KPC-3–Producing Serratia marcescens Outbreak between Acute and Long-Term Care Facilities, Florida, USA

We describe an outbreak caused by Serratia marcescens carrying bla KPC-3 that was sourced to a long-term care facility in Florida, USA. Whole-genome sequencing and plasmid profiling showed involvement of 3 clonal lineages of S. marcescens and 2 bla KPC-3 -carrying plasmids. Determining the resistance mechanism is critical for timely implementation of infection control measures

Genomic epidemiology of carbapenem-resistant Klebsiella in Qatar: emergence and dissemination of hypervirulent Klebsiella pneumoniae sequence type 383 strains

The emergence of carbapenem-resistant, hypervirulent Klebsiella pneumoniae is a new threat to health care. We studied the molecular epidemiology of carbapenem-resistant Klebsiella pneumoniae isolates in Qatar using whole-genome sequence data. We also characterized the prevalence and genetic basis of hypervirulent phenotypes and established the virulence potential using a Galleria mellonella model. Of 100 Klebsiella isolates studied, NDM and OXA-48 were the most common carbapenemases. Core genome single-nucleotide polymorphism (SNP) analysis indicated the presence of diverse sequence types and clonal lineages; isolates belonging to Klebsiella quasipneumoniae subsp. quasipneumoniae sequence type 196 (ST196) and ST1416 may be disseminated among several health care centers. Ten K. pneumoniae isolates carried rmpA and/or truncated rmpA2, and 2 isolates belonged to KL2, indicating low prevalence of classical hypervirulent isolates. Isolates carrying both carbapenem resistance and hypervirulence genes were confined mainly to ST231 and ST383 isolates. One ST383 isolate was further investigated by MinION sequencing, and the assembled genome indicated that blaNDM was located on an IncHI1B-type plasmid (pFQ61_ST383_NDM-5) which coharbored several virulence factors, including the regulator of the mucoid phenotype (rmpA), the regulator of mucoid phenotype 2 (rmpA2), and aerobactin (iucABCD and iutA), likely resulting from recombination events. Comparative genomics indicated that this hybrid plasmid may be present in two additional Qatari ST383 isolates. Carbapenem-resistant, hypervirulent K. pneumoniae ST383 isolates pose an emerging threat to global health due to their simultaneous hypervirulence and multidrug resistance.Published versionThis research was funded by the Medical Research Centre (MRC) at Hamad Medical Corporation (HMC) (MRC-16134/16 to F.B.A.) and supported by the National Institutes of Health (R01AI104895, R21AI135522, and R21AI151362 to Y.D.)

Genomic classification and antimicrobial resistance profiling of Streptococcus pneumoniae and Haemophilus influenzae isolates associated with paediatric otitis media and upper respiratory infection

Abstract Acute otitis media (AOM) is the most common childhood bacterial infectious disease requiring antimicrobial therapy. Most cases of AOM are caused by translocation of Streptococcus pneumoniae or Haemophilus influenzae from the nasopharynx to the middle ear during an upper respiratory tract infection (URI). Ongoing genomic surveillance of these pathogens is important for vaccine design and tracking of emerging variants, as well as for monitoring patterns of antibiotic resistance to inform treatment strategies and stewardship. In this work, we examined the ability of a genomics-based workflow to determine microbiological and clinically relevant information from cultured bacterial isolates obtained from patients with AOM or an URI. We performed whole genome sequencing (WGS) and analysis of 148 bacterial isolates cultured from the nasopharynx (N = 124, 94 AOM and 30 URI) and ear (N = 24, all AOM) of 101 children aged 6–35 months presenting with AOM or an URI. We then performed WGS-based sequence typing and antimicrobial resistance profiling of each strain and compared results to those obtained from traditional microbiological phenotyping. WGS of clinical isolates resulted in 71 S. pneumoniae genomes and 76 H. influenzae genomes. Multilocus sequencing typing (MSLT) identified 33 sequence types for S. pneumoniae and 19 predicted serotypes including the most frequent serotypes 35B and 3. Genome analysis predicted 30% of S. pneumoniae isolates to have complete or intermediate penicillin resistance. AMR predictions for S. pneumoniae isolates had strong agreement with clinical susceptibility testing results for beta-lactam and non beta-lactam antibiotics, with a mean sensitivity of 93% (86–100%) and a mean specificity of 98% (94–100%). MLST identified 29 H. influenzae sequence types. Genome analysis identified beta-lactamase genes in 30% of H. influenzae strains, which was 100% in agreement with clinical beta-lactamase testing. We also identified a divergent highly antibiotic-resistant strain of S. pneumoniae, and found its closest sequenced strains, also isolated from nasopharyngeal samples from over 15 years ago. Ultimately, our work provides the groundwork for clinical WGS-based workflows to aid in detection and analysis of H. influenzae and S. pneumoniae isolates

IncX2 and IncX1-X2 Hybrid Plasmids Coexisting in a FosA6-Producing Escherichia coli Strain

IncX plasmids are receiving much attention as vehicles of carbapenem and colistin resistance genes, such as blaNDM, blaKPC, and mcr-1 Among them, IncX2 subgroup plasmids remain rare. Here, we characterized IncX2 and IncX1-X2 hybrid plasmids coexisting in a FosA6-producing Escherichia coli strain that were possibly generated as a consequence of recombination events between an R6K-like IncX2 plasmid and a pLN126_33-like IncX1 plasmid. Variable multidrug resistance mosaic regions were observed in these plasmids, indicating their potential to serve as flexible carriers of resistance genes. The diversity of IncX group plasmid backbones and accessory genes and the evolution of hybrid IncX plasmids pose a challenge in detecting and classifying them