Prevalence and risk factors for selection of quinolone-resistant Escherichia coli strains in fecal flora of patients receiving quinolone therapy

The Drug-Specific Propensity Regarding the Acquisition of Fluoroquinolone Resistance in Escherichia coli: An in vitro Challenge and DNA Mutation Analysis

Objective

Many fluoroquinolones, such as ciprofloxacin, are used clinically. We investigated the relationship between resistance acquisition and exposure duration in each drug through the exposure of fluoroquinolone to Escherichia coli clinical isolates in vitro.

Methods

Eleven E. coli clinical isolates were exposed to each fluoroquinolone, ie, ciprofloxacin, levofloxacin, sitafloxacin, garenoxacin, and lascufloxacin, with the concentration of the mutant selection window for 5 days; these procedures were repeated 5-times. In addition, the DNA sequence in the quinolone-resistance determining region (QRDR) and the expression level in the drug efflux pump acrA were analyzed to determine the resistance mechanism.

Results

Although resistant strains were not detected after 5 to 10 days of exposure to fluoroquinolone, after 25 days of exposure to ciprofloxacin and levofloxacin, 100% and 45% of isolates acquired resistance, respectively. Due to 25 days of exposure to sitafloxacin, garenoxacin, and lascufloxacin, MIC measurement was elevated 2- to 4096-fold for those of the parental strain, and the cross-resistance rate to levofloxacin was 72%, 54%, and 27%, respectively. In strains with high fluoroquinolone resistance, acrA overexpression was observed in addition to QRDR mutation.

Conclusion

In our findings, fluoroquinolone resistance was not observed in the E. coli strain after 5- to 10-days of exposure. However, resistance acquisition was detected frequently after 15- to 25-days of exposure. Among fluoroquinolones, lascufloxacn had the least impact on the resistance acquisition in E. coli.

Fluoroquinolone Use Among Hospitalized Children: Diagnosis-Based Stratification to Identify Stewardship Targets

Background

As FQ (fluoroquinolone) use has shifted in pediatric populations, better metrics are needed to guide targeted antibiotic stewardship interventions and limit development of adverse events and resistance, particularly in medically complex children. In this study, we identify high-utilization groups based on underlying medical conditions and describe their relative FQ use over time.

Methods

This study is a retrospective analysis of data from the Pediatric Health Information System database from 2016 to 2020. We identify high-utilization groups based on underlying medical conditions using International Classification of Diseases, Ninth or Tenth Revision codes. We delineate overall trends in the use of FQs in the inpatient setting, including rate and proportional use by each patient group.

Results

Patients with an oncology diagnosis represent a large (25%-44%) and rising proportion (+4.8%/year, P = .001) of national FQ use over the study period. Patients with intra-abdominal infections, including appendicitis, have had a significant increase in both their relative proportional use of FQs (+0.6%/year, P = .037) and proportion of FQ use per admission encounter over the study period (+0.6%/year, P = .008). Patients with cystic fibrosis represent a decreasing proportion of overall use (-2.1%/year, P = .011) and have decreasing FQ use per inpatient encounter (-0.8%/year, P = .001).

Conclusions

Patients with an oncology diagnosis and patients with an intra-abdominal infection appear to be targets for FQ stewardship. Patients with cystic fibrosis have decreasing inpatient FQ use. Key Points: This study describes fluoroquinolone use among hospitalized children from 2016 to 2020, stratified by underlying diagnoses. These trends are used to identify high-yield antibiotic stewardship targets.

Efficacy of Single Dose of Fosfomycin Versus a Five-Day Course of Ciprofloxacin in Patients With Uncomplicated Urinary Tract Infection

Introduction and objective: Treatment has become more challenging due to an aging population, polypharmacy and high prevalence of comorbid illness, antimicrobial antibiotic allergy or sensitivity, an increase in the number of individuals with underlying immunological or structural abnormalities, as well as the frequency of multidrug-resistant infections. Many multidrug-resistant bacteria are still susceptible to nitrofurantoin and fosfomycin, two ancient medicines. Their high urine concentrations and low toxicity give them an advantage over newer medications. This study aimed to compare the efficacy of a single dose of fosfomycin versus a five-day course of ciprofloxacin in patients with uncomplicated urinary tract infections.

Methodology and data collection procedure: This randomized control trial was conducted in the Department of Medicine, Benazir Bhutto Hospital, Rawalpindi. A total of 46 patients were enrolled. Patients were divided randomly into two groups by using the lottery method. In group A, patients were given a single 3 g dose of oral fosfomycin. In group B, patients were given oral ciprofloxacin (500 mg) daily for five days. Then patients were followed-up in the Outpatient Department (OPD) for 28 days. After 28 days, patients were evaluated for resolution of symptoms (as per operational definition). Patients in whom symptoms would not be resolved were managed as per standard protocol. All this information was recorded on proforma.

