Virulence Characteristics Research Articles

Molecular Characterization of Streptococcus spp. Isolated from Milk, Feces and Farm Environment of Mastitic Dairy Cows

Streptococci are the primary cause of mastitis, significantly impacting the dairy industry economically. This study aimed to explore the molecular epidemiology, antimicrobial resistance, and virulence characteristics of Streptococcus spp. isolated from the milk, feces, and environment of dairy cows with mastitis. Sixty (60) samples (milk = 20, feces = 20 and soil = 20) from cows with clinical mastitis (CM) were purposively collected and examined. Samples were enriched in Luria Bertani broth (LB) and Streptococcus spp. was isolated on Modified Edwards Medium and confirmed by ribosomal (16S rRNA) gene sequencing. Twenty-two (36.67%) of the samples were positive for Streptococcus spp. (milk = 40.90%, feces = 31.82% and soil = 27.28%) by cultural and molecular examination. Phylogenetic analysis revealed 59.5, 30.5, 6.0% and 4.0 % of the Streptococcus isolates as S. uberis, S. agalactiae, S. hyovaginalis and S. urinalis, respectively. The milk samples had higher prevalence (42.75%) of S. uberis mastitis than feces (36.80%) and soil (20.45%) samples. Likewise, S. agalactiae was prevalent in 51.5%, 37.60% and 10.90% milk, feces and soil samples, respectively. The draft assembly sizes of G2M6 and G6M1 were 1,960,858 and 2,303,841 base pair (bp), respectively. The strains were typed as S. uberis sequence type 155 (ST155) and S. agalactiae sequence type 58 (ST58). The G2M6 genome contained 367 SEED subsystem features, 45 antimicrobial resistance genes (ARGs), and 160 virulence and virulence-related genes, whereas the G6M1 genome possessed 378 SEED subsystem features, 41 ARGs and 178 virulence genes. One plasmid replicon such as IncY of 4,012 bp, was identified in the G6M1 genome (with 95% identity and 60% coverage) while G2M6 genome harbored none. Genome completeness analysis using BUSCO revealed the presence of 100% complete BUSCOs in the hybrid assembly of both genomes. Streptococcus spp. associated with bovine mastitis exhibit a variety of genomic traits and harbor an array of ARGs and virulence genes. Further investigation is needed to identify specific traits that govern virulence fitness in the pathophysiology of mastitis. J. of Sci. and Tech. Res. 6(1): 01-12, 2024

Puccinia striiformis f. sp. tritici Exhibited a Significant Change in Virulence and Race Frequency in Xinjiang, China

Xinjiang is an important region due to its unique epidemic characteristics of wheat stripe rust disease caused by Puccinia striiformis f. sp. tritici. Some previous studies on race identification were conducted in this region, but it is still unclear how temporal changes affect the dynamics, diversity, and virulence characteristics of Pst races in Xinjiang. To gain a better understanding, we compared the race data from spring and winter wheat crops of 2022 with that of 2021. Our results showed a significant change in virulence frequency in 2022. Vr10, Vr13, and Vr19 exhibited an increasing trend, with a frequency of ≥18%, while the maximum decline was observed in Vr1, Vr3, and Vr9, with a frequency of ≤−25%. It was found that Yr5 and Yr15 remained effective against Xinjiang Pst races. The race diversity increased from 0.92 (70 races out of 345 isolates) to 0.94 (90 races out of 354 isolates) in 2022, with G22G being the dominant race group. Race CYR34 became prevalent in the region in 2022, while the LvG grouped was wiped out in 2022, from both summer and winter crop seasons. HyG and SuG groups showed an overall declining trend. Overall prevalent races showed over-summering and over-wintering behaviors in Xinjiang. The number of new races occurrence frequency increased by 34% in 2022, indicating a potential change in the population structure of Pst. It is crucial to introduce newly resistant gene cultivars in this region and to establish rust-monitoring protocols to prepare for any future epidemics.

