Biochemical and chemical characterization of pink-pigmented oxidative bacteria

Abstract

The biochemical and chemical characteristics were determined for 156 clinical isolates of pink-pigmented bacteria that are similar to but distinct from Methylobacterium extorquens (synonymous with Pseudomonas mesophilica). These isolates were gram-negative, nonfermentative, usually nonvacuolated, coccoid rods; all grew at 35 degrees C and were catalase and urease positive; the majority grew on MacConkey agar and were variable for oxidase production and motility. On the basis of oxidation of xylose and mannitol and hydrolysis of esculin, these 156 strains were subdivided into four groups that were designated "pink coccoid" groups I, II, III, and IV. Groups I, II, and III are similar to an unnamed taxon described by Gilardi and Faur in 1984; only strains of group IV hydrolyze esculin. The cellular fatty acid compositions of strains of groups I, II, and III were essentially identical and differed from strains of group IV by the absence of 3-OH-C14:0 and the presence of C19:0 delta and 2-OH-C19:0 delta. The fatty acid composition of group IV strains was most similar to that of M. extorquens but differed by the presence of small amounts of two C17:1 acids, 3-OH-C16:0, and 2-OH-C18:1.

Applications of cellular fatty acid analysis.

“…Many belonging to these groups are unusual opportunistic pathogens that may grow slowly and need to be distinguished from traditional fastidious pathogens. In characterizing a collection of strains that resembled Methylobacterium extorquens, Wallace et al (159) relied heavily on CFA composition to define groups with similarities and groups with differences. CFA analysis may reveal differences not readily apparent by phenotypic characterization.…”

Environmentally induced lipidome adaptation in the bacterial model organismM. extorquens

“…Finally, to 104 characterize lipidomic adaptation at varying cell densities, cells were harvested at early, mid and late 105 exponential, as well as stationary growth stages (Figure 1b). Cellular lipid content was analyzed by 106 high resolution shotgun mass spectrometry (Ejsing et al, 2009) It has been previously shown that M. extorquens produces lipids with 16 and 18 carbon atoms-long 111 acyl chains, and with up to 2 double bonds per acyl chain (Bradley et al, 2017;Wallace et al, 1990). 112…”

Systemic Infection of an Immunocompromised Patient with Methylobacterium zatmanii

“…The strain was able to oxidize methanol (growth on oxidative-fermentative basal medium [Merck, Darmstadt, Germany]) supplemented with 1% methanol under aerobic conditions), was oxidative, and gave positive catalase, oxidase, and urease reactions (API 20 NE, bioMeriéux, Nürtingen, Germany). Oxidation of methanol is characteristic of members of the genus Methylobacterium and allowed differentiation from bacteria belonging to the closely related genus Roseomonas (7,(12)(13)(14). Further criteria to distinguish the strain isolated in this study from the genus Roseomonas were Gram-stain morphology and failure to grow on MacConkey agar (12)(13)(14).…”

“…Oxidation of methanol is characteristic of members of the genus Methylobacterium and allowed differentiation from bacteria belonging to the closely related genus Roseomonas (7,(12)(13)(14). Further criteria to distinguish the strain isolated in this study from the genus Roseomonas were Gram-stain morphology and failure to grow on MacConkey agar (12)(13)(14). The biochemical characteristics of diagnostic importance of the isolated strain are summarized in Table 2.…”

“…The bacteria were isolated from various patient specimens, such as blood, cerebrospinal fluid, sputum, bronchoscopic material, and synovial membrane. Since few cases of infection with Methylobacterium species have been described, this may reflect the difficulties in cultivation and identification of the bacteria (13). In general, methylobacteria are opportunistic pathogens of low virulence.…”