High rates of quinolone resistance among urinary tract infections in the ED

The effect of novel β-lactam derivatives synthesized from substituted phenethylamines on resistance genes of MRSA isolates

This study focuses on the activity of previously reported imine and β-lactam derivatives against methicillin-resistant Staphylococcus aureus (MRSA) isolates. The presence of mecA and blaZ genes in the isolates was determined, and the minimum inhibitory concentration (MIC) values were determined based on the antibacterial activity against these isolates. Active compounds were selected and their ability to act against resistant isolates in vitro was determined. Concurrently, biochemical (nitrocefin) and molecular (qRT-PCR) tests were used to investigate the ability of the compounds to induce resistance genes in MRSA isolates. The cytotoxicity of the compounds on human dermal fibroblasts (HDF) was investigated. The MIC values of compounds (10) and (12) against MSSA and MRSA isolates were 7.81 and 15.62 μg ml-1, respectively. The most active compounds were identified as (10) and (12), and it was observed that the isolates did not develop resistance to these compounds in vitro. These compounds were found to inhibit β-lactamase, reduce the expression of resistance genes, and exhibit reduced HDF cell toxicity in a dose-dependent manner. According to the findings of the study, it can be concluded that these compounds show promise as hits with an interesting mechanism of action for further chemical modifications to develop new MRSA inhibitors.

Trends and predictors of antimicrobial resistance among patients with urinary tract infections at a tertiary hospital facility in Alexandria, Egypt: a retrospective record-based classification and regression tree analysis

BACKGROUND

The incidence of Antimicrobial Resistance (AMR) in uropathogens varies between countries and over time. We aim to study the patterns and potential predictors of AMR among patients with UTIs admitted to the Urology Department at Alexandria University Hospital.

METHODS

An observational retrospective record-based study was conducted on all patients admitted to the Urology department from October 2018 to October 2020. Data collected from patients' records included: demographic data, diagnosis on admission, history of chronic diseases, duration of hospital stay, insertion of a urinary catheter, duration of the catheter in days, history of the use of antibiotics in the previous three months, and history of urinary tract operations. If UTI was documented, we abstracted data about urine culture, use of antibiotics, results of urine cultures, type of organism isolated, and sensitivity to antibiotics. We conducted a multivariable logistic regression model. We performed Classification and Regression Tree Analysis (CART) for predicting risk factors associated with drug resistance among patients with UTI. Data were analyzed using SPSS statistical package, Version 28.0, and R software (2022).

RESULTS

This study encompassed 469 patients with UTIs. The most commonly isolated bacterium was Escherichia coli, followed by Klebsiella pneumoniae. Multidrug resistance (MDR) was found in 67.7% (149/220) of patients with hospital-acquired UTIs and in 49.4% (83/168) of patients with community-acquired UTIs. Risk factors independently associated with antimicrobial resistance according to logistic regression analysis were the use of antibiotics within three months (AOR = 5.2, 95% CI 2.19-12.31), hospital-acquired UTI (AOR = 5.7, 95% CI 3.06-10.76), diabetes mellitus (AOR = 3.8, 95% CI 1.24-11.84), age over 60 years (AOR = 2.9, 95% CI 1.27-6.72), and recurrent UTI (AOR = 2.6, 95% CI 1.08-6.20). Classification and regression tree (CART) analysis revealed that antibiotic use in the previous three months was the most significant predictor for developing drug resistance.

CONCLUSION

The study concluded a high level of antimicrobial resistance as well as significant MDR predictors among hospitalized patients with UTIs. It is vital to assess resistance patterns in our hospitals frequently to improve rational antibiotic treatment as well as to sustain antimicrobial stewardship programs and a rational strategy in the use of antibiotics. Empirical therapy for UTI treatment should be tailored to the potential pathogens' susceptibility to ensure optimal treatment. Strategic antibiotic use is essential to prevent further AMR increases. Further research should focus on suggesting new biological systems or designed drugs to combat the resistance of UTI pathogens.

Comparison of antimicrobial resistance in patients with obstructive pyelonephritis associated with ureteral stones and uncomplicated pyelonephritis

This study aimed to investigate the clinical outcomes of causative microorganisms in obstructive pyelonephritis associated with ureteral stones (OPU) and their antibiotic susceptibilities. This retrospective cohort study included female patients diagnosed with community-acquired acute pyelonephritis (APN) at a tertiary-care hospital between 2008 and 2017. A comparison of APN cases associated with the obstruction of the upper urinary tract by ureteral stones and APN cases without complications was performed. Propensity score (PS) matching was used to adjust the heterogeneity within each group. Of the 588 female patients with community-acquired APN, 107 were diagnosed with OPU and 481 with uncomplicated APN. After PS matching, Enterobacteriaceae strains isolated from OPU cases were more resistant to fluoroquinolones (51.9% vs 16.0%, P < .001). Extended-spectrum β-lactamase was detected in 22.2% and 21.0% of the Enterobacteriaceae strains isolated from OPU and uncomplicated APN cases, respectively (P = 1.000). The treatment failure rate was similar in OPU and uncomplicated APN groups (16.0% vs 21.0%, P = .545). Patients with OPU may be empirically treated with antibiotics in accordance with the treatment protocol for general pyelonephritis. Clinicians should exercise caution in prescribing fluoroquinolones for treating OPU.

Risk Factors for Antibiotic Resistant Urinary Pathogens in Patients Discharged From the Emergency Department

Purpose: Urinary tract infections (UTIs) are one of the most common indications for antimicrobial use in the emergency department (ED). Appropriate empiric selection is crucial to ensure optimal care while limiting broad-spectrum antibiotic use. The primary objective of this study was to evaluate the relationship between patient-specific risk factors and drug resistant urinary pathogens in patients discharged from the ED and followed by Emergency Medicine Pharmacists (EMPs). Methods: This was a single-center, retrospective chart review of adult (≥18 years old) patients with positive urine cultures discharged from the ED. The association between risk factors and pathogen resistance to ≥1 classes of antibiotics was evaluated using multivariate logistic regression. Risk factors included the following: hospitalization within the previous 30 days, intravenous antibiotic use within 90 days, diabetes, clinical atherosclerotic cardiovascular disease, psychiatric disorder, dementia, current antibiotic use for any indication, previous lifetime history of UTIs, indwelling or intermittent catheterization, hemodialysis, previous lifetime history of a urologic procedure, urinary tract abnormality, immunosuppressive disease or medications, current residence in a nursing or rehabilitation facility, and history of a multidrug resistant organism (MDRO). Results: A total of 1018 patients were included. There was an increase in the odds of antibiotic resistance in patients with cystitis and ≥2 risk factors (Odds Ratio [OR] = 1.70, 95% CI = 1.24-2.32). In those with pyelonephritis, there was a non-significant increase in the odds of resistance for those with ≥2 risk factors (OR = 1.83, 95% CI = 0.98-3.42). Patients with pyelonephritis discharged on inappropriate antibiotics were more likely to return to the ED within 30 days (P = .03). Conclusions: For patients with cystitis discharged from the ED, those with ≥2 patient-specific risk factors had significantly increased odds of antibiotic resistance. Patients with pyelonephritis, but not cystitis, who were discharged on inappropriate antibiotics were more likely to return to the ED within 30 days. In conjunction with an EMP culture follow-up program, the identification of risk factors for antimicrobial resistance can be used to design more patient-specific empiric antibiotic selections.

