Enteroaggregative Escherichia coli (EAEC) are a diverse group of bacteria that cause diarrhea worldwide. EAEC significantly affect travelers to endemic regions, including military personnel, and children in developing countries where EAEC infection is associated with childhood failure-to-thrive. EAEC creates thick biofilms on the intestinal mucosa, a process that is thought to contribute to the development of both diarrhea and childhood failure-to-thrive. Typical EAEC strains encode and produce just one aggregative adherence fimbriae (AAF) out of the five different AAF types. The AAF are required for aggregative adherence to epithelial cells in vitro, but the degree of importance of each of the AAF types in both biofilm formation and pathogenesis is unknown. In this study, we investigated the role of the fimbriae in EAEC biofilms by deleting the major fimbrial subunit gene for the AAF from each of the five AAF categories and observing the impact on biofilm staining from recent EAEC clinical isolates. We found that biofilm was significantly reduced in all strains when the AAF gene was deleted, and that the defect could be overcome by complementation. In this work we also describe a modified murine EAEC model appropriate for colonization studies. In an antibiotic-treated mouse colonization model, some AAF mutant strains were attenuated for colonization, including AAF/II, AAF/IV, and AAF/V isolates. We did not observe complementation of the attenuated colonization phenotype in the mouse model. However, since we found a colonization defect for several EAEC mutant strains of different AAF types, a link between the fimbriae and colonization in the mice is supported. Taken together, our results show that the AAF are required for biofilm formation, and that some AAF contribute to colonization in a mouse model.

Escherichia coli (E. coli) isolates are the main cause of urinary tract infections (UTIs) worldwide. Several virulence factors, including biofilm and virulence genes, are recognized among E. coli isolates. We aimed to investigate serological typing and virulence factors among E. coli isolated from patients with recurrent UTIs compared to healthy controls.

Pseudomonas aeruginosa is an important human pathogen that is responsible for various human infections and able to develop resistance to a variety of antibiotics. Drug encapsulation may provide sustained and more efficient drug delivery, particularly in case of the drugs with low bioavailability. This study aims to characterize the antivirulence and anti-quorum sensing (QS) properties of curcumin and ciprofloxacin dually encapsulated in chitosan NPs (Cur-Cip-CsNPs). The nanoparticles were synthesized and characterized by SEM, FT-IR, Zeta Potential, and DLS analyses. The antibacterial and antivirulence effects of the Cip-CsNPs, Cur-CsNPs, and Cur-Cip-CsNPs against P. aeruginosa strains were investigated by well diffusion, biofilm and pyocyanin quantification, swarming, swimming, twitching, and proteolytic and elastinolytic activity assays. The mRNA transcript levels of the lasIR and lasAB genes were also determined by real-time PCR. Cur-Cip-CsNPs were more potent antibacterial agents against P. aeruginosa compared with other NPs and inhibited bacterial planktonic growth at 160 mg/mL, reduced biofilm formation by 72.5-86.5% and pyocyanin levels by 80.2-80.6%, and significantly inhibited flagellar and fimbrial motility of P. aeruginosa. Furthermore, bacterial proteolysis and elastinolytic activity were reduced more efficiently by Cur-Cip-CsNPs compared with other nanoformulations. The expression of the lasI, lasR, lasA, and lasB was attenuated more efficiently by Cur-Cip-CsNPs compared with Cip-CsNPs and Cur-CsNPs. This study presents an innovative approach to overcome the challenges due to antibiotic resistance and provides a new therapeutic option against P. aeruginosa infections.