Results: The average age of the patients in group A was 39.41±9.80 years while in group B that was 41.32±17.76 years. In both groups, 23 females were equally divided. The mean duration of symptoms in group A was 4.78±1.98 days while in group B was 4.95±1.29 days. The minimum duration of symptoms was three days and the maximum was 10 days. In group A, there were 15 (65.21%) patients with efficacy achieved, and among eight (34.78%) patients, efficacy was not achieved while in group B, there were 15 (65.21%) patients in which efficacy was achieved, and among eight (34.78%) patients, efficacy was not achieved. There was no significant association between efficacy and study groups as the p-value was not significant (p=0.87). 

Conclusion: The conclusion of the study was that in the treatment of simple urinary infections, a single dose of fosfomycin had equal efficacy and tolerability as a five-day course of ciprofloxacin.

Risk factors for quinolone-resistant Escherichia coli infection: a systematic review and meta-analysis

Background

Antimicrobial resistance to quinolone is rising worldwide, especially in Escherichia coli causing various infections. Although many studies have been conducted to identify the risk factors for quinolone-resistant Escherichia coli (QREC) infection, the results are inconsistent and have not been systematically reported. The aim of the present study is to conduct a systematic review and meta-analysis to evaluate the potential risk factors for QREC infection.

Methods

A systematic search was performed to collect published data in the EMBASE, PubMed, and the Cochrane Library up to April 2019. Risk factors were analyzed using the pooled odds ratio (ORs) with 95% confidence interval (CIs).

Results

Twenty-seven trials involving 67,019 participants were included in the present study. The following risk factors associated with QREC infection were identified: (1) male (OR = 1.41), (2) hepatic cirrhosis (OR = 2.05), (3) diabetes mellitus (OR = 1.62), (4) cardiovascular disease (OR = 1.76), (5) neurogenic bladder (OR = 8.66), (6) renal dysfunction (OR = 2.47), (7) transplantation (OR = 2.37), (8) urinary tract infection (OR = 2.79) and urinary tract abnormality (OR = 1.85), (9) dementia (OR = 5.83), (10) heart failure (OR = 5.63), (11) neurologic disease (OR = 2.80), (12) immunosuppressive drugs (OR = 2.02), (13) urinary catheter (OR = 4.39), (14) nursing home resident (OR = 4.63), (15) prior surgery (OR = 2.54), (16) quinolones (OR = 7.67), (17) other antibiotics (OR = 2.74), (18) hospitalization (OR = 2.06) and (19) nosocomial infection acquisition (OR = 2.35).

Conclusions

QREC infection was associated with nineteen risk factors including prior quinolones use, hospitalization, and several comorbidities. Reducing exposure to these risk factors and modification of antibiotic use are important to prevent quinolone resistance.

The incidence and risk factors of resistant E. coli infections after prostate biopsy under fluoroquinolone prophylaxis: a single-centre experience with 2215 patients

We evaluated the incidence and risk factors of resistant Escherichia coli infections after the prostate biopsy under flouroquinolone prophylaxis. From January 2003 to December 2012, we retrospectively evaluated the records of 2215 patients. The risk factors were described for infective complications and resistant E. coli in positive cultures was calculated. Of 2215 patients, 153 had positive urine cultures, such as 129 (84·3%) E. coli, 8 (5·2%) Enterococcus spp., 6 (3·9%) Enterobacter spp., 5 (3·2%) Pseudomonas spp., 3 (1·9%) MRCNS, and 2 (1·3%) Klebsiella spp. Of the positive urine cultures which yielded E. coli, 99 (76·7%) were evaluated for fluoroquinolone resistance. Of those, 83 (83·8%) were fluoroquinolone-resistant and composed of 51 (61·4%) extended-spectrum beta-lactamase (ESBL)-positive. Fluoroquinolone-resistant E. coli ratios were 73·4 and 95·9% before 2008 and after 2008, respectively (P = 0·002). The most sensitive antibiotics for fluoroquinolone-resistant E. coli strains were imipenem (100%), amikacin (84%) and cefoperazone (83%). The use of quinolones in the last 6 months and a history of hospitalization in the last 30 days were found to be significant risk factors. We found that resistant E. coli strains might be a common microorganism in patients with this kind of complication. The risk factors for development of infection with these resistant strains were history of the use of fluoroquinolones and hospitalization.

Prevalence, Risk Factors, and Clinical Relevance of Fluoroquinolone-Resistant Organisms in Rectal Cultures: Should We Target Antibiotic Prophylaxis Prior to Prostate Biopsy?

