Background: KPC-producing carbapenem-resistant Klebsiella pneumoniae (CRKP) infections are associated with high mortality; however, their virulence determinants are not well defined.
Methods: We investigated the virulence and plasmid transferability among KPC-containing K. pneumoniae isolates.
Results: KPC-2 and -3 were successfully conjugated and retained by a virulent K2 K. pneumoniae recipient isolate. Antimicrobial susceptibility testing showed KPC-2 and -3 donor strains were resistant to more than four classes of antibiotics while the K2 isolate was only initially resistant to ampicillin. After conjugation of KPC-2 and -3, the K2 K. pneumoniae transconjugants became resistant to all beta-lactams. Additionally, the KPC K2 K. pneumoniae transconjugants continued to retain its high serum resistance and murine lethality.
Conclusions: Conjugation and retainment of KPC by virulent K2 K. pneumoniae and the ability of the tranconjugants to maintain its high serum resistance and murine lethality after conjugation was demonstrated in this study. These findings are concerning for the potential of KPC-like genes to disseminate among virulent K. pneumoniae isolates.
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http://dx.doi.org/10.1186/1471-2334-14-176 | DOI Listing |
Virulence
December 2025
Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, USA.
This review summarizes key virulence factors associated with group B (GBS), a significant pathogen particularly affecting pregnant women, fetuses, and infants. Beginning with an introduction to the historical transition of GBS from a zoonotic pathogen to a prominent cause of human infections, particularly in the perinatal period, the review describes major disease manifestations caused by GBS, including sepsis, meningitis, chorioamnionitis, pneumonia, and others, linking each to specific virulence mechanisms. A detailed exploration of the genetic basis for GBS pathogenicity follows, emphasizing the roles of capsules in pathogenesis and immune evasion.
View Article and Find Full Text PDFBMC Microbiol
January 2025
Department of Respiratory Medicine, Capital Medical University, Beijing, China.
Background: The clinical outcomes and microbiological features of lower respiratory tract infections (LRTIs) caused by hypervirulent Klebsiella pneumoniae (hvKp) and classical Klebsiella pneumoniae (cKp) have not been well understood.
Methods: This study collected 287 non-repetitive Klebsiella pneumoniae isolates from 287 LRTI patients. All these strains underwent annotation for resistance and virulence factors, with 141 strains undergoing mouse infection experiments to assess their virulence.
Front Pediatr
January 2025
Department of Hematology, Aerospace Center Hospital, Beijing, China.
Introduction: Hypervirulent carbapenem-resistant Klebsiella pneumoniae (hv-CRKP) poses an increasing public health risk due to its high treatment difficulty and associated mortality, especially in bone marrow transplant (BMT) patients. The emergence of strains with multiple resistance mechanisms further complicates the management of these infections.
Methods: We isolated and characterized a novel ST11-KL64 hv-CRKP strain from a pediatric bone marrow transplantation patient.
Front Microbiol
January 2025
Department of Clinical Laboratory, Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders and Chongqing Key Laboratory of Pediatric Metabolism and Inflammatory Diseases, Chongqing, China.
capsular polysaccharide (CPS) is a crucial virulence factor for this pathogenic bacterium and is partially under transcriptional control. In this study, we used electrophoretic mobility shift assays and DNA enzyme footprinting to identified the hypothetical protein SPD_0410 as a negative regulator of locus. Our results showed that the D39Δ mutant strain exhibited significantly elevated CPS levels compared to the parental strain D39s.
View Article and Find Full Text PDFNat Commun
January 2025
Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, USA.
Bacteremia, a leading cause of death, generally arises after bacteria establish infection in a particular tissue and transit to secondary sites. Studying dissemination from primary sites by solely measuring bacterial burdens does not capture the movement of individual clones. By barcoding Klebsiella pneumoniae, a leading cause of bacteremia, we track pathogen dissemination following pneumonia.
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