Antimicrobial resistance trends of Escherichia coli bloodstream isolates: a population-based study, 1998-2007

Evaluation of Emerging Antimicrobials Resistance in Nosocomial Infections Caused by E. coli: The Comparison Results of Observed Cases and Compartmental Model

Background: In recent years, the global rise of antibiotic-resistant Escherichia coli (E. coli) has become a significant threat to public health. This study aimed to identify and track outbreaks of antibiotic resistance, specifically among the antibiotics used to treat nosocomial E. coli infections. Materials and Methods: This hospital-based study utilized data from a nosocomial infection surveillance system to investigate reported cases of antibiotic resistance. The study analyzed the results of 12,954 antibiogram tests conducted across 57 hospitals in 31 provinces of Iran. The data was divided into two periods: the first and second halves of 2017. Before developing a predictive model for resistant E. coli cases, the model's validity was tested using the first half of the year's data. The predicted cases were then compared to the actual observed cases in 2017, with a statistically significant difference indicating an outbreak. Findings: The study found that, in 2017, hospitals in Iran experienced an outbreak of E. coli resistant to ampicillin and ceftazidime. This resistance was more prevalent than expected, highlighting the emergence of these drugs as major contributors to nosocomial E. coli infections. Conclusion: This study demonstrated the utility of the compartmental model in forecasting outbreaks of antibiotic-resistant E. coli. It provides a framework for investigating similar outbreaks in the future, using diverse data sources and methodologies.

Bayesian estimation of the prevalence of antimicrobial resistance: a mathematical modelling study

BACKGROUND

Estimates of the prevalence of antimicrobial resistance (AMR) underpin effective antimicrobial stewardship, infection prevention and control, and optimal deployment of antimicrobial agents. Typically, the prevalence of AMR is determined from real-world antimicrobial susceptibility data that are time delimited, sparse, and often biased, potentially resulting in harmful and wasteful decision-making. Frequentist methods are resource intensive because they rely on large datasets.

OBJECTIVES

To determine whether a Bayesian approach could present a more reliable and more resource-efficient way to estimate population prevalence of AMR than traditional frequentist methods.

METHODS

Retrospectively collected, open-source, real-world pseudonymized healthcare data were used to develop a Bayesian approach for estimating the prevalence of AMR by combination with prior AMR information from a contextualized review of literature. Iterative random sampling and cross-validation were used to assess the predictive accuracy and potential resource efficiency of the Bayesian approach compared with a standard frequentist approach.

RESULTS

Bayesian estimation of AMR prevalence made fewer extreme estimation errors than a frequentist estimation approach [n = 74 (6.4%) versus n = 136 (11.8%)] and required fewer observed antimicrobial susceptibility results per pathogen on average [mean = 28.8 (SD = 22.1) versus mean = 34.4 (SD = 30.1)] to avoid any extreme estimation errors in 50 iterations of the cross-validation. The Bayesian approach was maximally effective and efficient for drug-pathogen combinations where the actual prevalence of resistance was not close to 0% or 100%.

CONCLUSIONS

Bayesian estimation of the prevalence of AMR could provide a simple, resource-efficient approach to better inform population infection management where uncertainty about AMR prevalence is high.

Genomic Dissection of an Enteroaggregative Escherichia coli Strain Isolated from Bacteremia Reveals Insights into Its Hybrid Pathogenic Potential

Escherichia coli is a frequent pathogen isolated from bloodstream infections. This study aimed to characterize the genetic features of EC092, an E. coli strain isolated from bacteremia that harbors enteroaggregative E. coli (EAEC) genetic markers, indicating its hybrid pathogenic potential. Whole-genome sequencing showed that EC092 belongs to phylogroup B1, ST278, and serotype O165:H4. Genes encoding virulence factors such as fimbriae, toxins, iron-uptake systems, autotransporter proteins (Pet, Pic, Sat, and SepA), and secretion systems were detected, as well as EAEC virulence genes (aggR, aatA, aaiC, and aap). EC092 was found to be closely related to the other EAEC prototype strains and highly similar in terms of virulence to three EAEC strains isolated from diarrhea. The genomic neighborhood of pet, pic, sat, sepA, and the EAEC virulence genes of EC092 and its three genetically related fecal EAEC strains showed an identical genomic organization and nucleotide sequences. Also, EC092 produced and secreted Pet, Pic, Sat, and SepA in the culture supernatant and resisted the bactericidal activity of normal human serum. Our results demonstrate that the strain EC092, isolated from bacteremia, is a hybrid pathogenic extraintestinal E. coli (ExPEC)/EAEC with virulence features that could mediate both extraintestinal and intestinal infections.

[Nine-year trend in Escherichia coli resistance to ciprofloxacin: cross-sectional study in a hospital in Colombia]

Ciprofloxacin is a critically important antibiotic for human health. The increase of Escherichia coli resistance to ciprofloxacin is a global public health problem due to its importance in the treatment of complicated urinary tract infections and other serious infections; however, its prescription is high in the Colombian Caribbean. The objective was to determine the resistance trend of E. coli to ciprofloxacin in a Colombian hospital of high complexity. From antibiogram reports, isolates were categorized according to Clinical and Laboratory Standards Institute criteria for each year studied; proportions were calculated and differences in sensitivity were explored using the χ2 test. The Cochran-Armitage test was used to evaluate the resistance trend. Significance was considered when p-value ≤ 0.05. In total, 6,848 isolates were analyzed, and 49.31% resistance was found. According to origin, the highest resistance was in community samples (51.96% - 95%CI: 50.51; 53.41), and by type of sample, in skin and tissues (61.76% - 95%CI: 56.96; 66.35) and urine (48.97% - 95%CI: 47.71; 50.23). Increasing trends were observed for resistance per year (p < 0.0001), community samples (p = 0.0002) and urine (p < 0.0001). Resistance to ciprofloxacin is high and tends to increase in the community and in urine, exceeding the limit established for its use at the ambulatory level, which is of concern due to the high prescription of fluoroquinolones in the locality.

Safety, Reactogenicity, Immunogenicity, and Dose Selection of 10-Valent Extraintestinal Pathogenic Escherichia coli Bioconjugate Vaccine (VAC52416) in Adults Aged 60-85 Years in a Randomized, Multicenter, Interventional, First-in-Human, Phase 1/2a Study

Background

ExPEC10V is a bioconjugate vaccine containing O-antigen polysaccharides of 10 extraintestinal pathogenic Escherichia coli (ExPEC) serotypes. This phase 1/2a study (NCT03819049) assessed the safety, reactogenicity, and immunogenicity of ExPEC10V (VAC52416) to prevent invasive E coli disease in elderly adults.

Methods

The observer-blind, active-controlled design included a 28-day screening, vaccination, 181-day follow-up, and 1-year follow-up. Participants (60-85 years of age) were randomized to ExPEC10V low dose (antigen dose range, 4-8 µg), ExPEC10V medium dose (4-16 µg), or ExPEC10V high dose (8-16 µg); 4-valent ExPEC vaccine (ExPEC4V); or 13-valent pneumococcal conjugate vaccine (PCV13). The incidence of adverse events (AEs; solicited, day 15; unsolicited, day 30; serious AEs, day 181) and immunogenicity (electrochemiluminescent-based assay [ECL] and multiplex opsonophagocytic assay [MOPA]) were assessed. Optimal ExPEC10V dose was determined from safety data through day 30 and an immunogenicity dose selection algorithm based on day 15 ECL and MOPA results.

Results

A total of 416 participants were included (median age, 64.0 years; 54.8% female). The incidences of solicited local and systemic AEs were, respectively, 44.2% and 39.4% for low-dose, 52.9% and 46.1% for medium-dose, 57.7% and 45.2% for high-dose ExPEC10V, and 74.1% and 48.1% for PCV13. Five serious AEs, not vaccine related, were reported. The ECL revealed a robust antibody response to ExPEC10V through year 1. Opsonophagocytic killing activity was detected against all but serotype O8; this lack of response against serotype O8 was linked to low assay sensitivity. Based on the totality of data, high-dose ExPEC10V was considered optimal.

Conclusions

ExPEC10V was well tolerated and immunogenic in elderly adults against all but serotype O8.

Antimicrobial resistance prevalence of Escherichia coli and Staphylococcus aureus amongst bacteremic patients in Africa: a systematic review

OBJECTIVES

Antimicrobial resistance (AMR) is a global concern among infectious diseases. Bloodstream infections can potentially become life-threatening if they become untreatable with conventional antimicrobials. This review aims to provide an understanding of the AMR prevalence and trends of common bacteremic pathogens, namely Escherichia coli and Staphylococcus aureus in the World Health Organization (WHO) Africa region.

