Site Infection Research Articles

Usefulness of a TDM-Guided Approach for Optimizing Teicoplanin Exposure in the Treatment of Secondary Bloodstream Infections Caused by Glycopeptide-Susceptible Enterococcus faecium

To assess the clinical usefulness of teicoplanin optimized by means of a therapeutic drug monitoring (TDM)-guided approach for treating secondary bloodstream infections (BSIs) caused by Enterococcus faecium. Hospitalized patients having in the period 1 March 2021–31 October 2024 a documented BSI caused by glycopeptide-susceptible Enterococcus faecium being treated with teicoplanin as definitive targeted therapy optimized by means of a real-time TDM-guided expert clinical pharmacological advice (ECPA) program were retrospectively included. Teicoplanin trough concentrations (Cmin) ranging from 20 to 30 mg/L were defined as the desired target of efficacy based on international guidelines. Univariate analysis was performed for assessing variables potentially associated with microbiological failure (defined as persistence at the infection site of the index Enterococcus faecium strain after more than 7 days from starting treatment as documented by follow-up blood cultures). Overall, 67 patients (median age 70 years; male 55.2%) were included. Catheter-related BSIs (50.7%) and intrabdominal/biliary tract (29.9%) infections were the main sources of Enterococcus faecium BSI. The desired target of teicoplanin Cmin was attained in 62.7% of patients at the first TDM assessment and significantly increased to 85.1% (p = 0.003) at subsequent TDM-guided ECPA instances during the overall treatment course. Microbiological eradication was obtained in 95% of cases (63/67). In the univariate analysis, failing effective source control was the only variable associated with an increased risk of microbiological failure (75.0% vs. 12.7%; p = 0.01). Targeted TDM-guided teicoplanin therapy, coupled with effective source control of the primary infection site by granting microbiological eradication in the vast majority of cases, may be considered a reasonable strategy for managing glycopeptide-susceptible Enterococcus faecium secondary BSIs.

PK/PD-Guided Strategies for Appropriate Antibiotic Use in the Era of Antimicrobial Resistance

Antimicrobial resistance (AMR) poses a critical global health threat, necessitating the optimal use of existing antibiotics. Pharmacokinetic/pharmacodynamic (PK/PD) principles provide a scientific framework for optimizing antimicrobial therapy, particularly to respond to evolving resistance patterns. This review examines PK/PD strategies for antimicrobial dosing optimization, focusing on three key aspects. First, we discuss the importance of drug concentration management for enhancing efficacy while preventing toxicity, considering various patient populations, including pediatric and elderly patients with their unique physiological characteristics. Second, we analyze different PK modeling approaches: the classic top-down approach exemplified by population PK analysis, the bottom-up approach represented by physiologically based PK modeling, and hybrid models combining both approaches for enhanced predictive performance. Third, we explore clinical applications, including nomogram-based dosing strategies, Bayesian estimation, and emerging artificial intelligence applications, for real-time dose optimization. Critical challenges in implementing PK/PD simulation are addressed, particularly the selection of appropriate PK models, the optimization of PK/PD indices, and considerations concerning antimicrobial concentrations at infection sites. Understanding these principles and challenges is crucial for optimizing antimicrobial therapy and combating AMR through improved dosing strategies.

The Role of the Immune Response to Helicobacter pylori Antigens and Its Relevance in Gastric Disorders

Helicobacter pylori (H.p.) is a Gram-negative bacterium endowed with gastric tropism. H.p. infection is widely spread throughout the world, accounting for various pathologies, such as peptic ulcer, gastric cancer, mucosa-associated lymphoid tissue lymphoma, and extra-gastric manifestations. This bacterium possesses several virulence factors, e.g., lipopolysaccharides (LPS), the toxins CagA and VacA, and adhesins, which elicit a robust immune response during the initial phase of the infection. Of note, the lipid A moiety of the LPS exhibits a lower endotoxic potency than that of other LPSs, thus facilitating infection through a mechanism of immune escape. H.p. colonization of the gastric mucosa induces an initial protective immune response with innate immune cells, e.g., neutrophils, monocytes, and macrophages, which engulf and kill bacteria. Moreover, the same cells, along with gastric epithelial cells, secrete cytokines and chemokines, which recruit T cells [T helper (h)1 and Th17 cells] to the site of infection, thus leading to H.p. eradication. In a large subset of individuals, the perturbation of such an immune equilibrium leads to a harmful response, with an expansion of T regulatory (TREG) cells, which suppress the protective immune response. In fact, TREG cells, via the production of interleukin (IL)-10, downregulate Th1- and Th17-related cytokines, thus allowing H.p. survival and the perpetuation of inflammation. As far as the humoral immune response is concerned, B cells, upon H.p. stimulation, produce autoreactive antibodies, and IgG anti-Lex antibodies are harmful to the gastric mucosa. In this review, the structure and function of H.p. antigenic components and immune mechanisms elicited by this bacterium will be described in relation to gastric damage.

