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1.

Background

Northward expansion of the tick Ixodes scapularis is driving Lyme disease (LD) emergence in Canada. Information on mechanisms involved is needed to enhance surveillance and identify where LD risk is emerging.

Objectives

We used passive and active surveillance and phylogeographic analysis of Borrelia burgdorferi to investigate LD risk emergence in Quebec.

Methods

In active surveillance, we collected ticks from the environment and from captured rodents. B. burgdorferi transmission was detected by serological analysis of rodents and by polymerase chain reaction assays of ticks. Spatiotemporal trends in passive surveillance data assisted interpretation of active surveillance. Multilocus sequence typing (MLST) of B. burgdorferi in ticks identified likely source locations of B. burgdorferi.

Results

In active surveillance, we found I. scapularis at 55% of sites, and we were more likely to find them at sites with a warmer climate. B. burgdorferi was identified at 13 I. scapularis–positive sites, but infection prevalence in ticks and animal hosts was low. Low infection prevalence in ticks submitted in passive surveillance after 2004—from the tick-positive regions identified in active surveillance—coincided with an exponential increase in tick submissions during this time. MLST analysis suggested recent introduction of B. burgdorferi from the northeastern United States.

Conclusions

These data are consistent with I. scapularis ticks dispersed from the United States by migratory birds, founding populations where the climate is warmest, and then establishment of B. burgdorferi from the United States several years after I. scapularis have established. These observations provide vital information for public health to minimize the impact of LD in Canada.  相似文献   

2.

Objectives

Vibrio vunificus is known to cause septicemia and severe wound infections in patients with chronic liver diseases or an immuno-compromised condition. We carried out the molecular characterization of V. vulnificus isolates from human Vibrio septicemia cases based on pulsed-field gel electrophoresis (PFGE) using NotI and SfiI.

Methods and Results

PFGE was used to characterize a total of 78 strains from clinical cases after NotI or SfiI digestion. The geographical distribution of PFGE patterns for the strains from the southern part of Korea, a high-risk region for Vibrio septicemia, indicated that the isolates from southeastern Korea showed a comparatively higher degree of homology than those from southwestern Korea.

Conclusions

We report the genetic distribution of V. vulnficus isolated from Vibrio septicemia cases during 2000–2004 in Korea. This method has potential use as a subspecies-typing tool for V. vulnificus strains isolated from distant geographic regions.  相似文献   

3.

Background

The objectives of our research were to search for Leishmania species in rodents in Fars province, south of Iran, and to compare molecular with conventional methods for detecting these parasites.

Methods

Rodents were captured using live traps and screened for Leishmania species using molecular and conventional methods, including the taking of smears from each ear. Nested PCR was employed to detect Leishmania in rodents by amplifying a region of the ribosomal RNA amplicon of Leishmania (ITS1-5.8S rRNA-ITS2) that is species-specific by DNA sequence.

Results

Totally, 122 rodents were captured. Leishmania parasites were detected using the nested PCR and three conventional methods (direct smear, NNN culture and Balb/C inoculation. 41 (33.6%) out of 122 rodents had Leishmania infections (34 Meriones lybicus and 7 M. persicus). All PCR products of the ITS-rDNA gene were sequenced. Sequence analysis revealed that 28 out of 41 positive samples were Leishmania major. Thirteen sequences were unreadable and therefore not identified.

Conclusion

At least two gerbil species common in Fars ZCL foci, M. lybicus and M. persicus, are acquiring infections of L. major and may be reservoir hosts of one predominant parasite haplotype. Most infections were detected molecularly not by conventional methods, because most rodents died in the traps.  相似文献   

4.

Background:

Acanthamoeba castellanii forms a resistant cyst that protects the parasite against the host’s immune response. Acanthamoeba Type-I metacaspase (Acmcp) is a caspase-like protein that has been found to be expressed during the encystations. Dictyostelium discoideum is an organism closely related to Acanthamoeba useful for studying the molecular function of this protozoan caspase-like protein.

