Impact of NG-Test CTX-M MULTI Immunochromatographic Assay on Antimicrobial Management of Escherichia coli Bloodstream Infections

Rapid detection of extended-spectrum-β-lactamase (ESBL) is of paramount importance to accelerate clinical decision-making, optimize antibiotic treatment, and implement adequate infection control measures. This study was aimed at assessing the impact of direct detection of CTX-M ESBL-producers on antimicrobial management of Escherichia coli bloodstream infections over a 2-year period. This study included all E. coli bloodstream infection (BSI) events that were serially processed through a rapid workflow with communication to the clinicians of direct detection of CTX-M ESBL-producers and conventional culture-based workflow. Antimicrobial management was retrospectively analyzed to assess the contribution of the rapid test result. A total of 199 E. coli BSI events with a report of direct detection of CTX-M ESBL production results were included. Of these, 33.7% (n = 67) and 66.3% (n = 132) were reported as positive and negative CTX-M producers, respectively. Detection of CTX-M positive results induced more antibiotic therapy modifications (mainly towards carbapenem-containing regimens, p < 0.01), and antimicrobial susceptibility testing results of CTX-M ESBL-producing E. coli isolates induced more antibiotic escalations towards carbapenem-containing regimens (p < 0.01). Direct detection of CTX-M ESBL-producing E. coli resulted in a remarkable rate of antibiotic optimizations on the same day of blood culture processing. Observing antibiotic management following the availability of antimicrobial susceptibility testing results, additional early optimizations in escalation could probably have been made if the rapid test data had been used. Detection of CTX-M negative results resulted in few therapeutic changes, which could have probably been higher, integrating epidemiological and clinical data.

Synthesis, biological evaluation, and molecular docking studies of aldotetronic acid-based LpxC inhibitors

In order to develop novel inhibitors of the bacterial deacetylase LpxC bearing a substituent to target the UDP binding site of the enzyme, a series of aldotetronic acid-based hydroxamic acids was accessed in chiral pool syntheses starting from 4,6-O-benzylidene-d-glucose and l-arabinitol. The synthesized hydroxamic acids were tested for LpxC inhibitory activity in vitro, revealing benzyl ether 17a ((2S,3S)-4-(benzyloxy)-N,3-dihydroxy-2-[(4-{[4-(morpholinomethyl)phenyl]ethynyl}benzyl)oxy]butanamide) as the most potent LpxC inhibitor. This compound was additionally tested for antibacterial activity against a panel of clinically relevant Gram-negative bacteria, bacterial uptake, and susceptibility to efflux pumps. Molecular docking studies were performed to rationalize the observed structure-activity relationships.

Colonisation with Extended-Spectrum Cephalosporin-Resistant Enterobacterales and Infection Risk in Surgical Patients: A Systematic Review and Meta-analysis

INTRODUCTION

Limited evidence has been reported for surgical site infections (SSIs) in patients undergoing surgery who are carriers of extended-spectrum cephalosporin-resistant Enterobacterales (ESCR-E). A systematic review and meta-analysis were conducted to evaluate the risk of postoperative infections in adult inpatients colonised with ESCR-E before surgery.

METHODS

The Medline, Embase and Cochrane databases were searched between January 2011 and April 2022, following PRISMA indications. Random effects meta-analysis was used to quantify the association between ESCR-E colonisation and infection.

RESULTS

Among the 467 articles reviewed, 9 observational studies encompassing 7219 adult patients undergoing surgery were included. The ESCR-E colonisation rate was 13.7% (95% CI 7.7-19.7). The most commonly reported surgeries included abdominal surgery (44%) and liver transplantation (LT; 33%). The SSI rate was 23.2% (95% CI 13.2-33.1). Pooled incidence risk was 0.36 (95% CI 0.22-0.50) vs 0.13 (95% CI 0.02-0.24) for any postoperative infection and 0.28 (95% CI 0.18-0.38) vs 0.17 (95% CI 0.07-0.26) for SSIs in ESCR-E carriers vs noncarriers, respectively. In ESCR-E carriers, the ESCR-E infection ratio was 7 times higher than noncarriers. Postoperative infection risk was higher in carriers versus noncarriers following LT. Sources of detected heterogeneity between studies included ESCR-E colonisation and the geographic region of origin.

CONCLUSIONS

Patients colonised with ESCR-E before surgery had increased incidence rates of post-surgical infections and SSIs compared to noncarriers. Our results suggest considering the implementation of pre-surgical screening for detecting ESCR-E colonisation status according to the type of surgery and the local epidemiology.

Antibiotic-Loaded Gold Nanoparticles: A Nano-Arsenal against ESBL Producer-Resistant Pathogens

The advent of new antibiotics has helped clinicians to control severe bacterial infections. Despite this, inappropriate and redundant use of antibiotics, inadequate diagnosis, and smart resistant mechanisms developed by pathogens sometimes lead to the failure of treatment strategies. The genotypic analysis of clinical samples revealed that the rapid spread of extended-spectrum β-lactamases (ESBLs) genes is one of the most common approaches acquired by bacterial pathogens to become resistant. The scenario compelled the researchers to prioritize the design and development of novel and effective therapeutic options. Nanotechnology has emerged as a plausible groundbreaking tool against resistant infectious pathogens. Numerous reports suggested that inorganic nanomaterials, specifically gold nanoparticles (AuNPs), have converted unresponsive antibiotics into potent ones against multi-drug resistant pathogenic strains. Interestingly, after almost two decades of exhaustive preclinical evaluations, AuNPs are gradually progressively moving ahead toward clinical evaluations. However, the mechanistic aspects of the antibacterial action of AuNPs remain an unsolved puzzle for the scientific fraternity. Thus, the review covers state-of-the-art investigations pertaining to the efficacy of AuNPs as a tool to overcome ESBLs acquired resistance, their applicability and toxicity perspectives, and the revelation of the most appropriate proposed mechanism of action. Conclusively, the trend suggested that antibiotic-loaded AuNPs could be developed into a promising interventional strategy to limit and overcome the concerns of antibiotic-resistance.

Systematic Review and Meta-analysis on Extended-Spectrum β-lactamases Producing Klebsiella pneumoniae in Nepal

Objective

This systematic review and meta-analysis aimed to assess the pool estimates of extended-spectrum β-lactamases producing K. pneumoniae (ESBL-KP) and study their drug resistance profile by evaluating the studies from Nepal.

Methods

A literature search was carried out in PubMed, Google Scholar, and NepJOL to screen all articles on ESBL-KP published between 2011 and 2021 from Nepal. This review was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Relevant data were extracted, and R language 4.2.0 software was used for statistical analysis.

Results

The pooled prevalence of K. pneumoniae was 5%, while the pooled prevalence of ESBL and multidrug resistance (MDR) in K. pneumoniae were 23% and 55%, respectively. Imipenem was the drug of choice (in vitro) against ESBL-KP infection.

Conclusion

Our analyses showed a high prevalence of ESBL-KP and their high resistance toward commonly used drugs. This study highlights the need for the development of new antibiotics for the management of ESBL-KP infections.

Clinical data from studies involving novel antibiotics to treat multidrug-resistant Gram-negative bacterial infections

Multidrug-resistant (MDR) Gram-negative bacteria (GNB) are a critical threat to healthcare worldwide, worsening outcomes and increasing mortality among infected patients. Carbapenemase- and extended-spectrum β-lactamase-producing Enterobacterales, as well as carbapenemase-producing Pseudomonas and Acinetobacter spp., are common MDR pathogens. To address this threat, new antibiotics and combinations have been developed. Clinical trial findings support several combinations, notably ceftazidime-avibactam (CZA, a cephalosporin-β-lactamase inhibitor combination) which is effective in treating complicated urinary tract infections (cUTI), complicated intra-abdominal infections and hospital-acquired and ventilator-associated pneumonia caused by GNBs. Other clinically effective combinations include meropenem-vaborbactam (MVB), ceftolozane-tazobactam (C/T) and imipenem- relebactam (I-R). Cefiderocol is a recent siderophore β-lactam antibiotic that is useful against cUTIs caused by carbapenem-resistant Enterobacterales (CRE) and is stable against many β-lactamases. CRE are a genetically heterogeneous group that vary in different world regions and are a substantial cause of infections, among which Klebsiella pneumoniae are the most common. Susceptible CRE infections can be treated with fluoroquinolones, aminoglycosides or fosfomycin, but alternatives include CZA, MVB, I-R, cefiderocol, tigecycline and eravacycline. MDR Acinetobacter baumannii and Pseudomonas aeruginosa are increasingly common pathogens producing a range of different carbapenemases, and infections are challenging to treat, often requiring novel antibiotics or combinations. Currently, no single agent can treat all MDR-GNB infections, but new β-lactam-β-lactamase inhibitor combinations are often effective for different infection sites, and, when used appropriately, have the potential to improve outcomes. This article reviews clinical studies investigating novel β-lactam approaches for treatment of MDR-GNB infections.

