1247. Molecular Epidemiology of Multi-drug Resistant Klebsiella pneumoniae and K. quasipneumoniae in Qatar

Background The molecular epidemiology of carbapenem-resistant Klebsiella species is not well investigated in Qatar. The objective of this work was to characterize the genetic context of carbapenemase-producing Klebsiella isolates recovered from clinical specimens. Methods Klebsiella isolates (n=100) were collected at 7 tertiary hospitals from 2015-2017. Identification and susceptibility testing were performed using MALDI-TOF MS and BD Phoenix system, respectively. Whole Genome Sequencing was performed on the Illumina NextSeq platform. Phylogenomic analysis, screening of resistance and virulence genes, and comparison of genetic environment of carbapenemase were carried out. Results Klebsiella pneumoniae was common (80), followed by K. quasipneumoniae (16), K. aerogenes (3) and K. oxytoca (1). The most prevalent were genes encoding NDM-1 (39), OXA-48 (20), OXA-232 (10) and OXA-181 (12). KPC-2 (3) and KPC-3 (2) were also identified; no carbapenemase-encoding genes could be identified in 15 isolates. Plasmid locations of 24 carbapenemase-encoding genes were determined; blaNDM-1 was localized on IncFII replicon, while blaOXA-181 and blaOXA-232 were commonly associated with ColKP3 plasmids. pOXA-48-like plasmid was detected in 17/20 isolates harboring blaOXA-48. blaKPC-3 was located on a contig with ‘traditional’ Tn4401a mobile genetic element. Sequence types (STs) were diverse and the ‘traditional’ clonal group (CG) 258 was rare. K. pneumoniae ST147 was predominant (13), followed by ST231 (7) and ST11 (5). Nine K. quasipneumoniae isolates belonged to ST196 and were highly clonal. The virulence loci such as yersiniabactin (ybt) and rmpA were not detected within the study’s K. quasipneumoniae isolates. Amongst K. pneumoniae, there were 50 ybt+ isolates; 8 isolates had rmpA, and of these, 3 belonged to ST383. K. pneumoniae serotype K2, the capsular serotype associated with invasive liver abscess syndrome, was detected in 5 isolates. Genetic relationship of carbapenem-resistant Klebsiella pneumoniae and K. quasipneumoniae isolates in Qatar inferred from core genome SNPs. The tree is overlaid with predicted antimicrobial resistance genes and virulence factors for each isolate. Conclusion The predominant carbapenemases among clinical Klebsiella species isolates in Qatar are NDM and OXA-48 like enzymes, disseminated through various plasmids. The detection of carbapenemase-producing isolate bearing rmpA and serotype K2 reflect the presence of both multidrug resistance and hypervirulence in K. pneumoniae. Disclosures Yohei Doi, MD, PhD, AstraZeneca (Speaker’s Bureau)bioMerieux (Consultant)FujiFilm (Advisor or Review Panel member, Speaker’s Bureau)Gilead (Consultant)GSK (Consultant)Meiji (Consultant)MSD (Consultant)Shionogi (Consultant) Yohei Doi, MD, PhD, Astellas (Individual(s) Involved: Self): Grant/Research Support; AstraZeneca (Individual(s) Involved: Self): Speakers’ bureau; bioMerieux (Individual(s) Involved: Self): Consultant, Speakers’ bureau; Chugai (Individual(s) Involved: Self): Consultant; Entasis (Individual(s) Involved: Self): Consultant; FujiFilm (Individual(s) Involved: Self): Advisor or Review Panel member; Gilead (Individual(s) Involved: Self): Consultant; GSK (Individual(s) Involved: Self): Consultant; Kanto Chemical (Individual(s) Involved: Self): Grant/Research Support; MSD (Individual(s) Involved: Self): Speaking Fee; Pfizer (Individual(s) Involved: Self): Grant/Research Support; Shionogi (Individual(s) Involved: Self): Grant/Research Support, Speakers’ bureau; Teijin Healthcare (Individual(s) Involved: Self): Speakers’ bureau; VenatoRx (Individual(s) Involved: Self): Consultant

Prevalence of Carbapenem-Resistant Klebsiella pneumoniae Co-Harboring blaKPC-Carrying Plasmid and pLVPK-Like Virulence Plasmid in Bloodstream Infections

