Virulence Characteristics Research Articles

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.

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.

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.

Virulence plasmid with IroBCDN deletion promoted cross-regional transmission of ST11-KL64 carbapenem-resistant hypervirulent Klebsiella pneumoniae in central China

BackgroundCarbapenem-resistant and hypervirulent Klebsiella pneumoniae (CR-hvKP) caused infections of high mortality and brought a serious impact on public health. This study aims to evaluate the epidemiology, resistance and virulence characteristics of CR-hvKP and to identify potential drivers of cross-regional transmission in different regions of China, in order to provide a basis for developing targeted prevention measures.MethodsClinical K. pneumoniae strains were collected from Jiujiang and Nanchang in Jiangxi province between November 2021 to June 2022. Clinical data of patients (age, sex, source of infection, and diagnosis) were also gathered. We characterized these strains for their genetic relatedness using PFGE, antimicrobial and virulence plasmid structures using whole-genome sequencing, and toxicity using Galleria mellonella infection model.ResultsAmong 609 strains, 45 (7.4%) CR-hvKP were identified, while the strains.isolated from Nanchang and Jiujiang accounted for 10.05% (36/358) and 3.59% (9/251). We observed that ST11-KL64 CR-hvKP had an overwhelming epidemic dominance in these two regions. Significant genetic diversity was identified among all ST11-KL64 CR-hvKP cross-regional transmission between Nanchang and Jiujiang and this diversity served as the primary driver of the dissemination of clonal groups. Virulence genes profile revealed that ST11-KL64 CR-hvKP might harbour incomplete pLVPK-like plasmids and primarily evolved from CRKP by acquiring the hypervirulence plasmid. We found the predominance of truncated-IncFIB/IncHI1B type virulence plasmids with a 25 kb fragment deletion that encoded iroBCDN clusters.ConclusionST11-KL64 is the most cross-regional prevalent type CR-hvKPs in Jiangxi province, which mainly evolved from CRKPs by acquiring a truncated-IncHI1B/IncFIB virulence plasmid with the deletion of iroBCDN. Stricter surveillance and control measures are urgently needed to prevent the epidemic transmission of ST11-KL64 CR-hvKP.

Detection of virulent and ESBL-resistant Salmonella species from cattle and associated farm environment

The aim of this study was to explore the virulence characteristics and antibiotic resistance in Salmonella species isolated from cattle farms. During the study, 10 cattle farms were selected and from each farm, 35 samples consisting of faeces, milk, udder swabs, hand swabs, floor swabs, animal drinking water, pit water, composite fodder sample, and dairy utensil swabs were collected. Accordingly, 350 samples were collected from 10 farms and processed for the detection of Salmonella spp. Presumptive Salmonella isolates were confirmed by PCR and characterized for virulence and antibiotic resistance genes. From 350 samples, 19 (5.40%) Salmonellae were recovered, and out of 19 Salmonellae, 12 were ESBL producers. Similarly, out of 19 isolates, spvC was the predominant gene detected (42.10%), followed by stn (31.5%), and spvR (26.31%), whereas, invA, and iroB genes were detected in all 19 Salmonella isolates. Most of the Salmonella isolates were multi-drug resistant strains exhibiting resistance to nalidixic acid (94.73%), tetracycline (36.84%), and ceftazidime (42.10%). Out of 12 ESBL-positive Salmonellae, 9 (75%) isolates harboured ESBL genes, viz. blaSHV and blaTEM (25% each) and blaCTX-M and blaOXA (16.66% each). Six Salmonella isolates showed the presence of tetA gene. The current study indicated healthy cattle and the associated farm environments could be a source of virulent and drug-resistant Salmonellae. The current study also advocates phenotypic and genotypic antibiotic resistance monitoring at farm animal premises and agricultural ecosystems.

The first complete genome of Robbsia andropogonis reveals its arsenal of virulence system causing leaf spot disease of areca palm

Robbsia andropogonis is one of the most destructive leaf spot disease pathogens of numerous host plants and causes heavy economic damage. In the present study, the complete genome of R. andropogonis strain BLB1, causing the leaf spot disease of areca palm, was generated using a hybrid method combining ONT PromethION long reads and BGISEQ-500 short reads. The resulting genome consists of seven replicons totaling 6,828,120 bp, and 5,808 genes were annotated, including 788 virulence-related genes. Function analysis showed that genes involved in metabolism were the most abundant group. Impressively, the bacteria were well-equipped with four, two, and four sets of type three, four, and six secretion systems, respectively, highlighting the virulence features of R. andropogonis BLB1. As the first complete genome sequence of the species of genus Robbsia, the BLB1 genome provides a solid foundation for investigation of mechanisms underlying the pathogen virulence and disease control, and will promote further discovery and characterization of the genus Robbsia.