TatD is evolutionarily conserved in a variety of organisms and has been implicated in DNA repair, apoptosis, and the disruption of extracellular traps. The aim of our study was to investigate the effects of TatD on L. monocytogenes biofilms. In our previous study, the deletion of the TatD gene from L. monocytogenes (named LmTatD) increased biofilm formation. However, the underlying mechanism remains unclear. In this study, we present a detailed analysis of the structural characteristics of TatD. Bioinformatic analysis revealed that the amino acid residues DPGEGDQHEDP are fully conserved. LmTatD belongs to the Class II TatD family (TATDN3) and contains a signal peptide. Recombinant LmTatD exhibited DNase activity regardless of the DNA substrate. Mutagenesis experiments confirmed the importance of glutamic acid, histidine, and aspartic acid residues in enzymatic activity. Biofilm formation was evaluated via a crystal violet assay, confocal laser scanning microscopy, and scanning electron microscopy. rLmTatD impaired biofilm formation and reduced eDNA levels without disrupting the integrity of the bacteria within biofilms. Moreover, deficiency of LmTatD led to a significant decrease in the DNase activity of the extracellular proteins from L. monocytogenes, whereas there was an increase in biofilm formation and eDNA production during the dispersion stage. However, no significant change in the total number of biofilm or planktonic bacteria was observed at any of the time points. Additionally, the mRNA level of LmTatD in the biofilm formed by the wild-type strain at the dispersion stage was greater than that at the attachment and maturation stages. The number of planktonic bacteria for the wild-type strain at the dispersion stage was significantly greater than that for the ΔLmTatD mutant. Collectively, these data suggest that LmTatD exhibits extracellular DNase activity and regulates L. monocytogenes biofilm dispersion.

Aujeszky's disease (AD) is an acute infectious disease that infects pigs and other animals, resulting in significant economic losses and posing a threat to human health. Reliable and rapid detection methods are essential for the prevention of AD. In this study, a RAA-Cas12b assay based on recombinase-aided amplification (RAA) and CRISPR-Cas12b system was established, optimized and evaluated for the rapid detection of wild-type Pseudorabies Virus (PRV). The results can not only be detected by real-time fluorescence readout, but also can be visualized by a portable blue light instrument. There was no cross-reaction with PRV Bartha-K61 strain or other swine infectious viruses. The analytical sensitivities of the real-time PRV RAA-Cas12b assay and visual PRV RAA-Cas12b assay were determined to be 15 copies/μL with 95% confidence interval and 140 copies/μL with 95% confidence interval, respectively. A total of 31 clinical samples were detected and compared with PRV qPCR assay to evaluate the diagnostic performance of the PRV RAA-Cas12b assay. The diagnostic coincidence rate of the two assays was 100%. In summary, this convenient and reliable assay has great potential for rapid detection of wild type PRV in point-of-care testing (POCT).

Determination of antibiotic susceptibility is a crucial aspect of antimicrobial therapy. The objective of this study was to determine the specific susceptibility of Staphylococcus aureus (SA) to the antibiotic doripenem. A total of 180 clinical isolates from VRSA patients were tested against doripenem using minimum inhibitory concentration (MIC) and disk diffusion tests. The overall findings indicated that doripenem exhibited a high sensitivity level for SA isolates, with an MIC of 60μg/mL and a MIC90 of 0.5mg/mL. Additionally, the antimicrobial activity of doripenem, both alone and in combination with amoxiclav against VRSA showed consistent biofilm inhibition within 48 and 24 hours, respectively. Furthermore, these results demonstrate that doripenem maintains its high efficacy against VRSA and the combination of amoxiclav with doripenem presents a potential option for managing these resistant infections.

The inflammatory response in bone tissue often triggered by LPS is a complex process. Since LPS through TLR4 and in presence of IFNγ activates osteoclast differentiation and bone resorption, therefore, suppression of osteoclastogenesis through inhibition of TLR4 vs IFNγ mediated inflammation could be a reasonable strategy for the treatment of inflammatory bone loss. Administration of anti-TLR4 (30 mg/kg) and anti-IFNγ antibodies (6.6 mg/kg) were utilized before LPS (5 mg/kg) challenge and subsequently mice were treated with mouse IL-10 (0.02 mg/kg). Then RBMCs were isolated from different groups of mice and stimulated (in vitro) with M-CSF (10 ng/ml) and RANKL (10 ng/ml) to induce bone marrow cell differentiation in presence of LPS (100 ng/ml). The involvement of RANKL and M-CSF in the regulation of bone inflammation underlines the intricate signaling pathways. Furthermore, the study sheds light on the potential therapeutic effects of exogenous IL-10 possibly through STAT3 signaling in the RBMCs. The use of antibodies against TLR4 and IFNγ, in conjugation with IL-10in LPS bone damage model, appears to downregulate the activation of NF-κB, and reduction of many pro-inflammatory cytokines regulating the inflammatory cascade in RBMC. This suggests a promising avenue for the development of treatments aimed at mitigating bone inflammation associated with bacterial infections. Therefore, inhibition of TLR4 and IFNγ could be explored as potential therapeutic agents against LPS induced bone loss.

