High Culturable Bacterial Diversity From a European Desert: The Tabernas Desert

One of the most diverse ecological niches for microbial bioprospecting is soil, including that of drylands. Drylands are one of the most abundant biomes on Earth, but extreme cases, such as deserts, are considered very rare in Europe. The so-called Tabernas Desert is one of the few examples of a desert area in continental Europe, and although some microbial studies have been performed on this region, a comprehensive strategy to maximize the isolation of environmental bacteria has not been conducted to date. We report here a culturomics approach to study the bacterial diversity of this dryland by using a simple strategy consisting of combining different media, using serial dilutions of the nutrients, and using extended incubation times. With this strategy, we were able to set a large (254 strains) collection of bacteria, the majority of which (93%) were identified through 16S ribosomal RNA (rRNA) gene amplification and sequencing. A significant fraction of the collection consisted of Actinobacteria and Proteobacteria, as well as Firmicutes strains. Among the 254 isolates, 37 different genera were represented, and a high number of possible new taxa were identified (31%), of which, three new Kineococcus species. Moreover, 5 out of the 13 genera represented by one isolate were also possible new species. Specifically, the sequences of 80 isolates held a percentage of identity below the 98.7% threshold considered for potentially new species. These strains belonged to 20 genera. Our results reveal a clear link between medium dilution and isolation of new species, highlight the unexploited bacterial biodiversity of the Tabernas Desert, and evidence the potential of simple strategies to yield surprisingly large numbers of diverse, previously unreported, bacterial strains and species.

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Impact of Genotypic Studies on Mycobacterial Taxonomy: the New Mycobacteria of the 1990s

Clinical Microbiology Reviews ◽

10.1128/cmr.16.2.319-354.2003 ◽

2003 ◽

Vol 16 (2) ◽

pp. 319-354 ◽

Cited By ~ 345

Author(s):

Enrico Tortoli

Keyword(s):

New Species ◽

High Performance ◽

Genetic Relatedness ◽

Point Of View ◽

Clinical Samples ◽

Rrna Gene ◽

Cervical Lymph Nodes ◽

Large Numbers ◽

Genetic Techniques ◽

Taxonomic Studies

SUMMARY The advancement of genetic techniques has greatly boosted taxonomic studies in recent years. Within the genus Mycobacterium, 42 new species have been detected since 1990, most of which were grown from clinical samples. Along with species for which relatively large numbers of strains have been reported, some of the new species of mycobacteria have been detected rarely or even only once. From the phenotypic point of view, among the new taxa, chromogens exceed nonchromogens while the numbers of slowly and rapidly growing species are equivalent. Whereas conventional identification tests were usually inconclusive, an important role was played by lipid analyses and in particular by high-performance liquid chromatography. Genotypic investigations based on sequencing of 16S rRNA gene have certainly made the most important contribution. The investigation of genetic relatedness led to the redistribution of the species previously included in the classically known categories of slow and rapid growers into new groupings. Within slow growers, the intermediate branch related to Mycobacterium simiae and the cluster of organisms related to Mycobacterium terrae have been differentiated; among rapid growers, the group of thermotolerant mycobacteria has emerged. The majority of species are resistant to isoniazid and, to a lesser extent, to rifampin. Many of the new species of mycobacteria are potentially pathogenic, and there are numerous reports of their involvement in diseases. Apart from disseminated and localized diseases in immunocompromised patients, the most frequent infections in immunocompetent people involve the lungs, skin, and, in children, cervical lymph nodes. The awareness of such new mycobacteria, far from being a merely speculative exercise, is therefore important for clinicians and microbiologists.

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Bacterial diversity of soil samples from the western Himalayas, India

Canadian Journal of Microbiology ◽

10.1139/w09-011 ◽

2009 ◽

Vol 55 (5) ◽

pp. 564-577 ◽

Cited By ~ 38

Author(s):

Pooja Gangwar ◽

Syed Imteyaz Alam ◽

Sunita Bansod ◽

Lokendra Singh

Keyword(s):

