Isolates Of Lineage Research Articles

Diversification and biogeography of Rhacophoridae – a model testing approach

A central focus of evolutionary biology is to understand species diversity by studying how they arrived at their current geographic distributions. The biogeography of the Old World tree frogs in the family Rhacophoridae has been extensively studied suggesting an early Paleogene origin in Asia (out of Asia hypothesis) with alternative hypotheses in play. However, these alternative hypotheses especially considering adjacency of biogeographical regions and plate tectonics have not been tested empirically. Here using a comprehensive time calibrated phylogeny and constrained dispersal multipliers we studied the biogeographical history and diversification of Rhacophoridae, distributed in five biogeographical regions. Five hypotheses suggesting different centers of origin, and additional hypotheses considering adjacency and plate tectonics were tested to delineate the biogeographical history of Rhacophoridae. In addition, various diversification models that accounted for factors such as lineage isolation time, diversity-dependence, paleotemperatures, speciation and extinction rates were also used to test patterns of diversification. Results confirmed an East/Southeast Asian center of origin (out of Asia), with dispersal likely mediated by plate tectonics and adjacency of biogeographical regions, which could be linked to periodic sea level fluctuations and climate changes. The best-fitting diversification models explained diversification through lineage isolation time and paleotemperature regimes, while diversity-dependent models had low support. Speciation was linearly dependent on time and paleotemperatures, while extinction rates were exponentially dependent on time and linearly dependent on paleotemperature. Our findings demonstrate that variable extinction rates contribute towards maintaining a constant diversification rate for rhacophorids. We discuss that episodic major extinction events on the Indian Plate may have played a major role in shaping the early evolution of Rhacophoridae thus favoring an Out of Asia hypothesis in the empirical models. However, current biogeographic models may not be sufficient to explain the origin of Rhacophoridae, as multiple factors are likely at play.

Distinct monkeypox virus lineages co-circulating in humans before 2022

The 2022 global mpox outbreak raises questions about how this zoonotic disease established effective human-to-human transmission and its potential for further adaptation. The 2022 outbreak virus is related to an ongoing outbreak in Nigeria originally reported in 2017, but the evolutionary path linking the two remains unclear due to a lack of genomic data between 2018, when virus exportations from Nigeria were first recorded, and 2022, when the global mpox outbreak began. Here, 18 viral genomes obtained from patients across southern Nigeria in 2019–2020 reveal multiple lineages of monkeypox virus (MPXV) co-circulated in humans for several years before 2022, with progressive accumulation of mutations consistent with APOBEC3 activity over time. We identify Nigerian A.2 lineage isolates, confirming the lineage that has been multiply exported to North America independently of the 2022 outbreak originated in Nigeria, and that it has persisted by human-to-human transmission in Nigeria for more than 2 years before its latest exportation. Finally, we identify a lineage-defining APOBEC3-style mutation in all A.2 isolates that disrupts gene A46R, encoding a viral innate immune modulator. Collectively, our data demonstrate MPXV capacity for sustained diversification within humans, including mutations that may be consistent with established mechanisms of poxvirus adaptation.

The Influence of Macroclimatic Drivers on the Macrophyte Phylogenetic Diversity in South African Estuaries

The geographical distribution of plants is influenced by macroclimate and dispersal limitations, which have led to lineage isolation and subsequent diversification within and across various environmental gradients. Macroclimatic variables in coastal wetlands influence plant species and lineages across biogeographical boundaries. This study aimed to determine the influence of macroclimatic variables on species and phylogenetic richness in South African estuaries. Open-source chloroplast DNA barcoding sequences, species distribution and climatic data layers were used to determine the relationship between species richness, MPD, MNTD and each bioclimatic variable individually. Temperate species richness and phylogenetic diversity were positively correlated with temperature bioclimatic variables whereas subtropical and tropical species were associated with increases in precipitation. Phylogenetic niche conservatism is evident in malvids and rosids which are restricted to tropical and subtropical regions due to their physiological adaptations to tropical climates. Caryophylales was mostly associated with temperate regions. Poales and Alismatales showed wide distributions that is likely attributed to traits related to wind pollination and hydrochory, rapid, clonal, and high reproductive output, tolerance to stressful conditions, and intraspecific genetic diversity. The findings highlight the importance of considering macroclimate and phylogenetic factors in understanding the distribution and diversity of coastal wetland plants.

