Growth and survival of a chlorine resistive gram-negative rod bacterium, Protomonas extorquens isolated dominantly from drinking tank-water.

Abstract

We detected some heterotrophic bacteria from drinking tank-water by using standard agar medium cultured for 7 days at 25C. Bacteria produced pink water-insoluble pigment were isolated most frequently. These isolates were polar monotrichous gram-negative rod and vacuolated. They produced weakly urease, oxidase and catalase. They utilized D-arabinose, galactose, methanol, ethanol and glycerol as carbon sources. They contained a large amount of unsaturated straight-chain fatty acid C 18:1. The G+C ratio of DNA base composition ranged from 65.8 to 66.3. The isolates were identified as Protomonas extorquens. Good growth of these bacteria were observed at 30C, and between pH5.0 and 9.0 by incubation of sterilized drinking water in tank. Growth was not observed in the presence of 1.5% sodium chloride. The generation-times of P. extorquens were determined by duplicate experiments about 5.4h. They have been survived for a long period (250 days) in tankwater. The resistance of P. extorquens to free residual chlorine was very high. The exposure time to kill completely 105 cfuml-1 in 1.0mg•1-1 of free residual chlorine was 10 minutes. P. extorquens is worthy of notice as unknown pathogens for men and source of nosocomial infection.

Reclassification of Methylobacterium chloromethanicum and Methylobacterium dichloromethanicum as later subjective synonyms of Methylobacterium extorquens and of Methylobacterium lusitanum as a later subjective synonym of Methylobacterium rhodesianum

“…These bacteria also inhabit humanmade environments, such as potable water supplies, bathrooms, and washstands, where they sometimes produce pink ropy masses of growth. Because many Methylobacterium strains are resistant to chlorination and disinfection with ultraviolet beam (Furuhata et al, 1989(Furuhata et al, , 1993Hiraishi et al, 1995), they survive after sterilization and contaminate the food manufacturing environment. Furthermore, Methylobacterium strains are slow growers and can survive and replicate on poor carbon sources (Hiraishi et al, 1995).…”

Use of Polymerase Chain Reaction-amplified 16S rRNA Gene Sequences to Identify Pink-pigmented Bacteria Found in a Potable Water Treatment System.

“…The two strains were previously classified as "Protomonas" sp. on the basis of the following observations: they were strictly aerobic, gramnegative rods, had motility by means of polar flagella, contained catalase and oxidase, utilized methanol as the sole carbon source, produced bacteriochlorophyll a under aerobic growth conditions, and possessed ubiquinone- 10 designated MS 141 F) and positions 543 to 562 (5'-GATTCCGAGCA-ACGCTAGCC-3'; designated a 543R) was also used. Forward primer MS 141 F included a sequence complementary to oligodeoxynucleotide probe 9-a reported as being specific to the 16S rRN A of serine pathway methylotrophs34), which belong to the alpha subclass of the Proteobacteria.…”

Methylobacterium spp. as Emerging Opportunistic Premise Plumbing Pathogens

“…Methylobacterium spp. share a number of characteristics in common with OPPPs, including: chlorine resistance [20][21][22], biofilm formation [23,24], and desiccation tolerance [23,25]. Methylobacterium spp.…”