Pyogenic liver abscess (PLA), which is particularly endemic in East Asia, is a relatively common and fatal infectious disease. Over the last 30-40 years, Klebsiella pneumoniae has replaced Escherichia coli as the dominant and overwhelming pathogen. To investigate the survival advantage of serotype K1 K. pneumoniae, we determined sequence types (STs), serotypes, and 11 virulence genes (allS, entB, irp2, iroN, iucA, fimH, mrkD, p-rmpA2, c-rmpA, p-rmpA, and peg-344). Virulence genes c-rmpA, p-rmpA, and p-rmpA2 in K. pneumoniae NTUH-K2044, which all confer hypercapsule and consequent hypervirulence, were deleted individually, and the consequent effects were evaluated. The lethality of various K1 K. pneumoniae strains was compared by using the Galleria mellonella model. In total, 31 K1 K. pneumoniae strains causing PLA and 30 causing non-PLA were identified. A significantly higher rate of c-rmpA was presented in PLA-derived K. pneumoniae strains than in non-PLA-derived strains. Similar ST23 (which dominates K1 strains) and string test-positive rates were observed in the two groups. Deletion of c-rmpA, p-rmpA, and p-rmpA2 individually did not confer significant effects on morphologies, such as positive string test, hypercapsule, and growth speed. Δc-rmpA presented weaker expressions of p-rmpA/p-rmpA2 than NTUH-K2044 and showed a higher expression of manC than Δp-rmpA and Δp-rmpA2. Three rmpAs conferred more virulence than one or two rmpAs, which presented an equally lethal effect in K1 K. pneumoniae. Klebsiella pneumoniae strains (H19 and H34) with the same genetic backgrounds except for siderophores showed equal virulence, but were less virulent than strain NTUH-K2044. Thus, the coexistence of c-rmpA with p-rmpA and p-rmpA2 enhances the lethality of K1 K. pneumoniae strains and the development of PLA. Excessive siderophores are not vital for the hypervirulence of K1 K. pneumoniae strains, although K1 strains usually harbour them on a molecular basis.
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http://dx.doi.org/10.1016/j.pathol.2023.07.007 | DOI Listing |
Infect Drug Resist
January 2024
Department of Laboratory Medicine, Gansu Provincial Hospital of Traditional Chinese Medicine, Lanzhou, Gansu, People's Republic of China.
Objective: To explore why serotype K2 accounts for a stable share in from pyogenic liver abscess (PLA).
Methods: Totally 15 K2 strains from PLA, 21 K2 from non-PLA, and 31 K1 from PLA were collected from China. Sequence typing, molecular serotyping, regular PCR, and lethality were performed.
Pathology
December 2023
School of Medical, Molecular and Forensic Sciences, Murdoch University, Murdoch, WA, Australia. Electronic address:
Pyogenic liver abscess (PLA), which is particularly endemic in East Asia, is a relatively common and fatal infectious disease. Over the last 30-40 years, Klebsiella pneumoniae has replaced Escherichia coli as the dominant and overwhelming pathogen. To investigate the survival advantage of serotype K1 K.
View Article and Find Full Text PDFJ Med Microbiol
June 2023
Medical Microbiology and Immunology, Faculty of Medicine, Assiut University, Assiut, Egypt.
Hypervirulent- (hvKP) is an evolving pathotype that is more virulent than the classical- (cKP) and causes serious fatal illnesses. Although there are few reports on hvKP isolated from Egyptian patients, the molecular characteristics and clonal relatedness of MDR-hvKP have not been adequately investigated. To investigate the microbiological and genetic characteristics as well as the epidemiology of hvKP induced ventilator-associated pneumonia (VAP).
View Article and Find Full Text PDFFront Cell Infect Microbiol
April 2023
Department of Laboratory Medicine, Huashan Hospital, Fudan University, Shanghai, China.
Purpose: To investigate the mechanisms of -induced pyogenic liver abscess (PLA).
Methods: Forty-three strains from PLAs and 436 from non-PLAs were collected. Their differences were compared for virulence genes and factors, sequence types, and serotypes.
Microbiology (Reading)
December 2011
Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.
Klebsiella pneumoniae community-acquired pyogenic liver abscess (PLA) is an emerging infectious disease. The rmpA gene (for regulator of mucoid phenotype A) has been reported to be associated with PLA in prevalence studies. NTUH-K2044, a K1 PLA isolate, carries three rmpA/A2 genes: two large-plasmid-carried genes (p-rmpA and p-rmpA2) and one chromosomal gene (c-rmpA).
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