Browsing by Author "Martins da Costa, Paulo"
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- Caracterização genotípica e fenotípica de estirpes de Escherichia coli patogénicas, Salmonella spp. e Campylobacter spp. isoladas de aves em liberdade em Portugal continentalPublication . Batista, Rita; Saraiva, Margarida; Lopes, Teresa; Silveira, Leonor; Coelho, Anabela; Furtado, Rosália; Castro, Rita; Correia, Cristina Belo; Rodrigues, David; Henriques, Pedro; Lóio, Sara; Soeiro, Vanessa; Martins da Costa, Paulo; Oleastro, Mónica; Pista, ÂngelaAs aves são potenciais portadoras de microrganismos patogénicos que afetam os seres humanos, e podem ser disseminadoras de perigos no ambiente de produção primária de géneros alimentícios de origem vege- tal e animal. Este trabalho teve como objetivo avaliar a ocorrência, em fezes de aves em liberdade, em Portugal, de três bactérias zoonóticas causadoras de infeções no Homem. Para tal, foi avaliada a presença de Escherichia coli (E. coli), Salmonella spp. e Campylobacter spp. em 108 amostras individuais de fezes de aves e em uma amostra em pool de 50 amostras de fezes de gaivotas. Foi efetuada a caracterização fenotípica dos isolados (serotipagem e perfis de resistência a antibióticos) e dete- tados genes específicos associados à patogenicidade e à resistência a antimicrobianos, por PCR e/ou sequenciação total do genoma (WGS). Isolados de E. coli patogénicos, Salmonella spp. e Campylobacter spp. foram detetados em 8,9%, 2,8% e 9,9% das amostras, respetivamente. A resistência a antimicrobianos foi testada em 54 isolados de E. coli, tendo sido detetada em 14 (25,9%). Onze destes isolados revelaram a presença de fatores de virulência, E.coli patogénicos. Dez dos isolados de E. coli revelaram ser resistentes a múltiplos antimicrobianos (MDR) e sete eram produtores de β-lactamases de espectro alargado (ESBL). Re- lativamente aos isolados de Salmonella spp. (n=3) e Campylobacter spp. (n=9), apenas uma estirpe de Campylobacter jejuni foi identificada como MDR. A maioria dos serotipos e/ou Sequence Types (ST) identificados já tinham sido referenciados como associados a doença humana. Estes resultados mostram que as aves que fazem parte da fauna portuguesa podem ser portadoras de bactérias patogénicas capazes de causar do- ença humana, algumas delas resistentes a antimicrobianos críticos.
- Gulls in Porto Coastline as Reservoirs for Salmonella spp.: Findings from 2008 and 2023Publication . Rodrigues, Inês C.; Cristal, Ana Paula; Ribeiro-Almeida, Marisa; Silveira, Leonor; Prata, Joana C.; Simões, Roméo; Vaz-Pires, Paulo; Pista, Ângela; Martins da Costa, PauloGulls act as intermediaries in the exchange of microorganisms between the environment and human settlements, including Salmonella spp. This study assessed the antimicrobial resistance and molecular profiles of Salmonella spp. isolates obtained from fecal samples of gulls in the city of Porto, Portugal, in 2008 and 2023 and from water samples in 2023. Antimicrobial susceptibility profiling revealed an improvement in the prevalence (71% to 17%) and antimicrobial resistance between the two collection dates. Two isolate collections from both 2008 and 2023 underwent serotyping and whole-genome sequencing, revealing genotypic changes, including an increased frequency in the monophasic variant of S. Typhimurium. qacE was identified in 2008 and 2023 in both water and fecal samples, with most isolates exhibiting an MDR profile. The most frequently observed plasmid types were IncF in 2008 (23%), while IncQ1 predominated in 2023 (43%). Findings suggest that Salmonella spp. circulate between humans, animals, and the environment. However, the genetic heterogeneity among the isolates from the gulls' feces and the surface water may indicate a complex ecological and evolutionary dynamic shaped by changing conditions. The observed improvements are likely due to measures to reduce biological contamination and antimicrobial resistance. Nevertheless, additional strategies must be implemented to reduce the public health risk modeled by the dissemination of pathogens by gulls.
