Blood culturing
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Blood culturing in Infections

Blood culturing in Infections

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    Dr.T.V.Rao MD
    Dr.T.V.Rao MD
  • 2. What is a Blood Culture?
    A blood culture is a laboratory test in which blood is injected into bottles with culture media to determine whether microorganisms have invaded the patient’s bloodstream.
    Dr.T.V.Rao MD
  • 3. Need for Blood Culture?
    No microbiological test is more essential to the clinician than the blood culture. The finding of pathogenic microorganisms in a patient’s bloodstream is of great importance in terms of diagnosis, prognosis, and therapy.”
    - L. Barth Reller, Clin. Infect. Diseases, 1996
    Dr.T.V.Rao MD
  • 4. Blood Culture is done to Detect Infectious Diseases
    Blood culture is a microbiological culture of blood. It is employed to detect infections that are spreading through the bloodstream (such as bacteremia, septicemia amongst others). This is possible because the bloodstream is usually a sterile environment
    Dr.T.V.Rao MD
  • 5. Proof in Blood borne Infection
    • A clinically suspected infection is ultimately confirmed by isolation or detection of the infectious agent. Subsequent identification of the microorganism and antibiotic susceptibility tests further guide effective antimicrobial therapy. Bloodstream infection is the most severe form of infection and is frequently life-threatening, and blood culture to detect circulating microorganisms has been the diagnostic standard.
    Dr.T.V.Rao MD
  • 6. Bacteremia – presence of bacteria in blood stream
    Some conditions have a period of bacteremia as part of the disease process (ex. Meningitis, endocarditis)
    Septicemia – bacteremia plus clinical signs and symptoms of bacterial invasion and toxin production
    Dr.T.V.Rao MD
  • 7. Dr.T.V.Rao MD
  • 8. Definitions (cont’d)
    Primary Bacteremia – blood stream bacterial invasion with no preceding or simultaneous site of infection with the same microorganism
    Secondary Bacteremia – isolation of a microorganism from blood as well as other site(s)
    Dr.T.V.Rao MD
  • 9. Bacteremia and Fungemia Episodes
    Comes and goes
    Usually occurs after a procedural manipulation (ex. Dental procedures)
    Can occur from abscesses at some body site that is “seeding” the blood
    Continuous Bacteremia
    Dr.T.V.Rao MD
  • 10. Warm shock – fever, increased pulse, hyperventilation, and warm, dry flushed skin
    Cold shock – decreased blood pressure, increased pulse, and rapid, shallow respirations
    Septic chock
    Hemodynamic changes, decreased tissue perfusion and compromised organ & tissue function
    Mortality 40% to 50%
    Bacteremia Complications
    Dr.T.V.Rao MD
  • 11. Bacteremia/Septicemia Risk Factors
    Immunocompromised patients
    Increased use of invasive procedures
    Age of patient
    Administration of drug therapy
    Dr.T.V.Rao MD
  • 12. Sources of Bacteremia Spread
    Pericarditis and Peritonitis
    Pressure sores
    Prosthetic medical devices
    Total hip replacement
    Skeletal system
    Skin and soft tissue
    Dr.T.V.Rao MD
  • 13. Blood culturing most important and life saving Investigation
    Needs optimal Methods for Diagnosis of Blood Borne Pathogens
    Dr.T.V.Rao MD
  • 14. BloodCollection
    Aseptic collection procedure is critical Amount of blood
    1:10 ratio of blood to broth
    Younger than 10 years – 1 ml of blood for every year of life
    Over 10 years – 20 ml
    Dr.T.V.Rao MD
  • 15. Blood Collection
    Frequency of Collection
    Depends if bacteremia is transient, intermediate or continuous
    Number of cultures collected are usually inversely related to the type of bacteremia
    Usually x3 from different body sites
    Dr.T.V.Rao MD
  • 16. Conventional Broth Systems
    One aerobic bottle and one anaerobic bottle per blood collection
    Aerobic broth contains soybean casein digest broth, Tryptic or trypticase soy broth, Brucella agar or Columbia broth base
    Anaerobic broth is usually the same as aerobic with addition of 0.5% cysteine in an aerobic environment
    Must be subcultured and gram stained manually
    Blood Culture Methods
    Dr.T.V.Rao MD
  • 17. Venipuncture
    Venipunctureis the process of obtaining intravenous access for the purpose of intravenous therapy or obtaining a sample of venous blood. This procedure is performed by medical laboratory scientists, medical practitioners, some EMTs, paramedics phlebotomists and other nursing staff. Venipuncture is one of the most routinely performed invasive procedures and is carried out for two reasons, to obtain blood for diagnostic purposes or to monitor levels of blood components (Lavery & Ingram 2005).
