Whole genome sequence of Klebsiella pneumoniae U25, a hypermucoviscous, multidrug resistant, biofilm producing isolate from India

Abstract BackgroundWith the wide use of florfenicol to prevent and treat the bacterial infection of domestic animals, the emergence of the florfenicol resistance bacteria is increasingly serious. It is very important to elucidate the molecular mechanism of the bacteria’s resistance to florfenicol. MethodsThe minimum inhibitory concentration (MIC) levels was determined by the agar dilution method, and polymerase chain reaction (PCR) was conducted to analyze the distribution of florfenicol resistance genes in 39 CoNS strains isolated from poultry and livestock animals and seafood. The whole genome sequence of one multidrug-resistant strain, Staphylococcus lentus H29, was characterized, and comparative genomics analysis of the resistance gene-related sequences was also performed. ResultsAs a result, the isolates from the animals showed a higher resistance rate (23/28, 82.1%) and much higher MIC levels of florfenicol than those from seafood. Twenty-seven animal isolates carried 37 florfenicol resistance genes (including 26 fexA , 6 cfr and 5 fexB genes), of which 1 carried a cfr gene, 16 carried a fexA gene, 5 carried both fexA and fexB genes and 5 carried both fexA and cfr genes. On the other hand, all 11 isolates from seafood were sensitive to florfenicol, and only 3 carried a fexA gene each. The whole genome sequence of S. lentus H29 was composed of a chromosome and two plasmids ( pH29-46 , pH29- 26) and harbored 11 resistance genes, including 6 genes [ cfr, fexA, ant(6)-Ia , aac A -aph D , mecA and mph(C) ] encoded on the chromosome, four genes [ cfr, fexA, aac A -aph D and tcaA ] on pH29-46 and one gene ( fosD ) on pH29-26. It was interested to find that the S. lentus H29 genome carried two identical copies of the gene arrays of radC - tnpABC - hp - fexA (5,671 bp) and IS 256 - cfr (2,690 bp), of which one copy of the two gene arrays was encoded on plasmid pH29-46, while the other was encoded on the chromosome. ConclusionsThe current study revealed the wide distribution of florfenicol resistance genes ( cfr, fexA and fexB ) in animal bacteria, and to the best of our knowledge, this is the first report of one CoNS strain carrying two identical copies of florfenicol resistance-related gene arrays.

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In vivo Emergence of Colistin Resistance in Carbapenem-Resistant Klebsiella pneumoniae Mediated by Premature Termination of the mgrB Gene Regulator

Frontiers in Microbiology ◽

10.3389/fmicb.2021.656610 ◽

2021 ◽

Vol 12 ◽

Author(s):

Yingying Kong ◽

Chao Li ◽

Hangfei Chen ◽

Wei Zheng ◽

Qingyang Sun ◽

...

Keyword(s):

Klebsiella Pneumoniae ◽

Genome Sequence ◽

Whole Genome Sequence ◽

Resistant Isolate ◽

Whole Genome ◽

Wild Type ◽

Colistin Resistance ◽

Putative Gene ◽

Carbapenem Resistant

Multidrug-resistant (MDR) Klebsiella pneumoniae is a severe threat to public health worldwide. Worryingly, colistin resistance, one of the last-line antibiotics for the treatment of MDR K. pneumoniae infection, has been increasingly reported. This study aims to investigate the emergence of evolved colistin resistance in a carbapenem-resistant K. pneumoniae isolate during colistin treatment. In this study, a pair of sequential carbapenem-resistant K. pneumoniae isolates were recovered from the same patient before and after colistin treatment, named KP1-1 and KP1-2, respectively. Antibiotic susceptibility testing was performed by the microdilution broth method. Whole genome sequencing was performed, and putative gene variations were analyzed in comparison of the genome sequence of both isolates. The bacterial whole genome sequence typing and source tracking analysis were performed by BacWGSTdb 2.0 server. Validation of the role of these variations in colistin resistance was examined by complementation experiments. The association between colistin resistance and the expression level of PhoP/PhoQ signaling system and its regulated genes was evaluated by quantitative real-time PCR (qRT-PCR) assay. Our study indicated that KP1-1 displayed extensively antibiotic resistant trait, but only susceptible to colistin. KP1-2 showed additional resistance to colistin. Both isolates belonged to Sequence Type 11 (ST11). The whole genome sequence analysis uncovered multiple resistance genes and virulence genes in both isolates. No plasmid-mediated mcr genes were found, but genetic variations in five chromosomal genes, especially the Gln30∗ alteration in MgrB, were detected in colistin-resistant isolate KP1-2. Moreover, only complementation with wild-type mgrB gene restored colistin susceptibility, with colistin MIC decreased from 32 to 1 mg/L. Expression assays revealed an overexpression of the phoP, phoQ, and pmrD genes in the mgrB-mutated isolate KP1-2 compared to the wild-type isolate KP1-1, confirming the MgrB alterations was responsible for increased expression levels of those genes. This study provides direct in vivo evidence that Gln30∗ alteration of MgrB is a critical region responsible for colistin resistance in K. pneumoniae clinical strains.

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Draft Whole-Genome Sequence of a Klebsiella pneumoniae Strain Isolated from a Marmoset in Thailand

Microbiology Resource Announcements ◽

10.1128/mra.00503-21 ◽

2021 ◽

Vol 10 (31) ◽

Author(s):

Komkiew Pinpimai ◽

Wijit Bunlunara ◽

Katriya Chankow ◽

Rachod Tantilertcharoen ◽

Pongthai Boonkam ◽

...

Keyword(s):

Klebsiella Pneumoniae ◽

Genome Sequence ◽

Whole Genome Sequence ◽

Whole Genome ◽

Negative Bacterium ◽

Gram Negative ◽

Content Type

Klebsiella pneumoniae is a Gram-negative bacterium that can cause infection in various kinds of animals and humans. Here, we report the genome sequence of K. pneumoniae isolated from a captive marmoset in Thailand.

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