Carriage rate of methicillin resistant staphylococcus aureus among health care workers at The Kenyatta National Hospital

Abstract

Background: S.aureus is associated with many community and hospital acquired infections. Nasal carriage among HCWs is an important source of staphylococci that results in nosocomial infections. Infections caused by Methicillin resistant S.aureus are associated with longer hospital stay, prolonged antibiotic administration, greater costs than infections caused by methicillin susceptible S.aureus. In hospital settings, drug resistant strains especially MRSA have emerged leading to severe and fatal infections. There’s currently no data on carriage of MRSA among HCWs in Kenyan public hospitals. Objectives: This study sought to determine the prevalence and the risk factors associated with MRSA colonization among HCWs at Kenyatta National Hospital and also the antibiotic susceptibility profile of the isolates. Design: A cross sectional study Methodology: The study was conducted on a total of 180 health care HCWs at Kenyatta National hospital’s ICU, renal and Burns units and medical ward from 4th February 2015 to 3rd March 2015. Nasal and hand swabs were collected and cultured on Mannitol Salt Agar. Slide coagulase test was then performed, followed by an oxacillin susceptibility test on Mueller Hinton Agar using Kirby-Bauer disc diffusion method. Results: S.aureus was isolated in 40% of HCWs. Nasal and hand carriage was 25% and 15% respectively, while 5.6% had both nasal and hand carriage leaving an overall carriage rate of 34.4%.The S. aureus isolates showed high sensitivity to linezolid (98.4%), and gentamycin (96.8%).They showed high resistance to vancomycin (53.2%). Penicillin and ampicillin were the most resistant, (80.6% and 66.1%) respectively. Methicillin resistance was seen in 59.7% of the S.aureus isolates, both by the disc diffusion test and by the Oxacillin Resistance Screen Agar (ORSA) test ,but 4.8% of these represented both nasal and hand carriage, therefore, giving an overall carriage of 54.8% of the S.aureus isolates. This represented 18.9% of all the HCWs. There was a slightly higher preponderance for MRSA in the females (19.1%).The males had (18.5%).The highest carriage was in the medical ward (29.4%) while the lowest was in the renal unit (8.8%) Conclusions: There was a high rate of carriage of MRSA carriage among HCWs. Among the 4 units studied the carriage rate was highest in the medical ward. The S.aureus were most susceptible to Linezolid. In view of these findings we recommend enhanced periodic training of HCWs on control and prevention of infectious diseases, and also regular monitoring and review of antibiotics in order to ensure appropriate and rational use.