Detection and Degradation of Stalled Nascent Chains via Ribosome-Associated Quality Control.

Stalled protein synthesis produces defective nascent chains that can harm cells. In response, cells degrade these nascent chains via a process called ribosome-associated quality control (RQC). Here, we review the irregularities in the translation process that cause ribosomes to stall as well as how cells use RQC to detect stalled ribosomes, ubiquitylate their tethered nascent chains, and deliver the ubiquitylated nascent chains to the proteasome. We additionally summarize how cells respond to RQC failure.

Alanine Tails Signal Proteolysis in Bacterial Ribosome-Associated Quality Control.

In ribosome-associated quality control (RQC), Rqc2/NEMF closely supports the E3 ligase Ltn1/listerin in promoting ubiquitylation and degradation of aberrant nascent-chains obstructing large (60S) ribosomal subunits-products of ribosome stalling during translation. However, while Ltn1 is eukaryote-specific, Rqc2 homologs are also found in bacteria and archaea; whether prokaryotic Rqc2 has an RQC-related function has remained unknown. Here, we show that, as in eukaryotes, a bacterial Rqc2 homolog (RqcH) recognizes obstructed 50S subunits and promotes nascent-chain proteolysis. Unexpectedly, RqcH marks nascent-chains for degradation in a direct manner, by appending C-terminal poly-alanine tails that act as degrons recognized by the ClpXP protease. Furthermore, RqcH acts redundantly with tmRNA/ssrA and protects cells against translational and environmental stresses. Our results uncover a proteolytic-tagging mechanism with implications toward the function of related modifications in eukaryotes and suggest that RQC was already active in the last universal common ancestor (LUCA) to help cope with incomplete translation.

Cytosolic Protein Vms1 Links Ribosome Quality Control to Mitochondrial and Cellular Homeostasis.

Eukaryotic cells have evolved extensive protein quality-control mechanisms to remove faulty translation products. Here, we show that yeast cells continually produce faulty mitochondrial polypeptides that stall on the ribosome during translation but are imported into the mitochondria. The cytosolic protein Vms1, together with the E3 ligase Ltn1, protects against the mitochondrial toxicity of these proteins and maintains cell viability under respiratory conditions. In the absence of these factors, stalled polypeptides aggregate after import and sequester critical mitochondrial chaperone and translation machinery. Aggregation depends on C-terminal alanyl/threonyl sequences (CAT-tails) that are attached to stalled polypeptides on 60S ribosomes by Rqc2. Vms1 binds to 60S ribosomes at the mitochondrial surface and antagonizes Rqc2, thereby facilitating import, impeding aggregation, and directing aberrant polypeptides to intra-mitochondrial quality control. Vms1 is a key component of a rescue pathway for ribosome-stalled mitochondrial polypeptides that are inaccessible to ubiquitylation due to coupling of translation and translocation.

Ribosome-associated quality-control mechanisms from bacteria to humans.

Ribosome-associated quality-control (RQC) surveys incomplete nascent polypeptides produced by interrupted translation. Central players in RQC are the human ribosome- and tRNA-binding protein, NEMF, and its orthologs, yeast Rqc2 and bacterial RqcH, which sense large ribosomal subunits obstructed with nascent chains and then promote nascent-chain proteolysis. In canonical eukaryotic RQC, NEMF stabilizes the LTN1/Listerin E3 ligase binding to obstructed ribosomal subunits for nascent-chain ubiquitylation. Furthermore, NEMF orthologs across evolution modify nascent chains by mediating C-terminal, untemplated polypeptide elongation. In eukaryotes, this process exposes ribosome-buried nascent-chain lysines, the ubiquitin acceptor sites, to LTN1. Remarkably, in both bacteria and eukaryotes, C-terminal tails also have an extra-ribosomal function as degrons. Here, we discuss recent findings on RQC mechanisms and briefly review how ribosomal stalling is sensed upstream of RQC, including via ribosome collisions, from an evolutionary perspective. Because RQC defects impair cellular fitness and cause neurodegeneration, this knowledge provides a framework for pathway-related biology and disease studies.

MISTERMINATE Mechanistically Links Mitochondrial Dysfunction with Proteostasis Failure.

