Biology subjects

Rebelo, A.

Publications and source records attributed to Rebelo, A..

5 recordsLinked to original sources

bioRxiv2024

Decoding Klebsiella pneumoniae in Poultry Chain: Unveiling Genetic Landscape, Antibiotic Resistance, and Biocide Tolerance in Non-Clinical Reservoirs

The rise of antibiotic resistance in the food chain is influenced by the use of antimicrobial agents, such as antibiotics, metals, and biocides, throughout the entire farm-to-fork continuum. Besides, non-clinical reservoirs potentially contribute to the transmission of critical pathogens such as multidrug-resistant (MDR) Klebsiella pneumoniae. However, limited knowledge exists about the population structure and genomic diversity of K. pneumoniae circulating in conventional poultry production. We conducted a comprehensive characterization of K. pneumoniae across the whole chicken production chain (flocks/environment/meat, 2019-2022), exploring factors beyond antibiotics, like copper and quaternary ammonium compounds (QACs). Clonal diversity and adaptive features of K. pneumoniae were characterized through cultural, molecular (FT-IR), and whole-genome-sequencing (WGS) approaches. All except one flock were positive for K. pneumoniae with a significant increase (p < 0.05) from early to pre-slaughter stages, most persisting in chicken meat batches. Colistin-resistant K. pneumoniae rates were low (4%), while most samples carried MDR strains (67%) and copper-tolerant isolates (63%; sil+pco clusters; MICCuSO4[≥]16mM), particularly at pre-slaughter. Benzalkonium chloride consistently exhibited activity in K. pneumoniae (MIC/MBC range=4-64mg/L) from diverse and representative strains independently of the presence/absence of genes linked to QACs tolerance. A polyclonal K. pneumoniae population, discriminated by FT-IR and WGS, included various lineages dispersed throughout the chickens lifecycle at the farm (ST29-KL124, ST11-KL106, ST15-KL19, ST1228-KL38), until the meat (ST1-KL19, ST11-KL111, ST6405-KL109, and ST6406-CG147-KL111), or over years (ST631-49 KL109, ST6651-KL107, ST6406-CG147-KL111). Notably, some lineages were identical to those from human clinical isolates. WGS also revealed F-type multireplicon plasmids carrying sil+pco (copper) co-located with qacE{Delta}1{+/-}qacF (QACs) and antibiotic resistance genes like those disseminated in humans. In conclusion, chicken farms and their derived meat are significant reservoirs for diverse K. pneumoniae clones enriched in antibiotic resistance and metal tolerance genes, some exhibiting genetic similarities with human clinical strains. Further research is imperative to unravel the factors influencing K. pneumoniae persistence and dissemination within poultry production, contributing to improved food safety risk management. This study underscores the significance of understanding the interplay between antimicrobial control strategies and non-clinical sources to effectively address the spread of antimicrobial resistance.

microbiology↗

bioRxiv2023

Sord deficient rats develop a motor-predominant peripheral neuropathy unveiling novel pathophysiological insights

Biallelic SORD mutations cause one of the most frequent forms of recessive hereditary neuropathy, estimated to affect approximately 10,000 patients in North America and Europe alone. Pathogenic SORD loss-of-function changes in the encoded enzyme sorbitol dehydrogenase result in abnormally high sorbitol levels in cells and serum. How sorbitol accumulation leads to peripheral neuropathy remains to be elucidated. A reproducible animal model for SORD neuropathy is essential to illuminate the pathogenesis of SORD deficiency and for preclinical studies of potential therapies. Therefore, we have generated a Sord knockout (KO), Sord-/-, Sprague Dawley rat, to model the human disease and to investigate the pathophysiology underlying SORD deficiency. We have characterized the phenotype in these rats with a battery of behavioral tests as well as biochemical, physiological, and comprehensive histological examinations. Sord-/- rats had remarkably increased levels of sorbitol in serum, cerebral spinal fluid (CSF), and peripheral nerve. Moreover, serum from Sord-/- rats contained significantly increased levels of neurofilament light chain, NfL, an established biomarker for axonal degeneration. Motor performance significantly declined in Sord-/- animals starting at [~]7 months of age. Gait analysis evaluated with video motion tracking confirmed abnormal gait patterns in the hindlimbs. Motor nerve conduction velocities of the tibial nerves were slowed. Light and electron microscopy of the peripheral nervous system revealed degenerating myelinated axons, de- and remyelinated axons, and a likely pathognomonic finding - enlarged "ballooned" myelin sheaths. These findings mainly affected myelinated motor axons; myelinated sensory axons were largely spared. In summary, Sord-/- rats develop a motor-predominant neuropathy that closely resembles the human phenotype. Our studies revealed novel significant aspects of SORD deficiency, and this model will lead to an improved understanding of the pathophysiology and the therapeutic options for SORD neuropathy.

neuroscience↗

bioRxiv2023

A common flanking variant is associated with enhanced meiotic stability of the FGF14-SCA27B locus

The factors driving initiation of pathological expansion of tandem repeats remain largely unknown. Here, we assessed the FGF14-SCA27B (GAA)*(TTC) repeat locus in 2,530 individuals by long-read and Sanger sequencing and identified a 5-flanking 17-bp deletion-insertion in 70.34% of alleles (3,463/4,923). This common sequence variation was present nearly exclusively on alleles with fewer than 30 GAA-pure repeats and was associated with enhanced meiotic stability of the repeat locus.

genetics↗

bioRxiv2023

From farm to fork: persistence of clinically-relevant multidrug-resistant and copper-tolerant Klebsiella pneumoniae long after colistin withdrawal in poultry production.

