INTRODUCTION
1.1 Background of the study
Nosocomial or hospital acquired infections (HAIs) is a serious global public health issue, causing the suffering of about 1.4 million people across the world at any given time (WHO 2007). Susceptibility to these infections has been associated with use of invasive devices, extremes of age, immune status and infection control practices (Haley et al 1985, Emori and Gayness 1995, Vincent et al 1995).They often increase costs of health care both for patients and health services alike (Coello et al 1993, McCuckin et al 1999, Kim et al 2001). The World Health Organization offers several definitions of a nosocomial infection/ hospital –acquired infection:
An infection acquired in [a] hospital by a patient who was admitted for a reason other than that infection . An infection occurring in a patient in a hospital or other health care facility in whom the infection was not present or incubating at the time of admission. This includes infections acquired in the hospital but appearing after discharge, and also occupational infections among staff of the facility.
As a general timeline, infections occurring more than 48 hours after admission are usually considered nosocomial.  Nosocomial infections are also divided into two classes, endemic or epidemic. Most are endemic, meaning that they are at the level of usual occurrence within the setting. Epidemic infections occur when there is an unusual increase in infection above baseline for a specific infection or organism. Epidemiological studies report that nosocomial infections are caused by ubiquitous. pathogens such as bacteria (Lepelletier et aI., 2005), viruses (de-Oliveira et aI., 2005) and fungi(Trick et aI., 2002) present in air, surfaces or equipment. Nosocomial infections occur worldwide, both in the developed and developing world.  They are a significant burden to patients and public health.  They are a major cause of death and increased morbidity in hospitalized patients.  They may cause increased functional disability and emotional stress and may lead to conditions that reduce quality of life.  Not only do they affect the general health of patients, but they are also a huge burden financially.   The greatest contributors to these costs are the increased stays that patients with nosocomial infections require.  The increased length of stay varies from 3 days for gynecological procedures to 19.8 days for orthopedic procedures.  Other costs include additional drugs, the need for isolation, and the use of additional studies.  There are also indirect costs due to loss of work.
Nosocomial infections are most frequently infections of the urinary tract, surgical wounds, and the lower respiratory tract.  A World Health Organization prevalence study and other studies have shown that these infections most commonly occur in intensive care units and in acute surgical and orthopedic wards.  Infection rates are also higher in patients with increased susceptibility due to old age, underlying disease, or chemotherapy.
Patients are exposed to a variety of microorganisms during a hospital stay, but contact between a patient and an organism does not necessarily guarantee infection.  Other factors influence the nature and frequency of infections.  Organisms vary in resistance to antimicrobials and in intrinsic virulence.  Bacteria, viruses, fungi, and parasites can all cause nosocomial infections.  There are multiple ways of acquiring such an organism.  The organisms can be transferred from one patient to another (cross-infection).  They can be part of a patient’s own flora (endogenous infection).  They can be transferred from an inanimate object or from a substance recently contaminated by another human source (environmental transfer).  The organisms that cause most hospital acquired infections are common in the general population, in which setting they are relatively harmless.  They may cause no disease or a milder form of disease than in hospitalized patients.  This group includes Staphylococcus aureus, coagulase-negative staphylococci, enterococci, and Enterobacteria.  Factors that increase a patient’s susceptibility to nosocomial infections include young or old age, decreased immune resistance, underlying disease, and therapeutic and diagnostic interventions.
The organisms that cause nosocomial infections are often drug-resistant.  The regular use of antimicrobials for treatment therapy or prophylaxis promotes the development of resistance.  Through antimicrobial-driven selection and the exchange of genetic resistance elements, multi-drug resistant strains of bacteria emerge.  Antimicrobial-sensitive microorganism that are part of the endogenous flora are suppressed, while the resistant strains survive.  Many strains of pneumococci, staphylococci, enterococci, and tuberculosis are currently resistant to most or all antimicrobials which were once effective.
Health care workers (HCWs) are at a high risk of needle stick injuries and blood-borne pathogens as they perform their clinical activities in a hospital.3  They are exposed to blood borne pathogens, such as human immunodeficiency virus (HIV), hepatitis B (HBV) and hepatitis C (HCV) viruses, from sharp injuries and contacts with blood and other body fluids.
Many nosocomial infections are caused by pathogens transmitted from one patient to another, by way of healthcare workers who have not washed their hands, or who don’t observe simple hospital hygiene measures, and also between patients (Horn et al 1988). Consequently, it is important to note that approximately one-third of hospital-acquired infections may be preventable (Comptroller and Auditor General 2000)