Bacteriology Flashcards

Terms Definitions
bull-neck edema
Condensed, walled-off nucleoid and cytoplasm surrounded by a spore coat (resistant to microwaves, chemicals, desiccation, heat, and antimicrobials)
pseudomembranous colitis
Clostridium difficile
metachromatic granules
genus Corynebacterium
Criteria for classification of results as "susceptible" or "resistant"
TCA cycle
kreb's cycle
Puerperal fever, Childbed fever
toe web infection
P. aeruginosa
cause of pertussis
Bordatella pertussis
Bacteria attached to surfaces and encased in a hydrated polymeric matrix containing polysaccharides, proteins, and nucleic acids
Effectors (Effector toxins)
Protein toxins that are injected from the bacterium directly into the cytosol of hte host cell via injectosomes
Clostridium perfringens
Causes wound infection and gas gangrene in all species
Antimicrobial selection for Staphylococcus
Penicillinase-resistant penicillins, cephalosporins, clavulanate/amoxicillin, macrolides, trimethoprim/sulfas, chloramphenicol, aminoglycosides, quinolones
60-80% has B-lactamase
Resistance issues with B-lactams and tetracyclines
Transduction of B-lactamase gene
Inducible B-lactamase genes
Broad spectrum B-lactamases (cephalosporins)
Methicillin resistance
gram -ve intracellular organism
gram +ve rode anaerobic
occurring occasionally or scattered
Oxidative phosphorylation=
electron transport system
genus Nocardia
aerobic bacilli; resemble mycobacterium, and cell borders contain a little mycolic acid, like mycobacteria; transiently acid-fast; spectrum of organisms ranging from true bacteria to nearly fungi
Clostridial toxins
neurotoxins; metalloproteases that work by targeting the snare complex, which is involved in neurotransmission; botulin and tetanus toxin are implicated
associated with Helicobacter pylori and Proteus
first line Tb drugs
isoniazide, rifampin
Actinomyces bovis
Causes lumpy jaw
Chronic progressive infection
principally of cattle
development of granulomatous, suppurative legions involving bone and soft tissue
Usually cornea resis to infectionTrauma, burns, cl wear, makeup, antibiotics, and systemic illness can cause diseasePrimary invaders: N gonorrhoeae, N meningitidis, corynebacterium diptheriaepain photobia dec vision and dischargehallmark- corneal epithelial defect w underlying infiltrate in corneal stromaMost common org causing keratits assoc w cl use are:staph aureus, pseudo aeruginosa(soft cl), coag neg staph, strep pneumoniae, and members of enterobacteriacea
membrane-active exotoxins that kill certain white blood cells
study of medically significant occurrences
Group A Strep
Streptococcus pyogenes; most ubiquitous strep species
genus bacillus
aerobic spore forming gram-positive rods; relatively low virulence except for B. anthracis; soil organisms
can spread to cause meningitis
typical pneumonia
Treponema pallidum pertiune
yaws; skin lesions, bones
Elementary Bodies (EB) and Small Cell Variants (SCV)
Condensed forms of obligate intracellular
bacteria taht are suited for survival
outside the host cell (metabolically inactive)
Nocardia asteroides
Cutaneous granulomas and pyothorax in dogs
Mastitis in cattle
Pneumonia in SCID foals
analog of dihydrofolic acid. inhibits syn of folic acid but at a diff part of the pathway. Comno of sulfamethoxazole and trimethoprim inhib folic acid pathway
damage membranes of neutrophils and macrophages (phospholipase??)
the study of disease in populations
the study of frequency and distribution of disease and other health-related factors in defined human populations
restricted to a locality or region
compounds produced by bacteria and fungi that kill or inhibit growth in other species
orderly arrangement of units into groups
detect structurally conserved molecules from microbial pathogens
pattern recognition receptors
leading cause of community acquired pneuomonia
Streptococcus pneumoniae
female; young adults; functionally and anatomically intact urinary tract; outpatient; 80% E. coli; antimicrobial resistance infrequent; oral therapy; respond to short courses
uncomplicated UTI
actin rocket
causes actin polymerization in host cell, creating nest of actin around bacteria, which causes bacteria to be shot out of cell to next host cell
Innate immunity
innate response to bacterial LPS involves CD14 receptors on macrophages which communicate with other toll-like receptors, leading to the production of more macrophages to produce pro-inflammatory cytokines
Tb pleurisy
rupture of tuberculosis into pleural spaces
What to bacteria ribosomes do?