The Chinese poultry industry has witnessed rapid development, with laying hens playing a pivotal role. However, the escalating demand has led to an exponential increase in the population of laying hens raised, resulting in emerging challenges. Particularly during bacterial infections, substantial losses can be incurred. Presently, most farms heavily rely on antibiotics for disease prevention and control. Although this approach has yielded positive outcomes, prolonged usage may lead to the emergence of drug-resistant strains and residues. Consequently, research on alternative drugs has been initiated due to antibiotic prohibition and growing pathogen resistance. Chinese herbal medicine holds significant prominence across various domains, including animal husbandry and disease treatment, owing to its traditional roots in China. Scutellaria baicalensis is a traditional Chinese medicine derived from the dried root of the labiatae family plant Scutellaria baicalensis that possesses bitter taste and cold properties while exhibiting effects such as heat clearance, dampness elimination, lung purification, fire expulsion and heat detoxification. The aboveground components of Scutellaria baicalensis encompass stems and leaves, which yield approximately three times more than their root counterparts as traditional Chinese medicine resources. Sculltllarla bactlalensls products have been successfully applied in animal husbandry with therapeutic effects against sore throat, respiratory diseases, and heat detoxification. Therefore, in pursuit of economic sustainability, this study aims at developing an extract from Scutellaria baicalensis stems and leaves for treating respiratory bacterial infections among laying hens. The findings indicate that this extract exhibits excellent therapeutic efficacy against respiratory diseases among laying hens by reducing inflammatory cell levels within their lungs.

Leptospirosis is a widespread zoonotic disease that causes severe health complications with no approved vaccine. In this study, we have focused on LruC protein from the outer membrane of Leptospira spp. LruC protein has been considered as promising target for vaccine due to its immunogenicity and conservancy. We have identified total 13 conserved B-cell, CTL, and HTL epitopes from 22 different pathogenic Leptospira species and serovars, which were linked with 4 linkers and 3 adjuvants (HBHA, CTB, TLR4) to design 36 multiepitope vaccine constructs to study the effect of different components on vaccine effectiveness. The antigenicity, immunogenicity, and non-allergenicity of the constructs were confirmed through computational analyses. Physico-chemical properties, secondary structure, and tertiary models of the vaccine constructs were predicted and validated. Molecular docking studies were conducted with Toll-like receptors (TLR2, TLR4) to assess binding affinity, identifying three top vaccine candidates (HBHA-construct 6, CTB-construct 9, and TLR4-construct 12) for further investigation. Further, these candidates were successfully cloned into pVAX1 and pET30a vectors to prepare DNA and protein vaccines, respectively. Moreover, these multiepitope vaccines were tested in mice models to assess its immunogenicity. ELISA performed with antisera against vaccine antigen, as well as crude extract of pathogenic Leptospira species showed significant IgG responses, particularly in protein vaccines. Flow cytometry revealed increased IFN-γ producing CD4+ and CD8+ T cells, especially in the TLR4-adjuvanted vaccine groups. The microscopic agglutination test further confirmed the specificity of the antibody response to Leptospira serovars. Overall, this study demonstrates the potential of these multiepitope vaccine constructs in eliciting a robust immune response, laying the foundation for future challenge study and preclinical evaluation.

