The inactivation of the mgrB gene, which encodes a negative-feedback regulator of the PhoPQ signaling system, was recently shown to be a common mutational mechanism responsible for acquired polymyxin resistance among carbapenemase-producing Klebsiella pneumoniae strains from clinical sources. In this work, we show that mgrB mutants can easily be selected in vitro from different K. pneumoniae li...

OBJECTIVES Sublethal bactericidal antibiotics promote the formation of multidrug-tolerant persisters. Clinically, serum drug concentration increases gradually and reaches the peak level with high killing efficiency some time after administration. This study aimed to investigate if the initial low antibiotic concentration would promote persister formation in Klebsiella pneumoniae, an increasingl...

A clinical strain of Klebsiella pneumoniae was found to possess the chromosomal gene bla(SHV-56), encoding a new inhibitor-resistant beta-lactamase with a pI of 7.6. SHV-56 is derived from SHV-11 by the single substitution K234R. This mutation therefore evidences a new critical site for inhibitor resistance among SHV enzymes.

Hypervirulent variants of Klebsiella pneumoniae have been primarily reported in the Asian Pacific Rim, but they are spreading across the globe. We report the sequence of K. pneumoniae strain hvKP1, which caused liver-splenic abscesses in an otherwise healthy 24-year-old from Buffalo, NY, which will assist in determining why these variants are more pathogenic than "classic" K. pneumoniae strains.

We present the draft genome sequence of a Klebsiella pneumoniae carbapenemase (KPC)-producing sequence type 258 (ST258) K. pneumoniae strain, ST258_FL. Uniquely, strain ST258_FL harbors two copies of the blaKPC gene on the chromosome, one of which is integrated into a prophage.

We report here the complete genome sequence of Klebsiella pneumoniae strain HKUOPLC, isolated from a giant panda fecal sample collected from Ocean Park, Hong Kong. The complete genome of this bacterium may contribute to the discovery of efficient cellulose-degrading pathways.

We report here the draft genome sequence of Acinetobacter baumannii strain M3AC14-8, sequence type 2 (ST2), carrying a chromosomally carried blaKPC-2 gene. The draft genome consists of a total length of 4.11 Mbp and a G+C content of 39.25%.

We sequenced the first blaVIM-1-positive Klebsiella pneumoniae strain isolated in Singapore. The isolate belongs to multilocus sequence type 2542 (ST2542), and blaVIM-1 was the first gene in an integron that also contained aacA4, aphA15, aadA1, catB2, qacEdelta1, and sul1.

Plasmid pKP12226 was extracted and analyzed from a CTX-M-15-producing Klebsiella pneumoniae sequence type 11 (ST11) isolate collected in South Korea. The plasmid represents chimeric characteristics consisting of a pIP1206-like backbone and lysogenized phage P1-like sequences. It bears a resistance region that includes resistance genes to several antibiotics and is different from previously char...

Using aGalleria mellonellaanimal model, we compared the virulence of two sequence type 258 (ST258) KPC-producingKlebsiella pneumoniaestrains, which were representative of the two clades of this clonal lineage, with that of isogenic colistin-resistantmgrBmutants. With both strains, themgrBmutants did not exhibit modification in virulence. In theG. mellonellamodel, the clade 1 strain (capsular ty...