o RNA, proteino Protein synthesiso Sites of action of aminoglycosides, erythromycin, tetracyclins, chloramphenicol- Nucleoid (DNA)
Escherichia coli (Calves)
EPEC: nonspecific enteritis, no enterotoxin. White scourETEC: ST, K99. White ScourEPEC/ETEC can become system in calves w/out colostrum
Pathogenic types of clostridia:
Neurotoxic: potent exotoxins, limited colonization or invasiveness (C. tetani and C. botulinum)
Histotoxic: Invasive and potent exotoxin producers resulting in acute necrosis of tissues (wounds, mm, liver). Includes gas gangrene (C. chauvoei, C. septicum, C. novyi, C. sordelli, C. perfringens)
Enterocolitis: Produce exotoxins active within intestinal tract causing necrosis, food poisoning, diarrhea. May also be histotoxic (c. perfringens, C. difficile)
ABC Transporter
Involved in secretion of toxins, proteases, etc. Usually contain C-terminal secretion signals. ATP hydrolysis drives translocation. Protein moves through a channel formed by hydrophobic domains.
Bacterial replication
binary fission. one cell becomes two.
Internal organs, tissues, and fluids are generally?
microbe free
a departure from normal function or feeling which is noticed by a patient, indicating the presence of disease or abnormality. A symptom is subjective, observed by the patient, and not measured.
Ex. of membrane-active exotoxins?
- Leukocidins
- lecithinase
- hemolysins
deliver toxic message by binding to receptors on cell surface
Science of study of the classification of organisms
manipulation of the herditary material of a cell
genetic engineering
persistence of infection or disease in an animal population at a more or less constant low level
severe sepsis
sepsis with some type of organ dysfunction, increases mortality rate 20%
Borrielia hermsii, duttonii
fast tick born endemic relapsing fever
pathogenic factors of S. epidermidis
PS/A- capsular polysaccharide/adhesin- used to stick to host cell, and also to various plastics; no toxic factors
Weil's Disease
severe disease of liver and kidney caused by Leptospira interrogans
What is Salmonella Disease?
1. Acute gastroenteritis2. Blood infection: enteric fever (tyhoid fever-not common)
Pathogenesis of Pyogenic Infection
Pyogenic = pus (dead leukocytes, liquefied tissue, living and dead bacteria) encapsulation of liq tissue = abscess
Bacteria enter tissues or attach and colonize (adhesins include M protein, capsule, teichoic acids)
Initiate chemotactic leukocytic response
Antiphagocytic factors: capsule and M protein

Produce a variety of exotoxins:
Evoke vascular dilation, exudation of plasma and neutrophils
Hemolysins (leukotoxin), hyaluronidase, proteases)
B-hemolysis: clear zone @ colony on blood agar mostly pathogenic
Sterilization, disinfectant, antiseptic, bactericide, bacteriostasis
Sterilization- destroys ALL life forms 

Disinfectant- kills growing but not the spores

Antiseptic- prevents growth of microbes by destroying them or inhib their growth and activity. Used to clean people 

Bactericide- kills bacteria

Bacteriostasis- growth of bacteria prevented
What are the 3 membrane-active exotoxins?
leukocidins, lecithinase, hemolysins
Opportunistic pathogens
Cause disease when the host's defenses are compromised or when they become established in a part of the body that is not natural to them
What are the characteristics of Mannheimeia?
Lac +
Maltose +
What is colony morphology?
colony morphology - different bacterial colonies vary in size, shape, color, odor, texture
What is collagenase?
Spreading factor that breaks down connective tissue of muscle
disease state in which ther is a bacteremia from pyogenic bacteria and formation of metastic abscesses where thes bacteria localize
refers to level of diesae above usual level for an animal population
method used to amplify a specific DNA sequence in vitro by repeated cycles of synthesis using specific complementary primers and DNA polymerases:
bronzing of the skin; mousy smell; gas gangrene
Clostridium perfringens
What are the characterisitcs of GROUP B STREP – S. agalactiae?
