Occurrence and mechanisms of tigecycline resistance in carbapenem- and colistin-resistant Klebsiella pneumoniae in Thailand

Tigecycline has been regarded as one of the most important last-resort antibiotics for the treatment of infections caused by extensively drug-resistant (XDR) bacteria, particularly carbapenem- and colistin-resistant Klebsiella pneumoniae (C-C-RKP). However, reports on tigecycline resistance have been growing. Overall, ~ 4000 K. pneumoniae clinical isolates were collected over a five-year period (2017-2021), in which 240 isolates of C-C-RKP were investigated. Most of these isolates (91.7%) were resistant to tigecycline. Notably, a high-risk clone of ST16 was predominantly identified, which was associated with the co-harboring of blaNDM-1 and blaOXA-232 genes. Their major mechanism of tigecycline resistance was the overexpression of efflux pump acrB gene and its regulator RamA, which was caused by mutations in RamR (M184V, Y59C, I141T, A28T, C99/C100 insertion), in RamR binding site (PI) of ramA gene (C139T), in MarR (S82G), and/or in AcrR (L154R, R13Q). Interestingly, four isolates of ST147 carried the mutated tet(A) efflux pump gene. To our knowledge, this is the first report on the prevalence and mechanisms of tigecycline resistance in C-C-RKP isolated from Thailand. The high incidence of tigecycline resistance observed among C-C-RKP in this study reflects an ongoing evolution of XDR bacteria against the last-resort antibiotics, which demands urgent action.

Molecular characteristics and antimicrobial resistance profiles of Carbapenem-Resistant Klebsiella pneumoniae isolates at a tertiary hospital in Nanning, China

PURPOSE

Carbapenem resistant Klebsiella pneumoniae is associated with nosocomial infections and can cause high mortality, which poses great threat to human health. This study was aimed at investigating the molecular epidemiology and antimicrobial resistance profiles of carbapenem resistant Klebsiella pneumoniae isolates and providing clues for management and control of carbapenem resistant Klebsiella pneumoniae infections.

METHODS

A total of 2324 Klebsiella pneumoniae strains were isolated from the First Affiliated Hospital of Guangxi Medical University from June 2018 to October 2020, and 103 carbapenem resistant Klebsiella pneumoniae strains from inpatients were collected, and the specimens mainly came from the sputum, urine, secretions, and blood. The antimicrobial susceptibility tests were performed using the VITEK 2 Compact system or the Kirby-Bauer disk-diffusion method. The resistance genes were detected by polymerase chain reaction and sequencing. The homology analysis of carbapenem resistant Klebsiella pneumoniae strains was performed by multilocus sequence typing.

RESULTS

Antimicrobial susceptibility results showed that the 103 carbapenem resistant Klebsiella pneumoniae strains were resistant to most common antibiotics. Resistance genes detection showed that the carbapenem resistant Klebsiella pneumoniae isolates mainly carried metallo-beta-lactamase, and the predominant gene was NDM-1. The homology analysis found that the major ST type were ST11, follow by ST15 and ST17.

CONCLUSION

The carbapenem resistant Klebsiella pneumoniae isolates in our study shown resistance to most common antibiotics. Of the 103 carbapenem resistant Klebsiella pneumoniae strains, 91 strains (88.35%) carried carbapenemases genes, and NDM was the predominant carbapenemase gene detected. ST11 was the major ST typing of carbapenem resistant Klebsiella pneumoniae in our hospital. Our finding may play a role in control and management of the carbapenem resistant Klebsiella pneumoniae infections and guiding clinical antibiotic therapy. In addition, metallo-beta-lactamase should be served as a key target to be monitored in carbapenem resistant Klebsiella pneumoniae infection.

Nutritional analysis and characterization of carbapenemase producing-Klebsiella pneumoniae resistant genes associated with bovine mastitis infected cow's milk

The current study was designed to analyze nutritional parameters and to characterize carbapenemase producing-Klebsiella pneumoniae isolates from bovine mastitic cow's milk. Out of 700 milk samples K. pneumoniae was identified by phenotypic and molecular techniques along with their antibiogram analysis and nutritional analysis was performed using the procedure of Association of Official Analytical Chemists. Carbapenemase-producing K. pneumoniae was detected by phenotypic CarbaNP test followed by molecular characterization of their associated resistant genes blaVIM, blaKPC, blaOXA-48, blaNDM, and blaIMP along with insertion sequence common region 1 (ISCR1) and integrons (Int1, Int2, and Int3) genes. Among nutritional parameters, fat content was observed (2.99%) followed by protein (2.78%), lactose (4.32%), and total solid (11.34%), respectively. The prevalence of K. pneumoniae among bovine mastitis was found 25.71%. Antibiogram analysis revealed that more effective antibiotics was ceftazidime (80%) followed by amikacin (72%), while highly resistant antibiotics was Fusidic acid (100%). Distribution of carbapenemase producer K. pneumoniae was found 44.4%. Among carbapenem resistant genes blaKPC was found 11.25%, blaVIM 2.75%, blaNDM 17.5%, and blaOXA-48 7.5%, while blaIMP gene was not detected. Furthermore, distribution of ISCR1 was found 40%, while integron 1 was found 61.2% followed by integron 2 (20%), and integron 3 (5%). In conclusion, the recent scenario of carbapenemase resistant K. pneumoniae isolates responsible for mastitis may affect not only the current treatment regime but also possess a serious threat to public health due to its food borne transmission and zoonotic potential.

Characteristics and genomic epidemiology of colistin-resistant Enterobacterales from farmers, swine, and hospitalized patients in Thailand, 2014-2017

BACKGROUND

Colistin is one of the last resort therapeutic options for treating carbapenemase-producing Enterobacterales, which are resistant to a broad range of beta-lactam antibiotics. However, the increased use of colistin in clinical and livestock farming settings in Thailand and China, has led to the inevitable emergence of colistin resistance. To better understand the rise of colistin-resistant strains in each of these settings, we characterized colistin-resistant Enterobacterales isolated from farmers, swine, and hospitalized patients in Thailand.

