METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS (MRSA) ISOLATES IN ILORIN, NIGERIA

SS Taiwo, BA Onile, AA Akanbi II

 

Abstract

Nosocomial infections caused by methicillin-resistant strains of Staphylococcus aureus often pose therapeutic dilemma to the clinicians because of the multi resistant nature of these strains of Staphylococcus aureus. Outbreaks of both nosocomial and community acquired infections are also frequent and difficult to control. This study determined the prevalence and antimicrobial susceptibility pattern of methicillin-resistant Staphylococcus aureus (MRSA) at the University of Ilorin Teaching Hospital, between January and December 2001. The methicillin disc diffusion method for the detection of methicillin resistance and the Kirby-Bauer disc diffusion for antibiotic susceptibility tests, were used. The MRSA prevalence rate was 34.7% (51/147) of all Staphylococcus aureus isolates. Forty-five isolates were associated with infections and 6 were colonizing strains. Thirty-six (70.6%) were hospital (nosocomial) acquired while 15 (29.4%) were community-acquired. Forty-eight patients have received antibiotics previously including 30 who had received multiple antibiotics. Skin and soft tissues were sites of infections in 36 cases and surgical, emergency and intensive care units accounted for 31 isolates. All MRSA isolates were resistant to more than two antibiotics but remained largely susceptible to third generation cephalosporins, macrolides and quinolones and all were sensitive to vancomycin. We recommend the use of third generation cephalosporins and quinolones where indicated, in the treatment of serious MRSA infections in this environment. Control of the spread of MRSA in this hospital must include reinforcement of appropriate use of antibiotics, hand washing and laboratory surveillance for MRSA, particularly in the surgical wards and intensive care units, in order to identify sources of outbreaks.

Key Words: Methicillin-resistant, Staphylococcus aureus, Ilorin.

Afr. J. Clin. Exper. Microbiol. 2004; 5(2): 189 – 197.

METHICILLIN RESISTANCE IN STAPHYLOCOCCAL ISOLATES FROM CLINICAL AND ASYMPTOMATIC BACTERIURIA SPECIMENS: IMPLICATIONS FOR INFECTION CONTROL

B.O. Olayinka, A.T. Olayinka

 

Abstract

The study assessed the importance of Staphylococcus aureus as a urinary pathogen and the incidence of multidrug resistant (MDR), methicillin-resistant Staphylococcus aureus (MRSA). A total of 86 staphylococcal isolates made up of 50 clinical isolates from urine samples submitted to the Medical Microbiology Laboratory of Ahmadu Bello University Teaching Hospital and 36 asymptomatic bacteriuria isolates from urine samples of ‘healthy’ volunteers within the university community were tested for their susceptibility to various antibiotics and production of b-lactamase enzyme. A total of 27 isolates (31.4%) were methicillin resistant, with 12(44.4%) being methicillin resistant coagulase-negative staphylococci (MRCNS). Majority of the isolates tested were resistant to the cheap, readily available broad-spectrum antibiotics; ampicillin, amoxicillin, chloramphenicol, tetracycline and penicillin G. All the isolates were resistant to three or more of the antimicrobial agents tested. A total of 14/50 (28%) of the clinical isolates and 17/36 (47.2%) of the ‘community’ isolates from healthy volunteers were resistant to 7 or more of the antimicrobial agents tested. Analysis of the multiple antibiotic resistance (MAR) index of isolates and the production of b-lactamase enzyme showed that 56 isolates representing 65.1% of the total number tested had an MAR index of 0.5 and above indicating that they probably originated from an environment where antibiotics are frequently used. The implication of these findings for instituting effective control measures aimed at reducing the pool of antibiotic-resistant organisms is discussed.

Key words: Methicillin-resistant, staphylococcus aureus, asymptomatic bacteriuria, infection control
(Af J Clinical & Exp Microbiology: 2003 4(2): 79-90)