Evaluation of the Kudoh swab method for the culturing of Mycobacterium tuberculosis in rural areas

Objective: To compare the simple, swab 'Kudoh method' for culturing Myobacterium tuberculosis from sputum samples, to the standard Petroff digestion-decontamination procedure. The Kudoh method, which requires no centrifugation and takes only 4-5 min per sample, was also evaluated for its performance in a rural setting. Methods: Two hospital laboratories in Caracas, Venezuela processed 314 sputum samples, in parallel, with both methods. Separately, sputum specimens were cultured with the Kudoh swab method in a field environment with minimal laboratory facilities. Results: In the hospital laboratories, the sensitivity of the Kudoh swab method was comparable to that of the standard Petroff culture procedure. The swab method also performed satisfactorily in the field, improving the diagnostic sensitivity by 21% over microscopic examination alone. Conclusion: The Kudoh swab method is an acceptable alternative for culturing mycobacteria that is particularly suitable for rural laboratories lacking adequate infrastructure for the Petroff method.