Mitochondrial dysfunction and proteostasis failure frequently coexist as hallmarks of neurodegenerative disease. How these pathologies are related is not well understood. Here, we describe a phenomenon termed MISTERMINATE (mitochondrial-stress-induced translational termination impairment and protein carboxyl terminal extension), which mechanistically links mitochondrial dysfunction with proteostasis failure. We show that mitochondrial dysfunction impairs translational termination of nuclear-encoded mitochondrial mRNAs, including complex-I 30kD subunit (C-I30) mRNA, occurring on the mitochondrial surface in Drosophila and mammalian cells. Ribosomes stalled at the normal stop codon continue to add to the C terminus of C-I30 certain amino acids non-coded by mRNA template. C-terminally extended C-I30 is toxic when assembled into C-I and forms aggregates in the cytosol. Enhancing co-translational quality control prevents C-I30 C-terminal extension and rescues mitochondrial and neuromuscular degeneration in a Parkinson's disease model. These findings emphasize the importance of efficient translation termination and reveal unexpected link between mitochondrial health and proteome homeostasis mediated by MISTERMINATE.

The genome of the black-footed cat: Revealing a rich natural history and urgent conservation priorities for small felids.

Habitat degradation and loss of genetic diversity are common threats faced by almost all of today's wild cats. Big cats, such as tigers and lions, are of great concern and have received considerable conservation attention through policies and international actions. However, knowledge of and conservation actions for small wild cats are lagging considerably behind. The black-footed cat, Felis nigripes, one of the smallest felid species, is experiencing increasing threats with a rapid reduction in population size. However, there is a lack of genetic information to assist in developing effective conservation actions. A de novo assembly of a high-quality chromosome-level reference genome of the black-footed cat was made, and comparative genomics and population genomics analyses were carried out. These analyses revealed that the most significant genetic changes in the evolution of the black-footed cat are the rapid evolution of sensory and metabolic-related genes, reflecting genetic adaptations to its characteristic nocturnal hunting and a high metabolic rate. Genomes of the black-footed cat exhibit a high level of inbreeding, especially for signals of recent inbreeding events, which suggest that they may have experienced severe genetic isolation caused by habitat fragmentation. More importantly, inbreeding associated with two deleterious mutated genes may exacerbate the risk of amyloidosis, the dominant disease that causes mortality of about 70% of captive individuals. Our research provides comprehensive documentation of the evolutionary history of the black-footed cat and suggests that there is an urgent need to investigate genomic variations of small felids worldwide to support effective conservation actions.

Three prime repair exonuclease 1 preferentially degrades the integration-incompetent HIV-1 DNA through favorable kinetics, thermodynamic, structural, and conformational properties.

HIV-1 integration into the human genome is dependent on 3'-processing of the viral DNA. Recently, we reported that the cellular Three Prime Repair Exonuclease 1 (TREX1) enhances HIV-1 integration by degrading the unprocessed viral DNA, while the integration-competent 3'-processed DNA remained resistant. Here, we describe the mechanism by which the 3'-processed HIV-1 DNA resists TREX1-mediated degradation. Our kinetic studies revealed that the rate of cleavage (kcat) of the 3'-processed DNA was significantly lower (approximately 2-2.5-fold) than the unprocessed HIV-1 DNA by TREX1. The kcat values of human TREX1 for the processed U5 and U3 DNA substrates were 3.8 s-1 and 4.5 s-1, respectively. In contrast, the unprocessed U5 and U3 substrates were cleaved at 10.2 s-1 and 9.8 s-1, respectively. The efficiency of degradation (kcat/Km) of the 3'-processed DNA (U5-70.2 and U3-28.05 pM-1s-1) was also significantly lower than the unprocessed DNA (U5-103.1 and U3-65.3 pM-1s-1). Furthermore, the binding affinity (Kd) of TREX1 was markedly lower (∼2-fold) for the 3'-processed DNA than the unprocessed DNA. Molecular docking and dynamics studies revealed distinct conformational binding modes of TREX1 with the 3'-processed and unprocessed HIV-1 DNA. Particularly, the unprocessed DNA was favorably positioned in the active site with polar interactions with the catalytic residues of TREX1. Additionally, a stable complex was formed between TREX1 and the unprocessed DNA compared the 3'-processed DNA. These results pinpoint the mechanism by which TREX1 preferentially degrades the integration-incompetent HIV-1 DNA and reveal the unique structural and conformational properties of the integration-competent 3'-processed HIV-1 DNA.

