Bacterioscopic examination of pleural fluid and pericardial fluid

Bacterioscopic examination of pleural fluid includes staining of smears according to Ziehl-Neelsen. The appearance of tuberculosis bacilli in pleural fluid is the most reliable sign of pleural tuberculosis. Mycobacteria are found in exudate in tuberculous pleurisy relatively rarely. If a tuberculous process in the pleura is suspected, but with a negative bacterioscopic examination, a bacteriological examination of the pleural fluid for Mycobacterium tuberculosis is necessary.

The detection of tuberculosis bacilli in pericardial fluid is the most reliable sign of pericardial tuberculosis. Tuberculosis mycobacteria are found in the exudate relatively rarely in tuberculous pericarditis.

Bacterioscopic examination of pleural fluid and pericardial fluid is a fairly simple but effective method for identifying tuberculosis, as well as anaerobic or aerobic bacteria using microscopes of various modifications. Like any other study of serous cavity fluids, bacterioscopic examination of pleural fluid and pericardial fluid helps solve the following problems:

• Determination of the main causative agent of the pathology;
• Exclusion of a certain group of mycobacteria;
• Assessment of the degree of bacterial infection of a particular serous environment.

In addition, bacterioscopy is sometimes of decisive importance for the diagnosis of serious pathologies, when gonococci, pneumococci and other bacteria of this type, anaerobic microorganisms, tuberculosis bacilli are found in the puncture material (this is how the material for analysis is obtained), pericardial or pleural exudate. Timely determination of the type of pathogen helps to clarify the cause, make a more accurate diagnosis, and therefore begin effective treatment.

Bacterioscopic examination of pleural fluid and pericardial fluid is carried out using the method of staining the material - smears or sediment of liquids. In bacterioscopy of pleural material, as well as for studying pericardial fluid, the Ziehl-Neelsen staining method is often used. This method is called direct, since it does not require bringing the material to a homogeneous consistency (homogenization) and any other processing. Bacterioscopic examination of pleural fluid and pericardial fluid as microscopy of the material has existed for over a century. Bacterioscopy allows you to quickly identify almost all types of aerobic bacteria (microorganisms that reproduce only in the presence of oxygen), as well as those that die in the air - anaerobic.

Also, bacterioscopic tests determine all acid-resistant microorganisms – mycobacteria, which are also abbreviated as ARB (acid-resistant bacteria).

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How is bacterioscopic examination of pleural fluid and pericardial fluid performed?

Bacterioscopy is performed using a special microscope that shows microorganisms stained with carbolic dye. All results will be expressed in quantitative terms.

KUB, i.e. those bacteria that are revealed by bacterioscopy, differ from their "brothers" in that their cell wall can quickly take on the color of the environment and retain it. This can be explained by the high content of lipids in the cell membrane of microorganisms. Bacteria absorb and adsorb carbol fuchsin, and so intensively that the color cannot be removed by either alcohol or acids. The stained bacteria are subsequently treated with methylthioninium chloride - methylene blue. Under a microscope, bacteria are visible as red elongated rods against the background of blue. The method, named after its developers - Ziehl-Nielsen, is very specific and effective, despite its simplicity. Nevertheless, it should be taken into account that such a technique is less indicative than cultural methods, in addition, not all materials are suitable for research according to Ziehl-Nielsen.

Since the end of the last century, more precisely since 1989, many laboratories have been using a more advanced and informative method of bacterioscopy. Bacterioscopic examination of pleural fluid and pericardial fluid is often carried out using fluorescence microscopy. This method is based on the same properties of bacteria to firmly retain color. For the fluorescence method, other dyes are used that provoke fluorescence (glow) of bacteria under ultraviolet light.

Any pulmonary pathologies, pericarditis require careful and detailed diagnostics, since it is necessary to find out the etiology of these diseases and determine the presence and type of harmful infections. Therefore, bacterioscopic examination of pleural fluid and pericardial fluid, as a rule, implies the use of all modern microscopic methods and is one of the components of general diagnostic measures.