Infection control and prevention is the practice of implementing measures to prevent or reduce the transmission of infectious diseases in healthcare settings and the general community. It involves a wide range of strategies, including hand hygiene, personal protective equipment (PPE), environmental cleaning, and the appropriate use of antibiotics. Infection control and prevention is crucial to ensuring the safety of patients, healthcare workers, and the general public. It helps to minimize the risk of healthcare-associated infections (HAIs) and the spread of infectious diseases in the community. Effective infection control and prevention requires a multi-faceted approach, involving education, training, and adherence to guidelines and best practices. This includes proper hand hygiene techniques, appropriate use of PPE, and the implementation of environmental cleaning and disinfection protocols. In addition, infection control and prevention also involves the appropriate use of antibiotics to minimize the development of antibiotic resistance. This includes the judicious use of antibiotics, as well as the development of alternative treatment options. Overall, infection control and prevention is an essential component of public health, and plays a critical role in reducing the spread of infectious diseases and protecting the health and well-being of individuals and communities.

1. INFECTION CONTROL AND
PREVENTION
Mr. Prajwal D. Ajmerkar
(NURSING TUTOR)

2. Introduction
Infection prevention and control measures aim to ensure the protection of those
who might be vulnerable to acquiring an infection both in the general community
and while receiving care due to health problems, in a range of settings. The basic
principle of infection prevention and control is hygiene.

3. Chain Of Infection

4. An infection will develop if this chain remains intact. Nurses use infection prevention and
control practices to break the chain so that infection will not develop.
1) Infectious agent: Microorganisms include bacteria, viruses, fungi and protozoa. They
are the common infectious agents. The potential for microorganisms or parasites to
cause disease depends on the following factors:
-Sufficient number of organisms
-Virulence or ability to produce disease
-Ability to enter and survive to the host
-Susceptibility of host.

5. 2) Reservoir: A reservoir is where a pathogen can survive. Skin of patients,
carriers, animals, food, water insects, and inanimate objects are common
reservoirs of infection.
3) Portal of exit: Microorganisms can enter through a variety of sites such as skin
and mucous membrane, respiratory tract, urinary tract,gastritis tract, reproductive
tract and blood.
4) Mode of transmission: Direct contact or indirect contact with infected source,
contaminated air, water, blood, food, flies, mosquito are the common modes of
transmission to infection. Major mode of transmission of microorganisms occurs
in the hands of the health care providers.

6. 5) Portal Of entry: organisms can enter the body through skin, mucous
membranes, respiratory tract, gastrointestinal tract, reproductive tract and
blood.
6) Susceptible host: Whether a person acquires an infection agent.
Susceptibility depends on the individual degree of resistance to a pathogen.
The susceptibility of host depends upon the virulence of microorganisms
and immune status of the host.

7. Types of Infection
Sr. No. Types Definition/description Example
1 Primary Initial infection with a parasite Shigella dysenteriae
2 Secondary Primary infection lowers the resistance of the host and later gets
infection with another microorganisms
Bacterial pneumonia following
viral lung infection
3 Re infection Subsequent infection with same parasites in the same host Dysentery
4 Cross Patient suffer from a disease and new infection is set up from
another source
Cold
5 Nosocomial Cross infection occurring in hospitals Pneumatic
6 Iatrogenic or Physician
induced
Infection is acquired during therapeutic or investigative
procedures. Cold

8. 7 Focal Infection at localised sites like appendix & tonsils, general effects are
produced
Tonsillitis
8 Subclinical Clinical symptoms of an infection are not apparent. Asymptomatic gonorrhea in
women and men
9 Local Invading microorganisms are limited to a relatively small area of the
body.
Boils and abscesses
10 Systemic Microorganisms or their products are spread throughout the body by
blood or lymph
Measles
11 Mixed Two or more microbes infecting same tissue’s Anaerobic abscess (E.coli & B.
fragility).
12 Acute Have a short duration Pharyngitis

9. 13 Chronic Have a long duration Tuberculosis
14 Pyrogenic Pus forming Streptococcal infection
15 Fulminating Occur suddenly and with severe intensity Cerebrospinal meningitis
16 Latent Parasite after infection remains in a latent or hidden form and
produces clinical diseases when the host resistance is lowered
Typhoid fever

10. STAGES / COURSE OF INFECTION
1) Incubation period: interval between entrance of pathogen into body and appearance of first symptom, (e.g.,
chickenpox 2-3 weeks, common cold 1-2 days.)
2) Prodromal stage: Interval from onset of non-specific signs and symptoms (Malaise, low grade fever, fatigue) to
more specific symptoms. During this time, microorganisms grow and multiply and patient is more capable of
spreading disease to others.
3) Illness stage: Interval when patient manifests signs and symptoms specific to a particular disease,
e.g., Common Cold: sore throat, sinus, congestion, rhinitis.
Mumps: earache, high fever, parotid and salivary gland swelling. The severity of patient’s illness depends on the
extent of infection, the pathogenicity of the microorganisms and susceptibility of individuals.
1) Convalescence: Interval when acute symptoms of infection disappear until the individual regains his normal health.
Length of recovery depends on severity of infection and patient’s general health status. Recovery may take several
days to months.

