Eurosurveillance - Volume 19, Issue 33, 21 August 2014

Staphylococcal scalded skin syndrome (SSSS) is a blistering skin condition caused by exfoliative toxin-producing strains of Staphylococcus aureus. Outbreaks of SSSS in maternity settings are rarely reported. We describe an outbreak of SSSS that occurred among neonates born at a maternity unit in England during December 2012 to March 2013. Detailed epidemiological and microbiological investigations were undertaken. Eight neonates were found to be infected with the outbreak strain of S. aureus, of spa type t346, representing a single pulsotype. All eight isolates contained genes encoding exfoliative toxin A (eta) and six of them contained genes encoding toxin B (etb). Nasal swabs taken during targeted staff screening yielded a staphylococcal carriage rate of 21% (17/80), but none contained the outbreak strain. Mass screening involving multi-site swabbing and pooled, enrichment culture identified a healthcare worker (HCW) with the outbreak strain. This HCW was known to have a chronic skin condition and their initial nasal screen was negative. The outbreak ended when they were excluded from work. This outbreak highlights the need for implementing robust swabbing and culture methods when conventional techniques are unsuccessful in identifying staff carrier(s). This study adds to the growing body of evidence on the role of HCWs in nosocomial transmission of S. aureus.

A mumps outbreak reported from the Federation of Bosnia and Herzegovina involved 7,895 cases between December 2010 and September 2012. This was the largest outbreak in the country since the introduction of the measles, mumps and rubella vaccine in 1980. The highest disease incidence was found among 15 to 19 year-olds. About 39% (3,050/7,895) of cases reported to be unvaccinated; the vaccination status of 31% (2,426/7,895) was unknown. A seroprevalence study among 150 asymptomatic contacts to mumps cases showed that about one third (45/150) were susceptible to mumps. Among 105 clinically suspected mumps patients hospitalised at the Clinical Centre of the University of Sarajevo, orchitis (60% of all males: 51/85) and meningitis (9%: 9/105) were the most common complications. Among 57 outbreak sequences obtained for the small hydrophobic gene, eight different variants of genotype G viruses were identified. The outbreak affected mainly age groups comprising individuals who were not vaccinated during or after the Bosnian war, as well as cantons with single dose immunisation policies until 2001. In addition to issues related to vaccination of individuals, differential responses to vaccines and vaccine strains, waning of antibodies and potentially also the genetically diverse variants of genotype G may have compounded the size and duration of the outbreak. Our report emphasizes the need for supplementary immunisation programmes in particular for adolescents and young adults.

Pathogen adaptation has been proposed to contribute to the resurgence of pertussis. A striking recent example is the emergence of isolates deficient in the vaccine component pertactin (Prn). This study explores the emergence of such Prn-deficient isolates in six European countries. During 2007 to 2009, 0/83 isolates from the Netherlands, 0/18 from the United Kingdom, 0/17 Finland, 0/23 Denmark, 4/99 Sweden and 5/20 from Norway of the isolates collected were Prn-deficient. In the Netherlands and Sweden, respectively 4/146 and 1/8 were observed in a later period (2010-12). The Prn-deficient isolates were genetically diverse and different mutations were found to inactivate the prn gene. These are indications that Prn-deficiency is subject to positive selective pressure. We hypothesise that the switch from whole cell to acellular pertussis vaccines has affected the balance between 'costs and benefits' of Prn production by Bordetella pertussis to the extent that isolates that do not produce Prn are able to expand. The absence of Prn-deficient isolates in some countries may point to ways to prevent or delay the spread of Prn-deficient strains. In order to substantiate this hypothesis, trends in the European B. pertussis population should be monitored continuously. .