-
Photodiagnosis and Photodynamic Therapy Feb 2024The aim of this study was to investigate the effects of antimicrobial photodynamic therapy (PDT) using 635 nm diode laser irradiation with an energy density of 6 to 30...
Comparative study of the effect of different exposure parameters of 635nm diode laser and toluidine blue O in eliminating Aggregatibacter actinomycetemcomitans biofilm from titanium implant surfaces.
BACKGROUND
The aim of this study was to investigate the effects of antimicrobial photodynamic therapy (PDT) using 635 nm diode laser irradiation with an energy density of 6 to 30 J/cm and toluidine blue O (TBO) as a photosensitizer on the viability of Aggregatibacter actinomycetemcomitans attached to the surface of titanium implants.
MATERIALS AND METHODS
Titanium implants contaminated with A. actinomycetemcomitans were treated with TBO alone or in combination with different exposure parameters (light doses of 6 - 30 J/cm at 635 nm) and 0.2 % chlorhexidine (CHX). After treatment, colony forming units (CFUs)/ml were determined to assess PDT efficacy. The structure of the biofilm of A. actinomycetemcomitans was analyzed by field emission scanning electron microscopy (FESEM).
RESULTS
Under optimal conditions, the colony count was reduced by ∼90 %. Treatment with CHX was somewhat more effective (colony formation was reduced by ∼95 %), but this agent has adverse effects that can be avoided with PDT.
CONCLUSION
This study confirms the efficacy of PDT against A. actinomycetemcomitans depending on the light dose. Treatment with TBO + 635 nm diode laser has an effect that may be equivalent to that of CHX, but perhaps with fewer adverse effects.
Topics: Aggregatibacter actinomycetemcomitans; Titanium; Tolonium Chloride; Lasers, Semiconductor; Photosensitizing Agents; Photochemotherapy; Biofilms; Chlorhexidine
PubMed: 38346465
DOI: 10.1016/j.pdpdt.2024.104012 -
BMC Veterinary Research Feb 2024Respiratory tract diseases cause significant economic loss in beef cattle. This study aimed to determine whether the application of hyperimmune serum (HS) containing...
BACKGROUND
Respiratory tract diseases cause significant economic loss in beef cattle. This study aimed to determine whether the application of hyperimmune serum (HS) containing antibodies against selected antigens of Gram-negative bacteria would improve the health and growth of different breeds of beef calves kept on three farms. Two recombinant protein antigens (Histophilus somni rHsp60 and rOMP40) were used to immunize four cows to produce HS. Eighty seven beef calves (Charolaise n = 36, Limousine n = 34, and crossbreed n = 17) were included into study. One hundred milliliters of serum were administered subcutaneously to 43 beef calves (Charolaise n = 18, Limousine n = 17, and crossbreed n = 8) twice, between 1 and 5 and 21-28 days of life. Calves were examined three times, and blood samples were taken to evaluate immunoglobulin M, G, and G2, fibrinogen, serum amyloid A, and haptoglobin concentrations and reactivity of these Ig classes of antibodies against H. somni rHsp60 and rOMP40. Average daily weight gain during the first month and until weaning was calculated.
RESULTS
HS showed higher (p ≤ 0.05) reactivity in calf sera against H. somni rHsp60 and OMP40 in IgG and IgG. In experimental calves, compared to control calves, the reactivity of IgG against rOMP40 in the second sampling was higher in Limousine calves (p ≤ 0.001) and in the other two herds (p ≤ 0.05). Serum IgG antibody activity against H. somni rHsp60 in the second sampling was higher in experimental calves than in control calves in charolaise (p ≤ 0.05) and limousine (p ≤ 0.001) herds. The reactivity of IgG against rOMP40 in the second sampling of experimental calves was higher in herds with Charolaise and Limousine calves (p ≤ 0.001) and in crossbred calves (p ≤ 0.05). In the third sampling, serum IgG antibody reactivity against rOMP40 in Limousine calves was higher (p ≤ 0.05) in the experimental group. Among the other evaluated parameters, only SAA in the second sampling in the herd with Charolaise calves and heart rate in the herd with Limousine calves were significantly higher in the control calves (p ≤ 0.05).
CONCLUSION
The application of HS to calves in all herds had an impact on specific reactivity in IgG and IgG classes against H. somni rOMP40 and rHsp60, antigens which were used for serum production.