The SARS-CoV-2 Spike is a virulence determinant and plays a major role on the attenuated phenotype of Omicron virus in a feline model of infection.

The role of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron BA.1 Spike (S) on disease pathogenesis was investigated. For this, we generated recombinant viruses harboring the S D614G mutation (rWA1-D614G) and the Omicron BA.1 S gene (rWA1-Omi-S) in the backbone of the ancestral SARS-CoV-2 WA1 strain genome. The recombinant viruses were characterized in vitro and in vivo. Viral entry, cell-cell fusion, plaque size, and the replication kinetics of the rWA1-Omi-S virus were markedly impaired when compared to the rWA1-D614G virus, demonstrating a lower fusogenicity and ability to spread cell-to-cell of rWA1-Omi-S. To assess the contribution of the Omicron BA.1 S protein to SARS-CoV-2 pathogenesis, the pathogenicity of rWA1-D614G and rWA1-Omi-S viruses was compared in a feline model. While the rWA1-D614G-inoculated cats were lethargic and showed increased body temperatures on days 2 and 3 post-infection (pi), rWA1-Omi-S-inoculated cats remained subclinical and gained weight throughout the 14-day experimental period. Animals inoculated with rWA1-D614G presented higher infectious virus shedding in nasal secretions, when compared to rWA1-Omi-S-inoculated animals. In addition, tissue replication of the rWA1-Omi-S was markedly reduced compared to the rWA1-D614G, as evidenced by lower viral load in tissues on days 3 and 5 pi. Histologic examination of the nasal turbinate and lungs revealed intense inflammatory infiltration in rWA1-D614G-inoculated animals, whereas rWA1-Omi-S-inoculated cats presented only mild to modest inflammation. Together, these results demonstrate that the S protein is a major virulence determinant for SARS-CoV-2 playing a major role for the attenuated phenotype of the Omicron virus. IMPORTANCE: We have demonstrated that the Omicron BA.1.1 variant presents lower pathogenicity when compared to D614G (B.1) lineage in a feline model of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. There are over 50 mutations across the Omicron genome, of which more than two-thirds are present in the Spike (S) protein. To assess the role of the Omicron BA.1 S on virus pathogenesis, recombinant viruses harboring the S D614G mutation (rWA1-D614G) and the Omicron BA.1 Spike gene (rWA1-Omi-S) in the backbone of the ancestral SARS-CoV-2 WA1 were generated. While the Omicron BA.1 S promoted early entry into cells, it led to impaired fusogenic activity and cell-cell spread. Infection studies with the recombinant viruses in a relevant naturally susceptible feline model of SARS-CoV-2 infection here revealed an attenuated phenotype of rWA1-Omi-S, demonstrating that the Omi-S is a major determinant of the attenuated disease phenotype of Omicron strains.

Sporotrichosis Cluster in Domestic Cats and Veterinary Technician, Kansas, USA, 2022.

We describe a feline sporotrichosis cluster and zoonotic transmission between one of the affected cats and a technician at a veterinary clinic in Kansas, USA. Increased awareness of sporotrichosis and the potential for zoonotic transmission could help veterinary professionals manage feline cases and take precautions to prevent human acquisition.

Morphological evaluation of the feline placenta correlates with gene expression of vascular growth factors and receptors†.