Lacticaseibacillus paracasei is widely used as a probiotic supplement and food additive in the medicinal and food industries. However, its application requires careful evaluation of safety traits associated with probiotic pathogenesis, including the transfer of antibiotic-resistance genes, the presence of virulence and pathogenicity factors, and the potential disruptions of the gut microbiome and immune system. In this study, we conducted whole genome sequencing (WGS) of L. paracasei FMT2 isolated from fecal microbiota transplantation (FMT) capsules and performed genome annotation to assess its probiotic and safety attributes. Our comparative genomic analysis assessed this novel strain's genetic attributes and functional diversity and unraveled its evolutionary relationships with other L. paracasei strains. The assembly yielded three contigs: one corresponding to the chromosome and two corresponding to plasmids. Genome annotation revealed the presence of 2,838 DNA-coding sequences (CDS), 78 ribosomal RNAs (rRNAs), 60 transfer RNAs (tRNAs), three non-coding RNAs (ncRNAs), and 126 pseudogenes. The strain lacked antibiotic resistance genes and pathogenicity factors. Two intact prophages, one Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) region, and three antimicrobial peptide gene clusters were identified, highlighting the genomic stability and antimicrobial potential of the strain. Furthermore, genes linked to probiotic functions, such as mucosal colonization, stress resistance, and biofilm formation, were characterized. The pan-genome analysis identified 3,358 orthologous clusters, including 1,775 single-copy clusters, across all L. paracasei strains. Notably, L. paracasei FMT2 contained many unique singleton genes, potentially contributing to its distinctive probiotic properties. Our findings confirm the potential of L. paracasei FMT2 for food and therapeutic applications based on its probiotic profile and safety.

Mastitis is considered one of milk-producing animals' most widespread infectious diseases. The present study evaluated the prevalence of antibiotic-resistant isolates of Staphylococcus aureus (S. aureus) including methicillin-resistant S. aureus (MRSA), β-lactam-resistant S. aureus (BRSA), aminoglycoside-resistant S. aureus (ARSA), and tetracycline-resistant S. aureus (TRSA) from the udder of dromedary camels along with the associated risk factors and the antibiogram of resistant isolates. Phylogenetic analysis of antibiotic-resistant genes with NCBI sequences was performed to check their homology. A total of 384 milk samples were collected and subjected to standard microbiological procedures to isolate S. aureus. The results revealed that 177 milk samples were found positive for subclinical mastitis (SCM) out of which 101 milk samples were found positive for S. aureus. The molecular assay found the prevalence of MRSA, BRSA, ARSA, and TRSA as 48.51 %, 46.53 %, 42.57 %, and 39.60 % by targeting the mecA, blaZ, accA-aphD, and tetK genes respectively. The study isolates significant similarities to each other and to previously reported sequences from other countries that were found by in-silico analysis, indicating the possibility of pathogen transboundary transmission. This study also revealed potential risk factors that aid in the spread of mastitis in camels. Among various risk factors, the most significant were farm hygiene, physiological status of animals, type of mastitis, teat injury, use of teat dips, and milk leakage (p < 0.05). The antibiogram of antibiotic-resistant isolates of S. aureus revealed that the highest resistance was observed against penicillin followed by amoxicillin and oxytetracycline while levofloxacin was the most sensitive drug. This study highlights the high prevalence of antimicrobial-resistant S. aureus in camel mastitis. Identified risk factors provide valuable insights into management practices that contribute to disease occurrence, aiding in the development of targeted control strategies. Additionally, antimicrobial susceptibility findings offer guidance for optimizing treatment protocols to effectively manage S. aureus-induced mastitis in camels and mitigate the spread of antimicrobial resistance.

Avian metapneumovirus (aMPV) is a viral pathogen that mainly causes respiratory signs and drops in egg production in turkeys, chickens, and ducks. Here, an aMPV subgroup C (aMPV/C) strain, designated GX22-01, was isolated and identified from severe respiratory disease in broiler breeder chickens in 2022 in Jiangsu, China, as evidenced by indirect immunofluorescence and western blotting using specific anti-viral protein antibodies and by sequence analysis of viral nucleoprotein (N) gene. N gene sequencing indicated that the GX22-01 strain shares a high identity (94.3%-99.8%) with aMPV/C isolates, especially with Chinese aMPV/C isolates from ducks and chickens, which are divided into aMPV/C cluster through N gene-based phylogenetic analysis. The aMPV/C GX22-01 strain was continuously passaged in Vero cells and the viral titers approximately reached 10 TCID/0.1 mL. Pathogenic analysis showed that aMPV/C GX22-01 strain inoculation caused respiratory signs in 2-week-old specific-pathogen-free (SPF) chickens and resulted in pathogenic damage in tracheae and lung tissues, accompanied by positive viral signals using indirect immunohistochemistry. These results provide epidemiological and pathogenic data for developing effective measures against aMPV/C infection in China.

