Detection of beta lactamase in sputum

Area of Science:

• Microbiology
• Clinical Diagnostics
• Biochemistry

Background:

• Beta-lactamase enzymes confer bacterial resistance to beta-lactam antibiotics.
• Accurate and rapid detection of beta-lactamase in clinical samples is crucial for effective treatment.
• Sputum analysis is vital for diagnosing respiratory tract infections.

Purpose of the Study:

• To develop a rapid, sensitive, and reproducible test for beta-lactamase detection in sputum.
• To correlate direct sputum test results with bacteriological culture findings.
• To confirm the source of beta-lactamase activity in sputum samples.

Main Methods:

• Investigated 120 sputum samples for beta-lactamase activity using the chromogenic cephalosporin nitrocefin.
• Employed sonication and incubation at 37°C, followed by albumin removal using blue sepharose beads.
• Compared direct sputum test results with aerobic and anaerobic bacterial cultures and isoelectric focusing (IEF).

Main Results:

• The nitrocefin test, after albumin removal, demonstrated 100% sensitivity and specificity for beta-lactamase detection in sputum.
• 16 out of 120 sputum samples were positive, yielding 19 beta-lactamase-producing bacteria.
• Isoelectric focusing confirmed that in 11 cases, the detected beta-lactamases originated from concurrent bacterial isolates.

Conclusions:

• Nitrocefin-based detection of beta-lactamase in sputum is a rapid, reproducible, highly specific, and sensitive diagnostic method.
• The test effectively identifies beta-lactamase activity directly in sputum samples.
• The study successfully linked beta-lactamase activity in sputum to specific bacterial isolates, aiding in infection source identification.