Combining RADseq and contact zone analysis to decipher cryptic diversification in reptiles: Insights from the Spiny‐footed Lizard (Reptilia, Lacertidae)

AbstractUncertainties on species taxonomy and distribution are major factors hampering efficient conservation planning in the current context of biodiversity erosion, even concerning widespread and abundant species in relatively well‐studied regions. Species delimitation have long been based on phylogenetic analyses of a small number of standard markers, but accurate lineage identification through this approach can be hampered by incomplete lineage sorting, introgression or isolation by distance. In that context, analyses of introgression patterns at secondary contact zones offer an interesting alternative by allowing a direct estimation of reproductive isolation, especially when using genome‐wide markers. Here, we investigated a contact zone between two genetic groups of the Spiny‐footed Lizard Acanthodactylus erythrurus (Schinz, 1833) in Morocco, whose status as separate lineages remained disputed in previous multilocus studies. Based on thousands of genome‐wide markers obtained through a RADseq approach, we confirmed that they represent distinct evolutionary lineages. Furthermore, the transition at their contact zone was very steep, with spatially restricted gene flow, highlighting levels of reproductive isolation consistent with species‐level lineages. Our study further illustrates the power of RADseq‐based studies of contact zones to understand cryptic diversity in non‐model organisms.

Vero CCL-81 and Calu-3 Cell Lines as Alternative Hosts for Isolation and Propagation of SARS-CoV-2 Isolated in Malaysia.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been identified as the etiologic agent for the pneumonia outbreak that started in early December 2019 in Wuhan City, Hubei Province, China. To date, coronavirus disease (COVID-19) has caused almost 6 million deaths worldwide. The ability to propagate the virus into a customizable volume will enable better research on COVID-19 therapy, vaccine development, and many others. In the search for the most efficient replication host, we inoculated three (3) local SARS-CoV-2 isolates of different lineages (Clade L/Lineage B Wuhan, Clade GR/Lineage B.1.1.354, and Clade O/Lineage B.6.2) into various clinically important mammalian cell lines. The replication profile of these isolates was evaluated based on the formation of cytopathic effects (CPE), viral load (Ct value and plaque-forming unit (pfu)), as well as observation by electron microscopy (EM). Next-generation sequencing (NGS) was performed to examine the genomic stability of the propagated SARS-CoV-2 in these cell lines. Our study found that Vero E6 and Vero CCL-81 cell lines posed similar capacities in propagating the local isolates, with Vero CCL-81 demonstrating exceptional potency in conserving the genomic stability of the Lineage B Wuhan isolate. In addition, our study demonstrated the utility of Calu-3 cells as a replication host for SARS-CoV-2 without causing substantial cellular senescence. In conclusion, this study provides crucial information on the growth profile of Malaysian SARS-CoV-2 in various mammalian cell lines and thus will be a great source of reference for better isolation and propagation of the SARS-CoV-2 virus isolated in Malaysia.

Substituting Allose as the Primary Carbon Source During Enrichment Helps Improve Detection and Isolation of Lineage II Listeria monocytogenes From Food

Testing of foods for low levels of the human pathogen, Listeria monocytogenes (Lm), involves a selective enrichment procedure. A nonpathogenic species of Listeria, L. innocua (Li), is often present in foods and food-manufacturing environments and is an interference organism for Lm detection due to competition during enrichment. The present study investigated whether a novel enrichment strategy incorporating the sugar allose into the secondary enrichment broth (allose method) could improve the detection of Lm from foods when Li is present. First, Canadian food isolates of Listeria spp. were tested to confirm recent reports that lineage II Lm (LII-Lm), but not Li, could metabolize allose. All LII-Lm isolates (n = 81), but not Li (n = 36), possessed the allose genes lmo0734-lmo0739, and could efficiently metabolize allose. Next, smoked salmon was contaminated with mixtures of LII-Lm and Li and tested using different enrichment procedures to compare the ability to recover Lm. Allose broth was more effective than Fraser Broth, with Lm detected in 87% (74 of 85) compared to 59% (50 of 85) of the samples (P < 0.05), following a common preenrichment. When evaluated against a current Health Canada method (MFLP-28), the allose method was more effective, with LII-Lm detected in 88% (57 of 65) compared to 69% (45 of 65) of the samples (P < 0.05). The allose method also remarkably increased the ratio of LII-Lm to Li postenrichment, which improved the ease of obtaining isolated Lm colonies for confirmation tests. Allose may therefore provide a tool for use when the presence of background flora interferes with Lm detection. As this tool is specifically applicable to a subset of Lm, the use of this method modification may provide a working example of tailoring methodology to target the known subtype of the pathogen of interest in an outbreak investigation, or for regular monitoring activities in conjunction with a PCR screen for allose genes on preenrichment cultures.

