Urinary Tract Infections due to Multidrug-Resistant Enterobacteriaceae: Prevalence and Risk Factors in a Chicago Emergency Department

Clinical Management of an Increasing Threat: Outpatient Urinary Tract Infections Due to Multidrug-Resistant Uropathogens

Urinary tract infections (UTIs) are among the most commonly treated bacterial infections. Over the past decade, antimicrobial resistance has become an increasingly common factor in the management of outpatient UTIs. As treatment options for multidrug-resistant (MDR) uropathogens are limited, clinicians need to be aware of specific clinical and epidemiological risk factors for these infections. Based on available literature, the activity of fosfomycin and nitrofurantoin remain high for most cases of MDR Escherichia coli UTIs. Trimethoprim-sulfamethoxazole retains clinical efficacy, but resistance rates are increasing internationally. Beta-lactam agents have the highest rates of resistance and lowest rates of clinical success. Fluoroquinolones have high resistance rates among MDR uropathogens and are being strongly discouraged as first-line agents for UTIs. In addition to accounting for local resistance rates, consideration of patient risk factors for resistance and pharmacological principles will help guide optimal empiric treatment of outpatient UTIs.

Etiology and antibiotic susceptibility of bacterial pathogens responsible for community-acquired urinary tract infections in Poland

Urinary tract infections (UTIs) are some of the most common infections in both community and hospital settings infections. With their high rate of incidence, recurrence, complications, diverse etiologic agents, as well as growing antibiotic resistance, UTIs have proven to be a serious challenge for medical professionals. The aim of this study was to obtain data on the susceptibility patterns of pathogens responsible for UTIs in Poland to currently used antibiotics. A total of 396 bacterial isolates were collected between March and May 2013 from 41 centers in all regions of Poland. The majority of isolates were from adult patients (96.2 %); 144 (37.8 %) patients were diagnosed with uncomplicated UTI, while the remaining 237 (62.2 %) had a complicated infection. The most prevalent pathogen was Escherichia coli (71.4 %), followed by Klebsiella spp. (10.8 %) and the Proteae group (7.6 %). Escherichia coli was responsible for 80.6 % of cases of uncomplicated and 65.8 % of complicated infections. Only 65.8 % of E. coli isolates were susceptible to ciprofloxacin (uncomplicated 75.9 %, complicated 58.3 %), 64.0 % to nitrofurantoin (67.2 %, 62.8 %), 65.1 % to trimethoprim/sulfamethoxazole (68.1 %, 62.8 %), and 66.4 % to fosfomycin (77.6 %, 62.2 %). Among E. coli isolates from all UTIs, only 43.4 % were susceptible to ampicillin, with 47.4 % from uncomplicated compared with 40.4 % from complicated infections; 88.2 % to amoxicillin/clavulanic acid (91.4 % vs. 85.9 % complicated); 90.1 % to cefuroxime (93.1 %, 87.8 %); and 94.1 % to cefotaxime (98.2 %, 91.0 %). Thirty-five strains (10.4 %) were capable of producing extended-spectrum β-lactamases (ESBLs). This study demonstrates an increase in multidrug-resistant strains, especially among the leading pathogens associated with UTIs, including E. coli, Klebsiella spp., and Proteus spp.

Urinary Squamous Epithelial Cells Do Not Accurately Predict Urine Culture Contamination, but May Predict Urinalysis Performance in Predicting Bacteriuria

OBJECTIVES

The presence of squamous epithelial cells (SECs) has been advocated to identify urinary contamination despite a paucity of evidence supporting this practice. We sought to determine the value of using quantitative SECs as a predictor of urinalysis contamination.

METHODS

Retrospective cross-sectional study of adults (≥18 years old) presenting to a tertiary academic medical center who had urinalysis with microscopy and urine culture performed. Patients with missing or implausible demographic data were excluded (2.5% of total sample). The primary analysis aimed to determine an SEC threshold that predicted urine culture contamination using receiver operating characteristics (ROC) curve analysis. The a priori secondary analysis explored how demographic variables (age, sex, body mass index) may modify the SEC test performance and whether SECs impacted traditional urinalysis indicators of bacteriuria.

RESULTS

A total of 19,328 records were included. ROC curve analysis demonstrated that SEC count was a poor predictor of urine culture contamination (area under the ROC curve = 0.680, 95% confidence interval [CI] = 0.671 to 0.689). In secondary analysis, the positive likelihood ratio (LR+) of predicting bacteriuria via urinalysis among noncontaminated specimens was 4.98 (95% CI = 4.59 to 5.40) in the absence of SECs, but the LR+ fell to 2.35 (95% CI = 2.17 to 2.54) for samples with more than 8 SECs/low-powered field (lpf). In an independent validation cohort, urinalysis samples with fewer than 8 SECs/lpf predicted bacteriuria better (sensitivity = 75%, specificity = 84%) than samples with more than 8 SECs/lpf (sensitivity = 86%, specificity = 70%; diagnostic odds ratio = 17.5 [14.9 to 20.7] vs. 8.7 [7.3 to 10.5]).