- Occurrence of Multidrug-Resistant Bacteria Resulting from the Selective Pressure of Antibiotics: A Comprehensive Analysis of ESBL K. pneumoniae and MRSP Isolated in a Dog with RhinorrheaPublication . Rodrigues, Inês C.; Ribeiro-Almeida, Marisa; Ribeiro, Jorge; Silveira, Leonor; Prata, Joana C.; Pista, Angela; Martins da Costa, PauloBecause of public health concerns, much greater scrutiny is now placed on antibiotic use in pets, especially for antimicrobial agents that have human analogs. Therefore, this study aimed to characterize the phenotypic and genotypic profiles of multidrug-resistant bacteria isolated from nasal swabs samples taken from a one-year-old male Serra da Estrela dog with rhinorrhea that was treated with amikacin. An extended-spectrum β-lactamases (ESBL) Klebsiella pneumoniae was isolated in the first sample taken from the left nasal cavity of the dog. Seven days later, methicillin-resistant (MRSP) Staphylococcus pseudintermedius was also isolated. Nevertheless, no alterations to the therapeutic protocol were performed. Once the inhibitory action of the antibiotic disappeared, the competitive advantage of the amikacin-resistant MRSP was lost, and only commensal flora was observed on both nasal cavities. The genotypic profile of extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae revealed the same characteristics and close relation to other strains, mainly from Estonia, Slovakia and Romania. Regarding MRSP isolates, although resistance to aminoglycosides was present in the first MRSP, the second isolate carried aac(6')-aph(2″), which enhanced its resistance to amikacin. However, the veterinary action was focused on the treatment of the primary agent (ESBL K. pneumoniae), and the antibiotic applied was according to its phenotypic profile, which may have led to the resolution of the infectious process. Therefore, this study highlights the importance of targeted therapy, proper clinical practice and laboratory-hospital communication to safeguard animal, human and environmental health.
- Unveiling a Listeria monocytogenes Outbreak in a Rabbit Farm: Clinical Manifestation, Antimicrobial Resistance, Genomic Insights and Environmental InvestigationPublication . Rodrigues, Inês C.; Ribeiro-Almeida, Marisa; Silveira, Leonor; Prata, Joana C.; de Carvalho, André Pinto; Roque, Carla; Gomes, João Paulo; Borges, Vítor; Pista, Ângela; Martins da Costa, PauloListeria monocytogenes poses a threat to both human and animal health. This work describes an L. monocytogenes outbreak in a Portuguese rabbit farm, detailing the isolates’ clinical manifestations, necropsy findings, and phenotypic and genomic profiles. Clinical signs, exclusively observed in does, included lethargy and reproductive signs. Post-mortem examination of does revealed splenomegaly, hepatomegaly with a reticular pattern, pulmonary congestion, and haemorrhagic lesions in the uterus, with thickening of the uterine wall and purulent greyish exudates. Positive L. monocytogenes samples were identified in fattening and maternity units across different samples, encompassing does and environmental samples. Core-genome Multi Locus Sequence Typing (cgMLST) analysis confirmed the outbreak, with the 16 sequenced isolates (lineage II, CC31, and ST325) clustering within a ≤2 allelic difference (AD) threshold. Antimicrobial susceptibility testing for five antibiotics revealed that 15 out of 19 outbreak isolates were resistant to sulfamethoxazole-trimethoprim (SXT). Concordantly, all SXT-resistant sequenced isolates were found to exclusively harbour a plasmid containing a trimethoprim-resistance gene (dfrD), along with loci linked to resistance to lincosamides (lnuG), macrolides (mphB), and polyether ionophores (NarAB operon). All sequenced outbreak isolates carried the antibiotic resistance-related genes tetM, fosX, lin, norB, lmrB, sul, and mprF. The outbreak cluster comprises isolates from does and the environment, which underscores the ubiquitous presence of L. monocytogenes and emphasizes the importance of biosecurity measures. Despite limited data on listeriosis in rabbit farming, this outbreak reveals its significant impact on animal welfare and production.