Gut resistome linked to sexual preference and HIV infection.

BACKGROUND: People living with HIV (PLWH) are at increased risk of acquisition of multidrug resistant organisms due to higher rates of predisposing factors. The gut microbiome is the main reservoir of the collection of antimicrobial resistance determinants known as the gut resistome. In PLWH, changes in gut microbiome have been linked to immune activation and HIV-1 associated complications. Specifically, gut dysbiosis defined by low microbial gene richness has been linked to low Nadir CD4 + T-cell counts. Additionally, sexual preference has been shown to strongly influence gut microbiome composition in PLWH resulting in different Prevotella or Bacteroides enriched enterotypes, in MSM (men-who-have-sex-with-men) or no-MSM, respectively. To date, little is known about gut resistome composition in PLWH due to the scarcity of studies using shotgun metagenomics. The present study aimed to detect associations between different microbiome features linked to HIV-1 infection and gut resistome composition. RESULTS: Using shotgun metagenomics we characterized the gut resistome composition of 129 HIV-1 infected subjects showing different HIV clinical profiles and 27 HIV-1 negative controls from a cross-sectional observational study conducted in Barcelona, Spain. Most no-MSM showed a Bacteroides-enriched enterotype and low microbial gene richness microbiomes. We did not identify differences in resistome diversity and composition according to HIV-1 infection or immune status. However, gut resistome was more diverse in MSM group, Prevotella-enriched enterotype and gut micorbiomes with high microbial gene richness compared to no-MSM group, Bacteroides-enriched enterotype and gut microbiomes with low microbial gene richness. Additionally, gut resistome beta-diversity was different according to the defined groups and we identified a set of differentially abundant antimicrobial resistance determinants based on the established categories. CONCLUSIONS: Our findings reveal a significant correlation between gut resistome composition and various host variables commonly associated with gut microbiome, including microbiome enterotype, microbial gene richness, and sexual preference. These host variables have been previously linked to immune activation and lower Nadir CD4 + T-Cell counts, which are prognostic factors of HIV-related comorbidities. This study provides new insights into the relationship between antibiotic resistance and clinical characteristics of PLWH.

Vaccination with an HIV T-Cell Immunogen (HTI) Using DNA Primes Followed by a ChAdOx1-MVA Boost Is Immunogenic in Gut Microbiota-Depleted Mice despite Low IL-22 Serum Levels.

Despite the important role of gut microbiota in the maturation of the immune system, little is known about its impact on the development of T-cell responses to vaccination. Here, we immunized C57BL/6 mice with a prime-boost regimen using DNA plasmid, the Chimpanzee Adenovirus, and the modified Vaccinia Ankara virus expressing a candidate HIV T-cell immunogen and compared the T-cell responses between individuals with an intact or antibiotic-depleted microbiota. Overall, the depletion of the gut microbiota did not result in significant differences in the magnitude or breadth of the immunogen-specific IFNγ T-cell response after vaccination. However, we observed marked changes in the serum levels of four cytokines after vaccinating microbiota-depleted animals, particularly a significant reduction in IL-22 levels. Interestingly, the level of IL-22 in serum correlated with the abundance of Roseburia in the large intestine of mice in the mock and vaccinated groups with intact microbiota. This short-chain fatty acid (SCFA)-producing bacterium was significantly reduced in the vaccinated, microbiota-depleted group. Therefore, our results indicate that, although microbiota depletion reduces serum levels of IL-22, the powerful vaccine regime used could have overcome the impact of microbiota depletion on IFNγ-producing T-cell responses.

Switching to bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) plus darunavir/cobicistat in heavily antiretroviral-experienced, virologically suppressed HIV-infected adults receiving complex regimens.