CONCLUSIONS

Squamous epithelial cells are a poor predictor of urine culture contamination, but may predict poor predictive performance of traditional urinalysis measures.

Multidrug resistant Enterobacteriaceae and extended spectrum β-lactamase producing Escherichia coli: a cross-sectional study in National Kidney Center, Nepal

Background

Emergence of antibacterial resistance and production of Extended spectrum β-lactamases (ESBLs) are responsible for the frequently observed empirical therapy failures. Most countries have experienced rapid dissemination of ESBLs producing Enterobacteriaceae isolates, particularly E. coli and Klebsiella pneumoniae. ESBLs are clinically significant and when detected, indicate the need for the use of appropriate antibacterial agents. But antibacterial choice is often complicated by multi-resistance.

Methods

This study was carried from June to November 2014 to study the multidrug resistant (MDR) Enterobacteriaceae and ESBL producing E. coli among urine isolates in hospital setting. Isolates from urine samples were primarily screened for possible ESBL production followed by phenotypic confirmation. Antibiotic susceptibility testing (AST) was done by Kirby Bauer disk diffusion method following Clinical and Laboratory Standard Institute (CLSI) guidelines.

Results

Out of 450 urine samples processed, 141 significant growths were obtained including 95 Enterobacteriaceae isolates with 67 E. coli. Among Enterobacteriaceae, 92 (96.84 %) were recorded as MDR and 18 (26.87 %) E. coli were confirmed as ESBLs producers.

Conclusions

Using the phenotypic confirmatory test forwarded by the CLSI, relatively significant E. coli isolates tested were ESBL producers. Also high numbers of MDR organisms were isolated among Enterobacteriaceae. Isolates showed significant resistance to the commonly prescribed drugs. These findings suggest for further study in this field including the consequences of colonization with MDR and ESBL-producing bacteria both in the community and in the hospital setting.

Two Simple Rules for Improving the Accuracy of Empiric Treatment of Multidrug-Resistant Urinary Tract Infections

The emergence of multidrug-resistant (MDR) uropathogens is making the treatment of urinary tract infections (UTIs) more challenging. We sought to evaluate the accuracy of empiric therapy for MDR UTIs and the utility of prior culture data in improving the accuracy of the therapy chosen. The electronic health records from three U.S. Department of Veterans Affairs facilities were retrospectively reviewed for the treatments used for MDR UTIs over 4 years. An MDR UTI was defined as an infection caused by a uropathogen resistant to three or more classes of drugs and identified by a clinician to require therapy. Previous data on culture results, antimicrobial use, and outcomes were captured from records from inpatient and outpatient settings. Among 126 patient episodes of MDR UTIs, the choices of empiric therapy against the index pathogen were accurate in 66 (52%) episodes. For the 95 patient episodes for which prior microbiologic data were available, when empiric therapy was concordant with the prior microbiologic data, the rate of accuracy of the treatment against the uropathogen improved from 32% to 76% (odds ratio, 6.9; 95% confidence interval, 2.7 to 17.1; P < 0.001). Genitourinary tract (GU)-directed agents (nitrofurantoin or sulfa agents) were equally as likely as broad-spectrum agents to be accurate (P = 0.3). Choosing an agent concordant with previous microbiologic data significantly increased the chance of accuracy of therapy for MDR UTIs, even if the previous uropathogen was a different species. Also, GU-directed or broad-spectrum therapy choices were equally likely to be accurate. The accuracy of empiric therapy could be improved by the use of these simple rules.

Differential characteristics of healthcare-associated compared to community-acquired febrile urinary tract infections in males

The objective of this study was to analyse the characteristics of healthcare-associated febrile urinary tract infection (HCA-FUTI) compared to community-acquired FUTI (CA-FUTI) in men. An ambispective cross-sectional study in which we recorded clinical and microbiology data and outcomes from males with FUTI attended in the Emergency Department was carried out. A total of 479 males with FUTI, 162 (33.8%) HCA-FUTI and 317 (66.2%) CA-FUTI, were included. HCA-FUTI patients were older (p < 0.001), had higher Charlson scores (p < 0.001) and received previous antimicrobial treatment more frequently (p < 0.001) compared to CA-FUTI patients. HCA-FUTI was less likely caused by Escherichia coli (p < 0.001) and more frequently by Klebsiella spp. (p = 0.02), Enterobacter spp. (p < 0.001) and Pseudomonas aeruginosa (p < 0.001). Resistance to ceftriaxone (p = 0.006), gentamicin (p < 0.001), quinolones (p < 0.001), co-trimoxazole (p = 0.001) and fosfomycin (p = 0.009) was higher among E. coli strains isolated from males with HCA-FUTI and so was the prevalence of extended-spectrum beta-lactamase and AmpC E. coli and Klebsiella spp.-producing strains (p = 0.012). Inadequate antimicrobial treatment and all-cause in-hospital mortality was associated with HCA-FUTI (p < 0.001 and p = 0.004, respectively). Independent factors for mortality were severe sepsis or septic shock [odds ratio (OR) 29; 95% confidence interval (CI): 3.9-214] and cirrhosis (OR 23.7; 95% CI: 1.6-350.6). Male patients with HCA-FUTI have different clinical characteristics, outcomes and microbiological features compared to CA-FUTI patients. Previous contact with the healthcare system has to be taken into consideration when deciding the optimal antimicrobial treatment in males with FUTI.

