Block 9 Bacteria

klau253's version from 2017-06-02 13:56


Question Answer
E. Coli O157:H7food poison/haemolytic uremia
Neisseria. Meningitidisbacterial meningitis
Neisseria. gonorrhoeaegonorrhoeae (STD), not present as healthy microbial flora
H. pylorichronic gastritis, gastric ulcer
Listeria monocytogenesGr+, rod, causes listeriosis (CNS meningitis and bacteriaemia), food borne, risky population(pregnant, IC, leukemia), actin-based motility(movement not mediated by flagella), facultative intracellular
Mycobacterium tuberculosiscan be gram +ve/-ve*
Chlamydia trachomitisdoes not have a cell wall*, causes STD and trachoma(roughening of inner eyelids)
Micrococcus luteusgeneral harmless skin, mucosa and oropharynx colonizer, but can cause abscess, pneumonia and meningitis in IC pt
Klebsiella pneumoniaecapsulated, bacillus shaped
Borrelia burgdorferispirochete, cause lyme disease
Vibris choleraGr-ve, curved rod, cholera toxin, H2O-oral transmission, colonizes in SI,
Cholera toxin is an exotoxin --> causes loss of fluid and electrolytes via diarrhoea
Clostridum difficileform spores, cause antibiotic associated diarrhoea (pseudomembranous colitis)
Clostridium botulinumGr +ve, form spores, in adults, ingesting performed toxins; infant, botulism toxin produced in gut after ingesting bacterium(contaminated honey), causes muscle paralysis, vision problems, swallowing difficulty
Bacillus anthracisfacultative pathogen (grow and survive in environment as well as in host)
Strep. pneumoniaegram+, cocci, host response leads to pneumonia (can also cause meningitis)
Strep. pyogenesproduces beta-haemolysin to breakdown Hb
Salmonella enterica serovar TyphimuriumGr -, food borne, causes gastroenteritis
Haemophilus influenzaplaces host phosphorylcholine and sialic acid on surface


Gr staining
Question Answer
Gram -veLPS in outer membrane, thin peptidoglycan, presence of periplasm
Gram +veno LPS and outer membrane, presence of teichoic acid, thick layer of peptidoglycan
Exceptionmycobacterium TB can appear either
Chlamydia trachomitisdoes not have a cell wall
Mycoplasmano cell wall


O2 requirement
Question Answer
Aerobicrequires O2
Obligate Anaerobedies with O2
Tolerant Anaerobedoes not use O2, but can tolerate it if present
Facultative Anaerobedoes not need O2, but can use if present
Microaerophilic Anaerobeneed O2, but die in high conc of it


Horizontal gene transfer
Question Answer
Transformationfree DNA taken up
Transductionbacteriophage infecting bacteria
Conjugationclosely related species, plasmid moves from one to another
Transpositiontransposons move from one DNA site to another


Strategies of pathogens
Question Answer
Extracellular pathogenstrep. pneumoniae
Toxin producing pathogens, extracellularClostridium botulinum/tetani, Vibrio cholera, E.coli O157:H7
Intracellular (non-obligate)Salmonella (enterica) typhimurium, Listeria moncytogenes


virulence factors of Strep. Pneumoniae
Question Answer
Capsuleprevents phagocytosis
Surface adhesinsattach to respiratory lining
secretory IgA proteasecleaves IgA and promotes spread of infection
neuroaminidasecleaves terminal acetylated neuraminic acids from sugar residues
pneumolysinspore forming and tissue damage


Virulence factor of Streptococcus pyogenes (gr +)
Question Answer
Beta-haemolysincomplete breakdown of Hb,
EnterotoxinC. diff, cholera, E.coli


Virulence factor of C. botulinum
Question Answer
Botulinum toxinneurotoxin (blocks ACh release in synpas), leads to flaccid paralysis and resp arrest, approved for relief of chronic migraine, excessive sweating and overactive bladder


Molecular mimicry
decorate the outside with molecules that have chemical identity with host molecules
Question Answer
Haemophilus influenzaplaces host phosphorylcholine and sialic acid on surface
Can trigger immune response against autoantigens


Gram +ve
Question Answer
3 Coccistrepto, staphylo, entero
4 bacillibacillus, clostridum, corynebacterium, listeria


Gram -ve
Question Answer
2 DiplococciNeisseria, Moraxella
1 spirochetetreponema pallidum (syphilis)


Exception to gram stain
Question Answer
Mycoplasmano cell wall
Mycobacteriumacid fast stain