    Dr.T.V.Rao MD
  • 18. Phlebotomy Definition
    phle·boto·my (fli) nounthe act or practice of bloodletting as a therapeutic measure
    Phlebotomy from Greek words, phlebo, relates to veins, tomy, relates to cutting.
    Opening a vein to collect blood
    Dr.T.V.Rao MD
  • 19. Properly labelled sample is essential so that the results of the test match the patient. The key elements in labelling are:
    Patient's surname, first and middle.
    Patient's ID number.
    NOTE: Both of the above MUST match the same on the requisition form.
    Date, time and initials of the phlebotomist must be on the label of EACH tube.
    Dr.T.V.Rao MD
  • 20. Principles for Collection
    Gloves will be worn in accordance with standard precautions.
    •Appropriate verification of the patient's identity, by means of an armband or area specific procedure, will occur before the specimen collection.
    •Cultures should be drawn before administration of antibiotics, if possible. ???
    • blood cultures should be drawn from lines, but should be drawn viavenipuncture.
    Dr.T.V.Rao MD
  • 21.
    • Chlorhexidine swabs (1-2 packages)
    • 22. Alcohol swabs
    • 23. Blood culture bottles (2 bottles per set)
    • 24. 2 syringes (adult: 20 cc, paediatric: 5 cc)
    • 25. 2 needles (adult: 22 gauge or preferably larger butterfly or standard needle; pediatric: 25 or 23 gauge butterfly or standard needle)
    • 26. Gloves (sterile &nonsterile)
    • 27. Tourniquet
    • 28. Sterile gauze pad
    • 29. Adhesive strip or tape
    • 30. Self-sticking patient labels
    • 31. Plastic zip lock specimen bags
    What Materials We need
    Dr.T.V.Rao MD
  • 32. The requisitions form should be completely filled out, and the requisition must indicate the tests ordered.
    Dr.T.V.Rao MD
  • 33. Self Protection
    A few ways to make sure your role in the collection process is carried out with efficiency, orderliness and safety
    Dr.T.V.Rao MD
  • 34. Steps 1 – 3, Check, Explain, Wash
    1.Identify the patient
    2.Explain the procedure to the patient.
    3.Wash hands with soap and water withfriction for 15 seconds or use alcohol based hand rub
    Dr.T.V.Rao MD
  • 35. Materials
    • Chlorhexidine swabs (1-2 packages)
    • 36. Alcohol swabs
    • 37. Blood culture bottles (2 bottles per set)
    • 38. 2 syringes (adult: 20 cc, paediatric: 5 cc)
    • 39. 2 needles (adult: 22 gauge or preferably larger butterfly or standard needle; pediatric: 25 or 23 gauge butterfly or standard needle)
    • 40. Gloves (sterile &nonsterile)
    • 41. Tourniquet
    • 42. Sterile gauze pad
    • 43. Adhesive strip or tape
    • 44. Self-sticking patient labels
    • 45. Plastic zip lock specimen bags
    Dr.T.V.Rao MD
  • 46. . Barrier protection for the phlebotomist consists of the latex gloves.
    Dr.T.V.Rao MD
  • 47. Locate the vein
    Prep kit
    Alcohol 5 sec. Dry 30-60 sec ( resource poor conditions )
    Ideal to collect with alcohol swabs containing 2% Chlorhexidine and 70% isopropyl alcohol
    Remove caps, clean with alcohol
    Put on gloves
    Without palpating, draw 20 ml and put 10 in anaerobic and 10 in aerobic bottle
    Dispose of syringe in sharps container
    Label bottles and send to lab
    Obtaining Blood
    Dr.T.V.Rao MD
  • 48. Method of Blood Collection
    A minimum of 10 ml of blood is taken through venipuncture and injected into two or more "blood bottles" with specific media for aerobic and anaerobic organisms.
    The blood is collected using clean technique. This requires that both the tops of the culture bottles and the venipuncture site of the patient are cleaned prior to collection with alcohol swabs containing 2% Chlorhexidine and 70% isopropyl alcohol.
