Carbapenemase-producing Enterobacteriaceae in Europe: a survey among national experts from 39 countries, February 2013

Retrospective Analysis of Antibiotic Resistance Patterns of Uropathogenic Escherichia coli With Focus on Extended-Spectrum β-Lactamase at a Tertiary Central Hospital in Saudi Arabia

Background and Aims

Urinary tract infections (UTIs) are a prevalent bacterial infection that has substantial implications for healthcare on a global scale. Escherichia coli (E. coli) is a gram-negative rod responsible for most UTI cases. ESBL-producing E. coli is widely recognized as a significant contributor to antibiotic resistance. This study aims to evaluate the prevalence and antibiotic resistance trends of ESBL-producing E. coli in patients with UTIs at a tertiary hospital in Jazan, Saudi Arabia.

Methods

A retrospective cross-sectional analysis was conducted on 347 urine specimens collected between January 2022 and March 2023.

Results

The study found that 31% of E. coli specimens were positive for ESBL. Among patients with ESBL-producing E. coli, 78.9% were females, and the majority of ESBL-producing E. coli cases were observed in the outpatient clinic departments. Among all E. coli isolates, ampicillin exhibited the highest resistance rate at 69.3%, aztreonam at 66.7%, and colistin at the lowest resistance. ESBL-producing E. coli strains exhibited higher resistance rates than non-ESBL-producing E. coli strains.

Conclusion

The study agrees with others in the region and shows a higher prevalence of ESBL-producing E. coli in the region, emphasizing the importance of antibiotic stewardship programs and infection control measures to mitigate the prevalence and spread of ESBL-producing E. coli in our region.

Reducing Peptidoglycan Crosslinking by Chemical Modulator Reverts β-lactam Resistance in Methicillin-Resistant Staphylococcus aureus

Small molecule can be utilized to restore the effectiveness of existing major classes of antibiotics against antibiotic-resistant bacteria. In this study, it is demonstrated that celastrol, a natural compound, can modify the bacterial cell wall and subsequently render bacteria more suceptible to β-lactam antibiotics. It is shown that celastrol leads to incomplete cell wall crosslinking by modulating levels of c-di-AMP, a secondary messenger, in methicillin-resistant Staphylococcus aureus (MRSA). This mechanism enables celastrol to act as a potentiator, effectively rendering MRSA susceptible to a range of penicillins and cephalosporins. Restoration of in vivo susceptibility of MRSA to methicillin is also demonstrated using a sepsis animal model by co-administering methicillin along with celastrol at a much lower amount than that of methicillin. The results suggest a novel approach for developing potentiators for major classes of antibiotics by exploring molecules that re-program metabolic pathways to reverse β-lactam-resistant strains to susceptible strains.

Synergistic Combination of Aztreonam and Ceftazidime-Avibactam-A Promising Defense Strategy against OXA-48 + NDM Klebsiella pneumoniae in Romania

With the increasing burden of carbapenem-resistant Klebsiella pneumoniae (CR-Kp), including high rates of healthcare-associated infections, treatment failure, and mortality, a good therapeutic strategy for attacking this multi-resistant pathogen is one of the main goals in current medical practice and necessitates the use of novel antibiotics or new drug combinations.

OBJECTIVES

We reviewed the clinical and microbiological outcomes of seven patients treated at the "Agrippa Ionescu" Clinical Emergency Hospital between October 2023 and January 2024, aiming to demonstrate the synergistic activity of the ceftazidime-avibactam (C/A) plus aztreonam (ATM) combination against the co-producers of blaNDM + blaOXA-48-like CR-Kp.

MATERIAL AND METHODS

Seven CR-Kp with blaNDM and blaOXA-48 as resistance mechanisms were tested. Seven patients treated with C/A + ATM were included. The synergistic activity of C/A + ATM was proven through double-disk diffusion in all seven isolates. Resistance mechanisms like KPC, VIM, OXA-48, NDM, IMP, and CTX-M were assessed through immunochromatography.

RESULTS

With a mean of nine days of treatment with the synergistic combination C/A + ATM, all patients achieved clinical recovery, and five achieved microbiological recovery.

CONCLUSIONS

With the emerging co-occurrence of blaOXA-48 and blaNDM among Kp in Romania, the combination of C/A and ATM could be a promising therapeutic option.

Investigating Resistance to Carbapenems in Enterobacterales: A Descriptive Epidemiological Study of 2021 Screening in an Italian Teaching Hospital

Antimicrobial resistance (AMR) presents a growing threat to global healthcare. This descriptive epidemiological study investigates the prevalence and characteristics of Enterobacterales with AMR factors in a tertiary teaching hospital in Italy over the course of the year 2021. In 2021, the prevalence of colonisation by Enterobacterales with AMR factors in patients was 1.08%. During the observation period, a total of 8834 rectal swabs were performed, with 1453 testing positive. A total of 5639 rectal swabs were performed according to a hospital procedure for the active screening of MDRO colonisation at the time of admission. Of these, 679 were positive for microorganisms under surveillance, and 74 patients were colonised with Enterobacterales, predominantly Klebsiella pneumoniae and Escherichia coli. Antibiotic resistance factors were observed in 61 of these 74 patients (82.43%) of these patients, with NDM and KPC being the most frequent resistance factors. A statistically significant trend in positive swabs was observed across different ward categories (surgery, ICUs, and medical wards). Regarding specific trends, the rate of positive admission screening in medical and surgical wards was higher than in ICU wards. The results highlight the ease with which Enterobacterales develops resistance across different ward categories. The findings underscore the need for adjusted screening protocols and tailored infection prevention strategies in various care settings.

Hospital-Acquired Infections Caused by Carbapenem-Resistant Enterobacteriaceae: An Observational Study

Worldwide, hospital-acquired infections (HAIs) are continuously rising within healthcare settings, leading to high mortality and morbidity rates. Many hospitals have reported the spread of carbapenemases globally, specifically within the E. coli and K. pneumoniae species. This study was aimed at analyzing the state of hospital-acquired, carbapenem-resistant E. coli and K. pneumoniae in the United Kingdom between 2009 and 2021. Moreover, the study analyzed the most efficacious approaches to patient management for controlling the carbapenem-resistant Enterobacteriaceae (CRE) spread. Initially, 1094 articles were identified as relevant for screening, and among them, 49 papers were eligible for full-text screening, with a total of 14 articles meeting the inclusion criteria. The information was recorded from published articles through PubMed, the Web of Science, Scopus, Science Direct, and the Cochrane library and was used to search for hospital-acquired carbapenem-resistant E. coli and K pneumoniae in the UK between 2009 and 2021, in order to evaluate the spread of CRE in hospitals. The total number of carbapenem-resistant E. coli was 1083 and this was 2053 for carbapenem-resistant K. pneumoniae in more than 63 UK hospitals. KPC was the dominant carbapenemase produced by K. pneumoniae. The results showed that the treatment options considered depended on the type of carbapenemase produced; K. pneumoniae showed more resistance to a treatment options, i.e., Colistin, than the other carbapenemase. The current state of the UK is at minimal risk for a CRE outbreak; however, appropriate treatment and infection control measures are highly required to prevent this CRE spread at the regional and global levels. The present study findings have an important message for physicians, healthcare workers, and policymakers about hospital-acquired carbapenem-resistant E. coli and K. pneumoniae spread and approaches to patient management.

Individualized active surveillance for carbapenem-resistant microorganisms using Xpert Carba-R in intensive care units

Carbapenem antibiotics are widely used in ICU, and the prevalence of carbapenem-resistant microorganisms (CRO) has increased. This study aimed to assess the role of individualized active surveillance using Xpert Carba-R of carbapenem resistance genes on CRO risk. A total of 3,765 patients were admitted to the ICU of Zhongnan Hospital of Wuhan University between 2020 and 2022. The presence of carbapenem resistance genes were monitored using Xpert Carba-R, and CRO incidence was assigned as the investigated outcome. Of 3,765 patients, 390 manifested the presence of CRO, representing a prevalence of 10.36%. Active surveillance using Xpert Carba-R was associated with a lower CRO risk (odds ratio [OR]: 0.77; 95% confidence interval [CI] 0.62-0.95; P = 0.013), especially for carbapenem-resistant Acinetobacter + carbapenem-resistant Pseudomonas aeruginosa (OR: 0.79; 95% CI 0.62-0.99; P = 0.043), carbapenem-resistant Klebsiella pneumoniae (OR: 0.56; 95% CI 0.40-0.79; P = 0.001), and carbapenem-resistant Enterobacteriaceae (OR: 0.65; 95% CI 0.47-0.90; P = 0.008). Individualized active surveillance using Xpert Carba-R may be associated with a reduction in the overall CRO incidence in ICU. Further prospective studies should be performed to verify these conclusions and guide further management of patients in ICU.

Resistance, Tolerance, Virulence and Bacterial Pathogen Fitness-Current State and Envisioned Solutions for the Near Future

The current antibiotic crisis and the global phenomena of bacterial resistance, inherited and non-inherited, and tolerance-associated with biofilm formation-are prompting dire predictions of a post-antibiotic era in the near future. These predictions refer to increases in morbidity and mortality rates as a consequence of infections with multidrug-resistant or pandrug-resistant microbial strains. In this context, we aimed to highlight the current status of the antibiotic resistance phenomenon and the significance of bacterial virulence properties/fitness for human health and to review the main strategies alternative or complementary to antibiotic therapy, some of them being already clinically applied or in clinical trials, others only foreseen and in the research phase.