The endothelium at the interface between tissues and Staphylococcus aureus in the bloodstream.

SUMMARYStaphylococcus aureus is a major human pathogen. It can cause many types of infections, in particular bacteremia, which frequently leads to infective endocarditis, osteomyelitis, sepsis, and other debilitating diseases. The development of secondary infections is based on the bacterium's ability to associate with endothelial cells lining blood vessels. The success of endothelial colonization and infection by S. aureus relies on its ability to express a wide array of cell wall-anchored and secreted virulence factors. Establishment of endothelial infection by the pathogen is a multistep process involving adhesion, invasion, extravasation, and dissemination of the bacterium into surrounding tissues. The process is dependent on the type of endothelium in different organs (tissues) and pathogenetic potential of the individual strains. In this review, we report an update on the organization of the endothelium in the vessels, the structure and function of the virulence factors of S. aureus, and the several aspects of bacteria-endothelial cell interactions. After these sections, we will discuss recent advances in understanding the specific mechanisms of infections that develop in the heart, bone and joints, lung, and brain. Finally, we describe how neutrophils bind to endothelial cells, migrate to the site of infection to kill bacteria in the tissues, and how staphylococci counteract neutrophils' actions. Knowledge of the molecular details of S. aureus-endothelial cell interactions will promote the development of new therapeutic strategies and tools to combat this formidable pathogen.

Root Development of Tomato Plants Infected by the Cacao Pathogen Moniliophthora perniciosa Is Affected by Limited Sugar Availability.

Moniliophthora perniciosa is the causal agent of the witches' broom disease of cacao (Theobroma cacao), and it can infect the tomato (Solanum lycopersicum) 'Micro-Tom' (MT) cultivar. Typical symptoms of infection are stem swelling and axillary shoot outgrowth, whereas reduction in root biomass is another side effect. Using infected MT, we investigated whether impaired root growth derives from hormonal imbalance or sink competition. Intense stem swelling coincided with a reduction in root biomass, predominantly affecting lateral roots. RNA-seq analyses of root samples identified only a few differentially expressed genes involved in hormone metabolism, and root hormone levels were not expressively altered. Inoculation of the auxin highly-sensitive entire mutant genotype maintained the impaired root phenotype; in contrast, the low-cytokinin MT transgenic line overexpressing CYTOKININ OXIDASE-2 (35S::AtCKX2) with fewer symptoms did not exhibit root growth impairment. Genes involved in cell wall, carbohydrate, and amino acid metabolism were downregulated, accompanied by lower levels of carbohydrate and amino acid in roots, suggesting a reduction in metabolite availability. 13CO2 was supplied to MT plants, and less 13C was detected in the roots of infected MT but not in those of 35S::AtCKX2 line plants, suggesting that cytokinin-mediated sugar sink establishment at the infection site may contribute to impaired root growth. Exogenous sucrose application to roots of infected MT plants partially restored root growth. We propose that the impairment of lateral root development is likely attributed to disrupted sugar signalling and photoassimilate supply by establishing a strong sugar sink at the infected stem.

Macrophages co-loaded with drug-associated and superparamagnetic nanoparticles for triggered drug release by alternating magnetic fields.

