Abstract

Strains of Staphylococcus aureus are very adaptable, and so far, many have acquired resistance to one or more antibiotics. S. aureus is found on most surfaces especially in public areas like hospitals and schools and on frequently touched areas like toilet and classroom door handles. Methicillin-resistant S. aureus (MRSA) is a strain of S. aureus which is resistant to methicillin. MRSA in the community presents a significant reservoir that could enter into healthcare facilities and spread among patients and also is a health risk for immunosuppressed populations. This study aimed at determining the prevalence of MRSA isolated from toilet and classroom door handles as a potential source of infection to the students and the workers in the University of Buea. From April to August 2019, Swabs were collected from 306 door handles and transported to the Laboratory for Emerging Infectious Diseases (LEID), University of Buea. Samples were inoculated on mannitol salt agar, subcultured on nutrient agar and identified using a combination of microscopic and biochemical methods. Disk diffusion method with oxacillin was used to isolate MRSA species. Antimicrobial susceptibility testing was used to characterize the MRSA isolates and multiple-antibiotic resistance (MAR) index for all MRSA isolates calculated. Overall, S. aureus was isolated from 252(82.4%) of the 306 samples. Of the 252 S. aureus strains, 39(15.5%) were MRSA. The MRSA comprise 9.9% from classroom doors and 24.9% from toilet door handles. Penicillin resistance (n=39, 100 %), was recorded highest followed by ceftriaxone (n=38, 97.4 %), gentamycin (n= 20, 51.3%) and tetracyclin (n=17, 43.6 %). Multiple-antibiotic resistance was observed in all (100%) MRSA isolates. MAR index ranged from 0.2 to 0.5. Fourteen antibiotypes were identified and the most prevalent was P_CRO (47%). These results emphasize the need to enhance hygienic measures in the University of Buea including hand washing and disinfection of all frequently touched surfaces.

CHAPTER ONE

INTRODUCTION AND LITERATURE REVIEW

1.1 Introduction

Staphylococcus aureus is a common cause of community and hospital acquired infections. One of the important sources of staphylococci for nosocomial infection is nasal carriage among hospital personnel (Rutvi et al., 2016).  Emergence and spread of S. aureus strains which are resistant to methicillin, referred to as methicillin-resistant S. aureus (MRSA) have resulted in high morbidity, high mortality and increased treatment costs (Kaur et al., 2012)

Methicilin-resistant Staphylococcus aureus (MRSA) is currently the most commonly identified antibiotic resistant pathogen in many parts of the world (Carvalho et al., 2010). Treatment of infection caused by S. aureus has become most difficult since the occurrence of methicillin resistance, as MRSA strains are resistant to all β-lactam antibiotics thereby significantly limiting treatment options (Ahmed et al., 2012). With a few exceptions, the incidence of nosocomial infection caused by MRSA continues to increase worldwide (Rutvi et al., 2016). Infections caused by MRSA strains are associated with longer hospital stay, prolonged antibiotic administration and higher cost than infections caused by methicillin-susceptible Staphylococcus aureus (Shiv et al., 2008). Colonized patients, colonized healthcare workers (HCWs) and contaminated environmental surfaces like bench tops, door handles and windows can act as reservoirs for the spread of MRSA to the other patients, healthy persons in the community and other HCWs (Gonsu et al., 2013).  Identification of patients, healthcare workers and environmental surfaces colonized with MRSA, combined with hand hygiene and other precautions have been shown to be effective in reducing the transmission and controlling the spread of MRSA (Rutvi et al., 2016).

1.2. Rationale

In the past 10 years, MRSA has become a major nosocomial pathogen for patients in hospitals and nursing homes (Chambers and DeLeo, 2009). Also, community-acquired MRSA (CA-MRSA) infections are on the rise, and the transmission of MRSA from the community and beyond acute care hospital environments is receiving more attention in the public health write-ups (Cooke and Brown, 2010). It is also very well documented that transmission occurs primarily from person-to-person by direct skin contact, and there is increasing evidence that contact with contaminated environmental surfaces is a significant transmission factor (Otter et al., 2011). The presence of MRSA in a community set up such as schools has both social and economic impact to the Country.  The cost incurred for treatment and managing the infection of MRSA by both the individual and the government is high and can be avoided. Surveillance of the presence of MRSA in community would greatly benefit both parties.  The government can use this study and other ways to do regular surveillance to determine the presence of MRSA and also other infections of public health importance.  Data on prevalence of MRSA in the University of Buea (UB), as a possible reservoir in community is lacking and yet students are more likely to transfer the MRSA from schools to their homes. This can help the health unit in UB and also the regional delegation of health in establishing prevention strategies such as hygiene in schools. Investigating carriage of MRSA will therefore be of very much importance as the UB community is made of so many persons from different backgrounds.

1.3. Hypothesis

Classroom and toilet door handles of the University of Buea carry methicillin-resistant Staphylococcus aureus.

1.4. Objectives

1.4.1 General Objective

The main objective of this study was to investigate the prevalence of MRSA on classroom and toilet door handles in the University of Buea.

1.4.2 Specific Objectives

The main objective of this study was accomplished through the following specific objectives:

1. To determine the prevalence of Staphylococcus aureus on classrooms and toilet door handles.
2. To determine the prevalence of MRSA and phenotypic antibiotic resistance profiles of the MRSA.
3. To determine the multiple antibiotic resistance (MAR) indices of the MRSA isolates.