- Gram positive- Catalase negative- Less pathogenic than GAS - Leading cause of sepsis and meningitis in neonates- Normal flora in lower GI – spreads easily- 10-30% of women have vaginal carriage of GBS
What are the virulence factors for Gram - cocci?
- Polysaccharide capsule- LOS (lipooligosaccharide)o Strong burst in cytokine activity- Pili (for attachment and causing inflammation)- OMP (outer membrane proteins)o For adherence - IgA1 proteaseo splits secretory IgA (takes down the first line of defense)- Antibiotic Resistance
Host Range & Disease of Bacillus anthracis
Ruminants: sudden death, bleeding from orifices, subQ hemorrheages, without prior signs, brief period of fever, edema, blood fails to clot, splenomegaly
Equids & wild herbivores: Fever, restlessness, dyspnea, agitation
Pigs, carnivores: local edema, swelling of face, neck, and lymph nodes
Chronic infections characterized by localized subQ edematous swellings
Stages of clinical infection
Incubation period- time from initial contact with a pathogen to the appearance of the first symptom. NO SIGNS OR SYMP YETProdromal stage- earliest symptoms but usually not char of the specific pathogenAcute stage- full effects of bacterial over growth and pathogenic factors observed. largest number of pathogens.Decline phaseConvalescent stage- recovery period.
Ultrastructure of biofilms
can be single or mixed species; usually occurs as groups of microcolonies
Localize infection:
An infection that is limited to a specific part of the body and has local symptoms
What is a vehicle?
any inanimate material commonly used by humans that can transmit infectious agents
What is required for adhesion?
Bacterial adhesin and host receptor
Reservoir vs. source
- Reservoir is primary habitat in natural world from which pathogens originate
- source is the ind. or object from which infxn is actually acquired
What are serotypes?
Members of a species that stimulate distinct antibodies, because of distinct surface molecules
ex. O157:H7; Escherichia coli O157:H7
How does fluoroquinolone inhibit bacterial DNA replication?
Targets bacterial gyrase and topoisomerase
number of cases of a given disease in a given population
large amounts of N and H gas that leads to swelling
Clostridium perfringens
pathogenicity factors of S. aureus
catalase- enzyme which splits H2O2 (all Staphylococcals have this); coagulase- allows conversion of host fibrinogen to fibrin, which then coats bacteria, hiding it (only S. aureus produces this); hyaluronidase; staphylokinase; B-lactamases; Protein A- wall protein that binds to IgG to competitively inhibit and inactivate complement; peptidoglycan- components of wall can have endotoxin-like attributes
cause of 75% of cases of traveler's diarrhea
enterotoxicogenic E. coli
What is the microbiology of Staphylococcus?
- Grape-like clusters, 1 micrometer diameter- Non-motile- Don’t produce spores- Have capsule (evade phagocytosis)- ALL are catalase positive
Immunologic tests: Immunoflur microscopy
Ag-Ab reaction made visible with a fluorescent dye using UV light. Direct is used to detect microorgs and Indirect is used to detect antibodies
What is a convalescent carrier?
An individual who is clinically recovered from an infectious disease but is still capable of transmitting the infectious agent to others.
Are the P. multocida typically capsulated or not? How can this contribute to
Commensal variants are typically noncapsulated, making them less resistant.

Though they contain the genes to make capsulated variants, which during times of stress may over populate and then cause diseases associated with P. multocida
What are the 3 mechanisms of recombination?
1. conjugation
2. transformation
3. transduction
3 virulence factors of Listeria monocytogenes
1. internalin- helps attach bacteria to endothelial cells, inducing self-phagocytosis; 2. listeriolysin-O- replicates inside cell, than uses this to get out before oxidative burst; 3. ActA (actin rocket)- causes actin polymerization in host cell around the bacteria, and leads to the bacteria being shot out through the membrane into the next host cell
toxic factors of Group A Strep
capsule of hyaluronic acid (retards phagocytosis); M-protein on fibrils (avoids phagocytosis); lipotychoic acids (one group focuses on binding to pharyngeal epithelium)
What is the pathogenesis of the GI salmonella strains?
