Nokea
Microorganisms of various species are often organized into complex communities on a surface and are called __________.
- A. colonies
- B. biofilms
- C. ecosystems
- D. plagues
Correct Answer: B
Rationale: The correct answer is B: biofilms. Biofilms are structured communities of microorganisms that adhere to a surface and are embedded in a matrix. This is the most appropriate term as it specifically describes the organization of various species into complex communities on a surface. Colonies (A) refer to groups of cells of the same species, not necessarily multiple species. Ecosystems (C) are broader systems involving interactions between living organisms and their environment. Plagues (D) are outbreaks of disease, not a term used to describe organized microbial communities.
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Gram (+) bacteria ... MG-ribonucleate and Mg. deoxyribonucleate in:
- A. Proportion 4:1
- B. Proportion 2:1
- C. Proportion 8:1
- D. Proportion 1:1
Correct Answer: A
Rationale: The correct answer is A, proportion 4:1. Gram (+) bacteria have a higher ratio of MG-ribonucleate to Mg. deoxyribonucleate because ribosomal RNA is more abundant in actively growing bacterial cells. This higher proportion of MG-ribonucleate to Mg. deoxyribonucleate is essential for protein synthesis and growth. The other choices are incorrect because they do not reflect the higher ratio of ribosomal RNA to DNA in Gram (+) bacteria, which is crucial for their metabolic activities and cellular functions.
The biosafety level necessary in water testing facilities is level
- A. 1
- B. 2
- C. 3
- D. 4
Correct Answer: A
Rationale: The correct answer is A: 1. Water testing facilities typically handle low-risk microorganisms, hence requiring Biosafety Level 1. BSL 1 is suitable for working with well-characterized agents not known to consistently cause disease in healthy adults. BSL 2 is for moderate-risk agents, BSL 3 for high-risk agents, and BSL 4 for dangerous pathogens. Therefore, choices B, C, and D are incorrect for water testing facilities due to the low risk involved in handling the microorganisms found in water samples.
Sanitary and bacteriological examination of air in drug-store premises revealed increased content of sanitary representative microorganisms. What microorganisms are these?
- A. Golden staphylococcus and hemolytic streptococcus
- B. Diphtheria and tuberculosis bacilli
- C. Colon and blue pus bacilli
- D. Epidermal staphylococcus and sarcina
Correct Answer: A
Rationale: The correct answer is A (Golden staphylococcus and hemolytic streptococcus) because these microorganisms are commonly found in the air of contaminated environments like drug-store premises. Golden staphylococcus and hemolytic streptococcus are pathogenic bacteria associated with infections in humans, indicating poor sanitation. The other choices are incorrect because:
B: Diphtheria and tuberculosis bacilli are not commonly found in the air in drug-store premises.
C: Colon and blue pus bacilli are not typical microorganisms associated with air contamination.
D: Epidermal staphylococcus and sarcina are not likely to be present in high amounts in the air of drug-store premises.
A patient consulted a dentist about itching and burning in the oral cavity; high temperature. The patient was diagnosed with trichomonal gingivostomatitis. What drug should be chosen for his treatment?
- A. Metronidazole
- B. Ampicillin
- C. Gentamicin sulfate
- D. Nystatin
Correct Answer: A
Rationale: Step 1: Trichomonal gingivostomatitis is caused by the parasite Trichomonas tenax.
Step 2: Metronidazole is the drug of choice for treating infections caused by anaerobic organisms like Trichomonas.
Step 3: Metronidazole effectively targets and eliminates Trichomonas parasites in the oral cavity.
Step 4: Therefore, the correct drug choice for treating trichomonal gingivostomatitis is Metronidazole.
Summary:
- Ampicillin (B) is an antibiotic effective against Gram-positive bacteria, not parasites.
- Gentamicin sulfate (C) is an antibiotic used for bacterial infections, not parasitic infections.
- Nystatin (D) is an antifungal medication used for treating fungal infections, not parasitic infections like trichomonal gingivostomatitis.
A patient with fever, chills, and neck stiffness had a cerebrospinal fluid sample with Gram-negative diplococci. What is the likely diagnosis?
- A. Meningococcal meningitis
- B. Pneumococcal meningitis
- C. Haemophilus influenzae meningitis
- D. Listeria monocytogenes meningitis
Correct Answer: A
Rationale: The likely diagnosis is Meningococcal meningitis (Choice A) due to the presence of Gram-negative diplococci in the cerebrospinal fluid. Neisseria meningitidis is a Gram-negative diplococcus commonly associated with meningococcal meningitis. Fever, chills, and neck stiffness are classic symptoms of bacterial meningitis, and Neisseria meningitidis often presents with these symptoms. Pneumococcal meningitis (Choice B) is caused by Streptococcus pneumoniae, a Gram-positive organism. Haemophilus influenzae (Choice C) is also a Gram-negative organism but typically presents with a different clinical picture. Listeria monocytogenes (Choice D) is a Gram-positive rod and is more commonly associated with meningitis in neonates, elderly, and immunocompromised individuals.