Bacterial Diversity ◽

Bacterial Species ◽

Hydrolytic Enzymes ◽

Soil Samples ◽

Rrna Gene ◽

Organic Carbon Content ◽

Western Himalayas ◽

Bacterial Strains ◽

Culture Independent ◽

The One

High-altitude cold habitats of the Himalayas are little explored with respect to bacterial diversity. Diverse bacterial species and phylotypes obtained by culture-dependent and culture-independent approaches are reported here. Phylogenetic analysis and modulation of bacterial diversity with altitude and available organic carbon content are also described. Psychrophilic and psychrotolerant bacteria dominated the Himalayan habitats, accounting for 60% of the cultivated strains. Isolates produced one or more (up to five) hydrolytic enzymes, lipase being the one secreted by most strains (62%). Partial 16S rRNA gene sequences were obtained for 99 bacterial strains and 74 clones obtained from soil samples from the western Himalayas. Forty-five percent of cultured bacterial strains belonged to the Proteobacteria group with 39% belonging to γ-Proteobacteria. Firmicutes was the second most abundant class with 32% of the total isolates followed by Actinobacteria (16%) and Bacteroidetes (6%). Most of the strains belonged to the genus Bacillus (30%) followed by Pseudomonas (24%) and Arthrobacter (12%). In culture-independent studies, phylotypes belonging to the Proteobacteria were dominant (73%) with the majority being β-Proteobacteria (31%). The bacterial diversity exhibited an altitude gradient with a gradual decline in the number of genera with increase in altitude. The isolates exhibited close phylogenetic affinities to bacteria from other cold habitats.

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Highly parallelized microfluidic droplet cultivation and prioritization on antibiotic producers from complex natural microbial communities

10.1101/2019.12.18.877530 ◽

2019 ◽

Author(s):

Lisa Mahler ◽

Sarah Niehs ◽

Karin Martin ◽

Thomas Weber ◽

Kirstin Scherlach ◽

...

Keyword(s):

Antimicrobial Activity ◽

Natural Products ◽

Bacterial Diversity ◽

High Throughput ◽

High Throughput Screening ◽

Single Cells ◽

Amplicon Sequencing ◽

Droplet Microfluidics ◽

Rrna Gene ◽

Bacterial Strains

AbstractTo investigate the overwhelming part of the bacterial diversity still evading standard cultivation for its potential use in antibiotic synthesis, we have compiled a microscale-cultivation and screening system. We devised a strategy based on droplet-microfluidics taking advantage of the inherent miniaturization and high throughput. Single cells of natural samples were confined in 9 x 106 aqueous droplets and subjected to long-term incubation under controlled conditions. Subsequent a high-throughput screening for antimicrobial natural products was implemented, employing a whole cell reporting system using the viability of reporter strains as a probe for antimicrobial activity. Due to the described microscale cultivation a novel subset of bacterial strains was made available for the following screening for antimicrobials. We demonstrate the merits of the in-droplet cultivation by comparing the cultivation outcome in microfluidic droplets and on conventional agar plates for a bacterial community derived from soil by 16S rRNA gene amplicon sequencing. In-droplet cultivation resulted in a significantly higher bacterial diversity without the common overrepresentation of Firmicutes. Natural strains able to inhibit either a Gram-positive or a Gram-negative reporter strain were isolated from the microscale system and further cultivated. Thereby a variety of rare isolates was obtained. The natural products with antimicrobial activity were elucidated for the most promising candidate. Our method combines a new cultivation approach with a high-throughput search for antibiotic producers to increase the chances of finding new lead substances.

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Marine Bacterium Vibrio sp. CB1-14 Produces Guanidine Alkaloid 6-epi-Monanchorin, Previously Isolated from Marine Polychaete and Sponges

Marine Drugs ◽

10.3390/md17040213 ◽

2019 ◽

Vol 17 (4) ◽

pp. 213 ◽

Cited By ~ 1

Author(s):

Tatyana Makarieva ◽

Larisa Shubina ◽

Valeria Kurilenko ◽

Marina Isaeva ◽

Nadezhda Chernysheva ◽

...

Keyword(s):

New Species ◽

Marine Bacterium ◽

Culture Broth ◽

Rrna Gene ◽

Bacterial Strains ◽

Genome Sequences ◽

16S Rrna Gene Analysis ◽

Chaetopterus Variopedatus ◽

Marine Polychaete ◽

A New Species

Twenty-three bacterial strains were isolated from the secreted mucus trapping net of themarine polychaete Chaetopterus variopedatus (phylum Annelida) and twenty strains were identifiedusing 16S rRNA gene analysis. Strain CB1-14 was recognized as a new species of the genus Vibriousing the eight-gene multilocus sequence analysis (MLSA) and genome sequences of nineteen typeVibrio strains. This Vibrio sp. was cultured, and 6-epi-monanchorin (2), previously isolated from thepolychaete and two sponge species, was found in the cells and culture broth. The presence of the 6-epi-monanchorin was confirmed by its isolation followed by 1H NMR and HRESIMS analysis. Theseresults showed the microbial origin of the bicyclic guanidine alkaloid 2 in C. variopedatus.