Bacterial uropathogens and susceptibility testing among patients diagnosed with urinary tract infections at Hiwot Fana Specialized University Hospital, Eastern Ethiopia

Background:

Urinary tract infection is a common infection posing a significant healthcare burden globally. Currently, it is becoming hard to manage due to the drug resistance of uropathogens. This study aimed to evaluate the rate of culture positivity and the susceptibility pattern of isolates among clinically diagnosed patients with urinary tract infection.

Methods:

An institution-based cross-sectional study was conducted on patients clinically diagnosed with urinary tract infections and received a drug prescription at Hiwot Fana Specialized University Hospital from August 2018 to June 2019. A clean-catch mid-stream urine specimen was collected and bacterial identification and susceptibility test were performed using standard microbiological methods. Data were entered into EpiInfo 7 and exported to STATA 15 for analysis. Data were analyzed using descriptive analysis and bi-variate and multivariate regression analyses and presented with graphs, frequency, and tables.

Results:

A total of 687 urine samples were collected from patients with clinically diagnosed urinary tract infections. The mean age was 31 years and 56.62% were female. 28.38% of the participants had a culture-positive result, of which 86.15% had monomicrobial infections. Inpatients (AOR = 3.8, 95% CI = (1.8–7.9)) and hypertensive patients (AOR = 2.1, 95% CI = (1.1–4.4)) had higher odds of culture-positive results. Staphylococcus species (35.3%), E. coli (25.34%), Pseudomonas species (6.8%), and other Enterobacterales are isolated. Most isolates showed resistance to more than one drug, and amikacin, gentamicin, and nitrofurantoin showed relatively higher activity against isolates.

Conclusion:

About one-third of the clinically diagnosed patients with urinary tract infection were culture-positive with many types of bacterial uropathogens. Inpatients and hypertensive patients had a higher risk of developing bacterial infections. Bacterial isolates showed different percentages of susceptibility to the tested antibiotics.

Age and gender-specific antibiotic resistance patterns among Bangladeshi patients with urinary tract infection caused by Escherichia coli

Background

In Bangladesh, treatment for urinary tract infection has become increasingly difficult due to antibiotic resistance. In addition, the prescription of age and gender-specific drugs is still far from being practiced in Bangladesh. We are examining trends of antibiotic resistance per age and gender in patients with urinary tract infection (UTI) caused by the most frequent agent, Escherichia coli.

Methods

We determined the resistance of 1663 E. coli isolates obtained from urine cultures. A sensitivity study using the Kirby-Bauer method was carried out to identify the antibiotic resistance trends.

Results

Imipenem with 1.9% resistance of all isolates found to be the lowest percentage of resistance. Meropenem (2.8%), amikacin (2.8%), colistin (2.9%), and nitrofurantoin (15.8%) showed low resistance percentages. The sensitivity analysis suggests that age and gender (area under curve = 0.67) should be taken into consideration to prescribe amikacin. The increasing odds ratios (OR) by age groups suggest that amikacin is a less effective agent for older patients with UTIs. Moreover, nitrofurantoin (OR = 1.45, 95% confidence interval (CI) = 1.07–1.95) and colistin (OR = 2.09, CI = 1.13–3.76) were less effective against isolates obtained from males compared to isolates obtained from females. Meropenem was effective against bacteria obtained from all age groups and genders. On the other hand, efficacy of imipenem was lower in isolates obtained from adults older than 40 years (OR: 0.44 for < = 18 years, OR = 0.47 for 19–40 years, OR = 0.86 for 41–60 years; reference: > = 61 years).

Conclusion

In Bangladesh, meropenem, imipenem, amikacin, colistin, and nitrofurantoin are suitable therapeutic alternatives against urinary tract pathogens. Among the oral agents, amikacin, colistin, and nitrofurantoin should be prescribed, taking consideration of age and gender. These results will assist physicians in prescribing effective primary care antibiotics for UTI patients and encouraging the implementation of health policies for a safe prescription of antibiotics.

Plasmid-mediated antibiotic resistance among uropathogens in primigravid women-Hyderabad, India

With the growing threat of antimicrobial resistance worldwide, uncovering the molecular epidemiology is critical for understanding what is driving this crisis. We aimed to evaluate the prevalence of plasmid-mediated-quinolone-resistance (PMQR) and extended-spectrum beta-lactamase- (ESBL) producing gram-negative organisms among primigravid women with bacteriuria. We collected urine specimens from primigravid women attending their first antenatal visit at Gandhi Hospital during October 1, 2015 to September 30, 2016. We determined antimicrobial susceptibility and ESBL and quinolone resistance using VITEK-2. We performed polymerase chain reaction amplification on resistant isolates for detection of ESBL-encoding genes (TEM, SHV, CTX-M) and PMQR genes (qnrA, qnrB, qnrD, qnrS, aac (6’)-Ib-cr). Of 1,841 urine samples, 133 demonstrated significant bacterial growth with gram-negative bacilli accounting for 85% of isolates, including Escherichia coli (n = 79), Klebsiella pneumoniae (n = 29), Sphingomonas (n = 3), Enterobacter (n = 1), and Citrobacter (n = 1). We found 65% of E. coli isolates and 41% of K. pneumoniae isolates were ESBL positive. Of ESBL-positive isolates, the most common genes conferring resistance were TEM-1 (66.7%) followed by CTX-M-15 (33.3%). Fifty-seven percent of ESBL-positive E. coli also demonstrated resistance to quinolones with the most common PMQR genes being qnr-S (62.5%) and aac (6')-Ib-cr (37.5%). We did not find any resistance to quinolones among ESBL-positive K. pneumoniae isolates. Across different classes of antibiotics we found a strong clustering of multi-drug resistance in E. coli with over 45% of ESBL-positive isolates demonstrating resistance to at least three classes of antibiotics. This study emphasizes the high prevalence of plasmid-mediated ESBL and quinolone resistance in community-acquired urinary tract infections of primigravid women. The overall abundance of multi-drug-resistant isolates in this population is alarming and may present therapeutic challenges.

Joint Modeling of Resistance to Six Antimicrobials in Urinary Escherichia coli Isolates in Quebec, Canada

Empirical treatment of urinary tract infections should be based on susceptibility profiles specific to the locale and patient population. Additionally, these susceptibility profiles should account for correlations between resistance to different types of antimicrobials.

Empirical treatment of urinary tract infections should be based on susceptibility profiles specific to the locale and patient population. Additionally, these susceptibility profiles should account for correlations between resistance to different types of antimicrobials. We used hierarchical logistic regression models to investigate geographic, temporal, and demographic trends in resistance to six antimicrobials in community-acquired and nosocomial urinary E. coli isolates from three communities in the province of Quebec, Canada, procured between April 2010 and December 2017. A total of 74,986 community-acquired (patient age, ≥18 years) and 4,384 nosocomial isolates (patient age, ≥65 years) were analyzed. In both community-acquired and nosocomial isolates, we found geographic variation in the prevalence of resistance. Male sex (community-acquired hierarchical mean odds ratio [OR], 1.24; 95% credible interval [CI], 1.02 to 1.50; nosocomial hierarchical mean OR, 1.16, 95% CI, 0.92 to 1.41) and recent hospitalization (community-acquired hierarchical mean OR, 1.49; 95% CI, 1.33 to 1.66; nosocomial hierarchical mean OR, 1.31; 95% CI, 0.99 to 1.78) were associated with a higher risk of resistance to most types of antimicrobials. We found distinct seasonal trends in both community-acquired and nosocomial isolates, but only community-acquired isolates showed a consistent annual pattern. Ciprofloxacin resistance increased sharply with patient age. We found clinically relevant differences in antimicrobial resistance in urinary E. coli isolates between locales and patient populations in the province of Quebec. These results could help inform empirical treatment decisions for urinary tract infections. In the future, similar models integrating local, provincial, and national resistance data could be incorporated into decision support systems for clinicians.

