Cystitis accounts for up to 6% of medical visits and is among the main reasons for antibiotic prescriptions in the community. There is growing concern regarding rational antibiotic use, particularly treatment duration and excessive use of fluoroquinolones, as these are associated with increased resistance and adverse events. The objective of this study is to describe the clinical and microbiological profile of recurrent cystitis in the Unified Health System.

Data were collected from electronic medical records of individuals with cystitis treated across the entire healthcare network of São Caetano do Sul, São Paulo, between 01/09/2023 and 30/09/2024. Urine samples were cultured, bacteria were identified by MALDI-TOF and susceptibility determined by disk diffusion. Recurrence of infection was defined as inter-episode intervals >1-month. Variables evaluated included sex, age, comorbidities, total number of episodes and intervals between them, sample source, bacterial frequencies and susceptibility profile per infection episode.

A total of 625 cases were described, 74% female, with a mean age of 69 years. Common comorbidities were diabetes mellitus (51%), hypertension (39%) and dyslipidemia (13%). Twenty-nine percent, 11% and 10% had 2, 3 and 4–9 infection episodes, respectively. Mean intervals between the 1st–2nd, 2nd–3rd and 3rd–4th episodes were 91, 60 and 45 days, respectively. Among 934 urine cultures, 53% were from primary care, 40% from tertiary and 7% from secondary care. In the 1st episode, E. coli and K. pneumoniae accounted for 64% and 15% of isolates, respectively; in the 2nd, 57% and 21%; in the 3rd, 43% and 28%; and in the 4th–9th, 25% and 36%. In the 1st, 2nd and 3rd–6th E. coli episodes, resistance frequencies were: ciprofloxacin (31%, 43%, 51%), sulfamethoxazole-trimethoprim (40%, 46%, 52%), nitrofurantoin (6%, 13%, 2%), ESBL (13%, 15%, 34%) and fosfomycin (0.3%, 2%, 0%). In the 1st, 2nd and 3rd–9th K. pneumoniae episodes: ESBL (26%, 60%, 85%), carbapenem resistance (12%, 21%, 46%), amikacin (11%, 16%, 36%), nitrofurantoin (14%, 40%, 61%) and fosfomycin (11%, 32%, 54%).

The results show that, in recurrent infections, there is increased resistance in E. coli and K. pneumoniae, especially to broad-spectrum antibiotics, reinforcing the need for strategies that promote more judicious use. The findings support fosfomycin or nitrofurantoin as first-line options for cystitis, while discouraging ciprofloxacin use.