scholarly journals Effects of iron on the growth, biofilm formation and virulence of Klebsiella pneumoniae causing liver abscess

2020 ◽  
Author(s):  
Tao Chen ◽  
Guofeng Dong ◽  
Siqin Zhang ◽  
Xiucai Zhang ◽  
Yajie Zhao ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Liver Abscess ◽  
Biofilm Formation ◽  
Iron Chelator ◽  
Infection Model ◽  
Invasive Infection ◽  
Liver Abscesses ◽  
Severe Infections ◽  
Lower Expression ◽  
Additional Iron

Abstract Background: Klebsiella pneumoniae is considered the most clinically relevant species of Enterobacteriaceae, known to cause severe infections including liver abscesses. To the best of our knowledge, a large proportion of iron in the human body is accumulated and stored in the liver. We hypothesize that increased iron availability is an important factor driving liver abscess formation and we therefore aim to understand the effects of iron on K. pneumoniae causing liver abscesses. Results: All tested K. pneumoniae clinical isolates, including those isolated from liver abscesses and other abdominal invasive infection sites, grew optimally when cultured in LB broth supplemented with 50 μM iron and exhibited the strongest biofilm formation ability under those conditions. Decreased growth and biofilm formation ability were observed in all tested strains when cultured with an iron chelator (P<0.05). The infection model of G. mellonella larvae indicated the virulence of liver abscess-causing K. pneumoniae (2/3) cultured in LB broth with additional iron was significantly higher than those under iron-restricted conditions (P<0.05). The relative expression levels of the four siderophore genes (iucB, iroB, irp1, entB) in K. pneumoniae strains isolated from liver abscesses cultured with additional iron were lower than those under iron-restricted conditions (P<0.05). Conclusions: It is suggested by our research that iron in the environment can promote growth, biofilm formation and enhance virulence of K. pneumoniae causing liver abscesses. A lower expression of siderophore genes correlates with increased virulence of liver abscess-causing K. pneumoniae. Further deeper evaluation of these phenomena is warranted.

scholarly journals Effects of iron on the growth, biofilm formation and virulence of Klebsiella pneumoniae causing liver abscess

2020 ◽  
Author(s):  
Tao Chen ◽  
Guofeng Dong ◽  
Siqin Zhang ◽  
Xiucai Zhang ◽  
Yajie Zhao ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Liver Abscess ◽  
Biofilm Formation ◽  
Iron Chelator ◽  
Infection Model ◽  
Invasive Infection ◽  
Liver Abscesses ◽  
Severe Infections ◽  
Lower Expression ◽  
Additional Iron

Abstract Background: Klebsiella pneumoniae is considered the most clinically relevant species of Enterobacteriaceae, known to cause severe infections including liver abscesses. To the best of our knowledge, a large proportion of iron in the human body is accumulated and stored in the liver. We hypothesize that increased iron availability is an important factor driving liver abscess formation and we therefore aim to understand the effects of iron on K. pneumoniae causing liver abscesses. Results: All tested K. pneumoniae clinical isolates, including those isolated from liver abscesses and other abdominal invasive infection sites, grew optimally when cultured in LB broth supplemented with 50 μM iron and exhibited the strongest biofilm formation ability under those conditions. Decreased growth and biofilm formation ability were observed in all tested strains when cultured with an iron chelator (P<0.05). The infection model of G. mellonella larvae indicated the virulence of liver abscess-causing K. pneumoniae (2/3) cultured in LB broth with additional iron was significantly higher than those under iron-restricted conditions (P<0.05). The relative expression levels of the four siderophore genes (iucB, iroB, irp1, entB) in K. pneumoniae strains isolated from liver abscesses cultured with additional iron were lower than those under iron-restricted conditions (P<0.05). Conclusions: It is suggested by our research that iron in the environment can promote growth, biofilm formation and enhance virulence of K. pneumoniae causing liver abscesses. A lower expression of siderophore genes correlates with increased virulence of liver abscess-causing K. pneumoniae. Further deeper evaluation of these phenomena is warranted.

scholarly journals Effects of iron on the growth, biofilm formation and virulence of Klebsiella pneumoniae causing liver abscess