Overview of Virulence and Antibiotic Resistance in Campylobacter spp. Livestock Isolates

Campylobacter remains the most prevalent foodborne pathogen bacterium responsible for causing gastroenteritis worldwide. Specifically, this pathogen colonises a ubiquitous range of environments, from poultry, companion pets and livestock animals to humans. The bacterium is uniquely adaptable to various niches, leading to complicated gastroenteritis and, in some cases, difficult to treat due to elevated resistance to certain antibiotics. This increased resistance is currently detected via genomic, clinical or epidemiological studies, with the results highlighting worrying multi-drug resistant (MDR) profiles in many food and clinical isolates. The Campylobacter genome encodes a rich inventory of virulence factors offering the bacterium the ability to influence host immune defences, survive antimicrobials, form biofilms and ultimately boost its infection-inducing potential. The virulence traits responsible for inducing clinical signs are not sufficiently defined because several populations have ample virulence genes with physiological functions that reflect their pathogenicity differences as well as a complement of antimicrobial resistance (AMR) systems. Therefore, exhaustive knowledge of the virulence factors associated with Campylobacter is crucial for collecting molecular insights into the infectivity processes, which could pave the way for new therapeutical targets to combat and control the infection and mitigate the spread of MDR bacteria. This review provides an overview of the spread and prevalence of genetic determinants associated with virulence and antibiotic resistance from studies performed on livestock animals. In addition, we have investigated the relevant coincidental associations between the prevalence of the genes responsible for pathogenic virulence, horizontal gene transfer (HGT) and transmissibility of highly pathogenic Campylobacter strains.

Prevalence, incidence and risk factors for acquisition and colonization of extended-spectrum beta-lactamase- and carbapenemase-producing Enterobacteriaceae from dogs attended at a veterinary hospital in Spain

The last 10 years have seen a progressive increase in antibiotic resistance rates in bacteria isolated from companion animals. Exposure of individuals to resistant bacteria from companion animals, such as extended-spectrum beta-lactamase- (ESBL) and carbapenemase- (CPE) producing Enterobacteriaceae, can be propitiated. Few studies evaluate the incidence and risk factors associated with colonization by multidrug-resistant bacteria in dogs. This work aims to estimate the prevalence, incidence and risk factors associated with colonization of ESBL-E and CPE-E in 44 canine patients hospitalized in a veterinary hospital. The antimicrobial susceptibility of Enterobacteriaceae strains was analyzed and the molecular detection of resistant genes was performed. A prevalence of 25.0% and an incidence of ESBL-E of 45.5% were observed in dogs colonized by Enterobacteriaceae at hospital admission and release, respectively. Escherichia coli, Klebsiella pneumoniae, Citrobacter koseri and Morganella morganii were identified as ESBL-producing bacterial species. Resistance genes were detected for ESBL-producing strains. No CPE isolates were obtained on the CPE-selective medium. The administration of corticosteroids prior to hospitalization and the presence of concomitant diseases were associated with colonization by these bacteria in dogs. Considering that one-quarter of the patients evaluated were colonized by ESBL-E, companion animals should be considered as potential transmission vehicles and ESBL-E reservoirs for humans. Special care should be taken in animals attended at veterinary hospitals, as the length of stay in the hospital could increase the risks.

Antibacterial and antibiofilm activity of Lactobacillus strains secretome and extraction against Escherichia coli isolated from urinary tract infection

The purpose of this study was to antibacterial, and antibiofilm activity of two Lactobacillus strains secretome and extraction against E. coli isolated from women with urinary tract infection (UTI). We isolated 100 E. coli samples from women with UTI. Lactobacillus acidophilus and Lactobacillus casei characteristics were evaluated, and their secretome and extraction were prepared. The antibacterial and antibiofilm activity of secretome and extraction of both Lactobacillus strains were evaluated against isolated E. coli samples. L. acidophilus and L. casei were able to tolerate pH 3, bile salts, and pancreatic enzymes. Both probiotics were not resistant to antibiotics and demonstrated an appropriate ability to adhere to the intestinal epithelial cells. Secretome and extraction of L. acidophilus and L. casei strains showed a good antibacterial and antibiofilm against E. coli isolates. Generally, present study suggested that the secretome and extraction of L. acidophilus and L. casei strains exhibits a good antimicrobial activity.

Rapid detection of KPC-producing Enterobacterales by using a modified Carba NP test with imipenem/relebactam

INTRODUCTION

Here, we propose a novel modified Carba NP test for detecting KPC-producing Enterobacterales using imipenem/relebactam.

MATERIAL AND METHODS

The test performance was evaluated in a random selection of 160 previously molecularly characterized clinical isolates carrying the 110 bla_KPC, 1 bla_GES, 12 bla_VIM, 4 bla_IMP, 3 bla_NDM and 42 bla_OXA-48-like genes. The proposed method relies on the detection of imipenem hydrolysis in an imipenem/relebactam antibiotic solution and subsequent visual interpretation by color change.

RESULTS

All class A producing Enterobacterales (111/111) were detected using imipenem/relebactam as no visual appreciation of color change was perceived due to a nule hydrolysis of imipenem in the antibiotic solution. Overall, the assay showed 100% sensitivity (111/111) and specificity (69/69) for detecting class A KPC-producing Enterobacterales.

DISCUSSION

The biochemical assay provides very reliable results for detecting KPC-producing Enterobacterales, with a turnaround time of less than 1 hour, minimum handling and no specialized equipment required.

The Prevalence of Multidrug-Resistant Escherichia coli Producing ESBL among Male and Female Patients with Urinary Tract Infections in Riyadh Region, Saudi Arabia

The Escherichia coli that produces extended-spectrum lactamases (ESBL-E. coli) can develop resistance to many antibiotics. The control of ESBL-E. coli disorders is challenging due to their restricted therapeutic approaches, so this study aims to determine the prevalence and pattern of the antibiotic resistance of ESBL-E. coli among male and female patients with urinary tract infections in Riyadh, Saudi Arabia. During the period of 2019 to 2020 at King Fahd Medical City, Riyadh, 2250 urine samples from patients with urinary tract infections (UTIs) were collected, and microbial species were cultured and identified using standard biochemical techniques. A double-disc synergy test was used to identify ESBL-producing strains of E. coli, and an in vitro method and the clinical laboratory standard institute (CLSI) criteria were employed to determine the resistance of these strains to antimicrobial drugs. ESBL-E. coli was detected in 510 (33.49%) of the 1523 E. coli isolates, 67.27% of which were recovered from women and 33.7% of which were recovered from men. A total of 284 (55.69%) ESBL-E. coli isolates were found in patients under 50 years of age, and 226 (44.31%) were found in patients over 50 years of age. Nearly all the isolates of ESBL-E. coli were resistant to cephalosporins (ceftriaxone, cefotaxime, cefepime, cefuroxime, and cephalothin) and penicillin (ampicillin), whereas the majority of the isolates were sensitive to several carbapenems (imipenem, meropenem, and ertapenem), aminoglycosides (amikacin), and nitrofurantoins. The development of antibiotic resistance by ESBL-E. coli, the most frequent pathogen linked to urinary tract infections, plays a crucial role in determining which antibiotic therapy is appropriate.

Carbapenem-resistant Enterobacterales in patients with bacteraemia at tertiary academic hospitals in South Africa, 2019 - 2020: An update

Background. The emergence of carbapenem-resistant Enterobacterales (CRE) has become a serious and significant public health threat worldwide, owing to the limited antimicrobial therapy options, and the elevated mortality rates associated with these infections.Objectives. To present an update on the epidemiology of CRE bloodstream infections among hospitalised patients reported under the Group for Enteric, Respiratory and Meningeal Diseases Surveillance in South Africa (GERMS-SA) between January 2019 and December 2020. Methods. Patients of all ages with CRE bacteraemia were included and isolates, when available, were sent to the reference laboratory for confirmatory testing and molecular characterisation. Multivariable logistic regression analysis was performed to assess factors associated with in-hospital mortality. Results. We included 2 144 patients with CRE bacteraemia with a median age of 33 (interquartile range 1 - 51) years, of whom 1 145 (54.2%) were male. Klebsiella pneumoniae accounted for 79.8% of infections (n=863/1 082), of which 89.5% (n=611/683) were healthcare associated (HA). The most common carbapenemase genes were carbapenem-hydrolysing oxacillinase-48 (blaOXA-48-like) (76.8%; n=761/991), New Delhi metallo-β-lactamase (blaNDM) (21.1%; n=209/991) and Verona integron-encoded metallo-β-lactamase (blaVIM) (1.3%; n=13/991). None of the screened isolates with a colistin minimum inhibitory concentration >2 μg/mL harboured the mobilised colistin resistance (mcr)-1 to mcr-5 genes. The crude in-hospital mortality rate was 36.6% (n=377/1 029). Patients aged ≥60 years (v. 1.6 - 9 years) (adjusted odds ratio (aOR) 4.53; 95% confidence interval (CI) 2.21 - 9.28), those with comorbidities (diabetes, malignancy, renal and/or cardiovascular failure) (aOR 1.72; 95% CI 1.17 - 2.52), those with altered mental state (aOR 5.36; 95% CI 3.21 - 8.92) and those with previous antimicrobial use (aOR 1.88; 95% CI 1.27 - 2.77) had increased odds of in-hospital mortality. Conclusion. The epidemiology of CRE bloodstream infections remained similar compared with the previous surveillance report. Most infections were HA and caused by OXA-48-like carbapenemase-producing K. pneumoniae with no plasmid-mediated colistin resistance. Standard infection control measures should be strengthened.

