Prevalence of drug resistance in clinical isolates of tuberculosis from GCC: a literature review from January 2002 to March 2013.

INTRODUCTION: The prevalence of drug resistance in clinical isolates of Mycobacterium tuberculosis from the Gulf Cooperation Council (GCC; Saudi Arabia, Qatar, Bahrain, Kuwait, Oman, United Arab Emirates [UAE]) countries was appraised using reports published between January 2002 and March 2013. METHODOLOGY: A total of 11,393 tuberculosis (TB) isolates from the GCC were studied through published literature and were analyzed statistically. RESULTS: Most of the isolates were resistant to isoniazid, followed by streptomycin, rifampin, ethambutol, and pyrazinamide. The highest prevalence rate of multidrug-resistant-TB (MDR-TB) was found in UAE (9.2%), followed by Kuwait (5.9%) and Saudi Arabia (4.3%). The overall MDR-TB prevalence rate was recorded as 4.0% in the entire GCC region. Automated linear modeling revealed that isoniazid resistance had a strong relationship with the prevalence of MDR-TB in all the GCC countries and was found to be the strongest predictor for MDR-TB. Interestingly, rifampicin resistance was significantly associated with the prevalence of MDR-TB in Oman, Kuwait, and Saudi Arabia, while isoniazid was identified for UAE. On the basis of a number of reports and isolates, the principal component analysis showed that, among all GCC member countries, the highest burden of TB was in Saudi Arabia and Kuwait, and maximum drug resistance was present in UAE. CONCLUSION: The study demonstrates that the prevalence of MDR-TB in GCC countries is almost equal to other developing and developed countries, and requires immediate attention for surveillance and control.

CspA encodes a major cold shock protein in Himalayan psychrotolerant Pseudomonas strains.

The major cold-shock protein (CspA) encoding gene cspA were detected in three Himalayan psychrotrophic Pseudomonad strains, by PCR amplification. Partial sequencing of three Pseudomonas strains cspA gene and BLAST search confirmed the high similarity with putative bacterial cspA gene and bacterial CspA protein. Bioinformatics analysis of these partial CspA amino acid sequences showed presence of putative conserved region for DNA/RNA-binding motifs RNP-1 and RNP-2. Protein homologies of all three bacterial CspA proteins belong to S1 like protein (Ribosomal protein S1-like RNA-binding domain). Presence of cspA gene and its high similarity with Bacillus cereus group demonstrating uniqueness of cspA gene in these Pseudomonas strains and suggesting strong evolutionary relationship between these two groups to survive in cold environments. Probable CspA protein expression levels were checked after cold shock (28°C to 4°C) and cold acclimation (4°C and 15°C) experiment. SDS-PAGE analysis revealed a small protein of approximate size of 7.5 kDa was expressed after cold shock (28°C to 4°C) and continuously over-expressed with the incubation time at cold temperature (4°C). Therefore it was predicted this protein would be product of cspA gene and suggesting this protein aids survival in Himalayan environments.

Cryotolerance strategies of Pseudomonads isolated from the rhizosphere of Himalayan plants.

The cold stress biology of psychrotrophic Pseudomonas strains isolated from the rhizosphere of Himalayan plants have been explored to evaluate their cryotolerance characteristcs. Pseudomonas strains were examined for stress metabolites, viz., exopolysaccharide (EPS) production, intracellular sugar, polyols and amino acid content, ice nucleation activity, and their freezing survival at -10 and -40°C, respectively. High freezing survival was observed for the Pseudomonas strains that were grown at 4°C prior to their freezing at -10 or -40°C. Increased EPS production was noticed when Pseudomonas strains were grown at lower temperatures, i.e., 4 and 15°C, in comparison with their optimal growth temperature of 28°C. All Pseudomonas strains showed low level of type-III class ice nucleation activity at -10°C after 96 h. Considerable differences were noticed in accumulated contents of various intracellular sugars, polyols, amino acids for all Pseudomonas strains when they grown at two different temperatures, i.e., 4 and 28°C, respectively. The unusual complement of stress protectants especially, raffinose, cysteine and aspartic acid that accumulated in the bacterial cells at low temperature was novel and intriguing finding of this study. The finding that raffinose is a key metabolite accumulated at low temperature is an exciting discovery, and to the best of our information this is first report ever signifying its role in bacterial cold tolerance.

Genetic and functional diversity among root-associated psychrotrophic Pseudomonad's isolated from the Himalayan plants.

Out of 534 psychrotrophic bacteria, 12 bacteria were selected on the basis of plant growth promoting activities at 4 °C and identified as Pseudomonas genus. These strains showed high level of genetic polymorphisms based on RAPD and rep-PCR fingerprinting. This genetic variability revealed that isolates belonging to same species were as high as the variability among different species. Further inoculation of these Pseudomonas strains significantly improves root/shoot biomass and nutrients uptake of lentil plant as compared to non-bacterized control after 40 days of seed showing. Agglomerative hierarchical clustering analysis of pot assay results revealed that genetically diverse strains showing the same prototype in functional parameter and representing diverse blueprint of plant growth promoting attributes. Results of present findings explain the huge beneficial microbial resources from root zone of hilly crops of Himalayan region that could be effectively exploited as bio-inoculums for cold climatic condition.

Alleviation of cold stress in inoculated wheat (Triticum aestivum L.) seedlings with psychrotolerant Pseudomonads from NW Himalayas.

Twelve psychrotolerant Pseudomonad strains were selected on the basis of various plant growth-promoting (PGP) activities at cold temperature (4°C). The effect of inoculation with Pseudomonad strains on cold alleviation and growth of wheat seedling at cold temperature (8°C) was investigated under greenhouse condition. Inoculation with Pseudomonad strains significantly enhanced root/shoot biomass and nutrients uptake as compared to non-bacterized control at 60 days of plant growth. Bacterization significantly improved the level of cellular metabolites like chlorophyll, anthocyanin, free proline, total phenolics, starch content, physiologically available iron, proteins, and amino acids that are sign of alleviation of cold stress in wheat plants. Increased relative water content, reduced membrane injury (electrolyte leakage), and Na(+)/K(+) ratio were also recorded in bacterized wheat plants. Electrolyte leakage and Na(+)/K(+) were found inversely proportional to plant growth at cold temperature. Statistical analysis of twenty-three measured parameters revealed that uninoculated control was under cold stress while eight bacterial strains were positively alleviating cold stress in wheat plants. Thus, the psychrotrophic Pseudomonad strains could effectively provide a promising solution to overcome cold stress, which is major factor hindering wheat productivity under cold climatic condition.