METHODS

Enterobacterales were isolated from 149 stool samples or rectal swabs collected from farmers, pigs, and hospitalized patients in Thailand between November 2014-December 2017. Confirmed colistin-resistant isolates were sequenced. Genomic analyses included species identification, multilocus sequence typing, and detection of antimicrobial resistance determinants and plasmids.

RESULTS

The overall colistin-resistant Enterobacterales colonization rate was 26.2% (n = 39/149). The plasmid-mediated colistin-resistance gene (mcr) was detected in all 25 Escherichia coli isolates and 9 of 14 (64.3%) Klebsiella spp. isolates. Five novel mcr allelic variants were also identified: mcr-2.3, mcr-3.21, mcr-3.22, mcr-3.23, and mcr-3.24, that were only detected in E. coli and Klebsiella spp. isolates from farmed pigs.

CONCLUSION

Our data confirmed the presence of colistin-resistance genes in combination with extended spectrum beta-lactamase genes in bacterial isolates from farmers, swine, and patients in Thailand. Differences between the colistin-resistance mechanisms of Escherichia coli and Klebsiella pneumoniae in hospitalized patients were observed, as expected. Additionally, we identified mobile colistin-resistance mcr-1.1 genes from swine and patient isolates belonging to plasmids of the same incompatibility group. This supported the possibility that horizontal transmission of bacterial strains or plasmid-mediated colistin-resistance genes occurs between humans and swine.

Molecular surveillance reveals the emergence and dissemination of NDM-5-producing Escherichia coli high-risk clones in Germany, 2013 to 2019

BackgroundCarbapenemase-producing Enterobacterales (CPE) are rapidly increasing worldwide, also in Europe. Although prevalence of CPE in Germany is comparatively low, the National Reference Centre for Multidrug-resistant Gram-negative Bacteria noted annually increasing numbers of NDM-5-producing Escherichia coli isolates.AimAs part of our ongoing surveillance programme, we characterised NDM-5-producing E. coli isolates received between 2013 and 2019 using whole genome sequencing (WGS).MethodsFrom 329 identified NDM-5-producing E. coli, 224 isolates from known geographical locations were subjected to Illumina WGS. Analyses of 222 sequenced isolates included multilocus sequence typing (MLST), core genome (cg)MLST and single-nucleotide polymorphism (SNP)-based analyses.ResultsResults of cgMLST revealed genetically distinct clusters for many of the 43 detected sequence types (ST), of which ST167, ST410, ST405 and ST361 predominated. The SNP-based phylogenetic analyses combined with geographical information identified sporadic cases of nosocomial transmission on a small spatial scale. However, we identified large clusters corresponding to clonal dissemination of ST167, ST410, ST405 and ST361 strains in consecutive years in different regions in Germany.ConclusionOccurrence of NDM-5-producing E. coli rose in Germany, which was to a large extent due to the increased prevalence of isolates belonging to the international high-risk clones ST167, ST410, ST405 and ST361. Of particular concern is the supra-regional dissemination of these epidemic clones. Available information suggest community spread of NDM-5-producing E. coli in Germany, highlighting the importance of epidemiological investigation and an integrated surveillance system in the One Health framework.

NDM-5-Producing Escherichia coli Co-Harboring mcr-1 Gene in Companion Animals in China

Carbapenem and colistin are important antibiotics for the treatment of infections caused by multidrug-resistant Gram-negative pathogens. Here, we isolated the blaNDM-5-harboring Escherichia coli in companion animals in healthy or diseased companion animals from veterinary clinics in six cities in China from July to November 2016. A total of 129 rectal swabs of healthy or diseased dogs and cats were collected from veterinary clinics in six different cities in China, and the isolates were subjected to carbapenem and colistin susceptibility testing. Resistance genes were confirmed using PCR. Conjugation experiments were conducted to determine the transferability of antibiotic resistance genes (ARGs) in the strains. The isolated rate of blaNDM-5-harboring E. coli strains was 3.88% (five strains). These five strains were multidrug resistant to at least three antibiotics and corresponded to four sequence types including ST101. The blaNDM-5 gene was located on 46 kb IncX3 plasmids in these five strains, and the genetic contexts were shared and were nearly identical to the K. pneumoniae plasmid pNDM5-IncX3 from China. In addition, one strain (CQ6-1) co-harbored blaNDM-5-encoding-IncX3 plasmid along with a mcr-1-encoding-IncX4 plasmid, and their corresponding genetic environments were identical to the blaNDM-5-IncX3 and mcr-1-IncX4 hybrid plasmid reported previously from the same area and from the same clinic. The results indicated that the similar genetic contexts were shared between these isolates from companion animals, and the IncX3-type plasmids played a key role in the spread of blaNDM-5 among these bacteria.

Genetic Characterization of Carbapenem-Resistant Klebsiella spp. from Municipal and Slaughterhouse Wastewater