2020 ◽  
Author(s):  
Tao Chen ◽  
Guofeng Dong ◽  
Siqin Zhang ◽  
Xiucai Zhang ◽  
Yajie Zhao ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Liver Abscess ◽  
Biofilm Formation ◽  
Iron Chelator ◽  
Infection Model ◽  
Invasive Infection ◽  
Liver Abscesses ◽  
Severe Infections ◽  
Lower Expression ◽  
Additional Iron

Abstract Background: Klebsiella pneumoniae is considered the most clinically relevant species of Enterobacteriaceae, known to cause severe infections including liver abscesses. To the best of our knowledge, a large proportion of iron in the human body is accumulated and stored in the liver. We hypothesize that increased iron availability is an important factor driving liver abscess formation and we therefore aim to understand the effects of iron on K. pneumoniae causing liver abscesses. Results: All tested K. pneumoniae clinical isolates, including those isolated from liver abscesses and other abdominal invasive infection sites, grew optimally when cultured in LB broth supplemented with 50 μM iron and exhibited the strongest biofilm formation ability under those conditions. Decreased growth and biofilm formation ability were observed in all tested strains when cultured with an iron chelator (P<0.05). The infection model of G. mellonella larvae indicated the virulence of liver abscess-causing K. pneumoniae (2/3) cultured in LB broth with additional iron was significantly higher than those under iron-restricted conditions (P<0.05). The relative expression levels of the four siderophore genes (iucB, iroB, irp1, entB) in K. pneumoniae strains isolated from liver abscesses cultured with additional iron were lower than those under iron-restricted conditions (P<0.05). Conclusions: It is suggested by our research that iron in the environment can promote growth, biofilm formation and enhance virulence of K. pneumoniae causing liver abscesses. A lower expression of siderophore genes correlates with increased virulence of liver abscess-causing K. pneumoniae. Further deeper evaluation of these phenomena is warranted.

scholarly journals Effects of iron on the growth, biofilm formation and virulence of Klebsiella pneumoniae causing liver abscess

2019 ◽  
Author(s):  
Tao Chen ◽  
Guofeng Dong ◽  
Siqin Zhang ◽  
Xiucai Zhang ◽  
Yajie Zhao ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Liver Abscess ◽  
Biofilm Formation ◽  
Iron Chelator ◽  
Infection Model ◽  
Invasive Infection ◽  
Iron Depletion ◽  
Liver Abscesses ◽  
Severe Infections ◽  
Additional Iron

Abstract Background: Klebsiella pneumoniae is considered the most clinically relevant species of Enterobacteriaceae, known to cause severe infections including liver abscesses. To the best of our knowledge, a large proportion of iron in the human body is accumulated and stored in the liver. We hypothesize that increased iron availability is an important factor driving liver abscess formation and we therefore aim to understand the effects of iron on K. pneumoniae causing liver abscesses. Results: All tested K. pneumoniae clinical isolates, including those isolated from liver abscesses and other abdominal invasive infection sites, grew optimally when cultured in LB broth supplemented with 50 μM iron and exhibited the strongest biofilm formation ability under those conditions. Decreased growth and biofilm formation ability were observed in all tested strains when cultured with an iron chelator (P<0.05). The infection model of G. mellonella larvae indicated the virulence of liver abscess-causing K. pneumoniae (2/3) cultured in LB broth with additional iron was significantly higher than those under iron depletion conditions (P<0.05). The relative expression levels of the four siderophore genes (iucB, iroB, irp1, entB) in K. pneumoniae strains isolated from liver abscesses cultured with additional iron were lower than those under iron depletion conditions (P<0.05). Conclusions: It is suggested by our research that iron in the environment can promote growth, biofilm formation and enhance virulence of K. pneumoniae causing liver abscesses. A lower expression of siderophore genes correlates with increased virulence of liver abscess-causing K. pneumoniae. Further deeper evaluation of these phenomena is warranted.

scholarly journals Effects of iron on the growth, biofilm formation and virulence of Klebsiella pneumoniae causing liver abscess

