Genetic characterisation of clinical isolates of Staphylococci

Abstract

Staphylococcus aureus and coagulase negative Staphylococci CONS cause infections in humans leading to high morbidity and mortality Treatment strategies for infections caused by Staphylococci have become more complex due to their rapid acquisition of resistance genes Though a few studies have been done to detect the virulence genes in Staphylococcus aureus their association with clinical spectrum and outcome of infections have been seldom studied in India The distribution of virulence genes among CONS and the emerging linezolid resistance in Staphylococcus haemolyticus have been rarely reported from India The present study was undertaken to detect resistance mechanisms of methicillin mupirocin and linezolid resistance characterize common genes encoding for virulence and study their association with clinical outcomes among clinical isolates of Staphylococci in a tertiary care centre The study also aimed to determine the clonal relatedness among selective isolates newline newlineA total 336 clinically significant non repetitive Staphylococci isolates were included in the study The current study revealed high methicillin resistance among CONS when compared to Staphylococcus aureus with SCCmec type I as common among both the phenotypes Novel mutation in the 23s rRNA and cfr gene encoding linezolid resistance was detected in Staphylococcus haemolyticus MupA mediating mupirocin resistance was detected predominantly among CONS The distribution of virulence genes among methicillin susceptible and resistant isolates was similar The virulence genes hlb hla and fnbA were common among Staphylococcus aureus while among CONS the atlE was the most predominant Staphylococcus aureus belonged to ST672 ST72CC8 and ST1CC1 while Staphylococcus haemolyticus belonged to ST1 and ST3 The current study revealed a wide spectrum of virulence genes and variety of clinical presentations Additionally resistance to prophylactic drugs like mupirocin and reserved drugs such as linezolid is alarming highlighting the judicious use of antibiotics newline newline