Whole Genome Sequencing detects Inter-Facility Transmission of Carbapenem-resistant Klebsiella pneumoniae

Interhospital Spread of blaVIM-1- and blaCTX-M-15-Producing K. pneumoniae ST15 on an IncR Plasmid in Southern Spain

In 2014-2015, the main CTX-M-15- and OXA-48-producing clone in our region was ST15. Recently, K. pneumoniae ST15 isolates co-producing VIM-1 and CTX-M-15 were detected in several hospitals. The aim was to study the emergence and acquisition of this carbapenemase. Between 2017 and 2019, four hospitals submitted twenty-nine VIM-1- and CTX-M-15-producing K. pneumoniae ST15 isolates to our laboratory. Seven representatives of each XbaI PFGE pulsotype were sequenced using short- and long-read technologies. RAST, CGE databases, and Pathogenwatch were used for resistance determinants and capsule-type analysis. Plasmid comparison was performed with Easyfig2.1. Phylogenetic analysis included other contemporary ST15 isolates from Spain. The 29 isolates were clustered into seven different pulsotypes. The selected genomes, from three hospitals in two different provinces, were clustered together (fewer than 35 alleles) and differed by more than 100 alleles from other ST15 isolates obtained in the region. These seven isolates harbored one IncR plasmid (200-220 kb) with a common backbone and four regions flanked by IS26: one contained blaVIM-1, another contained blaCTX-M-15, the third contained blaOXA-1, and the fourth harbored heavy-metal-tolerance genes. The two initial plasmids, from two different centers, were identical, and rearrangement of four regions was observed in the five subsequent plasmids. Our findings showed the first intercenter dissemination of IncR plasmids carrying blaVIM-1, blaCTX-M-15, and metal-tolerance genes mediated by a new lineage of K. pneumoniae ST15. Two different capture events of the blaVIM-1 gene or different IS26-mediated plasmid rearrangements from a common ancestor may explain plasmid variations.

Prevalence and risk factors for colonisation and infection with carbapenem-resistant Enterobacterales in intensive care units: A prospective multicentre study

OBJECTIVES

This study aimed to investigate the prevalence and risk factors for carbapenem-resistant Enterobacterales colonisation/infection at admission and acquisition among patients admitted to the intensive care unit.

RESEARCH METHODOLOGY/DESIGN

A prospective and multicentre study.

SETTING

This study was conducted in 24 intensive care units in Anhui, China.

MAIN OUTCOME MEASURES

Demographic and clinical data were collected, and rectal carbapenem-resistant Enterobacterales colonisation was detected by active screening. Multivariate logistic regression models were used to analyse factors associated with colonisation/infection with carbapenem-resistant Enterobacterales at admission and acquisition during the intensive care unit stay.

RESULTS

There were 1133 intensive care unit patients included in this study. In total, 5.9% of patients with carbapenem-resistant Enterobacterales colonisation/infection at admission, and of which 56.7% were colonisations. Besides, 8.5% of patients acquired carbapenem-resistant Enterobacterales colonisation/infection during the intensive care stay, and of which 67.6% were colonisations. At admission, transfer from another hospital, admission to an intensive care unit within one year, colonisation/infection/epidemiological link with carbapenem-resistant Enterobacterales within one year, and exposure to any antibiotics within three months were risk factors for colonisation/infection with carbapenem-resistant Enterobacterales. During the intensive care stay, renal disease, an epidemiological link with carbapenem-resistant Enterobacterales, exposure to carbapenems and beta-lactams/beta-lactamase inhibitors, and intensive care stay of three weeks or longer were associated with acquisition.

CONCLUSION

The prevalence of colonisation/infection with carbapenem-resistant Enterobacterales in intensive care units is of great concern and should be monitored systematically. Particularly for the 8.5% prevalence of carbapenem-resistant Enterobacterales acquisition during the intensive care stay needs enhanced infection prevention and control measures in these setting. Surveillance of colonisation/infection with carbapenem-resistant Enterobacterales at admission and during the patient's stay represents an early identification tool to prevent further transmission of carbapenem-resistant Enterobacterales.

IMPLICATIONS FOR CLINICAL PRACTICE

Carbapenem-resistant Enterobacterales colonization screening at admission and during the patient's stay is an important tool to control carbapenem-resistant Enterobacterales spread in intensive care units.