Currently, human and veterinary medicine are threatened worldwide by an increasing resistance to carbapenems, particularly present in opportunistic Enterobacterales pathogens (e.g., Klebsiella spp.). However, there is a lack of comprehensive and comparable data on their occurrence in wastewater, as well as on the phenotypic and genotypic characteristics for various countries including Germany. Thus, this study aims to characterize carbapenem-resistant Klebsiella spp. isolated from municipal wastewater treatment plants (mWWTPs) and their receiving water bodies, as well as from wastewater and process waters from poultry and pig slaughterhouses. After isolation using selective media and determination of carbapenem (i.e., ertapenem) resistance using broth microdilution to apply epidemiological breakpoints, the selected isolates (n = 30) were subjected to WGS. The vast majority of the isolates (80.0%) originated from the mWWTPs and their receiving water bodies. In addition to ertapenem, Klebsiella spp. isolates exhibited resistance to meropenem (40.0%) and imipenem (16.7%), as well as to piperacillin-tazobactam (50.0%) and ceftolozan-tazobactam (50.0%). A high diversity of antibiotic-resistance genes (n = 68), in particular those encoding β-lactamases, was revealed. However, with the exception of bla_GES-5-like, no acquired carbapenemase-resistance genes were detected. Virulence factors such as siderophores (e.g., enterobactin) and fimbriae type 1 were present in almost all isolates. A wide genetic diversity was indicated by assigning 66.7% of the isolates to 12 different sequence types (STs), including clinically relevant ones (e.g., ST16, ST252, ST219, ST268, ST307, ST789, ST873, and ST2459). Our study provides information on the occurrence of carbapenem-resistant, ESBL-producing Klebsiella spp., which is of clinical importance in wastewater and surface water in Germany. These findings indicate their possible dissemination in the environment and the potential risk of colonization and/or infection of humans, livestock and wildlife associated with exposure to contaminated water sources.

Comparative genomic analysis of plasmids encoding metallo-β-lactamase NDM-5 in Enterobacterales Korean isolates from companion dogs

Carbapenems are broad-spectrum antibiotics widely used for the treatment of human infections caused by multidrug-resistant (MDR) Gram-negative bacteria. However, emerging carbapenemase-producing Enterobacterales (CPE) are rising as a public threat to human and animal health. We screened clinical bacterial isolates from 241 dogs and 18 cats hospitalized at Veterinary Medical Teaching Hospital, Seoul National University, from 2018 to 2020 for carbapenemase production. In our study, 5 strains of metallo-β-lactamase NDM-5-producing Escherichia coli and Klebsiella pneumoniae were isolated from 4 different dogs. Multilocus sequence typing (MLST) results showed that all E. coli strains were ST410 and all K. pneumoniae strains were ST378. Whole genome analysis of the plasmid showed that blaNDM-5 is carried on a IncX3 plasmid, showing a high concordance rate with plasmids detected worldwide in human and animal isolates. The blaNDM gene was associated with the bleMBL gene and the ISAba125 element, truncated with the IS5 element. The results of this study show that CPE has already become as a threat to both animals and humans in our society, posing the necessity to solve it in terms of "One Health". Therefore, preventive strategies should be developed to prevent the spread of CPE in animal and human societies.

An Emerging Clone, Klebsiellapneumoniae Carbapenemase 2-Producing K. pneumoniae Sequence Type 16, Associated With High Mortality Rates in a CC258-Endemic Setting

Background

Carbapenemase-producing Klebsiella pneumoniae has become a global priority, not least in low- and middle-income countries. Here, we report the emergence and clinical impact of a novel Klebsiella pneumoniae carbapenemase–producing K. pneumoniae (KPC-KP) sequence type (ST) 16 clone in a clonal complex (CC) 258–endemic setting.

Methods

In a teaching Brazilian hospital, a retrospective cohort of adult KPC-KP bloodstream infection (BSI) cases (January 2014 to December 2016) was established to study the molecular epidemiology and its impact on outcome (30-day all-cause mortality). KPC-KP isolates underwent multilocus sequence typing. Survival analysis between ST/CC groups and risk factors for fatal outcome (logistic regression) were evaluated. Representative isolates underwent whole-genome sequencing and had their virulence tested in a Galleria larvae model.

Results

One hundred sixty-five unique KPC-KP BSI cases were identified. CC258 was predominant (66%), followed by ST16 (12%). The overall 30-day mortality rate was 60%; in contrast, 95% of ST16 cases were fatal. Patients’ severity scores were high and baseline clinical variables were not statistically different across STs. In multivariate analysis, ST16 (odds ratio [OR], 21.4; 95% confidence interval [CI], 2.3–202.8; P = .008) and septic shock (OR, 11.9; 95% CI, 4.2–34.1; P < .001) were independent risk factors for fatal outcome. The ST16 clone carried up to 14 resistance genes, including bla_KPC-2 in an IncFIBpQIL plasmid, KL51 capsule, and yersiniabactin virulence determinants. The ST16 clone was highly pathogenic in the larvae model.

Conclusions

Mortality rates were high in this KPC-KP BSI cohort, where CC258 is endemic. An emerging ST16 clone was associated with high mortality. Our results suggest that even in endemic settings, highly virulent clones can rapidly emerge demanding constant monitoring.

Investigation of possible clonal transmission of carbapenemase-producing Klebsiella pneumoniae complex member isolates in Denmark using core genome MLST and National Patient Registry Data

OBJECTIVES

The aim of this study was to identify clonally-related carbapenemase-producing Klebsiella pneumoniae complex members that could be involved in outbreaks among hospitalized patients in Denmark, and to identify possible epidemiological links.

METHODS

From January 2014 to June 2018, 103 isolates belonging to the K. pneumoniae complex were collected from 102 patients. From the whole-genome sequencing (WGS) data, presence of genes encoding carbapenemase and multilocal sequence typing (MLST) data were extracted. Core genome MLST (cgMLST) cluster analysis was performed. Using data from the Danish National Patient Registry (DNPR) and reported travel history, presumptive outbreaks were investigated for possible epidemiological links.

RESULTS

The most common detected carbapenemase gene was bla_OXA-48, followed by bla_NDM-1. The 103 K. pneumoniae complex isolates belonged to 47 sequence types (STs) and cgMLST subdivided the isolates into 80 different complex types. cgMLST identified 13 clusters with 2-4 isolates per cluster. For five of the 13 clusters, a direct link (the patients stayed at the same ward on the same day) could be detected between at least some of the patients. In two clusters, the patients resided simultaneously at the same hospital, but not the same ward. A possible link (same ward within 1-13 days) was detected for the patients in one cluster. For five clusters detected by cgMLST, no epidemiological link could be detected using data from DNPR.

