Virulence Properties Research Articles

Microbiological Investigation and Virulence Factor Characterization of Chronic Suppurative Otitis Media in A Nigerian Tertiary Hospital

Background: Chronic suppurative otitis media (CSOM) is a common cause of hearing loss with the attendant poor academic performance and low productivity in workplaces. Objectives: This study investigated the microbial aetiology and associated virulence mechanisms of CSOM in a Nigerian tertiary hospital. Methods: This was a prospective study of 52 patients diagnosed with CSOM in either one or both ears who had not taken any antibiotics for at least the last seven (7) days. Ear swabs were taken by an otolaryngologist and sent to the Microbiology Department for processing. The specimens were cultured within 30 min of collection and the isolates identified using standard microbiological techniques. Selected virulence properties were characterised. Results: The most common organism isolated was Staphylococcus aureus 18 (34.6%) followed by Pseudomonas aeruginosa 14 (26.9%). Fungal isolates were recovered from 6 11.5%) of specimens; in 11 (21.15%) of cases no microbe was detected. Age did not significantly affect incidence of CSOM of microbial origin (p = 0.1742) although most cases were in the age 31-40 years group. Male and female patients were almost equally affected (M: F = 1:1.08), DNase followed by biofilm formation were the predominant virulence phenotypes identified while coagulase, followed by haemolysin production, were least common. Conclusion: Staphylococcus aureus and Pseudomonas aeruginosa were the most common organisms among CSOM cases and recovered from all age-groups. Early detection and infection control are key to reducing incidence of CSOM.

Monitoring the genetic variation of some Escherichia coli strains in wild birds and cattle.

To date, there is limited data about the genetic relationship ofEscherichia colibetween wild birds and cattle because these birds act as silent vectors for many zoonotic bacteria. This study aimed to elucidate the role of rooming wild birds in the vicinity of cattle farm in transmission of the same pathogenicE. colivariants, identifying their virulence, resistance traits and genetic similarities offimH virulence gene. About 240 faecal/cloacal swabs were collected from both species and examined bacteriologically.Escherichia coliwas yielded in 45.8% and 32.5%, respectively, of examined cattle and wild birds. The most prevalent detectedE. coliserovar was O26. High tetracycline and chloramphenicol resistance were recorded; however, gentamycin and ciprofloxacin exhibited the highest sensitivity rates. Polymerase chain reaction (PCR) conserved genotypic resistance (tetA andblaCTX-M) and virulence attributes (fimH,stx1,eaeA andompA) ofE. coliisolates were discussed in detail. ThefimH gene revealed 100% sequence similarity when comparing with differentE. coliisolates globally and locally. Finally, a close genetic association ofE. coliwith both wild birds and cattle was detected, thus strengthening its role in the dissemination of the infection via environment. Prevention and conservative policy should be carried asE. coliconstitute enormous significant zoonotic risks to livestock and animal workers. Also, further studies to the whole genome sequencing offimH, other virulence and resistance genes ofE. coliare recommended trying to limit the possibilities of co-infection and transfer among different species.Contribution:The current study recorded updated data about the critical infectious role of wild birds to livestock, including cattle farms in Egypt. It also delivered some recommendations for good hygienic practices in cattle farms which must be implemented for handling animal manure.

Risk Factors and Associated Outcomes of Virulence Genes eae, entB, and pipD Carriage in Escherichia coli, Klebsiella pneumoniae, and Salmonella spp. From HIV-1 and HIV-Negative Gastroenteritis Patients in the Dschang Regional Hospital Annex.

