Journal of Pathogens

Probiotics as Antiviral Agents in Shrimp Aquaculture

Bestha Lakshmi, Buddolla Viswanath, and D. V. R. Sai Gopal — Tue, 30 Apr 2013 09:17:44 +0000

Shrimp farming is an aquaculture business for the cultivation of marine shrimps or prawns for human consumption and is now considered as a major economic and food production sector as it is an increasingly important source of protein available for human consumption. Intensification of shrimp farming had led to the development of a number of diseases, which resulted in the excessive use of antimicrobial agents, which is finally responsible for many adverse effects. Currently, probiotics are chosen as the best alternatives to these antimicrobial agents and they act as natural immune enhancers, which provoke the disease resistance in shrimp farm. Viral diseases stand as the major constraint causing an enormous loss in the production in shrimp farms. Probiotics besides being beneficial bacteria also possess antiviral activity. Exploitation of these probiotics in treatment and prevention of viral diseases in shrimp aquaculture is a novel and efficient method. This review discusses the benefits of probiotics and their criteria for selection in shrimp aquaculture and their role in immune power enhancement towards viral diseases.

Seroepidemiology of Helicobacter pylori Infection in Tepehuanos Aged 15 Years and Older in Durango, Mexico

Cosme Alvarado-Esquivel — Wed, 20 Mar 2013 09:01:44 +0000

This study aimed to determine the seroepidemiology of Helicobacter pylori infection in Tepehuanos (an indigenous ethnic group living in rural Mexico). The prevalence of anti-Helicobacter pylori IgG antibodies was examined in 156 Tepehuanos in Durango State, Mexico, using an enzyme-linked immunoassay. In addition, sociodemographic, clinical, and behavioral characteristics of Tepehuanos associated with seropositivity were investigated. In total, 103 (66%) of the 156 participants (mean age years) had Helicobacter pylori IgG antibodies. Fifty-four (52.4%) of the 103 seropositive individuals had Helicobacter pylori IgG antibody levels higher than 100 U/mL. Males and females had comparable seroprevalence of Helicobacter pylori infection and Helicobacter pylori IgG antibody levels. The seroprevalence was significantly higher in women with pregnancies than those without this obstetric characteristic. Logistic regression showed that Helicobacter pylori infection was positively associated with low education (OR = 3.37; 95% CI: 1.13–10.00; ) and laborer occupation (OR = 2.71; 95% CI: 1.14–6.42; ). This is the first report of seroprevalence and contributing factors for Helicobacter pylori infection in Tepehuanos and of the association of Helicobacter pylori infection with laborer occupation. Results warrants further research.

Toxoplasmosis and Polygenic Disease Susceptibility Genes: Extensive Toxoplasma gondii Host/Pathogen Interactome Enrichment in Nine Psychiatric or Neurological Disorders

C. J. Carter — Mon, 04 Mar 2013 15:00:02 +0000

Toxoplasma gondii is not only implicated in schizophrenia and related disorders, but also in Alzheimer's or Parkinson's disease, cancer, cardiac myopathies, and autoimmune disorders. During its life cycle, the pathogen interacts with ~3000 host genes or proteins. Susceptibility genes for multiple sclerosis, Alzheimer's disease, schizophrenia, bipolar disorder, depression, childhood obesity, Parkinson's disease, attention deficit hyperactivity disorder (multiple sclerosis), and autism (), but not anorexia or chronic fatigue are highly enriched in the human arm of this interactome and 18 (ADHD) to 33% (MS) of the susceptibility genes relate to it. The signalling pathways involved in the susceptibility gene/interactome overlaps are relatively specific and relevant to each disease suggesting a means whereby susceptibility genes could orient the attentions of a single pathogen towards disruption of the specific pathways that together contribute (positively or negatively) to the endophenotypes of different diseases. Conditional protein knockdown, orchestrated by T. gondii proteins or antibodies binding to those of the host (pathogen derived autoimmunity) and metabolite exchange, may contribute to this disruption. Susceptibility genes may thus be related to the causes and influencers of disease, rather than (and as well as) to the disease itself.

