Journal of Pathogens最新文献

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.

Uropathogenic Escherichia coli (UPEC) adhere to cells in the human urinary tract via type 1 pili that undergo phase variation where a 314-bp fimS DNA element flips between Phase-ON and Phase-OFF orientations through two site-specific recombinases, FimB and FimE. Three fim-lux operon transcriptional fusions were created and moved into the clinical UPEC isolate NU149 to determine their temporal regulation in UPEC growing in the urinary tract. Within murine urinary tracts, the UPEC strains demonstrated elevated transcription of fimA and fimB early in the infection, but lower transcription by the fifth day in murine kidneys. In contrast, fimE transcription was much lower than either fimA or fimB early, increased markedly at 24 h after inoculation, and then dropped five days after inoculation. Positioning of fimS was primarily in the Phase-ON position over the time span in UPEC infected bladders, whereas in UPEC infected murine kidneys the Phase-OFF orientation was favored by the fifth day after inoculation. Hemagglutination titers with guinea pig erythrocytes remained constant in UPEC growing in infected murine bladders but fell substantially in UPEC infected kidneys over time. Our results show temporal in vivo regulation of fim gene expression in different environmental niches when UPEC infects the murine urinary tract.

Pyogenic wound infections are one of the most common clinical entities caused and aggravated by the invasion of pathogenic organisms. Prompt and aggressive antimicrobial therapy is needed to reduce the burden and complications associated with these infections. In this study, we intended to investigate the common pathogens and their antimicrobial susceptibility patterns from the pyogenic wound infections at a tertiary care hospital in Kathmandu, Nepal. A laboratory based cross-sectional study was carried out among the pyogenic clinical specimens of the patients visiting Manmohan Memorial Teaching Hospital, Kathmandu, Nepal. Processing of clinical specimens and isolation and identification of bacterial pathogens were carried out using standard microbiological methods. Antimicrobial susceptibilities and resistant profiles were determined by following the standard guidelines of Clinical and Laboratory Standards Institute (CLSI). About 65% of the clinical specimens were positive for the bacterial growth and Gram positive bacteria (57.4%) were the leading pathogens among pyogenic wound infections. Staphylococcus aureus (412, 49.28%), Escherichia coli (136, 16.27%), Klebsiella spp. (88, 10.53%), and Pseudomonas spp. (44, 5.26%) were the common pathogens isolated. High level of drug resistance was observed among both Gram positive bacteria (51.9%) and Gram negative bacteria (48.7%). Gram positive isolates were resistant to ampicillin, ciprofloxacin, cotrimoxazole, erythromycin, and cloxacillin. Gram negative isolates were resistant to cephalosporins but were well susceptible to amikacin and imipenem. Pyogenic wound infections are common in our hospital and majority of them were associated with multidrug resistant bacteria. The detailed workup of the prevalent pathogens present in infected wounds and their resistance pattern is clearly pertinent to choosing the adequate treatment.

Our study aimed to describe the epidemiological, clinical, and diagnostic aspects of African histoplasmosis in Togo through a descriptive and cross-sectional study on histological diagnosed African histoplasmosis in Pathology Department of Lomé from 2002 to 2016 (15 years). A total of 17 cases of African histoplasmosis were diagnosed. The sex ratio (M/F) was 1.8. The annual incidence was 1.1 cases. The mean age of the patients was 27.2 ± 0.4 years. All our patients were of social categories with a low socioeconomic level. HIV infection was known in 3 patients and one patient contracted tuberculosis. The clinical manifestations were cutaneous in 7 cases, cutaneous and mucous in 3 cases, cutaneous and lymph node in 3 cases, cutaneous and bone in 2 cases, and disseminated in 2 cases. The samples examined consisted of 14 cutaneous biopsies measuring 2-3 cm and 3 ganglionic biopsies each measuring 4 cm of major axis. Histologically, all cases were of chronic form made of granulomatous reaction with ovoid yeasts measuring between 1 and 2 microns. Despite the low frequency of this disease in our country, it should be kept constantly in mind before any granulomatous lesions, especially in the context of the HIV pandemic.

Epstein-Barr virus (EBV) is a pathogen that infects more than 90% of global human population. EBV primarily targets B-lymphocytes and epithelial cells while some of them infect monocyte/macrophage, T-lymphocytes, and dendritic cells (DCs). EBV infection does not cause death by itself but the infection has been persistently associated with certain type of cancers such as nasopharyngeal carcinoma (NPC), Burkitt's lymphoma (BL), and Hodgkin's lymphoma (HL). Recent findings have shown promise on targeting EBV proteins for cancer therapy by immunotherapeutic approach. Some studies have also shown the success of adopting EBV-based therapeutic vaccines for the prevention of EBV-associated cancer particularly on NPC. In-depth investigations are in progress to refine the current therapeutic and vaccination strategies. In present review, we discuss the highly potential EBV targets for NPC immunotherapy and therapeutic vaccine development as well as addressing the underlying challenges in the process of bringing the therapy and vaccination from the bench to bedside.

