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PubMed2003

Biocontrol of foliar pathogens: mechanisms and application.

Biocontrol offers attractive alternatives or supplements to the use of conventional methods for plant disease management. Vast experience has been gained in the biocontrol of plant diseases. Prevention of infection by biocontrol agents or suppression of disease is based on various modes of action. Pathogens are typically affected by certain modes of actions and not by others according to their nature (i.e. biotrophs vs. necrotrophs). Resistance in the host plant may be induced locally or systemically by either live or dead cells of the biocontrol agent and may affect pathogens of various groups. As some pathogens are negatively affected by lake of nutrients in the infection court, competition for nutrients and space was long recognized as antagonism trait. Antibiosis and hyperparasitism affect pathogens of various groups. Other valid mechanisms are reduction of the saprophytic ability and reducing spore dissemination. Recently it was revealed that restraining of pathogenicity factors of the pathogens, i.e. host hydrolyzing proteins or reactive oxygen species takes place when biocontrol is used. It is likely that several modes of action concomitantly participate in pathogens suppression but the relative importance of each one of them is not clear. Examples of effective prevention of infection in the phyllosphere that rely on multiple modes of action will be demonstrated with Trichodermo harzianum T39 (TRICHODEX), Bacillus mycoides and Pichia guilermondii, a filamentous fungus, bacterium and yeast biocontrol agents, respectively. Several commercial products based on microorganisms have been developed and are starting to penetrate the market. However, large-scale use is still limited because of variability and inconsistency of biocontrol activity. In some cases this may be caused by sensitivity of the biocontrol agents to environmental influences. Ways to overcome biocontrol limitations and to improve its efficacy are i. integration of biocontrol with chemical fungicides on a calendar basis or according to ecological requirements of the biocontrol agents relying on the advise of a decision support system; ii. introduction of two or more biocontrol agents in a mixture, assuming that each one of them has different ecological requirements and/or different modes of action. Implementation of one (or more) of these approaches, using biocontrol preparations mentioned above lowered the variability and increased the consistency of disease suppression. The expected long-term result of the implementation of these suggested strategies is reduced risk of uncontrolled epidemics and increase of confidence of growers in using this non-chemical control measure on a large scale.

Anti-Bacterial Agents↗

PubMed2004

Trends and antimicrobial resistance of pathogens causing bloodstream infections among febrile neutropenic adults with hematological malignancy.

BACKGROUND AND PURPOSE: The microbiological spectrum in cancer patients with febrile neutropenia has changed over the past several decades in western countries. The growing incidence of antimicrobial resistance is an inevitable consequence of the widespread use of antibiotics in medical settings. The aim of this study was to clarify the trends and antimicrobial resistance among pathogens causing bloodstream infections in febrile neutropenic adults with hematological malignancies. METHODS: The characteristics of pathogens causing bloodstream infection isolated from patients with febrile neutropenia who were treated at National Taiwan University Hospital from 1996 to 2001 were reviewed. A total of 1174 pathogens were isolated from 3093 admissions to a hematological ward during this period. Among them, 738 isolates were recovered from patients with febrile neutropenia. RESULTS: The majority (93%) of these neutropenic febrile patients had underlying acute leukemia or lymphoma. Gram-negative bacteria accounted for 57% of isolated pathogens, followed by Gram-positive bacteria (32%), fungi (7%), and anaerobes (3%). In decreasing frequency, Escherichia coli (13%), Klebsiella pneumoniae (12%), Enterobacter cloacae (7%), Pseudomonas aeruginosa (6%), and Acinetobacter baumannii (5%) were the predominant Gram-negative bacteria, while coagulase-negative staphylococci (13%), viridans group streptococci (4%), and Staphylococcus aureus (4%) were the major Gram-positive pathogens. Two-thirds (20/30) of S. aureus isolates were resistant to oxacillin. No vancomycin-resistant enterococci were isolated. Resistance to cefotaxime was found in 63% of E. cloacae, 13% of K. pneumoniae and 10% of E. coli. Overall, 33% of E. coli and 13% of K. pneumoniae were resistant to ciprofloxacin. CONCLUSIONS: This study indicates that the microbiological spectrum of microorganisms causing bloodstream infections in neutropenic febrile patients with hematological malignancies at National Taiwan University Hospital is different from western countries in that Gram-negative bacteria remain the predominant pathogens. Antimicrobial resistance among these pathogens is high and E. coli and K. pneumoniae isolates with resistance to third-generation cephalosporins and ciprofloxacin are increasing.