METHODS

PubMed and Google Scholar were searched using relevant keywords for published human studies (excluding case reports and reviews) reporting bacteremic AMR data on the pathogens of interest between 2008 and 2019. Two reviewers independently screened the articles against a pre-defined eligibility criterion. Data extraction and analysis were achieved with different platforms: Covidence, Excel, R version 3.6.3, and QGIS v3.4.5. The pooled prevalence, 95% confidence intervals, and I² index (a measure of heterogeneity) were calculated for the various pathogen-antibiotic combinations.

RESULTS

Five hundred sixty-two papers were retrieved, with 27 papers included in the final analysis. Only 23.4% (11/47) of member states of the WHO African region had reports on AMR in bacteremia. The Clinical and Laboratory Standards Institute (CLSI) (78.5%) was the most common standard used in the region. For E. coli, the pooled resistance was: cefotaxime (42%), imipenem (4%), meropenem (0%), and colistin (0%). For S. aureus, the calculated pooled resistance was cloxacillin (34%), oxacillin (12%), and vancomycin (0%). There was a high degree of variation across studies (I² > 90%).

CONCLUSION

The pooled resistance rates indicate a concerning degree of methicillin-resistant and Extended Spectrum-ß-lactamase-producing pathogens. The paucity of AMR data also presents challenges for a comprehensive understanding of the situation in the region. Continent-wide and standardized surveillance efforts therefore need strengthening.

Revisiting β-Lactams for Treatment of Urinary Tract Infections: Assessing Clinical Outcomes of Twice-Daily Cephalexin for Empiric Treatment of Uncomplicated Urinary Tract Infections

The 2011 Infectious Diseases Society of America guidelines for treatment of uncomplicated urinary tract infections (UTIs) recommend non-β-lactam antibiotics for empiric therapy. However, increasing Escherichia coli and Klebsiella spp. resistance to first-line antibiotic therapies has necessitated the need for alternative agents. Based on local antibiogram data, cephalexin has become the preferred oral antibiotic for empiric treatment of UTIs at our institution. The purpose of this single-center retrospective review was to assess clinical outcomes of patients discharged from the emergency department (ED) who received cephalexin for the treatment of uncomplicated UTIs. The primary outcome of this study was to assess the proportion of patients with clinical success 30 days after discharge from the ED. Patients were excluded if they were <18 years of age, received ≥10 days of cephalexin, received antibiotics for any indication other than uncomplicated UTI, received antibiotics within 60 days of their ED visit, or had structural abnormalities. A total of 264 patients were included for evaluation, and 214 patients (81.1%) met the criteria for clinical success. Overall, 28 (10.6%) patients required a change in antibiotics based on cultures and sensitivities, 18 (6.8%) patients returned for nonresolving or worsening symptoms, and 4 (1.5%) patients required both a change in antibiotics and returned for nonresolving or worsening symptoms. Short courses of twice-daily cephalexin appear to be a safe and effective option for the empiric treatment of uncomplicated UTIs.

Epidemiology, Clinical Features, and Antimicrobial Resistance of Invasive Escherichia Coli Disease in Patients Admitted in Tertiary Care Hospitals

Background

Invasive Escherichia coli disease (IED), including bloodstream infection, sepsis, and septic shock, can lead to high hospitalization and mortality rates. This multinational study describes the clinical profile of patients with IED in tertiary care hospitals.

Methods

We applied clinical criteria of systemic inflammatory response syndrome (SIRS), sepsis, or septic shock to patients hospitalized with culture-confirmed E coli from urine or a presumed sterile site. We assessed a proposed clinical case definition against physician diagnoses.

Results

Most patients with IED (N = 902) were adults aged ≥60 years (76.5%); 51.9%, 25.1%, and 23.0% of cases were community-acquired (CA), hospital-acquired (HA), and healthcare-associated (HCA), respectively. The urinary tract was the most common source of infection (52.3%). Systemic inflammatory response syndrome, sepsis, and septic shock were identified in 77.4%, 65.3%, and 14.1% of patients, respectively. Patients >60 years were more likely to exhibit organ dysfunction than those ≤60 years; this trend was not observed for SIRS. The case-fatality rate (CFR) was 20.0% (60-75 years, 21.5%; ≥75 years, 22.2%), with an increase across IED acquisition settings (HA, 28.3%; HCA, 21.7%; CA, 15.2%). Noticeably, 77.8% of patients initiated antibiotic use on the day of culture sample collection. A total of 65.6% and 40.8% of E coli isolates were resistant to ≥1 agent in ≥1 or ≥2 drug class(es). A 96.1% agreement was seen between the proposed clinical case definition and physician's diagnoses of IED.

Conclusions

This study contributes valuable, real-world data about IED severity. An accepted case definition could promote timely and accurate diagnosis of IED and inform the development of novel preventative strategies.

Prescribing for different antibiotic classes across age groups in the Kaiser Permanente Northern California population in association with influenza incidence, 2010-2018

There is limited information on the volume of antibiotic prescribing that is influenza-associated, resulting from influenza infections and their complications (such as streptococcal pharyngitis). We estimated that for the Kaiser Permanente Northern California population during 2010-2018, 3.4% (2.8%-4%) of all macrolide prescriptions (fills), 2.7% (2.3%-3.2%) of all aminopenicillin prescriptions, 3.1% (2.4%-3.9%) of all 3rd generation cephalosporins prescriptions, 2.2% (1.8%-2.6%) of all protected aminopenicillin prescriptions and 1.3% (1%-1.6%) of all quinolone prescriptions were influenza-associated. The corresponding proportions were higher for select age groups, e.g. 4.3% of macrolide prescribing in ages over 50 years, 5.1% (3.3%-6.8%) of aminopenicillin prescribing in ages 5-17 years and 3.3% (1.9%-4.6%) in ages <5 years was influenza-associated. The relative contribution of influenza to antibiotic prescribing for respiratory diagnoses without a bacterial indication in ages over 5 years was higher than the corresponding relative contribution to prescribing for all diagnoses. Our results suggest a modest benefit of increasing influenza vaccination coverage for reducing prescribing for the five studied antibiotic classes, particularly for macrolides in ages over 50 years and aminopenicillins in ages <18 years, and the potential benefit of other measures to reduce unnecessary antibiotic prescribing for respiratory diagnoses with no bacterial indication, both of which may contribute to the mitigation of antimicrobial resistance.

Outpatient transperineal prostate biopsy under local anaesthesia is safe, well tolerated and feasible

BACKGROUND

Transperineal biopsy (TPB) of the prostate has been increasingly utilized as it has reduced infection risks. Traditionally however, it is performed under general anaesthesia, thus it carries a differing set of risks. Recently, new studies have performed TPB under local anaesthesia with success. In the present study, we explored our experience of performing TPB under local anaesthesia in an Australian cohort.

METHODS

In this prospective study based at a metropolitan outpatient clinic, patients were provided with TPB under local anaesthesia. We assessed prostate cancer detection rates, complication rates and patient tolerability. Pain tolerability was assess using patient reported pain score on the visual analogue scale. Follow up data was collected at days 7 and 30 post-biopsy via telephone interview.

RESULTS

A total of 48 patients were enrolled in this study between June 2020 and March 2021. Median age was 65.5 years and median PSA was 6.95 ng/mL. Clinically significant prostate cancer was detected in 58% of patients. During the procedure, pain scores were rated the highest during infiltration of local anaesthetic agent with a median score of 5. By the conclusion of the procedure, median pain score was 1. Vast majority of patients (85.4%) would opt for a repeat TPB under local anaesthesia should the need for prostate biopsy arise again. Two of our patients experienced infectious complications, and one experienced urinary retention.

CONCLUSION

Our data is in line with currently available data and confirms that TPB under local anaesthesia can be achieved in a safe and tolerable manner.

Recent Trends in Prostate Biopsy Complication Rates and the Role of Aztreonam in Periprocedural Antimicrobial Prophylaxis—A Nationwide Population-Based Study from Korea

An increase in the rate of complications after prostate biopsy (PB) due to increased antibiotic-resistant bacteria is a global issue. We report the safety of aztreonam as a prophylactic antibiotic in patients undergoing PB. We investigated the complication rates according to several antibiotic regimens, including aztreonam. We hypothesized that PB complications increased following a rise in antibiotic-resistant bacteria. We examined the annual rates of complications among patients in our hospital (clinical cohort) and the Korea Health Insurance Review and Assessment Service (HIRA) cohort. Data regarding complications, hospitalization, emergency room (ER) visits, and febrile urinary tract infections occurring within 2 weeks after PB were recorded. The rate of complications was significantly lower in patients who received oral quinolone and intravenous aztreonam than in those who received oral quinolone. The complication rates did not increase throughout the study period. Additionally, 1754 patients from the HIRA cohort were included. The rates of complications, hospitalizations, and ER visits did not increase among these patients. Oral quinolone combined with intravenous aztreonam reduced the rate of febrile complications compared to quinolone alone and was safe to use after PB. Therefore, we recommend intravenous aztreonam with oral quinolone as a prophylactic antibiotic regimen before PB.