Topics: Female; Cattle; Animals; Gram-Negative Bacteria; Recombinant Proteins; Immunoglobulin M; Pasteurellaceae; Immunoglobulin G; Cattle Diseases
PubMed: 38341558
DOI: 10.1186/s12917-024-03895-2 -
Photodiagnosis and Photodynamic Therapy Feb 2024This study aimed to assess the effect of antibacterial photodynamic therapy (aPDT) with chitosan nanoparticles on Aggregatibacter actinomycetemcomitans (A....
BACKGROUND
This study aimed to assess the effect of antibacterial photodynamic therapy (aPDT) with chitosan nanoparticles on Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) in the culture medium.
MATERIALS AND METHODS
In this in vitro, experimental study, chitosan nanoparticles (CHNPs) containing indocyanine green (ICG) were first synthesized and characterized. A. actinomycetemcomitans was cultured on trypticase soy agar. The culture media containing A. actinomycetemcomitans were randomly subjected to the following six decontamination protocols: negative control subjected to sterile phosphate buffered saline (PBS) for 5 min, positive control exposed to 0.2 % chlorhexidine (CHX) for 5 min, exposure to 0.25 mg/mL ICG in the dark at 37 °C for 5 min, aPDT with 0.25 mg/mL ICG and diode laser (808 nm, 250 mW, 14.94 J/cm, 30 s, 1 mm distance, 8 mm tip diameter), exposure to CHNPs containing 0.25 mg/mL ICG in the dark at 37 °C for 5 min, and aPDT with CHNPs containing 0.25 mg/mL ICG and diode laser. The number of colonies was counted, and analyzed by one-way ANOVA and Tamhane test (alpha=0.050).
RESULTS
Antimicrobial PDT with CHNPs, and CHX groups comparably showed the highest decontamination efficacy (P = 0.000).
CONCLUSION
The results showed optimal efficacy of aPDT with CHNPs containing 0.25 mg/mL ICG and 808 nm diode laser for reduction of A. actinomycetemcomitans colony count. Thus, aPDT appears to be as effective as CHX, but with fewer adverse effects.
Topics: Aggregatibacter actinomycetemcomitans; Chitosan; Photochemotherapy; Photosensitizing Agents; Anti-Bacterial Agents; Chlorhexidine; Culture Media; Indocyanine Green; Nanoparticles
PubMed: 38336150
DOI: 10.1016/j.pdpdt.2024.103996 -
Applied and Environmental Microbiology Mar 2024Control measures are being introduced globally to reduce the prevalence of antibiotic resistance (ABR) in bacteria on farms. However, little is known about the current...
Genomic epidemiology of third-generation cephalosporin-resistant from Argentinian pig and dairy farms reveals animal-specific patterns of co-resistance and resistance mechanisms.
UNLABELLED
Control measures are being introduced globally to reduce the prevalence of antibiotic resistance (ABR) in bacteria on farms. However, little is known about the current prevalence and molecular ecology of ABR in bacterial species with the potential to be key opportunistic human pathogens, such as on South American farms. Working with 30 dairy cattle farms and 40 pig farms across two provinces in central-eastern Argentina, we report a comprehensive genomic analysis of third-generation cephalosporin-resistant (3GC-R) , which were recovered from 34.8% (cattle) and 47.8% (pigs) of samples from fecally contaminated sites. Phylogenetic analysis revealed substantial diversity suggestive of long-term horizontal and vertical transmission of 3GC-R mechanisms. CTX-M-15 and CTX-M-2 were more often produced by isolates from dairy farms, while CTX-M-8 and CMY-2 and co-carriage of amoxicillin/clavulanate resistance and florfenicol resistance were more common in isolates from pig farms. This suggests different selective pressures for antibiotic use in these two animal types. We identified the β-lactamase gene , which has previously only been reported in the family , in 3GC-R was found alongside a novel florfenicol resistance gene, , also mobilized from a pig pathogen as part of a new composite transposon. As the first comprehensive genomic survey of 3GC-R in Argentina, these data set a baseline from which to measure the effects of interventions aimed at reducing on-farm ABR and provide an opportunity to investigate the zoonotic transmission of resistant bacteria in this region.
