Bacteriology Section Flashcards

Terms Definitions
attachment-effacement lesions
EPEC
 
 
 
 
 
Antimicrobials that target topoisomerases
 
 
 
 
 
Fluoroquinolones
gas gangrene
Clostridium perfringens
Hemophilus parainfluenzae
causes endocarditis
 
 
 
 
 
Major Streptococcus species
 
Streptococcus pyogenes
Streptococcus equi ssp equi
Streptococcus equi ssp. zooepidemicus
Streptococcus canis
Streptococcus agalactiae
Streptococcus suis
Enterococcus spp
Streptococcus pneumoniae
Infection
Microbes invade tissues
"stacked bricks"
enteroaggregative E. coli
medusa-head colony appearance
Bacillus anthracis
 
 
 
 
 
Chloramphenicol, Florfenicol
Broad-spectrum
Bacteriostatic by inhibiting protein synthesis (ribosomes)
Most resistace in plasmid mediated chloramphenicol acetyltransferases
 
 
 
 
 
Treatment for Actinomycosis
 
 
 
Susceptibility: Trimethoprim/sulfa, penicillin/ampicillin (not for L-forms), tetracyclines
 
Resistance: aminoglycosides or quinolones (anaerobes!)
bacillus
gram +ve rode aerobic
morexella
gram -ve cocci aerobic
Where is pseudomonas found?
Soil
First broad spectrum antibiotic
Chlortetracycline
genus Corynebacterium
pallisade (chinese-letter) appearance; uneven, metachromatic granules
Shiga-like toxin
Enterohemorrhagic Escherichia coli (EHEC)
What are plasmids?
o Extra-chromosomal DNAo Replicate autonomouslyo Unique features: enzymes that protect v. toxins, heavy metals; antibiotic resistence genes (beta-lactimase snips PCN)
 
 
 
 
 
Rhodococcus equi
Gram-positive coccobacillus
Occurs in soil, manure, + the intestine of mammals and birds
Foal intestine serves as incubator
Acquired by inhalation of dust, ingestion, umbilicus?

No diff in # of orgs on prob farms vs. okay farms because problem farm strain has plasmid containing virulence factor
Sulfonamides
analogs of p-aminobenzoicacid (PABA). Interefere with microbial growth by competitively inhib incorp of PABA into folic acid. Folic acid req as a coenzyme to make bact DNA.
cytotoxin
diphtheria toxin which inhibits protein synthesis
Optimal growth temperature for mesophiles?
20-40C
Association, Isolation, Reproduction and Reisolation
Koch's postulates
altered target site
an bacterial antibiotic-resistance mechanism; ribosome site alteration via modification of structure of 50S and 30S ribosomes and cell wall site alteration, i.e. vancomycin-resistant bacteria replace the D-alanine with a D-lactate
bacillus cereus
highly virulent; produce enterotoxins; common food sources: fried rice, milk, meat, veg., fish
Salmonella enterica
gram-negative rod, lactose negative; hydrogen sulfide positive; motile; live in intestines of both warm and cold-blooded animals; disease- acute gastroenteritis, if in the blood, enteric fever; enterotoxin- causes watery diarrhea, cytotoxin- inhibits protein synthesis, causing diarrhea and necrosis
nosocomial cause of typical pneumoniae
Pseudomonas aeruginosa
6 categories of infectious disease
1.communicable disease2.contagious3.iatrogenic- originates from medical intervention4.nosocomial- acquired in health care facility (place-relationship)5.opportunistic (immunocompromised)6. subclinical
important agent of UTI in men
Proteus
sand-paper rash
scarlet fever; group A strep
Salmonella typhimurium
Cows: watery diarrheaHorses: most common salmonellosis in horses; acute or chornic diarrheaPigs: Enteritis
 
 
 
 
 
