Culture

The communication with the laboratory is very important. The laboratory should be informed if any of these pathogens is suspected or if the patient has taken antibiotics. While most samples are spread on Universalnährmedien (. Eg blood or cook blood agar), some pathogen-specific nutrients and inhibitors or other special conditions require (see table: Selective media for the isolation of the common bacteria). The origin of the material must be specified so that the laboratory can differentiate pathogens from site Flora.

A culture is microbial growth on or in a solid or liquid nutrient medium; cultivating microorganisms facilitates the identification. A culture also facilitates the antibiotic susceptibility testing. The communication with the laboratory is very important. The laboratory should be informed if any of these pathogens is suspected or if the patient has taken antibiotics. While most samples are spread on Universalnährmedien (. Eg blood or cook blood agar), some pathogen-specific nutrients and inhibitors or other special conditions require (see table: Selective media for the isolation of the common bacteria). The origin of the material must be specified so that the laboratory can differentiate pathogens from site Flora. Selective media for the isolation of the common bacteria organism Preferred medium Bacteroides sp. Kanamycin-Vancomycin laked blood agar Bacteroides fragilis Bacteroides Bile Esculin (with gentamicin and bile) Bordetella pertussis Bordet-Gengou agar plus. Methicillin or cephalexin Regan agar Lowe cephalexin horse blood charcoal agar Burkholderia cepacia Pseudomonas cepacia agar Campylobacter jejuni or C. coli Campylobacter -selective nutrient media (eg. as vancomycin cefoperazone agar) Corynebacterium diphtheria Tinsdale agar cystine-tellurite blood agar Löffler coagulated serum medium Escherichia coli or enterohemorrhagic pathogens (Shiga toxin-producers, including O157-H7) MacConkey sorbitol agar Francisella tularensis blood or chocolate-cystine agar Legionella sp Buffered charcoal yeast extract agar Leptospira sp Fletcher- or Stuart medium with rabbit serum or Leptospira medium with Rin serum albumin-Tween gonorrhoeae 80 Neisseria or N. meningitidis Modified Thayer-Martin Agar New York City agar Salmonella and Shigella sp Can on standard MacConkey or eosin methylene blue grow alternative: Hektoen or xylose lysine deoxycholate, Salmonella Shigella agar, gram-negative or selenite enrichment broth Vibrio sp thiosulfate-citrate-bile acids sucrose agar Yersinia sp cefsulodin Irgasan novobiocin-agar Specimen collection The sampling is crucial. For the diagnosis of infectious diseases is the rule of thumb is to take the sample where the infection is. For injuries, the leading edge should not the center, are scanned. The use of cotton buds is not recommended. However, if a swab is used, a flocked swab is preferred because it can take more samples. Swabs that are used for molecular tests (nucleic acid-based identification method for infectious diseases) must be compatible for these specific tests. An incorrect swab may cause false negative results. Wooden shafted swabs are toxic for some viruses. Swabs with cotton are toxic to some bacteria including chlamydia. Blood cultures require decontamination and disinfection of the skin (z. B. be dried povidone iodine swab with 70% alcohol removed). Usually several samples are used by each different points; If possible, they should be taken concurrently with the bouts of fever. Germs of the resident flora of the skin and mucous membranes are usually interpreted as contamination when they are cultured in a single blood culture bottle. If a blood sample from a central venous catheter (CVC) is removed, and a peripheral blood sample should be removed in order to be able to distinguish a systemic bacteremia from a catheter infection. Cultures of infected catheters faster generally positive and contain more pathogens than simultaneously detached peripheral blood cultures. Some types of fungi, in particular molds (eg., Aspergillus spp.), Usually can not be cultured in blood cultures. Samples must be transported quickly and in the correct medium and under conditions that limit the growth of any contaminating resident flora. For a correct determination of the number of germs pathogens, an additional multiplication of pathogens