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Phytomedicines Targeting Antibiotic Resistance through Quorum Sensing and Biofilm Formation Associated with Acne Vulgaris
Published in Namrita Lall, Medicinal Plants for Cosmetics, Health and Diseases, 2022
Isa A. Lambrechts, Namrita Lall
RNAIII plays a role in the transcription of several virulent factors associated with the bacteria. RNAIII contains the hld gene that codes for the phenol-soluble modulin, a delta toxin. These delta toxins play a role in the detachment of bacteria from the biofilm. This detachment could spread the bacteria, establish biofilms and release virulence factors such as hemolysins, protease and lipase enzymes associated with quorum sensing and various diseases. In addition, the RNAIII gene has been found to prevent the translation of the repressor of toxin protein (Rot) that results in the upregulation of enzymes such as lipase and protease involved in acne vulgaris (Le and Otto, 2015; Vuong et al., 2003; Kong, Vuong, and Otto, 2006).
Role of Bacteria in Dermatological Infections
Published in K. Balamurugan, U. Prithika, Pocket Guide to Bacterial Infections, 2019
Thirukannamangai Krishnan Swetha, Shunmugiah Karutha Pandian
S. epidermidis is a ubiquitous gram-positive skin and mucosal membrane colonizer, which exerts a mutualistic relationship with host. It forms the major part of microbial barrier that precludes the colonization of other pathogens. In a competitive environment, it secretes lantibiotics (i.e., lanthionine-containing antibacterial peptides) often referred as bacteriocins, which prevent the colonization of S. aureus and GAS (Sahl, 1994; Cogen et al., 2007). Also, accessory gene regulator (agr) locus found in commensal S. epidermidis produces peptide pheromones that activate the agr QS system of competing bacteria, which in turn, reduces colonization and down-regulates the expression of virulence factors by increasing the production of pheromones such as phenol soluble modulin (Otto, 2001). In addition, S. epidermidis boosts the host immune defense by eliciting the signaling of toll like receptor (TLR). The pattern recognition receptors TLRs, in turn, specifically recognize different pathogen-associated molecular patterns and activate the host immune system accordingly.
Symbiotic microorganisms: prospects for treating atopic dermatitis
Published in Expert Opinion on Biological Therapy, 2022
Rongrong Chai, Zongguang Tai, Yunjie Zhu, Chaochao Chai, Zhongjian Chen, Quangang Zhu
The skin flora can also be used as a topical probiotic, and it can better adapt to the new skin microenvironment [141]. Skin flora transplantation holds promise for the treatment of AD [142]. Staphylococcus caprae inhibited S. aureus colonization in a mouse model [143]. S. epidermidis has also been shown to produce antimicrobial substances that inhibit S. aureus and Streptococcus pyogenes [97]. When a probiotic solution containing several strains of Cutibacterium acnes prepared from the donor microbiota was applied to healthy adults, it temporarily regulated the C. acnes population without adverse reactions [144]. When culturable gram-negative bacteria from healthy individuals were transplanted into a vitamin D analog (MC903)-induced mouse model, they inhibited the growth of S. aureus, enhanced barrier function, activated innate immunity, reduced water loss, and alleviated AD symptoms [145]. ShA9 is a Staphylococcus strain isolated from healthy human skin. In a first-in-human phase 1 double-blinded randomized trial of 54 adults with S. aureus-positive AD [146], ShA9 inhibited the mRNA expression of phenol-soluble modulin alpha and reduced the severity of AD. Yoshihiro et al. [147] showed that Staphylococcus cohnii strains isolated from either mouse or human skin microbiota prevented and ameliorated dermatitis in Tmem79 mice, thus having great potential as effective live biotherapeutics for skin inflammation and AD.
Alternative approaches to treat bacterial infections: targeting quorum-sensing
Published in Expert Review of Anti-infective Therapy, 2020
Pipat Piewngam, Janice Chiou, Priyanka Chatterjee, Michael Otto
Targets of the Agr system are regulated predominantly via RNAIII, a small regulatory RNA that exerts many of its effects via blocking translation of Rot (repressor of toxins) [22,23]. As a result, translation of enterotoxins, alpha-toxin, leukocidins, degradative exoenzymes, and further targets is upregulated, whereas some surface proteins such as protein A are down-regulated [6]. In addition to the P2 and P3 promoters, AgrA can bind to the promoter regions of phenol-soluble modulin (PSM) psmα and psmβ operons [24], exerting exceptionally strict and direct control of these virulence determinants. The PSMs are amphipathic, surfactant-like peptides with multiple functions, including lytic activity on leukocytes, erythrocytes, and other cell types, biofilm structuring and dispersal, and further activities believed to be important during the commensal state of staphylococci [25]. The PSM family also includes δ-toxin, which is encoded within RNAIII [22].
Novel strategies for rapid identification and susceptibility testing of MRSA
Published in Expert Review of Anti-infective Therapy, 2020
Masako Mizusawa, Karen C Carroll
The utility of a variety of MRSA specific spectra including assessment of specific peaks, clusters of peaks, and entire spectra has been evaluated [101]. Van Belkum et al. categorize the methods into four main types [102]. The first of these is whole-cell mass spectrometry (WCMS). To be successful, the resistance proteins must fall within the mass range used for WCMS. For example, the PBP2a protein that confers methicillin resistance cannot be detected by MALD-TOF MS because the molecular weight is only 76 kDa [101]. MRSA strains belonging to S. aureus SCCmec types II, III, and VIII contain a phenol-soluble modulin that gives an intense peak at m/z of 2,415 Da [103,104]. In a retrospective study of 283 S. aureus isolates recovered from positive blood cultures, Rhoads et al. manually examined the Vitek MS instrument Acquisition Station software version 1.4.2b (bioMerieux; Durham, NC) for the 2415 m/z peak [105]. In addition, a set of well-characterized S. aureus strains representing USA100-USA1200 pulsotypes were also tested [105]. The latter were tested on both the Vitek MS and the Bruker Biotyper system using the FlexAnalysis software version 3.4 (Bruker Daltonics, Billerica, MA). The Verigene BCID-GP system was used as the reference method and identified 137 of the S. aureus as MRSA of which 39% contained the 2415 m/z peak; specificity was 100% [105]. In this study, only USA100, USA200, and USA600 pulsotypes had the high-intensity m/z 2415 peak detected by both systems [105]. Similarly, Josten et al. noted a sensitivity of 95% and specificity of 100% for detection of PSM-mec in agr positive S. aureus reference and clinical strains [104]. As concluded by others, if the 2415 m/z peak is present, it can be used to predict resistance, however, its absence does not equate to susceptibility [102,104,105].