Term
|
Definition
bacteria favored by fatty acids, lipids from sebaceous glands
coagulase negative Staphylococcus
Staph aureus
Proprionobacterium acnes and other diphtheroids |
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Term
|
Definition
| Staph aureus (25-30% of people are chronic nasal carriers) |
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Term
|
Definition
Strep viridans (alpha-hemolytic, can cause endocarditis; includes Strep sanguis and Strep mutans)
Neisseria spp
Moraxella catarrhalis
Strep pneumoniae
Actinomyces spp |
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Term
|
Definition
usually <1% of people
Can cause epidemic meningitis if carriers in given area is >20% |
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Term
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Definition
Sluggish motility, high counts of bacteria
Bacteriodes (anaerobes) outnumber E. coli (aerobes) 1000 to 1
Clostridia
Lactobacilli
Anaerobic strep
Enterococcus faecalis |
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Term
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Definition
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Term
Vaginal
Pre-pubertal and post-menopausal |
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Definition
Lock glycogen, secretions alkaline and flora mixed
UTI and bladder colonizations are common during the post menopausal years |
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Term
Vaginal
reproductive years |
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Definition
glycogen as substrate for acid tolerant lactobacilli, Candida
Anaerobic Strep (most common cause of newborn meningitis is group B strep, E. Coli; passed during childbirth)
Diphtheroids
Clostridia (inhibitory effect on coliforms from rectum, reduce UTI) |
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Term
| Anterior urethra and uterine cervix |
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Definition
coagulase negative Staph
Diphtheroids
Strep
Bacteroides
Anaerobic Strep |
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Term
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Definition
blood
CSF
joint fluid
pleural fluid
intraabdominal or pelvic fluid |
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Term
| Potential superinfection flora |
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Definition
Hospitals - MRSA, resistant gram - rods (Pseudomonas and Acinetobacter)
Crowded areas - Neisseria meningitidis
Gallbladder stones - Salmonella typhi
Cancer, leukemia or lymphoma - gram - rods including Pseudomonas
Major body burn, pelvic surgery, etc - Gram - bacilli
AIDS pt - Herpes virus, Pneumocystitis carinii |
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Term
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Definition
| secreted low molecular-weight iron chelators which have a high binding capacity for iron |
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Term
| Cytochrome C + Cytochrome-C oxidase |
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Definition
cyto c oxidase: transfers terminal e- from cyt c to O2, generates H2O
Oxidase + : Pseudomonas (usually, Neisseria, Aeromonas, Vibrio (usually)
Oxidase - : Enterobacteriaceae
Cyto c oxidase is not found in anaerobes |
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Term
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Definition
specific peroxidase
2 H2O2 -> 2H2O and O2
catalse + : Staph spp
catalse - : Strep spp and Enterococcus spp (pathogenic gram + cocci) |
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Term
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Definition
Mycobacterium tuberculosis
Pseudomonas aeruginosa |
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Term
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Definition
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Term
|
Definition
E. coli (can utilize O2 depending on conditions)
Strep (aerotolerant) |
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Term
| Motile pathogenic bacteria |
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Definition
Clostridum spp
Salmonella spp
Vibrio cholera
Pseudomonas spp
Campylobacter spp
Helicobacter spp
E. Coli |
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Term
Virulence characteristics
Adherence |
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Definition
Enterotoxigenic (fimbriae) and enteropathogenic (localized damage) E. coli
Pyelonephritis E. coli (p-fimbriae)
Neisseria gonorrhoeae pili |
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Term
Virulence characteristics
resistance to phagocytosis |
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Definition
Encapsulated organisms (S. pneumoniae, H. influenzae) and deficiency of opsonic activity
K1 antigen E. coli (everyone has antibodies against this, but babies dont, can lead to neonatal meningitis)
M protein Strep pyogenes |
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Term
Virulence characteristics
Exotoxins, extracellular proteins, endotoxins |
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Definition
Staph aureus (coagulase - clotting of vessels with localized abscess explains boils)
Strep pyogenes (hyaluronidase, collagenase, hemolysins)
botulism, tetanus, dipheria, travelers diarrhea (E. coli), hemorrhagic colitis (E. coli), antibiotic associated colitis (clostridium difficile), gas gangrene (clostridium perfringens and toxins produced, Psudomonas aeruginosa) |
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Term
|
Definition
| toxin by organism in normal growth that produces irregularity in the gut |
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Term
|
Definition
not produced and release normally
biologically active molecules in cell wall (all gram - organisms)
released by lysed gram - cells |
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Term
|
Definition
systemic inflammatory response syndrome
tachycardia, toxicity, decreased BP, labored respirations |
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Term
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Definition
Adult respiratory distress syndrome
clotting of vessels in lung vessels and alveoli |
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Term
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Definition
disseminated intravascular coagulation
activated platelets and damaged endothelium lead to clotting and mortality |
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Term
Virulence characteristics