Two features of macrophages make them attractive for targeted transport of drugs: they efficiently take up a broad spectrum of nanoparticles (NPs) and, by sensing cytokine gradients, they are attracted to the sites of infection and inflammation. To expand the potential of macrophages as drug carriers, we investigated whether macrophages could be simultaneously coloaded with different types of nanoparticles,thus equipping individual cells with different functionalities. We used superparamagnetic iron oxide NPs (SPIONs), which produce apoptosis-inducing hyperthermia when exposed to an alternating magnetic field (AMF), and co-loaded them on macrophages together with drug-containing NPs (inorganic-organic nanoparticles (IOH-NPs) or mesoporous silica NPs (MSNs)). We show that individual macrophages can take up both SPIONs and drug-loaded NPs efficiently, thereby generating drug-loaded cells susceptible to AMF-induced cell death. Macrophages co-loaded with SPIONs and drug-containing IOH-NPs spontaneously released the drugs at similar rates irrespective of the application of an AMF. Notably, while the spontaneous drug release from macrophages co-loaded with SPIONs and drug-associated MSNs was low, AMF exposure accelerated the drug release. Thus, AMF exposure of SPION/drug-MSN coloaded macrophages provides a simple strategy for trigger-controlled drug release since it does not require any chemical modification of NPs or drugs. Thus, we assume that the coloading of different types of NPs will expand the potential of macrophages for drug delivery.

Highly viable gastrointestinal Chlamydia trachomatis in women abstaining from receptive anal intercourse

Chlamydia trachomatis (CT) may employ persistence to evade antimicrobial clearance, possibly residing in the gastrointestinal tract. This study assessed the reliability of droplet digital PCR (ddPCR) in CT detection, its functionality in viability assessment, and predictions on CT transmission dynamics by combining viability PCR (vPCR) and clinical data from 52 infected women. The ddPCR showed 94% positive and 100% negative agreement with Abbott Alinity STI-M for endocervical samples, and 92% positive and 87% negative agreement in rectal samples. Viability was higher in endocervical samples (89.1%) than in rectal samples (69.4%). Samples from participants not engaging in anal intercourse, and with non-concordant multi-locus sequence typing between rectum and endocervix, had on average the highest viability in rectum, indicating a persistent population residing in the gastrointestinal tract. This study demonstrates the effectiveness of ddPCR in detecting CT, especially in samples with high inhibition or low bacterial load, suggesting its superiority over quantitative real-time PCR. These findings support that rectal CT infection can occur independently of anal intercourse, possibly through vaginorectal contamination or oral routes. High rectal CT viability, independent of endocervical infection, indicates potential gastrointestinal establishment. Understanding CT dynamics in various infection sites can provide insights into the epidemiology and pathogenesis of CT.

Intravenous lidocaine for the treatment of sepsis-associated encephalopathy: a retrospective cohort study

ABSTRACT Objective This study aimed to evaluate the efficacy of intraoperative intravenous lidocaine administration in the management of sepsis-associated encephalopathy (SAE). Methods This retrospective cohort analysis included 165 patients diagnosed with SAE, who were categorized into two groups: the lidocaine group (n = 55) and the control group (n = 110). The lidocaine group received an intravenous injection of lidocaine at 1.5 mg/kg following anesthesia induction, and then received a continuous infusion at 1.5 mg/kg/h until the completion of surgery. The control group did not receive lidocaine during surgery. Data collected included patient demographics, medical history, infection site, Acute Physiology and Chronic Health Evaluation (APACHE) II score, Sequential Organ Failure Assessment (SOFA) score, Glasgow Coma Scale (GCS) score, laboratory results, anesthetic agents used, surgery duration, and length of stay in the intensive care unit (ICU). The primary outcome was the in-hospital prognosis of SAE. Results Patients in the lidocaine group had a significantly shorter ICU stay and a significantly higher rate of favorable prognosis compared with the control group (p < 0.05). Multivariate logistic regression analysis identified age and surgery duration as risk factors for SAE prognosis, whereas intraoperative intravenous lidocaine, GCS score, and intravenous dexmedetomidine emerged as protective factors. Conclusion Intraoperative intravenous administration of lidocaine significantly enhanced the prognosis of SAE patients.

Microbial analyses of infectious keloids on the anterior chest-a case-control study.

Some studies have confirmed that pathogens can cause infection through bacterial cultures on the surface of infectious keloids. However, further exploration of the comparison between infectious and non-infectious keloids and the bacterial flora of infectious foci is lacking. To investigate the differential flora of purulent secretions on the surface of infectious keloids compared to non-infectious keloids and to determine the microbial composition within the infectious foci. This case-control study involved 17 patients and obtained swab specimens from the surface of keloids in two groups, and from the infectious foci in the infectious group. Bacterial composition was analyzed using 16S ribosomal RNA sequencing. There were no statistical differences in the general condition of patients between the two groups. The presence of the phylum Actinobacteriota, and the orders Propionibacteriales and Corynebacteriales, as well as the genus Taibaiella, was greater on the surface of keloids in the infectious group. The most prevalent genera in infective sites were Staphylococcus, Peptoniphilus, and Cutibacterium. Microbial-associated gene pathways indicated a correlation with inflammation and tumor-like growth in keloids. There is a connection between infectious keloids and microorganisms, providing insights for predicting and treating keloid infections.