Background Enterobacteriaceae is one of the main families of gram-negative bacilli responsible for serious infections in humans. The severity of infection by these bacteria is a product of many factors, including virulence properties and antimicrobial resistance. This severity may be further intensified if there is an association between these factors and a depressed immune system, such as in HIV patients. This study aimed to determine the distribution of representative virulence genes among key Enterobacteriaceae isolates from HIV-1 and non-HIV gastroenteritis patients and the relationship between carrying these virulence genes and antimicrobial susceptibility, seropositive status, and severity of symptoms associated with Enterobacteriaceae infections in Dschang Regional Hospital Annex. Methodology A total of 200 gastroenteritis patients (100 HIV-1 and 100 non-HIV patients) were selected and evaluated forsymptoms associated with gastroenteritis. Stool samples were obtained and cultured, from which Escherichia coli, Klebsiella pneumoniae, and Salmonella spp. isolates were obtained. Antibiotic susceptibility tests were performed on the isolates by agar disc diffusion using commonly used antibiotics. These isolates were tested for the possession of virulence genes by polymerase chain reaction (PCR); eae for E. coli, entB for K. pneumoniae, and pipD for Salmonella spp. Correlation tests and risk assessments were performed between the presence of virulence genes, antibiotic resistance, and specific symptoms. Results Theisolates obtained from HIV-positive and HIV-negative patients were, respectively, 61 against 62 for E. coli, 10 against 21 for K. pneumoniae, and 11 against 15 for Salmonella spp.These organisms showed the highest resistance to amoxicillin and clavulanic acid, while the least resistance was observed against ofloxacin, gentamicin, and amikacin in both groups of patients. The virulence genes showed a generally higher occurrence in isolates from HIV-negative patients than HIV-positive patients, with the eae gene 5/61 (8.20%) against 12/62 (19.35%), the entB gene4/10 (40.00%) against 14/21 (66.66%), and the pipD gene 5/11 (45.45%) against 7/15 (46.46%) in HIV-positive and negative patients, respectively. There was a significant correlation between eae gene carriage and resistance against imipenem (p = 0.047), gentamycin (p = 0.047), and doxycycline (p = 0.029); entB gene carriage and resistance toward levofloxacin (p = 0.017) in K. pneumoniae; and pipD gene carriage and resistance against levofloxacin (p = 0.039), imipenem (p = 0.041), and doxycycline (p = 0.042). The carriage of the virulence genes was seen to be a stronger risk only for the resistance of K. pneumoniae to ceftriaxone (odds ratio (OR) = 2.286) and gentamycin (OR = 3.000), and Salmonella spp. against imipenem (OR = 2.750) and doxycycline (OR = 2.118). The development of severe symptoms correlated significantly with virulence gene carriage in isolates, mainly in HIV-positive patients with eae (p = 0.017) and pipD (p = 0.025), with a strong risk association with the pipD gene (OR = 2.665). Conclusions Antibiotic resistance was associated with virulence gene carriage, indicating that virulence and antibiotic resistance can associate their effects and contribute to poor outcomes in the treatment of bacterial diseases in HIV patients. The possession of virulence genes increased the severity of symptoms associated with gastroenteritis in HIV-positive patients.

ISOLATION AND CHARACTERIZATION OF FUNGI ASSOCIATED WITH BODY AND EGG FROM DISEASED AFRICAN CATFISH, Clarias gariepinus

African catfish (Clarias gariepinus) are in high demand in the Malaysian market. However, these species are known to be easily infected with diseases such as fungi, which can cause mortality and economic losses. In addition, fungal infection in fish eggs can reduce their production. The objective of this study was to isolate and identify fungi from infected African catfish and their eggs. Symptoms include a swollen lesion, irregular swimming, darker discoloration, and screening of pathogenic fungi. Isolations, identifications, and extracellular enzymatic assays were performed for the isolated fungi. Potato dextrose agar was used as isolation medium for isolating fungi on African catfish and their eggs. Fungi were identified by macroscopic observation of growth morphology and their structure, followed by microscopic observation after staining with lactophenol cotton blue to observe hyphae. From the result, three fungi were isolated and identified as Mucor sp. (2n) and Trichoderma sp. (1n). All isolated fungi were also analyzed for extracellular enzymes such as proteases, amylases, and lipases to test their ability to produce them as pathogenic fungi. Trichoderma sp. showed positive results in all tests. However, one strain of Mucor sp. reacted positively to the amylase and lipase test, while the other strain of the same species showed no reaction, indicating a negative result. In conclusion, the isolated fungi have virulent properties and can cause mortality if the body and eggs are infected. Therefore, fish farms need comprehensive health management to prevent the spread of fungal diseases

