Description of Microbiological Analysis:

Carbapenem-resistant Enterobacteriaceae (CRE) represent a category of Gram-negative bacteria, such as Escherichia coli and Klebsiella pneumoniae, that have developed high-level resistance to carbapenem antibiotics. These drugs are often considered the “last line of defense” for treating multidrug-resistant infections. The resistance is typically driven by the production of carbapenemases—enzymes that dismantle the antibiotic molecule. Detecting CRE is a critical medical priority because these “superbugs” are associated with significant mortality rates and present major challenges for clinical management and hospital infection control.

What does the analysis represent?

• Purpose: To isolate live Enterobacteriaceae from a clinical specimen and confirm their phenotypic or genotypic resistance to carbapenem-class antibiotics.
• Main Application: Screening for asymptomatic colonization in high-risk patients (intensive care, oncology, or surgical units), diagnosing systemic infections like sepsis or pneumonia, and guiding targeted antimicrobial therapy.
• Method: Microbiological culture on specialized selective media containing carbapenems, followed by species identification (e.g., via MALDI-TOF) and confirmatory tests for carbapenemase production (such as the modified Carbapenem Inactivation Method or PCR).

Recommendations for the Test (General)

• Time: Specimen collection is performed based on clinical necessity, usually as soon as a resistant infection is suspected or upon hospital admission for screening.
• Fasting: For microbiological cultures (rectal swabs, urine, or sputum), dietary restrictions are generally not required.
• Rest: No specific physical rest is needed, but strict adherence to sterile collection protocols is mandatory.
• Specific Rules: The specimen must be collected prior to the initiation of new antibiotic therapy. If the patient is already on antibiotics, the laboratory must be notified, as the medication may suppress bacterial growth and lead to a false-negative result.

What can affect the results?

• Factors altering levels: Ongoing antimicrobial treatment; use of local antiseptics or lubricants at the collection site (e.g., for rectal swabs); contamination with skin flora during collection; and failure to maintain the cold chain or appropriate transport media during delivery to the laboratory.

When to take the test?

• Recommendations: The test is indicated when standard antibiotic therapy fails, during prolonged fever in a hospital setting, or as a mandatory screening for patients transferred from other healthcare facilities or those with a history of travel to endemic regions.
• Preparation: Rigorous hygiene of the collection site (especially for mid-stream urine samples) is essential to ensure the accuracy and purity of the bacterial growth.

How to interpret the results?

The interpretation of the obtained data is the exclusive responsibility of the physician. Under current healthcare regulations and legal frameworks regarding infectious disease reporting, a “Detected” result for CRE triggers mandatory institutional infection control protocols, including patient isolation. Clinically, a positive result signifies the presence of a highly resistant pathogen, necessitating a shift to “reserve” antibiotics. Only professional medical analysis can determine whether the detected strain represents active infection or asymptomatic colonization and which legal reporting requirements apply.

Possible further investigations

• Extended Antimicrobial Susceptibility Testing (AST): To identify sensitivity to novel drugs like ceftazidime-avibactam or colistin.
• Molecular Genotyping (PCR for KPC, NDM, VIM, OXA-48): To identify the specific genetic mechanism of resistance for epidemiological tracking.
• C-Reactive Protein (CRP) and Procalcitonin: To assess the severity of the systemic inflammatory response.
• Infectious Disease Consultation: To design a specialized, multifaceted treatment regimen.

When does the next step make sense?

If the CRE culture is positive, the results are used by the healthcare team to implement contact precautions and select specific, high-potency antimicrobial combinations. All clinical decisions and follow-up cultures are performed under strict medical supervision to ensure patient safety and prevent the horizontal transmission of the resistant strain within the facility.

👉If necessary, you can discuss the results of the analysis with a specialist, such as an gastroenterologist (Doctors – TAMC).