The rise of infectious complications after prostate biopsy has been linked to the growing resistance of enterobacteria to fluoroquinolone (FQ) antibiotics. In this review, we investigated the potential benefit of targeted antibiotic prophylaxis based on rectal cultures prior to prostate biopsy. An electronic search for all related literature published in English was performed from April until June 2015 using the MEDLINE and EMBASE databases. Data were obtained regarding the true prevalence of FQ-resistant bacteria in the rectum of patients, the identification of those patients at risk of harbouring FQ-resistant bacteria, the risk of infectious complications after transrectal prostate biopsy in patients with FQ-resistant bacteria, and the effect of targeted prophylaxis. Although there is limited evidence that a targeted approach might be beneficial, we conclude that current studies on the use of rectal cultures in the prebiopsy setting have too many limitations and confounding variables to definitely accept this approach in clinical practice. Whether this methodology is useful in a certain region will greatly depend on local fluoroquinolone-resistance rates.

Impact of fluoroquinolones on human microbiota. Focus on the emergence of antibiotic resistance

The aggregate of microorganisms residing on the surface of the skin, in the oropharynx and in the GI tract, known as the human microbiota, play a major role as natural reservoirs for bacterial resistance to antibiotics. Fluoroquinolones (FQ) are among the most prescribed antibiotics and a major increase in FQ resistance is occurring worldwide. High concentrations of FQ are found in microbial ecosystems explaining their profound effect on the clinically relevant bacteria that compose them. Yet, because of different local pharmacokinetics, distinct selective pressures occur in the different microbiota. Here we review the qualitative and quantitative impact of FQ on the three main human microbiota and their consequences, particularly in terms of emergence of antibiotic resistance. Finally, we review potential actions that could decrease the impact of FQs on microbiota.

Epidemiology and emerging resistance in bacterial bloodstream infections in patients with hematologic malignancies

BACKGROUND

The objective of this study was determine the frequency of bloodstream infections (BSIs) and the causative bacteria and their resistance patterns in patients with hematological malignancies (HMs) in a large tertiary care university hospital in Turkey over a 5-year period.

METHODS

A total of 2098 patients with HMs with 3703 neutropenic episodes were included. Patients were classified as high-risk (n = 843) and low-risk (n = 1255) groups and evaluated for frequency of BSIs, causative bacteria, and their resistance patterns.

RESULTS

The frequency of BSIs was 14.5%. The frequency of gram-negative BSIs in high-risk and low-risk groups was 10.7% and 5.4% (p < 0.001), respectively. The frequency of gram-positive BSIs in high-risk and low-risk groups was 7.0% and 3.9% (p < 0.001), respectively. Gram-negative bacteria predominated (52.6%), with Escherichia coli (17.3%) and Klebsiella spp. (11.0%) as the most frequent organisms. Coagulase-negative staphylococci (10.4%) and Corynebacterium spp. (6.3%) were the most common gram-positive bacteria (35.8%). The rate of extended-spectrum beta-lactamase (ESBL) production was 45% for E. coli and 58% for Klebsiella spp. Quinolone resistance was 58% for E. coli and 11% for Klebsiella spp.. The overall frequency of ceftazidime resistance in Pseudomonas aeruginosa was 28%, and 87% of Acinetobacter spp. were multidrug-resistant. Of Staphylococcus aureus isolates, 24.8% were resistant to methicillin.

CONCLUSION

The dominating causes of BSIs in patients with HMs in our hospital are resistant gram-negative bacteria, which has made empirical antimicrobial choice a highly challenging issue in this patient population.

Infection after transrectal ultrasound-guided prostate biopsy

Infectious complications after transrectal ultrasound-guided prostate biopsy (TRUS-Bx) appear to be increasing, which reflects the high prevalence of antibiotic-resistant strains of Enterobacteriaceae. Identifying patients at high risk for antibiotic resistance with history taking is an important initial step. Targeted prophylaxis with a prebiopsy rectal swab culture or augmented antibiotic prophylaxis can be considered for patients at high risk of antibiotic resistance. If infectious complications are suspected, the presence of urosepsis should be evaluated and adequate antibiotic treatment should be started immediately.

Clinical importance and epidemiology of quinolone resistance

The quinolone class of antimicrobial agents is one of most widely used classes of antimicrobial agents in outpatient and inpatient treatment. However, quinolone resistance in gram-positive and gram-negative bacteria has emerged and increased globally. This resistance limits the usefulness of quinolones in clinical practice. The review summarizes mechanisms of quinolone resistance and its epidemiology and implications in the most common clinical settings, urinary tract infections, respiratory tract infections, intraabdominal infections, skin and skin structure infections, and sexually transmitted diseases.

Risk factor of community-onset spontaneous bacterial peritonitis caused by fluoroquinolone-resistant Escherichia coli in patients with cirrhosis

BACKGROUND & AIMS

Despite the high prevalence of antimicrobial-resistant Escherichia coli in hospital-acquired infections, the clinical epidemiology of fluoroquinolone (FQ) resistance in community-onset spontaneous bacterial peritonitis (SBP) in patients with cirrhosis is not well understood. This study was performed to evaluate clinical features and risk factors for community-onset SBP caused by FQ-resistant E. coli.

