MICRO MINIMAL QUESTIONS Flashcards
What does sterilisation mean?
Killing procedure of any kind of germs
What does disinfection mean?
Procedure where the number of germs are reduced to a safety level
Which parameters can influence the effectivity of the sterilisation?
- the number of the germs
- the resistance of the germs
- the concentration of the disinfectants
- the presence of the organic materials
- the initial time
- the presence of the biofilm
Parameters of the hot-air sterilisation cupboard protocol?
- 180 C for 1 hour
- 160 C for 2 hours
- 140 C for 3 hours
Parameters of the autoclaving?
+ 1 atm overpressure, 121 C, for 20-30 minutes
OR
+2 atm overpressure, 134 C, for 10 minutes
Chemical agents used for gas sterilisation?
- Etilene oxide
- Formaldehyde
- Beta-propiolacton
The theoretical background of plasma sterilisation?
- Hydrogen-peroxide (H2O2) in high electric field will form plasma stage.
- The produced free radicals will kill the microbes.
- At the end of the procedure will be produced water, oxygen and other nontoxic products
Biological method used for checking the effectivity of the sterilisation.
- By Bacillus/Geobacillus stearothemophilus spores.
- It the procedure was performed in correct way, the spores cannot be cultivated.
Detection of the presence of pyrogenic material in drugs?
LAL test; the blood of the horseshoe crab will coagulate in the presence of the LPS
What are the disinfectants?
Chemical agents used on non-living surfaces
What are the antiseptic agents?
Chemical agents used disinfection on animate (tissue, skin, mucous membrane) surfaces.
What does serological reaction mean?
Reaction based on antigen-antibody reaction performed in vitro.
What does agglutination mean?
Serological reaction where the antigen is cell mediated
What are the bacterial cell surface antigens?
- O: cell wall
- H: flagella
- K: capsule
What does antibody titre mean?
The highest dilution fold or the lowest antibody concentration where we can see in vitro antigen-antibody reaction.
What does precipitation mean?
Serological reaction where the antigen is soluble (enzyme, toxin or virus particle)
What does iatrogenic infection mean?
Infection caused by medical staff during the investigation or treatment.
What does nosocomial infection mean?
Infection occurred in hospital after 48 hours of the hospitalisation
What are the contents of the vaccines?
Live attenuated microbe;
- killed microbe
- toxoid
- antigens of the microbe
What does native examination of the microbe mean in microbiology?
The microbe is examined without killing procedure
What kind of information can we get by light microscopically examination? (3 examples)
- size of the microbe
- shape of the microbe
- motility of the microbe
- the staining can be examined
The solutions of the Gram-stain?
- Sodium oxalate
- Crystal violet
- Iodine solution
- 96% of ethanol
- Fuchsin or Safranin
What kind of devices can be used for anaerobic cultivation?
- Anaerostate
- Gas-pack jar
- High agar
- Anaerobic chamber
Definitions: bacteriostatic, bactericide
- Bacteriostatic - inhibits bacterial growth
2. Bactericide - kills bacteria
Definition: selective toxicity
- The antibiotic has an effect only on the bacteria, but not on the human host
Chemotherapeutic index?
Dosis tolerata maxima (DTM)/dosis curativa minima (DCM)
Cell wall synthesis inhibitor antibiotics?
- Penicillin
- Cephalosporin
- Carbapenem
- Glycopeptide
Glycopeptide antibiotics
- Vancomycin
- Teicoplanin
Membrane function alternating antibiotics are:
- Polymixines
What are the protein synthesis inhibitor antibiotics? (3 examples)
- Aminoglycosides
- Tetracycline
- Macrolide
- Chloramphenicol
- Linezolid
Nucleic acid synthesis inhibitors are… (2 examples)
- Quinolones
- Rifampicin
- Sulphonamide
- Trimethoprim
Three possible ways of horizontal gene transfer?
- Conjugation (plasmid)
- Transduction (bacteriophage)
- Transformation (uptake of naked DNA from the environment)
Antibiotic resistance mechanism are..
- Enzymatic degradation or modification of the antibiotics
- Efflux pump
- Modifying of the antibiotic binding site
What does MRSA mean?
Methicillin-Resistant Staphylococcus Aureus
What does ESBL mean?
Extended Spectrum of Beta Lactamase enzyme
What does MIC mean?
Minimal bacteriostatic concentration of an antibiotic measured in ug/ml.
What does MBC mean?
Minimal bactericidal concentration of an antibiotic measured in ug/ml
Definitions: MBL, MACI, PACI
- MBL: metallo-beta-lactamase
- MACI: multi-resistant Acinetobacter
- PACI: pan-resistant Acinetobacter
Which 3 vaccines contain capsular polysaccharide?
- Hib (against Haemophilus influenzae type b)
- Preventar/Pneumovax (against 13/23 serotypes of Streptococcus pneumoniae)
- Meningococcus vaccines (against serotypes ACWY) - but NOT B!
What kind of specimen can be sent to the microbiological diagnostic laboratory in the case of typical pneumonia?
Sputum and haemoculture
What kind of specimen can be sent to the microbiology diagnostics laboratory in case of atypical pneumonia?
- Blood
- Urine
- Broncho-alveolar lavage
What kind of bacterial infection can be treated by antitoxin?
