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Antibiotics are an essential part of modern medicine. The emergence of antibiotic‐resistant mutants among bacteria is seemingly inevitable, and results, within a few decades, in decreased efficacy and withdrawal of the antibiotic from widespread usage. The traditional answer to this problem has been to introduce new antibiotics that kill the resistant mutants. Unfortunately, after more than 50 years of success, the pharmaceutical industry is now producing too few antibiotics, particularly against Gram‐negative organisms, to replace antibiotics that are no longer effective for many types of infection. This paper reviews possible new ways to discover novel antibiotics. The genomics route has proven to be target rich, but has not led to the introduction of a marketed antibiotic as yet. Non‐culturable bacteria may be an alternative source of new antibiotics. Bacteriophages have been shown to be antibacterial in animals, and may find use in specific infectious diseases. Developing new antibiotics that target non‐multiplying bacteria is another approach that may lead to drugs that reduce the emergence of antibiotic resistance and increase patient compliance by shortening the duration of antibiotic therapy. These new discovery routes have given rise to compounds that are in preclinical development, but, with one exception, have not yet entered clinical trials. For the time being, the majority of new antibiotics that reach the marketplace are likely to be structural analogues of existing families of antibiotics or new compounds, both natural and non‐natural which are screened in a conventional way against live multiplying bacteria. British Journal of Pharmacology (2007) 152, 1147–1154; doi:10.1038/sj.bjp.0707432; published online 20 August 2007

The results of the study on the characteristics of the viable (culturable) and total bacterial particles in the ambient air in Gliwice, Poland, are presented. The concentration of viable bacteria in the air ranged from 57 CFU m−3 (Colony Forming Units per cubic meter) during winter to 305 CFU m−3 in spring, while the concentration of all bacteria (live and dead) in the air, measured in selected days, ranged from 298 cells m−3 in winter to over 25 thousand per m3 in autumn. A field study was also carried out to find out the level of the sterilization rate (k) for airborne bacteria. The obtained value of k for viable bacteria exposed to UV solar radiation in Gliwice was approximately 10 cm2 W−1s−1. The patterns of the size distributions of viable bacteria found in three seasons, spring, summer, and autumn, were similar, showing a peak in the range of 3.3–4.7 µm. In the winter season, the main peak was shifted into the smaller particles with an aerodynamic diameter ranging from 2.1 to 4.7 µm. The dominant group of culturable bacteria within the studied period was Gram-positive rods-forming endospores (34–55%), while the least frequent were Gram-negative rods (2%). This research can be used to assess the health effects of exposure to bacterial aerosols in people living in this area.

The occurrence and reactivation of viable but non-culturable (VBNC) Escherichia coli after different anaerobic digestions and the subsequent dewatering and storage were evaluated and compared. Culturable E. coli in digested sludge increased by two to four orders of magnitudes immediately after dewatering. However, counts of both the total and viable E. coli indicated that the increase of E. coli was attributed to its reactivation from the VBNC state to the culturable state. The VBNC pathogen incidences of thermophilic digestion were two to three orders of magnitude higher than those of mesophilic digestion. Accordingly, culturable E. coli in thermophilic, digested sludge after storage were one order of magnitude higher than mesophilic digestion. Anaerobic digestion thus mainly alters the culturable state of pathogens rather than killing them; therefore the biological safety of digested sludge, especially temperature-phased anaerobic digestion, should be carefully assessed.

Coastal bacteria play an important role in the conversion of terrestrial organic carbon (TerrOC). However, their ecological patterns and drivers remains elusive. Here, 180 bacterial communities from 10 regions along the Chinese coastline, covering an 18 000 km transect between 18.27°N and 39.82°N, were cultured under three typical lignocellulosic substrates, hardwood (aspen), softwood (pine), and herbaceous (rice straw), respectively. All the consortia showed a broad spectrum of TerrOC utilization, and displayed degradation capacities comparable with those previously established though preliminary in situ lignocellulose enrichment. Moreover, following the metabolic theory of ecology, annual average temperature of the sites stimulated community metabolism, even though all were cultured at 30°C. Consortia enriched on aspen exhibited the highest temperature sensitivity. 16S rRNA gene amplicon and metatranscriptomic sequencing analyses revealed temperature-dependent latitudinal diversity gradients, displaying a trend that was opposite of the temperature-diversity positive relationship observed in terrestrial lignin-degrading microbes. The community composition shifted to adapt to rising environmental temperature. To enhance lignin degradation, aspen consortia from high annual average temperature employed metabolic generalists, which induced expression of dypB centered gene families for lignin depolymerization and versatile pathways for degradation of lignin derivates. This study reveals the intrinsic drivers for coastal cultured lignocellulose degrading bacterial communities from an ecological perspective and deepens our understanding of the metabolic mechanisms in coastal TerrOC conversion.