Rapid, simple multi-locus variable number tandem repeat analysis: a reliable tool for Klebsiella pneumoniae outbreak screening

BACKGROUND

Klebsiella pneumoniae causing nosocomial infections is increasingly multi-drug-resistant. Rapid and efficient typing tools are required for monitoring.

AIM

To assess a simple, rapid (<5 h) multiplex polymerase chain reaction method based on multi-locus variable number tandem repeat analysis (MLVA) as a screening tool to determine whether or not K. pneumoniae strains are related.

METHODS

The global discriminatory power of the method was assessed on 72 unrelated K. pneumoniae isolates, including community carriage isolates, highly virulent strains causing liver abscess, and extended-spectrum beta-lactamase- and carbapenemase-producing strains. Suspected related strains from a suspected outbreak and a relapsed meningitis case were also studied. MLVA results were compared with whole-genome sequencing (WGS) analysis and multi-locus sequence typing (MLST).

FINDINGS

MLVA and MLST had similar discriminatory power, each distinguishing 54 profiles among the 72 unrelated isolates (Hunter-Gaston index 0.989). Each strain belonging to one sequence type (ST) or ST complex had its own MLVA type, with few exceptions. Two strains of ST268 and ST1119 shared the same MLVA profile, and two unrelated strains of ST307, ST86, ST45 and ST37 exhibited two different MLVA types each. Moreover, investigation of seven grouped cases of K. pneumoniae neonatal sepsis pointed to strong suspicion of a common source for five isolates, while two isolates with a different MLVA profile were excluded from this cluster.

CONCLUSION

The MLVA approach is a useful, rapid and reliable tool for epidemiological investigation requiring only basic molecular biology equipment, and permits identification of sporadic isolates that are not part of an outbreak. However, analysis of strains sharing the same MLVA type by a highly discriminatory technique, such as WGS, remains necessary.

Genomic tracking and precise control of Klebsiella pneumoniae transmission in a newly established hospital: a prospective molecular epidemiological study

OBJECTIVES

Carbapenem-resistant Klebsiella pneumoniae (CRKP) pose an emerging clinical threat. We investigated its introduction and transmission in a new hospital, evaluating the effect of whole-genome sequencing (WGS) as an infection control measure.

METHODS

Based on WGS of identified K. pneumoniae (Kpn) strains, a prospective molecular epidemiological study of nosocomial transmission of CRKP in a newly established Chinese hospital was conducted.

RESULTS

Between September 2018 and August 2020, 206 Kpn strains were isolated, including 180 CRKP, from 152 patients. The first imported and nosocomial transmission cases were recorded in December 2018 and April 2019, respectively. Overall, 22 nosocomial transmission clusters involving 85 patients were identified, among which 5 were large-size clusters comprising 5-18 patients. Index cases of the large-size clusters were more likely associated with lower Glasgow Coma Scale scores than those of small-size clusters. Furthermore, results of multivariable logistic regression indicated that Kpn tended to transmit more among patients in the ICU [adjusted odds ratio (aOR) = 4.96, 95% confidence interval (CI) 1.97-13.47] and those infected with a ST11 strain (aOR = 8.04, 95% CI 2.51-29.53) or tetracycline-resistant strains (aOR = 17.63, 95% CI 6.32-57.32). However, transmission was less likely in strains bearing the rmpA gene (aOR = 0.12, 95% CI 0.03-0.37). The rate of nosocomial CRKP cases decreased by 2.25 with the intervention of WGS-based infection control.

CONCLUSIONS

Kpn transmission in the newly established hospital originated from several imported cases. Rates of nosocomial CRKP infection were reduced considerably through precise infection control measures.

GraphSNP: an interactive distance viewer for investigating outbreaks and transmission networks using a graph approach

BACKGROUND

Cluster and transmission analysis utilising pairwise SNP distance are increasingly used in genomic epidemiological studies. However, current methods are often challenging to install and use, and lack interactive functionalities for easy data exploration.

RESULTS

GraphSNP is an interactive visualisation tool running in a web browser that allows users to rapidly generate pairwise SNP distance networks, investigate SNP distance distributions, identify clusters of related organisms, and reconstruct transmission routes. The functionality of GraphSNP is demonstrated using examples from recent multi-drug resistant bacterial outbreaks in healthcare settings.

