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Yersinia Spp. (yersinia + spp)

Distribution by Scientific Domains

Life Sciences	75%

Selected Abstracts

Occurrence of Staphylococcus and enteropathogens in soft cheese commercialized in the city of Rio de Janeiro, Brazil

JOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2002
V.S. Araújo
Aims: To investigate the presence of Staphylococcus aureus, enteropathogenic Escherichia coli (EPEC), Aeromonas spp. and Yersinia spp. in soft cheese commercialized in Rio de Janeiro, Brazil. Methods and Results: A total of 45 samples of cheese from three different brands marketed in Rio de Janeiro city were analysed for faecal coliform levels using the Most Probable Number (MPN) technique. The samples were also analysed using conventional methodology for the investigation of food-borne pathogens. High levels of faecal contamination were detected in 95·5% of cheese samples. Staphylococcus aureus was isolated from 20% of samples, of which 17·7% were above the limits allowed by Brazilian legislation. Aeromonas hydrophila and Aer. caviae were detected in 17·7% of the samples. Yersinia spp. were not found in this study. EPEC was isolated from 21·1% of the samples and the most frequently found serogroups were O127, followed by O55 and O26. Conclusions: Our results showed that 95·5% of cheese samples had high levels of faecal coliforms. The isolation of Staph. aureus, serogroups of EPEC and Aeromonas spp. suggested that the soft cheese commercialized in the city of Rio de Janeiro may represent a health risk for the consumers. Significance and Impact of the Study: These results suggest that soft cheese may act as an important vehicle of transmission for well-established pathogens. [source]

BEHAVIOR OF AVIRULENT YERSINIA PESTIS IN LIQUID WHOLE EGG AS AFFECTED BY STORAGE TEMPERATURE, ANTIMICROBIALS AND THERMAL PASTEURIZATION

JOURNAL OF FOOD SAFETY, Issue 3 2010
JOSHUA B. GURTLER
ABSTRACT Yersinia spp. are psychrotrophic bacteria capable of growth at temperatures as low as ,2C, known to contaminate shell eggs and liquid eggs in the U.S.A. and South America. A study was performed to determine the thermal sensitivity of avirulent Yersinia pestis in liquid whole egg (LWE), evaluate the growth pattern of the bacterium in LWE at temperatures of 4,22C and assess the ability of 10 antimicrobial compounds to inhibit the growth of attenuated Y. pestis in LWE. The estimated decimal reduction values of avirulent Y. pestis in LWE at 54C (D54) were 1.39,1.58 min, and D60 values were 13.8 and 11.4 s by the addition of 0 and 965 IU of nisin (MP Biomedicals, LLC, Solon, OH), respectively. Low molecular weight chitosan (0.5%) and an activated lactoperoxidase system (2.18 U/mL) were ineffective at inhibiting growth of Y. pestis, while 500 IU/mL of nisin inhibited populations by up to 1 log cfu/mL at 4, 10 and 15C when compared with the control. Allyl isothiocyanate, diacetyl, diethyl dicarbonate, ethylenediaminetetraacetic acid, methylparaben, monolaurin and benzoyl peroxide inhibited the growth of attenuated Y. pestis when added at high levels. PRACTICAL APPLICATIONS The genus Yersinia does not currently pose a problem in pasteurized liquid egg products, although it has been isolated from eggs in the U.S.A. and Argentina. Yersiniae, which are psychrotrophic bacteria, can grow at temperatures as low as ,2C; therefore, incidental or intentional contamination of liquid whole egg (LWE) with Yersinia spp. could result in multiplication to high populations, even when stored under refrigeration (ca. 4C). We have shown that avirulent Yersinia pestis is able to multiply to populations of >2, 5 and 8 log cfu/mL in LWE at 4C within 6, 14 and 26 days, respectively. This study provides information that will be helpful in determining thermal and nonthermal means of controlling yersiniae in LWE products. [source]

Modulation of phosphoinositide metabolism by pathogenic bacteria

CELLULAR MICROBIOLOGY, Issue 11 2006
Hubert Hilbi
Summary Phosphoinositide metabolism plays a pivotal role in the regulation of receptor-mediated signal transduction, actin remodelling and membrane dynamics. Phosphoinositides co-ordinate these processes by recruiting protein effectors to distinct cellular membranes in a time- and organelle-dependent manner. Intracellular bacterial pathogens interfere with phosphoinositide metabolism to direct their entry into eukaryotic cells, form replication-permissive vacuoles, modulate apoptosis, or trigger fluid secretion. Gram-negative pathogens such as Legionella pneumophila, Shigella flexneri, or Salmonella enterica employ secretion systems to invade host cells by ,pathogen-triggered phagocytosis' and thereby bypass a requirement for phosphatidylinositol 3-kinases [PI(3)Ks]. Contrarily, ,receptor-mediated phagocytosis' of Yersinia spp., Listeria monocytogenes and other pathogenic bacteria depends on PI(3)Ks. Secreted effector proteins have been found to directly bind to and modify host cell phosphoinositides, thus modulating phagocytosis and intracellular survival of the pathogens. These effectors include L. pneumophila proteins that specifically attach to phosphatidylinositol 4-phosphate [PI(4)P] on the Legionella -containing vacuole, and phosphoinositide phosphatases produced by S. flexneri, S. enterica or Mycobacterium tuberculosis. This review covers current knowledge about subversion of host cell phosphoinositide metabolism by intracellular bacterial pathogens with an emphasis on recently identified secreted effector proteins directly engaging phosphoinositides. [source]

Substrate recognition of type III secretion machines ,testing the RNA signal hypothesis

CELLULAR MICROBIOLOGY, Issue 9 2005
Joseph A. Sorg
Summary Secretion by the type III pathway of Gram-negative microbes transports polypeptides into the extracellular medium or into the cytoplasm of host cells during infection. In pathogenic Yersinia spp., type III machines recognize 14 different Yop protein substrates via discrete signals genetically encoded in 7,15 codons at the 5, portion of yop genes. Although the signals necessary and sufficient for substrate recognition of Yop proteins have been mapped, a clear mechanism on how proteins are recognized by the machinery and then initiated into the transport pathway has not yet emerged. As synonymous substitutions, mutations that alter mRNA sequence but not codon specificity, affect the function of some secretion signals, recent work with several different microbes tested the hypothesis of an RNA-encoded secretion signal for polypeptides that travel the type III pathway. This review summarizes experimental observations and mechanistic models for substrate recognition in this field. [source]