This study aimed to characterize carbapenem-resistant Klebsiella pneumoniae (CR-KP) co-harboring blaKPC-2-carrying plasmid and pLVPK-like virulence plasmid. Between December 2017 and April 2018, 24 CR-KP isolates were recovered from 24 patients with bacteremia. The mortality was 66.7%. Pulsed-field gel electrophoresis and multilocus sequence typing results indicated four clusters, of which cluster A (n = 21, 87.5%) belonged to ST11 and the three remaining isolates (ST412, ST65, ST23) had different pulsotypes (cluster B, C, D). The blaKPC-2-carrying plasmids all belonged to IncFIIK type, and the size ranged from 100 to 390 kb. Nineteen strains (79.2%) had a 219-kb virulence plasmid possessed high similarity to pLVPK from CG43 with serotype K2. Two strains had a 224-kb virulence plasmid resembled plasmid pK2044 from K. pneumoniae NTUH-K2044(ST23). Moreover, three strains carried three different hybrid resistance- and virulence-encoding plasmids. Conjugation assays showed that both blaKPC-2 and rmpA2 genes could be successfully transferred to E. coli J53 in 62.5% of the strains at frequencies of 4.5 × 10−6 to 2.4 × 10−4, of which three co-transferred blaKPC-2 along with rmpA2 in large plasmids. Infection assays in the Galleria mellonella model demonstrated the virulence level of these isolates was found to be consistently higher than that of classic Klebsiella pneumoniae. In conclusion, CR-KP co-harboring blaKPC-2-carrying plasmid and pLVPK-like virulence plasmid were characterized by multi-drug resistance, enhanced virulence, and transferability, and should, therefore, be regarded as a real superbug that could pose a serious threat to public health. Hence, heightened efforts are urgently needed to avoid its co-transmission of the virulent plasmid (gene) and resistant plasmid (gene) in clinical isolates.

Virulence Differences in Hypervirulent Klebsiella pneumoniae between Isolates with Multi-Locus Sequence Type (MLST)-11 and Serotype K1 or K2 Strains

Background: Two different types of hypervirulent K. pneumoniae (HvKp), including MLST-11 or serotype K1/K2 strains, have been frequently described in recent studies. Although these two types of strains were described as HvKp, their virulence was not compared. In this study, an in vitro and in vivo approach was used to assess differences in virulence.Materials and Methods: A total of nine isolates, including one strain of serotype K1 isolate, two strains of serotype K2 isolates and six strains of ST11 isolates, were selected for this study. Phenotypic tests of virulence and associated genes were performed by string test, PCR, and in vitro models of serum resistance and phagocytosis.Results: Although serotype K2 strains and ST11 isolates had similar virulence gene profiles, the ST11 isolates showed less serum and phagocytic resistance than did serotype K1/K2 isolates. The mouse lethality test revealed that all 11 ST isolates were unable to cause lethality, even with > 107 CFU, while one serotype K1 and two serotype K2 showed an LD50 of £ 102 CFU. Aerobactin (or capsule knockout mutants) exhibited a decline in LD50 compared to the parental strain, while capsule mutants showed a more significant decrease in LD50.Conclusion: Since there was a significant difference in virulence levels between the two types of HvKp when assessed by in vitro and in vivo animal models, the designation "HvKp" may be a better term based on animal studies and to avoid confusion. Virulence and nonvirulence could be analysed in a relative manner, especially in comparison studies.

Outbreak of KPC-2 Carbapenem-Resistant Klebsiella pneumoniae ST76 and Carbapenem-Resistant K2 Hypervirulent Klebsiella pneumoniae ST375 Strains in Northeast China: Molecular and Virulent Characteristics

Background Carbapenem-resistant hypervirulent Klebsiella pneumoniae strains have recently come into existence worldwide; however, researchers in northeast China are not aware of their clinical features and molecular characteristics. Methods Here, the molecular and virulent characteristics of 44 carbapenem-resistant K. pneumoniae (CRKP) isolates collected from January 2015 to December 2017 were studied. Multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) were carried out to define the clonal relatedness among the isolates. PCR and capsular serotyping of the virulence-associated genes, as well as biofilm formation and serum complement-mediated killing assays, were employed to determine the virulent potential. The genomic features and associated mobile genetic elements of JmsCRE57 were detected by whole genome sequencing. Results The only positive isolate was JmsCRE57, which belonged to the ST375 serotype K2 that expressed uge, mrkD, fimH, kpn, aerobactin and rmpA virulence-associated genes and showed strong biofilm formation and serum sensitivity. Sequencing results showed that the JmsCRE57 genome mainly consisted of a circular chromosome, three antibiotic resistance plasmids and a virulent plasmid. The antibiotic resistance plasmid expressing blaKPC-2, blaCTX-M-15, aph(3'')-Ib, aph(6)-Id, qnrB1, aac(3)-IIa, aac(6')-Ib-cr, blaOXA-1, blaTEM-1B, catB4, sul2, dfrA14 and blaSHV-99. The virulent plasmid belonged to the IncHI1B group, which is mainly composed of mucoid phenotype genes and siderophore-associated genes. The remaining CRKP strains that expressed uge, fimH, mrkD and kpn virulence-associated genes were not successfully typed. Conclusion Our results provide new insights on the epidemiology of carbapenem-resistant K2 hypervirulent K. pneumoniae ST375 and CRKP ST76 strains in northeast China, which may help control their future outbreaks.

