Genomic surveillance for hypervirulence and multi-drug resistance in invasive Klebsiella pneumoniae from south and southeast Asia
1Department of Infectious Diseases, Central Clinical School, Monash University, Melbourne, Victoria 3004, Australia
2Oxford University Clinical Research Unit, Hospital of Tropical Diseases, Ho Chi Minh City, Vietnam
3The Hospital of Tropical Diseases, Ho Chi Minh City, Vietnam
4Lao-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Laos.
5Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
6London School of Hygiene and Tropical Medicine, London, United Kingdom
7Department of Microbiology, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
8Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
9Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot 63110, Thailand.
10Cambodia Oxford Medical Research Unit, Angkor Hospital for Children, Siem Reap, Cambodia
11Lao-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
12Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
13Wellcome Trust Sanger Institute, Hinxton, Cambridge, United Kingdom
14The Department of Medicine, The University of Cambridge, Cambridge, United Kingdom
*corresponding author: kelly.wyres@monash.eduAbstract
Background
K. pneumoniae is a leading cause of blood stream infection (BSI). Strains producing extended spectrum beta-lactamases (ESBLs) or carbapenemases are considered global priority pathogens for which new treatment and prevention strategies are urgently required, due to severely limited therapeutic options. South and Southeast Asia are major hubs for antimicrobial resistant (AMR) K. pneumoniae, and also for the characteristically antimicrobial sensitive, community-acquired ‘hypervirulent’ strains. The emergence of hypervirulent AMR strains and lack of data on exopolysaccharide diversity pose a challenge for K. pneumoniae BSI control strategies worldwide.
Methods
We conducted a retrospective genomic epidemiology study of 365 BSI K. pneumoniae from seven major healthcare facilities across South and Southeast Asia, extracting clinically relevant information (AMR, virulence, K and O antigen loci) using Kleborate.
Findings
K. pneumoniae BSI isolates were highly diverse, comprising 120 multi-locus sequence types (STs) and 63 K-loci. ESBL and carbapenemase gene frequencies were 47% and 17%, respectively. The aerobactin synthesis locus (iuc), associated with hypervirulence, was detected in 28% of isolates. Importantly, 7% of isolates harboured iuc plus ESBL and/or carbapenemase genes. The latter represent genotypic AMR-virulence convergence, which is generally considered a rare phenomenon but was particularly common amongst South Asian BSI (17%). Of greatest concern, we identified seven novel plasmids carrying both iuc and AMR genes, raising the prospect of co-transfer of these phenotypes amongst K. pneumoniae.
Interpretation
South and Southeast Asia are high-risk regions for the emergence of AMR and convergent AMR-hypervirulent K. pneumoniae. Enhanced surveillance efforts, reporting STs, AMR and virulence information are urgently required to monitor this public health threat.
Funding
This work was supported by the Wellcome Trust (grant #206194 to Wellcome Sanger Institute) and the Bill and Melinda Gates Foundation, Seattle (grant OPP1175797 to KEH). KEH is supported by a Senior Medical Research Fellowship from the Viertel Foundation of Australia. DAB and PNN are supported by the Wellcome Trust.
Background
Klebsiella pneumoniae is now regarded globally by the World Health Organisation (WHO) and others, as a priority antimicrobial resistant (AMR) pathogen requiring new control strategies1. These include rapid identification and containment of high-risk AMR clones such as the carbapenemase-producing (CP) variants, augmented with vaccines, bacteriophages, or immunotherapies that target conserved surface antigens. However, K. pneumoniae is highly diverse, hindering the development of such strategies and our ability to study its molecular epidemiology in a short time frame.
This diverse bacterial species is generally associated with a range of differing community and healthcare-associated infections, but can be particularly problematic when the organisms gain access to sterile sites such as the cerebrospinal fluid, internal body cavities, and the bloodstream. Such infections are often characterised by rapid onset and multi-drug resistance (MDR), including resistance to third generation cephalosporins and/or carbapenems. Antimicrobials are the primary treatment strategy but options are severely limited by AMR. Concomitant with this are elevated mortality rates and treatment costs2.