Placental angiogenesis is critical for normal development. Angiogenic factors and their receptors are key regulators of this process. Dysregulated placental vascular development is associated with pregnancy complications. Despite their importance, vascular growth factor expression has not been thoroughly correlated with placental morphologic development across gestation in cats. We postulate that changes in placental vessel morphology can be appreciated as consequences of dynamic expression of angiogenic signaling agents. Here, we characterized changes in placental morphology alongside expression analysis of angiogenic factor splice variants and receptors throughout pregnancy in domestic shorthair cats. We observed increased vascular and lamellar density in the lamellar zone during mid-pregnancy. Immunohistochemical analysis localized the vascular endothelial growth factor A (VEGF-A) receptor KDR to endothelial cells of the maternal and fetal microvasculatures. PlGF and its principal receptor Flt-1 were localized to the trophoblasts and fetal vasculature. VEGF-A was found in trophoblast cells and associated with endothelial cells. We detected expression of two Plgf splice variants and four Vegf-a variants. Quantitative real-time polymerase chain reaction analysis showed upregulation of mRNAs encoding pan Vegf-a and all Vegf-a splice forms at gestational days 30-35. Vegf-A showed a marked relative increase in expression during mid-pregnancy, consistent with the pro-angiogenic changes seen in the lamellar zone at days 30-35. Flt-1 was upregulated during late pregnancy. Plgf variants showed stable expression during the first two-thirds of pregnancy, followed by a marked increase toward term. These findings revealed specific spatiotemporal expression patterns of VEGF-A family members consistent with pivotal roles during normal placental development.

Rhinoconjunctivitis severity induced by cat exposure influences early and late asthmatic responses: Evidence from an environmental exposure chamber.

BACKGROUND: The impact of allergic rhinoconjunctivitis on the early (EAR) and late asthmatic response (LAR) has yet to be assessed during optimal allergen exposure conditions. OBJECTIVE: We aimed to assess predictive factors of the EAR and LAR and to evaluate the relation between rhinitis, conjunctivitis and asthma induced by cat allergen exposure in an environmental exposure chamber (EEC). METHODS: Data from two cohort studies involving asthmatic patients with cat allergy who performed a cat allergen exposure challenge in ALYATEC EEC were analysed. Spirometry, visual analogue scale (VAS) for asthma, VAS for rhinitis, Total Nasal Symptoms Score, Total Ocular Symptoms Score (TOSS), Rhinoconjunctivitis Total Symptoms Score and Abelson score were used to assess asthma, rhinitis and conjunctivitis during and after exposure. RESULTS: An EAR occurred in 65.1% of patients, 32.1% of whom had a LAR. The diameter of the prick test to cat allergens and non-specific bronchial hypersensitivity level were independent risk factors for EAR (p < .05). No independent risk factors for LAR were identified. Rhinoconjunctivitis severity during exposure correlated with the asthma VAS during EAR and LAR (p < .05). Allergen exposure time needed to trigger an EAR correlated with the Abelson score during exposure (p < .05). The asthma VAS and TOSS during exposure correlated with faster LAR occurrence (p < .05). CONCLUSION: Prick test size and non-specific bronchial hypersensitivity level were confirmed as independent predictive factors of EAR during allergen exposure in an EEC. This study demonstrated the relation between the severity of rhinitis, conjunctivitis and asthma induced by allergen exposure for both EAR and LAR.

Human transmission and outbreaks of feline-like G6 rotavirus revealed with whole-genome analysis of G6P[9] feline rotavirus.

Group A rotaviruses (RVAs) are generally highly species-specific; however, some strains infect across species. Feline RVAs sporadically infect humans, causing gastroenteritis. In 2012 and 2013, rectal swab samples were collected from 61 asymptomatic shelter cats at a public health center in Mie Prefecture, Japan, to investigate the presence of RVA and any association with human infections. The analysis identified G6P[9] strains in three cats and G3P[9] strains in two cats, although no feline RVA sequence data were available for the former. A whole-genome analysis of these G6P[9] strains identified the genotype constellation G6-P[9]-I2-R2-C2-M2-A3-N2-T3-E3-H3. The nucleotide identity among these G6P[9] strains exceeded 99.5% across all 11 gene segments, indicating the circulation of this G6P[9] strain among cats. Notably, strain RVA/Human-wt/JPN/KF17/2010/G6P[9], previously detected in a 3-year-old child with gastroenteritis, shares high nucleotide identity (>98%) with Mie20120017f, the representative G6P[9] strain in this study, across all 11 gene segments, confirming feline RVA infection and symptomatic presentation in this child. The VP7 gene of strain Mie20120017f also shares high nucleotide identity with other sporadically reported G6 RVA strains in humans. This suggests that feline-origin G6 strains as the probable source of these sporadic G6 RVA strains causing gastroenteritis in humans globally. Moreover, a feline-like human G6P[8] strain circulating in Brazil in 2022 was identified, emphasizing the importance of ongoing surveillance to monitor potential global human outbreaks of RVA.

