Abstract
Abstract Background: The emergence and spread of drug resistant and multidrug resistance are a global health problem. The susceptibility patterns of M. tuberculosis isolates against anti-tuberculosis drugs forms an important aspect of the control programs at the local level. The aim of this study was to determine the pattern of the susceptibility of drugs to M. tuberculosis isolates from patients with pulmonary tuberculosis in Tripoli, Libya. Methods: Drug Susceptibility Test (DST) was performed on 261 isolates of M. tuberculosis by BD BACTEC MGIT 960 SIRE system. The drugs tested were: isoniazid (INH), rifampicin (RIF), streptomycin (SM) and ethambutol (EMB). Results: All isolates (261) were confirmed as M. tuberculosis complex and showed different resistance patterns: 8.8% to INH; 5.7% to RIF; 8.8% to SM; and 9.0% to EMB. Rifampicin was the lowest detected resistance first-line antibiotics studied. One drug resistant was observed in 18.0%; 3.8% were resistant to two drugs; and 2.3% were resistant to a combination of three-drugs. Of the total 261 cases, 217 were designated as new untreated patients and 44 as previously treated patients. In terms of resistance to any drug, there was a significant difference between the two categories (P<0.014). However, there was no significant difference between new and previously treated patients in relation to one drug resistant (P=0.4). Meanwhile, there was a significant difference in relation to two drug resistant (P<0.005), Nine (20.5%) of the isolates designated multi-drug resistant (MDR) were obtained only from previously treated patients. None of newly treated cases had isolates resistant to three-drugs nor MDRs. Conclusion: This preliminary study indicated the low prevalence of drug resistance M. tuberculosis (MTB) among previously treated patients in Tripoli.