Multidrug resistant and carbapenemase producing Enterobacteriaceae among patients with urinary tract infection at referral Hospital, Northwest Ethiopia

BACKGROUND

Updates on the epidemiology of antibiotic resistance bacterial pathogens is important. This is because the spread of multidrug resistant enterobacteriaceae (MDRE) and recently carbapenemase producing enterobacteriaceae (CPE) have emerged as a major public health concern in patients with urinary tract infections (UTIs). This study is therefore, aimed to assess the prevalence and associated risk factors of MDR and CPE among patients with UTIs.

METHODS

A cross sectional study was conducted among 442 symptomatic UTI suspected patients. Data on socio-demographic characteristics, clinical information and possible risk factors were collected using structured questionnaire. Early morning mid-stream urine samples were collected and processed to characterize bacterial isolates. Disk diffusion method was used to determine the antibiotic susceptibility patterns of isolates. Carbapenemase producing strains were detected using CHROMagar KPC medium. Data were entered and analyzed using SPSS version 20. P-value <0.05 was considered as statistical significant.

RESULTS

Among 442 patients enrolled a total of 183 Enterobacteriaceae were recovered. Of these isolates; 160 (87.4%) were MDRE; the most common isolates were K. pneumoniae and E.coli. Five (2.73%) of the isolates were found to be carbapenemase producers and all of CPE strains were 100% ESBL producers. Significant drug resistances were observed among CPE compared to other MDRE, low resistance rates were noted to ciprofloxacin (20%). Being female (OR 4.46; P = 0.018), age (OR 1.08; P = 0.001), hospitalization (OR 5.23; P = 0.006), and prior antibiotic use (OR 3.98; P = 0.04) were associated risk factors for MDRE.

CONCLUSION AND RECOMMENDATION

High rates of MDR (87.4%) were observed among enterobacteriaceae uropathogens; K. pneumoniae and E.coli were the principal MDR isolates. Overall prevalence of CPE was 2.73% and all of these strains were 100% ESBL producer. Attributing risk factors for MDR UTIs were found to be sex (female), age, hospitalization, and history of antibiotic therapy. Therefore, efforts should be made to reduce patient hospital stay and maximize rational use of drugs. Additional and vigorous investigation especially on CPE should be encouraged.

A clinical decision rule identifies risk factors associated with antimicrobial-resistant urinary pathogens in the emergency department: a retrospective validation study

BACKGROUND

Identifying patients at high risk for multidrug-resistant urinary tract infections (UTIs) is important for guiding empirical antimicrobial therapy. Clinical risk factors associated with antimicrobial-resistant urinary pathogens and the derivation of a simple clinical decision rule could help define health care-associated UTI.

OBJECTIVE

To derive a simple clinical decision rule to identify clinical risk factors associated with antimicrobial-resistant urinary pathogens.

METHODS

This was a retrospective case-control study of all emergency department (ED) patients from July 1, 2011, to July 1, 2012, who presented to the ED with UTI and a positive urine culture. Candidate risk factors were collected retrospectively from medical record review. We compared differences in patient characteristics stratified by the presence of an antimicrobial-resistant urinary pathogen.

RESULTS

A total of 360 patients with UTI had a positive, noncontaminated urine culture during the study period. About 6.7% of patients (n = 24) had a multidrug-resistant (MDR) urinary infection. Logistic regression modeling identified 3 clinical factors associated with the identification of a MDR pathogen: male sex, chronic hemodialysis, and nursing home residence. A scoring system was created to identify patients with MDR pathogens. Test characteristics were calculated using bootstrapping for internal validation, with a sensitivity of 74.7% (95% CI = 55.1%-91.3%) and specificity of 85.1% (95% CI = 77.8%-86.2%), positive likelihood ratio of 4.3, and a negative likelihood ratio of 0.3.

CONCLUSIONS

Clinical factors can be used to identify UTI patients at high risk of MDR urinary pathogens.