Higher diversity of sulfur-oxidizing bacteria based on soxB gene sequencing in surface water than in spring in Wudalianchi volcanic group, NE China

INTRODUCTION

Sulfur-oxidizing bacteria (SOB) play a key role in the biogeochemical cycling of sulfur.

OBJECTIVES

To explore SOB diversity, distribution, and physicochemical drivers in five volcanic lakes and two springs in the Wudalianchi volcanic field, China.

METHODS

This study analyzed microbial communities in samples via high-throughput sequencing of the soxB gene. Physical-chemical parameters were measured, and QIIME 2 (v2019.4), R, Vsearch, MEGA7, and Mothur processed the data. Alpha diversity indices and UPGMA clustering assessed community differences, while heat maps visualized intra-sample variations. Canoco 5.0 analyzed community-environment correlations, and NMDS, Adonis, and PcoA explored sample dissimilarities and environmental factor correlations. SPSS v.18.0 tested for statistical significance.

RESULTS

The diversity of SOB in surface water was higher than in springs (more than 7.27 times). We detected SOB affiliated to β-proteobacteria (72.3 %), α-proteobacteria (22.8 %), and γ-proteobacteria (4.2 %) distributed widely in these lakes and springs. Rhodoferax and Cupriavidus were most frequent in all water samples, while Rhodoferax and Bradyrhizobium are dominant in surface waters but rare in springs. SOB genera in both habitats were positively correlated. Co-occurrence analysis identified Bradyrhizobium, Blastochloris, Methylibium, and Metyhlobacterium as potential keystone taxa. Redundancy analysis (RDA) revealed positive correlations between SOB diversity and total carbon (TC), Fe2+, and total nitrogen (TN) in all water samples.

CONCLUSION

The diversity and community structure of SOB in volcanic lakes and springs in the Wudalianchi volcanic group were clarified. Moreover, the diversity and abundance of SOB decreased with the variation of water openness, from open lakes to semi-enclosed lakes and enclosed lakes.

An efflux pump in genomic island GI-M202a mediates the transfer of polymyxin B resistance in Pandoraea pnomenusa M202

BACKGROUND

Polymyxin B is considered a last-line therapeutic option against multidrug-resistant gram-negative bacteria, especially in COVID-19 coinfections or other serious infections. However, the risk of antimicrobial resistance and its spread to the environment should be brought to the forefront.

METHODS

Pandoraea pnomenusa M202 was isolated under selection with 8 mg/L polymyxin B from hospital sewage and then was sequenced by the PacBio RS II and Illumina HiSeq 4000 platforms. Mating experiments were performed to evaluate the transfer of the major facilitator superfamily (MFS) transporter in genomic islands (GIs) to Escherichia coli 25DN. The recombinant E. coli strain Mrc-3 harboring MFS transporter encoding gene FKQ53_RS21695 was also constructed. The influence of efflux pump inhibitors (EPIs) on MICs was determined. The mechanism of polymyxin B excretion mediated by FKQ53_RS21695 was investigated by Discovery Studio 2.0 based on homology modeling.

RESULTS

The MIC of polymyxin B for the multidrug-resistant bacterial strain P. pnomenusa M202, isolated from hospital sewage, was 96 mg/L. GI-M202a, harboring an MFS transporter-encoding gene and conjugative transfer protein-encoding genes of the type IV secretion system, was identified in P. pnomenusa M202. The mating experiment between M202 and E. coli 25DN reflected the transferability of polymyxin B resistance via GI-M202a. EPI and heterogeneous expression assays also suggested that the MFS transporter gene FKQ53_RS21695 in GI-M202a was responsible for polymyxin B resistance. Molecular docking revealed that the polymyxin B fatty acyl group inserts into the hydrophobic region of the transmembrane core with Pi-alkyl and unfavorable bump interactions, and then polymyxin B rotates around Tyr43 to externally display the peptide group during the efflux process, accompanied by an inward-to-outward conformational change in the MFS transporter. Additionally, verapamil and CCCP exhibited significant inhibition via competition for binding sites.

CONCLUSIONS

These findings demonstrated that GI-M202a along with the MFS transporter FKQ53_RS21695 in P. pnomenusa M202 could mediate the transmission of polymyxin B resistance.

Alterations of gut and oral microbiota in the individuals consuming take-away food in disposable plastic containers

Microplastics (MP) and nanoplastics (NP) exist in the disposable plastic take-away containers. This study aims to determine the gut and oral microbiota alterations in the individuals frequently and occasionally consuming take-away food in disposable plastic containers (TFDPC), and explore the effect of micro/nanoplastics (MNP) reduction on gut microbiota in mice. TFDPC consumption are associated with greater presences of gastrointestinal dysfunction and cough. Both occasional and frequent consumers have altered gut and oral microbiota, and their gut diversity and evenness are greater than those of non-TFDPC consuming cohort. Multiple gut and oral bacteria are associated with TFDPC consumers, among which intestinal Collinsella and oral Thiobacillus are most associated with the frequent consumers, while intestinal Faecalibacterium is most associated with the occasional consumers. Although some gut bacteria associated with the mice treated with 500 µg NP and 500 µg MP are decreased in the mice treated with 200 µg NP, the gut microbiota of the three MNP groups are all different from the control group. This study demonstrates that TFDPC induces gut and oral microbiota alterations in the consumers, and partial reduction of the size and amount of MNP cannot rectify the MNP-induced gut microbial dysbiosis.