The rates of quinolone, trimethoprim/sulfamethoxazole and aminoglycoside resistance among Enterobacteriaceae isolated from urinary tract infections in Azerbaijan, Iran

Aim: Antibiotic susceptibility patterns help to select appropriate empirical treatments of urinary tract infections (UTIs). This study aimed to investigate antibiotic resistance among Enterobacteriaceae isolated from UTIs in Azerbaijan, Iran. Methods: This study was carried out during 2016 in hospitals located in Tabriz, Urmia, and Khoy. Midstream urine specimens were cultured and identified by the standard methods. Susceptibility testing was carried out using the disk diffusion agar method for cefotaxime, ceftazidime, ceftriaxone, cefoxitin, imipenem, meropenem, ertapenem, cefepime, ampicillin, cefazolin, cefuroxime, aztreonam, nitrofurantoin, and fosfomycin and the agar dilution method for MIC determination of aminoglycosides, quinolones, sulfamethoxazole, and trimethoprim. Results: A total of 219 non-duplicated Enterobacteriaceae were isolated from UTIs. According to the agar dilution assay, the following resistance rates were determined: trimethoprim/sulfamethoxazole (co-trimoxazole) 69.8%, nalidixic acid 68.9%, ciprofloxacin 66.2%, levofloxacin 58.5%, tobramycin 47.9%, kanamycin 39.3%, gentamicin 27.8%, and amikacin 5.5%. High levels of resistance were observed to trimethoprim (78.5%), sulfamethoxazole (88.1%), ampicillin (86.3%), and cephazoline (79.4%). Conclusion: The most effective agents against Enterobacteriaceae were fosfomycin, carbapenems, and amikacin. Quinolones, trimethoprim and sulfamethoxazole are not appropriate for empirical therapy due to high levels of resistance. Amikacin is more effective among aminoglycosides and may be more effective, in complicated cases, when used in combination with fosfomycin and carbapenems.

Urinary Tract Infection Antibiotic Resistance in the United States

Urinary tract infection (UTI) is one of the most common entities in medicine and affected patients present daily in a typical family medicine practice. The patients often present with the "classic symptoms" of dysuria and increased frequency, but sometimes they are asymptomatic or have a mixed picture. In most cases, an antibiotic is prescribed, and this practice is likely contributing to increasing worldwide antibiotic resistance. To help combat this problem, it is important that clinicians seek out their local bacterial resistance patterns and antibiograms, properly diagnose and treat UTI if indicated, and recognize their role in antibiotic stewardship.

Leveraging Antimicrobial Stewardship in the Emergency Department to Improve the Quality of Urinary Tract Infection Management and Outcomes

BACKGROUND

The complex and fast-paced emergency department (ED) practice setting presents unique challenges that demand a tailored approach to antimicrobial stewardship. In this article, we describe the strategies applied by 1 institution's antimicrobial stewardship program (ASP) that were successful in improving prescribing practices and outcomes for urinary tract infection (UTI) in the ED.

METHODS

Core strategies included pre-implementation research characterizing the patient population, antimicrobial resistance patterns, prescribing behavior, and morbidity related to infection; collaboration across multiple disciplines; development and implementation of a UTI treatment algorithm; education to increase awareness of the algorithm and the background and rationale supporting it; audit and feedback; and early evaluation of post-implementation outcomes.

RESULTS

We observed a rapid change in prescribing post-implementation with increased empiric nitrofurantoin use and reduced cephalosporin use (P < .05). Our elevation of nitrofurantoin to firstline status was supported by our post-implementation analysis showing that its use was independently associated with reduced 30-day return visits (adjusted odds ratio, 0.547; 95% confidence interval, 0.312-0.960). Furthermore, despite a shift to a higher risk population and a corresponding decrease in antimicrobial susceptibility rates post-implementation, the preferential use of nitrofurantoin did not result in higher bug-drug mismatches while 30-day return visits to the ED remained stable.

CONCLUSIONS

We demonstrate that an outcomes-based ASP can impart meaningful change to knowledge and attitudes affecting prescribing practices in the ED. The success of our program may be used by other institutions as support for ASP expansion to the ED.

Empiric antibiotic therapy in urinary tract infection in patients with risk factors for antibiotic resistance in a German emergency department

Background

The aim of this study was to identify clinical risk factors for antimicrobial resistances and multidrug resistance (MDR) in urinary tract infections (UTI) in an emergency department in order to improve empirical therapy.

Methods

UTI cases from an emergency department (ED) during January 2013 and June 2015 were analyzed. Differences between patients with and without resistances towards Ciprofloxacin, Piperacillin with Tazobactam (Pip/taz), Gentamicin, Cefuroxime, Cefpodoxime and Ceftazidime were analyzed with Fisher’s exact tests. Results were used to identify risk factors with logistic regression modelling. Susceptibility rates were analyzed in relation to risk factors.

Results

One hundred thirty-seven of four hundred sixty-nine patients who met the criteria of UTI had a positive urine culture. An MDR pathogen was found in 36.5% of these. Overall susceptibility was less than 85% for standard antimicrobial agents. Logistic regression identified residence in nursing homes, male gender, hospitalization within the last 30 days, renal transplantation, antibiotic treatment within the last 30 days, indwelling urinary catheter and recurrent UTI as risk factors for MDR or any of these resistances. For patients with no risk factors Ciprofloxacin had 90%, Pip/taz 88%, Gentamicin 95%, Cefuroxime 98%, Cefpodoxime 98% and Ceftazidime 100% susceptibility. For patients with 1 risk factor Ciprofloxacin had 80%, Pip/taz 80%, Gentamicin 88%, Cefuroxime 78%, Cefpodoxime 78% and Ceftazidime 83% susceptibility. For 2 or more risk factors Ciprofloxacin drops its susceptibility to 52%, Cefuroxime to 54% and Cefpodoxime to 61%. Pip/taz, Gentamicin and Ceftazidime remain at 75% and 77%, respectively.

Conclusions

We identified several risk factors for resistances and MDR in UTI. Susceptibility towards antimicrobials depends on these risk factors. With no risk factor cephalosporins seem to be the best choice for empiric therapy, but in patients with risk factors the beta-lactam penicillin Piperacillin with Tazobactam is an equal or better choice compared to fluoroquinolones, cephalosporins or gentamicin. This study highlights the importance of monitoring local resistance rates and its risk factors in order to improve empiric therapy in a local environment.

