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Endocarditis
Published in Firza Alexander Gronthoud, Practical Clinical Microbiology and Infectious Diseases, 2020
The medical team is treating a 54-year-old woman for a Streptococcus gallolyticus bacteraemia. She remains febrile and unstable despite treatment with benzylpenicillin according to the hospital guidelines. They phone you to ask whether or not they should broaden the antibiotic therapy. You notice that she had three blood cultures with the same microorganism. The MIC for penicillin is 0.25, which makes the Streptococcus intermediate sensitive to penicillin. You change the antibiotic to ceftriaxone because you suspect infective endocarditis. Additionally, you advise an urgent echocardiogram.The penicillin MIC dictates the duration and the dose of benzylpenicillin or switch to alternative agent in endocarditis caused by streptococci.
Infections of the Blood
Published in Keith Struthers, Clinical Microbiology, 2017
The presence of bacteria in the blood requires identification of the likely source. There is the obvious association of Escherichia coli in blood and an ascending urinary tract infection (UTI). When native valve endocarditis is identified it can be straightforward to determine the likely source of the organism. The patient with endocarditis caused by a streptococcus of the mouth flora, such as Streptococcus sanguinis, can have poor dentition, and this needs to be addressed as part of the patient's management, usually involving the maxilla-facial surgical team. More unusual situations occur, and one is the identification of Streptococcus gallolyticus in blood culture. This organism is a minor member of the normal flora of the colon. However, it is recognized that there is an association that can develop between it and a large bowel malignancy, likely due to a specific interaction between the organism and these malignant cells. The streptococcus gains a selective growth advantage, from where it accesses the blood. Once in the blood it has the potential to initiate infective endocarditis. The finding of Streptococcus gallolyticus in blood culture, often in the setting of endocarditis, is an alert to investigate this malignancy; if found this is removed before any valve surgery.
Increasing clinical impact and microbiological difficulties in diagnosing coagulase-negative staphylococci in infective endocarditis – a review starting from a series of cases
Published in Current Medical Research and Opinion, 2022
Nicoleta-Monica Popa-Fotea, Alexandru Scafa-Udriste, Grigore Iulia, Alina Ioana Scarlatescu, Nicoleta Oprescu, Cosmin Mihai, Miruna Mihaela Micheu
Although the pathogenic microorganism spectrum has not changed much over time, with staphylococci, streptococci and enterococci representing more than 80% of all cases (with the mention that Staphylococcus (S.) aureus exceeds streptococci by about 12%5) there has been an increasing trend in streptococci-mediated IE after guideline changes in IE prophylaxis in countries like England6 or the Netherlands7. Oral streptococci are the leading cause of IE in the general population, while S. aureus and coagulase-negative staphylococci (CoNS) are more common in intravenous drug abusers, patients with valvular prostheses or in healthcare-associated cases. Furthermore, the prevalence of group D streptococci (Streptococcus gallolyticus) is increased among the elderly8. The environment in which the infection takes place – community versus health-care facilities – favours certain aetiologies, with S. aureus being responsible for approximately 50% of healthcare related IE (followed by CoNS, mostly related with intravascular devices or recent valvular prosthesis). Although a significant increase in CoNS EI has been reported in recent years, mainly due to the boost of invasive manoeuvres and the intensification of prosthetic valves implantation, on the other hand, the incidence of native valve CoNS endocarditis has also risen9,10.
“Driver-passenger” bacteria and their metabolites in the pathogenesis of colorectal cancer
Published in Gut Microbes, 2021
Marion Avril, R. William DePaolo
The Streptococcus gallolyticus (Sgg) species has been postulated to be both a “driver” and a “passenger”.53 As a driver bacteria, Sgg is found to be predominant in pre-malignant tissue and induces specific inflammatory cytokines (IL-1, COX-2, and IL-8) increasing cell proliferation via the upregulation of the β-catenin pathway and its oncogenic downstream targets (c-Myc and cyclin D). In the passenger model, the presence of Sgg in hyperplastic tissue activates the Wnt pathway downregulating Slc10A2, a bile acids transporter leading to activation of a specific “bacteriocin” which enables Sgg to eliminate commensals like Enterococci. Together, these effects of Sgg accelerate transformation from pre-malignant to malignant epithelium.53 Another recent study published by Aymeric and colleagues found that in mice genetically prone to CRC colonization by Sgg to be 1,000-fold higher in tumor-bearing mice. The Sgg were found to be secreting a specific “bacteriocin” (called “gallocin”) that can kill closely related gut commensals.54 Thus, they concluded that Sgg is a cancer-promoting bacterium (a “driver”) only if pre-malignant conditions (in this case genetic susceptibility) exist for Sgg to become a driver bacterium, Sgg first needs to colonize the colon as a passenger bacterium.
Novel association of Streptococcus gallolyticus subspecies pasteurianus and hepatocelluar carcinoma: opening new frontiers
Published in Scandinavian Journal of Gastroenterology, 2018
Pratibha Kale, Vikas Khillan, Shiv Kumar Sarin
The clinical characteristics of the patients with Streptococcus gallolyticus infection and the difference in the two study groups are shown in Table 1. A total of 54 (79.41%) patients had chronic liver disease. Portal hypertension was present in 55(80.9%) patients. Cirrhosis as an etiology of portal hypertension was evident in 38 (55.9%) patients, and cholestasis was seen only in a single patient. The alcoholic liver disease was present in 21 (30.9%) patients. The non-alcoholic fatty liver disease was present in 5 (7.35%) patients. Liver disease associated with viral etiology was evident in 10 patients (14.7%), namely HBV (4), HCV (5) and HEV (1). Acute kidney injury was evident in 22 (32.35%) cases and 16 (23.5%) patients had diabetes.