Spread of Epidemic MRSA-ST5-IV Clone Encoding PVL as a Major Cause of Community Onset Staphylococcal Infections in Argentinean Children

Abstract

BackgroundCommunity-associated methicillin-resistant Staphylococcus aureus-(CA-MRSA) strains have emerged in Argentina. We investigated the clinical and molecular evolution of community-onset MRSA infections (CO-MRSA) in children of Córdoba, Argentina, 2005–2008. Additionally, data from 2007 were compared with the epidemiology of these infections in other regions of the country.Methodology/Principal FindingsTwo datasets were used: i) lab-based prospective surveillance of CA-MRSA isolates from 3 Córdoba pediatric hospitals-(CBAH1-H3) in 2007–2008 (compared to previously published data of 2005) and ii) a sampling of CO-MRSA from a study involving both, healthcare-associated community-onset-(HACO) infections in children with risk-factors for healthcare-associated infections-(HRFs), and CA-MRSA infections in patients without HRFs detected in multiple centers of Argentina in 2007. Molecular typing was performed on the CA-MRSA-(n: 99) isolates from the CBAH1-H3-dataset and on the HACO-MRSA-(n: 51) and CA-MRSA-(n: 213) isolates from other regions. Between 2005–2008, the annual proportion of CA-MRSA/CA-S. aureus in Córdoba hospitals increased from 25% to 49%, P<0.01. Total CA-MRSA infections increased 3.6 fold-(5.1 to 18.6 cases/100,000 annual-visits, P<0.0001), associated with an important increase of invasive CA-MRSA infections-(8.5 fold). In all regions analyzed, a single genotype prevailed in both CA-MRSA (82%) and HACO-MRSA(57%), which showed pulsed-field-gel electrophoresis-(PFGE)-type-“I”, sequence-type-5-(ST5), SCCmec-type-IVa, spa-t311, and was positive for PVL. The second clone, pulsotype-N/ST30/CC30/SCCmecIVc/t019/PVL+, accounted for 11.5% of total CA-MRSA infections. Importantly, the first 4 isolates of Argentina belonging to South American-USA300 clone-(USA300/ST8/CC8/SCCmecIVc/t008/PVL+/ACME−) were detected. We also demonstrated that a HA-MRSA clone-(pulsotype-C/ST100/CC5) caused 2% and 10% of CA-MRSA and HACO-MRSA infections respectively and was associated with a SCCmec type closely related to SCCmecIV(2B&5).Conclusions/SignificanceThe dissemination of epidemic MRSA clone, ST5-IV-PVL+ was the main cause of increasing staphylococcal community-onset infections in Argentinean children (2003–2008), conversely to other countries. The predominance of this clone, which has capacity to express the h-VISA phenotype, in healthcare-associated community-onset cases suggests that it has infiltrated into hospital-settings.

Genetic Characterization of a Vancomycin-Resistant Staphylococcus aureus Isolate from the Respiratory Tract of a Patient in a University Hospital in Northeastern Iran

“…This finding is consistent with most other hospitalacquired MRSA (HA-MRSA) strains that are negative for the pvl gene. This toxin is related to SCCmec types IV and V which are representative for community-acquired MRSA (CA-MRSA) (32). In most previous cases of VRSA isolation, VRE strains were also isolated (26,40).…”

In Vitro Activity of Ceftaroline against Staphylococcus aureus Isolates Collected in 2012 from Latin American Countries as Part of the AWARE Surveillance Program

“…A possible relationship with this sequence type and increased resistance to these drug classes would require more extensive typing and analysis. However, molecular studies of Latin American S. aureus, from Argentina in particular, have documented an epidemic spread of the MRSA ST-5-IV clone (37,38). MSSA ( Ceftaroline fosamil is a useful addition to the antimicrobial agents that can be used to treat S. aureus infections, especially with the capability of covering MRSA, including CA-MRSA.…”

Infecciones de piel y partes blandas en pediatría: consenso sobre diagnóstico y tratamiento

“…11,16,17,38 Si bien los genes que codifican la resistencia a meticilina de las cepas hospitalarias y comunitarias son los mismos, el casete cromosómico en el cual van integrados esos genes es diferente, lo que indica que estas cepas surgen en la comunidad y no representan una diseminación de las cepas hospitalarias. 12,30,34,39 Asimismo, las cepas de la comunidad presentan, además, la expresión de una exotoxina, llamada Panton-Valentine, vinculada a la invasividad, a l a t r o m b o f l e b i t i s y a l c o m p r o m i s o pulmonar.…”

“…12,30,34,39 Asimismo, las cepas de la comunidad presentan, además, la expresión de una exotoxina, llamada Panton-Valentine, vinculada a la invasividad, a l a t r o m b o f l e b i t i s y a l c o m p r o m i s o pulmonar. 11,15,16,34,39 Otros agentes que también pueden producir celulitis son Streptococcus agalactiae (SBHGB) y bacilos gram negativos en recién nacidos, y enterobacterias, micobacterias y hongos en huéspedes inmunocomprometidos.…”

“…40 Los SAMR-co que presentan la exotoxina llamada Panton-Valentine (PVL) + son vinculados más frecuentemente con infecciones más graves, como neumonía necrotizante y tromboflebitis. 15,16,39,41 7. Tratamiento: el tratamiento de la celulitis en huéspedes inmunocompetentes con trauma precedente debería incluir un antibiótico con actividad contra S. aureus y SBHGA.…”