IMPORTANCE
Little is known about the ecology of critically important antibiotic resistance among bacteria with the potential to be opportunistic human pathogens (e.g., ) on South American farms. By studying 70 pig and dairy cattle farms in central-eastern Argentina, we identified that third-generation cephalosporin resistance (3GC-R) in was mediated by mechanisms seen more often in certain species and that 3GC-R pig were more likely to be co-resistant to florfenicol and amoxicillin/clavulanate. This suggests that on-farm antibiotic usage is key to selecting the types of present on these farms. 3GC-R and 3GC-R plasmids were diverse, suggestive of long-term circulation in this region. We identified the mobilization of the resistance gene from pig pathogens into on a novel mobile genetic element, which shows the importance of surveying poorly studied regions for antibiotic resistance that might impact human health.
Topics: Animals; Humans; Swine; Cattle; Escherichia coli; Farms; Cephalosporins; Escherichia coli Infections; Phylogeny; Anti-Bacterial Agents; beta-Lactamases; Genomics; Amoxicillin; Clavulanic Acid; Thiamphenicol
PubMed: 38334306
DOI: 10.1128/aem.01791-23 -
PloS One 2024Mannheimia haemolytica is the principal agent contributing to bovine respiratory disease and can form biofilms with increased resistance to antibiotic treatment and host...
Mannheimia haemolytica is the principal agent contributing to bovine respiratory disease and can form biofilms with increased resistance to antibiotic treatment and host immune defenses. To investigate the molecular mechanisms underlying M. haemolytica biofilm formation, transcriptomic analyses were performed with mRNAs sequenced from planktonic and biofilm cultures of pathogenic serotypes 1 (St 1; strain D153) and St 6 (strain D174), and St 2 (strain D35). The three M. haemolytica serotypes were cultured in two different media, Roswell Park Memorial Institute (RPMI) 1640 and brain heart infusion (BHI) to form the biofilms. Transcriptomic analyses revealed that the functions of the differentially expressed genes (DEGs) in biofilm associated cells were not significantly affected by the two media. A total of 476 to 662 DEGs were identified between biofilm associated cells and planktonic cells cultured under BHI medium. Functional analysis of the DEGs indicated that those genes were significantly enriched in translation and many biosynthetic processes. There were 234 DEGs identified in St 1 and 6, but not in St 2. The functions of the DEGs included structural constituents of ribosomes, transmembrane proton transportation, proton channels, and proton-transporting ATP synthase. Potentially, some of the DEGs identified in this study provide insight into the design of new M. haemolytica vaccine candidates.
Topics: Animals; Cattle; Mannheimia haemolytica; Plankton; Protons; Biofilms; Cattle Diseases; Gene Expression Profiling
PubMed: 38329985
DOI: 10.1371/journal.pone.0297692 -
Human Vaccines & Immunotherapeutics Dec 2024DTaP5-HBV-IPV-Hib (Vaxelis®) is a hexavalent combination vaccine (HV) indicated in infants and toddlers for the prevention of diphtheria, tetanus, pertussis, hepatitis...
A phase 4, open-label study to evaluate the safety and immunogenicity of DTaP5-HBV-IPV-Hib in children previously vaccinated with DTaP2-HBV-IPV-Hib or DTaP5-HBV-IPV-Hib (V419-016).
DTaP5-HBV-IPV-Hib (Vaxelis®) is a hexavalent combination vaccine (HV) indicated in infants and toddlers for the prevention of diphtheria, tetanus, pertussis, hepatitis B, poliomyelitis, and invasive disease due to type b. Switching between HVs during the childhood vaccination series is sometimes necessary due to, for example, vaccine availability, health-care provider preference, and/or tender awards. The purpose of this study was to describe the safety, tolerability, and immunogenicity of a booster dose of Vaxelis® in participants who previously received a primary infant series of either DTaP2-HBV-IPV-Hib (Hexyon®) or Vaxelis®. Healthy participants approximately 11-13 months of age who previously received a two-dose primary series of Hexyon® (HHV group) or Vaxelis® (VVV group) all received a Vaxelis® booster dose. Immunogenicity was evaluated by measuring antibody levels to individual vaccine antigens approximately 30 days following booster vaccination. Safety was evaluated as the proportion of participants with adverse events (AEs). The proportions of participants with antibody-specific responses for antigens contained in both Vaxelis® and Hexyon® at 30 days post-toddler-booster vaccination with Vaxelis® were comparable between groups, and higher in the VVV group for Vaxelis® antigens PRN and FIM2/3. The overall proportions of participants with AEs were generally comparable between groups. Following a booster dose of Vaxelis®, immune responses were comparable between groups for all shared antigens, and higher in the VVV group for antigens found only in Vaxelis®. The booster was well tolerated in both groups. These data support the use of Vaxelis® as a booster in mixed HV regimens.
