Original Research
Urologist Workforce Variation Across the VHA
Distribution of urologists varies significantly at the facility rather than at the regional level, according to a large-scale study, but regional...
Results
This study included 20 positive urine cultures for ampicillin-resistant E faecium in 19 subjects. Nine cases were treated with amoxicillin, and 11 cases were treated with nitrofurantoin. At baseline, the mean age was 75 years, mean duration of therapy was 14 days, and all the subjects were male. The baseline characteristics of the 2 groups were similar with the exception of an older population, shorter duration of therapy, and increased incidence of chronic kidney disease in the amoxicillin treatment group, P = .02, .03, and .01, respectively.
Symptoms were documented in 8 of 9 (89%) cases at the time of the positive culture in the amoxicillin treatment group and 5 of 11 (45%) cases in the nitrofurantoin treatment group (Table). The asymptomatic amoxicillin treatment group case and 5 of the 6 nitrofurantoin treatment group asymptomatic cases received treatment prior to a urologic procedure in accordance with the Infectious Diseases Society of America (IDSA) guidelines for the treatment of asymptomatic bacteriuria. The urologic procedures included transurethral resection of a bladder tumor, cystoscopy, urethral dilation, cystometrogram, and transurethral resection of the prostate. One asymptomatic subject in the nitrofurantoin group did not have any documentation to support an appropriate indication for treatment. All positive cultures were > 100,000 colonies/mL except for 1 culture in the nitrofurantoin treatment group, which was 45,000 colonies/mL, but because the subject was symptomatic, treatment was administered and a repeat urine culture was negative.
There were 8 cases classified as cure, 1 presumed cure, and no failures in the amoxicillin group. In the nitrofurantoin group, 7 cases were classified as cure, 1 presumed cure, and 3 failures. The presumed cures were excluded from the statistical analysis due to inability to ensure these cases were truly cured. Also excluded from the statistical analysis was one of the failures in the nitrofurantoin group, because the subject was asymptomatic with no known indication for treatment. This left 8 cases classified as cure and no failures in the amoxicillin group compared with 7 cases classified as cure and 2 failures in the nitrofurantoin group, P = .47 (Figure). Statistical analysis was performed using the Fisher exact test.
Discussion
There was no statistically significant difference between amoxicillin and nitrofurantoin for the treatment of ampicillin-resistant E faecium UTIs. There were no failures in the amoxicillin group despite all isolates displaying resistance based on current breakpoints, supporting the theory that higher urine concentrations of amoxicillin may overcome the MIC of resistant isolates.
Related: Novel Therapy for Treating Complicated UTIs
Of the 11 cases treated with nitrofurantoin, 3 were classified failures. The first failure in the nitrofurantoin group was an asymptomatic subject who did not have a repeat urine culture but had a repeat UA, which showed a persistent elevation in WBC and leukocyte esterase count. This subject was removed from the statistical analysis, as treatment was not indicated per IDSA guidelines. No reason could be identified for the second failure, as a repeat culture demonstrated continued presence of E faecium. Chronic kidney disease (CKD) contributed to the third failure in the nitrofurantoin treatment group; the subject’s CrCl was about 17 mL/min. After treatment, the subject had a repeat urine culture, which indicated the continued presence of E faecium. The subject was later successfully treated with amoxicillin. Both cultures in the same subject were included in the final analysis per protocol, as the subject had an adequate evaluation of efficacy between courses. Four additional cases with CKD were treated with nitrofurantoin; however, their CrCl ranged from 40 to 55 mL/min, and all were classified cure or presumed cure.
Limitations
There were several limitations to this study. Due to the strict inclusion and exclusion criteria, a limited number of subjects were evaluated. Given that this was a retrospective study, it is possible that symptoms were reported by a subject but not appropriately documented. Another significant limitation of this trial was that MICs were not determined due to the retrospective nature of the study. External validity was also limited due to a predominately elderly and male population. Safety data regarding different therapies were not collected, as this study evaluated only the efficacy of therapies.