Phenotypic and Genotypic Detection of Hypervirulent Klebsiella pneumoniae Isolated from Hospital-Acquired Infections

Hypervirulent Klebsiella pneumoniae is a highly pathogenic variant of Klebsiella pneumonae, which represents a global public health issue because it is very virulent and spreads easily. The objectives of this study were to assess the predominance of hvKp among health care-associated infections in intensive care units of Tanta University Hospital and to compare hvKp with classical K. pneumoniae (cKp) in terms of antibiotic resistance, virulence, and molecular features. The study included 300 patients suffering from HAIs from different ICUs of Tanta University Hospitals. K. pneumoniae isolates were identified and subjected to string testing and antibiotic susceptibility testing, and the tissue culture assay for biofilm formation and polymerase chain reaction (PCR) tests were performed for the identification of capsular genes (K1, K2, K57) and virulence genes (rmpA, rmpA2, iuc A). Fifty-seven K. pneumonaie isolates were isolated. A total of 21 (36.8%) of them were hvKp and 36 (63.15%) were cKp. Significantly higher antibiotic resistance was detected in the cKp group. There was a significant difference between biofilm formation between cKp and hvKp isolates (p < 0.004*). iucA, rmpA2, and K1 genes were significantly associated with hvKp. The string test shows 100% sensitivity and negative predictive value for the detection of hvKp. Consequently, using the string test alone for the screening of hvKp is required. However, combining aerobactin-positive with hypermucoviscous isolates while screening for hvKp is crucial.

Analysis of pathogenicity factors in the highly virulent Aeromonas hydrophila strain LP-2

Aeromonas hydrophila is a pervasive opportunistic fish pathogen, often leading to severe infections. However, the combination of its extensive genetic variety and the complexity of its virulence factors has hindered our ability to fully comprehend its pathogenic mechanisms to date. In this study, the pathogenicity and potential virulence factors of strain LP-2, a representative member of the high virulent ST251 clones isolated from a diseased silver carp were investigated. LP-2 was identified through Rimler-Shotts medium and 16S rRNA sequencing as A. hydrophila. Genome sequencing and comparative genomics revealed that LP-2 was an ST251-type bacterium and exhibited a genetic closeness to other fish epidemic-causing ST251 clones. Pathogenicity assays showed LP-2's robust virulence, marked by its significantly lower LD50 value (5.64 × 103 CFU) compared to the non-virulent strain ATCC 7966, as well as by its siderophore production, hemolysis, and protease activity. Moreover, using Virulence Factor Database, we identified diverse virulence genes in LP-2, with siderophore, polar flagella, and chemotaxis systems being the most prevalent. LP-2 also harbored aerolysin, enterotoxin and type IV pili (Flp and MSHA), which were commonly associated with the virulence profile of ST251. In addition, we generated 15 virulence gene deletion strains via gene recombination and assessed their impact on zebrafish survival. Notably, deleting orf00306 (enterobactin receptor) and orf03433 (ABC-type heme transporter) significantly reduced zebrafish mortality, highlighting their crucial role in LP-2 virulence. Overall, this study provides insights into the virulence characteristics of LP-2 strain, enhancing our understanding of A. hydrophila pathogenicity.

A prospective cohort study to investigate the transmission and burden of Staphylococcus aureus in Sri Lanka.

Methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of infection in both community and healthcare settings, and the household may be a central component linking these two environments. Strategies to prevent S. aureus transmission and thereby reduce the risk of infection must be informed by a detailed understanding of local epidemiology. These data are typically lacking in many low- and middle-income countries. Therefore, we aimed to investigate the circulation of infecting S. aureus strains in Sri Lanka, with a focus on the community and healthcare interface. A prospective longitudinal cohort study was performed between July and December 2021. Index patients with S. aureus infection and up to four of their household contacts were enrolled in the study. Colonization was assessed by sampling participants' nose and axilla at two time points over 3 months of follow-up. Whole-genome sequencing (WGS) was used to characterize isolates and assess strain similarity to identify transmission episodes and environmental clusters. A total of 153 participants were recruited, including 42 S. aureus-positive index patients and 111 household contacts. The baseline prevalence of S. aureus colonization amongst household contacts was 11.7% (13/111), of which 30.8% (4/13) were methicillin-resistant. A total of 88 S. aureus isolates underwent WGS and three multilocus sequence types predominated: ST672, ST5 and ST6. Each type had unique virulence characteristics but was identified in both community and healthcare environments. Colonization of household members with the index's infecting strain was not detected. S. aureus is a major cause of morbidity and mortality in low-resource settings such as Sri Lanka, yet little is known about risk factors and transmission networks. In this descriptive study, we have identified a small number of strains that appear to be well established and capable of causing both severe infection and asymptomatic colonization. Transmission of S. aureus did not appear to be occurring frequently in the household, and, therefore, preventative strategies that target high-risk groups may be more successful than universal community-based measures.