CONCLUSION

In this study, cgMLST combined with patient hospital admission data and travel information was found to be a reliable and detailed approach to detect possible clonal transmission of carbapenemase-producing K. pneumoniae complex members.

First Reported Nosocomial Outbreak Of NDM-5-Producing Klebsiella pneumoniae In A Neonatal Unit In China

Purpose

Carbapenem-resistant Klebsiella pneumoniae (CRKP) have emerged worldwide and also being a major threat to children and neonate. In this study, we describe a nosocomial outbreak of NDM-5-producing Klebsiella pneumoniae in neonatal unit of a teaching hospital in China from September 2015 to September 2016.

Patients and methods

We collected 12 carbapenem-resistant K. pneumoniae outbreak strains from 12 newborns and characterized these isolates for their antimicrobial susceptibility, clone relationships, and multi-locus sequence types using vitek-2 compact system, pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST). Resistant genes were detected by using PCR and sequencing. Plasmid conjugation experiment was carried out to determine the transferability of carbapenem resistance. PCR-based replicon typing (PBRT), S1 nuclease-PFGE, and southern blotting were conducted for plasmid profiling.

Results

All 12 K. pneumoniae isolates were resistant to carbapenems and carried bla_NDM-5, bla_TEM-1 and bla_SHV-11. Furthermore, PFGE analysis showed that NDM-5-producing K. pneumoniae were clonally related and MLST assigned them to sequence type 337. Conjugative assays showed that plasmids harboring bla_NDM-5 gene were self-transmissible. Plasmid analysis suggested that all bla_NDM-5 gene located on a ~45 kb IncX3 type plasmid.

Conclusion

To the best of our knowledge, this is the first report of a clone outbreak of bla_NDM-5-carrying K. pneumoniae isolates from neonates. There is an urgent need for effective infection control measures to prevent bla_NDM-5 variants from becoming epidemic in the neonates in the future.

Outbreak of blaNDM-5-Harboring Klebsiella pneumoniae ST290 in a Tertiary Hospital in China

The emergence of carbapenem-resistant Klebsiella pneumoniae (CRKP) has posed a great threat to public health. Among 133 nonduplicated CRKP isolates collected between September 2016 and November 2017 in a tertiary hospital in China, 89 (89/133, 66.9%) and 31 (31/133, 23.3%) were positive for bla_NDM-5 and bla_KPC-2. Multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) revealed that ST290 represented the majority of NDM-5 producers (67/89, 75.3%) and PFGE cluster E accounted for 50 (50/67, 74.6%) ST290 isolates from the burn ward, suggesting that K. pneumoniae ST290 clone carrying bla_NDM-5 resulted in an outbreak in this hospital. Whole genome sequencing of the plasmid carrying bla_NDM-5 showed that the resistance gene bla_NDM-5 was located in a ∼49 kb multireplicon plasmid with a peculiar insertion of ISKpn19 of the IncX3-type plasmid. To the best of our knowledge, this is the first report of outbreak of K. pneumoniae ST290 clone carrying bla_NDM-5.

Carbapenemase-producing bacteria in food-producing animals, wildlife and environment: A challenge for human health

Antimicrobial resistance is an increasing global health problem and one of the major concerns for economic impacts worldwide. Recently, resistance against carbapenems (doripenem, ertapenem, imipenem, meropenem), which are critically important antimicrobials for human cares, poses a great risk all over the world. Carbapenemases are β-lactamases belonging to different Ambler classes (A, B, D) and encoded by both chromosomal and plasmidic genes. They hydrolyze a broad variety of β-lactams, including carbapenems, cephalosporins, penicillins and aztreonam. Despite several studies in human patients and hospital settings have been performed in European countries, the role of livestock animals, wild animals and the terrestrial and aquatic environment in the maintenance and transmission of carbapenemase- producing bacteria has been poorly investigated. The present review focuses on the carbapenemase-producing bacteria detected in pigs, cattle, poultry, fish, mollusks, wild birds and wild mammals in Europe as well as in non-European countries, investigating the genetic mechanisms for their transmission among food-producing animals and wildlife. To shed light on the important role of the environment in the maintenance and genetic exchange of resistance determinants between environmental and pathogenic bacteria, studies on aquatic sources (rivers, lakes, as well as wastewater treatment plants) are described.

Characterization of an NDM-5 carbapenemase-producing Escherichia coli ST156 isolate from a poultry farm in Zhejiang, China

BACKGROUND

The emergence of carbapenem-resistant Enterobacteriaceae strains has posed a severe threat to public health in recent years. The mobile elements carrying the New Delhi metallo-β-lactqtamase (NDM) gene have been regarded as the major mechanism leading to the rapid increase of carbapenem-resistant Enterobacteriaceae strains isolated from clinics and animals.

RESULTS

We describe an NDM-5-producing Escherichia coli strain, ECCRA-119 (sequence type 156 [ST156]), isolated from a poultry farm in Zhejiang, China. ECCRA-119 is a multidrug-resistant (MDR) isolate that exhibited resistance to 27 antimicrobial compounds, including imipenem and meropenem, as detected by antimicrobial susceptibility testing (AST). The complete genome sequence of the ECCRA-119 isolate was also obtained using the PacBio RS II platform. Eleven acquired resistance genes were identified in the chromosome; four were detected in plasmid pTB201, while six were detected in plasmid pTB202. Importantly, the carbapenem-resistant gene blaNDM-5 was detected in the IncX3 plasmid pTB203. In addition, seven virulence genes and one metal-resistance gene were also detected. The results of conjugation experiments and the transfer regions identification indicated that the blaNDM-5-harboring plasmid pTB203 could be transferred between E. coli strains.

CONCLUSIONS

The results reflected the severe bacterial resistance in a poultry farm in Zhejiang province and increased our understanding of the presence and transmission of the blaNDM-5 gene.

