JOURNAL OF MEDICAL MICROBIOLOGY AND INFECTIOUS DISEASES
Year:2018 | Volume:6 | Issue:1|Papers Count:7

Introduction: Vaccine studies against Pseudomonas aeruginosa have often focused on outer membrane proteins (OPRs) due to their potent stimulation of the immune response. Using major outer membrane proteins of cell walls (mOMPs) of P. aeruginosa and other Gram-negative bacteria actively stimulate the immune system without any toxic side effects. Moreover, these antigens show immunological cross-reactivity with mOMPs of other serotypes belonging to the same species. The main OPRs of P. aeruginosa, OprF, and OprL, have received much attention from biologists as the potential OPR-based vaccine candidates. Methods: Homology modeling of OprF and OprL was done based on the template structures obtained from the BLAST search. The quality of OprF and OprL molecules was assessed using GMQE and QMEAN4 quality assessment tools. The secondary structure of the proteins was predicted as well as the structural topology, subcellular localization, functional analyses, signal peptide and B cell epitopes of proteins. Results: The structures of OprF and OprL proteins were successfully modeled and assessed using 4RLC-A and 4G4V-A as template structures. The regions of the proteins with a high B cell epitope density were identified as candidates for vaccine design. These regions contain functional and exposed amino acids. In these regions, the majority of amino acids were hydrophilic, flexible and accessible. Conclusion: It should be noted that in silico approaches are appealing alternatives for empirical methods. These approaches could pave the way for precise vaccine design efforts with lower cost and time

Introduction: Giardia lamblia is a protozoan parasite with universal distribution in human populations. This infections transfer to human via contaminated foods and waters with Giardia cysts. The Knowledge on the incidence of this agent in the potential infection sources can provide valuable information for control and the spread of this parasite to human communities. This study was aimed to isolate and identify the Giardia lamblia cysts in the surface waters of Rasht city, Guilan province, north of Iran with microscopy and PCR assay. Methods: This cross-sectional study was performed on 45 samples of surface waters collected from rivers and wetlands in the vicinity of Rasht city. The samples were concentrated using nitrocellulose membrane filters, and the sediments were examined for Giardia cysts by microscopy with a magnification of 1000 X. Also, DNA was extracted from the sediments, and the heat shock protein gene of G. lamblia was amplified. Results: From 45 samples, 33. 33% and 40% were positive by microscopy and PCR, respectively. Conclusion: In comparison with the standard microscopic method, PCR showed more sensitivity for detection of G. lamblia cysts in water samples.

Introduction: The strain-specific capabilities of lactobacilli are critical for gut colonization. In this study, we evaluated various colonization determinants of 42 fecal Lactobacillus plantarum isolates from the healthy human fecal samples. Methods: We investigated the attachment to the Caco-2 cell line, biofilm formation ability and cell surface activity of the isolates. Such properties were comparatively studied, and the regression between these features was statistically analyzed. Results: Among our results 18 (42. 9%) were non-adhesive, 11 (26. 2%) moderate adhesive and 13 (31%) strongly adhesive. The results showed that some isolates were significantly capable of biofilm formation. The highest rate of auto-aggregation was recorded for L. plantarum isolate RPR 240 (58%). Conclusion: Our results revealed a high degree of variability among colonization characteristics of the L. plantarum isolates indicating strain-specificity. Also, the colonization properties of the potential probiotic isolates had no significant correlation with each other. Our results confirmed the necessity of further in vivo colonization assays for selection of probiotic candidates.

Plague is an endemic disease to the west of Iran and has frequently stricken this area over the last decades. In 1954, Pasteur Institute of Iran established a research station in the west of the country and since then has monitored the plague outbreaks as well as the disease status in rodents and carnivores by dispatching research teams to different villages and localities. We noticed that there were some valuable data from the past with no records in Journals, among them, a report of a plague outbreak in Seyed Abad village, West Azerbaijan province in 1966. During this 41-day outbreak, 22 people acquired the infection, and 11 died. Fever and buboes were the most predominant clinical symptoms in the patients. The causative agent Yersinia pestis was identified by examination of biopsies from lymph nodes, bacteriological tests, and inoculation of guinea pigs. The bubonic form of the disease and the epidemiological data suggested that the disease might have been transmitted to humans through the infective-bite of the fleas of the wild animals mainly rodents living in the vicinity of the homes of Seyed Abad village.