Impact of Clinical and Laboratory Standards Institute breakpoint changes on susceptibility rates of cephalosporins in uncomplicated urinary tract infections caused by Enterobacteriaceae

Breakpoint changes may impact cephalosporin susceptibility rates in uncomplicated urinary tract infections (uUTIs). Applying the ≤16-mg/L breakpoint to urine cultures from adult women in an academic health system resulted in cefazolin being the most active uUTI antimicrobial, with 86.9% susceptibility, compared to levofloxacin (80%), nitrofurantoin (76.5%), and sulfamethoxazole-trimethoprim (72.6%).

Impact of Allergy and Resistance on Antibiotic Selection for Recurrent Urinary Tract Infections in Older Women

OBJECTIVES

To review the impact of antibiotic allergy and resistance in older women with recurrent urinary tract infections (RUTIs) as determinants for a suitable oral antibiotic treatment choice.

METHODS

A prospectively maintained database of women 65 years old and older with documented RUTIs (≥3 UTI/y) and trigonitis on cystoscopy was reviewed. Demographic data, known drug allergies, renal function, antibiotic susceptibility of most recent urine culture, allergy, or resistance to trimethoprim-sulfamethoxazole (TMP-SMX), fluoroquinolones, and nitrofurantoin were obtained.

RESULTS

From 2006 to 2014, 86 women with RUTIs met study criteria. Mean age was 77.9 ± 7.8, with 94% being Caucasian. An estimated glomerular filtration rate >30 mL/min was noted in 94%. The percentage of women allergic, resistant, or both allergic and resistant to TMP-SMX was 33%, 29%, and 15%, to fluoroquinolones was 14%, 34%, and 8.1%, or nitrofurantoin was 16%, 14%, and 5%, respectively. Twenty-eight percent (24 of 86) of women who were allergic and/or resistant to TMP-SMX and fluoroquinolones were sensitive to nitrofurantoin. Twenty percent (17 of 86) were allergic and/or resistant to all 3 antibiotics. Women who were allergic or resistant to TMP-SMX had a significantly higher number of other antibiotic resistances compared with women sensitive to TMP-SMX (4.9 ± 3.6 vs 2.1 ± 2.3; P < .0001). Similarly, women with fluoroquinolone allergy or resistance had significantly more antibiotic resistances than those who were fluoroquinolone sensitive (5.8 ± 3.5 vs 2.3 ± 2.5; P < .0001).

CONCLUSION

Because of allergy and/or antibiotic resistance, several first-line antibiotics are not available for many older women with RUTIs. In nearly a third of women, nitrofurantoin was the only viable alternative.

A Seven-Day Course of TMP-SMX May Be as Effective as a Seven-Day Course of Ciprofloxacin for the Treatment of Pyelonephritis

BACKGROUND

The Infectious Diseases Society of America guidelines recommend either 14 days of trimethoprim-sulfamethoxazole (TMP-SMX) or 7 days of ciprofloxacin for the treatment of pyelonephritis. Antibiotic courses of 7 days of TMP-SMX vs 7 days of ciprofloxacin for pyelonephritis have not been previously compared. We evaluated the odds of a subsequent, symptomatic urinary tract infection (UTI) for women with Escherichia coli pyelonephritis receiving a 7-day course of TMP-SMX vs a 7-day course of ciprofloxacin.

METHODS

Women ages 16 years and older with E. coli pyelonephritis presenting to 5 health care facilities in the greater Maryland area between 2010 and 2016 receiving either TMP-SMX or ciprofloxacin were included. Patients were excluded if they met any of the following criteria: (a) pregnancy, (b) dialysis dependency, (c) E. coli not susceptible to the treatment prescribed, (d) polymicrobial urine culture, or (e) >48 hours of antibiotic therapy other than TMP-SMX or ciprofloxacin.

RESULTS

Of 272 women meeting eligibility criteria, 81 (30%) and 191 (70%) received 7 days of TMP-SMX and 7 days of ciprofloxacin, respectively. In an adjusted model, the likelihood of a recurrent UTI within 30 days for the TMP-SMX and ciprofloxacin groups was similar (adjusted odds ratio 2.30; 95% confidence interval, 0.72-7.42).

CONCLUSIONS

Our findings suggest that 7 days of TMP-SMX therapy may result in similar clinical outcomes compared with 7 days of ciprofloxacin for the treatment of pyelonephritis. Considering the frequency of pyelonephritis and risks of antibiotic resistance and associated toxicities, decreasing the duration of antibiotic therapy for pyelonephritis may impact a large number of women.

Comparison of UTI antibiograms stratified by ED patient disposition

OBJECTIVE

Institutional antibiograms guide Emergency Department (ED) clinicians' empiric antibiotic selection. For this study, we created and compared antibiograms of ED patients stratified by disposition (admitted or discharged).

METHODS

We conducted a cross-sectional study at two hospitals for 2014, comparing antibiograms limited to Escherichia coli urinary tract infections. Study-Specific Antibiograms, created for the study, excluded polymicrobial samples and multiple cultures from the same patient. Study-Specific Antibiograms were arranged by patient disposition: admitted (IP-Only) vs discharged from the ED (ED-Only). Antibiogram data were presented as average antibiotic sensitivities with 95% confidence intervals and demographic data as medians with interquartile ranges. Sensitivities between Study-Specific Antibiograms were compared by Fisher's Exact Test, alpha=0.05, 2 tails.

RESULTS

For Hospital A, 13 antibiotics were compared between Study-Specific ED-Only (n=313) vs IP-Only (n=244). We found that sensitivities to all four antibiotics appropriate for empiric outpatient therapy by Infectious Disease Society of America guidelines were significantly (p<0.0001) higher in the ED-Only compared to IP-Only groups: ciprofloxacin 80% (76-90%) vs 60% (53-69%), levofloxacin 81% (77-91%) vs 63% (57-72%), nitrofurantoin 75% (70-84%) vs 51% (44-58%), and trimethoprim/sulfamethoxazole 73% (68-82%) vs 58% (52-67%). For Hospital B, 14 antibiotics were compared between Study-Specific ED-Only (n=256) and IP-Only (n=168). Two out of the five appropriate empiric outpatient antibiotics had significantly (p<0.0001) higher sensitivities for ED-Only compared to IP-Only: ciprofloxacin 87% (83-91%) vs 71% (64-78%) and levofloxacin 86% (82-91%) vs 71% (65-78%).

CONCLUSIONS

We found higher antibiotic sensitivities in ED-Only than the IP-Only Study-Specific Antibiograms. Our Study-Specific Antibiograms offer an alternative guide for antibiotic selection in the ED.

Comparison of antibiotic susceptibility of Escherichia coli in urinary isolates from an emergency department with other institutional susceptibility data

PURPOSE

The antibiotic susceptibility of Escherichia coli in isolates from patients with uncomplicated urinary tract infection (UTI) in an emergency department (ED) was compared with susceptibility data from the associated hospital.

METHODS

Patients eligible for study participation included women age 18-65 years with one or more symptoms consistent with a UTI for whom a urine dipstick, urinalysis, or urine culture was ordered. Clinical decision-making, including the decision to order a urine culture, was at the discretion of the individual healthcare provider; however, a deidentified urine culture and antimicrobial susceptibility testing were performed for those study participants for whom a urine culture was not ordered. We compared the E. coli-specific antibiogram for uncomplicated UTI to the antibiogram based on all urine cultures in the ED regardless of patient disposition, non-intensive care unit (ICU) hospital inpatients, and the hospitalwide antibiogram.

