Identification of a Novel Methicillin-Resistant Staphylococcus aureus Epidemic Clone in Córdoba, Argentina, Involved in Nosocomial Infections

Abstract

Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are increasingly a main health concern worldwide for hospitalized patients. In addition, the prevalence of community-acquired infection has risen continuously during the last few years. Some MRSA clones spread easier than others within the hospital environment and therefore are frequently implicated in outbreaks. Thus, the spread of a unique epidemic multiresistant clone, the so-called South American clone, is the main cause of nosocomial infections produced by this bacterium in Brazil and in some regions of Argentina, Chile, and Uruguay. In the present work we describe the identification of a novel clone of MRSA that is involved in nosocomial infections and that shows a prevalence as high as that for the South American clone. A total of 53 consecutive single-patient MRSA isolates were recovered during a 3-month period (May to July 1999) from six different hospitals (955 beds) in Córdoba. The isolates were initially typed according the antibiotic resistance and phage susceptibility patterns, followed by genotyping using pulsed-field gel electrophoresis (PFGE). PFGE analysis of the 53 MRSA isolates revealed six major types (A to F) and 25 subtypes. The B-type DNA pattern was indistinguishable from that of the South American epidemic clone observed in 34% of the isolates. A novel highly prevalent clone, showing the A-type DNA pattern and representing 38% of the isolates, was also identified. Moreover, the most frequent subtype of the A clonal family triggered an outbreak in a hospital 2 months later, further confirming its epidemic feature.

Use of molecular epidemiology to monitor the nosocomial dissemination of methicillin-resistant Staphylococcus aureus in a University Hospital from 1991 to 2001

“…In England, the percentage increased from 1.5 to 13.2% between 1989 and 1995 (8)(9)(10)(11)(12)(13). In Brazil, the prevalence of MRSA is high, especially in large and teaching hospitals, ranging from 26.6 to 70%, and MRSA is considered to be the main pathogen causing hospital outbreaks (14)(15)(16)(17)(18).…”

Molecular Characterization of Methicillin-Resistant Staphylococcus aureus Isolates Collected in Asunción, Paraguay

“…Hence, the major MRSA clone detected in Hospital de Clinicas (Paraguay) corresponded to the Cordobes/Chilean clone. In Cordoba (Argentina), the Cordobes/Chilean clone started to replace the Brazilian clone in 1999 (14) and became predominant in 2001.…”

Frecuencia de genes que codifican factores de virulencia en Staphylococcus aureus aislados de niños que concurrieron al Hospital General Pediátrico Niños de Acosta Ñú, durante el año 2010

“…El Paraguay no cuenta con datos epidemiológicos que indiquen si las cepas de S. aureus que circulan en niños son portadoras de genes que codifican factores de virulencia, lo cual agravaría la infección causada por dicha bacteria. En el Instituto de Investigaciones en Ciencias de la Salud (IICS), se han iniciado estudios que han mostrado la portación del S. aureus en trabajadores de la salud del Hospital General Pediátrico Acosta Ñú (HGP) y arrojaron los primeros datos sobre caracterización molecular de aislados de S. aureus obtenidos a partir de muestras clínicas de niños, en los que se detectó la presencia del gen mecA y el codificante de la PVL (14)(15)(16).…”