Which of the following diarrhoeas is consistently benefited by antimicrobial therapy

Correct Answer: B

Rationale: In the context of chemotherapy drugs, the correct answer to the question is B) Cholera. Cholera is a diarrheal disease caused by the bacterium Vibrio cholerae and is known to be consistently benefited by antimicrobial therapy. Antibiotics can help reduce the duration and severity of cholera symptoms by targeting the bacterial infection directly. Irritable bowel syndrome (A) is a functional gastrointestinal disorder and is not typically treated with antimicrobial therapy. It is managed through dietary changes, stress management, and sometimes medications to control symptoms, but not antibiotics. Salmonella diarrheas (C) are caused by the Salmonella bacteria, which can lead to food poisoning. While antibiotics may be used in severe cases, they are not always necessary and are not consistently recommended as the first-line treatment for all cases of Salmonella infection. Traveller's diarrhoea (D) is usually caused by consuming contaminated food or water in different regions. While antibiotics may be prescribed in some cases, the primary treatment involves rehydration and supportive care. Antimicrobial therapy is not consistently required for all cases of traveller's diarrhoea. In an educational context, understanding the appropriate use of antimicrobial therapy in different types of diarrheal diseases is crucial for healthcare professionals, especially when considering patients undergoing chemotherapy. It is essential to differentiate between bacterial infections like cholera that benefit from antibiotics and other conditions where antimicrobial therapy may not be the first-line or necessary treatment. This knowledge helps in providing effective and appropriate care to patients while minimizing the risk of antibiotic resistance and adverse effects.

Correct Answer: C

Rationale: In the context of chemotherapy drugs, the drug of choice for prophylaxis of meningococcal meningitis during an epidemic is Rifampin (option C). Rifampin is the correct choice because it effectively eradicates carriage of Neisseria meningitidis, the bacteria responsible for meningococcal meningitis, in the nasopharynx. This is crucial during an epidemic to prevent the spread of the disease among close contacts of infected individuals. Phenoxymethyl penicillin (option A) is not the preferred choice for meningococcal prophylaxis due to increasing resistance of Neisseria meningitidis to penicillin. Tetracycline (option B) is not recommended for this purpose because it is not as effective as rifampin. Ciprofloxacin (option D) is also not the first-line choice for prophylaxis of meningococcal meningitis during an epidemic. In an educational context, it is important for students to understand the rationale behind selecting specific drugs for prophylaxis in various infectious disease scenarios. Understanding the mechanism of action and effectiveness of each drug can help healthcare professionals make informed decisions in real-world situations to prevent disease transmission and promote public health.

Correct Answer: C

Rationale: In the context of chemotherapy drugs, specifically trimethoprim, sulfamethoxazole, and their combination cotrimoxazole, understanding their effectiveness in various conditions is crucial. The correct answer is C) Pneumocystis carinii pneumonia. Pneumocystis carinii pneumonia is a fungal infection commonly seen in immunocompromised individuals, such as those with HIV/AIDS. Trimethoprim and sulfamethoxazole individually may not be effective against this particular infection. However, when used in combination as cotrimoxazole, they synergistically target different stages of the fungal life cycle, resulting in an effective treatment for Pneumocystis carinii pneumonia. Option A) Prostatitis and Option D) Bacillary dysentery are bacterial infections, not fungal, and are typically treated with antibiotics that target specific bacterial mechanisms, making trimethoprim and sulfamethoxazole less effective for these conditions. Option B) Lymphogranuloma venereum is a sexually transmitted infection caused by Chlamydia trachomatis, which is treated with antibiotics like doxycycline or azithromycin, not trimethoprim or sulfamethoxazole. Understanding the specific mechanisms of action and indications for different chemotherapy drugs is essential in providing effective treatment for patients with various infections, highlighting the importance of knowing when combination therapies like cotrimoxazole are necessary for optimal outcomes.

Correct Answer: C

Rationale: In this scenario, the correct answer is C) Nitrofurantoin. Nitrofurantoin is a drug that attains therapeutic antibacterial concentration specifically in the urinary tract, making it effective for treating urinary tract infections (UTIs). This drug is primarily eliminated via the kidneys into the urine, allowing it to concentrate in the urinary tract and target bacteria effectively while minimizing systemic exposure. Option A) Sulfasomidine is a sulfonamide antibiotic that can achieve therapeutic concentrations in various tissues, not just the urinary tract. It is used to treat a wide range of bacterial infections but does not specifically target the urinary tract like nitrofurantoin. Option B) Piperacillin is a broad-spectrum antibiotic that is effective against a wide range of bacterial infections but does not concentrate specifically in the urinary tract like nitrofurantoin. Option D) Both (b) and (c) is incorrect because piperacillin, like sulfasomidine, does not target the urinary tract specifically for treatment. From an educational perspective, understanding the pharmacokinetics and tissue distribution of chemotherapy drugs is crucial for healthcare professionals. Knowing which drugs are more likely to concentrate in specific tissues, like the urinary tract in the case of nitrofurantoin, can help in selecting the most appropriate medication for treating infections effectively while minimizing side effects and resistance development. This knowledge is vital for clinical decision-making and providing optimal patient care.

Correct Answer: B

Rationale: In the context of chemotherapy drugs for tuberculosis, the correct answer is B) Rifampin. Rifampin is effective against intermittently multiplying (spurter) tubercle bacilli due to its unique mechanism of action, which involves inhibiting bacterial RNA synthesis. This is particularly effective against bacteria in low-oxygen conditions, such as those found within caseous material in the lungs where the tubercle bacilli reside. Ethambutol (A) targets cell wall synthesis and is not as effective against the bacilli in low-oxygen environments. Streptomycin (C) interferes with protein synthesis and is more effective against actively multiplying bacteria rather than intermittently multiplying ones. Pyrazinamide (D) is most effective at acidic pH levels, which are not typically found in caseous material. Understanding the susceptibility of different chemotherapy drugs to specific conditions and stages of bacterial growth is crucial in effectively treating tuberculosis. By knowing the mechanisms of action of each drug, healthcare providers can tailor treatment regimens to target the bacteria at their most vulnerable points, ultimately improving patient outcomes and reducing the development of drug resistance.