Bacterial Disease Research Articles

Silver Nanoparticulate Carriers: A Significant Development in Nanotechnology

Background: For centuries, silver has been known for its anti-bacterial effects. It also helps in the prevention and control of various infections. Silver, when synthesized in nano-size, is much more effective, so the trend of using silver nanoparticles in treating mild bacterial diseases to deadly infectious diseases has increased rapidly. Methods: Silver nanoparticles can be synthesized by physical, chemical, and biological methods. Nanoparticles are developed in different shapes and have a wide range of sizes, with the purpose of controlling the release rate and content of the drug’s dose. The nanoparticles can be administered via oral, pulmonary, dermal, and intravenous routes. Results: Silver nanoparticles have been used in treating diseases, such as cancers, diabetes, etc., by targeted drug delivery and in cosmetics, wound healing, diagnostics, water purifying, bio-imaging, air purification, etc. The research on the novel applications of silver nanoparticles merits its medical application, and this utility aspect is granting patented technologies. The utilization of silver nanoparticles has enhanced in recent times due to their effectiveness in the specified diseased state. Conclusion: Studies have indicated that the drugs developed using silver nanoparticles manifest safety as they are biocompatible; thus, silver nanoparticles display a promising role in developing futuristic medical therapeutic strategies.

Formononetin derivatives containing benzyl piperidine: A brand new, highly efficient inhibitor targeting Xanthomonas spp

IntroductionPlant bacterial diseases take an incalculable toll on global food security. The indiscriminate use of chemical synthetic pesticide not only facilitates pathogen resistance of pathogenic bacteria, but also poses a major threat to human health and environmental protection. Therefore, it is of great economic value and scientific significance to develop a new antibacterial drug with environmental friendliness and unique mechanism of action. ObjectivesTo design and synthesize formononetin derivatives based on natural products, evaluate their in vitro and in vivo antibacterial activities and elucidate the mechanisms involved. MethodsThe synthesis was carried out by classical active group splicing method. The antibacterial activities were evaluated using turbidimetry and pot experiments. The antibacterial mechanism was further investigated using scanning electron microscopy (SEM), virulence factors, defense enzymes activities, proteomics and metabolomics. Results40 formononetin derivatives containing benzyl piperidine were designed and synthesized. The antibacterial results demonstrated that H32 exhibited the most potent inhibitory effect against Xanthomonas oryzae pv. Oryzae (Xoo) with the EC50 of 0.07 μg/mL, while H6 displayed the highest inhibitory activity against Xanthomonas axonopodis pv. Citri (Xac) with the EC50 of 0.24 μg/mL. Furthermore, the control efficacy of H32 against rice bacterial leaf blight (BLB) and H6 against citrus canker (CC) was validated through pot experiments. SEM, virulence factors and host enzyme activities assay indicated that H32 could not only reduce the virulence of Xoo, but also activate the activities of defense enzymes and improve the disease resistance of host plants. The proteomics and metabolomics analysis demonstrated that H32 could inhibit the synthesis of branched-chain amino acids, make Xoo cells in a starvation state, inhibit its proliferation, weaken its virulence and reduce its colonization and infection of host cells. ConclusionFormononetin derivatives containing benzyl piperidine could be used as potentially effective inhibitors against Xanthomonas spp.

Inorganic nanoparticles: An effective antibiofilm strategy.

Biofilm is a common problem associated with human health. Pathogenicity and increase in resistance of bacteria require urgent development of effective ways for the treatment of bacterial diseases. Different strategies have been developed for the treatment of bacterial infections among which nanoparticles have shown greater prospects in battling with infections. Biofilms are resistant microbial colonies that possess resistance and, hence, cannot be killed by conventional drugs. Nanoparticles offer new avenues for treating biofilm-related infections involving multi-drug resistant organisms. They possess great antibiofilm properties, disrupting cell architecture and preventing colony formation. Green-synthesised nanoparticles are more effective and less toxic to human cells than commercially available or chemically synthesised antibiofilm nanoparticles. This review summarises the antibiofilm efficiency of plant-mediated nanoparticles and knowledge about biofilm inhibition.