Background Understanding pairwise bacterial interactions in the human gut is crucial for deciphering the complex networks of bacterial interactions and their contributions to host health. However, there is a lack of large-scale experiments focusing on bacterial interactions within the human gut microbiome. Methods We investigated the pairwise interactions of 113 bacterial strains isolated from healthy Chinese volunteers, selected for their high abundance and functional representation of the human gut microbiome. Using mGAM agar plates, a rich medium designed to maintain community structure, we established the “PairInteraX” dataset, which includes 3233 pair combinations of culturable human gut bacteria. This dataset was analyzed to identify interaction patterns and the key factors influencing these patterns. Results Our analysis revealed that negative interactions were predominant among the bacteria in the PairInteraX dataset. When combined with in vivo gut metagenome datasets, we noted a diminishing mutualism and an increasing competition as microbial abundances increased; consequently, the maintenance of community diversity requires the participation of various types of interactions, especially the negative interactions. We also identified key factors influencing these interaction patterns including metabolic capacity and motility. Conclusions This study provides a comprehensive overview of pairwise bacterial interactions within the human gut microbiome, revealing a dominance of negative interactions. Besides, metabolic capacity and motility were identified as the key factors to influence the pairwise interaction patterns. This large-scale dataset and analysis offer valuable insights for further research on microbial community dynamics and their implications for host health. CQqVLhf9exYcCHQM3rrN7j Video Abstract

Numerous studies have focused on occupational and indoor environments because people spend more than 90% of their time in them. Nevertheless, air is the main source of bacteria in indoors, and outdoor exposure is also crucial. Worldwide studies have indicated that bacterial concentrations vary among different types of outdoor environments, with considerable seasonal variations as well. Conducting comprehensive monitoring of atmospheric aerosol concentrations is very important not only for environmental management but also for the assessment of the health impacts of air pollution. To our knowledge, this is the first study to present outdoor and seasonal changes of bioaerosol data regarding an urban area of Poland. This study aimed to characterize culturable bacteria populations present in outdoor air in Gliwice, Upper Silesia Region, Poland, over the course of four seasons (spring, summer, autumn and winter) through quantification and identification procedures. In this study, the samples of bioaerosol were collected using a six-stage Andersen cascade impactor (with aerodynamic cut-off diameters of 7.0, 4.7, 3.3, 2.1, 1.1 and 0.65 μm). Results showed that the concentration of airborne bacteria ranged from 4 CFU m −3 , measured on one winter day, to a maximum equal to 669 CFU m −3 on a spring day. The average size of culturable bacterial aerosol over the study period was 199 CFU m −3 . The maximal seasonally averaged concentration was found in the spring season and reached 306 CFU m −3 , and the minimal seasonally averaged concentration was found in the winter 49 CFU m −3 . The most prevalent bacteria found outdoors were gram-positive rods that form endospores. Statistically, the most important meteorological factors related to the viability of airborne bacteria were temperature and UV radiation. These results may contribute to the promotion and implementation of preventative public health programmes and the formulation of recommendations aimed at providing healthier outdoor environments.

Abstract Bacteria are an essential biotic component in freshwater environments. A group of 262 bacterial strains of freshwater environments from an altitudinal gradient in the Eastern Cordillera of Colombia was identified using the 16S rRNA gene sequence analysis. Hill numbers and related diversity indices were calculated to know the bacteria diversity in this collection and environments. In addition, the Bray–Curtis index was also calculated to know the differences in genera composition between sampled localities and their relationship with altitudinal gradient. The identified bacterial strains were grouped into 7 major phylogenetic groups (Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Flavobacteriia, Actinomycetes, Clostridia, and Bacilli), 38 genera, and 84 distinctive species. Diversity analysis based on Hill numbers showed that the diversity concerning bacteria inhabiting freshwater environments was consistently high. Dominant genera were Klebsiella, Serratia, and Pseudomonas, although other genera such as Bacillus, Lelliottia, and Obesumbacterium were well represented per locality. The highest bacterial diversity came from localities Cimitarra and El Carmen del Chucurí, while those originating from Santa Bárbara and Páramo del Almorzadero were relatively lower diverse. Differences in diversity were found to be mainly due to the spatial replacement of one genus by another and, to a lesser extent, to the loss or gain of taxa. The study provides new information on factors that modulate the variation of cultivable bacterial composition in neotropics freshwater environments.

