Emergence of multidrug-resistant sequence type 45 strains among mecA-positive borderline oxacillin-resistant Staphylococcus aureus causing bacteraemia in a medical centre in Taiwan
Journal
International Journal of Antimicrobial Agents
Journal Volume
52
Journal Issue
1
Pages
70-75
Date Issued
2018
Author(s)
Abstract
Clinical data related to bacteraemia caused by mecA-positive borderline oxacillin-resistant Staphylococcus aureus (BORSA) isolates [minimum inhibitory concentrations (MICs) of 0.5–4 mg/L] are limited. Patients aged ?15 years with bacteraemia due to BORSA who were admitted to the emergency department of a Taiwanese tertiary hospital between January 2001 and December 2015 were evaluated. Clinical characteristics of patients with bacteraemia caused by BORSA, methicillin-susceptible S. aureus and methicillin-resistant S. aureus (MRSA) were compared. MICs of 12 antibiotics were determined by agar dilution. Genetic characteristics of 64 available BORSA isolates were analysed by detection of the SCCmec gene, the mecA promoter region sequence and multilocus sequence typing (MLST). Pulsed-field gel electrophoresis (PFGE) was performed to identify the clonality of the emerging ST isolates. The quinolone resistance genes were analysed for the emerging ciprofloxacin-resistant ST45 clone isolates. Among the 65 BORSA bacteraemic patients, in-hospital mortality was 24.6%, significantly lower than that of MRSA patients (38.5%) (P = 0.03). Underlying conditions were similar between BORSA and MRSA patients, but with less dialysis in the former (P = 0.01). Multivariate analysis revealed that septic shock [odds ratio (OR) = 15.95] and bacteraemia originating from lower respiratory tract infection (OR = 5.78) were two independent risk factors for 30-day mortality. The ST45 clone with high-level ciprofloxacin resistance (MICs of 8–128 mg/L) replaced ST59 as the predominant clone since 2012, although no major clustering was detected. In conclusion, the emerging multidrug-resistant ST45 clone has replaced ST59 as the most common among BORSA isolates. ? 2018 Elsevier B.V. and International Society of Chemotherapy
SDGs
Other Subjects
ciprofloxacin; oxacillin; penicillin binding protein 2a; quinoline derived antiinfective agent; bacterial protein; DNA topoisomerase (ATP hydrolysing); mecA protein, Staphylococcus aureus; oxacillin; penicillin binding protein; adolescent; adult; agar dilution; aged; antibiotic resistance; Article; bacterial gene; bacterial strain; bacterium isolate; clonal variation; cohort analysis; controlled study; emergency ward; female; genetic resistance; genetic trait; hospital admission; hospital mortality; human; human cell; lower respiratory tract infection; major clinical study; male; mecA gene; methicillin resistant Staphylococcus aureus; methicillin susceptible Staphylococcus aureus; middle aged; minimum inhibitory concentration; mortality rate; mortality risk; multidrug resistance; multilocus sequence typing; nonhuman; observational study; priority journal; promoter region; pulsed field gel electrophoresis; retrospective study; septic shock; staphylococcal bacteremia; Staphylococcus aureus; Taiwan; tertiary care center; bacteremia; drug effect; genetics; isolation and purification; metabolism; microbiology; mortality; multidrug resistance; mutation; pathogenicity; Staphylococcus aureus; Staphylococcus infection; very elderly; Aged; Aged, 80 and over; Bacteremia; Bacterial Proteins; DNA Gyrase; Drug Resistance, Multiple, Bacterial; Female; Humans; Male; Methicillin-Resistant Staphylococcus aureus; Middle Aged; Mutation; Oxacillin; Penicillin-Binding Proteins; Retrospective Studies; Staphylococcal Infections; Staphylococcus aureus; Taiwan; Tertiary Care Centers
Type
journal article