Staph epidermidis is now a major cause of nosocomial infections

Staphylococcus epidermidis is a very common commensal bacterium of skin and therefore is generally ignored. However, new research published in the journal Nature Communications says that this seemingly innocent bacterium is now a major cause of post-surgical, often life-threatening, infections; moreover, it is becoming antibiotic resistant.

Researchers from the Milner Centre for Evolution at the University of Bath warn that the threat posed by Staph epidermidis should be taken more seriously and extra caution should be taken for those at higher risk of infection who are due to undergo surgery.

Samples from patients who developed infections following hip or knee joint replacement and fracture fixation surgeries were compared with swab samples from the skin of healthy volunteers. The genetic variation in the whole genomes of bacteria found in samples from diseased and healthy individuals were then compared. A set of 61 genes containing infection-associated genetic elements (k-mers) that correlate with in vitro variation in known pathogenicity traits (biofilm formation, cell toxicity, interleukin-8 production, methicillin resistance) were identified in the disease-causing bacteria that were not present in most of the healthy samples.

These genes helped the bacteria to grow in the bloodstream, avoid the host’s immune response, make the cell surface sticky so that the organisms could form biofilms and make them resistant to antibiotics. Some of the healthy individuals were found to be carrying the more deadly form of the bacteria without knowing it.

Researchers hope that the identification of disease-associated genes may help to separate harmless skin Staph epidermidis isolates from disease-causing genotypes preoperatively in the clinical laboratory.

(Source: University of Bath, Nov. 28, 2018)

Dr KK Aggarwal

Padma Shri Awardee

President Elect Confederation of Medical Associations in Asia and Oceania   (CMAAO)

Group Editor-in-Chief IJCP Publications

President Heart Care Foundation of India

Immediate Past National President IMA