[Evaluation of mycobacterial microscopy and culture results of Sureyyapasa Chest Diseases and Chest Surgery Training and Research Hospital: A 3-year analysis].

INTRODUCTION

Effective diagnosis of tuberculosis is of great importance for transmission control and treatment success. The purpose of this study is to evaluate microscopic examination results of Ehrlich-Ziehl Neelsen (EZN) and Auramine-Rhodamine staining methods and automated BACTEC MGIT 960™ system and Löwenstein-Jensen (L-J) culture results of various clinical samples in the light of recent data from the world and Turkey.

MATERIALS AND

METHODS

Specimens that were sent from various clinics to Sureyyapasa Chest Diseases and Chest Surgery Training and Research Hospital Microbiology Laboratory from January 2012 to December 2015 were evaluated retrospectively.

RESULT: From a total of 62456 samples; 60923 (97.5%) were pulmonary and 1533 (2.5%) were non-pulmonary samples, especially pleura. 2853 (4.6%) Acid-resistant bacilli (ARB) positivity was detected and mycobacterial culture positivity was in total 12.2%. 7076 (93%) and 535 (7%) mycobacteria other than tuberculosis (MOTT) strains were isolated. In 356 specimens the cultures were negative in despite the positive ARB results. Considering mycobacterial culture as the gold standard; the sensitivity, specificity, positive and negative predictive values of ARB microscopy were 32.8%, 99.4%, 87.5% and 91.4%, respectively. The contamination rates in total were within acceptable limits being 2.7% for L-J and 3.8% for MGIT.

CONCLUSIONS

Analysis of our data indicated that the sensitivity of microscopy is low and it should be evaluated together with the mycobacterial culture to rule out tuberculosis infection. With the use of fluorescent staining and also L-J and MGIT broth together for routine culture since 2013; ARB false negativity rate was observed to fall to 51.7% from 74.1% compared to the years. The follow-up of data such as the sensitivity of microscopy, culture positivity, false-positivity and false-negativity rates and contamination values is of great importance in terms of assessing compliance with laboratory quality standards and contributing to the surveillance studies.