Clinically significant and colonizing <em>Enterobacteria</em> isolates with extended spectrum beta-lactamase production and their significance in horse breeding

This review article is devoted to the problem of the emergence and spread of antibiotic-resistant enterobacteria producing beta-lactamase in horse breeding. Foal colibacillosis is an acute infectious disease of young animals, manifested by diarrhea, signs of severe intoxication and dehydration of the body, caused by pathogenic Escherichia coli. Foals get sick in the first 3-7 days after birth. Infection occurs alimentary, less often – aerogenic and intrauterine transmission. The source of infection are sick and recovered animals. The duration of the disease is 2-3 days with a mortality rate of up to 90%, which leads to multiple economic losses. Multiresistant Escherichia coli can accumulate in the intestines of healthy animals and be excreted with fecal matter into the environment, which leads to the spread of pathogenic microflora among livestock. In this case, the animals are latent or hidden carriers that do not show clinical signs of the disease. Clinically significant isolates are causative agents of infectious and inflammatory diseases. These microorganisms represent a potential hazard for the development of an infectious process, they exhibit virulent properties that lead to damage to the tissues of the host organism, which significantly limits the possibility of their eradication. Along with clinically significant isolates, there are colonizing isolates that do not cause infection at a specific site. It should be noted that under certain conditions, the colonizing isolate can cause an infectious process. Irrational use of antimicrobials is a key reason for the development of tolerance. Also, the untimely detection of enzyme inactivation of antibiotics by laboratory methods and the spread of resistance genes play an important role. Currently, disks and media with antibacterial drugs are widely used to detect multidrug resistance of microorganisms. Along with these methods, PCR diagnostics and sequencing are used to accurately determine antibiotic resistance genes. Due to the importance and relevance of this topic, many scientists are conducting research to detect and study the multiresistance of enterobacteria such as E. coli, and their spread among animals.

A Novel Robust Method Mimicking Human Substratum To Dissect the Heterogeneity of Candida auris Biofilm Formation.

Candida auris is a pathogen of urgent threat level as marked by the CDC. The formation of biofilms is an essential property of this fungus to establish infection and escape drug treatment. However, our understanding of pathogenesis through biofilm is hampered by heterogeneity in C. auris biofilms observed in different studies. It is imperative to replicate in vivo conditions for studying C. auris biofilm formation in vitro. Different methods are standardized, but the surface used to form biofilms lacks consistency as well as the architecture of a typical biofilm. Here, we report an in vitro technique to grow C. auris biofilms on gelatin-coated coverslips. Interestingly, C. auris cells grown on gelatin-coated coverslips either on modified synthetic sweat media or RPMI 1640 resulted in similar multilayer biofilm formation with extracellular polymeric substances (EPS). This method is also consistent with the biofilm formation of other Candida species, such as Candida glabrata and Candida albicans. Biofilms of C. glabrata developed through this method show pseudohyphae and EPS. This method can be used to understand the molecular basis of biofilm formation, associated pathogenesis, and drug tolerance. The technique is cost-effective and would thus serve in rightful screening and repurposing drug libraries for designing new therapeutics against the less-studied high-alarm pathogen C. auris. IMPORTANCE Heterogeneity is seen when multidrug-resistant C. auris biofilm is cultured using different reported methods. Biofilm formed on the gelatin surface mimics the condition of a host environment that has multilayers and EPS. This method has feasibility for drug screening and analyzing biofilms through three-dimensional (3D) reconstruction. This in vitro biofilm formation technique is also exploited to study the formation of biofilm of other Candida species. The biofilms of C. glabrata and C. albicans can also be correctly mimicked using gelatin in the biofilm-forming environment. Thus, the novel in vitro method for biofilm formation reported here can be widely used to understand the mechanism of biofilm formation, related virulence properties, and drug tolerance of C. auris and other Candida species. This simple and low-cost technique is highly suitable for screening novel inhibitors and repurposed libraries and to design new therapeutics against Candida species.

