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Analysis of the Bacterial Diversity in Liver Abscess: Differences Between Pyogenic and Amebic Abscesses.

ABSTRACT: Several recent studies have demonstrated that virulence in Entamoeba histolytica is triggered in the presence of both pathogenic and nonpathogenic bacteria species using in vitro and in vivo experimental animal models. In this study, we examined samples aspirated from abscess material obtained from patients who were clinically diagnosed with amebic liver abscess (ALA) or pyogenic liver abscess (PLA). To determine the diversity of bacterial species in the abscesses, we performed partial 16S rRNA gene sequencing. In addition, the E. histolytica and Entamoeba dispar species were genotyped using tRNA-linked short tandem repeats as specific molecular markers. The association between clinical data and bacterial and parasite genotypes were examined through a correspondence analysis. The results showed the presence of numerous bacterial groups. These taxonomic groups constitute common members of the gut microbiota, although all of the detected bacterial species have a close phylogenetic relationship with bacterial pathogens. Furthermore, some patients clinically diagnosed with PLA and ALA were coinfected with E. dispar or E. histolytica, which suggests that the virulence of these parasites increased in the presence of bacteria. However, no specific bacterial groups were associated with this effect. Together, our results suggest a nonspecific mechanism of virulence modulation by bacteria in Entamoeba.

SUBMITTER: Reyna-Fabian ME

PROVIDER: S-EPMC4710420 | biostudies-literature | 2016 Jan

REPOSITORIES: biostudies-literature

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Analysis of the Bacterial Diversity in Liver Abscess: Differences Between Pyogenic and Amebic Abscesses.

Reyna-Fabián Miriam E ME Zermeño Valeria V Ximénez Cecilia C Flores Janin J Romero Miguel F MF Diaz Daniel D Argueta Jesús J Moran Patricia P Valadez Alicia A Cerritos René R

The American journal of tropical medicine and hygiene 20151116 1

Several recent studies have demonstrated that virulence in Entamoeba histolytica is triggered in the presence of both pathogenic and nonpathogenic bacteria species using in vitro and in vivo experimental animal models. In this study, we examined samples aspirated from abscess material obtained from patients who were clinically diagnosed with amebic liver abscess (ALA) or pyogenic liver abscess (PLA). To determine the diversity of bacterial species in the abscesses, we performed partial 16S rRNA ...[more]

PMID: 26572872

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Project description:BACKGROUND: Commensurate with the advances in diagnostic and therapeutic radiology in the past two decades, percutaneous needle aspiration and catheter drainage have replaced open operation as the first choice of treatment for both single and multiple pyogenic liver abscesses. There has been little written on the place of surgical resection in the treatment of pyogenic liver abscess due to underlying hepatobiliary pathology or after failure of non-operative management. METHODS: The medical records of patients who underwent resection for pyogenic liver abscess over a 15-year period were retrospectively reviewed. The demographics, time from onset of symptoms to medical treatment and operation, site of abscess, organisms cultured, aetiology, reason for operation, type of resection and outcome were analysed. There were 49 patients in whom the abscesses were either single (19), single but multiloculated (11) or multiple (19). The median time from onset of symptoms to medical treatment was 21 days and from treatment to operation was 12 days. The indications for operation were underlying hepatobiliary pathology in 20% and failed non-operative treatment in 76%. Two patients presented with peritonitis from a ruptured abscess. RESULTS: The resections performed were anatomic (44) and non-anatomic (5). No patient suffered a recurrent abscess or required surgical or radiological intervention for any abdominal collection. Antibiotics were ceased within 5 days of operation in all but one patient. The median postoperative stay was 10 days. There were two deaths (4%), both following rupture of the abscess. DISCUSSION: Except for an initial presentation with intraperitoneal rupture and, possibly, cases of hepatobiliary pathology causing multiple abscesses above an obstructed duct system that cannot be negotiated non-operatively, primary surgical treatment of pyogenic liver abscess is not indicated. Non-operative management with antibiotics and percutaneous aspiration/drainage will be successful in most patients. If non-operative treatment fails, different physical characteristics of the abscesses are likely to be present and partial hepatectomy of the involved portion of liver is good treatment when performed by an experienced surgeon.

Project description:While Klebsiella pneumoniae is a common cause of nosocomial and community-acquired infections, including pneumonia and pyogenic liver abscess, little is known about the population structure of this bacterium. In this study, we investigated the prevalence and molecular characteristics of K. pneumoniae isolates from carriers, pyogenic liver abscess patients, and pneumonia patients, and genomic and phenotypic assays were used to determine the differences among the isolates. A total of 232 K. pneumoniae isolates were subtyped into 74 sequence types (STs). The isolates from different sources had their own STs, and the predominant subtypes in liver abscess and pneumonia patients were ST23 and ST11, respectively. Pangenome analysis also distinguished three phylogroups that were consistent with the isolate sources. The isolates collected from liver abscess patients carried significantly more virulence factors, and those from pneumonia patients harbored significantly more resistance genes and replicons. Almost all isolate STs (93/97 [95.88%]) from liver abscesses strongly correlated with the virulence factor salmochelin, while most pneumonia isolate STs (52/53 [98.11%]) from pneumonia did not correlate with salmochelin. The isolates collected from liver abscesses showed higher virulence in the cytotoxicity and mouse models. These data provide genomic support for the proposal that isolates collected from carriers, liver abscess patients, and pneumonia patients have distinct genomic features. Isolates from the different sources are largely nonoverlapping, suggesting that different patients may be infected via different sources. Further studies on the pathogenic mechanisms of salmochelin and other virulence factors will be required. IMPORTANCE While Klebsiella pneumoniae is a common cause of nosocomial and community-acquired infections, including pneumonia and pyogenic liver abscess, little is known about the population structure of this bacterium. We collected 232 isolates from carriers, pyogenic liver abscess patients, and pneumonia patients, and the isolates from different sources had their own sequence types. Pangenome analysis also distinguished three phylogroups that were consistent with the isolate sources. The isolates collected from liver abscess patients carried significantly more virulence factors, and those from pneumonia patients harbored significantly more resistance genes and replicons. Besides, there was a strong link between salmochelin and liver abscess. The isolates collected from liver abscesses also showed higher virulence in the cytotoxicity and mouse models. Isolates collected from different sources have distinct genomic features, suggesting that different patients may be infected via different sources.

Dataset Information

Analysis of the Bacterial Diversity in Liver Abscess: Differences Between Pyogenic and Amebic Abscesses.

Publications

Analysis of the Bacterial Diversity in Liver Abscess: Differences Between Pyogenic and Amebic Abscesses.

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