RESULTS

Of the 578 ED patients screened for study eligibility, 119 met the inclusion criteria. E. coli, detected in 53 (74%) of the 72 pathogen-positive cultures, was the most common pathogen isolated. For E. coli, ciprofloxacin nonsusceptibility was significantly less common in isolates from ED patients with uncomplicated cystitis and pyelonephritis than in isolates from non-ICU inpatients or from the hospitalwide population. E. coli nonsusceptibility to ciprofloxacin was significantly less common in ED isolates from patients with uncomplicated UTI than in isolates from all ED patients with clinician-ordered urine cultures.

CONCLUSION

Antibiotic susceptibility of E. coli in an ED and its associated hospital depended on factors such as whether patients were hospitalized and whether ED isolates were from patients with uncomplicated UTI.

The Toronto Consensus for the Treatment of Helicobacter pylori Infection in Adults

BACKGROUND & AIMS

Helicobacter pylori infection is increasingly difficult to treat. The purpose of these consensus statements is to provide a review of the literature and specific, updated recommendations for eradication therapy in adults.

METHODS

A systematic literature search identified studies on H pylori treatment. The quality of evidence and strength of recommendations were rated according to the Grading of Recommendation Assessment, Development and Evaluation (GRADE) approach. Statements were developed through an online platform, finalized, and voted on by an international working group of specialists chosen by the Canadian Association of Gastroenterology.

RESULTS

Because of increasing failure of therapy, the consensus group strongly recommends that all H pylori eradication regimens now be given for 14 days. Recommended first-line strategies include concomitant nonbismuth quadruple therapy (proton pump inhibitor [PPI] + amoxicillin + metronidazole + clarithromycin [PAMC]) and traditional bismuth quadruple therapy (PPI + bismuth + metronidazole + tetracycline [PBMT]). PPI triple therapy (PPI + clarithromycin + either amoxicillin or metronidazole) is restricted to areas with known low clarithromycin resistance or high eradication success with these regimens. Recommended rescue therapies include PBMT and levofloxacin-containing therapy (PPI + amoxicillin + levofloxacin). Rifabutin regimens should be restricted to patients who have failed to respond to at least 3 prior options.

CONCLUSIONS

Optimal treatment of H pylori infection requires careful attention to local antibiotic resistance and eradication patterns. The quadruple therapies PAMC or PBMT should play a more prominent role in eradication of H pylori infection, and all treatments should be given for 14 days.

ED pharmacist monitoring of provider antibiotic selection aids appropriate treatment for outpatient UTI

OBJECTIVE

We sought to determine whether an emergency department (ED) pharmacist could aid in the monitoring and correction of inappropriate empiric antibiotic selection for urinary tract infections in an outpatient ED population.

METHODS

Urine cultures with greater than 100 000 CFU/mL bacteria from the University of Utah Emergency Department over 1 year (October 2011-Sept 2012) were identified using our electronic medical record system. Per ED protocol, an ED pharmacist reviews all cultures and performs a chart review of patient symptoms, diagnosis, and discharge antibiotics to determine whether the treatment was appropriate. A retrospective review of this process was performed to identify how often inappropriate treatment was recognized and intervened on by an ED pharmacist.

RESULTS

Of the 180 cultures included, a total of 42 (23%) of empiric discharge treatments were considered inappropriate and required intervention. In 35 (83%) of 42 patients, the ED pharmacist was able to contact the patient and make appropriate changes; the remaining 7 patients were unable to be contacted, and no change could be made in their treatment.

CONCLUSION

A chart review of all urine cultures with greater than 100 000 CFU/mL performed by an ED pharmacist helped identify inappropriate treatment in 23% of patients discharged to home with the diagnosis of urinary tract infection. Of these patients who had received inappropriate treatment, an ED pharmacist was able to intervene in 83% of cases. These data highlight the role of ED pharmacists in improving patient care after discharge.

Recommended Initial Antimicrobial Therapy for Emphysematous Pyelonephritis: 51 Cases and 14-Year-Experience of a Tertiary Referral Center

The aim of this study was to investigate the profiles of pathogens and patterns of antibiotic resistance of emphysematous pyelonephritis (EPN), offering recommendations for initial antibiotic treatment.Between January, 2001, and November, 2014, demographic data, presenting clinical features, management strategies, and treatment outcomes of 51 patients with EPN were retrospectively reviewed, analyzing microbiological characteristics of causative pathogens and patterns of antibiotic resistance.Overall survival rate was 90.2% (46/51). Pathogens isolated most frequently were Escherichia coli (49.0%), Klebsiella pneumoniae (19.6%), and Proteus mirabilis (17.7%). Approximately 24% of E coli isolates and 22% K pneumoniae isolates were resistant to fluoroquinolones. Improper empiric antibiotic use (P = 0.02) and third-generation cephalosporin-resistant pathogens (G3CRP) (P = 0.01) were significantly more common in cases of patient fatality. Prior hospitalization and antibiotic use within past year (P = 0.03), need for emergency hemodialysis (P = 0.03), and development of disseminated intravascular coagulation (DIC) (P = 0.03) were factors correlating significantly with microbial resistance to third-generation cephalosporins. The area under the receiver operating characteristic curve was 0.91. The cut-off point determined by the maximum Youden index for 2 of these 3 factors yielded a sensitivity of 0.8 and specificity of 0.93.Third-generation cephalosporins are recommended as initial treatment of EPN. In patients with histories of prior hospitalization and antibiotic use and in those needing emergency hemodialysis or developing DIC, carbapenem is the empiric antibiotic of choice. Patients presenting with 2 or more factors carry the highest risk of G3CRP involvement. Fluoroquinolone and gentamicin should be avoided.

Origin and Dissemination of Antimicrobial Resistance among Uropathogenic Escherichia coli

Antimicrobial agents of various types have important bearing on the outcomes of microbial infections. These agents may be bacteriostatic or –cidal, exert their impact via various means, originate from a living organism or a laboratory, and appropriately be used in or on living tissue or not. Though the primary focus of this chapter is on resistance to the antimicrobial agents used to treat uropathogenic Escherichia coli (UPEC)-caused urinary tract infections (UTIs), some attention will be given to UPEC’s resistance to silver-containing antiseptics, which may be incorporated into catheters to prevent foreign body-associated UTIs.

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.

