5340. Bacterial culture. Nose. Antimicrobial resistance profile with MIC (if microflora is detected)

Bacteriological culture allows assessment of the qualitative and quantitative composition of the nasal mucosal microflora and identification of etiologically significant bacterial pathogens causing infections such as rhinitis, rhinosinusitis, and sinusitis.

If pathogenic microorganisms are detected, an antibiotic susceptibility test with MIC (minimal inhibitory concentration) is performed to determine the effectiveness of antibacterial therapy.

Automated identification of microorganisms is performed using MALDI-TOF mass spectrometry on the MALDI Biotyper sirius IVD System analyzer (Bruker, Germany).

Normally, the nasal mucosa is colonized by commensal microorganisms that do not cause disease and even perform a protective function. These include coagulase-negative staphylococci (Staphylococcus epidermidis), nonpathogenic corynebacteria (Corynebacterium spp.), Neisseria spp., Micrococcus spp., and Lactobacillus spp.

Opportunistic microflora refers to microorganisms that, under certain conditions (immune suppression, viral infection, mucosal trauma), can cause inflammation. The most common are Staphylococcus aureus, Streptococcus pneumoniae, S. pyogenes, Haemophilus influenzae, Moraxella catarrhalis, Enterobacteriaceae, Pseudomonas aeruginosa, and Candida spp.

Bacteriological examination is performed to detect pathogens or carriage of clinically significant microflora for epidemiological control. The sample is collected with a sterile swab from the nasal passages, mainly from the middle turbinate or the posterior part of the nose – areas where pathogens are most likely to localize.

The number of colony-forming units (CFU) is a critical parameter for differentiating between carriage and active infection. During bacteriological analysis, special attention is paid to the quantitative assessment of microbial growth:

• <10³ CFU/ml indicates carriage, low probability of infection.
• 10³–10⁴ CFU/ml suggests a conditionally significant concentration requiring clinical attention.
• 10⁴–10⁵ CFU/ml – suspected infectious process.
• >10⁵ CFU/ml – high probability of active bacterial infection.

Interpretation of results is always carried out in the context of the clinical picture – the presence of symptoms, comorbidities, and immune status.

When etiologically significant bacteria are detected, an antibiotic susceptibility test is performed, including the determination of the minimal inhibitory concentration (MIC). This allows confirmation of bacterial etiology, selection of effective antibacterial therapy, and assessment of treatment effectiveness.

Interpretation of results is performed according to international standards (EUCAST and CLSI), ensuring accuracy and clinical relevance.

In case of a positive result, self-treatment is not recommended. It is necessary to consult a physician for clinical evaluation and appropriate therapy.

Patients with immunodeficiency, oncologic pathology, or post-transplantation.

Pregnant women – in cases of suspected carriage of pathogenic microflora.

Young children – in cases of suspected bacterial colonization of the nasopharynx.

Recommended in the following cases:

• Acute and chronic inflammatory ENT diseases: rhinitis, sinusitis, adenoiditis, pharyngitis, tonsillitis.
• Frequent recurrences of upper respiratory tract infections.
• Suspected bacterial etiology of symptoms when empirical therapy is ineffective.
• Preparation for surgical intervention in the nasal or nasopharyngeal area (adenotomy, tonsillectomy).

Epidemiological indications:

• Detection of Staphylococcus aureus carriage, including MRSA.
• Screening of healthcare workers, childcare staff, and food service employees.
• Examination of contacts in infection outbreaks (diphtheria, meningococcal infection).
• Preventive screening before hospitalization (especially in oncohematology, intensive care, and neonatal units).

• Various types of biological material depending on the test