- Infect gut epithelium- Digest mucosal glycocalyx- Invade enterocytes in large or small bowel- Pro-inflammatory cytokines production is stimulated- Diarrhea results from inflammation short-term- Long term: destruction of mucosa, ulcers
What is in a gram - cell wall?
- Minimal layer (10%) peptidoglycan- Periplasmic spaceo Where hydrolytic enzymes and antibiotic inactivating enzymes are stored- Outer wall with Lipopolysaccharideo AKA Endotoxino Provides permeability membrane barrier- Porinso Can genetically change porin size to disallow movement of antibiotics in and out
Cell wall agent used for mycobacteria
isoiazid and ethionamide- interefere w syn of mycolic acids

ethambutol and cycloserine inhib other cell wall constituents
Areas that have indigenous biota
Human skin, GI tract, mouth, large intestines, respiratory tract, genitourinary tract
In a mixed infection w/ both facultative and aerotolerant anaerobes, which is a precursor for the success of the other?
Facultatives create an environment allowing aerotolerant to grow
How is a fimbriae a virulence factor?
Mediates attachment (acts as receptors/adhesins) to host tissues and allows colonization
How is sexual differentiation determined?
Presence or absence of sex factor "F" which is an extrachromosomal, autonomously replicating DNA molecule
Type 2; pyogenic exotoxins; 60% of diagnosed cases
Type 2 Necrotizing Fascitis; involves GAS; dishwater pus
What are the characteristics of GROUP C STREP – S. dysgalactiae?
- Occur in patients with chronic underlying disease- HIV, ETOH, IV drug use- Usual manifestations from pharyngitis to sepsis
how many estimated nosocomial infxn cases are there per year?
2-4 million - indicates importance of medical asepsis
How does the strain on multocida in fowl differ from other species specific strains?
Not typically commensal in URT
What else can R factors carry?
Resistance to heavy metals or for synthesizing virulence factors
What are hte characteristics of genus stroptococcus?
- Form chains (only divide in one plane)- Approximately same size as Staph (1 micrometer)- Don’t form spores- Not motile- ALL catalase (-)- Some of the most important clinically- Vary in hemolytic qualities
What does the type and severity of the infection by pathogen depend on?
Pathogenicity of organism
Condition of host
Immunologic tests: slide and tube and latex
Slide and tube agglut- cells agglut by AgLatex agglut- either Ag or IgG Ab absorbed to surface of latex beads. Add Ag or Ab to see agglut.

Used for: Streptococcus pneumoniae, neisseria gonorrhoeae, N meningitis, staphylococcus aureus
1. What are R factors?
2. What is the magnitude of information that is transferred?
1. Carry genes for resisting antibiotics
2. can confer multiple resistance to antibiotics to 1 strain
What are the 4 modes of action of antimicrobial agents?
1. effects on cell wall
2. effects on cell membrane
3. affect protein and nucleic acid synthesis
4. alter protein function - denature
deer/dog tick
membrane-bound receptors
bullus impetigo
Staph. aureus
Rx of diptheria
lone star tick
Antimicrobials for Gram Positive Aerobes
Concentration of antimicrobial drug sufficient to inhibit isolate's growth in vivo not achievable and/or tolerated
Escherichia coli
gram-negative; lactose-positive; causes GI, UTI (90% of cases), mainly, and the 3rd cause of neonatal meningitis, pneumonia, skin infection
causes human granulocytic ehrlichiosis; deer/dog tick
S. pneumoniae
-gram positive-alpha hemolytic-diplococci-optochin sensitive-fermentates inulin-antiphagocytic capsule-diseases: pneumonia; septicemia + otitis media in infants
Clostridial spp for Neurotoxic Clostridia
Clostridium tetani
Clostridium botulinum
Aerobic saprophytic soil organisms
Filamentous, gram positive rod
PARTIAL ACIDFAST staining differs from Actinomyces
Causes suppurative and pyogranulomatous reactions in immunosuppressed hosts or compromised tissues
Rarely produce sulfur granules
Susceptibility: Trimethoprim/sulfas, tetracyclines (pennicillin NOT ok b/c lipid cell wall is acidfast)
gram -ve faculative anerobic
gram -ve rode aerobic
organ failure, coagulation abnormalities and cardiovascular derangements that occur due to progression of SIRS and sepsis
rose-spot rash
Salmonella enterica (typhoid fever)
endocarditis, IV/renal catheter infections, burns, prosthetic joints
Staph. epidermidis
causative agent of gingivitis
anaerobic spirochetes
Clostridium haemolyticum
Causes bacillary hemoglobinuria (redwater)
Predominantly in mountain valleys of western US, esp wherever liver flukes occur.