CONCLUSIONS

GraphSNP is freely available at https://github.com/nalarbp/graphsnp . An online version of GraphSNP, including demonstration datasets, input templates, and quick start guide is available for use at https://graphsnp.fordelab.com .

Outbreak report of polymyxin-carbapenem-resistant Klebsiella pneumoniae causing untreatable infections evidenced by synergy tests and bacterial genomes

Polymyxin-carbapenem-resistant Klebsiella pneumoniae (PCR-Kp) with pan (PDR)- or extensively drug-resistant phenotypes has been increasingly described worldwide. Here, we report a PCR-Kp outbreak causing untreatable infections descriptively correlated with bacterial genomes. Hospital-wide surveillance of PCR-Kp was initiated in December-2014, after the first detection of a K. pneumoniae phenotype initially classified as PDR, recovered from close spatiotemporal cases of a sentinel hospital in Rio de Janeiro. Whole-genome sequencing of clinical PCR-Kp was performed to investigate similarities and dissimilarities in phylogeny, resistance and virulence genes, plasmid structures and genetic polymorphisms. A target phenotypic profile was detected in 10% (12/117) of the tested K. pneumoniae complex bacteria recovered from patients (8.5%, 8/94) who had epidemiological links and were involved in intractable infections and death, with combined therapeutic drugs failing to meet synergy. Two resistant bacterial clades belong to the same transmission cluster (ST437) or might have different sources (ST11). The severity of infection was likely related to patients' comorbidities, lack of antimicrobial therapy and predicted bacterial genes related to high resistance, survival, and proliferation. This report contributes to the actual knowledge about the natural history of PCR-Kp infection, while reporting from a time when there were no licensed drugs in the world to treat some of these infections. More studies comparing clinical findings with bacterial genetic markers during clonal spread are needed.

Epidemiological and Molecular Characteristics of bla NDM-1 and bla KPC-2 Co-Occurrence Carbapenem-Resistant Klebsiella pneumoniae

Objective

Carbapenem-resistant Klebsiella pneumoniae (CRKP) has emerged and spread worldwide. It can usually cause a serious threat complicating treatment options in clinical settings. However, treatment options are limited. The present study investigates the prevalence and genetic characteristics of bla _NDM-1 and bla _KPC-2 co-harboring clinical isolates of Klebsiella pneumoniae.

Methods

In this study, Multiplex polymerase chain reaction (PCR) was performed to detect the carbapenem-resistant genes, and the broth microdilution method was used to determine the minimum inhibitory concentrations (MICs) of antibacterial drugs. The transferability of carbapenem-resistant phenotypes was examined using filter mating assays. Overall, we used Illumina sequencing to evaluate the epidemiological and molecular characteristics of bla _NDM-1 and bla _KPC-2 (genes encoding carbapenemase) co-occurrence in CRKP strains.

Results

All strains exhibited resistance to carbapenems and other antibiotics. However, they were still susceptible to polymyxin E. Among them, 18 isolates were positive for bla _KPC-2, bla _NDM-1, and multiple virulence determinants, such as genes encoding the virulence factor aerobactin, yersiniabactin, and the regulator of the mucoid phenotype (rmpA and rmpA2). Whole genome sequencing revealed that the 18 CRKP strains belonged to ST11 and capsular serotype KL64, and could be grouped into two evolutionary branches. Furthermore, these strains displayed hypervirulence potential since all of them carried pLVPK-like plasmid.

Conclusion

These findings suggested that ST11-KL64 CRKP strains are major threats in terms of nosocomial infections in this hospital. Hence, new strategies should be urgently developed to monitor, diagnose, and treat this high-risk CRKP clone.

Infection prevention and control strategies against carbapenem resistant Enterobacteriaceae - a systematic review

Background

Antimicrobial resistance is exponentially worsening, and the spread of prevalent carbapenem resistant Enterobacteriaceae (CRE) is a major contributor to this global concern. Infection prevention and control strategies are increasingly consolidated key tools to control this worldwide problem.

Aim

To identify, collect and analyse available evidence regarding the impact of infection prevention and control strategies on prevalent CRE dissemination.

Methods

Pubmed®, Scopus® and Web of Science® were searched systematically for articles published between 1th January 2017 and 30th June 2020, guided by the research question 'What are the most effective and efficient strategies to prevent and control infection/colonisation caused by Carbapenem resistant Escherichia coli and Carbapenem resistant Klebsiella pneumoniae?'.

