This book makes the vast and complex field of medical microbiology more accessible by the use of four-color graphics and numerous illustrations with detailed. Color Atlas of Diagnostic Microbiology - Free ebook download as PDF File .pdf) or read book online for free. Title: When the Moon Split: A biography of Prophet Muhammad (Peace be upon him) Author: Safiur-Rahman al-Mubarkpuri Subj.
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Request PDF on ResearchGate | On Jan 1, , W.C. Winn and others published Color Atlas an Textbook of Diagnostic Microbiology. editions of Microbiology Laboratory Theory and Application, one edition of Microbiology When we did the first edition, the Atlas broke the mold at Morton Publishing by including with the brown color (due to bismuth sulfite reduction) . Some Drugs and Herbal Products. RCS66 World Health. Organization,. International. Agency for. Research on. Cancer. USMLE® step 1.
Similar problems related to the number of microorganisms present affect the sensitivity of immunoassays and genetic probes for bacteria, chlamydiae, fungi and viruses. In some instances, the sensitivity of direct examination tests can be improved by collecting a better specimen. For example, the sensitivity of fluorescent antibody stain for Chlamydia trachomatis is higher when endocervical cells are obtained with a cytobrush than with a swab.
The sensitivity may also be affected by the stage of the disease at which the specimen is collected. For example, the detection of herpes simplex virus by immunofluorescence, immunoassay, or culture is highest when specimens from lesions in the vesicular stage of infection are examined. Finally, sensitivity may be improved through the use of an enrichment or enhancement step in which microbial or genetic replication occurs to the point at which a detection method can be applied.
Techniques For microscopic examination it is sufficient to have a compound binocular microscope equipped with low-power 1OX , high-power 40X , and oil immersion 1OOX achromatic objectives, 10X wide-field oculars, a mechanical stage, a substage condenser, and a good light source.
For examination of wet-mount preparations, a darkfield condenser or condenser and objectives for phase contrast increases image contrast. An exciter barrier filter, darkfield condenser, and ultraviolet light source are required for fluorescence microscopy.
For immunologic detection of microbial antigens, latex particle agglutination, coagglutination, and enzyme-linked immunosorbent assay ELISA are the most frequently used techniques in the clinical laboratory. Antibody to a specific antigen is bound to latex particles or to a heat-killed and treated protein A-rich strain of Staphylococcus aureus to produce agglutination Fig. There are several approaches to ELISA; the one most frequently used for the detection of microbial antigens uses an antigen-specific antibody that is fixed to a solid phase, which may be a latex or metal bead or the inside surface of a well in a plastic tray.
Antigen present in the specimen binds to the antibody as in Fig. The test is then completed by adding a second antigen-specific antibody bound to an enzyme that can react with a substrate to produce a colored product. The initial antigen antibody complex forms in a manner similar to that shown in Figure When the enzyme-conjugated antibody is added, it binds to previously unbound antigenic sites, and the antigen is, in effect, sandwiched between the solid phase and the enzyme-conjugated antibody.
The reaction is completed by adding the enzyme substrate. Figure Agglutination test in which inert particles latex beads or heat-killed S aureus Cowan 1 strain with protein A are coated with antibody to any of a variety of antigens and then used to detect the antigen in specimens or in isolated bacteria.
Once such a unique nucleotide sequence, which may represent a portion of a virulence gene or of chromosomal DNA, is found, it is isolated and inserted into a cloning vector plasmid , which is then transformed into Escherichia coli to produce multiple copies of the probe.
The sequence is then reisolated from plasmids and labeled with an isotope or substrate for diagnostic use.
The use of molecular technology in the diagnoses of infectious diseases has been further enhanced by the introduction of gene amplication techniques, such as the polymerase chain reaction PCR in which DNA polymerase is able to copy a strand of DNA by elongating complementary strands of DNA that have been initiated from a pair of closely spaced oligonucleotide primers.
This approach has had major applications in the detection of infections due to microorganisms that are difficult to culture e.
Culture In many instances, the cause of an infection is confirmed by isolating and culturing microorganism either in artificial media or in a living host. Bacteria including mycobacteria and mycoplasmas and fungi are cultured in either liquid broth or on solid agar artificial media.
Liquid media provide greater sensitivity for the isolation of small numbers of microorganisms; however, identification of mixed cultures growing in liquid media requires subculture onto solid media so that isolated colonies can be processed separately for identification. Growth in liquid media also cannot ordinarily be quantitated. Solid media, although somewhat less sensitive than liquid media, provide isolated colonies that can be quantified if necessary and identified.
