Journal of Pathogens最新文献

Rotavirus has been identified as a major cause of gastroenteritis in Nigeria. There is limited information on the intragenotype diversity of Nigerian rotavirus isolates. We therefore investigated the molecular characteristics of some rotavirus gene sequences detected in sewage from Nigeria. Seven sewage samples, out of a total of 68, tested positive for rotavirus RNA (10.3%). Genotype G1P[4] was the most common genotype (5 isolates) and one isolate for genotypes G1P[8] and G3P[6]. Phylogenetic analysis of the partial VP7 gene of 3 G1P[4] isolates analyzed identified them as genotype G1 Lineage 2 along with Chinese strains with 99.1% to 100% amino acid similarity. Amino acid substitutions D-97→E and S-147→D/N were observed within the 7-1a and 7-2 domains of VP7 gene among the study G1P4 isolates in reference to vaccine strain RotaTeq®. Phylogenetic analysis of the G3P[6] study isolate identified it as genotype G3 Lineage 3, forming a monophyletic cluster with 100% bootstrap value with other West African strains G3 isolates. Phylogenetic analysis of GIP[4] VP4 genes identified them as P4 Lineage 5, while 3 NSP4 gene sequences belonged to genotype E1, while 1 belonged to E2. The results from this study represent phylogenetic analysis of partial gene sequences of environmental group A rotavirus (RVA) isolates from Nigeria.

Objectives: Nontuberculous mycobacteria (NTM) incidences are on the rise worldwide, including the tuberculosis endemic areas. They should be identified rapidly to the species level and should be carefully differentiated as contamination, colonization, or disease. This study was aimed at determining the prevalence and clinicoepidemiological profile of mycobacteriosis cases.

Materials and methods: Cultures were made on liquid and solid media. NTM were identified by polymerase chain reaction (PCR) restriction analysis (PRA) and gene sequencing. Data was analyzed using Epi-info 7.

Results: Out of the 1042 processed specimens, 16% were positive for M. tuberculosis complex and 1.2% for clinically significant NTM. M. intracellulare was the commonest species isolated. NTM were treated mainly on outdoor basis (92%), involving more extrapulmonary system (62%) and higher age-group of 41-60 years (69%). No significant factor was seen to be associated clinically, radiologically, and biochemically with the NTM infections.

Conclusions: Our study highlights the importance of early diagnosis and differentiation among Mycobacterium tuberculosis and NTM so that these NTM are not underestimated in routine diagnostic procedures merely as environmental or laboratory contaminants.

Many of the earlier studies involving the effect of isoniazid (INH) treatment have solely focused on the fatty acyl (FA) category of Mycobacterium tuberculosis (MTB) lipids. This motivated us with the major interest to examine the impact of INH on various other categories of MTB lipids. Towards this, we chose to interpret our mass spectral data (LC-ESI-MS) by a standalone software, MS-LAMP, in which "Mtb LipidDB" was integrated. Analysis by MS-LAMP revealed that INH treatment can alter the composition of "glycerolipids (GLs)" and "glycerophospholipids (GPLs)" categories of MTB lipids, in addition to the variations to FA category. Interpretation by "MycoMass" database yielded similar results as that of Mtb LipidDB, except that significant alterations to polyketides (PKs) category also were observed. Probing biosynthetic pathways of certain key lipids belonging to any of GLs, GPLs, and PKs categories can be attractive target(s) for drug discovery or can be useful to identify means to overcome drug resistance or to obtain insights into the causal factors of virulence. To the best of our knowledge, this is the first report hinting at the influence of INH on GLs, GPLs, and PKs of MTB.

There is an increasing need for innovative drug and prophylaxis discovery against malaria. The aim of the present study was to test in vivo antiplasmodial activity of Croton macrostachyus H. (Euphorbiaceae) stem bark extracts from Kenyan folkloric medicine. Inbred Balb/c mice were inoculated with erythrocytes parasitized with Plasmodium berghei (ANKA). Different doses (500, 250, and 100 mg/kg) of C. macrostachyus ethyl acetate, methanol, aqueous, and isobutanol extracts were administrated either after inoculation (Peters' 4-day suppressive test) or before inoculation (chemoprotective test) of the parasitized erythrocytes. All the extracts showed significant suppression of parasitemia compared to control (p < 0.001): for the ethyl acetate extract in the range of 58-82%, for the methanol extract in the range of 27-68%, for the aqueous extract in the range of 24-72%, and for the isobutanol extract in the range of 61-80%. Chemoprotective effect was significant (p < 0.001) and the suppression caused by the ethyl acetate extract was between 74 and 100%, by the methanol extract between 57 and 83%, and by the isobutanol extract between 86-92%. The study showed that it is possible to inhibit the growth of the parasites by various stem bark extracts of C. macrostachyus in Balb/c mice supporting the folkloric use of the plant against malaria.