OBJECTIVES: To evaluate the efficacy and safety of the two-pill regimen bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) plus darunavir/cobicistat as a switching strategy in heavily treatment-experienced people living with HIV (PLWH). METHODS: Multicentre, prospective, single-arm pilot clinical trial. Participants were virologically suppressed adults receiving a stable antiretroviral regimen of at least three pills from at least three drug families due to previous virological failures and/or toxicities with no documented resistance to integrase strand transfer inhibitors or darunavir (≥15 points, Stanford). Clinical and laboratory assessments were performed at 0, 4, 12, 24, 36 and 48 weeks. HIV-1 proviral DNA was amplified and sequenced by Illumina at baseline. Plasma bictegravir concentrations were determined in 22 patients using UHPLC-MS/MS. The primary study endpoint was viral load (VL)< 50 copies/mL at Week 48 (ITT). RESULTS: We enrolled 63 participants (92% men) with median baseline CD4 count of 515 cells/mm3 (IQR: 334.5-734.5), 24 years on ART (IQR: 15.9-27.8). The median number of pills was 4 (range: 3-10). At baseline, proviral DNA was amplified in 39 participants: 33/39 had resistance mutations. Three participants discontinued owing to toxicity. At 48 weeks, 95% had VL < 50 copies/mL by ITT and 100% by PP analysis. A modest increase was observed in the bictegravir plasma concentration, and a significant decrease in estimated glomerular filtration rate was observed only at Week 4, probably related to interaction with renal transporters. CONCLUSIONS: Our data suggest that BIC/FTC/TAF + darunavir/cobicistat is an effective, well-tolerated regimen that may improve convenience and, potentially, long-term success in stable heavily pre-treated PLWH.

Probiotic effects on immunity and microbiome in HIV-1 discordant patients.

Background: Some HIV-1 infected patients are unable to completely recover normal CD4+ T-cell (CD4+) counts after achieving HIV-1 suppression with combined Antiretroviral Therapy (cART), hence being classified as immuno-discordant. The human microbiome plays a crucial role in maintaining immune homeostasis and is a potential target towards immune reconstitution. Setting: RECOVER (NCT03542786) was a double-blind placebo-controlled clinical trial designed to evaluate if the novel probiotic i3.1 (AB-Biotics, Sant Cugat del Vallès, Spain) was able to improve immune reconstitution in HIV-1 infected immuno-discordant patients with stable cART and CD4+ counts <500 cells/mm3. The mixture consisted of two strains of L. plantarum and one of P. acidilactici, given with or without a fiber-based prebiotic. Methods: 71 patients were randomized 1:2:2 to Placebo, Probiotic or probiotic + prebiotic (Synbiotic), and were followed over 6 months + 3-month washout period, in which changes on systemic immune status and gut microbiome were evaluated. Primary endpoints were safety and tolerability of the investigational product. Secondary endpoints were changes on CD4+ and CD8+ T-cell (CD8+) counts, inflammation markers and faecal microbiome structure, defined by alpha diversity (Gene Richness), beta diversity (Bray-Curtis) and functional profile. Comparisons across/within groups were performed using standard/paired Wilcoxon test, respectively. Results: Adverse event (AE) incidence was similar among groups (53%, 33%, and 55% in the Placebo, Probiotic and Synbiotic groups, respectively, the most common being grade 1 digestive AEs: flatulence, bloating and diarrhoea. Two grade 3 AEs were reported, all in the Synbiotic group: abdominal distension (possibly related) and malignant lung neoplasm (unrelated), and 1 grade 4 AE in the Placebo: hepatocarcinoma (unrelated). Synbiotic exposure was associated with a higher increase in CD4+/CD8+ T-cell (CD4/CD8) ratio at 6 months vs baseline (median=0.76(IQR=0.51) vs 0.72(0. 45), median change= 0.04(IQR=0.19), p = 0.03). At month 9, the Synbiotic group had a significant increase in CD4/CD8 ratio (0.827(0.55) vs 0.825(0.53), median change = 0.04(IQR=0.15), p= 0.02) relative to baseline, and higher CD4+ counts (447 (157) vs. 342(73) counts/ml, p = 0.03), and lower sCD14 values (2.16(0.67) vs 3.18(0.8), p = 0.008) than Placebo. No effect in immune parameters was observed in the Probiotic arm. None of the two interventions modified microbial gene richness (alpha diversity). However, intervention as categorical variable was associated with slight but significant effect on Bray-Curtis distance variance (Adonis R2 = 0.02, p = 0.005). Additionally, at month 6, Synbiotic intervention was associated with lower pathway abundances vs Placebo of Assimilatory Sulphate Reduction (8.79·10-6 (1.25·10-5) vs. 1.61·10-5 (2.77·10-5), p = 0.03) and biosynthesis of methionine (2.3·10-5 (3.17·10-5) vs. 4·10-5 (5.66·10-5), p = 0.03) and cysteine (1.83·10-5 (2.56·10-5) vs. 3.3·10-5 (4.62·10-5), p = 0.03). At month 6, probiotic detection in faeces was associated with significant decreases in C Reactive Protein (CRP) vs baseline (11.1(22) vs. 19.2(66), median change= -2.7 (13.2) ug/ml, p = 0.04) and lower IL-6 values (0.58(1.13) vs. 1.17(1.59) ug/ml, p = 0.02) when compared with samples with no detectable probiotic. No detection of the probiotic was associated with higher CD4/CD8 ratio at month 6 vs baseline (0.718(0.57) vs. 0.58(0.4), median change = 0.4(0.2), p = 0.02). After washout, probiotic non-detection was also associated with a significant increase in CD4+ counts (457(153) vs. 416(142), median change = 45(75), counts/ml, p = 0.005) and CD4/CD8 ratio (0.67(0.5) vs 0.59(0.49), median change = 0.04 (0.18), p = 0.02). Conclusion: A synbiotic intervention with L. plantarum and P. acidilactici was safe and led to small increases in CD4/CD8 ratio and minor reductions in sCD14 of uncertain clinical significance. A probiotic with the same composition was also safe but did not achieve any impact on immune parameters or faecal microbiome composition.