Adult↗

PubMed1992

Isolation of pathogenic strains of Haemophilus somnus from the female bovine reproductive tract.

The prevalence of Haemophilus somnus in the genital tract of slaughtered and live cows in southern Ontario was investigated. The vagina and uterus of slaughtered cows were swabbed separately. Live cows were examined and sampled in two field surveys: Centre A and Centre B. In the former, aspirated mucus secretions and in the latter, specimens obtained by guarded swabbing were examined bacteriologically. Haemophilus somnus was isolated from 28 genital tracts of 461 slaughtered (6.1%), and seven of 199 live (3.5%) cows during the centre B survey. The isolates were recovered from both normal and diseased reproductive tracts. Fourteen strains isolated from genital organs were examined for pathogenicity in vivo to test the occurrence of pathogenic isolates. In the initial stage of the in vivo study on pathogenicity, each of the fourteen isolates was examined on one calf using an intracisternal inoculation. Subsequently, one pathogenic and one nonpathogenic strain were inoculated into five calves each to statistically confirm their pathogenic potential. Of 14 genital isolates of H. somnus examined in an intracisternal calf assay, six (43%) caused a fatal peracute neurological disease, while eight were nonpathogenic. A comparative pathological study of pathogenic and nonpathogenic isolates showed that the former caused a severe fatal suppurative meningoencephalitis whereas the latter caused no lesions whatsoever or a mild leukocytic leptomeningitis. The salient data obtained in this study indicate that there are pathogenic strains of H. somnus in the genital tract of apparently normal cows as well as of those with inflammatory disease.

Abattoirs↗

PubMed2005

Impact of pathogen burden on in-stent restenosis in patients after coronary stent implantation.

BACKGROUND: Although some certain infectious pathogens could be detected in the patients with coronary artery disease, the roles of these infectious factors in the development of coronary artery diseases remain largely unknown. Since the number of infectious pathogens has been argued to be relative to the coronary artery diseases, we therefore examined whether there is a link between the number of infections and the incidence of in-stent restenosis after stent implantation. METHODS: One hundred and eighty-one patients were enrolled in this study. Infectious pathogens including serum anti-Chlymydia pneumoniae, cytomegalovirus, Helico pylori, human herpes simplex virus-1, human herpes simplex virus-2 antibodies and hepatitis B virus antigen were measured in all patients before coronary stent implantation. Coronary angiography was performed before, immediately after and 6 months after stent implantation. RESULTS: Restenosis rate 6 months post stent implantation was similar in patients with low pathogen burden (< 3 pathogens, 33.3%) to those with high pathogen burden (> or = 3 pathogens, 29.1%). CONCLUSIONS: Previous infections with Chlymydia pneumoniae, cytomegalovirus, Helico pylori, human herpes simplex virus-1, human herpes simplex virus-2 and hepatitis B virus do not contribute to the incidence of restenosis after stent implantation.

Adult↗

PubMed2006

Frequency and susceptibility profile of pathogens causing urinary tract infections at a tertiary care hospital in western Nepal.