New CTX-M Group Conferring β-Lactam Resistance: A Compendium of Phylogenetic Insights from Biochemical, Molecular, and Structural Biology

The production of extended-spectrum β-lactamases (ESBLs) is the main defense mechanism found in Gram negative bacteria. Among all the ESBLs, the CTX-M enzymes appear as the most efficient in terms of dissemination in different epidemiological contexts. CTX-M enzymes exhibit a striking plasticity, with a large number of allelic variants distributed in several sublineages, which can be associated with functional heterogeneity of clinical relevance. This observational analytical study provides an update of this family, currently with more than 200 variants described, from a phylogenetic, molecular, and structural point of view through homology in amino acid sequences. Our data, combined with described literature, provide phylogenetic and structural evidence of a new group. Thus, herein, we propose six groups among CTX-M enzymes: the already stablished CTX-M-1, CTX-M-2, CTX-M-8, CTX-M-9, and CTX-M-25 clusters, as well as CTX-M-151 as the new cluster.

Effectiveness of Fosfomycin for the Treatment of Multidrug-Resistant Escherichia coli Bacteremic Urinary Tract Infections: A Randomized Clinical Trial

IMPORTANCE

The consumption of broad-spectrum drugs has increased as a consequence of the spread of multidrug-resistant (MDR) Escherichia coli. Finding alternatives for these infections is critical, for which some neglected drugs may be an option.

OBJECTIVE

To determine whether fosfomycin is noninferior to ceftriaxone or meropenem in the targeted treatment of bacteremic urinary tract infections (bUTIs) due to MDR E coli.

DESIGN, SETTING, AND PARTICIPANTS

This multicenter, randomized, pragmatic, open clinical trial was conducted at 22 Spanish hospitals from June 2014 to December 2018. Eligible participants were adult patients with bacteremic urinary tract infections due to MDR E coli; 161 of 1578 screened patients were randomized and followed up for 60 days. Data were analyzed in May 2021.

INTERVENTIONS

Patients were randomized 1 to 1 to receive intravenous fosfomycin disodium at 4 g every 6 hours (70 participants) or a comparator (ceftriaxone or meropenem if resistant; 73 participants) with the option to switch to oral fosfomycin trometamol for the fosfomycin group or an active oral drug or parenteral ertapenem for the comparator group after 4 days.

MAIN OUTCOMES AND MEASURES

The primary outcome was clinical and microbiological cure (CMC) 5 to 7 days after finalization of treatment; a noninferiority margin of 7% was considered.

RESULTS

Among 143 patients in the modified intention-to-treat population (median [IQR] age, 72 [62-81] years; 73 [51.0%] women), 48 of 70 patients (68.6%) treated with fosfomycin and 57 of 73 patients (78.1%) treated with comparators reached CMC (risk difference, -9.4 percentage points; 1-sided 95% CI, -21.5 to ∞ percentage points; P = .10). While clinical or microbiological failure occurred among 10 patients (14.3%) treated with fosfomycin and 14 patients (19.7%) treated with comparators (risk difference, -5.4 percentage points; 1-sided 95% CI, -∞ to 4.9; percentage points; P = .19), an increased rate of adverse event-related discontinuations occurred with fosfomycin vs comparators (6 discontinuations [8.5%] vs 0 discontinuations; P = .006). In an exploratory analysis among a subset of 38 patients who underwent rectal colonization studies, patients treated with fosfomycin acquired a new ceftriaxone-resistant or meropenem-resistant gram-negative bacteria at a decreased rate compared with patients treated with comparators (0 of 21 patients vs 4 of 17 patients [23.5%]; 1-sided P = .01).

CONCLUSIONS AND RELEVANCE

This study found that fosfomycin did not demonstrate noninferiority to comparators as targeted treatment of bUTI from MDR E coli; this was due to an increased rate of adverse event-related discontinuations. This finding suggests that fosfomycin may be considered for selected patients with these infections.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02142751.

Direct detection of extended-spectrum-β-lactamase-producers in Enterobacterales from blood cultures: a comparative analysis

Accurate detection of extended-spectrum-β-lactamase (ESBL)-producing Enterobacterales from bloodstream infection (BSI) is of paramount importance for both epidemiological and clinical purposes, especially for optimization of antibiotic stewardship interventions. Three phenotypic methods for the detection of ESBL phenotype in Klebsiella pneumoniae and Escherichia coli BSI were compared over a 4-month period (May-August 2021) in a main University Hospital from Northern Italy. The methods were the biochemical Rapid ESBL NP®, the immunological NG-Test CTX-M MULTI®, and the E-test technique based on ESBL E-test®. One hundred forty-two blood cultures (BCs) positive for K. pneumoniae or E. coli were included. ESBL and carbapenemase phenotype were detected in 26.1% (n = 37) and 16.9% (n = 24), respectively. The Rapid ESBL NP®, NG-Test CTX-M MULTI®, and direct ESBL E-test® positive and negative predictive values with 95% confidence intervals were 1 (0.87-1) and 0.97 (0.92-0.99), 1 (0.87-1) and 0.97 (0.92-0.99), and 1 (0.88-1) and 1 (0.96-1), respectively. The three phenotypic methods evaluated showed good performance in the detection of ESBL phenotype from K. pneumoniae- or E. coli-positive BCs. Rapid ESBL NP® and NG-test CTX-M® offer the important advantage of a turnaround time of 15 to 45 min, and the Rapid ESBL NP test in addition detects any type of ESBL producers.

Extraintestinal Pathogenic Escherichia coli: Virulence Factors and Antibiotic Resistance

The One Health approach emphasizes the importance of antimicrobial resistance (AMR) as a major concern both in public health and in food animal production systems. As a general classification, E. coli can be distinguished based on the ability to cause infection of the gastrointestinal system (IPEC) or outside of it (ExPEC). Among the different pathogens, E. coli are becoming of great importance, and it has been suggested that ExPEC may harbor resistance genes that may be transferred to pathogenic or opportunistic bacteria. ExPEC strains are versatile bacteria that can cause urinary tract, bloodstream, prostate, and other infections at non-intestinal sites. In this context of rapidly increasing multidrug-resistance worldwide and a diminishingly effective antimicrobial arsenal to tackle resistant strains. ExPEC infections are now a serious public health threat worldwide. However, the clinical and economic impact of these infections and their optimal management are challenging, and consequently, there is an increasing awareness of the importance of ExPECs amongst healthcare professionals and the general public alike. This review aims to describe pathotype characteristics of ExPEC to increase our knowledge of these bacteria and, consequently, to increase our chances to control them and reduce the risk for AMR, following a One Health approach.

Extended-spectrum β-lactamases: an update on their characteristics, epidemiology and detection

Extended-spectrum β-lactamase (ESBL)-producing Gram-negative pathogens are a major cause of resistance to expanded-spectrum β-lactam antibiotics. Since their discovery in the early 1980s, they have spread worldwide and an are now endemic in Enterobacterales isolated from both hospital-associated and community-acquired infections. As a result, they are a global public health concern. In the past, TEM- and SHV-type ESBLs were the predominant families of ESBLs. Today CTX-M-type enzymes are the most commonly found ESBL type with the CTX-M-15 variant dominating worldwide, followed in prevalence by CTX-M-14, and CTX-M-27 is emerging in certain parts of the world. The genes encoding ESBLs are often found on plasmids and harboured within transposons or insertion sequences, which has enabled their spread. In addition, the population of ESBL-producing Escherichia coli is dominated globally by a highly virulent and successful clone belonging to ST131. Today, there are many diagnostic tools available to the clinical microbiology laboratory and include both phenotypic and genotypic tests to detect β-lactamases. Unfortunately, when ESBLs are not identified in a timely manner, appropriate antimicrobial therapy is frequently delayed, resulting in poor clinical outcomes. Several analyses of clinical trials have shown mixed results with regards to whether a carbapenem must be used to treat serious infections caused by ESBLs or whether some of the older β-lactam-β-lactamase combinations such as piperacillin/tazobactam are appropriate. Some of the newer combinations such as ceftazidime/avibactam have demonstrated efficacy in patients. ESBL-producing Gram-negative pathogens will continue to be major contributor to antimicrobial resistance worldwide. It is essential that we remain vigilant about identifying them both in patient isolates and through surveillance studies.

Global prevalence and molecular characterization of extended-spectrum β-lactamase producing-Escherichia coli in dogs and cats - A scoping review and meta-analysis

Antimicrobial resistance (AMR) represents a major threat to human and animal health. Part of the AMR dimension is the circulation of extended-spectrum β-lactamases producing-Escherichia coli (ESBL-E. coli), which is now commonly reported among companion animals. However, the global perspective of the prevalence and population structure of ESBL-E. coli circulating in dogs and cats has not been estimated limiting our understanding of their role in the dissemination of ESBL-E. coli. The aim of this study was to compare the prevalence of ESBL-E. coli between dogs and cats and across countries through meta-analysis. We also performed a scoping review to summarize the current knowledge on ESBL genes and E. coli clones circulating among companion animals. A total of 128 studies published in PubMed, Web of Science, and Scopus up to April 2020 were selected and contained information on prevalence and/or molecular characterization of ESBL genes and ESBL-E. coli clones. Our review shows an increase in the number of publications between 2000 and 2019, concentrated mainly in Europe. Prevalence varied across continents, ranging from 0.63% (Oceania) to 16.56% (Africa) in dogs and from 0% (Oceania) to 16.82% (Asia) in cats. Although there were twice as many studies reporting prevalence on dogs (n = 61) than on cats (n = 32), and only 9 studies focused exclusively on cats, our meta-analysis showed no difference in the global prevalence of ESBL-E. coli between dogs (6.87% [95% CI: 4.46-10.45%]) and cats (5.04% [95% CI: 2.42-10.22%]). A considerable diversity of ESBL genes (n = 60) and sequence types (ST) (n = 171) were recovered from companion animals. ESBL-E. coli encoded by CTX-M-15 (67.5%, 77/114) and SHV-12 (21.9%, 25/114), along with resistant strains of ST38 (22.7%, 15/66) and ST131 (50%, 33/66) were widespread and detected in all continents. While presence of ESBL-E. coli is widespread, the drivers influencing the observed ESBL-E. coli prevalence and the clinical relevance in veterinary medicine and public health along with economic impact of ESBL-E. coli infections among companion animals need to be further investigated.