Methods:

The full length of Acmcp and a mutated version of the same gene, which lacks the proline rich N-terminal region (Acmcp-dpr), were cloned into the pDneo2a-GFP vector separately. The pDneo2a-GFP-Acmcp and pDneo2a-GFPAcmcp-dpr were electro-transfected into wild type D. discoideum cells to create cell lines that over-expressed Acmcp or Acmcp-dpr.

Results:

Both cell lines that over-expressed Acmcp and Acmcp-dpr showed a significant increase in the fluid phase internalization and phagocytosis rate compared to the control cells. Additionally, the cells expressing the Acmcp-dpr mutant were unable to initiate early development and failed to aggregate or form fruiting bodies under starvation conditions, whereas Acmcp over-expressing cells showed the opposite phenomena. Quantitative cell death analysis provided additional support for these findings.

Conclusion:

Acmcp is involved in the processes of endocytosis and phagocytosis. In addition, the proline rich region in Acmcp is important for cellular development in Dictyostelium. Given its important role in the development process, metacaspase protein is proposed as a candidate drug target against infections caused by A. castellanii.  相似文献   

5.

Background

The deficiency of SHOX gene (short stature homeobox-containing gene) has been recognized as the most frequent monogenetic cause of short stature. SHOX gene has been associated with short stature in Turner syndrome and Leri Weill dyschondrosteosis as well with non-syndromic idiopathic short stature. The aim of this study was to determine the frequency of SHOX deletions and mutations in a cohort of Slovenian children with short stature, and to delineate indications for routine SHOX gene mutation screening.

Methods and results

40 selected subjects with idiopathic short stature were screened for entire SHOX gene deletion and for mutations in the SHOX gene coding region (exon 2 to 6), together with sequences flanking the exon-intron boundaries. FISH analysis on metaphase and interphase spreads revealed no entire gene deletion. Additionally, no pathogenic point mutations or smaller deletion/duplications were identified in this study group.

Conclusions

SHOX gene deletions and point mutations are not a common cause of idiopathic short stature in a cohort of Slovenian children with short stature. Therefore, the frequency of SHOX mutations must be much lower as expected based on the reported data.  相似文献   

6.

Background:

Free-living amoebae such as Acanthamoeba species may act as carriers of Cryptosporidium and Toxoplasma oocysts, thus, may play an important role in the water-borne transmission of these parasites. In the present study, a loop mediated isothermal amplification (LAMP) method for detection of Toxoplasma and a PCR assay were developed for investigation of Acanthamoeba in environmental water samples.

Methods:

A total of 34 samples were collected from the surface water in Guilan Province. Water samples were filtrated with membrane filters and followed by DNA extraction. PCR and LAMP methods used for detection of the protozoan parasites Acanthamoeba and Toxoplasma respectively.

Results:

Totally 30 and 2 of 34 samples were positive for Acanthamoeba and Toxoplasma oocysts respectively. Two samples were positive for both investigated parasites.

Conclusion:

The investigated water supplies, are contaminated by Toxoplasma and Acanthamoeba (oo)cystes. Acanthamoeba may play an important role in water-borne transmission of Toxoplasma in the study area. For the first time in Iran, protocol of LAMP method was used effectively for the detection of Toxoplasma in surface water samples in Iran.  相似文献   

7.

Background:

Fasciola hepatica and F. gigantica are the causative agents of fasciolosis in domestic animals and humans. Based on the morphometric criteria, differential diagnosis between them is problematic. In addition, intermediate forms of Fasciola have been found in Iran, which makes the differentiation more difficult. The aim of the present study was to provide molecular evidence for the existence of F. gigantica in Iran using sequencing analysis of ND1 and PCR-RFLP analysis of ITS2 regions and to study the intraspecies variations of F. gigantica based on mitochondrial ND1 gene polymorphism.

Methods:

Forty Fasciola spp. samples collected from four distinct provinces (Fars, Khuzestan, Gilan, Khorasan Razavi) in Iran were collected for morphological and molecular characterization. In molecular method, PCR-RFLP analysis of ITS2 using pagI restriction enzyme was used as a screening approach for F. gigantica differentiation. Then mitochondrial DNA sequence variations in the ND1 gene were used for phylogenetic analysis.