INTRODUCTION: Urinary tract infection (UTI) is the most common nosocomial infection among hospitalised patients. Area-specific monitoring studies aimed to gain knowledge about the type of pathogens responsible for UTIs and their resistance patterns may help the clinician to choose the correct empirical treatment. Recent reports have shown increasing resistance to commonly-used antibiotics. We aimed to study the antibiotic resistance pattern of the urinary pathogens isolated from hospitalised patients. METHODS: Three urine samples were collected by the mid-stream "clean catch" method from 1,680 clinically-suspected cases of urinary tract infections from inpatients of various clinical departments during one year. The samples were tested microbiologically by standard procedures. Antibiotic susceptibility of the isolated pathogens was tested for commonly-used antibiotics by Kirby-Bauer technique according to NCCLS guidelines. RESULTS: Significant bacteriuria was present in 71.7 percent of the samples, 17 percent were sterile, 4.8 percent showed insignificant bacteriuria, and 6.5 percent non-pathogenic bacteriuria. The most common pathogens isolated were Escherichia coli (59.4 percent), Klebsiella spp (15.7 percent) and Enterococcus faecalis (8.1 percent). The mean susceptibility was high for amikacin (87.2 percent), ciprofloxacin (74.8 percent), ceftazidime (71.5 percent) and gentamicin (70.4 percent) but low for nitrofurantoin (35 percent), cephalexin (49.7 percent) and ampicillin (50.5 percent). Escherichia coli was found to be most susceptible to amikacin (98 percent) followed by gentamicin (87.9 percent), ceftazidime (80.8 percent), norfloxacin (78.4 percent) and cotrimoxazole (77.9 percent). CONCLUSION: A high isolation rate of pathogens from urine samples of clinically-suspected UTI shows a good correlation between clinical findings and microbiological methods. The antibiotics commonly used in UTIs are less effective. Since the present study was a cross-sectional study, regular monitoring is required to establish reliable information about resistance pattern of urinary pathogens for optimal empirical therapy of patients with nosocomial UTIs.

Adolescent↗

PubMed2006

In silico identification of potential therapeutic targets in the human pathogen Helicobacter pylori.

Availability of genome sequences of pathogens has provided a tremendous amount of information that can be useful in drug target and vaccine target identification. One of the recently adopted strategies is based on a subtractive genomics approach, in which the subtraction dataset between the host and pathogen genome provides information for a set of genes that are likely to be essential to the pathogen but absent in the host. This approach has been used successfully in recent times to identify essential genes in Pseudomonas aeruginosa. We have used the same methodology to analyse the whole genome sequence of the human gastric pathogen Helicobacter pylori. Our analysis revealed that out of the 1590 coding sequences of the pathogen, 40 represent essential genes that have no human homolog. We have further analysed these 40 genes by the protein sequence databases to list some 10 genes whose products are possibly exposed on the pathogen surface. This preliminary work reported here identifies a small subset of the Helicobacter proteome that might be investigated further for identifying potential drug and vaccine targets in this pathogen.

Anti-Bacterial Agents↗

PubMed1990

Characterization of potentially pathogenic free-living amoebae in sewage samples of Calcutta, India.

1. It is widely accepted that foul or polluted environments are the principal sources of potentially pathogenic species of free-living amoebae. The present paper is the first report of occurrence of potentially pathogenic free-living amoebae in sewage samples of Calcutta, India. 2. We describe the occurrence, isolation, specific identification and comparative mouse pathogenicity test of two pathogenic amoebae, viz., Naegleria fowleri (N. aerobia) Carter, 1970, causing human meningoencephalitis and Acanthamoeba castellanii Douglas, 1930, causing granulomatous amoebic encephalitis, and one non-pathogenic amoeba, viz., A. astronyxis Ray and Hayes, 1959, in sewage samples of Calcutta, India. 3. The existence of both pathogenic and non-pathogenic amoebae living side by side is of considerable epidemiological relevance.

Acanthamoeba↗

PubMedDate not supplied

Pathogenicity of avian influenza viruses isolated from wild mallard ducks and domestic turkeys.

Groups of turkeys were exposed to different isolates of avian influenza virus from wild mallard ducks and domestic turkeys by the intracerebral, intravenous, intratracheal, and intra-airsac routes, and pathogenicity indices were calculated. For the intracerebral pathogenicity study, body weight was also measured. For intravenous, intratracheal, and intra-airsac pathogenicity studies, necropsy lesions were scored and serological responses were recorded. Only the intracerebral pathogenicity index and body weight gain post intracerebral infection demonstrated any differences between isolates. The other procedures failed to demonstrate any pathogenicity whatsoever. There was a correlation (R = 0.73) between intracerebral pathogenicity index and reduced weight gain postinfection. These studies suggest that growth suppression may be an objective measure of pathogenic potential of influenza viruses found to be nonpathogenic by other methods.

Animals↗

PubMed1981

Phagocytic and bactericidal activity of human neutrophils against two isolates of Group B streptococci Type Ic of differing pathogenicity.

