Puneet Bhatt1, Kundan Tandel2, Alina Singh3, M Kumar4, Naveen Grover5, A K Sahni6. 1. Graded Specialist (Microbiology), Command Hospital (Southern Command), Pune 411040, India. 2. Graded Specialist (Microbiology), Defence Research & Development Establishment, Gwalior, India. 3. Assistant Professor, Nepalese Army Institute of Health Sciences, Nepal. 4. Professor, Dept of Microbiology, Armed Forces Medical College, Pune 411040, India. 5. Professor & Head, Dept of Microbiology, Armed Forces Medical College, Pune 411040, India. 6. Commandant, 174 Military Hospital, C/o 56 APO, India.
Abstract
BACKGROUND: Methicillin-resistant Coagulase-negative Staphylococci (MR-CoNS) have emerged as an important cause of nosocomial infections especially in patients with prosthetic devices and implants. This study was conducted with an aim to determine the prevalence of methicillin resistance among CoNS isolates at a tertiary care center by both phenotypic and genotypic methods. METHODS: This cross sectional study was carried out from September 2011 to February 2014 in which 150 non-repetitive clinical isolates of CoNS were identified at the species level by conventional phenotypic methods. Cefoxitin disk (30 μg) diffusion testing was used to determine methicillin resistance and confirmed by detection of mecA gene by polymerase chain reaction (PCR). RESULTS: Out of 150 CoNS isolates, 51 were methicillin resistant by cefoxitin disk diffusion method. Out of these 51 isolates, mecA gene was detected only in 45 isolates. Moreover, mecA gene was also detected in 4 isolates, which were cefoxitin sensitive. Thus, the prevalence of methicillin resistance among CoNS was found to be 32.7% by PCR. CONCLUSION: The prevalence of methicillin resistance among Coagulase-negative Staphylococci (CoNS) was 32.7% by PCR detection of mecA gene. The sensitivity and specificity of cefoxitin disk diffusion method against mecA gene detection by PCR were found to be more than 90%. It can be concluded from this study that cefoxitin disk diffusion test can be used as a useful screening method to detect methicillin resistance among CoNS isolates. However, detection of mecA gene by PCR remains a more accurate method of detecting methicillin resistance among CoNS.
BACKGROUND:Methicillin-resistant Coagulase-negative Staphylococci (MR-CoNS) have emerged as an important cause of nosocomial infections especially in patients with prosthetic devices and implants. This study was conducted with an aim to determine the prevalence of methicillin resistance among CoNS isolates at a tertiary care center by both phenotypic and genotypic methods. METHODS: This cross sectional study was carried out from September 2011 to February 2014 in which 150 non-repetitive clinical isolates of CoNS were identified at the species level by conventional phenotypic methods. Cefoxitin disk (30 μg) diffusion testing was used to determine methicillin resistance and confirmed by detection of mecA gene by polymerase chain reaction (PCR). RESULTS: Out of 150 CoNS isolates, 51 were methicillin resistant by cefoxitin disk diffusion method. Out of these 51 isolates, mecA gene was detected only in 45 isolates. Moreover, mecA gene was also detected in 4 isolates, which were cefoxitin sensitive. Thus, the prevalence of methicillin resistance among CoNS was found to be 32.7% by PCR. CONCLUSION: The prevalence of methicillin resistance among Coagulase-negative Staphylococci (CoNS) was 32.7% by PCR detection of mecA gene. The sensitivity and specificity of cefoxitin disk diffusion method against mecA gene detection by PCR were found to be more than 90%. It can be concluded from this study that cefoxitin disk diffusion test can be used as a useful screening method to detect methicillin resistance among CoNS isolates. However, detection of mecA gene by PCR remains a more accurate method of detecting methicillin resistance among CoNS.
Authors: F J Schmitz; A C Fluit; M Gondolf; R Beyrau; E Lindenlauf; J Verhoef; H P Heinz; M E Jones Journal: J Antimicrob Chemother Date: 1999-02 Impact factor: 5.790