Genomic and phenotypic characterization of ST2012 clinical Klebsiella quasipneumoniae subsp. similipneumoniae harboring blaNDM−1 in China

BackgroundKlebsiella pneumoniae has emerged as a significant pathogen that causes community and hospital infections due to its high resistance rate and transmissibility. Klebsiella pneumoniae complex is classified into three phylogroups: Klebsiella pneumoniae (KpI), Klebsiella quasipneumoniae (KpII), and Klebsiella variicola (KpIII) in classical taxonomy, but KpII and KpIII are infrequently isolated clinically. Although pathogenic KpII has been reported worldwide, the understanding of this pathogen remains limited.MethodsWhole-genome sequencing (WGS) of K. quasipneumoniae subsp. similipneumoniae ACESH00366hy was performed. Plasmid characterization was demonstrated using S1-PFGE, Southern blotting, and conjugation assays. Antimicrobial susceptibility testing was performed and interpreted according to CLSI, EUCAST, and FDA standards. The virulence of the strain was assessed using the Galleria mellonella infection assay, serum-killing assay, and biofilm formation assay. A phylogenetic tree was constructed to explore its biological evolution.ResultsThe K. quasipneumoniae subsp. similipneumoniae isolate ACESH00366hy, belonging to ST2012 and KL139, contains several resistance genes including blaNDM−1, blaSHV−12, blaOKP−B−2, and oqxAB, as well as various virulence genes including iroE, iutA, mrkABCDFHIJ, entABCDEFS, and fepABCDG. The blaNDM−1 and blaSHV−12 genes were present on the 53,624 bp IncX3 plasmid. Virulence assays showed that the virulence of ACESH00366hy was greater than that of the low-toxicity strain ATCC 700,603. Phylogenetic analysis demonstrated the emergence of ST2012 KpII-B in Asia and revealed the spread of K. quasipneumoniae subsp. similipneumoniae in humans, animals, and the environment.ConclusionThis study highlights the emergence of clinical ST2012 KpII strains harbouring blaNDM−1 via the IncX3 plasmid in China. We evaluated its resistance and virulence characteristics and performed phylogenetic analysis, thereby enhancing our understanding of its resistance and pathogenicity and contributing to the clinical surveillance of K. quasipneumoniae.

First Detection of Vibrio parahaemolyticus in Migratory Birds in Egypt: Antibiogram, Virulence, and Resistance Gene Profiles Indicating Zoonotic and Public Health Risks.

This study examined the occurrence of Vibrio parahaemolyticus obtained from migrating birds, marking the first instance of such research conducted in Egypt. The study assessed potential risks using an antibiogram, virulence characteristics, antibiotic-resistance, and gene profile. Randomly collected 80 samples were tested for V. parahaemolyticus. Eleven (13.75%) samples were V. parahaemolyticus-contaminated. All isolates were positive for 16SrRNA and species-specific toxR genes. Interestingly, our strain is genetically similar to human and shrimp isolates, suggesting zoonotic transmission may pose a health danger. All isolates had 100% l-lysine decarboxylase, 45.45% beta-hemolytic, and 100% l-ornithine decarboxylase activity. All isolates displayednol-arginine decarboxylase activity. Notably, every isolate possessed a minimum of two virulence genes. In addition, the profiles of virulence genes were identified, tdh + /trh + (27.3%), tdh-/trh + (27.3%), and tdh + /trh- (45.4%). Out of the V. parahaemolyticus isolates, 18.2% (2/11) were extensively drug-resistant (XDR) to six different antimicrobials classes and possessed the blaTEM, blaOXA, sul1, and tetA genes. Furthermore, 63.6% of the isolates displayed multidrug resistance (MDR). The correlation highlights a strong relationship between phenotypic and genotypic resistance. Besides thestrong correlation between virulence and resistance genes.In summary, this work highlighted the presence of newly identified MDR and XDR V. parahaemolyticus carried toxR, trh, and tdh virulence genes, as well as blaTEM, blaOXA, sul1, and tetA resistance genes in migratory birds, indicating a significant public health risk.

Polymicrobial interactions influence Mycobacterium abscessus co-existence and biofilm forming capabilities.

