MLS 334 Exam 1

Microbiology

specialized area of biology that encompasses tiny life forms that are microscopic

Microscopic Organisms

includes microbes, bugs, germs, and microorganisms

Branches of Microbiology

bacteriology

mycology

parasitology

virology

phycology

physiology

taxonomy

Taxonomy

the orderly classification and grouping of organisms

Classification

arrangement of organisms into groups

Nomenclature

assigning names to various taxonomic rankings for each microbial species

Identification

discovering and recording the traits of organisms so they can be put into the taxonomic scheme

Categories of Classification

Genotype (genetic makeup) or Phenotype (media, gram stain, morphology, biochemical characteristics, antimicrobial resistance patterns)

Hierarchical Classification

Largest-Smallest

Domain

Kingdom

Phylum

Class

Order

Family

Genus

Species

Rules of Nomenclature

1. Use binary names (genus and species)

2. Capitalize the genus but not the species

3. Italicize the if types or underline if handwritted

4. Abbreviate initial capital letter and follow by species

5. Lowercase and non-italic for common name

Public Health

Focused on examining the health needs of entire populations with the goal of preventing health problems.

Infection

invasion and multiplication of microorganisms within a host

Carrier

person may harbor a pathogen that can be transmitted to others without eliciting disease themselves

Colonization

bacteria on our body surface that does not oleic an immune response or disease

Normal Flora

Organisms that exist in a symbiotic relationship with the host

Classification of Infectious Diseases

1. Microbiological (pathogen or causative agent)

2. Clinical (clinical manifestation - signs and symptoms)

3. Epidemiological (transmission and reservoir)

Chain of Infection

pathogen, reservoir, portal of exit, mode of transmission, portal of entry, susceptible host

Infectious Disease Periods

1. Incubation (no signs or symptoms)

2. Prodromal (vague, general symptoms)

2. Illness (most severe signs and symptoms)

3. Decline (declining signs and symptoms)

4. Convalescence (no signs or symptoms)

Individual Disease Prevention Measures

hand hygiene, food and water safety, condom use

Community Disease Prevention Measures

sanitation, water safety, blood-donor screening, isolation and quarantine

Lab Safety Organizations

OSHA (Occupational Safety and Health Administration)

EPA (Environmental Protection Agency)

CDC (Center for Disease Control and Prevention)

JACHO (Joint Commission for Accred of Healthcare Orgs)

CLSI (Clinical Laboratory Standards Institute)

WHO (World Health Organization)

Exposure Control Plan

OSHA designed to protect employees against exposure to bloodborne pathogens - reviewed by employees annually

Standard Precautions

A strict form of infection control that is based on the assumption that all blood and other body fluids are infectious.

Droplet Precautions

close respiratory contact or exposure of mucus membranes/respiratory secretions

Airborne Precautions

Infectious Agents that can remain airborne for long periods of time and long distances

Contact Precautions

direct or indirect contact with patient or environment

Workplace Safety Precautions

practices done to reduce likelihood of an exposure to infectious agents (ex: no mouth pipetting, eating or drinking, disinfect surfaces, handwashing, disposal of sharps correctly)

Personal Protective Equipment (PPE)

Protective equipment that blocks exposure to a pathogen or a hazardous material.

Biological Risk Assessment for Microbiologists

1. Processing patient specimens

2. handling actively growing cultures

Risk Group 1

No or low individual and community risk

Risk Group 2

Moderate individual risk, low community risk

Risk Group 3

High individual risk, low community risk

Risk Group 4

High individual and community risk

Biological Safety

-engineering control

-protects workers from aerosolized transmission of organism

-4 levels

BSL-1

-no potential for exposure to pathogenic material or biohazards

-lab work conducted on open bench

BSL-2

specific training, limited lab access, immunizations

BSL-3

negative air pressure due to exotic pathogens that are potentially aerosolized or inhales

BSL-4

class III BSC, positive protective suit, isolated lab

Chemical inventory

A list of every product used in the lab that contains chemicals - updated annually

Symbiosis

two different organisms living together, usually advantageous to both

Commensalism

A relationship between two organisms in which one organism benefits and the other is unaffected

Mutualism

both microorganism and host benefit

Parasitism

microorganism benefits but host is harmed

Normal Flora (indigenous)

microorganisms that are normally present in a specific site

Carrier State

person harbors organism but does not show any signs of the disease, may pass it on

Infection

pathogen penetrates host, enters tissue, multiplies

Infectious Disease

A disease that is caused by a pathogen, causes damage/disruption to the host, and that can be spread from one individual to another.

Transiet Microbes

microbes that occupy the body for a SHORT amount of time

Resident Microbes

microbes that have established residence (long-term)

Microbial Flora Composition

-nutritional factors

-antibacterial substances (fatty acids, lysozyme, bile)

-environment (gaseous atmosphere, low pH, moist or dry)

Sites that contain normal flora

-skin and mucous membranes

-upper respiratory tract

-GI tract

-outer opening of urethra

-external genitalia

-vagina

-external ear and canal

-external eye

Sterile Sites

internal organs and tissue (heart, liver, kidneys, brain, etc.)

blood, urine (in bladder, ureters, and kidneys), and CSF

Skin Flora

-on the skin surface, hair follicles, and apocrine sweat glands

-colonize the skin surface to prevent pathogens from colonizing

Types of Microorganisms Found on the Skin

Candida spp.

Micrococcus spp.

Staphylococcus spp.

Clostridium spp.