K. pneumoniae is amongst the most common cause of bloodstream infections (BSI) in South (S) and Southeast (SE) Asia3–5. Infections in these locations are associated with a high mortality rate3, 6, yet K. pneumoniae is generally understudied in Asia and we have limited insight into the population structure and diversity of the organisms causing these infections in this global AMR epicentre. Available data suggest a heterogenous landscape; for example, CP strains are rare in SE Asia (<1-4%4, 7, 8) but common in S Asia (28-70%9, 10) and the prevalence of extended-spectrum beta-lactamase (ESBL) producing organisms varies from 12-79% in these regions3–5, 7, 9. Studies investigating ESBL and CP variants in S/SE Asia implicate CTX-M-15 as the most common ESBL type11, while NDM and OXA-48-like enzymes are the most commonly described carbapenemases10, 12.
Whilst the picture of K. pneumoniae pathogenesis is incomplete, isolates harbouring one or more key virulence determinants (including RmpA/RmpA2, which upregulate capsule expression; the colibactin genotoxin; and the yersiniabactin, aerobactin and salmochelin siderophores that promote systemic survival and dissemination13) are more commonly associated with invasive disease14, 15. Isolates that contain several of these determinants are associated with severe community-acquired invasive disease, often manifesting as liver abscess with bacteraemia. These are classified as ‘hypervirulent’ infections, they occur globally but are most commonly reported in SE Asia16 and are associated with clones ST23, ST86, and ST65. These clones typically express the K1/K2 capsules and are generally susceptible to most antimicrobials. However, the last few years have seen increasing reports of ‘convergent’ K. pneumoniae that are both hypervirulent (carrying the iuc aerobactin locus, which is suggested to be the single most important feature of hypervirulent strains17) and MDR ESBL/carbapenemase producers. The majority of these reports represent sporadic isolations, but in 2017 Gu and colleagues reported an outbreak in a Chinese hospital that caused five deaths18. Given the high burden of both MDR and hypervirulent K. pneumoniae infections, S/SE Asia likely represents a major global hub for phenotypic convergence, with the potential for outbreaks of invasive disease with severely limited treatment options.
Here we present a genomic epidemiology study of BSI K. pneumoniae from seven major healthcare facilities across S/SE Asia, leveraging a recently established genomic framework that incorporates rapid genotyping of clinically important features (ST or ‘clone’, AMR, virulence, capsule and lipopolysaccharide serotypes). The data are highly relevant to the design of K. pneumoniae control strategies, revealing a diverse population with high rates of AMR and virulence loci, and high prevalence of potentially dangerous convergent strains.
Methods
Setting
The following tertiary care hospitals were included: Patan Hospital, Kathmandu, Nepal; Christian Medical College Hospital, Vellore, India; Angkor Hospital for Children, Siem Reap, Cambodia; Mahosot Hospital, Vientiane, Lao PDR; The Hospital of Tropical Diseases, Ho Chi Minh City, Vietnam; Prince of Wales Hospital, Hong Kong. Isolates were also provided from healthcare inpatient departments serviced by the Shoklo Malaria Research Unit, Mae Sot, Thailand.
Bacterial isolates and culture
K. pneumoniae isolates obtained from blood cultures, following routine diagnostic protocols in each hospital laboratory and identified using biochemical testing (typically API-20E, bioMerieux), were included in the study. Isolates available for sequencing represented the following fractions of K. pneumoniae BSI collected at each site in participating years: India, 10%; Hong Kong, 17%; Vietnam, 20%; other sites, >90% (Figure 1).
DNA extractions, library preparation and sequencing
All isolates were cultured in LB broth at 37℃ overnight before DNA extraction using either Qiagen (Cambodia) or Promega kits (all other sites), as per manufacturer’s guidelines. Multiplexed Nextera XT libraries were sequenced on Illumina platforms, generating 150 bp paired-end reads. Eight isolates were selected for additional long-read sequencing using the Nanopore MinION R9 device as previously described19.
Genome assembly and genotyping
Illumina adapter sequences were removed and reads were quality trimmed using TrimGalore v0.4.4 (https://github.com/FelixKrueger/TrimGalore). Subsequently, draft de novo assemblies were generated using SPAdes v3.10.120 optimised with Unicycler v0.4.721. We excluded from further analysis nine low-quality genome assemblies outside the expected size range (5–6.5 Mbp).