The lungs of patients with cystic fibrosis (CF) are vulnerable to persistent polymicrobial colonization by bacterial pathogens including Pseudomonas aeruginosa, Staphylococcus aureus, and the non-tuberculous mycobacterium (NTM) Mycobacterium abscessus. The polymicrobial milieu within the CF lung impacts individual species fitness, influences biofilm-forming capabilities, pathogenicity, production of virulence factors and even antimicrobial responses, all potentially compromising therapeutic success. Interaction studies among these CF pathogens are very limited, especially studies on the influences of P. aeruginosa and S. aureus on M. abscessus co-existence and virulence. Based on the little known thus far about coinfection of these pathogens, we hypothesize that the co-existence of P. aeruginosa and S. aureus alters M. abscessus virulence and phenotypic characteristics. We evaluated the direct (co-culture) and indirect (using supernatant) effects of P. aeruginosa and S. aureus on M. abscessus growth rate, biofilm formation, macrophage internalization and glycopeptidolipids (GPL) expression. Our observations indicate that P. aeruginosa and S. aureus exert a competitive behavior toward M. abscessus during direct contact or indirect interaction in-vitro, probably as is the case of polymicrobial infections in the lungs of patients with CF. This is the first report that demonstrates S. aureus inhibitory effects on M. abscessus growth and biofilm forming capabilities. Collectively, co-culture studies enhance our understanding of polymicrobial interactions during coinfection and can guide to establish better management of coinfections and treatment strategies for M. abscessus.

Escherichia coli in betel leaves: prevalence, virulence characterization and antibiogram

Escherichia coli is a significant foodborne pathogen, frequently linked to hemorrhagic diarrhea, especially in developing nations, where it presents considerable public health concerns. This study was conducted to examine the virulence gene profiles and antibiotic resistance patterns of E. coli strains isolated from piper betel leaves. A total of 100 betel leaf samples, including fresh (n = 60) and ready-to-eat (n = 40) specimens, were collected and tested for the presence of E. coli using standard diagnostic techniques, such as selective culture methods, staining, latex agglutination, and polymerase chain reaction (PCR) assays. Further, the identified E. coli isolates underwent PCR-based testing for virulence genes and disk diffusion assays to assess antibiotic susceptibility. Among the 100 samples screened, 4% (n = 4/100; 95% CI: 1.57–9.84; P = 0.1126) were identified as E. coli O157, and 33% (n = 33/100; 95% CI: 24.56–42.69; P = 0.4011) were classified as non-O157 isolates. The virulence gene stx1 was found in 10.81% of isolates, while stx2, eaeA, and hlyA genes were not detected in any samples. Antibiotic resistance analysis showed that all isolates (100%, 37/37) were resistant to amoxicillin and erythromycin, with 75.68% (28/37) demonstrating resistance to tetracycline. Notably, all isolates were fully susceptible to ceftriaxone and ciprofloxacin. A majority (72.97%, 27/37) of isolates were sensitive to streptomycin, and 67.57% (25/37) were sensitive to gentamicin. Additionally, 86.48% of the E. coli isolates exhibited multidrug resistance (MDR), showing 10 resistance patterns, including 8 MDR patterns. The most common MDR pattern was AMX-TE-E, observed in 56.76% (21/37) of isolates. One isolate demonstrated resistance to six of the eight tested antibiotics across four distinct classes, with the resistance pattern AMX-TE-GEN-S-E-AZM. The MAR indices for E. coli isolates ranged between 0.25 and 0.75. These findings highlight the significant threat posed to global public health by multidrug-resistant shiga toxin-producing E. coli found on piper betel leaves in urban environments. Asian Australas. J. Biosci. Biotechnol. 2024, 9(3), 33-44

Gut Microbiome Characterisation of Chrysomya megacephala: Isolation, Identification, Antibiotic Profiling, and Initial Documentation of Leclercia adecarboxylata from the Fly

Chrysomya megacephala, known for its vector potential, harbors a diverse microbiota crucial in understanding disease transmission dynamics. Herein, we report the first documentation of Leclercia adecarboxylata isolated from C. megacephala. L. adecarboxylata is an Enterobacteriaceae, gram-negative bacillus that cause infections in human and animals. Additionally, we have reported the presence of Pseudomonas aeruginosa and Enterococcus faecalis from C. megacepahala. The study carried out the antibiotic profiling and hemolytic assays, which revealed distinct resistance patterns and virulence characteristics, shedding light on potential public health implications. L. adecarboxylata, Pseudomonas aeruginosa and Enterococcus faecalis showed positive result for hemolysis and in terms of antibiotic resistance P. aeruginosa strains showed resistance to Amoxicillin, Ampicillin and Tetracycline while, E. faecalis showed resistance towards Streptomycin and Tetracycline. However, L. adecarboxylata showed sensitivity to all antibiotics. This study was conducted from Kozhikode, Kerala, India, and this is the first of its kind of study from the region to analyse the vector potential of C. megacephala. These findings underscore the significance of comprehensive microbiological investigations in vector-borne disease surveillance and management strategies.