Hepatitis E virus (HEV) remains a major public health concern in resource limited regions of the world. Yet data reporting is suboptimal and surveillance system is inadequate. In Nigeria, there is dearth of information on prevalence of acute HEV infection. This study was therefore designed to describe acute HEV infection among antenatal clinic attendees and community dwellers from two geographical regions in Nigeria. Seven hundred and fifty plasma samples were tested for HEV IgM by Enzyme Linked Immunosorbent Assay (ELISA) technique. The tested samples were randomly selected from a pool of 1,115 blood specimens previously collected for viral hepatitis studies among selected populations (pregnant women, 272; Oyo community dwellers, 438; Anambra community dwellers, 405) between September 2012 and August 2013. One (0.4%) pregnant woman in her 3rd trimester had detectable HEV IgM, while community dwellers from the two study locations had zero prevalence rates of HEV IgM. Detection of HEV IgM in a pregnant woman, especially in her 3rd trimester, is of clinical and epidemiological significance. The need therefore exists for establishment of a robust HEV surveillance system in Nigeria and especially amidst the pregnant population in a bid to improve maternal and child health.

Fulminant hepatitis (FH) is a life-threatening liver disease characterised by intense immune attack and massive liver cell death. The common precore stop codon mutation of hepatitis B virus (HBV), A1896, is frequently associated with FH, but lacks specificity. This study attempts to uncover all possible viral nucleotides that are specifically associated with FH through a compiled sequence analysis of FH and non-FH cases from acute infection. We retrieved 67 FH and 280 acute non-FH cases of hepatitis B from GenBank and applied support vector machine (SVM) model to seek candidate nucleotides highly predictive of FH. Six best candidates with top predictive accuracy, 92.5%, were used to build a SVM model; they are C2129 (85.3%), T720 (83.0%), Y2131 (82.4%), T2013 (82.1%), K2048 (82.1%), and A2512 (82.1%). This model gave a high specificity (99.3%), positive predictive value (95.6%), and negative predictive value (92.1%), but only moderate sensitivity (64.2%). We successfully built a SVM model comprising six variants that are highly predictive and specific for FH: four in the core region and one each in the polymerase and the surface regions. These variants indicate that intracellular virion/core retention could play an important role in the progression to FH.

Response of Nigerian indigenous (local) and broiler chickens to experimental Eimeria infections was investigated by measures of clinical signs, packed cell volume (PCV), body weights (BW), feed consumption, faecal oocyst counts (oocyst per gram), and microscopic intestinal lesions. Three-week-old chickens of each breed received single pulse infections with 2500, 5000, and 100.000 sporulated Eimeria oocysts. Infected birds were dull and passed bloody diarrhoea. OPG showed a dose related response but no significant difference between groups (P > 0.05). OPG was significantly higher in local chickens (P < 0.05) and varied significantly with time (P < 0.05). PCV declined significantly in infected birds within breeds and groups (P < 0.05); however, the decline in PCV was significantly greater in broilers (P < 0.05). Both breeds had significant BW gains (P < 0.05). BW gain varied between groups being significantly higher in the uninfected control broilers than in the infected broilers (P < 0.05). Comparatively, broilers gained significantly more BW than their local counterparts (P < 0.05). Feed intake increased significantly with time (P < 0.05) in both breeds. The Eimeria isolate was pathogenic to both breeds of chicken although clinical signs and lesions were more severe in indigenous chickens suggesting the breed's more susceptibility.

The Xpert MTB/RIF assay can detect mutations in rpoB gene that confer rifampicin resistance (RR) using five overlapping probes (A, B, C, D, and E). In this study, we described our experience with the Xpert assay in a rural setting in India. During the study period, 3250 samples were processed. The result was unsuccessful in 5.7% of cases. For extrapulmonary specimens, the risk of unsuccessful result was higher in tissue biopsy and stool samples. Among samples positive for Mycobacterium tuberculosis, rifampicin resistance was indeterminate in 1.2% of them. Our results and a review of the literature showed that the most frequent mutations conferring RR were located in the region of Probe E (63.6%; 95% confidence interval [CI] 56.26-70.94), followed by Probe B (15.02%; 95% CI 11.94-18.10), Probe D (13.35%; 95% CI 10.01-16.69), Probe A (4.73%; 95% CI 1.92-7.54), and Probe C (1.61%; 95% CI 0.67-2.54). Although the high cost of the cartridges precluded using the Xpert assay for routine diagnosis of tuberculosis, our results demonstrate that the assay can be used to diagnose RR-tuberculosis in rural areas with limited laboratory infrastructure and could be a convenient tool to investigate the molecular epidemiology of RR in resource-limited settings.