Emergence of New Delhi Metallo-β-Lactamase (NDM-5) in Klebsiella quasipneumoniae from Neonates in a Nigerian Hospital

Outbreaks of infection occur more often than they are reported in most developing countries, largely due to poor diagnostic services. A Klebsiella species bacteremia outbreak in a newborn unit with high mortality was recently encountered at a location being surveilled for childhood bacteremia. These surveillance efforts offered the opportunity to determine the cause of this neonatal outbreak. In this report, we present the whole-genome sequences of New Delhi metallo-β-lactamase (NDM-5)-containing Klebsiella quasipneumoniae subsp. similipneumoniae bloodstream isolates from a neonatal bacteremia outbreak at a tertiary hospital in Nigeria and as part of the largest collection of K. pneumoniae bloodstream isolates from children in Africa. Comparative analysis of the genetic environment surrounding the NDM-5 genes revealed nearly perfect sequence identity to blaNDM-5-bearing IncX3-type plasmids from other members of the EnterobacteriaceaeIMPORTANCE Carbapenem-resistant Klebsiella pneumoniae is of global health importance, yet there is a paucity of genome-based studies in Africa. Here we report fatal blood-borne NDM-5-producing K. quasipneumoniae subsp. similipneumoniae infections from Nigeria, Africa. New Delhi metallo-β-lactamase (NDM)-producing Klebsiella spp. are responsible for high mortality and morbidity, with the NDM-5 variant showing elevated carbapenem resistance. The prevalence of NDM-5 in Klebsiella has been limited primarily to K. pneumoniae, with only one isolate being collected from Africa. During an outbreak of sepsis in a teaching hospital in Nigeria, five NDM-5-producing K. quasipneumoniae subsp. similipneumoniae sequence type 476 isolates were identified. Given the increased resistance profile of these strains, this study highlights the emerging threat of blaNDM-5 dissemination in hospital environments. The observation of these NDM-5-producing isolates in Africa stresses the urgency to improve monitoring and clinical practices to reduce or prevent the further spread of resistance.

The proper structure of a biosafety system as a way of reducing the vulnerability of a society, economy or state in the face of a biogenic threat

To understand how vulnerable are a society, an economy and a state in the face of a biohazard, one should attempt to identify any potential holes in the national biosafety system, such as the lack of important components or technologies for biological monitoring and the inadequacy of existing analytical methods used to prevent or counteract biogenic threats. In Russia, biological monitoring is quite advanced. However, the agencies that ensure proper functioning of its components lack collaboration and do not form a well-coordinated network. Each of such agencies alone cannot provide comprehensive information on the subject. In the Russian Federation, there are at least 4 state-funded programs that collect epidemiological data and are quite efficient in performing the narrow task of monitoring infections. But because there is no central database where epidemiological data can be channeled and subsequently shared, these agencies do not complete each other. This leaves the Russian society, economy and state vulnerable to biogenic threats. We need an adequately organized, modern, fully functional and effective system for monitoring biohazards that will serve as a basis for the national biosafety system and also a tool for the identification and elimination of its weaknesses.

Extended-spectrum β-lactamase-producing and carbapenemase-producing Enterobacteriaceae

Antimicrobial resistance (AMR) is a global public-health emergency, which threatens the advances made by modern medical care over the past century. The World Health Organization has recently published a global priority list of antibiotic-resistant bacteria, which includes extended-spectrum β-lactamase-producing Enterobacteriaceae and carbapenemase-producing Enterobacteriaceae. In this review, we highlight the mechanisms of resistance and the genomic epidemiology of these organisms, and the impact of AMR.

Dissemination of blaNDM-5 gene via an IncX3-type plasmid among non-clonal Escherichia coli in China

Background

The emergence and spread of New Delhi metallo-β-lactamase-producing Enterobacteriaceae has been a serious challenge to manage in the clinic due to its rapid dissemination of multi-drug resistance worldwide. As one main type of carbapenemases, New Delhi metallo-β-lactamase (NDM)is able to confer resistance to almost all β-lactams, including carbapenems, in Enterobacteriaceae. Recently, New Delhi metallo-β-lactamase-5 attracted extensive attention because of increased resistance to carbapenems and widespread dissemination. However, the dissemination mechanism of blaNDM-5 gene remains unclear.

Methods

A total of 224 carbapenem-resistant Enterobacteriaceae isolates (CRE) were collected from different hospitals in Zhejiang province. NDM-5-positive isolates were identified and subjected to genotyping, susceptibility testing, and clinical data analysis. We established the genetic location of blaNDM-5 with southern blot hybridisation, and analysed plasmids containing blaNDM-5 with filter mating and DNA sequencing.

Results

Eleven New Delhi metallo-β-lactamase-5 (NDM-5)-producing strains were identified, including 9 Escherichia coli strains, 1 Klebsiella pneumoniae strain, and 1 Citrobacter freundii strain. No epidemiological links for E. coli isolates were identified by multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). S1-PFGE and southern blot suggested that the blaNDM-5 gene was located on a 46-kb IncX3-type plasmid in all isolates. Nine of the 11 isolates (81.8%) tested could successfully transfer their carbapenem-resistant phenotype to E. coli strain C600. Moreover, sequence analysis further showed that this plasmid possessed high sequence similarity to most of previously reported blaNDM-5-habouring plasmids in China.

Conclusion

The present data in this study showed the IncX3 type plasmid played an important role in the dissemination of blaNDM-5 in Enterobacteriaceae. In addition, to the best of our knowledge, this report is the first to isolate both E. coli and C. freundii strains carrying blaNDM-5 from one single patient, which further indicated the possibility of blaNDM-5 transmission among diverse species. Close surveillance is urgently needed to monitor the further dissemination of NDM-5-producing isolates.