Occurrence and Patterns of Enterotoxin Genes, spa Types and Antimicrobial Resistance Patterns in Staphylococcus aureus in Food and Food Contact Surfaces in Singapore.

Staphylococcus aureus contamination of food and food contact surfaces is a public health concern given its virulent and antimicrobial-resistant properties worldwide. In this study, a total of 181 MSSA isolates were analyzed for SE genes, antimicrobial resistance patterns, and spa types. Overall, 24.9% of isolates were positive for SE gene detection, with sea being the most prevalent classical SE (18.8%). The most predominant sample sources for SE gene contamination were hand swabs for sea (6/48), meat dishes for seb (3/14) and seafood dishes for sec (2/24). Antimicrobial resistance was also observed at relatively high frequencies for the clinically important antibiotics penicillin G and ampicillin (both 54.7%), followed by tetracycline (14.9%) and azithromycin (8.8%). In addition, characterization of spa types revealed spa type t5078 to be the most predominant (40.3%), with significant associations between spa types t127 and t5521 and the sea gene. This study offers insights into the enterotoxin gene and antimicrobial resistance profiles of S. aureus in cooked or ready-to-eat food to inform future surveillance and epidemiological studies.

Phenotypic determination of virulence attributes of S. aureus and P. aeruginosa isolated from clinical specimens in Port Harcourt, Rivers State

Phenotypic determination of virulence attributes of S. aureus and P. aeruginosa isolated from clinical specimens in Port Harcourt, Rivers State

Characterization of some virulence properties of subclinical mastitis-associated Escherichia coli in Egyptian cows and buffalos.

Characterization of some virulence properties of subclinical mastitis-associated Escherichia coli in Egyptian cows and buffalos.

Antimicrobial Resistance, Virulence Properties and Genetic Diversity of Salmonella Typhimurium Recovered from Domestic and Imported Seafood.

The quantity of seafood imported and produced by domestic aquaculture farming has increased. Recently, it has been reported that multidrug-resistant (MDR) Salmonella Typhimurium may be associated with seafood. However, information is limited to the antimicrobial resistance, virulence properties, and genetic diversity of S. Typhimurium recovered from imported and domestic seafood. This study investigated the antimicrobial resistance, virulence properties, and genetic diversity of S. Typhimurium isolated from domestic and imported catfish, shrimp, and tilapia. A total of 127 isolates were tested for the presence of multidrug-resistance (MDR), virulence genes (invA, pagC, spvC, spvR), and genetic diversity using the Sensititre micro-broth dilution method, PCR, and pulsed-field gel electrophoresis (PFGE), respectively. All isolates were uniformly susceptible to six (amoxicillin/clavulanic acid, ceftiofur, ceftriaxone, imipenem, nitrofurantoin, and trimethoprim/sulfamethoxazole) of the 17 tested antimicrobials and genetically diverse. Fifty-three percent of the Salmonella isolates were resistant to at least one antimicrobial and 49% were multidrug resistant. Ninety-five percent of the isolates possessed the invA gene, 67% pagC, and 43% for both spvC, and spvR. The results suggest that S. Typhimurium recovered from seafood is frequently MDR, virulent, and have the ability to cause salmonellosis.

Virulence of Shigatoxigenic and Enteropathogenic Escherichia coli O80:H2 in Galleria mellonella Larvae: Comparison of the Roles of the pS88 Plasmids and STX2d Phage.

