ABSTRACT
This study reviews the resistance patterns of Mycobacterium tuberculosis complex [MTBC] isolates obtained from 578 patients [369 Saudi and 209 non-Saudi] in the period between the first of January 2001 and the end of December, 2006. Four hundred thirty nine of the isolates were from respiratory sources while the remaining [139] were from non-respiratory sites. The isolates were tested for their susceptibility to isoniazid [INH], rifampin [RIF], ethambutol [EMB], streptomycin [SM] and pyrazinamide [PZA] using the BACTEC MGIT 960 system [Becton Dickinson Medical Systems, Sparks, MD]. The turnaround time for antimicrobial susceptibility testing [to SM, INH, RIF and EMB] ranged from 4.0 to 13.0 days with an average of 8.3 +/- 2.1 days. The turnaround time for susceptibility testing to PZA ranged from 4.04 to 14.25 days with an average of 7.2 +/- 2.2 days. The percentages of resistance to anti-tuberculosis drugs in Saudi and non-Saudi patients respectively were: 25.5% and 35.9% for INH; 13.6% and 21.1% for RIF, 18.4% and 23.4% for SM, 19.5% and 15.3% for EMB, 19.2% and 9.7% for PZA and 10.6% versus 16.7% for multidrug resistant [MDR] TB [resistant at least to INH and RIF]. Resistance to INH and RIF was significantly higher in non-Saudi patients [p < 0.05]. The percentages of resistance to anti-tuberculosis drugs in respiratory samples from Saudi and non-Saudi patients respectively were: 25.5% and 37.6% for INH; 15.0% and 24.2% for RIF, 21.5% and 25.5% for SM, 20.1% and 15.8% for EMB, 16.7% and 10.0% for PZA and 12.4% versus 19.4% for MDRTB. Regarding non-respiratory samples, the percentages of resistance to anti-tuberculosis drugs from Saudi and non-Saudi patients respectively were: 25.3% and 29.5% for INH; 9.5% and 9.1% for RIF, 9.5% and 15.9% for SM, 17.9% and 13.6% for EMB, 25.0% and 8.3% for PZA and 5.3% versus 6.8% for MDR-TB. The overall percentages of resistance to anti-tuberculosis drugs in respiratory and non-respiratory samples respectively were: 30.1% and 26.6% for INH; 18.5% and 9.4% for RIF, 23.0% and 11.5% for SM, 18.5% and 16.5% for EMB, 13.5% and 19.4% for PZA and 15.0% versus 5.8% for MDR-TB. Differences were statistically significant only in cases of RIF, SM and MDR-TB. In general, resistance was higher in respiratory samples obtained from non-Saudi patients. These variations may be mainly due to the differences in the prevalence of MTBC variants between Saudi and non- Saudi patients
ABSTRACT
Phenytoin is a widely used anticonvulsant drug, the chronic administration of which maybe associated with several drug interactions. This study aims at testing the presence of an interaction between phenytoin and two of the newly used neuromuscular b lockers [NMBs], namely rocuronium and cisatracurium. 96 male albino rats were used, half of which were treated daily with oral phenytoin, 100 mg/Kg for four weeks, while the rest were given the vehicle and served as controls. Thirty six animals from each group were used for in vivo administration of three different doses of each tested neuromuscular blacker [0.5, 1.0 and 2.0 mg/Kg in case of rocuronium and 0.4, 0.8 and 1.6 mg/Kg in case of cisatracurium] and twelve were used to obtain phrenic nerve diaphragm preparations for evaluation of in vitro actions of different concentrations of the tested NMBs [0.25, 0.5 and 1.0 micro g/Kg in case of rocuronium and 0.5, 1.0 and 2.0 micro g/Kg in case of cisatracurium]. With both NMBs, there was a significantly shorter duration of paralysis and a significantly shorter recovery index following phenytoin treatment. This was true for all studied doses. The effect of all tested concentrations of rocuronium and cisatracurium on the response to phrenic nerve stimulation was significantly less in preparations obtained from phenytoin treated animals with an almost parallel rightward shift of concentration response curves. Results of this study suggest a dynamic background for the resistance commonly encountered with NMBs among patients on chronic phenytoin therapy. A kinetic type of interaction, however can not be excluded. It is thus recommended that more frequent or continuous monitoring should be considered in patients known to be on chronic anticonvulsant therapy even those receiving NMBs like cisatracurium, with a predominantly organ-independent elimination