Predictors of Cryptococcus gattii clinical presentation and outcome: An international study.

Infection by Cryptococcus gattii can lead to pulmonary or central nervous system (CNS) disease, or both. Whether site of infection and disease severity are associated with C. gattii species and lineages or with certain underlying medical conditions, or both is unclear. We conducted a retrospective cohort study to identify factors associated with site of infection and mortality among C. gattii cases. We extracted data on 258 C. gattii cases from Australia, Canada and the United States reported from 1999 to 2011. We conducted unadjusted and multivariable logistic regression analyses to evaluate factors associated with site of infection and C. gattii mortality among hospitalized cases (N=218). Hospitalized C. gattii cases with CNS and other extrapulmonary disease were younger, more likely to reside in Australia and be infected with VGI lineage but less likely to have comorbidities and die as compared to pulmonary cases. The odds of having CNS and/or other extrapulmonary disease were 9 times higher in cases with VGI infection (aOR=9.21, 95%CI=3.28-25.89). Age >70 years (aOR=6.69, 95%CI=2.44-18.30), chronic lung disease (aOR=2.62, 95%CI=1.05-6.51) and an immunocompromised status (aOR=2.08, 95%CI=1.05-6.51) were associated with higher odds of C. gattii mortality. Among hospitalized cases, C. gattii species and lineage are associated with site of infection but not with the risk of death, whereas older age and comorbidities increase the risk of death.

Medical Therapy Alone for Ommaya Reservoir-Associated Bacterial Meningitis: When It Works and When It Fails.

Administration of intraventricular chemotherapy through Ommaya reservoir is indicated for certain forms of leptomeningeal disease. However, ventricular reservoirs carry a substantial risk of infection. The conventional approach to managing reservoir-associated infections involves removal of the reservoir and systemic antibiotic therapy, but this strategy necessitates additional procedures to remove and subsequently replace the device. We evaluated the success rate of standardized, multimodal medical therapy alone in treating reservoir-associated meningitis and factors associated with the need for device removal. We used the International Neoplastic Meningitis Academic Registry Consortium database to identify patients at our institution with reservoir-associated bacterial meningitis. A standardized antibiotic regimen of oral rifampin, intraventricular vancomycin, and another intravenous antibiotic based on the infecting organism was used to treat infections for 10 to 14 days. We evaluated the rate of infection clearance and factors associated with success of therapy without reservoir removal. Forty-eight infections in 33 patients (5.79% of all patients) were identified. Before infection, reservoirs were accessed a median of 6 (1-14) times. Infections were eradicated without reservoir removal in 39 of 48 patients (81.3%). Cerebrospinal fluid (CSF) leak/local wound infection was the only factor associated with the need for reservoir removal (odds ratio = 18.3 [3.68-141], P < .001) on multivariate analysis, and 98.0% of patients without this characteristic were cured with medical therapy alone. Other characteristics such as age, myelosuppression, tumor histology, number of reservoir accesses, concurrent systemic chemotherapy, or infecting organism were not predictive of reservoir removal. Random forest and gradient boost machine learning models further confirmed CSF leak/local wound infection to be the most important predictor of removal. Most patients who develop a reservoir-associated infection can be successfully treated with a standardized antibiotic regimen alone, without additional surgery for reservoir removal and subsequent replacement. However, CSF leak/reservoir site infection is strongly associated with failure of medical therapy and warrants early device removal.

ESBL- and pAmpC-producing Enterobacterales from Swedish dogs and cats 2017-2021: a retrospective study.