Chromosomal multi-locus sequence typing (MLST), virulence locus and acquired resistance genes (excluding the core ampicillin resistance gene blaSHV and oqxAB efflux genes) were typed using Kleborate v0.3.0 (https://github.com/katholt/Kleborate). Surface capsule (K) and lipopolysaccharide (O) loci were identified using Kaptive22, 23. Novel K-loci were manually extracted using Bandage24, annotated using Prokka v1.13.325 before manual curation, and deposit in GenBank (accessions TBD). Where Kaptive was unable to confidently identify a K- locus due to fragmented genome assemblies (n=123), K-loci were predicted from wzi alleles if an unambiguous locus was associated to the allele in the K. pneumoniae BIGSdb (https://bigsdb.pasteur.fr/klebsiella/klebsiella.html). Ska v1.026 was used to calculate pairwise nucleotide differences between assemblies, and identify clusters of isolates for which the genomes differed by ≤100 single nucleotide variants (SNVs).
Hybrid Illumina-Nanopore assemblies were generated using Unicycler v0.4.7 as described previously19. Assemblies were annotated using Prokka v1.13.3 and iuc+ plasmid annotations were manually curated before depositing in GenBank (accessions TBD). Plasmid replicon types were identified using the PlasmidFinder database v2.027.
Isolate information, genotypes and genome data accessions are provided in Table S1. Genome assemblies, novel plasmid and K-locus sequences are also available in Figshare: https://doi.org/10.26180/5c67982956721.
Statistical analyses
Statistical analyses were performed using R v3.3.3 and data were visualised using ggplot2 v2.2.1. Given the disparity in sampling frames and small subgroup sample sizes it was not appropriate to test trends at country or year level. Statistical tests for regional differences in genetic features between K. pneumoniae populations (Table 1) were calculated using the subset of K. pneumoniae collected in overlapping two-year periods: S Asia region (Nepal and India; 2016-2017; n=102) vs SE Asia region (Cambodia, Laos, Thailand, Vietnam; 2015-2016, n=100).
Role of the funding source
No funding body played any role in the study design; collection, analysis or interpretation of data; preparation or the decision to submit this report for publication.
Results
The genomes of 393 presumptive K. pneumoniae BSI from seven countries across S/SE Asia were successfully sequenced (Figure 1A, Table S1). Twenty-eight genomes were identified as Enterobacteriaceae species outside of the K. pneumoniae species complex and were excluded from further analyses. Among the remaining 365 isolates, the majority (n=331, 91%) of organisms were confirmed to be K. pneumoniae. Among the regional comparator samples, these accounted for a higher proportion of genomes from S than SE Asia (98% vs 87%, p=0.011; see Table 1). The remaining isolates (detailed in Table S2) were K. quasipneumoniae subsp. similipneumoniae (n=20, 5.5%), K. variicola (n=9, 2.5%), and K. quasipneumoniae subsp. quasipneumoniae (n=5, 1.4%), which are not distinguishable from K. pneumoniae by standard microbiology methods14, 28.
The 331 K. pneumoniae were highly diverse and comprised 120 individual STs (Simpson’s diversity index=0.97), the majority (61%) of which were represented by a single isolate. Nevertheless, we observed four common STs that each accounted for >5% of the sequenced organisms: ST15 (n=37, 11%), ST23 (n=28, 8.5%), ST14 (n=22, 6.6%) and ST231 (n=17, 5.1%; Figure 1C). Amongst these, only ST15 was common across all sites, whereas ST23 was significantly associated with SE Asia (p=0.015) and ST14 and ST231 were both significantly associated with S Asia (p<0.01; see Table 1).
Predicted capsular (K) and O antigen serotypes
In this collection of invasive K. pneumoniae from BSI we detected 63 different K-loci including four novel loci designated KL162-165 (Simpson’s diversity index=0.95), the majority (67%) of these K-loci were found in ≤3 K. pneumoniae isolates each. The most common K-loci were KL1 (n=31; including 28 ST23), KL2 (n=27; numerous STs including ST14, ST25, ST65 and ST86), KL51 (n=23; including 17 ST231) and KL24 (n=20; including 17 ST15), together accounting for 28% of K. pneumoniae BSI (Figure 2). Saliently, while ST23 and ST231 were each associated with only a single K-locus (KL1 and KL51, respectively), the two other most common STs were each associated with multiple K-loci (ST15: KL24=17, KL112=9, KL10=3, KL62=2, KL19=2; ST14: KL64=7, KL2=6, KL157=1), as has been previously observed for ST25823. Ten of the 12 previously described O-antigen encoding loci were also detected (Simpson’s diversity index=0.80). Loci predicted to encode serotypes O1 and O2 were the most common, together accounting for 71% of K. pneumoniae BSI (Figure 2). Notably, the O3b locus, which is considered to be rare29, was detected here at 8% prevalence across sites (mean 7% per site, range 0-11%).
