JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD Pharm. D III Year PHARMACOTHERAPEUTICS - II Previous Question Paper (November/December - 2021 - R08)

Urinary tract infections (UTIs) occur when microorganisms, primarily bacteria, colonize the urinary tract. The etiopathogenesis involves the interplay between bacterial virulence factors and host defense mechanisms.

1. Pathogens: Escherichia coli is the most common causative agent (80-90%), followed by Staphylococcus saprophyticus, Klebsiella, and Proteus species.
2. Route of Infection: The ascending route is the most frequent, where periurethral bacteria migrate into the bladder. Hematogenous spread is rare and usually associated with systemic infections.
3. Virulence Factors: Uropathogenic E. coli (UPEC) utilize P-fimbriae to adhere to urothelial receptors, preventing bacterial clearance during micturition.
4. Host Factors: Normal host defenses include the flushing action of urine, low urinary pH, high osmolality, and the presence of Tamm-Horsfall protein. Obstruction (e.g., stones, prostatic hypertrophy), incomplete bladder emptying, and vesicoureteral reflux significantly increase susceptibility by allowing bacterial stasis and proliferation.
5. Inflammation: Bacterial adherence triggers an inflammatory response, leading to the recruitment of neutrophils and the release of cytokines, resulting in the clinical symptoms of cystitis or pyelonephritis.

Gonorrhoea and Syphilis are sexually transmitted infections (STIs) caused by distinct bacterial pathogens with specific mechanisms of pathogenesis.

1. Gonorrhoea: Caused by Neisseria gonorrhoeae, a Gram-negative diplococcus. It attaches to non-ciliated columnar epithelial cells via pili and opacity proteins. The bacteria invade the subepithelial space, triggering a massive influx of neutrophils, which leads to the characteristic purulent discharge. If untreated, it can ascend to cause pelvic inflammatory disease (PID) or disseminate into the bloodstream.
2. Syphilis: Caused by the spirochete Treponema pallidum. Transmission occurs through direct contact with infectious lesions. The organism penetrates intact mucous membranes or microscopic skin abrasions.
3. Stages of Syphilis: The primary stage is characterized by the formation of a painless chancre at the site of inoculation due to local inflammation and endarteritis. The bacteria then disseminate hematogenously. The secondary stage involves systemic manifestations like rashes and lymphadenopathy due to widespread immune complex deposition. The tertiary stage, occurring years later, involves chronic granulomatous inflammation (gummas) and cardiovascular or neurosyphilis, resulting from persistent infection and delayed hypersensitivity reactions.