Microbiology microbes and diseases
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- Diseases of Staphylococcus aureus:
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**food poisoning, skin diseases, systemic diseases (TSS, bacteremia, heart, lung, and bone infections)
**diseases spread by fomites and direct contact - S. aureus virulence factors and Rx:
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*Coagulase; triggers blood clotting
*Capsules, hyaluronidase, staphylokinase, betalactamases (destroy penicillins)
*Toxins: various, including TSS toxin, exfoliatin, and enterotoxins (heat stable)
*95% resistant to penicillin, but now many resistant to methicillin, and now vancomycin, leaving ? - Streptococci: G+ cocci
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aerotolerant anaerobes, catalase negative, grow in chains and pairs.
Group A strep: S. pyogenes
Group B strep: S. agalactiae - Group A strep: S. pyogenes
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pharyngitis, scarlet fever, pyoderma, erysipelas, TSS, necrotizing fasciitis
Sequela: rheumatic fever and glomerulonephritis - Group B strep: S. agalactiae
- infects newborns during birth, various illnesses.
- S. pyogenes, Group A:
- pharyngitis (strep throat), scarlet fever, skin diseases
- S. pneumoniae:
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lung infections (pneumoniae), meningitis, middle ear infections;
major virulence factor is capsule; occurs in pairs=diplococci. - S. agalactiae:
- vaginal microbiota, cause newborn septicemia and meningitis
- Viridians group:
- alpha hemolytic; common in throat and mouth, S.mutans=tooth decay
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Enterococcus:
E. faecalis and E. faecium: - normal microbiota in GI tract, antibiotic resistant, cause of endogenous infections.
- Neisseria: Gram - cocci
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N. meningitis and N. gonorrhoeae
**coffee bean shaped in pairs
**pyogenic - N. gonorrhoeae
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cause of gonorrhea
virulence factors: capsule, fimbriae, survival in neutrophils
*males: painful discharge from urethra
*females: often asymptomatic; otherwise, urethritis, PID, arthritis.
*eye infection of newborns
*no long term immunity - N. meningitis
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cause of bacterial meningitis
capsule protects cells during phagocytosis
present as normal microbiota in 40% of population
trasmitted by droplets, close contact
infection of meninges, sore throat, high fever, headache, stiff neck, vomiting, convulsions - serology
- use of antibodies to identify particular antigenic molecules on cell surfaces
- O antigen
- repeating sugar group on LPS
- H antigen
- flagellar protein
- K antigen
- capsule antigen around cell
- Klebsiella pneumoniae
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various opportunistic infections including wound infections, pneumonia
**capsule is the major virulence factor - Proteus
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changes shape and flagella between liquid and solid media; common cause of UTIs.
**produces urease - Enterobacter aerogenes
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coliform; GI tract and environmental
wound infections - Salmonella
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present in eggs, poultry, on animals such as reptiles.
large dose results in food poisoning; diarrhea, fever, etc. - Salmonella typhi
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typhoid fever. spread through body. gall bladder as reservoir.
importance of clean water and sewage treatment. - Shigella
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S.sonnei (most common)and
S. dysenteriae (most serious); cause shigellosis.
*very small infectious dose, personal hygiene importantin prevention.
*infection damages intestinal lining, cells pass directly from cell to cell; cramps, diarrhea, bloody stools.
S. dysenteriae produces shiga toxin which inhibits protein synthesis, increases damage. - Yersinia
- Y. pestis is cause of plague, other species cause food-borne infections.
- Plague: 3 cycles
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sylvan, urban, and human
**endemic in sylvan cycle; mixing of woodland and urban rodents brings urban cycle; fleas jump from dying rats to humans.
Infection leads to large swollen lymph nodes: buboes.
Bubonic plague: high fever
Septicemic plague: with DIC, bruising (black death)
Pneumonic: coughed out and spread human to human, 100% mortality - Pasteurella multocida
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small Gram - rod
common in animals, people get it by bites, scratches.
inflammation, swollen nodes near site of infection - Haemophilus
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H.influenzae: mostly respiratory infections and meningitis and epiglottis in very young.
H.ducreyi: STD chancroid; visible and painful in men. - Brucella
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infection from contact with livestock, fluids including dairy.
Undulant fever: fever that goes up and down; several other names including Bang's disease. -
Bordetella:
B. pertussis -
cause of whooping cough
infects trachea, several toxins.
disease in stages:
incubation, catarrhal, paroxysmal - Pseudomonas aeruginosa
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G- aerobic rod
*most dangerous Pseudomonas
capable of causing disease anywhere in body
Burn patients and cystic fibrosis patients most vulnerable
Cause of swimmer's ear, hot tub infections
**resistant to most antibiotics and disinfectants -
Francisella:
F. tularensis -
cause of tularemia
also called rabbit fever, tick fever, deerfly fever.
Chills, fever, malaise, swollen nodes -
Legionella:
L. pneumophila -
very common in aquatic environments: ponds, cooling towers, hotwater heaters, showers.
most dangerous as opportunistic pneumonia, inhalation
"pontiac fever": mild form of disease. - Bacteroides
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anaerobic gram- rod
live in diff. parts of body, especially GI tract; also in mouth, genito-urinary tract.
trauma to these areas leads to polymicrobic infections. - Member of the herpes virus family:
- HSV 1 and 2, Variella zoster(VZV), Epstein Barr (EBV), and cytomegalovirus (CMV)
- Herpes simplex 1 and 2:
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HHV 1: above the waist
typically oral, cold sores, flu-like symptoms.
