Urinary tract infections (UTIs) are common among college-aged women and often recur. Some antibiotics recommended to treat UTIs trigger dysbiosis of intestinal and vaginal microbiomes – where uropathogens originate, though few studies have investigated associations between these therapies with recurrent infections. We retrospectively analysed the electronic medical records of 6651 college-aged women diagnosed with a UTI at a US university student health centre between 2006 and 2014. Women were followed for 6 months for incidence of a recurrent infection. In a secondary analysis, associations in women whose experienced UTI recurrence within 2 weeks were also considered for potential infection relapse. Logistic regression was used to assess associations between infection recurrence or relapse and antibiotics prescribed, in addition to baseline patient characteristics including age, race/ethnicity, region of origin, year of encounter, presence of symptomology, pyelonephritis, vaginal coinfection and birth control consultation. There were 1051 instances of infection recurrence among the 6620 patients, indicating a prevalence of 16%. In the analysis of patient characteristics, Asian women were statistically more likely to experience infection recurrence whereas African American were less likely. No significant associations were identified between the antibiotic administered at the initial infection and the risk of infection recurrence after multivariable adjustment. Treatment with trimethoprim-sulphamethoxazole and being born outside of the USA were significantly associated with increased odds of infection relapse in the multivariate analysis. The results of the analyses suggest that treatment with trimethoprim-sulphamethoxazole may lead to an increased risk of UTI relapse, warranting further study.

The incidence of urinary tract infections (UTIs) is seasonal, and this seasonality may be explained by changes in weather, specifically, temperature. Using data from the Nationwide Inpatient Sample, we identified the geographic location for 581 813 hospital admissions with the primary diagnosis of a UTI and 56 630 773 non-UTI hospitalisations in the United States. Next, we used data from the National Climatic Data Center to estimate the monthly average temperature for each location. Using a case–control design, we modelled the odds of a hospital admission having a primary diagnosis of UTI as a function of demographics, payer, location, patient severity, admission month, year and the average temperature for the admission month. We found, after controlling for patient factors and month of admission, the odds of a UTI diagnosis increased with higher temperatures in a dose-dependent manner. For example, relative to months with average temperatures of 5–7.5 °C, an admission in a month with an average temperature of 27.5–30 °C has 20% higher odds of a primary diagnosis of UTI. However, in months with extremely high average temperatures (above 30 °C), the odds of a UTI admissions decrease, perhaps due to changes in behaviour. Thus, at a population level, UTI-related hospitalisations are associated with warmer weather.

Evidence regarding the seasonality of urinary tract infection (UTI) consultations in primary care is conflicting and methodologically poor. To our knowledge, this is the first study to determine whether this seasonality exists in the UK, identify the peak months and describe seasonality by age. The monthly number of UTI consultations (N = 992 803) and nitrofurantoin and trimethoprim prescriptions (N = 1 719 416) during 2008–2015 was extracted from The Health Improvement Network (THIN), a large nationally representative UK dataset of electronic patient records. Negative binomial regression models were fitted to these data to investigate seasonal fluctuations by age group (14–17, 18–24, 25–45, 46–69, 70–84, 85+) and by sex, accounting for a change in the rate of UTI over the study period. A September to November peak in UTI consultation incidence was observed for ages 14–69. This seasonality progressively faded in older age groups and no seasonality was found in individuals aged 85+, in whom UTIs were most common. UTIs were rare in males but followed a similar seasonal pattern than in females. We show strong evidence of an autumnal seasonality for UTIs in individuals under 70 years of age and a lack of seasonality in the very old. These findings should provide helpful information when interpreting surveillance reports and the results of interventions against UTI.

It has been suggested that mortality is higher in patients admitted to hospitals during the weekend. The objective of this study was to compare outcomes in patients with E. coli urinary tract infection (UTI) depending on the hospital admission day. For this purpose, a secondary analysis of data from a prospective cohort of patients with E. coli UTI was conducted. Weekend diagnosis of UTI was not associated with higher mortality. However, mortality was associated with sepsis, sepsis-induced hypotension and intensive care unit (ICU) admission. Sepsis-induced hypotension and ICU admission were independent determinants of mortality. The results indicate that indicators of severity of illness are associated with higher mortality in patients with UTI rather than the time of diagnosis.

Antibiotic susceptibilities of large cohorts of Enterobacteriaceae isolated from urine collected in the community are scarce. We report the susceptibilities of Enterobacteriaceae isolated from urine of non-selected community populations in a metropolitan area (Leeds and Bradford, UK) over 2 years. Isolates (n = 6614) were identified as follows: Escherichia coli (n = 5436), Klebsiella spp. (n = 525), Proteus mirabilis (n = 305), and 15 other species (n = 290); 58 isolates were unidentified. Ampicillin resistance was observed in 53% E. coli and 28% P. mirabilis; ⩾34% E. coli and P. mirabilis were non-susceptible to trimethoprim compared to 20% Klebsiella spp.; nitrofurantoin resistance was observed in 3% E. coli and 15% Klebsiella spp. The occurrence of extended-spectrum β-lactamases (ESBL) was low (6%), as was non-susceptibility to carbapenems, cefipime and tigecycline (<2%). Further surveillance is required to monitor this level of resistance and additional clinical studies are needed to understand the impact on the outcome of current empirical prescribing decisions.

A systematic review of outbreak and non-outbreak studies of infections caused by extraintestinal pathogenic Escherichia coli (ExPEC) was conducted. This review examines the epidemiology, seasonality, source or mode of transmission, and temporal changes, based on E. coli serogroup, in ExPEC causing sporadic vs. outbreak-associated infections. Twelve outbreak and 28 non-outbreak studies were identified. The existence of ExPEC outbreaks was well supported. Three of four outbreak reports indicated peak periods during the winter months. Serogroups associated with outbreak infections ranged from 1% to 26% (average 11·4%) vs. (range 1–15%, average 3·5%) for serogroups associated with sporadic infections; the distribution of serogroups also differed for outbreak and non-outbreak infections. Study authors indicated that the outbreaks may have resulted from foodborne transmission, but direct evidence was unavailable. This review provides evidence that the epidemiology of endemic vs. epidemic ExPEC infections differs; however, study reporting quality limited epidemiological inferences.