The present study aimed to assess the population structure of Mycobacterium tuberculosis (MTB) isolates from Egypt. A total of 230 MTB isolates were analysed using spoligotyping, large sequence polymorphism (LSPs), mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) typing and multi-locus sequence typing (MLST). The majority of isolates (93.0%) belonged to lineage 4, including 44.3, 13.4 and 10.8% of the ill-defined T clade, LAM and Haarlem families, respectively, and lineage 3 was identified in 7.0% of the isolates. MIRU-VNTRs typing allowed efficient discrimination of the spoligotype-defined clusters, including spoligo-international types (SIT) 53, 34, and 4, into 56 patterns, including 13 clusters and 43 unique patterns. A new SNP at position 311614 was identified in all six isolates to form the biggest MIRU-VNTR cluster, which suggested a recent clonal expansion. This SNP could possibly be used as a genetic marker for robust discriminations of Egyptian MTB isolates belonging to SIT53. The combination of spoligotyping, 12 MIRU-VNTRs loci and MLST provided insight into the genetic diversity and transmission dynamics of the Egyptian MTB genotypes and could be a key to implementation of effective control measures by public health authorities.

Abstract: The bactericidal efficiency of AgNP was evaluated against Total bacterial Counts (TBC), Total Coliform Counts (TCC) and Total Faecal Streptococcal Counts (TFS) of water samples collected from fish farms water. Our finding showed that the highest concentration of Ag nanoparticle exhibited highest bactericidal efficiency against TBC where after 2 hours contact time, 0.1, 0.05 and 0.01 mg/L Ag nanoparticle was sufficient to inhibit (85.33 %, 71.93 % and 62.19 %) of TBC in fish farms water. Moreover, the results showed that the lowest mean of TCC was at 0.1 ppm of AgNP after 2 hrs. contact time (144.21 ± 99.94), where its antibacterial activity reached to 92.48 % and this percentage of TCC inhibition was higher than the other 2 concentrations at the same times (58.34 % for 0.05 ppm and 31.01 % for 0.01 ppm at 2 hrs.). Furthermore, the results showed that the lowest mean of TFS was the mean of 0.1 ppm of AgNP after 2 hrs. contact time (155.50 ± 60.86) followed by 0.1 ppm after 1 hr. contact time (212.46 ± 97.46). Moreover, the highest concentration (0.1 ppm) produced highest antibacterial activity against TFS and its efficiency reached to 90.48 % followed by 0.05 ppm, which resulted in 87.82 % inhibition of TFS after 2hrs.The mean value of 0.1 ppm at 1hr. nearly equal in their inhibition to 0.05 at 2hrs., while the inhibition of 0.1 at 5 min. was higher than 0.01 at 2 hrs. contact time. Also, our results revealed that there were significant positive correlations between water pH, water hardness, chemical oxygen demand (COD) and TBC, TCC, TFS count, this means that when water pH, water hardness, COD increased there were increase in the bacterial count (decreased AgNP efficiency), while there were significant negative correlations between water temperature and TBC, TCC, TFS, this means that when the water temperature increased there was decrease in the bacterial count (increased AgNP efficiency) and vice versa. Silver nanoparticles proved good efficiency against Faecal bacterial indicators and TBC of water, so we recommend using the silver nanoparticles in the field of fish farms water treatment. To obtain a good efficiency of silver nanoparticles, the fish farms water must be treated to remove water hardness and organic matter before the applications of AgNP.

The bactericidal efficiency of AgNP was evaluated against Total Bacterial Count (TBC), Total Coliform count(TCC) and Total fecal streptococcal Count (TFS) of water samples collected from surface water and ground water. Silver nanoparticles were synthesized in a typical one-step synthesis protocol through chemical reduction of silver nitrate by soluble starch. Silver nanoparticles were characterized using Transmission Electron Microscopy (size) and Atomic absorption spectrophotometer (concentration), the bactericidal efficiency of AgNP was evaluated by application of it in three concentrations 0.1, 0.05 and 0.01 ppm to each water sample, each concentration allowed to interact with bacterial communities of the water for several contact times, namely 5 min. 15 min., 30 min., 1 hr. and 2 hrs., then the bactericidal efficiency of AgNPs was determined by comparing the counting bacteria before and after treatment for each sample. We found that, the higher mean values of TBC, TCC and TFS were detected in surface water than ground water. Also,our obtained results showed that TBC, TCC and TFS exceeding permissible limits. Moreover, the statistical analysis of data showed that application of AgNp at different concentration, the Total bacterial count was significantly reduced in all AgNP-exposed samples when compared with the control group (P0.05). Also, our results showed that the highest bacterial inhibition was at the highest concentration of AgNP (0.1 ppm) at maximum time used (2hrs.). Our results showed that the highest concentration of Ag nano particle exhibited highest bactericidal efficiency against TBC, where after 2hrs.contact time, 0.1, 0.05 and 0.01 mg/L Ag nano particle was sufficient to inhibit (91.85 %, 89.14 % and 74.92 %) and (92.33 % , 85.23 % and 53.17 %) of TBC in surface water and ground water, respectively. Moreover, the inhibition efficiency of the highest concentration (0.1 ppm) against TCC reached to 98.10% and 99.88% in surface water and 95.54 % and 99.20 % in ground water after 1hr. and 2hrs. contact times, respectively. Nearly, the same result was detected against Fecal streptococcal count.