Nanomaterials in the Management of Gram-Negative Bacterial Infections

The exploration of multiplexed bacterial virulence factors is a major problem in the early stages of Escherichia coli infection therapy. Traditional methods for detecting Escherichia coli (E. coli), such as serological experiments, immunoassays, polymerase chain reaction, and isothermal microcalorimetry have some drawbacks. As a result, detecting E. coli in a timely, cost-effective, and sensitive manner is critical for various areas of human safety and health. Intelligent devices based on nanotechnology are paving the way for fast and early detection of E. coli at the point of care. Due to their specific optical, magnetic, and electrical capabilities, nanostructures can play an important role in bacterial sensors. Another one of the applications involved use of nanomaterials in fighting microbial infections, including E. coli mediated infections. Various types of nanomaterials, either used directly as an antibacterial agent such as metallic nanoparticles (NPs) (silver, gold, zinc, etc.), or as a nanocarrier to deliver and target the antibiotic to the E. coli and its infected area. Among different types, polymeric NPs, lipidic nanocarriers, metallic nanocarriers, nanomicelles, nanoemulsion/ nanosuspension, dendrimers, graphene, etc. proved to be effective vehicles to deliver the drug in a controlled fashion at the targeted site with lower off-site drug leakage and side effects.

Increasing incidence and antimicrobial resistance in Escherichia coli bloodstream infections: a multinational population-based cohort study

BACKGROUND

Escherichia coli is an important pathogen in humans and is the most common cause of bacterial bloodstream infections (BSIs). The objectives of our study were to determine factors associated with E. coli BSI incidence rate and third-generation cephalosporin resistance in a multinational population-based cohort.

METHODS

We included all incident E. coli BSIs (2014-2018) from national (Finland) and regional (Australia [Canberra], Sweden [Skaraborg], and Canada [Calgary, Sherbrooke, and western interior]) surveillance. Incidence rates were directly age and sex standardized to the European Union 28-country 2018 population. Multivariable negative binomial and logistic regression models estimated factors significantly associated with E. coli BSI incidence rate and third-generation cephalosporin resistance, respectively. The explanatory variables considered for inclusion in both models were year (2014-2018), region (six areas), age (< 70-years-old and ≥ 70-years-old), and sex (female and male).

RESULTS

We identified 31,889 E. coli BSIs from 40.7 million person-years of surveillance. Overall and third-generation cephalosporin-resistant standardized rates were 87.1 and 6.6 cases/100,000 person-years, respectively, and increased 14.0% and 40.1% over the five-year study. Overall, 7.8% (2483/31889) of E. coli BSIs were third-generation cephalosporin-resistant. Calgary, Canberra, Sherbrooke, and western interior had significantly lower E. coli BSI rates compared to Finland. The significant association between age and E. coli BSI rate varied with sex. Calgary, Canberra, and western interior had significantly greater odds of third-generation cephalosporin-resistant E. coli BSIs compared to Finland. Compared to 2014, the odds of third-generation cephalosporin-resistant E. coli BSIs were significantly increased in 2016, 2017, and 2018. The significant association between age and the odds of having a third-generation cephalosporin-resistant E. coli BSI varied with sex.

CONCLUSIONS

Increases in overall and third-generation cephalosporin-resistant standardized E. coli BSI rates were clinically important. Overall, E. coli BSI incidence rates were 40-104% greater than previous investigations from the same study areas. Region, sex, and age are important variables when analyzing E. coli BSI rates and third-generation cephalosporin resistance in E. coli BSIs. Considering E. coli is the most common cause of BSIs, this increasing burden and evolving third-generation cephalosporin resistance will have an important impact on human health, especially in aging populations.

Temporal Trends in Antimicrobial Resistance of Fecal Escherichia coli from Deer

The changing epidemiologic role of wildlife as reservoirs of antimicrobial-resistant bacteria (ARB) is poorly understood. In this study, we characterize the phenotypic resistance of commensal Escherichia coli from fecal samples of 879 individual white-tailed (Odocoileus virginianus; WTD) over a ten-year period and analyze resistance patterns. Our results show commensal E. coli from WTD had significant linear increases in reduced susceptibility to 5 of 12 antimicrobials, including broad-spectrum cephalosporins and fluoroquinolones, from 2006 to 2016. In addition, the relative frequency distribution of minimal inhibitory concentrations of two additional antimicrobials shifted towards higher values from across the study period. The prevalence of multidrug-resistant commensal E. coli increased over the study period with a prevalence of 0%, 2.2%, and 3.7% in 2006, 2012, and 2016, respectively. WTD may be persistently and increasingly exposed to antibiotics or their residues, ARB, and/or antimicrobial resistance genes via contaminated environments like surface water receiving treated wastewater effluent.

Escherichia coli bloodstream infections in the western interior of British Columbia, Canada: a population-based cohort study

Our population-based study objectives were to describe characteristics and outcomes of Escherichia coli bloodstream infections (BSIs), and to evaluate factors associated with outcomes. We included incident E. coli BSIs from western interior residents (British Columbia, Canada; 04/2010–03/2020). We obtained data including patient demographics, location of onset, infection focus, Charlson comorbidity index (CCI), antimicrobial resistance, 30-day all-cause mortality and length of hospital stay (LOS). Using multivariable logistic regression models fitted with generalised estimating equations, we estimated factors associated with 30-day mortality and long post-infection LOS (>75th percentile). We identified 1080 incident E. coli BSIs in 1009 patients. The crude incidence and 30-day mortality rates were 59.1 BSIs and 6.8 deaths/100 000 person-years, respectively. The 30-day case fatality risk was 11.5%. Compared to community-acquired E. coli BSIs, either healthcare-associated or nosocomial cases had higher odds of 30-day mortality. Older cases, non-urogenital BSI foci and CCI ⩾ 3 had higher odds of 30-day mortality compared to younger cases, urogenital foci and CCI < 3. In patients that survived to discharge, those with extended-spectrum β-lactamase (ESBL)-producing E. coli BSIs, nosocomial BSIs, and CCI ⩾ 3 had higher odds of long post-infection LOS compared to those with non-ESBL-producing, community-acquired and healthcare-associated, and CCI < 3. There is a substantial disease burden from E. coli BSIs.

Surveillance of antimicrobial resistance in low- and middle-income countries: a scattered picture

Data on comprehensive population-based surveillance of antimicrobial resistance is lacking. In low- and middle-income countries, the challenges are high due to weak laboratory capacity, poor health systems governance, lack of health information systems, and limited resources. Developing countries struggle with political and social dilemma, and bear a high health and economic burden of communicable diseases. Available data are fragmented and lack representativeness which limits their use to advice health policy makers and orientate the efficient allocation of funding and financial resources on programs to mitigate resistance. Low-quality data means soaring rates of antimicrobial resistance and the inability to track and map the spread of resistance, detect early outbreaks, and set national health policy to tackle resistance. Here, we review the barriers and limitations of conducting effective antimicrobial resistance surveillance, and we highlight multiple incremental approaches that may offer opportunities to strengthen population-based surveillance if tailored to the context of each country.

Impact of Reappraisal of Fluoroquinolone Minimum Inhibitory Concentration Susceptibility Breakpoints in Gram-Negative Bloodstream Isolates

The Clinical Laboratory Standards Institute lowered the fluoroquinolone minimum inhibitory concentration (MIC) susceptibility breakpoints for Enterobacteriaceae and glucose non-fermenting Gram-negative bacilli in January 2019. This retrospective cohort study describes the impact of this reappraisal on ciprofloxacin susceptibility overall and in patients with risk factors for antimicrobial resistance. Gram-negative bloodstream isolates collected from hospitalized adults at Prisma Health-Midlands hospitals in South Carolina, USA, from January 2010 to December 2014 were included. Matched pairs mean difference (MD) with 95% confidence intervals (CI) were calculated to examine the change in ciprofloxacin susceptibility after MIC breakpoint reappraisal. Susceptibility of Enterobacteriaceae to ciprofloxacin declined by 5.2% (95% CI: −6.6, −3.8; p < 0.001) after reappraisal. The largest impact was demonstrated among Pseudomonas aeruginosa bloodstream isolates (MD −7.8, 95% CI: −14.6, −1.1; p = 0.02) despite more conservative revision in ciprofloxacin MIC breakpoints. Among antimicrobial resistance risk factors, fluoroquinolone exposure within the previous 90 days was associated with the largest change in ciprofloxacin susceptibility (MD −9.3, 95% CI: −16.1, −2.6; p = 0.007). Reappraisal of fluoroquinolone MIC breakpoints has a variable impact on the susceptibility of bloodstream isolates by microbiology and patient population. Healthcare systems should be vigilant to systematically adopt this updated recommendation in order to optimize antimicrobial therapy in patients with bloodstream and other serious infections.