Acquired antimicrobial resistance determinants
Acquired AMR determinants were detected in 91% of K. pneumoniae genomes. The number of antimicrobial classes to which each isolate was predicted to be resistant showed a bimodal distribution (Figure 3A), with the majority of K. pneumoniae being MDR (acquired AMR genes conferring resistance to ≥3 drug classes; 63%) or possessing no acquired AMR genes (9%). The prevalence of MDR differed between sampling location and ranged from 22% in Hong Kong to 85% in India. MDR was significantly more prevalent among S Asian isolates than SE Asian isolates (81% vs 51%, p=0.0001; see Table 1). Consistently, the S Asian organisms had a significantly higher prevalence of fluoroquinolone, aminoglycoside and carbapenem resistance determinants than the SE Asian organisms (p<0.001 for each class; see Table 1).
The overall prevalence of ESBL genes amongst the K. pneumoniae isolates was 47% (n=157), but varied between study sites (22-75%; see Figure 3B). The majority of ESBL K. pneumoniae (90%) were predicted to be resistant to a further ≥3 alternative antimicrobial classes (median 7 additional classes). The most common ESBL genes were blaCTX-M-15 (n=120/157, 76%), blaCTX-M-27 (n=14/157, 9%) and blaCTX-M-14 (n=13/157, 8%); these were detected in diverse chromosomal STs (Table 2, Table S1). Twelve additional putative ESBL genes were also detected in 1-7 genomes each (see Table S1).
The overall prevalence of carbapenemase genes was 17% (n=57), again varying widely between sites (0-50%; Figure 3C). All isolates with a carbapenemase gene were also MDR, with predicted resistance to a median of six additional drug classes. The most common carbapenemases were the OXA-48-like blaOXA-232 (n=36/57; 63%) and the metallo- betalactamase blaNDM-1 (n=18/57; 32%, including four genomes that also carried blaOXA-232); again these were each detected in a diverse set of STs (Table 2, Table S1). Five other carbapenemase genes were detected in 1-4 genomes each (see Table S1); blaKPC was not detected. Details of ESBL/CP K. pneumoniae STs identified at each site, including their specific enzymes, are shown in Table 2. Notably ST15 carrying blaCTX-M-15 were identified at all sites except Thailand (n=4 genomes), and occasionally also harboured the carbapenemases blaNDM-1 or blaOXA-232.
Acquired virulence determinants
Similarly we identified genes linked to invasive disease: the yersiniabactin locus (ybt) was present in 163 (49%) of the BSI K. pneumoniae, with the site prevalence ranging from 19- 67% (Figure 4A); no significant difference in ybt prevalence was observed between S and SE Asia (Table 1). Nine of the 14 known chromosomally integrated ybt mobile-genetic elements (ICEKps)15 and two ybt plasmids were detected. The most common were ICEKp5 (n=41), ICEKp4 (n=36) and ICEKp10 (also encoding colibactin, n=31), found across multiple study sites. The ICEKp10-positive samples included 25 in clonal group 23 (ST23 plus related STs), wherein ICEKp10 is a marker of the important globally distributed CG23-I sub-lineage30.
The iuc, iro and rmpA/rmpA2 loci, typically carried on virulence plasmids, were commonly detected (28% iuc, 21% iro, 18% rmpA 16% rmpA2; 14% with all four). The prevalence of iuc did not differ significantly between the S and SE Asian isolates, but iuc lineages and chromosomal STs of iuc-positive isolates were differentially distributed between the sampling sites (Figure 4B-C, Table 1 and 3). Iuc lineage 1 (iuc1, n=66) was widely distributed (Figure 4C) but more prevalent in SE Asia (27% vs 13% in S Asia, p=0.011; Table 1). Iuc1 is associated with the KpVP-1 virulence plasmid31 and was detected amongst 15 K. pneumoniae STs, most commonly those known to be associated with hypervirulent infections: ST23 (n=28), ST65 (n=7) and ST86 (n=7). Iuc5 (n=12) is associated with E. coli plasmids and was detected only in ST231 from India, while iuc2 (associated with KpVP-231) was detected in a single ST380 isolate from Vietnam. Iuc3 (n=13) was detected in SE Asia (Cambodia, Vietnam, Laos) and Hong Kong (Figure 4C), among eight distinct STs (Table S1). We selected four iuc3-positive isolates from Vietnam and Laos for long-read sequencing and found each harboured a distinct and novel FIBK/FII iuc3 plasmid (Table 4).
