Emergence Of Carbapenemase-producing Enterobacteriaceae Research Articles

Comparing the transmission of carbapenemase-producing and extended-spectrum beta-lactamase-producing Escherichia coli between broiler chickens.

The emergence of carbapenemase-producing Enterobacteriaceae (CPE) is a threat to public health, because of their resistance to clinically important carbapenem antibiotics. The emergence of CPE in meat-producing animals is particularly worrying because consumption of meat contaminated with resistant bacteria comparable to CPE, such as extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae, contributed to colonization in humans worldwide. Currently, no data on the transmission of CPE in livestock is available. We performed a transmission experiment to quantify the transmission of CPE between broilers to fill this knowledge gap and to compare the transmission rates of CPE and other antibiotic-resistant E. coli. A total of 180 Ross 308 broiler chickens were distributed over 12 pens on the day of hatch (day 0). On day 5, half of the 10 remaining chickens in each pen were orally inoculated with 5·102 colony-forming units of CPE, ESBL, or chloramphenicol-resistant E. coli (catA1). To evaluate the effect of antibiotic treatment, amoxicillin was given twice daily in drinking water in 6 of the 12 pens from days 2-6. Cloacal swabs of all animals were taken to determine the number of infectious broilers. We used a Bayesian hierarchical model to quantify the transmission of the E. coli strains. E. coli can survive in the environment and serve as a reservoir. Therefore, the susceptible-infectious transmission model was adapted to account for the transmission of resistant bacteria from the environment. In addition, the caecal microbiome was analyzed on day 5 and at the end of the experiment on day 14 to assess the relationship between the caecal microbiome and the transmission rates. The transmission rates of CPE were 52 - 68 per cent lower compared to ESBL and catA1, but it is not clear if these differences were caused by differences between the resistance genes or by other differences between the E. coli strains. Differences between the groups in transmission rates and microbiome diversity did not correspond to each other, indicating that differences in transmission rates were probably not caused by major differences in the community structure in the caecal microbiome. Amoxicillin treatment from day 2-6 increased the transmission rate more than three-fold in all inoculums. It also increased alpha-diversity compared to untreated animals on day 5, but not on day 14, suggesting only a temporary effect. Future research could incorporate more complex transmission models with different species of resistant bacteria into the Bayesian hierarchical model.

Phenotypic and genotypic characterization of clinical carbapenem-resistant Enterobacteriaceae isolates from Sokoto, northwest Nigeria.

Emergence and spread of carbapenemase-producing Enterobacteriaceae (CPE) are two of the major problems currently threatening global public health. In Nigeria, interest in CPE is recent. In Sokoto, northwest Nigeria, there are no data on the prevalence and mechanism underlying carbapenem resistance. In this study, we aimed to investigate the presence of clinical carbapenems-resistant Enterobacteriaceae isolates in two leading hospitals in Sokoto, northwest Nigeria. A total of 292 non-duplicate Enterobacteriaceae isolated from clinical specimens processed in the diagnostic laboratories of two hospitals between January and June 2019 were collected. Of these, 129 (44.2 %) and 19 (6.5%) were resistant to third-generation cephalosporin and carbapenems, respectively. RT-PCR revealed that 10 (7.8%), 19 (14.7%) and 46 (35.7%) of the third-generation cephalosporin-resistant isolates harboured blaSHV, blaTEM and blaCTX-M genes, respectively. The modified Carba NP test result showed that only 7 (36.8 %) of the 19 carbapenem-resistant isolates were carbapenemase producing; among them, blaNDM-5 and blaOXA-181 genes were identified in five and two isolates, respectively. However, none of the carbapenemase genes investigated, including blaVIM, blaKPC and blaIMP, was detected in the remaining carbapenem-resistant isolates, suggesting a non-enzymatic mechanism. This study reports for the first time, the emergence of CPE in Sokoto state and the detection of NDM-producing Citrobacter freundii in Nigeria. The observed CPE in this study is a concern in a country where alternative antibiotics are rarely available.

Rapid detection and discrimination of chromosome- and MCR-plasmid-mediated resistance to polymyxins by MALDI-TOF MS in Escherichia coli: the MALDIxin test.

