Microbial Biofilms
Chaminda Jayampath Seneviratne in Microbial Biofilms, 2017
Culture-dependent methodologies have identified P. aeruginosa as the most common pathogen in contact lens–related infections, followed by Serratia marcescens, S. aureus, Acanthamoeba, and Fusarium [90]. Bacterial composition based on 16S ribosomal RNA gene sequencing has revealed that Achromobacter, Stenotrophomonas, and Delftia as the predominant bacteria, showing their role in contact lens–related disease [90]. Moreover, bacterial biofilms may provide binding sites for protozoa such as Acanthamoeba, predisposing lens wearers at increased risk for Acanthamoeba infection if lenses had been previously contaminated with bacterial biofilm [94]. Fungal keratitis is commonly caused by filamentous fungi Fusarium and Aspergillus species and less commonly by yeast-like fungi Candida species [95]. Fusarium adhere to contact lenses and form penetration pegs, which are hyphae of the fungi that traverse into the matrix of lenses. Biofilm on contact lenses can also be mixed species in nature.
Gut microbiota: sculptors of the intestinal stem cell niche in health and inflammatory bowel disease
Published in Gut Microbes, 2021
Manasvini Markandey, Aditya Bajaj, Nicholas Edward Ilott, Saurabh Kedia, Simon Travis, Fiona Powrie, Vineet Ahuja
Advances in bio-imaging and molecular characterization of microbes have equipped us to explore microbial communities in distinct intestinal niches, such as mucosa-associated microbiota (MAM) and crypt-associated microbiota. Laser capture microdissection (LCM), coupled with 16s rRNA qPCR, enables crypt-autochthonous bacterial populations to be studied. Rowan et al. report the presence of commensal bacteria within the crypt-associated mucus gel in health and colitis, with bacterial counts being significantly reduced in patients with acute ulcerative colitis.22 A ‘crypt-specific core microbiota’ (CSCM), seated deep at the base of cecal and colonic crypts, was established by Pedron et al. This population is distinct from the MAM and consists of aerobic bacteria like Acinetobacter, Delftia, and Stenotrophomonas sp. in mice. Human colonic crypts are colonized predominantly by Firmicutes, with small proportions of the bacteria characterized in murine crypts.3,4
Bacteriophages as tools for biofilm biocontrol in different fields
Published in Biofouling, 2021
Camila Mendes Figueiredo, Marilia Silva Malvezzi Karwowski, Romeu Cassiano Pucci da Silva Ramos, Nicoly Subtil de Oliveira, Lorena Caroline Peña, Everdan Carneiro, Renata Ernlund Freitas de Macedo, Edvaldo Antonio Ribeiro Rosa
In water and sewage treatment, the use of phages has also shown potential. Inclusion of bacteriophages on reactor membranes leads to microbial reduction on the membrane surface, thereby increasing the efficiency of processing (Goldman et al. 2009). In effluent treatment using phages to control biofilms formed by three different species of bacteria (P. aeruginosa, Acinetobacter johnsonii, and Bacillus subtilis), attachment reduction of 40%–60%, with continuous inactivation of planktonic cells and freshly formed biofilm, was achieved (Bhattacharjee et al. 2015). Biofouling from a multidrug-resistant bacterium, Delftia tsuruhatensis ARB-1, was also eliminated from a lab-scale membrane bioreactor using a lytic bacteriophage (Narendrakumar et al. 2019; Abriat et al. 2020).
Adhesion of Pseudomonas aeruginosa, Achromobacter xylosoxidans, Delftia acidovorans, Stenotrophomonas maltophilia to contact lenses under the influence of an artificial tear solution
Published in Biofouling, 2020
Jaya Dantam, Lakshman N. Subbaraman, Lyndon Jones
S. maltophilia is a multi-drug resistant organism and has been identified as an emerging pathogen (Brooke 2012; Adegoke et al. 2017) that generally exhibits low virulence. Previously, S. maltophilia was considered an opportunistic pathogen in debilitated hosts. However, more recently it has also been identified as a true pathogen in immunocompetent individuals. Although commonly associated with nosocomial infections (Brooke 2012), the ocular manifestations of S. maltophilia include keratitis (Holifield and Lazzaro 2011), conjunctivitis (Penland and Wilhelmus 1996), scleritis (Chen et al. 2005), dacryocystitis (Penland and Wilhelmus 1996), and endophthalmitis (Chen et al. 2010). Recently Wu et al. (2016) reported that, after pre-existing corneal disease/previous corneal surgery, CL wear has been cited as the second most common predisposing factor for S. maltophilia keratitis. Further, in subjects with microbial keratitis (Wiley et al. 2012), S. maltophilia has been detected in storage cases as well as attached to CLs. Watanabe et al. (2014) showed that several strains of S. maltophilia recovered from storage cases, CLs, and ocular swabs were resistant to certain multi-purpose disinfectant solutions, despite their susceptibility to different antibiotics. Presumably, S. maltophilia may serve as a scaffolding bacterium in CL storage cases (Watanabe et al. 2014), as it has also been associated with polymicrobial contamination (Bottone et al. 1992; Gray et al. 1995; Wu et al. 2016). Although rare, D. acidovorans commonly found in soil (Olm et al. 2017) can also affect both immunocompromised as well as immunocompetent patients (Bilgin et al. 2015). Cases of infectious keratitis by D. acidovorans have been reported in patients with immunocompromised cornea and those wearing CLs (Lema et al. 2001; Lee et al. 2008; Ray and Lim 2013). Further, more than 40% of the CL storage cases of CL wearers with microbial keratitis harbored Delftia spp. (Wiley et al. 2012).
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