Genotypic convergence of antimicrobial resistance and virulence
While strains carrying either AMR or hypervirulence determinants are of concern, those carrying both pose the greatest potential public health threat. The ybt virulence locus was significantly associated with ESBL K. pneumoniae (OR 1.7, p=0.021) and CP K. pneumoniae (OR 3.2, p=0.0002). Ybt+ ESBL K. pneumoniae BSI were detected at all sites (Figure 5A) and exhibited a similar prevalence in both S and SE Asia (Table 1). Iuc, the most significant contributor to hypervirulence in K. pneumoniae17, 32, was present in 13% of ESBL K. pneumoniae BSI (vs 43% amongst non-ESBL; OR 0.2, p<0.0001) and 23% of CP K. pneumoniae (vs 30% amongst non-CP; OR 0.7, p=0.34). Overall prevalence of iuc+ ESBL K. pneumoniae was 6%. Iuc+ ESBL isolates were detected at five of the seven sampling locations (Figure 5A), and were more common in S than SE Asia (p<0.001, Table 1). Conversely, iuc+ CP K. pneumoniae BSI were detected only in India (n=12 ST231, 14% of all isolates from this location) and Nepal (n=1 ST15, 3%).
Convergent AMR-hypervirulent isolates (defined as organisms carrying iuc in addition to ESBL and/or carbapenemase genes) were seen across seven different STs circulating across this region, with the overall prevalence being 7.3% (Figure 5B, Table 3). Long-read sequencing of four representative isolates of different STs revealed four novel mosaic plasmids. Three of these plasmids (and the four iuc3 plasmids described above) harboured iuc plus AMR genes (1-10 AMR genes, encoding resistance to 10 distinct drug classes; see Table 4). Notably, one of these plasmids harboured iuc1, blaCTX-M-15, and eight additional AMR genes (plasmid pBA813_1 from isolate BA813, Table 4). While pBA813_1 was not predicted to encode the tra plasmid transfer machinery, the four iuc3 plasmids and one of the iuc1 plasmids (pBA6201_1, iuc1 plus five AMR genes) contained a complete tra operon suggesting that they are capable of conjugative transfer. Consistent with this, we detected a high degree of sequence similarity between the iuc3 plasmids carried by isolates of three distinct STs in Laos, supporting their dissemination within the local K. pneumoniae population.
Comparison of chromosomal ST, iuc lineage and AMR gene content indicate at least 9 distinct AMR-virulence convergence events in our sample (Table 3). These include four distinct AMR element acquisitions by previously described hypervirulent STs (three in ST23 from Vietnam, Laos and India; one in ST65 from Vietnam), four distinct virulence plasmid acquisitions by previously described MDR STs (one in ST15 from Nepal; one in ST11 from India; one in ST2096 from India; one in ST231 from India; plus one in ST45 from Hong Kong). Most of these organisms also harboured the additional virulence factors ybt, iro and rmpA/rmpA2 (Table 3), increasing the likelihood of hypervirulent phenotype.
Each AMR-hypervirulent strain was detected only at one site, with no evidence of dissemination between countries. However we identified six clusters of closely related K. pneumoniae strains (each separated by ≤100 SNVs) that were detected in different countries (four in multiple SE Asian countries; two in India plus Laos or Hong Kong), suggesting that regional spread of K. pneumoniae does occur (Table S1).
Discussion
This work represents the first broad genomic study of K. pneumoniae causing BSI in S/SE Asia and Hong Kong, regions that are facing a combination of community-acquired invasive hypervirulent K. pneumoniae, unregulated use of antimicrobials, and the emergence and spread of MDR pathogens.