2019 ◽  
Author(s):  
Tao Chen ◽  
Guofeng Dong ◽  
Siqin Zhang ◽  
Xiucai Zhang ◽  
Yajie Zhao ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Liver Abscess ◽  
Biofilm Formation ◽  
Iron Chelator ◽  
Infection Model ◽  
Relative Expression Level ◽  
Liver Abscesses ◽  
Severe Infections ◽  
Lower Expression ◽  
Additional Iron

Abstract Background: Klebsiella pneumoniae is considered as the most clinically relevant species of Enterobacteriaceae, known to cause severe infections including liver abscesses. To the best of our knowledge,iron in human body primarily gathers in liver. Further understanding of effects of iron on K. pneumoniae causing liver abscess is a promising way to elucidate the mechanism of poor prognosis of liver abscess. Results: All tested K. pneumoniae including those collected from liver abscess and other sterile sites and K. pneumoniae ATCC 700603 cultured in LB broth containing 50 μM iron grew optimally and were in possession of the strongest biofilm formation ability, while worst growth and biofilm formation ability of the strains cultured in iron-deplete environment were observed. The infection model of G. mellonella larvae showed the virulence of K. pneumoniae cultured with additional iron was significantly higher than cultured with iron chelator (P<0.05). The relative expression level of the four siderophores genes (iucB, iroB, irp1, entB) in K. pneumoniae strains isolated from liver abscess cultured with additional iron was lower than that with iron chelator. Conclusions: It is suggested by our research that iron in the environment can promote the growth and enhance the biofilm formation ability of K. pneumoniae and the lower expression of siderophores genes may be one of the mechanisms of iron affecting the virulence of liver abscess-causing K. pneumoniae. Further deeper evaluation of these phenomenons is warranted.

scholarly journals Virulence Characteristics and Molecular Epidemiology of Pyogenic Liver Abscess Causing Multidrug Resistant Klebsiella pneumoniae in Wenzhou, China

2021 ◽  
Author(s):  
Zhongyong Wang ◽  
Siqin Zhang ◽  
Na Huang ◽  
Shixing Liu ◽  
Ye Xu ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Molecular Epidemiology ◽  
Liver Abscess ◽  
Biofilm Formation ◽  
Growth Curves ◽  
Pyogenic Liver Abscess ◽  
Multidrug Resistant ◽  
Infection Model ◽  
String Test ◽  
Serum Killing

Abstract Background To date, little is known about the virulence characteristics of pyogenic liver abscess (PLA) that cause multidrug resistant (MDR) Klebsiella pneumoniae (K. pneumoniae), which might be due to the rarity of these strains. This study aimed to analyze the virulence characteristics and molecular epidemiology of 12 MDR strains obtained from 163 PLA cases in a tertiary teaching hospital from the perspective of clinical characteristics, virulence phenotypes, and genotypes. Methods The MDR strains were obtained from sterile fluid samples collected from patients with PLA. The antimicrobial susceptibility testing was confirmed by the agar dilution method and microdilution broth method. The virulence phenotypes were analyzed by the growth curves, string test, capsular quantification, serum killing test, biofilm formation assay and infection model. Polymerase chain reaction (PCR) was used to investigate the virulence genotypes. The molecular epidemiology was identified by multilocus sequence typing (MLST). Results The results of growth curves, string test, capsular quantification, serum killing test, biofilm formation assay, and infection model revealed that the virulence phenotypes of the 12 PLA-causing MDR K. pneumoniae were similar to or more obvious than those of the typical hypervirulent K. pneumoniae strains. These MDR strains were mainly non-K1/K2 serotypes and carried multiple virulence genes. The results of MLST illustrated that the MDR strains were categorized into 9 sequence types. Conclusions This is the first study to analyze the virulence characteristics in PLA-causing MDR strains. The data revealed the coexistence of hypervirulence and MDR in PLA-causing MDR K. pneumoniae strains, and the clones of these strains were diverse and scattered. Also, one ST11 carbapenem-resistant hypervirulent strain was identified in PLA.

scholarly journals Importation of Entamoeba histolytica and predominance of Klebsiella pneumoniae in liver abscesses: a 7-year retrospective cohort study from the United Arab Emirates