Experimental Airborne Transmission of Porcine Postweaning Multisystemic Wasting Syndrome

Thu, 07 Feb 2013 10:23:19 +0000

The objective of these studies was to investigate if porcine postweaning multisystemic wasting syndrome (PMWS) could be induced in healthy pigs following contact with air from pigs with clinical signs of PMWS. The pigs were housed in different units. Either 31 (study I) or 25 (study II) pigs with clinical symptoms of PMWS from a PMWS-affected herd and 25 healthy pigs from a PMWS-free, but PCV2-positive, herd were housed in unit A. Fifty pigs from a PMWS-free herd were housed in unit B, which were connected by pipes to unit A. In unit C, 30 pigs from a PMWS-free herd were housed as controls. In study II, the pigs in units A and B from the PMWS-free herd developed clinical signs of PMWS 2-3 weeks after arrival. PMWS was confirmed at necropsy and the diseased pigs had increased PCV2 load and increased antibody titers against PCV2 in serum that coincided with the development of clinical signs typical of PMWS. Sequence analysis revealed that the PCV2 isolate belonged to genotype 2b. In conclusion, the present study showed that PMWS can be induced in pigs from a PMWS-free herd by airborne contact with pigs from a PMWS-affected herd.

Monitoring of Active Human Herpes Virus 6 Infection in Iranian Patients with Different Subtypes of Multiple Sclerosis

Tue, 22 Jan 2013 13:13:19 +0000

Background. Recently, it has been suggested that human herpes virus 6 (HHV6) may play a role in the pathogenesis of multiple sclerosis (MS). Our purpose is to determine the incidence of reactivated HHV6 in MS patients. Methods. Viral sequence analyzed by qPCR in the peripheral blood mononuclear cells (PBMCs), serum, and saliva samples of different subtypes of MS patients () and healthy controls (). HHV6 IgG and IgM antibody levels measured by ELISA technique in the plasma samples of both groups. Likewise, cerebrospinal fluid (CSF) samples of some MS patients () were analyzed for viral sequence. Results. Results demonstrate increased levels of anti-HHV6-IgG (78.2% versus 76.4% in controls; ), and IgM (34.6% versus 6.5% in controls; ) in MS patients. Furthermore, RRMS and SPMS patients showed relatively higher anti-HHV6 IgG and IgM compared to PPMS (). Moreover, load of cell-free viral DNA was higher in RRMS and SPMS patients and detected in 60.2% (47/78) of MS patients, compared with 14.6% (18/123) of healthy controls (). Moreover, load of cell-free viral DNA was higher in RRMS and SPMS patients and detected in 60.2% (47/78) of MS patients, compared with 14.6% (18/123) of healthy controls (). Conclusions. The results extend the observation of an increased frequency of systemic reactivated HHV6 infection in MS patients with developed stages of disease.

Aerobiology and Its Role in the Transmission of Infectious Diseases

Aaron Fernstrom and Michael Goldblatt — Sun, 13 Jan 2013 09:10:16 +0000

Aerobiology plays a fundamental role in the transmission of infectious diseases. As infectious disease and infection control practitioners continue employing contemporary techniques (e.g., computational fluid dynamics to study particle flow, polymerase chain reaction methodologies to quantify particle concentrations in various settings, and epidemiology to track the spread of disease), the central variables affecting the airborne transmission of pathogens are becoming better known. This paper reviews many of these aerobiological variables (e.g., particle size, particle type, the duration that particles can remain airborne, the distance that particles can travel, and meteorological and environmental factors), as well as the common origins of these infectious particles. We then review several real-world settings with known difficulties controlling the airborne transmission of infectious particles (e.g., office buildings, healthcare facilities, and commercial airplanes), while detailing the respective measures each of these industries is undertaking in its effort to ameliorate the transmission of airborne infectious diseases.

Clinical and Microbiological Profile of HIV/AIDS Cases with Diarrhea in North India

Thu, 27 Dec 2012 18:10:01 +0000

Intestinal infections are a significant cause of morbidity and mortality in people living with HIV/AIDS (PLWHA) especially in developing countries. The present study was conducted to assess the clinical and microbiological spectrum in HIV/AIDS cases with diarrhea and to correlate the occurrence of such pathogens with stool characters, HIV seropositivity status, and CD4 counts. Stools from 154 HIV seropositive subjects and 50 HIV negative controls were examined by direct microscopy, fecal cultures, and serological tests (Clostridium difficile Toxin A, Cryptosporidium antigen, and Entamoeba histolytica antigen ELISA). CD4 T cell enumeration was done using FACS count (Becton Dickinson). The study showed a male preponderance (112 males and 42 females). Weakness, abdominal pain, and anorexia were the most common symptoms. Coccidian parasites were the most common cause of diarrhea in HIV seropositive cases. C. parvum was seen in 60.42% while Isospora belli in 9.03%. Amongst the bacterial pathogens C. difficile was detected in 18.06%, diarrheagenic Escherichia coli in 11.11%, and Shigella spp. in 2.78%. Pathogen isolation rates were more in HIV seropositive cases and subjects with low CD4 T lymphocyte counts. Regular monitoring of CD4 T lymphocyte counts and screening for enteric pathogens will help improve the quality of life for PLWHA.

