Panton–Valentine leukocidin-positive methicillin-resistant Staphylococcus aureus outbreak among healthcare workers in a long-term care facility

• Published in: International journal of infectious diseases 2009-11, Vol.13 (6), p.e401-e406
• Main Authors: Maltezou, H.C, Vourli, S, Katerelos, P, Maragos, A, Kotsalidou, S, Remoudaki, E, Papadimitriou, T, Vatopoulos, A.C
• Format: Article
• Language: English
• Subjects: Adult; Bacterial Toxins - genetics; Bacterial Toxins - metabolism; Carrier State - epidemiology; Carrier State - microbiology; Case-Control Studies; Disease Outbreaks; Exotoxins - genetics; Exotoxins - metabolism; Female; Health Personnel - statistics & numerical data; Healthcare workers; Humans; Infectious Disease; Interviews as Topic; Leukocidins - genetics; Leukocidins - metabolism; Long-Term Care; Long-term care facility; Male; Methicillin-Resistant Staphylococcus aureus - classification; Methicillin-Resistant Staphylococcus aureus - drug effects; Methicillin-Resistant Staphylococcus aureus - genetics; Methicillin-Resistant Staphylococcus aureus - isolation & purification; Middle Aged; MRSA; Nose - microbiology; Outbreak; Panton–Valentine leukocidin; Pulmonary/Respiratory; Risk Factors; Staphylococcal Infections - epidemiology; Staphylococcal Infections - microbiology
• ISSN: 1201-9712; 1878-3511
• DOI: 10.1016/j.ijid.2009.02.004

Summary Background We investigated an outbreak of community-acquired methicillin-resistant Staphylococcus aureus (MRSA) infections that occurred among healthcare workers (HCWs) but not among residents of a long-term care facility (LTCF). Methods Cases of S. aureus infection were sought by reviewing the medical records of residents and HCWs. In order to identify risk factors for the development of an S. aureus infection, an unmatched case–control study was conducted. Cases were all HCWs with a clinically compatible S. aureus infection; controls were HCWs with no history of a clinically compatible S. aureus infection. Cases and controls were interviewed and anterior nasal swabs were collected. Results Over a period of 14 months, a total of eight cases were identified among practice nurses, giving an attack rate of 10% for this category of profession. All isolates were identified as MRSA Panton–Valentine leukocidin (PVL)-producing SCC mec type IV. By multivariate analysis, working in a specific zone and being a practice nurse were found to be statistically significant risk factors for infection. Conclusions The current outbreak indicates that HCWs may serve as vehicles for the entry of PVL-positive MRSA strains from the community into LTCFs, and that deficient hygiene practices and unrecognized carriage may facilitate spread. Given the increasing prevalence of PVL-positive MRSA infections worldwide, guidelines for the eradication of PVL-positive MRSA carriage within closed communities should be established and efforts to obtain cultures from compatible infections should be made.