Invasiveness |
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Definition
tissue tropism - each virus has tissue where there is susceptibility
Hepatitis - liver, Adenovirus - respiratory, Shigella - gut
Rickettsia and Chalmydia |
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Term
|
Definition
related to host genetics and susceptibility
HLA-B27, enteric infection and reactive arthritis |
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Term
| Microbial persistence and latency |
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Definition
M. tuberculosis
DNA (herpes) viruses and retroviruses
emerge w/ stress and have oncogenic potential |
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Term
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Definition
AUG - fMet
GUG - Val (Met if initiator) |
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Term
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Definition
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Term
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Definition
| the appearance of a distinct second-site mutation that reverses the mutant phenotype |
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Term
|
Definition
G converted to 8-oxoG residues, which pairs aberrantly with A residues
G-C to T-A transition |
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Term
| Proofreading DNA replication |
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Definition
| epsilon subunit of DNA polymerase III |
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Term
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Definition
| brought about by site specific recombination mediated by the Hin protein |
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Term
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Definition
1) virulence factor required for cell adhesion
2) acquired copy of shiga toxin gene by horizontal gene transfer by bacteriophage
3) Toxin gene acquired mutations and is an even more potent toxin than that of Shigella dysenteriae |
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Term
|
Definition
bacteriocin which kills E. coli
E. coli |
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Term
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Definition
Degradation of toluene and benzoic acid
Pseudomonas putida |
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Term
|
Definition
Tumor initiation in plants
Agrobacterium tumefaciens |
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Term
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Definition
Antibiotic methylenomycin biosynthesis
Streptomyces coelicolor |
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Term
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Definition
| Resistance to ampicillin, tetracycline, and kanamycin |
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Term
| Streptococcus pneumoniae transformation |
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Definition
| S. pneumoniae secretes a competence pheromone at a specific time near the transition of cultures from growing to stationary phase |
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Term
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Definition
| Only single stranded DNA enters cell, and this remains ss until recombination (unique compared to other gene transfer methods) |
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Term
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Definition
| compartments produced by H. influenzae that bind DNA containing the signature sequence |
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Term
| Integration of lambda phage |
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Definition
| site-specific recombination is mediated by the Int protein between the attB and attP sites in the bacterial and phage chromosomes, respectively |
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Term
| Generalized vs specialized transduction |
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Definition
Generalized - entire, a p host DNA is broken into pieces, some of the viral progeny contains host DNA due to packaging error. Could be any genes
Specialized - as a prophage exits the bacterial chromosome, a piece of host chromosome can be included with the excised DNA. Only genes immediately adjacent to phage attachment site |
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Term
| Rapid diagnosis of drug resistant M. tuberculosis |
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Definition
Infect M. tuberculosis strains with phage containing lux genes (give off light). Only metabolically active cells give off light.
Add antibiotic to growing culture. Subcultures that continue to grow contain bacteria that are resistant to the antibiotic. |
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Term
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Definition
Mechanism of resistance
bacteria either do not take up or actively secrete the antimicrobial agent |
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Term
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Definition
| bacteria degrade, or chemically modify the antimicrobial and convert it to an inactive compound |
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Term
|
Definition
mechanism of resistance
- enzyme can mutate so that it no longer is inhibited by antimicrobial
- bacteria can synthesize a different enzyme that performs the same general function but is insensitive
- increased production of a sensitive target |
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Term
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Definition
Penicillin
cephalosporins
carbapenems
monobactams
cephamycins
β-lactamase inhibitors |
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Term
| β-lactams mechanism of action |
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Definition
covalently bind to active site of transpeptidases and carboxypeptidases (penicillin binding proteins, PBPs) which crosslink peptidoglycan cell wall
Structurally resemble D-Ala D-Ala part of peptidoglycan molecules
Different β-lactams have affinity for different PBP enzymes, which is why certain β-lactams are effective against certain bacteria (different organisms differ in number and type of PBPs) |
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Term
β-lactams
Autolysis vs tolerance |
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Definition
