Which type of meningitis is associated with negative bacterial culture of CSF?
Acute bacterial meningitis can be caused by different Gram-negative bacteria including meningococcal and H influenzae. This article covers Gram-negative meningitis caused by the following bacteria: Escherichia coli. Klebsiella pneumoniae.
What is culture negative meningitis?
Cases of partially treated bacterial meningitis may present as acute infection, usually with negative bacterial cultures. Re- sults with Gram’s stain may be positive or negative, depending on the organism and type of an- tibiotic therapy.
What is CSF negative?
A normal result means no bacteria, viruses, or fungi grew in the laboratory dish. This is called a negative result. However, a normal result doesn’t mean that an infection is present. The spinal tap and CSF smear may need to be done again.
What is the gold standard test for meningitis diagnosis?
The gold standard of diagnosis of meningitis is culture and PCR of cerebrospinal fluid (CSF) although in field settings, the positive rate from culture is relatively low due to suboptimal storage and transportation conditions, culture practice, and/or antibiotic treatment administered before the specimen is collected ( …
Why is CSF glucose low in bacterial meningitis?
The reason for the reduced glucose levels associated with bacterial meningitis was believed to be the need for glucose as fuel by infiltrating immune cells in response to infection. However, the possibility that the bacteria itself could manipulate glucose concentrations in the brain had not been explored before now.
How is meningitis diagnosed with CSF?
Spinal tap (lumbar puncture). For a definitive diagnosis of meningitis, you’ll need a spinal tap to collect cerebrospinal fluid (CSF). In people with meningitis, the CSF often shows a low sugar (glucose) level along with an increased white blood cell count and increased protein.
What does CSF look like in viral meningitis?
CSF: cerebrospinal fluid; WBC: white blood cell; RBC: red blood cell; ↑: elevated; ↓: decreased; NL: normal; SL: slightly. * In most cases of viral meningitis, the CSF WBC is within the range of 10 to 500 cells/microL, though higher values can be seen with some viruses.
Is meningitis Gram positive or negative?
Chapter 7: Identification and Characterization of Neisseria meningitidis. N. meningitidis are gram-negative, coffee-bean shaped diplococci that may occur intracellularly or extracellularly in PMN leukocytes. N.
Can blood culture detect meningitis?
To do a blood test for signs of meningitis, a technician inserts a needle into a vein in your arm and draws out a sample of your blood to send to a lab for testing. A complete blood count (CBC) or total protein count check for heightened levels of certain cells and proteins that can suggest a meningitis infection.
What labs are ordered for meningitis?
Which lab tests should be ordered in suspected meningitis?
- Blood, nasopharynx, respiratory secretion, urine or skin lesion cultures or antigen/polymerase chain reaction (PCR) detection assays.
- Syphilis testing.
- Serum procalcitonin testing.
- Lumbar puncture and CSF analysis.
- Neuroimaging (CT of the head or MRI of the brain)
What happens to CSF glucose in bacterial meningitis?
Low glucose in aseptic meningitis. Among aseptic meningitis cases (n = 115), only 11 cases (9.6%) had CSF glucose lower than 40 mg/dL (median 33, range 16–37 mg/dL).
What does CSF look like in bacterial meningitis?
Lumbar puncture (LP) cerebrospinal fluid (CSF) findings in bacterial meningitis include the following: Appearance: Clear, cloudy, or purulent. Opening pressure: Elevated (>25 cm H2 O) WBC count: >100 cells/µL (>90% PMN); partially treated cases may have as low as 1 WBC/µL.
How long do you centrifuge a meningitis culture?
In addition to known reference strains for N. meningitidis, S. pneumoniae, and H. influenzae, other reference strains that may be used include Staphylococcus aureus for gram-positive cocci and Escherichia coli for gram-negative rods. Centrifuge the CSF for 10-15 minutes at 1000 x g, if > 1 ml is available (see above).
How is CSF used in neurocritical care?
CSF analysis is particularly useful in various acute neurological conditions and helps in rapid diagnosis of the conditions and initiate therapeutic measures.
What kind of fluid is used to test for meningitis?
Microbiology laboratories commonly receive cerebrospinal fluid (CSF) or blood specimens from patients with meningitis, pneumonia, or unexplained febrile illness. Laboratories may also receive joint fluid, pleural fluid, or other sterile site specimens from these patients.
Why do you need a Gram stain for meningitis?
Gram-positive bacteria retain the primary stain while gram-negative bacteria take the color of the counterstain. A Gram stain can also serve to assess the quality of a clinical specimen. The CSF should be properly centrifuged in order to obtain the sediment for the procedure.