Antimicrobial Resistance Patterns of Bacterial and Fungal Isolates in COVID-19

Background: The pattern of bacterial infection in coronavirus disease 2019 (COVID-19) patients differ worldwide. Objectives: This study aimed to determine the patterns of bacterial infections and the antibiotic resistance profile by VITEK 2 (bioMérieux, France) in the culture of blood samples from hospitalized patients with COVID-19. Methods: This retrospective descriptive cross-sectional was conducted on a total of 25 patients with critical COVID-19 admitted to Imam Reza Hospital in Mashhad, Iran, during the first three COVID-19 peaks (2019 - 2020). Results: Among Gram-positive bacteria, two strains isolated from Staphylococcus aureus were methicillin-resistant S. aureus at a concentration of > 2 μg/mL. Enterococcus was vancomycin-resistant Enterococcus at a concentration of higher than 4 μg/mL (the minimum inhibitory concentration [MIC] ≥ 32). Among Gram-negative bacteria, three strains of Acinetobacter baumannii complex were extensively drug-resistant. Conclusions: There is evidence of the remarkable increase of various antibiotics’ MIC during the COVID-19 pandemic, which highlights the impact of the use of steroids on the risk of developing antimicrobial resistance during the COVID-19 pandemic.

A Novel Risk Predictive Scoring Model for Predicting Subsequent Infection After Carbapenem-Resistant Gram-Negative Bacteria Colonization in Hematological Malignancy Patients

Background

This study investigated the high-risk factors associated with the increased vulnerability for subsequent clinical CR-GNB infection in carbapenem-resistant Gram-negative bacteria (CR-GNB)-colonized hematological malignancy (HM) patients and built a statistical model to predict subsequent infection.

Method

All adult HM patients with positive rectoanal swabs culture for CR-GNB between January 2018 and June 2020 were prospectively followed to assess for any subsequent CR-GNB infections and to investigate the risk factors and clinical features of subsequent infection.

Results

A total of 392 HM patients were enrolled. Of them, 46.7% developed a subsequent clinical CR-GNB infection, with 42 (10.7%) cases of confirmed infection and 141 (36%) cases of clinically diagnosed infection. Klebsiella pneumoniae was the dominant species. The overall mortality rate of patients colonized and infected with CR-GNB was 8.6% and 43.7%. A multivariate analysis showed that remission induction chemotherapy and the duration of agranulocytosis, mucositis, and hypoalbuminemia were significant predictors of subsequent infection after CR-GNB colonization. According to our novel risk-predictive scoring model, the high-risk group were >3 times more likely to develop a subsequent infection in comparison with the low-risk group.

Conclusion

Our risk-predictive scoring model can early and accurately predict a subsequent CR-GNB infection in HM patients with CR-GNB colonization. The early administration of CR-GNB-targeted empirical therapy in the high-risk group is strongly recommended to decrease their mortality.

Comparison of Antibiotic Susceptibility of Carbapanem-Resistant Enterobactericeae Species with Two Different Panels (Phoenix BD)

Objective: The aim of this study; The aim of this study is to compare the antibiotic susceptibility of carbapanem-resistant Enterobactericeae strains isolated in the microbiology laboratory of our hospital with two different panels and to evaluate the performance of the CPO test. Material & Method: The samples sent to the microbiology laboratory of our hospital between 01.01.2020 - 31.12.2020 were evaluated. Specimens with growth were loaded onto the BD Phoenix 100 automated system BD Phoenix NMIC 433 panel, and 50 isolates of Enterobacteriaceae that resulted in carbapenem resistant were studied with the BD Phoenix NMIC 505 CPO panel. 50 carbapenem-resistant Enterobacteriaceae isolates were classified according to Ambler class A, B, and D by the CPO panel. Results: Of the isolates, 28 (56%) were isolated from male patients and 22 (44%) from female patients. Of the carbapenem-resistant Enterobacteriaceae isolates, 43 (86%) were identified as Klebsiella pneumoniae and 4 (8%) were Escherichia coli. When the evaluation of antibiotic susceptibility rates of the CPO panel and NMIC 433 panel of carbapenem-resistant Enterobacteriaceae isolates were examined; Antibiotic susceptibility results of 50 Enterobacteriaceae isolates studied in both panels were found to be the same. When the antibiotics that can be studied in the CPO panel were examined, it was observed that the most effective antibiotic was ceftazidime-avibactam. When the results were examined, it was observed that 46 (92%) isolates were susceptible to ceftazidime-avibactam. The number of bacteria producing class B carbapenemase was 4 (8%) and the number of bacteria producing class D carbapenemase was 42 (84%). Conclusion: It should be noted that ceftazidime avibactam can be used as a treatment option in carbapenem-resistant species. Further work on the CPO panel will help identify the contribution of the CPO panel to the routine workflow.

Gold-Derived Molecules as New Antimicrobial Agents

Antimicrobial resistance is considered one of the three most important health problems by the World Health Organization. The emergence and spread of an increasing number of antimicrobial-resistant microorganisms make this a worldwide problem. Antibiotic-resistant bacteria are estimated to be the cause of 33,000 deaths in Europe and 700,000 worldwide each year. It is estimated that in 2050 bacterial infections will cause 10 million deaths across the globe. This problem is concomitant with a decrease in the investment and, therefore, the discovery and marketing of new antibiotics. Recently, there have been tremendous efforts to find new effective antimicrobial agents. Gold complexes, with their broad-spectrum antimicrobial activities and unique modes of action, are particularly relevant among several families of derivatives that have been investigated. This mini review revises the role of gold-derived molecules as antibacterial agents.

Global colistin use: A review of the emergence of resistant Enterobacterales and the impact on their genetic basis

The dramatic global rise of MDR and XDR Enterobacterales in human medicine forced clinicians to the reintroduction of colistin as last-resort drug. Meanwhile, colistin is used in the veterinary medicine since its discovery, leading to a steadily increasing prevalence of resistant isolates in the livestock and meat-based food sector. Consequently, transmission of resistant isolates from animals to humans, acquisition via food and exposure to colistin in the clinic are reasons for the increased prevalence of colistin-resistant Enterobacterales in humans in the last decades. Initially, resistance mechanisms were caused by mutations in chromosomal genes. However, since the discovery in 2015, the focus has shifted exclusively to mobile colistin resistances (mcr). This review will advance the understanding of chromosomal-mediated resistance mechanisms in Enterobacterales. We provide an overview about genes involved in colistin resistance and the current global situation of colistin-resistant Enterobacterales. A comparison of the global colistin use in veterinary and human medicine highlights the effort to reduce colistin sales in veterinary medicine under the One Health approach. In contrast, it uncovers the alarming rise in colistin consumption in human medicine due to the emergence of MDR Enterobacterales, which might be an important driver for the increasing emergence of chromosome-mediated colistin resistance.

Antibiotic Resistance Pattern of Extended Spectrum Beta Lactamase Producing Escherichia coli Isolated From Patients With Urinary Tract Infection in Morocco

Extended-spectrum β-lactamases producing Escherichia coli (ESBL-EC) lend resistance to most β-lactam antibiotics. Because of limited treatment options, ESBL-EC infections are generally more difficult to treat, leading to higher hospital costs, reduced rates of microbiological and clinical responses, and a threat to the patient’s life. This study aimed to determine the antibiotic resistance pattern of ESBL-EC isolated from patients with urinary tract infection in Morocco. This retrospective laboratory-based study was conducted at Cheikh Khalifa International University Hospital, Casablanca, from January 2016 to June 2019. A total of 670 urine samples were collected from urinary tract infection patients and processed by standard microbiological methods. In vitro susceptibility testing to different antibiotics of all identified isolates of Escherichia coli (E. coli) was performed following Kirby–Bauer’s disc diffusion method on Mueller–Hinton Agar according to the EUCAST standards. The reviewing of ESBL-EC was confirmed by the appearance of a characteristically shaped zone referred to as a “champagne cork” using the Combined Disk Test. Among a total of 438 E. coli isolated from nonrepetitive urine samples, two hundred fifty-nine (59%) were ESBL-EC, of which 200 (77%) were isolated from adult patients (over the age of 50) and the majority were female. All ESBL-EC isolates were resistant to third-generation cephalosporin and quinolones and sensitive to carbapenem and fosfomycin. Knowledge of antimicrobial resistance patterns in ESBL-EC, the major pathogen associated with urinary tract infection, is indispensable as a guide in choosing empirical antimicrobial treatment.

Activity of imipenem/relebactam against a Spanish nationwide collection of carbapenemase-producing Enterobacterales

BACKGROUND

Imipenem/relebactam is a novel carbapenem/β-lactamase inhibitor combination, developed to act against carbapenemase-producing Enterobacterales (CPE).