Comprehensive genomic profiling from C-CAT database unveiled over 80% presence of oncogenic drivers in anaplastic thyroid carcinoma including BRAF, RAS family, NF1, and FGFR1.

OBJECTIVE: Anaplastic thyroid carcinoma (ATC) is considered a very aggressive carcinoma and has been difficult to treat with therapeutic strategies. This study examines the landscape of genomic alteration in ATC, including the BRAF V600E mutation, and its clinical implications. DESIGN, PATIENTS AND MESUREMENT: A retrospective observational study was conducted using collected at the Center for Cancer Genomics and Advanced Therapeutics (C-CAT) in Japan, utilizing comprehensive genomic profiling data from 102 ATC cases. Additionally, AACR-GENIE data from 267 cases were analysed for validation. Statistical methods, including the conditional Kendall tau statistic and χ2 tests, were employed for survival analysis and gene mutation comparisons. RESULTS: Among 102 ATCs, BRAF, RAS, and other driver mutations were found in 83 cases (81.2%). The prevalence of BRAF V600E mutations was as high as 60%. Co-mutation analysis identified different genomic profiles in the BRAF, RAS, and wild-type groups. Despite the diverse molecular backgrounds, no significant differences in clinical variables and overall survival were observed. The analysis considering left-side amputation suggested that RAS mutations had a poorer prognosis. In the BRAF/RAS wild-type group, FGFR1 and NF1 were identified as driver mutations, with an accumulation of copy number variations and less TERT promoter mutations. This molecular subgrouping was also supported by the AACR-GENIE data. CONCLUSIONS: Comprehensive genomic analysis of ATC in Japan revealed distinct molecular subgroups, highlighting the importance of BRAF V600E mutations, particularly V600E, as potential therapeutic targets and suggest the relevance of tailor-made therapeutic strategies based on genomic profiling.

Increasing Prevalence of Sensitization to Cat/Dog Allergens in the COVID-19 Pandemic.

INTRODUCTION: Cat and dog allergens are common indoor triggers for respiratory allergies such as allergic rhinitis and asthma. This study aims to evaluate the prevalence of cat and dog allergies in adults and analyze changes during the COVID-19 pandemic. METHODS: We retrospectively analyzed the medical records of 8,102 patients who visited an allergy clinic and underwent skin prick testing (SPT) from March 2018 to March 2022: 2 years before and 2 years during the pandemic. Demographic information, clinical attributes, and laboratory results were examined based on patient records. RESULTS: Of 8,102 SPTs performed, 400 (4.9%) were sensitized to cat allergen and 289 (3.6%) to dog allergen. Allergic rhinitis was the predominant clinical diagnosis in both groups. Of the 400 subjects exposed to cats, 240 (60%) experienced allergic symptoms, while of the 289 subjects exposed to dogs, 65 (22.5%) experienced allergic symptoms during exposure. Within the cat-sensitized group, anaphylaxis was observed in 5 patients (1.3%), while no cases of anaphylaxis were reported in the dog-sensitized group. Compared to the pre-pandemic period, patients presenting during the pandemic had higher rates of cat and dog sensitization (5.7% vs. 4.1%; p < 0.05, 5.2% vs. 1.7%; p < 0.05). CONCLUSION: During the COVID-19 pandemic, there was an increase in cat and dog allergies among adults. Increased exposure to pet antigens, both directly and indirectly, has resulted in more people becoming sensitized to cats or dogs.

Cat eye syndrome: Clinical, cytogenetics and familial findings in a large cohort of 43 patients highlighting the importance of congenital heart disease and inherited cases.