Population Pharmacokinetics of Piperacillin in Non-Critically Ill Patients with Bacteremia Caused by Enterobacteriaceae

This study analyzes the pharmacokinetic variability of piperacillin in non-critically ill patients with Enterobacteriaceae bloodstream infections (EBSI) and explores predicted clinical outcomes and piperacillin-related neurotoxicity under different renal conditions. Hospitalized, non-critically ill patients treated with piperacillin–tazobactam for EBSI were included. Four serum samples per patient were collected and analyzed. A population pharmacokinetic model was developed using the Pmetrics package for R. Monte Carlo simulations of various dosage regimens of 4 g piperacillin, administered q8 h or q12 h by short (0.5 h) or long (4 h) infusion, following the different glomerular filtration rate (GFR) categories used to classify chronic kidney disease (Kidney Disease: Improving Global Outcomes, KDIGO) to determine the probability of target attainment (PTA) using a free drug concentrations above the minimal inhibitory concentration (fT > MIC) of 50% for efficacy and targets for piperacillin-associated neurotoxicity. Twenty-seven patients (102 samples) were included. Extended piperacillin infusions reached a PTA > 90% (50%fT > MIC) within the susceptibility range, although a loading dose did not greatly improve the expected outcome. Long infusions reduced the expected toxicity in patients with severe renal impairment. The study supports the use of extended infusions of piperacillin in non-critically ill patients with EBSI. No benefits of a loading dose were expected in our population. Finally, extended infusions may reduce the risk of toxicity in patients with severe renal impairment.

Antimicrobial Resistance in Enterobacterales and Its Contribution to Sepsis in Sub-saharan Africa

Antibiotic resistant Enterobacterales (formerly Enterobactereaceae) are a growing threat to Sub-Saharan Africa. Genes causing antibiotic resistance are easily spread between the environment and humans and infections due to drug resistant organisms contribute to sepsis mortality via delayed time to appropriate antimicrobial therapy. Additionally, second or third-line antibiotics are often not available or are prohibitively expensive in resource-constrained settings leading to limited treatment options. Lack of access to water and sanitation facilities, unregulated use of antibiotics, and malnutrition are contributors to high rates of antibiotic resistance in the region. Improvements in the monitoring of drug resistant infections and antibiotic stewardship are needed to preserve the efficacy of antibiotics for the future.

Despite Predominance of Uropathogenic/Extraintestinal Pathotypes Among Travel-acquired Extended-spectrum β-Lactamase-producing Escherichia coli, the Most Commonly Associated Clinical Manifestation Is Travelers' Diarrhea

Background

One-third of the 100 million travelers to the tropics annually acquire extended-spectrum β-lactamase (ESBL)–producing Enterobacteriaceae (ESBL-PE), with undefined clinical consequences.

Methods

Symptoms suggesting Enterobacteriaceae infections were recorded prospectively among 430 Finnish travelers, 90 (21%) of whom acquired ESBL-PE abroad. ESBL-PE isolates underwent polymerase chain reaction–based detection of diarrheagenic Escherichia coli (DEC) pathotypes (enteroaggregative E. coli [EAEC], enteropathogenic E. coli [EPEC], enterotoxigenic E. coli [ETEC], enteroinvasive E. coli, and Shiga toxin–producing E. coli), and extraintestinal pathogenic/uropathogenic E. coli (ExPEC/UPEC). Laboratory-confirmed ESBL-PE infections were surveyed 5 years before and after travel.

Results

Among the 90 ESBL-PE carriers, manifestations of Enterobacteriaceae infection included travelers’ diarrhea (TD) (75/90 subjects) and urinary tract infection (UTI) (3/90). The carriers had 96 ESBL-producing E. coli isolates, 51% exhibiting a molecular pathotype: 13 (14%) were DEC (10 EAEC, 2 EPEC, 1 ETEC) (12 associated with TD) and 39 (41%) ExPEC/UPEC (none associated with UTI). Of ESBL-PE, 3 (3%) were ExPEC/UPEC-EAEC hybrids (2 associated with diarrhea, none with UTI). Potential ESBL-PE infections were detected in 15 of 90 subjects (17%). The 10-year medical record survey identified 4 laboratory-confirmed ESBL-PE infections among the 430 travelers, all in subjects who screened ESBL-PE negative after returning home from their index journeys but had traveled abroad before their infection episodes.

Conclusions

Half of all travel-acquired ESBL-producing E. coli strains qualified molecularly as pathogens. Extraintestinal and uropathogenic pathotypes outnumbered enteric pathotypes (41% vs 14%), yet the latter correlated more closely with symptomatic infection (0% vs 92%). Despite more ESBL-PE strains qualifying as ExPEC/UPEC than DEC, travel-acquired ESBL-PE are more often associated with TD than UTI.

Genotypic and phenotypic traits of blaCTX-M-carrying Escherichia coli strains from an UV-C-treated wastewater effluent

Wastewater treatment plants (WWTPs) are relevant sources of antibiotic resistance into aquatic environments. Disinfection of WWTPs' effluents (e.g. by UV-C irradiation) may attenuate this problem, though some clinically relevant bacteria have been shown to survive disinfection. In this study we characterized 25 CTX-M-producing Escherichia coli strains isolated from a WWTP's UV-C-irradiated effluent, aiming to identify putative human health hazards associated with such effluents. Molecular typing indicated that the strains belong to the phylogroups A, B2 and C and clustered into 9 multilocus sequence types (STs), namely B2:ST131 (n = 7), A:ST58 (n = 1), A:ST155 (n = 4), C:ST410 (n = 2), A:ST453 (n = 2), A:ST617 (n = 2), A:ST744 (n = 1), A:ST1284 (n = 3) and a putative novel ST (n = 3). PCR-screening identified 9 of the 20 antibiotic resistance genes investigated [i.e. sul1, sul2, sul3, tet(A), tet(B), bla_OXA-1-like, aacA4, aacA4-cr and qnrS1]. The more prevalent were sul1, sul2 (n = 15 isolates) and tet(A) (n = 14 isolates). Plasmid restriction analysis indicated diverse plasmid content among strains (14 distinct profiles) and mating assays yielded cefotaxime-resistant transconjugants for 8 strains. Two of the transconjugants displayed a multi-drug resistance (MDR) phenotype. All strains were classified as cytotoxic to Vero cells (9 significantly more cytotoxic than the positive control) and 10 of 21 strains were invasive towards this cell line (including all B2:ST131 strains). The 10 strains tested against G. mellonella larvae exhibited a virulent behaviour. Twenty-four and 7 of the 25 strains produced siderophores and haemolysins, respectively. Approximately 66% of the strains formed biofilms. Genome analysis of 6 selected strains identified several virulence genes encoding toxins, siderophores, and colonizing, adhesion and invasion factors. Freshwater microcosms assays showed that after 28 days of incubation 3 out of 6 strains were still detected by cultivation and 4 strains by qPCR. Resistance phenotypes of these strains remained unaltered. Overall, we confirmed WWTP's UV-C-treated outflow as a source of MDR and/or virulent E. coli strains, some probably capable of persisting in freshwater, and that carry conjugative antibiotic resistance plasmids. Hence, disinfected wastewater may still represent a risk for human health. More detailed evaluation of strains isolated from wastewater effluents is urgent, to design treatments that can mitigate the release of such bacteria.

The Continuing Plague of Extended-Spectrum β-Lactamase Producing Enterbacterales Infections: An Update

Antimicrobial resistance is a common iatrogenic complication of modern life and medical care. One of the most demonstrative examples is the exponential increase in the incidence of extended-spectrum β-lactamases (ESBLs) production among Enterobacteriaceae, that is, the most common human pathogens outside of the hospital setting. Infections resulting from ESBL-producing bacteria are associated with devastating outcomes, now affecting even previously healthy individuals. This poses an enormous burden and threat to public health. This article aims to narrate the evolving epidemiology of ESBL infections and highlights current challenges in terms of management and prevention of these common infections.

Sitafloxacin has a potent activity for eradication of extended spectrum β-lactamase-producing fluoroquinolone-resistant Escherichia coli forming intracellular bacterial communities in uroepithelial cells

INTRODUCTION

Eradication of asymptomatic bacteriuria (ASB) before urological procedures is important to reduce the risk for infectious complications after surgery. However, the appropriate regimen for antimicrobial treatment has not been fully determined. We experienced continuous (over 10 months) isolation of extended spectrum β-lactamase (ESBL)-producing fluoroquinolone-resistant Escherichia coli from urine of an asymptomatic patient. The four isolates obtained (SMESC1 to 4) were international high-risk clones of O25b:H4-ST131-H30R, and originated from one strain, as revealed by the whole genome sequences. Although the patient received meropenem (MEPM) and fosfomycin (FOM), to which the strains were susceptible before the urological procedures, they could not be eradicated.

