title: MRSA Pediatric clone expressing ermC plus lnuA genes causing nosocomial transmission and healthcare workers colonization in a neonatal intensive care unit.
abstract: Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of both nosocomial and community-acquired infections. We describe an outbreak caused by the MRSA Pediatric clone expressing an unusual lincosamide resistant phenotype. Between January and May 2006, an MRSA outbreak was detected at the Neonatal Unit of Hospital Interzonal General de Agudos "Evita", Buenos Aires Province, Argentina that affected ten patients. Seven isolates from seven patients plus five MRSA recovered from health care workers (nasal carriage) were studied. Two phenotypes were observed: (i) ELCi (10), resistance to erythromycin and lincomycin and inducible resistance to clindamycin; (ii) ELiCi (2), resistance to erythromycin and inducible resistance to lincomycin and clindamycin. All 12 MRSA were resistant to oxacillin, erythromycin and gentamicin. Isolates expressing the ELCi-phenotype showed lincomycin MIC values between 16 and 32mg/L, while the remaining 2 isolates with ELiCi-phenotype presented a MIC value of 0.5mg/L. No differences were observed between the clindamycin MIC values in both phenotypes, ranging 0.25-0.5mg/L. Isolates showing ELCi-phenotype harbored ermC plus lnuA genes, and the other two only ermC gene. All 12 isolates were genetically related and belonged to the Pediatric clone (ST100) harboring a new variant of SCCmecIV. This is the first MRSA outbreak expressing an unusual ELCi phenotype due to a combination of ermC plus lnuA genes.
authors.affiliation: Servicio Antimicrobianos, Dpto. Bacteriología, Instituto Nacional de Enfermedades Infecciosas - ANLIS "Dr. Carlos G. Malbrán", Buenos Aires, Argentina.
authors.forename: Diego
authors.initials: D
authors.lastname: Faccone
authors.affiliation: Hospital Interzonal General de Agudos "Evita", Buenos Aires, Argentina.
authors.forename: Ana M
authors.initials: AM
authors.lastname: Togneri
authors.affiliation: Hospital Interzonal General de Agudos "Evita", Buenos Aires, Argentina.
authors.forename: Laura
authors.initials: L
authors.lastname: Podesta
authors.affiliation: Hospital Interzonal General de Agudos "Evita", Buenos Aires, Argentina.
authors.forename: Marcela
authors.initials: M
authors.lastname: Perez
authors.affiliation: Servicio Antimicrobianos, Dpto. Bacteriología, Instituto Nacional de Enfermedades Infecciosas - ANLIS "Dr. Carlos G. Malbrán", Buenos Aires, Argentina.
authors.forename: Paula
authors.initials: P
authors.lastname: Gagetti
authors.affiliation: Hospital Interzonal General de Agudos "Evita", Buenos Aires, Argentina.
authors.forename: Susana
authors.initials: S
authors.lastname: Sanchez
authors.affiliation: Hospital Interzonal General de Agudos "Evita", Buenos Aires, Argentina.
authors.forename: Graciela
authors.initials: G
authors.lastname: Romero
authors.affiliation: Servicio Antimicrobianos, Dpto. Bacteriología, Instituto Nacional de Enfermedades Infecciosas - ANLIS "Dr. Carlos G. Malbrán", Buenos Aires, Argentina. Electronic address: acorso@anlis.gov.ar.
authors.forename: Alejandra
authors.initials: A
authors.lastname: Corso
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003428:Cross Infection / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission; D004196:Disease Outbreaks; D024901:Drug Resistance, Multiple, Bacterial / Q000187:drug effects; D014644:Genetic Variation; D006801:Humans; D007231:Infant, Newborn; D017758:Infectious Disease Transmission, Patient-to-Professional; D007363:Intensive Care Units, Neonatal; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects / Q000302:isolation & purification / Q000378:metabolism*; D008826:Microbial Sensitivity Tests; D010348:Patient Care Team; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000382:microbiology / Q000635:transmission*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins
keywords: MRSA; Neonatal; Outbreak; lnuA