Safety assessment of enterocin-producing Enterococcus strains isolated from sheep and goat colostrum

BackgroundThis study investigates the safety evaluation of enterocin-producing 11 E. mundtii and two E. faecium strains previously isolated from small livestock colostrums. Enterococcus species do not possess Generally Recognized as Safe (GRAS) status. Hence, it is critical to scrutinize enterococci’s antibiotic resistance, virulence characteristics, and biogenic amine production capabilities in order to assess their safety before using them as starter or adjunct cultures.ResultsEnterococcus strains showed susceptibility to medically significant antibiotics. Multiple-drug resistance (MDR) was found in only E. faecium HC121.4, and its multiple antibiotic resistance (MAR) index was detected to be 0.22. The tetL and aph(3')-IIIa were the most commonly found antibiotic resistance genes in the strains. However, E. mundtii strains HC56.3, HC73.1, HC147.1, and E. faecium strain HC121.4 were detected to lack any of the antibiotic resistance genes examined in this study. Only E. mundtii HC166.3 showed hemolytic activity, while none of the strains engage in gelatinase activity. The strains were identified to have virulence factor genes with a low rate. None of the virulence factor genes could be detected in E. mundtii HC26.1, HC56.3, HC73.1, HC165.3, HC166.8, and E. faecium HC121.4. The E. mundtii HC73.2 strain displayed the highest presence of virulence factor genes, namely gelE, efaAfs, cpd, and ccf. Similarly, the E. mundtii HC112.1 strain showed a significant presence of genes efaAfm, ccf, and acm. There was no decarboxylation of histidine, ornithine, or lysine seen in any of the strains. Nevertheless, E. faecium HC121.4 and HC161.1 strains could decarboxylate tyrosine, but E. mundtii HC26.1, HC56.3, HC73.1, HC73.2, HC112.1, HC147.1, HC155.2, HC165.3, HC166.3, HC166.5, and HC166.8 strains only showed a limited capacity for tyrosine decarboxylation. None of the strains possessed the hdc, odc, or ldc genes, but all of them had the tdc gene.ConclusionThe E. mundtii HC56.3 and HC73.1 strains were deemed appropriate for utilization in food production. Using the remaining 11 strains as live cultures in food production activities could pose a possible risk to consumer health.

Campylobacter jejuni from no antibiotics ever (NAE) broilers: prevalence, antibiotic resistance, and virulence genes analysis

Campylobacter jejuni (C. jejuni) is a leading foodborne illness causing bacteria, and poultry is a major reservoir of this pathogen. With the recent increase in broiler production under the “no antibiotics ever” (NAE) system, this study aimed to assess the prevalence, antibiotic resistance, and virulence characteristics of C. jejuni isolated from NAE raised broilers. A total of 270 cloacal swabs were collected from the live-hang areas of three commercial processing plants over 9 weeks. Each processing plant was visited three times at a one-week interval, and 30 samples were collected per visit. Among the total 270 cloacal swab samples, C. jejuni was isolated from 44 (16.3%) samples . Of these isolates, 65.9% possessed toxin-producing genes cdtA, cdtB, and cdtC, and invasion gene ciaB. The prevalence of antibioitc resistance genes aph (3’)-IIIa, erm(B) were 59.1%, and 50%, respectively. Nine (20.45%) C. jejuni isolates were identified as multidrug resistant (MDR), and 18 (40.9%) isolates showed resistance to at least one tested antibiotic. The highest resistance was observed against tetracycline (29.5%), followed by nalidixic acid (25%), whereas 22.7% of isolates were resistant to two clinically important antibiotics, azithromycin and ciprofloxacin. These results suggest that there ishigh prevalence level of multi-drug resistant C. jejuni with toxin producing virulence genes in the NAE-raised broilers sampled in this study, indicating the potential for serious human illnesses if transmitted through the food chain.

Virulence of Puccinia coronata var avenae f. sp. avenae (oat crown rust) in Canada during 2016 to 2020 and comparison of extensive vs intensive sampling methods