Results:

Based on the morphometric criteria and RFLP analysis, 14 parasitic samples were initially identified to be F. gigantica. Phylogenetic results showed that there are at least 10 different genotypes of F. gigantica in Iran, which are different from those existing in the GenBank. Twenty-six points out of 410 base pairs of sequenced ND1 gene in 10 varieties of F. gigantica were diagnosed to be polymorphic. From 26 points of polymorphism, only eight resulted in the post-translational amino acid changes in ND1 gene product structure.

Conclusion:

Data revealed noticeable genetic diversity (up to 4.63%) between different varieties of F. gigantica in Iran.  相似文献   

8.

Background:

Coccidiosis is a serious protozoal disease of poultry. The identification of Eimeria species has important implications for diagnosis and control as well as for epidemiology. The molecular characterization of Eimeria species infecting Egyptian baladi chickens was investigated.

Methods:

Eimeria species oocysts were harvested from intestines of naturally infected Egyptian baldi chickens. The morphometry characterization of oocysts along with COCCIMORPH software was done. The DNA was extracted initially by freezing and thawing then the prepared samples was subjected to commercial DNA kits. The DNA products were analyzed through conventional polymerase chain reaction by using amplified region (SCAR) marker.

Results:

The PCR results confirmed the presence of 7 Eimeria species in the examined fecal samples of Egyptian baldi breed with their specific ampilicon sizes being E. acervulina (811bp), E. brunette (626bp), E. tenella (539bp), E. maxima (272bp), E. necatrix (200bp), E. mitis (327bp) and E. praecopx (354bp). A sequencing of the two most predominant species of Eimeria was done, on E. tenella and E. máxima. Analysis of the obtained sequences revealed high identities 99% between Egyptian isolates and the reference one. Similarly, E. maxima isolated from Egyptian baldi chickens showed 98% nucleotide identities with the reference strain. Only single nucleotide substitution was observed among the Egyptian E. tenella isolates (A181G) when compared to the reference one. The Egyptian isolates acquired 4 unique mutations (A68T, C164T, G190A and C227G) in compared with the reference sequence.

Conclusion:

This is the first time to identify the 7 species of Eimeria from Egyptian baladi chickens.  相似文献   

9.

Introduction

In May of 2012, we investigated a food-borne Clostridium perfringens outbreak in Slovenia involving a single kitchen and five venues, with 477 exposed persons.

Methods

In order to identify the causative agent, vehicle of infection and source of contamination, we conducted microbiological and environmental investigations and an analytical cohort study (n = 138).

Results

The case definition in the outbreak was met by 104 persons. Predominant symptoms were diarrhoea, nausea and abdominal cramps. Median incubation time and duration of illness were 12 and 22.5 hours respectively. Stool samples were collected from 18 persons and in 13 C. perfringens spores were present; enterotoxin was detected in 9 persons. PCR and PFGE analysis of isolates from a cook with earlier onset time, who did not consume the implicated food, and cases from four venues showed the same strain of C. perfringens type A (with cpe-gene), indistinguishable by PFGE analysis. No food samples could be obtained. An analytical study showed that one food item (French salad) was the most likely vehicle of infection (RR: 6.35; 95% CI: 1.62–24.90).

Conclusions

This was the largest C. perfringens outbreak in Slovenia to date. Proper analytical study in combination with detailed laboratory investigation with genotypisation enabled us to identify a causative agent, vehicle of infection and possible source of contamination. Fast response and interdisciplinary collaboration led to timely implementation of control measures. These have led to the kitchen acquiring new equipment and improving staff knowledge of risks and processes, thus reducing the likelihood of future reoccurrences.  相似文献   

10.

Background

Because of the strong immunologic responses of surface protein TaSp in Theileria annulata infected host, we tried to characterize this protein in a T. annulata isolate from Iran.

