Research Interests:
Mutations associated with rifampicin (RIF) resistance in two regions of the rpoB gene were studied by line probe (INNO-LiPA Rif. TB) assay (LiPA) and/or DNA sequencing in 32 RIF-resistant and 21 RIF-susceptible Mycobacterium tuberculosis... more
Mutations associated with rifampicin (RIF) resistance in two regions of the rpoB gene were studied by line probe (INNO-LiPA Rif. TB) assay (LiPA) and/or DNA sequencing in 32 RIF-resistant and 21 RIF-susceptible Mycobacterium tuberculosis strains isolated from 53 tuberculosis patients in Kuwait. The LiPA identified all susceptible strains as RIF sensitive, and the DNA sequences of the 81bp rifampicin resistance-determining region (RRDR) and the N-terminal region of the rpoB gene from five isolates were identical to the wild-type sequences from M. tuberculosis H(37)Rv. The LiPA identified 24 of 32 (75%) phenotypically documented RIF-resistant M. tuberculosis isolates as RIF resistant, with specific detection of mutation in 19 isolates, whilst 8 strains were identified as RIF susceptible. DNA sequencing of the RRDR confirmed the results for the 19 RIF-resistant isolates and identified precise mutations in five isolates for which specific base changes could not be determined by LiPA, as...
Research Interests:
Most mycobacterial infections are still caused by Mycobacterium tuberculosis complex (MTC) strains; however, infections by non-tuberculous mycobacteria (NTM) are increasing, particularly among immunocompromised patients. Conventional... more
Most mycobacterial infections are still caused by Mycobacterium tuberculosis complex (MTC) strains; however, infections by non-tuberculous mycobacteria (NTM) are increasing, particularly among immunocompromised patients. Conventional species-specific identification and proper patient management are delayed due to the slow-growing nature of mycobacteria. We have developed a multiplex PCR (mPCR) targeting the oxyR-ahpC intergenic region and rpoB gene for direct detection and differentiation of clinical isolates as MTC or NTM in primary culture. Two amplicons of 473 bp and 235 bp from MTC members and a single amplicon of 136 bp from NTM are expected. The mPCR was developed using several mycobacterial species and was evaluated by testing extracted DNA from liquid cultures, flagged as positive for bacterial growth, of 100 consecutive mycobacterial isolates. The results were validated by DNA sequencing of the species-specific 16S-23S internal transcribed spacer (ITS) region. The mPCR with...
Research Interests: Medical Microbiology, Applied microbiology, Multidisciplinary, Food Microbiology, Biological Sciences, and 22 moreKuwait, Tuberculosis, Humans, Mycobacterium tuberculosis, Escherichia coli, Mycobacterium, Animals, Meat, Bacteria, Microbial genetic and drug resistance, Polymerase Chain Reaction, Plasmids, Cattle, Prevalence, Anti-Bacterial Agents, Chickens, Time Factors, Swine, Ciprofloxacin, Species Specificity, Sensitivity and Specificity, and Escherichia Coli Infections
Research Interests:
Research Interests:
Among 452 Xpert MTB/RIF (Xpert) and MGIT 960 system (MGIT) positive samples, 440 and 10 Mycobacterium tuberculosis were detected as rifampin-susceptible and rifampin-resistant, respectively. Two rifampin-susceptible isolates by MGIT were... more
Among 452 Xpert MTB/RIF (Xpert) and MGIT 960 system (MGIT) positive samples, 440 and 10 Mycobacterium tuberculosis were detected as rifampin-susceptible and rifampin-resistant, respectively. Two rifampin-susceptible isolates by MGIT were rifampin-resistant by Xpert. rpoB sequencing identified a silent (CTG521TTG) mutation in one and a missense (GAC516TAC) mutation in another isolate. Detection of rifampin resistance is imperfect with both, Xpert and MGIT. Any discordant rifampin resistance should be confirmed by sequencing of the rpoB gene.
Research Interests:
Research Interests:
Research Interests:
The presence of ACC and other mutations at codon 315 in the katG gene was detected by PCR amplification followed by restriction fragment length polymorphism (PCR-RFLP) generated with restriction enzymes Msp I and MspA1 I in 37... more
The presence of ACC and other mutations at codon 315 in the katG gene was detected by PCR amplification followed by restriction fragment length polymorphism (PCR-RFLP) generated with restriction enzymes Msp I and MspA1 I in 37 isoniazid-resistant and 22-susceptible Mycobacterium tuberculosis isolates from Kuwait obtained in 2001. The mutation AGC to ACC was detected in 22 (60%) isolates while any mutation at codon 315 of the katG gene was present in 24 (65%) of 37 isoniazid-resistant isolates. The typing studies showed that majority of the isolates carrying mutations at codon 315 exhibited unique DNA banding patterns. The results were extended by additional analysis of 67, 28 and 17 isoniazid-resistant and 18, seven and six-susceptible M. tuberculosis isolates from Kuwait, Dubai and Beirut, respectively, that were analyzed previously for ACC mutation alone. These studies showed that one of 21, one of 10 and two of 11 isolates (all recovered from patients of Middle Eastern origin) with no AGC to ACC mutation from Kuwait, Dubai and Beirut, respectively, contained other mutations at codon 315 of the katG gene. None of the susceptible strains contained any mutation at codon 315. The PCR-RFLP with MspA1 I that detects all mutations at codon 315, compared with Msp I that detects only ACC mutation, identified more isoniazid-resistant strains with mutations at codon 315 in the katG gene. The data also showed that mutations other than AGC to ACC at codon 315 in the katG gene occur frequently in M. tuberculosis isolates recovered from Middle Eastern patients and should be incorporated in a rapid screen for the detection of mutations for isoniazid-resistance in the katG gene from this ethnic group.