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Access Microbiology

Microbiology Society

Preprints posted in the last 30 days, ranked by how well they match Access Microbiology's content profile, based on 25 papers previously published here. The average preprint has a 0.03% match score for this journal, so anything above that is already an above-average fit.

1
Oligella otitidis sp. nov., isolated from middle ear discharge of children with chronic suppurative otitis media

Beissbarth, J.; Atto, B.; Mandal, P. K.; Cleanthous, A.; Harrison, B.; Gill, N. J.; Smith-Vaughan, H. C.; Kleinecke, M.; Rigas, V.; Leach, A. J.; Morris, P. S.; Marsh, R. L.

2026-06-30 microbiology 10.64898/2026.06.29.735399 medRxiv
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Oligella otitidis MSHR-50489EDL strain (ATCC: TSD462; DSMZ: DSM118617) is a new species of the genus Oligella that was isolated from a middle ear discharge swab from a child with chronic suppurative otitis media (CSOM). This Gram-negative coccobacillus produces small, circular, smooth, whitish-opaque and occasionally mucoid colonies. It grows in aerobic conditions at a temperature range from 25-42oC. Phylogenetic analysis demonstrates a relationship to other species of the genera Oligella and average nucleotide identity and digital DNA/DNA hybridization values indicate a distinct species in comparison to other Oligella species. Thus far, the majority of isolates exhibit resistance to ciprofloxacin, the first line treatment for CSOM.

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Inter-population connectivity of southern elephant seals and the likely intra-species transmission pathways of high pathogenicity avian influenza

McMahon, C.; Hindell, M.; Harcourt, R.; Lerpiniere, I.; Jonsen, I.; Guinet, C.; Woods, R.; Bester, M.; Younger, J. L.; Fountain Jones, N. M.; Burgess, T.

2026-07-08 ecology 10.64898/2026.07.07.737127 medRxiv
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High Pathogenicity Avian Influenza (HPAI) H5N1 clade 2.3.4.4b has spread beyond birds to affect seals across the Southern Ocean and sub-Antarctic region, with southern elephant seals (Mirounga leonina) particularly devastated. The virus, likely introduced via spillover from infected migratory birds, has killed tens of thousands of adult seals and pups throughout most of their range, though Macquarie Island remains unaffected so far. We used twenty years of elephant seal movement data from the southern Indian and Pacific oceans to assess whether seal-to-seal transmission could spread HPAI H5N1 between breeding colonies, despite the vast distances separating them (Marion Island, Iles Crozet, Iles Kerguelen, and Macquarie Island). There was substantial overlap in seals' at-sea distributions during their winter post-moult trips, when seals travel for weeks at average speeds of 3.5 km/h. Two transmission pathways were examined: (1) terrestrial "stepping stone" routes, where infected seals could pass the virus between colonies during short intervals to remain infectious were feasible from Marion Island to Kerguelen but not from Kerguelen to Macquarie Island; and (2) at-sea encounters between seals, which occurred frequently enough to enable transmission. The findings suggest that once established at Macquarie Island, the virus could potentially spread further to New Zealand's sub-Antarctic islands and mainland New Zealand. While seal-to-seal transmission appears possible, we conclude this is unlikely. Nonetheless, understanding at-sea contact rates enhances knowledge of H5N1 epidemiology and demonstrates the value of combining long-term population monitoring with movement data to understand wildlife disease dynamics.

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Environmental Drivers and Distribution of Pathogenic Vibrio Species in the Teign Estuary, UK

Boote, H.; Coyle, N. M.; Forde, A.; Alexa, I.; Burchell, M.; Reynolds, S.; Studholme, D. J.; Wagley, S.

2026-07-01 microbiology 10.64898/2026.06.30.735665 medRxiv
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Climate-driven increases in sea surface temperature have been associated with the expansion of Vibrio species and a corresponding rise in vibriosis cases in both human populations and aquaculture systems. Coastal waters across the south of England are increasingly becoming suitable for the growth and establishment of both human- and aquaculture-associated Vibrio species, potentially increasing vulnerability to the types of infections and disease outbreaks already reported elsewhere in the world. In this study, we report the presence of a diverse and well-established Vibrio community within the Teign Estuary, (Southwest, UK), including the human-pathogenic species V. parahaemolyticus, V. cholerae (non-O1/non-O139), V. alginolyticus, and V. diabolicus, as well as the important aquaculture pathogens V. jasicida, V. aestuarianus, and V. anguillarum. We identified V. diabolicus, a species that was indistinguishable from V. alginolyticus using conventional biochemical identification methods and could only be accurately resolved by whole-genome sequencing and developed novel PCR targets to differentiate these species in the lab. Using the insect infection model Galleria mellonella, we demonstrate that environmental isolates of V. cholerae (non-O1/non-O139), V. parahaemolyticus, and V. alginolyticus possess virulence potential. We also investigated the effects of sewage effluent on the growth of Vibrio isolates from the Teign Estuary and found that sewage can preferentially promote the growth of Vibrio species. Furthermore, several Vibrio isolates were multidrug resistant and carried antimicrobial resistance genes, highlighting the potential role of environmental Vibrio populations in the Teign Estuary as reservoirs of antimicrobial resistance. Together, these findings demonstrate how rising sea surface temperatures and sewage pollution may influence the emergence, persistence, and public health and aquaculture significance of Vibrio species in UK coastal waters.