METHODS

To explore the reason for the continuous isolation even after MEPM and FOM administration, antimicrobial killing of adherent and/or intracellular bacterial communities (IBC) formed by coculture of the E. coli cells and T24 bladder epithelial cells were examined.

RESULTS

FOM and levofloxacin did not decrease viable E. coli cells compared with gentamicin. MEPM partly decreased them, and sitafloxacin (STFX) decreased them most potently. These observations indicate that E. coli can survive in the urinary tract under antimicrobial administration, and some antimicrobials such as FOM and MEPM cannot eradicate E. coli in uroepithelial cells. Adhesion on urinary epithelial cells and/or IBC formation might result in continuous isolation from the urinary tract and recurrence of ASB and urinary tract infections.

CONCLUSIONS

The present study suggests that STFX is a promising optional agent for the eradication of ESBL-producing fluoroquinolone-resistant E. coli in the urinary tract before urological procedures.

Long-term impact of an educational antimicrobial stewardship programme in primary care on infections caused by extended-spectrum β-lactamase-producing Escherichia coli in the community: an interrupted time-series analysis

BACKGROUND

There is little evidence on the ecological effect and sustainability of antimicrobial stewardship programmes (ASPs) in primary-care settings. We aimed to determine whether a multimodal, educational ASP would be sustainable in the long-term and reduce the incidence of infections caused by extended-spectrum β-lactamase-producing Escherichia coli in the community by optimising antibiotic use.

METHODS

We did this quasi-experimental intervention study in 214 primary health centres of four primary health-care districts in Andalusia, Spain. Local multidisciplinary teams, comprised of general practitioners, paediatricians, primary-care pharmacists, and epidemiologists, were created in each district and implemented a multimodal, education-based ASP. The core activity of the programme consisted of regular one-to-one educational interviews between a reference interviewing physician and prescribing physicians from each centre on the appropriateness of their most recent (same or preceding day) antibiotic prescriptions based on a structured questionnaire. Appropriate prescribing was defined as compliance of all checklist items with the reference guidelines. An average of five educational interviews were scheduled per prescriber per study year. We did an interrupted time-series analysis to assess the effect of the intervention on quarterly antibiotic use (prescription and collection by the patient) and quality of prescriptions (as defined daily doses per 1000 inhabitants per day) and incidence per 1000 inhabitants of E coli producing extended-spectrum β-lactamase (ESBL) isolated from urine samples.

FINDINGS

The study was done between January, 2012, and December, 2017, in a pre-intervention period of 2012-13 and an intervention period of 2014-17. Throughout the study period, there were 1387 physicians (1116 general practicioners and 271 paediatricians) in the included health centres serving a mean population of 1 937 512 people (299 331 children and 1 638 181 adults). 24 150 educational interviews were done over the 4 years. Inappropriate antibiotic prescribing was identified in 1794 (36·5%) of 4917 educational interviews in 2014 compared with 1793 (26·9%) of 6665 in 2017 (p<0·0001). The intervention was associated with a sustained reduction in the use of ciprofloxacin (relative effect -15·9%, 95% CI -23·9 to -8·0) and cephalosporins (-22·6%, -35·9 to -9·2), and a sustained increase in the use of amoxicillin (22·2%, 6·4 to 38·0) and fosfomycin trometamol (6·1%, 2·6 to 9·6). The incidence density of ESBL-producing E coli decreased by -0·028 cases per 1000 inhabitants (95% CI -0·034 to -0·021) after the start of the programme, reversing the pre-intervention increase and leading to a relative reduction of -65·6% (-68·2 to -63·0) 4 years later.

INTERPRETATION

Our data suggest that implementation of a multimodal ASP in primary care that is based on individual educational interviews improves the use of antibiotics and results in a sustained significant reduction of infections by ESBL-producing E coli in the community. This information should encourage the implementation of ASPs in primary care.

FUNDING

Instituto de Salud Carlos III, Spanish Government (PI14/01523).

Clinical epidemiology and outcomes of biliary tract infections caused by Klebsiella pneumoniae

Background

Biliary tract infection (BTI) is a common cause of bacteremia, and is associated with high morbidity and mortality. The clinical epidemiology and outcomes of BTI caused by Klebsiella pneumoniae (KP) have not been well investigated.

Methods

This was a retrospective study performed at a university teaching hospital in China from May 2012 to June 2017 that analyzed data for 119 patients with BTI caused by KP. We identified KP from bile cultures obtained before endoscopic or surgical treatment. Patients' demographic characteristics and clinical outcomes were also recorded.

Results

Forty-seven KP strains (39.5%) were positive for the extended spectrum beta-lactamase (ESBL) phenotype. The ESBL-positive group had a higher rate of stay in ICU [12.8% vs. 1.4% (ESBL-negative group); P=0.015] and a significantly longer hospital stay (30.79±31.512 vs. 20.06±23.945 days, respectively; P=0.037). There were no significant differences for 30-day mortality between the two groups; 112 (94.1%) patients survived and 7 (5.9%) died within 30-days of onset. Univariate analysis showed that nonsurvivors were significantly more likely to be older (66.46±22.34 vs. 46±14.84 years, respectively; P=0.001), and have hypoproteinemia (5/7, 71.4% vs. 21/112, 18.8%; P=0.006), immunosuppression (3/7, 42.9% vs. 4/112, 3.6%; P=0.004), solid tumors (5/7, 71.4% vs. 20/112, 17.9%; P=0.004), bloodstream infections (6/7, 85.7% vs. 22/112, 19.6%; P=0.001), and lower surgery rates (1/7, 14.3% vs. 66/112, 58.9%; P=0.042) compared with survivors, respectively. However, we found no significant independent risk factor for mortality. The malignant biliary obstruction group was significantly more likely to have chronic liver disease (P=0.035) than the benign biliary obstruction group, and mortality was higher for the malignant biliary obstruction group (5/25, 20% vs. 2/94, 2.1%, respectively; P=0.05). The malignant biliary group also had higher alkaline phosphatase, and direct and total bilirubin direct levels. Multivariate analysis showed that chronic liver disease was an independent risk factor in patients with malignant biliary disease [odds ratio (OR), 2.431; 95% confidence interval, 1.834-4.031; P=0.001].

Conclusions

Patients with BTI caused by KP were more likely to have the ESBL phenotype, and antibiotic resistance was not associated with overall survival. Patients with malignant biliary obstruction had higher mortality, and chronic liver disease was an independent risk factor.

Comparative Activities of Ceftazidime-Avibactam and Ceftolozane-Tazobactam against Enterobacteriaceae Isolates Producing Extended-Spectrum β-Lactamases from U.S. Hospitals

The activities of ceftazidime-avibactam, ceftolozane-tazobactam, and comparators were evaluated for 733 isolates displaying resistance to broad-spectrum cephalosporins and carrying extended-spectrum β-lactamase (ESBL) genes detected by whole-genome sequencing analysis. Isolates were collected during 2017 in U.S. hospitals. The ESBL producers were 486 Escherichia coli, 190 Klebsiella pneumoniae, and 42 Enterobacter cloacae isolates and isolates from 3 other species. The most common groups of ESBL-encoding genes were bla _CTX-M-15-like (n = 491 isolates) and bla _CTX-M-15 alone (n = 168) or plus bla _OXA-1 (n = 260), followed by bla _CTX-M-14-like (n = 162), which included bla _CTX-M-27 and bla _CTX-M-14 (104 and 51 isolates, respectively), and bla _SHV-12 and bla _SHV-7 (48 and 22 isolates, respectively). ESBL producers carried other β-lactamases, including 1 E. cloacae harboring bla _KPC-3 All ESBL-producing isolates were susceptible to ceftazidime-avibactam, and 90.2/83.9% (CLSI/EUCAST breakpoints) were susceptible to ceftolozane-tazobactam. Tigecycline (98.1/95.8% susceptible) and colistin (99.2%) were comparators that displayed the greatest activity against these isolates. Ceftolozane-tazobactam inhibited 91.4/83.9% of isolates carrying bla _CTX-M-15-like and 97.5/95.1% of isolates carrying bla _CTX-M-14-like, and its activity was more limited against the 91 isolates carrying bla _SHV (66.7/61.1% susceptible). Ceftolozane-tazobactam inhibited 95.5% of the E. coli isolates but only 83.0%, 64.3%, and 80.0% of K. pneumoniae, E. cloacae, and other species harboring ESBL-encoding genes (CLSI breakpoints), respectively. Outer membrane protein sequences for ceftolozane-tazobactam-nonsusceptible isolates did not exhibit significant differences compared to those in genetically related ceftolozane-tazobactam-susceptible isolates. Ceftazidime-avibactam was more active than other agents tested, including ceftolozane-tazobactam, and the activity of this combination was stable regardless of species or ESBL gene carried.

