· Training test in medical microbiology ·
- Streptococcus pneumoniae is considered susceptible when penicillin MIC is:
- 0.5 mg/l
- 0.006 mg/l
- 2 mg/l
- 8 mg/l
Look at the picture of an agar plate inoculated with a bacterium; two antibiotic disks are laid on the surface. The plate was inoculated with a pure culture of the bacterium.

- The growh around the disks may show :
- Small colony-variants of susceptible cells
- Colonies of cells with higher susceptibility grown from the a mixed culture
- Mixed inoculum consisting of a susceptible strainX and a different resistant strain Y.
- None of the above
- The phenomenon shown above may be explained also by:
- Two different populations of cells
- Heteroresistance
- Improper technique
- None of the above
- The phenomenon is typical and is very often encountered if the examined strain is:
- Streptococcus pneumoniae and the disks contains gentamicin
- Streptococcus pyogenes and the disks contains ampicillin
- Staphylococcus aureus and the disks contains oxacillin
- Staphylococcu epidermidis and the disks contains methicillin
- Mechanism of resistance to macrolides is explained:
- by mutation in the gene detremining gyrase
- Acetylation of the antibiotic
- Modification of ribosomes
- Impaired permeability
- Chromosomal mutation causes resistance to:
- Beta lactams in pneumococci
- Macrolides in E.coli
- Amikacin in Klebsiella pneumoniae
- Gentamicin in Enterococcus faecalis
- Which of the following is the most common cause of atypical pneumonia?
- Streptococcus pneumoniae
- Mycoplasma pneumoniae
- Mycobacterium tuberculosis
- Klebsiella pneumoniae
- Staphylococcus aureus
- In amebiasis, what is the chief site of extraintestinal disease?
- Liver
- Spleen
- Gall bladder
- Bile duct
- Skin
- Which of the following is a common protozoan cause of pneumonia in AIDS patients?
- Mycoplasma pneumoniae
- Candida albicans
- Paragonimus westermanni
- Pneumocystis carinii
- Aspergillus niger
- Negri bodies are a pathognomonic sign of
- Fungal meningitis
- Rabies
- Tubercular meningitis
- Herpesvirus encephalitis
- Tetanus
- Which of the following is the most common cause of pelvic inflammatory disease (PID)?
- Mycoplasma hominis
- Actinomyces israelii
- Chlamydia trachomatis
- Escherichia coli
- Treponema pallidum
- Which is the most efficacious penicillin for the treatment of Pseudomonas infections?
- Ampicillin
- Ticarcillin
- Amoxicillin
- Penicillin G
- Penicillin V
- Which of the following causes of pneumonia may result in bradycardia, vomiting, diarrhea, and mental confusion?
- Chlamydia pneumoniae
- Mycoplasma pneumoniae
- Streptococcus pneumoniae
- Legionella pneumophila
- Adenovirus
Correct answers

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