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Comparative analyses of Gram-negative bacteria isolated from cancer patients with bacteraemia at the Uganda Cancer Institute

Lubwama, M.; Hoyles, L.; McCartney, A. L.; Kateete, D. P.; Bwanga, F.; Kigozi, E.; Kalema, L.; Asiimwe, B.; Katende, G.; Lwigale, F.; Sekyanzi, S.; Niyonzima, N.; Orem, J.; Ddungu, H.; Kambugu, J.; Phipps, W.; Winter, J.

2026-07-06 microbiology 10.64898/2026.07.05.736378 medRxiv
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Antimicrobial resistance (AMR) exacerbates bacteraemia in cancer patients, particularly in low-resource settings. At the Uganda Cancer Institute, high rates of Enterobacterales producing extended-spectrum {beta}-lactamases (ESBLs) have been reported, with DNA-based detection of bla genes limited to PCR. This study aimed to determine whether bacterial genomic DNA shipped at ambient temperature from Uganda to the UK retained sufficient quality for whole-genome sequencing (WGS), to allow in-depth genomic analyses of isolates. Genomic DNA was extracted from Gram-negative bloodstream isolates (n=77) in Uganda and shipped to the UK at ambient temperature. rpoB gene (77/77, 100%) and WGS data (72/77, 93.5%) were generated for isolates, with 66/72 (91.7%) genomes of high-quality (Escherichia coli n=34; Klebsiella spp. n=32). Bioinformatic analyses included species identification, sequence typing, SNP analysis, AMR and virulence gene profiling, and comparison with publicly available genomes of Ugandan isolates. Phenotypic-genotypic concordance was generally high: 7/77 (9.1%) isolates were misidentified by phenotypic testing, and two showed unexplained carbapenem resistance. E. coli isolates showed diverse sequence types, with high prevalence of blaCTX-M (91.2%) and blaOXA-1 (47.1%); carbapenemase genes were rare. Klebsiella isolates lacked hypermucoidy loci and displayed diverse capsule types, with a high prevalence of ESBLs. Genomic clustering suggested limited within-hospital transmission of strains. Genomic data can provide important insights into the dissemination of bacterial subclades of global concern. The widespread AMR genotypes reported here highlight the need for improved diagnostics and updated treatment guidelines for bacteraemia in Ugandan cancer patients.

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Long read and short read whole genome sequencing are equivalent for genomic characterisation of bacteriophage: considerations for high throughput analysis

Carr, P. G.; Iszatt, J. J.; Hedges, M. G.; Mantjani, L.; Vaitekenas, A.; Stick, S. M.; Kicic, A.; Montgomery, S. T.; Phage WA,

2026-07-09 microbiology 10.64898/2026.07.08.737226 medRxiv
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Background: Antimicrobial resistance (AMR) is a global health crisis, necessitating alternative antibacterial strategies. Bacteriophages (phages) offer a promising solution, and their use as a therapeutic agent relies on stringent bioinformatic characterisation using whole genome sequencing (WGS) technologies. However, phages are highly diverse, with no clear consensus on best practices concerning phage DNA extraction or sequencing platform. Efficient and repeatable DNA extraction, sequencing, and bioinformatics processes are critical for safety assessments but remain poorly defined. Additionally, the impact of sequencing platform choice and DNA extraction methods on downstream genomic analyses is not well understood. Methods: We evaluated multiple DNA extraction, library preparation, and sequencing approaches using a diverse collection of Pseudomonas phages from the PhageWA biobank. Column-based and precipitation-based DNA extraction methods were compared for DNA yield and recovery efficiency. Genome sequencing was performed using short-read (Illumina) and long-read (Oxford Nanopore Technologies) platforms, incorporating multiple library preparation kits and Nanopore basecalling models. Assemblies were assessed for completeness, quality, and sequence concordance using standardised bioinformatics pipelines, with hybrid Illumina-Nanopore assemblies used as references for comparison. Results: DNA extraction efficiency varied substantially between protocols, with the Puregene precipitation-based method yielding significantly higher DNA recovery than column-based approaches when normalised to phage titre. Illumina sequencing consistently generated complete genome assemblies, although assembly fragmentation was observed for several jumbo phages when using the SeqWell ExpressPlex 2.0 library preparation method. For Nanopore sequencing, ligation-based native barcoding libraries produced longer reads than rapid barcoding libraries, while selection of the Dorado v5.0.0 basecalling model significantly improved read quality. Genome assembly success was dependent on phage genus; native Nanopore sequencing failed to assemble several Pbunavirus genomes, likely due to modified DNA bases, but an amplification-based library preparation successfully resolved these genomes. Across successfully assembled samples, Illumina and Nanopore platforms produced highly concordant genomes with comparable completeness scores, and hybrid polishing identified only minor sequence differences. Conclusions: DNA extraction methodology, sequencing chemistry, and basecalling model selection significantly influence phage WGS outcomes. Precipitation-based DNA extraction improved DNA recovery, while both Illumina and Nanopore sequencing generated high-quality phage genomes suitable for therapeutic characterisation. Nanopore sequencing provided assemblies comparable to Illumina with minimal benefit from hybrid polishing, supporting its routine use for phage genomics. These findings provide practical guidance for phage genome characterisation workflows and contribute to the development of standardised, regulatory-grade approaches for therapeutic phage assessment.