Antibiotic resistant bacteria are a threat to both human and animal health. Of special concern are resistance mechanisms that are transmissible between bacteria, such as extended-spectrum beta-lactamases (ESBL) and plasmid-mediated AmpC (pAmpC). ESBL/AmpC resistance is also of importance as it confers resistance to beta-lactam antibiotics including third generation cephalosporins. The Swedish Veterinary Agency (former English name National Veterinary Institute) performs confirmatory testing of suspected ESBL-/pAmpC-producing Enterobacterales. The aim of this study is to describe the clinical background, antibiotic susceptibility, and genetic relationships of confirmed isolates from dogs and cats in Sweden from 2017 to 2021. The study includes 92 isolates of ESBL/pAmpC-producing bacteria from 82 dogs, and 28 isolates from 23 cats. Escherichia coli was the most commonly isolated bacteria, and the most frequent sampling site was the urinary tract. From eight dogs and two cats, ESBL/pAmpC-producing bacteria were isolated on more than one occasion. Multi-resistance was more than twice as common in samples from dogs (50%) than in samples from cats (22%). Among dogs, sequence type (ST) 131 and ST372 were the dominant strains and blaCMY-2 and blaCTX-M-15 the dominant genes conferring reduced susceptibility to third-generation cephalosporins. Among cats, ST73 was the dominant strain and blaCTX-M-15 the dominant gene. Monitoring the resistance patterns and genetic relationships of bacteria over time is important to follow the results of measures taken to reduce resistance. Knowledge of the appropriate antibiotic usage is also crucial. In this study, a variety of STs and ESBL/pAmpC-genes were detected among the isolates. There were available antibiotics likely effective for treatment in all cases, based on resistance pattern, infection site and host species.

Doxycycline Postexposure Prophylaxis and Bacterial Sexually Transmitted Infections Among Individuals Using HIV Preexposure Prophylaxis

Doxycycline postexposure prophylaxis (doxyPEP) has been shown to decrease the incidence of bacterial sexually transmitted infections (STIs) among people assigned male sex at birth in clinical trials, but data from clinical practice are limited. To describe early uptake of doxyPEP and evaluate changes in STI incidence following doxyPEP initiation. This retrospective cohort study of adults (aged ≥18 years) dispensed HIV preexposure prophylaxis (PrEP) at Kaiser Permanente Northern California during November 1, 2022, to December 31, 2023, examined electronic health record data to compare HIV PrEP users dispensed and not dispensed doxyPEP and rates of bacterial STIs before and after starting doxyPEP. Individuals were followed up from their first recorded STI test on or after November 1, 2020, until December 31, 2023, or discontinuation of health plan membership. Pharmacy dispensing data were used to define doxyPEP recipients. Demographic and clinical characteristics were compared between individuals dispensed and not dispensed doxyPEP. Primary outcomes were incident chlamydia, gonorrhea, or infectious syphilis measured as quarterly STI positivity (proportion of individuals testing positive at least once per quarter). Among doxyPEP recipients, rate ratios (RRs) compared mean quarterly STI positivity from 24 months before to 12 months after starting doxyPEP. In an exploratory analysis, STI trends were evaluated for the full cohort, stratified by receipt of doxyPEP. Among 11 551 HIV PrEP users (mean [SD] age, 39.9 [12.1] years; 95.1% male), 2253 (19.5%) were dispensed doxyPEP, of whom 2228 (98.9%) were male and 1096 (48.6%) had an STI in the year before starting doxyPEP. Compared with individuals not dispensed doxyPEP, doxyPEP recipients were older (mean [SD] age, 40.4 [10.8] vs 39.8 [12.4] years; P = .04) and had used HIV PrEP longer (mean [SD], 4.2 [2.8] vs 3.4 [2.6] years; P < .001), and a higher proportion were commercially insured (2091 [92.8%] vs 8270 [88.9%]; P < .001). Among doxyPEP recipients, quarterly chlamydia positivity decreased from 9.6% (95% CI, 9.0%-10.3%) before starting doxyPEP to 2.0% (95% CI, 1.5%-2.6%) after starting doxyPEP (RR, 0.21; 95% CI, 0.16-0.27; P < .001), with significant declines for each anatomic site of infection. Quarterly gonorrhea positivity decreased from 10.2% (95% CI, 9.6%-10.9%) before starting doxyPEP to 9.0% (95% CI, 8.0%-10.1%) after starting doxyPEP (RR, 0.88; 95% CI, 0.77-1.00; P = .048); site-specific declines were significant for rectal (RR, 0.81; 95% CI, 0.67-0.97; P = .02) and urethral (RR, 0.56; 95% CI, 0.40-0.79; P = .001) gonorrhea, but not pharyngeal gonorrhea. Quarterly syphilis positivity decreased from 1.7% (95% CI, 1.4%-1.9%) before starting doxyPEP to 0.3% (95% CI, 0.2%-0.6%) after starting doxyPEP (RR, 0.20; 95% CI, 0.11-0.37; P < .001). Positivity for STIs remained stable in individuals not dispensed doxyPEP. This study found that receipt of doxyPEP was associated with substantial declines in chlamydia and syphilis incidence and modest declines in urethral and rectal gonorrhea incidence among individuals using HIV PrEP. These findings suggest that doxyPEP may offer substantial benefits for reducing population-level STI transmission with broader implementation.