Findings

Eleven thousand six hundred and thirty-five publications were found, but after applying the inclusion and exclusion criteria, only 30 were selected. The majority of reviewed studies (n = 24) were performed in outbreak situations, 26 studies occurred in acute care units and of those, 17 in intensive care units . From the set of implemented infection prevention and control measures, in 29 studies surveillance cultures were applied, in 23 studies patients were isolated or cohorted and, in general, all described the implementation of standard and contact precaution measures.

Conclusion

This systematic review underlines the importance of infection prevention and control strategies in CRE dissemination, standing out the need of further studies outside outbreak and intensive care units contexts. Investment increments and training and educating of all involved are also important contributors to shift this problem, but still with relevant gaps in their implementation, in all types of care units, that need to be addressed.

Whole genome sequencing reveals hidden transmission of carbapenemase-producing Enterobacterales

Carbapenemase-producing Enterobacterales (CPE) infection control practices are based on the paradigm that detected carriers in the hospital transmit to other patients who stay in the same ward. The role of plasmid-mediated transmission at population level remains largely unknown. In this retrospective cohort study over 4.7 years involving all multi-disciplinary public hospitals in Singapore, we analysed 779 patients who acquired CPE (1215 CPE isolates) detected by clinical or surveillance cultures. 42.0% met putative clonal transmission criteria, 44.8% met putative plasmid-mediated transmission criteria and 13.2% were unlinked. Only putative clonal transmissions associated with direct ward contact decreased in the second half of the study. Both putative clonal and plasmid-mediated transmission associated with indirect (no temporal overlap in patients’ admission period) ward and hospital contact did not decrease during the study period. Indirect ward and hospital contact were identified as independent risk factors associated with clonal transmission. In conclusion, undetected CPE reservoirs continue to evade hospital infection prevention measures. New measures are needed to address plasmid-mediated transmission, which accounted for 50% of CPE dissemination.

Carbapenemase-producing Enterobacterales cause healthcare-associated infections but modes of transmission are not well understood. Here, the authors find evidence of transmission without direct patient contact, indicating presence of undetected environmental reservoirs, whilst half of the transmission events are likely due to plasmid-mediated transmission.

Sequence-Based Genomic Analysis Reveals Transmission of Antibiotic Resistance and Virulence among Carbapenemase-Producing Klebsiella pneumoniae Strains

Carbapenemase-producing Klebsiella pneumoniae (CP-Kpn) are a major concern for nosocomial infections. We previously reported an intensive care unit (ICU) outbreak of CP-Kpn. This study investigated the transmission pattern and genetic characteristic of CP-Kpn in the hospital during the outbreak period. Whole-genome sequencing was retrospectively performed on 173 CP-Kpn isolates. Pairwise single-nucleotide polymorphism (SNP) distances were calculated to determine SNP thresholds for clustering. Plasmids and mobile genome elements (MGEs) were identified through short- and long-read sequencing. Strains were classified into three groups, sequence type 11 (ST11) (86.12%), ST15 (9.83%), and other ST. An SNP threshold of 16 revealed a 66.47% clustering rate. ICU admission and meropenem use proportions were significantly higher in clustered patients than in unique patients. MGE distribution was consistent with the phylogenetic tree. Of the isolates, 53.18% were CP-Kpn with hypervirulence genes. We identified five plasmids carrying virulence genes, and four of them have not been previously reported. Clonal transmission was the main cause of CP-Kpn infections in the hospital. Multidrug resistance genes and MGE variations were correlated with clustering. Finally, four novel plasmids carrying virulence genes were identified. The findings highlight the control of CR-Kpn transmission through prevention measures to reduce nosocomial infections. IMPORTANCE In this study, we combined genomic and epidemiological analyses and defined an optimal cutoff value for SNP difference that could be used to aid investigation in tertiary hospital in China. We revealed clonal transmission was the main cause of CP-Kpn infections in the hospital and identified four novel plasmids carrying virulence genes. Our results strongly suggested that dominant CP K. pneumoniae strains lead to outbreaks and described different evolutionary patterns of plasmids carrying multidrug resistance and virulence genes.