Monitoring SARS-CoV-2 variant transitions using differences in diagnostic cycle threshold values of target genes.

Monitoring the emergence of new SARS-CoV-2 variants is important to detect potential risks of increased transmission or disease severity. We investigated the identification of SARS-CoV-2 variants from real-time reverse transcriptase polymerase chain reaction (RT-PCR) routine diagnostics data. Cycle threshold (Ct) values of positive samples were collected from April 2021 to January 2022 in the Northern Metropolitan Area of Barcelona (n = 15,254). Viral lineage identification from whole genome sequencing (WGS) was available for 4618 (30.3%) of these samples. Pairwise differences in the Ct values between gene targets (ΔCt) were analyzed for variants of concern or interest circulating in our area. A specific delay in the Ct of the N-gene compared to the RdRp-gene (ΔCtNR) was observed for Alpha, Delta, Eta and Omicron. Temporal differences in ΔCtNR correlated with the dynamics of viral replacement of Alpha by Delta and of Delta by Omicron according to WGS results. Using ΔCtNR, prediction of new variants of concern at early stages of circulation was achieved with high sensitivity and specificity (91.1% and 97.8% for Delta; 98.5% and 90.8% for Omicron). Thus, tracking population-wide trends in ΔCt values obtained from routine diagnostics testing in combination with WGS could be useful for real-time management and response to local epidemics.

Vaccination with an HIV T-cell immunogen induces alterations in the mouse gut microbiota.

The gut microbiota is emerging as a crucial factor modulating vaccine responses; however, few studies have investigated if vaccines, in turn, can alter the microbiota and to what extent such changes may improve vaccine efficacy. To understand the effect of T-cell vaccination on the gut microbiome, we administered an HIV-1 T-cell immunogen (HTI arm) or PBS (control, Mock arm) to C57Bl/6 mice following a heterologous prime-boost scheme. The longitudinal dynamics of the mice gut microbiota was characterized by 16 S ribosomal RNA sequencing in fecal samples collected from cages, as well as from three gut sections (cecum, small and large intestine). Serum and spleen cells were obtained at the last time point of the study to assess immune correlates using IFNγ ELISPOT and cytokine Luminex® assays. Compared with Mock, HTI-vaccinated mice were enriched in Clostridiales genera (Eubacterium xylanophilum group, Roseburia and Ruminococcus) known as primary contributors of anti-inflammatory metabolites, such as short-chain fatty acids. Such shift was observed after the first HTI dose and remained throughout the study follow-up (18 weeks). However, the enriched Clostridiales genera were different between feces and gut sections. The abundance of bacteria enriched in vaccinated animals positively correlated with HTI-specific T-cell responses and a set of pro-inflammatory cytokines, such as IL-6. This longitudinal analysis indicates that, in mice, T-cell vaccination may promote an increase in gut bacteria known to produce anti-inflammatory molecules, which in turn correlate with proinflammatory cytokines, suggesting an adaptation of the gut microbial milieu to T-cell-induced systemic inflammation.

Safety, immunogenicity and effect on viral rebound of HTI vaccines in early treated HIV-1 infection: a randomized, placebo-controlled phase 1 trial.

