INTRODUCTION
Hospital acquired infections are a significant burden, both the patient and for public health. Patient
care is provided medical setups ranging from highly equipped clinics and to government hospitals and
primary health centers HCs) having basic facilities only. Hospital-acquired infections add to
functional disability and emotional stress of the patient and in some cases may to disabling conditions
that reduce the quality of life also one of the leading causes of death. Prolonged hospiatal stay not
only increases direct costs to the patients or the payers also indirect costs due to loss in work. The
increased use drugs, the need for isolation, and the use of additional and other diagnostic studies also
contribute . HAIs occur worldwide and affect both developed and -poor countries. Many different
pathogens may cause.
DEFINITION
Hospital acquired infection which were not present in a person at the time admission to a
hospital but are acquired during a stay in the hospital. Infections mainly occur after 48 hours
of admission and up to 30 days after procedure / discharge from the hospital
Infection related operative procedure that occurs at or near surgical incision within 30
days of procedure or within 90 days if prosthetic materia were implanted
EPIDEMIOLOGY
In developed countries, between 5 to 10 percent of patients acquire one or more HCAI
infections; in the developing countries, this can be as high as 25%. The risk of healthcare-
associated infection in such countries is 2 to 20 times higher than in developed countries.
FACTORS CONTRIBUTING TO HAI’S
Low immune status either due to therapy or disease.
Increased use of transfusion products, antimicrobial agents and immunosuppressive
therapies.
Increase in use of medical devices, such as catheters and ventilators.
Increase in complicated surgeries due to advances in medical sciences and
complications following them.
Transmission between patients and healthcare workers.
Antimicrobial misuse and overuse causing higher rates of antimicrobial resistance.
Increased workload of healthcare workers.
Factors Associated with Patient
Age: The extremes of life, i.e., infancy and old age are associated with a decreased
resistance to infection.
Underlying disease: Patients with chronic disease, such as malignant tumours,
leukaemia, diabetes mellitus, renal failure or the acquired immunodeficiency
syndrome (AIDS) have an increased susceptibility to infections with opportunistic
pathogens.
Immune status: Immunosuppressive drugs, irradiation and malnutrition may lower
resistance to infection. Injuries to skin or mucus membranes also affect natural defense
mechanisms.
, Diagnostic and therapeutic procedures: Many modern diagnostic and therapeutic
procedures, such as biopsies, endoscopic examinations, catheterization, intubation,
ventilation, suction and surgical procedures increase the risk of infection.
Patients with infections or carriers of pathogenic microorganisms admitted to hospital
are potential sources of infection for patients and staff.
·OTHER FACTORS
PATHOGENIC ORGANISMS
Like different bacteria, viruses, fungus and parasites.
SOURCES MAINLY FROM
Cross infection- From another person
Healthcare-associated infections causing HCAI can originate from endogenous or exogenous
sources.
Endogenous sources refer to body sites colonised by commensal bacteria. These include skin,
gastrointestinal tract, upper respiratory tract, oral cavity or vagina.
Exogenous sources include patients' environment such as healthcare workers, visitors,
patient-care equipment or medical devices.
COMMON MICROBES CAUSING HCAI
Bacteria: Pathogenic bacteria are more virulent and cause infections regardless of the host's
status. These are the most common nosocomial pathogens. Some commensal bacteria may
cause infection if a person is immunocompromised, Staphyloccocic e.g., cutaneous coagulase
negative Staphylococci cause Escherichia coli, bloodstream infection that is attributed to an
intravascular catheter infection and intestinal Escherichia coli is the most common cause of
urinary infection. The HAI causing bacteria are enlisted in Table 32.1.
TABLE 32.1: Bacteria associated with nosocomial infections
High Yield ropes
Types of infections
Pneumonia- Klebsiella pneumoniae, Pseudomonas aeruginosa, Staph aureus, E. coli and
Enterobacter species, Legionella
Surgical wounds- Streptococcus faecalis, S. aureus, E. coli
Intravenous catheters -S. epidermidis, S. aureus, Streptococcus faecalis, Candida species
Urinary catheters -E. coli, Streptococcus faecalis, Pseudomonas aeruginosa, Klebsiella,
Serratia marcescens.