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Gram-negative-dominated polymicrobial microbiome of necrotizing soft tissue infections from North India: an integrated culture and 16S rRNA metagenomics prospective cohort study

Vashist, T.; Rana, N.; Nair, D.; Sharma, V.; Anil, A.; Tandup, C.; Ray, P.; Angrup, A.

2026-06-27 microbiology 10.64898/2026.06.25.734553 medRxiv
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Necrotizing soft tissue infections (NSTIs) carry 10 to 30% mortality. Current empirical antimicrobial guidance derives almost entirely from Western cohorts dominated by Streptococcus pyogenes and aerobic-anaerobic consortia, yet whether this microbial paradigm applies to tropical, high-antimicrobial-pressure settings has not been tested with culture-independent methods. We did a prospective cohort study of 169 patients with intraoperatively confirmed NSTI at a North Indian tertiary center (2021 to 2024). Wound tissue underwent aerobic and anaerobic culture, QIIME2-based 16S rRNA gene amplicon sequencing (V3-V4), and targeted SYBR Green quantitative PCR (qPCR) for Acinetobacter baumannii and S. pyogenes. The wound microbiota was overwhelmingly Gram-negative and polymicrobial, anchored by A. baumannii (culture, 33.7%; metagenomics, 49.1%; qPCR, 37.9%), Escherichia coli (32.0%), and Klebsiella pneumoniae (20.7%); S. pyogenes contributed only 4.7% of culture-positive cases. Polymicrobial wounds had higher Shannon diversity (2.59 versus 2.33; P = 0.048) and discrete community composition (PERMANOVA R2 = 0.511; P = 0.010). Culture-metagenomics agreement ranged from almost perfect for Escherichia ({kappa} = 0.849) to slight for Streptococcus ({kappa} = 0.131). North Indian NSTIs present a microbial picture distinct from the Western paradigm, with implications for empirical therapy.

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Landscape of non-SARS-CoV-2 respiratory virus sequence data in Africa

Kwok, K.; Mojsiejczuk, L.; Hughes, J.; da Silva Filipe, A.; Ho, A.

2026-07-01 infectious diseases 10.64898/2026.06.27.26356737 medRxiv
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Background Sequencing capacity in Africa greatly expanded during the COVID-19 pandemic. However, the availability of sequence data for non-SARS-CoV-2 respiratory viruses in the region remains uncertain. We systematically analysed sequence data from GenBank, GISAID and Pathoplexus for 12 non-SARS-CoV-2 respiratory virus groups from Africa and compared Africa's genomic record availability with global genomic datasets. We further examined global genomic sequences to identify virus-specific patterns that could inform respiratory virus monitoring efforts in Africa. Results In Africa, the most sequenced virus was respiratory syncytial virus (RSV) (n=15,452), followed by influenza A virus (IAV) (n=10,900) and rhinovirus (n=4,774), when all sequences, including partial ones, were considered. Kenya and South Africa together contributed more than 60% of African respiratory virus sequences, while 30% of African countries submitted none. Within the global dataset of near-complete genomes, IAV was the most sequenced virus in Africa, consistent with global trends. However, Africa contributed the second-lowest number of genomes per million population among all world regions, exceeding only Asia. Substantial differences in relative genetic diversity were observed across viruses. Cytomegalovirus (94%) and parechovirus (38%) showed high sequence retention after clustering, with their clusters typically comprising sequences from a single region. In contrast, influenza viruses and RSV exhibited lower retention, with most clusters circulating across world regions. Additionally, sequences generated through next-generation sequencing were generally more complete than those obtained using Sanger sequencing. Conclusions Our analysis revealed substantial regional disparities in respiratory virus sequence availability across Africa, along with differences in diversity and geographical distribution patterns observed among viruses. This indicates the need for tailored and virus-specific surveillance strategies. Expanding sequencing capacity in more African nations is crucial for a clearer understanding of respiratory viruses circulating in Africa. Ultimately, this can guide vaccine and diagnostic development as well as performance assessment, aiding pandemic preparedness through the timely detection of emerging respiratory viruses.

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Measles Virus Genomic Surveillance Gaps during a Nationwide Outbreak, Bangladesh, 2026

Hasnain, N.; Shihab, S. F.; Islam, M. A.; Rahman, M. A.