Transformation of animal genomics by next-generation sequencing technologies: a decade of challenges and their impact on genetic architecture

For more than a quarter of a century, sequencing technologies from Sanger's method to next-generation high-throughput techniques have provided fascinating opportunities in the life sciences. The continuing upward trajectory of sequencing technologies will improve livestock research and expedite the development of various new genomic and technological studies with farm animals. The use of high-throughput technologies in livestock research has increased interest in metagenomics, epigenetics, genome-wide association studies, and identification of single nucleotide polymorphisms and copy number variations. Such studies are beginning to provide revolutionary insights into biological and evolutionary processes. Farm animals, such as cattle, swine, and horses, have played a dual role as economically and agriculturally important animals as well as biomedical research models. The first part of this study explores the current state of sequencing methods, many of which are already used in animal genomic studies, and the second part summarizes the state of cattle, swine, horse, and chicken genome sequencing and illustrates its achievements during the last few years. Finally, we describe several high-throughput sequencing approaches for the improved detection of known, unknown, and emerging infectious agents, leading to better diagnosis of infectious diseases. The insights from viral metagenomics and the advancement of next-generation sequencing will strongly support specific and efficient vaccine development and provide strategies for controlling infectious disease transmission among animal populations and/or between animals and humans. However, prospective sequencing technologies will require further research and in-field testing before reaching the marketplace.

Characterization of NDM-5-positive extensively resistant Escherichia coli isolates from dairy cows

The aim of this study was to investigate the prevalence of bla_NDM-5 gene in Escherichia coli isolates from dairy cows and to characterize the molecular traits of the bla_NDM-5-positive isolates. A total of 169 cows were sampled (169 feces and 169 raw milk samples) in three dairy farms in Jiangsu Province and 203 E. coli isolates were recovered. Among these strains, three isolates carried bla_NDM-5 gene, including one co-harboring mcr-1, which belonged to sequence type 446 and the other two belonged to ST2. Susceptibility testing revealed that the three bla_NDM-5-positive isolates showed extensive resistance to antimicrobials. The bla_NDM-5 gene was located on a ∼46-kb IncX3 transferrable pNDM-MGR194-like plasmid in all three isolates, while mcr-1 was located on a ∼260-kb IncHI2 plasmid pXGE1mcr. Competition experiments revealed that acquisition of bla_NDM-5 or mcr-1-bearing plasmid can incur fitness cost of bacterial host, however, plasmid stability testing showed that both bla_NDM-5 and mcr-1-carrying plasmid maintained stable in the hosts after ten passages without antimicrobial selection. Whole genome sequencing revealed that the mcr-1 gene coexisted with multiple resistance genes in pXGE1mcr and the backbone of this plasmid was similar to that of previously reported mcr-1-positive plasmid pHNSHP45-2. Moreover, pXGE1mcr could be conjugated into clinical NDM-5-positive E. coli isolates in vitro, thereby generating strains that approached pan-resistance. Active surveillance efforts are imperative to monitor the prevalence of bla_NDM-5 and mcr-1 in carbapenem-resistant Enterobacteriaceae from dairy farms throughout China.

Outbreak of NDM-1-Producing Klebsiella pneumoniae in a Dutch Hospital, with Interspecies Transfer of the Resistance Plasmid and Unexpected Occurrence in Unrelated Health Care Centers

In the Netherlands, the number of cases of infection with New Delhi metallo-beta-lactamase (NDM)-positive Enterobacteriaceae is low. Here, we report an outbreak of NDM-1-producing Klebsiella pneumoniae infection in a Dutch hospital with interspecies transfer of the resistance plasmid and unexpected occurrence in other unrelated health care centers (HCCs). Next-generation sequencing was performed on 250 carbapenemase-producing Enterobacteriaceae isolates, including 42 NDM-positive isolates obtained from 29 persons at the outbreak site. Most outbreak isolates were K. pneumoniae (n = 26) and Escherichia coli (n = 11), but 5 isolates comprising three other Enterobacteriaceae species were also cultured. The 26 K. pneumoniae isolates had sequence type 873 (ST873), as did 7 unrelated K. pneumoniae isolates originating from five geographically dispersed HCCs. The 33 ST873 isolates that clustered closely together using whole-genome multilocus sequence typing (wgMLST) carried the same plasmids and had limited differences in the resistome. The 11 E. coli outbreak isolates showed great variety in STs, did not cluster using wgMLST, and showed considerable diversity in resistome and plasmid profiles. The bla_NDM-1 gene-carrying plasmid present in the ST873 K. pneumoniae isolates was found in all the other Enterobacteriaceae species cultured at the outbreak location and in a single E. coli isolate from another HCC. We describe a hospital outbreak with an NDM-1-producing K. pneumoniae strain from an unknown source that was also found in patients from five other Dutch HCCs in the same time frame without an epidemiological link. Interspecies transfer of the resistance plasmid was observed in other Enterobacteriaceae species isolated at the outbreak location and in another HCC.

Reprint of "Application of next generation sequencing in clinical microbiology and infection prevention"

Current molecular diagnostics of human pathogens provide limited information that is often not sufficient for outbreak and transmission investigation. Next generation sequencing (NGS) determines the DNA sequence of a complete bacterial genome in a single sequence run, and from these data, information on resistance and virulence, as well as information for typing is obtained, useful for outbreak investigation. The obtained genome data can be further used for the development of an outbreak-specific screening test. In this review, a general introduction to NGS is presented, including the library preparation and the major characteristics of the most common NGS platforms, such as the MiSeq (Illumina) and the Ion PGM™ (ThermoFisher). An overview of the software used for NGS data analyses used at the medical microbiology diagnostic laboratory in the University Medical Center Groningen in The Netherlands is given. Furthermore, applications of NGS in the clinical setting are described, such as outbreak management, molecular case finding, characterization and surveillance of pathogens, rapid identification of bacteria using the 16S-23S rRNA region, taxonomy, metagenomics approaches on clinical samples, and the determination of the transmission of zoonotic micro-organisms from animals to humans. Finally, we share our vision on the use of NGS in personalised microbiology in the near future, pointing out specific requirements.