First Report of Fusarium oxysporum f. sp. vasinfectum causing Fusarium Wilt of Cotton in Kansas, U.S.A.

Fusarium wilt is one of the most devastating diseases of cotton (Gossypium spp.). It is caused by the soil-borne pathogen Fusarium oxysporum Schlechtend. f. sp. vasinfectum (Atk.) Snyd. & Hans (Atkinson, 1892). To date, eight races of F. oxysporum f. sp. vasinfectum have been reported worldwide based on their diverse genetics and reactions to the host (Cianchetta, et al. 2015). Fusarium wilt symptoms appear at all developing stages. The fungus enters through the roots and colonizes the vascular system, leading to discoloration and wilting (Davis et al. 2006). During a survey in the July 2021 growing season, cotton plants showing typical wilting symptoms, stem discoloration, and root rot (Fig. 1A and B) were observed in two cotton fields in Sumner County, Kansas. In order to confirm the causal agent, root tissues and lower parts of the stems were collected from 25 diseased cotton plants and cleaned as previously described by Larren et al, (2001). Small segments (1-2 cm) of roots and stems were incubated on potato dextrose agar (PDA) at room temperature. The isolates were purified with the single spore method and 23 of 25 isolates (92%) showed typical morphology of F. oxysporum, with a white-peach pigmentation as reported previously (Leslie and Summerell 2008). Two isolates, CK13B and CK18A, one from each of the two fields were selected, and genomic DNA was extracted with E.Z.N.A Fungal DNA Mini kit (Omega Bio-tek, Norcross, GA). Polymerase chain reaction (PCR) assays were performed as reported previously (Ortiz, et al. 2017) to amplify and sequence a portion of three nuclear genes: translation elongation factor (EF-1α), phosphate: H* symporter (PHO), and β-tubulin (BT). BLASTn analysis of CK13B sequences showed 93-98% identity with F. oxysporum f. sp. vasinfectum isolates originating from Australia, with 93.43% (1706/1826 pb) identity of EF-1α to isolate AuSeed14 (KT323873), 95.11% (1849/1944 bp) of PHO to isolate AuK24232 (KT323909), and 97.56% (1840/1886 bp) identity of BT to isolate AusSeed14 (KT323833). Sequences of CK13B for EF1-α, PHO, and BT genes were submitted to GenBank, accession no. of ON754247, ON754248, and ON754249, respectively. The CK18A isolate showed high identity with F. oxysporum f. sp. vasinfectum races 1, 2, and 6 lineage isolates (Ortiz et al., 2017), with 99.89% (1822/1824 bp) identity of the EF1-α gene to isolate CDR238 (KT323838) from Arkansas, 98.36% (1916/1948 bp) identity of the PHO gene to isolate CDR1131 (KT323887) from Louisiana and 98.78% (1864/1887 bp) identity of the BT gene to isolate ATCC36198 (KT323799) from Brazil. Sequences of the CK18A isolate were submitted to GenBank, accession no. ON651444, ON725043, and ON725044, respectively. Pathogenicity of both isolates was tested on G. hirsutum as previously described (Kim et al. 2005) with three replicates per isolate and a control treatment in a growth chamber. Briefly, cotton seedlings were maintained with 12 h light/dark cycle at 25-20 °C. At the first true leaf stage seedlings were uprooted, roots were cleaned by rinsing with sterile water then placed in a conidial suspension (1×106 conidia/ml) for 2 h while the healthy control seedlings were dipped in water only. Plants were put into sterile soil, and the results were observed and recorded every seven days for a period of 30 days. The inoculated plants showed the same symptoms as those observed in the fields, wilting, leaf chlorosis, and necrosis. Both isolates were re-isolated from the roots of the inoculated plants. DNA was extracted and used for PCR with the specific gene primers as listed above. The sequences matched those of the original isolates, completing the Koch's pustulates. To our knowledge, this is the first report of F. oxysporum f. sp. vasinfectum causing Fusarium wilt disease of cotton in Kansas. These results will help growers select cultivars and design disease control strategies accordingly (Davis, et al., 2006). Further work is needed to determine the specific races in the area.

