微生物学技术

Listeria monocytogenes was discovered as a pathogen of animals and humans in the 1930s. As far as humans are concerned the organism was initially identified as a cause of abortion in early pregnancy, stillbirth, or of septicemia after an uneventful birth. Ecological surveys have demobstrat ...

The association of infection with consumption of contaminated water and foods, particularly poultry, is clearly established (1). Campylobacter food poisoning outbreaks occur either sporadically, affecting individuals and small groups suchs as families, or larger community ...

Salmonellosis is one of the most common, if not the most common infectious diseases transmitted by contaminated poultry foods (1,2). A critical goal in food processing plants and governmental control agencies is to prevent Salmonella contamination of food products and this prevention d ...

Lancefield’s group D is composed of Streptococcus equinus, S. faecalis, S. bovis, and S.faecium. S. avium (Q and D antigens). Group D is found in the intestinal tract of warm-blooded animals. The term “enterococcus” refers only to the species S. faecalis and S.faecium. The medium employed for enumerat ...

When the microbial flora invades food, two major problems arise. First is the pathogenicity of several microbes, and second are the changes on the food characteristics, such as contents of nutrients (hydrocarbons, vitamins, aminoacids, metals, etc.), bad smell, color and flavor, texture mo ...

Polymerase chain reaction (PCR) is a novel DNA amplification technique that has brought fundamental change to clinical diagnosis and rapid detection of food-borne pathogens. The technique needs little technical time and has a quick turnover. The results of PCR are accurate, sensitive, a ...

Mollicutes have restricted metabolic activities, and catabolism is primarily associated with ATP generation rather than the synthesis of metabolic precursors for anabolic metabolism (1). Nevertheless, the pathways of energy substrate metabolism and the range of substrates u ...

Mycoplasmas were first isolated from humans in 1937 (1), although it was not until 1951 (2) that selective media were used to identify mycoplasmas in the oropharynx. In 1962, an etiological link was established between what we now know to be Mycoplasma pneumoniae and cases of primary atypical pneu ...

Mycoplasmas are the smallest known free-living organisms, and adapted to a special mode of life as commensal organisms or opportunistic pathogens. Because of their small genome size, they have limited biosynthetic capacity, which means they lack many biochemical pathways found in the E ...

Mycoplasmas lack many of the biosynthetic pathways of higher organisms; consequently, their growth and survival depend on an external supply of a wide variety of nutrients. Because they are very fastidious in their nutritional requirements, a complex growth medium is required for their c ...

The existence of ureaplasmas, known formerly as T-strains, was first recognized in 1954 (1). Subsequently, it was found that these organisms possess the enzyme urease (2), a feature that made them unique among mollicutes and eventually led to their reclassification (3) within the new genus, Ure ...

The methods used for recovering mycoplasmas from birds are broadly similar to those described for other animals and for humans. Mycoplasmas are important causes of disease and loss of production in intensively reared poultry, particularly in those that are under environmental stress ( ...

Of the 30 or so mollicute species that have been isolated from small and large ruminants, only a handful have been shown to cause disease in their own right. This chapter will concentrate on methods for sampling, transporting, and isolating those pathogenic mycoplasmas, including Mycoplasma ...

Mollicutes include the smallest, free-living microorganisms. They are cell-wall-less bacteria, many of which produce disease in humans, animals, plants, or insects. Morphologically, mollicutes are extremely variable and pleomorphic, even in pure culture. Some organisms assu ...

To study the first stages of interactions between bacteria and mammalian host cells, it is necessary to locate the surface antigens involved in cytodhesion processes. The identification of a bacterial adhesin is normally based on experimental evidence of adherence inhibition in vitro ...

Membrane proteins of mycoplasmas assume particular significance in investigations of the pathogenesis of disease. They are involved in adhesion to, and probably in other interactions with, the cells of the target tissues of the host (1–5). They are frequently significant antigens in the i ...

Polyacrylamide gel electrophoresis (PAGE) of whole-cell proteins was first used for differentiation of mycoplasma species by Razin and Rottem (1) The method used was separation through 7.5% acrylamide gels containing 35% acetic acid and 5M urea. However, since the publication of Laemml ...

The expression of mycoplasma genes in Escherichia coli offers some interesting and unusual challenges compared to the expression of most other bacterial or eukaryotic cloned genes. For instance, the members of the genera Mycoplasma, Ureaplasma, and Spiroplasma all appear to utilize U ...

There are a range of methods that can be used to recover mycoplasmas from the infected sites of humans. The current standard method is culture on supplemented agar or broth media. The prolonged time for culture particularly for Mycoplasma pneumoniae, has necessitated a reliance by diagnostic ...

The expression of foreign genes in mollicutes has been difficult owing to inefficient transformation systems, and, until recently, by the lack of suitable cloning vectors. Few genes, excluding those associated with vector functions, have successfully been cloned and expressed in mol ...