Dual‐Cascade Responsive H2Se Delivery Nanogels Bearing Selenobenzamide as H2Se Donor for the Treatment of Multidrug Resistant Bacteria Infections

AbstractHydrogen selenide (H2Se) as one of the endogenous gaseous signaling molecules for antibacterial gas therapy, faces limitations such as high‐dose toxicity and short half‐life. Herein, a polymeric H2Se delivery nanogel (H2Se‐NG) incorporated with aldehyde‐modified selenobenzamide (SeAs) is designed for multidrug resistant (MDR) related healthcare‐associated infections (HAIs) treatment. H2Se‐NG facilitates a dual‐cascade responsive release of H2Se over 72 h, effectively addressing the safety issues caused by the rapid hydrolysis of traditional inorganic H2Se delivery methods. In vitro and in vivo studies demonstrate that nontoxic doses of H2Se‐NG at 150 µg mL−1 not only eliminated over 99% of MDR bacteria and their biofilm within 8 h while reducing levels of proinflammatory cytokines postinfection. Additionally, RNA sequencing results reveal that the released H2Se induces oxidative stress at infection site, kills biofilm‐embedded methicillin‐resistant Staphylococcus aureus (MRSA) and leads biofilm elimination by activating biofilm dispersion genes, suggesting the potential of H2Se‐NG as a promising strategy in antibacterial gas therapy.

Mucosal Immunization with an Influenza Vector Carrying SARS-CoV-2 N Protein Protects Naïve Mice and Prevents Disease Enhancement in Seropositive Th2-Prone Mice

Background/Objectives: Intranasal vaccination enhances protection against respiratory viruses by providing stimuli to the immune system at the primary site of infection, promoting a balanced and effective response. Influenza vectors with truncated NS1 are a promising vaccine approach that ensures a pronounced local CD8+ T-cellular immune response. Here, we describe the protective and immunomodulating properties of an influenza vector FluVec-N carrying the C-terminal fragment of the SARS-CoV-2 nucleoprotein within a truncated NS1 open reading frame. Methods: We generated several FluVec-N recombinant vectors by reverse genetics and confirmed the vector’s genetic stability, antigen expression in vitro, attenuation, and immunogenicity in a mouse model. We tested the protective potential of FluVec-N intranasal immunization in naïve mice and seropositive Th2-prone mice, primed with aluminium-adjuvanted inactivated SARS-CoV-2. Immune response in immunized and challenged mice was analyzed through serological methods and flow cytometry. Results: Double intranasal immunization of naïve mice with FluVec-N reduced weight loss and viral load in the lungs following infection with the SARS-CoV-2 beta variant. Mice primed with alum-adjuvanted inactivated coronavirus experienced substantial early weight loss and eosinophilia in the lungs during infection, demonstrating signs of enhanced disease. A single intranasal boost immunization with FluVec-N prevented the disease enhancement in primed mice by modulating the local immune response. Protection was associated with the formation of specific IgA and the early activation of virus-specific effector and resident CD8+ lymphocytes in mouse lungs. Conclusions: Our study supports the potential of immunization with influenza vector vaccines to prevent respiratory diseases and associated immunopathology.

Mixed DAMP/MAMP oligosaccharides promote both growth and defense against fungal pathogens of cucumber.

Plants recognize a variety of environmental molecules, thereby triggering appropriate responses to biotic or abiotic stresses. Substances containing microbes-associated molecular patterns (MAMPs) and damage-associated molecular patterns (DAMPs) are representative inducers of pathogen resistance and damage repair, thus treatment of healthy plants with such substances can pre-activate plant immunity and cell repair functions. In this study, the effects of DAMP/MAMP oligosaccharides mixture (Oligo-Mix) derived from plant cell wall (cello-oligosaccharide and xylo-oligosaccharide), and fungal cell wall (chitin-oligosaccharide) were examined in cucumber. Treatment of cucumber with Oligo-Mix promoted root germination and plant growth, along with increased chlorophyll contents in the leaves. Oligo-Mix treatment also induced typical defense responses such as MAP kinase activation and callose deposition in leaves. Pretreatment of Oligo-Mix enhanced disease resistance of cucumber leaves against pathogenic fungi Podosphaera xanthii (powdery mildew) and Colletotrichum orbiculare (anthracnose). Oligo-Mix treatment increased the induction of hypersensitive cell death around the infection site of pathogens, which inhibited further infection and the conidial formation of pathogens on the cucumber leaves. RNA-seq analysis revealed that Oligo-Mix treatment upregulated genes associated with plant structural reinforcement, responses to abiotic stresses and plant defense. These results suggested that Oligo-Mix has beneficial effects on growth and disease resistance in cucumber, making it a promising biostimulant for agricultural application.