Acute prostatitis after prostate biopsy under ciprofloxacin prophylaxis with or without ornidazole and pre-biopsy enema: analysis of 3.479 prostate biopsy cases

Objectives:

To investigate the characteristics of cases of NIH category I acute prostatitis developed after transrectal prostate biopsy and clarifiy the risk factors and preventive factors.

Materials and Methods:

We retrospectively reviewed the medical records of 3.479 cases of transrectal ultrasound-guided needle biopsies performed with different prophylactic antibiotherapy regimens at two different institutions between January 2011 and February 2016. The patients of Group I have received ciprofl oxacin (n=1.523, 500mg twice daily) and the patients of Group II have received ciprofl oxacin plus ornidazole (n=1.956, 500mg twice daily) and cleansing enema combination as prophylactic antibiotherapy. The incidence, clinical features and other related microbiological and clinical data, were evaluated.

Results:

Mean age was 62.38±7.30 (47-75), and the mean prostate volume was 43.17±15.20 (21-100) mL. Of the 3.479 patients, 39 (1.1%) developed acute prostatitis after the prostate biopsy procedure. Of the 39 cases of acute prostatitis, 28/3.042 occurred after the first biopsy and 11/437 occurred after repeat biopsy (p=0.038). In Group I, 22 of 1.523 (1.4%) patients developed acute prostatitis. In Group II, 17 of 1.959 (0.8%) patients developed acute prostatitis. There was no statistical difference between the two groups according to acute prostatitis rates (X2=2.56, P=0.11). Further, hypertension or DM were not related to the development of acute prostatitis (P=0.76, X2=0.096 and P=0.83, X2=0.046, respectively).

Conclusions:

Repeat biopsy seems to increase the risk of acute prostatitis, while the use of antibiotics effective for anaerobic pathogens seems not to be essential yet.

Empirical fluoroquinolones versus broad-spectrum beta-lactams for Gram-negative bloodstream infections in the absence of antimicrobial resistance risk factors

OBJECTIVES

Increasing antimicrobial resistance rates limit empirical antimicrobial treatment options for Gram-negative bloodstream infections (GN-BSI). However, antimicrobial resistance may be predicted based on patient-specific risk factors using precision medicine concepts. This retrospective, 1:2 matched cohort examined clinical outcomes in hospitalized adults without major risk factors for antimicrobial resistance receiving empirical fluoroquinolones or broad-spectrum beta-lactams (BSBL) for GN-BSI at Prisma Health-Midlands hospitals in Columbia, SC, USA from January 2010 through June 2015.

METHODS

Multivariable logistic regression was used to examine early treatment failure at 72-96 h from GN-BSI. Cox proportional hazards regression was used to examine 28-day mortality and hospital length of stay (HLOS).

RESULTS

Among 74 and 148 patients receiving empirical fluoroquinolones and BSBL for GN-BSI, respectively, median age was 68 years, 159 (72%) were women, and 152 (68%) had a urinary source of infection. Early treatment failure rates were comparable in fluoroquinolone and BSBL groups (27% vs. 30%, respectively, odds ratio 0.82, 95% confidence intervals [CI] 0.43-1.54, P = 0.53), as well as 28-day mortality (8.9% vs. 9.7%, respectively, hazards ratio [HR] 0.74, 95% CI 0.26-1.90, P = 0.54). Median HLOS was 6.1 days in the fluoroquinolone group and 7.1 days in the BSBL group (HR 0.73, 95% CI 0.54-0.99, P = 0.04). Transition from intravenous to oral therapy occurred sooner in the fluoroquinolone group than in the BSBL group (3.0 vs. 4.9 days, P < 0.001).

CONCLUSIONS

In the absence of antimicrobial resistance risk factors, fluoroquinolones provide an additional empirical treatment option to BSBL for GN-BSI. Shorter HLOS in the fluoroquinolone group may be due to earlier transition from intravenous to oral antimicrobial therapy.

Prediction of trimethoprim/sulfamethoxazole resistance in community-onset urinary tract infections

OBJECTIVES

This study aimed to predict trimethoprim/sulfamethoxazole (SXT) resistance in patients with community-onset urinary tract infection (UTI) due to Enterobacteriaceae based on patient-specific risk factors.

METHODS

This was a retrospective case-control study in Prisma Health facilities in central South Carolina, USA, including three community hospitals, affiliated emergency departments and ambulatory clinics, including adult patients with community-onset UTI due to Enterobacteriaceae (1 April 2015 to 29 February 2016). Multivariate logistic regression was used to examine risk factors for SXT resistance.

RESULTS

Among 351 unique patients with community-onset UTI, 71 (20.2%) had SXT-resistant Enterobacteriaceae urinary isolates. Overall, median age was 64 years and 252 (71.8%) were female. A multivariate model identified prior urinary infection/colonisation with SXT-resistant Enterobacteriaceae (OR=8.58, 95% CI 3.92-18.81; P<0.001) and SXT use within past 12 months (OR=2.58, 95% CI 1.13-5.89; P=0.02) as predictors of SXT resistance among urinary isolates. Most patients with UTI (285; 81.2%) had no risk factors for SXT resistance. SXT resistance rates increased from 13% in the absence of risk factors to 31% in patients with prior SXT use, 66% in those with prior urinary infection/colonisation with SXT-resistant Enterobacteriaceae and 73% in the presence of both risk factors.

CONCLUSION

SXT resistance in Enterobacteriaceae urinary isolates may be predicted based on prior urine culture results and SXT use within the previous year. Utilisation of a patient-specific antibiogram may allow empirical SXT use in patients with community-onset UTI in the absence of risk factors for resistance.

Direct Measurement of Performance: A New Era in Antimicrobial Stewardship

For decades, the performance of antimicrobial stewardship programs (ASPs) has been measured by incidence rates of hospital-onset Clostridioides difficile and other infections due to multidrug-resistant bacteria. However, these represent indirect and nonspecific ASP metrics. They are often confounded by factors beyond an ASP’s control, such as changes in diagnostic testing methods or algorithms and the potential of patient-to-patient transmission. Whereas these metrics remain useful for global assessment of healthcare systems, antimicrobial use represents a direct metric that separates the performance of an ASP from other safety and quality teams within an institution. The evolution of electronic medical records and healthcare informatics has made measurements of antimicrobial use a reality. The US Centers for Disease Control and Prevention’s initiative for reporting antimicrobial use and standardized antimicrobial administration ratio in hospitals is highly welcomed. Ultimately, ASPs should be evaluated based on what they do best and what they can control, that is, antimicrobial use within their own institution. This narrative review critically appraises existing stewardship metrics and advocates for adopting antimicrobial use as the primary performance measure. It proposes novel formulas to adjust antimicrobial use based on quality of care and microbiological burden at each institution to allow for meaningful inter-network and inter-facility comparisons.

Antimicrobial resistance prevalence, rates of hospitalization with septicemia and rates of mortality with sepsis in adults in different US states

OBJECTIVES

Rates of hospitalization with sepsis/septicemia and associated mortality in the US have risen significantly during the last two decades. Antibiotic resistance may contribute to the rates of sepsis-related outcomes through lack of clearance of bacterial infections following antibiotic treatment during different stages of infection. However, there is limited information about the relationship between prevalence of resistance to various antibiotics in different bacteria and rates of sepsis-related outcomes.

METHODS

For different age groups of adults (18-49y, 50-64y, 65-74y, 75-84y, 85+y) and combinations of antibiotics/bacteria, we evaluated associations between state-specific prevalence (percentage) of resistant samples for a given combination of antibiotics/bacteria among catheter-associated urinary tract infections (CAUTIs) in the CDC Antibiotic Resistance Patient Safety Atlas data between 2011-2014, and rates of hospitalization with septicemia (ICD-9 codes 038.xx present on the discharge diagnosis) reported to the Healthcare Cost and Utilization Project (HCUP), as well as rates of mortality with sepsis (ICD-10 codes A40-41.xx present on death certificate).

RESULTS

Among the different combinations of antibiotics/bacteria, prevalence of resistance to fluoroquinolones in Escherichia coli had the strongest association with septicemia hospitalization rates for individuals aged over 50y, and with sepsis mortality rates for individuals aged 18-84y. There were several positive correlations between prevalence of resistance for different combinations of antibiotics/bacteria and septicemia hospitalization/sepsis mortality rates in adults.