Revealing the Stygobiotic and Crenobiotic Molluscan Diversity in the Caucasus: Part IV—Crenobiotic Belgrandiellinae Radoman, 1983 (Mollusca, Hydrobiidae) from Georgia

Since 2020, the south-western Caucasus has been recognized as a hotspot of stygobiotic Mollusca diversity after revealing a large number of new, range-restricted species within the spring snail family Hydrobiidae, subfamily Sadlerianinae sensu Szarowska. Meantime, based on extensive material collected in the south-western Caucasus during the last decades, we studied members of another spring snail subfamily Belgrandiellinae Radoman, 1983. Modern integrative taxonomic work revealed hitherto unknown diversity within this subfamily in the region and further proved the importance of the south-western Caucasus as a hotspot of stygobiotic life. In particular, the subterranean environment and springs of Georgia were known to be inhabited by the genus Tschernomorica Vinarski and Palatov, 2019 with four nominal species. Our research, based on a morpho-anatomical study and genetic investigation of COI/H3 mitochondrial/nuclear markers, revealed additionally seven species and three genera new to science—Colchiella lugella gen. et sp. nov., C. nazodelavo gen. et sp. nov., C. shiksa gen. et sp. nov., C. dadiani gen. et sp. nov., Sataplia cavernicola gen. et sp. nov., Aetis starobogatovi gen. et sp. nov., and Tschernomorica kopidophora sp. nov. —to inhabit the Georgian part of south-western Caucasus. The full taxonomic description of each new taxa, along with the review of habitat characteristics and conservation status, is provided. Molecular genetics suggests that the ancestors of Caucasian Belgrandiellinae have migrated from south-western Europe, probably more than once during the late Messinian and early Pliocene periods. Later, Plio-Pleistocene climate oscillations, particularly the repeated rise and fall of the Black Sea water level, resulted in the isolation and radiation of various lineages within the Caucasus and Crimea.

Structural genome variants of Pseudomonas aeruginosa clone C and PA14 strains.

Plasticity of Pseudomonas aeruginosa chromosomes is mainly driven by an extended accessory genome that is shaped by insertion and deletion events. Further modification of the genome composition can be induced by chromosomal inversion events which lead to relocation of genes in the affected genomic DNA segments, modify the otherwise highly conserved core genome synteny and could even alter the location of the replication terminus. Although the genome of the first sequenced strain, PAO1, displayed such a large genomic inversion, knowledge on such recombination events in the P. aeruginosa population is limited. Several large inversions had been discovered in the late 1990s in cystic fibrosis isolates of the major clonal lineage C by physical genome mapping, and subsequent work on these examples led to the characterization of the DNA at the recombination breakpoints and a presumed recombination mechanism. Since then, the topic was barely addressed in spite of the compilation of thousands of P. aeruginosa genome sequences that are deposited in databases. Due to the use of second-generation sequencing, genome contig assembly had usually followed synteny blueprints provided by the existing reference genome sequences. Inversion detection was not feasible by these approaches, as the respective read lengths did not allow reliable resolution of sequence repeats that are typically found at the borders of inverted segments. In this study, we applied PacBio and MinION long-read sequencing to isolates of the mentioned clone C collection. Confirmation of inversions predicted from the physical mapping data demonstrated that unbiased sequence assembly of such read datasets allows the detection of genomic inversions and the resolution of the recombination breakpoint regions. Additional long-read sequencing of representatives of the other major clonal lineage, PA14, revealed large inversions in several isolates, from cystic fibrosis origin as well as from other sources. These findings indicated that inversion events are not restricted to strains from chronic infection background, but could be widespread in the P. aeruginosa population and contribute to genome plasticity. Moreover, the monitored examples emphasized the role of small mobile DNA units, such as IS elements or transposons, and accessory DNA elements in the inversion-related recombination processes.

