Urinary culture sensitivity after a single empirical antibiotic dose for upper or febrile urinary tract infection: A prospective multicentre observational study

• Published in: Clinical microbiology and infection Vol. 28; no. 8; pp. 1099 - 1104
• Main Authors: John, Gregor, Mugnier, Eric, Pittet, Etienne, Staehli, Dominique Marianne, Clerc, Olivier, Kenfak, Alain Foguena, Konasch, Andreas, Lienhard, Reto, Genné, Daniel
• Format: Journal Article
• Language: English
• Published: 01.08.2022
• ISSN: 1198-743X; 1469-0691
• DOI: 10.1016/j.cmi.2022.02.044

OBJECTIVESUrinary culture sensitivity after antibiotics administration is unknown. This study aimed to describe the diagnostic sensitivity of urine cultures from patients' first, second, and third micturition samples after a single dose of empirical antibiotics given for upper and/or febrile urinary tract infections, as well as searched for factors influencing diagnostic sensitivity over time. METHODSWe collected consecutive urine samples from adult patients with an upper or febrile urinary tract infection diagnosed at four secondary hospital emergency rooms. One sample was collected before a first dose of empirical antibiotic treatment and up to three samples were collected from consecutive postadministration micturition. The main outcome was the number of positive cultures growing uropathogens with ≥103 colony forming units (CFUs) for men and ≥104 for women. Identical analyses were performed for any identified CFU and ≥105 CFU cut-off points. Time between antibiotic administration and first negative urinary culture was noted, which could have been at the time of any of the three postantibiotic urine samples. We used a Cox regression analysis for age- and sex-adjusted analyses. RESULTSA total of 86 of 87 patients' preantibiotic cultures (99%) were positive compared with 26 of 75 (35%; p < 0.001), 15 of 50 (30%; p < 0.001), and 1 of 15 (7%; p < 0.001) of the first, second, and third postantibiotic samples, respectively, and missing 14 of 21 (67%), 13 of 17 (76%), and 7 of 7 (100%) of uropathogens with antibiotic resistance, respectively. The times needed for 25%, 50%, and 75% of cultures to be negative were 1.5, 2.9, and 9 hours, respectively, after antibiotic administration. Older age, male sex, non-Escherichia coli pathogens, urinary tract disease, comorbidity burdens, and urinary catheters prolonged time to negative culture, but were not significantly associated after adjustment. Uropathogens were found at ≥105 CFU in 15 of 75 (20%), 7 of 50 (14%), and 0 of 15 (0%) of the three postantibiotic micturition samples, respectively, and in any identified CFU in 48 of 75 (64%), 23 of 50 (46%), and 1 of 15 (7%), respectively. CONCLUSIONUrinary culture sensitivity decreases rapidly after administering antibiotics.