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Table 2 Study characteristics

From: Benefits and harms of screening for and treatment of asymptomatic bacteriuria in pregnancy: a systematic review

Comparison study Study design Participants randomised (intervention / control) Treatment regimen Location / Setting / recruitment period Length of follow-up Urine collection / methods used for diagnosis Inclusion and exclusion criteria
Sulphasymazine vs. placebo
Elder [19] RCT, double-blind, parallel 106 (54 / 52) Sulphasymazine 0.5 g/d until birth or onset of pyelonephritis; if bacteriuria persisted medication was changed to nitrofurantoin or tetracycline, dosage not stated  USA / outpatient maternal care / 06 / 1965 – 03 / 1966 Until immediately after birtha Clean voided / UC I: pregnant; same species of bacteria in first 3 uncontaminatedb specimens, ≥ 104 /ml in one and ≥ 105/ml in 2
E: > 32th week of gestation at first examination
Sulphadimethoxine vs. no treatment
Mulla [20] RCT, blinding not stated 100 (50 / 50) Sulphadimethoxine 2 x 250 mg/d 7 days; if bacteriuria persisted treatment was repeated USA / not stated / not stated Until immediately after birtha Catheter (not specified) / UC and “stained smear”c not further specified I: 30th – 32th week of gestation; bacteriuria (not specified)
E: not stated
Sulphadimidine vs. no treatment
Williams [22] RCT, blinding not stated Not stated (85 / 78)d Sulphadimidine 3 x 1 g 7 days; if bacteriuria persisted until 2 to 3 weeks after finishing primary treatment, then nitrofurantoin 2 x 100 mg/d for 7 days if still persisting ampicillin 3 x 250 mg for 7 days GB / maternal care / 1967 10 days post partem Voided midstream / UC I: < 30th week of gestation at recruitment; > 105 g-negative bacteria /ml in ≥ 2 consecutive specimens
E: not stated
Nitrofurantoin vs. placebo
Kazemier [21] Double-blind, placebo-controlled RCT, embedded in a multicentre cohort study 85 (40 / 45) Nitrofurantoin 100 mg 2x/d 5 days, self-administered if follow-up culture positive one week after end of treatment, 1x repeated (masked) medication at the same dose and schedule NL / hospitals and ultrasound centres / 10 / 2011 – 6 / 2013e Until 08 / 2014 Not stated / dip slide with two culture media I: women ≥ 18 years with a singleton pregnancy between 16 and 22 weeks; without symptoms of UTI; ≥ 1x105 CFU /ml of a single microorganism or when 2 different colony types were present but 1 with ≥ 1x105 CFU / ml
E: history of preterm delivery < 34 weeks; warning signs of an imminent preterm delivery; fetal congenital malformations; antibiotic use within 2 weeks of screening; known glucose-6-phosphate dehydrogenase deficiency; hypersensitivity to nitrofurantoin; risk factors for complicated UTI
  1. CFU colony forming units, GB Great Britain, I inclusion criteria, E exclusion criteria, g gram, ml millilitre, NL Netherlands, RCT randomised controlled trial, UC urinary culture, USA United States of America, UTI urinary tract infection
  2. aExact length of follow-up not stated, but outcomes were assessed that occurred immediately after birth
  3. bContamination was defined as a specimen with “large numbers of organisms that were likely to be of vaginal origin”
  4. cThe diagnostic strategy to identify the study population consisted of two different diagnostic tests. No details were reported on the specific catheter, the number of positive test results required, the cut-offs used, or the diagnostic algorithm (i.e., whether both tests were used as a combination and, if so, how the test results were combined to diagnose ASB)
  5. dOf originally 211 pregnant women with gram-negative asymptomatic bacteriuria, a subgroup of participants restricted to those with coliform bacteria was analysed in the relevant trial
  6. eRefers to the entire cohort study