Long-term monitoring of Paenibacillus larvae, causative agent of American Foulbrood, in Uruguay

Paenibacillus larvae is the causative agent of American Foulbrood (AFB), the most severe bacterial disease affecting honey bee (Apis mellifera) larvae. It was first reported in Uruguay in 1999. Here, we summarize the monitoring strategy carried out from 2001 to date, based on nationwide surveys sampling honey from colonies (2001/2002, 2011, 2021) or from honey storage tanks (2014–2019). We also discuss the actions carried out for the prevention of AFB outbreaks. Uruguay’s experience in managing AFB for nearly 25 years without antibiotic use, might provide some helpful ideas for other countries working on AFB control programs.

Seroprevalence of small ruminant brucellosis and owners knowledge, attitude and practices in Chiro and Burka Dhintu Districts, West Hararghe, Ethiopia

Brucellosis is one of zoonotic bacterial diseases with significant veterinary and public health consequences in sub-Saharan African countries, including Ethiopia. A cross-sectional study design was conducted with the objective of estimating the seroprevalence of small ruminant brucellosis and assessing owners' knowledge, attitude and practices (KAP) on brucellosis in Chiro and Burka Dhintu Districts in Eastern Ethiopia. A total sample of 444 animals were taken using a cluster based multistage sampling technique. Screening for Brucella antibodies and confirmation of positive test results were conducted using Modified Rose Bengal Plate Test (MRBPT) and indirect enzyme-linked immunosorbent assay (I-ELISA) respectively. For the questionnaire survey, 444 randomly selected sheep and goat owners were interviewed using a pretested structured questionnaire. The overall seroprevalence of small ruminant brucellosis was found to be 6.5 % (95 % CI: 4.6–9.3). The multivariable logistic regression analysis identified sex and age as potential risk factors (P < 0.05). More specifically, females were 3.4 times (AOR = 3.4, 95 % CI: 1.2–9.2) more likely to become seropositive than their counterparts, and the odds of seropositivity in adult sheep and goats was 5.6 times (AOR = 5.6, 95 % CI: 1.3–24.7) higher than that of young animals. The knowledge, attitude and practices of animal owners with regard to brucellosis were low, and the level of education was independently associated with the owners’ knowledge and attitude. Moderate seroprevalence, combined with inadequate knowledge, attitudes, and practices of animal owners, makes small ruminant brucellosis a threat to animals and the entire community. Hence, strengthening veterinary services and raising community awareness about the disease is essential to reduce the impact on small ruminant productivity and minimize the risks to public health.

The in vitro Antimicrobial Effects of Hydrolysable and Condensed Tannin Extracts on Escherichia coli Isolated from Pathological Samples of Deceased Poultry

Abstract Colibacillosis, caused by avian pathogenic Escherichia coli (APEC), is one of the most prevalent and economically damaging bacterial diseases affecting poultry globally. Managing colibacillosis is difficult and frequently ineffective because APEC strains have developed widespread resistance to antibiotics, and the strict regulations and public concerns towards using antimicrobial agents in poultry further complicate the situation. This study aimed to evaluate the antibacterial properties of hydrolysable (sweet chestnut extract) and condensed (quebracho extract) tannins on Escherichia coli (E. coli) isolates from poultry, exploring their potential as antibiotic alternatives in managing colibacillosis. E. coli was isolated from the internal organs of deceased poultry across 18 farms, including layers, broilers, and broiler breeders. Each isolate was assessed for the presence of APEC strain predictors (virulence genes iutA, hlyF, iss, iroN, and ompT), antimicrobial resistance to 14 antibiotics using the disc diffusion method, and the presence of resistance genes for specific antibiotics (ampicillin, gentamicin, tetracycline, and quinolones). Out of 43 isolates, 27 (62.8%) were classified as APEC, 30 (69.8%) showed resistance to three or more antibiotic classes, and 32 (74.4%) carried at least one AMR gene. The minimum inhibitory concentrations (MICs) for the hydrolysable tannins from sweet chestnut extract (Castanea sativa Mill.) (SwCh) ranged from 0.5 to 3 mg/mL, while for the condensed tannins from quebracho extract (Schinopsis lorentzii) (Que), the MICs ranged from 1.5 to 4.5 mg/mL. The results indicate that both hydrolysable and condensed tannins possess significant in vitro antimicrobial activity against APEC, offering a potentially valuable alternative for controlling colibacillosis in the poultry industry.

