Characterization and identification of pink-pigmented facultative methylotrophic bacteria from human scalf and nasal cavity

• Main Authors: Uy, Jamela Ann T., Uy, Miko Mariel O.
• Format: text
• Language: English
• Published: Animo Repository 2009
• Subjects: Methylobacterium; Bacteria; Bacteriology
• Online Access: https://animorepository.dlsu.edu.ph/etd_bachelors/5285
• Institution: De La Salle University

Pink-pigmented facultative methylotrophic bacteria (PPFM) have been reported to cause infections in both immunocompetent and immunocompromised individuals. This requires investigation on whether they are part of the normal human microbiota. A total of 17 PPFM bacterial isolates from the nasal cavity and scalp of healthy individuals were obtained from the Microbiology Laboratory of the Nursing Science Research Department, St. Luke's College of Nursing. Nine PPFM bacterial isolates came from the nasal cavity while eight came from the human scalp of healthy volunteers. The bacterial isolates produced light pink to reddish-pink pigments and medium sized, butyrous, raised opaque colonies. They were Gram-negative and rod-shaped, and were positive for urease, catalase and oxidase production. The PPFM isolates were identified using 16s rDNA sequencing. Three isolates from the scalp were identified to be Methylobacterium rhodesianum, three were found to be Methylobacterium lusitanum, and two were Methylobacterium sp. On the other hand, four PPFMs from the nasal cavity were identified to be Methylobacterium populi, one was Methylobacterium aminovorans and four bacterial isolates were found to be Methylobacterium sp. In addition, all the 17 isolates were found to carry the mxaF gene coding for the alpha subunit of the methanol dehydrogenase. Polymerase chain reaction yielded the expected 550 bp amplicons. Amplicons from five representative PPFM bacterial isolates (three from the scalp and two from the nasal cavity) were sequenced and were identified as the mxaF structural gene of methanol dehydrogenase.