OBJECTIVES

To assess the in vitro activity of imipenem/relebactam against a Spanish nationwide collection of CPE by testing the susceptibility of these isolates to 16 widely used antimicrobials and to determine the underlying β-lactam resistance mechanisms involved and the molecular epidemiology of carbapenemases in Spain.

MATERIALS AND METHODS

Clinical CPE isolates (n = 401) collected for 2 months from 24 hospitals in Spain were tested. MIC50, MIC90 and susceptibility/resistance rates were interpreted in accordance with the EUCAST guidelines. β-Lactam resistance mechanisms and molecular epidemiology were characterized by WGS.

RESULTS

For all isolates, high rates of susceptibility to colistin (86.5%; MIC50/90 = 0.12/8 mg/L), imipenem/relebactam (85.8%; MIC50/90 = 0.5/4 mg/L) and ceftazidime/avibactam (83.8%, MIC50/90 = 1/≥256 mg/L) were observed. The subgroups of isolates producing OXA-48-like (n = 305, 75.1%) and KPC-like enzymes (n = 44, 10.8%) were highly susceptible to ceftazidime/avibactam (97.7%, MIC50/90 = 1/2 mg/L) and imipenem/relebactam (100.0%, MIC50/90 = ≤0.25/1 mg/L), respectively.The most widely disseminated high-risk clones of carbapenemase-producing Klebsiella pneumoniae across Spain were found to be ST11, ST147, ST392 and ST15 (mostly associated with OXA-48) and ST258/512 (in all cases producing KPC).

CONCLUSIONS

Imipenem/relebactam, colistin and ceftazidime/avibactam were the most active antimicrobials against all CPEs. Imipenem/relebactam is a valuable addition to the antimicrobial arsenal used in the fight against CPE, particularly against KPC-producing isolates, which in all cases were susceptible to this combination.

Longitudinal analysis of ESBL and carbapenemase carriage among Enterobacterales and Pseudomonas aeruginosa isolates collected in Europe as part of the International Network for Optimal Resistance Monitoring (INFORM) global surveillance programme, 2013-17

OBJECTIVES

To determine the spread of ESBLs and carbapenemases in Enterobacterales and Pseudomonas aeruginosa in Europe.

METHODS

45 335 Gram-negative bacilli were collected in 18 European countries as part of the International Network for Optimal Resistance Monitoring (INFORM) global surveillance programme from 2013 to 2017. Antimicrobial susceptibility was determined using broth microdilution, and 9546 isolates were screened for β-lactamase genes by PCR and sequencing.

RESULTS

ESBLs were identified in 35.5% of Klebsiella pneumoniae and 18.5% of Escherichia coli. ESBL carriage was lowest among isolates in Northern/Western Europe and highest in Eastern Europe. CTX-M-15 was the dominant ESBL in all countries except Greece, where SHV-type ESBLs were more common. Carbapenemases (KPC, OXA-48-like, GES, NDM and VIM) were found in 3.4% of Enterobacterales and were most common among K. pneumoniae (10.5% of those collected). Carbapenemase carriage was lowest in Northern/Western and highest in Southern Europe. KPC-positive Enterobacterales were most abundant but the percentages of OXA-48-like-, NDM- and VIM-positive isolates increased over time and were correlated with an increase in meropenem non-susceptibility. Carbapenemases (VIM, IMP, NDM and GES) were also identified in 5.1% of P. aeruginosa and were commonly found in Eastern Europe. Carbapenemase carriage and meropenem non-susceptibility among P. aeruginosa fluctuated over the 5 years studied and were not well correlated.

CONCLUSIONS

ESBL and carbapenemase carriage varied by species and European subregion. Meropenem non-susceptibility in European isolates of Enterobacterales can be attributed to carbapenemase carriage and is increasingly caused by MBLs and OXA-48-like carbapenemases. Carbapenemases or other β-lactamases are not a common cause of meropenem non-susceptibility in P. aeruginosa in Europe.

Evaluation of the BD Phoenix CPO detect panel for prediction of Ambler class carbapenemases

Rapid detection of carbapenemases as a cause of resistance is beneficial for infection control and antimicrobial therapy. The BD Phoenix NMIC-502 panel and CPO detect test identifies presence of carbapenemases in Enterobacterales such as Klebsiella pneumoniae and assigns them to Ambler classes. To evaluate the performance of the CPO detect panel, we employed a European collection of 1222 K. pneumoniae including carbapenem non-susceptible and susceptible clinical isolates from 26 countries, for which draft genomes were available after Illumina sequencing and the presence of carbapenemase genes had been identified by ARIBA gene calling. The CPO panel detected 488 out of 494 carbapenemase-encoding isolates as positive and six as negative. One-hundred and two isolates were tested positive for carbapenemase in the absence of any carbapenemase gene. The CPO panel identified 229 out of 230 KPC-positive isolates as carbapenemase producing and classified 62 of these as class A enzyme. Similarly, the CPO panel correctly specified 167 of 182 as class D. Regarding metallo-beta-lactamases, the CPO panel assigned 78 of 90 MBL positive isolates to class B enzymes. The sensitivity of the CPO panel in detecting carbapenemase activity was 99.5%, 97.7% and 98.3% for class A, B and D enzymes, respectively. The sensitivity in assignation to Ambler class A, B and D was 27%, 86% and 91%, respectively. An overall sensitivity of 98.8% and specificity of 86% in unclassified detection of carbapenemases was observed, with frequent false positive detection of carbapenemase producing organisms, thus rendering further confirmatory tests necessary.

Epidemiology of Carbapenem Resistance Determinants Identified in Meropenem-Nonsusceptible Enterobacterales Collected as Part of a Global Surveillance Program, 2012 to 2017

To estimate the incidence of carbapenem-resistant Enterobacterales (CRE), a global collection of 81,781 surveillance isolates of Enterobacterales collected from patients in 39 countries in five geographic regions from 2012 to 2017 was studied. Overall, 3.3% of isolates were meropenem-nonsusceptible (MIC ≥2 μg/ml), ranging from 1.4% (North America) to 5.3% (Latin America) of isolates by region. Klebsiella pneumoniae accounted for the largest number of meropenem-nonsusceptible isolates (76.7%). The majority of meropenem-nonsusceptible Enterobacterales carried KPC-type carbapenemases (47.4%), metallo-β-lactamases (MBLs; 20.6%) or OXA-48-like β-lactamases (19.0%). Forty-three carbapenemase sequence variants (8 KPC-type, 4 GES-type, 7 OXA-48-like, 5 NDM-type, 7 IMP-type, and 12 VIM-type) were detected, with KPC-2, KPC-3, OXA-48, NDM-1, IMP-4, and VIM-1 identified as the most common variants of each carbapenemase type. The resistance mechanisms responsible for meropenem-nonsusceptibility varied by region. A total of 67.3% of all carbapenemase-positive isolates identified carried at least one additional plasmid-mediated or intrinsic chromosomally encoded extended-spectrum β-lactamase, AmpC β-lactamase, or carbapenemase. The overall percentage of meropenem-nonsusceptible Enterobacterales increased from 2.7% in 2012 to 2014 to 3.8% in 2015 to 2017. This increase could be attributed to the increasing proportion of carbapenemase-positive isolates that was observed, most notably among isolates carrying NDM-type MBLs in Asia/South Pacific, Europe, and Latin America; OXA-48-like carbapenemases in Europe, Middle East/Africa, and Asia/South Pacific; VIM-type MBLs in Europe; and KPC-type carbapenemases in Latin America. Ongoing CRE surveillance combined with a global antimicrobial stewardship strategy, sensitive clinical laboratory detection methods, and adherence to infection control practices will be needed to interrupt the spread of CRE.

Temporal and regional incidence of carbapenemase-producing Enterobacterales, Switzerland, 2013 to 2018

IntroductionIn contrast to countries where carbapenemase-producing Enterobacterales (CPE) are endemic, only sporadic cases were reported in Switzerland until 2013. An aggravation of the epidemiological situation in neighbouring European countries indicated the need for a surveillance study in Switzerland.AimWe aimed to describe CPE distributions in Switzerland and identify epidemiological factors associated with changes in incidence.MethodsData on all human CPE isolates from 2013 to 2018 were collected by the Swiss Centre for Antibiotic Resistance (ANRESIS) and analysed for temporal and regional trends by Generalised Poisson regression. Isolates associated with infection or colonisation were included in a primary analysis; a secondary analysis included invasive isolates only. Statistical detection of regional clusters was performed with WHONET/SaTScan.ResultsWe analysed 731 CPE isolates, of which 325 (44.5%) were associated with screenings and 173 (23.7%) with infections. Yearly detection of CPE isolates increased considerably during the study period from 65 to 212. The most frequently isolated species were Klebsiella pneumoniae (54%) and Escherichia coli (28%). The most frequent genotypes were OXA-48 (43%), KPC (21%) and NDM (14%). In contrast to the French-speaking parts of Switzerland (West, Geneva) where OXA-48 were the predominant genotypes (around 60%), KPC was the most frequently detected genotype in the Italian-speaking region (63%). WHONET/SaTScan outbreak detection analysis identified seven clusters in five regions of Switzerland.ConclusionsIn a first continuous surveillance of CPE in Switzerland, we found that the epidemiological situation aggravated nationwide and that regional patterns of CPE genotypes mirrored the situation in neighbouring European countries.

