Ecology and resistance to UV light and antibiotics of microbial communities on UV cabins in the dermatology service of a Spanish hospital

Microorganisms colonize all possible ecological habitats, including those subjected to harsh stressors such as UV radiation. Hospitals, in particular the UV cabins used in phototherapy units, constitute an environment in which microbes are intermittently subjected to UV irradiation. This selective pressure, in addition to the frequent use of antibiotics by patients, may represent a threat in the context of the increasing problem of antimicrobial resistance. In this work, a collection of microorganisms has been established in order to study the microbiota associated to the inner and outer surfaces of UV cabins and to assess their resistance to UV light and the antibiotics frequently used in the Dermatology Service of a Spanish hospital. Our results show that UV cabins harbor a relatively diverse biocenosis dominated by typically UV-resistant microorganisms commonly found in sun-irradiated environments, such as Kocuria, Micrococcus or Deinococcus spp., but also clinically relevant taxa, such as Staphylococcus or Pseudomonas spp. The UV-radiation assays revealed that, although some isolates displayed some resistance, UV is not a major factor shaping the biocenosis living on the cabins, since a similar pool of resistant microorganisms was identified on the external surface of the cabins. Interestingly, some Staphylococcus spp. displayed resistance to one or more antibiotics, although the hospital reported no cases of antibiotic-resistance infections of the patients using the cabins. Finally, no association between UV and antibiotic resistances was found.

Exploring Diversity and Polymer Degrading Potential of Epiphytic Bacteria Isolated from Marine Macroalgae

The macroalgae surface allows specific bacterial communities to colonize, resulting in complex biological interactions. In recent years, several researchers have studied the diversity and function of the epiphytic bacteria associated with algal host, but largely these interactions remain underexplored. In the present study we analysed the cultivable diversity and polymer degradation potential of epiphytic bacteria associated with five different marine macroalgae (Sargassum, Ulva, Padina, Dictyota and Pterocladia sp.) sampled from the central west coast of India. Out of the total 360 strains isolated, purified and preserved, about 238 strains were identified through 16S rRNA gene sequence analysis and processed for polymer (cellulose, pectin, xylan and starch) degrading activities. Phylogeny placed the strains within the classes Actinobacteria, Bacilli, Alpha-proteobacteria, and Gamma-proteobacteria and clustered them into 45 genera, wherein Vibrio, Bacillus, Pseudoalteromonas, Alteromonas, Staphylococcus and Kocuria spp. were the most abundant with 20 strains identified as potentially novel taxa within the genera Bacillus, Cellulosimicrobium, Gordonia, Marinomonas, Vibrio, Luteimonas and Pseudoalteromonas. In terms of polymer hydrolysis potential, 61.3% had xylanase activity, while 59.7%, 58.8%, and 52.2% had amylase, cellulase, and pectinase activity, respectively. Overall, 75.6% of the strains degraded more than one polysaccharide, 24% degraded all polymers, while nine strains (3.8%) degraded raw sugarcane bagasse. This study showed great potential for seaweed-associated bacteria in the bio-remediation of agro-waste based raw materials, which can be employed in the form of green technology.

Characterization and Transferability of erm and tet Antibiotic Resistance Genes in Lactobacillus spp. Isolated from Traditional Fermented Milk

Lactobacillus is a widely used bacteria and consumed through various fermented foods and beverages. Strains have been shown to carry resistance genes and mobile genetic elements with their ability to transfer the resistance to sensitive pathogenic strains. To study this, 4 cultures of Lactobacillus were isolated from traditional fermented milk. The isolates were able to grow up to 4% (w/v) NaCl concentration and 45 °C temperature, and showed > 97% 16S rRNA gene similarities with Lactobacillus fermentum. All the isolates were phenotypically screened for the presence of antibiotic resistance. Minimum inhibitory concentration (MIC) as microbiological breakpoints were observed against a varied class of antibiotics. Isolates AKO 94.6, DVM 95.7, and NIFTEM 95.8 were explicitly resistant to ampicillin, ciprofloxacin and vancomycin with MIC well beyond the maximum range of 256 µg/ml in the E-strip test. While isolate SKL1 was sensitive to ampicillin and showed MIC at 0.25 µg/ml but resistant to streptomycin and trimethoprim (MIC > 256 µg/ml). Molecular characterization showed the presence of tet(M) gene in three isolates SKL1, DVM 95.7, and NIFTEM 95.8 which was chromosomally associated resistance determinants while erm(B) resistance gene was detected in isolates DVM 95.7 and NIFTEM 95.8 only which was a plasmid associated gene and could be transferrable conjugally. Gene for Tn916 family (xis) was also observed in isolates DVM 95.7 and NIFTEM 95.8. Transferability of antibiotic resistance to pathogenic recipient strains was examined in isolates DVM 95.7 and NIFTEM 95.8 in different food matrices. The highest conjugation frequency with ~ 10^-1 was obtained in alfalfa seed sprouts. This study reports the presence of acquired gene resistance in Lactobacillus species and dissemination to susceptible strains of bacteria in different food matrices. 16S rRNA gene sequences of isolates were uploaded to the NCBI GenBank database to retrieve the accession number.

