EVALUATION OF THE ESP CULTURE SYSTEM-II FOR RECOVERY OF MYCOBACTERIA FROM BLOOD SPECIMENS COLLECTED IN ISOLATOR TUBES

The reliability of the ESP Culture System II (ESP II; AccuMed Internat ional, Westlake, Ohio), a continuously monitoring, nonradiometric myco bacterial culture system, for recovery of mycobacteria from sediments of blood collected in an Isolator tube was evaluated by comparing its performance to inoculation of the sediment onto Middlebrook 7H11/7H11 selective biplates. Of1,704 blood specimens, 73 (4.3%) were positive f or mycobacteria (68 Mycobacterium avium complex and 5 M. tuberculosis) , Fifty-three specimens were positive by both methods; 13 were positiv e by ESP II only, and 7 were positive by Middlebrook agar only (chi sq uare = 1.8; P > 0.05). The mean times to positivity were 15.6 days for ESP II and 19.0 days for Middlebrook agar (P < 0.01). The time to det ection was the same for 13 specimens; ESP XI was positive first for 33 , and agar plates were positive first for 7. ESP II allowed recovery o f more mycobacteria (90.4% of all isolates versus 82.2% for Middlebroo k agar) from sediments of blood specimens collected in Isolator tubes, and it provided significantly faster detection than did Middlebrook p lates.