Streptococcus bovis bacteremia related to colon adenoma in a chronic hemodialysis patient

A Narrative Literature Review on Sepsis: A Primary Manifestation of Colorectal Neoplasm

Sepsis and colorectal cancer (CRC) exhibit a complex relationship that warrants further exploration. This review delves into the interplay of factors between sepsis and CRC, uncovering shared pathophysiological traits and potential bacterial associations. Understanding these connections could pave the way for earlier diagnosis, improved management, and enhanced outcomes in CRC patients. The role of immune system dysfunction, hypoalbuminemia, and specific microbial imbalances, such as Streptococcus bovis and Clostridium septicum, are discussed. Recognizing sepsis in CRC patients is crucial for timely intervention, and tailored approaches encompassing antibiotic therapy, source control measures, and cancer treatment are essential for comprehensive care. Monitoring biomarkers and ratios can provide valuable insights into complications and overall health outcomes. A multidisciplinary approach involving various specialists is necessary to address the global burden of CRC and its association with sepsis while exploring novel interventions, such as fecal microbiota transplantation and personalized care. We conducted a thorough search using reputable databases such as PubMed, Scopus, and Google Scholar to investigate the connection between sepsis and CRC. We refined our search terms, utilized sidebar filters, and examined references in selected articles. This meticulous process helped us create a comprehensive literature review and gain valuable insights into this relationship.

The Association of Streptococcus gallolyticus Subspecies pasteurianus Bacteremia with the Detection of Premalignant and Malignant Colonic Lesions

Streptococcus gallolyticus subspecies (subsp.) gallolyticus (formerly bovis biotype I) bacteremia has been associated with colonic adenocarcinoma. The bovis species underwent reclassification in 2003. Subtypes of gallolyticus are associated with colonic malignancy but are less frequent, resulting in less awareness. A 71-year-old male admitted with worsening lower back pain and fevers. Initial vital signs and laboratory data were within normal limits. MRI revealed lumbosacral osteomyelitis and antibiotics were initiated. Blood cultures showed Streptococcus species, prompting a transesophageal echocardiogram (TEE) revealing vegetations on the mitral and aortic valves. The etiology for his endocarditis was unclear. A colonoscopy was suggested, but his clinical instability made such a procedure intolerable. Final cultures revealed Streptococcus gallolyticus subsp. pasteurianus (previously bovis biotype II). After antibiotic completion he underwent aortic grafting with valve replacements. Later, he was readmitted for Streptococcus bacteremia. After a negative TEE, colonoscopy revealed a 2.5 × 3 cm cecal tubulovillous adenoma with high-grade dysplasia suspicious for his origin of infection. Clinicians understand the link between Streptococcus gallolyticus subsp. gallolyticus (bovis type I) and malignancy, but the new speciation may be unfamiliar. There are no guidelines for managing S. gallolyticus subsp. pasteurianus bacteremia; therefore a colonoscopy should be considered when no source is identified.

Gut microbiota, inflammation and colorectal cancer

Although genes contribute to colorectal cancer, the gut microbiota are an important player. Accumulating evidence suggests that chronic infection and the ensuing inflammation contributes to tumor initiation and tumor progression. A variety of bacterial species and tumor-promoting virulence mechanisms have been investigated. Significant advances have been made in understanding the composition and functional capabilities of the gut microbiota and its roles in cancer. In the current review, we discuss the novel roles of microbiota in the progression of colon cancer. Although microbiota technically include organisms other than bacteria e.g., viruses and fungi, this review will primarily focus on bacteria. We summarize epidemiological studies of human microbiome and colon cancer. We discuss the progress in the scientific understanding of the interplay between the gut microbiota, barrier function, and host responses in experimental models. Further, we discuss the potential application in prevention, diagnosis, and therapy of colon cancer by targeting microbiota. We discuss the challenges lie ahead and the future direction in studying gut microbiome in colon cancer to close the gap between the basic sciences and clinical application.

Molecular characterization of a novel mosaic tet(S/M) gene encoding tetracycline resistance in foodborne strains of Streptococcus bovis

The presence of antibiotic-resistance (AR) genes in foodborne bacteria of enteric origin represents a relevant threat to human health in the case of opportunistic pathogens, which can reach the human gut through the food chain. Streptococcus bovis is a human opportunistic pathogen often associated with infections in immune-compromised or cancer patients, and it can also be detected in the environment, including fermented foods. We have focused on the molecular characterization of a tetracycline (Tet)-resistance gene present in 39 foodborne isolates of S. bovis phenotypically resistant to this drug. The gene was identified as a novel tet(S/M) fusion, encoding a mosaic protein composed of the N-terminal 33 amino acids of Tet(S), in-frame with the Tet(M) coding sequence. Heterologous expression of the mosaic gene was found to confer Tet resistance upon Escherichia coli recipients. Moreover, the tet(S/M) gene was found to be transcriptionally inducible by Tet under the endogenous tet(S) promoter in both S. bovis and E. coli. Nucleotide sequencing of the surrounding genomic region of 16.2 kb revealed large blocks of homology with the genomes of Streptococcus infantarius and Lactococcus lactis. A subregion of about 4 kb containing mosaic tet(S/M) was flanked by two copies of the IS1216 mobile element. PCR amplification with primers directed outwards from the tet(S/M) gene identified the presence of a 4.3 kb circular form corresponding to the intervening chromosomal region between the two IS1216 elements, but lacking a replication origin. The circular element shared extensive overall homology with a region of the multidrug-resistance plasmid pK214 from Lc. lactis, containing tet(S), as well as the IS1216 transposase-containing element and intervening non-coding sequences. Linear reconstruction of the insertion events likely to have occurred within this genomic region, inferred from sequence homology, provides further evidence of the chromosomal rearrangements that drive genomic evolution in complex bacterial communities such as the gut and food microbiota.

The association of Streptococcus bovis/gallolyticus with colorectal tumors: the nature and the underlying mechanisms of its etiological role

Streptococcus bovis (S. bovis) bacteria are associated with colorectal cancer and adenoma. S. bovis is currently named S. gallolyticus. 25 to 80% of patients with S. bovis/gallolyticus bacteremia have concomitant colorectal tumors. Colonic neoplasia may arise years after the presentation of bacteremia or infectious endocarditis of S. bovis/gallolyticus. The presence of S. bovis/gallolyticus bacteremia and/or endocarditis is also related to the presence of villous or tubular-villous adenomas in the large intestine. In addition, serological relationship of S. gallolyticus with colorectal tumors and direct colonization of S. gallolyticus in tissues of colorectal tumors were found. However, this association is still under controversy and has long been underestimated. Moreover, the etiological versus non-etiological nature of this associationis not settled yet. Therefore, by covering the most of up to date studies, this review attempts to clarify the nature and the core of S. bovis/gallolyicus association with colorectal tumors and analyze the possible underlying mechanisms.

Catheter-related bacteremia caused by Comamonas testosteroni in a hemodialysis patient

Comamonas testosteroni has rarely been implicated as a human pathogen. In general, the outcome of C. testosteroni infections is favorable. We report a case of fatal bacteremia caused by C. testosteroni in a 64-year-old woman on hemodialysis.