Sub-acute dermal toxicity of Jatropha curcas Linn. leaf extract coated silver nanoparticles (SNPs) in wistar rats

The application of different nanoparticles is underway in the development of phyto-medicines. Silver nanoparticles (AgNPs) are commonly used as coating agents to treat various bacterial and viral diseases. Their safety and potential toxicity necessitate further research to explore the development of nanoparticles coated herbal drugs. The Azadirachta indica (neem) 5% leaf extract and silver nitrate was used to prepare the silver nanoparticles (SNPs) with the biological reduction (green synthesis) method [1]. The application of silver nanoparticles (SNPs) coated with J. carcus leaf extract (JcLE) on Wistar rats showed no adverse sign of toxicity on hematological parameters except an increase in the neutrophil count and increased in total erythrocyte count (TEC) on 28th day. Similarly, serum biochemical values exhibited an increase in aspartate aminotransferase (AST/SGOT) and alanine transaminase (ALT/SGPT) with JcLE-coated SNPs in treated groups. The histopathology revealed that there was no alteration in skin architecture, however, minimal alteration was observed in the liver and kidney with dilatation of the central vein and sinusoidal space, fatty change in the liver, multifocal necrobiotic changes, cystic degeneration and mild focal glomerular atrophy and hyaline cast in the lumen of tubules of kidney. It indicates the proper absorption and excretion of SNPs from the body. There was no significant effect on hematological parameters in the rats treated with J. curcas leaf extract-coated SNP. However, the serum biochemical analysis revealed a toxic effect on the kidney.

Harnessing phages as biocontrol agents against common bacterial blight diseases in plants

Bacterial blight diseases in plants are caused by various bacterial pathogens such as Dickeya, Pectobacterium, Xanthomonas, and others. They infect a wide range of crops including potatoes, tomatoes, apples, and citrus. The impact of these diseases includes reduced crop yields, lower quality produce, and economic losses for farmers. Traditional control methods like antibiotics and copper-based compounds are becoming less effective due to the development of resistance and environmental concerns. As a result, there is growing interest in alternative strategies such as biocontrol agents (BCAs), particularly bacteriophages. Bacteriophages are viruses that infect bacteria, they offer a promising solution to agricultural disease management. Their specificity and ability to target pathogenic bacteria make them an environmentally friendly alternative to chemical interventions. By optimizing phage formulations and application protocols, bacteriophages have the potential to contribute to healthier crops, increased yields, and a more sustainable agricultural system.

Gilthead seabream mucus glycosylation is complex, differs between epithelial sites and carries unusual poly N-acetylhexosamine motifs