CONCLUSIONS

These findings, and those from work on the relationship between antibiotic use and sepsis rates, support the association between use of/resistance to certain antibiotics and rates of sepsis-related outcomes, indicating the potential utility of antibiotic replacement.

Oral and intravenous fosfomycin in complicated urinary tract infections

Urinary tract infections are one of the most common health problems and entail a high consumption of health system resources. Due to the increase in global antibiotic resistances in recent years, it is increasingly common to find uropathogens with multiple resistance mechanisms, including quinolone-resistant bacteria, broad-spectrum β-lactamase producers and carbapenemase producers. In this scenario, the role of fosfomycin has gained considerable importance, given its spectrum of activity against multidrug resistant microorganisms (Gram-positive and Gram-negative), becoming an attractive alternative therapy. Regarding the use of fosfomycin in complicated urinary tract infections, there is increasing clinical experience with patients with infections caused by multidrug resistant bacteria, those with recurrent urinary tract infection and special populations such as those with kidney transplants. Randomized comparative studies and series are underway, which will provide greater evidence. Nevertheless, more studies are needed to confirm the enormous potential of fosfomycin in complicated urinary tract infection in the era of multiresistance.

Mortality impact of empirical antimicrobial therapy in ESBL- and AmpC-producing Enterobacteriaceae bacteremia in an Australian tertiary hospital

BACKGROUND

Treatment of ESBL- and AmpC-producing Enterobacteriaceae bacteremia is often complicated by lack of appropriate antibiotics. We aimed to determine the predictors of mortality and impact of empirical antibiotics.

METHODS

A retrospective observational study was performed on consecutive adult cases of ESBL and AmpC bacteremia at the Alfred Hospital from 2014 through April 2018.

RESULTS

Among 110 patients with ESBL (88.2%) and AmpC (14.5%) bacteremia episodes, 96.4% had comorbidities such as hematological malignancy (30%). Approximately 45% were on immunosuppressive drugs, while 69% had recent antibiotic exposure. Over 84% of bacteremias were hospital acquired or healthcare associated. Urinary tract was the main source of infection (40%) with E. coli being the commonest organism (66.4%). The isolates were least resistant to gentamicin (21.8%), which was often appropriately used in empirical therapy. About 34% of patients presented with severe sepsis or shock. The 30-day mortality rate was 20% with no correlation with inappropriate empirical antibiotics (52%). There was no significant mortality difference between carbapenem use in empirical and definitive therapy. Respiratory source [OR 11.77, 95% CI 1.30-106.85; p = 0.03], severe sepsis or shock [OR 5.17, 95% CI 1.37-19.55; p = 0.02] and inappropriate definitive therapy [OR 27.93, 95%CI 3.69-211.35; p = 0.001] were independent predictors for mortality.

CONCLUSION

The choice and appropriateness of empirical therapy were not associated with mortality in ESBL and AmpC bacteremia. Prudent use of carbapenem is reasonable with gentamicin as alternative. Emphasis should be on prompt resuscitation in severe sepsis and early detection of ESBL and AmpC to facilitate appropriate switch to definitive therapy.

A prospective randomized trial of povidone-iodine suppository before transrectal ultrasonography-guided prostate biopsy

OBJECTIVES

To investigate a way to reduce infectious complication after transrectal ultrasonography-guided prostate biopsy (TRUS-Bx), we planned a randomized trial to determine whether the use of the povidone-iodine suppository is effective in preventing infectious complications.

METHODS

This study prospectively assessed 250 patients who underwent TRUS-Bx during December 2014 and May 2016. Clinical questionnaire responses and safety were evaluated. Povidone-iodine suppository after glycerin enema was performed 1 to 2 hours before TRUS-Bx. Both groups received the prophylactic antibiotics (ceftriaxone 2.0 g) 30 to 60 minutes before TRUS-Bx. No antibiotics were prescribed after TRUS-Bx.

RESULTS

The 120 were assigned in the treatment group using povidone-iodine suppository and 130 were assigned in the control group. There was no significant difference of clinicopathologic features including age, prostate-specific antigen and cancer detection rate in both groups (P > .05). No infectious and non-infectious complications were reported in both groups. Povidone-iodine suppository-related side effects were not reported. No significant differences in international prostate symptom score, sexual health inventory for men score, and European Organization for Research and Treatment of Cancer Quality of Life questionnaire scores were found between the 2 groups (P > .05). No changes in each questionnaire scores between before and after TRUS-Bx were observed.

CONCLUSIONS

Despite satisfying the predefined sample size, we could not prove the hypothesis that the use of povidone-iodine suppositories after TRUS-Bx would reduce infectious complications. A large-scale, multicenter, prospective study is needed to fully evaluate the clinical efficacy and safety of povidone-iodine suppository prior to TRUS-Bx.

Bloodstream Infection due to Piperacillin/Tazobactam Non-Susceptible, Cephalosporin-Susceptible Escherichia coli: A Missed Opportunity for De-Escalation of Therapy

An increasing number of reports describing Escherichia coli isolates with piperacillin/tazobactam resistance, despite retained cephalosporin susceptibility, suggest further emergence of this phenotypic resistance pattern. In this report, a patient with metastatic breast cancer presented to medical care after two days of chills, nausea, vomiting, reduced oral intake, and generalized weakness. Blood and urine cultures grew E. coli as identified by rapid diagnostics multiplex PCR and MALDI-TOF, respectively. The patient continued to manifest signs of sepsis with hypotension and tachypnea during the first three days of hospitalization despite empirical antimicrobial therapy with intravenous piperacillin/tazobactam. After in vitro antimicrobial susceptibility testing demonstrated a piperacillin/tazobactam minimal inhibitory concentration (MIC) of 64 and a ceftriaxone MIC of ≤1 mcg/mL, antimicrobial therapy was switched from intravenous piperacillin/tazobactam to ceftriaxone. All symptoms and signs of infection resolved within 48 h of starting ceftriaxone therapy. This report describes the clinical failure of piperacillin/tazobactam in the treatment of a bloodstream infection due to E. coli harboring a phenotypic resistance pattern of isolated piperacillin/tazobactam non-susceptibility. The case demonstrates the role of cephalosporins as potential treatment options and highlights the value of early de-escalation of antimicrobial therapy based on rapid diagnostic testing for microbial identification.

Chemoprophylaxis during transrectal prostate needle biopsy: critical analysis through randomized clinical trial

PURPOSE

To compare the efficacy of three chemoprophylaxis approaches in prevention of post-transrectal biopsy infectious complications (TBICs).

METHODS

Patients were randomly assigned to receive ciprofloxacin 3 days 500 mg B.I.D 3 days starting the night prior to biopsy (standard prophylaxis), augmented prophylaxis using ciprofloxacin and single preprocedure shot of 160 mg gentamicin IM (augmented prophylaxis) and rectal swab culture-based prophylaxis (targeted prophylaxis). Patients were assessed 2 weeks prior to biopsy, at biopsy and 2 weeks after. Primary end point was occurrence of post-TBICs that included simple UTI, febrile UTI or sepsis. Secondary end points were post-biopsy change in the inflammatory markers (TLC, ESR and CRP), unplanned visits, hospitalization and occurrence of fluoroquinolones resistance (FQ-R; bacterial growth on MacConkey agar plate with 10 μg/ml ciprofloxacin) in the fecal carriage of screened men.

RESULTS

Between April/2015 and January/2017, standard, augmented and targeted prophylaxes were given to 163, 166 and 167 patients, respectively. Post-TBICs were reported in 43 (26%), 13 (7.8%) and 34 (20.3%) patients following standard, augmented and targeted prophylaxes protocols, respectively (P = 0.000). Post-TBICs included UTI in 23 (4.6%), febrile UTI in 41 (8.2%) and sepsis in 26 (5.2%) patients. Significantly lower number of post-biopsy positive urine culture was depicted in the augmented group (P = 0.000). The number of biopsy cores was statistically different in the three groups (P = 0.004). On multivariate analysis, augmented prophylaxis had independently lower post-TBICs (OR 0.2, 95% CI 0.1-0.4, P = 0.000) when compared with the other two groups regardless of the number of biopsy cores taken (OR 1.07, 95% CI 0.95-1.17, P = 0.229). Post-biopsy hospitalization was needed in four (2%), one (0.6%) and ten (6%) patients following standard, augmented and targeted prophylaxes, respectively (P = 0.014). However, sepsis-related hospitalization was not statistically different. Post-biopsy changes in the inflammatory markers were significantly less in augmented prophylaxis (P < 0.05). FQ-R was depicted in 139 (83.2%) of the screened men.

