Ebook Microbiological applications: Laboratory manual in general microbiology: Part 2
➤ Gửi thông báo lỗi ⚠️ Báo cáo tài liệu vi phạmNội dung chi tiết: Ebook Microbiological applications: Laboratory manual in general microbiology: Part 2
Ebook Microbiological applications: Laboratory manual in general microbiology: Part 2
Benton: Microbiological XL Mkrobiologi oi Water Introduction Application: lab Manual.Eighth EditionI iDTbeMcGaw-HilCrrnwiK. iOjlPari11Microbiology of Ebook Microbiological applications: Laboratory manual in general microbiology: Part 2 WaterThe microorganisms of natural waters are extremely diverse. The numbers and types of bacteria present will depend on the amounts of organic matter present, the presence of toxic substances, the water’s saline content, and environmental factors such as pH, temperature. and aeration. The largest Ebook Microbiological applications: Laboratory manual in general microbiology: Part 2 numbers of heterotrophic forms will exist on the bottoms and banks of rivers and lakes where organic matter predominates. Open water in the center ofEbook Microbiological applications: Laboratory manual in general microbiology: Part 2
large bodies of water. free of floating debris, will have small numbers of bacteria. Many species of autotrophic types are present, however, that reqBenton: Microbiological XL Mkrobiologi oi Water Introduction Application: lab Manual.Eighth EditionI iDTbeMcGaw-HilCrrnwiK. iOjlPari11Microbiology of Ebook Microbiological applications: Laboratory manual in general microbiology: Part 2prime concern of everyone. The enteric diseases such as cholera, typhoid fever, and bacillary dysentery Otten result in epidemics when water supplies are not properly protected or treated. Thus, our prime concern in this unit is the sanitary phase of water microbiology. The American Public Health As Ebook Microbiological applications: Laboratory manual in general microbiology: Part 2sociation In its Standard Methods for the Examination ot Water and Wastewater has outlined acceptable procedures for testing water for sewage contaminEbook Microbiological applications: Laboratory manual in general microbiology: Part 2
ation. The exercises of this unit are based on the procedures in that book.221Benign: Microbiological XL Mkrobiologr of Water I 43. BacteriologicalAppBenton: Microbiological XL Mkrobiologi oi Water Introduction Application: lab Manual.Eighth EditionI iDTbeMcGaw-HilCrrnwiK. iOjlPari11Microbiology of Ebook Microbiological applications: Laboratory manual in general microbiology: Part 2e TestsWater that contains large numbers of bacteria may be perfectly safe to drink. The important consideration, from a microbiological standpoint, is the kinds of microorganisms that are present. Water from streams and lakes that contain multitudes of autotrophs and saprophytic heterotrophs is pot Ebook Microbiological applications: Laboratory manual in general microbiology: Part 2able as long as pathogens for humans are lacking. The intestinal pathogens such as those that cause typhoid fever, cholera, and bacillary dysentery arEbook Microbiological applications: Laboratory manual in general microbiology: Part 2
c of prime concern. The fact that human fecal material is carried away by water in sewage systems that often empty into rivers and lakes presents a coBenton: Microbiological XL Mkrobiologi oi Water Introduction Application: lab Manual.Eighth EditionI iDTbeMcGaw-HilCrrnwiK. iOjlPari11Microbiology of Ebook Microbiological applications: Laboratory manual in general microbiology: Part 2of water purity.Routine examination of water for the presence of intestinal pathogens would be a tedious and difficult, if not impossible, task. It is much easier to demonstrate the presence of some nonpathogenic intestinal types such as Escherichia coli or Streptococcus fae-calls. Since these organ Ebook Microbiological applications: Laboratory manual in general microbiology: Part 2isms are always found in the intestines, and normally are not present in soil or water. it can be assumed that their presence in water indicates thatEbook Microbiological applications: Laboratory manual in general microbiology: Part 2