The invasiveness properties of Shigatoxigenic and enteropathogenic Escherichia coli (STEC and EPEC) O80:H2 in humans and calves are encoded by genes located on a pS88-like ColV conjugative plasmid. The main objectives of this study in larvae of the Galleria mellonella moth were therefore to compare the virulence of eight bovine STEC and EPEC O80:H2, of two E. coli pS88 plasmid transconjugant and STX2d phage transductant K12 DH10B, of four E. coli O80:non-H2, and of the laboratory E. coli K12 DH10B strains. Thirty larvae per strain were inoculated in the last proleg with 10 μL of tenfold dilutions of each bacterial culture corresponding to 10 to 106 colony-forming units (CFUs). The larvae were kept at 37 °C and their mortality rate was followed daily for four days. The main results were that: (i) not only the STEC and EPEC O80:H2, but also different E. coli O80:non-H2 were lethal for the larvae at high concentrations (from 104 to 106 CFU) with some variation according to the strain; (ii) the Stx2d toxin and partially the pS88 plasmid were responsible for the lethality caused by the E. coli O80:H2; (iii) the virulence factors of E. coli O80:non-H2 were not identified. The general conclusions are that, although the Galleria mellonella larvae represent a useful first-line model to study the virulence of bacterial pathogens, they are more limited in identifying their actual virulence properties.

Microbiological evaluation of probiotic therapy in patients with pulmonary tuberculosis

Patients with pulmonary tuberculosis and multiple pathogen resistance (MDR) develop persistent disorders of the intestinal microbiome during prolonged multicomponent chemotherapy requiring correction. However, there is limited data on the use of bacterial drugs in patients with tuberculosis followed by assessing their effectiveness. The aim of the study was to evaluate changes in the intestinal microbiome after a course of probiotics along with anti-tuberculosis chemotherapy in patients with MDR tuberculosis.
 Materials and methods. The design a prospective small-cohort study (n = 30). Patients with pulmonary tuberculosis received anti-tuberculosis drugs according to the IV or V regimen, the median of the doses taken was 34.5 (30; 57.5); gastrointestinal syndrome was recorded in all study subjects. Probiotic therapy was applied by using a preparation containing Bifidobacterium bifidum and B. animalis and Lactobacillus casei, L. plantarum, L. delbrueckii subsp.bulgaricus, L. acidophilus. The course of therapy comprised 21 days,1 capsule twice a day. Before and 7 days after probiotics therapy, studies on composition of the intestinal microbiota were carried out, the frequency of virulence factors Enterococcus spp., Staphylococcus spp., Candida spp. was examined; fatty acid composition and activity of enterococcal organic acid production were studied.
 Results. After a course of probiotics, a significant increase in lactobacillus titers was recorded from 5.2 (4.0; 6.0) to 6.1 (6.0; 8.0) lg CFU/g (p = 0.05). The frequency of mucosal colonization by Candida fungi and lactose-negative Escherichia decreased by 2-fold (p = 0.001) and 3-fold (p = 0.05), respectively. The frequency of detected virulent strains significantly decreased: hemolysin-producing staphylococci by 9 times (p = 0.009), enterococci with gelatinase activity by 6 times. E. faecalis membrane oleic acid level significantly increased (C9-C18:1) (p = 0.03). In E. faecium, cis-7-palmitoleic acid (C7-C16:1) and oleic (C9-C18:1) fatty acid level increased by 2-fold (p = 0.05), and for linoleic acid (C18:2) by 4 time (p = 0.04) accompanied by elevated acid formation by 1.5 times.
 Conclusion. A single course of probiotic therapy in patients with pulmonary tuberculosis leads to qualitative microbiome changes, which are characterized by decreased levels of conditionally pathogenic microorganisms with virulent properties and altered composition of the enterococcal cell membrane accompanied by their increased biochemical activity.