Pseudomonas aeruginosa, a formidable opportunistic pathogen, is notorious for its ability to form biofilms and produce virulence factors that favor chronic infections, especially in cystic fibrosis patients. The misuse of disinfectants, combined with environmental leakage and biodegradation, has led to widespread exposure of microorganisms to sub-lethal concentrations of disinfectants, particularly quaternary ammonium compounds (QACs). This study investigates the interaction between QACs, specifically ethylbenzalkyl dimethyl ammonium chloride (EBAC), and the quorum sensing (QS) mechanisms governing P. aeruginosa behavior. The results demonstrate that exposure to sub-minimum inhibitory concentrations (sub-MICs) of EBAC not only enhances the biofilm-forming capability of P. aeruginosa isolates but also modulates the expression of crucial QS-regulated genes. Notably, the bacteria exhibit increased production of biofilm-associated virulence factors such as pyocyanin and elastase, and altered antibiotic susceptibility profiles, indicating a shift towards persistent infection phenotypes. These findings reveal that QAC exposure can significantly increase resistance to antibiotics and external stressors like hydrogen peroxide. These results emphasize the need to reassess the efficacy of QACs in clinical disinfection settings, particularly against P. aeruginosa infections, and highlight the potential for unintended consequences of their use regarding bacterial behavior and virulence. This study provides novel insights into the role of QACs in modulating QS-mediated virulence and antibiotic resistance, offering a new perspective on the risks associated with sub-lethal disinfectant exposure.

The bacteria's ability to respond to environmental changes is critical for their survival. This allows them to form intricate communities, withstand stress, and initiate virulence responses in hosts during infection, a phenomenon known as phenotypic switching. In this study, we investigated the role of shaking conditions on phenotype switch in multidrug-resistant and pathogenic Morganella morganii both under in vitro and in vivo conditions. The results demonstrate that M. morganii grown in non-shaking conditions, possibly causing low fluid shear, developed floccules or cellular aggregates, and substantially increased biofilm formation. Meanwhile, the bacterium grown in shaking conditions was non-flocculated and produced less biofilm. This phenotype switch leads to a significant change in the protein secretome and multidrug resistance profile. In the non-shaking condition, M. morganii secretes two main proteins of ∼80 and ∼100 kDa and displays multiple antibiotic resistance (MAR) values of 0.39. In contrast, the bacterial cell in a shaking flask secreted one prominent protein of ∼50 kDa and exhibited a lower MAR value of 0.31. These observations correspond with a significant reduction in both in vitro and in vivo virulence of M. morganii grown in non-shaking conditions, namely haemolysin, swimming motility, histomorphological changes, and survival assay as compared to bacterial cells in a shaking flask displayed higher virulence in both in vitro and in vivo condition. Furthermore, non-shaking tube-grown cells have higher expression of saa, astA, ibeA, papC and papG genes as compared to cells grown in the shaking flask exhibiting higher expression of kpsMT K1, kpsMT "K5", stx, ireA and cdt genes. Taking together, the study offers strong evidence supporting the presence of two phenotype forms in the multidrug-resistant and pathogenic M. morganii strain, showing differential phenotypes. Additionally, since water flow and movement are prevalent characteristics in aquaculture systems, they can exert fluid shear on the resident microbial communities. Therefore, our study could serve as a foundation for understanding the behavior of M. morganii in aquaculture settings and enable the possibility of monitoring and controlling this multidrug-resistant and pathogenic bacterium by steering phenotypes.

Bovine campylobacteriosis is a distributed worldwide disease caused by Campylobacter fetus. It is a sexual transmitted disease that affects reproductive health in cattle. The objective of this study was to use primary bovine oviduct cells as a pathogenicity model to study the virulence of Campylobacter fetus fetus and Campylobacter fetus venerealis. Both subspecies showed the ability to adhere to, invade and cause cytopathogenic effect in oviductal cells. Transmission electron microscopy revealed significant ultrastructural damage, including cytoplasmic vacuolization, nuclear condensation and mitochondrial alterations. These mitochondrial changes, such enlargement and fragmentation, suggest potential impacts on cell viability and host cellular metabolism. This study is the first to investigate the pathogenicity of both subspecies in primary bovine oviductal epithelial cells. These findings demonstrate the virulence mechanism of C. fetus in the reproductive tract, providing insights into oviductal pathogenicity and potential impacts on bovine fertility.

