II: HOST & MICROORGANISM INTERACTION

Infection

the introduction and uninhibited multiplication of a microorganism on or within a host

1. Endogenous Infection

2. Exogenous Infection

3. Nosocomial Infection

4. Healthcare-associated Infection

4 Types of Infection

Endogenous Infection

Result from microorganisms that are part of the patient’s normal flora

Exogenous Infection

infections occur from microorganisms with an external source

Nosocomial Infection

refers to an infection acquired in the hospital or healthcare setting

Healthcare-associated Infection (HAI)

a broader term that is used to describe those infections acquired while receiving health care for another condition

Infectious dx

the host dysfunction and tissue or organ damage caused by an infection, which typically manifests with medically significant symptoms

Etiologic/Causative Agent

a microorganism that causes the infection or disease

Reservoir of Infection

refers to the origin of the etiologic agent such as contaminated food, water, animals, or other humans

Pathogen

microorganisms (bacterium, virus, fungus, or parasite) that are capable of causing infectious disease

Primary / True Pathogen

has the ability to cause disease in a host regardless of the host’s immune system status or normal microbiota

Opportunistic Pathogen

can cause disease only in situations that compromise the host’s defenses

Normal Microbiota / Normal Flora / Indigenous Microbiota

refers to microorganisms that are regularly found at a particular anatomic site and generally do not cause infection

Incidence

a disease refers to the number of individuals infected in a population or the number of new cases in a population

Prevalence

describes the percentage of infected individuals in a given population at a given time

Endemic

when a disease consistently occurs at a constant rate in a given location

e.g., Malaria in Palawan

Epidemic

occurs when there are a larger number of cases of a disease in a given location

e.g., Cholera in Pasay

Pandemics

epidemics that occur around the world

Outbreaks

refer to instances where there is a disproportionately larger number of infected individuals in a fairly short amount of time

Morbidity

refers to the effects of the disease on the host such as organ damage

Mortality

incidence in which a disease causes death

Symptom

an indication of a disease that is experienced by a patient

Symptom

identify if symptom / sign

pain

Symptom

identify if symptom / sign

fever

Sign

an indicator of the disease observed by the healthcare provider

Biosafety Levels

used to identify the protective measures needed in a laboratory setting to protect workers, the environment, and the public

Biosafety Levels

levels are defined by BMBL

Biosafety Level I

Biosafety Level II

Biosafety Level III

Biosafety Level IV

Biosafety Levels

Biosafety Level I

-        Lab contaminants

Biosafety Level I

-        Those with no known potential of infecting healthy people

o  Bacillus subtilis

o  Mycobacterium gordonae

o  Naegleria gruberi

examples of Biosafety Level I

Biosafety Level I

Threat to Lab Workers

Minimal

Biosafety Level I

Laboratory Features

• Basic safety procedures, called Standard Microbiological Practices,

• Require no special equipment or design features

Biosafety Level II

Acquired thru ingestion, mucous membrane, percutaneous exposure

Biosafety Level II

Threat to Lab Workers

Moderate

Biosafety Level II

Threat to Lab Workers

BSL-1 practices + lab coats, protective gloves, limited access, decontamination of all infectious waste, & biohazard warning signs

Biosafety Level II

Laboratory Features

• Hand washing sinks, eye washing stations in case of accidents, & doors that close automatically & lock.

• Equipment that can decontaminate laboratory waste, including an incinerator, an autoclave, and/or another method, depending on the biological risk assessment.

o  Bacillus anthracis

o  Staphylococcus

o  Enteric pathogens like Salmonella & Shigella

o  Viruses like HIV & HBV

examples of BSL II

Biosafety Level III

With potential for aerosol transmission (inhalation)

Biosafety Level III

Threat to Lab Workers

Highest Risk

Biosafety Level III

Threat to Lab Workers

BSL-2 practices + special lab clothing & controlled access

Biosafety Level III

Laboratory Features

• Must use controlled, or "directional," air flow to ensure that air flows from non-laboratory areas (such as the hallway) into laboratory areas

• Use of two self-closing, or interlocked, doors, sealed windows & wall surfaces, & filtered ventilation systems & BSL-2 lab features

o  Mycobacterium tuberculosis

o  Rickettsia

o  Francisella tularensi

o  Brucella

o  Coxiella

o  Coccidioides immitis

o  Viruses like St. Louis Encephalitis virus

examples of Biosafety Level III

Biosafety Level IV

-        Can cause life-threatening dx

Biosafety Level IV

Organisms encountered in research institutions

Biosafety Level IV

Threat to Lab Workers

Extreme Risk

Biosafety Level IV

Threat to Lab Workers

BSL-3 practices + entrance to a separate room where street clothing is changed & replaced with lab clothing; includes decontamination of all personnel & material before leaving the area

Biosafety Level IV

Laboratory Features

• Cabinet Laboratory – tests are done in a Class III Biosafety Cabinet

Biosafety Level IV

Laboratory Features

• Suit Laboratory – personnel are required to wear full-body, air-supplied suits, which are the most sophisticated type of PPE.

o  MERS-COV

o  Ebola

o  Filovirus

o  Arenavirus

o  Arbovirus

o  Small Pox Virus

examples of Biosafety Level IV

Biological Safety Cabinet

maintains a clean working environment by filtering the air with high-efficiency particulate air (HEPA) filters (Jagtap, et al., 2023).