Polymyxins are currently considered a last-resort treatment for infections caused by MDR Gram-negative bacteria. Recently, the emergence of carbapenemase-producing Enterobacteriaceae has accelerated the use of polymyxins in the clinic, resulting in an increase in polymyxin-resistant bacteria. Polymyxin resistance arises through modification of lipid A, such as the addition of phosphoethanolamine (pETN). The underlying mechanisms involve numerous chromosome-encoded genes or, more worryingly, a plasmid-encoded pETN transferase named MCR. Currently, detection of polymyxin resistance is difficult and time consuming. To develop a rapid diagnostic test that can identify polymyxin resistance and at the same time differentiate between chromosome- and plasmid-encoded resistances. We developed a MALDI-TOF MS-based method, named the MALDIxin test, which allows the detection of polymyxin resistance-related modifications to lipid A (i.e. pETN addition), on intact bacteria, in <15 min. Using a characterized collection of polymyxin-susceptible and -resistant Escherichia coli, we demonstrated that our method is able to identify polymyxin-resistant isolates in 15 min whilst simultaneously discriminating between chromosome- and plasmid-encoded resistance. We validated the MALDIxin test on different media, using fresh and aged colonies and show that it successfully detects all MCR-1 producers in a blindly analysed set of carbapenemase-producing E. coli strains. The MALDIxin test is an accurate, rapid, cost-effective and scalable method that represents a major advance in the diagnosis of polymyxin resistance by directly assessing lipid A modifications in intact bacteria.

Emergence of NDM-5-producing Escherichia coli sequence type 167 clone in Italy

The emergence of carbapenemase-producing Enterobacteriaceae (CPE) is a critical concern worldwide. In Italy, CPE isolates are very frequent, with the KPC enzyme types strongly predominant whereas the New Delhi metallo-β-lactamase (NDM) enzymes are extremely rare. Here we report the first detection of NDM-5-producing Escherichia coli sequence type 167 (ST167) isolates from two patients with urinary tract infection (Ec001 and Ec002 from urines), including one with colonisation (Ec003 from faeces) admitted to the same hospital 2 months apart in 2017. Minimum inhibitory concentrations (MICs) were determined by broth microdilution. The carbapenemase type was identified both by phenotypic and genotypic methods. Isolate genotypes were investigated by phylogenetic typing, multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). Next-generation sequencing (NGS) was used to obtain complete sequences of plasmids. The three E. coli isolates carried the blaNDM-5 gene, shared the same resistance phenotype and belonged to ST167. By PFGE, isolates showed the same profile, suggesting that they were the same strain. NGS revealed that the blaNDM-5 gene was located on a 99-kb multireplicon plasmid (designed pNDM-5-IT) with a peculiar scaffold constituted by four replicons of the IncF type (FIA, FIB and two copies of the FII replicon). pNDM-5-IT plasmid harboured multiple resistance and virulence determinants, including the arginine deaminase (ADI) cluster never found associated with plasmids before. Since NDM-5-producing E. coli ST167 has been regarded as a successful epidemic clone in China, the emergence of such a clone carrying a plasmid associated both with multiresistance and virulence could be a public-health threat.

Migratory White Stork (Ciconia ciconia): A Potential Vector of the OXA-48-Producing Escherichia coli ST38 Clone in Algeria.

The emergence of carbapenemase-producing Enterobacteriaceae is of great concern to public health worldwide. The aim of this study was to screen for the presence of carbapenemase-producing Enterobacteriaceae in white stork (Ciconia ciconia) migratory bird stools, and to investigate their molecular support on β-lactamase production. In March 2015, 32 fecal samples of white stork were collected in the Commune of El Madher Wilaya de Batna, in eastern Algeria. Samples were subjected to selective isolation of carbapenem-resistant Enterobacteriaceae. Representative colonies were screened phenotypically for carbapenemase production. Carbapenemase-producing isolates were subjected to antibiotic susceptibility testing and extended-spectrum β-lactamase (ESBL) coproduction. β-Lactamase determinants were searched for by PCR and sequencing. Three carbapenemase-producing Escherichia coli were obtained. Only one strain was positive for ESBL production. The OXA-48-type carbapenemase-encoding gene was detected in all isolates. Screening for other β-lactamase-encoding genes showed that all isolates coexpress the blaTEM gene, whereas one of them additionally harbored the blaCTX-M-15 ESBL gene. Multilocus sequence typing results showed that two strains belonged to the sequence type 38. This work demonstrated for the first time that the migratory white stork can play an important role in the dissemination of OXA-48-producing E. coli as a potential reservoir and vector.