Autolysins - endogenous enzymes that hydrolyze the various bonds present in the peptidoglycan. Required for growth. If enzymes degrade peptidoglycan in absence of active PBP making new material, cell will lyse
Tolerance - Enterococci and some streptococci and staphylococci - β-lactams are bacteriostatic because these bacteria do not produce active autolytic enzymes |
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Term
|
Definition
1) Inactivation by β-lactamases (many gram + species have this)
- cephalosporinases on chromosome of all gram -
- penicillinases encoded on plasmids
2) Altered target (alterations in the PBP gene )
- by mutation
- by recombination between species (transformation by S. pneumoniae)
- new PBP is molecular basis for MRSA |
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Term
|
Definition
Vancomycin and Teicoplanin
binds to D-ala-D-ala (substrate), prevents cross linking
bactericidal |
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Term
| Resistance to Glycopeptides |
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Definition
Gram - bacteria are intrinsically resistant to vancomycin because it can not get through the outer membrane
VR Enterococci use D-ala-D-lactate, which vancomycin does not bind. Gene carried on a transpoon. |
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Term
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Definition
Structural analog of D-ala
Blocks Alanine racemase and D-ala ligase (in the cytoplasms, cycloserine must penetrate the cytoplasmic membrane)
Bactericidal |
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Term
|
Definition
| Prevents recycling of hte undecaprenol carrier that transports peptidoglycan precursor from cytoplasmic side to outside of membrane |
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Term
|
Definition
Streptomycin, gentamicin, amikacin
bind to the ribosome (30S) and reduce the accuracy of the ribosome
Bactericidal |
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Term
| Resistance to aminoglycosides |
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Definition
Inactivation of aminoglycoside by adenylation, phosphorylation, or acetylation
Altered target - mutations in the ribosome
Altered uptake - uptake depends primarily on electron transport to oxygen, thus not effective against anaerobic bacteria (intrinsic) |
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Term
|
Definition
Attach to 30S subunit and prevent binding of aminoacyl tRNA
Bacteriostatic |
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Term
| Resistance to tetracycline |
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Definition
Decreased premeability. Energy dependent efflux of drug out of cell by a pump protein encoded on plasmid
Tetracycline binding protein, plasmid encoded |
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Term
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Definition
erythromycin
Bind to the protein exit tunnel of 50S subunit and block translocation |
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Term
| Resistance to Macrolides and Lincosamides |
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Definition
Altered target - methylation of 23S rRNA, prevents binding
plasmid encoded |
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Term
|
Definition
clindomycin
Bind to 50S subunit and block translation elongation. Interferes with tRNA binding and with protein exit tunnel
Bacteriostatic |
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Term
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Definition
Inhibits translation elongation and peptide bond formation by preventing tRNA from binding to A-site
Bacteriostatic |
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Term
| Resistance to chloramphenicol |
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Definition
Inactivation by chloramphenicol acetyltransferase
Altered uptake by some gram - bacteria |
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Term
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Definition
Linezolid
Inhibit protein synthesis initiation by binding to 50S subunit and prevents joining the mRNA/30S complex
reserved for MRSA and multidrug resistant Enterococcus |
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Term
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Definition
Inhibit dihydropteroate synthetase
Resistance - altered target. Synthesize new dihydropteroate synthetase that has lower affinity for sulfonamides |
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Term
|
Definition
Inhibit bacterial dihydrofolate reductase
bacteriostatic
Resistance by altered target - syn new DHFR that lacks capacity to bind trimethoprim |
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Term
|
Definition
Cirprofloxin, norflaxacin
Block DNA gyrase enzyme
Bactericidal |
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Term
|
Definition
Altered target - chromosomal mutations in the gyrA gene, different DNA gyrase
Altered uptake - chromosomal mutations in E. coli which result in decreased expression of the outer membrane porin, OmpF. Alterations in permeability in QR P. aeruginosa
Altered uptake - efflux of quinolones |
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Term
|
Definition
Large molecule that inhibits RNA polymerase enzyme
Bactericidal
Resistance - altered target - chromosomal mutations in the β-subunit of RNA polymerase that prevent binding |
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Term
|
Definition
cyclic polypeptides that disrupt the phospholipid structure of the cytoplasmic membrane
Bactericidal |
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Term
|
Definition
metronidazole, tinidazole
reduction by nitroreductase generates unstable intermediates and/or free radicals
Requires low redox potential that is only present in anaerobic bacteria
Do not bind to specific enzyme
Resistance by reduced uptake or decreased nitroreductase activity
Also active against some parasites |
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Term
| Membrane disrupting toxins |
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Definition
No separable A-B moieties
Pore-forming - non-enzymatic
(α-haemolysin, Panton-Valentine leukocidin)
Phospholipases - enzymatic
(Clostridium perfrigens α-toxin - Phospholipase C) |
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Term
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Definition
No A-B; stimulate T-cells to make cytokines
form a bridge between the MHC class II and TCRs.