Topics: Humans; Infant; Haemophilus influenzae type b; Hepatitis B virus; Diphtheria-Tetanus-Pertussis Vaccine; Vaccines, Combined; Tetanus; Diphtheria; Whooping Cough; Poliovirus Vaccine, Inactivated; Hepatitis B Vaccines; Haemophilus Vaccines; Immunization Schedule; Antibodies, Bacterial
PubMed: 38327239
DOI: 10.1080/21645515.2024.2310900 -
European Review For Medical and... Jan 2024Osteoporosis (OP) is closely associated with gut microbiota (GM), yet the nature of their causal relationship remains elusive. Therefore, this study aims to reverse...
OBJECTIVE
Osteoporosis (OP) is closely associated with gut microbiota (GM), yet the nature of their causal relationship remains elusive. Therefore, this study aims to reverse causality between GM and OP by using population cohorts and two-sample MR (TSMR) analysis.
MATERIALS AND METHODS
In this study, we conducted an extensive genome-wide association study (GWAS) using publicly accessible summary statistics data for GM and OP. Employing rigorous criteria (p < 1*e-5), we identified independent genetic loci that exhibited significant associations with GM relative abundances as instrumental variables (IVs). A causal evaluation was primarily carried out using the inverse variance-weighted (IVW) method, supplemented by additional analyses such as MR-Egger, weighted median, simple mode, and weighted mode.
RESULTS
We unveiled that increased abundances of the family Pasteurellaceae, order Pasteurellales, and genus Ruminococcaceae UCG004 were linked to an increased risk of OP. Conversely, the family Oxalobacteraceae, unknown family id.1000006161, genus Lachnospiraceae NK4A136 group, unknown genus id.1000006162, and order NB1n were associated with a reduced risk of OP. To ensure the reliability of our findings, we conducted quality assessments through Cochrane's Q test and a leave-one-out analysis. Furthermore, the stability and consistency of the results were confirmed by the MR-Egger intercept test, Mendelian randomization pleiotropy residual sum and outlier (MR-PRESSO) global test, and sensitivity analysis (p > 0.05). Our study reveals the causal relationships between 211 GM taxa and OP, pinpointing specific GM taxa associated with the risk of OP. This research sheds light on the genetic mechanisms that underlie GM-mediated OP and opens up promising avenues for identifying valuable biomarkers and potential therapeutic targets in future OP research.
CONCLUSIONS
This study establishes a substantial GM-OP link with specific taxa being identified, offering biomarkers for early detection, tailored interventions, and improved patient education. These findings enhance OP diagnosis, prevention, and treatment, promising more effective, individualized care and inspiring future research.
Topics: Humans; Gastrointestinal Microbiome; Genome-Wide Association Study; Mendelian Randomization Analysis; Reproducibility of Results; Osteoporosis; Biomarkers
PubMed: 38305631
DOI: 10.26355/eurrev_202401_35052 -
Veterinary Microbiology Mar 2024Gallibacterium anatis is a Gram-negative bacterium found in the respiratory and genital tracts of various animals, primarily poultry. Its association with septicemia and...
Gallibacterium anatis is a Gram-negative bacterium found in the respiratory and genital tracts of various animals, primarily poultry. Its association with septicemia and high mortality in poultry, along with the rise in multidrug-resistant strains, has amplified concerns. Recent research uncovered significant variability in antibiotic resistance profiles among G. anatis isolates from different Austrian flocks, and even between different organs within the same bird. In response, in the present study 60 of these isolates were sequenced and a combination of comparative genomics and genome-wide association study (GWAS) analysis was applied to understand the genetic variability of G. anatis across flocks and organs and to identify genes related to antibiotic resistance. The results showed that each flock harbored one or two strains of G. anatis with only a few strains shared between flocks, demonstrating a great variability among flocks. We identified genes associated with resistance to nalidixic acid, trimethoprim, cefoxitin, tetracycline, ampicillin and sulfamethoxazole. Our findings revealed that G. anatis may develop antibiotic resistance through two mechanisms: single-nucleotide mutations and the presence of specific genes that confer resistance. Unexpectedly, some tetracycline-resistant isolates lacked all known tetracycline-associated genes, suggesting the involvement of novel mechanisms of tetracycline resistance that require additional exploration. Furthermore, our functional annotation of resistance genes highlighted the citric acid cycle pathway as a potential key modulator of antibiotic resistance in G. anatis. In summary, this study describes the first application of GWAS analysis to G. anatis and provides new insights into the acquisition of multidrug resistance in this important avian pathogen.