2026-07-01 epidemiology 10.64898/2026.06.24.26356456 medRxiv
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Bangladesh reported a nationwide measles outbreak in April 2026 involving over 19,000 suspected cases, despite high reported first-dose vaccine coverage ([≥]95%). We assessed whether publicly available molecular data could support epidemiologic interpretation of this resurgence and evaluated broader sequence sharing practices across South Asia. We analyzed public outbreak reports, WHO/UNICEF Estimates of National Immunization Coverage (WUENIC), PubMed indexed literature, and NCBI GenBank records from nine regional countries. Public sequence visibility across the region was highly uneven. While India and Pakistan associated records dominated the public dataset, only 32 Bangladesh origin records were retrieved, and notably, none were collected after 2019. The sole 2026 Bangladesh linked molecular record was a travel associated genotype B3 genome isolated in Australia (PZ189094.1). Its closest public N450 relative was a contemporaneous Pakistan sequence (2-nucleotide difference). The historical Bangladesh sequences were more distant, precluding robust phylogenetic inference regarding local viral persistence, cross-border importation, or transmission direction. Immunization data revealed a high regional baseline but highlighted subnational vulnerability and a significant pandemic era coverage collapse in neighboring Myanmar. The absence of timely, publicly available genomic data during the critical early months of the outbreak highlights a severe genomic surveillance gap. Public molecular records were historically sparse and insufficient to reconstruct outbreak transmission dynamics. To support elimination goals, establishing targeted sequencing pipelines, enforcing minimum metadata standards, and ensuring rapid public data deposition are urgently needed. Keywords: measles; Bangladesh; South Asia; genomic surveillance; molecular epidemiology; immunization coverage

9
UV inactivation of bacteria and viruses on surfaces: mechanistic insights and testing method comparisons

Ma, B.; Seyedi, S.; Linden, K.

2026-06-24 microbiology 10.64898/2026.06.23.734141 medRxiv
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Germicidal UV devices offer a promising solution to mitigate surface-mediated pathogen transmission, providing effective disinfection without material corrosion. This study evaluated the surface inactivation kinetics of two bacteria and two bacteriophages using a low-pressure (LP) mercury UV lamp (254 nm) and a filtered krypton chloride (KrCl*) excimer lamp (222 nm). Three deposition methods (Spray, Spread, and Pipette) and two extraction methods (Swab and Elute) were compared. The UV dose response on surfaces followed a two-region non-linear model due to shielding from dried deposition constituents, primarily through UV absorption. KrCl* excimer exhibited similar bacterial inactivation but slightly lower viral inactivation than LP UV lamp (maximum inactivation [~] 1 log lower), but its safety profile makes it compelling in occupied spaces. Compared to aqueous conditions, bacteria were more UV sensitive on surfaces, whereas viruses were more resistant. The deposition methods affected the inactivation results, with the Spray method resulting in higher bacteria inactivation. While the extraction methods had limited effect on inactivation efficacy, the Swab method provided higher inactivation detection limits ([~] 2 log higher) and more consistent extraction efficiency. This study provides mechanistic insights into the effects of deposition conditions, UV wavelengths, and microbial characteristics on UV surface disinfection and contributes to standardization of testing methods. TOC Graphic O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=104 SRC="FIGDIR/small/734141v1_ufig1.gif" ALT="Figure 1"> View larger version (24K): org.highwire.dtl.DTLVardef@11db511org.highwire.dtl.DTLVardef@15aa3faorg.highwire.dtl.DTLVardef@1c39ac9org.highwire.dtl.DTLVardef@e726ed_HPS_FORMAT_FIGEXP M_FIG C_FIG

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Ruminococcus hollandia sp. nov. and Ruminococcus vasco sp. nov., two novel starch-degrading Ruminococcus isolated from the rumen of Holstein dairy cattle

Calapa, K. A.; Bock, R.; Embree, J.; LoBrutto, J.; Embree, M.

2026-07-11 microbiology 10.64898/2026.07.10.737842 medRxiv
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This study investigated the genomic and biochemical characteristics of two amylolytic microbial strains, NATIVEDY160T (= JE7B6T = NRRL B-68523T) and NATIVEDY161T (= JL13D9T, = NRRL B-68524T) isolated from the rumen of healthy Holstein dairy cattle. Both strains are obligately anaerobic, non-motile, Gram positive, catalase-negative, and oxidase-negative. Morphologically, NATIVEDY160T grows in long coccoid chains while NATIVEDY161T grows in short chains or pairs. NATIVEDY160T can catabolize amygdalin, esculin/ferric citrate, and starch, compared to NATIVEDY161T which utilizes amygdalin, arbutin, esculin/ferric citrate, glycogen, and D-maltose as determined by API 50 CH carbon panels. Starch degradation ability was verified for both strains, but neither showed cellulolytic activity as confirmed by starch agar and Congo red agar assays, respectively. HPLC analysis revealed that lactate was the primary end product of both strains carbohydrate fermentation, while strain NATIVEDY161T also produced small amounts of acetate. 16S rRNA sequences from both strains cluster with the Oscillospiraceae (formerly Ruminococcaceae) lineage Ruminococcus species, but average nucleotide identity of either strain compared to closely related Ruminococcus members was under the species threshold (95%). Genomic, phylogenetic, and phenotypic interrogation support NATIVEDY160T and NATIVEDY161T as novel species. Each strain was isolated from the rumen of dairy cows located within the central valley of southern California, which has a rich history of Dutch and Basque dairy farm ownership and is still the case today in the region. In recognition of the contributions and heritage of the central and southern California dairy industry, the names Ruminococcus hollandia and Ruminococcus vasco are proposed with NATIVEDY160T and NATIVEDY161T as their respective type strains.

