Pigment producing pathogenic bacteria ~ University Notes

Pigment producing pathogenic bacteria:

Pseudomonas species

Pseudomonas aeruginosa growing on Mueller Hinton Agar — *Pseudomonas aeruginosa* (green color) growing on Mueller Hinton Agar

Pseudomonas aeruginosa is a leading bacterial pathogen in hospital settings and for immunocompromised patients (those with underlying conditions such as neutropenia, burns or cystic fibrosis). P. aeruginosa ( aeruginosa, which derives from a Latin word denoting the color of copper rust) produces a green fluorescent pigment (fluorescein/pyoverdin) and a blue pigment (pyocyanin). These pigments impart greenish hue to the sputum of cystic fibrosis patients with chronic lung infection, gives colonies and infected wound dressings a greenish-blue coloration.

P. aeruginosa is usually recognized by the pigments it produces and the distinctive smell of cultures. . When the culture is left at room temperature, pigment colour becomes more intense. A minority of strains are non-pigment producing.
Other species of Pseudomonas (such as P.fluorescens and P. putida) also produce pigments.

Serratia

Serratia marcescens (mneomonic: Mars is red) is notable for its production of a bright red pigment called “prodigiosin”. Some strains produce a red pigment in nutrient agar at room temperature

Staphylococcus aureus

Staphylococcus aureus (aureus = “golden”, Latin) produces multiple carotenoid pigments, one being golden yellow pigment (Staphyloxanthin). When cultured on sheep blood agar, S. aureus can be differentiated from other beta-hemolytic cocci by elaboration of golden pigment. Pigment is less pronounced in young colonies.

Violacein from Chromobacterium violaceum

Characteristics pigment production by Chromobacterium violaceum — Characteristics pigment production byChromobacterium violaceum

Chromobacterium violaceum, an agent of localized skin infection or localized lymphadenitis which occasionally causes fatal septicemia elaborates a blue-violet pigment, violacein.

Group B Streptococcus

Group B Streptococcus (GBS), the leading etiologic cause of severe neonatal bacterial infection, expresses an orange-red pigment, called granadaene. This Orange pigment is produced by Streptococcus agalactiae when cultured on serum starch agar anaerobically.

Iron porphyrin of Porphyromonas gingivalis

Porphyromonas gingivalis is a gram negative anaerobic bacilli, which is implicated in the pathogenesis of certain forms of periodontal disease. Arginine- and lysine-specific gingipain proteases of P. gingivalis degrade hemoglobin to release iron (III) protoporphyrin IX , which is dimerized to form the micro-oxo bis-haem-containing black pigment of the organism.

Nontuberculous Mycobacteria

The genus Mycobacterium includes many bacteria that produce pigments. . The Runyon classification systemgroups mycobacteria based on growth rate and pigment production in the presence of light or dark. M. tuberculosis is a nonchromogen, i.e. it does not produce pigment in light or darkness

Fungal pathogens which produce pigments

Aspergillus fumigatus is a filamentous fungus that elaborates a melanin-like substance during its conidial stage of growth.

Cryptococcus neoformans is an encapsulated yeast-like fungus that produces a brown or black melanin pigment by conversion of diphenols or homogentisic acid this coloration can be used for rapid identification of colonies on cornmeal agar, a medium commonly used in yeast isolation

Penicillum marneffei is an opportunistic pathogen causing systemic penicilliosis in AIDS patients. It produces characteristic red pigment in Sabouraud dextrose agar.