Loading...
10 results
Search Results
Now showing 1 - 10 of 10
- Study of Biological Hazards Present on the Surfaces of Selected Fruits and VegetablesPublication . Noronha, Lúcia; Castro, Ana; Ferreira, Vânia; Magalhães, Rui; Almeida, Gonçalo; Mena, Cristina; Silva, Joana; Teixeira, PaulaThis study evaluated the microbial load on the surface of fruits with rough and very pronounced textured peels, namely pineapples and melons (cantaloupe), and investigated the presence of foodborne pathogens in these products since they are usually eaten raw. Similarly, lettuce is one of the most common salad vegetables consumed raw in Portugal, it therefore being important to study the microbial status of lettuce leaves. Enumerations of aerobic mesophilic counts, Enterobacteriaceae, Escherichia coli and coagulase-positive staphylococci, as well as detection of Listeria monocytogenes and Salmonella spp., were performed for all samples. Only in melon samples were E. coli and coagulase-positive staphylococci not detected. Contamination with L. monocytogenes varied from 2.5% and 15% in pineapple/melon and lettuce samples, respectively. Salmonella spp. were not detected. All coagulase-positive staphylococci had similar characteristics and none exhibited multidrug resistance. L. monocytogenes isolates belonged to serogroups II (1/2c or 3c), or to serogroup IV (4b, 4d and 4e). None were found to be resistant to antibiotics commonly used in therapy of listeriosis.
- Chemical composition and antibacterial properties of stem and leaf extracts from Ginja cherry plantPublication . Castro, A.; Silva, N.; Silva, Joana; Teixeira, Paula
- Prevalence of staphylococcus aureus from nares and hands on health care professionals in a portuguese hospitalPublication . Castro, A.; Komora, N.; Ferreira, Vânia; Lira, A.; Mota, M.; Silva, Joana; Teixeira, PaulaAims: The main goal was to estimate the prevalence of methicillin-resistant Staphylococcus aureus on hands and in nose of health care professionals. Methods and Results: Detection of Staph. aureus on hands or in the nose of 169 individuals was performed. Nasal and hand carriage was found in 39 6 and in 8 9% respectively. About 17 2% of the individuals were carriers of methicillin-resistant Staph. aureus (MRSA) in the nose and 4 7% on hands. The majority of nasal MRSA were resistant to b-lactams, erythromycin and ciprofloxacin. All nasal MRSA were SCCmec type IV and Panton-Valentine leukocidin (PVL) negative. One MRSA isolated from hand was SCCmec type V. About 75 6% of MRSA isolates presented the same or closely related restriction patterns. Sixty per cent of Staph. aureus from hands and from noses from the same individual were the same strain. Conclusions: MRSA nasal carriage was high considering healthy health care professionals but in accordance with high level of MRSA infection in Portugal. Isolates recovered in this study seemed to be different from major clones previously isolated in other Portuguese hospitals. Significance and Impact of the Study: These findings may have implications on the knowledge of healthy health care workers as vehicles of MRSA infections among the community. Presence of several virulence factors may contribute to increased pathogenesis in case of infection.
- Prevalence, Antimicrobial Susceptibility and Virulence Factors Profile of Methicillin- resistant Staphylococcus aureus (MRSA) on Food in PortugalPublication . Castro, A.; Palhau, C.; Cunha, S.; Camarinha, J.; Silva, Joana; Teixeira, Paula
- Antimicrobial resistance profile of Staphylococcus aureus isolated from foodPublication . Castro, Ana; Palhau, Carla; Cunha, Sara; Camarinha, Sofia; Silva, Joana; Teixeira, Paula
- Staphylococcus aureus, a food pathogen: virulence factors and antibiotic resistancePublication . Castro, Ana; Silva, Joana; Teixeira, PaulaStaphylococcus aureus is an extraordinarily versatile pathogen responsible for staphylococcal food poisoning, hospital and community infections, as well as toxic shock syndrome. S. aureus is considered the most effective food-borne bacterial pathogen that has ever evolved. The S. aureus metagenome contains 10s of genes encoding staphylococcal enterotoxins, which are responsible for the clinical symptoms associated with staphylococcal food poisoning. S. aureus may be present in food products, being a potential vehicle for transmission. Antibiotics are widely used not only in humans but also in animal husbandry and other agricultural activities. The occurrence of multiresistant strains in food(s) has been increasing; contaminated food is considered an important vehicle for antimicrobial resistance. Methicillin-resistant S. aureus (MRSA) was first recognized in animal infections in 1972 in milk from mastitic cows in Belgium. Animal-associated MRSA infections in humans were first reported during 2003–05 in the Netherlands. Presently, it was reported that livestock-associated MRSA CC398 in pork identifies a potential pathway from farms to the wider population through retail pork. MRSA commonly carry enterotoxin genes but there has been only one report of food intoxication due to MRSA. Antibiotic resistance associated to enterotoxins genes made S. aureus an evolving threat.
- Phenotypic and genotypic characterization of Staphylococcus aureus isolated from food industry workersPublication . Santos, Carla; Meireles, Helena; Ramos, Bárbara; Castro, Ana; Silva, Joana; Teixeira, Paula
- Prevalence of some virulence factors in Staphylococcus aureus isolated from health care personnel: haemolysis and enterotoxigenic genes profilePublication . Castro, A.; Silva, N.; Silva, Joana; Teixeira, Paula
- Phenotypic and genotypic characterization of Staphylococcus aureus isolated from food industry workersPublication . Santos, Carla; Meireles, Helena; Ramos, Bárbara; Castro, Ana; Silva, Joana; Teixeira, Paula
- Food handlers as potential sources of dissemination of virulent strains of Staphylococcus aureus in the communityPublication . Castro, A.; Santos, C.; Meireles, H.; Silva, Joana; Teixeira, PaulaFood handlers may constitute a reservoir of virulent strains of Staphy-lococcus aureus and may be vehicles of their transmission to food.One hundred and sixty-two volunteers were assessed for the presence of S. aureuson the hands and in the nose. S. aureus was isolated by routine procedures, and theisolates were tested for susceptibility against a panel of nine antimicrobial agents.The isolates were further characterized by SmaI-PFGE profiling and the presence ofvirulence factors.Results: The prevalence of S. aureus was 19.8% in the nose and 11.1% on the hands;6.2% of the individuals carried S. aureus both in their noses and hands, and threeindividuals had the same strain (PFGE type) in the nose and on the hands. Although82% of the isolates were resistant to at least one antibiotic, none demonstrated thepresence of either mecA gene or resistance to oxacillin (none identified as MRSA).Sixty-eight percent of the isolates from the nose and hands possessed enterotoxingenes.This study revealed a high prevalence of antibiotic resistance and virulence deter-minants among the isolates, including not only classical and novel enterotoxin genesbut also major virulence factors such as tst. Potential dissemination of these strainsin the community is a matter of concern.© 2015 King Saud Bin Abdulaziz University for Health Sciences. Published by ElsevierLimited. All rights reserved