Poor clinical outcomes associated with community-onset urinary tract infections due to extended-spectrum cephalosporin-resistant Enterobacteriaceae.

OBJECTIVE: Resistance to extended-spectrum cephalosporins (ESC) among Enterobacteriaceae (EB) is increasingly prevalent. We sought to determine the clinical outcomes associated with community-onset ESC-resistant (ESC-R) EB urinary tract infections (UTIs) in a US health system. DESIGN: Retrospective cohort study.PatientsAll patients presenting to the emergency departments (EDs) or outpatient practices with EB UTIs between 2010 and 2013 were included. Exposed patients had ESC-R EB UTIs. Unexposed patients had ESC-susceptible EB UTIs and were matched to exposed subjects 1:1 on study year. Multivariable logistic regression analyses were performed to evaluate the association between ESC-R EB UTI and the outcomes of clinical failure and inappropriate initial antibiotic therapy (IIAT). RESULTS: A total of 302 patients with community-onset EB UTI were included, with 151 exposed and unexposed. On multivariable analyses, UTI due to an ESC-R EB was significantly associated with clinical failure (odds ratio [OR], 7.07; 95% confidence interval [CI], 3.16-15.82; P<.01). Other independent risk factors for clinical failure included infection with Citrobacter spp and need for hemodialysis. UTI due to an ESC-R EB was also significantly associated with IIAT (OR, 4.40; 95% CI, 2.64-7.33; P<.01). CONCLUSIONS: Community-onset UTI due to an ESC-R EB organism is significantly associated with clinical failure, which may be due in part to IIAT. Further studies are needed to determine which patients in the community are at high risk for drug-resistant infection to help inform prompt diagnosis and appropriate antibiotic prescribing for ESC-R EB.

High fluoroquinolone MIC is associated with fluoroquinolone treatment failure in urinary tract infections caused by fluoroquinolone susceptible Escherichia coli.

BACKGROUND: Suboptimal clinical response to fluoroquinolone (FQ) therapy has been clearly documented in patients with Salmonella typhi infection with reduced FQ susceptibility. However, the clinical impact of reduced FQ susceptibility on other infections including E. coli urinary tract infections (UTIs) has never been evaluated. METHODS: We conducted a retrospective cohort study of female patients with fluoroquinolone susceptible E. coli (FQSEC) UTIs who received FQ therapy at outpatient services within University of Pennsylvania Health System, Philadelphia. Exposed patients were those with high MIC-FQSEC UTIs (the levofloxacin MIC > 0.12 but ≤ 2 mg/L) while unexposed patients were those with low MIC-FQSEC UTIs (the levofloxacin MIC ≤ 0.12 mg/L). The primary treatment outcome was treatment failure within 10 weeks after initiation of FQ therapy. RESULTS: From May 2008 to April 2011, we enrolled 29 exposed patients and 246 unexposed patients. Two patients in each group experienced treatment failure; exposed vs. unexposed (6.9 vs. 0.8%; p = 0.06). Risk difference and risk ratio (RR) for treatment failure were 0.06 [95% CI -0.03-0.15; exact-p = 0.06] and 8.48 [95% CI 1.24-57.97; exact-p = 0.06], respectively. After adjusting for underlying cerebrovascular disease, the RR was 7.12 (95% CI 1.20-42.10; MH-p = 0.04). CONCLUSION: Our study demonstrated the negative impact of reduced FQ susceptibility on the treatment response to FQ therapy in FQSEC UTIs. This negative impact may be more intensified in other serious infections. Future studies in other clinical situations should be conducted to fill the gap of knowledge.

Clinical and molecular epidemiology of Escherichia coli sequence type 131 among hospitalized patients colonized intestinally with fluoroquinolone-resistant E. coli.

This study examined molecular and epidemiologic factors associated with Escherichia coli sequence type 131 (ST131) among hospitalized patients colonized intestinally with fluoroquinolone (FQ)-resistant E. coli between 2002 and 2004. Among 86 patients, 21 (24%) were colonized with ST131. The proportion of ST131 isolates among colonizing isolates increased significantly over time, from 8% in 2002 to 50% in 2004 (P = 0.003). Furthermore, all 19 clonally related isolates were ST131. Future studies should identify potential transmissibility differences between ST131 and non-ST131 strains.

Comparison of unit-specific and hospital-wide antibiograms: potential implications for selection of empirical antimicrobial therapy.

OBJECTIVE: To identify differences between unit-specific and hospital-wide antibiograms and to determine the potential impact of these differences on selection of empirical antimicrobial therapy. SETTING: A 625-bed tertiary care medical center. METHODS: Antimicrobial susceptibility results were collected for all inpatient clinical bacterial isolates recovered over a 3-year period; isolates were categorized by the hospital location of the patient at the time of sampling and by the anatomic site from which the isolate was recovered. Antibiograms from each unit were compiled for the most commonly isolated organisms and were compared to the hospital-wide antibiogram. RESULTS: A total of 9,970 bacterial isolates were evaluated in this study, including 2,646 enterococcal isolates, 2,806 S. aureus isolates, 2,795 E. coli isolates, and 1,723 Pseudomonas aeruginosa isolates. The percentages of bacterial isolates resistant to antimicrobials were significantly higher in the medical ICU and surgical ICU than the hospital-wide antibiogram would have predicted, whereas the percentages of isolates susceptible to antimicrobials were significantly higher in the non-ICU units, compared with the hospital overall. However, on general medicine units, the prevalence of susceptibility to levofloxacin was significantly lower than that for the hospital overall. CONCLUSIONS: Unit-specific antibiograms are important for making informed decisions about empirical antimicrobial therapy, because the hospital-wide antibiogram may mask important differences in susceptibility rates across different units. These differences may have important implications for selecting the optimal empirical antimicrobial therapy.

Identification of optimal combinations for empirical dual antimicrobial therapy of Pseudomonas aeruginosa infection: potential role of a Combination Antibiogram.

To better determine the optimal combinations for empirical dual antimicrobial therapy of Pseudomonas aeruginosa infection, we evaluated the utility of a novel combination antibiogram. Although the combination antibiogram allowed modest fine-tuning of choices for dual antibiotic therapy, selections based on the 2 antibiograms did not differ substantively. Drug combinations with the broadest coverage were consistently composed of an aminoglycoside and a beta-lactam.

Increasing fluoroquinolone resistance in Campylobacter jejuni, Pennsylvania, USA,1982-2001.

Fluoroquinolone-resistant Campylobacter jejuni has been observed worldwide and is now being seen in the United States. Among patients in our health-care system in Pennsylvania, fluoroquinolone-resistant C. jejuni were not observed from 1982 to 1992; however, resistance increased to 40.5% in 2001. Resistance to erythromycin remains at a low level (<5%).