METHODS

A case-control control study was performed using cases of community-onset SBP from June 2000 to August 2011 at Samsung Medical Center (Seoul, Korea). Patients with FQ-resistant E. coli were designated as case patients. A control group I (CG I) patient was defined as a person whose clinical sample yielded FQ-susceptible E. coli, and a control group II (CG II) patient was defined as a person with a negative culture result.

RESULTS

A total of 82 subjects with community-onset SBP caused by E. coli were identified, of which 26 (31.7%) were FQ-resistant E. coli infection. Fifty-seven matched subjects were randomly selected for CG II. Compared with CG I, previous SBP episodes (OR, 4.91; 95% CI, 1.50-16.53; P = 0.010), prior use of FQ within 30 days (OR, 7.05; 95% CI, 1.17-42.38; P = 0.033), and third-generation cephalosporin resistance (OR, 17.68; 95% CI, 1.67-187.26; P = 0.017) were significantly associated with FQ-resistant E. coli. Compared with CG II, a previous SBP episode was significantly associated with FQ-resistant E. coli (OR, 4.20; 95% CI, 1.50-11.80; P = 0.006).

CONCLUSION

FQ-resistant E. coli is a significant cause of community-onset SBP, with relation to previous SBP episodes, recent FQ use and third-generation cephalosporin resistance.

Impact of antibiotic use during hospitalization on the development of gastrointestinal colonization with Escherichia coli with reduced fluoroquinolone susceptibility

OBJECTIVE

Infections due to fluoroquinolone-resistant Escherichia coli (FQREC) are associated with significant morbidity and mortality. Fluoroquinolone resistance likely arises at the level of gastrointestinal colonization. The objective of this study was to identify risk factors for the development of FQREC gastrointestinal tract colonization in hospitalized patients, including the impact of antibiotics prescribed during hospitalization.

DESIGN

A prospective cohort study was conducted from 2002 to 2004 within a university health system.

METHODS

Hospitalized patients initially colonized with fluoroquinolone-susceptible E. coli were followed up with serial fecal sampling for new FQREC colonization or until hospital discharge or death. A Cox proportional hazards regression model was developed to identify risk factors for new FQREC colonization, with antibiotic exposure modeled as time-varying covariates.

RESULTS

Of 395 subjects, 73 (18.5%) became newly colonized with FQREC. Length of stay before sampling (hazard ratio [HR], 1.02 [95% confidence interval (CI), 1.1-1.03]; P = .003) and malignancy (HR, 0.37 [95% CI, 0.21-0.67]; P = .001) were significantly associated with the development of FQREC colonization. In addition, receipt of a first-generation cephalosporin (HR, 1.19 [95% CI, 1.10-1.29]; P < .001) or cefepime (HR, 1.05 [95% CI, 1.00-1.10]; P = .048) during hospitalization increased the risk of new FQREC colonization.

CONCLUSIONS

The acquisition of FQREC in the hospital setting is complex, and antimicrobial stewardship programs should take into account patterns of antibiotic use in implementing strategies to reduce the development of new FQREC colonization. Future studies are needed to identify risk factors for infection in hospitalized patients newly colonized with FQREC.

Do we really know the prevalence of multi-drug resistant Escherichia coli in the territorial and nosocomial population?

Introduction:

The purpose of this work was to evaluate the prevalence of the Quinolones resistant Escherichia coli and/or ESBL producers in the population of our catchment area and hospital component.

Materials and Methods:

From January 2008 to December 2010, all data concerning urine cultures in patients with suspected urinary tract infection and/or asymptomatic bacteriuria referring at our center located in the south of Milan were prospectively evaluated.

Results:

In 2008, 2136 outpatient and 1232 hospital urine cultures were analyzed. The presence of quinolone-resistant strains was 21% at a local level and 53% in hospitals. ESBL-producing strains were isolated in 3.5% of cases at a local level and 20.5% in hospitals. In 2009, 2396 outpatient and 1320 hospital urine cultures were analyzed. The presence of quinolone-resistant strains was 21% at a local level and 46% in hospitals. ESBL-producing strains were isolated in 5.4% of cases at a local level and 20% in hospitals. In 2010, 2601 outpatient and 1717 hospital urine cultures were analyzed. The presence of quinolone-resistant strains was 34% at a local level and 26% in hospitals. ESBL-producing strains were isolated in 6.7% of cases at a local level and 20.6% in hospitals. The multidrug resistance was significantly (P < 0.01) higher in ESBL-positive strains.