Gilthead seabream (Sparus aurata) is a marine finfish of economic importance in aquaculture. Despite its adaptability to varying culture conditions, gilthead seabream culture can be affected by viral, bacterial or parasitic diseases. The main route of entry of pathogens is through mucosal surfaces. Teleost external and internal surfaces are covered by mucus, mainly comprised of highly glycosylated proteins called mucins. The mucin glycans regulate pathogen growth, adhesion, virulence and inter and intra species communication. Here, we characterized the gilthead seabream mucus glycosylation, compared it to previously described species and investigated associations with microbiota. 214 glycans were identified. The majority of the glycans were found at more than one epithelial surface, but 27, 22 and 89 O-glycan structures were unique to skin, gill and intestinal sample groups, respectively. Six O-glycan core types were observed. The majority of the seabream skin and gill O-glycans were neutral with unusual poly HexNAc motifs. In contrast, seabream intestinal O-glycans were highly acidic and not of the ‘poly HexNAc’ type observed in skin and gill. Furthermore, gilthead seabream gill mucosa had less oligomannose and more complex N-glycans compared to skin and intestine. The concentration and diversity of bacteria was similar in skin, gill and intestine, but the bacterial species differed between epithelia and co-varied with glycan epitopes. The presence of a complex mucus glycosylation with plenty of glycan epitopes for bacterial foraging, suggest that the skin mucosal defense in seabream includes an abundant resident microbiota. This large library of structures provides a platform for further studies, for example aiming to identifying glycans to use for diagnostic purposes, to study host-microbe interactions or disease intervention therapies.

A Brief History of Polyclonal Antibody Therapies Against Bacterial and Viral Diseases Before COVID-19.

The use of the serum or plasma of patients or animals who have recovered from an infectious disease, or had been immunized with a relevant antigen, to treat or prevent the same infection in others began in the late 1880s when French and German scientists uncovered, one step at a time, several of the elements of the immune system's response to infection. A key finding was that the damage caused by some bacteria depends upon their secreted toxins which can be neutralized by biologic agents. Antitoxins to diphtheria and tetanus began to be manufactured in large animals in France, Germany, and the US in the 1890s and were soon being used worldwide. The impact of diphtheria antitoxin on childhood mortality was profound. Shortly after the development of antitoxins, convalescent serum began to be used for its anti-bactericidal properties thus addressing serious infections caused by non-toxin-producing organisms. The effectiveness of antitoxins and antisera was demonstrated by examining mortality rates in hospitals before and after the introduction of antitoxins, by comparisons of treated and untreated patients, by comparing early and late treatment and dosage, by examining vital data mortality trends, and by several randomized and alternate assignment trials. Antitoxins continue to have a role in the rare cases of diphtheria and other conditions largely eradicated by immunization, but serum therapy nearly disappeared from the medical armamentarium with the development of antibiotics in the 1940s. Inasmuch as new human pathogens are now emerging with unprecedented regularity as seen in the recent COVID-19 pandemic, and because specific therapies are unlikely to be available for them, plasma-based antibody therapies are likely to again carve out a niche in infectious disease control.

Early warning system for nocardiosis in largemouth bass (Micropterus salmoides) based on multimodal information fusion

The high-density culture of the recirculating aquaculture system (RAS) makes bacterial and parasitic diseases in fish likely to spread within these systems. Therefore, preventing and controlling the occurrence of fish diseases in RAS is crucial for the future development of aquaculture. However, the current circulating water system lacks early warning measures to prevent and control diseases, resulting in poor accuracy in early warning and detection of diseases. To tackle this challenge, this study introduces an early warning system for largemouth bass (Micropterus salmoides) disease, which is based on You Only Look Once vision 8 (YOLOv8), ByteTrack, Long-Short-Term-Memory(LSTM), and Fuzzy Inference System (FIS). The system utilizes the water quality, surface characteristics, and behavioral traits of diseased fish to predict and prevent disease outbreaks. The system achieved an accuracy of 79.33% for identifying infected body surface features, 80.65% for identifying diseased water quality, and 81.08% for predicting diseased behavior. The experimental results indicate that the early warning system is highly reliable and effective, achieving integrated disease identification accuracy as high as 94.08%. This study enhances the accuracy of early disease warning in fish disease conditions, achieving early warning of nocardiosis in largemouth bass. The study provides crucial technical support for the sustainable and high-quality development of the aquaculture industry.

