Culture for anaerobic bacteria

Seeding for anaerobic bacteria

Anaerobic bacteria are a group that includes many generas and speciess of microorganisms thatre only able to thrive in the absence of oxygen – they die even minutes after being exposed to it. Somere anaerobes normally live in small numbers in places such as skinry crevices, nose, dental plaque, gum pockets, throat, vagina, without causing infection. Injury to these locations (mechanical damage to the epidermisr or mucosa), allows them to penetrate almost all areasof the body thatre physiologically sterile (contain no bacteria). If pathogens enter body fluid or deep tissue that&oac;re poorly oxygenated, an infection can develop.

Patients who are immunocompromised (on anticancer therapy, steroids, HIV positive), with a history of trauma wounds (cuts, bites, puncture wounds), oral, abdominal or pelvic surgery, invasive procedures (catheterization, dialysis) are particularly at risk for infection due to anaerobes. Characteristic of infections with anaerobic flora is the formation of abscesses, necrosis, gangrene in soft tissues. If the bacteria pass from the site of primary invasion into the blood, with it they can spread to any internal organ and cause a rapid immune response of the body in the form of sepsis (sepsis) with an unpredictable course.

Because of the above, early detection and rnisation of anaerobic infections with other conditions giving similar complaints is of utmost importance. Blood cultures for aerobic and anaerobic bacteria should always be performed, for patientswith rapidly deteriorating general condition and fever of unknown cause.

Screening for anaerobic bacteria – when to perform?

The test is ordered to diagnose the cause of rl infections, often running with uncharacteristic symptoms, on suspicion that they may be caused by anaerobic bacteria. Indications for culture are the existence of severe local infections (including wounds, non-healing, unresponsive to treatment with standard antibiotics); inflammation of deep tissues, including bone marrow and bone; abscesses in unusual locations (within the ms, lungs, liver, abdominal cavity, pelvis, minor pelvis, around the apicesof teeths, tonsilss). In addition, it can always be performed for post-treatment follow-up.

The material for the test can be any body fluid (urine, blood, mspinal fluid, pleural fluid, peritoneal fluid), a swab from a wound or genital organs, a prb of necrotic tissue, an aspirate taken from the bone marrow, or fluid contents from inside an abscess.

The specimen should be collected by qualified medical personnel, as anaerobic bacteria are isolated and stored in a special wayb (protected from oxygen). They are cultured longer and in different media than aerobic bacteria.

Screening for anaerobic bacteria – who should do it?

People with symptoms that may suggest an infection caused by anaerobic bacteria:

• wound infections: bl, swelling, purulent discharge, unpleasant odor, different color of the lesion area,
• infections in the mouth and throat: gingivitis and periodontitis, prchnica, perianal abscesses, white plaque on the tonsils,
• infections in the abdominal cavity: ble and enlargement of the abdominal girth, muscular defenses,
• gynecologic infection: abnormal vaginal discharge, pressure in the lower abdomen,
• sepsis: chills, fever of undetermined origin, hypotension, accelerated heart rate, nausea and vomiting, disturbance of consciousness.

Screening for anaerobic bacteria standard

• negative culture (-)

It means that no bacterial growth was observed on the culture plate – nevertheless, if characteristic symptoms persist, this does not exclude the existence of anaerobic infection. Due to the need for exceptional conditionsfor the growth of pathogensthe test can be repeated several times to increase the reliability of the results.

• positive culture (+)

It means that bacterial growth was observed on the culture plate – nevertheless, a positive result does not guarantee that the cultured strain is the cause of the patients symptoms, as the prevalence of anaerobic bacteria in the body's tissues and body fluids is high. The decision to initiate antibiotic therapy should be made after excluding other causes of infection and in conjunction with information about the patient's current condition, results of other tests (including imaging).