Outbreak of KPC-2 Carbapenem-Resistant Klebsiella pneumoniae ST76 and Carbapenem-Resistant K2 Hypervirulent Klebsiella pneumoniae ST375 Strains in Northeast China: Molecular and Virulent Characteristics

Background Carbapenem-resistant hypervirulent Klebsiella pneumoniae strains have recently come into existence worldwide; however, researchers in northeast China are not aware of their clinical features and molecular characteristics. Methods Here, the molecular and virulent characteristics of 44 carbapenem-resistant K. pneumoniae (CRKP) isolates collected from January 2015 to December 2017 were studied. Multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) were carried out to define the clonal relatedness among the isolates. PCR and capsular serotyping of the virulence-associated genes, as well as biofilm formation and serum complement-mediated killing assays, were employed to determine the virulent potential. The genomic features and associated mobile genetic elements of JmsCRE57 were detected by whole genome sequencing. Results The only positive isolate was JmsCRE57, which belonged to the ST375 serotype K2 that expressed uge, mrkD, fimH, kpn, aerobactin and rmpA virulence-associated genes and showed strong biofilm formation and serum sensitivity. Sequencing results showed that the JmsCRE57 genome mainly consisted of a circular chromosome, three antibiotic resistance plasmids and a virulent plasmid. The antibiotic resistance plasmid expressing blaKPC-2, blaCTX-M-15, aph(3'')-Ib, aph(6)-Id, qnrB1, aac(3)-IIa, aac(6')-Ib-cr, blaOXA-1, blaTEM-1B, catB4, sul2, dfrA14 and blaSHV-99. The virulent plasmid belonged to the IncHI1B group, which is mainly composed of mucoid phenotype genes and siderophore-associated genes. The remaining CRKP strains that expressed uge, fimH, mrkD and kpn virulence-associated genes were not successfully typed. Conclusion Our results provide new insights on the epidemiology of carbapenem-resistant K2 hypervirulent K. pneumoniae ST375 and CRKP ST76 strains in northeast China, which may help control their future outbreaks.

Outbreak of KPC-2 Carbapenem-Resistant Klebsiella pneumoniae ST76 and Carbapenem-Resistant K2 Hypervirulent Klebsiella pneumoniae ST375 Strains in Northeast China: Molecular and Virulent Characteristics

Background Carbapenem-resistant hypervirulent Klebsiella pneumoniae strains have recently come into existence worldwide; however, researchers in northeast China are not aware of their clinical features and molecular characteristics. Methods Here, the molecular and virulent characteristics of 44 carbapenem-resistant K. pneumoniae (CRKP) isolates collected from January 2015 to December 2017 were studied. Multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) were carried out to define the clonal relatedness among the isolates. PCR and capsular serotyping of the virulence-associated genes, as well as biofilm formation and serum complement-mediated killing assays, were employed to determine the virulent potential. The genomic features and associated mobile genetic elements of JmsCRE57 were detected by whole genome sequencing. Results The only positive isolate was JmsCRE57, which belonged to the ST375 serotype K2 that expressed uge, mrkD, fimH, kpn, aerobactin and rmpA virulence-associated genes and showed strong biofilm formation and serum sensitivity. Sequencing results showed that the JmsCRE57 genome mainly consisted of a circular chromosome, three antibiotic resistance plasmids and a virulent plasmid. The antibiotic resistance plasmid expressing blaKPC-2, blaCTX-M-15, aph(3'')-Ib, aph(6)-Id, qnrB1, aac(3)-IIa, aac(6')-Ib-cr, blaOXA-1, blaTEM-1B, catB4, sul2, dfrA14 and blaSHV-99. The virulent plasmid belonged to the IncHI1B group, which is mainly composed of capsular polysaccharide genes and siderophore-associated genes. The remaining CRKP strains that expressed uge, fimH, mrkD and kpn virulence-associated genes were not successfully typed. We also identified an isolate that expressed the alls gene. Conclusion Our results provide new insights on the epidemiology of carbapenem-resistant K2 hypervirulent K. pneumoniae ST375 and CRKP ST76 strains in northeast China, which may help control their future outbreaks.