The Efficacy of the MicroScan®Walkaway System in Reporting Carbapenemase-Producing Enterobacteriaceae in Patients with Bacteremia, South Africa

Background: The emergence of Carbapenemase-producing Enterobacteriaceae (CPE) is a major public health problem worldwide. As Carbapenemase-production has emerged, treatment of infections has become more difficult leading to high mortality. Real time detection of the presence of these enzymes by in vitro susceptibility testing of these organisms is urgently needed to provide effective treatment and appropriate implementation of infection and prevention control measures. Automated phenotypic systems are widely used in clinical microbiology laboratories for bacterial identification and antimicrobial susceptibility testing. However, critical evaluation is needed to determine the accuracy of these systems. Objective: Our study was set out to evaluate whether the MicroScan® Walkaway system is a reliable method for predicting CPE in patients with a Carbapenem-resistant Enterobacteriaceae (CRE) infections. Methods: This was a cross-sectional study of CRE isolates from July 2015 to July 2016 received as part of an active CRE surveillance programme. Bacterial identification and antimicrobial susceptibility testing for Carbapenems were performed using the MALDI-ToF and MicroScan® Walkaway system, respectively. Genotypic testing was performed using the LightMix® modular Carbapenemase kits in a multiplex real-time PCR assay to confirm the presence of Carbapenemase genes. Results: During the study period, there were 219 CRE tested. Out of 219 CRE cases, Carbapenemase genes were detected in 173 (78.9%). The most prevalent gene was blaNDM (38.8%; n=85), followed by blaOXA-48 and variants (32.8%; n=72), blaVIM (6.9%; n=15) and blaGES (0.5%; n=1). The MicroScan® Walkaway system had the highest sensitivity with ertapenem (86.7%). Sensitivities for all other Carbapenems were similar, but below 65%. The positive predictive value for ertapenem was 78.9% and >80% for imipenem (86.2%), meropenem (81.3%) and doripenem (83.7%). Overall, testing for all Carbapenems had a sensitivity of 89%, positive predictive value of 79% and specificity of 10.9%, amongst them imipenem having the highest specificity at 60.9%. Conclusion: The MicroScan® Walkaway system is sensitive, but lacks specificity. However, it shows to be an efficient diagnostic adjunct to the LightMix® modular multiplex real-time PCR assay for predicting CPE in a patient with a CRE infection depending on the Carbapenem used.

Prevalence and Molecular Characteristics of Carbapenemase-Producing Enterobacteriaceae From Five Hospitals in Korea

BackgroundThe emergence of carbapenemase-producing Enterobacteriaceae (CPE) represents a major clinical problem because these bacteria are resistant to most antibiotics. CPE remain relatively uncommon in Korea. We report the prevalence, clinical characteristics, and molecular epidemiology of CPE isolates collected from five university hospitals in Korea.MethodsBetween January and December 2015, 393 non-duplicated isolates that were nonsusceptible to ertapenem were analyzed. Production of carbapenemase, extended-spectrum β-lactamase, and AmpC β-lactamase was determined by genotypic tests. Antimicrobial susceptibility profiles were determined by using an Etest. Clonality of Klebsiella pneumoniae carbapenemase (KPC)-2-producing and oxacillinase (OXA)-232-producing Klebsiella pneumoniae isolates was determined by pulsed-field gel electrophoresis (PFGE).ResultsOf the 393 isolates tested, 79 (20.1%) were CPE. Of these 79 isolates, 47 (59.5%) harbored the blaOXA-232 gene while the remaining isolates carried genes blaKPC-2 (n=27), blaIMP-1 (n=4), and blaNDM-1 (n=1). Among the 24 KPC-2 K. pneumoniae isolates from hospital B, 100% were resistant to carbapenems, 8% to colistin, and 0% to tigecycline. Among the 45 OXA-232 K. pneumoniae at hospital C, 95% were resistant to ertapenem, 68% to imipenem, 95% to meropenem, 10% to colistin, and 24% to tigecycline. PFGE analysis revealed a unique pattern for KPC-2 K. pneumoniae and identified 30 isolates belonging to the dominant pulsotypes (PT)1 and PT2 among 41 OXA-232 K. pneumoniae isolates.ConclusionsCPE strains are present in Korea, with the majority of K. pneumoniae isolates producing OXA-232 and KPC-2. The prevalence and predominant genotypes of CPE show hospital-specific differences.

Evolution of carbapenemase-producing Enterobacteriaceae at the global and national level: What should be expected in the future?

In recent years, Enterobacteriaceae isolates have increased their potential to become highly drug resistant by acquiring resistance to carbapenems, primarily due to the production of acquired carbapenemases. The carbapenemases detected in Enterobacteriaceae are largely of the KPC, VIM, NDM, IMP and OXA-48 types. Although the epidemiological origin and geographic distribution of carbapenemases are clearly different, they all first appeared in the late 20th Century. Only a decade later, these enzymes have already become established and have expanded globally.An important epidemiological change has occurred in Spain in recent years, characterized by a rapid increase in the number of cases of carbapenemase-producing Enterobacteriaceae (CPE), causing both nosocomial outbreaks and single infections. The impact of CPE in Spain is primarily due to OXA-48-producing and VIM-1-producing Klebsiella pneumoniae isolates, although other species such as Escherichia coli and Enterobacter cloacae are also increasing.The emergence of CPE as a cause of community-onset infections is a matter of great concern. Taking into account recent experience, and considering the fact that increasing numbers of patients are becoming infected by CPE and reservoirs of carbapenemases are growing globally, the trend of the CPE epidemic points toward a rise in its incidence.To prevent a massive CPE pandemic, a well-coordinated response from all health professionals and national and supranational authorities is clearly needed.