Biological Safety Cabinet I

Biological Safety Cabinet II /

Vertical Laminar Flow

Biological Safety Cabinet III

Biological Safety Cabinet

Biological Safety Cabinet I

-        – Pressure, ventilated cabinet

Biological Safety Cabinet I

-        Unsterilized air enters & circulates within the cabinet, & the exhaust air from the cabinet is filtered by HEPA filter

Biological Safety Cabinet I

-        Has the least protection because it is entirely open

Biological Safety Cabinet I

Protect the worker & environment, not the organism

Biological Safety Cabinet I

Sterilizes Air To Be

Exhausted

Biological Safety Cabinet I

Process

• Non-Pathogens

• (Bsl-1) Low Oncogenic Virus

• Low Toxic Chemicals

·   1 HEPA Filter

Biological Safety Cabinet I has how many HEPA filter

0.3 um

HEPA Filter of Biological Safety Cabinet I

Pore size

75 linear feet/min

HEPA Filter of Biological Safety Cabinet I

Air velocity

IIA: Fixed Opening

IIB: Variable Sash

Types of Biological Safety Cabinet II / Vertical Laminar Flow

IIA: Fixed Opening

- Exhaust air inside the room

- 70% of air recirculated

• IIA1: 75 LFM

• IIA2: 100 LFM

Types of IIA: Fixed Opening

75 LFM

IIA: Fixed Opening

IIA1:

100 LFM

IIA: Fixed Opening

IIA2:

IIB: Variable Sash

- Exhaust air is discharged outside the building

- Protects the air, environment & the culture

75 – 100 linear feet/min

- Air Velocity of IIB: Variable Sash

• IIB1: 70% exhausted, 30% recirculated

• IIB2: 100% exhausted

Types of IIB: Variable Sash

70% exhausted, 30% recirculated

IIB: Variable Sash

IIB1:

100% exhausted

IIB: Variable Sash

IIB2:

Biological Safety Cabinet II /

Vertical Laminar Flow

Sterilzes air to be Exhausted & the air that flows over the infectious material

Biological Safety Cabinet II /

Vertical Laminar Flow

Process

• Bacterial & Fungal Pathogens

• Medium Risk Oncogenic Virus

• Chemicals

• Carcinogens (BSL-2)

Biological Safety Cabinet II /

Vertical Laminar Flow

Biological Safety Cabinet III

Process

• Viral Pathogen (BLS-3)

Biological Safety Cabinet III

- Most effective because the system is entirely closed

Biological Safety Cabinet III

Infectious material is handled using gloves attached & sealed to the cabinet.

Biological Safety Cabinet III

- Highly toxic materials

Biological Safety Cabinet III

- Entire room is with – pressure

Biological Safety Cabinet III

Sterilization

destruction and removal of all forms of microbial life including their spores

1. Moist Heat

2. Dry Heat

3. Titration

4. Ionizing radiation / Cold Sterilization

Physical Method of Sterilization

o Autoclave

o Tyndallization

o Inspissation

Moist Heat

o Direct flaming

o Incineration

o Cremation

o Oven

Dry Heat

a. Ethylene Oxide (Gas Sterilant)

b. Formaldehyde vapor and vapor phase H202

c. 2% glutaraldehyde

d.Peracetic acid

Chemical Method of Sterilization

DISINFECTION

Refers to the destruction and removal of the pathogen but NOT NECESSARILY ALL MICROORGANISMS AND THEIR SPORES

a. Pasteurization

b .Boiling

c .U V

Physical Method of Disinfection

1. Antiseptics

2. Disinfectant

Chemical Method of Disinfection

1. Alcohols

2. lodophors

3. Chlorohexidine

4. Hexachlorophene

5. 10% hydrogen peroxide

Antiseptics

Disinfectant

1. Halogens (Chlorine,lodine, Fluorine)

2. Heavy metals

3. Aldehydes

4. QUATS (Quaternary Ammonium Compounds)

5. Phenolics

Disinfectant

Autoclave

Principle: acts by coagulating or denaturing enzymes and proteins

Autoclave

121 °C, 15 psi, 30-60 minutes for medical waste and unused media

121 °C, 15 psi, 30-60 minutes for medical waste and unused media

Autoclave at - C, - psi, - minutes for medical waste and unused media

PRESSURE

Autoclave

what is used to raise the temperature, not to kill the organisms

T

Autoclave (t/f)

PRIONS are not killed by autoclave

B. stearothermophilus (every week), incubated at 56 °C

Indicator of Autoclave

56 °C

Indicator of Autoclave

B. stearothermophilus (every week), incubated at -

TYNDALLIZATION & INSPISSATION

Characterized as DISCONTINUOUS/ FRACTIONAL/ INTERMITTENT sterilization

TYNDALLIZATION

Uses flowing steam

Arnold Sterilizer

- The equipment used for Tyndallization is