The phagocytic and bactericidal activities of normal adult human neutrophils against 2 strains of Group B streptococci Type Ic of differing pathogenicity were examined. Both isolates were phagocytosed by the neutrophils in the presence of normal and homologous immune serum. However, the highly pathogenicity streptococci were killed less readily in the presence of immune serum than were the streptococci of low pathogenicity in the presence of immune or normal serum. This difference in killing ability was not due to a defect in phagocytosis by the neutrophils, but to a defect in bactericidal activity. The highly pathogenic streptococci were not killed in the presence of normal serum, but were readily phagocytosed by the neutrophils, in which they accumulated and eventually caused their destruction. The streptococci of low pathogenicity, however, were killed equally as well in the absence of specific antibody as in its presence. It is suggested that an in vitro assessment of neutrophil function against streptococci of differing pathogenicity for mice may provide a useful method by which the pathogenicity of streptococci for man can be compared.

Adult↗

PubMed1995

Molecular mapping of a pathogenically relevant BP180 epitope associated with experimentally induced murine bullous pemphigoid.

Bullous pemphigoid (BP) and herpes gestationis (HG) are subepidermal blistering diseases associated with an autoimmune response directed against BP180, an epidermal hemidesmosomal glycoprotein. The pathogenic relevance of this Ag/Ab system was established by the recent demonstration that IgG Abs reactive with the murine form of BP180 (mBP180) are capable of triggering a subepidermal blistering disease after passive transfer into neonatal BALB/c mice. The aim of the present study was to determine the fine specificity of the pathogenically relevant Abs in this experimental model of BP. Four high titer rabbit-anti-mBP180 antisera were included in this analysis--only two of which exhibited pathogenic activity in the passive transfer model. Immunoblot analysis using a panel of mBP180 deletion mutants revealed that each of the four rabbit sera reacted with at least three distinct sites on the mBP180 ectodomain; however, this technique failed to distinguish between the reactivity patterns of the pathogenic and nonpathogenic sera. An alternative technique, liquid phase immunoadsorption analysis, was used to identify one mBP180 antigenic site, comprising 9 to 12 amino acids and designated mBP1, that was specifically recognized by the two pathogenic sera. Pre-adsorption of pathogenically active IgG preparations with fusion proteins containing the mBP1 antigenic site resulted in complete blocking of immunofluorescence reactivity with the murine basement membrane zone (BMZ) and in complete neutralization of pathogenic activity. Anti-BMZ reactivity displayed by nonpathogenic Abs was not altered or diminished by pre-adsorption with this same mBP180 recombinant protein. These findings should help to elucidate the immunopathologic mechanisms responsible for human BP and HG and may have significant implications in the diagnosis and treatment of these autoimmune diseases.

Animals↗

PubMed1995

Identification of a major pathogenic epitope in the human IRBP molecule recognized by mice of the H-2r haplotype.

PURPOSE: Mice of the H-2b, H-2k, and H-2r haplotypes develop experimental autoimmune uveoretinitis (EAU) after immunization with interphotoreceptor retinoid-binding protein (IRBP) of bovine or monkey origin. The purpose of this study was to identify putative pathogenic epitope(s) of IRBP and to establish their immunodominance within the IRBP molecule. METHODS: Overlapping 20-amino acid peptides, spanning the entire human IRBP molecule, were synthesized and used to immunize C57BL/10 (H-2b), B10.BR (H-2k), and B10.RIII (H-2r) mice. Bovine IRBP was used as a positive control. Experimental autoimmune uveoretinitis was examined by histopathology 21 days after immunization. Immunologic responses were assessed by delayed-type hypersensitivity (DH) and lymphocyte proliferation assays. RESULTS: Peptide 161-180, spanning the sequence SGIPYIISYLHPGNTILHVD, was found to be highly pathogenic for B10.RIII mice but not for the other strains. A dose-response curve showed that peptide 161-180 was maximally pathogenic at 50 micrograms, but incidence and scores were reduced at 10 micrograms. The truncated 13-mer 165-177 was also highly pathogenic (100 to 200 micrograms), suggesting that it contained the pathogenic epitope. Mice immunized with the peptide, or with whole IRBP, had positive DH and lymphocyte responses to the immunizing as well as to the reciprocal antigen. A cell line derived to peptide 161-180 was also pathogenic for B10.RIII mice after adoptive transfer and responded (proliferation) to native IRBP. CONCLUSIONS: High incidence and high severity scores, as well as immunologic cross-recognition of peptide 161-180 and native IRBP in vivo and in vitro, suggest that this peptide contains a major epitope recognized as pathogenic by B10.RIII mice.