CONCLUSION

Augmented prophylaxis with single-dose gentamicin is an effective and practical approach. Targeted prophylaxis might be reserved for cases with contraindication to gentamicin.

Clinical and Molecular Correlates of Escherichia coli Bloodstream Infection from Two Geographically Diverse Centers in Rochester, Minnesota, and Singapore

Escherichia coli bacteremia is caused mainly by sequence type complex 131 (STc131) and two clades within its fluoroquinolone-resistance-associated H30 subclone, H30R1 and H30Rx. We examined clinical and molecular correlates of E. coli bacteremia in two geographically distinct centers. We retrospectively studied 251 unique E. coli bloodstream isolates from 246 patients (48 from the Mayo Clinic, Rochester, MN [MN], and 198 from Tan Tock Seng Hospital, Singapore [SG]), from October 2013 through March 2014. Isolates underwent PCR for phylogroup, STc, bla_CTX-M type, and virulence gene profiles, and medical records were reviewed. Although STc131 accounted for 25 to 27% of all E. coli bacteremia isolates at each site, its extended-spectrum-β-lactamase (ESBL)-associated H30Rx clade was more prominent in SG than in MN (15% versus 4%; P = 0.04). In SG only, patients with STc131 (versus other E. coli STc isolates) were more likely to receive inactive initial antibiotics (odds ratio, 2.8; P = 0.005); this was true specifically for patients with H30Rx (odds ratio, 7.0; P = 0.005). H30Rx comprised 16% of community-onset bacteremia episodes in SG but none in MN. In SG, virulence scores were higher for H30Rx than for H30R1, non-H30 STc131, and non-STc131 isolates (P < 0.02 for all comparisons). At neither site did mortality differ by clonal status. The ESBL-associated H30Rx clade was more prevalent and more often of community onset in SG, where it predicted inactive empirical treatment. The clonal distribution varies geographically and has potentially important clinical implications. Rapid susceptibility testing and clonal diagnostics for H30/H30Rx might facilitate earlier prescribing of active therapy.

Trial Comparing a Combined Regimen of Amikacin and Ciprofloxacin to Ciprofloxacin Alone as Transrectal Prostate Biopsy Prophylaxis in the Era of High Fluoroquinolone-Resistant Rectal Flora

BACKGROUND

To investigate whether addition of amikacin to fluoroquinolone (FQ) antimicrobial prophylaxis reduces infections after transrectal ultrasound-guided prostate biopsy (TRUSPB).

METHODS

A total of 503 patients undergoing rectal swab were divided into three groups. Patients with FQ-sensitive rectal flora (group 1, n = 248) were administered ciprofloxacin before TRUSPB, and patients with FQ-resistant rectal flora were either administered ciprofloxacin (group 2, n = 97) or amikacin and ciprofloxacin (group 3, n = 158) before TRUSPB.

RESULTS

Based on the rectal swab, FQ resistance was 54.9%, and extended-spectrum β-lactamase (ESBL) positivity was 17.2%. The incidence of infectious complication in group 1 was 1.6%. Groups 2 and 3, with FQ-resistant rectal flora, tended to have increased infectious complications (5.2% and 4.4%, respectively) but the difference between those results is not statistically significant. The most common pathogens of infectious complications in patients with FQ-resistant rectal flora were FQ-resistant and ESBL-producing Escherichia coli. E. coli pathogens isolated in Group 3 were amikacin-susceptible species. The operation history and ESBL positivity of rectal flora increased the incidence of infectious complications (odds ratio [OR] = 3.68; P = 0.035 and OR = 4.02; P = 0.008, respectively). DM and antibiotics exposure were risk factors for FQ resistance (OR = 2.19; P = 0.002) and ESBL positivity of rectal flora (OR = 2.96; P = 0.005), respectively.

CONCLUSION

Addition of amikacin to ciprofloxacin prophylaxis could not reduce infectious complications in patients with FQ-resistant rectal flora. Despite the amikacin sensitivity of infectious complications, single-dose amikacin addition to ciprofloxacin prophylaxis has limitations.

Molecular diagnosis of antimicrobial resistance in Escherichia coli

INTRODUCTION

Antimicrobial resistance is a growing global public health threat. The complexities of antimicrobial resistance in gram-negative bacteria such as Escherichia coli pose significant diagnostic and therapeutic challenges. Molecular diagnostics are emerging in this field. Areas covered: The authors review the clinical importance of pathogenic E. coli and discuss the mechanisms of resistance to common antibiotics used to treat these infections. We review the literature on antimicrobial susceptibility testing and discuss the current state of phenotypic as well as molecular methodologies. Clinical vignettes are presented to highlight how molecular diagnostics may be used for patient care. Expert commentary: The future use of molecular diagnostics for detection of antimicrobial resistance will be tailored to the context, whether hospital epidemiology, infection control, antibiotic stewardship, or clinical care. Further clinical research is needed to understand how to best apply molecular diagnostics to these settings.

Development of Institutional Guidelines for Management of Gram-Negative Bloodstream Infections: Incorporating Local Evidence

Background: Appropriate empirical antimicrobial therapy is associated with improved outcomes of patients with Gram-negative bloodstream infections (BSI). Objective: Development of evidence-based institutional management guidelines for empirical antimicrobial therapy of Gram-negative BSI. Methods: Hospitalized adults with Gram-negative BSI in 2011-2012 at Palmetto Health hospitals in Columbia, SC, USA, were identified. Logistic regression was used to examine the association between site of infection acquisition and BSI due to Pseudomonas aeruginosa or chromosomally mediated AmpC-producing Enterobacteriaceae (CAE). Antimicrobial susceptibility rates of bloodstream isolates were stratified by site of acquisition and acute severity of illness. Retained antimicrobial regimens had predefined susceptibility rates ≥90% for noncritically ill and ≥95% for critically ill patients. Results: Among 390 patients, health care-associated (odds ratio [OR]: 3.0, 95% confidence interval [CI]: 1.5-6.3] and hospital-acquired sites of acquisition (OR: 3.7, 95% CI: 1.6-8.4) were identified as risk factors for BSI due to P aeruginosa or CAE, compared with community-acquired BSI (referent). Based on stratified bloodstream antibiogram, ceftriaxone met predefined susceptibility criteria for community-acquired BSI in noncritically ill patients (95%). Cefepime and piperacillin-tazobactam monotherapy achieved predefined susceptibility criteria in noncritically ill (95% both) and critically ill patients with health care-associated and hospital-acquired BSI (96% and 97%, respectively) and critically ill patients with community-acquired BSI (100% both). Conclusions: Incorporation of site of acquisition, local antimicrobial susceptibility rates, and acute severity of illness into institutional guidelines provides objective evidence-based approach for optimizing empirical antimicrobial therapy for Gram-negative BSI. The suggested methodology provides a framework for guideline development in other institutions.

Application of Fluoroquinolone Resistance Score in Management of Complicated Urinary Tract Infections

The fluoroquinolone resistance score (FQRS) predicts the probability of fluoroquinolone resistance with good discrimination. The score has been derived from patients with bloodstream infections caused by Gram-negative bacteria and is based on fluoroquinolone use within the past 6 months, among other clinical and health care exposure criteria. This study aims to examine the utility of the FQRS in patients with complicated urinary tract infections (cUTI) and determine whether extension of prior fluoroquinolone use to 12 months improves model discrimination. Adults with cUTI at Palmetto Health in central South Carolina, USA, from 1 April 2015 through 31 July 2015 were prospectively identified. Multivariate logistic regression was used to examine the association between prior fluoroquinolone use and resistance. Among 238 patients, 54 (23%) had cUTI due to fluoroquinolone-resistant bacteria. Overall, the median age was 66 years, 162 (68%) patients were women, and 137 (58%) patients had cUTI due to Escherichia coli Prior exposure to fluoroquinolones within 3 months (adjusted odds ratio [aOR], 23.4; 95% confidence interval [CI], 8.2 to 76.8; P < 0.001) and within 3 to 12 months (aOR, 13.2; 95% CI, 3.1 to 68.4; P < 0.001) was independently associated with fluoroquinolone resistance compared to no prior use. The area under the receiver operating characteristic curve for the FQRS increased from 0.73 to 0.80 when prior fluoroquinolone use was extended from 6 to 12 months. FQRSs of ≥2 and ≥3 had negative predictive values of 91% and 90%, respectively. The modified FQRS stratifies patients with cUTI on the basis of the predicted probability of fluoroquinolone resistance with very good discrimination. Application of the modified FQRS may improve antimicrobial utilization in patients with acute pyelonephritis.

Identification of a novel sequence type of Escherichia coli as the causative agent of pyelonephritis and bloodstream infection

INTRODUCTION

Globally, extra-intestinal pathogenic Escherichia coli are one of the predominant causative agents of bacteraemia.