Whole genome sequencing reveals high-resolution epidemiological links between clinical and environmental Klebsiella pneumoniae

Background

Klebsiella pneumoniae is a gram-negative bacterial species capable of occupying a broad range of environmental and clinical habitats. Known as an opportunistic pathogen, it has recently become a major causative agent of clinical infections worldwide. Despite growing knowledge about the highly diverse population of K. pneumoniae, the evolution and clinical significance of environmental K. pneumoniae, as well as the relationship between clinical and environmental K. pneumoniae, are poorly defined.

Methods

We isolated and sequenced K. pneumoniae from in-patients in a single hospital in Thailand, as well as hospital sewage, and surrounding canals and farms within a 20-km radius.

Results

Phylogenetic analysis of 77 K. pneumoniae (48 clinical and 29 non-clinical isolates) demonstrated that the two groups were intermixed throughout the tree and in some cases resided in the same clade, suggesting recent divergence from a common ancestor. Phylogenetic comparison of the 77 Thai genomes with 286 K. pneumoniae from a global collection showed that Thai isolates were closely related to the clinical sub-population of the global collection, indicating that Thai clinical isolates belonged to globally circulating lineages. Dating of four Thai K. pneumoniae clades indicated that they emerged between 50 and 150 years ago. Despite their phylogenetic relatedness, virulence factors and β-lactamase resistance genes were more numerous in clinical than in environmental isolates. Our results indicate that clinical and environmental K. pneumoniae are closely related, but that hospitals may select for isolates with a more resistant and virulent genotype.

Conclusions

These findings highlight the clinical relevance of environmental K. pneumoniae isolates.

Electronic supplementary material

The online version of this article (doi:10.1186/s13073-017-0397-1) contains supplementary material, which is available to authorized users.

Application of next generation sequencing in clinical microbiology and infection prevention

Current molecular diagnostics of human pathogens provide limited information that is often not sufficient for outbreak and transmission investigation. Next generation sequencing (NGS) determines the DNA sequence of a complete bacterial genome in a single sequence run, and from these data, information on resistance and virulence, as well as information for typing is obtained, useful for outbreak investigation. The obtained genome data can be further used for the development of an outbreak-specific screening test. In this review, a general introduction to NGS is presented, including the library preparation and the major characteristics of the most common NGS platforms, such as the MiSeq (Illumina) and the Ion PGM™ (ThermoFisher). An overview of the software used for NGS data analyses used at the medical microbiology diagnostic laboratory in the University Medical Center Groningen in The Netherlands is given. Furthermore, applications of NGS in the clinical setting are described, such as outbreak management, molecular case finding, characterization and surveillance of pathogens, rapid identification of bacteria using the 16S-23S rRNA region, taxonomy, metagenomics approaches on clinical samples, and the determination of the transmission of zoonotic micro-organisms from animals to humans. Finally, we share our vision on the use of NGS in personalised microbiology in the near future, pointing out specific requirements.

Acquisition of a High Diversity of Bacteria during the Hajj Pilgrimage, Including Acinetobacter baumannii with blaOXA-72 and Escherichia coli with blaNDM-5 Carbapenemase Genes

Pilgrims returning from the Hajj (pilgrimage to Mecca) can be carriers of multidrug-resistant bacteria (MDR). Pharyngeal and rectal swab samples were collected from 98 pilgrims before and after they traveled to the Hajj in 2014 to investigate the acquisition of MDR bacteria. The bacterial diversity in pharyngeal swab samples was assessed by culture with selective media. There was a significantly higher diversity of bacteria in samples collected after the return from the Hajj than in those collected before (P = 0.0008). Surprisingly, Acinetobacter baumannii strains were isolated from 16 pharyngeal swab samples (1 sample taken during the Hajj and 15 samples taken upon return) and 26 post-Hajj rectal swab samples, while none were isolated from samples taken before the Hajj. Testing of all samples by real-time PCR targeting blaOXA-51 gave positive results for only 1% of samples taken during the Hajj, 21/90 (23.3%) pharyngeal swab samples taken post-Hajj, and 35/90 (38.9%) rectal swab samples taken post-Hajj. One strain of A. baumannii isolated from the pharynx was resistant to imipenem and harbored a blaOXA-72 carbapenemase gene. Multilocus sequence typing analysis of 43 A. baumannii isolates revealed a huge diversity of 35 sequence types (STs), among which 18 were novel STs reported for the first time in this study. Moreover, we also found one Escherichia coli isolate, collected from a rectal swab sample from a pilgrim taken after the Hajj, which harbored blaNDM-5, blaCTX-M-15, blaTEM-1, and aadA2 (ST2659 and ST181). In conclusion, pilgrims are at a potential risk of acquiring and transmitting MDR Acinetobacter spp. and carbapenemase-producing Gram-negative bacteria during the Hajj season.

Occurrence and characterization of blaNDM-5-positive Klebsiella pneumoniae isolates from dairy cows in Jiangsu, China

OBJECTIVES

To investigate the epidemiological characteristics and the surrounding genetic structure of the bla_NDM-5 gene in Klebsiella pneumoniae derived from dairy cows in Jiangsu Province, China.

METHODS

Ten carbapenem-resistant K. pneumoniae were collected from three dairy farms and were screened for the presence of carbapenemase genes using PCR and sequencing. PFGE and MLST were conducted to analyse the genetic relatedness of the bla_NDM-5-harbouring K. pneumoniae isolates. The location of bla_NDM-5 was identified by S1 nuclease-PFGE and Southern blotting. The transferability and profiles of bla_NDM-5-carrying plasmids were analysed by conjugation experiments, and PCR-based replicon typing and RFLP, respectively. The surrounding genetic structure of the bla_NDM-5 gene was obtained using WGS and PCR mapping.