Dissemination of a single ST11 clone of OXA-48-producing Klebsiella pneumoniae within a large polyclonal hospital outbreak determined by genomic sequencing

The population structure of a set of OXA-48-producing Klebsiella pneumoniae isolates belonging to sequence type 11 (ST11 Kp-OXA) and obtained from two hospitals in Madrid in the period from 2012 to 2015 was studied by genome sequencing. Overall, 97 ST11 Kp-OXA isolates were sequenced and their population structure and demography were studied by Bayesian phylodynamic analysis using core-genome SNVs. In total, 92 isolates were from Hospital La Paz, 57 of them from two selected units. The remaining five isolates were from different units of Hospital Doce de Octubre. Altogether, 96 out of the 97 ST11 Kp-OXA isolates could be ascribed to a single lineage that evolved into three sublineages. Demographic inference showed an expansion of the ST11 Kp-OXA in the first half of 2013 in agreement with the registered incidences. Dated phylogeny showed transmission clusters within hospital wards, between wards and between hospitals. The ST11 Kp-OXA outbreak in Hospital La Paz was largely due to the expansion of a single clone that was transmitted between different units and to Hospital Doce de Octubre. This clone diverged into three sub-lineages and spread out following a mixed mode of neutral core-genome evolution with some features of antibiotic selection, frequent large deletions and plasmid loss and gain events.

Clonal spread of carbapenemase-producing Enterobacteriaceae in a region, China

Background

The increasing number of carbapenemase-producing Enterobacterales (CPE) has become a serious problem globally. This study aimed to elucidate their geographically epidemiological characteristics.

Methods

Resistance genes were identified by polymerase chain reaction (PCR) and sequencing. Bacterial genotyping was studied using multilocus sequence typing (MLST) and wzi typing. The transferability of carbapenemase genes was determined by a broth mating method. The relationships between the rates of antimicrobial consumption and the prevalence of CRE were performed by Pearson's or Spearman's correlation analyses.

Results

A total of 930 phenotypically confirmed carbapenem-resistant Enterobacterales (CRE) isolates collected from 19 hospitals were genotypically characterized. K. pneumoniae (KP) and E. coli isolates were 785 (85.14%) and 96 (10.41%) among 922 CPE isolates. Two major carbapenemase genes blaKPC-2 and blaNDM in CPE isolates accounted for 84.6% (n = 780) and 13.77% (n = 127). ST11 comprised 86.83% (633/729) of KPC-2 KP isolates. Different combinations of extended spectrum-β-lactamase (ESBL) genes of blaSHV, blaCTX, and blaTEM were found in KPC-2 producing KP isolates, and blaCTM-M-14/15, blaSHV-11/12 and blaTEM-1 were common ESBL genotypes. The wzi typing method could further subdivide ST11 KP group into at least five subgroups, among which wzi209 (69.83%, 442/633) was the most frequently isolated, followed by wzi141 (25.28%, 160/633). Conjugation assays showed that high conjugation rates were observed in CPE (15.24%, 32/210) for NDM plasmids, but relatively low (8.1%, 17/210) for KPC-2 plasmids. Different STs, different wzis and temperature could influence plasmid conjugation efficiency. No associations between the rates of antibiotics consumption and CPE prevalence were observed. The number of intra-hospital and inter-hospital transfers of CPE patients increased gradually from 18 (17.82%, 101) and 12 (11.88%, 101) in 2015 to 63 (30.73%, 205) and 51 (24.88%, 205) in 2018 (p = 0.016 and p = 0.008), respectively. Evidence-based measures could effectively reduce the prevalence of ST11-wzi209 clone but failed to control the dissemination of ST11-wzi141 KP clone.

Conclusions

Clonal spread of CPE, especially KPC-2 ST11 KP was the key factor contributing to the CPE increase in the region. Continued vigilance for the importations should be maintained. Coordinated regional interventions are urgently needed to reduce CPE threat.