fecal material has contaminated the water supply.E. call and s. faecalis are classified as good sewage indicators. The characteristics that make them Benton: Microbiological XL Mkrobiologi oi Water Introduction Application: lab Manual.Eighth EditionI iDTbeMcGaw-HilCrrnwiK. iOjlPari11Microbiology of Ebook Microbiological applications: Laboratory manual in general microbiology: Part 2survive a little longer in water than enteric pathogens. If they were hardy organisms, surviving a long time in water, they would make any water purity test too sensitive. Since both organisms arc non-sporc-fonners. their survival in water is not extensive.E. coll and s. faecalis arc completely diff Ebook Microbiological applications: Laboratory manual in general microbiology: Part 2erent organisms. E. call is a gram-negative non-spore-forming rod; 5. faecalis is a gram-positive coccus. The former is classified as a coliform; theEbook Microbiological applications: Laboratory manual in general microbiology: Part 2
latter is an enterococcus. Physiologically, they are also completely different.The series of tests depicted in figure 63.1 is based on tests that willBenton: Microbiological XL Mkrobiologi oi Water Introduction Application: lab Manual.Eighth EditionI iDTbeMcGaw-HilCrrnwiK. iOjlPari11Microbiology of Ebook Microbiological applications: Laboratory manual in general microbiology: Part 2am-negative, non-spore-forming rod. Escherichia call and Enlembacter aemgenes lit this description.Since S.Jaecalis is not a coliform, a completely different set of tests must be used for it.Note that three different tests are shown in figure 63.1: presumptive, confirmed, and completed. Each test ex Ebook Microbiological applications: Laboratory manual in general microbiology: Part 2ploits one or more of the characteristics of a coliform. A description of each test follows.Presumptive Test In the presumptive test a series of 9 orEbook Microbiological applications: Laboratory manual in general microbiology: Part 2
12 tubes of lactose broth are inoculated with measured amounts of water to see if the water contains any lactosc-fcrmenting bacteria that produce gas.Benton: Microbiological XL Mkrobiologi oi Water Introduction Application: lab Manual.Eighth EditionI iDTbeMcGaw-HilCrrnwiK. iOjlPari11Microbiology of Ebook Microbiological applications: Laboratory manual in general microbiology: Part 2 to determine the most probable number (MPN) of conforms present per It to ml of water.Confirmed Test In this test, plates of Levine EMB agar or Endo agar arc inoculated from positive (gasproducing) tubes to see if the organisms that are producing the gas are gram-negative (another coliform characte Ebook Microbiological applications: Laboratory manual in general microbiology: Part 2ristic). Both of these media inhibit the growth of gram-positive bacteria and cause colonies of conforms to be distinguishable from noncoliforms. On EEbook Microbiological applications: Laboratory manual in general microbiology: Part 2
MB agar conforms produce small colonies with dark centers (nucleated colonies). On Endo agar conforms produce reddish colonies. The presence of colifoBenton: Microbiological XL Mkrobiologi oi Water Introduction Application: lab Manual.Eighth EditionI iDTbeMcGaw-HilCrrnwiK. iOjlPari11Microbiology of Ebook Microbiological applications: Laboratory manual in general microbiology: Part 2e if the isolate from the agar plates truly matches our definition of a coliform. Our media for this lest include a nutrient agar slant and a Durham tube of lactose broth. If gas is produced in the lactose tube and a slide from the agar slant reveals that we have a gram-negative non-sporc-forming ro Ebook Microbiological applications: Laboratory manual in general microbiology: Part 2d. we can be certain that we have a coliform.The completion of these three tests with positive results establishes that conforms are present; however,Ebook Microbiological applications: Laboratory manual in general microbiology: Part 2
there is no certainty that E. coll is the coliform present. The organism might be E. aerogenes. Of the two. E. coli is the better sewage indicator siBenton: Microbiological XL Mkrobiologi oi Water Introduction Application: lab Manual.Eighth EditionI iDTbeMcGaw-HilCrrnwiK. iOjlPari11Microbiology of Ebook Microbiological applications: Laboratory manual in general microbiology: Part 2cteriologicalApplications lab Manual.Examination of Water:Eighth EditionQualitative TestsI ID The ttCnw-HilCrTOfsriK. .'iljtBacleriulogk-ul Examination of Water; Qualitative Tests • Exorcise 63 Ebook Microbiological applications: Laboratory manual in general microbiology: Part 2Benton: Microbiological XL Mkrobiologi oi Water Introduction Application: lab Manual.Eighth EditionI iDTbeMcGaw-HilCrrnwiK. iOjlPari11Microbiology ofGọi ngay
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