Outbreak report of investigation and control of an outbreak of Panton-Valentine Leukocidin-positive methicillin-sensitive Staphylococcus aureus (PVL-MSSA) infection in neonates and mothers.

BACKGROUND: In January 2011, there was an outbreak of Panton-Valentine Leukocidin-positive methicillin-sensitive Staphylococcus aureus (PVL-MSSA) infection in a neonatal unit (NNU). We describe the investigation and control of an outbreak of PVL-MSSA infection in neonates. SETTING: Neonatal unit in West London. METHODS: We performed descriptive and analytical (case-control study) epidemiological investigations. Microbiological investigations including screening of MSSA isolates by PCR for the presence of the luk-PV, mecA and mecC genes and comparison of isolate with Pulsed field gel electrophoresis (PFGE). Control measures were also introduced. RESULTS: Sixteen babies were infected/colonised with the outbreak strain. Of these, one baby developed blood stream infection, 12 developed skin pustules and four babies were colonised. Four mothers developed breast abscesses. Eighty-seven babies in the unit were screened and 16 were found to have same PVL-MSSA strain (spa type t005, belonging to MLST clonal complex 22). Multivariate analysis showed gestational age was significantly lower in cases compared to controls (mean gestational age: 31.7 weeks v 35.6 weeks; P = 0.006). Length of stay was significantly greater for cases, with a median of 25 days, compared to only 6 days for controls (P = 0.01). Most (88%) cases were born through caesarean section, compared to less than half of controls. (P = 0.002). No healthcare worker carriers and environmental source was identified. The outbreak was controlled by stopping new admissions to unit and reinforcing infection control precautions. The outbreak lasted for seven weeks. No further cases were reported in the following year. CONCLUSIONS: Infection control teams have to be vigilant for rising prevalence of particular S. aureus clones in their local community as they may cause outbreaks in vulnerable populations in healthcare settings such as NNUs.

Outcome of a screening programme for the prevention of neonatal invasive early-onset group B Streptococcus infection in a UK maternity unit: an observational study.

BACKGROUND: Against a background of failure to prevent neonatal invasive early-onset group B Streptococcus infections (GBS) in our maternity unit using risk-based approach for intrapartum antibiotic prophylaxis, we introduced an antenatal GBS carriage screening programme to identify additional women to target for prophylaxis. OBJECTIVES: To describe the implementation and outcome of an antepartum screening programme for prevention of invasive early-onset GBS infection in a UK maternity unit. DESIGN: Observational study of outcome of screening programme (intervention) with comparison to historical controls (preintervention). SETTING: Hospital and community-based maternity services provided by Northwick Park and Central Middlesex Hospitals in North West London. PARTICIPANTS: Women who gave birth between March 2014 and December 2015 at Northwick Park Hospital. METHODS: Women were screened for GBS at 35-37 weeks and carriers offered intrapartum antibiotic prophylaxis. Screening programme was first introduced in hospital (March 2014) and then in community (August 2014). Compliance was audited by review of randomly selected case records. Invasive early-onset GBS infections were defined through GBS being cultured from neonatal blood, cerebrospinal fluid or sterile fluids within 0-6 days of birth. MAIN OUTCOME: Incidence of early-onset GBS infections. RESULTS: 6309 (69%) of the 9098 eligible women were tested. Screening rate improved progressively from 42% in 2014 to 75% in 2015. Audit showed that 98% of women accepted the offer of screening. Recto-vaginal GBS carriage rate was 29.4% (1822/6193). All strains were susceptible to penicillin but 11.3% (206/1822) were resistant to clindamycin. Early onset GBS rate fell from 0.99/1000 live births (25/25276) in the prescreening period to 0.33/1000 in the screening period (Rate Ratio=0.33; p=0.08). In the subset of mothers actually screened, the rate was 0.16/1000 live births (1/6309), (Rate Ratio=0.16; p<0.05). CONCLUSIONS: Our findings confirm that an antenatal screening programme for prevention of early-onset GBS infection can be implemented in a UK maternity setting and is associated with a fall in infection rates.