Methods Combining Genomic and Epidemiological Data in the Reconstruction of Transmission Trees: A Systematic Review

In order to better understand transmission dynamics and appropriately target control and preventive measures, studies have aimed to identify who-infected-whom in actual outbreaks. Numerous reconstruction methods exist, each with their own assumptions, types of data, and inference strategy. Thus, selecting a method can be difficult. Following PRISMA guidelines, we systematically reviewed the literature for methods combing epidemiological and genomic data in transmission tree reconstruction. We identified 22 methods from the 41 selected articles. We defined three families according to how genomic data was handled: a non-phylogenetic family, a sequential phylogenetic family, and a simultaneous phylogenetic family. We discussed methods according to the data needed as well as the underlying sequence mutation, within-host evolution, transmission, and case observation. In the non-phylogenetic family consisting of eight methods, pairwise genetic distances were estimated. In the phylogenetic families, transmission trees were inferred from phylogenetic trees either simultaneously (nine methods) or sequentially (five methods). While a majority of methods (17/22) modeled the transmission process, few (8/22) took into account imperfect case detection. Within-host evolution was generally (7/8) modeled as a coalescent process. These practical and theoretical considerations were highlighted in order to help select the appropriate method for an outbreak.

Transmission Dynamics of Carbapenem-Resistant Klebsiella pneumoniae Sequence Type 11 Strains Carrying Capsular Loci KL64 and rmpA/rmpA2 Genes

The presence and dissemination of carbapenem-resistant Klebsiella pneumoniae (CRKP) often cause life-threatening infections worldwide, but the therapeutic option is limited. In this study, whole-genome sequencing (WGS) was applied to assess the epidemiological characteristics and transmission dynamics of CRKP isolates recovered from two fetal outbreaks of nosocomial infections. Between April 2016 and March 2018, a total of 70 isolates of K. pneumoniae were collected from sterile samples in a tertiary hospital in Hangzhou, China. The minimal inhibitory concentrations (MICs) of 21 antimicrobial agents were determined using the broth microdilution methods. Pulsed-field gel electrophoresis (PFGE) was performed on 47 CRKP isolates, and 16 clonally related isolates were further characterized by Illumina sequencing. In addition, the complete genome sequences of three representative isolates (KP12, KP36, and KP37) were determined by Oxford Nanopore sequencing. The K. pneumoniae isolates were recovered from patients diagnosed with pulmonary infection, cancer, or encephalopathy. For all CRKP isolates, PFGE separated three clusters among all strains. The most predominant PFGE cluster contained 16 isolates collected from patients who shared close hospital units and represented a potential outbreak. All 16 isolates showed an extremely high resistance level (≥87.5%) to 18 antimicrobials tested but remain susceptible to colistin (CST). Multiple antimicrobial resistance and virulence determinants, such as the carbapenem resistance gene bla_KPC-2, and genes encoding the virulence factor aerobactin and the regulator of the mucoid phenotype (rmpA and rmpA2), were observed in the 16 CRKP isolates. These isolates belonged to sequence type 11 (ST11) and capsular serotype KL64. A core genome single nucleotide polymorphism (cgSNP)-based phylogenetic analysis indicated that the 16 CRKP isolates could be partitioned into two separate clades (≤15 SNPs), suggesting the two independent transmission scenarios co-occurred. Moreover, a high prevalence of IncFIB/IncHI1B type virulence plasmid with the iroBCDN locus deleted, and an IncFII/IncR type bla_KPC-2-bearing plasmid was co-harbored in ST11-KL64 CRKP isolates. In conclusion, our data indicated that the nosocomial dissemination of ST11-KL64 CRKP clone is a potential threat to anti-infective therapy. The development of novel strategies for surveillance, diagnosis, and treatment of this high-risk CRKP clone is urgently needed.

Three challenging cases of infections by multidrug-resistant Serratia marcescens in patients admitted to intensive care units

The occurrence of multidrug-resistant Serratia marcescens strains represents a serious public health threat. The purpose here is to report three cases of carbapenem-resistant S. marcescens infections with unfavorable clinical outcomes and provide a molecular description of the antibiotic resistance determinants at a genomic level. We performed bacterial identification by VITEK 2 and MALDI-TOF. The minimal inhibitory concentrations of antimicrobials were determined according to the Clinical and Laboratory Standards Institute guidelines, except for tigecycline, for which they were determined using Etest strips. Preliminary screening for the presence of carbapenemases was performed by ertapenem hydrolysis using MALDI-TOF MS. Whole-genome sequencing was provided to identify genes responsible for virulence and antimicrobial resistance. Here we report three challenging cases of S. marcescens that were resistant to the most commonly used antibiotics. Otherwise, we performed a genome description, which includes several genes involved in the resistance and virulence. These cases illustrate serious infection due to multidrug-resistant organisms and the complexity of treatment. Our results highlight the need to evaluate isolates regularly during long-term hospital stay to achieve optimal quality of clinical care and thus improve patient outcomes.

