Bacteriological Study of Coagulase-Positive and Coagulase-Negative Staphylococci in Relation to Methicillin Sensitivity Testing

Abstract

BACKGROUND Staphylococcus aureus has long been recognised as an important pathogen in human disease. Staphylococci infection occurs regularly in hospitalised patients and has serious consequences despite antibiotic therapy. Shortly after introduction of methicillin after clinical use Methicillin-Resistant Staphylococcus Aureus (MRSA) were identified in many countries and become one of the most common causes of nosocomial infections. The aim of the study is to know the methicillin sensitivity of both coagulase-negative and coagulase-positive staphylococci isolated from various samples. MATERIALS AND METHODS 100 strains of staphylococci both coagulase positive and coagulase negative were isolated in the Department of Microbiology from various clinical samples. They were confirmed by morphology, staining methods and by using standard bacteriological procedures and biochemical reactions. Antibiotic susceptibility testing was performed by Kirby Bauer disc diffusion test. RESULTS Predominant species from pus were S. epidermidis (42.42%) and from sputum S. haemolyticus (31.81%) from blood S. haemolyticus (53.33%). 53% of strains produced beta-lactamase. Majority 47.22% by S. epidermidis from pus followed by S. haemolyticus 23.33% from pus. Beta-lactamase production was least from throat swab (5.55%). Out of 32 coagulase-positive staphylococci tested to methicillin 15 (46.87%) were found to be sensitive, 17 (53.13%) were found to be resistant. Out of 68 coagulase-negative staphylococci tested, 13 (19.11%) were found to sensitive and 55 (80.88%) were found to be resistant. 72% of strains were sensitive to novobiocin and 28% resistant to novobiocin. 43% showed drug resistance to 2 drugs. 14% to 3 drugs and 5 drugs. 6% of staphylococci sensitive to all the 10 drugs. CONCLUSION MRSA is a type of bacteria that is resistant to a number of widely used antibiotics. This means MRSA infections can be more difficult to treat than other bacterial infections. In recent years, rates of MRSA have fallen because of increased awareness of the infection by both medical staff and the public. However, MRSA still places a considerable strain on healthcare services. Some people who need to be admitted to hospital will have MRSA screening beforehand, but there are also some things you can do yourself to reduce your risk of becoming infected. These include:  Washing your hands frequently-especially after using the toilet and before and after eating.  Following any advice you are given about wound care and devices that could lead to infection (such as urinary catheters).  Reporting any unclean toilet or bathroom facilities to staff-don't be afraid to talk to staff if you're concerned about hygiene. If you're visiting someone in hospital, you can reduce the chance of spreading MRSA by cleaning your hands before and after entering the ward. You should also use hand wipes or hand gel before touching the person you're visiting.