The past, present, and future of bacterial infection control: A comprehensive review

Bacterial infections have had a huge effect on human health. They have pushed medical progress and shape public health policies. These illnesses can vary from minor issues to serious conditions like sepsis. In this chapter, we will examine the history of bacterial infections from ancient times to the present while focusing on important periods and scientific breakthroughs. In ancient times, people believed infections were caused by supernatural forces. Treatment relies on herbs and surgery without proper understanding. Renaissance gave the first insights into bacteria, leading to the germ theory of disease in the 19th century via Louis Pasteur and Robert Koch. Then, in the 20th century, antibiotics changed everything; however, antibiotic resistance became a serious problem soon after. Now, in the 21st century, new technologies in genetics and personalized medicine are boosting our efforts to fight bacterial infections. This chapter offers a historical look back at crucial scientific advancements. This study also tackles current issues like antibiotic resistance and highlights the importance of global teamwork in addressing bacterial diseases.

Dynamic transcription analysis reveals the underlying key mechanism of L-arabinose-enhanced tomato resistance to bacterial wilt

Tomato bacterial wilt caused by Ralstonia solanacearum is a serious economic soil-borne disease worldwide. L-arabinose (L-Ara) increases tomato resistance to bacterial wilt, but the resistance mechanism remains unclear. In this study, we conducted an RNA sequencing (RNA-seq) analysis of tomato root and stem that exhibited differential expression in response to R. solanacearum infection at 2 dpi and 5 dpi under L-Ara application. As a result, 797 and 5605 differentially expressed genes (DEGs) were identified in response to R. solanacearum infection at 2 dpi and 5 dpi, respectively. In particular, 4504 DEGs with 2501 up-regulated and 2001 down-regulated were presented in the stem at 5 dpi, specifying that most defense responses were expressed at the wilting stage. In the function analysis (GO and KEGG), the DEGs were primarily enriched in response to stress, cell wall, glutathione and phenylpropanoid biosynthesis and plant hormone signaling transduction. Among the DEGs, potential candidate genes related to plant hormone biosynthesis and signaling, phenylpropanoid biosynthesis, and cell wall metabolism were perceived. Furthermore, the transcription factors had high expression in ERF, bHLH, C2H2, MYB, NAC, WRKY, HD-ZIP, bZIP, MYB-related, and GRAS families. This research could provide theoretical support and valuable resources for further study of the prevention and control of bacterial wilt disease under L-Ara treatment .

Duality of H2O2 detoxification and immune activation of Ralstonia solanacearum alkyl hydroperoxide reductase C (AhpC) in tobacco

Although microbial pathogens utilize various strategies to evade plant immunity, host plants have evolved powerful defense mechanisms that can be activated in preparation for threat by infective organisms. Here, we identified one 24 kDa alkyl hydroperoxide reductase C (AhpC) from the culture supernatant of Ralstonia solanacearum strain FQY-4 (denoted RsAhpC) in the presence of host roots. RsAhpC contributes to H2O2 detoxification and the pathogenicity of R. solanacearum. However, the introduction of RsAhpC into the apoplast could activate immune defense, leading to suppression of pathogen colonization in both Nicotiana benthamiana and the Honghua Dajinyuan (HD) cultivar of N. tabacum. Consequently, overexpression of RsAhpC in the HD cultivar enhanced the resistance of tobacco to bacterial wilt disease caused by FQY-4. Overall, this study provides insight into the arms race between pathogens and their plant hosts. Specifically, it is firstly reported that plants can sense pathogen-derived AhpC to activate defenses, in addition to the role of AhpC in pathogen ROS detoxification. Therefore, the macromolecule AhpC produced by Ralstonia solanacearum has the ability to enhance plant defense as an elicitor, which provides a practical strategy for disease resistance breeding.