Biofilm-mediated antibiotic tolerance in Staphylococcus aureus from spinal cord stimulation device-related infections.

Staphylococcus aureus is a predominant cause of infections in individuals with spinal cord stimulation (SCS) devices. Biofilm formation complicates these infections, commonly requiring both surgical and antibiotic treatments. This study explored the biofilm matrix composition and antimicrobial susceptibility of planktonic and biofilm-growing S. aureus isolates from individuals with SCS-related infections. Whole-genome sequencing (WGS) examined genotypes, virulome, resistome, and the pan-genome structure. The study also analyzed biofilm matrix composition, early surface adhesion, hemolytic activity, and antibiotic-susceptibility testing. WGS revealed genetic diversity among isolates. One isolate, though oxacillin susceptible, contained the mecA gene. The median number of virulence factor genes per isolate was 58. All isolates harbored the biofilm-related icaA/D genes. When assessing phenotypic characteristics, all strains demonstrated the ability to form biofilms in vitro. The antimicrobial susceptibility profile indicated that oxacillin, rifampin, and teicoplanin showed the highest efficacy against S. aureus biofilm. Conversely, high biofilm tolerance was observed for vancomycin, trimethoprim/sulfamethoxazole, and levofloxacin. These findings suggest that S. aureus isolates are highly virulent and produce robust biofilms. In cases of suspected biofilm infections caused by S. aureus, vancomycin should not be the primary choice due to its low activity against biofilm. Instead, oxacillin, rifampin, and teicoplanin appear to be more effective options to manage SCS infections.IMPORTANCESCS devices are increasingly used to manage chronic pain, but infections associated with these devices, particularly those caused by Staphylococcus aureus, present significant clinical challenges. These infections are often complicated by biofilm formation, which protects bacteria from immune responses and antibiotic treatments, making them difficult to eradicate. Understanding the genetic diversity, virulence, and biofilm characteristics of S. aureus isolates from SCS infections is critical to improving treatment strategies. Our study highlights the need to reconsider commonly used antibiotics like vancomycin, which shows reduced activity against biofilm-growing cells. Identifying more effective alternatives, such as oxacillin, rifampin, and teicoplanin, provides valuable insight for clinicians when managing biofilm-related S. aureus infections in patients with SCS implants. This research contributes to the growing evidence that biofilm formation is crucial in treating device-related infections, emphasizing the importance of tailoring antimicrobial strategies to the biofilm phenotype.

The chosen few: Mycobacterium tuberculosis isolates for IMPAc-TB.

The three programs that make up the Immune Mechanisms of Protection Against Mycobacterium tuberculosis Centers (IMPAc-TB) had to prioritize and select strains to be leveraged for this work. The CASCADE team based at Seattle Children's Research Institute are leveraging M.tb H37Rv, M.tb CDC1551, and M.tb SA161. The HI-IMPACT team based at Harvard T.H. Chan School of Public Health, Boston, have selected M.tb Erdman as well as a novel clinical isolate recently characterized during a longitudinal study in Peru. The PHOENIX team also based at Seattle Children's Research Institute have selected M.tb HN878 and M.tb Erdman as their isolates of choice. Here, we describe original source isolation, genomic references, key virulence characteristics, and relevant tools that make these isolates attractive for use. The global context for M.tb lineage 2 and 4 selection is reviewed including what is known about their relative abundance and acquisition of drug resistance. Host-pathogen interactions seem driven by genomic differences on each side, and these play an important role in pathogenesis and immunity. The few M.tb strains chosen for this work do not reflect the vast genomic diversity within this species. They do, however, provide specific virulence, pathology, and growth kinetics of interest to the consortium. The strains selected should not be considered as "representative" of the growing available array of M.tb isolates, but rather tools that are being used to address key outstanding questions in the field.