11. FACTORS INCREASING SUSCEPTIBILITY TO MICROORGANISMS
1) GENETIC FACTOR:- The immune response is under genetic control and
differences in immune response to the same antigen shown by different
individuals in a species are determined by genetic differences.
The term ‘responder’ and ‘non-responder’ are used to describe the
individuals capacity to respond to a particular antigen. The Ir (immune
response) genes control this property.
1) AGE:- The embryo is immunologically immature. The capacity to produce
antibodies starts only with the development and differentiation of lymphoid
organs. During embryonic life, the developing lymphoid cells come into
contact with all the tissue antigens are eliminated

12. 3) Immunocompetence: This is not complete at birth, but continues to develop as
the infant grows. The infant has to depend on itself for antibody production from
the age of 3-6 months, by which time the maternal antibodies disappear.
However, full competence is acquired only by about 5-7 years for IgG and 10-15
years for IgA.
4) Nutritional Status: Malnutrition affects immune response adversely, though
serum components necessary for immunity are conserved selectively until the
nutritional deficiency becomes marked. Protein calorie malnutrition suppresses
both humoral and cellular immune response, the latter more severely.
Deficiencies of amino acids (tryptophan, phenylalanine, methionine, glycine,
isoleucine) and Vitamins (vitamin A and B, riboflavin, pyridoxine, pantothenic
acid, frolic acid.)

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5) Route for administration: Humoral immune response is better when the
antigens are administered parenterally then through oral or nasal routes. Large
particulate antigens such as bacteria or erythrocytes are more effective when
injected into tissue. The route of administration may also influence the type of
antibody produced.
The oral or nasal route is suitable for the production of IgA antibodies. Inhalation
of pollen antigens induces IgE synthesis, where as the same antigens introduced
parenterally lead to the production of IgG antibodies.

14. •
6) Site of administration: With some antigens, the site of injection seems
relevant. The hepatitis B vaccine is less immunogenic following gluteal injection
than following injection into the deltoid. This may be due to the paucity of
antigen- presenting cells in gluteal fat, delaying the presentation of the antigen to
T and B cells.
7) Size and number of doses: Antibody response is dependent on the dose of an
antigen which is effective only above a minimum critical dose. Further increase in
dose enhances the intensity of antibody response. However, beyond certain level,
increase in the dose of antigen does not improve the antibody response; instead,
such an increase may even inhibit the antibody response and induce tolerance.
This phenomenon is designated as immunological paralysis.

15. •
8) Multiple antigens: When two or more antigens are administered
simultaneously, the effects may vary. Antibodies may be produced against the
different antigens as though they had been given separately, or antibody
response to one or other of the antigens may be enhanced and response to the
other may be diminished (antigenic competition)

16. Inflammatory response: Any injury, including an invasion by microorganisms, causes inflammation in the
affected area. Inflammation, a complex reaction, results from many different conditions. The damaged
tissue releases substances that cause inflammation and that direct the immune system to do the
following:
● Wall of the area.
● Attack and kill any invaders.
● Dispose of dead and damaged tissue.
● Begin the process of repair.
However, inflammation may not be able to overcome large numbers of microorganisms. During
inflammation, the blood supply increases. An infected area near the surface of the body becomes red
and warm. The walls of the blood vessels become more porous, allowing fluid and white blood cells to
pass into the affected tissues.
BODY DEFENSES AGAINST INFECTION

17. •
The increase in fluid causes the inflamed tissue to swell. The white blood cells,
attacked the invading microorganisms and release substances that continue the
process of inflammation.
Other substances trigger clotting in the tiny vessels (capillaries) in the inflamed
area, which delays the spread of the infecting microorganisms and their toxins.
Many of the substances produced during inflammation stimulates the nerves,
causing pain. Reaction to the substances released during inflammation include
the chills, fever, and muscle aches that commonly accompany

18. Immune response
When an infection develops, the immune system response by producing several
substances and agents that are designed to attack the specific invading
microorganisms microorganisms. For example, the immune system may produce
killer T cells (a type of white blood cell) that can recognize and kill the invading
microorganisms.
Also, the immune system produces antibodies that target the specific invading
microorganisms. Antibodies attach to and immobilise microorganisms-killing
them outright or helping neutrophils target and kill them.

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