The opportunistic pathogen Acinetobacter baumannii has emerged as a formidable challenge in the realm of healthcare-associated infections, primarily due to its remarkable capacity to develop resistance against a diverse array of antibiotics. In response to this pressing concern, this comprehensive study aims to design and validate a rapid and highly precise diagnostic tool, known as the Loop-Mediated Isothermal Amplification (LAMP) assay, for the detection of A. baumannii and its associated aminoglycoside resistance genes. Through meticulous comparative genomic analyses, the researchers have identified a unique 299-base pair segment within the glutathione S-transferase gene that exhibits exceptional specificity to A. baumannii. This discovery has enabled the development of a LAMP-based protocol that demonstrates complete specificity, with no cross-reactivity observed against other bacterial species. Furthermore, the assay has demonstrated a remarkable sensitivity threshold, capable of detecting as few as 10 colony-forming units per reaction for both the glutathione S-transferase target and the armA aminoglycoside resistance gene. Expanding the scope of the investigation, the researchers have also explored the distribution of five key aminoglycoside resistance genes (aadB, aacC1, aadA1, aphA6, and armA) across a diverse collection of bacterial isolates. Interestingly, the study has revealed that the aphA6 gene is the most widespread, being present in all the A. baumannii samples analyzed. The successful implementation of this LAMP-based diagnostic approach not only provides a rapid and precise means of identifying A. baumannii but also offers the ability to evaluate the presence of critical aminoglycoside resistance determinants. The adaptability of this methodology to other pathogens further underscores its potential as an invaluable tool in clinical diagnostics and epidemiological investigations. By enhancing the speed and accuracy of pathogen detection, this research holds promise for improving patient management and strengthening infection control strategies, ultimately contributing to better healthcare outcomes.

Resistance in human bacterial pathogens and lack of novel antibiotic development has led to the need for new antibiotics. Therefore, the current study was focused on endophytic bacteria from Gracilaria edulis, an edible seaweed, capable of synthesizing novel bioactive compounds with potential applications in the inhibition of human pathogens. The endophyte, identified as Bacillus subtilis through 16S rRNA gene sequencing, exhibited significant antibacterial activity against bacterial human pathogens. Using GC-MS, FTIR and NMR the lead compound was identified as Pyrrolo[1,2-α] pyrazine-1,4-dione, hexahydro-3-(2-methylpropyl) (PPDHMP). Optimized media using glucose, proline, and valine significantly enhanced the production of PPDHMP which was observed by the increase in zone of inhibition. Molecular docking of PPDHMP indicated a high binding affinity to beta-lactamase, suggesting its potential as a beta-lactamase inhibitor. PPDHMP exhibited cell wall inhibitory activity and ADMET analysis revealed promising pharmacokinetic and toxicity profiles indicating its potential for further evaluation as an oral antibiotic candidate. Phytotoxicity assessments and hemolytic assay confirmed the non-toxic nature of the metabolites produced. This research highlights the immense potential of marine endophytes in addressing the escalating issue of antibiotic resistance and paves the way for innovative solutions in antimicrobial therapy.

SALMONELLA: as an important food-borne zoonotic pathogen, is found in soil and processing environment by human or animal feces, causing serious public health problems. Quaternary ammonium compounds (QACs) disinfectants are widely used in hospitals, livestock farms and food processing sites because of their low toxicity and broad-spectrum disinfection. However, sub-lethal levels of QACs disinfectants can induce bacteria to develop tolerance to disinfectants and cross-resistance to other antimicrobial agents. The acquired resistance will undoubtedly pose a threat to the prevention of antimicrobial resistance. In this study, Salmonella enterica SE211 was induced by the sub-inhibitory concentration and sub-lethal concentration of dodecyl dimethyl ammonium bromide (DDAB) in vitro. Following exposure to DDAB, the strains showed increased resistance to DDAB, doxycycline, amphenicols and fluoroquinolones, and increased sensitivity to colistin drugs. Phenotypic experiments showed that the induced strains exhibited changes in efflux pump activity, biofilm formation ability, motility and membrane characterization. Next-generation sequencing revealed mutations in induced strains involved in LPS-related genes (msbA, lptDE) and cationic antimicrobial peptide (CAMP) resistance-related genes (phoQ, pmrD). Transcriptome sequencing (RNA-seq) analysis revealed up-regulation of efflux pump genes and down-regulation of CAMP resistance, LPS and peptidoglycan related genes. Our study provided a theoretical basis for the potential consequences of disinfection failures and environmental residues of QACs disinfectants on the evolution of antibiotic resistance in salmonella. Furthermore, the induction of colistin sensitivity in salmonella by DDBA resulted in the emergence of collateral sensitivity, which offered a new strategy for drug combination applications to prevent the rise of colistin-resistant superbugs.