Bl. is a medicinal-edible heterotrophic orchid with distinct vertical distribution, but unstable yield and inconsistent quality in cultivation limit its industrial development. The mechanisms by which altitude modulates growth and bioactive compound accumulation in different forms remain unclear. We conducted a two-factor field experiment (two forms: f.  , f. ; three altitudes: 650, 1653, 1953 m) in the Qinba Mountains, using a consistent commercial . strain to isolate bacterial effects. We analyzed microclimate, soil properties, soil enzyme activities, culturable bacterial communities, and tuber bioactive compounds (gastrodin, parishins) across developmental stages. Form-specific altitudinal responses were observed: total yield peaked at high altitude (1953 m; 2668.11 ± 317.10 g), while bioactive compounds were enriched at middle altitude (1653 m)-with optimal accumulation at the Large stage (f. ) and stage (f. ). Soil pH was the primary correlative factor for f. quality (explaining 52%-70.5% of variation in RDAs), whereas integrated carbon-acquiring enzyme activity (16.6%) was key for f. -consistent with PLS-SEM evidence of an indirect \"soil properties→enzyme activities\" pathway for f. quality. Culturable tuber-associated bacteria (dominated by Pseudomonadota, least diverse at middle altitude) correlated divergently with yield and quality: positively with yield but negatively with quality in f. ; weakly positive with yield and strongly (non-significantly) positive with quality in f. (  < 0.05). Our findings clarify form-specific correlative networks linking altitude, microenvironment, soil microbes, and plant performance, providing targeted guidance for ecological cultivation to balance high yield and quality in .

Background Populus euphratica Olivier is a kind of tree capable of growing in extremely arid desert and semi-desert environments. In this study, a culture-dependent method was used to analyze the bacterial diversity of stem liquid of P. euphratica and resina of P. euphratica , and to further evaluate plant growth promoting (PGP) activity. Results A total of 434 bacteria were isolated from stem fluid and resina of P. euphratica in Ebinur Lake Wetland Nature Reserve and Mulei Primitive forest. The results of taxonomic composition analysis shows that Gammaproteobacteria, Firmicutes, and Actinobacteria_c are the three dominant groups in all the communities, and the representative genera are Bacillus , Nesterenkonia and Halomonas . The diversity analysis shows that the culturable bacterial community diversity of P. euphratica in Ebinur Lake Wetland Nature Reserve is higher than that in Mulei Primitive forest, and the bacterial community diversity of P. euphratica stem fluid is higher than that of resina. According to PGP activity evaluation, 158 functional bacteria with plant growth promoting potential were screened. Among them, 61 strains havephosphorus solubilizing abilities, 80 strains have potassium solubilizing abilities, 32 strains have nitrogen fixation abilities, and 151 strains have iron ammonia salt utilization abilities. The germination rate, plant height, and dry weight of the maize seedlings treated with strains BB33-1, TC10 and RC6 are significantly higher than those of the control group. Conclusion In this study, a large number of culturable bacteria were isolated from P. euphratica , which provides new functional bacteria sources for promoting plant growth.

Background The microbiota has been shown to play an important role in the biology of insects. In recent decades, significant efforts have been made to better understand the diversity of symbiotic bacteria associated with mosquitoes and assess their influence on pathogen transmission. Here, we report the bacterial composition found in field-caught Aedes albopictus populations by using culture-dependent methods. Results A total of 104 mosquito imagos (56 males and 48 females) were caught from four contrasting biotopes of Madagascar and their bacterial contents were screened by plating whole body homogenates on three different culture media. From 281 bacterial colony types obtained, amplified ribosomal DNA restriction analysis (ARDRA) showed they had 40 distinct ribotypes. Sequencing and BLAST analysis of the 16S rDNA genes responsible for each representative profile made it possible to identify 27 genera distributed in three major phyla. In female mosquitoes, bacterial isolates were mostly Proteobacteria (51.3%) followed by Firmicutes (30.3%) and Actinobacteria (18.4%). Conversely, Actinobacteria was the most abundant phylum in male mosquitoes (48%) followed by Proteobacteria (30.6%) and Firmicutes (20.4%). The relative abundance and composition of isolates also varied between sampling sites, ranging from 3 distinct families in Ankazobe to 8 in Tsimbazaza Park, and Toamasina and Ambohidratrimo. Pantoea was the most common genus in both females and males from all sampling sites, except for Ambohidratrimo. No differences in genome size were found between Pantoea isolates from mosquitoes and reference strains in pulse field gel electrophoresis. However, according to the numbers and sizes of plasmids, mosquito isolates clustered into three different groups with other strains isolated from insects but distinct from isolates from the environment. Conclusions The recent upsurge in research into the functional role of the insect microbiota prompts the interest to better explore the role some bacteria detected here may have in the mosquito biology. Future studies of culturable bacteria might decipher whether they have a biological role in the invasiveness of Ae. albopictus . As a possible candidate for paratransgenesis, the predominant genus Pantoea will be characterized to better understand its genetic contents and any possible influence it may have on vector competence of Ae. albopictus .