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Hussam Mousa ◽  
Ghada Salameh Mohammed Al-Bluwi ◽  
Zainab Fathi Mohammed Al Drini ◽  
Huda Imam Gasmelseed ◽  
Jamal Aldeen Alkoteesh ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
United Arab Emirates ◽  
Liver Abscess ◽  
Hospital Admissions ◽  
Indian Subcontinent ◽  
Pyogenic Liver Abscess ◽  
Primary Diagnosis ◽  
Incidence Rates ◽  
Liver Abscesses ◽  
Potential Risk Factors

Abstract Background There is a dearth of information on liver abscesses in the United Arab Emirates. Herein, we describe the clinical features of liver abscesses and determine their incidence rates and clinical outcomes. Methods We retrospectively reviewed the clinical charts of adult patients with a primary diagnosis of liver abscess at a major hospital over a 7-year period. Results Amongst 45 patients, 82.2% (37/45) had a pyogenic liver abscess (PLA) and 17.8% (8/45) had amoebic liver abscesses (ALA). Overall, patients were young (median age 42 years, IQR 35–52), mostly males (77.8%, 35/45) from the Indian subcontinent (55.6%, 25/45), presented with fever (88.9%, 40/45) and abdominal pain (88.9%, 40/45), and had a solitary abscess on imaging (71.1% (32/45). Crude annual incidence rates were 35.9/100,000 hospital admissions (95% CI 26.2–48.0) and 5.9/100,000 inhabitants (95% CI 4.3–7.9). All ALA patients were from the Indian subcontinent (100%, 8/8). Klebsiella pneumoniae was the most frequent pathogen in PLA (43.2% [16/37], 95% CI 27.1–60.5%). The hospital stay was shorter in ALA (7.5 days, IQR 7–8.5) than in PLA (14 days, IQR 9–17). No deaths were recorded within 30 days of hospitalisation. Conclusions ALA was exclusively seen in migrants from the Indian subcontinent, suggesting importation. Further research to characterise K. pneumoniae isolates and assess potential risk factors is needed.

scholarly journals Genetic Requirements for Klebsiella pneumoniae-Induced Liver Abscess in an Oral Infection Model

2009 ◽  
Vol 77 (7) ◽  
pp. 2657-2671 ◽  
Author(s):  
Ya-Chun Tu ◽  
Min-Chi Lu ◽  
Ming-Ko Chiang ◽  
Shu-Ping Huang ◽  
Hwei-Ling Peng ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Liver Abscess ◽  
Regulatory Networks ◽  
Oral Infection ◽  
Genetic Regulatory Networks ◽  
Class I ◽  
Infection Model ◽  
Wild Type ◽  
Virulence Attenuation ◽  
Mutant Strains

ABSTRACT Klebsiella pneumoniae is the predominant pathogen of primary liver abscess. However, our knowledge regarding the molecular basis of how K. pneumoniae causes primary infection in the liver is limited. We established an oral infection model that recapitulated the characteristics of liver abscess and conducted a genetic screen to identify the K. pneumoniae genes required for the development of liver abscess in mice. Twenty-eight mutants with attenuated growth in liver or spleen samples out of 2,880 signature-tagged mutants that produced the wild-type capsule were identified, and genetic loci which were disrupted in these mutants were identified to encode products with roles in cellular metabolism, adhesion, transportation, gene regulation, and unknown functions. We further evaluated the virulence attenuation of these mutants in independent infection experiments and categorized them accordingly into three classes. In particular, the class I and II mutant strains exhibited significantly reduced virulence in mice, and most of these strains were not detected in extraintestinal tissues at 48 h after oral inoculation. Interestingly, the mutated loci of about one-third of the class I and II mutant strains encode proteins with regulatory functions, and the transcript abundances of many other genes identified in the same screen were markedly changed in these regulatory mutant strains, suggesting a requirement for genetic regulatory networks for translocation of K. pneumoniae across the intestinal barrier. Furthermore, our finding that preimmunization with certain class I mutant strains protected mice against challenge with the wild-type strain implied a potential application for these strains in prophylaxis against K. pneumoniae infections.

