Ana Claudia Veiga de Castro

Characterization for enterotoxin production, virulence factors, and antibiotic susceptibility of Staphylococcus aureus isolates from various foods in Portugal

Staphylococcus aureus represents a public health challenge worldwide. The aim of this study was the characterization of different food isolates of S. aureus on the basis of their production of enterotoxins, hemolysins and resistance to antibiotics. A total of 148 coagulase-positive staphylococcal strains isolated from different food origins were identified to the species level. By multiplex PCR, 69% of the isolates were shown to be enterotoxigenic (SEs); the most common were sea seg, sea seg sei and seg sei. According to CLSI [CLSI, Clinical and Laboratory Standards Institute, 2007. Performance Standards for Antimicrobial Susceptibility Testing; Fifteenth Informational Supplement. CLSI document M100-S15. Clinical and Laboratory Standards Institute, Wayne, PA], 38% of the isolates were resistant to oxacillin (>or= 6 microg/mL; MRSA positives) but only 0.68% showed the presence of mecA gene. 70 and 73% of the S. aureus strains were resistant to beta-lactams, ampicillin and penicillin, respectively. The virulence pattern was demonstrated to be origin and strain dependent. These findings emphasise the need to prevent the presence of S. aureus strains and SEs production in foods.

Food handlers as potential sources of dissemination of virulent strains of Staphylococcus aureus in the community

UNLABELLED Food handlers may constitute a reservoir of virulent strains of Staphylococcus aureus and may be vehicles of their transmission to food. One hundred and sixty-two volunteers were assessed for the presence of S. aureus on the hands and in the nose. S. aureus was isolated by routine procedures, and the isolates were tested for susceptibility against a panel of nine antimicrobial agents. The isolates were further characterized by SmaI-PFGE profiling and the presence of virulence 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 three individuals had the same strain (PFGE type) in the nose and on the hands. Although 82% of the isolates were resistant to at least one antibiotic, none demonstrated the presence of either mecA gene or resistance to oxacillin (none identified as MRSA). Sixty-eight percent of the isolates from the nose and hands possessed enterotoxin genes. This study revealed a high prevalence of antibiotic resistance and virulence determinants among the isolates, including not only classical and novel enterotoxin genes but also major virulence factors such as tst. Potential dissemination of these strains in the community is a matter of concern.

Prevalence of Staphylococcus aureus from nares and hands on health care professionals in a Portuguese Hospital.

The main goal was to estimate the prevalence of methicillin‐resistant Staphylococcus aureus on hands and in nose of health care professionals.

Leituras e leitores de Richard Morse: a trajetória de um livro sobre a formação da metrópole paulista

De comunidade a metropole: a biografia de Sao Paulo, was first published in 1954 and then re published in 1970 as Formacao historica de Sao Paulo: de comunidade a metropole. Written by a young US researcher fascinated by Latin America, this material was originally submitted as his PhD thesis at Columbia University in 1952. Since then, Richard Morses (1922-2001) work has come a long way and is now considered a primary reference in the history of urban development of Sao Paulo. This article briefly recovers the readers response when Morses research was first published, and how it ensured the books importance in the Brazilian historiography. The aim is to draw a parallel trajectory of the book and its author - the young researcher at Columbia who became a professor of Latin American History at Yale - and to discuss the meanings regarding its importance in Sao Paulos historiography as well as its contribution to a better understanding of the city.

Staphylococcus aureus, a Food Pathogen: Virulence Factors and Antibiotic Resistance

Abstract Staphylococcus 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.

Virulence and resistance profile of Staphylococcus aureus isolated from food

Staphylococcus aureus is considered a global community and health care pathogen responsible for staphylococcal food poisoning. The aim of this study was to characterize several isolates of S. aureus recovered from different food products concerning enterotoxin genes and other virulence factors including antimicrobial resistance. In 2009, a total of 78 coagulase-positive staphylococci from 1454 food samples were identified to species level; 73 were confirmed as S. aureus. Of the S. aureus isolates 5.5% were resistant to oxacillin, 52.0% showed resistance to erythromycin, and 45.2% to tetracycline. Multidrug resistance was observed in 33.3% of the isolates (resistance to three or more antibiotics of different classes). SCCmec types IV and V were detected among methicillin-resistant S. aureus (MRSA). One MRSA isolate was pvl positive. The 52.0% of food isolates were shown to be enterotoxigenic; egc (63.0%), secbov (44.7%) were the main detected SEs. tst gene was also detected in food isolates. The present wo...