Design and Construction of a Single-Tube, LATE-PCR, Multiplex Endpoint Assay with Lights-On/Lights-Off Probes for the Detection of Pathogens Associated with Sepsis

Wed, 26 Dec 2012 14:34:45 +0000

Aims. The goal of this study was to construct a single tube molecular diagnostic multiplex assay for the detection of microbial pathogens commonly associated with septicemia, using LATE-PCR and Lights-On/Lights-Off probe technology. Methods and Results. The assay described here identified pathogens associated with sepsis by amplification and analysis of the 16S ribosomal DNA gene sequence for bacteria and specific gene sequences for fungi. A sequence from an unidentified gene in Lactococcus lactis subsp. cremoris served as a positive control for assay function. LATE-PCR was used to generate single-stranded amplicons that were then analyzed at endpoint over a wide temperature range in a specific fluorescent color. Each bacterial target was identified by its pattern of hybridization to Lights-On/Lights-Off probes derived from molecular beacons. Complex mixtures of targets were also detected. Conclusions. All microbial targets were identified in samples containing low starting copy numbers of pathogen genomic DNA, both as individual targets and in complex mixtures. Significance and Impact of the Study. This assay uses new technology to achieve an advance in the field of molecular diagnostics: a single-tube multiplex assay for identification of pathogens commonly associated with sepsis.

Identification at Biovar Level of Brucella Isolates Causing Abortion in Small Ruminants of Iran

Tue, 27 Nov 2012 16:17:22 +0000

To determine the most prevalent biovar responsible for brucellosis in sheep and goat populations of Iran, a cross-sectional study was carried out over 2 years in six provinces selected based on geography and disease prevalence. Specimens obtained from referred aborted sheep and goat fetuses were cultured on Brucella selective media for microbiological isolation. Brucellae were isolated from 265 fetuses and examined for biovar identification using standard microbiological methods. Results showed that 246 isolates (92.8%) were B. melitensis biovar 1, 18 isolates (6.8%) were B. melitensis biovar 2, and, interestingly, one isolate (0.4%) obtained from Mazandaran province was B. abortus biovar 3. In this study, B. melitensis biovar 3 was isolated in none of the selected provinces, and all isolates from 3 provinces (i.e., Chehar-mahal Bakhtiari, Markazi, and Ilam) were identified only as B. melitensis biovar 1. In conclusion, we found that B. melitensis biovar 1 remains the most prevalent cause of small ruminant brucellosis in various provinces of Iran.

Lipid Droplets and Mycobacterium leprae Infection

Ayssar A. Elamin, Matthias Stehr, and Mahavir Singh — Mon, 12 Nov 2012 15:10:19 +0000

Leprosy is a chronic infectious disease and is a major source of morbidity in developing countries. Leprosy is caused by the obligate intracellular bacterium Mycobacterium leprae, which infects as primary target Schwann cells. Lepromatous leprosy exhibits multiple lesions of the skin, eyes, nerves, and lymph nodes. The sites of infection are characterized by the presence of foamy macrophages, fully packed with lipid droplets (LDs), which are induced by M. leprae. In the last years, it has become evident that M. tuberculosis imports lipids from foamy macrophages and is dependent on fatty acids for growth in infected macrophages. M. leprae seems to have similar mechanisms for scavenging lipids from the host. But due to the inability to culture M. leprae on laboratory media, research progresses only slowly. However, in the last years, substantial progress has been made in the field of lipid metabolism in M. leprae. Herein, we will present and summarize the lipid droplets formation and the metabolism of lipids during M. leprae infection.