Infections caused by bacterial exotoxins:
- tetanus
- botulism
- diphtheria
Which bacteria can be differentiated with catalase test?
- Staphylococci (+)
- Streptococci (-)
Which bacteria can be differentiated with the coagulase test?
Staphylococcus aureus (+) and the other staphylococcus species (-. so called “coagulase-negative staphylococci”)
Microscopic morphology of Staphylococci
Gram-positive cocci, arranged in grape-like structures
Colony morphology of Staphylococcus aureus on blood agar plate
- Average size
- Round colonies with butter consistency
- Golden pigment production
- Beta-haemolysis
What are the non-toxic virulence factors of Staphylococcus Aureus? (3 examples)
- Protein A
- Endocoagulase (clumping factor)
- Exocoagulase
- Adhezins
- Teicoic acid
- Hialuronidase
- Protease
- Lipase
DN-ase
What are the toxic virulence factors of Staphylococcus Aureus?
- Leucocidin
- Toxic shock syndrome toxin
- Exfoliative toxin
- Enterotoxin
- Haemolysin
Disease caused by Staphylococcus Aureus?
- Folliculitis
- Furuncle
- Carbuncle
- Impetigo
- Pneumonia
- Osteomyelitis
- Food poisoning
Diseases caused by Staphylococcus Aureus exotoxins? (2 examples)
- Food poisoning
- Scalded skin syndrome
- Toxic shock syndrome
List at least 2 coagulase-negative staphylococcus species !
- S. Epidermidis
- S. Saprophyticus
- S. Haemolyticus
- S. Lugdunesis
Diseases caused by coagulase negative Staphylococci?
- Nosocomial infections
- Biofilm production on the surface of plastic devices
Which bacterium can cause “Honeymoon cystitis”?
Staphylococcus saprophyticus
Colony morphology of Streptococcus pyogenes on blood agar plate?
- Small
- Pin-point colonies
- Surrounded by large, strong beta-haemolytic zone
Which streptococci show beta-haemolysis?
- Streptococcus pyogenes
- Streptococcus agalactiae
Which streptococci show alpha-haemolysis?
Streptococcus pneumoniae and Viridans streptococci (e.g. S. mutans, S. mitis, S. salivarius)
Which species is the Lancefield group A Streptococcus?
Streptococcus pyogenes
Which species is the Lancfield group B streptococcus?
Streptococcus agalactiae
What is the causative agent of scarlet fever?
Streptococcus pyogenes
Which bacterial virulence factor is the causative agent of scarlet fever?
Streptococcus pyrogenic exotoxin or Erythrogenic toxin
What is the capsule of S. pyogenes made of?
Hyaluronic acid
Disease caused by Streptococcus pyogenes? (3 examples)
- Pharyngitis
- Tonsillitis
- Sinusitis
- Impetigo
- Erysipelas
- Necrotising fasciitis
- Scarlet fever
- TSST
What kind of post streptococcal infections can be caused by Streptococcus pyogenes?
- Acute rheumatic fever
- Glomerulonephritis
Which two streptococcus species show 100% penicillin sensitivity still now?
- Streptococcus pyogenes
- Streptococcus agalactiae
What kind of diseases can be caused in new-borns by streptococcus agalactiae?
In new born meningitis, sepsis, penumonia
Which bacterium is the leading cause of neonatal meningitis?
Streptococcus agalactiae
Microscopic morphology of streptococcus pneumoniae
Gram-positive diplococci
How can be prevented the invasive disease caused by Streptococcus pneumoniae?
By 23 valent polysaccharide capsule (adults) or by 13 valent conjugated vaccine (children, elderly)
Which two bacteria can be differentiated based on their optochin sensitivity / resistance
Streptococcus pneumonia (S) and Viridans streptococci (R)
What kind of diseases can be caused by viridans group streptococci?
Dental decay or endocarditis
What are the two most frequent Enterococcus species?
E. Faecalis and E. Faecium
Microscopic morphology of Neisseria gonorrhoeae?
Gram-negative, non capsulated diplococci
What kind of culture media can be used to cultivate Neisseria gonorrhoeae?
Chocolate agar or Thayer Martin agar
Microscopic morphology of Neisseria meningitidis?
Gram-negative, capsulate diplococci
How can Neisseria meningitidis spread?
By respiratory droplets and will colonize the nasopharynx
What kind of disease can be caused by Neisseria meningitidis?
- Sepsis
- Meningitis
- Waterhouse-Friderichsen syndrome
What kind of diseases can be caused by Neisseria gonorrhoeae?
- Gonorrhoea
- Blenorrhoea neonatorum
- Proctitis
- Orchitis
What is the causative agent of Waterhouse-Friderichsen syndrome?
Neisseria meningitidis
What kind of tests can be performed from liquor in case of Neisseria meningitidis infection?
- Macroscopic examination
- Gram-stain
- Latex agglutination
What can we do prophylactic with the contact person who suffering by Neisseria meningitidis infection?
Chemoprophylaxis by rifampicin or ciprofloxacin
What can cause Neisseria gonorrhoeae in newborns?
Opthalmoblenorrhoea neonatorum
Which serotype of Haemophilus influenzae can cause invasive infection?
The Haemophilus influenzae with capsule “b” serotype.
How can be prevented the invasive infections caused by Haemophilus influenzae strains?
By Hib vaccine