Death by lysis of erythrocytes
Beta Lactam antimicrobials
Penicillins and Cephalosporins
Inhibit phagocytosis, mask surface cmpts like LPS, and can mimic host antigens to confuse the immune system
enzyme which destroys plasma membranes, especially those of RBCs (a toxin of c. perfringens)
severe generalized high protein pulmonary edema secondary to a severe vasculitis
calculates percentage of characteristics that two groups have in common
numerical taxonomy
Streptococcus Pneumoniae
MOST IMPORTANT CAUSE OF COMMUNITY-ACQUIRED PNEUMONIA; gram positive cocci; catalase negative
Erysipelothrix rusiopathiae
non-spore-forming gram positive rods; common route of transmission fish to humans; produce some spreading factors, but no invasive factors, so must spread through existent cut or abrasion; cellulitis usually on hands ("fishfinger"); RED DISEASE
like Salmonella, Shigella is lactose negative; non motile; non hydrogen sulfide producing; usually fecal-oral route via water supplies; 4 types- S. dysenteriae, flexneri, boydii, sonnei (90% of cases); dysenteriae and flexneri are most virulent, in undeveloped countries; boydii is usually via food/water; pathogenesis- bloody diarrhea with mucoid stools, inflammation, colitis, ulcers; spread via actin rocket (like Listeria); suspect with inflammatory diarrhea
Secondary Tb
multiple granuloma; rupture of tubercles with release of organisms; significant and sudden weight loss; chills, fevers, night sweats; abnormal chest x-rays with significant destruction of lung tissue; reactivation of an infection that was latent; can range from sputum to a cavetacious disease
sunburn rash
TSS; S. aureus or GAS
Helicobacter pylori
common diseases: gastric ulcer, gastric carcinoma; virulence factors: urease- breaks down urea, producing ammonia which neutralizes the acid of the stomach; mucinase/motility- for spreading using flagella to push into mucosal cells; Vac A toxin- intercytoplasmic vaccule inducing toxin which causes apoptosis, and may help induce ulceration; adhesins- aid attachment so they can hold on in stomach; CAG proteins
What are the Coccobacilli?
1.Hemophilus – “blood-loving”2.Bordetella
Importance of Urease in UTI caused by Staphylococcus
Urease hydrolyzes urea into ammonia, which
increases the pH and reduces the solubility of
salts, which precipiates out of solution and
forms phosphate (struvite, apatite) uroliths).
bacterial chromosome. single. no nuc mem or histones. dna attached to plasma mem.
What are the characteristics of Franciscella?
Define sterilization?
Destruction of all microbial life
ability to detect a true negatrive
leading cause of death by bacteria worldwide
icterohemorrhagic; shaped like a question-mark; penetrates mucous membranes, skin; some manifestations may be autoimmune induced; Weil's Disease- severe liver and kidney disease;
symptoms of Leptospirosis
greenish discharge; treatment with KOH releases fishy odor
Gardnerella vaginalis
80-90% of Escherichia coli strains causing UTIs
uropathogenic strains
phagosome-lysosome function
process by which phagocytes sequester microbes in a vacuole until the phagosome and lysosome fuse, introducing hydrogen peroxide and superoxide radical into the vacuole, which kills the microbe
Borrelia burgdorferi
black-legged deer tick transmits Lyme Disease
the modifications an organism has made to attack, colonize, grow and spread in a host
What is Moraxella?