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Isolation and characterisation of novel fruit bat alphaherpesvirus from Rousettus aegyptiacus bats in Coastal Kenya

Kisoi, G. K.; Bargul, J.; Kinyua, J.; Langat, S.; Koka, H.; Lutomiah, J.; Eyase, F.

2026-06-25 microbiology 10.64898/2026.06.25.734443 medRxiv
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BackgroundHerpesviruses are a group of double-stranded DNA viruses known to infect a wide range of vertebrates and establish life-long latent infections. While bats serve as natural reservoir hosts for numerous viral families, relatively few bat herpesviruses have been successfully isolated. In this study, we report the isolation and characterization of two novel alphaherpesvirus strains obtained from Rousettus aegyptiacus bats in Coastal Kenya. MethodsThe samples of oral and rectal swabs were collected from three different species of bats from coastal Kenya between October 2024 and April 2025; the bat species collected include Hipposideros spp., Coleura afra, and Rousettus aegyptiacus. Virus isolation was performed by inoculation of samples in Vero E6 cells and subsequent monitoring for cytopathic effects (CPE). Total nucleic acids were extracted from CPE positive cultures and subjected to library preparation to enable unbiased detection of both RNA and DNA viruses. The libraries were sequenced using next-generation sequencing with Illumina MiSeq platform. Subsequently, bioinformatic analysis was carried out to identify the virus, generate consensus genomes as well as phylogenetic analysis to determine the placement of identified viruses. ResultsTwo samples from R. aegyptiacus (KIK_460_O and KIK_465_O) induced typical CPE within five days. Sequencing and assembly yielded partial consensus sequences of approximately 60 kb (KIK_460_O) and 70 kb (KIK_465_O), representing extended genomic data for a bat-associated alphaherpesvirus. This virus has a genome of about 140kb, indicating that our partial assemblies account for about 43-50% of the total genome. Both isolates were found to be closely related to Dzifa herpesvirus, an alphaherpesvirus previously identified in Kilifi, Kenya. Alphaherpesvirus was identified based on partial sequencing of UL19 (3,787bp) and UL30 (2,846bp) genes. The two isolates were found to be identical at the UL19 gene, showing that they belonged to the same virus strain. Phylogenetic analysis showed that the novel alphaherpesvirus belongs to primate alphaherpesviruses under the subfamily Alphaherpesvirinae. ConclusionThis study reports the isolation and genomic characterization of a novel fruit bat alphaherpesvirus from Kenyan Rousettus aegyptiacus bats. The partial genome assembly (60-70 kb) represent the first extended genomic data for this virus, covering approximately 43-50% of the estimated 140 kb complete genome. The phylogenetic placement of this alphaherpesvirus near primate viruses, especially Pteropodid alphaherpesvirus 1, suggests bat-association and needs further investigation into its zoonotic potential.

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Anti-Human T-Lymphotropic Virus Type 1 (Htlv-1) Seropositivity In Haematological Malignancies At A Major Clinical Setting In Ghana

Awuku, F.; Omoniyi, P.; Adjei, D. N.; Seshie, M.; Sagoe, K. W. C.; Kuma, A. A. B.-A.

2026-07-10 infectious diseases 10.64898/2026.07.07.26357496 medRxiv
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Background Human T-cell lymphotropic virus - 1 (HTLV-1) is the causative agent of Adult T-cell Leukaemia/Lymphoma (ATLL), a malignancy of CD4+ cells, and HTLV-1-associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP), a demyelinating disease. Globally, 10-20 million people are infected, though most remain asymptomatic and about 5% progress to severe disease. Transmission occurs mainly through breastfeeding, sexual contact, contaminated needles, and blood transfusion. In Ghana, evidence on the role of HTLV-1 in haematological malignancies remains scarce. Methods This was a cross-sectional study involving 200 patients with haematological malignancies (Acute Lymphoblastic Leukaemia - 4, Acute Myeloid Leukaemia - 6, Chronic Lymphocytic Leukaemia - 27, Chronic Myeloid Leukaemia - 63, Hodgkin Lymphoma - 21, Multiple Myeloma - 31, Myelodysplasia - 6, Myeloproliferative Neoplasm - 11) at the Haematology Day Care of the Korle-Bu Teaching Hospital. After informed consent was obtained, sera from study participants were tested for anti-HTLV-1 using MP Diagnostics GmbH ELISA immunoassay. Data were analysed using R software version 4.0.2 and SPSS version 31.0.0. Results The study population had a mean age of 49.1{+/-}17.7 years, with majority being females (n=109, 54.5%). Of the 200 samples, 16 (8.0%) were seropositive for HTLV-1, and these were detected in 4 males and 12 females. No statistically significant association was found between HTLV-1 infection and haematological malignancy (exact p = 0.061), sex (p=0.061), and history of blood transfusion (exact p= 1.000). Conclusion The findings show the seroprevalence of HTLV-1 of 8.0% among patients with haematological malignancies. Although there was no probable association between HTLV-1 and haematological malignancies, screening for HTLV-1 in patients with haematological malignancies may help to unravel the exact contribution in these conditions.

