Vancomycin heteroresistance, and inducible and constitutive clindamycin resistance in staphylococci.

Chatterjee Shiv Sekhar; Karmachrya Rajendra; Madhup Surendra Kumar; Gautam Vikas; Ray Pallab

Volume : VII, Issue : VIII, August - 2018

Vancomycin heteroresistance, and inducible and constitutive clindamycin resistance in staphylococci.

Chatterjee Shiv Sekhar, Karmachrya Rajendra, Madhup Surendra Kumar, Gautam Vikas, Ray Pallab

Abstract :

Vancomycin and clindamycin represent useful options in therapy of staphylococcal infections. High MICs to vancomycin, heteroresistance and inducible clindamycin resistance, often not detected in routine, are valuable in therapeutic decision making for staphylococcal infections.We evaluated clinically significant, non–repetitive197 S. aureus and 67 coagulase negative staphylococci (CoNS) isolatesfor antimicrobial resistance (AMR), methicillin resistance (oxacillin agar screen, cefoxitin disc test, and oxacillin MIC), vancomycin MICs (agar dilution and oth dilution), vancomycinheteroresistance (BHIA–6 method), and constitutive and inducible clindamycinresistance (D–test, 15mm and 25mm).Methicillin resistance was observed in 80 (40.6%) and 31 (46.3%) isolates of S. aureus (MRSA) and CoNS(MRCoNS) respectively. Resistance to erythromycin, clindamycin, aminoglycosides and ciprofloxacin was more common among MRSA than methicillin sensitive S. aureus (MSSA) (P value < 0.001). Intermediate resistance to vancomycin was found in 0%, 21.3%, and 1.5% of MSSA, MRSA and CoNS isolates. Vancomycinheteroresistance was found in 0%, 16.3%, and 4.5% of MSSA, MRSA and CoNS isolates. Inducible clindamycin resistance was found in 12%, 22.5%, and 9% of MSSA, MRSA and CoNS isolates. Detection of rampant AMR in staphylococci by various supplementary methods is of importance.