Nanopore-only assemblies for genomic surveillance of the global priority drug-resistant pathogen, Klebsiella pneumoniae.

Oxford Nanopore Technologies (ONT) sequencing has rich potential for genomic epidemiology and public health investigations of bacterial pathogens, particularly in low-resource settings and at the point of care, due to its portability and affordability. However, low base-call accuracy has limited the reliability of ONT data for critical tasks such as antimicrobial resistance (AMR) and virulence gene detection and typing, serotype prediction, and cluster identification. Thus, Illumina sequencing remains the standard for genomic surveillance despite higher capital and running costs. We tested the accuracy of ONT-only assemblies for common applied bacterial genomics tasks (genotyping and cluster detection, implemented via Kleborate, Kaptive and Pathogenwatch), using data from 54 unique Klebsiella pneumoniae isolates. ONT reads generated via MinION with R9.4.1 flowcells were basecalled using three alternative models [Fast, High-accuracy (HAC) and Super-accuracy (SUP), available within ONT's Guppy software], assembled with Flye and polished using Medaka. Accuracy of typing using ONT-only assemblies was compared with that of Illumina-only and hybrid ONT+Illumina assemblies, constructed from the same isolates as reference standards. The most resource-intensive ONT-assembly approach (SUP basecalling, with or without Medaka polishing) performed best, yielding reliable capsule (K) type calls for all strains (100 % exact or best matching locus), reliable multi-locus sequence type (MLST) assignment (98.3 % exact match or single-locus variants), and good detection of acquired AMR genes and mutations (88-100 % correct identification across the various drug classes). Distance-based trees generated from SUP+Medaka assemblies accurately reflected overall genetic relationships between isolates. The definition of outbreak clusters from ONT-only assemblies was problematic due to inflation of SNP counts by high base-call errors. However, ONT data could be reliably used to 'rule out' isolates of distinct lineages from suspected transmission clusters. HAC basecalling + Medaka polishing performed similarly to SUP basecalling without polishing. Therefore, we recommend investing compute resources into basecalling (SUP model), wherever compute resources and time allow, and note that polishing is also worthwhile for improved performance. Overall, our results show that MLST, K type and AMR determinants can be reliably identified with ONT-only R9.4.1 flowcell data. However, cluster detection remains challenging with this technology.

Comparative analysis of Methicillin-resistant Staphylococcus aureus through whole genome sequencing in the largest tertiary care hospital in Peshawar, Pakistan.

Methicillin-resistant Staphylococcus aureus (MRSA) is a globally disseminated antibiotic-resistant pathogen and causes mild to severe infections. The population structure of MRSA is highly clonal and individual genetic clones harbor specific plasmid, and determinants for antibiotic resistance and virulence, therefore, whole genome sequencing (WGS) of five MRSA isolates of the predominant genetic lineage was performed to gain insight into the most prevalent endemic strains. Sequencing libraries were arranged in accordance with the Nextera XT DNA Library Prep Guide (Illumina). WGS was performed on Illumina NextSeq 500 platform with 2×151bp using a NextSeq Mid-Output Kit. The sequenced genome was characterized for spa type, MLST type, SCCmec type, plasmid, antibiotic resistance gene, and virulence gene by publicly available bioinformatics tools on the website of the Center for Genomic Epidemiology. All the isolates were characterized as ST8/t064-SCCmecIVa(2B) clones of MRSA and, A total of 13 resistance genes, 11 virulence genes, and 6 types of plasmids were identified in the sequenced isolates of MRSA, furthermore, the sequenced isolates showed a similar pattern of distribution for antibiotic resistance genes and virulence genes. WGS revealed that the isolates are genetically closely related and showed a similar pattern of distribution for different genetic markers, therefore, these strains could be an accidental case cluster or cluster of an outbreak.