'Supermutators' found amongst highly levofloxacin-resistant E. coli isolates: a rapid protocol for the detection of mutation sites

Fluoroquinolone resistance is gradually acquired through several mechanisms. In particular, chromosomal mutations in the genes encoding topoisomerases II and IV and increased expression of the multidrug efflux pump AcrAB-TolC are the most common mechanisms. In this study, multiplex polymerase chain reaction (PCR) protocols were designed for high-throughput sequencing of the quinolone resistance determining regions of topoisomerases genes (gyrA, parC and parE) and/or the expression regulation systems of multidrug efflux pump AcrAB (acrRAB, marRAB and soxSR). These protocols were applied to sequence samples from five subpopulations of 103 clinical Escherichia coli isolates. These subpopulations were classified according to their levofloxacin susceptibility pattern as follows: highly resistant (HR), resistant (R), intermediate (I), reduced susceptibility (RS) and susceptible (S). All HR isolates had mutations in the six genes surveyed, with two ‘supermutator' isolates harboring 13 mutations in these six genes. Strong associations were observed between mutations in acrR and HR isolates, parE and R/HR isolates and parC and I/R/HR isolates, whereas surprisingly, gyrA mutations were common in RS/I/R/HR isolates. Further investigation revealed that strong associations were limited to the triple mutations gyrA-S83L/D87N/R237H and HR isolates and the double mutations S83L/D87N and I/R/HR isolates, whereas the single mutation S83L was common in RS/I/R/HR isolates. Interestingly, two novel mutations (gyrA-R237H and acrR-V29G) were located and found to strongly associate with HR isolates. To the best of our knowledge, the gyrA-R237H and acrR-V29G mutations have never been reported and require further investigation to determine their exact role in resistance or ‘fitness' as defined by their ability to compensate for the organismal cost of gaining resistance.

Prevalence and antibiotic resistance pattern of urinary tract bacterial infections in Dessie area, North-East Ethiopia

BACKGROUND

Different studies have indicated that urinary tract infections frequently occur in both community and hospital environments and are of the most common bacterial infections in humans. the outcomes of urinary tract infections are increased hospitalization, increased direct patient costs and mortality. In Dessie, the prevalence of the commmon pathogens and antibiotic susceptibility pattern is not well studied sofar. Thus, the aim of this study is to address these gaps in the study area.

METHODS

Retrospective study was conducted in Dessie regional health reseacrh laboratory from January 1-March 31, 2012. All culture and antibiotic susceptibility test results of patients' diagnosed with UTI from September 2002 to September 2011 G.C were included in the study. Data were abstracted using structured questionnaires and finally, entered into SPSS Windows version 16.0, and descriptive statistics was generated to meet the study objective.

RESULTS

During the last ten years 680 (27.35%) bacteria were isolated in the regional laboratory. The most commonly isolated were E. coli 410 (60.29%), Pseudomonas species 59 (8.68%), Proteus species 53 (7.79%), S. aurous 50 (7.35%) and Klebsiella species 40 (5.88%). The E.coli were susceptible to Nitrofurantoin 43 (89.6%), furantoin 124 (87.3%), Nalidixic acid 91 (86.7%), kanamycin 116 (80%) & ciprofloxacin 66 (71.7%) but were almost resistant to Ampicillin, tetracycline, & trimethoprim-sulfamethoxazole. Similarly Pseudomonas and proteus species were resistant to almost all antibiotics except Gentamycin.

CONCLUSION

The E.coli, pseudomonas and proteus species were the commonly isolated bacteria in the regional health research laboratory. A majority of isolated bacterial microbes were resistant to antibiotics commonly used in clinical practices and generally available in the local economy without prescription. Culture results are necessary before initiating antibiotics.

Factors associated with ciprofloxacin- and cefotaxime-resistant Escherichia coli in women with acute pyelonephritis in the emergency department

BACKGROUND

High rates of antimicrobial resistance in Escherichia coli isolated from patients with urinary tract infections have been reported worldwide. The aim of this study was to identify risk factors for resistance to ciprofloxacin (CIP) and cefotaxime (CTX) in E. coli isolated from patients with acute pyelonephritis (APN).

METHODS

We prospectively identified women over 18 y of age who visited the emergency department of one of 10 hospitals with APN and whose urine culture grew E. coli. The study was conducted from April 16 to June 10, 2012.

RESULTS

Of the 229 patients identified, 173 (75.5%) had community-associated (CA) infections and 56 (24.5%) had healthcare-associated (HCA) infections. Sixty-seven isolates (29.3%) were resistant to CIP, 45 (19.7%) to CTX, and 29 (12.7%) to both CIP and CTX. Multivariate analyses revealed that hematologic disease, chronic kidney disease, a bed-ridden state, indwelling urinary catheter, antibiotic treatment in the preceding 3 months, and isolation of CIP-resistant E. coli in the urine within the preceding 3 months, were significantly associated with resistance to both CIP and CTX.

CONCLUSIONS

Chronic conditions and healthcare-associated factors were related to resistance to both fluoroquinolones and third-generation cephalosporins in women with APN. Continued and vigilant surveillance is necessary to monitor the dissemination of antimicrobial resistance in uropathogens.

Antimicrobial susceptibility patterns among Escherichia coli urinary isolates from community-onset health care-associated urinary tract infection

Urinary tract infection (UTI) is traditionally classified as community-acquired (CA) and hospital-acquired (HA). Community-onset health care-associated (HCA) infection is a new category that has gained increasing attention. The study aimed to compare the disk susceptibility of nonrepetitive Escherichia coli urinary isolates from HCA-UTI (n = 100) with that of E. coli isolates from CA-UTI (n = 85) and HA-UTI (n = 106). We found that the susceptibility pattern of HCA-UTI E. coli isolates was similar to that of HA-UTI E. coli isolates, but significantly different from that of CA-UTI E. coli isolates. In particular, the proportion of extended-spectrum β-lactamase-producing isolates was significantly higher in HCA-UTI than that in CA-UTI (30.0% vs. 3.5%, p < 0.001). We recommend that when treating HCA-UTI, it is necessary to take urine cultures for susceptibility testing to guide definite antibiotic therapy.

Analysis of the spectrum and antibiotic resistance of uropathogens in vitro: results based on a retrospective study from a tertiary hospital

BACKGROUND

Antibiotic resistance of uropathogens in urinary tract infections (UTIs) is increasing worldwide. This study aimed to compare the spectrum and antimicrobial resistance of uropathogens in community-acquired UTIs (CAUTIs) and nosocomial-acquired UTIs (NAUTIs) at a tertiary hospital in China.

METHODS

Retrospective analysis of uropathogens from UTI patients was performed at Zhong Da Hospital.

RESULTS

A total of 1129 strains was isolated from 653 community-acquired and 476 nosocomial-acquired infections. Escherichia coli was the most common uropathogen, accounting for 55.9% of the CAUTIs and 27.1% of the NAUTIs. Among the CAUTIs, Escherichia coli was followed in prevalence by Enterococcus spp (12.9%) and Proteus mirabilis (3.7%). Among the NAUTIs, Escherichia coli was followed by Enterococcus spp (15.3%) and Klebsiella pneumoniae (6.9%). The proportion of fungi in the NAUTIs (23.7%) was higher than that in the CAUTIs (3.1%) (P < .05). Extended-spectrum β-lactamase-producing strains of E coli accounted for 70.6% of the NAUTIs and 47.3% of the CAUTIs. Carbapenems, amikacin, and nitrofurantoin were active agents against E coli. The resistance rates of E coli to cephalosporins, ampicillin, ampicillin/sulbactam, quinolones, and gentamicin were higher in the NAUTIs than in the CAUTIs (P < .05).

CONCLUSION

The distribution of species was different between CAUTIs and NAUTIs. Higher antibiotic resistance rates were observed in the NAUTIs than in the CAUTIs.

