Detection of heterogeneous vancomycin-intermediate Staphylococcus aureus: A preliminary report from south India

• Published in: Indian journal of medical research (New Delhi, India : 1994) Vol. 150; no. 2; pp. 194 - 198
• Main Authors: Amberpet, Rajesh, Sistla, Sujatha, Sugumar, Madhan, Nagasundaram, Niveditha, Manoharan, Meerabai, Parija, Subhash
• Format: Journal Article
• Language: English
• Published: India Wolters Kluwer India Pvt. Ltd 01.08.2019; Medknow Publications and Media Pvt. Ltd; Medknow Publications & Media Pvt. Ltd; Wolters Kluwer - Medknow
• Subjects: Anti-Bacterial Agents - adverse effects; Anti-Bacterial Agents - therapeutic use; Antibacterial agents; Antibiotics; Area Under Curve; Bacterial Proteins - genetics; Biochemical assays; Brain research; Culture Media - chemistry; Culture Media - pharmacology; Genes; Humans; India - epidemiology; Interspersed Repetitive Sequences - genetics; Laboratories; Medical education; Methicillin; Methicillin-Resistant Staphylococcus aureus - drug effects; Methicillin-Resistant Staphylococcus aureus - genetics; Methicillin-Resistant Staphylococcus aureus - pathogenicity; Methods; Microbial drug resistance; Microbial Sensitivity Tests; Original; Penicillin-Binding Proteins - genetics; Physiological aspects; Polymerase chain reaction; Staphylococcal Infections - drug therapy; Staphylococcal Infections - genetics; Staphylococcal Infections - microbiology; Staphylococcus aureus; Staphylococcus infections; Studies; Transposons; Vancomycin; Vancomycin - adverse effects; Vancomycin - therapeutic use; Vancomycin Resistance - genetics; India; United States > US; Japan; BHIV4; SCC mec type; mecA; hVISA; methicillin-resistant Staphylococcus aureus; vancomycin; PAP method
• ISSN: 0971-5916
• DOI: 10.4103/ijmr.IJMR_1976_17

Background & objectives: Although there are reports of heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) across the globe, there is a lack of reliable data on hVISA in India. The present study was undertaken to determine the rate of hVISA among the methicillin-resistant Staphylococcus aureus (MRSA) isolates, and to compare the brain heart infusion agar with vancomycin 4 μg/ml (BHIV4) method with population analysis profile-area under the curve (PAP-AUC) method for the detection of hVISA and to study the distribution of mobile genetic element that carries methicillin-resistance gene SCCmec (Staphylococcal cassette chromosome mec) types among these isolates. Methods: BHIV4 and PAP-AUC methods were employed to detect hVISA among 500 clinical isolates of MRSA. SCCmec typing of these isolates was performed by multiplex polymerase chain reaction. The clinical presentation, treatment with vancomycin and outcome was documented for patients with hVISA. Results: The rate of hVISA was 12.4 per cent by PAP-AUC method. Sensitivity, specificity, PPV, NPV and kappa agreement of BHIV4 with PAP-AUC was 58.06, 93.15, 54.55, 94.01 per cent and 0.498, respectively. The isolation of hVISA was significantly (P<0.01) higher in patients admitted to intensive care units and wards than in patients attending the outpatient departments. Only 38 per cent of the patients received vancomycin as therapy. Majority of the hVISA isolates carried SCCmec type V or IV. Interpretation & conclusions: The rate of hVISA isolation in our study was 12.4 per cent. The sensitivity of the BHIV4 screening test was low, and was in moderate agreement with PAP-AUC test. SCCmec type V was the predominant type seen in half of the isolates. More studies need to be done in different parts of the country on a large number of isolates to confirm our findings.