Authors: Frances Adlam, Future Science Group
Researchers from JMI laboratories (IA, USA) report on findings from a study that discovered the susceptibility trends of Staphylococcus aureus to antibiotics in US hospitals, increased over time. These surprising results were recently presented at the ASM Microbe conference (1–5 June, LA, USA).
The team of researchers tested 19, 036 clinical isolates from 42 medical centers across the US from 2009–2015. The susceptibility of S. aureus to antibiotics was tested using gold standard, broth microdilution methods.
The results demonstrated that the rate of S. aureus resistance to oxacillin (MRSA) decreased from 47.2% in 2009 to 43.6% in 2015. Resistance to levofloxacin, clindamycin and erythromycin also decreased over time with ceftaroline persisting as an effective antibiotic against methicillin-resistant S. aureus (97.2% susceptible) and methicillin-susceptible S. aureus (100.0% susceptible).
Importantly, S. aureus resistance to daptomycin, linezolid, vancomycin and tigecycline was extremely rare with little evidence of increasing.
“The prevalence of the main S. aureus clone causing community-acquired and healthcare-associated infections in many parts of the US seems to be decreasing in some areas,” commented Helio S. Sader, Senior Director, Microbiology & Surveillance at JMI Laboratories. “A prevalence decrease may change the antimicrobial resistance profiles of S. aureus, emphasizing the importance of monitoring this organism through large resistance surveillance programs.”