Management of urinary tract infections in the era of increasing antimicrobial resistance

Antimicrobial resistance of urinary pathogens is increasing. Most urinary tract infections (UTIs) should still be treated empirically. However, patients with recurrence or other risk factors for resistance may benefit from urine culture. Patients with recurrent UTI often resort to antibiotic prevention, a risky proposition in terms of resistance. Non-antimicrobial preventative methods should be considered first. If preventative antibiotics must be used, postcoital patient-initiated protocols are effective and reduce overall antibiotic exposure compared with continuous prophylaxis. Consider referring patients for urologic evaluation when at risk for complicated UTIs or when recurrence continues despite conservative interventions.

Global fluoroquinolone resistance epidemiology and implictions for clinical use

This paper on the fluoroquinolone resistance epidemiology stratifies the data according to the different prescription patterns by either primary or tertiary caregivers and by indication. Global surveillance studies demonstrate that fluoroquinolone resistance rates increased in the past years in almost all bacterial species except S. pneumoniae and H. influenzae, causing community-acquired respiratory tract infections. However, 10 to 30% of these isolates harbored first-step mutations conferring low level fluoroquinolone resistance. Fluoroquinolone resistance increased in Enterobacteriaceae causing community acquired or healthcare associated urinary tract infections and intraabdominal infections, exceeding 50% in some parts of the world, particularly in Asia. One to two-thirds of Enterobacteriaceae producing extended spectrum β-lactamases were fluoroquinolone resistant too. Furthermore, fluoroquinolones select for methicillin resistance in Staphylococci. Neisseria gonorrhoeae acquired fluoroquinolone resistance rapidly; actual resistance rates are highly variable and can be as high as almost 100%, particularly in Asia, whereas resistance rates in Europe and North America range from <10% in rural areas to >30% in established sexual networks. In general, the continued increase in fluoroquinolone resistance affects patient management and necessitates changes in some guidelines, for example, treatment of urinary tract, intra-abdominal, skin and skin structure infections, and traveller's diarrhea, or even precludes the use in indications like sexually transmitted diseases and enteric fever.

Correlation between levofloxacin consumption and the incidence of nosocomial infections due to fluoroquinolone-resistant Escherichia coli

BACKGROUND/PURPOSE

The relationship between fluoroquinolone resistance in Escherichia coli isolates causing nosocomial infection and hospital antibiotic consumption were investigated. Restriction of levofloxacin use was implemented to control the incidence of fluoroquinolone-resistant E coli in the hospital.

METHODS

The study was conducted from January 2004 to December 2010. Antimicrobial agent consumption was obtained from the pharmacy computer system and presented as the defined daily doses per 1000 patient-days every 6 months. The incidence of fluoroquinolone-resistant E coli isolates causing nosocomial infections was obtained from the Department of Infection Control every 6 months. An antimicrobial stewardship program, restricting levofloxacain use, was implemented in July 2007.

RESULTS

The incidence of fluoroquinolone-resistant E coli causing nosocomial infections was significantly correlated with fluoroquinolone usage (p = 0.005), but not with the use of third- or fourth-generation cephalosporins, piperacillin-tazobactam, or carbapenems. Parenteral (p = 0.002), oral (p = 0.018), and total levofloxacin (p = 0.001) use were significantly correlated with the extent of fluoroquinolone resistance. With a reduction of levofloxacin use, a decrease of the incidence of fluoroquinolone resistance in E coli isolates was observed.

CONCLUSION

There is a significant correlation between levofloxacin use and the incidence of nosocomial fluoroquinolone-resistant E coli isolates. The incidence of fluoroquinolone-resistant E coli could be reduced by limiting levofloxacin consumption.

Influence of antibiotic susceptibility patterns on empiric antibiotic prescribing for children hospitalized with community-acquired pneumonia

OBJECTIVE

The aim of this study was to determine the influence of pneumococcal penicillin-nonsusceptibility patterns on individual antibiotic prescription among 33 children's hospitals using a multilevel, random- intercept, logistic regression analysis.

METHODS

It was a multilevel cross-sectional study. The participants were children, 1-18 years of age, with community-acquired pneumonia (CAP) who were discharged in 2006. Hospital antibiotic susceptibility data were collected from surveys, and patient data were obtained from an administrative database. The primary exposure was the proportion of penicillin-nonsusceptible pneumococcal isolates reported in 2005 by each hospital. A secondary exposure included using the proportion of penicillin-resistant pneumococcal isolates to determine whether a threshold of susceptibility existed. Receipt of broad-spectrum empiric antibiotic therapy in 2006 (ie, antibiotics other than penicillins or aminopenicillins) was the main outcome measure.

RESULTS

Four thousand eight hundred eighty-eight children diagnosed with CAP were eligible. The proportion of penicillin-nonsusceptible isolates ranged from 9% to 70% across hospitals whereas the proportion of penicillin-resistant isolates ranged from 0% to 60%. Broad-spectrum antibiotics were prescribed to 93% of patients; 45% of patients received cephalosporin class antibiotics alone. There was no significant association between the proportion of pencillin-nonsusceptible pneumococcal isolates at individual hospitals and narrow-spectrum prescribing. However, every 10% increase in penicillin-resistant pneumococcal isolates was associated with a 39% increase in broad-spectrum antibiotic prescribing (adjusted odds ratio: 1.39; 95% confidence interval: 1.08-1.69).

CONCLUSIONS

There was substantial variability in empiric antibiotic prescribing for CAP among children's hospitals in the United States. High-levels (ie, resistant) but not modest-levels (ie, intermediate susceptibility) of penicillin resistance were associated with broad-spectrum antibiotic prescribing.

Resistance surveillance studies: a multifaceted problem--the fluoroquinolone example

INTRODUCTION

This review summarizes data on the fluoroquinolone resistance epidemiology published in the previous 5 years.

MATERIALS AND METHODS

The data reviewed are stratified according to the different prescription patterns by either primary- or tertiary-care givers and by indication. Global surveillance studies demonstrate that fluoroquinolone- resistance rates increased in the past several years in almost all bacterial species except Staphylococcus pneumoniae and Haemophilus influenzae causing community-acquired respiratory tract infections (CARTIs), as well as Enterobacteriaceae causing community-acquired urinary tract infections. Geographically and quantitatively varying fluoroquinolone resistance rates were recorded among Gram-positive and Gram-negative pathogens causing healthcare-associated respiratory tract infections. One- to two-thirds of Enterobacteriaceae producing extended-spectrum β-lactamases (ESBLs) were fluoroquinolone resistant too, thus, limiting the fluoroquinolone use in the treatment of community- as well as healthcare-acquired urinary tract and intra-abdominal infections. The remaining ESBL-producing or plasmid-mediated quinolone resistance mechanisms harboring Enterobacteriaceae were low-level quinolone resistant. Furthermore, 10-30 % of H. influenzae and S. pneumoniae causing CARTIs harbored first-step quinolone resistance determining region (QRDR) mutations. These mutants pass susceptibility testing unnoticed and are primed to acquire high-level fluoroquinolone resistance rapidly, thus, putting the patient at risk. The continued increase in fluoroquinolone resistance affects patient management and necessitates changes in some current guidelines for the treatment of intra-abdominal infections or even precludes the use of fluoroquinolones in certain indications like gonorrhea and pelvic inflammatory diseases in those geographic areas in which fluoroquinolone resistance rates and/or ESBL production is high. Fluoroquinolone resistance has been selected among the commensal flora colonizing the gut, nose, oropharynx, and skin, so that horizontal gene transfer between the commensal flora and the offending pathogen as well as inter- and intraspecies recombinations contribute to the emergence and spread of fluoroquinolone resistance among pathogenic streptococci. Although interspecies recombinations are not yet the major cause for the emergence of fluoroquinolone resistance, its existence indicates that a large reservoir of fluoroquinolone resistance exists. Thus, a scenario resembling that of a worldwide spread of β-lactam resistance in pneumococci is conceivable. However, many resistance surveillance studies suffer from inaccuracies like the sampling of a selected patient population, restricted geographical sampling, and undefined requirements of the user, so that the results are biased. The number of national centers is most often limited with one to two participating laboratories, so that such studies are point prevalence but not surveillance studies. Selected samples are analyzed predominantly as either hospitalized patients or patients at risk or those in whom therapy failed are sampled; however, fluoroquinolones are most frequently prescribed by the general practitioner. Selected sampling results in a significant over-estimation of fluoroquinolone resistance in outpatients. Furthermore, the requirements of the users are often not met; the prescribing physician, the microbiologist, the infection control specialist, public health and regulatory authorities, and the pharmaceutical industry have diverse interests, which, however, are not addressed by different designs of a surveillance study. Tools should be developed to provide customer-specific datasets.

