Underdiagnosis of Borderline oxacillin-resistant Staphylococcus aureus (BORSA) - Case series.
Malays J Pathol
; 46(1): 95-102, 2024 Apr.
Article
em En
| MEDLINE
| ID: mdl-38682849
ABSTRACT
Borderline oxacillin-resistant Staphylococcus aureus (BORSA) are mecA-negative strains with oxacillin minimum inhibitor concentration (MIC) close to the resistance breakpoint of ≥ 4µg/mL. Instead of producing penicillin-binding protein with low affinity to methicillin (oxacillin) mediated by mecA gene as in methicillin-resistant S. aureus (MRSA), BORSA strains are characterised by the hyperproduction of ß-lactamase enzymes, thus able to break down methicillin. Common laboratory methods to detect MRSA such as cefoxitin disk diffusion alone may fail to detect methicillin resistance due to BORSA. We report five cases of BORSA blood-stream infections in a university teaching hospital. All isolates were found to be susceptible to cefoxitin using disk diffusion, resistant to oxacillin using automated MIC method, and did not harbour mecA gene. All patients were suscessfully treated with anti-MRSA antibiotics, and removal of primary sources were done if identified. A more cost-effective method for screening and diagnosis of BORSA is needed in addition to cefoxitin disk diffusion test, in order to monitor the spread, and to enable routine detection and treatment of this pathogen.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Oxacilina
/
Infecções Estafilocócicas
/
Antibacterianos
Limite:
Humans
Idioma:
En
Ano de publicação:
2024
Tipo de documento:
Article