Cophinforma tumefaciens causing Dieback disease in Litsea cubeba (Lour.) Per. in China.

Litsea cubeba (Lour.) Per., named as May Cang, is a rare deciduous evergreen tree and cultivated for its ethnopharmacological properties and medicinal uses. In 2020-2023, an outbreak of dieback disease was observed on the stems and branches of L. cubeba with above 80% disease incidence in a 150 hectare plantation in Yiyang, Hunan (N28°39'24"; E112°12'48"). In the early stages, water-soaked lesions appeared on the stems and branches. The infected sites turned elliptical in shape, dark brown, and swelled. The infected branches and stems died gradually. After scraping the bark from the diseased stems and branches under aseptic conditions, diseased tissues (5 mm2) from the diseased-healthy junction were cut off and placed on PDA containing penicillin (50 mg/L) at 25 ℃ to 28 ℃ in the dark for 3 to 4 days. Colonies from different tissues were subcultured by transferring the hyphal tip onto fresh PDA. Colonies with regular margin on PDA reached 60 mm diam after 3 d at 25℃ to 28℃, the aerial mycelia were woolly, grayish-white at first, gradually turned gray black after 14 days. No fruiting bodies were found on medium. On disease stems, conidia were hyaline, aseptate, granular, ellipsoid to obovoid, 18.0 to 33.4 × 5.5 to 9.8 μm (av. 25.6 × 7.4 μm, n=55). The internal transcribed spacers (ITS), 28S nrDNA (LSU), elongation factor 1-alpha (TEF1), and β-tubulin (TUB2) of isolate ACCC35248 and ACCC35249 (stored in the Agricultural Culture Collection of China) were PCR amplified and sequenced for further identification with primer pairs: .ITS1/ITS4 (White et al. 1990), LROR/LR7 (Rehner et al. 1994), EF1-728F/EF-2 (Zhao et al. 2021) and TUB4Rd/TUB2Fd (Woudenberg et al. 2009), respectively. Obtained sequences of ITS, LSU, TEF1 and TUB2 (Genebank accessions nos. PP577627 and PP577624, PP588412 and PP588413, PP584319 and PP584320, PP584321 and PP584322) showed above 99% homology with these sequences of Cophinforma tumefaciens ex-type culture IMI 76762 (ITS: MW810287, TEF: MZ073950 and TUB: MZ073935) and MFLUCC 11-0425 (ITS: JX64680, LSU: JX646817, TEF: JX646865 and TUB: JX646848) (Liu et al, 2012). Phylogenetic analysis with maximum likelihood in MEGA 10.0 using the concatenated ITS-TEF-TUB sequences placed the isolates within the C. tumefaciens clade with 100% bootstrap support. Therefore, the fungus was identified as C. tumefaciens. One-year-old healthy L. cubeba seedlings were surface-sterilized with 75% ethanol, then wounded with sterile needles and a 6-mm-diameter fungal plug of 14-day-old cultures grown on PDA was put on the wound. Sterile PDA plugs were used as controls, and all inoculated sites were wrapped with plastic film. The tests were repeated twice. At 7 days post-inoculation, symptoms were observed at the inoculated sites and the upper branches of the inoculation site died back two months later, while no symptoms were observed on the control plants. C. tumefaciens was re-isolated from the inoculated stems. C. tumefaciens can infect various plants and cause disease worldwide (Zhao et al. 2021), and this is the first report of a quarantine pathogen causing dieback on L. cubeba in China. This information will assist in preventing further spread of this pathogen.

An evaluation of pruning programs to manage shoot blight, caused by the bacterium Erwinia amylovora.