A New Generation Microarray for the Simultaneous Detection and Identification of Yersinia pestis and Bacillus anthracis in Food

Noriko Goji, Trevor MacMillan, and Kingsley Kwaku Amoako — Thu, 18 Oct 2012 08:53:37 +0000

The use of microarrays as a multiple analytic system has generated increased interest and provided a powerful analytical tool for the simultaneous detection of pathogens in a single experiment. A wide array of applications for this technology has been reported. A low density oligonucleotide microarray was generated from the genetic sequences of Y. pestis and B. anthracis and used to fabricate a microarray chip. The new generation chip, consisting of 2,240 spots in 4 quadrants with the capability of stripping/rehybridization, was designated as “Y-PESTIS/B-ANTHRACIS 4x2K Array.” The chip was tested for specificity using DNA from a panel of bacteria that may be potentially present in food. In all, 37 unique Y. pestis-specific and 83 B. anthracis-specific probes were identified. The microarray assay distinguished Y. pestis and B. anthracis from the other bacterial species tested and correctly identified the Y. pestis-specific oligonucleotide probes using DNA extracted from experimentally inoculated milk samples. Using a whole genome amplification method, the assay was able to detect as low as 1 ng genomic DNA as the start sample. The results suggest that oligonucleotide microarray can specifically detect and identify Y. pestis and B. anthracis and may be a potentially useful diagnostic tool for detecting and confirming the organisms in food during a bioterrorism event.

Human Sperm Interaction with Staphylococcus aureus: A Molecular Approach

Sonia Gupta and Vijay Prabha — Mon, 15 Oct 2012 09:17:46 +0000

Sperm immobilization factor (SIF) causing 100% immobilization of spermatozoa isolated from Staphylococcus aureus when characterized using LC-MS (Liquid chromatography-mass spectrometry) showed that this 20 kDa protein had peptide sequence similarity with hsp-70 protein. It was found to completely (100%) inhibit Mg++ ATPase activity of spermatozoa at concentration of 100 μg mL−1. Sperm samples treated with SIF also showed reduction in calcium ionophore-induced acrosome reaction as compared to control samples (treated with calcium ionophore alone). Binding studies of FITC labelled SIF with spermatozoa using fluorescent microscopy showed binding of SIF to the surface of spermatozoa indicating the presence of SIF binding receptor. The receptor was extracted by 3M NaCl and purified by gel permeation chromatography. Characterization of the receptor by MALDI-TOF (Matrix-assisted laser desorption ionization-time of flight) indicated that the receptor shared sequence similarity with MHC class II antigen. A calorimetric study showed that the receptor moiety on spermatozoa was specific for the purified ligand as binding of the receptor to ligand was enthalpically (−11.9 kJ mole−1) as well as entropically (21.53 J mole−1 K−1) favored resulting in the Gibb's free energy of −18.57 kJ mole−1.

Understanding Viral Transmission Behavior via Protein Intrinsic Disorder Prediction: Coronaviruses

Gerard Kian-Meng Goh, A. Keith Dunker, and Vladimir N. Uversky — Sun, 14 Oct 2012 08:32:24 +0000

Besides being a common threat to farm animals and poultry, coronavirus (CoV) was responsible for the human severe acute respiratory syndrome (SARS) epidemic in 2002–4. However, many aspects of CoV behavior, including modes of its transmission, are yet to be fully understood. We show that the amount and the peculiarities of distribution of the protein intrinsic disorder in the viral shell can be used for the efficient analysis of the behavior and transmission modes of CoV. The proposed model allows categorization of the various CoVs by the peculiarities of disorder distribution in their membrane (M) and nucleocapsid (N). This categorization enables quick identification of viruses with similar behaviors in transmission, regardless of genetic proximity. Based on this analysis, an empirical model for predicting the viral transmission behavior is developed. This model is able to explain some behavioral aspects of important coronaviruses that previously were not fully understood. The new predictor can be a useful tool for better epidemiological, clinical, and structural understanding of behavior of both newly emerging viruses and viruses that have been known for a long time. A potentially new vaccine strategy could involve searches for viral strains that are characterized by the evolutionary misfit between the peculiarities of the disorder distribution in their shells and their behavior.

Rapid Detection and Identification of Yersinia pestis from Food Using Immunomagnetic Separation and Pyrosequencing

Wed, 03 Oct 2012 11:39:35 +0000

Interest has recently been renewed in the possible use of Y. pestis, the causative agent of plague, as a biological weapon by terrorists. The vulnerability of food to intentional contamination coupled with reports of humans having acquired plague through eating infected animals that were not adequately cooked or handling of meat from infected animals makes the possible use of Y. pestis in a foodborne bioterrorism attack a reality. Rapid, efficient food sample preparation and detection systems that will help overcome the problem associated with the complexity of the different matrices and also remove any ambiguity in results will enable rapid informed decisions to be made regarding contamination of food with biothreat agents. We have developed a rapid detection assay that combines the use of immunomagnetic separation and pyrosequencing in generating results for the unambiguous identification of Y. pestis from milk (0.9 CFU/mL), bagged salad (1.6 CFU/g), and processed meat (10 CFU/g). The low detection limits demonstrated in this assay provide a novel tool for the rapid detection and confirmation of Y. pestis in food without the need for enrichment. The combined use of the iCropTheBug system and pyrosequencing for efficient capture and detection of Y. pestis is novel and has potential applications in food biodefence.