Antimicrobial and Anti-Infective Activity of Natural Products—Gaining Knowledge from Novel Studies

Despite advances in the development of antimicrobial drugs in the last centuries, antimicrobial resistance has consistently raised in the last decades, compromising their effectiveness. Novel antimicrobial compounds, especially from natural sources, including plants, microorganisms, and animals, have since become a growing area of research. In this context, studies covering the investigation of their ability to combat resistant microorganisms, either by neutralization or inactivation of pathogen resistance mechanisms and virulence properties, have gained attention. Herein, a collection of 19 manuscripts focused on the antimicrobial and anti-infective activity of natural products, including their mechanisms of action, in silico evidence of antimicrobial activity, synergistic associations with antibiotics, and other aspects, will be discussed.

The Antibiofilm Effects of Antimony Tin Oxide Nanoparticles against Polymicrobial Biofilms of Uropathogenic Escherichia coli and Staphylococcus aureus.

Biofilms are responsible for persistent or recurring microbial infections. Polymicrobial biofilms are prevalent in environmental and medical niches. Dual-species biofilms formed by Gram-negative uropathogenic Escherichia coli (UPEC) and Gram-positive Staphylococcus aureus are commonly found in urinary tract infection sites. Metal oxide nanoparticles (NPs) are widely studied for their antimicrobial and antibiofilm properties. We hypothesized that antimony-doped tin (IV) oxide (ATO) NPs, which contain a combination of antimony (Sb) and tin (Sn) oxides, are good antimicrobial candidates due to their large surface area. Thus, we investigated the antibiofilm and antivirulence properties of ATO NPs against single- and dual-species biofilms formed by UPEC and S. aureus. ATO NPs at 1 mg/mL significantly inhibited biofilm formation by UPEC, S. aureus, and dual-species biofilms and reduced their main virulence attributes, such as the cell surface hydrophobicity of UPEC and hemolysis of S. aureus and dual-species biofilms. Gene expression studies showed ATO NPs downregulated the hla gene in S. aureus, which is essential for hemolysin production and biofilm formation. Furthermore, toxicity assays with seed germination and Caenorhabditis elegans models confirmed the non-toxic nature of ATO NPs. These results suggest that ATO nanoparticles and their composites could be used to control persistent UPEC and S. aureus infections.

An in vitro study on comparative adherence of oral Candida albicans and non–albicans Candida to human buccal epithelial cells and its antifungal susceptibility pattern

Background: Candida spp. are intra-oral commensals in 40-60% of human subjects and the precise factors involved in the development of Candidiasis are still not clear. The adherence of Candida to epithelial cells is one of the main pathogenic characteristics of the genus. Studies have shown that there are variations in the adherence capabilities of different Candida spp., which may explain why some species colonize mucosal surfaces more frequently than others. The aim of this study was to estimate the adherence properties of Candida spp. to buccal epithelial cells and to determine the antifungal susceptibility. Methods: 87 isolates of Candida spp. from known non-diabetic patients with oral Candidiasis were collected from diagnostic microbiology laboratories in central Kerala. The method of Kimura and Pearsall et al was followed with minor modifications to test the adherence. Results: All the three species exhibited adherence with varying capacity. C. albicans was significantly more adherent to buccal epithelial cells than C. tropicalis and C. krusei. Resistance was not observed among the isolates against fluconazole, voriconazole and clotrimazole. Conclusions: In conclusion Candida spp. isolated from oral candidiasis patients exhibited a higher adherence capacity to normal human buccal epithelial cells considered an essential virulence property. As anticipated C. albicans displayed higher virulence activity than non-Candida albicans species.

7-Ethoxycoumarin rescued Caenorhabditis elegans from infection of COPD derived clinical isolate Pseudomonas aeruginosa through virulence and biofilm inhibition via targeting Rhl and Pqs quorum sensing systems