Palynology of Amicia Kunth. (Leguminosae – Papilionoideae – Dalbergieae – Informal Adesmia clade) set in a systematic and phylogenetic context

Amicia is the least diverse genus of the Adesmia clade. It has a disjunct distribution with six endemic species restricted to the central Andes of South America and one species endemic to Mexico. The phylogeny and taxonomy of this genus have been extensively studied. Nevertheless, pollen data are still insufficiently known within a taxonomic context. In this study, we analysed all Amicia species using light, scanning, and transmission electron microscopy and we present phylogenetically useful palynological information to support taxonomic studies. Variation in pollen grain size and aperture features is used to delimit pollen types, which corroborate molecular and biogeographical data. Multivariate analysis reinforced the pollen type subdivisions and revealed novel diagnostic morphological features for two infrageneric taxa of Amicia. Our pollen results provide informative pollen characters to assist in the delimitation of Amicia species, which can be easily misidentified due to similarities in vegetative structures. Amicia pollen morphology reflects population isolation and divergence of Amicia lineages and provides critical features for future phylogenetic optimisation of the Adesmia clade.

Characterization of SARS-CoV-2 Omicron BA.4 and BA.5 isolates in rodents.

The BA.2 sublineage of the SARS-CoV-2 Omicron variant has become dominant in most countries around the world; however, the prevalence of BA.4 and BA.5 is increasing rapidly in several regions. BA.2 is less pathogenic in animal models than previously circulating variants of concern1-4. Compared with BA.2, however, BA.4 and BA.5 possess additional substitutions in the spike protein, which playa key role in viral entry, raising concerns that the replication capacity and pathogenicity of BA.4 and BA.5 are higher than those of BA.2. Here we have evaluated the replicative ability and pathogenicity of BA.4 and BA.5 isolates in wild-type Syrian hamsters, human ACE2 (hACE2) transgenic hamsters and hACE2 transgenic mice. We have observed no obvious differences among BA.2, BA.4 and BA.5 isolates in growth ability or pathogenicity in rodent models, and less pathogenicity compared to a previously circulating Delta (B.1.617.2 lineage) isolate. In addition, in vivo competition experiments revealed that BA.5 outcompeted BA.2 in hamsters, whereas BA.4 and BA.2 exhibited similar fitness. These findings suggest that BA.4 and BA.5 clinical isolates have similar pathogenicity to BA.2 in rodents and that BA.5 possesses viral fitness superior to that of BA.2.

Hypervirulent Clostridioides difficile RT078 lineage isolates from the river: A potential reservoir for environmental transmission.

This is the first report to discover Clostridiodes difficile (C. difficile) ribotype RT126 and RT598 (both ribotypes belong to RT078-lineage) in a river water system in southern Taiwan. Fluoroquinolone resistance was also found. The connection between clinical isolates and those from the environment needs further investigation.

Genetic Divergence of Vibrio vulnificus Clinical Isolates with Mild to Severe Outcomes.

ABSTRACTThe marine bacterium Vibrio vulnificus infects humans via food or water contamination, leading to serious manifestations, including gastroenteritis, wound infections, and septic shock. Previous studies suggest phylogenetic Lineage 1 isolates with the vcgC allele of the vcg gene cause human infections, whereas Lineage 2 isolates with the vcgE allele are less pathogenic. Mouse studies suggest that some variants of the primary toxin could drive more serious infections. A collection of 109 V. vulnificus United States human clinical isolates from 2001 to 2019 with paired clinical outcome data were assembled. The isolates underwent whole-genome sequencing, multilocus-sequence phylogenetic analysis, and toxinotype analysis of the multifunctional autoprocessing repeats-in-toxin (MARTX) toxin. In contrast to prior reports, clinical isolates were equally distributed between lineages. We found no correlation between phylogenetic lineage or MARTX toxinotype and disease severity. Infections caused by isolates in Lineage 1 demonstrated a borderline statistically significant higher mortality. Lineage 1 isolates had a trend toward a higher proportion of M-type MARTX toxins compared with Lineage 2, although this was not statistically significant.