Risk factors for extended-spectrum beta-lactamase-producing Enterobacteriaceae infection causing septic shock in cancer patients with chemotherapy-induced febrile neutropenia

Patients with chemotherapy-induced febrile neutropenia (FN) are vulnerable to extended-spectrum b-lactamase-producing Enterobacteriaceae (ESBL-PE) infection. Early identification of patients suspected to have ESBL-PE infection for empirical carbapenem administration is crucial; nevertheless, risk factors for ESBL-PE causing septic shock remain unclear. We identify factors to predict ESBL-PE in septic shock patients with chemotherapy-induced FN. In this observational, prospectively collected registry-based study, consecutive adult chemotherapy-induced FN patients with septic shock who were admitted to the emergency department between June 2012 and June 2018 were enrolled. Clinical and laboratory data extracted from the septic shock registry were assessed to identify risk factors for ESBL-PE. Of 179 chemotherapy-induced FN septic shock patients, ESBL-PE is isolated in 23 (12.8%). ESBL-PE infection is frequently seen in patients with hepatobiliary cancer (17.4% vs. 4.5%, P = 0.037), leukemia (13.0% vs. 2.6%, P = 0.046), and those with profound neutropenia (defined as absolute neutrophil count < 100) (73.9% vs. 43.6%, P = 0.007) in contrast to those with lung cancer (0% vs. 14.7%, P = 0.048) and other solid cancer (0% vs. 19.2%, P = 0.016). Multivariate logistic regression reveals that profound neutropenia (adjusted OR 3.67; 95% CI 1.372-9.799; P = 0.010) is an independent risk factor for ESBL-PE infection after adjusting age, the presence of solid tumor, and the parameters of sepsis severity scores. ESBL-PE is rare (12.9%) in chemotherapy-induced FN patients with septic shock. Early empirical carbapenem therapy might be considered in chemotherapy-induced FN patients with profound neutropenia.

Trend in Antibiotic Resistance of Extended-Spectrum Beta-Lactamase-Producing Escherichia Coli and Klebsiella Pneumoniae Bloodstream Infections

Objectives:

Extended-spectrum beta-lactamases (ESBLs) have been detected more frequently in members of the Enterobacteriaceae family, particularly Escherichia coli and Klebsiella pneumoniae. Infections caused by ESBL-producing bacteria are often resistant to treatment with various antibiotic classes and accompanied by increased complication risks, mortality, and costs. In this study, blood culture results were analyzed to determine the change in the ESBL production rate and antibiotic susceptibilities in E. coli and K. pneumoniae isolates over a period of 3 years.

Methods:

The results of blood cultures sent to our laboratory between February 2014 and August 2016 were examined retrospectively. Repeat isolates from the same patient were not included when antibiotic susceptibility rates and clinical distributions were calculated. BD Bactec FX automated blood culture system (Becton Dickinson, Sparks, MD, USA) was used to examine the blood cultures. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (Bruker Daltonics, Bremen, Germany) was used to identify microorganisms. For antibiotic susceptibility tests (AST) and ESBL detection Kirby Bauer disk diffusion method or Phoenix automated system (Becton Dickinson, Sparks, MA, USA) was used. When the AST results were evaluated, Clinical and Laboratory Standards Institute breakpoints were used for 2014 and 2015, and European Committee on Antimicrobial Susceptibility Testing breakpoints were used for 2016.

Results:

During the 3-year period, 224 (35%) of 632 E. coli and 137 (31%) of 439 K. pneumoniae isolates were determined to be ES BL-producers. The ESBL-positive isolate percentage for E. coli and K. pneumoniae for 2014, 2015, and 2016 was 23%, 36%, 48% and 23%, 32%, 37%, respectively. The increase in ESBL was statistically significant for both E. coli (p<0.001) and K. pneumoniae (p=0.011). ESBL-positive E. coli and K. pneumoniae strains were most sensitive to carbapenem-class antibiotics, amikacin, and colistin. While there was no meropenem-resistant strain, 5 (3.3%) ertapenem-resistant and 1 (0.7%) imipenem-resistant ESBL E. coli strains were detected. The ESBL K. pneumoniae strain resistance rate to ertapenem, imipenem, and meropenem was 12%, 11.2%, and 11.1%, respectively. The resistance rates of K. pneumonia strains to ertapenem, imipenem, meropenem, and piperacillin-tazobactam increased significantly over the study period (p<0.001).

Conclusion:

Monitoring ESBL rates and the antibiotic susceptibility of E. coli and K. pneumoniae strains of bloodstream infections is of the utmost importance in guiding empiric antibiotic therapies and patient management.

Variations in the Occurrence of Resistance Phenotypes and Carbapenemase Genes Among Enterobacteriaceae Isolates in 20 Years of the SENTRY Antimicrobial Surveillance Program

Background

A total of 178 825 Enterobacteriaceae isolates collected in 199 hospitals from 42 countries worldwide over 20 years (1997 to 2016) of the SENTRY Program were susceptibility tested by reference broth microdilution methods.

Methods

Trends in percentages over time were analyzed by the χ² test. Results were reported as the percentage difference between the first (1997–2000) and the last (2013–2016) time period.

Results

Enterobacteriaceae exhibiting resistance to cephalosporins (extended-spectrum β-lactamase [ESBL] phenotype) and carbapenem resistance (CRE) significantly increased (P < 0.05; χ² test) from 10.3% to 24.0% and 0.6% to 2.9%, respectively. Similar trends were noted for all regions and infection sources. Klebsiella pneumoniae mainly drove the CRE increase. Multidrug-resistance (MDR) rates significantly increased from 7.3% to 15.3% overall, with important trends in all regions and infection sources. Significant increases were noted for MDR K. pneumoniae and Escherichia coli, polymyxin-resistant K. pneumoniae (2.0% to 5.5% overall), and aminoglycoside-resistant E. coli (7.0% to 18.0%) and K. pneumoniae (18.1% to 26.9%) over time in North America and Latin America. Carbapenemase-encoding genes were screened after 2007, and the occurrence of these genes was compared for 2007–2009 and 2014–2016. Among 1298 CRE isolates from the 2 study periods, bla_KPC was detected among 186 (49.7%) and 501 (54.2%) isolates in 2007–2009 and 2014–2016, respectively. Metallo-β-lactamase genes were detected among 4.3% of the isolates from 2007 to 2009 and 12.7% of the isolates from 2014 to 2016, mainly due to the dissemination of isolates carrying bla_NDM. Genes encoding IMP and VIM enzymes were observed in 1.9% and 2.4% (7 and 9 isolates) of the isolates from 2007 to 2009 and 0.4% and 1.9% of the isolates from 2014 to 2016. OXA-48 and variants increased from 4.3% in 2007–2009 to 12.6% in 2014–2016 (mainly in Europe).

Conclusions

A change in the epidemiology of carbapenemases and important increases in ESBL, CRE, MDR, and other resistant phenotypes among virtually all geographic regions and infection sources were noted in the 20 years of surveillance, highlighting the impact of antimicrobial resistance and the importance of its continuous monitoring.

Prevalence of extended-spectrum β-lactamase-producing Klebsiella pneumoniae: First systematic review and meta-analysis from Iran

OBJECTIVES

Extended-spectrum β-lactamase-producing Klebsiella pneumoniae (ESBL-KP) have emerged as an important pathogen causing severe infections worldwide. Infections due to ESBL-KP are associated with high morbidity and mortality, especially in developing countries such as Iran. The aim of this study was to assess the pooled prevalence of ESBL-KP with different gene variants in Iran.

METHODS

A literature search of Medline (via PubMed), Embase, Web of Science and Iranian Database was performed. A meta-analysis was conducted using Comprehensive Meta-Analysis Software (version 2.2, Biostat). A fixed- or random-effects model was used based on the heterogeneity test. Publication bias was determined using Begg's rank correlation and Egger's weighted regression methods.

RESULTS

Among 783 articles identified, 43 studies met the eligibility criteria. The pooled prevalence of ESBL-KP was 43.5% (95% CI 39.3-47.9%) among clinical K. pneumoniae isolates. Among genes encoding ESBLs during 2000-2009, SHV, CTX-M and TEM were found with prevalences of 23.3%, 15.2% and 12.3%, respectively, whilst the prevalences of SHV, CTX-M, TEM and VEB were 24%, 28.1%, 25.2% and 8.3%, respectively, during the period 2010-2018.

CONCLUSION

The prevalence of ESBL-KP has increased steadily in recent years among clinical K. pneumoniae isolates in Iran. Thus, initial identification of ESBL-KP according to Clinical and Laboratory Standards Institute (CLSI) guidelines, proper molecular approaches, and implementation of antimicrobial stewardship programmes in Iranian hospitals together with comprehensive infection control measures are urgently needed to control the dissemination of these strains.

Antibacterial Efficacy of Commercially Available Essential Oils Tested Against Drug-Resistant Gram-Positive Pathogens

The potential antibacterial activity of basil (Ocimum basilicum), chamomile (Matricaria chamomilla), origanum (Thymus capitatus), tea tree (Melaleuca alternifolia) and thyme (Thymus vulgaris) essential oils, was investigated against 29 Gram-positive bacterial strains isolated from wastewater treatment plants, clinical samples (n = 25) and American Type Culture Collection (ATCC) reference strains (n = 4). Wild bacterial strains included methicillin-resistant Staphylococcus aureus (n = 16) and vancomycin-resistant Enterococcus spp. (n = 9). The antimicrobial activity of the selected oils was studied using the broth macrodilution method. The Minimal Inhibitory Concentration (MIC) values for S. aureus ranged from 0.06 to 0.5% (v/v) for origanum oil, 0.06 to 1% (v/v) for thyme oil, 0.12 to 1% (v/v) for tea tree oil, 0.25 to 4% (v/v) for basil oil and 2 to >4% (v/v) for chamomile oil. For enterococci the MIC values were significantly higher ranging from 0.25 to 1% (v/v), 0.5 to 2% (v/v), 1 to 4% (v/v), 4 to >4% (v/v) and >4% (v/v) for the above-mentioned oils, respectively. The main compounds of the tested essential oils were: estragole (Ocimum basilicum), bisabolol and trans-b-farnesene (Matricaria chamomilla), carvacrol and thymol (Thymus capitatus), terpinen-4-ol and p-cymene (Melaleuca alternifolia), thymol, linalool, and p-cymene (Thymus vulgaris). Origanum essential oil yielded the best antimicrobial results followed by thyme, tea tree, and basil oil, while chamomile oil exhibited weak antibacterial properties.

