Role of Bacteria in Dermatological Infections
K. Balamurugan, U. Prithika in Pocket Guide to Bacterial Infections, 2019
Corynebacterium spp. are diphtheroid, gram-positive, and facultative anaerobic mycobacterium, which constitute approximately 50% of skin microflora (Blaise et al., 2008). The skin microflora majorly constitute two species of Corynebacterium namely, C. diphtheriae and nondiphtheriae corynebacteria (diphtheroids). C. diphtheriae are reported to be witnessed in cutaneous ulcers of drug abusers, alcoholics, and individuals exposed to poor hygienic environment. The nondiphtheriae cornynebacteria or diphtheroids include totally 17 species, which are diversely distributed in humans and other animals (Cogen et al., 2008). The diphtheroid majorly found in human epithelium is C. jeikeium. It acts as microbial barrier and protects the host from pathogenic attack by the production of bacteroids. The enzyme superoxide dismutase produced by C. jeikeium for shielding against the attack of free radicals, confers protection to host against free radicals (Storz and Imlay, 1999).
Bacitracin and Gramicidin
M. Lindsay Grayson, Sara E. Cosgrove, Suzanne M. Crowe, M. Lindsay Grayson, William Hope, James S. McCarthy, John Mills, Johan W. Mouton, David L. Paterson in Kucers’ The Use of Antibiotics, 2017
Bacitracin is highly active against most Gram-positive bacteria, particularly Staphylococcus aureus and Streptococcus pyogenes. Group C and G beta-hemolytic streptococci are generally less susceptible, and group B streptococci are usually resistant (Baker et al., 1976; Finland et al., 1976). Susceptibility of Enterococcus species is variable, and high minimum inhibitory concentrations (MICs) are frequently found (Mondy et al., 2001; Tran et al., 2015). Corynebacterium diphtheriae is susceptible. Clostridium difficile is commonly susceptible and the majority of strains are synergistically inhibited by the combination of bacitracin and rifampicin (Bacon et al., 1991). However, recent surveys show very high MICs in the majority of clinical isolates in some regions of the world (Citron et al., 2003; Mackin et al., 2015). Susceptibility of anaerobic bacteria is also variable (see Citron et al., 2003).
Factors Controlling the Microflora of the Skin
Michael J. Hill, Philip D. Marsh in Human Microbial Ecology, 2020
Until relatively recently there was a belief that only one genus of coryneform (Corynebacterium) was present on human skin; this belief hampered attempts to devise taxonomic schemes for the coryneforms. We now know that representatives of the genera Brevibacterium, Corynebacterium, and Propionibacterium are the major coryneforms with contributions from other genera which are at present hard to assess. Coryneforms are separated principally on the composition of their cell walls. Brevibacterium species possess meso-diaminopimelic acid (DAP) and galactose as the major sugar but lack characteristic lipids known as mycolic acids. Corynebacterium species also possess meso-DAP but in addition have an arabinogalactan and relatively small mycolic acids (Rhodococcus C24–36 is distinguished from Corynebacterium C24–30 chiefly by its slightly longer mycolic acids) while Propionibacterium species possess LL-DAP and glucose, lack mycolic acids, and are best grown under anaerobic conditions, despite being facultative aerobes.
Management and prevention of drug resistant infections in burn patients
Published in Expert Review of Anti-infective Therapy, 2019
Roohi Vinaik, Dalia Barayan, Shahriar Shahrokhi, Marc G Jeschke
Similarly, fusidic acid is another potential candidate with efficacy primarily against gram-positive organisms – specifically, Staphylococcus spp., Streptococcus spp., and Corynebacterium spp. While interest in the drug declined due to discovery of more potent antibiotics, fusidic acid has become an attractive alternative due to the advent of antimicrobial resistance. Ulkür et al. demonstrate that 2% fusidic acid treatment in contaminated rat full-thickness burns is capable of eradicating MRSA [100]. Furthermore, numerous creams containing a combination of fusidic acid and antifungal agents have been developed, allowing for rapid and easy application in burn patients [99]. Usnic acid is another topical formulation that possesses antimicrobial activity against gram-positive biofilm-forming bacteria. Similar to fusidic acid, usnic acid is efficacious against MRSA and is capable of inhibiting multiple S. aureus strains at lower concentrations than other antibiotics (e.g. oxacillin, clindamycin) in vitro [101]. In addition to its antimicrobial activity, collagen-based films containing usnic acid demonstrated a diminished inflammatory reaction at 7 days post-burn and improvement in collagenization density by 14 days in a rat burn model [102].
The emerging role of skin microbiome in atopic dermatitis and its clinical implication
Published in Journal of Dermatological Treatment, 2019
Jean-François Stalder, Joachim W. Fluhr, Tim Foster, Martin Glatz, Ehrhardt Proksch
Corticosteroids are essential in resolving the inflammatory component of AD; given the close inter-relation between inflammation and S. aureus abundance, a number of studies have also sought to establish how corticosteroid treatment influences the skin flora. In a study that compared the colonization of S. aureus in a group of children with severe AD using desonide with a group using a placebo, desonide treatment led to significant improvements in clinical symptoms (p < .001), and reduced pruritus (p < .01), and sleep loss (p < .05). S. aureus density also decreased significantly (p < .001) (46). In addition to reduced colonization of S. aureus, corticosteroid treatment also increased the abundance of typical commensals associated with healthy skin, such as Streptococcus spp., Propionibacterium spp., and Corynebacterium spp (46).
The pharmacology of antibiotic therapy in hidradenitis suppurativa
Published in Expert Review of Clinical Pharmacology, 2020
Claudio Marasca, Paolo Tranchini, Vincenzo Marino, Maria Carmela Annunziata, Maddalena Napolitano, Davide Fattore, Gabriella Fabbrocini
It is well known that a predominant part of patients with HS are smokers and S. aureus has also been linked to this habit [96]. Jemec et al. proposed that S. aureus may be involved only in the initial process of disease, facilitating anatomical alterations in the hair follicles by inflammation and necrosis [94]. Regarding other microbes detected in HS, Sartorius et al. found Coagulase-negative staphylococci (CNS) in the deep layers of 10 patients undergoing carbon dioxide laser. Nine of the patients carried Corynebacterium spp. and two alpha-hemolytic streptococci at various levels. Among the anaerobic microorganisms, Gram-positive cocci were the most common bacteria. Contrary to what they expected, S. aureus was not found in any cultures from acute inflammatory nodules of HS exacerbations [97]. A case–control study recently showed in patients with HS and healthy controls the following five microbiome types: Corynebacterium species (type I), Acinetobacter and Moraxella species (type II), Staphylococcus epidermidis (type III), Porphyromonas and Peptoniphilus species (type IV), and P. acnes (type V). In lesional skin, microbiome types consisted predominantly of type I or type IV. Microbiome type IV was not detected in healthy controls [98]. Other authors investigated the morphology of the axillary skin microbiota, showing fewer bacteria and less biofilm in patients with HS compared with healthy controls [99].
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