Clinical Bacteriology Flashcards
Mention 5 diseases that are frequently caused by Staphylococcus aureus!
folliculitis, furunculus, bullous impetigo, osteomyelitis, food poisoning, pneumonia etc.
Mention 2 toxin-mediated staphylococcal diseases!
toxic shock syndrome (TSS), scalded skin syndrome, food poisoning
Mention 3 toxic products produced by Staphylococcus aureus!
TSST (toxic shock syndrome toxin), enterotoxin, exfoliatin, leukocidins, hemolysins
Which is the most virulent species of the Staphylococcus genus?
S. aureus
Which enzymatic virulence factor is characteristic exclusively for Staphylococcus aureus?
exocoagulase
Which biochemical test can be used to differentiate staphylococci from streptococci?
catalase test
Which antibacterial drug is the first choice in serious infections caused by methycillin sensitive Staphylococcus aureus (MSSA) strains?
oxacillin (cloxacillin, flucloxacillin)
Which antibacterial drug is the first choice in serious infections caused by methycillin resistant Staphylococcus aureus (MRSA) strains?
glycopeptides (vancomycin, teicoplanin)
In which disease is Staphylococcus saprophyticus considered an obligate pathogen?
cystitis in young women
Which cell constituents determine the group-specific, and the type specific antigens of Streptococcus pyogenes, respectively?
group specific: C- polysaccharide
type specific: M protein
Mention 3 enzymes produced by Streptococcus pyogenes that enhance the spread of the bacterial infection in the body!
Streptokinase (fibrinolysin), hyaluronidase, streptodornase (DNAse)
List 3 diseases caused by Streptococcus pyogenes in the skin or in subcutaneous tissues!
impetigo, erysipelas, cellulitis, necrotizing fasciitis, myonecrosis
Mention a toxin-mediated streptococcal disease; specify the name of the toxin and its mechanism of action!
Scarlet fever - erythrogenic toxin – superantigen causing capillary destruction Streptococcal toxic shock syndrome (TSS) – TSST - superantigen
Mention 2 poststreptococcal diseases!
Glomerulonephritis, rheumatic fever, (erythema nodosum, chorea minor)
Which product of Streptococcus pyogenes has a major pathogenic role in poststreptococcal diseases?
M protein: may induce hypersensitivity reactions
How long does immunity against scarlet fever exist? Which immune effector mechanism is involved?
Life-long immunity. Antitoxic antibodies are involved.
What is the drug of first choice in Streptococcus pyogenes infection?
Penicillin-G, penicillin V / amoxicillin
What is the patomechanism of post-streptococcal rheumatic fever?
type II hypersensitivity (cytotoxic antibodies)
What is the patomechanism of post-streptococcal glomerulonephritis?
type III hypersensitivity (immune complexes)
Which Streptococcus species plays major role in the meningitis of newborn babies?
Group B Streptococcus (S. agalactiae)
What is (are) the major causative agent(s) for native valve infective endocarditis?
Viridans streptococci
Mention 2 diseases that are frequently caused by enterococci!
urinary tract infections, endocarditis, intraabdominal and pelvic infections
What are the specific morphologic features of Streptococcus pneumoniae?
Gram positive diplococcus, lancet shape, capsule.
Mention 3 diseases that are frequently caused by Streptococcus pneumoniae!
Pneumonia, meningitis, sinusitis, otitis media, sepsis
What fast diagnostic procedure can be used in acute Neisseria gonorrhoeae infection?
Demonstration of bacteria (intracellular in PMNs) from urethral discharge by Gram or methylene blue stain; PCR amplification of bacterial DNA
What kind of immunity develops after Neisseria gonorrhoeae infection?
Partial immunity of short duration; no protection from reinfection
Specify at least 2 of the most important manifestations of disseminated gonorrhoeal infections!
arthritis, skin lesions, (endocarditis, meningitis)
What is the major manifestation of Neisseria gonorrhoeae infection in newborns? How can it be prevented?
Blenorrhoea (ophtalmia) neonatorum; silver acetate eye drops or erythromycin ointment
Mention at least 3 major virulence factors of Neisseria gonorrhoeae!
pilus, outer membrane proteins, LOS (lipooligosaccharide), IgA protease
Mention at least 2 major virulence factors of Neisseria meningitidis!
polysaccharide capsule, LOS, IgA protease
What is the site of entry of Neisseria meningitidis infection? Which diseases are caused by this bacterium?
The site of entry is the nasopharynx (transmitted by airborne droplets). Meningococcemia and acute (purulent) bacterial meningitis.
What kinds of prophylactic measures are available against Neisseria meningitidis infections?
Chemoprophylaxis: rifampin or ciprofloxacin.
Vaccination: capsular polysaccharide (types A, C, Y and W135). Vaccine against type B: contains different recombinant proteins.
Which rapid diagnostic methods can be used in the presumptive diagnosis of purulent bacterial meningitis?
Gram or methylene blue stain of CSF sediment
Demonstration of bacterial capsular antigens by latex agglutination (from CSF) Polymerase chain reaction (PCR)
What does the vaccine against Haemophilus influenzae contain?
type b capsular polysaccharide conjugated to a carrier protein
Which are the portals of entry of Bacillus anthracis?
Skin, lungs, gastrointestinal tract
Mention 3 important bacteria involved in nosocomial (hospital-acquired) infections!
Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, Escherichia coli, Clostridioides difficile