Amino Acid Sequence↗

PubMed1993

OSHA's bloodborne pathogens standard: analysis and recommendations.

Just over a year ago, the Occupational Safety and Health Administration (OSHA) issued the final bloodborne pathogens standard, "Occupational Exposure to Bloodborne Pathogens; Final Rule," which requires healthcare institutions to protect their employees from all occupational exposure to bloodborne pathogens." According to OSHA, the only criterion for applying the standard is the likelihood of exposure to blood and other potentially infectious materials (OPIMs). Thus, the standard is designed to protect all vulnerable personnel, from the clinical engineers who service contaminated equipment to the staff in clinical laboratories, patient care or treatment areas, and housekeeping and laundry services--any location where the nature of the work poses the risk of exposure to bloodborne pathogens. All department heads and employees must have access to the standard and should carefully review our analysis of the regulations and recommendations for implementing them, as presented in this special issue of Health Devices. The standard is aimed at protecting employees from occupational exposure to all bloodborne pathogens and, especially, to the human immunodeficiency virus (HIV) and the hepatitis B virus (HBV)--the most infamous pathogens transmitted through occupational exposure to blood and body fluids. Other bloodborne diseases referenced by OSHA in the preamble to the standard include arboviral infections, babesiosis, brucellosis, Creutzfeldt-Jakob disease, hepatitis C, human T-lymphotropic virus type I, leptospirosis, malaria, relapsing fever, syphilis, and viral hemorrhagic fever. In this issue, we provide a clinical overview of HIV and HBV and the diseases they cause, as well as a brief discussion of other bloodborne pathogens; an analysis of the most significant regulations affecting hospitals; and our recommendations for compliance. The recommendations presented in this article do not exhaust the possibilities for reducing exposure and complying with the standard. We invite you to communicate your ideas and practices regarding compliance issues to the ECRI-sponsored Center for Healthcare Environmental Management (CHEM) for possible inclusion in a future update to its loose-leaf reference publication, the Healthcare Environmental Management System. We wish to acknowledge CHEM's contribution in developing this special report, which was reviewed by the Centers for Disease Control and Prevention (CDC), the National Institute for Occupational Safety and Health (NIOSH), and OSHA. Also see "CDC's Recommendations for Hepatitis B Vaccination and Postexposure Follow-up" and "A Minimal Training Syllabus" in this issue.

Blood↗

PubMed1996

Scope of urinary pathogens isolated in the Public Health Bacteriology Laboratory, Harare: antibiotic susceptibility patterns of isolates and incidence of haemolytic bacteria.

OBJECTIVES: To determine the scope of urinary pathogens isolated in the Public Health Bacteriology Laboratory, their antibiotic susceptibility patterns and the incidence of haemolytic bacteria in Harare. DESIGN: Prospective study. Patients of different age groups attending various clinics in Parirenyatwa Hospital, Harare, between October 1995 and April 1996 were enrolled for the study. SETTING: A laboratory based study at the Bacteriology Unit, Public Health Laboratories, Harare. SUBJECTS: 1,760 urine specimens obtained from male and female patients suspected of having UTI. RESULTS: Out of a total number of 1,760 urine specimens screened only 473 (26.9pc) were positive for UTI pathogens. Four hundred and nineteen (88.5pc) and 46 (9.7pc) of the 473 positive UTI pathogens were Gram negative and Gram positive bacteria respectively. Eight (1.7pc) of the positive isolates were Candida spp. The commonest pathogen isolated was Escherichia coli (40.5pc), followed by Klebsiella spp. (22.1pc) and Proteus spp. (7.2pc). Of the positive isolates 184 (38.9pc) and seven (1.5pc) were beta- and alpha-haemolytic respectively. Of E. coli isolates 72pc were beta-haemolytic. Sex distribution showed that 53pc and 47pc of the UTI pathogens were isolated from males and females respectively. E. coli was more predominant in females (51.3pc). Antibiotic susceptibility patterns revealed that 100pc of strains of E. coli, Proteus spp., Serratia spp., Salmonella spp., Morganella spp., Staphylococcus aureus and coagulase negative staphylococci (CNS) were sensitive to Ciprofloxacin. Urinary isolates were markedly resistant to Tetracycline, Carbenicillin, Cotrimoxazole, Ampicillin and Nitrofurantoin. Fusidic acid and Clindamycin were active against staphylococcal species. CONCLUSION: We conclude that E. coli is the commonest UTI pathogen and that 72pc of strains were beta-haemolytic. We suggest the use of Ciprofloxacin as the drug of choice for the treatment of UTI caused by both Gram positive and Gram negative UTI pathogens. Nitrofurantoin and Gentamycin are in addition recommended for E. coli while Fusidic acid and Clindamycin may be useful for staphylococcal species.

