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This study aimed to evaluate the accuracy of detecting drug-resistant Mycobacterium tuberculosis complex (MTBC)-specific DNA in sputum specimens from 48 patients diagnosed with pulmonary tuberculosis. The presence of MTBC DNA in the specimens was validated using the GeneXpert MTB/RIF system and compared with a specific PCR assay targeting the IS6110 and the mtp40 gene sequence fragments. Additionally, the results obtained by multiplex PCR assays to detect the most frequently encountered rifampin, isoniazid, and ethambutol resistance-conferring mutations were matched with those obtained by GeneXpert and phenotypic culture-based drug susceptibility tests. Of the 48 sputum samples, 25 were positive for MTBC using the GeneXpert MTB/RIF test. Nevertheless, the IS6110 and mtp40 single-step PCR revealed the IS6110 in 27 of the 48 sputum samples, while the mtp40 gene fragment was found in only 17 of them. Furthermore, multiplex PCR assays detected drug-resistant conferring mutations in 21 (77.8%) of the 27 samples with confirmed MTBC DNA, 10 of which contained single drug-resistant conferring mutations towards ethambutol and two towards rifampin, and the remaining nine contained double-resistant mutations for ethambutol and rifampin. In contrast, only five sputum specimens (18.5%) contained drug-resistant MTBC isolates, and two contained mono-drug-resistant MTBC species toward ethambutol and rifampin, respectively, and the remaining three were designated as multi-drug resistant toward both drugs using GeneXpert and phenotypic culture-based drug susceptibility tests. Such discrepancies in the results emphasize the need to develop novel molecular tests that associate with phenotypic non-DNA-based assays to improve the detection of drug-resistant isolates in clinical specimens in future studies.

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Soil replacement is an effective technique used in construction practices. Hence, several studies have considered the mechanisms to remove and replace mitigation in the past. This research represents an analysis of the efficiency of cemented stabilized soil replacement for improving the behaviour of weak soil. On the other hand, the optimum design for foundation depends on the soil properties beneath these foundations. One of the best solutions for this challenge is to increase the shear parameters and reduce the compressibility for the foundation soil using cemented sand mixture technique. An experimental program was conducted to study the impact of cement stabilization on the geotechnical characteristics of sandy soils, furthermore, five cement ratios (3%, 5%, 7%, 10% and 15% by dry weight of sand) have been mixed with sandy soil and tested under compaction and shearing. The results illustrated that the maximum dry unit weight of sand increases with the increase in cement content whereas the optimum moisture content decreases marginally with the increase in the cement content. In addition, increasing cement content leads to an increase of cohesion, friction angle and Young's modulus. This paper is considered a serious attempt to estimate the optimum cement ratio required to improve the mechanical properties of soil replacement under a strip footing. Numerical modelling for this footing was done by Plaxis software. The results illustrated that adding the cement mixture improves the behaviour of footing. The effect of the replacement extension on the strip footing is also analyzed, where; the results indicated that the optimum replacement extension is equal to the thickness of replacement. This study is based on the limitation of the herein proposed numerical model and its properties. [ABSTRACT FROM AUTHOR]

This study was conducted to determine what effects nanoparticles (NPs) like TiO2, ZnO, and Ag may pose on natural attenuation processes of petroleum hydrocarbons in contaminated soils. The solid NPs used were identified using x‐ray diffraction technique and their average size was certified as 18.2, 16.9, and 18.3 nm for Ag‐NPs, ZnO‐NPs, and TiO2‐NPs, respectively. NPs in soil microcosms behave differently where it was dissolved as in case of Ag‐NPs, partially dissolved as in ZnO‐NPs or changed into other crystalline phase as in TiO2‐NPs. In this investigation, catabolic gene encoding catechol 2,3 dioxygenase (C23DO) was selected specifically as biomarker for monitoring hydrocarbon biodegradation potential by measuring its transcripts by RT‐qPCR. TiO2‐NPs amended microcosms showed almost no change in C23DO expression profile or bacterial community which were dominated by Bacillus sp., Mycobacterium sp., Microbacterium sp., Clostridium sp., beside uncultured bacteria, including uncultured proteobacteria, Thauera sp. and Clostridia. XRD pattern suggested that TiO2‐NPs in microcosms were changed into other non‐inhibitory crystalline phase, consequently, showing the maximum degradation profile for most low molecular weight oil fractions and partially for the high molecular weight ones. Increasing ZnO‐NPs concentration in microcosms resulted in a reduction in the expression of C23DO with a concomitant slight deteriorative effect on bacterial populations ending up with elimination of Clostridium sp., Thauera sp., and uncultured proteobacteria. The oil‐degradation efficiency was reduced compared to TiO2‐NPs amended microcosms. In microcosms, Ag‐NPs were not detected in the crystalline form but were available in the ionic form that inhibited most bacterial populations and resulted in a limited degradation profile of oil, specifically the low molecular weight fractions. Ag‐NPs amended microcosms showed a significant reduction (80%) in C23DO gene expression and a detrimental effect on bacterial populations including key players like Mycobacterium sp., Microbacterium sp., and Thauera sp. involved in the biodegradation of petroleum hydrocarbons. [ABSTRACT FROM AUTHOR]

Eight isolates identified as belonging to the genus Bacillus were obtained from Aloqt (a crusty dried product made from goat milk). The cell-free culture supernatant (CFCS) from the eight isolates possessed an inhibitory spectrum against Staphylococcus aureus and Escherichia coli . The eight unknown bacterial isolates were identified by PCR amplification of their 16S ribosomal RNA gene and sequencing of the resulting PCR products. All of the isolates were classified as members of Bacillus amyloliquefaciens , as their 16S rDNA similarities to the respective species were greater than 99%. The phylogenetic analysis grouped two isolates with strain BCRC 11601 and the remaining six isolates with strains MPA 1034 and BCRC 11601. The inhibitory activity of the CFCS was either highly reduced or fully inactivated when treated by proteolytic enzymes, suggesting the possible involvement of a protein/polypeptide bacteriocin-like inhibitory substance (BLIS) in their antagonism. The optimum growth conditions for maximum inhibitory activity were achieved at an initial pH of 7, incubation temperature of 37 °C, and NaCl concentration of (1%). A considerable decrease and/or complete loss of activity occurred at values above and below the optimum. The maximum inhibitory activity occurred after 24 h of incubation; as the incubation time increased, a decrease in the activity was observed until a complete loss of activity occurred after 72 h of incubation. [ABSTRACT FROM AUTHOR]