Sir,
Diagnosis of brucellosis is still facing problems in both aspects of “clinical and Laboratory diagnosis”. Recent analysis report of brucellosis incidence indicates more than ten times higher frequency rate in the west, North-West, and North-East than the average rate of the country (38.67/100 000).[1] This high rate in endemic areas definitely proves problems in diagnosis. Classical methods could not alone meet clinicians’ demands, especially blood culture that may rarely be positive in the absence of positive serological procedures, although its use is necessary in some cases. However, Brucella species can be isolated from other specimens with high efficiency such as bone marrow, cerebrospinal fluid, and so on since the relatively high concentration of Brucella in these specimens. Improving biphasic culture media by adding enriched supplements or preparing selective blood culture media has not been able to considerably increase the isolation rate. The reported identification rates are mostly too low with about 2% in clinical laboratories.[2,3,4] Besides all drawbacks, long incubation time is another problems, carrying up to six weeks before rejected as negative.[5]
Some references recommend blood specimens to be pretreated by applying lysis centrifugation or clot culture technique to enhance the efficiency of isolation. In these methods, blood cell disrupted and lysed by sterile distilled water followed centrifugation or clot disrupted by shaking the tube-containing glass beads. These methods may increase the sensitivity, but it is not practical in routine work because of its requirement for standard biosafety level moreover may increase the risk of contamination of the specimens.[2] Facility assessment has also revealed biosafety status has not possessed all of the required biosafety elements.[6] With introducing of automated blood culture systems to the diagnostic laboratories, requisite time for detection has been significantly reduced so that Brucella can be detected in the blood specimens of infected patients after 4 days or less with significantly higher rate than routine method. Some of the current-applying systems are BACTEC and BacT/Alert which continuously monitor the CO2 release of potentially growing microorganisms and BACTEC Myco/Flytic system which integrates lytic activity and automation.[7,8] At present, Health Center Laboratories are applying only classic serology tests “agglutination-based methods” not other procedures in all over the country. Physicians are introducing patients to the laboratory of either hospitals or private diagnostic sectors for isolations in the necessary cases.
In conclusions, based on surveillance reports, the current situation is still involving various difficulties causing reduction of efficiency. Therefore, this procedure is not cost effective in all over the country. It is strongly recommended to have some national referral laboratories in those areas with a high incidence rate at least. These referral laboratories must be enabled to apply all available methods, including a new automated system in parallel with routine laboratories. All those extremely suspected cases having negative results expected to be sent for these laboratories for further experiments. These centers should enable to do all diagnostic methods; serological tests (agglutination-based ones, ELISA, Brucella immunocapture, and atc), molecular technique, and culture.[8] Obviously equipped these laboratories with automated system provide satisfactory results for the blood specimens.
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Conflicts of interest
There are no conflicts of interest.
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