Cat Eye Syndrome (CES) is a rare genetic disease caused by the presence of a small supernumerary marker chromosome derived from chromosome 22, which results in a partial tetrasomy of 22p-22q11.21. CES is classically defined by association of iris coloboma, anal atresia, and preauricular tags or pits, with high clinical and genetic heterogeneity. We conducted an international retrospective study of patients carrying genomic gain in the 22q11.21 chromosomal region upstream from LCR22-A identified using FISH, MLPA, and/or array-CGH. We report a cohort of 43 CES cases. We highlight that the clinical triad represents no more than 50% of cases. However, only 16% of CES patients presented with the three signs of the triad and 9% not present any of these three signs. We also highlight the importance of other impairments: cardiac anomalies are one of the major signs of CES (51% of cases), and high frequency of intellectual disability (47%). Ocular motility defects (45%), abdominal malformations (44%), ophthalmologic malformations (35%), and genitourinary tract defects (32%) are other frequent clinical features. We observed that sSMC is the most frequent chromosomal anomaly (91%) and we highlight the high prevalence of mosaic cases (40%) and the unexpectedly high prevalence of parental transmission of sSMC (23%). Most often, the transmitting parent has mild or absent features and carries the mosaic marker at a very low rate (<10%). These data allow us to better delineate the clinical phenotype associated with CES, which must be taken into account in the cytogenetic testing for this syndrome. These findings draw attention to the need for genetic counseling and the risk of recurrence.

Analysis of PROS1 mutations and clinical characteristics in three Chinese families with hereditary protein S deficiency.

We report three heterozygous PROS1 mutations that caused type I protein S deficiency in three unrelated Chinese families. We measured protein S activity and antigen levels for all participants, screened them for mutations in the PROS1 gene. And we employed the calibrated automated thrombin generation (CAT) method to investigate thrombin generation. Numerous bioinformatics tools were utilized to analyze the conservation, pathogenicity of mutation, and spatial structure of the protein S. Phenotyping analysis indicated that all three probands exhibited simultaneous reduced levels of PS:A, TPS:Ag, and FPS:Ag. Genetic testing revealed that proband A harbored a heterozygous c.458_458delA (p.Lys153Serfs*6) mutation in exon 5, proband B carried a heterozygous c.1687C>T (p.Gln563stop) mutation in exon 14, and proband C exhibited a heterozygous c.200A>C (p.Glu67Ala) mutation in exon 2. Bioinformatic analysis predicted that the p.Lys153Serfs*6 frameshift mutation and the p.Gln563stop nonsense mutation in the protein S were classified as "disease-causing." The identification of the novel mutation p.Lys153Serfs*6 in PROS1 enriches the Human Genome Database. Our research suggests that these three mutations (p.Lys153Serfs*6, p.Gln563stop, and p.Glu67Ala) are possibly responsible for the decreased level of protein S in the three families. Furthermore, the evidence also supports the notion that individuals who are asymptomatic but have a family history of PSD can benefit from genetic analysis of the PROS1 gene.

Advancing diagnostic precision: Unveiling sensitization relationships between cat, dog, and horse allergen molecules.

BACKGROUND: Recent advancements in molecular diagnostics have unveiled a multitude of allergen molecules (AMs) associated with animal sensitizations, revealing significant cross- and co-sensitization patterns among these seemingly distinct allergens. METHOD: We investigated the sensitization profiles of 120 children, sensitized to at least one of the 14 AMs from cat, dog, or horse using the Alex test, employing correlations and hierarchical clusters to explore relationship between sensitizations. RESULTS: Sensitizations to Fel d 1, Can f 4/5, and Equ c 4 differ from other cat, dog, and horse AM sensitizations, suggesting they may represent genuine sensitizations for their respective animals. High correlations were observed among various AMs, including lipocalins (Can f 1/2/6, Fel d 4/7, and Equ c 1), serum albumins (Fel d 2, Can f 3, and Equ c 3), and uteroglobins (Fel d 1 and Can f_Fd1). Hierarchical clustering of sensitizations identified two similarity clusters and one dissimilarity cluster, providing an estimation of the likelihood of cross-reactivity. Additionally, our method facilitated speculation regarding cross-, co-, or genuine sensitization. Moreover, we noted a potential increase in the number and level of sensitized animal AMs concurrent with increased sensitization to other aeroallergens with advancing age. No significant difference was detected for the presence or absence of various types of allergic comorbidities. CONCLUSION: Correlations and hierarchical clustering can unveil the extent and magnitude of cross-, co-, and genuine sensitization relationships among animal AMs. These insights can be leveraged to enhance artificial intelligence algorithms, improving diagnostic accuracy through the integration of other measures of sensitization.

Unmasking Bartonella henselae infection in the shadows of long COVID thanks to clinical metagenomics.

