Heterogeneous vancomycin-intermediate susceptibility in a community-associated methicillin-resistant Staphylococcus aureus epidemic clone, in a case of Infective Endocarditis in Argentina

Annals of Clinical Microbiology and Antimicrobials

Case Report

Alicia Torres¹  Juan P Petiti¹  Ana L Egea²  Claudia Sola²  Vanina Huerta²  Jose L Bocco²  Alejandra Corso³  Ana Vindel⁴  Mario Vilaro⁵  Patricia Gonzalez⁶  Elda G Diaz⁷  Ricardo O Lamberghini⁷  Marcos Ciarlantini⁷  Jose Gonzalez⁷ 

[1] Centro de Microscopía Electrónica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Córdoba, Argentina;Departamento de Bioquímica Clínica, Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET);Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina;Instituto Nacional de Enfermedades Infecciosas Dr. Carlos G. Malbrán, Buenos Aires, Argentina;Laboratorio de Infecciones Nosocomiales, Instituto de Salud Carlos III, Centro Nacional de Microbiología, 28220, Majadahonda, Madrid, Spain;Laboratorio de Microbiología Hospital Privado Centro Médico de Córdoba, Córdoba, Argentina;Laboratorio de Microbiología SUOEM, Córdoba, Argentina;Servicio de Infectología y Microbiología del Hospital Militar de Córdoba, Córdoba, Argentina;

关键词: Vancomycin;    Infective Endocarditis;    Teicoplanin;    Daptomycin;    Epidemic Clone;   

DOI  :  10.1186/1476-0711-10-15

 received in 2011-01-17, accepted in 2011-04-28,  发布年份 2011

来源: Springer

【 摘 要 】

BackgroundCommunity-Associated Methicillin Resistant Staphylococcus aureus (CA-MRSA) has traditionally been related to skin and soft tissue infections in healthy young patients. However, it has now emerged as responsible for severe infections worldwide, for which vancomycin is one of the mainstays of treatment. Infective endocarditis (IE) due to CA-MRSA with heterogeneous vancomycin-intermediate susceptibility-(h-VISA) has been recently reported, associated to an epidemic USA 300 CA-MRSA clone.Case PresentationWe describe the occurrence of h-VISA phenotype in a case of IE caused by a strain belonging to an epidemic CA-MRSA clone, distinct from USA300, for the first time in Argentina. The isolate h-VISA (SaB2) was recovered from a patient with persistent bacteraemia after a 7-day therapy with vancomycin, which evolved to fatal case of IE complicated with brain abscesses. The initial isolate-(SaB1) was fully vancomycin susceptible (VSSA). Although MRSA SaB2 was vancomycin susceptible (≤2 μg/ml) by MIC (agar and broth dilution, E-test and VITEK 2), a slight increase of MIC values between SaB1 and SaB2 isolates was detected by the four MIC methods, particularly for teicoplanin. Moreover, Sab2 was classified as h-VISA by three different screening methods [MHA5T-screening agar, Macromethod-E-test-(MET) and by GRD E-test] and confirmed by population analysis profile-(PAP). In addition, a significant increase in cell-wall thickness was revealed for SaB2 by electron microscopy. Molecular typing showed that both strains, SaB1 and SaB2, belonged to ST5 lineage, carried SCCmec IV, lacked Panton-Valentine leukocidin-(PVL) genes and had indistinguishable PFGE patterns (subtype I2), thereby confirming their isogenic nature. In addition, they were clonally related to the epidemic CA-MRSA clone (pulsotype I) detected in our country.ConclusionsThis report demonstrates the ability of this epidemic CA-MRSA clone, disseminated in some regions of Argentina, to produce severe and rapidly fatal infections such as IE, in addition to its ability to acquire low-level vancomycin resistance; for these reasons, it constitutes a new challenge for the Healthcare System of this country.

【 授权许可】

CC BY   
© Sola et al; licensee BioMed Central Ltd. 2011