Topics: Animals; Anti-Bacterial Agents; Genome-Wide Association Study; Chickens; Pasteurellaceae; Tetracycline; Poultry; Tetracycline Resistance; Genomics; Poultry Diseases
PubMed: 38301451
DOI: 10.1016/j.vetmic.2024.109995 -
International Journal of Molecular... Jan 2024Respiratory diseases in ruminants are a main cause of economic losses to farmers worldwide. Approximately 25% of ruminants experience at least one episode of respiratory...
Respiratory diseases in ruminants are a main cause of economic losses to farmers worldwide. Approximately 25% of ruminants experience at least one episode of respiratory disease during the first year of life. is the main etiological bacterial agent in the ruminant respiratory disease complex. can secrete several virulence factors, such as leukotoxin, lipopolysaccharide, and proteases, that can be targeted to treat infections. At present, little information has been reported on the secretion of A2 proteases and their host protein targets. Here, we obtained evidence that A2 proteases promote the degradation of hemoglobin, holo-lactoferrin, albumin, and fibrinogen. Additionally, we performed biochemical characterization for a specific 110 kDa Zn-dependent metalloprotease (110-Mh metalloprotease). This metalloprotease was purified through ion exchange chromatography and characterized using denaturing and chaotropic agents and through zymography assays. Furthermore, mass spectrometry identification and 3D modeling were performed. Then, antibodies against the 110 kDa-Mh metalloprotease were produced, which achieved great inhibition of proteolytic activity. Finally, the antibodies were used to perform immunohistochemical tests on postmortem lung samples from sheep with suggestive histology data of pneumonic mannheimiosis. Taken together, our results strongly suggest that the 110-Mh metalloprotease participates as a virulence mechanism that promotes damage to host tissues.
Topics: Cattle; Sheep; Animals; Mannheimia haemolytica; Pasteurellosis, Pneumonic; Metalloproteases; Peptide Hydrolases; Ruminants; Collagenases; Zinc; Sheep Diseases
PubMed: 38279292
DOI: 10.3390/ijms25021289 -
Frontiers in Cellular and Infection... 2023, the causative agent of porcine pleuropneumonia, poses a significant threat to global swine populations due to its high prevalence, mortality rates, and substantial...
INTRODUCTION
, the causative agent of porcine pleuropneumonia, poses a significant threat to global swine populations due to its high prevalence, mortality rates, and substantial economic ramifications. Understanding the pathogen's defense mechanisms against host-produced reactive oxygen species is crucial for its survival, with OxyR, a conserved bacterial transcription factor, being pivotal in oxidative stress response.
METHODS
This study investigated the presence and role of OxyR in serovar 1-12 reference strains. Transcriptomic analysis was conducted on an oxyR disruption mutant to delineate the biological activities influenced by OxyR. Additionally, specific assays were employed to assess urease activity, catalase expression, ApxI toxin secretion, as well as adhesion and invasion abilities of the oxyR disruption mutant on porcine 3D4/21 and PT cells. A mice challenge experiment was also conducted to evaluate the impact of oxyR inactivation on virulence.
RESULTS
OxyR was identified as a conserved regulator present in serovar 1-12 reference strains. Transcriptomic analysis revealed the involvement of OxyR in multiple biological activities. The oxyR disruption resulted in decreased urease activity, elevated catalase expression, enhanced ApxI toxin secretion-attributed to OxyR binding to the apxIBD promoter-and reduced adhesion and invasion abilities on porcine cells. Furthermore, inactivation of oxyR reduced the virulence of in a mice challenge experiment.
DISCUSSION
The findings highlight the pivotal role of OxyR in influencing the virulence mechanisms of . The observed effects on various biological activities underscore OxyR as an essential factor contributing to the pathogenicity of this bacterium.
Topics: Animals; Mice; Swine; Actinobacillus pleuropneumoniae; Catalase; Virulence; Urease; Oxidative Stress
PubMed: 38268788
DOI: 10.3389/fcimb.2023.1324760