The dominant cause of malaria in Malaysia is now Plasmodium knowlesi, a zoonotic parasite of cynomolgus macaque monkeys found throughout South East Asia. Comparative genomic analysis of parasites adapted to in vitro growth in either cynomolgus or human RBCs identified a genomic deletion that includes the gene encoding normocyte-binding protein Xa (NBPXa) in parasites growing in cynomolgus RBCs but not in human RBCs. Experimental deletion of the NBPXa gene in parasites adapted to growth in human RBCs (which retain the ability to grow in cynomolgus RBCs) restricted them to cynomolgus RBCs, demonstrating that this gene is selectively required for parasite multiplication and growth in human RBCs. NBPXa-null parasites could bind to human RBCs, but invasion of these cells was severely impaired. Therefore, NBPXa is identified as a key mediator of P. knowlesi human infection and may be a target for vaccine development against this emerging pathogen.

The seafloor is a unique environment, which allows insights into how geochemical processes affect the diversity of biological life. Among its diverse ecosystems are deep-sea brine pools - water bodies characterized by a unique combination of extreme conditions. The ‘polyextremophiles’ that constitute the microbial assemblage of these deep hot brines have not been comprehensively studied. We report a comparative taxonomic analysis of the prokaryotic communities of the sediments directly below the Red Sea brine pools, namely, Atlantis II, Discovery, Chain Deep, and an adjacent brine-influenced site. Analyses of sediment samples and high-throughput pyrosequencing of PCR-amplified environmental 16S ribosomal RNA genes (16S rDNA) revealed that one sulfur (S)-rich Atlantis II and one nitrogen (N)-rich Discovery Deep section contained distinct microbial populations that differed from those found in the other sediment samples examined. Proteobacteria, Actinobacteria, Cyanobacteria, Deferribacteres, and Euryarchaeota were the most abundant bacterial and archaeal phyla in both the S- and N-rich sections. Relative abundance-based hierarchical clustering of the 16S rDNA pyrotags assigned to major taxonomic groups allowed us to categorize the archaeal and bacterial communities into three major and distinct groups; group I was unique to the S-rich Atlantis II section (ATII-1), group II was characteristic for the N-rich Discovery sample (DD-1), and group III reflected the composition of the remaining sediments. Many of the groups detected in the S-rich Atlantis II section are likely to play a dominant role in the cycling of methane and sulfur due to their phylogenetic affiliations with bacteria and archaea involved in anaerobic methane oxidation and sulfate reduction.

Background Soybean ( Glycine max ) and other legumes are key crops grown around the world, providing protein and nutrients to a growing population, in a way that is more sustainable than most other cropping systems. Diazotrophs inhabiting root nodules provide soybean with nitrogen required for growth. Despite the knowledge of culturable Bradyrhizobium spp. and how they can differ across cultivars, less is known about the overall bacterial community (bacteriome) diversity within nodules, in situ. This variability could have large functional ramifications for the long-standing scientific dogma related to the plant-bacteriome interaction. Water availability also impacts soybean, in part, as a result of water-deficit sensitive nodule diazotrophs. There is a dearth of information on the effects of cultivar and water status on in situ rhizobia and non-rhizobia populations of nodule microbiomes. Therefore, soybean nodule microbiomes, using 16S rRNA and nifH genes, were sampled from nine cultivars treated with different field water regimes. It was hypothesized that the nodule bacteriome, composition, and function among rhizobia and non-rhizobia would differ in response to cultivar and soil water status. Results 16S rRNA and nifH showed dominance by Bradyrhizobiaceae , but a large diversity was observed across phylogenetic groups with < 1% and up to 45% relative abundance in cultivars. Other groups primarily included Pseudomonadaceae and Enterobacteriaceae . Thus, nodule bacteriomes were not only dominated by rhizobia, but also described by high variability and partly dependent on cultivar and water status. Consequently, the function of the nodule bacteriomes differed, especially due to cultivar. Amino acid profiling within nodules, for example, described functional changes due to both cultivar and water status. Conclusions Overall, these results reveal previously undescribed richness and functional changes in Bradyrhizobiaceae and non-rhizobia within the soybean nodule microbiome. Though the exact role of these atypical bacteria and relative variations in Bradyrhizobium spp. is not clear, there is potential for exploitation of these novel findings of microbiome diversity and function. This diversity needs consideration as part of bacterial-inclusive breeding of soybean to improve traits, such as yield and seed quality, and environmental resilience. Electronic supplementary material The online version of this article (10.1186/s40168-019-0676-8) contains supplementary material, which is available to authorized users.

Urinary tract infections (UTIs) associated with Escherichia coli are a growing threat with an increase in the prevalence of multidrug resistant (MDR) strains, particularly ß-lactamase producers, occurring globally. We investigated the presence of carbapenem-resistant uropathogenic E. coli clones in community-acquired UTIs in Riyadh, Kingdom of Saudi Arabia (KSA) to identify the virulence and resistance structures of the resistant clones and relate the isolates to those circulating globally. A combination of comparative genomics and phenotypic approaches were used to characterize ten MDR-uropathogenic Escherichia coli isolates recovered from UTI patients in Riyadh between November 2014 and January 2015. We report the presence of NDM-1 and 5, and OXA-181 in carbapenem-resistant UPEC strains from Riyadh, KSA. Single nucleotide polymorphism analyses demonstrated that these ten isolates fell into four phylogenetically distinct clades within the UPEC phylogeny. Comparative genomic analyses indicate that these diverse clones could be distinguished according to their multilocus sequencing type (MLST), serology, and virulence and antimicrobial gene architectures. These clones include the blaNDM-1 carrying isolates of the globally predominant MDR ST131 and ST69 types, previously identified as one of the most common UPEC strains in KSA. This is in addition to clones of ST23Cplx (ST410) and ST448Cplx (ST448) that have likely evolved from common intestinal strains, carrying copies of ß-lactamase genes including blaNDM-5, blaCTX-M-15, blaTEM-1, blaCMY-42, blaOXA-1 and blaOXA-181. These data have identified an emerging public health concern and highlight the need to use comprehensive approaches to detect the structure of MDR E. coli populations associated with community-acquired UTIs in KSA.

We assessed the presentation and mechanisms of blunt chest injuries sustained in different age groups, and the impact on management options. We retrospectively reviewed the records of 486 patients with blunt chest trauma who were treated between 2004 and 2007. They were stratified into 3 age groups: pediatric, adult, and elderly. Clinical data, mechanism of injury, associated injuries, treatment strategies, and mortality were analyzed. The majority of patients were male (86%), and the largest age group was 12-60-years old (79%). Motor vehicle accidents accounted for 93% of cases. Isolated chest injuries were more common than combined injuries (69% vs. 31%). Tube thoracostomy was required in 39% of patients, predominantly in the elderly age group. Combined injuries involved bone fractures (21%), head (5%), and abdominal trauma (5%). Most blunt chest injuries were treated conservatively (95.5%). Open thoracotomy was required in 4.5% for clotted hemothorax (3.7%), empyema (0.6%), and massive air leak (0.2%). Mortality was 1%, predominantly in the adult group (0.8%). Blunt thoracic injuries are a major cause of morbidity and mortality. As the majority of such injuries are related to motor vehicle accidents, preventative strategies should be enforced.