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Hot Pursuit: Bioinformatic and Biochemical Characterization of a Hyperthermophilic Family B DNA Polymerase from Pyrolobus fumarii A1

Rusinek, W.; Dorawa, S.; Kaczorowski, T.

2026-06-26 biochemistry 10.64898/2026.06.25.734501 medRxiv
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Thermostable DNA polymerases are indispensable tools in molecular biology, yet enzymes from the most extreme hyperthermophiles remain largely uncharacterized. Here, we report the biochemical and structural characterization of a family B DNA polymerase from Pyrolobus fumarii A1 (Pyrfu pol), one of the most thermoresistant archaea described to date. The enzyme was efficiently overproduced in E. coli Rosetta 2(DE3)[pLysS] and purified to homogeneity using a two-step protocol that combined heat treatment with immobilized metal affinity chromatography (IMAC). Bioinformatic analysis confirmed the canonical family B architecture, while AlphaFold-based structural modeling and comparative analysis with mesophilic RB69 DNA polymerase revealed a well-conserved structural core alongside thermoadaptive features. Radiolabel incorporation assays demonstrated enzymatic activity over a broad ionic strength range and an absolute requirement for Mg ions. PCR-based optimization confirmed these findings and revealed broad pH tolerance (6.5-11.0). Notably, Tris inhibited radiolabel-based assays (pH 7.0) yet proved essential for efficient PCR amplification (pH 8.5), suggesting a context-dependent role of buffer composition in polymerase activity. Processivity assays confirmed amplification of DNA fragments up to approximately 8,000 bp. Replication fidelity, assessed by the lacZ-based assay, showed a 2.9-fold improvement over Taq polymerase. Urea-nanoDSF yielded an exceptional melting temperature of 105.9 {+/-} 0.08 {degrees}C. Pyrfu pol also demonstrated tolerance to common PCR inhibitors, highlighting its potential utility in molecular biology applications.

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Multidecadal Remote Sensing of Macrocystis Pyrifera in Argentina

Aguilar, A.; Pantano, C.; Houskeeper, H.; Bell, T.

2026-07-11 ecology 10.64898/2026.07.09.737405 medRxiv
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The Southern Hemisphere is home to extensive forests of giant kelp (Macrocystis pyrifera), including in Argentina and the southern islands of Tierra del Fuego, which has been proposed as a potential climate refugium. This study presents the first regional time series of M. pyrifera canopy dynamics in Argentina using Landsat satellite imagery from 1985 to 2023. The forests analyzed support 247.61 km{superscript 2} of emergent canopy and are situated in the coastal waters of Argentina and a small portion of Chilean islands, with 4%, 28%, and 68% in the Chubut, Santa Cruz, and Tierra del Fuego A.e.I.A.S, respectively. The small portion of Chilean Islands are included as part of the Tierra del Fuego province analyses. Range limits were scrutinized, in part, using expert knowledge and multisatellite comparisons. Linear regression shows that between 1998 and 2023, 7.4% of kelp sites exhibited a significant trend in annual canopy area, with all observed significant trends in the positive direction. Partitioning by province boundaries, linear regression produces significant positive increases in kelp canopy area across all three provinces, although reassessment when longer temporal continuity is also warranted, where available. Observed seawater nitrate concentrations were high throughout the region (7-23 {micro}mol L-{superscript 1}), suggesting that nitrate availability was not a primary driver of canopy variability. However, positive relationships between kelp canopy and the Antarctic Oscillation suggest that regional climate variability--which alters sea surface temperature and other oceanographic conditions--may be exerting a strong influence on kelp dynamics in this region. These findings document relative stability of kelp forest area in Argentina over the most recent two and a half decades and provide preliminary evidence supporting possible increases in kelp area for the region.

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High resolution Streptococcus pyogenes core genome MLST and LIN coding scheme for outbreak detection

Ryan, Y.; Jolley, K. A.; Hearn, H.; Parfitt, K. M.; Platt, S.; Lamagni, T.; Moganeradj, K.