Molecular characterization of histone gene in golden pompano (Trachinotus ovatus) and antimicrobial activity of its derived peptides

In addition to controlling gene expression, mediating DNA folding into chromatin, and responding to immunological stimuli, histones are also thought to have antimicrobial effects. This study identified the molecular characteristics of core Histone MacroH2A2 (TOMacroH2A2) and Histone H2B 1/2 (TOH2B) from Trachinotus ovatus, and the antimicrobial potential of their derived peptides (To.mh2a and To. h2b). The open reading frames (ORFs) of TOMacroH2A2 and TOH2B from T. ovatus were 1010 bp and 375 bp, encoding polypeptides of 369 and 124 amino acids, respectively. The TOMacroH2A2 included an H2A domain and an A1pp domain, while TOH2B included an H2B domain. The amino acid sequences of TOMacroH2A2 and TOH2B demonstrated high homology with other teleost's sequences of histone macroh2a2 and histone h2b, with homologies exceeding 90 %. Expression analysis showed high expression of TOMacroH2A2 in brain, stomach, heart, and skin tissues and TOH2B in gill, brain, and skin tissues. In addition, the histone-derived peptides To. mh2a and To. h2b, synthesized based on two histone sequences from T. ovatus, exhibited typical physical characteristics of antimicrobial peptides, including positive charges, amphipathicity, hydrophobicity, and rich α-helix structure. Crucially, the vitro antibacterial results demonstrated that To. mh2a and To. h2b can inhibit the growth of various aquatic pathogens including Streptococcus agalactiae, Staphylococcus aureus, Bacillus subtilis, Acinetobacter baumannii, Aeromonas hydrophila, and Escherichia coli to varying degrees. Specifically, To. mh2a and To. h2b were capable of disrupting the cell surface structures of S. aureus and penetrating the cell membrane, leading to the leakage of cellular contents, thereby exerting their antibacterial effects. Furthermore, gel electrophoresis migration assays showed that To. mh2a and To. h2b participated in antimicrobial activity by binding to bacterial genomic DNA and reducing the migration rate of gDNA in a dose-dependent manner. The minimum effective concentration for binding to DNA was approximately 50 μM. In conclusion, our study suggested that To. mh2a and To. h2b can act as antimicrobial peptides, providing a potential strategy for controlling bacterial diseases in T. ovatus.

Antimicrobial Activity of Senna didymobotrya and Thunbergia alata Plant Extracts Against Selected Bacterial Clinical Isolates from Kericho Referral Hospital in Kenya

Bacterial infections are distributed worldwide and cause deadly infectious bacterial diseases such as skin, soft tissue and respiratory tract infections, meningitis, and tuberculosis. Bacterial infections are very common and can be easily acquired since bacteria are ubiquitous. It has challenged modern healthcare providers; conventional drugs are costly and have side effects. Therefore, alternative remedies that are easily available, affordable, and effective are needed. This study was carried out to determine the antimicrobial activity of Senna didymobotrya and Thunbergia alata crude plant extracts against Staphylococcus aureus, Streptococcus pyogenes and pseudomonas aeruginosa common in Kericho County. Plant leaves of the two plants were sourced from two sites (Bomet and Kabianga), dried, milled into powder and solvent extracted using hexane, dichloromethane: methanol ratio (1:1) and methanol. Phytochemicals present in each plant extract were evaluated using standard laboratory procedures. Antimicrobial sensitivity testing, Minimum Inhibitory Concentrations (MICs) and Minimum Bactericidal Concentration (MBC) were determined. Discs impregnated with standard antibacterial drugs were used as positive control. Leaves of T. alata and Senna didymobotrya collected from Bomet contained 7.41% and 10.4% while those from Kabianga contained 8.07% and 17.71% of extracts respectively, suggesting that site conditions do not influence the percentage of extracts. Leave extracts of S. didymobotrya and T. alata were found to be rich in alkaloids, flavonoids, terpenoids, glycosides and tannins irrespective of plant collection site, solvent of extraction. S. didymobotrya and T. alata plant extracts significantly inhibited growth of the exposed microbes in the following order: S. aureus, ≥S. pyogenes and≥ P. aeruginosa bacteria in comparison with commercial antibiotics (penicillin, chloromphenical, and erythromycin). The MIC values of the isolates ranged from 20×10-3 mg/ml to 4.8 ×10-3 mg/ml. However, bacterial inhibition by plant extracts showed re-growth of S. pyogenes after 36 hours, suggesting bacteriostatic nature. These results suggest that S. didymobotrya and T. alata leaves contain significant amounts of alkaloids, flavonoids, terpenoids, glycosides and tannins hence can be used as traditional medicine to manage S. aureus, S. pyogenes and P. aeruginosa bacteria found on human skin