3-in-1: bilateral subcutaneous leg abscesses and liver abscess from Klebsiella pneumoniae

2020 ◽  
Vol 13 (9) ◽  
pp. e235926
Author(s):  
Mark Anthony Santiago Sandoval ◽  
Ma Carrissa Abigail Roxas ◽  
Maria Sonia Salamat ◽  
Jarold Pauig ◽  
Irewin Tabu ◽  
...  
Keyword(s):  
Risk Factors ◽  
Klebsiella Pneumoniae ◽  
Liver Abscess ◽  
Virulence Genes ◽  
Unusual Case ◽  
Ballet Dancer ◽  
Capsular Type ◽  
Leg Muscles ◽  
Liver Abscesses ◽  
Increased Blood Flow

Hypervirulent strains of Klebsiella pneumoniae are known to cause liver abscesses and other metastatic infections. Being Asian and having diabetes are known host risk factors. Here we present an unusual case of a Filipino ballet dancer–choreographer with diabetes presenting with bilateral leg pains initially thought to be cellulitis, but was eventually diagnosed as bilateral subcutaneous leg abscesses. He also had a liver abscess, thankfully asymptomatic, which was only discovered on imaging. The occurrence of three distant abscesses in one patient, hence ‘3-in-1,’ makes this case worth reporting. Bilateral subcutaneous leg abscesses as the presenting manifestation of this infection have not been reported yet. We hypothesise that his occupation which makes use of frequent contractions of leg muscles led to increased blood flow and preferentially directed blood-borne bacteria to localise in both legs. We have also characterised the pathogen with regards to its hypermucoviscous phenotype, capsular type, virulence genes and phylogeny.

scholarly journals Effects of iron on the growth, biofilm formation and virulence of Klebsiella pneumoniae causing liver abscess

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Tao Chen ◽  
Guofeng Dong ◽  
Siqin Zhang ◽  
Xiucai Zhang ◽  
Yajie Zhao ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Liver Abscess ◽  
Biofilm Formation

Clinical and Molecular Analysis of Klebsiella pneumoniae Causing Liver Abscess in China

2016 ◽  
Vol 26 (4) ◽  
pp. 245-251 ◽  
Author(s):  
Yunfang Sun ◽  
Hua Wu ◽  
Dingxia Shen
Keyword(s):  
Klebsiella Pneumoniae ◽  
Multiplex Pcr ◽  
Liver Abscess ◽  
Chinese Patients ◽  
Molecular Characteristics ◽  
Beijing Area ◽  
Liver Abscesses ◽  
String Test ◽  
Almost All ◽  
New Criteria

<b><i>Objective:</i></b> Hypervirulent <i>Klebsiella pneumoniae</i> (hvKP) has been characterized as the major pathogen associated with the development of liver abscesses. Although the prevalence of <i>K. pneumoniae</i> in liver abscesses in Chinese patients is on the rise, methods for the early laboratory identification and recognition of hvKP are lacking, and hvKP detection and surveillance are thus limited. <b><i>Methods:</i></b> A retrospective study was conducted in 240 patients with cultures that were positive for <i>K. pneumoniae</i>, who were hospitalized in the Hospital of Beijing area from May 2013 to August 2014. The clinical and molecular characteristics of <i>K. pneumoniae</i> strains that cause liver abscesses were studied. Thirty-eight (16.7%) of 240 patients positive for <i>K. pneumoniae</i> cultures had liver abscesses. <b><i>Results:</i></b> Among these <i>K. pneumoniae</i> isolates, 92.1% (35/38) and 84.2% (32/38) were <i>rmpA </i>and <i>aerobactin (abc)</i> positive, respectively, as indicated by multiplex PCR, while 81.6% (31/38) were string test positive. Intriguingly, <i>K. pneumoniae</i> isolates that were positive for <i>rmpA, abc</i>, or string test accounted for almost all isolates (97.3%; n = 37/38) and thus were defined as hvKP in this study. Based on the new criteria for hvKP, none of these hvKP strains were positive for extended spectrum β-lactamases. <b><i>Conclusions:</i></b> Compared to the string test alone, integrating rmpA and abc detection with the string test is robuster and more extensive in the identification of liver abscess-causing hvKP strains. Multiplex PCR assays may therefore accelerate the early laboratory detection of hvKP.

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