The concern of colistin-resistant bacteria in animal-food-environmental-human ecosystems prompted the poultry sector to implement colistin restrictions and explore alternative trace metals/copper feed supplementation. The impact of these strategies on the selection and persistence of colistin-resistant Klebsiella pneumoniae (Kp) in the whole poultry-production chain needs clarification. We assessed colistin-resistant and copper-tolerant Kp occurrence in chicken raised with inorganic and organic copper-formulas from one-day-old chicks to meat (7 farms/2019-2020), after long-term colistin withdrawal (>2-years). Clonal diversity and Kp adaptive features were characterized by cultural, molecular, and whole-genome-sequencing (WGS) approaches. Most chicken-flocks (75%) carried Kp at early+pre-slaughter stages, with a significant decrease (p<0.05) in meat batches (17%) and sporadic water/feed contamination. High rates (>50%) of colistin-resistant/mcr-negative Kp were observed among faecal samples, independently of feed. Most samples carried multidrug-resistant (90%) and copper-tolerant isolates (81%; pco+sil/MICCuSO4 [≥]16mM). WGS revealed accumulation of colistin resistance associated mutations and F-type multireplicon plasmids carrying antibiotic resistance and metal/copper-tolerance genes. The Kp population was polyclonal, with various lineages dispersed throughout poultry production. ST15-KL19, ST15-KL146 and ST392-KL27, and IncF plasmids were similar to those from global human clinical isolates, suggesting chicken-production as a reservoir/source of clinically-relevant Kp lineages and genes with potential risk to humans through food and/or environmental exposure. Despite long-term colistin ban limited mcr spread, it was ineffective in controlling colistin-resistant/mcr-negative Kp, regardless of feed. This study provides crucial insights into the persistence of clinically-relevant Kp in the poultry-production chain and highlights the need for continued surveillance and proactive food safety actions within a One-Health perspective. IMPORTANCEThe spread of bacteria resistant to last-resort antibiotics such as colistin throughout the food chain is a serious concern for public health. The poultry sector has responded by restricting colistin use and exploring alternative trace metals/copper feed supplements. However, it is unclear how and to which extent these changes impact the selection and persistence of clinically-relevant Klebsiella pneumoniae (Kp) throughout poultry chain. We found a high occurrence of copper-tolerant and colistin-resistant/mcr-negative Kp in chicken flocks, regardless of inorganic and organic copper-formulas and long-term colistin ban. Despite the high Kp diversity, the occurrence of identical lineages and plasmids across samples and/or clinical isolates suggests poultry as a potential source of human Kp exposure. This study highlights the need for continued surveillance and proactive farm-to-fork actions to mitigate the risks to public health, relevant for stakeholders involved in food industry and policymakers tasked with regulating food safety.

microbiology↗

bioRxiv2019

Intra-individual variability of sleep and nocturnal cardiac autonomic activity in elite female soccer players during an international tournament

PurposeThis study provides insights into the individual sleep patterns and nocturnal cardiac autonomic activity responses of elite female soccer players during an international tournament.\n\nMaterials and methodsTwenty elite female soccer players (aged 25.2{+/-}3.1 years) wore wrist actigraph units and heart rate (HR) monitors during night-sleep throughout 9 consecutive days (6 day-time training sessions [DT], 2 day-time matches [DM], and 1 evening-time match [EM]) of an international tournament. Training and match loads were monitored using the session-rating of perceived exertion (s-RPE) and wearable 18-Hz GPS (total distance covered [TD], training and match exposure time, and high-speed running [HSR]) to characterize training and match loads.\n\nResultsIndividually, s-RPE, TD, exposure time, and HSR during training sessions ranged from 20 to 680 arbitrary units (AU), 892 to 5176 m, 20 to 76 min, and 80 to 1140 m, respectively. During matches, s-RPE, TD, exposure time, and HSR ranged from 149 to 876 AU, 2236 to 11210 m, 20 to 98 min, and 629 to 3213 m, respectively. Individually, players slept less than recommended (<7 hours) on several days of the tournament, especially after EM (n=8; TST ranging between 6:00-6:54 h). Total sleep time coefficient of variation (CV) ranged between 3.1 and 18.7%. However, all players presented good sleep quality (i.e., sleep efficiency [≥]75%; individual range between: 75-98%) on each day of the tournament. Most of the players presented small fluctuations in nocturnal cardiac autonomic activity (individual nocturnal heart rate variability [HRV] ranged from 3.91-5.37 ms and HRV CV ranged from 2.8-9.0%), while two players presented higher HRV CV (11.5 and 11.7%; respectively).\n\nConclusionOverall, elite female soccer players seemed to be highly resilient to training and match schedules and loads during a 9 day international tournament.

physiology↗