Staphylococcus aureus bacteremia in an Indian tertiary care hospital: observational study on clinical epidemiology, resistance characteristics, and carriage of the Panton-Valentine leukocidin gene

Abstract

Objectives: To analyze the epidemiology and laboratory characteristics of Staphylococcus aureus bacteremia (SAB) in an Indian tertiary care hospital.

Methods: We collected clinical, epidemiological, and laboratory data of all cases of SAB during August 2010 through July 2011. All isolates were tested for the Panton-Valentine leukocidin (PVL) gene.

Results: Eighteen percent of all blood stream infections (BSIs) were attributable to S. aureus. Among a total of 70 cases of SAB, 54% were due to methicillin-resistant S. aureus (MRSA) and 46% to methicillin-susceptible S. aureus (MSSA). Seventy-four percent of the cases had community-acquired (CA) SAB, among whom 69% had been hospitalized previously. Skin and soft tissue infections (SSTI) (30%) and respiratory infections (24%) were the common sources of bacteremia. The overall case fatality rate was 27%, and a similar percentage (23%) of patients discontinued therapy due to a poor medical outcome. The PVL gene was detected in 16% of S. aureus isolates, predominantly in CA-S. aureus (82%). SSTIs and pneumonia were the common sources of bacteremia in 45% of patients infected with a PVL-positive strain.

Conclusions: S. aureus is a significant cause of BSI with a case fatality rate comparable to those of other developing nations. The upsurge in MRSA rates is alarming in our setup. Antibiotic stewardship and strict control of antibiotic use must be implemented by health care professionals to curb the increasing trend in MRSA BSIs.

Keywords: Bacteremia; MRSA; PVL gene; Staphylococcus aureus.