HIVACAT T-cell immunogen (HTI) is a novel human immunodeficiency virus (HIV) vaccine immunogen designed to elicit cellular immune responses to HIV targets associated with viral control in humans. The AELIX-002 trial was a randomized, placebo-controlled trial to evaluate as a primary objective the safety of a combination of DNA.HTI (D), MVA.HTI (M) and ChAdOx1.HTI (C) vaccines in 45 early-antiretroviral (ART)-treated individuals (44 men, 1 woman; NCT03204617). Secondary objectives included T-cell immunogenicity, the effect on viral rebound and the safety of an antiretroviral treatment interruption (ATI). Adverse events were mostly mild and transient. No related serious adverse events were observed. We show here that HTI vaccines were able to induce strong, polyfunctional and broad CD4 and CD8 T-cell responses. All participants experienced detectable viral rebound during ATI, and resumed ART when plasma HIV-1 viral load reached either >100,000 copies ml-1, >10,000 copies ml-1 for eight consecutive weeks, or after 24 weeks of ATI. In post-hoc analyses, HTI vaccines were associated with a prolonged time off ART in vaccinees without beneficial HLA (human leukocyte antigen) class I alleles. Plasma viral load at the end of ATI and time off ART positively correlated with vaccine-induced HTI-specific T-cell responses at ART cessation. Despite limited efficacy of the vaccines in preventing viral rebound, their ability to elicit robust T-cell responses towards HTI may be beneficial in combination cure strategies, which are currently being tested in clinical trials.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and humoral responses against different variants of concern in domestic pet animals and stray cats from North-Eastern Spain.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of the coronavirus disease 2019 (COVID-19) pandemic in humans, is able to infect several domestic, captive and wildlife animal species. Since reverse zoonotic transmission to pets has been demonstrated, it is crucial to determine their role in the epidemiology of the disease to prevent further spillover events and major spread of SARS-CoV-2. In the present study, we determined the presence of virus and the seroprevalence to SARS-CoV-2, as well as the levels of neutralizing antibodies (nAbs) against several variants of concern (VOCs) in pets (cats, dogs and ferrets) and stray cats from North-Eastern of Spain. We confirmed that cats and dogs can be infected by different VOCs of SARS-CoV-2 and, together with ferrets, are able to develop nAbs against the ancestral (B.1), Alpha (B.1.1.7), Beta (B.1.315), Delta (B.1.617.2) and Omicron (BA.1) variants, with lower titres against the latest in dogs and cats, but not in ferrets. Although the prevalence of active SARS-CoV-2 infection measured as direct viral RNA detection was low (0.3%), presence of nAbs in pets living in COVID-19-positive households was relatively high (close to 25% in cats, 10% in dogs and 40% in ferrets). It is essential to continue monitoring SARS-CoV-2 infections in these animals due to their frequent contact with human populations, and we cannot discard the probability of a higher animal susceptibility to new potential SARS-CoV-2 VOCs.

Gut microbiome signatures linked to HIV-1 reservoir size and viremia control.

BACKGROUND: The potential role of the gut microbiome as a predictor of immune-mediated HIV-1 control in the absence of antiretroviral therapy (ART) is still unknown. In the BCN02 clinical trial, which combined the MVA.HIVconsv immunogen with the latency-reversing agent romidepsin in early-ART treated HIV-1 infected individuals, 23% (3/13) of participants showed sustained low-levels of plasma viremia during 32 weeks of a monitored ART pause (MAP). Here, we present a multi-omics analysis to identify compositional and functional gut microbiome patterns associated with HIV-1 control in the BCN02 trial. RESULTS: Viremic controllers during the MAP (controllers) exhibited higher Bacteroidales/Clostridiales ratio and lower microbial gene richness before vaccination and throughout the study intervention when compared to non-controllers. Longitudinal assessment indicated that the gut microbiome of controllers was enriched in pro-inflammatory bacteria and depleted in butyrate-producing bacteria and methanogenic archaea. Functional profiling also showed that metabolic pathways related to fatty acid and lipid biosynthesis were significantly increased in controllers. Fecal metaproteome analyses confirmed that baseline functional differences were mainly driven by Clostridiales. Participants with high baseline Bacteroidales/Clostridiales ratio had increased pre-existing immune activation-related transcripts. The Bacteroidales/Clostridiales ratio as well as host immune-activation signatures inversely correlated with HIV-1 reservoir size. CONCLUSIONS: The present proof-of-concept study suggests the Bacteroidales/Clostridiales ratio as a novel gut microbiome signature associated with HIV-1 reservoir size and immune-mediated viral control after ART interruption. Video abstract.