2026-07-11 bioinformatics 10.64898/2026.07.10.737715 medRxiv
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Streptococcus pyogenes is a globally important pathogen responsible for at least 500,000 deaths a year, causing significant burden on healthcare systems. It is the causative agent for ailments such as impetigo and strep throat to septicaemia and necrotizing fasciitis. Assessment of genetic relatedness for the detection of outbreaks within communities or healthcare facilities is vital in decreasing the propagation of S. pyogenes within these settings, alongside epidemiological data. As the volume of isolates being sequenced increases year on year, more scalable and sharable methodologies of assessing genetic relatedness are required by reference laboratories and for international collaboration. LIN codes, applied to core genome MLST (cgMLST) represent a method which is extensible to large scale whole genome sequencing (WGS) while still being sufficiently sensitive to detect outbreak clusters. Here we present a novel cgMLST and LIN code scheme, hosted by PubMLST, enabling international collaboration and global tracking of variants, that is highly scalable and usable for all. The schemes are available at https://pubmlst.org/organisms/streptococcus-pyogenes. Data SummaryGenome sequences and metadata are available at https://pubmlst.org/organisms/streptococcus-pyogenes. PubMLST and ENA accessions and metadata can additionally be found in the supplementary data. Raw reads for UKHSA sequences are available in ENA study PRJEB115996. Impact StatementStreptococcus pyogenes is a globally relevant pathogen capable of causing invasive and non-invasive disease across a multitude of settings. Assessment of genetic relatedness is an increasingly important aspect of managing outbreaks, requiring solutions that are scalable, high resolution and comparable across laboratories. Here we present a high resolution core genome multi locus sequence typing (MLST) and associated life identification number (LIN) code scheme, The schemes were developed using a combination of 4,916 UKHSA and 2,391 publicly available S. pyogenes isolates in order to cover a wide range of EMM types both within the UK and globally. These new schemes enable high resolution typing of S. pyogenes isolates, suitable for analysis of lineages to genomic epidemiology in outbreak detection and management. Both cgMLST and LIN code schemes are available on PubMLST as an open access resource for the public health and academic communities and can enable both intra laboratory and global coordination.

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Diagnostic Utility of Endotracheal Aspirate Galactomannan for Invasive Pulmonary Aspergillosis in ICU Patients

Kumar, R.; Gupta, A.; Kumar, A.; Rao Kordcal, S.; Baitha, U.; Singh, G.; Xess, I.; Madan, K.; Soneja, M.; Wig, N.

2026-07-01 infectious diseases 10.64898/2026.06.29.26356826 medRxiv
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Background: Invasive pulmonary aspergillosis (IPA) is a serious infection in critically ill patients. Galactomannan detection in endotracheal aspirates (ETA) has emerged as a promising non-invasive diagnostic method. This study evaluates the supportive diagnostic value of ETA galactomannan in ICU patients suspected to have IPA. Methods: We conducted a prospective observational cohort study over two years, enrolling 120 patients in the medicine ICU at a tertiary care centre in India (January 2022 to October 2023). Patients aged over 14 years on mechanical ventilation for >48 hours meeting the entry criteria of the BM-AspICU algorithm were included. ETA galactomannan was measured and correlated with IPA classification. Results: Of 120 patients, 37% (n=44) had probable IPA and 63% (n=76) were classified as colonisers or possible IPA. The optimal ETA galactomannan cut-off was 1.097, yielding sensitivity 72.73% (95% CI 57.2 - 85.0%), specificity 84.2% (95% CI 74.4 - 90.7%), PLR 4.86, NLR 0.35, and AUC 0.844 Conclusion: ETA galactomannan supports IPA diagnosis with favourable sensitivity and specificity. However, given the limitations of clinical scoring-based reference standards and the potential plateau in colonizer reduction at higher cut-offs, it should be integrated into a comprehensive diagnostic approach incorporating clinical, radiological, and microbiological criteria.

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Diagnostic accuracy and acceptability of self- and health worker-collected tongue swabs for Mycobacterium tuberculosis complex detection in adults in South Africa

David, A.; Baik, Y.; Scott, L.; Kubeka, G.; Benoit, A.; Singh, L.; da Silva, P.; Stevens, W.; Bisson, G. P.; Charalambous, S.

2026-07-06 infectious diseases 10.64898/2026.07.04.26357275 medRxiv
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Tongue swabs (TSs) are a non invasive specimen type for the detection of Mycobacterium tuberculosis complex (MTBC) and can expand access to testing for individuals unable to produce sputum. This study evaluated the diagnostic performance and user acceptability of self collected and health worker (HW) collected tongue swabs using the Xpert MTB/RIF Ultra (Ultra) assay and assessed participant perspectives on self collection. In this prospective, cross sectional study, symptomatic and asymptomatic adults under investigation for TB were enrolled from a high HIV prevalence setting. Each participant provided both a self collected and a HW collected TS, which were tested using Ultra. Ultra TS results were compared to liquid culture as the reference standard and sputum Ultra as a comparator. Participant perspectives on self collection were captured via questionnaires. Sensitivity on Ultra for both self and HW collected TSs was 68% (95% CI:51.9 to 81.9), compared to liquid culture. This sensitivity was significantly higher than that of sputum smear microscopy (46%, 95% CI: 30.7 to 62.6; McNemar's p = 0.003). Tongue swab sensitivity was lower than sputum Ultra (80.5%; p<0.001) and decreased with low bacillary loads. Importantly, TSs enabled MTBC detection in six participants unable to produce sputum. Most participants (>90%) found self collection instructions easy to follow, reporting high confidence and comfort, and trust in results from self collected TSs. This study demonstrates that self collected TSs perform comparably to those collected by health workers for TB detection using Ultra and are both feasible and acceptable in a high TB/HIV burden setting. To maximize impact, clear training instructions and robust linkage to care remain critical priorities.

