![\"\"](\"https:\/\/microregistrar.com\/wp-content\/uploads\/2023\/07\/image-14.png\")
<\/figure>\n<\/div>\n\n\n\nImage: Henry Vandyke Carter and one more author \u2013 Henry Gray (1918) Anatomy of the Human Body<\/em> (See \u201cBook\u201d section below) Bartleby.com: Gray\u2019s Anatomy, Plate 1205 (Wikipedia)<\/a><\/p>\n<\/div>\n<\/div>\n\n\n\n Corynebactrium spp.<\/strong> Most cases of CM have been associated with eye infections \u2013 CM has also been reported from various non-ocular infections. For example \u2013 Co-infection-<\/strong><\/p>\n\n\n\n In many ophthalmic cases (approx 50%), other pathogenic bacteria and viruses have also been isolated from the clinical specimens. The most common associated bacteria was Staph aureus.<\/p>\n\n\n\n Risk factors \u2013<\/strong><\/p>\n\n\n\n Eye \u2013 Contact lens, a breach in epithelial surface, Gram stain \u2013 typical of Corynebacterium spp. (see above)<\/p>\n\n\n\n Colonies \u2013 On blood agar, CM produces very small (<1mm diameter) nonhaemolytic colonies after 48 hrs (large reddish-beige colonies can be seen when blood agar is supplemented with Tween-80).<\/p>\n\n\n\n Tests \u2013 catalase positive, oxidase negative, nitrate is reduced to nitrite, urease negative. [Riegel 1995]<\/p>\n\n\n\n Final identification can be made using \u2013 MALDI-ToF (reliable identification), API coryne, 16S rRNA sequencing supplemented with rpo<\/em> B gene sequencing.<\/p>\n\n\n\n Many isolates are likely classed as contaminants and not followed up\/reported.<\/p>\n\n\n\n The reported susceptibility varies \u2013<\/p>\n\n\n\n Sagerfors et al. reported CM susceptible to benzylpenicillin, vancomycin, gentamicin, ciprofloxacin and moxifloxacin. Chloramphenicol susceptibility was variable based on MIC. Sagerfors, S., Poehlein, A., Afshar, M. et al. Clinical and genomic features of Corynebacterium macginleyi-associated infectious keratitis. Sci Rep 11, 6015 (2021). https:\/\/doi.org\/10.1038\/s41598-021-85336-w<\/a><\/p>\n\n\n\n Fong et al, Corynebacterium macginleyi in the era of MALDI-TOF MS: epidemiology, susceptibility patterns and prevalence of co-infection, Pathology<\/a> (article in press)<\/p>\n\n\n\n Riegel et al, Genomic Diversity and Phylogenetic Relationships among Lipid-Requiring Diphtheroids from Humans and Characterisation of Corynebacterium macginkyi sp. nov, INTERNATIONAL JOURNAL OF SYSTEMATIC BACTERIOLOGY, Jan. 1995, p. 128-133 0020-7713\/95\/$04.00 + 0<\/a><\/p>\n\n\n\n Eguchi et al, High-Level Fluoroquinolone Resistance in Ophthalmic Clinical Isolates Belonging to the Species Corynebacterium macginleyi, Journal of Clinical Microbiology, Vol. 46, No. 2<\/a><\/p>\n\n\n\n\n
Corynebacterium is an aerobic gram-positive, non-motile rod, often with clubbed ends but could be pleomorphic. In gram stain, it may stain unevenly and appear beaded. They group in a characteristic way, which has been described as the form of a \u201cV\u201d, \u201cpalisades\u201d, or \u201cChinese letters\u201d. Metachromatic granules are usually present representing stored phosphate regions.
Corynebacterium are facultative anaerobe or aerobe and may grow slowly. On blood agar, they produce small greyish colonies.
Selective and differential media for Corynebacterium is Hoyle\u2019s tellurite medium.
Three species of Corynebacterium, C. diphtheriae, C. ulcerans, and C. pseudotuberculosis, carry the phage borne diphtheria tox gene, which is required to produce toxin. These three species are capable of causing diphtheria or diphtheria like illness.
Other diphtheria species are usually the commensals of the skin and mucous membrane but can be opportunistic pathogens.<\/p>\n<\/blockquote>\n\n\n\nDiseases associated with C macginleyi<\/h4>\n\n\n\n
conjunctivitis,<\/strong>
keratitis,<\/strong>
corneal ulcer,<\/strong>
preorbital cellulitis,<\/strong>
blebitis and<\/strong>
endophthalmitis<\/strong>
[Sagerfors, Nature 2021][Fong, Pathology 2021].<\/p>\n\n\n\n
catheter-related urinary tract infection,<\/strong>
catheter-related blood-stream infection,<\/strong>
endocarditis,<\/strong>
pneumonia in an HIV-infected<\/strong> individual or ventilated patient,<\/strong>
tracheostomy site infection in a patient with laryngeal carcinoma and<\/strong>
post orthopaedics surgery surgical site infection.<\/strong><\/p>\n\n\n\n![\"\"\/](\"https:\/\/synapse.koreamed.org\/upload\/synapseData\/ArticleImage\/0086ic\/ic-42-319-g002-l.jpg\")
Extraocular \u2013 prosthetic material, immunocompromised state (HIV, malignancy)<\/p>\n\n\n\nLaboratory identification<\/h4>\n\n\n\n
![\"Corynebacterium](\"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/0\/06\/Corynebacterium_diphtheriae_Gram_stain.jpg\")
Treatment<\/h4>\n\n\n\n
Fong et al. reported all the isolates were susceptible to vancomycin, ciprofloxacin and linezolid. Susceptibility to clindamycin, penicillin and tetracycline was variable.
Eguchi et al. reported high-level fluoroquinolone resistance from Japan, which could be specific to the country or population group.
Funke et al. reported that C. macginleyi is uniformly susceptible to penicillins, quinolones, and aminoglycosides.<\/p>\n\n\n\nReference<\/h2>\n\n\n\n