Surveillance of Resistance to New Antibiotics in an Era of Limited Treatment Options

As with any health threat, our ability to respond to the emergence and spread of antimicrobial resistance depends on our ability to understand the scale of the problem, magnitude, geographical spread, and trends over time. This is especially true for resistance emergence to newer antibiotics coming to the market as last-resort treatments. Yet current antibiotic surveillance systems are limited to monitoring resistance to commonly prescribed drugs that have been on the market for a long time. This qualitative study determined the essential elements and requirements of antimicrobial resistance surveillance for new antibiotics based on literature review, interviews and expert consensus. After an extensive mapping exercise, 10 experts participated in a modified Delphi consultation to identify consensus on all elements required for surveillance of resistance to novel antibiotics. The main findings indicate that there is a need for a two-phase system; an early alert system transitioning to routine surveillance, led by the public sector to gather and share essential data on resistance to newer antibiotics in a transparent manner. The system should be decentralized, run largely from national level, but be coordinated by an arm of an existing international public health institution. Priority should be given to monitoring emergence of resistance among already multi-drug resistant pathogens causing infections, over a broader selection of pathogens to maximize clinical impact. In conclusion, we cannot rely on current AMR surveillance systems to monitor resistance emergence to new antibiotics. A new, public system should be set-up, starting with a focus on detecting resistance emergence, but expanding to a more comprehensive surveillance as soon as there is regional spread of resistance to the new antibiotic. This article provides a framework based on expert agreement, which could guide future initiatives.

Rapid detection of KPC-producing Enterobacterales by using a modified Carba NP test with imipenem/relebactam

INTRODUCTION

Here, we propose a novel modified Carba NP test for detecting KPC-producing Enterobacterales using imipenem/relebactam.

MATERIAL AND METHODS

The test performance was evaluated in a random selection of 160 previously molecularly characterized clinical isolates carrying the 110 blaKPC, 1 blaGES, 12 blaVIM, 4 blaIMP, 3 blaNDM and 42 blaOXA-48-like genes. The proposed method relies on the detection of imipenem hydrolysis in an imipenem/relebactam antibiotic solution and subsequent visual interpretation by color change.

RESULTS

All class A producing Enterobacterales (111/111) were detected using imipenem/relebactam as no visual appreciation of color change was perceived due to a nule hydrolysis of imipenem in the antibiotic solution. Overall, the assay showed 100% sensitivity (111/111) and specificity (69/69) for detecting class A KPC-producing Enterobacterales.

DISCUSSION

The biochemical assay provides very reliable results for detecting KPC-producing Enterobacterales, with a turnaround time of less than 1 hour, minimum handling and no specialized equipment required.

An Update on Eight "New" Antibiotics against Multidrug-Resistant Gram-Negative Bacteria

Infections in the ICU are often caused by Gram-negative bacteria. When these microorganisms are resistant to third-generation cephalosporines (due to extended-spectrum (ESBL) or AmpC beta-lactamases) or to carbapenems (for example carbapenem producing Enterobacteriales (CPE)), the treatment options become limited. In the last six years, fortunately, there have been new antibiotics approved by the U.S. Food and Drug Administration (FDA) with predominant activities against Gram-negative bacteria. We aimed to review these antibiotics: plazomicin, eravacycline, temocillin, cefiderocol, ceftazidime/avibactam, ceftolozane/tazobactam, meropenem/vaborbactam, and imipenem/relebactam. Temocillin is an antibiotic that was only approved in Belgium and the UK several decades ago. We reviewed the in vitro activities of these new antibiotics, especially against ESBL and CPE microorganisms, potential side effects, and clinical studies in complicated urinary tract infections (cUTI), intra-abdominal infections (cIAI), and hospital-acquired pneumonia/ventilator-associatedpneumonia (HAP/VAP). All of these new antibiotics are active against ESBL, and almost all of them are active against CPE caused by KPC beta-lactamase, but only some of them are active against CPE due to MBL or OXA beta-lactamases. At present, all of these new antibiotics are approved by the U.S. Food and Drug Administration for cUTI (except eravacycline) and most of them for cIAI (eravacycline, ceftazidime/avibactam, ceftolozane/tazobactam, and imipenem/relebactam) and for HAP or VAP (cefiderocol, ceftazidime/avibactam, ceftolozane/tazobactam, and imipenem/relebactam).

National Policy for Carbapenem-Resistant Enterobacteriaceae (CRE) Clearance and Discontinuation of Contact Precautions for CRE Carriers in Post-Acute Care Hospitals in Israel: Impact on Isolation-Days and New Acquisitions

BACKGROUND

In 2009, the Israeli Ministry of Health implemented in post-acute care hospitals (PACHs) a process of discontinuing carbapenem-resistant Enterobacteriaceae (CRE) carrier status. We evaluated the policy's impact on isolation-days, CRE prevalence among known carriers who had completed clearance testing, and CRE acquisition among noncarriers.

METHODS

This retrospective study summarized findings from all 15 PACHs in 2009-2017. CRE carriers were considered cleared and removed from contact isolation after 2 rectal cultures negative for CRE and polymerase chain reaction negative for carbapenemases. Data sources included routine surveillance and 4 point prevalence surveys conducted from 2011 to 2017.

RESULTS

During the study period, 887 of 6101 CRE carriers (14.5%) completed clearance testing. From 2013 to 2016, the percentage of patient-days in CRE isolation decreased from 9.4% to 3.9% (P = .008). In all surveys combined, there were 819 known CRE carriers; 411 (50%) had completed clearance testing. Of these, 11.4% (47/411) were CRE positive in the survey. At the ward level, the median percentage of patients with no CRE history who were positive on survey decreased from 11.3% in 2011 to 0% in 2017 (P < .001). We found no ward-level correlation between the proportion of carriers who completed clearance and new acquisitions (ρ = 0.02, P = .86).

CONCLUSIONS

A process for discontinuing CRE carrier status in PACHs led to a significant reduction in the percentage of patient-days in contact isolation without increasing CRE acquisitions among noncarriers.

Cefiderocol: A Siderophore Cephalosporin

OBJECTIVE

This article reviews the available data on the chemistry, spectrum of activity, pharmacokinetic and pharmacodynamic properties, clinical efficacy, and potential place in therapy of cefiderocol.

DATA SOURCES

A literature search through PubMed, Google Scholar, and ClinicalTrials.gov was conducted (2009 to March 2020) using the search terms cefiderocol and S-649266. Abstracts presented at recent conferences, prescribing information, and information from the US Food and Drug Administration (FDA) and the manufacturer's website were reviewed.

STUDY SELECTION AND DATA EXTRACTION

All relevant published articles, package inserts, and unpublished meeting abstracts on cefiderocol were reviewed.

DATA SYNTHESIS

Cefiderocol is the first siderophore antibiotic to be approved by the FDA. It was shown to be active against a wide range of resistant Gram-negative pathogens, including multidrug-resistant (MDR) Pseudomonas aeruginosa, Acinetobacter baumannii, Enterobacteriaceae, and Stenotrophomonas maltophilia. Cefiderocol was studied in the treatment of adult patients with complicated urinary tract infections (cUTIs) and nosocomial pneumonia and was well tolerated. In a recently completed prospective study, higher mortality was observed with cefiderocol in the treatment of serious infections caused by carbapenem-resistant (CR) Gram-negative pathogens.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

The approval of cefiderocol provides a new option in the treatment of cUTIs and potentially treatment of nosocomial pneumonia caused by resistant Gram-negative pathogens. Given the higher mortality observed with cefiderocol, its use in the treatment of CR Gram-negative infections should be carefully considered.

CONCLUSION

Cefiderocol shows promising activity against MDR Gram-negative pathogens. Its use in the treatment of serious infections caused by CR Gram-negative bacteria needs further evaluation in phase III clinical studies.

Relationship between Virulence and Resistance among Gram-Negative Bacteria

Bacteria present in the human body are innocuous, providing beneficial functions, some of which are necessary for correct body function. However, other bacteria are able to colonize, invade, and cause damage to different tissues, and these are categorised as pathogens. These pathogenic bacteria possess several factors that enable them to be more virulent and cause infection. Bacteria have a great capacity to adapt to different niches and environmental conditions (presence of antibiotics, iron depletion, etc.). Antibiotic pressure has favoured the emergence and spread of antibiotic-resistant bacteria worldwide. Several studies have reported the presence of a relationship (both positive and negative, and both direct and indirect) between antimicrobial resistance and virulence among bacterial pathogens. This review studies the relationship among the most important Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) taking into account two points of view: (i) the effect the acquisition of resistance has on virulence, and (ii) co-selection of resistance and virulence. The relationship between resistance and virulence among bacteria depends on the bacterial species, the specific mechanisms of resistance and virulence, the ecological niche, and the host.