Methods

The RNA prepared from T. annulata infected cells was used to produce SMART-DS-cDNA. The Double strand cDNA was then amplified with primers derived from TaSp mRNA sequences. The PCR product was cloned in pTZ57R/T vector, sequenced and registered under accession no. JQ003240 in GenBank.

Results

The sequence analysis showed 90%–94% nucleotide sequence identity and 68%–94% amino acid homology to the corresponding sequences of TaSp gene by T. annulata, T. sp. china I, T. sp. china and T. lestoquardi and three T. annulata reported from Iran respectively. Interestingly, the sequence analysis also showed small nucleotide sequence region near the 5‘ end in which the presented TaSp protein differed very strongly from the other known TaSp sequences. For the preparation of the recombinant protein, the cDNA was cloned in pQE-32 vector, the recombinant protein was prepared and assayed by Theileria infected bovine serum.

Conclusion

The polymorphism in TaSp gene could be detected in intra- as well as inter species. The different characterized TaSp proteins had a common identic region, which may be helpful for development of broad band vaccine based on the recombinant proteins. The polymorphism in this gene, make this protein also interesting for the diagnostic purposes.  相似文献   

11.

Background

Toxocara is a common nematode of cats in different parts of Iran. Despite the close association of cats with human, no attempt has been done so far for molecular identification of this nematode in the country. Therefore, current study was performed on identification of some isolates of Toxocara from stray cats in Shiraz, Fars Province, Southern Iran, based on morphological and molecular approaches, and also determination of intensity of infection.

Methods

This cross-sectional study was carried out on 30 stray cats trapped from different geographical areas of Shiraz in 2011. Adult male and female worms were recovered from digestive tract after dissection of cats. Morphological features using existing keys and PCR-sequencing of ITS-rDNA region and pcox1 mitochondrial l gene were applied for the delineating the species of the parasites.

Results

Eight out of 30 cats (26.7%) were found infected with Toxocara nematodes. All the isolates were confirmed as Toxocara cati based on morphological features and the sequence of ribosomal and mitochondrial targets. Intensity of infection ranged from one to a maximum of 39 worms per cat, with a mean of 10.25±12.36, and higher abundance of female nematodes.

Conclusion

The most prevalent ascaridoid nematode of stray cats in the study area was T. cati and female nematodes were more abundant than that of males. This issue has important role in spreading of eggs in the environment and impact on human toxocariasis.  相似文献   

12.
13.

Background

Giardia duodenalis is one of the most common human intestinal protozoan parasites worldwide and is endemic throughout the world with a vast range of mammalian hosts. The present study aimed to identify the prevalence of G. duodenalis isolates and determine the most common of its assemblages in the patients referring to health centers and hospitals in Fars province, Iran that will be subjected to further molecular investigation.

Methods

We collected 1000 human fecal samples from health centers and hospitals in Shiraz, Iran in a one year period from September 2009 to August 2010. Microscopic examination for the presence of G. duodenalis cysts and trophozoites was performed by direct wet mount before and after the concentration techniques. Extraction of DNA was performed by Phenol-Chloroform-Isoamylalcohol (PCI). G. duodenalis-positive specimens were analyzed by PCR. A fragment of the SSU-rDNA (292 bp) gene was amplified by PCR using the forward primer RH11 and the reverse primer RH4. Genotyping was performed using sequence analysis of G. duodenalis glutamate dehydrogenase gene using primers GDHeF, GDHiF, and GDHiR.

Results

The prevalence of Giardia infection was 10.7% (107/1000) examined based on microscopic examination. PCR identified 80% (40/50) of the samples as positive for G. duodenalis based on SSU-rDNA amplification on sucrose gradient samples. Besides, genotyping results indicated 32 isolates (80%) as assemblage AII and 8 isolates (20%) as assemblage BIII and BIV based on the DNA sequence analysis of the glutamate dehydrogenase locus of G. duodenalis.

Conclusion

The findings of this study emphasize that Iran (Fars Province) is a favorable area for giardiasis with an anthroponotic infection route.  相似文献   

14.