    Dr.T.V.Rao MD
  • 49. The area of skin is cleaned with a disinfectant, or an alcohol swab.
    Using sterile gloves, do not wipe away the surgical solution, touch the puncture site, or in any way compromise the sterile process. It is vital that the procedure is performed in as sterile a manner as possible as the persistent presence of skin commensals in blood cultures could indicate endocarditis but they are most often found as contaminants
    Dr.T.V.Rao MD
  • 50. The vein is anchored and the needle is inserted.
    Dr.T.V.Rao MD
  • 51. The vacutainer tube is depressed into the needle to begin drawing blood
    Dr.T.V.Rao MD
  • 52. Additional vacutainer tubes can be utilized. Determine what tests are ordered and what tubes will be necessary BEFORE you begin to draw blood, and determine the order of draw for the tubes..
    Dr.T.V.Rao MD
  • 53. When the final tube is being drawn, release the tourniquet. Then remove the tube, and remove the needle.
    Dr.T.V.Rao MD
  • 54. After the needle is removed from the vein, apply firm pressure over the site to achieve haemostasis.
    Dr.T.V.Rao MD
  • 55. Apply a bandage to the area.
    Dr.T.V.Rao MD
  • 56. Preparation of Cap before Injecting Blood
    Prep the rubber cap of the blood culture bottles with an alcohol pad in a circular motion. Allow the alcohol to dry.
    Dr.T.V.Rao MD
  • 57. Inject the Blood …..
    Inject the blood into the Selected Media
    Gently rotate the bottles to mix the blood & the broth (do not shake vigorously).
    Dr.T.V.Rao MD
  • 58. Follow the universal precautions when disposing Needle
    Dispose of needle in sharps container and dispose of other waste in proper container
    Dr.T.V.Rao MD
  • 59. Label the tubes, checking the requisition for the proper identification.
    Dr.T.V.Rao MD
  • 60. Patient’s name
    • Hospital number (Patient ID)
    • Patient’s location (room and bed #)
    • Date and time of collection
    • Collector’s initials
    • Site of venipuncture
    • Or other information as per facility
    Include you Mobile Contact No – A vital information can be delivered any time
    Give the all possible Medical Information
    Dr.T.V.Rao MD
  • 61. Document the Medical Records
    Document the following in the medical record:
    –Date & time specimen obtained
    –Site of specimen collection
    Dr.T.V.Rao MD
  • 62. Frequency of Collection
    Frequency of Collection
    Depends if bacteremia is transient, intermediate or continuous
    Number of cultures collected are usually inversely related to the type of bacteremia
    Usually x3 from different body sites
    Dr.T.V.Rao MD
  • 63. Second Set
    If 2 or more sets of blood cultures have been ordered, obtain the second set in the same manner as the first, making a new venipuncture at a different site.
    Dr.T.V.Rao MD
  • 64.
    • Most microbiological culture procedures require the use of solid media, like blood agar and Mac Conkeys agar plates that need to be visually monitored by trained personnel at intervals of 24 hours. These conventional cultures using normal media take at least a minimum of 72 hours to isolate the pathogen and carry out susceptibility test to know the efficacy of antibiotics on simple aerobic bacteria.
    Traditional Methods in Blood cultures
    Dr.T.V.Rao MD
  • 65. Bacteria and Fungi Are Identified by Phenotypic Characters
    Dr.T.V.Rao MD
  • 66. Biochemical Tests gives Better Clues in Identification
    Dr.T.V.Rao MD
  • 67. Newer Blood Culture Methods
    Newer Blood Culture Systems
    Biphasic Broth-Slide System
    Agar “paddles” attached to top of bottle
    Closed system
    Continuous Monitoring Blood Culture Systems
    BacTec – measures 14CO2
    BacTec 9000 Series – measures CO2
    ESP – measures consumption of gases
    BacT-Alert – measures change in pH
    Dr.T.V.Rao MD
  • 68. Automation reduces the time requirement
    But this can be completed within 30 hours by using automated techniques. This is especially useful when large number of specimens needs to be cultured, as the instrument, which has been programmed for the same, automatically screens these.