Ominously, alongside the high prevalence of ESBL and carbapenemase genes, our data revealed high prevalence of known hypervirulence determinants with the iuc locus detected in 28% of all isolates included in this study, more than double the prevalence seen in previous studies focused outside of this region31. While the locus itself was common in both S and SE Asia, the distribution of iuc lineages differed (Table 1). Specifically, iuc1 (associated with the characteristic KpVp-1 virulence plasmid31) and iuc3 were more common in SE Asia where they were each detected among numerous distinct STs. This is consistent with their local dissemination, a finding supported by the discovery of four novel iuc3 encoding plasmids in these isolates. Of greatest concern was the detection of at least 9 distinct convergence events between AMR and hypervirulence (encompassing 7.3% of isolates) including seven novel dual AMR+iuc containing plasmids, which is almost twice the total number of convergent plasmids reported so far in other studies33–36. Given that our isolate collection represented a snapshot from seven diagnostic laboratories, we predict that these organisms are likely to be more widely distributed across Asia. As such, there is a need for enhanced K. pneumoniae surveillance to rapidly identify convergent AMR-hypervirulent strains and/or plasmids, and to monitor their spread in S/SE Asia and beyond.
In the light of these convergence events it is also clear that the diversity of K. pneumoniae causing BSI in S/SE Asia represents a significant challenge to therapy using existing or novel agents. Our study revealed a highly diverse set of isolates, both in terms of chromosomal STs and surface polysaccharide loci. The former is consistent with the hypothesis that the majority of BSIs originate from the patients’ personal gastrointestinal microbiota rather than from intra-hospital transmissions28. The latter is highly relevant to the design of vaccines or other interventions targeting K. pneumoniae capsules or lipopolysaccharide, which are considered of high importance in response to increasing prevalence of ESBL and CP strains, both of which were common in our sampling locations (47% and 17% of all isolates, respectively). From our sampling strategy we crudely estimate a non-cross-reactive capsule- targeted vaccine would need to include ≥16 serotypes in order to provide potential protection against >50% of the BSI K. pneumoniae isolates across these study sites. The 16 most common K-loci would cover 61% of all ESBL and 68% of all CP K. pneumoniae across S/SE Asia. Alternatively, we estimate that a completely immunising vaccine targeting O1, O2 and O3b would hypothetically protect against 79% of the BSI K. pneumoniae isolates in this study; equating to 79% of all ESBL-containing isolates and 70% of CP.
An important limitation of this work is that the data represents a convenience sample of K. pneumoniae BSI isolates identified by the participating diagnostic laboratories during routine activities during overlapping time periods, and combined retrospectively. This prevented statistical comparisons between individual sites, and should be considered with caution when extrapolating gene prevalence information to the broader K. pneumoniae population. We focussed on BSI, as this allowed for convenient and consistent retrospective identification of isolates associated with invasive disease for inclusion in the study. While this presentation arguably reflects the greatest clinical need, the siderophore virulence loci are known to be more prevalent in BSI compared to other types of infection14. In addition, we note that our inferences about AMR are based on genotypic information, which is highly predictive of AMR in K. pneumoniae but not perfectly correlated28, 37. Nevertheless, our analyses reveal valuable insights, and provide essential data to motivate future systematic studies and enhanced public health surveillance.
Our study represents a blueprint for genomic surveillance of emerging AMR pathogens in Asia and we urge the coordination of similar activities internationally. By rapidly detecting resistance and virulence genes in the context of clonal and surface antigen diversity, our approach provides critical information that can be used to simultaneously track the emergence and dissemination of clinically important variants, guide empirical antimicrobial therapy, and assess potential mechanisms and targets for containment and intervention strategies. In combination with rapid reporting and data sharing, this approach will permit researchers and public health professionals to recognize and control the growing public health threat of AMR K. pneumoniae.
Supporting information
Declaration of interests
The authors declare no conflicts of interest.
Acknowledgements
We would like to acknowledge and thank all staff involved in obtaining and processing the isolates including healthcare facility and laboratory staff at Patan Hospital, Kathmandu, Nepal; Christian Medical College Hospital, Vellore, India; Angkor Hospital for Children, Siem Reap, Cambodia; Mahosot Hospital, Vientiane, Lao PDR; The Hospital of Tropical Diseases, Ho Chi Minh City, Vietnam; Prince of Wales Hospital, Hong Kong; and Shoklo Malaria Research Unit, Thailand. We also thank the WSI Pathogen Informatics team for help with data management. This work was supported by the Wellcome Trust (grant #206194 to Wellcome Sanger Institute) and the Bill and Melinda Gates Foundation, Seattle (grant OPP1175797 to KEH). KEH is supported by a Senior Medical Research Fellowship from the Viertel Foundation of Australia. DAB and PNN are supported by the Wellcome Trust.
SUPPLEMENTARY TABLES
Table S1 (see spreadsheet): Sample information and genotyping results for all BSI Kp included in this study