HHV 2: genital, STD & neonatal. Painful, contagious sores on genitals, overlaps with HHV1. - Varicella zoster
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Varicella: chicken pox
Zoster: shingles - Cytomegalovirus
- CMV (HHV5): infection results in enlarged cells.
- Epstein-Barr virus
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cause of infectious mononucleosis.
infects B-cells and salivary glands.
sore throat, swollen glands and spleen
long lasting fatigue - Hepatitis
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inflammation of the liver
damage results in accumulation of bilirubin
results in yellow color=jaundice - Hepatitis B
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DNA virus:"hepadnavirus"
released from live cells, so high numbers in body fluids.
blood of infected person is highly contagious
large amounts of empty capsids ties up antibodies. - Hepatitis A
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small RNA virus:"picornavirus"
transmitted by fecal-oral route. incubation for 1 month, followed by fever, nausea, anorexia, jaundice.
T cells attack infected liver cells.
no chronic infections, patients recover. - Hepatitis C
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RNA virus, diff. group: "flavivirus"
causes chronic infections.
transmission like HepB: blood, sex, transplants.
often mild w/few symptoms until damage
long period bet/n infection and damage -
Arkansas Arboviruses:
Encephalitis -
spread by mosquitoes;
Eastern Equine enceph., togavirus.
St. Louis enceph., West Nile virus, flavivirus. - Mycoplasma
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unusual properties
very small, pleomorphic (cocci to filaments)
Have no cell walls, but have sterols in their membranes - M. pneumoniae
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attaches to epithelial cells, kills them
Buildup of mucus, other infections.
Fever, malaise, sore throat, etc. Walking pneumonia
No cell wall, so can't treat with penicillins! - Ureaplasma urealyticum
- sexually transmitted, cause of urethritis
- Rickettsiae
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gram negative, very small, obilgate parasites
most spread by vectors
Damage to capillaries produces spots, rashes - R. rickettsii
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Rocky mountain spotted fever
spread by tick bite - R. prowazekii
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epidemic typhus
vector is the human louse - R. typhi
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murine/endemic typhus
vector is the flea - Ehrlichia chaffeensis
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spread by lone star tick and dog tick
infects leukocytes rather than endothelial cells. - Chlamydia
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cell wall and outer membrane, but no peptidoglycan.
spread directly rather than by vectors.
Two stage life cycle:
elementary body: tiny and inert. Spore-like~dormant and resistant. Infectious~form that moves between cells.
Reticulate Body: metabolically active, reproduce inside host cells. - C. trachomatis
- infects cells of mucous membranes, conjunctiva. Mostly eye and STD.
- Trachoma
- leading cause of non-traumatic blindness. infection of conjunctiva causes scarring, turning in of eyelashes which scratch cornea.
- Non-gonococcal urethritis
- chlamydia infections are the most common STD, but even more are infected and asymptomatic.
- Lymphogranuloma venereum
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lymph nodes in genital region become enlarged (buboes), may even rupture.
blocked lymph ducts lead to genital elephantiasis. - Chlamydia pneumoniae
- cause of bronchitis, sinusitis, pneumonia
- Chlamydia psittaci
- cause of ornithosis
- Spirochetes
- have internal flagella in bundles called axial filaments; corkscrew through liquid.
- Treponema pallidum
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cause of syphilis,STD
hard painless genital ulcer; long incubation; ulcer disappears, spirochete spreads, causes systemic disease (rash, fever); either goes away, comes back, or tertiary syphilis in which gummas form, serious stage. - Borrelia burgdorferi
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cause of Lyme disease
spread by deer tick
slow developing, fever, bulls-eye rash; arthritis and heart or CNS involvement - Borrelia recurrentis
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cause of relapsing fever
spread by lice or ticks - Leptospira interrogans
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cause of leptospirosis
from contact with animal fluids, esp. urine.
infects liver and kidneys - Vibrio cholera
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gram- curved rod
toxin-mediated severe diarrhea - Campylobacter jejuni
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number one cause of bacterial gastroenteritis; zoonotic.
Food-borne disease, most retail chickens are contaminated. - Helicobacter pylori
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cause of ulcers and gastritis
unusual b/c can live in stomach
produces urease enzyme
correlated w/stomach cancer - Aspergillus
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aspergillosis
very common in soil, plant materials. - Candida
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candidiasis
cause of vaginal infections, diaper rash, thrush.
capable of infecting any part of the body - Cryptococcus neoformans
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inhalation of spores
predilection for CNS - Pneumocystitis carinii
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fungus
most cases associated w/AIDS
serious lung infections: PCP - Balantidium coli
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present in hog intestines
source: contaminated water
disease: attack of GI tract - Entamoeba histolytica
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fecal-oral transmission
asymptomatic to severe diarrhea - Acanthameoba and Naegleria
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natural water or through eye (Acanthamoeba)
brain infections; rare, fatal (Naegleria) - Trypanosoma
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cause of african sleeping sickness, spread by tsetse fly. Infection of CNS, causes coma.
cause of Chagas disease, spread by reduviid bug: eventually damages heart tissue. - Leishmania
- causes leishmaniasis, spread by sandfly
- Toxoplasma
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kills fetus
part of life cycle involves cats, so pregnant women must stay away from litter box - Cryptosporidium
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primarily livestock and poultry, acquired fecal-oral through food or contaminated water.
diarrhea, but systemic spread as well.