    Dr.T.V.Rao MD
  • 69. BacT/AlerT 3D culture system
    • BacT/AlerT 3D culture system. This is the first automated non-radiometric and non-invasive culture system that continuously monitors system for culture of bacteria (both aerobic and anaerobic), fungi and mycobacteria. All these bacteria can be cultured using different media as prescribed..
    Dr.T.V.Rao MD
  • 70. bioMérieux BacT/ALERT® 3D
    • The bioMérieux BacT/ALERT® 3D provides an optimal environment for the recovery of a wide range of pathological organisms, including bacteria, yeasts and mycobacteria; utilizing proprietary plastic culture bottles ensuring added safety to the user.
    Dr.T.V.Rao MD
  • 71. BacT/ALERT® 3D Microbial Detection System
    This newest generation of the time-tested BacT/ALERT system offers advantages in every dimension of testing. From its space-saving modular design to its easy touch-screen operation and flexible data management options, every laboratory will find something to love about the BacT/ALERT 3D!
    Dr.T.V.Rao MD
  • 72. Principles of functioning of BacT alert Monitors
    • Microorganisms multiply in the media, generating CO2. As CO2 increases, the sensor in the bottle turns a lighter colour.
    • 73. Measuring reflected light, the BacT/ALERT 3D monitors and detects color changes in the sensor.
    • 74. Algorithms analyze the data to determine positivity, and the laboratory is notified immediately with visual and audible alarms.
    Dr.T.V.Rao MD
  • 75. Principles in BacT/AlerT 3D culture system
    • This is a closed system and works on the colorimetric principle of detection of CO2 produced by the organisms. The CO2 causes a lowering of the pH of the medium, which in turn produces a colour change in a sensor attached to the CO2-sensitive base of each bottle.
    Dr.T.V.Rao MD
  • 76. Automation improves quality of services
    • Overall, laboratories transitioning from conventional to automated processes find that technologists and microbiologists are more open to innovation and improved quality.
    Dr.T.V.Rao MD
  • 77. After inoculating the culture vials, they are sent to the clinical pathology microbiology department. Here the bottles are entered into a blood culture machine, which incubate the specimens at body temperature. The blood culture instrument reports positive blood cultures (cultures with bacteria present, thus indicating the patient is "bacteremia"). Most cultures are monitored for 5 days after which negative vials are removed.
    Automation Signals Bacteremia cases
    Dr.T.V.Rao MD
  • 78. Avial is positive, a microbiologist will perform a Gram Stain on the blood for a rapid, general ID of the bacteria, which they will report to the attending physician of the bacteremic patient. The blood is also subcultured onto agar plates to isolate the pathogenic organism for culture and susceptibility testing, which takes up to 3 days. This culture & sensitivity (C&S) process identifies the species of bacteria. Antibiotic sensitivities are then assessed on the bacterial isolate to inform clinicians on appropriate antibiotics for treatment.
    The positives cases to be proceeded without delay
    Dr.T.V.Rao MD
  • 79. Culturing Mycobacterium from Blood
    Mycobacterial growth is generally observed within a week in case of smear (1+) positive.
    Speciation into mycobacterium tuberculosis complex and mycobacteria other than tuberculosis takes an additional three days.
    An important Investigation in AIDS and other Immunosuppressed patients
  • 80. Testing drug resistance in Tuberculosis a priority
    Susceptibility testing to primary line of anti-tuberculosis drugs viz streptomycin, isoniazid, rifampicin, ethambutol and pyrizinamide and secondary line of drugs viz kanamycin, para-amino salicylic acid, cycloserine, ethionamide, capreomycin etc requires 5-10 days.
  • 81. Rapid Susceptibility Testing
    Rapid susceptibility will be carried out for gram negative and staphylococcal isolates and other isolates on request. These will be reported within 12 hours using API systems. Automation has made it easier to arrive at a precise laboratory diagnosis of infection 
  • 82. If the skin is not adequately cleansed before drawing blood for culture, bacteria on the skin will be injected into the bottle, producing a false positive blood culture
    It is difficult for the physician to determine whether the bacteria growing in the blood culture is a real pathogen causing bloodstream infection or whether bacteria on the skin have contaminated the culture. This can lead to excess use of antibiotics and prolongation of hospital stay.
    The Contaminated Blood Culture
    Dr.T.V.Rao MD
  • 83. The programme created by Dr.T.V.Rao MD as Technical Series for Microbiologists in the Developing World
    Dr.T.V.Rao MD