Carbapenemase Producing Enterobacterales in Romania: Investigating the Origins

Carbapenemase-producing Enterobacterales (CPE) have emerged and spread in Romania since 2010. According to the reports of the EuSPACE (European survey of carbapenemase-producing Enterobacteriaceae) the epidemio-logical stage of the CPE expansion in Romania has shifted from sporadic occurrence in 2013 directly to inter-regional spread in 2014-2015. In this study we aimed to provide data from the timeframe when the dissemination of the carbapenemase genes in Romania began, by retrospectively analyzing CPE strains in a tertiary care university hospital. During the period of November 2012 – October 2013 we found 107 CPE (8.78%) out of 1219 non-duplicate Enterobacterales strains. 26 isolates of various Enterobacterales species carried blaNDM-1, 83 Klebsiella pneumoniae strains were positive for blaOXA-48-like and 2 of these co-harboured blaNDM-1. The increased incidence of OXA-48 producing K. pneumoniae was linked to a two-peaked hospital outbreak during February and May 2013. The percentage of 24.3% of NDM-1 producers was alarming due to the diversity of involved species and the higher resistance levels to carbapenems compared with blaOXA-48-like gene carriers. Plasmid replicon typing revealed a great diversity of plasmids in NDM-1-positive strains, belonging to incompatibility groups A/C, FII, FIIk, HI2, L and M. The strong connection between certain plasmid groups and host species suggests that the transfer of broad host-range plasmids through conjugation does not play the main role in the successful spread of blaNDM-1 among Enterobacterales species.

Attributable mortality of antibiotic resistance in gram-negative infections in the Netherlands: a parallel matched cohort study

OBJECTIVES

Antibiotic resistance in Gram-negative bacteria has been associated with increased mortality. This was demonstrated mostly for third-generation cephalosporin-resistant (3GC-R) Enterobacterales bacteraemia in international studies. Yet, the burden of resistance specifically in the Netherlands and created by all types of Gram-negative infection has not been quantified. We therefore investigated the attributable mortality of antibiotic resistance in Gram-negative infections in the Netherlands.

METHODS

In eight hospitals, a sample of Gram-negative infections was identified between 2013 and 2016, and separated into resistant and susceptible infection cohorts. Both cohorts were matched 1:1 to non-infected control patients on hospital, length of stay at infection onset, and age. In this parallel matched cohort set-up, 30-day mortality was compared between infected and non-infected patients. The impact of resistance was then assessed by dividing the two separate risk ratios (RRs) for mortality attributable to Gram-negative infection.

RESULTS

We identified 1954 Gram-negative infections, of which 1190 (61%) involved Escherichia coli, 210 (11%) Pseudomonas aeruginosa, and 758 (39%) bacteraemia. Resistant Gram-negatives caused 243 infections (12%; 189 (78%) 3GC-R Enterobacterales, nine (4%) multidrug-resistant P. aeruginosa, no carbapenemase-producing Enterobacterales). Subsequently, we matched 1941 non-infected controls. After adjustment, point estimates for RRs comparing mortality between infections and controls were similarly higher than 1 in case of resistant infections and susceptible infections (1.42 (95% confidence interval 0.66-3.09) and 1.32 (1.06-1.65), respectively). By dividing these, the RR reflecting attributable mortality of resistance was calculated as 1.08 (0.48-2.41).

CONCLUSIONS

In the Netherlands, antibiotic resistance did not increase 30-day mortality in Gram-negative infections.

Worsening epidemiological situation of carbapenemase-producing Enterobacteriaceae in Europe, assessment by national experts from 37 countries, July 2018

A survey on the epidemiological situation, surveillance and containment activities for carbapenemase-producing Enterobacteriaceae (CPE) was conducted in European countries in 2018. All 37 participating countries reported CPE cases. Since 2015, the epidemiological stage of CPE expansion has increased in 11 countries. Reference laboratory capability, dedicated surveillance and a specific national containment plan are in existence in 33, 27 and 14 countries, respectively. Enhanced control efforts are needed for CPE containment in Europe.

Evaluation of NG-Test Carba 5 for Rapid Phenotypic Detection and Differentiation of Five Common Carbapenemase Families: Results of a Multicenter Clinical Evaluation

NG-Test Carba 5 is a rapid in vitro multiplex immunoassay for the phenotypic detection and differentiation of five common carbapenemase families (KPC, OXA-48-like, VIM, IMP, and NDM) directly from bacterial colonies. The assay is simple to perform and has recently received U.S. Food and Drug Administration clearance. A method comparison study was performed at geographically diverse medical centers (n = 3) in the United States, where 309 Enterobacterales and Pseudomonas aeruginosa isolates were evaluated by NG-Test Carba 5 (NG Biotech, Guipry, France), the Xpert Carba-R assay (Cepheid, Inc., Sunnyvale, CA), the modified carbapenem inactivation method (mCIM), the EDTA-modified carbapenem inactivation method, and disk diffusion with carbapenems. Colonies from tryptic soy agar with 5% sheep blood (blood agar) and MacConkey agar were tested, and the results were compared to those obtained by a composite reference method. Additionally, a fourth medical center performed a medium comparison study by evaluating the performance characteristics of NG-Test Carba 5 from blood, MacConkey, and Mueller-Hinton agars with 110 isolates of Enterobacterales and P. aeruginosa These results were compared to the expected genotypic and mCIM results. For the multicenter method comparison study, the overall positive percent agreement (PPA) and the overall negative percent agreement (NPA) of NG-Test Carba 5 with the composite reference method were 100% for both blood and MacConkey agars. The medium comparison study at the fourth site showed that the PPA ranged from 98.9% to 100% and that the NPA ranged from 95.2% to 100% for blood, MacConkey, and Mueller-Hinton agars. NG-Test Carba 5 accurately detected and differentiated five common carbapenemase families from Enterobacterales and P. aeruginosa colonies on commonly used agar media. The results of this test will support a streamlined laboratory work flow and will expedite therapeutic and infection control decisions.

Early OXA-48-Producing Enterobacterales Isolates Recovered in a Spanish Hospital Reveal a Complex Introduction Dominated by Sequence Type 11 (ST11) and ST405 Klebsiella pneumoniae Clones

Carbapenemase-producing Enterobacterales (CPE) have become an important public health concern. In our hospital, VIM enzymes were first detected in 2005, Klebsiella pneumoniae carbapenemase (KPC) enzymes in 2009, and OXA-48 enzymes in 2012. We assess the population biology of the first OXA-48-producing Enterobacterales isolates recovered in our hospital (2012 to 2013) where infections by other carbapenemases had been endemic for several years. Over a 21-month period, 71 isolates (61 Klebsiella pneumoniae, 5 Escherichia coli, 2 Klebsiella aerogenes, and 1 each of Enterobacter cloacae, Klebsiella oxytoca, and Citrobacter amalonaticus) recovered from clinical and surveillance specimens from 57 patients (22.8% nonhospitalized) were investigated for OXA-48-like-producing enzymes. Analyses for characterization and determination of the location of the bla _OXA-48 gene, plasmid transferability, sequence, and clonal relatedness were performed. Most of the isolates also coproduced CTX-M-15 (57/71, 80.3%) and/or VIM-1 (7/71, 9.8%). K. pneumoniae was predominantly identified as sequence type 11 (ST11) (63.4%) and ST405 (9.8%) and E. coli as ST540, ST1406, ST3163, and ST4301. The bla _OXA-48 gene was part of Tn1999.2 located at the tir gene of plasmids (ca. ≥50 kb) of the IncL/M group, also carrying bla _VIM-1 and bla _CTX-M-15 genes. We selected one ST11 K. pneumoniae isolate for whole-genome sequencing in which we studied the plasmid containing the bla _OXA-48 gene. This plasmid was compared with indexed plasmids existing in NCBI database by the use of BRIG and MAUVE. Our data suggest a rapid spread of bla _OXA-48 genes between commonly isolated high-risk clones of Enterobacterales species, frequently associated with antibiotic resistance. Moreover, the emergence of the multiresistant ST11 K. pneumoniae clone among nonhospitalized patients emphasizes the difficulty of preventing its dissemination into the community.IMPORTANCE We present results of microbiological analysis of the first Enterobacterales isolates that were isolated in 2012 in our institution expressing OXA-48 carbapenemase. This enzyme confers resistance to carbapenems, an important group of antibiotics widely used in the hospitals. OXA-48 carbapenemase is currently present in many parts of the world, but it is found particularly frequently in the Mediterranean area. It was disseminated at the Ramón y Cajal Hospital and found to be associated with a particular Klebsiella pneumoniae strain, so-called high-risk clone ST11, which was previously found in our institution in association with other enzymes such as CTX-M-15, VIM-1, and KPC-3. This clone might have acquired a plasmid harboring the bla _OXA-48 gene. Our results point out the importance of local epidemiology in the dissemination and maintenance of multidrug-resistant bacteria.

Diagnostic performance of the Xpert Carba-R™ assay directly from rectal swabs for active surveillance of carbapenemase-producing organisms in the largest Brazilian University Hospital

BACKGROUND

The global spread of carbapenemase-producing organisms (CPO) has been considered by international health authorities as a critical public health concern. Brazil has a high CPO prevalence according to distinct publications but many routine microbiology laboratories have only phenotypic resources to evaluate this epidemiological situation, which is time-consuming and detects only carbapenem-resistant isolates missing CPO susceptible expressing a slightly decreased susceptibility. New molecular platforms can detect CPO faster but a local evaluation is essential.

AIM

To evaluate the performance of CPO detection direct from rectal swabs with the Xpert Carba-R™ assay (Cepheid, Sunnyvale, CA) in the largest Brazilian University Hospital.