On the island of Zanzibar people in the community are frequently colonized with the same MDR Enterobacterales found in poultry and retailed chicken meat

OBJECTIVES

Intestinal colonization with extended-spectrum cephalosporin-resistant (ESC-R) and colistin-resistant (CST-R) Enterobacterales (Ent) can be driven by contact with colonized animals and/or contamination of the food chain. We studied the ESC-R-Ent and COL-R-Ent colonizing poultry as well as contaminating chicken meat in Zanzibar (Tanzania). Results were compared with recently published data obtained from rectal swabs of people in the community.

METHODS

During June and July 2018, we collected poultry faecal material (n = 62) and retail chicken meat (n = 37) samples. ESC-R and CST-R strains were isolated implementing selective approaches and characterized with different molecular methods, including WGS coupled with core-genome analyses.

RESULTS

The prevalence of ESC-R-Ent and CST-R-Ent, respectively, were: 88.7% and 48.4% in poultry; and 43.2% and 18.9% in chicken meat. Overall, the following strains and main resistance mechanisms were found in the two settings: 69 ESC-R Escherichia coli (CTX-M-15 subgroup, 75%), 34 ESC-R Klebsiella pneumoniae (CTX-M-9 group, 54.5%), 24 non-ESC-R but CST-R E. coli (mcr-1, 95.8%) and 17 non-ESC-R but CST-R K. pneumoniae (D150G substitution in PhoQ). Several clones (differing by only 0-13 single nucleotide variants) were concomitantly and frequently found in human and non-human settings: mcr-1-carrying E. coli ST46; CTX-M-15-producing E. coli ST361; CTX-M-14-producing K. pneumoniae ST17; and CTX-M-15-producing K. pneumoniae ST1741.

CONCLUSIONS

This is one of the few studies that have assessed the occurrence of identical MDR Enterobacterales in human and non-human settings. The frequent human gut colonization observed in the community might be favoured by the spread of ESC-R-Ent and CST-R-Ent in poultry and chicken meat. Further studies with a One Health approach should be carried out to better investigate this phenomenon.

Realizing a learning health system through process, rigor and culture change

While many healthcare organizations strive to achieve the patient care benefits of being a learning health system (LHS), myriad challenges stand in the way of successful implementation. The reality of creating a true LHS requires top-to-bottom commitment to culture change with the necessary vision, leadership, and investment. The Center for Outcomes Research and Evaluation (CORE) is a multidisciplinary research unit embedded within a large, vertically integrated healthcare system in the southeastern United States. We used a two-pronged approach to: a) methodically recruit a team of experts, while generating early wins that demonstrated real success; and b) build relationships and buy-in across organizational leadership. Building out a team with diverse expertise created the ability to deploy pragmatic, data-driven research designs that fit seamlessly into real-world care delivery, resulting in agile study execution that aligns with health system timelines. Case study examples from hospital readmissions and antibiotic stewardship illustrate how our LHS operationalizes practice-informed research and research-informed practice. Lessons from this experience can serve as a blueprint for other healthcare systems or networks seeking to expand the promise of the LHS framework to improve health for patients and communities.

Risk factors for transmission of carbapenem-resistant Enterobacterales to healthcare personnel gloves and gowns in the USA

BACKGROUND

Hospitals are sources for acquisition of carbapenem-resistant Entero-bacterales (CRE), and it is believed that the contamination of healthcare personnel (HCP) hands and clothing play a major role in patient-to-patient transmission of antibiotic-resistant bacteria.

AIM

The aim of this study was to determine which HCP types, HCP-patient interactions, and patient characteristics are associated with greater transmission of CRE to HCP gloves and gowns in the hospital.

METHODS

This was a prospective observational cohort study that enrolled patients with recent surveillance or clinical cultures positive for CRE at five hospitals in four states in the USA. HCP gloves and gown were cultured after patient care. Samples were also obtained from patients' stool, perianal area, and skin of the chest and arm to assess bacterial burden.