CASE PRESENTATION

This case report outlines a presentation of community-acquired pyelonephritis and secondary bloodstream infection in an 81-year-old man. Laboratory investigations revealed that the causative isolate was a multi-drug-resistant E. coli of a novel multi-locus sequence type. This sequence type (ST) was designated ST-458 and was most closely related to the globally prevalent ST-131 lineage.

CONCLUSION

This is the first report of a novel E. coli ST, ST-458, which caused pyelonephritis and bacteraemia.

Differential effect of prior β-lactams and fluoroquinolones on risk of bloodstream infections secondary to Pseudomonas aeruginosa

OBJECTIVE

This retrospective case-control study examines risk factors for bloodstream infections (BSI) due to Pseudomonas aeruginosa (PSA).

METHODS

Hospitalized adults with Gram-negative BSI at Palmetto Health from 2010 to 2015 were identified. Multivariate logistic regression was used to examine PSA BSI risk factors.

RESULTS

Seventy and 910 patients with PSA and Enterobacteriaceae BSI, respectively, were included. Prior use of β-lactams (adjusted odds ratio [aOR] 3.9, 95% confidence intervals [CI]: 2.3-6.9), but not fluoroquinolones (aOR 1.0, 95% CI: 0.4-2.2), was a risk factor for PSA BSI. Immune compromised status (aOR 3.7, 95% CI: 2.0-6.7), respiratory source (aOR 4.4, 95% CI: 2.1-8.9), and prolonged hospitalization (aOR 1.9, 95% CI: 1.1-3.5), were predictors of PSA BSI.

CONCLUSIONS

Determination of class of previously used antibiotics among other clinical variables helps identify patients at risk of PSA BSI and offers opportunities to optimize empirical antimicrobial therapy.

Optimizing safety and accuracy of prostate biopsy

PURPOSE OF REVIEW

The objective of this article is to examine the safety of prostate biopsy and discuss the emerging role of MRI-ultrasound fusion technology in improving diagnostic accuracy.

RECENT FINDINGS

Men undergoing prostate biopsy frequently experience minor complications, including hematospermia, hematuria, and infection. Quinolone-resistant bacteria are a growing concern; thus, transperineal access or modification of antibiotic prophylaxis based on local antibiograms is now used to avoid infectious complications.Multiparametric MRI allows visualization of many prostate cancers, and by fusing MRI with real-time ultrasound, a biopsy needle can be directed by a urologist into suspicious regions of interest. Using this new method, detection of clinically significant prostate cancer has increased and the incidence of falsely negative biopsies has decreased.

SUMMARY

Prostate biopsy is generally a safe procedure, and with attention to local patterns of antibiotic resistance, infectious complications can be minimized. MRI-ultrasound fusion has significantly improved the accuracy of prostate biopsy, allowing tracking and targeting not previously possible.

Effectiveness of oral antibiotics for definitive therapy of Gram-negative bloodstream infections

There is paucity of data evaluating intravenous-to-oral antibiotic switch options for Gram-negative bloodstream infections (BSIs). This retrospective cohort study examined the effectiveness of oral antibiotics for definitive treatment of Gram-negative BSI. Patients with Gram-negative BSI hospitalised for <14 days at Palmetto Health Hospitals in Columbia, SC, from 1 January 2010 through 31 December 2013 and discharged on oral antibiotics were included in this study. The cohort was stratified into three groups based on bioavailability of oral antibiotics prescribed (high, ≥95%; moderate, 75-94%; and low, <75%). Kaplan-Meier analysis and multivariate Cox proportional hazards regression were used to examine treatment failure. Among the 362 patients, high, moderate and low bioavailability oral antibiotics were prescribed to 106, 179 and 77 patients, respectively, for definitive therapy of Gram-negative BSI. Mean patient age was 63 years, 217 (59.9%) were women and 254 (70.2%) had a urinary source of infection. Treatment failure rates were 2%, 12% and 14% in patients receiving oral antibiotics with high, moderate and low bioavailability, respectively (P = 0.02). Risk of treatment failure in the multivariate Cox model was higher in patients receiving antibiotics with moderate [adjusted hazard ratio (aHR) = 5.9, 95% CI 1.6-38.5; P = 0.005] and low bioavailability (aHR = 7.7, 95% CI 1.9-51.5; P = 0.003) compared with those receiving oral antimicrobial agents with high bioavailability. These data demonstrate the effectiveness of oral antibiotics with high bioavailability for definitive therapy of Gram-negative BSI. Risk of treatment failure increases as bioavailability of the oral regimen declines.

Antimicrobials: a global alliance for optimizing their rational use in intra-abdominal infections (AGORA)

Intra-abdominal infections (IAI) are an important cause of morbidity and are frequently associated with poor prognosis, particularly in high-risk patients. The cornerstones in the management of complicated IAIs are timely effective source control with appropriate antimicrobial therapy. Empiric antimicrobial therapy is important in the management of intra-abdominal infections and must be broad enough to cover all likely organisms because inappropriate initial antimicrobial therapy is associated with poor patient outcomes and the development of bacterial resistance. The overuse of antimicrobials is widely accepted as a major driver of some emerging infections (such as C. difficile), the selection of resistant pathogens in individual patients, and for the continued development of antimicrobial resistance globally. The growing emergence of multi-drug resistant organisms and the limited development of new agents available to counteract them have caused an impending crisis with alarming implications, especially with regards to Gram-negative bacteria. An international task force from 79 different countries has joined this project by sharing a document on the rational use of antimicrobials for patients with IAIs. The project has been termed AGORA (Antimicrobials: A Global Alliance for Optimizing their Rational Use in Intra-Abdominal Infections). The authors hope that AGORA, involving many of the world's leading experts, can actively raise awareness in health workers and can improve prescribing behavior in treating IAIs.

Prediction of Fluoroquinolone Resistance in Gram-Negative Bacteria Causing Bloodstream Infections

Increasing rates of fluoroquinolone resistance (FQ-R) have limited empirical treatment options for Gram-negative infections, particularly in patients with severe beta-lactam allergy. This case-control study aims to develop a clinical risk score to predict the probability of FQ-R in Gram-negative bloodstream isolates. Adult patients with Gram-negative bloodstream infections (BSI) hospitalized at Palmetto Health System in Columbia, South Carolina, from 2010 to 2013 were identified. Multivariate logistic regression was used to identify independent risk factors for FQ-R. Point allocation in the fluoroquinolone resistance score (FQRS) was based on regression coefficients. Model discrimination was assessed by the area under receiver operating characteristic curve (AUC). Among 824 patients with Gram-negative BSI, 143 (17%) had BSI due to fluoroquinolone-nonsusceptible Gram-negative bacilli. Independent risk factors for FQ-R and point allocation in FQRS included male sex (adjusted odds ratio [aOR], 1.97; 95% confidence intervals [CI], 1.36 to 2.98; 1 point), diabetes mellitus (aOR, 1.54; 95% CI, 1.03 to 2.28; 1 point), residence at a skilled nursing facility (aOR, 2.28; 95% CI, 1.42 to 3.63; 2 points), outpatient procedure within 30 days (aOR, 3.68; 95% CI, 1.96 to 6.78; 3 points), prior fluoroquinolone use within 90 days (aOR, 7.87; 95% CI, 4.53 to 13.74; 5 points), or prior fluoroquinolone use within 91 to 180 days of BSI (aOR, 2.77; 95% CI, 1.17 to 6.16; 3 points). The AUC for both final logistic regression and FQRS models was 0.73. Patients with an FQRS of 0, 3, 5, or 8 had predicted probabilities of FQ-R of 6%, 22%, 39%, or 69%, respectively. The estimation of patient-specific risk of antimicrobial resistance using FQRS may improve empirical antimicrobial therapy and fluoroquinolone utilization in Gram-negative BSI.

Short-term prophylaxis with ciprofloxacin in extended 16-core prostate biopsy

Objective

To evaluate the safety, efficacy and possible complications of 16-core transrectal prostate biopsies using two doses of ciprofloxacin for prophylaxis of infectious complications.

Materials and Methods

Sixteen-core prostate biopsies were performed on a number of patients with different signs of potential prostate cancer. Complications were assessed both during the procedure and one week later. After the procedure, urine samples were collected for culture. The rate of post-biopsy complications, hospital visits and hospitalizations were also analyzed. Ciprofloxacin (500 mg) was administered two hours before, and eight hours after the procedure.

Results

The overall rate of post-biopsy complications was 87.32%, being 5.4% of those considered major complications due to hemorrhage, or to urinary retention. Eight patients required hospital treatment post-biopsy. Fever occurred in just one patient (0.29%). There was no incidence of orchitis, epididymitis, prostatitis, septicemia, hospitalization, or death. The urine culture showed positive results in five patients (2.15%).