Some genera and species can be recognized on the basis of their colony morphologies. In some instances one can take advantage of differential carbohydrate fermentation capabilities of microorganisms by incorporating one or more carbohydrates in the medium along with a suitable pH indicator.
Such media are called differential media e. Different genera of the Enterobacteriaceae can then be presumptively identified by the color as well as the morphology of colonies. Culture media can also be made selective by incorporating compounds such as antimicrobial agents that inhibit the indigenous flora while permitting growth of specific microorganisms resistant to these inhibitors.
One such example is Thayer-Martin medium, which is used to isolate Neisseria gonorrhoeae. This medium contains vancomycin to inhibit Gram-positive bacteria, colistin to inhibit most Gram-negative bacilli, trimethoprim-sulfamethoxazole to inhibit Proteus species and other species that are not inhibited by colistin and anisomycin to inhibit fungi.
The pathogenic Neisseria species, N gonorrhoeae and N meningitidis, are ordinarily resistant to the concentrations of these antimicrobial agents in the medium.
The number of bacteria in specimens may be used to define the presence of infection.
For this reason, quantitative cultures Fig. For most other specimens a semiquantitative streak method Fig. For quantitative cultures, a specific volume of specimen is spread over the agar surface and the number of colonies per milliliter is estimated.
For semiquantitative cultures, an unquantitated amount of specimen is applied to the agar and diluted by being streaked out from the inoculation site with a sterile bacteriologic loop Fig. Figure Quantitative versus semiquantitative culture, revealing the number of bacteria in specimens. Chlamydiae and viruses are cultured in cell culture systems, but virus isolation occasionally requires inoculation into animals, such as suckling mice, rabbits, guinea pigs, hamsters, or primates.
Rickettsiae may be isolated with some difficulty and at some hazard to laboratory workers in animals or embryonated eggs. For this reason, rickettsial infection is usually diagnosed serologically. Some viruses, such as the hepatitis viruses, cannot be isolated in cell culture systems, so that diagnosis of hepatitis virus infection is based on the detection of hepatitis virus antigens or antibodies. Since clinical specimens from bacterial infections often contain aerobic, facultative anaerobic, and anaerobic bacteria, such specimens are usually inoculated into a variety of general purpose, differential, and selective media, which are then incubated under aerobic and anaerobic conditions Fig.
The duration of incubation of cultures also varies with the growth characteristics of the microorganism. Most aerobic and anaerobic bacteria will grow overnight, whereas some mycobacteria require as many as 6 to 8 weeks. Microbial Identification Microbial growth in cultures is demonstrated by the appearance of turbidity, gas formation, or discrete colonies in broth; colonies on agar; cytopathic effects or inclusions in cell cultures; or detection of genus- or species-specific antigens or nucleotide sequences in the specimen, culture medium, or cell culture system.
Identification of bacteria including mycobacteria is based on growth characteristics such as the time required for growth to appear or the atmosphere in which growth occurs , colony and microscopic morphology, and biochemical, physiologic, and, in some instances, antigenic or nucleotide sequence characteristics.
The selection and number of tests for bacterial identification depend upon the category of bacteria present aerobic versus anaerobic, Gram-positive versus Gram-negative, cocci versus bacilli and the expertise of the microbiologist examining the culture.
Gram-positive cocci that grow in air with or without added CO2 may be identified by a relatively small number of tests see Ch. The identification of most Gram-negative bacilli is far more complex and often requires panels of 20 tests for determining biochemical and physiologic characteristics. The identification of filamentous fungi is based almost entirely on growth characteristics and colony and microscopic morphology.
VetBooks January 11, Like 7. Description to come Features: A new-full color design clarifies important concepts and engages students. Updated and expanded coverage of the mycology and molecular chapters reflect the latest advances in the field. New clinical scenarios demonstrate key applications of microbiology in the real world. Additional high quality images enhance visual understanding. Clinical correlations link microorganisms to specific disease states using references to the most current medical literature available.
Practical guidelines for cost-effective, clinically relevant evaluation of clinical specimens include extent of workup and abbreviated identification schemes.
This knowledge is a necessary prerequisite for the diagnosis, therapy, and prevention of infectious diseases. This book addresses primarily students of medicine, dentistry, and pharmacy. Beyond this academic purpose, its usefulness extends to all medical professions and most particularly to physicians working in both clinical and private practice settings.
This book makes the vast and complex field of medical microbiology more accessible by the use of four-color graphics and numerous illustrations with detailed explanatory legends.
The many tables present knowledge in a cogent and useful form. Most chapters begin with a concise summary, and in-depth and supplementary knowledge are provided in boxes separating them from the main body of text.
This textbook has doubtless benefited from the extensive academic teaching and the profound research experience of its authors, all of whom are recognized authorities in their fields.