MI8.{1-2,4} | Genitourinary & Sexually Transmitted Infections — Glossary

UTI occurring in a patient with an indwelling urinary catheter; the most common hospital-acquired infection; biofilm formation on catheter is the key pathogenic mechanism.

The painless, indurated (firm), clean-based ulcer of primary syphilis that appears 3–4 weeks after Treponema pallidum inoculation; accompanied by painless regional lymphadenopathy.

Cystine Lactose Electrolyte Deficient agar — the standard culture medium for urine; suppresses Proteus swarming and differentiates lactose fermenters from non-fermenters.

Microscopy technique using oblique illumination to visualise unstained spirochaetes (Treponema pallidum) from primary syphilitic chancre exudate, seen as bright corkscrew-motile organisms.

The infectious, metabolically inert, extracellular form of Chlamydia that is taken up by host cells.

A recurrent STI caused predominantly by HSV-2; characterised by grouped vesicles and painful ulcers on genitalia; virus remains latent in sacral dorsal root ganglia between episodes.

Viral proteins of high-risk HPV types that inactivate the tumour suppressors p53 (E6) and pRb (E7) respectively, driving uncontrolled cell proliferation and cervical carcinogenesis.

A squamous epithelial cell showing the cytopathic effect of HPV infection — perinuclear cytoplasmic clearing (halo) with a wrinkled, raisinoid nucleus; identified on Pap smear.

An STI caused by Chlamydia trachomatis serovars L1–L3; characterised by a transient primary genital ulcer followed by painful inguinal buboes (lymphadenopathy); can cause rectal disease in MSM.

Conjunctivitis in a neonate occurring within the first 28 days of life; caused by Neisseria gonorrhoeae or Chlamydia trachomatis acquired during delivery; can cause blindness if untreated.

Adhesins on uropathogenic E. coli (UPEC) that bind P blood group antigens on renal tubular cells; a key virulence factor for ascending pyelonephritis.

The intracellular, metabolically active, replicating form of Chlamydia inside host cell endosomes; reorganises into elementary bodies for release.

Colony counts indicating true infection rather than contamination: ≥10⁵ CFU/mL on mid-stream urine; ≥10³ CFU/mL on catheter specimen; any growth on suprapubic aspiration.

Presence of white blood cells (pyuria) in urine with no growth on routine bacterial culture; classic presentation of genitourinary tuberculosis; also occurs in chlamydial urethritis and analgesic nephropathy.

Urinary stones composed of magnesium ammonium phosphate formed when urease-producing bacteria (especially Proteus mirabilis) hydrolyse urea to ammonia, raising urine pH and promoting mineral precipitation; can grow into staghorn calculi.

A public health approach to STI treatment in which antibiotics targeting the most common causative organisms for a clinical syndrome (e.g., urethral discharge) are administered without microbiological confirmation; used by NACO at PHC level in India.

Selective chocolate agar containing vancomycin, colistin, and nystatin used to culture Neisseria gonorrhoeae; suppresses normal flora while allowing fastidious gonococcal growth.

A treponemal-specific confirmatory test for syphilis; detects antibodies against T. pallidum antigens; remains positive for life after infection, regardless of treatment.

A pear-shaped flagellated protozoan STI pathogen causing frothy yellow-green vaginal discharge and strawberry cervix in women; usually asymptomatic in men; diagnosed by wet mount showing motile organisms.

A rapid microscopy preparation from the base of a herpetic vesicle stained with Giemsa or Wright stain; shows multinucleated giant cells characteristic of HSV or VZV infection.

Microbial invasion and multiplication within the urinary tract; classified as lower (cystitis, urethritis) or upper (pyelonephritis); confirmed by significant bacteriuria on urine culture.

Venereal Disease Research Laboratory test — a non-treponemal flocculation test that detects anti-cardiolipin antibodies (reagin); used for syphilis screening; titres reflect disease activity and fall with treatment.