Conclusion

One-day prophylaxis with ciprofloxacin proved to be safe and effective in the prevention of infectious complications following 16-core prostate biopsies.

Group B streptococcal infections in the newborn infant and the potential value of maternal vaccination

Group B Streptococcus (GBS) is a leading cause of neonatal bacterial infections in developed countries. Early-onset disease (EOD) occurs at day 0-6 and late-onset disease occurs at day 7-89. Currently, the prevention of EOD relies upon intrapartum antibiotic prophylaxis (IAP) given to women who are GBS positive at prenatal screening or women with risk factors for EOD. Although successfully implemented, IAP has not fully eradicated EOD, and incidence rates of late-onset disease remain unchanged. Furthermore, antibiotic resistance may result from widespread antibiotic use. New prophylactic strategies are therefore of critical importance. A vaccine active against GBS, administered during pregnancy and combined with targeted IAP, could overcome these problems and reduce the mortality and morbidity associated with invasive diseases.

Population-based epidemiology and microbiology of community-onset bloodstream infections

Bloodstream infection (BSI) is a major cause of infectious disease morbidity and mortality worldwide. While a positive blood culture is mandatory for establishment of the presence of a BSI, there are a number of determinants that must be considered for establishment of this entity. Community-onset BSIs are those that occur in outpatients or are first identified <48 h after admission to hospital, and they may be subclassified further as health care associated, when they occur in patients with significant prior health care exposure, or community associated, in other cases. The most common causes of community-onset BSI include Escherichia coli, Staphylococcus aureus, and Streptococcus pneumoniae. Antimicrobial-resistant organisms, including methicillin-resistant Staphylococcus aureus and extended-spectrum β-lactamase/metallo-β-lactamase/carbapenemase-producing Enterobacteriaceae, have emerged as important etiologies of community-onset BSI.

Antibiotic prophylaxis with intravenous ceftriaxone and fluoroquinolone reduces infectious complications after transrectal ultrasound-guided prostatic biopsy

Purpose

To assess the rates of infectious complications before and after the change of prophylactic antibiotic regimens in prostate needle biopsy.

Materials and Methods

The records of 5,577 patients who underwent prostate needle biopsy at Asan Medical Center between August 2005 and July 2012 were retrospectively reviewed. Group 1 (n=1,743) included patients treated between 2005 and 2009 with fluoroquinolone for 3 days, group 2 (n=2,723) included those treated between 2009 and 2012 with ceftriaxone once before the biopsy and fluoroquinolone before biopsy and continue therapy for 3 days, and group 3 (n=1,111) received the same treatment for more than 7 days after the biopsy. Univariable and multivariable logistic regression models addressed risk factors associated with infectious complication after prostate needle biopsy.

Results

Infectious complication after prostate needle biopsy developed in 18 (group 1), seven (group 2), and two patients (group 3) (p=0.001). In group 1, seven patients with infectious complication had positive blood cultures and harbored fluoroquinolone-resistant Escherichia coli, four had ceftriaxone susceptible isolates, and three had extended spectrum beta-lactamase-positive E. coli. Two patients in group 1 required intensive care because of septic shock. In multivariable analysis, the patients with combination of fluoroquinolone and ceftriaxone had significantly lower infectious complication rate than the fluoroquinolon alone (p=0.003).

Conclusions

Antibiotic prophylaxis with ceftriaxone and fluoroquinolone before prostate needle biopsy decreased the risk of potentially serious infectious complications.

Impact of fluoroquinolone resistance in Gram-negative bloodstream infections on healthcare utilization

There has been a concerning increase in fluoroquinolone resistance among Gram-negative bloodstream isolates. This retrospective cohort study examines the implications of fluoroquinolone resistance on use of healthcare resources in patients with Gram-negative bloodstream infections (BSI). Hospitalized adults with first episodes of community-onset Gram-negative BSI from 2010 to 2012 at Palmetto Health Hospitals in Columbia, SC, USA were identified. Multivariate linear regression was used to examine risk factors for prolonged hospital length of stay (HLOS) in survivors of Gram-negative BSI. Among 474 unique patients, 384 (81%) and 90 (19%) had BSI due to fluoroquinolone-susceptible (FQ-S) and fluoroquinolone non-susceptible (FQ-NS) Gram-negative bacilli, respectively. The FQ-NS bloodstream isolates, particularly Escherichia coli, were more likely than FQ-S isolates to be multi-drug resistant (56% versus 6%, p < 0.001). Compared with patients with BSI due to FQ-S bloodstream isolates, those with FQ-NS isolates were more likely to receive inappropriate empirical antimicrobial therapy (26% versus 3%, p < 0.001), have longer mean HLOS (11.6 versus 9.3 days, p 0.03) and treatment duration with intravenous antibiotics during hospitalization (9.1 versus 7.1 days, p 0.001), and use outpatient intravenous antibiotics at hospital discharge (15% versus 8%, p 0.05). After adjustments in the multivariate model, inappropriate empirical antimicrobial therapy was an independent risk factor for prolonged HLOS in survivors of Gram-negative BSI (parameter estimate 3.65 days, 95% CI 0.43-6.86). Multi-drug resistance among FQ-NS bloodstream isolates limits both empirical and definitive antimicrobial treatment options and poses excessive burdens on the healthcare system.

Routine blood cultures in the management of pyelonephritis in pregnancy for improving outcomes

BACKGROUND

Pyelonephritis is a type of urinary tract infection (UTI) that affects the upper urinary tract and kidneys, and is one of the most common conditions for hospitalisation among pregnant women, aside from delivery. Samples of urine and blood are obtained and used for cultures as part of the diagnosis and management of the condition. Acute pyelonephritis requires hospitalisation with intravenous administration of antimicrobial agents. Several studies have questioned the necessity of obtaining blood cultures in addition to urine cultures, citing cost and questioning whether blood testing is superfluous. Pregnant women with bacteraemia require a change in the initial empirical treatment based on the blood culture. However, these cases are not common, and represent approximately 15% to 20% of cases. It is unclear whether blood cultures are essential for the effective management of the condition.

OBJECTIVES

To assess the effectiveness of routine blood cultures to improve health outcomes in the management of pyelonephritis in pregnant women.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register without language or date restrictions (31 December 2014).

SELECTION CRITERIA

Randomised controlled trials and quasi-randomised trials comparing outcomes among pregnant women with pyelonephritis who received initial management with or without blood cultures. Cluster-randomised trials were eligible for inclusion in this review but none were identified. Clinical trials using a cross-over design were not eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed one trial report for inclusion.

MAIN RESULTS

We identified one trial report but this was excluded. No clinical trials met the inclusion criteria for this review.

AUTHORS' CONCLUSIONS

There are no large-scale randomised controlled trials to assess outcomes in the management of pyelonephritis in pregnancy with or without blood cultures. Randomised controlled trials are needed to evaluate the effectiveness of managing pyelonephritis in pregnant women with or without blood cultures, and to assess any adverse outcomes as well as the cost-effectiveness of excluding blood cultures from treatment.

Prolonged clonal spreading and dynamic changes in antimicrobial resistance of Escherichia coli ST68 among patients who stayed in a respiratory care ward

From 2007 to 2009, we collected a total of 83 bacteraemic isolates of Escherichia coli with reduced susceptibility or resistance to third-generation cephalosporins (TGCs). Isolates were genotyped by PFGE and multilocus sequence typing (MLST). The PFGE patterns revealed two highly correlated clusters (cluster E: nine isolates; cluster G: 22 isolates) associated with this prolonged clonal spreading. Compared with cluster E isolates, cluster G isolates were significantly more likely to harbour aac(6')-Ib-cr (P<0.05), and most of these isolates were isolated during a later year than cluster E isolates (P<0.05). By MLST analysis, 94% of cluster E and G isolates (29/31) were ST68. Although no time or space clustering could be identified by the conventional hospital-acquired infection monitoring system, E. coli cases caused by cluster E and G isolates were significantly associated with having stayed in our hospital's respiratory care ward (P<0.05). Isolates obtained from patients who had stayed in the respiratory care ward had a significantly higher rate of aac(6')-Ib-cr and blaCTX-M-14 positivity, and were more likely to belong to ST68/S68-like (all P<0.05). To our knowledge, this is the first report of prolonged clonal spreading caused by E. coli ST68 associated with a stay in a long-term care facility. Using epidemiological investigations and PFGE and MLST analyses, we have identified long-term clonal spreading caused by E. coli ST68, with extra antimicrobial-resistance genes possibly acquired during the prolonged spreading period.