Virulence characterization of Staphylococcus spp. isolated from mozzarella cheeses and cheese-slicers

Different species of the Staphylococcus genus can be found as contaminants in foods and may carry virulence factors that could potentially make them The enterotoxigenic potential ofpathogenic or transfer genes to other bacteria. Therefore, the aim of the present study was to isolate and identify species of Staphylococcus genus isolated from sliced mozzarella cheeses and cold-cut slicers and characterize biofilm formation in vitro, presence of enterotoxins and antibiotic resistance genes, and β-lactamase production. Sampling was carried out in 44 retail markets and isolates identified on species level. Resistance genes blaZ and mecA, as well as enterotoxin genes sea, seb, sec, and sed, were identified using PCR. Phenotypic evaluation of biofilm formation and detection of β-lactamase enzyme were also analyzed. Nine species of coagulase-negative Staphylococcus (CNS) were identified from 85 bacterial isolates. Of this total, 67.0% were positive for the presence of one or both antimicrobial resistance genes blaZ and mecA, while the β-lactamase enzyme was detected in 52.9% isolates. Regarding biofilm production, 48.2% of isolates were positive and 51.8% were negative. However, none of the isolates were identified with the enterotoxin genes. The results demonstrate the potential risk of cross-contamination, as biofilm-producing CNS could persist in the cheese retail environment, highlighting the danger of resistance genes transferring to other commensal or pathogenic bacteria.

Sous vide and chitooligosaccharide-catechin conjugate for inactivation of Vibrio parahaemolyticus and Shewanella algae in refrigerated Asian green mussel

Impacts of sous vide (SV) combined with chitooligosaccharide-catechin conjugate (COSC) on inactivation of pathogenic Vibrio parahaemolyticus and Shewanella algae in vitro and those inoculated in half-shelled Asian green mussel (H-AGM) were investigated. SV at varying temperatures (45 and 65 °C) and times (15, 30, 60, 90 and 120 min) was employed for treatment of H-AGM. SV process at 45 °C for 30 min rendered the yield of edible portion by 25.61%, maintained texture properties and inactivated vegetative microflora. COSC showed MIC/MBC toward V. parahaemolyticus and S. algae at 128/512 mg/L and 1024/4096 mg/L, respectively. For morphology, both bacterial cells had the pore and shrinkage when treated with COSC. In vitro study revealed that combining COSC (500 mg/L) with SV at 45 °C was optimal for inactivating V. parahaemolyticus and S. algae by > 6 log10 CFU/mL within 30–90 min. However, the combination of COSC and SV at 45 °C for 30 min completely inactivated V. parahaemolyticus and S. algae inoculated in H-AGM during storage at 4 °C up to 9 days. Additionally, the virulence characteristics (tdh+ and β-hemolysis positive) of inoculated pathogenic V. parahaemolyticus were not detected during the 9–day storage period. Therefore, COSC along with mild SV process was effective in preserving the quality and inhibiting microbial growth in AGM products.

Functional redundancy in Candida auris cell surface adhesins crucial for cell-cell interaction and aggregation

Candida auris is an emerging nosocomial fungal pathogen associated with life-threatening invasive disease due to its persistent colonization, high level of transmissibility and multi-drug resistance. Aggregative and non-aggregative growth phenotypes for C. auris strains with different biofilm forming abilities, drug susceptibilities and virulence characteristics have been described. Using comprehensive transcriptional analysis we identified key cell surface adhesins that were highly upregulated in the aggregative phenotype during in vitro and in vivo grown biofilms using a mouse model of catheter infection. Phenotypic and functional evaluations of generated null mutants demonstrated crucial roles for the adhesins Als4112 and Scf1 in mediating cell-cell adherence, coaggregation and biofilm formation. While individual mutants were largely non-aggregative, in combination cells were able to co-adhere and aggregate, as directly demonstrated by measuring cell adhesion forces using single-cell atomic force spectroscopy. This co-adherence indicates their role as complementary adhesins, which despite their limited similarity, may function redundantly to promote cell-cell interaction and biofilm formation. Functional diversity of cell wall proteins may be a form of regulation that provides the aggregative phenotype of C. auris with flexibility and rapid adaptation to the environment, potentially impacting persistence and virulence.

A pan-genomic analysis based multi-epitope vaccine development by targeting Stenotrophomonas maltophilia using reverse vaccinology method: an in-silico approach.