Phage therapy offers a promising approach to the increasing antimicrobial resistance of Klebsiella pneumoniae. This study highlights three novel lytic bacteriophages-KPAФ1, KP149Ф1, and KP149Ф2- targeting multidrug-resistant (MDR) K. pneumoniae. These phages belong to the Myoviridae and Podoviridae family and demonstrate their efficacy and stability across a wide range of temperatures (up to 60°C) and pH levels (pH 4 to 11). Genomic analysis reveals that they are free from virulence, toxicity, and antimicrobial resistance genes, making them promising candidates for therapeutic use. Among these phages, KPAФ1 showed the highest lytic activity with a 26.15% lysis against MDR K. pneumoniae isolates. Additionally, a phage cocktail comprising all three phages improved lytic efficacy to 32.30%. This study also examined the antimicrobial resistance profiles of K. pneumoniae isolates, emphasizing the critical need for alternative treatments. By effectively targeting resistant strains, these phages offer a potential candidacy to be used as a viable alternative or a complementary antimicrobial agent to traditional antibiotics, opening up the possibility for advanced phage-based therapies. The promising results from this study pave the way for developing new treatments that could significantly improve patient care and outcomes from the growing issue of resistant bacterial infections.

Varicellovirus bovinealpha (BoAHV) types 5 and 1 are closely-related, neurotropic alphaherpesviruses. BoAHV-5 is the etiological agent of non-suppurative meningoencephalitis in calves, whereas BoAHV-1 is responsible for several syndromes in cattle, including respiratory and reproductive diseases. The innate immune response mediated by TLR3 and TLR7 is crucial in controlling infection and modulating pro-inflammatory cytokines, such as IFNs. In this study, it was evaluated whether TLR3 and TLR7 agonists affect BoAHV replication and whether TLR stimulation has an effect on the IFN-λ3 response in neural cells. TLR3 and TLR7 expression in neural cells was induced by the TLR agonists, Poly I:C and Imiquimod, respectively. The antiviral effect of the agonists varied with the virus strain. TLR7 was suppressed early after BoAHV-5 infection and it was upregulated during BoAHV-1 infection. Imiquimod pre-treatment of neural cells induced higher levels of TLR7 mRNA and reduced the replication of the natural BoAHV-5/1 recombinant. In this study, TLR3 expression was completely inhibited during infection with BoAHV-5 and there was a marked up-regulation of TLR3 mRNA during BoAHV-1 infection. Poly I:C treatment up-regulated TLR3 expression in infected cells but a detrimental effect on BoAHV-5 replication was not observed. Infection of neural cells with the recombinant virus A665 stimulated TLR3 expression late in the infectious cycle. Steady levels of BoAHV-1 replication were maintained in the presence of IFN-λ3 and this cytokine was unable to slow the replication of BoAHV-5. For BoAHV-5/1 A663 strain there was a consistent induction of IFN-λ3 throughout the infection period and maximum A663 titers at advanced stages of the replication cycle were in agreement with a decrease in expression levels. The study emphasizes the importance of strain-specific factors, the infection phase and the cell type involved in virus- and agonist-induced TLR and IFN-λ3 expression. Furthermore, these results evidenced that a deeper analysis on the role and activity of TLR agonists on BoAHV infection should be conducted to evaluate their potential as preventive or therapeutic molecules.

Phytochemicals from unexplored plant species may be vital to unlocking pharmaceutical antibiotic and antiparasitic discoveries. New compounds need to be discovered to combat antimicrobial resistance. This study aimed to investigate ethanolic leaf extracts from five endemic and four indigenous plants from Cyprus for antibacterial, antileishmanial, and antioxidant activities.