Prevalence of Extensively Drug Resistant Tuberculosis among Archived Multidrug Resistant Tuberculosis Isolates in Zimbabwe

We conducted a cross-sectional study of second line drug resistance patterns and genetic diversity of MDR-TB isolates archived at the BRTI-TB Laboratory, Harare, between January 2007 and December 2011. DSTs were performed for second line antituberculosis drugs. XDR-TB strains were defined as MDR-TB strains with resistance to either kanamycin and ofloxacin or capreomycin and ofloxacin. Strain types were identified by spoligotyping. No resistance to any second line drugs was shown in 73% of the isolates, with 23% resistant to one or two drugs but not meeting the definition of XDR-TB. A total of 26 shared types were identified, and 18 (69%) matched preexisting shared types in the current published spoligotype databases. Of the 11 out of 18 clustered SITs, 4 predominant (>6 isolates per shared type) were identified. The most and least abundant types were SIT 1468 (LAM 11-ZWE) with 12 (18%) isolates and SIT 53 (T1) with 6 (9%) isolates, respectively. XDR-TB strains are rare in Zimbabwe, but the high proportion of "pre-XDR-TB" strains and treatment failure cases is of concern. The genetic diversity of the MDR-TB strains showed no significant association between SITs and drug resistance

Physio-ultrastructural footprints and iTRAQ-based proteomic approach unravel the role of Piriformospora indica-colonization in counteracting cadmium toxicity in rice

Due to its immense capability to concentrate in rice grain and ultimately in food chain, cadmium (Cd) has become the cause of an elevated concern among agriculturists, scientists and the environmental activists. Symbiotic association of Piriformospora indica (P. indica) has been characterized as a potential aid in combating heavy metal stress in plants for sustainable crop production but our scant knowledge regarding ameliorative tendency of P. indica against Cd, specifically in rice, necessitates an in-depth investigation. This study aimed at elaborating the underlying mechanisms involved in P. indica-mediated tolerance against Cd stress in two rice genotypes, IR8 and ZX1H, varying in Cd accumulation pattern. Either colonized or un-inoculated with P. indica, seedlings of both genotypes were subjected to Cd stress. The results showed that P. indica colonization significantly supported plant biomass, photosynthetic attributes and chlorophyll contents in Cd stressed plants. P. indica colonization sustained chloroplast integrity and reduced Cd translocation (46% and 64%), significantly lowering malondialdehyde (MDA) content (11.3% and 50.4%) compared to uninoculated roots under Cd stress in IR8 and ZX1H, respectively. A genotypic difference was evident when a 2-fold enhancement in root peroxidase (POD) activity was recorded in P. indica colonized IR8 plants as compared to ZX1H. The root proteomic analysis was performed using isobaric tags for relative and absolute quantification (iTRAQ) and the results showed that P. indica alleviates Cd stress in rice via down-regulation of key glycolysis cycle enzymes in a bid to reduce energy consumption by the plants and possibly re-directing it to Cd defense response pathways; and up-regulation of glutamine synthetase, a key enzyme in the L-Arg-dependent pathway for nitric oxide (NO) production, which acts as a stress signaling molecule, thus conferring tolerance by reduction of NO-mediated modification of essential proteins in response to Cd stress. Conclusively, both the tested genotypes benefited from P. indica symbiosis at varying levels by an enhanced detoxification capacity and signaling efficiency in response to stress. Hence, a step forward towards the employment of an environmentally sound and self-renewing approach holding the hope for a healthy future