Hospital acquired infections are a significant burden, both the patient and for public health. Patient
care is provided medical setups ranging from highly equipped clinics and to government hospitals and
primary health centers HCs) having basic facilities only. Hospital-acquired infections add to
functional disability and emotional stress of the patient and in some cases may to disabling conditions
that reduce the quality of life also one of the leading causes of death. Prolonged hospiatal stay not
only increases direct costs to the patients or the payers also indirect costs due to loss in work. The
increased use drugs, the need for isolation, and the use of additional and other diagnostic studies also
contribute . HAIs occur worldwide and affect both developed and -poor countries. Many different
pathogens may cause.
DEFINITION
Hospital acquired infection which were not present in a person at the time admission to a
hospital but are acquired during a stay in the hospital. Infections mainly occur after 48 hours
of admission and up to 30 days after procedure / discharge from the hospital
Infection related operative procedure that occurs at or near surgical incision within 30
days of procedure or within 90 days if prosthetic materia were implanted
EPIDEMIOLOGY
In developed countries, between 5 to 10 percent of patients acquire one or more HCAI
infections; in the developing countries, this can be as high as 25%. The risk of healthcare-
associated infection in such countries is 2 to 20 times higher than in developed countries.
FACTORS CONTRIBUTING TO HAI’S
Low immune status either due to therapy or disease.
Increased use of transfusion products, antimicrobial agents and immunosuppressive
therapies.
Increase in use of medical devices, such as catheters and ventilators.
Increase in complicated surgeries due to advances in medical sciences and
complications following them.
Transmission between patients and healthcare workers.
Antimicrobial misuse and overuse causing higher rates of antimicrobial resistance.
Increased workload of healthcare workers.
Factors Associated with Patient
Age: The extremes of life, i.e., infancy and old age are associated with a decreased
resistance to infection.
Underlying disease: Patients with chronic disease, such as malignant tumours,
leukaemia, diabetes mellitus, renal failure or the acquired immunodeficiency
syndrome (AIDS) have an increased susceptibility to infections with opportunistic
pathogens.
Immune status: Immunosuppressive drugs, irradiation and malnutrition may lower
resistance to infection. Injuries to skin or mucus membranes also affect natural defense
mechanisms.
, Diagnostic and therapeutic procedures: Many modern diagnostic and therapeutic
procedures, such as biopsies, endoscopic examinations, catheterization, intubation,
ventilation, suction and surgical procedures increase the risk of infection.
Patients with infections or carriers of pathogenic microorganisms admitted to hospital
are potential sources of infection for patients and staff.
·OTHER FACTORS
PATHOGENIC ORGANISMS
Like different bacteria, viruses, fungus and parasites.
SOURCES MAINLY FROM
Cross infection- From another person
Healthcare-associated infections causing HCAI can originate from endogenous or exogenous
sources.
Endogenous sources refer to body sites colonised by commensal bacteria. These include skin,
gastrointestinal tract, upper respiratory tract, oral cavity or vagina.
Exogenous sources include patients' environment such as healthcare workers, visitors,
patient-care equipment or medical devices.
COMMON MICROBES CAUSING HCAI
Bacteria: Pathogenic bacteria are more virulent and cause infections regardless of the host's
status. These are the most common nosocomial pathogens. Some commensal bacteria may
cause infection if a person is immunocompromised, Staphyloccocic e.g., cutaneous coagulase
negative Staphylococci cause Escherichia coli, bloodstream infection that is attributed to an
intravascular catheter infection and intestinal Escherichia coli is the most common cause of
urinary infection. The HAI causing bacteria are enlisted in Table 32.1.
TABLE 32.1: Bacteria associated with nosocomial infections
High Yield ropes
Types of infections
Pneumonia- Klebsiella pneumoniae, Pseudomonas aeruginosa, Staph aureus, E. coli and
Enterobacter species, Legionella
Surgical wounds- Streptococcus faecalis, S. aureus, E. coli
Intravenous catheters -S. epidermidis, S. aureus, Streptococcus faecalis, Candida species
Urinary catheters -E. coli, Streptococcus faecalis, Pseudomonas aeruginosa, Klebsiella,
Serratia marcescens.