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Soil properties and sulfur-oxidizing bacterial diversity in response to different planting patterns of shallot (Allium ascalonicum)

Biodiversitas Journal of Biological Diversity ◽

10.13057/biodiv/d210661 ◽

2020 ◽

Vol 21 (6) ◽

Author(s):

Muhammad Juwanda ◽

SAKHIDIN ◽

SAPARSO ◽

KHARISUN

Keyword(s):

Soil Properties ◽

Bacterial Diversity ◽

Burkholderia Cepacia ◽

Dry Season ◽

Rrna Gene ◽

Rice Soil ◽

Klebsiella Aerogenes ◽

Bacterial Strains ◽

Organic C ◽

Sulfur Oxidizing

Abstract. Juwanda M, Sakhidin, Saparso, Kharisun. 2020. Soil properties and sulfur-oxidizing bacterial diversity in response to different planting patterns of shallot (Allium ascalonicum). Biodiversitas 21: 2832-2839. Sulfur is one of the primary elements required by plants for growth and development. Sulfur-oxidizing bacteria (SOB) can oxidize sulfur to sulfate, which is directly taken up by plant roots. This study aims to evaluate the soil properties and SOB diversity in various shallot planting patterns, i.e. PP1 (shallot-dry season-shallot-shallot), PP2 (shallot-dry season-shallot-rice), and PP3 (shallot-pulses-shallot-rice). Soil samples were collected from the rhizosphere of the shallot plant and analyzed for the soil properties based on the standard methods. Bacteria isolation was cultured on Starkey broth and Starkey agar. Bacteria isolate was identified based on the 16S rRNA gene sequence and compared to the GenBank database. The results showed that shallot planting patterns influence soil properties and SOB diversity. The highest content of sulfate (41.31 ppm), organic C (0.957 %), organic matter (1.650%), C/N ratio (9.57), and SOB diversity was obtained in PP3 planting pattern. Three bacterial strains have been successfully isolated i.e. A-3245D, B-3246F, and C-3247C with their closest related to Burkholderia cepacia, Klebsiella variicola, and Klebsiella aerogenes, respectively. The highest diversity and population density of SOB was in the PP3 planting patterns, i.e Burkholderia cepacia (7.45 x 105 CFU/mL); Klebsiella variicola (1.79 x 107 CFU/mL; Klebsiella aerogenes: 3.9 x 106 CFU/mL). K. variicola can be found in three planting patterns of shallot.

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DIVERSITY OF CULTURABLE BACTERIAL MICROBIOTA OF THE Eisenia foetida DIGESTIVE TRACT

Revista Fitotecnia Mexicana ◽

10.35196/rfm.2018.3.255-264 ◽

2018 ◽

Vol 41 (3) ◽

pp. 255-264 ◽

Cited By ~ 1

Author(s):

J. Abraham Pérez-Pérez ◽

David Espinosa-Victoria ◽

Hilda V. Silva-Rojas ◽

Lucía López-Reyes

Keyword(s):

Bacterial Diversity ◽

Digestive Tract ◽

Bacterial Species ◽

Brain Heart Infusion ◽

Rrna Gene ◽

Eisenia Foetida ◽

Bacterial Isolates ◽

Bacterial Microbiota ◽

Decomposition Of Organic Matter ◽

Earthworm Gut

Bacteria are an unavoidable component of the natural earthworm diet; thus, bacterial diversity in the earthworm gut is directly linked to decomposition of organic matter and development of the surrounding plants. The aim of this research was to isolate and to identify biochemically and molecularly the culturable bacterial microbiota of the digestive tract of Eisenia foetida. Earthworms were sourced from Instituto de Reconversión Productiva y Bioenergética (IRBIO) and Colegio de Postgraduados (COLPOS), México. Bacterial isolation was carried out on plates of Brain Heart Infusion (BHI) culture medium. Fifty six and 44 bacterial isolates were obtained from IRBIO and COLPOS, respectively. The population was composed of 44 Gram-negative and 56 Gram-positive isolates. Over 50 % of the bacterial isolates were rod-shaped cells. The 16S rRNA gene was sequenced and nine genera were identified in worms from IRBIO (Bacillus, Paenibacillus, Solibacillus, Staphylococcus, Arthrobacter, Pantoea, Stenotrophomonas, Acinetobacter and Aeromonas) and six in worms from COLPOS (Bacillus, Paenibacillus, Stenotrophomonas, Staphylococcus, Acinetobacter and Aeromonas). Bacillus was the predominant genus, with eight and six species in the oligochaetes from IRBIO and COLPOS, respectively. The most represented bacteria in the worms from both sites were Bacillus sp. and B. subtilis. The predominance of Bacillus was probably due to spore formation, a reproductive strategy that ensures survival and dispersion in the soil and oligochaetes digestive tract. The gut of E. foetida not only harbored bacterial species of agronomic importance but also species potentially pathogenic for humans (Staphylococcus warneri, Pantoea agglomerans and Stentrophomonas sp.). The larger bacterial diversity in worms from IRBIO could be due to their feeding on cattle manure, which is a rich source of bacteria.

