Influência da velocidade de circulação do leite na adesão de Pseudomonas aeruginosa sobre aço inoxidável

A influência da velocidade de circulação do leite na adesão bacteriana de Pseudomonas aeruginosa foi avaliada em teste de uso simulado por meio de um modelo de circuito de processamento de leite. O circuito é composto por uma tubulação de aço inoxidável AISI 304, com 1,9 cm de diâmetro e 5,8 m de comprimento, além de um tanque de 25 L, utilizado como reservatório do produto e das soluções sanitizantes. O reservatório foi acoplado a uma bomba centrífuga de ½ HP, para impulsionar o alimento ou soluções de higienização pelo sistema equipado com cupons de prova em aço inoxidável nas formas cilíndrica, cotovelo 90º e T. As velocidades de circulação foram de 0,5, 1,0 e 1,5 m.s-1, correspondentes a fluxo turbulento com número de Reynolds de 14.000, 28.000 e 42.000, respectivamente. Quando se utilizou velocidade de 0,5 m.s-1, permaneceram aderidas à superfície 10,7% das células. Já nas velocidades e 1,0 e 1,5 m.s-1 as porcentagens de adesão foram de 5,36 e 4,9%, respectivamente, o que demonstra uma menor remoção de células aderidas à medida que o fluxo diminui, permitindo assim que mais células permaneçam aderidas na linha de produção, o que pode favorecer a formação de biofilmes

Epidemiological profile of Trypanosoma cruzi-infected mothers and live birth conditions in the state of Minas Gerais, Brazil

INTRODUCTION: The aim of this study was to assess the epidemiological characteristics of Trypanosoma cruzi-infected mothers and the live birth conditions of neonates. METHODS: A serological survey with IgG-specific tests was conducted using dried blood samples from newborn infants in the State of Minas Gerais. T. cruzi infection was confirmed in mothers through positive serology in two different tests, and infected mothers were required to have their infants serologically tested after the age of 6 months. The birth conditions of the neonates were obtained from the System of Information on Live Births database. RESULTS: The study included 407 children born to T. cruzi-infected mothers and 407 children born to uninfected mothers. The average age of seropositive mothers was 32 years (CI95% 31.3-32.6), which was greater than the average age of seronegative mothers - 25 years (CI95% 24.8-25.2). The mothers' level of education was higher among uninfected mothers (41% had 8 or more years of education, versus 22% between the infected mothers). Vaginal delivery was more frequent among infected mothers. There was no evidence of inter-group differences with respect to the child's sex, gestational age, birth weight or Appearance, pulse, grimace, activity and respiration (APGAR) scores at 1 and 5 minutes. Conclusions: The level of education and the greater number of previous pregnancies and cases of vaginal delivery reflect the lower socioeconomical conditions of the infected mothers. In the absence of vertical transmission, neonates had similar health status irrespective of the infection status of their mothers

Toxigenic status of staphylococcus aureus isolated from bovine raw milk and minas frescal cheese in brazil

International audienceA group of 291 Staphylococcus aureus isolates from mastitic cow's milk (n = 125), bulk tank milk (n = 96), and Minas frescal cheese (n = 70) were screened for staphylococcal enterotoxin (SE) genes (sea, seb, sec, sed see, seg, seh, sei, selj, and sell) and for the tst-1 gene encoding staphylococcal toxic shock syndrome toxin 1 by PCR assay. A total of 109 (37.5%) of the isolates were positive for at least one of these 11 genes, and 23 distinct genotypes of toxin genes were observed. Of the S. aureus isolates bearing SE genes, 17 (13.6%) were from mastitic cow's milk, 41 (41.7%) were from bulk tank milk, and 51(72.9%) were from Minas frescal cheese. The occurrence of exclusively more recently described SE genes (seg through sell) was considerably higher (87 of 109 PCR-positive strains) than that of classical SE genes (sea through see, 15 strains). The SE genes most commonly detected were seg and sei; they were found alone or in different combinations with other toxin genes, but in 60.8% of the cases they were codetected. No strain possessed see. The tst-1 gene was found in eight isolates but none from mastitic cow's milk. Macrorestriction analysis of chromosomal DNA from 89 S. aureus isolates positive for SE gene(s) was conducted with the enzyme SmaI. Fifty-five distinct pulsed-field gel electrophoresis patterns were found, demonstrating a lack of predominance of any specific clone. A second enzyme, ApaI, used for some isolates was less discriminating than SmaI. The high genotype diversity of potential toxigenic S. aureus strains found in this study, especially from Minas frescal cheese, suggests various sources of contamination. Efforts from the entire production chain are required to improve consumer safety