Integrase resistance emergence with dolutegravir/lamivudine with prior HIV-1 suppression.

OBJECTIVES: Integrase resistance has not been reported with co-formulated dolutegravir/lamivudine in clinical trials or real-life cohorts. We aim to report, to the best of our knowledge, the first case of selection of the key integrase mutation R263K in a subject treated with this regimen started as a switch strategy with undetectable plasma HIV-1 viraemia. METHODS: Clinical case report. RESULTS: A patient with long-term suppressed HIV-1 viraemia (<50 copies/mL) with no known risk factors for virological failure and never exposed previously to an integrase inhibitor developed virological failure (consecutive plasma HIV-1 RNA 149 and 272 copies/mL) with 322 CD4 cells/mm3 despite good treatment adherence. He was receiving the anticonvulsant clobazam, considered to have a potential weak interaction with dolutegravir, unlikely to require a dose adjustment. Plasma HIV-1 genotypic deep sequencing (Vela System) revealed the emergence of R263K (79.6%) and S230N (99.4%) mutations in the integrase region (intermediate resistance to dolutegravir, score = 30 Stanford HIVDB 9.0). The reverse transcriptase and protease regions could not be amplified due to low viral loads. PBMC DNA deep sequencing performed some months later revealed mutations M184I (14.29%) and M230I (6.25%) in the reverse transcriptase and G163R (9.77%) and S230N (98.8%) in the integrase. R263K was only found at extremely low levels (0.07%). CONCLUSIONS: This case illustrates that integrase resistance can emerge in patients treated with co-formulated dolutegravir/lamivudine and raises awareness of the need to carefully consider and monitor drug-drug interactions, even when regarded as having a low potential, in subjects treated with dolutegravir/lamivudine.

First Detection of SARS-CoV-2 Delta (B.1.617.2) Variant of Concern in a Dog with Clinical Signs in Spain.

Several cases of naturally infected dogs with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been reported despite the apparently low susceptibility of this species. Here, we document the first reported case of infection caused by the Delta (B.1.617.2) variant of concern (VOC) in a dog in Spain that lived with several household members suffering from Coronavirus Infectious Disease 2019 (COVID-19). The animal displayed mild digestive and respiratory clinical signs and had a low viral load in the oropharyngeal swab collected at the first sampling. Whole-genome sequencing indicated infection with the Delta variant, coinciding with the predominant variant during the fifth pandemic wave in Spain. The dog seroconverted, as detected 21 days after the first sampling, and developed neutralizing antibodies that cross-neutralized different SARS-CoV-2 variants. This study further emphasizes the importance of studying the susceptibility of animal species to different VOCs and their potential role as reservoirs in the context of COVID-19.

Performance of 16S Metagenomic Profiling in Formalin-Fixed Paraffin-Embedded versus Fresh-Frozen Colorectal Cancer Tissues.

Formalin-fixed, paraffin-embedded (FFPE) tissues represent the most widely available clinical material to study colorectal cancer (CRC). However, the accuracy and clinical validity of FFPE microbiome profiling in CRC is uncertain. Here, we compared the microbial composition of 10 paired fresh-frozen (FF) and FFPE CRC tissues using 16S rRNA sequencing and RNA-ISH. Both sample types showed different microbial diversity and composition. FF samples were enriched in archaea and representative CRC-associated bacteria, such as Firmicutes, Bacteroidetes and Fusobacteria. Conversely, FFPE samples were mainly enriched in typical contaminants, such as Sphingomonadales and Rhodobacterales. RNA-ISH in FFPE tissues confirmed the presence of CRC-associated bacteria, such as Fusobacterium and Bacteroides, as well as Propionibacterium allowing discrimination between tumor-associated and contaminant taxa. An internal quality index showed that the degree of similarity within sample pairs inversely correlated with the dominance of contaminant taxa. Given the importance of FFPE specimens for larger studies in human cancer genomics, our findings may provide useful indications on potential confounding factors to consider for accurate and reproducible metagenomics analyses.