Conclusion:

Due to rising antibiotic resistance among uropathogens, it is important to have knowledge of the organisms causing urinary tract infections and their antibiotic sensitivity patterns. In areas with high prevalence of E. Coli resistance, performing urine culture before every surgical procedure became mandatory, in order to prevent fatal sepsis.

Ciprofloxacin resistance in the faecal carriage of patients undergoing transrectal ultrasound guided prostate biopsy

WHAT'S KNOWN ON THE SUBJECT? AND WHAT DOES THE STUDY ADD?: Transrectal ultrasound guided prostate biopsies (TRUSBx) are associated with a spectrum of complications, including most significantly infection, which affects up to 5% of patients. In the most severe cases, infection leads to sepsis, a life-threatening complication. Escherichia coli is the primary responsible pathogen. Although antibiotic prophylaxis with fluoroquinolones is routinely used, there is evidence that the infection rate after TRUSBx is increasing, and this appears to be due to an increasing prevalence of ciprofloxacin-resistant rectal flora. This is the largest prospective clinical trial to date analysing the rectal flora of men undergoing prostate biopsies. We determined the microbial and antibiotic sensitivity profiles from 849 patients. Ciprofloxacin-resistant Gram-negative organisms were identified in the rectal flora of 19.0% of men. Furthermore, fluoroquinolone use within 6 months preceding a TRUSBx and the presence of a prosthetic heart valve were significant predictors of ciprofloxacin resistance on rectal swab. Determining the prevalence of rectal fluoroquinolone resistance has important implications in evaluation of the suitability of prophylactic regimens. Antimicrobial profiles derived from rectal swabs pre-biopsy may prove useful in guiding targeted antibiotic prophylaxis.

OBJECTIVES

To establish the prevalence of ciprofloxacin-resistant bacteria in patients undergoing transrectal ultrasound guided prostate biopsies (TRUSBx) and to determine whether this predicts subsequent infectious complications. To identify risk factors for harbouring ciprofloxacin-resistant flora.

PATIENTS AND METHODS

Any patient undergoing a TRUSBx from 2009 to 2011 was eligible for enrolment in this prospective study. Pre-biopsy rectal and urine cultures and post-biopsy urine cultures were obtained and antimicrobial susceptibility was determined. Univariate and multivariate analyses were performed to identify independent patient risk factors associated with ciprofloxacin-resistant rectal flora.

RESULTS

A total of 865 patients underwent TRUSBx, of whom 19.0% were found to have ciprofloxacin-resistant Gram-negative coliforms. Escherichia coli was the most prevalent Gram-negative rectal isolate (80.9%) and accounted for 90.6% of ciprofloxacin resistance. Patient characteristics that conferred an increased risk of harbouring ciprofloxacin-resistant organisms included a history of a heart valve replacement (P < 0.05) and ciprofloxacin use in the past 3 months (P < 0.05). Infectious complications were observed in 3.6% (n = 31) of the patient population and 48% of these patients grew ciprofloxacin-resistant organisms on the pre-biopsy rectal swab (P < 0.001).

CONCLUSIONS

Antimicrobial resistance to ciprofloxacin in the rectal flora was common, particularly in patients with recent ciprofloxacin use and a heart valve replacement. Despite a significant correlation between those patients who developed infections and the detection of ciprofloxacin-resistant organisms, only 9.0% (n = 15) of the total group with ciprofloxacin resistance developed an infectious complication. Future studies will need to evaluate the cost effectiveness and clinical utility of a pre-biopsy rectal culture in targeting antibiotic prophylaxis.

Oral antibiotics for fever in low-risk neutropenic patients with cancer: a double-blind, randomized, multicenter trial comparing single daily moxifloxacin with twice daily ciprofloxacin plus amoxicillin/clavulanic acid combination therapy--EORTC infectious diseases group trial XV

PURPOSE

This double-blind, multicenter trial compared the efficacy and safety of a single daily oral dose of moxifloxacin with oral combination therapy in low-risk febrile neutropenic patients with cancer.

PATIENTS AND METHODS

Inclusion criteria were cancer, febrile neutropenia, low risk of complications as predicted by a Multinational Association for Supportive Care in Cancer (MASCC) score > 20, ability to swallow, and ≤ one single intravenous dose of empiric antibiotic therapy before study drug treatment initiation. Early discharge was encouraged when a set of predefined criteria was met. Patients received either moxifloxacin (400 mg once daily) monotherapy or oral ciprofloxacin (750 mg twice daily) plus amoxicillin/clavulanic acid (1,000 mg twice daily). The trial was designed to show equivalence of the two drug regimens in terms of therapy success, defined as defervescence and improvement in clinical status during study drug treatment (< 10% difference).

