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Bacteriology of Ophthalmic Infections
Published in K. Balamurugan, U. Prithika, Pocket Guide to Bacterial Infections, 2019
Arumugam Priya, Shunmugiah Karutha Pandian
Coryneform bacteria comprises a group of aerobic, asperogenous, gram-positive, rod-shaped bacteria, which includes the following genera: Corynebacterium, Turicella, Arthrobacter, Brevibacterium, Dermabacter, Propionibacterium, Rothia, Exiguobacterium, Oerskovia, Cellulomonas, Sanguibacter, Microbacterium, Aureobacterium, Arcanobacterium, and Actinomyces (Funke et al., 1997). Though less frequently encountered, Corynebacterium and Propionibacterium are the most-common coryneform bacteria associated with several systemic and ocular infections. The species C. macginleyi, isolated from an eye specimen, was the first lipophilic coryneform bacteria reported (Riegel et al., 1995). C. macginleyi resides as an ocular flora but acts as an opportunistic pathogen in conjunctivitis and other ocular infections. It also has been described as a conjunctiva-specific pathogen because it is predominantly isolated from conjunctivitis eyes and infrequently found in sight-threatening infections such as keratitis and endophthalmitis (Joussen et al., 2000; Ly et al., 2006; Suzuki et al., 2007). Ruoff et al. (2010) reported corneal ulceration and scaring caused by C. macginleyi as a sole causative agent, suggesting that C. macginleyi can cause ocular infection even when it is not associated with other opportunistic or pathogenic organisms. Detection and identification of C. macginleyi species is problematic as it is fastidious, requires enriched media, and being sequestered by other organisms. Culture-independent techniques like PCR will enumerate the presence of C. macginleyi. In a case report, Ferrer et al. (2004) encountered sterile endophthalmitis followed by cataract surgery. However, the sequence analysis showed C. macginleyi as the causative agent of endophthalmitis. Mycobacterium keratitis is often misdiagnosed with Corynebacterium keratitis (Garg et al., 1998). C. pseudodipthericum was found in conjunctivitis in extremely rare instances (Joussen et al., 2000).
Infective endocarditis by Actinomyces species: a systematic review
Published in Journal of Chemotherapy, 2023
Petros Ioannou, Stella Baliou, Ioanna Papakitsou, Diamantis P. Kofteridis
Actinomyces species are Gram-positive bacteria that colonize the mouth, colon, and vagina and are the causes of actinomycosis, which is a slowly progressive infection that may mimic malignancy due to the invasiveness of tissues and the ability to form sinus tracts [1]. The most common encountered species associated with actinomycosis is A. israeilii [2]. Other species that may also cause actinomycosis, even though they are less frequently encountered are Actinomyces naeslundii, Actinomyces viscosus, Actinomyces odontolyticus, Actinomyces gerencseriae, Actinomyces graevenitzii, and Actinomyces meyeri [3–9]. With development of newer methods for pathogen identification, such as MALDI-TOF and genotypic methods such as comparative 16S ribosomal RNA (rRNA), new Actinomyces species have been identified from both human and animal specimens [6,10,11]. On the other hand, some Actinomyces species have been reclassified as Trueperella, Actinotignum, or Cellulomonas due to the same pathogen identification methods [6,10–14].
Linear and branched β-Glucans degrading enzymes from versatile Bacteroides uniformis JCM 13288T and their roles in cooperation with gut bacteria
Published in Gut Microbes, 2020
Ravindra Pal Singh, Sivasubramanian Rajarammohan, Raksha Thakur, Mohsin Hassan
The β- glucans have gained strong attention as an imperative in food supplements, wherein they can act as either immunostimulants in cancer treatments and inflammation10,11 or microbiome modulatory agents.12 The β- glucans are predominantly present in the daily human diet in soluble and insoluble fiber states. These are structurally diverse with a variety of glycosidic linkages. For instance, β-glucans extracted from Euglena (known as paramylon) and bacterial polysaccharides (known as curdlan) are linear in chain with β-1-3 linked,13 while marine macroalgal-extracted glucan (known as laminarin) is branched with β-1-3 and β-1-6 linkages.14 Furthermore, frequency and length of β-1-6 linked glucans depend on the type of sources, i.e. yeast, Laminarin digitata, Lasallia pustulata, and Lentinus edodes.15–18 Curdlan is one of the abundant bio-resources that can be synthesized by several bacteria, including Agrobacterium,19Rhizobium,20 and Cellulomonas species.21,22 In addition, huge quantities of laminarin can accumulate in marine environment upon degradation of macroalgae, and plays a major role in marine carbon cycle.23,24 Therefore, extraction of curdlan and laminarin is much simpler as compared to other natural glycans and can be easily exploited for nutraceutical perspectives.25–27 However, laminarin and curdlan utilizing capability of gut bacteria is still poorly understood.
Prenatal androgen exposure causes hypertension and gut microbiota dysbiosis
Published in Gut Microbes, 2018
Shermel B. Sherman, Nadeen Sarsour, Marziyeh Salehi, Allen Schroering, Blair Mell, Bina Joe, Jennifer W. Hill
Bifidobacteriales was the only order that was significantly reduced within the PNA animals (Fig. 8a, Supplementary Table 2). At the family level, bacteria from Yaniellaceae, Geodermatophilaceae, Microbacteriaceae, Nakamurellaceae, Corynebacteriaceae, Promicromonosporaceae, and Nocardiaceae were significantly enriched within the PNA animal fecal microbiota. Bacteria from Brevibacteriaceae and Dermabacteraceae were significantly decreased within the PNA fecal microbiota. At the genus level, bacteria from Yaniella, Rathayibacter, Modestobacter, Microbispora, Arthrobacter, Frigoribacterium, Cellulomonas, Aeromicrobium, Xylanimicrobium, and Rhodococcus were significantly enriched within the PNA animal fecal microbiota. Bacteria from Bifidobacterium, Corynebacterium, Brevibacterium, Brachybacterium, Adlercreutzia, and Rothia were significantly decreased within the PNA fecal microbiota.