Propionibacterium spp.

Diphtheroids

Mouth Flora

-supports anaerobic growth (low redox potential)

-on the buccal mucosa and tooth surface

Microorganism Found in the Mouth

Streptococcus mitis

Streptococcus sanguis

Streptococcus salivrius

Streptococcus mutans

Respiratory Tract Flora

only in the upper respiratory tract (lower is considered sterile)

Microorganism in the Nose and Nasopharynx

Staphylococcus aureus

Staphylococcus epidermidis

Diphtheroids

Haemophilus parainfluenzae

Streptococcus spp.

Microorganisms in the Oropharynx

Diphtheroids

Streptococcus mitis

Streptococcus sanguis

Streptococcus salivrius

Streptococcus mutans

Streptococcus milleri

Staphlyococcus aureus

Staphylococcus epidermidis

GI Flora

-located in the esophagus, stomach, small intestine, and colon

-environment favors anaerobes

-beneficial relationship (ferment waste to generate vitamins and contain digestive enzymes)

-stomach îs normally sterile (acidic pH)

Microorganisms Found in the GI Tract

Bacteroides spp.

Clostridium spp.

Enterobacteriaceae

Eubacterium spp.

Fusobacterium spp.

Peptostertococcus spp.

Peptococcus spp.

Staphylococcus aureus

Enterococcus spp.

Microogranisms Found in the Genitourinary Tract

Lactobacillus spp.

Bacteroides spp.

Clostridium spp.

Peptostreptococcus spp.

Staphylococcus aureus

Staphylococcus epidermidis

Enterococcus spp.

Diphtheroids

Microbial Flora Role in Infectious Disease

-opportunistic infections (host environment change or weakened immune system)

-trauma

-immunosuppressed host

Microbial Flora Infectious Disease Protection

prime immune system and block colonization of pathogens

Pathogenesis

development of disease

Pathogenicity

ability of a microorganism to cause disease

Opportunistic Pathogen

causes disease only in the absence of normal host resistance

True Pathogen

capable of causing disease in healthy persons with normal immune defenses

Iatrogenic Infection

infections from medical treatments or procedures

Virulence

ability for a microorganism to cause disease

Virulence Factors

enhance ability to cause disease and includes capsules, toxins, adhesive fimbriae, ability to survive intracellularly

Host Resistance

physical barriers (intact skin)

cleansing mechanisms (tears, urine cilia)

low pH (acidic in stomach and vagina)

antimicrobial substances (fatty acids on skin, HCl in stomach, lysosomes, immune proteins)

indigenous microbial flora

phagocytosis

inflammation (accumulation of phagocytic cells and release of mediators)

digestion of foreign particles by enzymes

Phagocytosis

-primary mechanism against extracellular bacteria (polymorphonuclear cells and macrophages)

not effective for intracellular pathogens

Diapedesis

movement of WBCs from blood vessels into tissues

Chemotaxis

chemically stimulated movement of phagocytes to a site of damage

Steps of Phagocytosis

1. Attachment (organism to phagocyte)

2. ingestion (enclose in phagosome, fuse with lysosomes, degranulation)

3. Killing (increased metabolic activity and glycolysis, release enzymes)

Mechanisms to Resist Phagocytosis

capsules

Immune System

how the body protects itself from disease

Innate Immunity

natural, nonspecific (physical and chemical barriers, phagocytosis)

Adaptive Immunity

specific (b and t lymphocytes)

passive acquired immunity

mom passes antibodies to baby

active acquired immunity

response to antigen (disease or vaccination)

Humoral Immunity

initiated by antibodies/immunoglobulins

Classes of Antibodies

IgG, IgM, IgA, IgD, IgE (decreased %)

Primary Antibody Response

IgM appears first, followed by IgG

Secondary Antibody Response

rapid increase in IgG

Cell-Mediated Immunity

protects against intracellular pathogens (t-helper CD4+ and cytotoxic t-cells CD8+)

Sign

objective evidence of disease from an observed (ex: fever)

Symptom

subjective evidence of a disease sensed by patient such as pain or a headache

Laboratory Signs of Infection

elevated WBC (bacterial = neutrophils and viral = lymphocytes)

elevated ESR and C-reactive protein

-high lactic acid may indicate sepsis

Prokaryotic Cell

-no membrane bound nucleus or organelles

-ribosomes (RNA and protein) found free in cytoplasm and attached to cytoplasmic membrane

-70S ribosome complex (dissociate into 50S and 30S with centrifugation)

-Endospores to increase survival

Bacteria cell envelope includes...

plasma membrane and cell wall

Plasma Membrane (Cell Membrane)

-phospholipid bilayer (with embedded proteins)

-functions as an osmotic barrier

Cell Wall Categories

-gram positive

-gram negative

-acid-fast

-absence/none

Gram Positive Cell Wall Structure

-one major layer

-composed to peptidoglycan, teichoic acid, lipoteichoic acid, mycelia acids, and polysaccharides

-no outer membrane

-narrow periplasmic space

-penetrable to molecules

Peptidoglycan (Murein)

the polymer of alternating N-acetylmuramic acid (NAM) and N-acetylglucosamine (NAG) and pentapeptide (5 amino acids) subunits linked together by peptide chains; a major constituent of bacterial cell walls

Peptidoglycan Function

prevents osmotic lysis

Teichoic Acid Function

cell wall strength

Surface Protein Function

enzymes and adhesions

Periplasm Function

nutrient breakdown