1. Hospital-acquired infections, also known as nosocomial infections, are a leading cause of preventable death in hospitals each year, with the CDC estimating around 2 million infections and 90,000 deaths annually. 2. Patients in healthcare settings are at risk of acquiring infections due to lowered immunity, exposure to microorganisms, and invasive procedures. 3. The immune system has three lines of defense against pathogens - physical and chemical barriers, nonspecific innate responses, and specific adaptive responses. The skin and mucous membranes act as physical barriers, while the innate system provides cellular defenses.

4.  Infection is one of the leading causes of preventable death in
hospitals every year.
 The centre of Disease Control and Prevention estimated that
there are approximately 2 million preventable infections in
hospital every year, leading to 90,000 unnecessary deaths.

5.  A patient entering in to health care settings is at risk for
acquiring infections because of lowered resistance to infection,
micro organisms and invasive procedures.
 The nurse comes in contact with a verity of micro organisms
and thus must practice infection control techniques to avoid
spreading them to client.

6.  Injurious contamination of body or parts of the body by
bacteria, viruses, fungi, protozoa and rickettsia or by the toxin
that they may produce infection.
 Infection may be local or generalized and spread throughout
the body.
 Once the infectious agent enters the host it begins to
proliferate and reacts with the defense mechanisms of the
body producing infection symptoms and signs: pain, swelling,
redness, functional disorders, rise in temperature and pulse
rate and leukocytosis.

7.  Micro-organisms - bacteria, fungi, viruses, protozoa and
worms
 Most are harmless [non-pathogenic]
 Pathogenic organisms can cause infection
 Infection exists when pathogenic organisms enter the body,
reproduce and cause disease

8. Micro organisms it may be a bacteria, a virus, a
parasite or a fungi.

10. 1.Incubation Period
 The incubation period occurs after the initial entry of the
pathogen into the host when it begins to multiply, but there are
insufficient numbers of the pathogen present to cause signs
and symptoms of disease.
 Incubation periods can vary from a day or two in acute disease
to months or years in chronic disease, depending upon the
pathogen.

11. During this incubation
period, the patient is
unaware that a disease is
beginning to develop.

12. Prodromal Period
 The prodromal period occurs after the incubation period.
 During this phase, the pathogen continues to multiply, and the
host begins to experience general signs and symptoms of
illness caused from activation of the nonspecific innate
immunity, such as not feeling well (malaise), low-grade fever,
pain, swelling, or inflammation.
 These signs and symptoms are often too general to indicate a
particular disease is occurring.

13. Acute Phase
 Following the prodromal period is the period of acute illness,
during which the signs and symptoms of a specific disease
become obvious and can become severe.
 This period of acute illness is followed by the period of
decline as the immune system overcomes the pathogen. The
number of pathogen particles begins to decline and thus the
signs and symptoms of illness begin to decrease.
 However, during the decline period, patients may become
susceptible to developing secondary infections because their
immune systems have been weakened by the primary
infection.

14. Convalescent Period
 The final period of disease is known as the convalescent
period.
 During this stage, the patient generally returns to normal daily
functioning, although some diseases may inflict permanent
damage that the body cannot fully repair.
 For example, if a strep infection becomes systemic and causes
a secondary infection of the patient’s heart valves, the heart
valves may never return to full function and heart failure may
develop.

15.  LOCAL: limited and specific part of the body
 SYSTEMIC: mode of infection spread and damage diffrent
parts of the body
 ACUTE: appears suddenly and lasts for short time
 CHRONIC: occurs slowly, over long period and may lasts
months or years.
 Bacteremia: The culture of blood reveals mode of infection
 Septicemia: when bacteremia results in systemic infection

16.  Age
 malnutrition
 genetics defects in immunity (WBC DISORDER)
 Medical diseases (diabetes, liver disease)
 chemotherapy agents
 implantation of prosthetic materials
 organ transplantation

17.  The human body has three
primary lines of defense to
fight against foreign
invaders, including
viruses, bacteria, and
fungi.
 The immune system’s
three lines of defense
include physical and
chemical barriers, non-
specific innate responses,
and specific adaptive
responses.

18.  The immune system is a complex network of specific immune
cells and proteins that work in synergy to protect the body
against foreign invaders and harmful toxic materials coming
from the environment.
 Foreign substances that trigger an immune response are called
antigens. However, under certain circumstances, such as in
autoimmune diseases, the immune system can be activated by
self-antigens, leading to the destruction of the body’s cellular
components.

19. There are two basic ways the body defends against pathogens:
nonspecific innate immunity and specific adaptive immunity.
 Nonspecific innate immunity is a system of defenses in the
body that targets invading pathogens in a nonspecific manner.
It is called “innate” because it is present from the moment we
are born. Nonspecific innate immunity includes physical
defenses, chemical defenses, and cellular defenses.

20. SKIN:-
 One of the body’s most important
physical barriers is the skin barrier,
which is composed of three layers of
closely packed cells.
 The topmost layer of skin called the
epidermis consists of cells that are
packed with keratin. Keratin makes the
skin’s surface mechanically tough and
resistant to degradation by bacteria.
Infections can occur when the skin
barrier is broken, allowing the entry of
opportunistic pathogens that infect the
skin tissue surrounding the wound and
possibly spread to deeper tissues

21.  Physical defenses : Physical defence are the body’s most
basic form of defense against infection. They include physical
barriers to microbes, such as skin and mucous membranes,
as well as mechanical defenses that physically remove
microbes and debris from areas of the body where they might
cause harm or infection. In addition, a person’s microbiome
provides physical protection against disease as normal flora
compete with pathogens for nutrients and cellular-binding
sites.

22.  MUCUS MEMBRANE:-
The mucous membranes lining the
nose, mouth, lungs, and urinary and
digestive tracts provide another
nonspecific barrier against potential
pathogens. Mucous membranes
consist of a layer of epithelial cells
bound by tight junctions. The
epithelial cells secrete a moist,
sticky substance called mucous.
Mucous covers and protects the
fragile cell layers beneath it and also
traps debris, including microbes.
Mucus secretions also contain
antimicrobial peptides

23.  For example, in the respiratory system, inhalation can bring
microbes, dust, mold spores, and other small airborne debris
into the body. This debris becomes trapped in the mucus
lining the respiratory tract. The epithelial cells lining the
upper parts of the respiratory tract have hair-like appendages
known as cilia. Movement of the cilia propels debris-laden
mucus out and away from the lungs.

24.  Like the respiratory tract, the digestive tract is a portal of entry
through which microbes enter the body, and the mucous membranes
lining the digestive tract provide a nonspecific physical barrier against
ingested microbes.
 The intestinal tract is lined with epithelial cells, interspersed with
mucus-secreting goblet cells. This mucus mixes with material received
from the stomach, trapping foodborne microbes and debris, and the
mechanical action of peristalsis (a series of muscular contractions in
the digestive tract) moves this mixture through the intestines and
excretes it in feces.
 For this reason, feces can contain microorganisms that can cause the
spread of infection; therefore, good hand hygiene is vital.

26. Adaptive immunity involves specialized immune
cells and antibodies that attack and destroy
foreign invaders and are able to prevent disease in
the future by remembering what those substances
look like and mounting a new immune response.

30.  Hospital acquired infection
is also called Nosocomial
infection or Healthcare-
associated infections.
 Nosocomial infections can
be defined as infection
acquired by the person in
the hospital, manifestation
of which may occur during
hospitalization or after
discharge from hospital.
 The person may be a
patient, members of the
hospital staff and/ or
visitors.