Pseudomonas aeruginosa is an ambidextrous Gram-negative contagium with density convoluted network defined quorum sensing, which enables the persistent survival within the host environment, contributing to various lung related diseases including Chronic Obstructive Pulmonary Disease (COPD). It is clear that P. aeruginosa is a powerful, exquisite pathogen that has adopted a variety of virulence properties through quorum sensing (QS) regulated phenomenon and that it dominates both in the development and exacerbations of COPD. Interestingly, 7-Ethoxycoumarin (7-EC), a compound that adequately mimics QS signaling molecule of P. aeruginosa, was introduced as part of the process of developing novel ways to treat the severe exacerbations. The results showed that, introduction of 7-EC significantly decreased exopolysaccharide-mediated biofilm development of strains isolated from COPD sputum, as evidenced by SEM analysis. Furthermore, 7-EC was able to modulate a variety of virulence factors and motility without subjecting planktonic cells to any selection pressure. Bacterial invasion assay revealed the potential activity of the 7-EC in preventing the active entry to A549 cells without causing any damage to the cells and found functionally active in protecting the C. elegans from P. aeruginosa infection and being non-toxic to the worms. Docking analysis was further proved that 7-EC to be the potential anti-QS compound competing specifically with Rhl and Pqs Systems. Therefore, 7-EC in the utilisation against the P. aeruginosa based infections, may open an avenue for the futuristic mechanistic study in chronic respiratory diseases and a initiator for the development of non-antibiotic based antibacterial therapy.

A C. albicans TRAPP Complex-Associated Gene Contributes to Cell Wall Integrity, Hyphal and Biofilm Formation, and Tissue Invasion.

While endocytic and secretory pathways are well-studied cellular processes in the model yeast Saccharomyces cerevisiae, they remain understudied in the opportunistic fungal pathogen Candida albicans. We previously found that null mutants of C. albicans homologs of the S. cerevisiae early endocytosis genes ENT2 and END3 not only exhibited delayed endocytosis but also had defects in cell wall integrity, filamentation, biofilm formation, extracellular protease activity, and tissue invasion in an in vitro model. In this study, we focused on a potential C. albicans homolog to S. cerevisiae TCA17, which was discovered in our whole-genome bioinformatics approach aimed at identifying genes involved in endocytosis. In S. cerevisiae, TCA17 encodes a transport protein particle (TRAPP) complex-associated protein. Using a reverse genetics approach with CRISPR-Cas9-mediated gene deletion, we analyzed the function of the TCA17 homolog in C. albicans. Although the C. albicans tca17Δ/Δ null mutant did not have defects in endocytosis, it displayed an enlarged cell and vacuole morphology, impaired filamentation, and reduced biofilm formation. Moreover, the mutant exhibited altered sensitivity to cell wall stressors and antifungal agents. When assayed using an in vitro keratinocyte infection model, virulence properties were also diminished. Our findings indicate that C. albicans TCA17 may be involved in secretion-related vesicle transport and plays a role in cell wall and vacuolar integrity, hyphal and biofilm formation, and virulence. IMPORTANCE The fungal pathogen Candida albicans causes serious opportunistic infections in immunocompromised patients and has become a major cause of hospital-acquired bloodstream infections, catheter-associated infections, and invasive disease. However, due to a limited understanding of Candida molecular pathogenesis, clinical approaches for the prevention, diagnosis, and treatment of invasive candidiasis need significant improvement. In this study, we focus on identifying and characterizing a gene potentially involved in the C. albicans secretory pathway, as intracellular transport is critical for C. albicans virulence. We specifically investigated the role of this gene in filamentation, biofilm formation, and tissue invasion. Ultimately, these findings advance our current understanding of C. albicans biology and may have implications for the diagnosis and treatment of candidiasis.

The chaperone ClpC participates in sporulation, motility, biofilm, and toxin production of Clostridioides difficile

In this study, we analyzed the role of ClpC chaperone-protease of C. difficile in virulence-related traits by comparing the phenotypes of a wild-type and a mutant strain lacking the clpC gene (ΔclpC). We performed biofilm, motility, spore formation, and cytotoxicity assays. Our results show significant differences between the wild-type and ΔclpC strains in all analyzed parameters. Based on these findings, we conclude that clpC plays a role in the virulence properties of C. difficile.

