Antimicrobial Susceptibility ofEscherichia coliin Uncomplicated Cystitis in the Emergency Department: Is the Hospital Antibiogram an Effective Treatment Guide?

Abstract

Objectives: The objective was to compare the rates of antimicrobial susceptibility in strains of Escherichia coli isolated from uncomplicated cystitis cases presenting to the emergency department (ED) of a tertiary care center to those reported on that institution's hospital-wide antibiogram. The hypothesis was that cases of uncomplicated cystitis presenting to the ED will exhibit higher antimicrobial susceptibility than is reported by the hospital-wide antibiogram.Methods: A retrospective chart review of patients who were diagnosed with uncomplicated cystitis in the ED of a large, academic tertiary care center was conducted. Due to an error in the implementation of a new electronic medical record system at this institution in 2009, all urine samples with any abnormality were reflexively sent for culture. The authors were then able to review and record the antibiotic susceptibility patterns of all cultures that grew E. coli. Exclusion criteria included fever, subsequent hospital admission, treatment of suspected pyelonephritis, receiving current cystitis treatment, male sex, indwelling catheters, recent surgery or hospitalization, or asymptomatic for cystitis. Culture isolate antimicrobial susceptibility was then compared with the hospital-wide antibiogram of the same period. Empiric treatment regimens were also recorded as secondary data.Results: Greater susceptibility to trimethoprim-sulfamethoxazole (TMP-SMX; 80% vs. 71%), cefazolin (97% vs. 87%), and ciprofloxacin (89% vs. 73%) was found in our population than was published in the hospital antibiogram. These differences were shown to be statistically significant using Fisher's exact test (p < 0.05). A very high sensitivity to nitrofurantoin (99%), similar to the hospital antibiogram (98%), was also found. Also noted was a high rate of antimicrobial susceptibility when specific empiric treatment was initiated with TMP-SMX or ciprofloxacin: 92 and 89%, respectively. Conclusions:The greater susceptibility of E. coli to TMP-SMX, cefazolin, and ciprofloxacin observed in this population supports the hypothesis that antimicrobial susceptibility rates in uncomplicated cystitis presenting to the ED are greater than those reported in the hospital-wide antibiogram. This could affect treatment guidelines by confirming that antimicrobials currently recommended for use in uncomplicated cystitis are more effective in this setting than currently reported by the hospital-wide antibiogram.ACADEMIC EMERGENCY MEDICINE 2015;22:998-

Emergency Department Urinary Antibiograms Differ by Specific Patient Group

“…Interestingly, we observed lower E. coli susceptibility overall in the ED cohort compared to the institution-wide antibiogram. This finding is in contrast to previous studies in the ED setting in which higher susceptibility rates were noted compared to the institution-wide antibiogram (7)(8)(9). The different patient populations included may have contributed to the differences observed between studies.…”

“…The different patient populations included may have contributed to the differences observed between studies. Other investigators have focused primarily on premenopausal females presenting to the ED with uncomplicated UTI (7,8) or patients with UTI and stable for discharge (9). Our population was comprised of a large proportion of older individuals with a high burden of comorbid conditions, previous antibiotic exposure, and multiple factors predisposing to a more complicated disease process.…”

Changing Antimicrobial Susceptibility Pattern of E. coli Isolated from Urine and Pus Samples

“…In our study, both urine and pus isolates showed only 25% to 35% sensitivity to fluoroquinolones. Tailoring antibiograms and treatment recommendations to better match specific patient populations could improve patient care, simplify treatment regimens, improve antimicrobial stewardship, and reduce health care costs (Christian Smith et al, 2015).…”

Developmental roadmap for antimicrobial susceptibility testing systems

“…Using AST data from single patient isolates recovered from different sources would enable search parameters to include the selection of both specimen type [55][56][57][58][59][60] and specific organisms [59][60][61] , thereby providing more realistic algorithms to guide empiric treatment. Antimicrobial prescription and institutional antibiograms differ between various institutions, sometimes even within an individual health-care institution 60,62,63 , and between inpatient and outpatient populations 60,[63][64][65] . They may change on the basis of length of hospital stay 66 and may depend on the age of the patient 65,67 .…”