The diagnosis of long COVID often relies on symptoms post-COVID-19, occasionally lacking biological evidence. This case study illustrates how investigating long COVID uncovered an underlying bartonellosis through clinical metagenomics. Following mild COVID-19, a 26-year-old woman experienced persistent symptoms during 5 months, including axillary adenopathy. Pathological examination, 16 S rRNA PCR, and clinical metagenomic analysis were done on an adenopathy biopsy. The latter revealed Bartonella henselae DNA and RNA. Treatment with clarithromycin improved symptoms. This case underscores the relevance of clinical metagenomics in diagnosing hidden infections. Post-COVID symptoms warrant thorough investigation, and bartonellosis should be considered in polyadenopathy cases, regardless of a recent history of cat or flea exposures.

Revealing microbial community characteristics in healthy human, cat and canine salivas and looking for species-specific microbes.

As two kinds of increasingly popular pets, the saliva of cat or canine is most likely to be left at the crime scene compared with the common types of body fluids in forensics. Accurately identifying the species of saliva samples found at the crime scene involving pets will help the investigators find available testing materials, reduce the consumption of reagents and save the investigative time of the case. Therefore, it is necessary to explore the characteristics and differences of saliva microbiomes of cat, canine and human. In this study, 16S rRNA gene amplicon sequencing technology was used to reveal microbial communities of saliva samples of healthy human, cat, and canine. Alpha diversity analyses indicated that canine saliva demonstrated the highest microbial diversity, followed by cat saliva, whereas human saliva microbial diversity was the lowest. The saliva samples of the three species all had their own unique microbial community compositions, and the dominant phyla of canine and cat salivas were Proteobacteria and Bacteroidete, while the dominant phyla of human saliva were Firmicutes and Proteobacteria. There was no significant statistical difference in the salivary microbiota obtained by the two collection methods (cotton swab and liquid saliva). The gender of cats and canines might have no effect on the salivary microbiota, but the different breeds had an impact on their saliva microbiomes. Principal coordinates analysis, non-metric multidimensional scaling analysis and random forest analysis all indicated significant differences in microbial community structures among the three species, allowing inference on the species sources of saliva samples by microbiome method. Differential microbial biomarkers for the salivas of three species were screened out using a variety of bioinformatics analyses, and the results demonstrated that Prevotella melaninogenica, Veillonella parvula, and Haemophilus parainfluenzae could be used as species-specific microbial biomarkers of human saliva. The detections of human species-specific microbes provide a potential method for determining human saliva.

Epidemiology and treatment of invasive Bartonella spp. infections in the United States.

OBJECTIVES: Bartonella spp., renowned for cat-scratch disease, has limited reports of dissemination. Tissue and blood cultures have limitations in detecting this fastidious pathogen. Molecular testing (polymerase chain reaction, PCR) and cell-free DNA have provided an avenue for diagnoses. This retrospective observational multicenter study describes the incidence of disseminated Bartonella spp. and treatment-related outcomes. METHODS: Inclusion criteria were diagnosis of bartonellosis via diagnosis code, serology testing of blood, polymerase chain reaction (PCR) of blood, 16/18S tests of blood or tissue, cultures of blood or tissue, or cell-free DNA of blood or tissue from January 1, 2014, through September 1, 2021. Exclusions were patients who did not receive treatment, insufficient data on treatment course, absence of dissemination, or retinitis as dissemination. RESULTS: Patients were primarily male (n = 25, 61.0%), white (n = 28, 68.3%), with mean age of 50 years (SD 14.4), and mean Charlson comorbidity index of 3.5 (SD 2.1). Diagnosis was primarily by serology (n = 34, 82.9%), with Bartonella henselae (n = 40, 97.6%) as the causative pathogen. Treatment was principally doxycycline with rifampin (n = 17, 41.5%). Treatment failure occurred in 16 (39.0%) patients, due to escalation of therapy during treatment (n = 5, 31.3%) or discontinuation of therapy due to an adverse event or tolerability (n = 5, 31.3%). CONCLUSIONS: In conclusion, this is the largest United States-based cohort of disseminated Bartonella spp. infections to date with a reported 39% treatment failure. This adds to literature supporting obtaining multiple diagnostic tests when Bartonella is suspected and describes treatment options.