Bacteria Isolations from Broiler and Layer Chicks in Zambia

Mon, 03 Sep 2012 13:40:35 +0000

Chick mortality (CM) is one of the major constraints to the expansion of the poultry industry in Zambia. Of the 2,829 avian disease cases submitted to the national diagnostic laboratory based at the Central Veterinary Research Institute in Lusaka between 1995 and 2007, 34.39% (973/2,829) were from CM cases. The disease accounted for 40.2% (218,787/544,903) mortality in the affected flocks with 89.6% (196,112/218,787) of the affected birds dying within seven days. Major bacteria species involved were Escherichia coli, Salmonella gallinarum, and Proteus species being isolated from 84.58%, 46.15%, and 26.93% of the reported CM cases (𝑛=973), respectively. Detection of Salmonella typhimurium, Salmonella enteritidis, and Salmonella dublin indicates that poultry has the potential of transmitting zoonotic pathogenic bacteria to humans. The proportion of Salmonella gallinarum reactors in the adult breeding stock was generally low (<0.5%) throughout the study period although its prevalence in CM cases was correlated (𝑟=0.68, 𝑃<0.011) with seroprevalence of the same pathogen in the adult breeding stock. Given that the disease accounts for a large proportion of the avian diseases in Zambia as shown in the present study (34.39%, 𝑛=2,829), it is imperative that an effective disease control strategy aimed at reducing its occurrence should be developed.

Eleven-Year Distribution Pattern of Hepatitis C Virus in Southern Italy

Thu, 09 Aug 2012 14:27:28 +0000

Analysis of the Hepatitis C Virus (HCV) genotype spread in a particular area has a crucial impact on public health. In this study, we update information on the distribution of HCV genotypes, by evaluating a hospital-based cohort of 2,153 chronic hepatitis C patients, collected prospectively among subjects attending University Hospital of Catanzaro, within an area of Southern Italy. We assessed the rates (%) of HCV genotypes during two consecutive periods, from 2001 to 2005 and from 2006 to 2011, according to age and gender. Considering overall observation time, subtype 1b was predominant followed by subtypes 2a/2c, genotype 3 and 4. Statistical evaluation of the age of HCV patients stratified by genotypes, revealed a slight but significant increase in the median age of 1b, 2a/2c and 3 HCV genotype-infected subjects, during the 2006–2011 period, whilst genotype 4 patients exhibited a decrease in the median age during the same period studied. Moreover genotype 4 increased between 2002 and 2003 as well as between 2010 and 2011. Due to the peculiar diagnostic/clinical/therapeutic features of HCV-4, our findings warrant a deeper investigation to better control infections caused by such genotype.

Detection and Quantification of Legionella pneumophila from Water Systems in Kuwait Residential Facilities

Tue, 24 Jul 2012 08:05:33 +0000

The prevalence of Legionella pneumophilia in water systems of residential facilities in Kuwait was performed during the period from November 2007 to November 2011. A total of 204 water samples collected from faucets and showerheads in bathrooms (n = 82), taps in kitchens (n = 51), and water tanks (n = 71), from different locations of residential facilities in Kuwait were screened for Legionella pneumophila by the standard culture method and by real time polymerase chain reaction (RT-PCR). Out of the 204 samples, 89 (43.6%) samples were positive for Legionella spp., 48 (23.5%) samples were detected by the standard culture method, and 85 (41.7%) were detected by RT-PCR. Of the culture positive Legionella samples, counts ranged between 10 to 2250 CFU/L. Serological typing of 48 Legionella isolates revealed that 6 (12.5%) of these isolates belonged to Legionella pneumophila serogroup 1, 37 (77.1%) isolates to Legionella pneumophila serogroup 3, and 1 isolate each (2.1%) belonged to serogroups 4, 7, and 10. The minimum inhibitory concentration (MICs) of the 46 environmental L. pneumophila isolates against the 10 antimicrobials commonly used for Legionella infection treatments were determined. Rifampicin was found to be the most active against L. pneumophila serogroups isolates in vitro.