Yangia mangrovi sp. nov., a novel member of the Roseobacter clade isolated from mangrove soil and emended description of Yangia pacifica Dai et al. 2006

During a study of the bacterial diversity of mangrove habitats, a novel Gram-stain-negative, rod-shaped bacterium designated as SAOS 153D^T was isolated. Sequence alignment and molecular phylogenetic analyses based on 16S rRNA and core gene sequence of strain SAOS 153D^T with closely related taxa revealed a sequence identity of 99.4 % and clustering with Yangia pacifica DX5-10^T. The fatty acids summed feature 8 (C_18:1 ω7c/C_18:1 ω6c) and the lipids phosphatidylglycerol, phosphatidylethanolamine and an unknown phospholipid were the major components of the cell wall. The only ubiquinone type present was Q-10. The genomic DNA G+C content of the strain calculated from whole genome sequencing was 66.9 mol%. These chemotaxonomic and genomic characteristics supported the molecular phylogenetic analysis and placed the strain well within the radiation of the genus Yangia. The overall genome related indices using digital DNA-DNA hybridization (35.4 %) and ortho-average nucleotide identity (88.1 %) values were much lower than the recommended thresholds for species delineation, which further consolidated the novel species status of strain SAOS 153D^T within the genus Yangia as Yangia mangrovi sp. nov. The type strain is SAOS 153D^T (=JCM 31345^T=KCTC 52280^T=MTCC 12749^T).

Halomonas icarae sp. nov., a moderately halophilic bacterium isolated from beach soil in India

A moderately halophilic, Gram-stain-negative, aerobic bacterium, strain D1-1^T, belonging to the genus Halomonas, was isolated from soil sampled at Pentha beach, Odisha, India. Phylogenetic trees reconstructed based on 16S rRNA genes and multilocus sequence analysis of gyrB and rpoD genes revealed that strain D1-1^T belonged to the genus Halomonas and was most closely related to Halomonas alimentaria YKJ-16^T (98.1 %) followed by Halomonas ventosae Al12^T (97.5 %), Halomonas sediminicola CPS11^T (97.5 %), Halomonas fontilapidosi 5CR^T (97.4 %) and Halomonas halodenitrificans DSM 735^T (97.2 %) on the basis of 16S rRNA gene sequence similarity. Sequence identities with other species within the genus were lower than 97.0 %. The digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values of 22.4-30 % and 79.5-85.4 % with close relatives of H. halodenitrificans DSM 735^T, H. alimentaria YKJ-16^T, H. ventosae Al12^T and H. fontilapidosi 5CR^T were lower than the threshold recommended for species delineation (70 % and 95-96 % for dDDH and ANI, respectively). Further, strain D1-1^T formed yellow-coloured colonies; cells were rod-shaped, motile with optimum growth at 30 °C (range, 4-45 °C) and 2-8 % NaCl (w/v; grew up to 24 % NaCl). The major fatty acids were summed feature 8 (C_18 : 1  ω7c/C_18 : 1  ω6c), summed feature 3 (C_16 : 1  ω7c/C_16 : 1  ω6c) and C_16 : 0 and the main respiratory quinone was ubiquinone Q-9 in line with description of the genus. Based on its chemotaxonomic and phylogenetic characteristics and genome uniqueness, strain D1-1^T represents a novel species in the genus Halomonas, for which we propose the name Halomonas icarae sp. nov., within the family Halomonadaceae. The type strain is D1-1^T (=JCM 33602^T=KACC 21317^T=NAIMCC-B-2254^T).

Indiicoccus explosivorum gen. nov., sp. nov., isolated from an explosives waste contaminated site

A pink-pigmented, Gram-stain-positive, aerobic, coccoid-shaped bacterial strain, designated as S5-TSA-19^T, was isolated from an explosives contaminated site in Panchkula, Haryana, India. The 16S rRNA gene sequencing blast analysis indicated that the strain is a member of the family Planococcaceae with the highest sequence similarity to Planomicrobium soli XN13^T (96.1 %), followed by Planococcus maitriensis S1^T (95.6 %), Planococcus plakortidis DSM 23997^T (95.6 %), Planomicrobium flavidum ISL-41^T (95.6 %), Planococcus rifietoensis M8^T (95.5 %), Planococcus salinus LCB217^T (95.5 %) and Planococcus maritimus DSM 17275^T (95.5 %). Phylogenetic analysis based on 16S rRNA gene and whole-genome sequences (based on a conserved set of 400 proteins) retrieved the strain in a distinct branch indicating a separate lineage within the family Planococcaceae. Strain S5-TSA-19^T had a distinctive chemotaxonomic pattern comprising A4α type peptidoglycan based on l-Lys-d-Asp, iso-C15 : 0 as the major fatty acid, absence of phosphatidylethanolamine as a major lipid and MK-7 and MK-6 as the major menaquinones, differentiating it from the genera Planococcus and Planomicrobium, thus supporting the findings of molecular phylogeny. Further, strain S5-TSA-19^T was able to biotransform hexahydro-1,3,5,-trinitro-1,2,5-triazine (RDX) into nitrite derivatives under aerobic conditions in 2-4 days, whereas the closest reference strains did not possess this property. On the basis of polyphasic taxonomic characterization and a phylogenomics approach, strain S5-TSA-19^T is proposed as the type strain of a novel species in a novel genus for which the name Indiicoccus explosivorum gen. nov., sp. nov. is proposed (=JCM 31737^T=KCTC 33871^T=MTCC 12608^T).