RESULTS

Among the 333 patients evaluated in an intention-to-treat analysis, therapy success was observed in 80% of the patients administered moxifloxacin and in 82% of the patients administered combination therapy (95% CI for the difference, -10% to 8%, consistent with equivalence). Minor differences in tolerability, safety, and reasons for failure were observed. More than 50% of the patients in the two arms were discharged on protocol therapy, with 5% readmissions among those in either arm. Survival was similar (99%) in both arms.

CONCLUSION

Monotherapy with once daily oral moxifloxacin is efficacious and safe in low-risk febrile neutropenic patients identified with the help of the MASCC scoring system, discharged early, and observed as outpatients.

Antimicrobial susceptibility profiles of Gram-negative bacilli isolated from patients with hepatobiliary infections in Taiwan: results from the Study for Monitoring Antimicrobial Resistance Trends (SMART), 2006-2010

We investigated the trends in antimicrobial resistance among species of Gram-negative bacilli isolated from patients with hepatobiliary tract infections in Taiwan during the period 2006-2010 as part of the Study for Monitoring Antimicrobial Resistance Trends (SMART). During the study period, 1032 isolates of Gram-negative bacilli that had been collected from patients with hepatobiliary infections were tested for susceptibility to 12 antimicrobial agents in accordance with the Clinical and Laboratory Standards Institute guidelines. Enterobacteriaceae accounted for the majority (n = 874, 84.7%) of isolates and Escherichia coli was the most common pathogen (n = 323, 31.3%). There were significantly more E. coli (P = 0.001) and Proteus mirabilis (P = 0.031) isolates collected from patients who had been hospitalized for less than 48 h and significantly more Serratia marcescens (P = 0.035) and Pseudomonas aeruginosa (P = 0.008) isolates collected from patients who had been hospitalized for 48 h or longer. The prevalence of extended-spectrum β-lactamase (ESBL)-producing pathogens was low. The decline in susceptibility rates with time was remarkable for ceftazidime (P = 0.036), ciprofloxacin (P = 0.029), and levofloxacin (P = 0.018). The most effective antibiotics, i.e., those that were active against more than 90% of Enterobacteriaceae, were amikacin, cefepime, imipenem, ertapenem, and piperacillin-tazobactam. Susceptibility of P. aeruginosa to anti-pseudomonal agents was greater than 80%. In this study, we found an overall increase in resistance to antimicrobial agents among Gram-negative bacilli isolated from patients with hepatobiliary tract infections in Taiwan. Surveillance of antimicrobial susceptibility and updates of treatment guidelines are recommended to help achieve optimal therapy for patients with hepatobiliary infections.

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.

Fluoroquinolone-resistant E. coli in intestinal flora of patients undergoing transrectal ultrasound-guided prostate biopsy--should we reassess our practices for antibiotic prophylaxis?

Although the estimate of the incidence of sepsis following transrectal ultrasound-guided prostate biopsy (TRUSPB) is low, fluoroquinolone-resistant infections after prostate biopsy are being increasingly noted. This study was aimed at determining the prevalence of faecal carriage of fluoroquinolone-resistant Escherichia coli strains before TRUSPB and at evaluating potential predisposing risk factors. The incidence of sepsis after prostate biopsy was determined, and our routine practice for antibiotic prophylaxis for TRUSPB was evaluated. A prospective study was conducted in 342 consecutive patients undergoing prostate biopsy between December 2009 and July 2010. Before TRUSPB, a rectal swab was cultured. The correlation between the presence of fluoroquinolone-resistant strains and plausible risk factors was investigated by the use of a questionnaire. Of the 236 patients included, 22.0% (52/236) harboured ciprofloxacin-resistant E. coli strains. The use of fluoroquinolones in the 6 months before biopsy was associated with an increased risk of faecal carriage of fluoroquinolone-resistant E. coli strains (p <0.01). Faecal carriage of fluoroquinolone-resistant E. coli strains was an important risk factor for infectious complications after TRUSPB (p <0.01). In conclusion, a significant number of patients have faecal carriage of fluoroquinolone-resistant E. coli strains (22.0%) before TRUSPB. The use of fluoroquinolones in the previous 6 months before biopsy is a risk factor for faecal carriage of fluoroquinolone-resistant E. coli strains and for infectious complications after TRUSPB. Hence, the universal administration of fluoroquinolones should be reconsidered.

Rising incidence of acute prostatitis following prostate biopsy: fluoroquinolone resistance and exposure is a significant risk factor

OBJECTIVE

To evaluate the frequency and potential risk factors for infection-related complications after transrectal prostate biopsy and to propose adjustments in current antimicrobial prophylaxis recommendations.

METHODS

During 2008-2010, 107 patients underwent transrectal ultrasound-guided biopsies of the prostate at our institution. Charts were reviewed for infection-related complications within 30 days of the procedure. Potential risk factors were evaluated, including age, diabetes mellitus, chronic constipation/diverticular disease, prior use of quinolones, enema and prostatitis, on the pathology report. For patients with acute prostatitis, urine and blood samples were assessed for bacteriology and antibiotic susceptibility.