Summary of Novel Bacterial Isolates Derived from Human Clinical Specimens and Nomenclature Revisions Published in 2018 and 2019

Knowledge of novel prokaryotic taxon discovery and nomenclature revisions is of importance to clinical microbiology laboratory practice, infectious disease epidemiology, and studies of microbial pathogenesis. Relative to bacterial isolates derived from human clinical specimens, we present an in-depth summary of novel taxonomic designations and revisions to prokaryotic taxonomy that were published in 2018 and 2019. Included are several changes pertinent to former designations of or within Propionibacterium spp., Corynebacterium spp., Clostridium spp., Mycoplasma spp., Methylobacterium spp., and Enterobacteriaceae Future efforts to ascertain clinical relevance for many of these changes may be augmented by a document development committee that has been appointed by the Clinical and Laboratory Standards Institute.

Complete Genome Sequences of Clinical Pandoraea fibrosis Isolates

Pandoraea fibrosis is a newly identified Gram-negative bacterial species that was isolated from the respiratory tract of an Australian cystic fibrosis patient. The complete assembled genome sequences of two consecutive isolates (second isolate collected 11 months after antibiotic treatment) from the same individual are presented here.

Structured surveillance of Achromobacter, Pandoraea and Ralstonia species from patients in England with cystic fibrosis

A structured survey of the cystic fibrosis pathogens Achromobacter, Pandoraea and Ralstonia species from thirteen sentinel hospitals throughout England was undertaken by Public Health England. One isolate per patient of these genera collected from CF patients during the seven-month survey period in 2015 was requested from participating hospitals. Species-level identification was performed using nrdA/gyrB sequence cluster analysis, and genotyping by pulsed-field gel electrophoresis. In total, 176 isolates were included in the survey; 138 Achromobacter spp. (78.4%), 29 Pandoraea spp. (16.5%) and 9 Ralstonia spp. (5.1%). Novel Achromobacter and Pandoraea clusters were identified. High levels of antimicrobial resistance were found, particularly among Pandoraea isolates. Genotyping analysis revealed considerable diversity, however one geographically-widespread cluster of A. xylosoxidans isolates from six hospitals was found, in addition to two other clusters, both comprising isolates from two hospitals, either derived from the same region (A. xylosoxidans), or from hospitals within the same city (P. apista).

Whole-genome analysis of Pandoraea species strains from cystic fibrosis patients

Aim: Genetic characterization of Pandoraea strains recovered from cystic fibrosis patients. Materials & methods: The whole-genome sequence of 12 Pandoraea strains was determined using Illumina technology. The position of the strains within the genus Pandoraea was analyzed using selected partial gene sequences, core genome multi-locus sequence typing and average nucleotide identity analysis. Furthermore, the sequences were annotated. Results: The results show that some strains previously identified as Pandoraea pnomenusa, Pandoraea sputorum, Pandoraea oxalativorans and Pandoraea pulmonicola belong to novel species. The strains did not harbor acquired antibiotic resistance genes but encoded an OXA-type ß-lactamase. Conclusion: The taxonomy of the genus Pandoraea needs to be revised.

Comparative Genomics of Pandoraea, a Genus Enriched in Xenobiotic Biodegradation and Metabolism