Puccinia coronata var avenae f. sp. avenae (Pca), the causal fungus of crown rust of oats, is a significant threat to oat production in the eastern prairie region (Manitoba and eastern Saskatchewan; EPR), Ontario and Quebec (eastern Canada; EC), in Canada. Development of oat lines with effective resistance to Pca has been a priority for oat breeding programmes in Canada, and helped mitigate reductions in oat yield and quality. This requires knowledge of the virulence characteristics of the Pca population in Canada. Our objectives were to determine the incidence and severity of Pca in Canada, the presence and frequency of virulence and races in Pca populations and compare the traditional extensive sampling method (few isolates per field from many fields) to an intensive sampling method (many isolates per field from a few fields) for obtaining genetically diverse collections. The incidence and severity of crown rust of oat in Canada was lower in 2016 to 2020 than has been reported in previous years. Virulence to all the 24 Pc genes studied was observed over the 5 years in EC and the EPR. The most effective genes were Pc94, Pc98 and Pc101 in EC and Pc50, Pc96, Pc97 and Pc98 in the EPR. Approximately 81% of 424 races identified were of unique virulence phenotypes over the 5 years, indicating a highly variable Pca population in Canada. Races JTQG-91 and GTQG-91 were the most common races identified. Collections of Pca obtained using the extensive sampling method were observed to be more genetically diverse than collections obtained using the intensive sampling method in 2018 and 2020, but not in 2019.

Molecular characterization of virulence and antibiotic resistance genes and genotyping of Listeria monocytogenes isolated from cheese, beef, chicken, and milk

Molecular characterization of virulence and antibiotic resistance genes and genotyping of Listeria monocytogenes isolated from cheese, beef, chicken, and milk

Unravelling Virulence Activities of Hospital Isolated Acinetobacter baumannii: Exploring The Prospective Application of Aspirin as an Antivirulence Agent

Acinetobacter baumannii infections pose a global public health threat due to the increasing resistance to various antimicrobial agents. This study reports the virulence characteristics of A. baumannii strains isolated from patients at Hospital Canselor Tuanku Muhriz UKM (HCTM) and explores the potential of aspirin as an antivirulence agent. Fourteen A. baumannii isolates from various infection sites exhibited resistance to at least two antibiotics. Among them, 43% (n=6) displayed high motility, correlating with the site of isolation. Additionally, 58% (n=7) formed strong biofilms, 36% (n=5) secreted proteases and 36% (n=5) resisted oxidative stress. Notably, isolates Ab_H4 and Ab_H10 displayed the highest virulence, warranting further investigation. Molecular analysis using polymerase chain reaction (PCR) showed that both Ab_H4 and Ab_H10 possessed the bap and katG genes. Although both strains were capable of secreting proteases, only Ab_H4 possessed the cpaA gene, suggesting the involvement of other genes in protease secretion in Ab_H10. Despite high motility, no pilT gene was detected in any isolates. Treatment with sub-inhibitory concentrations of aspirin (3.25 mg/ml) restored susceptibility to previously resistant antibiotics, disrupted biofilm formation and reduced proteases and catalases secretion. However, no significant impact on bacterial motility was observed. Interestingly, sub-inhibitory concentrations of aspirin induced biofilm formation in the environmental strain control (Ab_UKMCC), which was significantly reduced upon exposure to the MIC. These findings highlight the high virulence capabilities of several strains isolated from HCTM and show the potential of aspirin as an antivirulence agent, offering valuable insights for combating A. baumannii infections.

Description of three new Pseudomonas species isolated from aquarium fish: Pseudomonas auratipiscis sp. nov., Pseudomonas carassii sp. nov. and Pseudomonas ulcerans sp. nov

Pseudomonas species constitute a significant group of pathogens in aquarium fish and frequently cause haemorrhagic septicaemia. This study conducted a taxonomic characterization of Pseudomonas isolates from aquarium fish exhibiting deep ulceration and general disease signs. A polyphasic approach was employed to ascertain the taxonomic affiliation of the strains. The overall genome relatedness indices of digital DNA–DNA hybridization (dDDH) and average nucleotide identity (ANI) between the strains and the other members of the genus Pseudomonas were found to be below the established thresholds of 70 and 95–96%, respectively. Whole-genome based phylogenetic analysis revealed that strains 119PT and 120P were closely related to P. arcuscaelestis. Strain 137PT was related to P. peradeniyensis, while strains 147PT and 148P were closely related to P. japonica. The morphological, physiological, and biochemical characteristics of the strains and the genome relatedness indices of dDDH and ANI below the established thresholds confirmed the classification of the strains as three novel species. Genome analyses of the strains were also conducted to determine their biosynthesis-related gene clusters, virulence features and ecological distribution patterns. Based on polyphasic characterization, the strains 119PT, 120P, 137PT, 147PT, and 148P are novel species within the genus Pseudomonas, for which the following names are proposed: Pseudomonas auratipiscis sp. nov., with the strain 119PT as the type strain (=DSM 117162 T, =LMG 33381T); Pseudomonas carassii sp. nov., with the strain 137PT as the type strain (=DSM 117060T, =LMG 33378T); and Pseudomonas ulcerans sp. nov. 147PT, as the type strain (=DSM 117163T, =LMG 33377T).