Monitoring Natural SARS-CoV-2 Infection in Lions (Panthera leo) at the Barcelona Zoo: Viral Dynamics and Host Responses.

To date, no evidence supports the fact that animals play a role in the epidemiology of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of the coronavirus infectious disease 2019 (COVID-19). However, several animal species are naturally susceptible to SARS-CoV-2 infection. Besides pets (cats, dogs, Syrian hamsters, and ferrets) and farm animals (minks), different zoo animal species have tested positive for SARS-CoV-2 (large felids and non-human primates). After the summer of 2020, a second wave of SARS-CoV-2 infection occurred in Barcelona (Spain), reaching a peak of positive cases in November. During that period, four lions (Panthera leo) at the Barcelona Zoo and three caretakers developed respiratory signs and tested positive for the SARS-CoV-2 antigen. Lion infection was monitored for several weeks and nasal, fecal, saliva, and blood samples were taken at different time-points. SARS-CoV-2 RNA was detected in nasal samples from all studied lions and the viral RNA was detected up to two weeks after the initial viral positive test in three out of four animals. The SARS-CoV-2 genome was also detected in the feces of animals at different times. Virus isolation was successful only from respiratory samples of two lions at an early time-point. The four animals developed neutralizing antibodies after the infection that were detectable four months after the initial diagnosis. The partial SARS-CoV-2 genome sequence from one animal caretaker was identical to the sequences obtained from lions. Chronology of the events, the viral dynamics, and the genomic data support human-to-lion transmission as the origin of infection.

Critical Presentation of a Severe Acute Respiratory Syndrome Coronavirus 2 Reinfection: A Case Report.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reinfections have been reported; however, most cases are milder than the primary infection. We report the first case of a life-threatening critical presentation of a SARS-CoV-2 reinfection. METHODS: A 62-year-old man from Palamós (Spain) suffered a first mild coronavirus disease 2019 (COVID-19) episode in March 2020, confirmed by 2 independent SARS-CoV-2 nasopharyngeal polymerase chain reaction (PCR) assays and a normal radiograph. He recovered completely and tested negative on 2 consecutive PCRs. In August 2020, the patient developed a second SARS-CoV-2 infection with life-threatening bilateral pneumonia and Acute respiratory distress syndrome criteria, requiring COVID-19-specific treatment (remdesivir + dexamethasone) plus high-flow oxygen therapy. Nasopharyngeal swabs from the second episode were obtained for virus quantification by real-time PCR, for virus outgrowth and sequencing. In addition, plasma and peripheral blood mononuclear cells during the hospitalization period were used to determine SARS-CoV-2-specific humoral and T-cell responses. RESULTS: Genomic analysis of SARS-CoV-2 showed that the virus had probably originated shortly before symptom onset. When the reinfection occurred, the subject showed a weak immune response, with marginal humoral and specific T-cell responses against SARS-CoV-2. All antibody isotypes tested as well as SARS-CoV-2 neutralizing antibodies increased sharply after day 8 postsymptoms. A slight increase of T-cell responses was observed at day 19 after symptom onset. CONCLUSIONS: The reinfection was firmly documented and occurred in the absence of robust preexisting humoral and cellular immunity. SARS-CoV-2 immunity in some subjects is unprotective and/or short-lived; therefore, SARS-CoV-2 vaccine schedules inducing long-term immunity will be required to bring the pandemic under control.

Detection of SARS-CoV-2 in a cat owned by a COVID-19-affected patient in Spain.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiological agent of COVID-19, is considered a zoonotic pathogen mainly transmitted human to human. Few reports indicate that pets may be exposed to the virus. The present report describes a cat suffering from severe respiratory distress and thrombocytopenia living with a family with several members affected by COVID-19. Clinical signs of the cat prompted humanitarian euthanasia and a detailed postmortem investigation to assess whether a COVID-19-like disease was causing the condition. Necropsy results showed the animal suffered from feline hypertrophic cardiomyopathy and severe pulmonary edema and thrombosis. SARS-CoV-2 RNA was only detected in nasal swab, nasal turbinates, and mesenteric lymph node, but no evidence of histopathological lesions compatible with a viral infection were detected. The cat seroconverted against SARS-CoV-2, further evidencing a productive infection in this animal. We conclude that the animal had a subclinical SARS-CoV-2 infection concomitant to an unrelated cardiomyopathy that led to euthanasia.

