Luteimonas lumbrici sp. nov., a novel bacterium isolated from wormcast

Management Practices Affecting Lesser Mealworm Larvae (Alphitobius diaperinus) Associated Microbial Community in a Broiler House and After Relocating With the Litter Into Pastureland

Lesser mealworms are often found infesting production houses used to raise broiler chickens. Previous studies have investigated pathogenic microorganisms associated with the larvae, but a more thorough study relating total microbiome changes due to management procedures and flock rotations was needed. Additionally, there is a question of what microbiota are transferred into the environment when the litter, in which larvae reside, is piled in pastureland for use as fertilizer and where interactions with the soil and other fauna can occur. This study chronicled, by the 16S rRNA sequencing, the bacterial community profile of larvae in a broiler grow-out house synchronizing to when birds were added to and removed from the house over 2.5 years. The profile was found to be relatively constant despite 11 flock rotations and management disruptions, specifically litter cleanout procedures and the addition of new birds or bedding. In contrast, once removed from the controlled broiler house environment and placed into open pastureland, the substantial microbial diversity brought with the larvae showed greater fluctuation in structure with environmental conditions, one of which was rainfall. Surprisingly, these larvae survived at least 19 weeks, so the potential for moving larval-associated microbes into the environment needs further assessment to minimize the risk of relocating foodborne pathogens and also to assess those bacteria-generating metabolites that have benefits to plant growth when using the litter as a fertilizer. The characterization of their microbiome is the first step to investigating the influences of their microbes on the manmade and environmental ecosystems.

Adult Alphitobius diaperinus Microbial Community during Broiler Production and in Spent Litter after Stockpiling

The facilities used to raise broiler chickens are often infested with litter beetles (lesser mealworm, Alphitobius diaperinus). These beetles have been studied for their carriage of pathogenic microbes; however, a more comprehensive microbiome study on these arthropods is lacking. This study investigated their microbial community in a longitudinal study throughout 2.5 years of poultry production and after the spent litter, containing the mealworms, was piled in pastureland for use as fertilizer. The mean most abundant phyla harbored by the beetles in house were the Proteobacteria (39.8%), then Firmicutes (30.8%), Actinobacteria (21.1%), Tenericutes (5.1%), and Bacteroidetes (1.6%). The community showed a modest decrease in Firmicutes and increase in Proteobacteria over successive flock rotations. The beetles were relocated within the spent litter to pastureland, where they were found at least 19 weeks later. Over time in the pastureland, their microbial profile underwent a large decrease in the percent of Firmicutes (20.5%). The lesser mealworm showed an ability to survive long-term in the open environment within the spent litter, where their microbiome should be further assessed to both reduce the risk of transferring harmful bacteria, as well as to enhance their contribution when the litter is used as a fertilizer.

Luteimonas deserti sp. nov., a novel strain isolated from desert soil

A Gram-stain-negative, non-motile, rod-shaped bacterial strain, named SJ-16^T, was isolated from desert soil collected in Inner Mongolia, northern PR China. Strain SJ-16^T grew at pH 6.0-11.0 (optimum, pH 8.0-9.0), 4-40 °C (optimum, 30-35 °C) and in the presence of 0-8 % (w/v) NaCl (optimum, 0-2 %). The strain was negative for catalase and positive for oxidase. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain SJ-16^T clustered with Luteimonas chenhongjianii 100111^T and Luteimonas terrae THG-MD21^T, and had 98.8, 98.6, 98.3 and <97.9 % of 16S rRNA gene sequence similarity to strains L. chenhongjianii 100111^T, L. terrae THG-MD21^T, L. aestuarii B9^T and all other type strains of the genus Luteimonas, respectively. The major cellular fatty acids were iso-C_15 : 0, iso-C_16 : 0, summed feature 3 (C_16 : 1  ω7c and/or C_16 : 1  ω6c) and summed feature 9 (C_16 : 0 10-methyl and/or iso-C_17 : 1  ω9c). Diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine were the major polar lipids, and ubiquinone-8 was the only respiratory quinone. The genomic DNA G+C content was 69.3 mol%. The digital DNA-DNA hybridization and average nucleotide identity values of strain SJ-16^T to L. chenhongjianii 100111^T, L. terrae THG-MD21^T, L. rhizosphaerae 4-12^T and L. aestuarii B9^T were 36.9, 37.5, 24.0 and 21.1 %, and 80.9, 80.6, 80.7 and 76.3 %, respectively. Based on phenotypic, physiological and phylogenetic results, strain SJ-16^T represents a novel species of the genus Luteimonas, for which the name Luteimonas deserti is proposed. The type strain is SJ-16^T (=CGMCC 1.17694^T=KCTC 82207^T).

Luteimonas weifangensis sp. nov., Isolated from Bensulfuron-Methyl Contaminated Watermelon Soil

A Gram-stain-negative bacterium, designated WF-2^T, was isolated from bensulfuron-methyl contaminated watermelon soil in Weifang, Shandong province, China. Cells of strain WF-2^T were strictly aerobic, non-motile and rod-shaped. Strain WF-2^T grew optimally at 30 °C, pH 7.0. Strain WF-2^T possessed ubiquinone-8 (Q-8) as the predominant respiratory quinone. The major cellular fatty acids of the strain WF-2^T (> 5.0%) were iso-C_15:0, anteiso-C_15:0, iso-C_16:0, C_16:0, iso-C_17:0, and summed feature 9 (iso-C_17:1 ω9c/C_16:0 10-methyl). The polar lipids consisted of two unidentified lipids, three unidentified phospholipids, phosphatidylglycerol, phosphatidylethanolamine and diphosphatidyl glycolipid. Phylogenetic analysis based on 16S rRNA g^Tne sequences revealed that WF-2^T was a member of the genus Luteimonas and showed the highest sequence similarity to Luteimonas lumbrici 1.1416^T (98.6%) and Lysobacter pocheonensis Gsoil 193^T (97.9%), lower sequence similarity (< 97.0%) to other known species. The genomic DNA G + C content of WF-2^T was 69.2 mol%. Average nucleotide identity (ANI) and the digital DNA-DNA hybridizations (DDH) between strains WF-2^T and L. lumbrici 1.1416^T were 81.9% and 24.7%, respectively. Based on the phylogenetic, chemotaxonomic and phenotypic data presented here, a new species with the name Luteimonas weifangensis sp. nov. is proposed. The type strain is WF-2^T (= KCTC 62441^T = CGMCC 1.13633^T).