Adolescent↗

PubMed2026

Genomic characterization and pathogenicity of ruminant Listeria monocytogenes isolates in a murine oral infection model.

Listeria monocytogenes is a major foodborne pathogen; its ruminant isolates display zoonotic characteristics, causing similar clinical signs in humans, including abortion and encephalitis. However, data on whole genome sequencing and pathogenicity of ruminant L. monocytogenes isolates remain sparse. This study aimed to analyze the genotypic characteristics of L. monocytogenes isolates from ruminants with listeriosis. Furthermore, we assessed the in vivo pathogenicity of four ruminant L. monocytogenes isolates, characterized via whole-genome sequencing-based genetic clustering, in orogastrically inoculated mice. The isolate LM18 (serotype 1/2b, ST224, SL6178) had the lowest lethal dose compared to the other three isolates including previous hypervirulence type (serotype 4b, ST1, SL1) and caused secondary bacteremia in lungs, with sustained bacterial loads in the spleen and liver. Genomic (listeria pathogenicity island -1 and -3) and virulence gene (actA and llsX) mutation analyses associated with virulence suggested from well-recognized studies could not elucidate the virulence of the isolates. SSI-1, which only exists in the isolate LM18 (serotype 1/2b, ST224, SL6178), may help L. monocytogenes survive in the gastrointestinal environment, thereby affecting its virulence. Further research should investigate the role of SSI-1 in the pathogenicity of L. monocytogenes. Moreover, additional studies utilizing larger datasets of ruminant isolates are required to validate our genotypic characterization and to obtain a comprehensive picture of further genotypic differences crucial for L. monocytogenes pathogenicity.

Animals↗

PubMed2002

Antibody reactivity of a standardized human serum protein solution against a spectrum of microbial pathogens and toxins: comparison with fresh frozen plasma.

In this study, we compared a standardized solution of human serum protein (HSP) and fresh frozen plasma (FFP) with regard to the antibody specificity against a number of microbial pathogens and some important pathogenicity factors of bacterial pathogens. Due to the clinical use of HSP and FFP for therapeutical plasma exchange, we have chosen a spectrum of microbial pathogens for serological analysis that is critical in clinical settings. With the enzyme-linked immunosorbent assay technique, we could show that HSP contains marked IgG antibody reactivity against antigens of Escherichia coli, Campylobacter jejuni, Enterobacter sakazakii, Proteus mirabilis, Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus aureus, S. epidermidis, Streptococcus pneumoniae, Enterococcus faecalis, Chlamydia pneumoniae, and Candida albicans. Although no IgM antibodies against the pathogens tested could be detected in HSP, moderate IgA reactivity was found against 4 of 12 microbial antigens. Immunoblot analysis demonstrated specific IgA and IgG responses against the endoproteinase Glu-C and the superantigens enterotoxin A and B of S. aureus, the IgA-protease of Neisseria gonorrhoeae, and Shiga toxin 2 of enterohemorrhagic E. coli. By using 3 different HSP batches in parallel, we could demonstrate antibody reactivity against important microbial pathogens and toxins. This antibody profile is essentially more homogeneous than that of 3 batches of FFP.

Antibody Specificity↗

PubMed2026

Pathogen Species-Specific Differences in Induction of the Maize Polyubiquitin Gene Promoter in Transgenic Wheat.

