Phenotypic Expression of erm Gene Among Staphylococcus aureus

Abstract

Introduction: The increasing frequency of MRSA infections and rapidly changing patterns in antimicrobial resistance, led to renewed interest in the use of macrolide lincosamide-streptogramin B (MLSB) antibiotics to treat such infections. Aim: To assess the prevalence of phenotypic expression of inducible resistance for clindamycin due to expression of erm genes, in clinical isolates of Methicillin resistant Staphylococcus aureus from various clinical samples using modified D test. Materials and Methods: A total of 101 Methicillin resistant Staphylococcus aureus (MRSA) strains were included for induction tests which utilize closely approximated erythromycin, clindamycin and azithromycin discs (modified D test); the flattening or indentation of the clindamycin zone of inhibition adjacent to the erythromycin and / or azithromycin disk indicates inducible MLSB (macrolide lincosamide-streptogramin B) resistance. Results: Among the 101 clinical isolates, 37 (36.63%) isolates shows D test positive using Erythromycin, Clindamycin and Azithromycin combination. Inducible resistance to clindamycin using azithromycin was found in 5.94% isolates which was the major achievement of the study, which will be confirmed by genotyping in future. Conclusion: D-test should be performed on all MRSA isolates, to avoid erroneous reporting resulting in treatment failure, a partial modification in the D test can be made using azithromycin as it was helpful in our study, must be confirmed using genotyping.

Detection of inducible clindamycin resistance in Staphylococcus aureus from various samples in a tertiary care hospital

“…In the present study, aureus that is in accordance with this study. 1,[28][29][30][31] The lowest prevalence was reported 3.5% by Kalpana D, Mamta C, Vilas T at Nagpur district and highest resistance was reported 90% by Dizbay M, Gunal O, Ozkan Y et al 32,33 However Deshmukh et al, reported 14.8% inducible clindamycin resistance. 19,[34][35][36] In this study, Overall prevalence of constitutive resistant isolates was 28%, Gurdal Yilmaz 17,18,29,31 Angel MR, Balaji V, Prakash J et al, didn't report any constitutive resistance in their study and Saderi H, Emadi B and Owlia P reported about 93% constitutive clindamycin resistance in their study.…”

Inducible Clindamycin resistance and MRSA amongst Staphylococcus aureus isolates: A phenotypic detection

“…Day by day treatment spectrum becoming narrow as increasing resistance to the Staphylococcal infection as this led to renewed interest in the use of Clindamycin. 2 It is useful drug in the treatment of Methicilin sensitive and Methicillin resistant Staphylococcus aureus infection. 14 tro susceptibility to Clindamycin in the case of inducible MLSB resistance.…”

“…S. aureus is causing various infections that ranges from minor skin and tissue infection to life threatening consequences such as endocarditis, pneumonia and septicaemia. 1,2 There is an increased cases of Methicillin resistant S. aureus (MRSA) in recent years and it varies with geographical location and bacterial species. 3,4 For MRSA infection Vancomycin considered as drug of choice even though vancomycin usage is associated with considerable side effects and all of above more frequent use of this drug leads to emergence of Vancomycin resistance strain.…”

“…In this phenotype clindamycin therapy can lead to therapeutic failure. 2,[9][10][11][12] Another mechanism of resistance is antibiotic efflux through msrA genes shows resistance to macrolides and streptogramin B only. In such cases Staphylococcal isolates appear erythromycin resistant and clindamycin sensitive both in vitro and in vivo.…”