RESULTS

All 10 K. pneumoniae from dairy cows harboured the bla_NDM-5 gene, exhibited resistance to multiple antimicrobials and belonged to five STs, of which ST1661 and ST2108 were the most prevalent. The bla_NDM-5 gene was located on the ∼46 kb IncX3 plasmid in all isolates and these plasmids could be conjugated to an Escherichia coli recipient with no additional resistance profiles transferred. All bla_NDM-5-carrying plasmids shared similar genetic contexts and were nearly identical to that of the human K. pneumoniae plasmid (pNDM-MGR194) previously reported in India.

CONCLUSIONS

This was the first case of bla_NDM-5-positive K. pneumoniae identified from dairy cows in China. The IncX3 pNDM-MGR194-like plasmid disseminated among cow farms should be highlighted and its potential role in mediating transmission of the bla_NDM gene between bacteria from humans and animals requires further monitoring.

Identification of an NDM-5-producing Escherichia coli Sequence Type 167 in a Neonatal Patient in China

Emergence of New Delhi metallo-β-lactamase-producing Enterobacteriaceae has become a challenging threat to public health. Two carbapenem-resistant Escherichia coli, strain QD28 and QD29, were recovered from the aspirating sputum of a neonate and the urine of an adult in a Chinese hospital in 2013. Molecular typing revealed that both isolates belonged to the sequence type 167, but they were clonally diverse. Both isolates exhibited resistance to carbapenems, cephalosporins, ciprofloxacin, gentamicin, piperacillin-tazobactam and trimethoprim-sulfamethoxazole. In addition, strain QD28 was also resistant to aztreonam, and strain QD29 was resistant to amikacin, fosfomycin and minocycline. Antimicrobial resistance gene screening revealed that strain QD28 harbored aac(6′)-Ib, bla_CTX-M-14, bla_NDM-5, bla_TEM-1 and sul1 genes, and strain QD29 harbored aac(6′)-Ib, bla_CTX-M-3, bla_NDM-5, bla_TEM-1, rmtB, sul1 and sul2 genes. The bla_NDM-5 gene was found to be located on a 46-kb plasmid in two isolates, and further sequence analysis showed that this plasmid was highly similar to the previously reported IncX3 plasmid pNDM-MGR194 in India. This is the first identification of bla_NDM-5-carrying E. coli in the neonatal infection.

Global Dissemination of Carbapenemase-Producing Klebsiella pneumoniae: Epidemiology, Genetic Context, Treatment Options, and Detection Methods

The emergence of carbapenem-resistant Gram-negative pathogens poses a serious threat to public health worldwide. In particular, the increasing prevalence of carbapenem-resistant Klebsiella pneumoniae is a major source of concern. K. pneumoniae carbapenemases (KPCs) and carbapenemases of the oxacillinase-48 (OXA-48) type have been reported worldwide. New Delhi metallo-β-lactamase (NDM) carbapenemases were originally identified in Sweden in 2008 and have spread worldwide rapidly. In this review, we summarize the epidemiology of K. pneumoniae producing three carbapenemases (KPCs, NDMs, and OXA-48-like). Although the prevalence of each resistant strain varies geographically, K. pneumoniae producing KPCs, NDMs, and OXA-48-like carbapenemases have become rapidly disseminated. In addition, we used recently published molecular and genetic studies to analyze the mechanisms by which these three carbapenemases, and major K. pneumoniae clones, such as ST258 and ST11, have become globally prevalent. Because carbapenemase-producing K. pneumoniae are often resistant to most β-lactam antibiotics and many other non-β-lactam molecules, the therapeutic options available to treat infection with these strains are limited to colistin, polymyxin B, fosfomycin, tigecycline, and selected aminoglycosides. Although, combination therapy has been recommended for the treatment of severe carbapenemase-producing K. pneumoniae infections, the clinical evidence for this strategy is currently limited, and more accurate randomized controlled trials will be required to establish the most effective treatment regimen. Moreover, because rapid and accurate identification of the carbapenemase type found in K. pneumoniae may be difficult to achieve through phenotypic antibiotic susceptibility tests, novel molecular detection techniques are currently being developed.

Further Spread of bla NDM-5 in Enterobacteriaceae via IncX3 Plasmids in Shanghai, China

One hundred and two carbapenem-resistant Enterobacteriaceae (CRE) strains were isolated in a teaching hospital in Shanghai, China from 2012 to 2015. In a follow-up study, four New Delhi metallo-β-lactamase-5 (NDM-5)-producing strains were identified after screening these CRE strains, including 1 Klebsiella pneumoniae strain (RJ01), 1 Proteus mirabilis strain (RJ02), and 2 Escherichia coli strains (RJ03 and RJ04). All K. pneumoniae and E. coli isolates were resistant to carbapenems, third-generation cephalosporins, and piperacillin-tazobactam, but were susceptible to amikacin. No epidemiological links for either E. coli isolate were found by multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). However, MLST revealed a novel sequence type, ST2250, of the K. pneumoniae RJ01 strain. Inc types and sizes of bla_NDM-5-carrying plasmids differed among the four isolates, although in P. mirabilis RJ02 and E. coli RJ03, bla_NDM-5 was carried by conjugative IncX3 plasmids of nearly the same size (∼40 kb). Investigation of the genetic background of sequences flanking the bla_NDM-5 gene showed that all four isolates shared the same genetic content (IS3000-ΔISAba125-IS5-bla_NDM-5-ble-trpF-dsbC-IS26-ΔumuD), which was identical to that of the pNDM_MGR194 plasmid circulating in India. This is the first identification of bla_NDM-5 in P. mirabilis, which suggests its further spread to Enterobacteriaceae, and indicates that IncX3 plasmids may play an important role in potentiating the spread of bla_NDM.