The maize polyubiquitin promoter (ZmUbi) is a mainstay in molecular biology for transgene expression and is used for constitutive expression of defense-related gene products. Transgenic wheat lines were produced expressing a ZmUbi-RUBY reporter gene that produces the red pigment betalain. Some lines showed transgene silencing with reduced RUBY transcript accumulation and chimeric sectors of betalain. Infection of these plants with Blumeria graminis, Puccinia graminis f. sp. tritici (Pgt), or P. triticina (Pt) each resulted in localized betalain accumulation at infection sites and increased RUBY transcript accumulation. In contrast, two isolates of P. striiformis f. sp. tritici (Pst) caused no detectable RUBY transcript accumulation and no visible betalain accumulation at infection sites, although a modest betalain increase was detected in infected tissue extracts. Compared with Pst, Pgt more strongly induced host genes involved in transcriptional and post-transcriptional regulatory processes, although no obvious pathogen-induced changes in ZmUbi promoter methylation were observed. ZmUbi-GUS transgenic wheat plants were also pathogen challenged, and, unlike Pst, both Pgt and Pt induced localized GUS staining at infection sites. Database mining showed that the endogenous maize polyubiquitin gene from which ZmUbi is derived was pathogen inducible, albeit in a species-specific fashion. These pathogen differences in ZmUbi induction have implications when using this regulatory element to express defense-related transgenes in wheat. Comparing the resistance efficacy of transgenes against different pathogens using this promoter is potentially influenced by significant, localized expression differences occurring at infection sites of different pathogen species. [Formula: see text] Copyright © 2026 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Promoter Regions, Genetic↗

PubMed2026

Genetic Diversity and Pathogenicity of Thielaviopsis paradoxa Isolates and Implications for Coconut Palm Disease Management.

Thielaviopsis paradoxa is an important soilborne pathogen causing bleeding disease and stem rot of coconut and other palm species, posing a serious threat to coconut production in Hainan Province, China. This study investigated the biological characteristics, pathogenic variability, and genetic diversity of T. paradoxa isolates collected from coconut palms in this region, where population-level data remain limited. Isolates exhibited variability in mycelial growth and sporulation under different temperature, pH, and nutrient conditions, indicating physiological differentiation among strains. Pathogenicity assays across multiple coconut varieties revealed four pathogenicity types, with some isolates consistently showing greater aggressiveness. Genetic analysis based on ISSR markers revealed a high level of genetic diversity (82.96% polymorphism). Genetic clustering showed partial associations with geographic origin, host source, and pathogenicity patterns; however, these relationships are correlative and do not imply causality. Overall, this study provides the first region-specific synthesis of physiological traits, pathogenic variability, and ISSR-based genetic diversity of T. paradoxa in Hainan, contributing baseline information for future population genomic studies and supporting the development of improved disease management strategies for coconut palms.[Formula: see text] Copyright © 2026 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.

China↗

PubMed2026

Molecular surveillance of foodborne bacterial pathogens and resistome in food products from Hong Kong.

Foodborne infections pose an increasing public health challenge worldwide. The problem has been aggravated by the dissemination of antimicrobial resistance genes among zoonotic pathogens, which results in a sharp increase in antibiotic resistance rate recorded among the major foodborne pathogens. To obtain an overview of the extent to which food products purchased in the markets in Hong Kong were contaminated by foodborne pathogens, we collected 95 raw meat samples from wet markets and isolated 236 bacterial strains of various species, with Escherichia coli being the most dominant species (131 strains). Contamination of food products by multiple foodborne pathogens was commonly observed. These include both Gram-positive and Gram-negative bacteria that exhibit various levels of resistance, with some possessing multiple clinically important antibiotic resistance genes. Seventeen bacterial strains of various species isolated from three food samples were comprehensively analysed by the Oxford Nanopore R10.4 technology. Novel conjugative plasmids carrying antimicrobial resistance gene-bearing mobile genetic elements were commonly detectable in the test strains. Some of the plasmids were shown to have originated from other environmental sources or other bacterial species, indicating that raw foods in the local market may serve as a reservoir of resistance-encoding genetic elements from which such elements are disseminated to various microbial pathogens. These findings suggest a need to perform periodic but comprehensive surveillance of multidrug-resistant bacterial pathogens and the major antimicrobial resistance genes in common food products, so as to disrupt the transmission routes of such organisms and the resistance-encoding genetic elements that they harbour.

Hong Kong↗