Yersiniosis and Food Safety

Latiful Bari, Dike O. Ukuku, Kenji Isshiki, Ramesh C. Ray, and Didier Montet — Tue, 20 Mar 2012 16:21:32 +0000

Averting Behavior Framework for Perceived Risk of Yersinia enterocolitica Infections

Sonia N. Aziz and Khwaja M. S. Aziz — Wed, 07 Mar 2012 08:38:23 +0000

The focus of this research is to present a theoretical model of averting actions that households take to avoid exposure to Yersinia enterocolitica in contaminated food. The cost of illness approach only takes into account the value of a cure, while the averting behavior approach can estimate the value of preventing the illness. The household, rather than the individual, is the unit of analysis in this model, where one household member is primarily responsible for procuring uncontaminated food for their family. Since children are particularly susceptible and live with parents who are primary decision makers for sustenance, the designated household head makes the choices that are investigated in this paper. This model uses constrained optimization to characterize activities that may offer protection from exposure to Yersinia enterocolitica contaminated food. A representative household decision maker is assumed to allocate family resources to maximize utility of an altruistic parent, an assumption used in most research involving economics of the family.

Myco-Biocontrol of Insect Pests: Factors Involved, Mechanism, and Regulation

Thu, 23 Feb 2012 11:47:20 +0000

The growing demand for reducing chemical inputs in agriculture and increased resistance to insecticides have provided great impetus to the development of alternative forms of insect-pest control. Myco-biocontrol offers an attractive alternative to the use of chemical pesticides. Myco-biocontrol agents are naturally occurring organisms which are perceived as less damaging to the environment. Their mode of action appears little complex which makes it highly unlikely that resistance could be developed to a biopesticide. Past research has shown some promise of the use of fungi as a selective pesticide. The current paper updates us about the recent progress in the field of myco-biocontrol of insect pests and their possible mechanism of action to further enhance our understanding about the biological control of insect pests.

Comparative Analyses of Exoproteinases Produced by Three Phytopathogenic Microorganisms

Wed, 14 Dec 2011 13:43:19 +0000

Proteinases secreted by the oomycete Phytophthora infestans (Mont.) de Bary, Rhizoctonia solani, and Fusarium culmorum belonging to different families of fungi have been studied to determine if the exoenzyme secretion depends on the environmental conditions and the phylogenetic position of the pathogen. The substrate specificity of the extracellular proteinases of F. culmorum, R. solani, and P. infestans and their sensitivity to the action of synthetic and protein inhibitors suggest that they contain trypsin-like and subtilisin-like enzymes regardless of culture medium composition. The relation of trypsin-like and subtilisin-like enzymes is dependent on the culture medium composition, especially on the form of nitrogen nutrition, particularly in the case of the exoenzymes secreted by R. solani. Phylogenetic analyses have shown that the exoproteinase set of ascomycetes and oomycetes has more similarities than basidiomycetes although they are more distant relatives. Our data suggests that the multiple proteinases secreted by pathogenic fungi could play different roles in pathogenesis, increasing the adaptability and host range, or could have different functions in survival in various ecological habitats outside the host.

Structural and Biochemical Changes in Salicylic-Acid-Treated Date Palm Roots Challenged with Fusarium oxysporum f. sp. albedinis

Wed, 07 Dec 2011 14:59:56 +0000

Histochemical and ultrastructural analyses were carried out to assess structural and biochemical changes in date palm roots pretreated with salicylic acid (SA) then inoculated with Fusarium oxysporum f. sp. albedinis (Foa). Flavonoids, induced proteins, and peroxidase activity were revealed in root tissues of SA-treated plants after challenge by Foa. These reactions were closely associated with plant resistance to Foa. Host reactions induced after inoculation of SA-treated plants with Foa included the plugging of intercellular spaces, the deposition of electron-dense materials at the sites of pathogen penetration, and several damages to fungal cells. On the other hand, untreated inoculated plants showed marked cell wall degradation and total cytoplasm disorganization, indicating the protective effects provided by salicylic acid in treated plants.

A Novel msDNA (Multicopy Single-Stranded DNA) Strain Present in Yersinia frederiksenii ATCC 33641 Contig01029 Enteropathogenic Bacteria with the Genomic Analysis of It's Retron

Rasel Das, Tadashi Shimamoto, and Md. Arifuzzaman — Thu, 17 Nov 2011 14:00:16 +0000

Retron is a retroelement that encodes msDNA (multicopy single-stranded DNA) which was significantly found mainly in Gram-negative pathogenic bacteria. We screened Yersinia frederiksenii ATCC 33641 contig01029 for the presence of retroelement by using bioinformatics tools and characterized a novel retron-Yf79 on the chromosome that encodes msDNA-Yf79. In this study, we perceived that, the codon usage of retron-Yf79 were noteworthy different from those of the Y. frederiksenii genome. It demonstrates that, the retron-Yf79 was a foreign DNA element and integrated into this organism genome during their evolution. In addition to this, we have observed a transposase gene which is located just downstream of retron-Yf79. So, the enzyme might be responsible for the transposition of this novel retron element.