Introduction: Diarrheagenic Escherichia coli (DEC) including enteropathogenic (EPEC), enteroaggregative (EAEC), enterotoxigenic (ETEC), and shiga toxin producing E. coli are among the most common agents of diarrhea. There are various classes of iron uptake receptors, but there is not much data on the presence of these iron receptors in DEC isolates. The present study aimed to evaluate the presence of iron receptor genes and also hemolysis activity in these isolates. Methods: Totally, 88 DEC isolates (EAEC, ETEC, STEC, and EPEC) from a previous microbial collection were included in this study. The isolates were tested for the production of hemolysin on blood agar plates. Then, Polymerase Chain Reaction (PCR) was used for detection of iron acquisition genes, including chuA, hma, iroN, fyuA, iutA and ireA. Results: Our results showed that 8 (66. 7%), 25 (89. 3%), 17 (44. 4%) and 10 (83. 4%) of EPEC, STEC, ETEC and EAEC isolates, respectively had hemolytic activity. All the EPEC isolates were negative for hma gene, and iroN and ireA genes were absent in the EAEC isolates. The frequency of chuA, hma and fyuA genes in the STEC and EAEC isolates was higher, whereas EPEC and ETEC isolates revealed a higher frequency of iroN gene than the STEC and EAEC isolates. Conclusion: This study reports the presence of various iron receptor genes with a significant hemolysin activity in DEC isolates from Iran. The presence of these genes may contribute to the increased pathogenesis of these isolates in the intestinal tract.

Introduction: The Afghan pika (Ochotona rufescens) is a small mammal in the family Ochotonidae. This small mammal occurs in Afghanistan, Iran, Pakistan, and Turkmenistan. Here, we investigated the helminth infections among the Afghan pikas from northeastern Iran. Methods: Fourteen Afghan pikas were entrapped from Bojnord, Mashhad, Birjand, and Tandoureh in the northeast of Iran during 2013-2015. The animals were euthanized, dissected, and their gastrointestinal tracts were removed, which were then cut longitudinally, and inspected under a stereomicroscope for the presence of helminths. Also, using the formalin-ether concentration technique, the intestinal contents of the animals were examined microscopically for helminths eggs. Results: Out of 14 pikas examined, 11 (78%) harbored at least one helminth species and mixed infections with two helminths were observed in 3 (21%) animals. Four oxyurid species including Cephaluris chabaudi, Cephaluris akhtar, Fastigiuris prudhoei, and Dermatoxy schneider were identified. Also, the Oxyurid eggs were recovered from the intestinal contents of four pikas. No significant difference (P>0. 05) was observed in infection rate between male and female animals and between the areas. Conclusion: Oxyurid worms were the only prevalent infection among the Afghan pikas in northeastern Iran. The absence of other helminthic infections in pikas of the study area might be attributed to various factors like the lack of hosts species, high-elevation, and adequate moisture which facilitate the life cycle of many helminths species.

To the editor: Recent advances in genetic association (GA) studies have reported novel associations betweencommon genetic markers and human susceptibility to many major infectious diseases. In parallel, an increasing number of rare genetic variants have been identified that areassociated with susceptibility to infection. Together, theseachievements have highlighted the genetic architecture ofinfectious disease susceptibility and illuminated immuneand cellular pathways that are associated with the infectionprocess. However, for a genetic association study to yieldvalid results, particular considerations on study design andconduct are required to be taken. Application of GA studiesin the field of infectious diseases is at its early stage, callingthe need for further elaborations on design considerationsof these studies. Perhaps one of the most commonly referred approach in GA studies is to test for “ HardyWeinberg equilibrium” (HWE, described below) principle. However, this principle is frequently disregarded or missinterpreted in GA studies of infectious diseases. So, in thispiece, I would further elaborate on this concept, itsapplications, and its testing and interpretation.