Background

Cadmium (Cd) is a carcinogenic heavy metal of environmental concern. Exposure to both Cd and carcinogenic organic compounds, such as polycyclic aromatic hydrocarbons or aromatic amines (AAs), is a common environmental problem. Human arylamine N-acetyltransferases (NATs) are xenobiotic-metabolizing enzymes that play a key role in the biotransformation of AA carcinogens. Changes in NAT activity have long been associated with variations in susceptibility to different cancers in relation with exposure to certain AAs.

Objective

We explored the possible interactions between Cd and the NAT-dependent biotransformation of carcinogenic AAs.

Methods

We exposed purified enzymes, lung epithelial cells, and mouse models to Cd and subsequently analyzed NAT-dependent metabolism of AAs.

Results

We found that Cd, at biologically relevant concentrations, impairs the NAT-dependent acetylation of carcinogenic AAs such as 2-aminofluorene (2-AF) in lung epithelial cells. NAT activity was strongly impaired in the tissues of mice exposed to Cd. Accordingly, mice exposed to Cd and 2-AF displayed altered in vivo toxicokinetics with a significant decrease (~ 50%) in acetylated 2-AF in plasma. We found that human NAT1 was rapidly and irreversibly inhibited by Cd [median inhibitory concentration (IC50) ≈ 55 nM; rate inhibition constant (kinact) = 5 × 104 M−1 · sec−1], with results of acetyl coenzyme A (acetyl-CoA) protection assays indicating that Cd-mediated inhibition was due to the reaction of metal with the active-site cysteine residue of the enzyme. We found similar results for human NAT2, although this isoform was less sensitive to inactivation (IC50 ≈ 1 μM; kinact = 1 × 104 M−1 · sec−1).

Conclusions

Our data suggest that Cd can alter the metabolism of carcinogenic AAs through the impairment of the NAT-dependent pathway, which may have important toxicological consequences.  相似文献   

15.

Objectives

Vivax malaria has reemerged and become endemic in Korea. Our study aimed to analyze by both longitudinal and cross-sectional genetic diversity of this malaria based on the P vivax Merozoite Surface Protein (PvMSP) gene parasites recently found in the Korean peninsula.

Methods

PvMSP-1 gene sequence analysis from P vivax isolates (n = 835) during the 1996-2010 period were longitudinally analyzed and the isolates from the Korean peninsula through South Korea, the demilitarized zone and North Korea collected in 2008-2010 were enrolled in an overall analysis of MSP-1 gene diversity.

Results

New recombinant subtypes and severe multiple-cloneinfection rates were observed in recent vivax parasites. Regional variation was also observed in the study sites.

Conclusion

This study revealed the great complexity of genetic variation and rapid dissemination of genes in P vivax. It also showed interesting patterns of diversity depending, on the region in the Korean Peninsula. Understanding the parasiteninsula. Under genetic variation may help to analyze trends and assess the extent of endemic malaria in Korea.  相似文献   

16.
17.

Background

Staphylococcus aureus, especially Methicillin Resistant Staphylococcus Aureus (MRSA) is a major health problem recognized as the most important nosocomial pathogen, often causing postoperative wound infections. Antibiotic resistance by MRSA has grown to be common, and resistance to almost all antibiotics has been found among these strains. The aim of this study was to determine the prevalence, antimicrobial susceptibility patterns and associated risk factors of S. aureus in patients with surgical site infections in an Ethiopian hospital.

Methods

A cross-sectional study was conducted from December 1, 2011 to March 30, 2012 among patients with surgical site infections at Debre Markos Referral Hospital, Debre Markos, Ethiopia. All wound swabs obtained from patients with surgical site infections during the study period were cultured on mannitol salt agar media which is selective for S. aureus. Isolated strains of S. aureus were tested for antibiotic susceptibility patterns using standard disc diffusion technique, and interpretation of resistance was done based on Clinical and Laboratory Standard Institute criteria. Univariate and multivariable analyses were used to assess the risk factors.

