Dear Samarjit,

Please read the following text:

Bacteremia (also bacteraemia) is the presence of bacteria in the blood. Blood is normally a sterile environment,[1] so the detection of bacteria in the blood (most commonly accomplished by blood cultures) is always abnormal.

Bacteria can enter the bloodstream as a severe complication of infections (like pneumonia or meningitis), during surgery (especially when involving mucous membranes such as the gastrointestinal tract), or due to catheters and other foreign bodies entering thearteries or veins (including during intravenous drug abuse).

Bacteremia can have several consequences. The immune response to the bacteria can cause sepsis and septic shock, which has a relatively high mortality rate. Bacteria can also use the blood to spread to other parts of the body (which is called hematogenousspread), causing infections away from the original site of infection. Examples include endocarditis or osteomyelitis. Treatment is with antibiotics, and prevention with antibiotic prophylaxis can be given in situations where problems are to be expected.

Diagnosis

Bacteremia is most commonly diagnosed by blood culture, in which a sample of blood is allowed to incubate with a medium that promotes bacterial growth. Since blood is normally sterile, this process does not normally lead to the isolation of bacteria. If, however, bacteria are present in the bloodstream at the time the sample is obtained, the bacteria will multiply and can thereby be detected. Any bacteria that incidentally find their way to the culture medium will also multiply. For this reason, blood cultures must be drawn with great attention to sterile process. Occasionally, blood cultures will reveal the presence of bacteria that represent contamination from the skin through which the culture was obtained. Blood cultures must be repeated at intervals to determine if persistent — rather than transient — bacteremia is present.

Ultrasound of the heart is recommended in all those with bacteremia due to Staphylococcus aureus to rule out infectious endocarditis.

How is Sepsis Diagnosed?

If you have symptoms of sepsis, your doctor will order tests to make a diagnosis and determine the severity of your infection.

One of the first tests is a blood test. Your blood is checked for complications like:

infection

clotting problems

abnormal liver or kidney function

decreased amount of oxygen

an imbalance in minerals called electrolytes that affect the amount of water in your body as well as the acidity of your blood

Depending on your symptoms and the results of your blood test, your doctor may order other tests, including:

a urine test (to check for bacteria in your urine)

a wound secretion test (to check an open wound for an infection)

a mucus secretion test (to identify germs responsible for an infection)

If your doctor can’t determine the source of an infection using the above tests, your doctor may order an internal view of your body using one of the following:

X-rays to view the lungs

computed tomography (CT) scans to view possible infections in the appendix, pancreas, or bowel area

ultrasounds to view infections in the gallbladder or ovaries

magnetic resonance imaging (MRI), which can identify soft tissue infections

Sepsis can quickly progress to septic shock and death if it is left untreated. Doctors use a number of medications to treat sepsis, including:

antibiotics via IV to fight infection

vasoactive medications to increase blood pressure

insulin to stabilize blood sugar

corticosteroids to reduce inflammation

painkillers

Severe sepsis may also require large amounts of IV fluids and a respirator for breathing. Dialysis might be necessary if the kidneys are affected. Kidneys help filter harmful wastes, salt, and excess water from the blood. In dialysis, a machine performs these functions.

In some cases, surgery may be needed to remove the source of an infection. This includes draining a pus-filled abscess or removing infected tissue.

http://www.healthline.com/health/sepsis#Treatment7

Holland, TL; Arnold, C; Fowler VG, Jr (1 October 2014). "Clinical management of Staphylococcus aureus bacteremia: a review.". JAMA 312 (13): 1330–41. doi:10.1001/jama.2014.9743. PMID 25268440.

Hoping this will be helpful,

Rafik

Hello Rafik Karaman,

As you written that it is possible to get contamination in blood culture due mentioned possibility by you, specially during the time of blood collection. But the blood collection for detection of infection in a SEPSIS we can't approaches the patient every time.So as mentioned in paper

International sepsis definitions conference. 2001 SCCM/ESICM/ACCP/ATS/SIS international sepsis definitions conference,

what is the possibility of getting positive result for detection of bacterial infection by conducting test for LPS, bacterial DNA. ..

Samarjit

Blood test for Gram stain and other stains plus culture and sensitivity to see the response to antibiotic/s if culture is positive.

Blood culture is the gold standart for identifing presence of sepsis.

Blood culture is the gold standart for identifing presence of sepsis.

Blood culture is the gold standart for identifing presence of sepsis.

PCR is a new technique but requires patient's blood or urine

PCR is a new technique but requires patient's blood or urine

I agree with the opinion of Preet Shah. Procalcitonin (PCT) has already been used to identify infection rapidly. It is also considered that the role of blood culture is mainly not for the rapid indentification of infection but for the accurate selection of antibiotics because blood cultue has more time-lag than PCT.

blood culture is the gold standart.

will be the blood agar test is sufficient to determine the infection in blood?

How do I diagnose sepsis (being an infection with systemic features and evidence of organ impairment)? - this is a clinical/laboratory diagnosis which combines clinical features of inflammation (fever, tachycardia, diaphoresis, apparent focus of infection) with laboratory parameters (white cell count, neutrophil count, C-reactive protein, pro-calcitonin), and where appropriate radiological evidence of a focus (CXR -pneumonia, CT abdomen -intra-abdominal collection etc...).  Ideally one also takes appropriate samples for microbiological testing, either by culture, molecular testing or serology.  The firmest diagnosis is based on a combination of clinical, laboratory, radiological and microbiological results, where all point in the same direction.  If you are specifically interested in blood stream infections, then detection of the organism of interest in the blood is the key, as blood stream infections do not generally have focal signs  (that being said a pure 'bacteraemia' without primary source is pretty rare - most bacteraemias arise from a reservoir of infection such as the lung, abdomen/renal tract, intravascular line or heart valve).

The problem is that no single one of these tests and clinical features is either very sensitive nor very specific for sepsis - they may be absent in the presence of sepsis and equally may be present when there is no sepsis.  This is why it requires an integration of multiple data sources to make the diagnosis.  PCT has been touted as a specific and sensitive test for bacterial infection, however it is not sensitive to all bacterial infections and fails to account for non-bacterial infections - its best use is probably in helping limit antibiotic therapy duration.

There are novel diagnostics either close to or on the market - the wider range of molecular diagnostics will make it easier to detect organisms which are hard to culture (due to either innate difficulty of culturing, or pre-test use of antibiotics which inhibit growth).  Markers of immune status, either soluble cytokines or cell surface markers are also touted, although the stereotyped response to bacterial and sterile insults suggests to me that these will suffer from the same problems as existing laboratory measures of infection/inflammation.

There is no single specific test  for confirmation of blood infection. The confirmatory test will be demonstration of a micro-organism in blood but before that, there should be some clinical findings suggestive of  any infection. Many time infection is there in the body but can not be demonstrated in blood and patient is having all the findings suggestive of infection. If some patient is having any symptoms and signs of infection, CBC, Neutrofil count, CRP, and prolactin along with microbiological lab test and radiological test for confirmation  of infection are of paramount importance.  

There is no single specific test  for confirmation of blood infection. The confirmatory test will be demonstration of a micro-organism in blood but before that, there should be some clinical findings suggestive of  any infection. Many time infection is there in the body but can not be demonstrated in blood and patient is having all the findings suggestive of infection. If some patient is having any symptoms and signs of infection, CBC, Neutrofil count, CRP, and prolactin along with microbiological lab test and radiological test for confirmation  of infection are of paramount importance.