Massive activation of T-cells and subsequent release of cytokines results in fever, shock, and possibly death. |
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Term
|
Definition
C. diptheriae causes diptheria
other corynebacterium aka "diptheroids" and nonpathogenic
Gram+ (variable), nonmotile, club-shaped bacillus
Grow best under aerobic
Nonhemolytic
Catalase-positive |
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Term
| Disease and clinical manifestations of corynebacterium |
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Definition
Nasopharynx - pharyngitis or tonsillitis with malaise, patch of exudate/membrane made of fibrin, leukocytes, and cellular debris; respiratory obstruction can lead to suffocation
Systemic - Myocarditis, CHF, Nervous system including paralysis of soft palate, oculomotor muscles
Cutaneous - skin lesions with graybrown pseudomembrane. simple pustule or chronic non-healing ulcer, common in tropical hot regrions |
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Term
| Epidemiology of corynebacterium |
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Definition
transmission by droplet spread (nasopharynx) and direct contact (cutaneous)
Maintained by asymptomatic carriers
rare due to immunizations in US |
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Term
| Pathogenesis of corynebacterium |
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Definition
Colonize, produce phospholipase D to increase vascular permeability and promote spread, produce toxin (corynebacteriophage, β-phage)
exotoxin by lysogenic strains
simple A-B, A inactivates EF-2 by ADP-ribosylation at diphthamide reside (modified histidine), blocking translocation of polypeptide |
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Term
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Definition
Corynebacterium diphtheriae - diphtheriae toxin
Pseudomonas aeruginosa - exotoxin A
Vibrio cholerae - cholera toxin
E. Coli - LT
Bordetella pertussis - pertussis toxin |
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Term
|
Definition
entirely clinical, no rapid diagnosis
isolate and identify C. diphtheriae, tellurite medium - colonies appear gray/black, catalase test is positive
Elek Immunodiffusion test - antitoxin vs toxic strains plated - form lines of precipitin |
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Term
|
Definition
gram+
motile
catalse-positive
weakly hemolytic |
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Term
| Disease and clinical manifestations of listeria monocytogenes |
|
Definition
Usually involves CNS, meningitis and encephalitis
Neonatal and peurperal infections associated with vaginal colonization. Bacteremic infection in preggers can cause abortion, stillbirth, or premature birth. Transplacental results in granulomatosis infantiseptica. Neonatal meningitis, bacteremia, or both. |
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Term
| Epidemiology of L. monocytogenes |
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Definition
Foodborne transmission and intrauterine transmission
Human resevoir is intestinal colonization
Associated with dairy products which are unpasteurized or were contaminated after pasteurization |
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Term
| Pathogenesis of L. monocytogenes |
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Definition
Phagocytosis or invasion of non-phagocytic cell using "internalin"
Escape from vacuole by lysteriolysin O (LLO)
Multiplication of bacterium in host cell
Movement by actin polymerization
Penetration of neighboring host cell membrane by phospholipase (minimal contact with host immune system) |
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Term
| Diagnosis of L. monocytogenes |
|
Definition
Monocytosis in peripheral blood and spinal fluid
No rapid diagnostics
Can multiple at low temps (contaminated food in fridge)
Tx with Penicillin G, ampicillin |
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Term
|
Definition
gram+
spore forming
motile
certain strains produce enterotoxin and/or pyogenic toxin |
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Term
| Disease and clinical manifestations of B. cereus |
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Definition
Diarrheal syndrome due to heat-labile enterotoxin
Emetic syndrome due to heat-stable enterotoxin
No treatment for food poisoning |
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Term
| Epidemiology of B. cereus |
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Definition
resevoir is soil
spores are resistant to heat, dessication
food poisoning often associated with rice |
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Term
|
Definition
gram+
spore forming
vegetative cells form "bamboo-like" chains
capsulated under conditions of high CO2 or HCO3-
nonmotile |
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Term
| Disease and clinical manifestations of B anthracis |
|
Definition
cutaneous - inflamed papule, central lesion blackens to eschar, gelatinous edema, remains localized
inhalation - hemorrhagic mediastinitis and hemorrhagic meningitis
intestinal - cholera-like gastroenteritis
oropharyngeal - tonsillar or pharyngeal ulceration and psudeomembrane formation |
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Term
| Epidemiology of B. anthracis |
|
Definition
resevoir is soil
occupational exposure following contact with dead animals or their products |
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Term
|
Definition
1) secrete anthrax toxins
2) synthesize an antiphagocytic capsule (proteinacious, not polysacc)
2 A toxins
lethal factor - metalloprotease
edema factor - adenylyl cyclase |
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Term
| Diagnosis of B. anthracis |
|
Definition
Always perform blood culture
Sputum cultures rarely positive. Spores dont germinate until reach mediastinal lymph nodes
CXR - mediastinal widening
No or poor hemolysis
Gooey capsule in 5% CO2
lysis by gamma phage
2 different flurescent antibodies
toxin gene ID by PCR
Tx with Ciprofloxin or deoxycycline |
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