Methicillin resistance in MRSA and MRSP

mecA resistance gene (penicillin binding protein with affinity to B-lactams and methicillin)
MRSA contains staphylococcal cassette chromosome
Mobile genetic element wth integrated copies of plasmids
No phage-related genes, but mobility due to two recombinases
Flagellar Placement
Monotrichous (one end), lophotrichous (many on one end), peritrichous (all over), amphitrichous (one at each end)
Endospores
resistant forms of organisms. ex) bacillus and clostridium. can resist enviro conditions. posses a nucleoid, ribosomes, and energy gen cmpts. they are dormant when conditions are favorable.
epidemic:
any infectious disease that develops and spreads rapidly to many people
Fimbriae
many bacteria can express distinct types which allows for adaptation to new environments and greater diversity for different host surfaces
Microorganisms w/ smaller IDs have ??greater/lesser?? virulence
Greater
grow in presence of oxygen/require oxygen free conditions
aerobic/anaerobic
disease of infection resulting from activity of the veterinarian
iatrogenic
virulence factors of Enterococcus
cytolysin; aggregation substance; extracellular surface protein
S. pneumoniae (50% of cases in adults); N. gonorrhea (60% of cases 12-20); Listeria monocytogenes (neonates, pregnant women)
Meningitis
formation of tubercle, breaks down to release organisms, bacteremia, dissemination
tuberculosis
Rickettsia mosseri
endemic typhus, more popular in U.S.
C. Diptheriae is tx with
Antitoxin + erythromycin
Yersinia pseudotuberculosis
Birds, rodents: similar to bubonic plague but transmitted by ingesting droppings. Lesions on intestine/mesenteric ln.
 
 
 
 
 
Enterococcus spp
 
 
Very close to strep, but survive well in GI
a-hemolytic (so not usually pyogenic)
endocarditis and 10-15% canine urinary tract infections (UTI
borrelia
like trpanoma and leptospira gram -ve spirochetes
Transcription
RNA poly binds to promoter regionDNA strands apartsynthesis of RNA terminator reachedregulatory proteins bind to promoter region for induction or repression
Bacterial subunit vaccines
Neisseria Meningitidis- used for military and college kidsStreptococcus pneumoniae- capsular used for high risk patients and elderly only has K antigen. Capsular + pneumolysin used for kids has K ant and virulence factorBordetella pertussis- whooping cough. two virulence factors. kids. Bacillus anthracis- anthrax. consists of a number of antigens. Used for military
enterotoxin
cholera toxin and enterotoxins of E coli that cause diarrhea and/or vomiting
Examples of adhesins:
fimbriae, portions of glycocalyx, lipotechoic acids, outer membrane proteins
zoonosis?
an infection indigenous to animals but naturally transmissible to humans
Sepsis
Growth of microorganisms in blood and other tissue
host or hosts which infectious agents depend on for survival
reservoir
Brudzinski's sign
passively flex leg and other leg flexes reflexively; meningitis
causative agents of chronic bronchitis
Hib; Streptococcus aureus; Aeruginosa
listeria monocytogenes
associated with meat; human GI flora, soil, herd animals; 3 virulence factors- internalin, listeriolysin-O, actA; common diseases- gastroenteritis, with high likelihood of transmission in utero which leads to fetal death early in pregnancy, encephalitis and meningitis in late pregnancy, and meningitis in immunocompromised individuals
EPEC; ETEC; Vibrio cholera
causative agents of watery, non-inflammatory diarrhea
What are pilli or fimbria?
o Glycoproteino (1) Mediate attachment to cellso (2) Mediate attachment for sex
What is Acinetobacter?
- Like surfaces that are constantly wet- Preference for UR tract- Usually infections in immunocompromised and hospitalized people- UTI, pnemonia, soft tissue
 
 
 
 
 
Erysipelas in non-pigs
 
Turkeys, geese and other birds (acute septicemia, vegetative endocarditis, arthritis)
Sheep (polyarthritis
Dogs (vegetative endocarditis, bacteremia)
Marine mammals (serious, fatal septicemia
Humans (Erysipeloid is localized cellulitis)
Carbapenems
B lactams with carbon sub for sulfer. Broadest spectrum of all B lactams. Ex) Imipenem 