must be prevented; Therefore samples should be transported immediately to the laboratory or cooled when the transport delay. Special considerations for Culture Certain crops require special conditions: Anaerobic bacteria should not be grown from locations where they are physiologically present, since they can not be distinguished from the physiological flora if necessary. Samples must be protected from exposure to air, which can be difficult. For swabs anaerobic transport media are available. However, samples are fluid (eg. B. Abszessinhalte) superior smears for the recovery of anaerobic bacteria. Fluid samples should be collected with a syringe, the entire air was expressed (in order to minimize the contact of the sample with oxygen) and are sent in the syringe (without needle capped) to a laboratory or placed in an anaerobic transport vial. Mycobacteria are difficult to breed. Samples which contain normal flora (z. B. ejection) must be decontaminated and enriched only. Mycobacterium tuberculosis and some other mycobacteria grow slowly. The growth of M. tuberculosis is faster in liquid and in solid media in general; routine use of automated systems with liquid media can be on solid media such as Lowenstein-Jensen agar in growth within 2 wk. vs ? 4 wk. to lead. Furthermore, only a few pathogens in a sample may be present. Several samples from the same location can increase the yield. The samples should be incubated for 8 weeks before they are discarded. In V. a. atypical mycobacteria, the laboratory should be informed. Viruses are usually grown from smears and tissue samples are transported in media with antibacterial and antifungal substances. The samples are applied to cell cultures that favor the growth of the suspected viruses and inhibit any other pathogen. Very sensitive viruses (eg. As varicella-zoster virus) should be applied to cell cultures within 1 hour. Standard cell cultures are most sensitive on. Short-term cell cultures (Shell vials) can lead to faster results. Some common viruses can not be detected using routine culture methods and require alternative methods for diagnosis (see table: Diagnostic tests for common viruses that do not grow in normal viral cultures), such as the following: Enzyme Immunoassay for Epstein-Barr virus, hepatitis B and e viruses, HIV and human T lymphotropic virus Serological tests for hepatitis A and D virus nucleic acid-based methods for HIV diagnostic tests for common viruses that do not grow in normal viral cultures Terms and conditions virus Special Diagnostic tests Acute febrile illness, meningoencephalitis alphavirus, flavivirus, Bunya (eg. As St. Louis encephalitis virus, La Crosse encephalitis virus) EIA, nucleic acid-based methods diarrhea rotavirus, Callciviren (norovirus), Astro viruses EM or IEM, nucleic acid-based methods Infectious mononucleosis Epstein-Barr virus EIA, nucleic acid-based methods Hemorrhagic fever, lymphocytic choriomeningitis filoviruses, arena viruses (eg. as Lassa fever, Ebola virus) EM, nucleic acid-based methods Hepatitis Hepatitis A, Hepatitis D Serological tests, nucleic acid-based methods Hepatitis B, Hepatitis E EIA, nucleic acid-based methods Hepatitis C, Hepatitis G nucleic acid-based methods, EIA roseola, Kaposi’s sarcoma, disseminated infections herpes viruses 6, 7, 8, nucleic acid-based methods, EIA AIDS HIV nucleic acid-based methods, EIA, Western blot genital warts, genital skin cancer human papillomavirus nucleic acid-based methods, EIA fifth disease Human parvovirus B19 nucleic acid-based methods, EIA adult T-cell leukemia Human T-cell lymphotropic virus EIA, nucleic acid-based methods Pro sive multifocal leukoencephalopathy, kidney infection polyoma virus (JC and BK) nucleic acid-based methods smallpox, monkeypox, vaccinia, molluscum pox virus nucleic acid-based methods, EM, culture depending on the virus rabies (rabies) rabies virus EM, IFA, nucleic acid-based methods rubella rubella virus EIA, IFA, nucleic acid-based methods EIA = enzyme immunoassay, EM = electron microscopy; IEM = immunoelectron microscopy; IFA = immunofluorescence assay. Mushroom samples from non-sterile sites must be applied to media containing antibacterial substances. The samples should be incubated for 3 to 4 weeks before they are discarded.

Health Life Media Team

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