Vancomycin heteroresistance in Staphylococcus haemolyticus: elusive phenotype

Yamuna Devi Bathavatchalam; Dhanalakshmi Solaimalai; Anushree Amladi; Hariharan Triplicane Dwarakanathan; Shalini Anandan; Balaji Veeraraghavan

doi:10.2144/fsoa-2020-0179

Vancomycin heteroresistance in Staphylococcus haemolyticus: elusive phenotype

Future Sci OA. 2021 Apr 9;7(7):FSO710. doi: 10.2144/fsoa-2020-0179. eCollection 2021 Aug.

Authors

Yamuna Devi Bathavatchalam¹, Dhanalakshmi Solaimalai¹, Anushree Amladi¹, Hariharan Triplicane Dwarakanathan², Shalini Anandan¹, Balaji Veeraraghavan¹

Affiliations

¹ Department of Clinical Microbiology, Christian Medical College, Vellore, India.
² Department of Orthopaedics, Christian Medical College, Vellore, India.

Abstract

Aim: To determine the presence of vancomycin heteroresistance in Staphylococcus haemolyticus.

Materials & methods: A total of 48 rifampicin-resistant S. haemolyticus isolates from bloodstream infections were included. Vancomycin heteroresistance was determined using the population analysis profile-area under curve (PAP-AUC) method. All the isolates were screened for the presence of mecA gene, mutations in the rpoB gene, staphylococcal cassette chromosome mec and multilocus sequence types.

Results: Fifteen isolates were identified as heteroresistant vancomycin-intermediate S. haemolyticus using PAP-AUC method. Dual rpoB mutations (D471E and I527M) contributed for the rifampicin resistance. The sequence types of heteroresistant vancomycin-intermediate S. haemolyticus were highly diverse.

Conclusion: These findings illustrate the potential of S. haemolyticus to develop heteroresistance, which emphasizes the need for routine surveillance of S. haemolyticus isolated from intensive care units for infection control practices.

Keywords: antibiotics; drug development; drug resistance; epidemiology; infectious disease.