RESULTS

Of our 107 patients, acute prostatitis developed in 10 (9.3%). The most significant risk factor was prior use of a fluoroquinolone antimicrobial, with acute prostatitis developing in 7 (17.1%) of 41 patients who had used a fluoroquinolone compared with 3 (4.5%) of 66 patients who had not (P=.042). Patients who received an enema before the procedure were slightly less likely to develop prostatitis (P=.061). Of 8 positive specimens, the organisms isolated were Escherichia coli in 6, Klebsiella pneumoniae in 1, and Staphylococcus epidermidis in one. Isolated Gram-negative organisms were fluoroquinolone-resistant in 85.7% of samples.

CONCLUSION

Prior fluoroquinolone intake is a significant risk factor behind a rising incidence of acute prostatitis after transrectal prostate biopsy. Identified pathogens are mostly Gram-negative organisms with a high rate of fluoroquinolone resistance. Alternative prophylaxis regimens for the biopsy procedure should be considered in patients with recent quinolone intake.

Antimicrobial resistance in more than 100,000 Escherichia coli isolates according to culture site and patient age, gender, and location

Escherichia coli and the antimicrobial pressure exerted on this microorganism can be modulated by factors dependent on the host. In this paper, we describe the distribution of antimicrobial resistance to amikacin, tobramycin, ampicillin, amoxicillin clavulanate, cefuroxime, cefoxitin, cefotaxime, imipenem, ciprofloxacin, fosfomycin, nitrofurantoin, and trimetoprim-sulfametoxazole in more than 100,000 E. coli isolates according to culture site and patient age, gender, and location. Bayesian inference was planned in all statistical analysis, and Markov chain Monte Carlo simulation was employed to estimate the model parameters. Our findings show the existence of a marked difference in the susceptibility to several antimicrobial agents depending on from where E. coli was isolated, with higher levels of resistance in isolates from medical devices, the respiratory system, and the skin and soft tissues; a higher resistance percentage in men than in women; and the existence of a clear difference in antimicrobial resistance with an age influence that cannot be explained merely by means of an increase of resistance after exposure to antimicrobials. Both men and women show increases in resistance with age, but while women show constant levels of resistance or slight increases during childbearing age and greater increases in the premenopausal age, men show a marked increase in resistance in the pubertal age. In conclusion, an overwhelming amount of data reveals the great adaptation capacity of E. coli and its close interaction with the host. Sex, age, and the origin of infection are determining factors with the ability to modulate antimicrobial resistances.

The impact of a nationwide antibiotic restriction program on antibiotic usage and resistance against nosocomial pathogens in Turkey

PURPOSE

Antimicrobial resistance among microorganisms is a global concern. In 2003, a nationwide antibiotic restriction program (NARP) was released in Turkey. In this study we evaluated the effect of NARP on antibiotic consumption, antimicrobial resistance, and cost.

MATERIALS AND METHODS

The data obtained from all of the four university hospitals, and one referral tertiary-care educational state hospital in Ankara. Antimicrobial resistance profiles of 14,233 selected microorganisms all grown in blood cultures and antibiotic consumption from 2001 to 2005 were analyzed retrospectively.

RESULTS

A negative correlation was observed between the ceftriaxone consumption and the prevalence of ceftriaxone resistant E.coli and Klebsiella spp. (rho:-0.395, p:0.332 and rho:-0.627, p:0.037, respectively). The decreased usage of carbapenems was correlated with decreased carbapenems-resistant Pseudomonas spp. and Acinetobacter spp (rho:0.155, p:0.712 and rho:0.180, p:0.668, respectively for imipenem). Methicillin resistance rates of S.aureus were decreased from 44% to 41%. After two years of NARP 5,389,155.82 USD saving occurred.

CONCLUSION

NARP is effective in lowering the costs and antibiotic resistance.

Detection of fluoroquinolone-resistant organisms from rectal swabs by use of selective media prior to a transrectal prostate biopsy

Sepsis caused by fluoroquinolone-resistant Escherichia coli is a risk for patients undergoing an ultrasound-guided, transrectal prostate biopsy. A method incorporating selective broth and media was evaluated using rectal swabs obtained from 136 patients prior to a biopsy procedure. Fluoroquinolone-resistant organisms were isolated from 22% of the patients included in this study.