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Campylobacter insulaenigrae bacteremia with meningitis: a case report

BMC Infectious Diseases ◽

10.1186/s12879-021-06353-8 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Moe Kyotani ◽

Tsuneaki Kenzaka ◽

Hozuka Akita ◽

Soichi Arakawa

Keyword(s):

Blood Culture ◽

Marine Mammals ◽

Chronic Subdural Hematoma ◽

16S Rrna Gene Sequencing ◽

Enhancement Effect ◽

Rrna Gene ◽

Clinical Report ◽

Bacterial Strains ◽

Fisher Syndrome ◽

First Case

Abstract Background The bacterium Campylobacter insulaenigrae was first isolated from marine mammals of Scotland in 2004. Only one case of C. insulaenigrae infection in humans has been previously reported. Case presentation An 89-year-old Japanese man without dementia was admitted to our hospital, because he presented with a fever of 38 °C and weakness in right leg since 5 days. He had organized chronic subdural hematoma (CSH), and no history of pre-infection. At the time of admission, he had paralysis of the extraocular muscle, ataxia, and low manual muscle test score of the right side. He was suspected to have Miller Fisher syndrome; however, these symptoms improved without any treatment. On day 22 in the hospital, the patient presented a fever of 38.8 °C, left cranial nerve disorder, and hemiplegia. On day 25, the patient presented with signs of meningeal irritation; cerebrospinal fluid examination indicated an increase in the number of apocytes and a low glucose level. A contrast magnetic resonance imaging (MRI) scan of the patient’s head indicated a contrast enhancement effect in his right meninges. The blood culture showed presence of spirillums; 16S rRNA gene sequencing confirmed that the spirillums in the blood culture were Campylobacter insulaenigrae (C. insulaenigrae). We started treatment with meropenem for bacteremia and meningitis. When the symptoms improved, meropenem was replaced with ampicillin, based on the result of the drug sensitivity test. The treatment continued for 4 weeks. Conclusions We report the first case of meningitis caused by C. insulaenigrae bacteremia in humans, and the second clinical report of C. insulaenigrae infection in humans. The bacterial strains isolated from humans and marine mammals had different genotypes. This suggests that different genotypes could be responsible for differences in the hosts. Further case studies are needed to establish the reasons behind the difference in the manifestations of C. insulaenigrae infections reported so far.

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Microbiome of Odontogenic Abscesses

Microorganisms ◽

10.3390/microorganisms9061307 ◽

2021 ◽

Vol 9 (6) ◽

pp. 1307

Author(s):

Sebastian Böttger ◽

Silke Zechel-Gran ◽

Daniel Schmermund ◽

Philipp Streckbein ◽

Jan-Falco Wilbrand ◽

...

Keyword(s):

16S Rrna ◽

16S Rrna Gene ◽

Oral Microbiome ◽

Minor Role ◽

Rrna Gene ◽

Sequencing Analysis ◽

Bacterial Strains ◽

16S Rrna Gene Analysis ◽

Odontogenic Infections ◽

Odontogenic Abscess

Severe odontogenic abscesses are regularly caused by bacteria of the physiological oral microbiome. However, the culture of these bacteria is often prone to errors and sometimes does not result in any bacterial growth. Furthermore, various authors found completely different bacterial spectra in odontogenic abscesses. Experimental 16S rRNA gene next-generation sequencing analysis was used to identify the microbiome of the saliva and the pus in patients with a severe odontogenic infection. The microbiome of the saliva and the pus was determined for 50 patients with a severe odontogenic abscess. Perimandibular and submandibular abscesses were the most commonly observed diseases at 15 (30%) patients each. Polymicrobial infections were observed in 48 (96%) cases, while the picture of a mono-infection only occurred twice (4%). On average, 31.44 (±12.09) bacterial genera were detected in the pus and 41.32 (±9.00) in the saliva. In most cases, a predominantly anaerobic bacterial spectrum was found in the pus, while saliva showed a similar oral microbiome to healthy individuals. In the majority of cases, odontogenic infections are polymicrobial. Our results indicate that these are mainly caused by anaerobic bacterial strains and that aerobic and facultative anaerobe bacteria seem to play a more minor role than previously described by other authors. The 16S rRNA gene analysis detects significantly more bacteria than conventional methods and molecular methods should therefore become a part of routine diagnostics in medical microbiology.