Comparative analysis of partial gyrB, recA, and gltB gene sequences of 84 Pandoraea reference strains and field isolates revealed several clusters that included no taxonomic reference strains. The gyrB, recA, and gltB phylogenetic trees were used to select 27 strains for whole-genome sequence analysis and for a comparative genomics study that also included 41 publicly available Pandoraea genome sequences. The phylogenomic analyses included a Genome BLAST Distance Phylogeny approach to calculate pairwise digital DNA–DNA hybridization values and their confidence intervals, average nucleotide identity analyses using the OrthoANIu algorithm, and a whole-genome phylogeny reconstruction based on 107 single-copy core genes using bcgTree. These analyses, along with subsequent chemotaxonomic and traditional phenotypic analyses, revealed the presence of 17 novel Pandoraea species among the strains analyzed, and allowed the identification of several unclassified Pandoraea strains reported in the literature. The genus Pandoraea has an open pan genome that includes many orthogroups in the ‘Xenobiotics biodegradation and metabolism’ KEGG pathway, which likely explains the enrichment of these species in polluted soils and participation in the biodegradation of complex organic substances. We propose to formally classify the 17 novel Pandoraea species as P. anapnoica sp. nov. (type strain LMG 31117^T = CCUG 73385^T), P. anhela sp. nov. (type strain LMG 31108^T = CCUG 73386^T), P. aquatica sp. nov. (type strain LMG 31011^T = CCUG 73384^T), P. bronchicola sp. nov. (type strain LMG 20603^T = ATCC BAA-110^T), P. capi sp. nov. (type strain LMG 20602^T = ATCC BAA-109^T), P. captiosa sp. nov. (type strain LMG 31118^T = CCUG 73387^T), P. cepalis sp. nov. (type strain LMG 31106^T = CCUG 39680^T), P. commovens sp. nov. (type strain LMG 31010^T = CCUG 73378^T), P. communis sp. nov. (type strain LMG 31110^T = CCUG 73383^T), P. eparura sp. nov. (type strain LMG 31012^T = CCUG 73380^T), P. horticolens sp. nov. (type strain LMG 31112^T = CCUG 73379^T), P. iniqua sp. nov. (type strain LMG 31009^T = CCUG 73377^T), P. morbifera sp. nov. (type strain LMG 31116^T = CCUG 73389^T), P. nosoerga sp. nov. (type strain LMG 31109^T = CCUG 73390^T), P. pneumonica sp. nov. (type strain LMG 31114^T = CCUG 73388^T), P. soli sp. nov. (type strain LMG 31014^T = CCUG 73382^T), and P. terrigena sp. nov. (type strain LMG 31013^T = CCUG 73381^T).

Pandoraea sputorum Bacteremia In A Patient Who Had Undergone Allogeneic Liver Transplantation Plus Immunosuppressive Therapy: A Case Report

Pandoraea sputorum (P. sputorum), an emerging pathogen, is able to trigger a pronounced pro-inflammatory response that results in lung dysfunction in cystic fibrosis (CF) patients. All previous P. sputorum isolates have been obtained from the respiratory samples of CF patients, with no reported cases of P. sputorum bacteremia. For the first time, we report P. sputorum isolates recovered twice from the blood cultures of a patient with liver cancer who had undergone allogeneic liver transplantation. These isolates were successfully identified by combining mass spectrometry and molecular techniques based on 16S rRNA sequencing methods. At the onset of the P. sputorum bacteremia, the patient’s peripheral T, B and NK cell counts were 181.68/μL, 59.57/μL and 70.66/μL, respectively. The serum procalcitonin level, C-reactive protein level and peripheral neutrophil granulocyte percentage were 0.56 ng/mL, 61.00 mg/L and 96.8%, respectively. We found these isolates to be susceptible to ciprofloxacin and piperacillin/tazobactam and to be intermediate to amikacin. Previous studies have found P. sputorum isolates to be resistant. All of the data combined showed that compromised immune function from allogeneic liver transplantation plus immunosuppressive therapy contributes to the occurrence of P. sputorum bacteremia. Furthermore, the P. sputorum isolates demonstrated characteristic resistance profiles.

Isolation and identification of Pandoraea spp. From bronchoalveolar lavage of cystic fibrosis patients in Iran

Background

Pandoraea species are gram negative, motile, non-spore forming, rod shaped and oxidase positive, obligate aerobes bacteria, and have one polar flagellum. Most of Pandoraea species are associated with lung infections in cystic fibrosis patients. Cystic fibrosis is the most prevalent autosomal recessive hereditary disease in the world that affects various organs of the body. The main important cause of death in these patients is lung involvement. This study was conducted to isolate and identify Pandoraea bacterium from bronchoalveolar lavage and sputum samples of cystic fibrosis patients in Shiraz, Iran.

Methods

In this research 31 samples of bronchoalveolar lavage and sputum were examined by culture and PCR method. Then confirmed isolates were evaluated for susceptibility to different antibiotics and ability to produce biofilm.

Results

The results of this study after cultivation, purification and DNA extraction led to the isolation of 4 Pandoraea bacterium by PCR using specific primers. Antibiotic susceptibility test were indicated all isolates were resistant to gentamicin, amikacin and imipenem and susceptible to ciprofloxacin, trimethoprim-sulfumethoxazole, piperacillin and tetracycline. Ability to create biofilm was indicated by some of Pandoraea isolates. According to findings of this study, ability to synthesis biofilm by Pandoraea isolates and resistance to some antibiotics are very important.

Conclusions

Our study notes the role of P. pnomenusa as an emerging pathogen that can cause chronic lung colonization in CF patients. Identification tools need to be accurate and must be based on molecular techniques. Also our findings should raise awareness about antibiotic resistance in cystic fibrosis patients in Iran and ability of including bacterial agents to produce biofilm is an alarm for public health. Thus clinicians should exercise caution about finding of clinical relevance of this pathogen to the infection and prescribing antibiotics, especially in cases of children infections.