Molecular characterization and sequecing analysis of SARS-CoV-2 genome in Minas Gerais, Brazil

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), first identified in Wuhan, China, is the causative agent of the coronavirus disease 2019 (COVID-19). Since its first notification in São Paulo state (SP) on 26th February 2020, more than 22,300,000 cases and 619,000 deaths were reported in Brazil. In early pandemic, SARS-CoV-2 spread locally, however, over time, this virus was disseminated to other regions of the country. Herein, we performed genomic sequencing and phylogenetic analysis of SARS-CoV-2 using 20 clinical samples of COVID-19 confirmed cases from 9 cities of Minas Gerais state (MG), in order to evaluate the molecular properties of circulating viral strains in this locality from March to May 2020. Our analyses demonstrated the circulation of B.1 lineage isolates in the investigated locations and nucleotide substitutions were observed into the genomic regions related to important viral structures. Additionally, sequences generated in this study clustered with isolates from SP, suggesting a dissemination route between these two states. Alternatively, monophyletic groups of sequences from MG and other states or country were observed, indicating independent events of virus introduction. These results reinforce the need of genomic surveillance for understand the ongoing spread of emerging viral pathogens.

Diversity of thermal aptitude of Middle Eastern and Mediterranean Puccinia striiformis f. sp. tritici isolates from different altitude zones

AbstractThe worldwide spread of wheat yellow rust lineage PstS1/S2 adapted to higher temperatures prompted us to investigate how diverse temperature responses of this lineage are in the Middle East, where diversity was previously observed within this lineage for pathotypes and genotypes. Here we highlight the diversity of response to temperature within a PstS1/S2 population. Twenty‐six isolates from eight countries and different altitudes, which were tested under four combinations of cold and warm incubation and postincubation temperature conditions, showed diversity for infection efficiency (IE) and latency period (LP). IE of the various isolates ranged from 5.8% to 13.7% under cold (5°C) and 0.04% to 1% under warm (20°C) incubation temperatures. LP varied from 10.2 days under warm to 4.43 days under cold incubation. LP of isolates from the same country could differ by 2 days. Significant differences in thermal aptitudes of the isolates were observed between and within countries. IE and LP diversity was not related to altitude origin of the isolates on the whole; however, a trade‐off between IE and LP was observed for isolates from low altitude (&lt;400 m) under a warm regime. We showed diversity for thermal aptitude for IE and LP of isolates belonging to the same PstS1/S2 lineage. Understanding Pst temperature aptitude among geographically distant isolates of the same clonal lineage may help to identify the geographic range of pathogens and also to improve forecast models or breeding programmes.

Elucidating the virulence genes harboured by carbapenemase- and non-carbapenemase-producing carbapenem-resistant Klebsiella pneumoniae rectal isolates from patients admitted to intensive care units using whole-genome sequencing in Kuwait.

Introduction. Klebsiella pneumoniae is a Gram-negative pathogen responsible for community- and nosocomial-acquired infections. The presence of an accessory genome determines the bacterial pathogenicity and the host immune response, and thus indicates multidrug-resistant strains or more virulent groups. Little is known about the virulence genes in K. pneumoniae in Kuwait.Hypothesis/Gap Statement. The diversity of virulence genes and capsule loci in K. pneumoniae isolates warrants further genomic studies to better understand their transmission within the hospitals in Kuwait.Aim. We aimed to investigate the virulence genes harboured by K. pneumoniae isolated from rectal swabs of intensive care unit (ICU) patients in two Kuwaiti teaching hospitals.Methodology. Six isolates from patients in the ICUs of Al Razi and Mubarak hospitals, designated RZH144, RZH132 RZH108 and RZH173, and MKH381 and MKH347, respectively, were subjected to whole-genome sequencing (WGS) assays. RZH144 and RZH132 were non-carbapenemase-producing K. pneumoniae (NCKP) isolates negative for genes encoding carbapenemase production by PCR assays, and the remaining four were carbapenemase-producing K. pneumoniae (CPKP) isolates. Isolates were characterized by phenotypic, PCR and WGS methods. Susceptibility testing was performed by E test and clonality by multilocus sequence typing. Analysis of the isolates' assembled contigs was carried out using Kleborate (https://pathogen.watch).Results. An NCPE RZH132 K. pneumoniae isolate belonged to ST231-wzi104 and harboured gene clusters encoding the biosynthesis of the siderophore aerobactin (iuc5) on 62-3LV. The capsular locus variants were KL51 and O locus O1v2. Another NCPKP RZH144 isolate was confirmed as ST43-wzi412 and harboured KL61 and O1v1. The four CPKP isolates harboured two virulence loci - ybt14 and iuc5 - encoding the siderophores yersiniabactin and aerobactin, respectively. They belonged to ST231-wzi104 and harboured yersiniabactin on ICEKp5. The sequence type of ybt was YbST145-1LV. Strain RZ108 was devoid of virulence loci. Its sequence type was ST15-wzi151 and harboured KL48 and O1V1. ST231 clonal lineage isolates shared common virulence plasmid variants.Conclusion. The CPKP ST231 had the highest virulence score and contained iuc5, which was found for the first time in ST231-CPKP isolates in Kuwait.

