Pseudomonas cremoris sp. nov., a novel proteolytic species isolated from cream

Abstract

During a study investigating the microbiota of raw milk and its semi-finished products, strains WS 5106T and WS 5096 were isolated from cream and skimmed milk concentrate. They could be assigned to the genus Pseudomonas by their 16S rRNA sequences, but not to any validly named species. In this work, a polyphasic approach was used to characterize the novel strains and to investigate their taxonomic status. Examinations based on the topology of core genome phylogenomy as well as average nucleotide identity (ANIm) comparisons suggested a novel Pseudomonas species within the Pseudomonas fluorescens subgroup. With pairwise ANIm values of 90.1 and 89.8 %, WS 5106T was most closely related to Pseudomonas nabeulensis CECT 9765T and Pseudomonas kairouanensis CECT 9766T. The G+C content of strain WS 5106T was 60.1 mol%. Morphologic analyses revealed Gram-stain-negative, aerobic, catalase and oxidase positive, rod-shaped and motile cells. Proteolysis on skimmed milk agar as well as lipolysis on tributyrin agar occurred at both 28 and 6 °C. Tolerated growth conditions were temperatures between 4 and 34 °C, pH values between 6.0 and 8.0, and salt concentrations of up to 5 %. Fatty acid profiles showed a pattern typical for Pseudomonas , with C16 : 0 as the dominant component. The major cellular polar lipids were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol and the dominating quinone was Q-9. Based on these results, it is proposed to classify the strains as a novel species, Pseudomonas cremoris sp. nov., with WS 5106T (=DSM 111143T=LMG 31863T) as type strain and WS 5096 (=DSM 111129=LMG 31864) as an additional strain.

Bactericidal Effect of Pseudomonas oryziphila sp. nov., a Novel Pseudomonas Species Against Xanthomonas oryzae Reduces Disease Severity of Bacterial Leaf Streak of Rice

“…cremoris sp. nov. was reported in the previous study ( Hofmann et al, 2021 ). For example, ANIm comparisons indicated that the type strain WS 5106 was a novel species within the P .…”

“…A similar case about the taxonomic characterization of P. cremoris sp. nov. was reported in the previous study (Hofmann et al, 2021). For example, ANIm comparisons indicated that the type strain WS 5106 was a novel species within the P. fluorescens subgroup, but the pairwise ANIm values of 90.1 and 89.8% showed that WS 5106 was most closely related to Pseudomonas nabeulensis CECT 9765 T and Pseudomonas kairouanensis CECT 9766 T (Hofmann et al, 2021).…”

“…Pseudomonas is a diverse genus with more than 200 different species, whereas many new isolates are being classified as a novel species. In 2019, for instance, 16 novel Pseudomonas species were described from different sources such as tree bark, sewage, or raw milk ( Hofmann et al, 2021 ). Our results support that strain 1257 is a novel Pseudomonas species, which is more closely related to P. entomophila than P. mosselii .…”

“…For example, ANIm comparisons indicated that the type strain WS 5106 was a novel species within the P . fluorescens subgroup, but the pairwise ANIm values of 90.1 and 89.8% showed that WS 5106 was most closely related to Pseudomona s nabeulensis CECT 9765 T and Pseudomona s kairouanensis CECT 9766 T ( Hofmann et al, 2021 ). Therefore, some phenotypic analyses such as physiological and biochemical characteristics, or antagonistic activity, are necessary for further classification status.…”

Pseudomonas rustica sp. nov., isolated from bulk tank raw milk at a German dairy farm

“…Due to the permanent cooling of the milk during the whole processing line, the microbiota of raw milk shifts mainly to psychrophilic organisms, especially Pseudomonas species [6]. In milk and dairy products, several novel Pseudomonas species have been identified, mainly from the Pseudomonas fluorescens lineage ( fluorescens and fragi subgroup) [7–11]. Several studies have shown that the psychrophilic genus Pseudomonas is one of the most prevalent and abundant genera in raw milk [6, 12].…”