- Easily mistaken for NeisseriaCommon Manifestations of M. catarrhalis: - 3rd leading cause of Community Ac pnemonia- Otitis, sinusitis, bronchitis – children- High colonization in asthmatic children
Ulcerative lymphangitis
Pigeon breast, pigeon fever, dryland distemper
Caused by equine biotype of Corynebacterium psuedotuberculosis
Deep abscesses in inguinal and pectoral regions
Seasonal occurence
Susceptibility: Penicillins, tetracyclines, sulfonamides, macrolides
Treatment ineffective in walled off abscesses
Exist in localized patches to make integrated pathways so the bacteria can make decisions about which nutrient to move towards.
Keratitis: Mycobacterium chelonae
branching filamentous, club shaped rodshas mycolic acids in cell wall--> positive acid fast rxnreq complex media for growthcause would infectionsare everywhere. no person to person transisolation and biochem teststreat- test for sensitivity. amikacin
Chlamydia Trachomatis: Inclsuion conjunctivitis
Infects epithelial cells--> lymphoctes enter--> devel of folliclesPurulentNo scarringMilder than trachomain genital tract, cervix, urethramost common form of neonatal conj Can get from swimming in gross poolssee follicles and discharge, look for inclusion bodies, DIF, ELISA, PCRTreat- systemic. infants- azithromycin adults- azithromycin, doxycycline ofloxacin
Biological vectors?
actively participates in a pathogens life cycle
a disease that is constantly present to a greater or lesser degree in people of a certain class or in people living in a particular location
Define decontamination?
Mechanical removal of most microbes from an animate or inanimate surface
require oxygen free conditions for growth
obligately anaerobic
large chromosomal regions that carry genes for virulence factors
pathogenicity islands
causative agents of otitis externa
Pseudomonas aeruginosa (Swimmer's Ear); S. epidermidis; S. aureus
2 types of lower UTI
cystitis (bladder infection); urethritis
Chlamydia psittaci
found in poultry workers; leads to atypical pneumonia
What are the common illnesses associated with Gram - cocci?
1. Meningococcemia2. Menintigits
What are endotoxins?
- Alarm Reactions- Fever- Complement activation- Macrophage activation- B-lymphocyte stimulation- Hypoglycemia- Circulatory effects (increased permeability of capillaries, vasodilation)- Shock, DIC (Disseminated intravascular coagulation)- No toxoids can be produced; endotoxins not used as antigens in any available vaccine* Cytokine-mediated reaction may also cause premature labor and spontaneous abortion (Cuidado con UTI in pregos)*Gram positives have NO endotoxins but they do have other cell wall fragments that can stimulate the immune system
Susceptibility testing: Etest
paper strips w antimicrobial agent concen placed on agar surface. After incubation elliptical zone of inhib is formed. MIC is read where growth intersects the E test strip. Clear areas are where the bacteria doesnt grow
Dissemination in the host
Intracellular pathogens may cause lysis or can remain in cells which are transported to lymph nodes and can enter the blood stream. Some pathogens enter deeper tissues by passing btw epithelial cells Pathogens that can go into blood have special mech to acquire iron
aerotolerant anarobes
dont utilize oxygen. can survive if its present. metab is fermentative and employs anaerobic resp
site of action is more localized than endotoxin
Pathogenicity islands
\"large\" inserts of DNA that include virulence genes not found in nonpathogenic members of the genera
What is a genus?
group of related species
ex. Escherichia
What is a fimbriae
- thin, hair-like filaments
- straighter and shorter than flagella
- over entire cell surface
- on many gram (-); few gram (+)
What is lecithinase?
destroys plama membrane, esp. around RBCs (phospholipase)
e.g. the alpha toxin of Clostridium perfringens
Soluble mediators of immunity
complement and acute phase proteins
serve as breakage sites and code for transposase
E. coli; Klebsiella; Enterobacter; Proteus; S. saprophyticus
causative agents of community-acquired UTIs
2 causes of bacterial meningitis
Strep pneumoniae and Neisseria meningitis
predisposing factors to S. aureus
WBC chemotaxis defect (Down's syndrome, diabetes, RA); antibody opsonization defect (complement deficiency); intracellular killing defect (after phagocytosis, inability to mount H2O2 burst); severe skin trauma; prior infections (reduced granulocytes); chronic underlying disease; recent administration of antibiotics
Rx of otitis media
start with amoxicillin, although there is a great deal of resistance due to overuse
cold agglutinins
antibodies made in response to RBCs at 4 degrees centigrade that causes them to coagulate, used for Dx
Describe the bacteria cell wall.