Fire blight is an economically devastating disease caused by the bacterium Erwinia amylovora. Infections lead can shoot blight and, when unmanaged, become systemic and can quickly cause tree death and spread through an orchard via active infections sites producing bacterial ooze. With climate change, increasingly popular high-density training systems, and the susceptibility of many consumers desired apple cultivars, shoot blight management has become exceptionally challenging despite the diverse management tactics available. To better understand pruning as a management practice, we evaluated ten pruning programs in two different orchards over the course of two years. The pruning programs in this study encompass extension recommendations and grower preferences and include a variety of supplemental chemical applications and sanitation practices to answer three primary questions: (i) How do the impacts of pruning on the management of shoot blight compare between a vertical-axis orchard with mature trees and a high-density planting with young trees? (ii) Do sanitation and ancillary chemical management have a significant impact on shoot blight control achieved through pruning? (iii) How do a variety of pruning programs, including those preferred by researchers, growers, and extension agents compare in terms of shoot blight management? The impacts of pruning programs were more pronounced in the vertical-axis orchard in terms of reducing infection spread and overall shoot blight incidence. However, in the high-density plantings pruning programs were mostly ineffective and fire blight spread quickly throughout the trees and planting. Overall, the most aggressive pruning programs, which removed tissue of several seasons of growth, had the greatest impact on fire blight in both plantings. In line with the findings of many previous studies, sanitation and chemical management supplementation were not found to be necessarily beneficial.

A short communication regarding the trends and prevalence of H. Pylori in unselected gastric mucosal biopsy samples at a tertiary care hospital in Karachi, Pakistan: a five-year retrospective

A spiral gram-negative bacteria, known as helicobacter pylori, is frequently discovered in the stomach and is linked to a number of clinical disorders. Understanding its prevalence and trends is crucial for both improved clinical outcomes as well as greater epidemiological insight into the region. The current retrospective study was planned to analyse the prevalence and frequency trends of helicobacter pylori in gastric mucosal samples from a Karachi-based tertiary care centre. Data from a 5-year period was analysed. Sampled individuals' age, gender, site of infection and histopathological findings were noted. A decreasing trend in helicobacter pylori infections in biopsy samples was observed. Gender and age showed no significant association (p&gt;0.05), while infection site and histopathological findings exhibited significant correlations (p&lt;0.05). Antrum predominated for all types of gastritis. The study highlighted a declining trend in helicobacter pylori prevalence in Karachi over 5 years. Further multicentre studies with larger samples may provide deeper insights into helicobacter pylori trends in Pakistan. Key Words: Gastritis, Antrum, H. Pylori, Gastric ulcer.

Aminopeptidase-Responsive NIR Photosensitizer for Precision Targeting and Eradication of Pseudomonas aeruginosa Biofilms.

The emergence of resistance in Pseudomonas aeruginosa represents a significant global health challenge, particularly due to the hurdle of effectively penetrating biofilms with antimicrobials. Moreover, the rise of antibiotic-resistant pathogens has driven the urgent need for developing innovative therapeutic approaches to overcome antibiotic resistance. Antibacterial phototherapy strategies have shown great potential for combating pathogens due to their broad-spectrum antimicrobial activity, spatiotemporal controllability, and relatively low rate of resistance emergence. However, due to the lack of bacterial specificity and penetration, photosensitizers cause considerable damage to mammalian cells and normal tissues and are less effective against bacterial biofilms. Herein, we developed a novel dual-targeting antibacterial strategy to construct a near-infrared photosensitizer, Cy-NEO-Leu. Cy-NEO-Leu showed great bacterial targeting affinity, penetrating and accumulating in biofilms. At the site of infection, it was specifically activated by P. aeruginosa aminopeptidase (PaAP), producing Cy-NEO-NH2, which demonstrated outstanding photothermal (PTT) and photodynamic (PDT) properties, with a photothermal conversion efficiency of up to 70.34%. Both in vitro and in vivo results demonstrated that Cy-NEO-Leu significantly reduced the biofilm biomass and bacterial viability in P. aeruginosa biofilms. Moreover, phototherapy with Cy-NEO-Leu further activated the immune system, enhancing therapeutic efficacy and promoting wound healing. RNA-seq analysis revealed that the antibacterial mechanism of Cy-NEO-Leu-mediated phototherapy involves disruption of the transcriptional and translational processes of P. aeruginosa under laser irradiation. Overall, our results present a promising therapeutic approach against P. aeruginosa biofilms and inspire the development of next-generation antimicrobials.