Antibiotic resistance in bacteria leads to high mortality rates and healthcare costs, a significant concern for public health. A colonizer of the human respiratory system, Stenotrophomonas maltophilia is frequently associated with hospital-acquired infections in individuals with cystic fibrosis, cancer, and other chronic illnesses. The importance of this study is underscored by its capacity to meet the critical demand for effective preventive strategies against this pathogen, particularly among susceptible groups of cystic fibrosis and those undergoing cancer treatment. In this study, we engineered a multi-epitope vaccine targeting S. maltophilia through genomic analysis, reverse vaccination strategies, and immunoinformatic techniques by examining a total of 81 complete genomes of S. maltophilia strains. Our investigation revealed 1945 core protein-coding genes alongside their corresponding proteomic sequences, with 191 of these genes predicted to exhibit virulence characteristics. Out of the filtered proteins, three best antigenic proteins were selected for epitope prediction while seven epitopes each from CTL, HTL, and B cell were chosen for vaccine development. The vaccine was refined and validated, showing highly antigenic and desirable physicochemical features. Molecular docking assessments revealed stable binding with TLR-4. Molecular dynamic simulation demonstrated stable dynamics with minor alterations. The originality of this investigation is rooted in the thorough techniques aimed at designing a vaccine that directly targets S. maltophilia, a microorganism of considerable clinical relevance that currently lacks an available vaccine. This study not only responds to a pressing public health crisis but also lays the groundwork for subsequent research endeavors focused on the prevention of S. maltophilia outbreaks. Further evidence from studies in mice models is needed to confirm immune protection against S. maltophilia.

Virulence characterization of wheat stripe rust population in China in 2023

AbstractWheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), significantly impacts global wheat production, including China. Monitoring Pst virulence is crucial for disease management. This study used 18 Yr single‐gene isogenic lines of wheat to characterize the virulence of 2023 Pst collections in China. A total of 103 isolates were collected from 11 provinces, and 61 races were identified. Frequencies of virulence to the 18 Yr genes varied from 0% to 95.1%, with low frequencies (defined as less than 10%) to Yr85 (7.8%) and Yr10 (8.7%); moderate frequencies (10%–40%) to Yr24 (15.5%), Yr32 (16.5%), YrSP (37.9%) and Yr76 (37.9%); and high frequencies (>40%) to Yr7 (47.6%), Yr1 (68.0%), Yr9 (69.9%), Yr27 (69.9%), Yr17 (79.6%), Yr6 (89.3%), YrExp2 (92.2%), Yr43 (93.2%), Yr8 (95.1%) and Yr44 (95.1%). Yr6, Yr8, Yr17, Yr27, Yr43, Yr44 and YrExp2 have almost lost their effectiveness in all provinces, while Yr10, Yr24, Yr32 and Yr85 are effective in Hebei, Shandong, Shaanxi, Gansu and Anhui. No isolate was virulent to Yr5 or Yr15, indicating their effectiveness against Pst populations in China. The Pst isolates had a wide virulence spectrum ranging from 3 to 16 virulence factors, with an average of 9.5. Comparing 2023 to 2021, the PstCN‐040 and races sharing virulence to Yr1, Yr6, Yr7, Yr8, Yr9, Yr17, Yr43, Yr44 and YrExp2 predominated, with frequencies 16.4% and 25.2%. This study provides valuable information on the virulence composition of Pst populations in China, helping to guide the development of genetic resistance for wheat in China.

Whole genome sequencing reveals antibiotic resistance pattern and virulence factors in Klebsiella quasipneumoniae subsp. Similipneumoniae from Hospital wastewater in South-West, Nigeria

Klebsiella quasipneumoniae is a distinct species from K. pneumoniae, even though it is sometimes mistaken phenotypically for the latter in clinical situations. K. quasipneumoniae is a pathogen and this study aims at understanding the genomic antibiotic resistance and virulence characteristics of Klebsiella quasipneumoniae subsp. similipneumoniae (B105 strain) isolated from tertiary hospital wastewater and the potential risks associated with its environmental spread.The Illumina platform was used for whole-genome sequencing (WGS), the generated raw reads (de novo) was assembled using RAPT NCBI, while other standardized bioinformatics tools were utilized to validate and examine the landscape of the genome's antibiotic resistance and virulence factors. The K. quasipneumoniae subsp. similipneumoniae (B105 strain), belonged to sequence type 1422 and was resistant to ampicillin, amoxicillin-clavulanic acid, ceftazidime, cefepime, meropenem, tetracycline, but susceptible to gentamicin. The annotated genome acknowledged the presence of blaOKP-B-2, ompK 36, fosA5, oqxAB, virulence genes responsible for capsule formation, lipopolysaccharide, iron uptake aerobactin (iutA), salmochelins (iroE, iroN), enterobactin siderophore, efllux pump (acrA, acrB) adherence, (mrkC, mrkD, and fimD) and two plasmids replicon IncFIB(K) and IncR. The study resonates the inadequacy of conventional microbiological identification methods to distinguish K. pneumoniae and K. quasipneumoniae and at the same time heightens the importance of using a genomic platform to extol the identity of K. quasipneumoniae subsp. similipneumoniae strain. Furthermore, the peculiarities of the acquired antimicrobial resistance and virulence genes, in this strain, are a potential risk to the environment.