Results

Of the 184 surgical patients who had developed surgical site infection, S. aureus was isolated from 73 (39.7%) cases. Out of the 73 isolates of S. aureus, 36 (49.7%) were MRSA. Among the study participants, prevalence of MRSA was found to be 19.6%. The clinical isolates showed >80% level of resistance to ampicillin, amoxicillin, penicillin G, erythromycin, gentamicin and cotrimoxazole whereas <50% level of resistance was observed against clindamycin, oxacillin, tetracycline and vancomycin. MRSA strains showed resistance ranging from 5.6% (vancomycin) to 100% (cotrimoxazole). Of the following risk factors: sex, age, pus consistency, duration of operation, type of surgery, ward and hospital stay, laparotomy type of surgery was identified as a risk factor for infection by S. aureus.

Conclusion

The prevalence of S. aureus and/or MRSA infection in surgical and gynaecology & obstetrics wards of Debre Markos Referral Hospital was found to be high. The majority of isolates were highly resistant to major antimicrobial agents.  相似文献   

18.

Objectives

To investigate the possible link between Vibrio vulnificus population size in seawater and water temperature.

Methods

We collected incidence and water temperature data in coastal regions of Korea and constructed a mathematical model that consisted of three classes; susceptible fish, infected fish available to humans, and infected humans.

Results

We developed a mathematical model to connect V. vulnificus incidence with water temperature using estimated bacterial population sizes and actual coastal water temperatures.

Conclusion

Increased V. vulnificus population sizes in marine environments may increase the risk of infection in people who eat at coastal restaurants in Korea. Furthermore, we estimated the near-future number of infected patients using our model, which will help to establish a public-health policy to reduce the disease burden.  相似文献   

19.

Background

The differentiation between acute and latent forms of the Toxoplasma gondii (T. gondii) infection is still considered as a complicated issue. This study was aimed to elucidate the status of infection in the blood donors and the probable importance of blood transfusion in the transmission of the infection through detecting both immunological and genetic markers of acute and latent infection.

Methods

Totally 235 blood samples from blood donors were collected. The levels of anti-T. gondii IgG and IgM antibodies were examined by specific ELISA kits. cDNA were synthesized from total extracted mRNA molecules from the serum samples and SAG1 gene, specific for tachyzoite form, were amplified using Real-Time PCR technique. Demographic information of study subjects including their gender, age, job, and habitat were recorded.

Results

Out of 235 serum samples, 80 (34.04%) and 4 (1.71%) were positive regarding anti-T. gondii IgG and IgM antibodies, respectively. Real-Time PCR results showed that 14 out of 200 (6.97%) of blood donor had mRNA molecules of SAG1 gene. The positive results of Real-Time PCR of SAG1 in female gender and housekeepers were significantly higher than those of male gender and other job categories.

Conclusion

The prevalence of chronic and acute infection is high in Iranian blood donors. Additionally, evaluation of antibodies could not be reliable, because several donors negative for anti-T. gondii IgM antibodies had detectable SAG1 mRNA molecules. Hence, it seems that molecular diagnostic tests are essential to detect acute infections.  相似文献   

20.

Objectives:

In Fujian Province, China, gastric cancer is one of the leading causes of mortality among all malignant tumors. Nanjing county and Minqing county are located in inland Fujian and have similar general demographics. However, the adjusted mortality rate of gastric cancer in Minqing was found to be much higher than that in Nanjing. We sought to explore factors associated with this increased risk of gastric cancer between the two counties.

Methods:

We recruited 231 and 224 residents from Nanjing and Minqing, respectively, and analyzed differences between their dietary habits, Helicobacter pylori infection rates, and concentrations of serum pepsinogen I, pepsinogen II, gastrin-17, and ratio of pepsinogen I:II.

Results:

Subjects in Minqing had more first-degree relatives who had been diagnosed with upper gastrointestinal tumor, more unhealthy dietary habits, a higher Helicobacter pylori positive rate, and greater proportion of abnormal serum gastrin-17 than those in Nanjing did.

Conclusions:

The factors that differed between these two counties might indicate that residents in Minqing have a higher risk for developing gastric cancer than those in Nanjing do.  相似文献   

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