Gram stain
Since the gram pos has peptidoglycan the CV1 complex is trapped. App of safranin results in gram pos being purple and gram neg being pink or red.
Transformation
naked DNA derived from one cell is taken up by another cell and recombines with the genome. Ability to incorporate DNA in this manner is termed competency. occurs during log phase of growth.
Secondary infection:
An infection in a host already infected with another pathogen, often caused by opportunistic pathogens in immunodeficient or immunosuppressed hosts.
endogenous infections
occur when normal biota is introduced into a previously sterile site
What are some chronic infxns?
herpes simplex
herpes zoster
hep B
AIDS
Epstein-Barr
What is a symptom?
subjective feelings that are verbalized by the patient
Describe drug inactivation mechanism
beta-lactamases inactive PCNs and cephalosporins (staph aureus and PPNG)
immunity not intrinsically affected by prior antigen contact
innate resistance/ immunity
CELL WALL DEFICIENT FORMS OF GRAM POSITIVE OR NEGATIVE BACTERIA
l FORMS
starts off as purpulous lesion
fish finger, whale finger; erysipeloid
abrupt onset; fever; malaise; loin pain; edema; hematuria; proteinuria; oliguria; usually seen in kids 1-5 y.o.; usually secondary to a GAS infection
symptoms of acute glomerulonephritis
HiB primarily causes what three diseases in unvaccinated children?
1. Septicemia2. Meningitis3. Epiglottitis
What is the mechanism of sepsis?
- Inflammation, coagulation intended to isolate pathogen. In sepsis, the regulators aren’t working, so there is over-inflammation and coagulation of endothelial cells, which then triggers a second wave of the same, as well as the release of tissue factor, releasing thrombin, which causes clotting- Low APC: Activated Protein C is a controller of inflammation and a supporter of fibrinolysis. When it’s low, you get tiny little clots all over, causing blockage and tissue/organ death
What are exotoxins?
- When treated with formaldehyde, acid or heat, they form toxoids (lose toxicity, retain antigenicity) – vaccines - Spreading factors- Hyaluronidase snips a certain point so organism can move into new space- DNAase breaks through viscous DNA- Streptokinase breaks through post-derived fibrin clots so bacteria can escape wound site- Membrane disrupting - Hemolysins break open and spill RBCs - Leukocydins- Protein synthesis inhibition - Diptheria- Activation of second messenger - Cholera, E. coli ST/LT- Cholera produces choeragin which causes unregulated production of cAMP, flooding enteric cells, causing chloride release, ion flush, secretory diarrhea, massive dehydration- Proteases - Clip specific proteins, especially synaptobrevins (which are responsible for NT release and inhibition)- Tetanus/botulism- Immune response activators (superantigens) - Presence hyperstimulates cytokine release - Toxic shock syndrome- Type III secretion system – like needle injection
Toxins: Endotoxins
LPS in G neg bacteriaactive portion is Lipid A, induces fever, initiate complement cascade, activate B lymphocytes, stim prod of tumor necrosis factor, interleukin 1, and prostaglandins, can cause fever, hypotension, shock, and death
Infectious disease
Disruption of a tissue or organ caused by microbes and their products
What is Equine metrits (CEM)?
Caused by Hemophilus equigenitalis

Equine venereal disease
Male asymptomatic
Female exhibit profuse vulvar discharge
What are virulence factors?
Any characteristics or structure of the microbe that contributes to its virulence
Describe change of drug receptors
Erythromycin alteration on 50S ribosomal binding site
PCN - alteration in binding proteins in cell wall
What is competency?
Ability to incorporate DNA in the manner of transformation
bacterial flora that may reside on an animal for a period of time, but are ultimately displaced by indigenous folora
transient flora
overproduction of target
too much enzyme to be handled by antibiotics
TSST of S. aureus
toxic shock syndrome; related to a group of enterotoxins; affects endothelial cells, causing leakage, edema, and shock; associated with tampon use; causes rash in both males and females
4 lower respiratory tract infections
1. bronchitis; 2. typical pneumonia; 3. atypical pneumonia; 4. empyema
What is N. meninigitis?
- Like ticks, serves no purpose - If it becomes systemic it can lead to death in hours- Among the leading causes of bacterial meningitis, especially in the 12-25 year old group
What are the common source sites of sepsis?
1. CNS2. Pnemonia3. Skin (cellulites, wounds)4. Appendix/intestine5. Liver6. IV catheters7. UTIs – especially in elderly30% have unidentified source of sepsis.Preceding viral infection may predispose to bacterial sepsis.
facultative anaerobe
can grow w or w out oxygen. metab fermentative and employs aerobic resp but may use anaerobic
what are the 2 super-antigens?
Staph. Aureus: mediated toxic shoch syndrom toxin -1 (TSST-1)
Strep. Pyogenes: pyrogenic exotoxin A (SPE type A)
What disease is caused by burkholderia?
Melioidosis: common in tropical region.

Similar to TB with latent period and chronic periods.

