Journal of Pathogens最新文献

A quantitative structure-activity relationship (QSAR) study was performed to develop a model that relates the structures of 50 compounds to their activities against M. tuberculosis. The compounds were optimized by employing density functional theory (DFT) with B3LYP/6-31G^⁎. The Genetic Function Algorithm (GFA) was used to select the descriptors and to generate the correlation model that relates the structural features of the compounds to their biological activities. The optimum model has squared correlation coefficient (R²) of 0.9202, adjusted squared correlation coefficient (R_adj) of 0.91012, and leave-one-out (LOO) cross-validation coefficient (Q_cv²) value of 0.8954. The external validation test used for confirming the predictive power of the built model has R²pred value of 0.8842. These parameters confirm the stability and robustness of the model. Docking analysis showed the best compound with high docking affinity of -14.6 kcal/mol which formed hydrophobic interaction and hydrogen bond with amino acid residues of M. tuberculosis cytochromes (Mtb CYP121). QSAR and molecular docking studies provide valuable approach for pharmaceutical and medicinal chemists to design and synthesize new anti-Mycobacterium tuberculosis compounds.

Poultry meat is one of the most important sources of infection of Yersinia spp. for humans. The aim of the present study was to evaluate the incidence of Yersinia enterocolitica in chicken meat by using culture method on selective medium and confirmation by PCR assay. Also, biochemical methods were used for biotyping. A total of 100 chicken thigh meat samples were collected randomly from retail outlets in Mashhad, Iran. Samples were enriched in Peptone-Sorbitol-Bile (PSB) broth and then cultured on Cefsulodin-Irgasan-Novobiocin (CIN) agar containing antibiotics supplement. The DNA was extracted from suspected colonies of Yersinia spp. and then PCR test using specific primers for 16S rRNA gene of Yersinia enterocolitica was performed. In this study, 30% of chicken meat was contaminated with Yersinia spp. by culture method and 25% of chicken meat was contaminated with Yersinia enterocolitica. Biotyping of isolated colonies showed that all of the isolates belonged to biotype 1A. Culture and detection of Yersinia spp. from food samples traditionally take 4 days. Due to high accuracy and speed of PCR assay, it is a good alternative method for microbiological techniques. In conclusion, poultry meat can act as a source of Y. enterocolitica and could be considered as a public health hazard.

Background: Multidrug-resistant tuberculosis (MDR-TB) has continued to be a challenge for tuberculosis (TB) control globally. Ethiopia is one of the countries with high MDR-TB burden.

Objective: The main purpose of this study was to determine the prevalence of MDR-TB and associated factors in Ethiopia.

Methods: A systematic review of the literatures on prevalence of MDR-TB and associated factors was conducted in the country.

Results: In our electronic search, 546 citations were depicted. Among the total 546 citations described, a total of 22 articles met eligibility criteria and were included in the review article. According to our review, the prevalence of MDR-TB ranged from 0 to 46.3%. The average mean rate of MDR-TB in Ethiopia was found to be 12.6 ± 15.9%. The overall prevalence of MDR-TB in all TB cases was estimated to be 1.4%. From a total of 3849 patients studied, 527 had MDR-TB. Previous exposure to antituberculosis treatment was the most commonly identified risk factor of MDR-TB in Ethiopia.

Conclusion: Despite relative decline in incidence of MDR-TB, the distribution and prevalence of MDR-TB continued to be a serious challenge for TB control in Ethiopia. Previous exposure to antituberculosis treatment was also the most common risk factor for MDR-TB. Therefore, strong TB and MDR-TB treatment along with tight introduction of follow-up strategies should be applied for better TB control.

Carbapenem-resistant Enterobacteriaceae (CRE) organisms have emerged to become a major global public health threat among antimicrobial resistant bacterial human pathogens. Little is known about how CREs emerge. One characteristic phenotype of CREs is heteroresistance, which is clinically associated with treatment failure in patients given a carbapenem. Through in vitro whole-transcriptome analysis we tracked gene expression over time in two different strains (BR7, BR21) of heteroresistant KPC-producing Klebsiella pneumoniae, first exposed to a bactericidal concentration of imipenem followed by growth in drug-free medium. In both strains, the immediate response was dominated by a shift in expression of genes involved in glycolysis toward those involved in catabolic pathways. This response was followed by global dampening of transcriptional changes involving protein translation, folding and transport, and decreased expression of genes encoding critical junctures of lipopolysaccharide biosynthesis. The emerged high-level carbapenem-resistant BR21 subpopulation had a prophage (IS1) disrupting ompK36 associated with irreversible OmpK36 porin loss. On the other hand, OmpK36 loss in BR7 was reversible. The acquisition of high-level carbapenem resistance by the two heteroresistant strains was associated with distinct and shared stepwise transcriptional programs. Carbapenem heteroresistance may emerge from the most adaptive subpopulation among a population of cells undergoing a complex set of stress-adaptive responses.