o Peptidoglycan • sugar backbone with peptide side chains cross-linked• rigid support, protect v osmotic pressure, site of PCN actiono Outer membrane of gram-neg• Lipid A (puts toxin in endotoxin)• Polysaccharide (Ag for lab dx)o Surface fibers of gram-pos• Teichoic acid (rarely used for dx)
What are the pathogenic Gram - Cocci?
1. NEISSERIAa. N. gonorrheab. N. meningiditis2. MORAXELLAa. M. catarrhalis3. ACINETOBACTERa. A. baumannib. A. lwoffii
Pathogenesis of Rhodococcus equi
Foals at-risk as MAb declines (peak incidence 6-12 weeks) Passive transfer important
Neutrophils are fully competent bactericidal defense
Infection largely within macrophages/monocytes b/c virulence factor allows entry into macrophage (Entry via non-Fc recep (CRs) allows evasion of Ab-mediated killing in macrophages and intracellular survival). Presence of vapA plasmid necessary to arrest phagosome maturation
chronic pyogranulomatous inflammation
Toxins: exotoxins: Superantigens
bacterial proteins that bind to MHC class 2 on APC and T cells. This releases IL-2 which leads to the release of other cytokines. This causes an autoimmune like response which can be life threatening. Ex) Staphylococus aureus and streptococcus pyogenes
the number of new cases over a certain time period
What is an asymptomatic carrier?
An asymptomatic carrier (healthy carrier or just carrier) is a person or other organism that has contracted an infectious disease, but who displays no symptoms. Although unaffected by the disease themselves, carriers can transmit it to others.
What are biological vectors?
Actively participates in a pathogen's life cycle
Examples of A-B exotoxins?
- neurotoxins like tetanus; botulinum toxins
- cytotoxin such as diphtheria toxin inhibits protein synth
- enterotoxin such as cholera toxin and enterotoxins of e. coli cause diarrhea and/or vomiting
What are sequelae?
long term or permanent damage to tissues or organs
Besides genes for own replication, what other genes do plasmids carry (other phenotypic characteristics)?
- antibiotic resistance
- biodegradative enzymes
- enterotoxin and hemolysin production
three subunits of LPS
O antigen, Core(KDO) and lipid A
pathogenesis of typhoid (enteric strains of Salmonella)
few GI symptoms; organisms attract phagocytes from Peyer's patches, then prevent phagosome-lysosome function; can infect many tissues, especially gallbladder and liver
peptidoglycan protein complexes
gram + complement of endotoxin in gram - bacteria; very similar effect on host humoral system
subversion of phagocytosis
a form of bacterial subversion of the cell-mediated response in which organisms produce toxins called leukocytins which kill phagocytes; others produce type 3 secretion systems that inject apoptosis-causing proteins
fever; edema; chills; urinary frequency; signs of obstruction; swollen prostate
symptoms of Type 1 Bacterial Prostatitis
What shape is H. influenzae in CSF?
gram-negative coccobacilli; typically bacilli
How do you ID Campylobacter (Spirillaceae)?
- Gull-wing shape- Motile via single polar flagella (salmonella and ecoli which have peritryious-lots of flagella)-campy plates can be used to indentify using
Escherichia coli (Pigs)
Neonatal enteritis: ETEC w/ LT and or ST +K88. Watery diarrhea in first 12 hours; high mortalityWeanling enteritis: ETEC with LT/ST but no adhesion. Lower mortality, usually hemolyticEdema disease: EHEC, vasoactive toxin causes toxemia
Invasion of host cells
By invading host cells, bacteria can avoid the host defense immune system. It also uses the nutrients from the host cell. The way the bacteria enter the host is by the host cell internalization pathway. Specific adhesins called invasins bind to host cell receptors.
