Infection in the Hospital Environment

Aman Ullah (Lecturer)B.Sc. Med. Lab. TechnologyPhD Research Scholar (Microbiology)Certificate in Health Professional Education Institute of Paramedical Sciences, Khyber Medical University, Peshawar, Pakistan

Introduction

• Infection is a major cause of mortality and morbidity in patients admitted to hospital

• The most frequent types of infection are urinary tract, respiratory, wound, skin and soft-tissue infections, and septicaemia, which is often associated with vascular access

The Environment

Food supply• Food is usually prepared centrally in the hospital kitchens• Patients are at risk of food-borne infection if hygiene

standards fall; this route can transmit antibiotic-resistant organisms to immunocompromised patients who are especially vulnerable

Air supply• Pathogens (e.g. multidrug-resistant tuberculosis,

respiratory viruses or bacteria) may be transmitted via theatre air supply and air-conditioning systems

• Badly maintained air-conditioning systems may be a source of Legionella

The Environment

Fomites• Any inanimate object may be contaminated with organisms

and act as a vehicle (fomite) for transmission• This is important for doctors performing procedures on

patients with instruments that might be contaminated and transmit infection

Water supply• The water supply in a hospital is a complex system,

supplying water to wash-hand basins and showers, central heating and air conditioning systems

• Legionella spp. may colonize the system in redundant areas of pipework and cooling-tower systems are a particular risk

The Host

• Hospital patients are susceptible to infection as a result of underlying illness or treatment

• Age and immobility may predispose to infection

Medical Activities

Intravenous access• This is the most frequent source of healthcare-associated bacteraemia.• The risk of infection from any intravenous device increases with the length

of time it remains in position• Cannula-related infection can be complicated by septicaemia, endocarditis • The risk of sepsis can be reduced by aseptic technique at insertion• The cannula site should be regularly inspected and this is particularly

important in unconscious patientsUrinary catheters• Indwelling urinary catheters bypass the normal defences and provide a

route for ascending infection into the bladder• Risks can be minimized by aseptic technique wh en the catheter is

inserted and handled

Medical Activities

Respiratory• Intubation bypasses the defences of the respiratory tract• Postoperative pain, immobility and the effects of anaesthesia

predispose to pneumonia by reducing coughing• Inhalation of oral contents is reduced by raising the head of the bed

in seriously ill patientsSurgery• Surgical patients often have other health problems that are

unrelated to their surgical complaint which may predispose them to infection

• Surgery is traumatic and carries a risk of infection• Complications of the procedure may increase risks• The preoperative period should be short to reduce the risk of

acquiring resistant hospital organisms

Medical Activities

• To minimize the risk of infection during an operation, theatres are supplied with a filtered air supply

• Staff movement during procedures should be limited to reduce air disturbance

• Changing clothing reduces transmission of organisms from the wards

• Impervious materials reduce contamination from the skin of the surgical team but are uncomfortable to wear

Antibiotic prophylaxis• Antibiotic prophylaxis reduces postoperative infection

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