Comparative analysis of the complete genome of KPC-2-producing Klebsiella pneumoniae Kp13 reveals remarkable genome plasticity and a wide repertoire of virulence and resistance mechanisms.
BACKGROUND
Klebsiella pneumoniae is an important opportunistic pathogen associated with nosocomial and community-acquired infections. A wide repertoire of virulence and antimicrobial resistance genes is present in K. pneumoniae genomes, which can constitute extra challenges in the treatment of infections caused by some strains. K. pneumoniae Kp13 is a multidrug-resistant strain responsible for causing a large nosocomial outbreak in a teaching hospital located in Southern Brazil. Kp13 produces K. pneumoniae carbapenemase (KPC-2) but is unrelated to isolates belonging to ST 258 and ST 11, the main clusters associated with the worldwide dissemination of KPC-producing K. pneumoniae. In this report, we perform a genomic comparison between Kp13 and each of the following three K. pneumoniae genomes: MGH 78578, NTUH-K2044 and 342.


RESULTS
We have completely determined the genome of K. pneumoniae Kp13, which comprises one chromosome (5.3 Mbp) and six plasmids (0.43 Mbp). Several virulence and resistance determinants were identified in strain Kp13. Specifically, we detected genes coding for six beta-lactamases (SHV-12, OXA-9, TEM-1, CTX-M-2, SHV-110 and KPC-2), eight adhesin-related gene clusters, including regions coding for types 1 (fim) and 3 (mrk) fimbrial adhesins. The rmtG plasmidial 16S rRNA methyltransferase gene was also detected, as well as efflux pumps belonging to five different families. Mutations upstream the OmpK35 porin-encoding gene were evidenced, possibly affecting its expression. SNPs analysis relative to the compared strains revealed 141 mutations falling within CDSs related to drug resistance which could also influence the Kp13 lifestyle. Finally, the genetic apparatus for synthesis of the yersiniabactin siderophore was identified within a plasticity region. Chromosomal architectural analysis allowed for the detection of 13 regions of difference in Kp13 relative to the compared strains.


CONCLUSIONS
Our results indicate that the plasticity occurring at many hierarchical levels (from whole genomic segments to individual nucleotide bases) may play a role on the lifestyle of K. pneumoniae Kp13 and underlie the importance of whole-genome sequencing to study bacterial pathogens. The general chromosomal structure was somewhat conserved among the compared bacteria, and recombination events with consequent gain/loss of genomic segments appears to be driving the evolution of these strains.
Pablo Ivan Pereira
PI
Ramos
Renata Christina
RC
Picão
Luiz Gonzaga Paula de
LG
Almeida
Nicholas Costa B
NC
Lima
Raquel
R
Girardello
Ana Carolina P
AC
Vivan
Danilo E
DE
Xavier
Fernando G
FG
Barcellos
Marsileni
M
Pelisson
Eliana C
EC
Vespero
Claudine
C
Médigue
Laboratório Nacional de Computação Científica, Petrópolis, Rio de Janeiro, Brazil. atrv@lncc.br.
Ana Tereza Ribeiro de
AT
Vasconcelos
Ana Cristina
AC
Gales
Marisa Fabiana
MF
Nicolás
D018829:Adhesins, Bacterial / Q000235:genetics / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002875:Chromosomes / Q000235:genetics / Q000378:metabolism; D024901:Drug Resistance, Multiple, Bacterial / Q000187:drug effects; D016680:Genome, Bacterial; D016623:Ion Pumps / Q000235:genetics / Q000378:metabolism; D007711:Klebsiella pneumoniae / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D008780:Methyltransferases / Q000235:genetics / Q000378:metabolism; D010957:Plasmids / Q000378:metabolism; D020641:Polymorphism, Single Nucleotide; D011113:Polymyxins / Q000494:pharmacology; D017422:Sequence Analysis, DNA; D014774:Virulence / Q000235:genetics; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism
D018829:Adhesins, Bacterial; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D016623:Ion Pumps; D011113:Polymyxins; D008780:Methyltransferases; D001618:beta-Lactamases