Yaws re-emergence and bacterial drug resistance selection after mass administration of azithromycin: a genomic epidemiology investigation.

BACKGROUND: In a longitudinal study assessing the WHO strategy for yaws eradication using mass azithromycin treatment, we observed resurgence of yaws cases with dominance of a single JG8 sequence type and emergence of azithromycin-resistant Treponema pallidum subspecies pertenue (T p pertenue). Here, we analyse genomic changes in the bacterial population using samples collected during the study. METHODS: We did whole bacterial genome sequencing directly on DNA extracted from 37 skin lesion swabs collected from patients on Lihir Island, Papua New Guinea, between April 1, 2013, and Nov 1, 2016. We produced phylogenies and correlated these with spatiotemporal information to investigate the source of new cases and the emergence of five macrolide-resistant cases. We used deep amplicon sequencing of surveillance samples to assess the presence of minority macrolide-resistant populations. FINDINGS: We recovered 20 whole T p pertenue genomes, and phylogenetic analysis showed that the re-emerging JG8 sequence type was composed of three bacterial sublineages characterised by distinct spatiotemporal patterns. Of five patients with resistant T p pertenue, all epidemiologically linked, we recovered genomes from three and found no variants. Deep sequencing showed that before treatment, the index patient had fixed macrolide-sensitive T p pertenue, whereas the post-treatment sample had a fixed resistant genotype, as did three of four contact cases. INTERPRETATION: In this study, re-emergence of yaws cases was polyphyletic, indicating multiple epidemiological sources. However, given the genomic and epidemiological linkage of resistant cases and the rarity of resistance alleles in the general population, azithromycin resistance is likely to have evolved only once in this study, followed by onward dissemination. FUNDING: Wellcome and Provincial Deputation of Barcelona.

Exploring interactions between Blastocystis sp., Strongyloides spp. and the gut microbiomes of wild chimpanzees in Senegal.

BACKGROUND: Gut parasites exert an important influence on the gut microbiome, with many studies focusing on the human gut microbiome. It has, however, undergone severe richness depletion. Hygienic lifestyle, antimicrobial treatments and altered gut homeostasis (e.g., chronic inflammation) reduce gut microbiome richness and also parasite prevalence; which may confound results. Studying species closely related to humans could help overcome this problem by providing insights into the ancestral relationship between humans, their gut microbiome and their gut parasites. Chimpanzees are a particularly promising model as they have similar gut microbiomes to humans and many parasites infect both species. AIMS: We study the interaction between gut microbiome and enteric parasites in chimpanzees. Investigating what novel insights a closely related species can reveal when compared to studies on humans. METHODS: Using eighty-seven faecal samples from wild western chimpanzees (Pan troglodytes verus) in Senegal, we combine 16S rRNA gene amplicon sequencing for gut microbiome characterization with PCR detection of parasite taxa (Blastocystis sp., Strongyloides spp., Giardia duodenalis, Cryptosporidium spp., Plasmodium spp., Filariae and Trypanosomatidae). We test for differences in gut microbiota ecosystem traits and taxonomical composition between Blastocystis and Strongyloides bearing and non-bearing samples. RESULTS: For Blastocystis, twelve differentially abundant taxa (e.g., Methanobrevibacter), including Prevotella and Ruminococcus-Methanobrevibacter enterotype markers, replicate findings in humans. However, several richness indices are lower in Blastocystis carriers, contradicting human studies. This indicates Blastocystis, unlike Strongyloides, is associated to a "poor health" gut microbiome, as does the fact that Faecalibacterium, a bacterium with gut protective traits, is absent in Blastocystis-positive samples. Strongyloides was associated to Alloprevotella and five other taxonomic groups. Each parasite had its unique impact on the gut microbiota indicating parasite-specific niches. Our results suggest that studying the gut microbiomes of wild chimpanzees could help disentangle biological from artefactual associations between gut microbiomes and parasites.

Evolution of the gut microbiome following acute HIV-1 infection.

