Resistance mechanism and clinical feature of linezolid-resistant Staphylococcus capitis isolated from blood samples / 中国感染与化疗杂志

Objective To understand the resistance mechanism and clinical feature of linezolid-resistant S.capitis isolated from blood samples.Methods Antimicrobial susceptibility testing was carried out to determine the susceptibility of clinical strains.PCR and sequencing analysis were used to analyze cfr gene and 23S rRNA mutation,which were associated with linezolid resistance.Patterns of pulsed-field gel electrophoresis (PFGE) were analyzed in combination with clinical data to understand the clinical feature of S.capitis strains.Results Five linezolid-resistant S.capitis strains were isolated from blood samples of 3 patients.These strains were resistant not only to linezolid,but also to most of the commonly used antimicrobial agents except glycopeptides,rifampin,and trimethoprim-sulfamethoxazole.Mutation was identified in 23S rRNA genes of all the five strains and cfr gene was found in four of the five strains.PFGE typing showed the same type,which supported the homology of the 5 strains.Three patients had deep vein indwelling catheter and two of them were treated with linezolid.Conclusions Linezolid-resistant S.capitis isolates showed the phenotype of resistance to multiple antimicrobial agents.Linezolid resistance may be mediated by cfr gene and 23S rRNA mutations in S.capitis.Long-term use of deep vein indwelling catheter and linezolid treatment may increase the risk of linezolid-resistant S.capitis infection.

Evaluation of resistance of commonly used antibiotics on clinical case of Staphylococcus capitis from Assir region, Saudi Arabia.

Staphylococcus capitis is a coagulase-negative species (CoNS) of Staphylococcus. It causes antimicrobial resistance for nosocomial infections as well as for community-acquired infections. This case report involves a 51-year-old, married Saudi patient. He got admitted to the male medical ward of Aseer Central Hospital, with severe chest infection. Clinical examination, X-ray, and laboratory investigations were performed which involved bactech, culture media, antibiotic sensitivity test using disk diffusion [minimum inhibitory concentration (MIC)] and molecular [polymerase chain reaction (PCR)] for detection of CoNS of Staphylococcus species and detection of the mecA gene. Laboratory data were recorded in special formats and analyzed by statistical computer program (SPSS). Results showed the resistance of isolated S. capitis to many commonly used antibiotics.