METHODS

A prospective diagnostic accuracy study of CPO was performed with the collection of rectal swabs from patients admitted into the Intensive Care Unit (ICU) and into the Emergency Department (ED) between April and July 2016. The Xpert Carba-R™ assay results were compared with carbapenem-resistant Enterobacterales (CRE) surveillance cultures plus in-house PCR carbapenemase detection (reference method). In case of discordant results between methods, additional tests were performed. The limit of detection (LoD) for the CRE culture and the Xpert Carba-R™ assay were performed with contrived isolates of known carbapenemases genes.

RESULTS

A total of 921 clinical rectal swabs were analyzed being 21% (196/921) from the ICU and 79% (725/921) from the ED. Overall, the Xpert Carba-R™ assay detected 9.9% (91/921) of CPOs being 9.5% (87/921) positive only for bla_KPC and 0.4% (4/921) positive only for bla_NDM. The reference method detected 9.1% (84/921) CPO being 77 (8.4%) bla_KPC, 5 bla_VIM (0.5%) and 2 bla_NDM (0.2%). No IMP or OXA-48 like gene was detected. Overall, twelve samples, 1.3% (10 bla_KPC, 2 bla_NDM) were Xpert Carba-R™ positive but negative by the reference method. Five isolates (0.5%) were positive for bla_VIM only by in-house PCR and confirmed to be bla_VIM-2 by DNA sequencing. The Kappa value, sensitivity, specificity, positive/negative predictive values and accuracy of the Xpert Carba-R™ assay were; 0.893 (95% confidence interval [CI], 0.842-0.944), 94% (86.7-98.0), 98.6% (97.5-99.3), 86.8% (78.1-93.0), 99.4% (98.6-99.8) and 98.2% (97.3-99.1), respectively. The LoD for bla_KPC of the Xpert Carba-R™ assay and the CRE cultures were 10¹ CFU/swab.

CONCLUSION

The Xpert Carba-R™ assay is an accurate test to detect CPO directly from the rectal swabs with significant lower turnaround time (TAT) when compared to the reference method (CRE culture plus in-house PCR). Xpert Carba-R™ may, therefore, be regarded as a good and fast epidemiological tool.

Rapid Detection of KPC-Producing Enterobacterales Susceptible to Imipenem/Relebactam by Using the MALDI-TOF MS MBT STAR-Carba IVD Assay

KPC-producing Enterobacterales represent a serious public health concern. Limited therapeutic options are available for treatment, however, the novel combination of imipenem/relebactam represents a promising alternative. To preserve the activity of this new antibiotic combination, only targeted treatments will be recommended, and rapid tests to detect susceptible bacteria are therefore urgently needed. Here, we propose a MALDI-TOF-based method using the MBT STAR-Carba IVD assay, Bruker Daltonik, to detect KPC-producing Enterobacterales susceptible to imipenem/relebactam in a random selection of 143 clinical isolates previous molecular characterized, carrying 97 bla_KPC, 1 bla_GES, 12bla_VIM, 4bla_IMP, 3bla_NDM, and 26bla_{OXA–48–like}. Species identification was confirmed by MALDI-TOF MS. The molecular characterization of the isolates was performed by the Xpert Carba-R Assay and the results were used as gold standard. Besides, all isolates were submitted to imipenem and imipenem/relebactam microdilution susceptibility testing. The assay showed an overall sensitivity and specificity to detect class A-producing Enterobacterales susceptible to imipenem/relebactam of 98% (96/98) and 93% (42/45), respectively. This MALDI-TOF-based methodology, with a turnaround time of less than 1 h, is a reliable test for detecting imipenem/relebactam activity and its inclusion in routine laboratory screening would facilitate the correct use of this new combination of antimicrobials as a targeted treatment.

Bacteriophages of Klebsiella spp., their diversity and potential therapeutic uses

Klebsiella spp. are commensals of the human microbiota, and a leading cause of opportunistic nosocomial infections. The incidence of multidrug resistant (MDR) strains of Klebsiella pneumoniae causing serious infections is increasing, and Klebsiella oxytoca is an emerging pathogen. Alternative strategies to tackle infections caused by these bacteria are required as strains become resistant to last-resort antibiotics such as colistin. Bacteriophages (phages) are viruses that can infect and kill bacteria. They and their gene products are now being considered as alternatives or adjuncts to antimicrobial therapies. Several in vitro and in vivo studies have shown the potential for lytic phages to combat MDR K. pneumoniae infections. Ready access to cheap sequencing technologies has led to a large increase in the number of genomes available for Klebsiella-infecting phages, with these phages being heterogeneous at the whole-genome level. This review summarizes our current knowledge on phages of Klebsiella spp. and highlights technological and biological issues relevant to the development of phage-based therapies targeting these bacteria.

Consequences Of Long-Term Bacteria's Exposure To Silver Nanoformulations With Different PhysicoChemical Properties

Purpose

Resistance to antibiotics is a major problem of public health. One of the alternative therapies is silver – more and more popular because of nanotechnology development and new possibilities of usage. As a component of colloid, powder, cream, bandages, etc., nanosilver is often recommended to treat the multidrug-resistant pathogens and we can observe its overuse also outside of the clinic where different physicochemical forms of silver nanoformulations (e.g. size, shape, compounds, surface area) are introduced. In this research, we described the consequences of long-term bacteria exposure to silver nanoformulations with different physicochemical properties, including changes in genome and changes of bacterial sensitivity to silver nanoformulations and/or antibiotics. Moreover, the prevalence of exogenous resistance to silver among multidrug-resistant bacteria was determined.

Materials and Methods

Gram-negative and Gram-positive bacteria strains are described as sensitive and multidrug-resistant strains. The sensitivity of the tested bacterial strains to antibiotics was carried out with disc diffusion methods. The sensitivity of bacteria to silver nanoformulations and development of bacterial resistance to silver nanoformulations has been verified via determination of the minimal inhibitory concentrations. The presence of sil genes was verified via PCR reaction and DNA electrophoresis. The genomic and phenotypic changes have been verified via genome sequencing and bioinformatics analysis.

Results

Bacteria after long-term exposure to silver nanoformulations may change their sensitivity to silver forms and/or antibiotics, depending on the physicochemical properties of silver nanoformulations, resulting from phenotypic or genetic changes in the bacterial cell. Finally, adaptants and mutants may become more sensitive or resistant to some antibiotics than wild types.

Conclusion

Application of silver nanoformulations in the case of multiple resistance or multidrug-resistant bacterial infection can enhance or decrease their resistance to antibiotics. The usage of nanosilver in a clinic and outside of the clinic should be determined and should be under strong control. Moreover, each silver nanomaterial should be considered as a separate agent with a potential different mode of antibacterial action.

Spread of Carbapenem-Resistant Klebsiella pneumoniae in Hub and Spoke Connected Health-Care Networks: A Case Study from Italy

The study describes the spread of carbapenem-resistant Klebsiella pneumoniae (CRKP) in a regional healthcare network in Italy. The project included several stages: (1) Establishment of a laboratory-based regional surveillance network, including all the acute care hospitals of the Marches Region (n = 20). (2) Adoption of a shared protocol for the surveillance of Multi-Drug Resistant Organisms (MDROs). Only the first CRKP isolate for each patient has been included in the surveillance in each hospital. The anonymous tracking of patients, and their subsequent microbial records within the hospital network, allowed detection of networks of inter-hospital exchange of CRKP and its comparison with transfer of patients within the hospital network. Pulsed-Field Gel Electrophoresis (PFGE) analysis has been used to study selected isolates belonging to different hospitals. 371,037 admitted patients have been included in the surveillance system. CRKP has shown an overall incidence rate of 41.0 per 100,000 days of stay (95% confidence interval, CI 38.5–43.5/100,000 DOS), a CRKP incidence rate of isolation in blood of 2.46/100,000 days of stay (95% CI 1.89–3.17/100,000 days of stay (DOS) has been registered; significant variability has been registered in facilities providing different levels of care. The network of CRKP patients’ exchange was correlated to that of the healthcare organization, with some inequalities and the identification of bridges in CRKP transfers. More than 73% of isolates were closely related. Patients’ exchange was an important route of spread of antimicrobial resistance, highlighting the pivotal role played by the hub, and selected institution to be used in prioritizing infection control efforts.

The effect of varying multidrug-resistence (MDR) definitions on rates of MDR gram-negative rods

Background

A multitude of definitions determining multidrug resistance (MDR) of Gram-negative organisms exist worldwide. The definitions differ depending on their purpose and on the issueing country or organization. The MDR definitions of the European Centre for Disease Prevention and Control (ECDC) were primarily chosen to harmonize epidemiological surveillance. The German Commission of Hospital Hygiene and Infection Prevention (KRINKO) issued a national guideline which is mainly used to guide infection prevention and control (IPC) measures. The Swiss University Hospital Zurich (UHZ) - in absentia of national guidelines - developed its own definition for IPC purposes. In this study we aimed to determine the effects of different definitions of multidrug-resistance on rates of Gram-negative multidrug-resistant organisms (GN-MDRO).

Methods

MDR definitions of the ECDC, the German KRINKO and the Swiss University Hospital Zurich were applied on a dataset comprising isolates of Escherichia coli, Klebsiella pneumoniae, Enterobacter sp., Pseudomonas aeruginosa, and Acinetobacter baumannii complex. Rates of GN-MDRO were compared and the percentage of patients with a GN-MDRO was calculated.

