Cocci growth

If a negative peroxide test is obtained, then a gram stain should be performed on the second slide to determine whether the bacteria are gram-positive cocci. Growth in the BHI broth tube is transferred to (a) bile esculin agar (BEA), (b) another fresh tube of... 

Two studies compared the effect of rifaximin to that of neomycin and/or of rifampicin [72, 73] on the fecal flora in rats. In the first study [72] the antibiotic (1, 10, 30 and 100 mg/kg orally for 7 days) did inhibit both aerobic (especially coliforms and cocci) and anaerobic bacterial growth. Its activity was similar to that of neomycin and stronger than that of rifampicin. In the second investigation [73] the antibiotic effect on aerobic microorganisms was specifically investigated. Oral rifaximin treatment (50 mg/kg for 3 days) caused a marked reduction in the number of total aerobic bacteria and salmonellae, while neomycin led only to a decrease in salmonella counts, but did not cause statistically significant changes in the total aerobic bacterial population. 

Mycoplasmas may appear as filamentous forms, some of which may branch, indicating a culture in logarithmic growth or as cocci, which is typical of an aged... 

Since wine and beer are fermentation products, shelf life will be limited unless all yeast are removed. Unless beer is kept very cold, a few surviving pedio-cocci, lactobacilli, or wild yeasts may grow and produce off-flavors in the beer. Though the juices are not fermentation products, they nevertheless provide the perfect media for bacteria growth. In all cases, it is important to produce a sealed sterile product. 

When a culture is examined microscopically for its morphological characteristics a number of points need to be noted. The initial one is the appearance of the cells, whether they are cocci or rods, and whether the cells are arranged singly, in filaments, in groups, or in chains. In a few groups of bacteria, it may be difficult to decide whether the cells are cocci or rods. This problem may be related to the stage of the growth cycle from which the cells were taken. 

Many names have been assigned to the lactic acid bacteria associated with brewing. It is probable however that most rod-shaped isolates may be classified as the heterofermentative species Lactobacillus brevis, the homo-fermentative species . casei and L, plantarum, and the homofermentative thermophilic species L. delbrueckii [14]. Cocci are also encountered, notably the homofermentative Pediococcus damnosus. (Less common because they are more sensitive to hop resins are P. pentosaceuslacidilactici. Streptococcus saprophyticus, S. epidermis and Micrococcus varians.) Micrococcus kristinae is however resistant to hop resins and low pH, but requires oxygen for growth [15]. An American report states that many breweries encounter L. brevis, L. plantarum and P. damnosus. When the primary fermentation is complete, Pediococcus continues to grow at the bottom of the fermenter in the deposited yeast [16]. 

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