Question
A 26 years old pregnant lady presented with fever, dysuria suprapubic pain.
- (a) What is your provisional diagnosis 1 mark(s)
- (b) Enumerate four common bacteria causing this condition 2 mark(s)
- (c) Name two predisposing factors 1 mark(s)
- (d) How do you confirm the diagnosis in the laboratory. e) Name one oral drug for this patient f) What is significant bacteriuria 3 mark(s)
Answer
a) Provisional diagnosis: Urinary tract infection (cystitis, given fever, dysuria, and suprapubic pain) — pregnancy is a recognized risk factor for UTI and a context requiring prompt treatment given the risk of ascending infection/pyelonephritis and adverse pregnancy outcomes.
b) Four common bacteria causing this condition: Escherichia coli (the commonest cause, ~80%), Klebsiella pneumoniae, Proteus mirabilis, and Staphylococcus saprophyticus.
c) Two predisposing factors: Pregnancy (physiological ureteral dilatation/urinary stasis from progesterone-mediated smooth muscle relaxation and mechanical compression by the gravid uterus) and sexual activity (mechanical introduction of periurethral flora into the bladder).
d) Confirmation of diagnosis in the laboratory
- Urine microscopy — pyuria (pus cells) and bacilluria.
- Urine culture — on CLED agar or MacConkey agar, using a calibrated (standard) loop for accurate colony counting; interpreted against Kass’s criterion.
- Dipstick screening — leukocyte esterase and nitrite tests as a rapid presumptive screen.
- Antibiotic sensitivity testing on significant isolates to guide treatment, particularly important in pregnancy where certain antibiotics (e.g., fluoroquinolones, tetracyclines) are contraindicated.
e) One oral drug for this patient: Nitrofurantoin (a first-line, pregnancy-safe agent for uncomplicated UTI, though avoided near term due to theoretical risk of neonatal haemolysis) — alternatively, oral cephalexin (a cephalosporin) is also pregnancy-safe.
f) Significant bacteriuria: defined (Kass’s criterion) as the presence of ≥10⁵ colony-forming units (CFU) per mL of a single bacterial species in a properly collected, clean-catch midstream urine sample — this threshold distinguishes true infection from contamination by periurethral/perineal flora.