Percorrer por autor "Baptista, Alexandra Lameira"
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- Diversity and antimicrobial resistance profile of bacteria isolated from sheep mastitis and bulk-tank milk in the east-centre region of PortugalPublication . Pereira, Maria; Baptista, Alexandra Lameira; Rosário, Mariana; Cruz, Rita; Esteves, Fernando; Madanelo, João; Nóbrega, Carmen; Mega, Cristina; Garcia, C.; Coelho, Catarina; Arede dos Santos, Carla Sofia; Malva, Madalena; Vala Correia, Helena Maria; Ferreira, TiagoThe microbiological quality of milk reflects both udder health and the subsequent contamination that can occur through direct and indirect reservoirs. This study aimed to identify bacterial diversity in milk samples from ewes with mastitis and in bulk-tank milk, and to investigate their antibiotic susceptibility/resistance profiles. A total of 232 milk samples were analysed and 22 bacterial species were isolated, with Staphylococcus aureus (20.3%) and S. epidermidis (18.6%) as the dominant species. The diversity of bacterial species isolated from the bulk-tank was higher and included 44 species, dominated by E. coli (20.6%), S. aureus (7.8%) and Hafnia alvei (7.2%). Antimicrobial susceptibility testing was performed on 217 bacterial isolates. E. coli isolated from individual milk samples revealed high rates of resistance to penicillins and tetracyclines, whereas S. aureus revealed high rates of resistance to aminoglycosides, polymyxin, sulfonamides and tetracycline, maintaining high levels of susceptibility to third generation cephalosporins, lincosamides, some macrolides, penicillins, phenicols and pleuromutilins. The resistance profile of bacteria isolated from the bulktank milk was more concerning than that of the milk of ewe with mastitis. These results point to the need to implement structural improvements on farms and raise awareness about strengthening biosecurity, medical prophylaxis and control of access to veterinary medicines to improve milk quality and reduce the use of antibiotics.
- Molecular Screening of Sarcocystis spp. in Grazing Sheep (Ovis aries) and Shepherd Dogs (Canis lupus familiaris) from Central PortugalPublication . Gomes-Gonçalves, Sara; Figueiredo, Ricardo J.; Rodrigues, Soraia; Bento, Jaqueline T.; Santos-Silva, Sérgio; Almeida, Daniela; Cruz, Rita; Esteve, Fernando; Esteves, Fernando; Baptista, Alexandra Lameira; Pereira, Maria Aires; Cardoso, Luís; Mesquita, João R.Sarcocystis spp. are cyst-forming protozoan parasites with a global distribution that infect a wide range of domestic and wild animals, impacting both animal health and livestock productivity. In sheep, infections can cause clinical disease, reproductive losses, and economic damage, articularly when pathogenic species such as Sarcocystis tenella are involved. Grazing sheep, including breeds such as the Serra da Estrela from central Portugal, are at increased risk due to frequent contact with shepherd dogs, which serve as definitive hosts. Despite their significance, data on the occurrence and distribution of Sarcocystis spp. in Portuguese sheep remain limited. This study analyzed 179 samples collected in central Portugal during 2024, including 41 brain tissues and 88 blood samples from sheep, and 50 stool samples from shepherd dogs, using conventional PCR and bidirectional Sanger sequencing. Sarcocystis sp. closely related to S. tenella was detected exclusively in sheep brain tissue, with a prevalence of 4.9% (2/41; 95% CI: 0.60–16.53), while no parasite DNA was found in blood or dog samples. These results provide the first molecular confirmation of Sarcocystis spp. closely related to S. tenella in Portuguese sheep raised for human consumption and establish baseline data for future epidemiological surveillance and control strategies.