Vagino-rectal colonization and maternal-neonatal transmission of Enterobacteriaceae producing extended-spectrum β-lactamases or carbapenemases: a cross-sectional study

This study sought to determine the prevalence and risk factors for colonization with extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E) and carbapenemase-producing Enterobacteriaceae (CPE) in 815 mothers and 800 newborns using a cross-sectional design; 59 women and 13 neonates were colonized by ESBL-E (prevalence (95% confidence interval): 6.7% (5.2-8.7) and 1.6 (0.7-2.5), respectively). No CPE were found. The most frequent ESBL-E were CTX-M-14 and SHV-12. Vertical transmission occurred in 14% of colonized mothers. The risk factors for colonization were, in mothers: complications in previous pregnancies, more than one urinary tract infection, non-Caucasian ethnicity, and frequently having the main meal outside home; in newborns: colonized mother and vaginal delivery.

Incidence and Risk Factors for Acquisition of Extended-Spectrum β-Lactamase-Producing Enterobacteriaceae in Newborns in Seville, Spain: A Prospective Cohort Study

BACKGROUND

ESBL-producing Enterobacteriaceae (ESBL-E) are an emerging cause of infections in children. Data are scarce on incidence rates and risk factors for acquisition of colonisation with ESBL-E.

METHODS

A total of 46 and 50 newborns from colonised and non-colonised mothers, respectively, were followed during one year after birth. Rectal swabs were performed every 3 months to detect ESBL-E; bla_ESBL were characterised and isolates were typed for comparison. Multivariate analysis for risk factors was performed using Cox regression.

RESULTS

Incidence density of any new acquisition and of first acquisition of ESBL-E was 2.7 and 1.9 episodes per 100 children-month, respectively, among children whose mothers were colonised, and 1.2 and 1.3, respectively, among children whose mothers were not. The weighted average prevalence of colonisation rates during the first year were 15.9% and 8%, respectively. No infections due to ESBL-E were detected. Living with pets at home, breastfeeding, sterilisation of feeding bottles and out-of-home childcare were protective for ESBL-E acquisition; having a colonised mother increased the risk. The most frequent ESBL types were CTX-M-14 and CTX-M-1. In 5/19 (26.3%) children with acquisition of new clones, the acquired ESBL-E was shared with their mothers.

CONCLUSIONS

Acquisition of ESBL-E colonisation is not rare during the first year of life. Breastfeeding and out-of-home childcare were protective for acquisition, and colonised mothers were associated with increased risk. However, the same clone was shared by mother and child in only a subset of acquisition episodes.

Predictors of outcome in patients with severe sepsis or septic shock due to extended-spectrum β-lactamase-producing Enterobacteriaceae

PURPOSE

There are few data in the literature regarding sepsis or septic shock due to extended-spectrum β-lactamases (ESBL)-producing Enterobacteriaceae (E). The aim of this study was to assess predictors of outcome in septic patients with bloodstream infection (BSI) caused by ESBL-E.

METHODS

Patients with severe sepsis or septic shock and BSI due to ESBL-E were selected from the INCREMENT database. The primary endpoint of the study was the evaluation of predictors of outcome after 30 days from development of severe sepsis or septic shock due to ESBL-E infection. Three cohorts were created for analysis: global, empirical-therapy and targeted-therapy cohorts.

RESULTS

367 septic patients were analysed. Overall mortality was 43.9% at 30 days. Escherichia coli (62.4%) and Klebsiella pneumoniae (27.2%) were the most frequent isolates. β-lactam/β-lactamase inhibitor (BLBLI) combinations were the most empirically used drug (43.6%), followed by carbapenems (29.4%). Empirical therapy was active in vitro in 249 (67.8%) patients, and escalation of antibiotic therapy was reported in 287 (78.2%) patients. Cox regression analysis showed that age, Charlson Comorbidity Index, McCabe classification, Pitt bacteremia score, abdominal source of infection and escalation of antibiotic therapy were independently associated with 30-day mortality. No differences in survival were reported in patients treated with BLBLI combinations or carbapenems in empirical or definitive therapy.

CONCLUSIONS

BSI due to ESBL-E in patients who developed severe sepsis or septic shock was associated with high 30-day mortality. Comorbidities, severity scores, source of infection and antibiotic therapy escalation were important determinants of unfavorable outcome.

Treatment of Infections Caused by Extended-Spectrum-Beta-Lactamase-, AmpC-, and Carbapenemase-Producing Enterobacteriaceae

Therapy of invasive infections due to multidrug-resistant Enterobacteriaceae (MDR-E) is challenging, and some of the few active drugs are not available in many countries. For extended-spectrum β-lactamase and AmpC producers, carbapenems are the drugs of choice, but alternatives are needed because the rate of carbapenem resistance is rising. Potential active drugs include classic and newer β-lactam-β-lactamase inhibitor combinations, cephamycins, temocillin, aminoglycosides, tigecycline, fosfomycin, and, rarely, fluoroquinolones or trimethoprim-sulfamethoxazole. These drugs might be considered in some specific situations. AmpC producers are resistant to cephamycins, but cefepime is an option. In the case of carbapenemase-producing Enterobacteriaceae (CPE), only some "second-line" drugs, such as polymyxins, tigecycline, aminoglycosides, and fosfomycin, may be active; double carbapenems can also be considered in specific situations. Combination therapy is associated with better outcomes for high-risk patients, such as those in septic shock or with pneumonia. Ceftazidime-avibactam was recently approved and is active against KPC and OXA-48 producers; the available experience is scarce but promising, although development of resistance is a concern. New drugs active against some CPE isolates are in different stages of development, including meropenem-vaborbactam, imipenem-relebactam, plazomicin, cefiderocol, eravacycline, and aztreonam-avibactam. Overall, therapy of MDR-E infection must be individualized according to the susceptibility profile, type, and severity of infection and the features of the patient.

Escherichia coli: an old friend with new tidings

Escherichia coli is one of the most-studied microorganisms worldwide but its characteristics are continually changing. Extraintestinal E. coli infections, such as urinary tract infections and neonatal sepsis, represent a huge public health problem. They are caused mainly by specialized extraintestinal pathogenic E. coli (ExPEC) strains that can innocuously colonize human hosts but can also cause disease upon entering a normally sterile body site. The virulence capability of such strains is determined by a combination of distinctive accessory traits, called virulence factors, in conjunction with their distinctive phylogenetic background. It is conceivable that by developing interventions against the most successful ExPEC lineages or their key virulence/colonization factors the associated burden of disease and health care costs could foreseeably be reduced in the future. On the other hand, one important problem worldwide is the increase of antimicrobial resistance shown by bacteria. As underscored in the last WHO global report, within a wide range of infectious agents including E. coli, antimicrobial resistance has reached an extremely worrisome situation that ‘threatens the achievements of modern medicine’. In the present review, an update of the knowledge about the pathogenicity, antimicrobial resistance and clinical aspects of this ‘old friend’ was presented.

Empiric Therapy With Carbapenem-Sparing Regimens for Bloodstream Infections due to Extended-Spectrum β-Lactamase-Producing Enterobacteriaceae: Results From the INCREMENT Cohort

BACKGROUND

There is little information about the efficacy of active alternative drugs to carbapenems except β-lactam/β-lactamase inhibitors for the treatment of bloodstream infections (BSIs) due to extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E). The objective of this study was to assess the outcomes of patients with BSI due to ESBL-E who received empiric therapy with such drugs (other active drugs [OADs]) or carbapenems.

METHODS

A multinational retrospective cohort study of patients with BSI due to ESBL-E who received empiric treatment with OADs or carbapenems was performed. Cox regression including a propensity score for receiving OADs was performed to analyze 30-day all-cause mortality as main outcome. Clinical failure and length of stay were also analyzed.

RESULTS

Overall, 335 patients were included; 249 received empiric carbapenems and 86 OADs. The most frequent OADs were aminoglycosides (43 patients) and fluoroquinolones (20 patients). Empiric therapy with OADs was not associated with mortality (hazard ratio [HR], 0.75; 95% confidence interval [CI], .38-1.48) in the Cox regression analysis. Propensity score-matched pairs, subgroups, and sensitivity analyses did not show different trends; specifically, the adjusted HR for aminoglycosides was 1.05 (95% CI, .51-2.16). OADs were neither associated with 14-day clinical failure (adjusted odds ratio, 0.62; 95% CI, .29-1.36) nor length of hospital stay.

CONCLUSIONS

We were unable to show that empiric treatment with OAD was associated with a worse outcome compared with carbapenems. This information allows more options to be considered for empiric therapy, at least for some patients, depending on local susceptibility patterns of ESBL-E.

Development and validation of the INCREMENT-ESBL predictive score for mortality in patients with bloodstream infections due to extended-spectrum-β-lactamase-producing Enterobacteriaceae

Background

Bloodstream infections (BSIs) due to ESBL-producing Enterobacteriaceae (ESBL-E) are frequent yet outcome prediction rules for clinical use have not been developed. The objective was to define and validate a predictive risk score for 30 day mortality.