FINDINGS

Among 313 CRE-colonized patients and 3070 glove and gown cultures obtained after patient care, HCP gloves and gowns were found to be contaminated with CRE 7.9% and 4.3% of the time, respectively. Contamination of either gloves or gowns occurred in 10.0% of interactions. Contamination was highest (15.3%) among respiratory therapists (odds ratio: 3.79; 95% confidence interval: 1.61-8.94) and when any HCP touched the patient (1.52; 1.10-2.12). Associations were also found between CRE transmission to HCP gloves or gown and: being in the intensive care unit, having a positive clinical culture, and increasing bacterial burden on the patient.

CONCLUSION

CRE transmission to HCP gloves and gown occurred frequently. These findings may inform evidence-based policies about what situations and for which patients contact precautions are most important.

Adaptive evolution of virulence and persistence in carbapenem-resistant Klebsiella pneumoniae

Among the most urgent public health threats is the worldwide emergence of carbapenem-resistant Enterobacteriaceae1-4, which are resistant to the antibiotic class of 'last resort'. In the United States and Europe, carbapenem-resistant strains of the Klebsiella pneumoniae ST258 (ref. 5) sequence type are dominant, endemic6-8 and associated with high mortality6,9,10. We report the global evolution of pathogenicity in carbapenem-resistant K. pneumoniae, resulting in the repeated convergence of virulence and carbapenem resistance in the United States and Europe, dating back to as early as 2009. We demonstrate that K. pneumoniae can enhance its pathogenicity by adopting two opposing infection programs through easily acquired gain- and loss-of-function mutations. Single-nucleotide polymorphisms in the capsule biosynthesis gene wzc lead to hypercapsule production, which confers phagocytosis resistance, enhanced dissemination and increased mortality in animal models. In contrast, mutations disrupting capsule biosynthesis genes impair capsule production, which enhances epithelial cell invasion, in vitro biofilm formation and persistence in urinary tract infections. These two types of capsule mutants have emerged repeatedly and independently in Europe and the United States, with hypercapsule mutants associated with bloodstream infections and capsule-deficient mutants associated with urinary tract infections. In the latter case, drug-tolerant K. pneumoniae can persist to yield potentially untreatable, persistent infection.

Progress towards the development of Klebsiella vaccines

Introduction: Klebsiella pneumoniae (KP) are a leading cause of healthcare-associated infections. The dramatic increase in microbial resistance to third-generation cephalosporin and carbapenem 'front line' antimicrobial agents and the paucity of new antimicrobials have left clinicians with few therapeutic options and resulted in increased morbidity and mortality. Vaccines may reduce the incidence of infections thereby reducing the necessity for antimicrobials and are not subject to antimicrobial resistance mechanisms. Areas covered: We review whole cell, subunit, capsular polysaccharide (CPS), O polysaccharide (OPS) and conjugate vaccines against KP infection, as well as alternative KP vaccine platforms. Expert opinion: Vaccine-induced antibodies to KP CPS have been protective in preclinical studies, but the number of CPS types (>77) makes vaccines against this virulence factor less feasible. Since four OPS serotypes account of ~80% of invasive KP infections and anti-OPS antibodies are also protective in preclinical studies, both OPS-based conjugate and multiple antigen presenting system (MAPS) vaccines are in active development. Vaccines based on other KP virulence factors, such as outer membrane proteins, type 3 fimbriae (MrkA) and siderophores are at earlier stages of development. Novel strategies for the clinical testing of KP vaccines need to be developed.

Caribbean multi-centre study of Klebsiella pneumoniae: whole-genome sequencing, antimicrobial resistance and virulence factors

The surveillance of antimicrobial-resistant isolates has proven to be one of the most valuable tools to understand the global rise of multidrug-resistant bacterial pathogens. We report the first insights into the current situation in the Caribbean, where a pilot project to monitor antimicrobial resistance (AMR) through phenotypic resistance measurements combined with whole-genome sequencing was set up in collaboration with the Caribbean Public Health Agency (CARPHA). Our first study focused on Klebsiella pneumoniae, a highly relevant organism amongst the Gram-negative opportunistic pathogens worldwide causing hospital- and community-acquired infections. Our results show that not only carbapenem resistance, but also hypervirulent strains, are circulating in patients in the Caribbean. Our current data does not allow us to infer their prevalence in the population. We argue for the urgent need to further support AMR surveillance and stewardship in this almost uncharted territory, which can make a significant impact on the reduction of antimicrobial usage. This article contains data hosted by Microreact (https://microreact.org).