First Trial of a Novel Caseous Lymphadenitis Inactivated Vaccine in South Korea: Experimental Evaluation across Various Animal Models.

Caseous lymphadenitis (CLA) is a chronic and subclinical bacterial disease of ruminants caused by Corynebacterium pseudotuberculosis (C. pseudotuberculosis) infection. Until 2014, there were no reports of CLA outbreaks in South Korea; however, the prevalence of CLA cases has steadily increased. In this study, we used recently obtained field isolates to develop the first inactivated CLA vaccine in South Korea and evaluated it in various animal models. The inactivated vaccine was evaluated for virulence and effectiveness. Mice were tested for virulence and immunization challenges, and guinea pigs and Korean Native Black Goats (KNBGs) evaluated various vaccine concentrations to determine the optimal dose and effectiveness. In the case of KNBGs, clinical symptoms were not observed after vaccination. In addition, CLA-specific IgG was detected at a significantly (p < 0.05) high level and was maintained. In histopathological evaluations, inflammation was predominantly observed in the prefemoral lymph nodes in the non-vaccinated+CHAL group. The genetic diversity of C. pseudotuberculosis, which has become widespread in South Korea, is less than 0.5% our vaccine is expected to prevent infection by a wide range of strains effectively. In summary, our CLA vaccine can potentially prevent CLA and foster the growth of South Korea's domestic KNBG industry.

Bloodstream Infections Due to Wild-Type Pseudomonas aeruginosa: Carbapenems and Ceftazidime/Avibactam Prescription Rate and Impact on Outcomes.

Pseudomonas aeruginosa is one of the major concerns among bacterial diseases even when it shows a wild-type susceptibility pattern. In 2020, EUCAST reconsidered antibiogram interpretation shifting "I" from "intermediate" to "sensible, increased exposure" with possible significant impact on antibiotic prescription. The aim of this study was to evaluate mortality in patients with P. aeruginosa bloodstream infections treated with antipseudomonal penicillins or cephalosporins vs. carbapenems and ceftazidime/avibactam. This is a retrospective observational study. All the patients with a bloodstream infection due to P. aeruginosa admitted to our hospital were enrolled. Exclusion criteria were as follows: extremely critical conditions, age <18 years, pregnancy, isolation of a strain non-susceptible to piperacillin/tazobactam and antipseudomonal cephalosporins. Patients were divided into group A (treatment with carbapenems or ceftazidime/tazobactam) and group B (treatment with antipseudomonal penicillin or cephalosporins). We enrolled 77 patients, 56 and 21 in groups A and B, respectively. The two groups were homogeneous for age, sex, and biochemical and clinical characteristics at admission. All-cause in-hospital mortality was 17/56 (30.4%) and 3/21 (14.3%) in groups A and B, respectively (p > 0.1). In group A, in-hospital BSI-related mortality was 23.2% (13/56), while it was 14.3% (3/21) in group B (p > 0.1). After multivariate analysis, only the PITT score represented a risk factor for BSI-related mortality (OR 2.917, 95% CI 1.381-6.163). Both all-cause and BSI-related mortality were comparable between the two groups. Treatment with carbapenem or ceftazidime/avibactam did not represent a protective factor for mortality in wild-type P. aeruginosa BSI.

Multisystemic inflammatory disease in Pheasantshell (Unionidae, Actinonaias pectorosa) associated with Yokenella regensburgei infection at sites experiencing seasonal mass mortality events.