Methods

A multinational retrospective cohort study including consecutive episodes of BSI due to ESBL-E was performed; cases were randomly assigned to a derivation cohort (DC) or a validation cohort (VC). The main outcome variable was all-cause 30 day mortality. A predictive score was developed using logistic regression coefficients for the DC, then tested in the VC.

Results

The DC and VC included 622 and 328 episodes, respectively. The final multivariate logistic regression model for mortality in the DC included age >50 years (OR = 2.63; 95% CI: 1.18-5.85; 3 points), infection due to Klebsiella spp. (OR = 2.08; 95% CI: 1.21-3.58; 2 points), source other than urinary tract (OR = 3.6; 95% CI: 2.02-6.44; 3 points), fatal underlying disease (OR = 3.91; 95% CI: 2.24-6.80; 4 points), Pitt score >3 (OR = 3.04; 95 CI: 1.69-5.47; 3 points), severe sepsis or septic shock at presentation (OR = 4.8; 95% CI: 2.72-8.46; 4 points) and inappropriate early targeted therapy (OR = 2.47; 95% CI: 1.58-4.63; 2 points). The score showed an area under the receiver operating curve (AUROC) of 0.85 in the DC and 0.82 in the VC. Mortality rates for patients with scores of < 11 and ≥11 were 5.6% and 45.9%, respectively, in the DC, and 5.4% and 34.8% in the VC.

Conclusions

We developed and validated an easy-to-collect predictive scoring model for all-cause 30 day mortality useful for identifying patients at high and low risk of mortality.

A comparison of blood stream infections with extended spectrum beta-lactamase-producing and non-producing Klebsiella pneumoniae in pediatric patients

Background

Rapid development and global spread of multidrug resistant Klebsiella pneumonia (K. pneumoniae) as a major cause of nosocomial infections is really remarkable. The aim of this study was to explore risk factors for health care associated blood stream infections (BSI) caused by ESBL-producing K. pneumoniae in children and analyze clinical outcomes.

Methods

A retrospective review of patients younger than 18 years-old with blood stream infection caused by K. pneumoniae was performed. Patients with ESBL-producing K. pneumoniae isolates were compared with ESBL-non-producing isolates in terms of risk factors, outcome and mortality.

Results

Among 111 K. pneumoniae isolates 62% (n = 69) were ESBL –producing K. pneumoniae. The median total length of hospitalization and median length of stay in hospital before infection was significantly higher in patients with ESBL-producing isolates than ESBL-non-producing. Use of combined antimicrobial treatment was significantly different between ESBL-producing and ESBL-non-producing groups, 75.4% and 24.6%, respectively (p = 0.001). Previous aminoglycoside use was higher in cases with ESBL –producing isolates (p = 0.001). Logistic regression analysis showed a significant correlation between mortality and use of combined antibiotics (OR 4.22; p = 0.01).

Conclusion

ESBL production in K. pneumoniae isolates has a significant impact on clinical course of BSIs. Total length of hospitalization, length of hospital stay before infection, prior combined antibiotic use and use of aminoglycosides were significant risk factors for development of ESBL-producing K. pneumoniae related BSI.

The Continuing Plague of Extended-spectrum β-lactamase-producing Enterobacteriaceae Infections

Antimicrobial resistance is a common iatrogenic complication of modern life and medical care. One of the most demonstrative examples is the exponential increase in the incidence of extended-spectrum β-lactamases (ESBLs) production among Enterobacteriaceae, which is the most common human pathogens outside of the hospital settings. Infections resulting from ESBL-producing bacteria are associated with devastating outcomes, now affecting even previously healthy individuals. This development poses an enormous burden and threat to public health. This paper aims to narrate the evolving epidemiology of ESBL infections, and highlight current challenges in terms of management and prevention of these common infections.

Phenotypic characterization of extended-spectrum-beta-lactamase producing E. coli from healthy individuals, patients, sewage sludge, cattle, chickens and raw meat

Objective:

The present study aimed to determine the frequency and antimicrobial profile of ESBL-producing isolates of E. coli in different environments.

Methods:

This cross-sectional study was conducted at The Children’s Hospital and The Institute of Child Health, Lahore from July to December 2015. The faecal specimens from healthy individuals, patients, sewage sludge, cattle, chickens and raw meat (n = 122) were processed for microbiological analysis using MacConkey agar supplemented with cefotaxime. The identification of organisms was confirmed by API 10S and antimicrobial resistance profile was recorded by Kirby-Bauer disc diffusion method.

Results:

On the basis of screening, 77 (63.0%) specimens were found to be positive for ESBL production. The confirmation of 74 (60.0%) ESBL producing E. coli was done using double disc synergy test (DDST). The frequency of ESBL producing E. coli was found to be 17 (57.0%) in healthy individuals, 15 (53.0%) in patients, 10 (66.0%) in cattle faeces, 5 (71.0%) in sewage sludge, 14 (70.0%) in raw meat and 13 (59.0%) in chicken faeces. All of these isolates were resistant to cephalosporins and some of these were resistant to fluoroquinolones and meropenem. None of the isolates showed resistance to cefoperazone-sulbactam, imipenem, piperacillin-tazobactam and amikacin.

Conclusion:

The prevalence of ESBL-producing E. coli was recorded in all the environments, suggesting a global expansion of these enzymes.

Randomized controlled trial of piperacillin-tazobactam, cefepime and ertapenem for the treatment of urinary tract infection caused by extended-spectrum beta-lactamase-producing Escherichia coli

BACKGROUND

Due to limited therapeutic options, the spread of extended-spectrum beta-lactamases (ESBLs) have become a major public health concern. We conducted a prospective, randomized, open-label comparison of the therapeutic efficacy of piperacillin-tazobactam (PTZ), cefepime, and ertapenem in febrile nosocomial urinary tract infection with ESBL-producing Escherichia coli (ESBL-EC).

METHODS

This study was conducted at three university hospitals between January 2013 and August 2015. Hospitalized adult patients presenting with fever were screened for healthcare-associated urinary tract infection (HA-UTI). When ESBL-EC was solely detected and susceptible to a randomized antibiotic in vitro, the case was included in the final analysis. Participants were treated for 10-14 days with PTZ, cefepime, or ertapenem.

RESULTS

A total of 66 participants were evenly assigned to the PTZ and ertapenem treatment groups. After the recruitment of six participants, assignment to the cefepime treatment group was stopped because of an unexpectedly high treatment failure rate. The baseline characteristics of these participants did not differ from participants in other treatment groups. The clinical and microbiological response to PTZ treatment was estimated to be 94% and was similar to the response to ertapenem treatment. The efficacy of cefepime was 33.3%. In the cefepime group, age, Charlson comorbidity index, genotype, and minimal inhibitory concentration (MIC) did not significantly affect the success of treatment. Similarly, genotype seemed to be irrelevant with respect to clinical outcome in the PTZ group. Expired cases tended to involve septic shock with a high Charlson comorbidity index and high MIC.

CONCLUSION

Results from this study suggest that PTZ is effective in the treatment of urinary tract infection caused by ESBL-EC when the in vitro test indicates susceptibility. In addition, cefepime should not be used as an alternative treatment for urinary tract infection caused by ESBL-EC.

TRIAL REGISTRATION

The trial was registered with the Clinical Research Information Service of Korea Centers for Disease Control and Prevention. (KCT0001895).

Clinical efficacy of β-lactam/β-lactamase inhibitor combinations for the treatment of bloodstream infection due to extended-spectrum β-lactamase-producing Enterobacteriaceae in haematological patients with neutropaenia: a study protocol for a retrospective observational study (BICAR)

INTRODUCTION

Bloodstream infection (BSI) due to extended-spectrum β-lactamase-producing Gram-negative bacilli (ESBL-GNB) is increasing at an alarming pace worldwide. Although β-lactam/β-lactamase inhibitor (BLBLI) combinations have been suggested as an alternative to carbapenems for the treatment of BSI due to these resistant organisms in the general population, their usefulness for the treatment of BSI due to ESBL-GNB in haematological patients with neutropaenia is yet to be elucidated. The aim of the BICAR study is to compare the efficacy of BLBLI combinations with that of carbapenems for the treatment of BSI due to an ESBL-GNB in this population.

METHODS AND ANALYSIS

A multinational, multicentre, observational retrospective study. Episodes of BSI due to ESBL-GNB occurring in haematological patients and haematopoietic stem cell transplant recipients with neutropaenia from 1 January 2006 to 31 March 2015 will be analysed. The primary end point will be case-fatality rate within 30 days of onset of BSI. The secondary end points will be 7-day and 14-day case-fatality rates, microbiological failure, colonisation/infection by resistant bacteria, superinfection, intensive care unit admission and development of adverse events.

SAMPLE SIZE

The number of expected episodes of BSI due to ESBL-GNB in the participant centres will be 260 with a ratio of control to experimental participants of 2.

ETHICS AND DISSEMINATION

The protocol of the study was approved at the first site by the Research Ethics Committee (REC) of Hospital Universitari de Bellvitge. Approval will be also sought from all relevant RECs. Any formal presentation or publication of data from this study will be considered as a joint publication by the participating investigators and will follow the recommendations of the International Committee of Medical Journal Editors (ICMJE). The study has been endorsed by the European Study Group for Bloodstream Infection and Sepsis (ESGBIS) and the European Study Group for Infections in Compromised Hosts (ESGICH).

