Prevalence And Current Antibiogram Of Staphylococci Isolated From Various Clinical Specimens In A Tertiary Care Hospital In Pondicherry
S Kumar, N Joseph, J Easow, S Umadevi, G Kumari, S Rangaraj, S Pramodhini, R Singh
antibiotic susceptibility, coagulase negative, methicillin resistance, prevalence, staphylococci
S Kumar, N Joseph, J Easow, S Umadevi, G Kumari, S Rangaraj, S Pramodhini, R Singh. Prevalence And Current Antibiogram Of Staphylococci Isolated From Various Clinical Specimens In A Tertiary Care Hospital In Pondicherry. The Internet Journal of Microbiology. 2012 Volume 10 Number 1.
Material and Methods
This cross-sectional study was conducted in the Department of Microbiology of Mahatma Gandhi Medical College and Research Institute, a 750-bedded tertiary care super-specialty hospital with teaching facility, located in Pondicherry, India. It serves as a referral centre for tertiary specialist care for a catchment population of approximately 10 lakh people from Pondicherry and adjoining areas.
Bacterial identification and antibiotic susceptibility testing
The study comprised of 550 coagulase-positive and coagulase-negative staphylococci isolated from various clinical specimens (pus, sputum, tracheal aspirate, body fluids and high vaginal swab). These isolates were subjected to methicillin resistance screening using conventional microbiological methods. The clinical specimens were inoculated on 5% sheep blood agar, Mac Conkey agar and incubated at 37°C aerobically for 24h.
Detection of methicillin resistance
All the confirmed
Data entry and analysis were done using SPSS for Windows Version SPSS 16.0 (SPSS Inc, Chicago, IL, USA). Percentages were calculated for categorical variables. The Chi-square test or Fisher’s exact test was used to compare two groups. All
The distribution pattern of 550 Staphylococcal isolates from various samples and wards is shown in Table 1. Most of the Staphylococcal isolates were from patients admitted in surgery wards, followed by orthopedics and obstetrics and gynecology. Methicillin resistance was seen in 17.2% (59/ 343) isolates of
Of the 550 isolates of
MS-CoNS – methicillin sensitive coagulase negative staphylococci, MR-CoNS – methicillin resistant coagulase negative staphylococci, MSSA – methicillin sensitive
The variation in MRSA prevalence might be because of several factors like efficacy of infection control practices, healthcare facilities and antibiotic usage that vary from hospital to hospital.
We observed that the many of the MRSA isolates, besides their resistance to β-lactam drugs, showed resistance to co-trimoxazole, ciprofloxacin, erythromycin, gentamicin and tetracycline. Researchers in other part of the globe also observed that many of these MRSA isolates were becoming multidrug resistant and were susceptible only to glycopeptide antibiotics such as vancomycin. The mobile genetic element termed staphylococcal cassette chromosome
In our study the MR-CoNS which showed resistance to oxacillin and cefoxitin accounted for 23.2% of CoNS, which is similar to that reported from North India by Uma et al,15 according to which 25% of all CoNS isolated were methicillin resistant. In a similar study from Aligarh, India, it was shown that 22.5% of coagulase-negative staphylococcal isolates were resistant to methicillin. The Methicillin resistance observed in CoNS is also mediated by the
We conclude that MRSA and MR-CoNS are prevalent in our hospital. Our study shows sensitivity of MRSA to vancomycin is 100% which further emphasizes that it is still the drug of choice for MRSA infections. In our study about 78% of the MRSA were susceptible to clindamycin. Therefore, clindamycin has an important role in the management of MRSA infections, especially, the community-acquired. The resistance of MRSA was very high for co-trimoxazole (88.1%) and ciprofloxacin (81.4%). The MR-CoNS showed very high resistance for co-trimoxazole (79.2%) and erythromycin (72.9%). We recommend that frequent monitoring of susceptibility patterns of MRSA and MRCONS and the formulation of a definite antibiotic policy may be helpful in decreasing the incidence of MRSA and MRCONS infection.