Leptospirosis Prevalence in a Population of Yucatan, Mexico

Wed, 02 Nov 2011 14:33:35 +0000

Objective. To measure the prevalence of leptospirosis with two techniques in inhabitants of Izamal, Yucatan and to determine its relation with some exposure factors. Material and Methods. Transversal study in populations belonging to the HR62—IMSS-Opportunities working force in Izamal, Yucatan. Population, including 6 years of age or more, was randomly selected to participate in the study. A questionnaire was applied for personal ID and exposure factors; blood samples were taken for leptospirosis diagnosis. Simple frequencies, proportions, tendency and dispersion measures, prevalence and odd ratios and confidence intervals (CI) of 95%, and logistic regression model were obtained. Results. 204 patients, between 9 and 80 years old were included; 180 were positive (88.2%) with the dark-field technique; using MAT cutoff at 1∶40, 178 patients (87.3%) were positive, while at 1∶80 there were 103 positive (50.5%). The predominant serovar was Hardjo (94%). The highest prevalence was in women (96.3%) and in the >45-year-old group (95.7%); feminine gender (RM = 2.31 IC 95% 3.59–28.6), housewife (RM = 22.8 IC 95% 4.9–106.1), being in contact with stagnant water (RM = 5.2 IC 95% 1.7–15.9), and being in contact with domestic animal feces (RM = 5.1 IC 95% 1.9–13.1), these being the most significant variables in the final logistic regression model. Conclusions. The prevalence found was higher than the one nationally and internationally reported, representing an important finding, being in turn a local public health, maybe nationally. It is urgent to reinforce this research as well as to establish preventive and control measure to avoid exposure and health damages.

Recent Advances in Molecular Technologies and Their Application in Pathogen Detection in Foods with Particular Reference to Yersinia

Jin Gui and Isha R. Patel — Sat, 29 Oct 2011 17:28:21 +0000

Yersinia enterocolitica is an important zoonotic pathogen that can cause yersiniosis in humans and animals. Food has been suggested to be the main source of yersiniosis. It is critical for the researchers to be able to detect Yersinia or any other foodborne pathogen with increased sensitivity and specificity, as well as in real-time, in the case of a foodborne disease outbreak. Conventional detection methods are known to be labor intensive, time consuming, or expensive. On the other hand, more sensitive molecular-based detection methods like next generation sequencing, microarray, and many others are capable of providing faster results. DNA testing is now possible on a single molecule, and high-throughput analysis allows multiple detection reactions to be performed at once, thus allowing a range of characteristics to be rapidly and simultaneously determined. Despite better detection efficiencies, results derived using molecular biology methods can be affected by the various food matrixes. With the improvements in sample preparation, data analysis, and testing procedures, molecular detection techniques will likely continue to simplify and increase the speed of detection while simultaneously improving the sensitivity and specificity for tracking pathogens in food matrices.

The Poplar-Poplar Rust Interaction: Insights from Genomics and Transcriptomics

Wed, 26 Oct 2011 15:58:59 +0000

Poplars are extensively cultivated worldwide, and their susceptibility to the leaf rust fungus Melampsora larici-populina leads to considerable damages in plantations. Despite a good knowledge of the poplar rust life cycle, and particularly the epidemics on poplar, the perennial status of the plant host and the obligate biotrophic lifestyle of the rust fungus are bottlenecks for molecular investigations. Following the completion of both M. larici-populina and Populus trichocarpa genome sequences, gene families involved in poplar resistance or in rust fungus virulence were investigated, allowing the identification of key genetic determinants likely controlling the outcome of the interaction. Specific expansions of resistance and defense-related genes in poplar indicate probable innovations in perennial species in relation with host-pathogen interactions. The genome of M. Larici-populina contains a strikingly high number of genes encoding small secreted proteins (SSPs) representing hundreds of candidate effectors. Transcriptome analyses of interacting partners in compatible and incompatible interactions revealed conserved set of genes involved in poplar defense reactions as well as timely regulated expression of SSP transcripts during host tissues colonisation. Ongoing functional studies of selected candidate effectors will be achieved mainly on the basis of recombinant protein purification and subsequent characterisation.