In vitro Effectiveness of Commercial Bacteriophage Cocktails on Diverse Extended-Spectrum Beta-Lactamase Producing Escherichia coli Strains

The objective of this study is to determine the in vitro susceptibility of Georgian bacteriophage cocktails on multidrug resistant (MDR) extended-spectrum beta-lactamase producing Escherichia coli (ESBL-EC) isolated from patients’ blood and urine cultures. A total of 615 E. coli isolates were included in this study. Phene Plate (PhP)-typing and phylogenetic grouping were used for the typing. Antimicrobial resistance profiles and ESBL production of all isolates were confirmed according to Clinical and Laboratory Standards Institute (CLSI) criteria. The activities of four bacteriophage cocktails (Enko-phage, SES-bacteriophage, Pyo-bacteriophage, and Intesti-bacteriophage) were determined against 142 ESBL-EC using in vitro spot tests. According to this, Enko-phage were active against 87.3% of the tested strains while that ratio was 81.7% for Intesti-bacteriophage, 81.7% for Pyo-bacteriophage, and 59.2% for SES-bacteriophage cocktails. Based on the contingency tests, the phage cocktails were observed to be statistically significantly (p < 0.001) more effective on ESBL-EC strains belonging to phylogenetic groups D and B2. The employed phage cocktails were found to be affective against all tested resistant types. These results are promising especially for the infections that are caused by MDR pathogens that are difficult to treat. As this is a preliminary step to the potential clinical trials to be designed for the country, in vitro confirmation of their success on a MDR ESBL-EC collection should be accepted as an initial action, which is encouraging to consider clinical trials of phage therapy especially in countries which are not introduce phage therapy.

Colonisation with extended-spectrum β-lactamase-producing Enterobacteriaceae and risk for infection among patients with solid or haematological malignancy: a systematic review and meta-analysis

Cancer patients are vulnerable to infections, including those with extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-PE), and most of these infections are associated with colonisation of the gastrointestinal tract. The aim of this study was to estimate the prevalence of gastrointestinal colonisation with ESBL-PE cancer populations and to determine the risk for subsequent bloodstream infection (BSI) with these pathogens. PubMed and EMBASE databases were searched from 1 January 1991 to 1 March 2016 to identify studies regarding ESBL-PE colonisation among patients with malignancies. Ten studies (out of 561 non-duplicate articles) were included, providing data on 2211 patients. The pooled prevalence of ESBL-PE colonisation was 19% [95% confidence interval (CI) 8-32%]. Stratifying per region, the pooled prevalence in Europe was 15% (95% CI 10-21%), whereas in Asia the pooled prevalence was 31% (95% CI 4-69%). In addition, the pooled prevalence was 15% (95% CI 7-24%) among patients with haematological malignancy, whereas no studies were identified that included solely patients with solid tumours. Notably, cancer patients with ESBL-PE colonisation were 12.98 times (95% CI 3.91-43.06) more likely to develop a BSI with ESBL-PE during their hospitalisation compared with non-colonised patients. We found that, overall, one in five patients with cancer is colonised with ESBL-PE and the incidence can be as high as one in three in Asia. This is important because colonisation was associated with an almost 13 times higher risk for developing BSI with ESBL-PE. Screening measures should be evaluated to identify their clinical benefit in patients with malignancy.

Longitudinal study of CTX-M ESBL-producing E. coli strains on a UK dairy farm

The aim of this study was to investigate the bacterial strains and farm environment that may contribute to the persistence of ESBL-producing E. coli on a single UK dairy farm. A longitudinal study was conducted comprising 6 visits, between August and October 2010, followed by a further visit at approximately 69weeks after the initial visit. Faecal and environmental samples were collected from different parts of the farm. The persistence and extent of faecal shedding of ESBL E. coli by individual calves was also determined. Twenty two different PFGE types were identified. Four of these were persistent during the study period and were associated with serotypes: O98, O55, O141 and O33. The counts suggest that shedding in calf faeces was an important factor for the persistence of strains, and the data will be useful for parameterising mathematical models of the spread and persistence of ESBL strains within a dairy farm.

ESBL Detection: Comparison of a Commercially Available Chromogenic Test for Third Generation Cephalosporine Resistance and Automated Susceptibility Testing in Enterobactericeae

Rapid detection and reporting of third generation cephalosporine resistance (3GC-R) and of extended spectrum betalactamases in Enterobacteriaceae (ESBL-E) is a diagnostic and therapeutic priority to avoid inefficacy of the initial antibiotic regimen. In this study we evaluated a commercially available chromogenic screen for 3GC-R as a predictive and/or confirmatory test for ESBL and AmpC activity in clinical and veterinary Enterobacteriaceae isolates. The test was highly reliable in the prediction of cefotaxime and cefpodoxime resistance, but there was no correlation with ceftazidime and piperacillin/tazobactam minimal inhibitory concentrations. All human and porcine ESBL-E tested were detected with exception of one genetically positive but phenotypically negative isolate. By contrast, AmpC detection rates lay below 30%. Notably, exclusion of piperacillin/tazobactam resistant, 3GC susceptible K1+ Klebsiella isolates increased the sensitivity and specificity of the test for ESBL detection. Our data further imply that in regions with low prevalence of AmpC and K1 positive E. coli strains chromogenic testing for 3GC-R can substitute for more time consuming ESBL confirmative testing in E. coli isolates tested positive by Phoenix or VITEK2 ESBL screen. We, therefore, suggest a diagnostic algorithm that distinguishes 3GC-R screening from primary culture and species-dependent confirmatory ESBL testing by βLACTATM and discuss the implications of MIC distribution results on the choice of antibiotic regimen.

A Multinational, Preregistered Cohort Study of β-Lactam/β-Lactamase Inhibitor Combinations for Treatment of Bloodstream Infections Due to Extended-Spectrum-β-Lactamase-Producing Enterobacteriaceae

The spread of extended-spectrum-β-lactamase (ESBL)-producing Enterobacteriaceae (ESBL-E) is leading to increased carbapenem consumption. Alternatives to carbapenems need to be investigated. We investigated whether β-lactam/β-lactamase inhibitor (BLBLI) combinations are as effective as carbapenems in the treatment of bloodstream infections (BSI) due to ESBL-E. A multinational, retrospective cohort study was performed. Patients with monomicrobial BSI due to ESBL-E were studied; specific criteria were applied for inclusion of patients in the empirical-therapy (ET) cohort (ETC; 365 patients), targeted-therapy (TT) cohort (TTC; 601 patients), and global cohort (GC; 627 patients). The main outcome variables were cure/improvement rate at day 14 and all-cause 30-day mortality. Multivariate analysis, propensity scores (PS), and sensitivity analyses were used to control for confounding. The cure/improvement rates with BLBLIs and carbapenems were 80.0% and 78.9% in the ETC and 90.2% and 85.5% in the TTC, respectively. The 30-day mortality rates were 17.6% and 20% in the ETC and 9.8% and 13.9% in the TTC, respectively. The adjusted odds ratio (OR) (95% confidence interval [CI]) values for cure/improvement rate with ET with BLBLIs were 1.37 (0.69 to 2.76); for TT, they were 1.61 (0.58 to 4.86). Regarding 30-day mortality, the adjusted OR (95% CI) values were 0.55 (0.25 to 1.18) for ET and 0.59 (0.19 to 1.71) for TT. The results were consistent in all subgroups studied, in a stratified analysis according to quartiles of PS, in PS-matched cases, and in the GC. BLBLIs, if active in vitro, appear to be as effective as carbapenems for ET and TT of BSI due to ESLB-E regardless of the source and specific species. These data may help to avoid the overuse of carbapenems. (This study has been registered at ClinicalTrials.gov under registration no. NCT01764490.).

Colonization of multidrug resistant pathogens in a hybrid pediatric cardiac surgery center

INTRODUCTION

The incidence of multidrug resistant microorganisms worldwide is increasing. The aim of the study was to present institutional experience with the multidrug resistant microorganism colonization patterns observed in children with congenital heart diseases hospitalized in a hybrid pediatric cardiac surgery center.

MATERIAL AND METHODS

Microbiological samples were routinely collected in all children admitted to our department. All microbiological samples were analyzed with regard to multidrug resistant microorganisms: methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), Gram-negative rods producing extended-spectrum beta-lactamases (ESBL), multidrug resistant Gram-negative rods (MDR-GNRs), carbapenemase-producing Klebsiella pneumoniae (KPC), carbapenem-resistant Acinetobacter baumannii (CRAB) and Pseudomonas aeruginosa (CRPA).

RESULTS

In 30 (9%) swabs 'alert' pathogens from the above group of listed microorganisms were found. All positive swabs were isolated in 19 (16.1%) children. Multidrug resistant pathogen colonization was statistically significantly more often observed in children admitted from other medical facilities than in children admitted from home (38% vs. 10%, p = 0.0089). In the group of children younger than 6 months 'alert' pathogen were more often observed than in older children (34.1% vs. 5.4%, p < 0.001).

CONCLUSIONS

Preoperative multidrug resistant pathogen screening in children admitted and referred for congenital heart disease procedures may be of great importance since many of these patients are colonized with resistant bacteria. Knowledge of the patient's microbiome is important in local epidemiological control along with tailoring the most effective preoperative prophylactic antibiotic for each patient. The impact of preoperative screening on postoperative infections and other complications requires further analysis.