VIRULENCE OF PSEUDOMONAS SYRINGAE STRAINS FROM SORIZ (SORGHUM ORYSOIDUM) AND THEIR SPECIALIZATION

Objective. To study the virulence properties of Pseudomonas syringae strains isolated from soriz and various representatives of sorghum crops in Ukraine and to establish the sensitivity range of plants to these pathogens. Methods. Ten strains freshly isolated from soriz (Sorghum orysoidum) were used to study virulence properties, namely: Pseudomonas syringae 210342, 211141a, 211141, 210341, 21034, 210541b, 210541, and Pseudomonas sp. 210521, 21052, 21054, pathogenic strains of sorghum crops from the collection of the Department of Phytopathogenic Bacteria of D. K. Zabolotny Institute of Microbiology and Virology of the National Academy of Sciences of Ukraine and collection strains of phytopathogens that can be potential causative agents of bacterial diseases of soriz or are causative agents of diseases of agricultural crops that can be used in crop rotation. The virulence properties of strains isolated from sorghum were determined on plants of the genus Sorghum. To establish the range of crops sensitive to these pathogens, a number of plants belonging to other genera and families, both cultivated and weed, were tested. Artificial inoculation was carried out in the greenhouse and in the field as injection of bacterial suspension of 1×109 CFU/mL into the leaf surface and stem at all phases of the development of soriz and sorghum cultures. Accounting for artificial contamination was carried out in 7 to 14 days using a locally modified 6-point scale. Aggressiveness of bacteria was assessed by the size of necrosis that formed at the site of injection of the bacterial suspension. Aggressiveness was calculated as the arithmetic mean of the results. Results. P. syringae strains isolated from soriz were found to be virulent for soriz and sorghum crops, however, heterogeneous in aggressiveness. The most aggressive strains were P. syringae 211141a, 210341, and 21034. Some collection strains, isolated from different cultures, showed higher aggressiveness against sugar and grain sorghum than against soriz and Sudan grass. The studied strains of phytopathogens were found to affect segetal vegetation; the most sensitive to the studied strains were horsetail, field bindweed, goldenrod. They showed high aggressiveness against setaria, ragweed, and common sedge. Strains of P. syringae affecting potato, beet, sunflower and tomato plants were identified. Conclusion. Pseudomonas syringae strains isolated from contaminated sorghum plants are virulent and capable of infecting a wide range of plants, including plants of the sorghum family, other types of agricultural crops, and various types of segetal vegetation. Strains of Pectobacterium carotovorum, Xanthomonas vasicola pv. holcicola, Diskeya chryzanthemy, Pantoea agglomerans can be potential pathogens of sorghum crops. The results indicate that segetal vegetation can serve as a reservoir of bacterial infections and play a role in the transfer of bacterial pathogens.

Pathogenicity of two lineages of infectious hematopoietic necrosis virus (IHNV) to farmed rainbow trout (Oncorhynchus mykiss) in South Korea

In May 2015, a high mortality event in farmed rainbow trout occurred in Jeollabuk-do province in Korea. Histopathological analysis revealed necrosis in the kidney, liver, branchial arch, and gills of moribund fish, and infectious hematopoietic necrosis virus (IHNV) was detected in the lesions by immunohistochemistry. Cytopathic effects were observed in EPC, FHM, and RTG-2 cell lines after inoculation with kidney and spleen tissues and IHNV was detected by reverse transcription polymerase chain reaction (PCR). The amplified PCR product was sequenced, and phylogenetic analysis placed IHNV in the JRt Nagano group. Both in vivo and in vitro trials were performed to compare the virulence properties between RtWanju15 isolate, which causes 100% mortality in imported fry, and a previous isolate RtWanju09 of the JRt Shizuoka group isolated from eggs of healthy broodfish. In vivo challenge with high dose on specific pathogen free (SPF) rainbow trout fry performed in Denmark with isolates RtWanju09, RtWanju15 and DF04/99 isolates showed a survival rates of 60%, 37.5% and 52.5% (average), respectively without statistical difference. The replication efficiency of the two isolates in the in vitro challenge was similar.