A Reverse Mutation E143K within the PrM Protein of Zika Virus Asian Lineage Natal RGN Strain Increases Infectivity and Cytopathicity.

Zika virus (ZIKV) is a positive-sense single-stranded RNA virus in the Flaviviridae, which is classified into two different lineages Asian and African. The outbreak of ZIKV Asian lineage isolates in 2015–2016 is associated with the increase in cases with prenatal microcephaly and Guillain–Barré syndrome, and has sparked attention throughout the world. Genome sequence alignment and the analysis of Asian and African lineage isolates indicate that amino acid changes, particular in positively charged amino acid substitutions in the pr region of prM protein might involve a phenotypic change that links with the global outbreak of ZIKV Asian-lineage. The study generated and characterized the virological properties of wild type and mutants of single-round infectious particles (SRIPs) and infectious clones (i.c.s) of ZIKV Asian-lineage Natal RGN strain, and then identified the function of amino acid substitutions at the positions 139 [Asn139→Ser139 (N139S)] and 143 [Glu143→Lys143 (E143K)] in ZIKV polyproteins (located within the pr region of prM protein) in the infectivity and cytopathogenicity. The E143K SRIP and i.c. of Natal RGN strain exhibited relatively higher levels of cytopathic effect, EGFP reporter, viral RNA and protein synthesis, and virus yield in three types of human cell lines, TE617, SF268 and HMC3, compared to wild type (WT), N139S SRIPs and i.c.s, which displayed more efficiency in replication kinetics. Additionally, E143K Natal RGN i.c. had greater activities of virus attachment and entry, yielded higher titers of intracellular and extracellular virions, and assembled the E proteins near to the plasma membrane in infected cells than the other i.c.s. The results indicate that the positively charged amino acid residue Lys143, a conserved residue in the pr region of prM of ZIKV African lineages, plays a crucial role in viral replication kinetics, including viral attachment, entry, assembly and egress. Thus, the negatively charged amino acid residue Glu143 within the pr region of prM leads to an alteration of the phenotypes, in particular, a lower replication efficiency of ZIKV Asian-lineage isolates with the attenuation of infectivity and cytopathicity.

Multiple chikungunya virus introductions in Lao PDR from 2014 to 2020.

The first documented chikungunya virus (CHIKV) outbreak in Lao People’s Democratic Republic (Lao PDR) occurred in 2012–2013. Since then, several imported and a few autochthonous cases were identified by the national arbovirus surveillance network. The present study aimed to summarize the main genetic features of the CHIKV strains detected in Lao PDR between 2014 and 2020. Samples from Lao patients presenting symptoms compatible with a CHIKV infection were centralized in Vientiane Capital city for real-time RT-PCR screening. Molecular epidemiology was performed by sequencing the E2-6K-E1 region. From 2014 to 2020, two Asian lineage isolates (e.g. French Polynesia; Indonesia), one ECSA-IOL lineage isolate (e.g. Thailand) and one unclassified (e.g. Myanmar) were imported in Vientiane Capital city. Sequences from the autochthonous cases recorded in the Central and Southern parts of the country between July and September 2020 belonged to the ECSA-IOL lineage and clustered with CHIKV strains recently detected in neighboring countries. These results demonstrate the multiple CHIKV introductions in Lao PDR since 2014 and provide evidence for sporadic and time-limited circulation of CHIKV in the country. Even if the circulation of CHIKV seems to be geographically and temporally limited in Lao PDR, the development of international tourism and trade may cause future outbreaks of CHIKV in the country and at the regional level.