Biology subjects

Magalhaes, M.

Publications and source records attributed to Magalhaes, M..

3 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

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↗

bioRxiv2021

A Novel Ex Vivo Peritoneal Model to Investigate Mechanisms of Peritoneal Metastasis in Gastric Adenocarcinoma

Peritoneal metastases (PM) portend limited survival in patients with Gastric Adenocarcinoma (GCa), and strategies to prevent and/or more effectively treat PM are needed. Existing models are limited in recapitulating key elements of the peritoneal metastatic cascade. To explore the underlying cellular and molecular mechanisms of PM, we have developed an ex vivo human peritoneal explant model. Fresh peritoneal tissue samples were obtained from patients undergoing abdominal surgery and suspended, mesothelial layer down but without direct contact, above a monolayer of red-fluorescent stained AGS human GCa cells for 24hrs, then washed and cultured for a further 3 days. Implantation and invasion of GCa cells within the explant were examined using real-time confocal fluorescence microscopy. Superficial implantation of AGS GCa cells within the mesothelial surface was readily detected, and colonies expanded over 3 days. To investigate the sensitivity of the model to altered GCa cellular implantation, we stably transfected AGS cells with E-Cadherin, restoring the E-Cadherin that they otherwise lack. This markedly suppressed implantation and invasion of AGS cells into the submesothelial mesenchymal layer. Here we show that this ex vivo human peritoneal explant model is responsive to manipulation of genetic factors that regulate peritoneal implantation and invasion by GCa cells, with reproducible results.

cancer biology↗