Bacteroides fragilis endocarditis: a case report and review of literature

Rodrigues, Cristhieni; Siciliano, Rinaldo Focaccia; Zeigler, Rogério; Strabelli, Tânia Mara Varejão

doi:10.1590/s1413-86702012000100020

Cited by 5 publications

(5 citation statements)

References 17 publications

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“…2 However, if B. fragilis moves out of its niche in the gut, it can cause serious, and potentially fatal, infections in humans; it is the most frequently isolated anaerobic bacterium from patients with deep tissue infections, intra-abdominal infections, bacteraemia, abscesses and endocarditis. 1,3,4 Metronidazole is the most commonly used drug worldwide to treat infections involving B. fragilis 5,6 and has been the treatment of choice for surgical prophylaxis (e.g. for colorectal surgery) for almost 40 years.…”

Section: Introductionmentioning

confidence: 99%

Deficiency of the ferrous iron transporter FeoAB is linked with metronidazole resistance in Bacteroides fragilis

Veeranagouda¹,

Husain²,

Boente³

et al. 2014

Journal of Antimicrobial Chemotherapy

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Section: Introductionmentioning

confidence: 99%

Deficiency of the ferrous iron transporter FeoAB is linked with metronidazole resistance in Bacteroides fragilis

Veeranagouda¹,

Husain²,

Boente³

et al. 2014

Journal of Antimicrobial Chemotherapy

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“…Bacteroides spp. are the predominant anaerobes in the human gut, where they maintain a generally beneficial relationship with the host. − However, these bacteria can escape the gastrointestinal tract and cause disease. ,− Bacteroides fragilis is the leading cause of anaerobic sepsis and bacteremia in humans − , and possesses virulence factors that allow survival outside the host digestive tract and determine pathogenicity . Among the primary B. fragilis virulence determinants is a metalloprotease toxin known as fragilysin, or BFT, which is expressed by enterotoxigenic strains. − BFT contributes to sepsis and pro-inflammatory disease within the colon by cleaving cadherin family proteins and thereby compromising tissue barrier integrity. − BFT is synthesized as an inactive zymogen that consists of an N-terminal prodomain, a flexible linker, and a C-terminal catalytic domain .…”

mentioning

confidence: 99%

Activation Mechanism of the Bacteroides fragilis Cysteine Peptidase, Fragipain

et al. 2016

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Enterotoxigenic Bacteroides fragilis produces a secreted metalloprotease known as B. fragilis toxin (BFT), which contributes to anaerobic sepsis, colitis, and colonic malignancy in mouse models of disease. A C11 family cysteine protease, fragipain (Fpn), directly activates BFT in the B. fragilis cell by removing the BFT prodomain. Fpn is itself a proenzyme and is autoactivated upon cleavage at an arginine residue in its activation loop. We have defined the proteolytic active site of Fpn, demonstrated that Fpn autoactivation can occur by an in trans loop cleavage mechanism, and characterized structural features of the Fpn activation loop that control peptidase activity against several substrates, including BFT. An arginine residue at the autocleavage site determines the fast activation kinetics of Fpn relative to the homologous C11 protease, PmC11, which is cleaved at lysine. Arginine to alanine substitution at the cleavage site ablated peptidase activity, as did partial truncation of the Fpn activation loop. However, complete truncation of the activation loop yielded an uncleaved, pro form of Fpn that was active as a peptidase against both Fpn and BFT substrates. Thus, Fpn can be transformed into an active peptidase in the absence of activation loop cleavage. This study provides insight into the mechanism of fragipain activation and, more generally, defines the role of the C11 activation loop in the control of peptidase activity and substrate specificity.

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“…oxygen. The ability to survive exposure to oxygen is a different type of factor that facilitates the survival and thus pathogenicity of the organism [27,39,43,65,69].…”

Section: The Genus Bacteroidesmentioning

confidence: 99%

The Role of the Bacteroides spp. in Bacteraemia

Wysocki

Kierzkowska

Podsiadły

2022

Postępy Mikrobiologii - Advancements of Microbiology

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Anaerobic bacteraemia is not frequent (1.2–13.7%), but is associated with a high mortality rate of 16–27%. Anaerobic infections including bacteraemia nearly always arise from contamination by endogenous bacteria into contiguous or other sites like gastrointestinal tracts, genito-urinary tracts, abscesses etc. Factors leading to anaerobic bacteraemia are mainly surgical procedures, crush injuries, the presence of foreign bodies, tissue necrosis, tumours, diabetes. The most common infectious anaerobic agents are Gram-negative bacilli belonging to the Bacteroides/Parabacteroides, which under normal conditions constitute the natural human microflora. An important factor in the virulency of B. fragilis is the ability to form abscesses; a limited infection may progress to bacteraemia and then systemic inflammatory response syndrome and sepsis. Anaerobic bacteraemia mainly affects adults, with elderly patients over 65 years with underlying diseases. The importance of anaerobic bacteria in neonatal bacteraemia and sepsis is a relatively new phenomenon. In contrast the prevalence of anaerobes in bloodstream infections in children is extremely rare with children between 2 and 6 years of age having the least risk ranging 0–0.5% overall. The incidence of recovery of anaerobes in neonatal bacteraemia varies between 1.8% and 12.5%. The majority of cases reported in the literature were due to Bacteroides spp. (41%) other cultured anaerobes belonged to Clostridium spp. (32%), Peptostreptococcus spp. (20%). Blood cultures remain the gold standard for detection of the etiologic both anaerobes and aerobes agent of bloodstream infection. In recent years significant progress has been made in the methods used in the diagnosis of anaerobes, which significantly reduced the time and cost of the examination. Currently, the mass spectometry MALDI-TOF MS and 16S rRNA sequencing are increasingly used for anaerobic bacteria identification. In 2022, EUCAST published standardized disk diffusion method for the drug susceptibility testing of Bacteroides spp. and other 4 clinically significant anaerobes. Determining the sensitivity of anaerobes to antibiotics is important due to the increasing drug resistance in this group. Number of B. fragilis strains resistant to clindamycin and moxifloxacin is increasing. According to the published studies sensitivity to clindamycin and moxifloxacin is significantly rare and occurs in 64% and 68% of isolates and in 50.8% and 58.2% respectively. Carbapenems and metronidazole continue to be the most effective active antibiotics to be used in the empirical therapy of anaerobic bacteraemia. There are case reports of infections caused by multidrug-resistant strains of Bacteroides spp, meaning resistant to at least three antibiotics from different groups. Rapid microbial diagnosis, targeted therapy and surgical treatment of a possible source of infection are crucial in treatment of sepsis caused by anaerobic bacteria.

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Bacteroides fragilis endocarditis: a case report and review of literature

Cited by 5 publications

References 17 publications

Deficiency of the ferrous iron transporter FeoAB is linked with metronidazole resistance in Bacteroides fragilis

Deficiency of the ferrous iron transporter FeoAB is linked with metronidazole resistance in Bacteroides fragilis

Activation Mechanism of the Bacteroides fragilis Cysteine Peptidase, Fragipain

The Role of the Bacteroides spp. in Bacteraemia

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