CONCLUSION

Consequently, most surveillance studies suffer from well recognized but uncorrected biases or inaccuracies. Nevertheless, they provide important information that allows the identification of trends in pathogen incidence and antimicrobial resistance.

In vitro antimicrobial resistance of urinary Escherichia coli isolates among U.S. outpatients from 2000 to 2010

This study examines in vitro antimicrobial resistance data from Escherichia coli isolates obtained from urine samples of U.S. outpatients between 2000 and 2010 using The Surveillance Network (TSN). Antimicrobial susceptibility results (n = 12,253,679) showed the greatest increases in E. coli resistance from 2000 to 2010 for ciprofloxacin (3% to 17.1%) and trimethoprim-sulfamethoxazole (TMP-SMX) (17.9% to 24.2%), whereas nitrofurantoin (0.8% to 1.6%) and ceftriaxone (0.2% to 2.3%) showed minimal change. From 2000 to 2010, the antimicrobial resistance of urinary E. coli isolates to ciprofloxacin and TMP-SMX among outpatients increased substantially.

The role of fluoroquinolones in the management of urinary tract infections in areas with high rates of fluoroquinolone-resistant uropathogens

Fluoroquinolones have been recommended as the drugs of choice for the empirical treatment of uncomplicated and complicated urinary tract infections (UTIs) caused by trimethoprim-sulfamethoxazole-resistant uropathogens. However, because of the increased use of both oral and parenteral fluoroquinolones for other kinds of infections, increasing rates of resistance to fluoroquinolones among the most common uropathogens have challenged this recommendation, particularly in the Asia-Pacific region. The current interpretative criteria for the in vitro susceptibility of uropathogens to some fluoroquinolones, such as levofloxacin and ciprofloxacin, are set according to their therapeutic efficacy for bloodstream infections, and are not specific to UTIs. Fluoroquinolones exhibit concentration-dependent antibacterial activity, high renal excretion, and relatively early and prolonged urinary bactericidal titers. Whether or not current interpretative criteria for the in vitro susceptibility of uropathogens to fluoroquinolones predict clinical failure in treating UTIs is still controversial. The Clinical and Laboratory Standards Institute (CLSI) has established UTI-specific breakpoints for resistance to a few fluoroquinolones. However, the application of high-dose fluoroquinolone therapy for the treatment of mild to moderate UTIs caused by isolates with higher minimum inhibitory concentrations (MICs) of several fluoroquinolones needs to be re-validated based on more relevant clinical studies, prudent pharmacokinetic/pharmacodynamic (PK/PD) considerations, and thorough study of the mutant prevention concentration of fluoroquinolones in the treatment of UTI.

Prevalence and risk factors for quinolone resistance among Escherichia coli strains isolated from males with community febrile urinary tract infection

The purpose of this study was to evaluate the prevalence and clinical risk factors for quinolone resistance (QR) in E. coli strains from males with febrile urinary tract infection (FUTI). An ambispective cross-sectional study was performed in which we evaluated 153 males with a community FUTI caused by E. coli. Among the 153 FUTI episodes, 101 (66%) were due to quinolone susceptible E. coli strains while 52 (34%) were caused by QR E. coli strains. In the univariate analysis QR was associated with older age, higher Charlson scores, dementia, past UTI, urinary tract abnormalities, previous antibiotic use, particularly with fluoroquinolones (FQ), a healthcare-associated (HA)-UTI (HA-UTI) and to four of the components included in the definition of HA-UTI: hospital admission, nursing home residence, indwelling urethral catheter and invasive urinary instrumentation. In the multivariate analysis, HA-UTI (OR 3.82, 95% CI 1.3-11.24; P 0.015) and use of antimicrobials in the previous month (OR 5.82, 95% CI 2.3-14.88; P < 0.001) mainly with FQ (OR 13.97, 95% CI 2.73-71.53; P 0.002) were associated with QR. To have a HA-UTI and a previous use of FQ in the preceding month were strong risk factors for QR E. coli, and thus empirical antimicrobial treatment with quinolones should be avoided in these patients.

Consensus review of the epidemiology and appropriate antimicrobial therapy of complicated urinary tract infections in Asia-Pacific region

Urinary tract infections (UTIs) are among the most prevalent infectious diseases in the general population. They cause a substantial financial burden in the community and are associated with significant morbidity and mortality, particularly in hospitals. With increased rates of antimicrobial resistance, especially in the Asia-Pacific region, treatment of complicated UTIs (cUTIs) can be challenging for clinicians. Consideration of an optimal antimicrobial agent should be based on local resistance patterns, patient-specific factors, pharmacokinetic and pharmacodynamic principles, and cost. In the Asia-Pacific region, nearly half of Escherichia coli urinary isolates were resistant (including intermediate and resistant) to levofloxacin or ciprofloxacin and ≥30% were resistant to third-generation cephalosporins (cefotaxime, ceftriaxone, and ceftazidime) and cefepime. Overall, 33% of urinary E. coli isolates exhibited extended-spectrum β-lactamase (ESBL)-producing phenotypes. Prevalence of ESBL-producing urinary E. coli was highest in India (60%), followed by Hong Kong (48%) and Singapore (33%). All urinary isolates of E. coli were susceptible to both ertapenem and imipenem. All urinary isolates of Klebsiella pneumoniae were susceptible to imipenem and 4% of them were resistant to ertapenem. Care should be exercised when using trimethoprim-sulfamethoxazole (TMP-SMX), fluoroquinolones, and cephalosporins for the empirical treatment of UTIs, particularly cUTI among moderately to severely ill patients. Empiric antimicrobial treatment for serious cUTIs in which risk factors for resistant organisms exist should include broad-spectrum antibiotics such as carbapenems (ertapenem, imipenem, meropenem, and doripenem) and piperacillin-tazobactam. Aminoglycosides, tigecycline, and polymyxins (colistin or polymyxin B) can be used for the treatment of multidrug-resistant organisms or serious cUTIs when first-line options are deemed inappropriate or patients fail therapy. Because of considerable variability in different countries, local epidemiological data is critical in the effective management of UTIs in the Asia-Pacific region.