Results

In total 11'407 isolates from a 35 month period were included. For Enterobacterales and P. aeruginosa, highest MDR-rates resulted from applying the 'ECDC-MDR' definition. 'ECDC-MDR' rates were up to four times higher compared to 'KRINKO-3/4MRGN' rates, and up to six times higher compared to UHZ rates. Lowest rates were observed when applying the 'KRINKO-4MRGN' definitions. Comparing the 'KRINKO-3/4MRGN' with the UHZ definitions did not show uniform trends, but yielded higher rates for E. coli and lower rates for P. aeruginosa. On the patient level, the percentages of GN-MDRO carriers were 2.1, 5.5, 6.6, and 18.2% when applying the 'KRINKO-4MRGN', 'UHZ-MDR', 'KRINKO-3/4MRGN', and the 'ECDC-MDR' definition, respectively.

Conclusions

Different MDR-definitions lead to considerable variation in rates of GN-MDRO. Differences arise from the number of antibiotic categories required to be resistant, the categories and drugs considered relevant, and the antibiotic panel tested. MDR definitions should be chosen carefully depending on their purpose and local resistance rates, as definitions guiding isolation precautions have direct effects on costs and patient care.

Epidemic of carbapenem-resistant Klebsiella pneumoniae in Europe is driven by nosocomial spread

Public health interventions to control the current epidemic of carbapenem-resistant Klebsiella pneumoniae rely on a comprehensive understanding of its emergence and spread over a wide range of geographical scales. We analysed the genome sequences and epidemiological data of >1,700 K. pneumoniae samples isolated from patients in 244 hospitals in 32 countries during the European Survey of Carbapenemase-Producing Enterobacteriaceae. We demonstrate that carbapenemase acquisition is the main cause of carbapenem resistance and that it occurred across diverse phylogenetic backgrounds. However, 477 of 682 (69.9%) carbapenemase-positive isolates are concentrated in four clonal lineages, sequence types 11, 15, 101, 258/512 and their derivatives. Combined analysis of the genetic and geographic distances between isolates with different β-lactam resistance determinants suggests that the propensity of K. pneumoniae to spread in hospital environments correlates with the degree of resistance and that carbapenemase-positive isolates have the highest transmissibility. Indeed, we found that over half of the hospitals that contributed carbapenemase-positive isolates probably experienced within-hospital transmission, and interhospital spread is far more frequent within, rather than between, countries. Finally, we propose a value of 21 for the number of single nucleotide polymorphisms that optimizes the discrimination of hospital clusters and detail the international spread of the successful epidemic lineage, ST258/512.

Antibiotic resistance of Escherichia coli isolated from uncomplicated UTI in general practice patients over a 10-year period

Recommendations of first choice antibiotic therapy need to be based on actual antibiotic susceptibility data. We determined the antibiotic susceptibility of E. coli in uncomplicated UTI among women and compared the results with 2004 and 2009. In 30 sentinel general practitioner practices of Nivel Primary Care database, urine samples were collected from women with symptoms of uncomplicated UTI. Patient characteristics, E. coli susceptibility, and ESBL production were analyzed. Six hundred eighty-nine urine samples were collected; E. coli was the most isolated uropathogen (83%). Antibiotic susceptibility was stable over time except for ciprofloxacin (96% in 2004, 97% in 2009, and 94% in 2014; P < 0.05). The susceptibility to co-amoxiclav was 88%, 87%, and 92% in 2004, 2009, and 2014, respectively. The prevalence of ESBL-producing E. coli increased from 0.1% in 2004 to 2.2% in 2014 (P < 0.05). Regional differences in antibiotic susceptibility for co-trimoxazole were found being the highest in the west (88%) and the lowest in the north (72%, P = 0.021). Ciprofloxacin susceptibility was related to antibiotic use in the past 3 months (97% no use versus 90% use, P = 0.002) and age > 70 years (P = 0.005). In 2014, prescription of fosfomycin increased compared to 2009 (14.3% versus 5.6%) at the expense of co-amoxiclav, co-trimoxazole, and fluoroquinolones (P < 0.05). The susceptibility percentages to most antimicrobial agents tested were stable over 10 years’ period although the prevalence of E. coli and ESBLs significantly increased. Performance of a survey with regular intervals is warranted.

Carbapenemases in Enterobacteriaceae: Detection and Antimicrobial Therapy

Carbapenem-resistant Enterobacteriaceae (CRE) have spread rapidly around the world in the past few years, posing great challenges to human health. The plasmid-mediated horizontal transmission of carbapenem-resistance genes is the main cause of the surge in the prevalence of CRE. Therefore, the timely and accurate detection of CRE, especially carbapenemase-producing Enterobacteriaceae, is very important for the clinical prevention and treatment of these infections. A variety of methods for the rapid detection of CRE phenotypes and genotypes have been developed for use in clinical microbiology laboratories. To overcome the lack of efficient antibiotics, CRE infections are often treated with combination therapies. Moreover, novel drugs and emerging strategies appeared successively and in various stages of development. In this article, we summarized the global distribution of various carbapenemases. And we focused on summarizing and comparing the advantages and limitations of the detection methods and the therapeutic strategies of CRE primarily.

A PCR-based diagnostic testing strategy to identify carbapenemase-producing Enterobacteriaceae carriers upon admission to UK hospitals: early economic modelling to assess costs and consequences

BACKGROUND

Carbapenemase-producing Enterobacteriaceae (CPE), bacteria which are resistant to the carbapenem class of antibiotics, present an urgent public health risk. The objective of this study was to assess the potential costs and consequences of implementing a testing strategy involving a polymerase chain reaction (PCR)-based diagnostic test for CPE amongst high risk patients upon admission to UK hospitals, to replace the current culture-based testing strategy.

METHODS

A decision-analytic model was developed to estimate the expected medical care costs associated with a PCR testing strategy for CPE compared with the current culture testing strategy, and to consider the consequences, in terms of the diagnostic accuracy and associated cost implications, of each approach. The modelled population were patients admitted to hospital at high risk of colonisation with CPE, with model pathways for current practice based on those described in the Public Health England (PHE) toolkit for CPE testing. Costs were estimated from a UK National Health Service (NHS) perspective, with outcomes presented in terms of percentage of samples identified as true positive, false positive, true negative and false negative following each method of testing.

RESULTS

Results indicated that the PCR testing strategy led to an estimated cost saving of £462 per patient for a 5-day hospital stay. For all sensitivity analyses conducted, PCR testing resulted in an expected cost saving. Potential cost savings approached £850 per patient for the sensitivity analysis assuming a 15-day hospital stay, indicating that PCR testing results in greater cost savings as length of stay increases. Fewer false positive, and more true negative, cases were identified with the PCR testing strategy in all analyses conducted.

CONCLUSIONS

This economic analysis gives an insight into the potential cost savings that could be made by the UK NHS through the introduction of a PCR-based diagnostic testing strategy to replace current recommended culture-based methods for the detection of CPE. Savings are due primarily to a faster time to result with PCR, meaning that CPE-free patients are not isolated unnecessarily. Therefore, a PCR-based diagnostic may aid appropriate use of isolation resource.

Treatment of infections caused by multidrug-resistant Gram-negative bacteria: report of the British Society for Antimicrobial Chemotherapy/Healthcare Infection Society/British Infection Association Joint Working Party

The Working Party makes more than 100 tabulated recommendations in antimicrobial prescribing for the treatment of infections caused by multidrug-resistant (MDR) Gram-negative bacteria (GNB) and suggest further research, and algorithms for hospital and community antimicrobial usage in urinary infection. The international definition of MDR is complex, unsatisfactory and hinders the setting and monitoring of improvement programmes. We give a new definition of multiresistance. The background information on the mechanisms, global spread and UK prevalence of antibiotic prescribing and resistance has been systematically reviewed. The treatment options available in hospitals using intravenous antibiotics and in primary care using oral agents have been reviewed, ending with a consideration of antibiotic stewardship and recommendations. The guidance has been derived from current peer-reviewed publications and expert opinion with open consultation. Methods for systematic review were NICE compliant and in accordance with the SIGN 50 Handbook; critical appraisal was applied using AGREE II. Published guidelines were used as part of the evidence base and to support expert consensus. The guidance includes recommendations for stakeholders (including prescribers) and antibiotic-specific recommendations. The clinical efficacy of different agents is critically reviewed. We found there are very few good-quality comparative randomized clinical trials to support treatment regimens, particularly for licensed older agents. Susceptibility testing of MDR GNB causing infection to guide treatment needs critical enhancements. Meropenem- or imipenem-resistant Enterobacteriaceae should have their carbapenem MICs tested urgently, and any carbapenemase class should be identified: mandatory reporting of these isolates from all anatomical sites and specimens would improve risk assessments. Broth microdilution methods should be adopted for colistin susceptibility testing. Antimicrobial stewardship programmes should be instituted in all care settings, based on resistance rates and audit of compliance with guidelines, but should be augmented by improved surveillance of outcome in Gram-negative bacteraemia, and feedback to prescribers. Local and national surveillance of antibiotic use, resistance and outcomes should be supported and antibiotic prescribing guidelines should be informed by these data. The diagnosis and treatment of both presumptive and confirmed cases of infection by GNB should be improved. This guidance, with infection control to arrest increases in MDR, should be used to improve the outcome of infections with such strains. Anticipated users include medical, scientific, nursing, antimicrobial pharmacy and paramedical staff where they can be adapted for local use.