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Antifungal resistance mechanisms and nosocomial transmission of Nakaseomyces glabratus: genomic investigation and observational study in Melbourne, Australia

Gador-Whyte, A.; Seemann, T.; Judd, L. M.; Horan, K. A.; Lacey, J. A.; Traven, A.; Daniel, D.; Guerillot, R.; Giulieri, S.; Vogrin, S.; Aguilera, M. D.; Leroi, M.; Reynolds, G.; Howden, B. P.; Sherry, N. L.; Kwong, J. C.

2026-06-25 microbiology 10.64898/2026.06.22.733717 medRxiv
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Nakaseomyces glabratus (Candida glabrata) is a WHO high-priority fungal pathogen associated with fungal antimicrobial resistance (fAMR). Given nosocomial transmission occurs sporadically, resistant strains could be transmitted, a concern for critically ill patients. We conducted a genomic investigation and retrospective observational study of N. glabratus to identify any nosocomial transmission of fAMR and understand resistance mechanisms and clinical and demiological factors among patients at a quaternary hospital in Melbourne, Australia. We selected stored N. glabratus with and without fAMR associated with similar patient clinical characteristics and performed whole genome sequencing. Clinical and epidemiological data were extracted from medical records. Phylogenetic, mutational, copy-number variation (CNV) and mitochondrial genomic analyses were performed, with a focus on the fAMR gene PDR1. Of 54 isolates collected over seven years, 20 (37%) were fluconazole-resistant and four (7%) had elevated flucytosine minimum inhibitory concentrations (MICs) (range 2-32 g/ml). There were no significant clinical differences between patients with and without fluconazole resistance. Most (55%) fluconazole-resistant isolates carried PDR1 mutations. Resistance was distributed throughout the phylogeny suggesting predominantly independent acquisition. However, a cluster of four resistant isolates with the same PDR1 mutation suggested nosocomial transmission. One probable ERG11 gene duplication, and two petite variants with apparent mitochondrial genomic deletions, were seen in association with fluconazole resistance. In this study, we identified a small probable nosocomial fAMR transmission cluster, and novel variants in PDR1, ERG11 and FCY2 associated with fAMR phenotypes. Future study should confirm functional impacts and systematically investigate for nosocomial transmission of resistance, including colonisation states.

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Diagnostic accuracy and usability of the Pluslife MTB assay on tongue and sputum swabs in symptomatic and asymptomatic adults in South Africa

David, A.; Scott, L. E.; Singh, L.; Marokane, P.; da Silva, M. P.; Gast, D.; Noble, L.; Waja, Z.; Moloantoa, T.; Martinson, N.; Stevens, W.

2026-07-09 infectious diseases 10.64898/2026.06.28.26350594 medRxiv
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Background: Access to accurate tuberculosis (TB) diagnostics remains limited, particularly in high-burden settings. The Pluslife MTB assay is among the first molecular tests specifically designed for swab-based detection of Mycobacterium tuberculosis complex (MTBC) and offers near point-of-care use. Methods: We conducted a prospective diagnostic accuracy study in South Africa to evaluate the performance of the Pluslife assay on tongue swabs (TSs) and sputum swabs (SSs) among symptomatic and asymptomatic adults. Results were compared against liquid culture as the reference standard and Xpert MTB/RIF Ultra (Xpert Ultra) as a comparator. Operational characteristics and ease-of-use were assessed through structured observation and Likert-scale scoring by testing personnel. Results: Of 256 participants enrolled, 92 [36%] were people with HIV (PHIV) and 217 were included in the final analysis. Culture confirmed TB in 41/217 (19%). The Pluslife assay demonstrated sensitivity of 85% (95% CI: 70.8-94.4) on SSs, comparable to Xpert Ultra on sputum (83%, 95% CI: 67.9-92.8), and detected one additional case missed by Xpert Ultra. Sensitivity on TSs was lower (63%, 95% CI: 46.9-77.9), particularly among PHIV. Specificity exceeded 97% across specimen types. Concordance on TSs between Pluslife and Xpert Ultra increased with higher bacterial loads. Operational evaluation showed short hands-on time and high ease-of-use scores, though limitations were noted for patient identifier recording and troubleshooting on the Pluslife MiniDock device. Conclusions: The Pluslife MTB assay on SSs shows comparable performance to existing rapid diagnostics and favorable usability. Tongue swabs remain feasible but less reliable, supporting sputum as the preferred first specimen for TB diagnosis.

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The hand microbiome is sensitive to topical antibiotics and has varying sensitivity to liquid soaps

Stenton, M.; Henderson, S. R.

2026-06-30 microbiology 10.64898/2026.06.30.735469 medRxiv
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Hand eczema has been described as having an increased prevalence in persons with increased frequency of hand washing. This study investigated the differences in the hand microbiome of persons with and without a history of eczema and secondly the sensitivity of these microbes to commercial liquid soap as a potential trigger for eczema flares. The study identified Staphylococcus to be the most populus genus on the hands in both groups, but the distribution of species was different. Additionally, there was no difference in the number of soaps that produced zones of inhibition but there were some differences in the overall sensitivity to the different soaps tested. Overall, it was determined that liquid soap can cause bactericidal effects on some species of the commensal microbiome, but further work is required to determine if this could be the cause of hand eczema.