Nosocomial Infections

-Dr.Sharad H. GajuryalJunior Resident, MD (Hospital

Administration)BPKIHS, Dharan

Introduction

Nosocomial infection or Hospital acquired infections is an infection acquired during hospital care which are not present or incubating at the time of admission.

Infection occurring more than 48 hours after hospitalization are termed as hospital acquired infection.

They are major public health problem in hospital through out the world

HAI are major cause of morbidity and mortality in hospital.

Nosocomial infections not only involve patients but also any one who come in contact with hospital including staffs, visitors, workers and volunteers.

Majority of HAI are clinically apparent during hospitalization. However, the onset of disease can be present after patient has been discharged.

It should not be confused with infection with which patient has come to hospital for treatment. They are community acquired, unless they result from previous hospitalization.

Prevalence of Nosocomial Infection

They are the major cause of morbidity and mortality among hospitalized patients and are seen in both rich and poor countries.

A study done under WHO in 14 WHO regional countries in 55 different hospital showed that 8.7% of hospitalized patient had nosocomial infection. Highest frequency seen in East Meditterian and South East Asian Countries (11.8% and 10%)

Similarly the study done in Thailand (2005),Albania (2007), and Tanzania (2003) showed that the prevalence rate of HAI is 6-27%

According to Hospital Infection Society of India, the incidence of HAI in India is 5-30%.

It has been found that because of HAI, the patient occupy beds for an average of 15-20 days which results in increase in direct cost and opportunity cost to patients.

Most Common HAI

UTI- 30% SSI-15% PSI-10% VAP-10% BSI-15% NNS-10% Others-10%

Epidemiology of HAI

Agent Factor Host Factor Environmental Factor

Imbalance Between These Factors Leads to Disease Process

Agent Factor (Microorganisms)-Patients are exposed to various microorganisms during hospitalizations. Many different Bacteria, virus, fungi and parasites cause HAI.

These infections can be endogenous or exogenous. And some organisms may be acquired from any substance/equipment recently contaminated from another human source.

Large no. of HAI are due to gm—vet microorganisms.

Microorganisms like staphylococcus, e.coli, salmonella, shigella, pseudomonas , kleibseilla are increasing in involvement and are more cause of worry.

Host Factor(patient’s susceptibility) : It includes patient’s age , immune status , underlying disease and different diagnostic and therapeutic intervention which decrease the host defense of patient.

Patient with chronic disease like leukemia, malignant tumor, renal failure ,DM, AIDS are at risk of infection with opportunistic pathogens.(innocuous organisms)

Other risk factor includes :

MalnutritionImmuno suppresive drugs ChemotherapyIrradiation

Environmental Factors: Patient with infection are potential

source of infection to other patients and staffs.

Crowded condition of hospital, frequent transfer of patient and concentration of high risk patient in one area ,contribute the development of nosocomial infection.

EPIDEMIOLOGICAL TRIAD

ENV.

HOST AGENT

EPI .TRIAD

In any epidemiological triad , the agent, host and environment interacts and interplay, and any imbalance between these factors lead to disease process.

The same phenomenon is applicable to nosocomial infections also. where environment plays as a fulcrum .

The balancing pore is within environment of the hospital.

Bacterial Resistance

The wide spread use of antimicrobials for therapy and prophylaxis is major determinants to the resistance.

Many strains of pneumococci, staphyloococci,enterococci, TB are resistant to antimirobials which were once not used to be resistant.

Critical problem in developing countries where second line drugs are non-available or non- affordable.

Source of Infection & Transmission

1.Endogeneous infection – Bacteria from normal flora cause infection because of transmission outside to natural habitat.eg.UTI,Damage to tissue cause growth to c.difficle,yeast, Gm-ve patient causing SSI in pt. with abdominal surgery and pt. catheterized with UTI.

Exogenous Infection-Infections transmitted through patient-patient or patient –staff or staffs-patient through direct contact, air droplets or during patient caring.

Also transmitted through contaminated inanimate articles like thermometer,towel,Hanky,food and drinks,bed linen, hospital dust,equipment and instruments.

Important Factors Responsible for Nosocomial Infections

Faulty design of ward, inadequate lightening, inadequate ventilation

Non avaibility of isolation ward Non avaibility of separate dirty utility room Crowding in hospital Universal precaution not practiced well Lack of inadequate hand washing Poor hygiene practice of patients, staffs and

visit Poor housekeeping service ,dietary and

waste disposal service of hospital.