Virulence factors that contribute to tissue damage
Extracellular enzymes and Bacterial toxins
How is gram (-) outer membrane different from the cell membrane?
Contains specialized polysaccharides and proteins
What is generalized transduction?
- viral infxn of donor bacterium causes denaturation and fragmentation of bacterial DNA
- replication & maturation may result in incorporation of any portion of bacterial genome into viral capsid
- viral capsid containing bacterial DNA can infect and introduce DNA into recipient bacterium
- can be incorporated into nucleoid and expressed
What are the origins of antimicrobial drugs?
eg. Streptomyces, Bacillus, mold, Penicillium, Cephalosporium
What is a biota?
- normal colonists or residents of healthy body surface
- harmless or beneficial
- small # can be pathogenic
- broad spectrum antimicrobials can destroy some beneficial specimen
7 forms of bacterial subversion of cell-mediated response
1. subversion of phagocytosis2. depression of normal white cell function3. inhibition of chemotaxis4. inhibition of phagocytic ingestion of microbe5. inhibition of phagosome lysosome function6. hiding in caveoli7. inhibition of cell-to-cell communication
What does S. saprophyticus affect?
Primary cause of UTIs in young females- Endogenous in colon
Haemophilus influenzae (assoc w conjunctivitis)
6 strains. Haem aegyptius was a distinct species but now a biogroup in influenzae species. Maj of invasive diseases(meningitis) caused by serotype b strainsGram neg, coccobacilli, may have capsulesreq blood factors. X(hemin) V(NADP). Use choc agar. considered fastidiousCapsules(PRP) resist phagocytes + LPS virulentBoth eyes, hyperemia(inc in blood), eye dischargeCause pharyngitis, otitis media, meningitisHumans only hostNonencap(80 %) in nasophar, conj, genital tract.Resp drop transaffects kids
What disease is caused by franciscella tularensis?
Tuleremia in humans
Vector disease typically carried by rabbits

Most animals are resistant.

LPS is responsible for signs for signs of disease
What is a population growth curve?
Depiction of population changes in bacterial culture
What is a noncommunicable disease?
Does not arise through transmission of infectious agent from host to host
- acquired through some other, special circumstance
three major components of gram negative bacteria
inner membrane, periplasm and outer membrane
2 toxic factors of Clostridium difficile
1. toxin A- enterotoxin that produces watery diarrhea; 2. toxin B- cytotoxin that causes inflammation
What are the 4 types of Shingella?
1. Shigella dysenteriae (A)2. Shigella flexneri (B)3. Shigella boydii (C)4. Shigella sonnei (D) ((90% of cases in this country)
Different parts of the body vary in??
temp, pH, nutrients, and O2 tension
Why can transcription and translation occur simultaneously?
There is no physical separation by nuclear membrane
toxic mechanism of Escheria coli ST (thermo-stable) toxin
similar to action of cholera, although point of attack is cGMP levels
What are the toxic factors of Group A Strep?
- Capsule of hyaluronic acido Retards phagocytosis, o Acts as binding protein for epithelial cellso Has little immunogenicity (looks like human HA)- M-protein on fibrils – outermost structureo Major virulence and resistance factoro Avoids phagocytosis and binds to fibrinogino May initiate hallmark shocko Produce post-infxn sequellaeo More than 100 kinds- Lipotychoic acidso Used to bind to other cellso One group focuses on pharyngeal epithelia
What is the result of super-antigens binding to MHC class II?
the release of high levels of cytokines
What is the importance of porin?
Form a channel that allows passage of small molecules (PCN)
nucleic acid synthesis is the target of what?
a target of antibiotics; 2 ways- 1. directly affecting enzymes involved in DNA replication, drugs like quinolone attach to DNA gyrases of bacteria, 2. indirectly affecting necessary precursor molecules that are used to make DNA, shuts off folic acid synthesis, via sulfa drugs like trimethaphan and sulfamethoxypyridazine
1. What is transduction?
2. What do bacteriophages replicate as?
3. What can occur with host DNA during this process?
1. DNA of one cell introduced into another by virus infection.
2. obligate intracellular parasites
3. cellular DNA can accidentally be incorporated into new infectious viruses
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