Acquired immunodeficiency syndrome (AIDS) cases are on the rise globally. To date, there is still no effective measure to eradicate the causative agent, human immunodeficiency virus (HIV). Highly active antiretroviral therapy (HAART) is being used in HIV/AIDS management, but it results in long-term medication and has major drawbacks such as multiple side effects, high cost, and increasing the generation rate of escape mutants. In addition, HAART does not control HIV-related complications, and hence more medications and further management are required. With this, other alternatives are urgently needed. In the past, small-molecule inhibitors have shown potent antiviral effects, and some of them are now being evaluated in clinical trials. The challenges in developing these small molecules for clinical use include the off-target effect, poor stability, and low bioavailability. On the other hand, antibody-mediated therapy has emerged as an important therapeutic modality for anti-HIV therapeutics development. Many antiviral antibodies, namely, broad neutralizing antibodies (bnAbs) against multiple strains of HIV, have shown promising effects in vitro and in animal studies; further studies are ongoing in clinical trials to evaluate their uses in clinical applications. This short review aims to discuss the current development of therapeutic antibodies against HIV and the challenges in adopting them for clinical use.

Helicobacter pylori (H. pylori) as gram-negative and spiral microorganism is responsible for colonization in the gastric microniche for more than 50% of world population. Recent studies have shown a critical role of H. pylori in the development of peptic ulcers, gastric mucosa-associated lymphoid tissue (MALT) lymphoma, and gastric cancer. Over the past decade, there has been a sharp interest to use noninvasive tests in diagnosis of the H. pylori infection. During the years after discovery by Marshall and Warren, it has been frequently declared that the rapid urease test (RUT) is one of the cheapest and rapid diagnostic approaches used in detecting the infection. Although the specificity and sensitivity are durable for this test, clinical experiences had shown that the ideal results are only achieved only if we take biopsies from both corpus and antrum at the same time. Given the diagnosis of the H. pylori in clinical samples, gastroenterologists are facing a long list of various molecular and nonmolecular tests. We need more in-depth researches and investigations to correctly generalize rapid and accurate molecular tests determining both bacterial identity and antibiotic resistance profile.

Regulation of the uropathogenic Escherichia coli (UPEC) fimB and fimE genes was examined following type 1 pili binding to mannose-coated Sepharose beads. Within 25 min after mannose attachment, fimE expression dropped eightfold, whereas fimB transcription increased about two- to fourfold. Because both fim genes encode site-specific recombinases that affect the position of the fimS element containing the fimA promoter, the positioning of fimS was also examined. The fimS element changed to slightly more Phase-OFF in bacteria mixed with plain beads, whereas UPEC cells interacting with mannose-coated beads had significantly less Phase-OFF orientation of fimS under pH 7 conditions. On the other hand, Phase-OFF oriented fimS increased fourfold when UPEC cells were mixed with plain beads in a pH 5.5 environment. Positioning of fimS was also affected by fimH mutations, demonstrating that the FimH ligand binding to its receptor facilitates the changes. Moreover, enzyme immunoassays showed that UPEC cells had greater type 1 pili expression when mixed with mannose-coated beads versus plain beads. These results indicate that, after type 1 pilus binding to tethered mannose receptors, the physiology of the E. coli cells changes to maintain the expression of type 1 pili even when awash in an acidic environment.

Escherichia coli O157:H7 is an enteric foodborne pathogen associated with life threatening disease conditions. The enterobacteria are frequently found in cattle gastrointestinal tract with high potential of contaminating animal products such as meat, milk, and cheese. A cross-sectional study was conducted to investigate the presence of Shiga toxin-producing Escherichia coli O157:H7 in milk products sold within Sokoto metropolis. Two hundred and sixty (260) samples (comprising 160 raw and 100 fermented milk samples) were collected from different sources within the study area. Bacteriological isolation and biochemical characterization yielded Escherichia coli with a detection rate of 9.23% (24/260). Molecular identification of the recovered isolates by PCR amplification of the Stx1 gene revealed Escherichia coli O157:H7 with a positive rate of 20.83% (5/24). The overall prevalence of E. coli O157:H7 was 1.92% (5/260) and the positive proportions for raw and fermented milk samples were 1.86% (3/160) and 2.0% (2/100), respectively. Fisher's Exact test showed a nonsignificant association between the isolates and the different milk types (p = 0.943; OR = 0.94; [95% CI: 0.154-5.704]). The results revealed presence of Escherichia coli O157:H7 in raw and fermented milk sold within Sokoto metropolis, Nigeria. The findings indicate possible feacal contamination of the milk products, with serious public health consequences. This necessitates the need to screen other milk products produced in the area such as butter and cheese. Health authorities in the State need to enlighten dairy farmers on the zoonotic potential of Escherichia coli O157:H7 and the role of cattle in the spread of the pathogen.

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.