Doctoral and post-doctoral research - a priority of the Romanian postgraduate education system.

November 12th 2014: the opening conference for the project “Doctoral and post-doctoral research – a priority of the Romanian postgraduate education system (Doc-Postdoc)” took place in Bucharest, Romania. The project aims to support doctoral and post-doctoral research in Romania, and is cofinanced by the European Social Fund through the Sectoral Operational Programme for Human Resources Development 2007-2013; priority axis 1. “Education and training in support for growth and development of a knowledge based society“; key area of intervention: 1.5. “Doctoral and post-doctoral programs in support of research”; contract code: POSDRU/159/1.5/S/137390. The Carol Davila University of Medicine and Pharmacy in Bucharest is the project beneficiary, partnering with two other major universities in Romania: The University “Politehnica” of Bucharest, and the University of Medicine and Pharmacy Târgu Mures. The conference presented the aims and objectives of the project, but it was also packed with scientific sessions where young PhD candidates and post-doctoral researchers had the opportunity to present the studies they are conducting within this project. The topics discussed spanned through the interdisciplinary fields of biomedicine and bioengineering. Of particular interest to the readers of the Journal GERMS, Dr. Catalin Tiliscan presented data on adipocyte dysfunction in HIV-positive patients undergoing antiretroviral therapy, his study showing that almost half of patients had hyporesistinemia, and resistin was correlated with the inflammatory profile. Also, an unfavorable immune status appeared to be inversely proportional to the values of monocyte chemoattractant protein-1 MCP-1, while leptin values were not correlated with CD4 cell count or virologic status, but rather with HDL-cholesterol and waist circumference. Dr. Ramona Popescu presented an interdisciplinary study protocol for determining the incidence of intercurrent and opportunistic infections in rheumatologic patients undergoing treatment with biologic agents. Dr. Oana Sandulescu presented the preliminary results of a study aimed to determine the capacity of staphylococcal species to adhere to and internalize in eukaryotic cells. By comparing two different types of bacterial strains, collected from patients with clinically-relevant infections and from asymptomatic nasal carriage, the study showed that despite a similar rate of internalization, staphylococci from the two groups displayed statistically significant differences regarding intracellular growth after internalization. Dr. Daniela Talapan presented significant data on the emergence of carbapenemase-producing Enterobacteriaceae, with Klebsiella spp. ranking first among bacteria with resistance to carbapenems, followed by E. coli, E. cloacae, and E. aerogenes, leaving a considerably low number of active antibiotics in play, namely colistin, tigecycline and fosfomycin. Based on the preliminary data presented at the conference, the research conducted within this project is bound to generate information with a significant clinical impact, leading to a better understanding of medical issues currently understudied, with the potential to reshape clinical practice.

Emergence of Klebsiella pneumoniae co-producing NDM-type and OXA-181 carbapenemases

The emergence of carbapenemase-producing Enterobacteriaceae is a rapidly evolving threat worldwide. Here, we report the molecular characterization of two Klebsiella pneumoniae isolates carrying both blaOXA-181 and blaNDM-1 or blaNDM-5 isolated from epidemiologically unrelated patients in Singapore. The blaOXA-181 genes were found existing in different genetic environments.

Emergence of carbapenemase-producing Enterobacteriaceae in France, 2004 to 2011

Emergence of carbapenemase-producing Enterobacteriaceae (CPE) is currently a major public health concern worldwide. This study showed that 53 episodes of CPE infection or colonisation have been notified by French healthcare facilities since 2004. A sharp increase in the number of notifications was observed in the last three years. Oxacillinase (OXA)-48 and Klebsiella pneumoniae carbapenemase (KPC) beta-lactamases were the most frequent enzymes reported in these episodes. The index cases in most episodes were patients with a history of hospitalisation abroad within the previous year. Around a third of the episodes (n=18) led to secondary transmission in hospitals but most of them were controlled due to reinforced measures. Reinforcement of screening and control measures at national level when there is cross-border transfer of patients, along with overall reinforcement of infection control and antimicrobial stewardship worldwide, is urgently needed to contain the spread of CPE.