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Cefazolin high-inoculum effect in methicillin-susceptible Staphylococcus aureus from South American hospitals.


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Información de la publicación
Tipo de publicación

Científica

Tipología

Investigación y estudios

Medio de publicación

Impreso: Revista de divulgación científica

Resumen

 OBJECTIVES:

Clinical failures with cefazolin have been described in high-inoculum infections caused by methicillin-susceptible Staphylococcus aureus (MSSA) producing type A β-lactamase. We investigated the prevalence of the cefazolin inoculum effect (InE) in MSSA from South American hospitals, since cefazolin is used routinely against MSSA due to concerns about the in vivo efficacy of isoxazolyl penicillins.

METHODS:

MSSA isolates were recovered from bloodstream (n = 296) and osteomyelitis (n = 68) infections in two different multicentre surveillance studies performed in 2001-02 and 2006-08 in South American hospitals. We determined standard-inoculum (105cfu/mL) and high-inoculum (107 cfu/mL) cefazolin MICs. PFGE was performed on all isolates that exhibited a cefazolin InE. Multilocus sequence typing (MLST) and sequencing of part of blaZ were performed on representative isolates.

RESULTS:

The overall prevalence of the cefazolin InE was 36% (131 isolates). A high proportion (50%) of MSSA isolates recovered from osteomyelitis infections exhibited the InE, whereas it was observed in 33% of MSSA recovered from bloodstream infections. Interestingly, Ecuador had the highest prevalence of the InE (45%). Strikingly, 63% of MSSA isolates recovered from osteomyelitis infections in Colombia exhibited the InE. MLST revealed that MSSA isolates exhibiting the InE belonged to diverse genetic backgrounds, including ST5, ST8, ST30 and ST45, which correlated with the prevalent methicillin-resistant S. aureus clones circulating in South America. Types A (66%) and C (31%) were the most prevalent β-lactamases.

CONCLUSIONS:

Our results show a high prevalence of the cefazolin InE associated with type A β-lactamase in MSSA isolates from Colombia and Ecuador, suggesting that treatment of deep-seated infections with cefazolin in those countries may be compromised.

Autores

Rincón S, Reyes J, Carvajal LP, Rojas N, Cortés F, Panesso D, Guzmán M, Zurita J, Adachi JA, Murray BE, Nannini EC, Arias CA.

Registro ISSN

1460-2091 (Electronic)

SNIES Área

Immunology and Microbiology

SNIES Categoría

Microbiology

Fecha de publicación 21 de junio de 2013
Fecha de aceptación 24 de mayo de 2013
Medio indexado (nombre)

The Journal of Antimicrobial Chemotherapy

Bases de datos donde está referenciada

PubMed

English information
Title

Cefazolin high-inoculum effect in methicillin-susceptible Staphylococcus aureus from South American hospitals

Abstract

OBJECTIVES:
Clinical failures with cefazolin have been described in high-inoculum infections caused by methicillin-susceptible Staphylococcus aureus (MSSA) producing type A β-lactamase. We investigated the prevalence of the cefazolin inoculum effect (InE) in MSSA from South American hospitals, since cefazolin is used routinely against MSSA due to concerns about the in vivo efficacy of isoxazolyl penicillins.
METHODS:
MSSA isolates were recovered from bloodstream (n = 296) and osteomyelitis (n = 68) infections in two different multicentre surveillance studies performed in 2001-02 and 2006-08 in South American hospitals. We determined standard-inoculum (105cfu/mL) and high-inoculum (107 cfu/mL) cefazolin MICs. PFGE was performed on all isolates that exhibited a cefazolin InE. Multilocus sequence typing (MLST) and sequencing of part of blaZ were performed on representative isolates.
RESULTS:
The overall prevalence of the cefazolin InE was 36% (131 isolates). A high proportion (50%) of MSSA isolates recovered from osteomyelitis infections exhibited the InE, whereas it was observed in 33% of MSSA recovered from bloodstream infections. Interestingly, Ecuador had the highest prevalence of the InE (45%). Strikingly, 63% of MSSA isolates recovered from osteomyelitis infections in Colombia exhibited the InE. MLST revealed that MSSA isolates exhibiting the InE belonged to diverse genetic backgrounds, including ST5, ST8, ST30 and ST45, which correlated with the prevalent methicillin-resistant S. aureus clones circulating in South America. Types A (66%) and C (31%) were the most prevalent β-lactamases.
CONCLUSIONS:
Our results show a high prevalence of the cefazolin InE associated with type A β-lactamase in MSSA isolates from Colombia and Ecuador, suggesting that treatment of deep-seated infections with cefazolin in those countries may be compromised.

Keywords

inoculum effect, bloodstream infections, osteomyelitis, cefazolin

Información de apoyo a la difusión
Documentos J._Antimicrob._Chemother.-2013-Rincón-jac-dkt254.pdf

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