Case Study#4   1  2  3   4  5   6   7  8  9  10  11  12  13  14  15  16  17   Drug Susceptibility Testing Primary drugs (for M. tuberculosis) Bactec system Rifampin, Isoniazid, Streptomycin, Ethambutol, Pyrazinamide Secondary drugs Agar proportion method Disk diffusion method Growth control 3+ Control (1/100 dilution) 8 col Clarithromycin 15ug/ml 0 Doxycycline 6ug/ml 3+ Trimeth/Sulfa30ug/ml 3+ Cefoxitin 30ug/ml 13 col Tobramycin 8ug/ml 3+ Amikacin 6ug/ml 3+ Amikacin 30ug/ml 0 Ciprofloxacin 8ug/ml 3+ Disposition Final Interpretation Mycobacterium chelonae complex with susceptibility pattern consistent with Mycobacterium abscessus Susceptible only to Amikacin Clarithromycin