Risk factors for dogs becoming rectal carriers of multidrug-resistant Escherichia coli during hospitalization

This study aimed to identify risk factors for dogs becoming rectal carriers of multidrug-resistant (MDR) Escherichia coli while hospitalized in a veterinary teaching hospital. Exposures to potential risk factors, including treatments, hospitalization, and interventions during a 42-day pre-admission period and hospitalization variables, were assessed for 90 cases and 93 controls in a retrospective, risk-based, case-control study. On multivariable analyses, hospitalization for >6 days [odds ratio (OR) 2·91-8·00], treatment with cephalosporins prior to admission (OR 5·04, 95% CI 1·25-20·27), treatment with cephalosporins for >1 day (OR 5·18, 95% CI 1·86-14·41), and treatment with metronidazole (OR 7·17, 95% CI 1·01-50·79) while hospitalized were associated with increased risk of rectal carriage of MDR E. coli during hospitalization. The majority of rectal isolates obtained during the study period conformed to MDR E. coli clonal groups previously obtained from extraintestinal infections. These results can assist the development of improved infection control guidelines for the management of dogs in veterinary hospitals to prevent the occurrence of nosocomial clinical infections.

A randomized comparative study of single-dose fosfomycin and 5-day ciprofloxacin in female patients with uncomplicated lower urinary tract infections

Uncomplicated lower urinary tract infections (UTIs) are the most frequent infections in females. Increased resistance rates against commonly used antibiotics have led to the use of novel antimicrobials. The aim of the present study was to evaluate the bacteriological and clinical effects of single-dose fosfomycin trometamol (FMT) and 5-day ciprofloxacin in females with uncomplicated UTIs. In this randomized comparative study, 260 female patients between 18 and 65 years of age enrolled, of whom 142 completed the study. The most frequently isolated bacterial pathogen in the urine cultures of patients were Escherichia coli (82.3%) and Enterobacter spp. (8.4%). FMT sensitivity was 94% and ciprofloxacin sensitivity was 59% in Escherichia coli; in comparison, FMT sensitivity was 75% and ciprofloxacin sensitivity was 50% in Enterobacter spp. The MIC90 for FMT was 4 μg/ml. Of the 142 patients, 77 were treated with FMT and 65 were treated with ciprofloxacin. The clinical remission rate was 83% in the FMT group and 81% in the ciprofloxacin group; the bacterial eradication rate was 83% in the FMT group and 78% in the ciprofloxacin group, and there was no significant difference between the two study groups. In conclusion, a single dose of FMT (at 3 g) was as effective as ciprofloxacin, at 500 mg twice a day for 5 days, in the treatment of uncomplicated lower UTIs. It was concluded that the use of FMT as a first-line treatment in the empirical treatment of uncomplicated UTIs might have a positive impact on the problem of resistance to other antibiotics.

Emergence of resistant Klebsiella pneumoniae in the intestinal tract during successful treatment of Klebsiella pneumoniae lung infection in rats

Antibiotic treatment of lung infections may lead to the emergence of resistance in the gut flora. Appropriate dosing regimens could mitigate this adverse effect. In gnotobiotic rats harboring intestinal Escherichia coli and Enterococcus faecium populations, a lung infection by Klebsiella pneumoniae was instigated with two different sizes of inoculum to represent an early or a late initiation of antibiotic treatment. The rats were treated with marbofloxacin, an expanded-spectrum fluoroquinolone, by a single-shot administration or a fractionated regimen over 4 days. Intestinal bacterial populations were monitored during and after treatment. At the infection site, bacterial cure without any selection of resistance was observed. Whatever the dosage regimen, fluoroquinolone treatment had a transient negative impact on the E. coli gut population but not on that of E. faecium. The intestinal flora was colonized by the pathogenic lung bacteria, and there was the emergence of intestine-resistant K. pneumoniae, occurring more often in animals treated with a single marbofloxacin dose than with the fractionated dose. Bacterial cure without resistance selection at the infection site with fluoroquinolone treatment can be linked to colonization of the digestive tract by targeted pulmonary bacteria, followed by the emergence of resistance.

Risk factors for multidrug-resistant Escherichia coli rectal colonization of dogs on admission to a veterinary hospital

This study aimed to identify risk factors for intestinal colonization with multidrug-resistant (MDR) E. coli in dogs on admission to a veterinary teaching hospital. Exposures to potential risk factors, including prior treatments, hospitalizations and interventions during the 42 days prior to admission were assessed for 82 case admissions and 82 time-matched controls in a retrospective prevalence-based case-control study of 20 months duration. On multivariable analyses, risk of MDR E. coli colonization on admission was increased with prior hospitalization for 4-7 days and >7 days relative to shorter periods, and in dogs that had prior diagnostic imaging techniques. Univariable analyses indicated that risk was increased following prior treatment with several antimicrobial agents. However, on multivariable analysis, administration of fluoroquinolones was associated with increased risk but risk did not appear to increase following administration of other antimicrobials. These results can inform management of canine patients and infection control procedures to mitigate the risk of clinical disease due to MDR bacteria in hospitalized dogs.