BACKGROUND: In rhesus macaques, simian immunodeficiency virus infection is followed by expansion of enteric viruses but has a limited impact on the gut bacteriome. To understand the longitudinal effects of HIV-1 infection on the human gut microbiota, we prospectively followed 49 Mozambican subjects diagnosed with recent HIV-1 infection (RHI) and 54 HIV-1-negative controls for 9-18 months and compared them with 98 chronically HIV-1-infected subjects treated with antiretrovirals (n = 27) or not (n = 71). RESULTS: We show that RHI is followed by increased fecal adenovirus shedding, which persists during chronic HIV-1 infection and does not resolve with ART. Recent HIV-1 infection is also followed by transient non-HIV-specific changes in the gut bacterial richness and composition. Despite early resilience to change, an HIV-1-specific signature in the gut bacteriome-featuring depletion of Akkermansia, Anaerovibrio, Bifidobacterium, and Clostridium-previously associated with chronic inflammation, CD8+ T cell anergy, and metabolic disorders, can be eventually identified in chronically HIV-1-infected subjects. CONCLUSIONS: Recent HIV-1 infection is associated with increased fecal shedding of eukaryotic viruses, transient loss of bacterial taxonomic richness, and long-term reductions in microbial gene richness. An HIV-1-associated microbiome signature only becomes evident in chronically HIV-1-infected subjects.

Low nadir CD4+ T-cell counts predict gut dysbiosis in HIV-1 infection.

Human immunodeficiency virus (HIV)-1 infection causes severe gut and systemic immune damage, but its effects on the gut microbiome remain unclear. Previous shotgun metagenomic studies in HIV-negative subjects linked low-microbial gene counts (LGC) to gut dysbiosis in diseases featuring intestinal inflammation. Using a similar approach in 156 subjects with different HIV-1 phenotypes, we found a strong, independent, dose-effect association between nadir CD4+ T-cell counts and LGC. As in other diseases involving intestinal inflammation, the gut microbiomes of subjects with LGC were enriched in gram-negative Bacteroides, acetogenic bacteria and Proteobacteria, which are able to metabolize reactive oxygen and nitrogen species; and were depleted in oxygen-sensitive methanogenic archaea and sulfate-reducing bacteria. Interestingly, subjects with LGC also showed increased butyrate levels in direct fecal measurements, consistent with enrichment in Roseburia intestinalis despite reductions in other butyrate producers. The microbiomes of subjects with LGC were also enriched in bacterial virulence factors, as well as in genes associated with beta-lactam, lincosamide, tetracycline, and macrolide resistance. Thus, low nadir CD4+ T-cell counts, rather than HIV-1 serostatus per se, predict the presence of gut dysbiosis in HIV-1 infected subjects. Such dysbiosis does not display obvious HIV-specific features; instead, it shares many similarities with other diseases featuring gut inflammation.

Etiological Characterization of the Cutaneous Ulcer Syndrome in Papua New Guinea Using Shotgun Metagenomics.

Background: Treponema pallidum subsp pertenue and Haemophilus ducreyi are causative agents of cutaneous ulcer (CU) in yaws-endemic regions in the tropics. However, a significant proportion of CU patients remain polymerase chain reaction (PCR) negative for both bacterial agents. We aimed to identify potential additional etiological agents of CU in a yaws-endemic region. Methods: This population-based cohort study included children in Lihir Island (Papua New Guinea) examined during a yaws eradication campaign in October 2013-October 2014. All consenting patients with atraumatic exudative ulcers of >1 cm diameter were enrolled. Lesional swabs were collected for real-time PCR testing for T. pallidum subsp pertenue and H. ducreyi. We then performed shotgun whole DNA metagenomics sequencing on extracted DNA and taxonomically assigned shotgun sequences using a human microbiome reference. Results: Sequence data were available for 122 samples. Shotgun sequencing showed high classification agreement relative to PCR testing (area under the curve for T. pallidum/H. ducreyi was 0.92/0.85, respectively). Clustering analysis of shotgun data revealed compositional clusters where the dominant species (median relative abundance ranged from 32% to 66%) was H. ducreyi (23% of specimens), T. pallidum subsp pertenue (16%), Streptococcus dysgalactiae (12%), Arcanobacterium haemolyticum (8%), and Corynebacterium diphtheriae (8%). Sample clustering derived from ulcer microbial composition did not show geographical patterns. Conclusions: These data suggest a diverse etiology of skin ulcers in yaws-endemic areas, which may help design more accurate diagnostic tools and more effective antimicrobial treatment approaches to the cutaneous ulcer syndrome.