Freshwater mussels are integral components of riverine ecosystems, influencing water quality, nutrient cycling, and habitat characteristics. Enigmatic freshwater mussel declines, often characterized by sudden mass mortality events, pose significant challenges to conservation efforts. The Clinch River, a freshwater biodiversity hotspot in Virginia and Tennessee, USA, has experienced several enigmatic mass mortality events since 2016. Studies have reported bacteria associated with moribund Pheasantshell (Actinonaias pectorosa) during mortality events in the Clinch River, specifically Yokenella regensburgei. Despite reports of bacterial infection, little is known about their role as pathogens. Through a multiyear case-control study, combining in-situ experiments, field surveys, histology, bacterial isolation, and high-throughput sequencing, we assessed the role of bacteria in Pheasantshell (Actinonais pectorosa) mortality at three sites in the Clinch River. Between May 2021 and December 2023, we collected 21 wild moribund free-living A. pectorosa and 68 hatchery-reared A. pectorosa maintained in silos at the same sites and investigated differences in pathology and microbiologye between groups. No silo mussels presented clinical signs of disease, or gross or microscopic lesions associated with pathological conditions leading to mortality. Our findings reveal a significant association between Yokenella regensburgei and severe multisystemic and multifocal infiltrative hemocytosis with necrosis, consistent with sepsis. Lesions associated with yokenellosis were of sufficient severity and physiological significance to explain mortality in infected hosts. Although our study does not explain the cause of these infections, it confirms that mussels at our study sites are ultimately dying with an infectious disease and that Y. regensburgei can be pathogenic in free-living mussels. Our results underscore the importance of considering bacterial diseases in wild mussel populations and emphasize the need for further research to elucidate the epidemiology and pathogenicity of Y. regensburgei. Overall, our study highlights the importance of integrated approaches combining pathology, microbiology, and epidemiology in freshwater mussel conservation efforts.

Citrus tristeza virus: A century‐long challenge for the world's citrus industries

AbstractCitrus tristeza virus (CTV) is a causal agent of diseases that have challenged the global citrus production for more than a century. The disease named ‘tristeza’, which means ‘sadness’ in Portuguese and Spanish, has spread by aphids and vegetative propagation, resulting in costly pandemics that reshaped the world citrus production by forcing the adaption of disease‐tolerant rootstocks. Furthermore, management of the second major CTV‐induced disease, stem pitting, became a unique example of the use of cross‐protection on a large nationwide scale, allowing many citrus growing regions to control the disease that could not be managed through horticultural practices. The information gathered in this review commemorates a hundred years of research on the virus and the respective diseases, which began with classical horticultural approaches and advanced toward the cutting‐edge molecular biology studies. In this regard, it is proper to mention that CTV research greatly benefited from close international collaboration between research institutions and scientists from the affected and nonaffected citrus areas. Moreover, despite the considerable initial losses caused by tristeza, the world's fresh fruit and juice concentrate citrus industries reemerged as highly productive following the research advancements, a situation that changed throughout Florida and Brazil in the past two decades or so with the outbreak of the devastating citrus greening (Huanglongbing) bacterial disease. This review encompasses past and recent advances in the CTV research positioning the citrus‐CTV pathosystem as a pivotal model system for investigating virus interactions with perennial woody hosts. The review will also serve as an updated version of the respective section on CTV in the Description of Plant Viruses that the Association of Applied Biologists manages. We dedicated this review to the 85th Birthday celebration of Prof. Moshe Bar‐Joseph, a world‐renowned plant pathologist whose half‐a‐century‐long career devoted to citrus diseases yielded many important, pioneering discoveries on CTV and other closteroviruses. Many of those are highlighted in this review. Prof. Bar‐Joseph retired from the Volcani Center, Agricultural Research Organization in Israel several years ago, yet he continues to be actively engaged in research and provides his expertise to citrus pathologists around the world in the present days.