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Isolation and efficacy of two bacterial strains antagonists of Erwinia amylovora and Pectobacterium carotovorum

Egyptian Journal of Biological Pest Control ◽

10.1186/s41938-021-00443-0 ◽

2021 ◽

Vol 31 (1) ◽

Author(s):

M’hamed BENADA ◽

Boualem BOUMAAZA ◽

Sofiane BOUDALIA ◽

Omar KHALADI

Keyword(s):

Fire Blight ◽

Erwinia Amylovora ◽

Bacterial Species ◽

Crop Protection ◽

Soft Rot ◽

Causal Agent ◽

Plant Diseases ◽

Ecological Niches ◽

Pectobacterium Carotovorum ◽

Bacterial Strains

Abstract Background The development of ecofriendly tools against plant diseases is an important issue in crop protection. Screening and selection process of bacterial strains antagonists of 2 pathogenic bacterial species that limit very important crops, Erwinia amylovora, the causal agent of the fire blight disease, and Pectobacterium carotovorum, the causal agent of bacterial potato soft rot, were reported. Bacterial colonies were isolated from different ecological niches, where both pathogens were found: rhizosphere of potato tubers and fruits and leaves of pear trees from the northwest region of Algeria. Direct and indirect confrontation tests against strains of E. amylovora and P. carotovorum were performed. Results Results showed a significant antagonistic activity against both phytopathogenic species, using direct confrontation method and supernatants of cultures (p<0.005). In vitro assays showed growth inhibitions of both phytopathogenic species. Furthermore, results revealed that the strains of S. plymuthica had a better inhibitory effect than the strains of P. fluorescens against both pathogens. In vivo results on immature pear fruits showed a significant decrease in the progression of the fire blight symptoms, with a variation in the infection index from one antagonistic strain to another between 31.3 and 50%, and slice of potato showed total inhibition of the pathogen (P. carotovorum) by the antagonistic strains of Serratia plymuthica (p<0.005). Conclusion This study highlighted that the effective bacteria did not show any infection signs towards plant tissue, and considered as a potential strategy to limit the fire blight and soft rot diseases.

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Spatial and Temporal Variation in Microbial Diversity and Community Structure in a Contaminated Mangrove Wetland

Applied Sciences ◽

10.3390/app10175850 ◽

2020 ◽

Vol 10 (17) ◽

pp. 5850

Author(s):

Jiaojiao Ma ◽

Ting Zhou ◽

Chunyu Xu ◽

Dawen Shen ◽

Songjun Xu ◽

...

Keyword(s):

Community Structure ◽

Spatial Variation ◽

Temporal Variation ◽

Bacterial Diversity ◽

Diversity Index ◽

Total Carbon ◽

Spatial And Temporal Variation ◽

Rrna Gene ◽

Mangrove Wetland ◽

Mangrove Soils

Field and laboratory investigations were conducted to characterize bacterial diversity and community structure in a badly contaminated mangrove wetland adjacent to the metropolitan area of a megacity in subtropical China. Next-generation sequencing technique was used for sequencing the V4–V5 region of the 16s rRNA gene on the Illumina system. Collectively, Proteobacteria, Chloroflexi, Planctomycetes, Actinobacteria and Bacteroidetes were the predominant phyla identified in the investigated soils. A significant spatial variation in bacterial diversity and community structure was observed for the investigated mangrove soils. Heavy metal pollution played a key role in reducing the bacterial diversity. The spatial variation in soil-borne heavy metals shaped the spatial variation in bacterial diversity and community structure in the study area. Other environmental factors such as total carbon and total nitrogen in the soils that are affected by seasonal change in temperature could also influence the bacterial abundance, diversity and community structure though the temporal variation was relatively weaker, as compared to spatial variation. The bacterial diversity index was lower in the investigated site than in the comparable reference site with less contaminated status. The community structure in mangrove soils at the current study site was, to a remarkable extent, different from those in the tropical mangrove wetlands around the world.

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