; ranges from relatively benign pulmonary infection to rapidly fatal septicemia characterized by caseous lung abcesses/nodules
What are the 2 variations of transduction?
generalized and specialized tranduction
In what situation would normal biota be harmful to the host and lead to infection?
Immunosupression such as AIDS
What is a pathogen?
Microbe whose relationship w/ its host is parasitic and results in infection and disease
formal system of naming specific species, two parts
Binomial nomenclature; Genus and Species
enteric strains of Escherichia coli
all exogenous; 6 varieties of enteric E. coli; EHEC (enterohemorrhagic E. coli) is predominant type- abrupt onset, vomiting, diarrhea
pathogenesis of GI strains of Salmonella
infect gut epithelium; digest mucosal glycocalyx; invade enterocytes, which stimulates pro-inflammatory cytokines; short-term- diarrhea, long term- ulcers
What are the general characteristics of Salmonella enterica (and subspecies)?
- Gram negative rods, unable to ferment lactose (big difference between this and e. coli), produces H2S (hydrogen sulfide positive- only in certain medias) (whereas shigella is H2S neg. and nonmotile)- Live in intestines of warm and cold blooded animals- Most are motile, like water- Classification is very complicated – more than 2400 different serotypes!o Species name, with serotype name after (Salmonella enterica typhi)- Predominantly industrialized society diseases: in mass-production, we contaminate food, food at rest., sewage contamination- Disseminated in environment via water, soil, plants, human and animal excretion (but don’t multiple, but survive here)- Food (eggs, ice-cream, mayo, meats (contim by shit), veggies, rec. drugs,) pets or water (main source of wide epi)- Usual entrance: oral ingestion
What are the genreal characterisitcs of Legionella?
L. pnemophilia- 90% of all legionella infections in humans involve this member of the legionella family, mostly serogroups 1, 3, 6- Very hardy (0-60 degrees C; pH 5-8.5; need very little O2) - Become attached to surfaces in aquatic environments and form biofilm for attachmento Biofilm then acts as protection- Naturally distributed in all sorts of water: lakes, ponds, water tanks, swimming pools (can survive chlorination), air conditioners- These are naturally parasites of aquatic ameba
PIA – polysaccaride intracellular adhesions ?
used to stick bacteria together and also to stick to RBCs
how are noncommunicable diseases acquired?
1. compromised person invaded by his or her own microbiota
2. individual has accidental contact with microbe in a non-living reservoir
What is an aerotolerant anaerobe?
Does not utilize O2, but can survive/grow to limited extent in it
1. What are bacterial endospores?
2. What is the term for the other phase of the bacterial life cycle?
3. What induces sporulation?
1. extremely resistant stage; dormant bodies
2. vegitative cell
3. environmental conditions; depletion of nutrients
What are 3 types of isolation media?
1. nutrient media
2. selective media
3. indicator media
protein synthesis is the target of what?
a target of antibiotics; second largest class of antibiotics behind cell wall synthesis inhibitors; include clindamycin, aminoglycosides, stretogramins, tetracyclines, macrolides; all take advantage of the fact that bacteria produce proteins with 70S ribosomes, inhibitors bind to either 70S ribosome of 50S or 30S subunits
C. diptheriae uses what two types of cultures?
Tellurite- (gray to black colonies)Loffler's- metachromatic VOLUTIN granules
What is the pathology of Strep pneumoniae?
- Humans are the only host- Doesn’t last long on surfaces, heat, cold, etc- Direct contact/aerosols spread it- The problem comes when they move into an area they can’t be cleared from because of a predisposing factor . . .- When they start growing, they produce no reactive toxins, but do produce a nasty host inflammatory response
Occurrence: sporadic, endemic, epidemic, pandemic
Sporadic- occur in a pop w out any periodicityEndemic- usual number of cases of a particular disease in a popEpidemic- short term inc in occurence of a disease in a popPandemic- long term inc in incidence of a disease in a very LARGE pop (influenze)
In what type of individuals are typically infected by pseudomonas? (not species, but general)
Debilitated Hosts
It is an accidental, common soil microorganism
What are the 2 possible ways to collect specimen?
1. direct specimen collection
2. indirect collection
L. pneumonphila pathogenicity is due to?
1. Does not activate the alternate C' pathway2.Elaborates CYTOTOXIN- interferes with O2-dependent phagocytosis3. Beta-lactamases4. Endotoxin
What are the common manifestations of Strep pneumoniae?
- *Leading cuase of Otitis media and sinusitis- Leading bacterial cause of meningitis (espec elderly)- Leading cause of community ac pnemonia- Sepsis
What are 3 types of agglutination tests?
1. rapid plasma reagin test for syphilis
2. weil-felix test for rickettsial disease
3. latex agglutination test
What is the diagnosis of Escherichia coli ?
lots of examples – see labLook for lactose positive gram neg rods - Variety of toxins are species-specific
1. Why does CV-I complex not stick to gram (-)?
2. What is applied?
1. Thin peptidoglycan and outer membrane layer does not prevent extraction
2. safranin is added
What distinguishes a prokaryote from a eukaryote (3)?
1. Packaging of DNA - no nucleus, no histones
2. Cell wall composition - peptidoglycan
3. No complex, membrane-bound organelles for internal structures
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