Department of Public Health was notified of multiple wrestlers who reported skin lesions 2 weeks after participating in a wrestling tournament at school A. The tournament was held on January 24-25 and included 168 wrestlers representing 24 schools. The county health department initiated an investigation to identify cases of skin lesion, determine lesion etiology, identify risks associated with lesion development, and provide guidance for preventing additional cases.

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.

Spread of a methicillin-resistant Staphylococcus aureus ST80-IV clone in a Danish community.

OBJECTIVE: We report a community cluster of methicillin-resistant Staphylococcus aureus (MRSA) in Denmark with emphasis on routes of transmission and infection control measures. The objective is to extend knowledge of MRSA in a community setting where a nosocomial link could effectively be ruled out. DESIGN: Population-based observational study from November 1997 until June 2003. SETTING: North Jutland County, with approximately 495,000 inhabitants. SUBJECTS: The cluster encompassed 46 individuals and 26 households. INTERVENTIONS: Infection control measures included repeated visits to affected households by an infection control nurse who undertook screening for carriage among all household members and provided a program for decolonization. RESULTS: The causal strain was identical to a newly described international clone, ST80; SSCmec type IV; and Panton-Valentine leukocidin positive. Plausible routes of transmission included household contact and contact at work, kindergarten, and school. We did not detect a nosocomial source or any secondary cases in hospitals. Transmission by healthcare contact outside the hospital was plausible for three cases. We found evidence that the clone was introduced on more than one occasion to immigrant families from the Middle East. A 5-day decolonization program was successful at first attempt in 15 of 16 households that could be evaluated. CONCLUSIONS: Despite the described infection control measures, we continued to see new cases, underlining a need for a national policy to contain MRSA in the community.

Prevalence of staphylococcal zoonosis in pyogenic skin infections.

S. aureus aetiology was found in 76.47% of the 102 pyoderma cases under study, with a high frequency of incidence in children below 5 years of age. The majority of the S. aureus isolates was nontypable (50.0%) and among the typable strains, phage group-III (31.0%), Group-I (20.7%) and a mixed phage group (34.5%) were predominant. 28.2% of the isolates were S. aureus var. bovis and 2.6% were S. aureus var. canis subgroups. Zoonoses in staphylococcal pyogenic skin infections were proved in 9 of the cases, which showed the history of direct animal contact supported by the isolation of S. aureus of animal host origin. Dogs, cattle and poultry were found to be the most important reservoirs transmitting S. aureus to humans, with folliculitis, furunculosis, impetigo as the frequent clinical manifestations.

Aspectos epidemiológicos da colonizaçäo hospitalar de Staphylococcus aureus em recém-nascidos tendo em vista a prevençäo de surtos de impetigo / Epidemiological aspects of the hospital colonization of Staphylococcus aureus in newborn infants, in consequence of impetigo outbreaks prevention

Confirmou-se o papel relavante das mäos como veículo de transmissäo de cepas de S. aureus em Berçario, conseqüente à negligência na sua lavagem. A fagotipagem revelou existência de elevado percentual de elementos do "staff" do Berçário do H.C.F.M.R.P. - U.S.P. albergando e veinculando cepas consideradas em epidemias hospitalares. Os casos de impetigo estudados sugerem que podem ser múltiplas as fontes humanas de transmissäo de S. aureus, e que cepas consideradas näo hospitalares também podem estar relacionadas com surtos de impetigo