Prevalence of Methicillin resistant Staphylococcus aureus (MRSA) among isolates from surgical site infections in Mulago hospital- Kampala, Uganda.
J Ojulong, T Mwambu, M Jolobo, E Agwu, F Bwanga, C Najjuka, D Kaddu-Mulindwa
J Ojulong, T Mwambu, M Jolobo, E Agwu, F Bwanga, C Najjuka, D Kaddu-Mulindwa. Prevalence of Methicillin resistant Staphylococcus aureus (MRSA) among isolates from surgical site infections in Mulago hospital- Kampala, Uganda.. The Internet Journal of Infectious Diseases. 2008 Volume 7 Number 2.
In Europe, MRSA prevalence ranges from over 50% in Portugal and Italy to below 2% in Switzerland and the Netherlands, where infection control measures have been shown to work (Verhoef
MRSA infections are of special concern because these infections are associated with prolonged hospital stay, increased hospital costs, and have a few therapeutic options for affected patients (Saxen
Materials And Methods
Study setting. The present study was carried out at Mulago National referral Hospital,
Kampala, Uganda, between February and May 2007. All patients (
underwent elective and emergency surgery during the study period were enrolled. Each of them had a pus swab
Sterile dry cotton swabs with Amies transport media (DELTALAB Rubi, Spain) were used to collect staphylococci from active part of infected surgical wounds or pus discharge. The swab was rolled gently but firmly on the base of the wound while applying an even pressure. The swab was replaced in its sheath which has transport medium and then transported to the laboratory where it was inoculated directly on phenol red mannitol salt agar (Liofilchem, Italy) and incubated at 37°C for 24 hrs.
According to previous report (NCCLS, 2003), Oxacillin salt agar (containing Mueller-Hinton agar (SIGMA) plates with 4% NaCl and 6 µg of oxacillin per ml) screening of Staphylococcus aureus isolates yielded positive results. All isolated identified Staphylococcus strains were frozen at -20oC until all isolates were obtained and ready for molecular analysis.
Molecular detection of A gene
The PCR mixture contained PCR buffer (ABgene, UK) supplemented with MgCl2 (25mM) and primers, 200 mM dTTP, dATP, dCTP, and dGTP. The contents were mixed in thin walled PCR tubes and the reaction mixture was placed in a DNA thermal cycler (Peltier PTC-200) to be amplified in 31 repeating cycles, each cycle having three basic steps: 1-min denaturation at 94oC followed by annealing for 30 s at 55oC and elongation for 1 min at 72oC. The samples were held in the thermal cycler at 4oC until they were loaded onto a 1.5% agarose gel and were electrophoresed for 1hr at 120 V, stained with ethidium bromide, and viewed with UV light. The presence of a 162-bp band was considered a positive result. The marker used was 100kbp (New England- Biotech)
Quality control strains
The following control strains were used for both oxacillin agar screen and PCR method;
Data collection and Management
The principle investigator, assisted by research assistants collected data. Informed consent was obtained and a standardized questionnaire was administered. The data collected included age, sex, date and time of collection and patient number. Other data collection was the presence or absence of MRSA after oxacillin agar screen and PCR.
The data was then analyzed using STATA statistical software. Dichotomous variables were compared using a chi square, and continuous variables were compared using multivariate statistic, with the help of a statistician.
Of the 188 patients enrolled, 62.9% of these patients were males and 37.1% were females. The average age of the patients was 31years with a range of 13 - 87 years. Fifty four (28.7%) patients had
In our study and out of 17 isolates positive for MSRA, 13 (76.5%) male patients were infected with MRSA more than 4 (23.5%) females. This confirms earlier report (Agwu
In this study, the prevalence of MRSA among
According to a review by Swierzewski, J.S. (2008), the population at increased risk of health-care associated MRSA infection includes: patients who have recently been hospitalized (within the past year) and patients in long-term health care facilities, including nursing homes and dialysis centers. Medical conditions that weaken the immune system (e.g., HIV/AIDS, cancer), recent invasive medical procedures (e.g., surgery, catheterization, dialysis), and recent use of antibiotics also increases the risk for HA-MRSA. Health care workers (e.g., doctors, nurses, physician assistants) and people who are in close contact with health care workers are at increased risk for developing staph infections, including MRSA. Children also have a higher risk for infection, possibly because their immune systems are not fully developed.
It appears there is a decline in the overall ability of different healthcare settings to stop or reduce the spread of MRSA to the barest minimum. In developing countries, it has always been contended that the inappropriate use of antibiotics for community infections may increase the prevalence of resistant bacteria infection (Agwu
This study has opened a broad research horizon that will enable future researchers to investigate: the source of MRSA; the link between MRSA acquisition and various factors like age, sex, occupation, ethnicity, geographical location, hospitalization, antibiotic usage, surgery and distinction between community-acquired MRSA and hospital acquired MRSA.