Urinary tract infections (UTI) are the most common infectious complication after kidney transplant. Previous research at our center showed sulfamethoxazole/trimethoprim (SMX/TMP) use for PCP prophylaxis did not add the benefit of reducing the frequency of UTIs. The aim of our study was to determine if the addition of cephalexin reduces UTI rates after renal transplant.

Methods: From 9/2014 to 11/2015 (new era), UTI rates among kidney transplant recipients treated with cephalexin for 1 month with or without SMX/TMP PCP prophylaxis were compared to recipients transplanted from 1/2007 to 12/2012 (old era) who were treated with or without SMX/TMP PCP prophylaxis alone. A low dose fluoroquinolone was used in patients with a cephalosporin allergy. A UTI was defined as a urine culture containing >10⁴ CFU/ml with a positive urinalysis. An exact chi-square test was used to compare UTI rates within the first 3 months post-transplant. A Wilcoxon rank sum test was used to compare days to UTI.

Results:

A total of 661 patients from the old era and 151 patients from the new era were evaluated. 12 patients in the new era received a fluoroquinolone (8 in the SMX/TMP group, 4 in no SMX/TMP group). The total UTI incidence rate in the new era (11.3%) was lower than in the old era (17.5%) but failed to reach statistical significance (p=0.067). In the new era there was significantly lower UTI rate in patients taking SMX/TMP vs. those who did not (7.5% vs. 25.8%, p=0.008). New era SMX/TMP patients also had a significantly lower incidence rate of UTI vs. SMX/TMP patients in the old era (7.5% vs. 16.3%, p=0.021). Median (IQR) time to development of UTI was significantly longer in the new era (34 (15-50) days vs. 14 (7-34) days, p=0.012). Enterococcus sp. and e. coli were the most common bacteria causing UTIs during both eras.

Conclusion: There was a significant decrease in UTI rates among patients treated with cephalexin in addition to SMX/TMP PCP prophylaxis compared to patients treated with SMX/TMP alone, however this benefit was lost when an alternative PCP prophylactic was used.

CITATION INFORMATION: Klem P, Gralla J, Chang D, Wiseman A, Davis S, Cooper J. Antibiotic Prophylaxis Against Urinary Tract Infections After Renal Transplant. Am J Transplant. 2017;17 (suppl 3).

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