(P) Lec 3.1: Bacterial Pathogenesis and Epidemiology, Antimicrobials and Mechanism of Bacterial Resistance, and Indigenous Microbial Flora Flashcards
Chapter 2 of Mahon's
T or F: There are more microorganisms than humans.
True the fire
T or F: Microorganism-human encounters are inevitable.
True the fire ulit
The mechanism of exposure depends on _____
Person’s activity/behavior
Harmless microorganisms that inhabit the human body in large numbers
Pathogen
Competes with potential pathogens for resources and attachment sites
Pathogen
This aids in the digestion and nutrient absorption
Vitamin K
What are the sterile body parts?
Blood
Lungs
Brain
Serous Fluids (pericardial, peritoneal, and pleural)
What does sterile mean?
No microorganisms should be present.
What happens if there are microorganisms present in supposedly sterile body parts?
Sepsis
They are commonly found on or in body sites of healthy persons and are homegrown/native.
Indigenous Microbial Flora
They colonize an area for months or years and are life-long members of the community.
Resident Microbial Flora
They are present at a site temporarily (passing by daw sabi ni Sir Mabaggu) and are eliminated by host’s inherent immune defenses or by competition with resident biota.
Transient Microbial Flora
What are the factors that determine the composition of the usual microbial flora?
- Nutritional and Environmental Factors
- Resistance to bile, lysozyme, or fatty acids
- pH
- Low Oxidation-Reduction Potential
Factors that determine the composition of the usual microbial flora
- More organisms inhabit moist areas than dry areas. (eg. diphtheroids & non-pathogenic corynebacterium)
Nutritional and Environmental Factors
Factors that determine the composition of the usual microbial flora
- Lipids and fatty acids are bactericidal to most bacteria.
- Propionibacterium spp. (ex. P. acne – causative agent of pimples)
They are able to breakdown the skin lipids to fatty acids.
Resistance to bile, lysozyme, or fatty acids
Factors that determine the composition of the usual microbial flora
- Female genital tract microbiota depends on the pH of that environment (4.0-5.0)
- Many bacteria do not survive at this extreme pH range (pero sabi ni Sir Mabaggu kaya daw ng Lactobacillus so maniwala na lang kayo hehe)
pH
Factors that determine the composition of the usual microbial flora
What is the usual pH of the female genital tract microbiota?
4.0 to 5.0
Factors that determine the composition of the usual microbial flora
- This environment supports only organisms capable of fermentation. (eg. gingival crevices - bacteroides and fusobacterium, obligate anaerobes)
Low Oxidation-Reduction Potential
Composition of Microbial Biota
Has numerous mechanisms to prevent infection and protect underlying tissue.
Skin
Composition of Microbial Biota
This includes:
* physical separation
* presence of fatty acids
* excretion of lysozyme (sweat glands)
* desquamation (skin)
Skin
Composition of Microbial Biota (Skin)
Armpit, groin, axillae, and between toes
Aerobic Diphtheroids – Corynebacterium spp
Composition of Microbial Biota (Skin)
Hair Follicles, sweat and sebaceous gland
Staphylococcus epidermidis and Propionibacterium spp.
Composition of Microbial Biota
The oral cavity — contains a large number of bacteria, with Streptococcus being the predominant genus
Upper Respiratory Tract
Composition of Microbial Biota (URT)
Mouth
Gram (-) anaerobes
Composition of Microbial Biota (URT)
Nose
Diplococci and diphtheroids
Composition of Microbial Biota (URT)
Oropharynx
Mixture of streptococci (mitis, mutans, milleri, sanguinis, salivarius, pneumoniae)
Composition of Microbial Biota
- Comprises the esophagus, stomach, small intestine, and colon
- Less microbial population in esophagus (mostly transient)
Gastrointestinal Tract
Composition of Microbial Biota (GI Tract)
Stomach
Streptococcus
Enterococcus
Prevotella
Opportunistic Helicobacter pylori
Composition of Microbial Biota (GI Tract)
Colon
(contains 70% of all the microbes in the body; these microbes (on the right) outnumber g(-) bacteria in the large intestine)
Obligate anaerobes (Bacteroides, Clostridium, Prevotella, Porphyromonas)
Composition of Microbial Biota
Kidney, bladder, cervix, and fallopian tube are?
Normally Sterile
Composition of Microbial Biota (Genitourinary Tract)
Vaginal biota (before puberty)
Yeasts
Gram (-) bacilli
Gram (+) cocci
Composition of Microbial Biota (Genitourinary Tract)
Vaginal biota (childbearing years)
Lactobacilli
Anaerobic gram (-) bacilli
Gram (+) cocci
Composition of Microbial Biota
Vagina epithelial cells maintain a ____ pH, which encourages the colonization of listed bacteria.
Low
Some organisms that make up the microbial biota live off the _____
Host’s nutrients
in most cases, they provide some benefit to the host, creating a ____ relationship.
Symbiotic
Activation of Immune System
- Secretion of metabolic products
- Prevention of pathogen adhesion
Recognized to cause disease in healthy immunocompetent individuals a high percentage of the time
Yersinia pestis and Bacillus anthracis
True Pathogens
Causes disease when their habitat is altered or when the host’s immune system is compromised
Opportunists
Can be found in traumatized areas (accidental/surgical) and may reach sterile or other parts where these organisms are not part of the microbial biota
Opportunists
Name the organisms (sorry, I’m not a sadist)
Foreign bodies (catheters, shunts, prosthetic heart valves)
- Staphylococcus epidermidis
- Propionibacterium acnes
- Viridans streptococci
- Serratia marcescens
- Pseudomonas aeruginosa
- Aspergillus spp
- Candida albicans
Name the organisms (sorry, I’m not a sadist)
Alcoholism
- Streptococcus pneumoniae
- Klebsiella pneumoniae
Name the organisms (sorry, I’m not a sadist)
Burns
- Pseudomonas aeruginosa
- Acinetobacter baumannii-calcoaceticus complex (drug-resistant)
- Staphylococcus aureus
Name the organisms (sorry, I’m not a sadist)
Hematoproliferative disorders
- Cryptococcus neoformans
- Varicella-zoster virus
Name the organisms (sorry, I’m not a sadist)
Cystic Fibrosis
- Pseudomonas aeruginosa
- Burkholderia cepacia
Name the organisms (sorry, I’m not a sadist)
Immunosuppresion (drugs, congenital disease)
- Candida albicans
- Pneumocystis jirovecii
- Herpes simplex virus
- Aspergillus spp.
- Diphtheroids (Corynebacterium spp.)
- Cytomegalovirus
- Staphylococcus spp.
- Pseudomonas spp.