Molecular Epidemiology of Pseudomonas aeruginosa in Brazil: A Systematic Review and Meta-Analysis.

Globally, Pseudomonas aeruginosa is a high-priority opportunistic pathogen which displays several intrinsic and acquired antimicrobial resistance (AMR) mechanisms, leading to challenging treatments and mortality of patients. Moreover, its wide virulence arsenal, particularly the type III secretion system (T3SS) exoU+ virulotype, plays a crucial role in pathogenicity and poor outcome of infections. In depth insights into the molecular epidemiology of P. aeruginosa, especially the prevalence of high-risk clones (HRCs), are crucial for the comprehension of virulence and AMR features and their dissemination among distinct strains. This study aims to evaluate the prevalence and distribution of HRCs and non-HRCs among Brazilian isolates of P. aeruginosa. A systematic review and meta-analysis were conducted on studies published between 2011 and 2023, focusing on the prevalence of P. aeruginosa clones determined by multilocus sequence typing (MLST) in Brazil. Data were extracted from retrospective cross-sectional and case-control studies, encompassing clinical and non-clinical samples. The analysis included calculating the prevalence rates of various sequence types (STs) and assessing the regional variability in the distribution of HRCs and non-HRCs. A total of 872 samples were analyzed within all studies, of which 298 (34.17%) were MLST typed, identifying 78 unique STs. HRCs accounted for 48.90% of the MLST-typed isolates, with ST277 being the most prevalent (100/298-33.55%), followed by ST244 (29/298-9.73%), ST235 (13/298-4.36%), ST111 (2/298-0.67%), and ST357 (2/298-0.67%). Significant regional variability was observed, with the Southeast region showing a high prevalence of ST277, while the North region shows a high prevalence of MLST-typed samples and HRCs. Finally, this systematic review and meta-analysis highlight the role of P. aeruginosa clones in critical issue of AMR in P. aeruginosa in Brazil and the need of integration of comprehensive data from individual studies.

Detection, isolation and virulence characterization of Helicobacter suis from pork products aimed to human consumption

Helicobacter suis is the most common non-Helicobacter pylori gastric Helicobacter species found in humans. Infection is associated with gastritis, peptic ulcer, gastric MALT lymphoma and neurodegenerative disorders, particularly Parkinson's disease. However, the pathogenicity of this species is still a matter of research, and results of virulence studies and antibiotic susceptibility tests tend to vary between strains. Cholesterol α-glucosyltransferase (αCgT), a known H. pylori virulence factor, appears to be present in most clinical H. suis isolates. The ability to form biofilms also plays a crucial role in the pathogenesis of H. pylori. However, no reports have been published on this ability in H. suis.H. suis is considered an emerging zoonotic pathogen, with pigs being the main source of human infection. However, there is very little information on its presence in pork, mainly due to the difficulties of its culture. Therefore, our aim was to determine the prevalence of H. suis in pork products from our geographical area by PCR and Fluorescence in situ Hybridization (FISH), as well as to isolate the bacteria and determine the antibiotic susceptibility patterns, the presence of the αCgT gene and the ability of the isolates to form biofilms.Overall, H. suis was detected in 20 of the 70 (28.6 %) samples analyzed. In 3 of them, H. suis was isolated. The αCgT gene was detected in all isolates and two of them showed a multiresistance pattern. The H. suis reference strain and two of the isolates showed “strong” to “moderate” in vitro biofilm formation ability under optimal growth conditions.Our results seem to indicate that H. suis is significantly prevalent in pork products. The combination of culture with FISH and/or mPCR proved to be a rapid and specific method for the detection, identification and direct visualization of cultivable H. suis cells from pork food products.