Behavior of Yersinia enterocolitica in Foods

Md. Latiful Bari, M. Anwar Hossain, Kenji Isshiki, and Dike Ukuku — Sun, 23 Oct 2011 14:15:36 +0000

Yersinia enterocolitica are ubiquitous, being isolated frequently from soil, water, animals, and a variety of foods. They comprise a biochemically heterogeneous group that can survive and grow at refrigeration temperatures. The ability to propagate at refrigeration temperatures is of considerable significance in food hygiene. Virulent strains of Yersinia invade mammalian cells such as HeLa cells in tissue culture. Two chromosomal genes, inv and ail, were identified for cell invasion of mammalian. The pathogen can cause diarrhoea, appendicitis and post-infection arthritis may occur in a small proportion of cases. The most common transmission route of pathogenic Y. enterocolitica is thought to be fecal-oral via contaminated food. Direct person-to-person contact is rare. Occasionally, pathogenic Y. enterocolitica has been detected in vegetables and environmental water; thus, vegetables and untreated water are also potential sources of human yersiniosis. However, the isolation rates of pathogenic Y. enterocolitica have been low, which may be due to the limited sensitivity of the detection methods. To identify other possible transmission vehicles, different food items should be studied more extensively. Many factors related to the epidemiology of Y. enterocolitica, such as sources, transmission routes, and predominating genotypes remain obscure because of the low sensitivity of detection methods.

Antimicrobial Activity of Copper Alone and in Combination with Lactic Acid against Escherichia coli O157:H7 in Laboratory Medium and on the Surface of Lettuce and Tomatoes

Thu, 20 Oct 2011 14:26:54 +0000

The objective of this study was to evaluate the effect of copper alone and in combination with lactic acid against E. coli O157:H7 in laboratory medium and on the surface of lettuce and tomatoes. Four strains of E. coli O157:H7 were individually inoculated into BHI broth containing different concentrations of copper (5, 10, 20, and 40 ppm, w/v), lactic acid (0.1 and 0.2%, v/v), and their combinations. After incubation, aliquots of 1 mL from each sample were withdrawn and plated on BHI agar to determine the bacterial population. Significant growth inhibition (𝑃<0.05) was observed with a combination treatment of copper (40 ppm) and lactic acid (0.2%). The population of E. coli O157:H7 was reduced by 3.93 and 3.39 log on the surface of lettuce and tomato samples, respectively, when treated with the same combination. This indicates that combination of copper and lactic acid could be used as an effective solution to inhibit E. coli O157:H7 on fresh produce.

Yersinia enterocolitica: Epidemiological Studies and Outbreaks

Sun, 16 Oct 2011 10:54:33 +0000

Yersinia enterocolitica is the most common bacteriological cause of gastrointestinal disease in many developed and developing countries. Although contaminated food is the main source of human infection due to Y. enterocolitica, animal reservoir and contaminated environment are also considered as other possible infection sources for human in epidemiological studies. Molecular based epidemiological studies are found to be more efficient in investigating the occurrence of human pathogenic Y. enterocolitica in natural samples, in addition to conventional culture based studies.

Yersinia enterocolitica and Yersinia pseudotuberculosis Detection in Foods

H. Fukushima, S. Shimizu, and Y. Inatsu — Wed, 05 Oct 2011 16:49:26 +0000

Yersinia enterocolitica and Y. pseudotuberculosis which can cause yersiniosis in humans and animals are thought to be significant food-borne pathogens and be important as hygiene indicator in food safety. The pathogenic Y. enterocolitica serotypes/biotypes are O:3/4 and 3 variant VP negative, O:5, 27/2, O:8/1b, and O:9/2, have been reported worldwide. Y. pseudotuberculosis is distributed less widely than Y. enterocolitica. Isolation methods usually involve selective and recovery enrichment of the food sample followed by plating onto selective media, confirmation of typical colonies and testing for virulence properties of isolated strains. Recently, DNA-based methods, such as PCR assays, have been developed to detect pathogenic Y. enterocolitica and Y. pseudotuberculosis in foods more rapidly, and sensitivity than can be achieved by conventional culture methods. This paper reviews commercially available conventional and PCR-based procedures for the detection of pathogenic Yersinia in food. These methods are effective as the isolation and detection methods to target pathogenic Y. enterocolitica and Y. pseudotuberculosis in foods.