Significance of methylene blue (MB) in photodynamic therapy against microbes is well established. Previously, we have reported the antifungal potential of MB against Candida albicans. The present study attempts to identify additional antimicrobial effect of MB against another prevalent human pathogen, Mycobacterium tuberculosis (MTB). We explored that MB is efficiently inhibiting the growth of Mycobacterium at 15.62 μg/ml albeit in bacteriostatic manner similar to its fungistatic nature. We uncovered additional cell surface phenotypes (colony morphology and cell sedimentation rate) which were impaired only in Mycobacterium. Mechanistic insights revealed that MB causes energy dependent membrane perturbation in both C. albicans and Mycobacterium. We also confirmed that MB leads to enhanced reactive oxygen species generation in both organisms that could be reversed upon antioxidant supplementation; however, DNA damage could only be observed in Mycobacterium. We provided evidence that although biofilm formation was disrupted in both organisms, cell adherence to human epithelial cells was inhibited only in Mycobacterium. Lastly, RT-PCR results showed good correlation with the biochemical assay. Together, apart from the well-established role of MB in photodynamic therapy, this study provides insights into the distinct antimicrobial mode of actions in two significant human pathogens, Candida and Mycobacterium, which can be extrapolated to improve our understanding of finding novel therapeutic options.

Background: The CTX-M family of extended-spectrum beta lactamase (ESBL) enzymes is comprised of over 60 bla_CTX-M gene variants with the predominance of bla_CTX-M-15 in many regions. In this report, we present the first description of bla_CTX-M-28 in the United Arab Emirates.

Methods: Forty-five non-duplicate ESBL producing isolates identified in a secondary care facility in the United Arab Emirates from June to July 2016 were studied. Gene sequencing was performed and DNA sequences were annotated using the BLAST program to identify the gene subtypes.

Results: The majority of the ESBL positive isolates were E. coli (n/N = 39/45; 86.6%) followed by K. pneumoniae (n = 5) and K. oxytoca (n = 1). All isolates harboured bla_CTX-M and bla_TEM genes, 18 had bla_SHV, and 2 were bla_VIM positive. Thirty-seven isolates (82.2%) were positive for bla_CTX-M-28. Other bla_CTX-M genes identified include bla_CTX-M-167 (n = 2; isolates #1 and 26) and one each for bla_CTX-M-38, bla_CTX-M-163, and bla_CTX-M-198. No bla_CTX-M-15 was identified. The predominant bla_TEM subtype was bla_TEM-171 (n = 8) followed by one of each of bla_TEM-120, bla_TEM-163, and bla_TEM-206. The bla_SHV subtypes were bla_SHV-148 and bla_SHV-187.

Conclusion: The findings indicate the first description of bla_CTX-M-28 in a setting where bla_CTX-M-15 was previously predominant.

Brucellosis is endemic in Bangladesh both in humans and in animals. A number of reasons complicate the diagnosis, as bovine brucellosis can be diagnosed by various serological tests. But the tests have a limitation; when the organism remains intracellular, the disease goes into chronic stage and the antibody titres may decline. The present study was conducted for isolation and detection of Brucella spp. by polymerase chain reaction (PCR) from seronegative cows. A total of 360 dairy cows from three geographical regions were screened serologically by Rose Bengal Plate Test (RBPT) where 24 samples were serologically positive and the rest of the samples were serologically negative. Among the 24 seropositive individuals, 11 were culture positive and 6 were culture positive from serologically negative dairy cows. The overall seroprevalence of brucellosis in cattle was 6.6% and in disease condition a higher prevalence was recorded in abortion (28.07%) followed by infertility (13.33%). To confirm the Brucella spp. in seronegative dairy cattle, the isolates were extracted and PCR was conducted, which produced 905 bp amplicon size of 6 Brucella spp. from milk sample. So, for the detection or eradication of brucellosis, a bacteriological test and a PCR technique should be performed with the serological test of milk.

This study was conducted to assess highly pathogenic Beauveria bassiana isolates to be used in biocontrol and to determine their potentials as mycopesticide. For this purpose, two B. bassiana isolates, which were locally isolated from T. urticae, were chosen. Firstly, three suspensions were investigated at the degree of humidity of 65 ± 5% and 100% RH. Secondly, these strains were selected according to their tendency to mass production, tolerance to UV radiation, and capability of producing spore at the different temperatures. Finally, identification of the selected isolate was performed by using ITS rDNA analysis. Both tested fungal isolates were pathogenic to the T. urticae. Mycelial growths of isolate AT076 at 20°C and 30°C were found to be greater than isolate AT007. It was observed that isolate AT076 had more spore production with 1.61 × 10⁷ spore/disc at 30°C and 44.33% germination after UV radiation for 15 min. The numbers of spores per 5 mm disk area for isolates AT076 and AT007 were found to be 1.2 × 10⁶ and 1.0 × 10⁶. These results show that isolate AT076 was more virulent and more UV-tolerant and had higher tendency to mass production compared to isolate AT007 against T. urticae. As a result of this study, isolate AT076 can be used in the biocontrol as mycopesticide.