Breakthrough Urinary Tract Infections and Antibiotic Resistance Patterns among Patients with Vesicoureteral Reflux on Continuous Antibiotic Prophylaxis in Los Angeles, CA
Zoë Baker, PhD1, Helal Syed, MD2, Scott Sparks, MD2.
1Arizona State University, Tempe, AZ, USA, 2Children's Hospital Los Angeles, Los Angeles, CA, USA.
BACKGROUND: While continuous antibiotic prophylaxis (CAP) reduces the risk of urinary tract infections (UTIs) among patients with vesicoureteral reflux (VUR), breakthrough UTIs (BUTIs) may occur. We aimed to determine the antibiotic resistance patterns and incidence of BUTIs of amongst patients with VUR taking various CAP agents in the Los Angeles area.
Methods: Retrospective chart review identified patients with VUR on CAP who were seen by a pediatric urologist at a single institution in Los Angeles, CA from 2015-2021. Duration of CAP with Sulfamethoxazole/Trimethoprim (SMX/TMP), Cephalexin, and Nitrofurantoin was calculated. Patients with urogenital comorbidities and those who performed intermittent catheterization were excluded. BUTIs were defined as symptomatic and/or febrile positive urine cultures that occurred while the patient was on CAP. Differences in the incidence and resistance patterns of BUTIs by CAP type were compared using the exact Poisson method and Pearson Chi-squared tests.
Results: 402 patients were included. 214 (53%) took SMX/TMP, 188 (47%) took Cephalexin, and 52 (13%) took Nitrofurantoin. 104 patients had at least one BUTI. The incidence rate of BUTIs ranged from 1.51 per 100 person months among patients taking SMX/TMP to 2.52 per 100 person months among patients taking Cephalexin (Table 1). Patients taking Cephalexin were 1.66 times more likely to have a BUTI over the duration of CAP than patients taking SMX/TMP (p=0.001). 77% of UTIs among patients taking SMX/TMP were SMX/TMP-resistant, 48% of BUTIs among patients taking Cephalexin were cephalosporin-resistant, and 12% of BUTIs among patients taking Nitrofurantoin were Nitrofurantoin-resistant (Table 1; p=0.001).
Conclusions: Breakthrough UTIs were significantly more likely to occur among patients taking Cephalexin than those taking SMX/TMP. A large proportion of confirmed BUTIs were SMX/TMP- and cephalosporin-resistant. Patients taking Nitrofurantoin may be less compliant given the high rate of Nitrofurantoin-susceptible organisms seen on culture. These findings may help providers refine their selection of CAP for patients and to reduce rates of BUTIs.
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