Bacterial Samples Research Articles

The Use of the Taylor Spatial Frame in Treating Tibial Osteomyelitis Following Traumatic Tibial Fracture.

Tibial osteomyelitis can follow open fractures with bacteria colonising the wound and persisting through biofilm and sequestrum formation. The treatment is complex, requiring eradication through debridement before limb reconstruction, for which the Taylor spatial frame (TSF) is one option. This study evaluates patient outcomes after reconstruction and identifies factors associated with post-operative complications. Fifty-one cases of tibial osteomyelitis were treated by the Ilizarov technique from 2015 to 2021 at a major trauma centre. Bacterial samples and treatment factors were assessed. Patient outcomes were complication rates and time to bony union. Complications were expressed as odds-ratios (OR) with 95% confidence intervals. Linear regression was used to assess factors associated with time to union. The mean follow-up was 24.1 months with the mean time to radiological union being 11 months. Post-operative complications were noted in 76.5% of patients with pin-site infections most common (52.9%), followed by fracture malunion (29.4%). Smoking was associated with increased fracture malunion (OR = 4.148, 95% confidence Interval [1.13-15.18], p = 0.031). The time to union was positively associated with complications, age and time to full weight-bearing (FWB). All other measured factors were found not significant. Tibial osteomyelitis is treated reliably by debridement and reconstruction using the Ilizarov technique using a TSF application. The most common complication was pin-site infection. Optimising patients through cessation of smoking and encouraging post-operative weight-bearing can reduce the complication rate and improve time to union. The Ilizarov technique using a TSF can treat significant deformities that result from the management of tibial osteomyelitis. Geetala R, Zhang J, Maghsoudi D, et al. The Use of the Taylor Spatial Frame in Treating Tibial Osteomyelitis Following Traumatic Tibial Fracture. Strategies Trauma Limb Reconstr 2024;19(1):32-35.

Development and evaluation of a multi-target droplet digital PCR assay for highly sensitive and specific detection of Yersinia pestis.

Plague, caused by the bacterium Yersinia pestis, is a zoonotic disease that poses considerable threats to human health. Nucleic acid tests are crucial for plague surveillance and the rapid detection of Y. pestis. However, inhibitors in complex samples such as soil and animal tissues often hamper nucleic acid detection, leading to a reduced rate of identifying low concentrations of Y. pestis. To address this challenge, we developed a sensitive and specific droplet digital polymerase chain reaction (ddPCR) assay for detecting Y. pestis DNA from soil and animal tissue samples. Three genes (ypo2088, caf1, and pla) from Y. pestis were used to develop a multi-target ddPCR assay. The limits of detection (LoD), reproducibility, and specificity were assessed for bacterial genomic DNA samples. The ability of the assay to detect low concentrations of Y. pestis DNA from simulated soil and mouse liver tissue samples was respectively evaluated and compared with that of quantitative real-time PCR (qPCR). The results showed that the ddPCR LoDs ranged from 6.2 to 15.4 copies/reaction for the target genes, with good reproducibility and high specificity for Y. pestis. By testing 130 soil and mouse liver tissue samples spiked with Y. pestis, the ddPCR assay exhibited a better sensitivity than that of the qPCR assay used in the study, with LoDs of 102 colony forming units (CFU)/100 mg soil and 103 CFU/20 mg liver. Moreover, the assay presented good quantitative linearity (R2 = 0.99) for Y. pestis at 103-106 CFU/sample for soil and liver samples. The ddPCR assay presented good performance for detecting Y. pestis DNA from soil and mouse tissue samples, showing great potential for improving the detection rate of low concentrations of Y. pestis in plague surveillance and facilitating the early diagnosis of plague cases.

Detection of florfenicol resistance in opportunistic Acinetobacter spp. infections in rural Thailand.

Florfenicol (Ff) is an antimicrobial agent belonging to the class amphenicol used for the treatment of bacterial infections in livestock, poultry, and aquaculture (animal farming). It inhibits protein synthesis. Ff is an analog of chloramphenicol, an amphenicol compound on the WHO essential medicine list that is used for the treatment of human infections. Due to the extensive usage of Ff in animal farming, zoonotic pathogens have developed resistance to this antimicrobial agent. There are numerous reports of resistance genes from organisms infecting or colonizing animals found in human pathogens, suggesting a possible exchange of genetic materials. One of these genes is floR, a gene that encodes for an efflux pump that removes Ff from bacterial cells, conferring resistance against amphenicol, and is often associated with mobile genetic elements and other resistant determinants. In this study, we analyzed bacterial isolates recovered in rural Thailand from patients and environmental samples collected for disease monitoring. Whole genome sequencing was carried out for all the samples collected. Speciation and genome annotation was performed revealing the presence of the floR gene in the bacterial genome. The minimum inhibitory concentration (MIC) was determined for Ff and chloramphenicol. Chromosomal and phylogenetic analyses were performed to investigate the acquisition pattern of the floR gene. The presence of a conserved floR gene in unrelated Acinetobacter spp. isolated from human bacterial infections and environmental samples was observed, suggesting multiple and independent inter-species genetic exchange of drug-resistant determinants. The floR was found to be in the variable region containing various mobile genetic elements and other antibiotic resistance determinants; however, no evidence of HGT could be found. The floR gene identified in this study is chromosomal for all isolates. The study highlights a plausible impact of antimicrobials used in veterinary settings on human health. Ff shares cross-resistance with chloramphenicol, which is still in use in several countries. Furthermore, by selecting for floR-resistance genes, we may be selecting for and facilitating the zoonotic and reverse zoonotic exchange of other flanking resistance markers between human and animal pathogens or commensals with detrimental public health consequences.

Oral bacteria may affect conjunctival microorganisms in brachycephalic dogs: a preliminary study.

To evaluate the prevalence of oral bacteria in the conjunctiva of brachycephalic and nonbrachycephalic dogs. 12 brachycephalic (9.58 ± 3.55 years) and 12 nonbrachycephalic (8.33 ± 4.92 years) dogs without systemic disease, regardless of breed and sex, were included in the study, and half of the dogs in each group had periodontitis. This prospective study investigated clinical data including craniofacial ratio, ophthalmic examination results, and periodontal status of the included dogs. Bacterial samples were collected by swabbing the oral mucosa and conjunctival surfaces. The presence and quantity of bacteria were analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, 16S rRNA sequencing analysis, and the 10-fold dilution method. Statistical analyses were performed to assess correlations and factors influencing the presence of oral bacteria in the conjunctiva. The most common bacteria in the conjunctival flora in both groups were Micrococcus luteus, Corynebacterium spp, and Staphylococcus spp. The prevalence of oral bacteria on the conjunctival surface was 33%, with a significantly higher incidence in brachycephalic dogs (P = .027). Oral bacteria detected in the conjunctiva were predominantly Frederiksenia canicola, Neisseria spp, and Moraxella spp. Multiple regression analysis identified age, craniofacial ratio, and gingival index as factors influencing the presence of oral bacteria in the conjunctival flora. Oral resident bacteria have often been isolated from severe infectious corneal ulcers. This study provided evidence that brachycephalic dogs may require dental prophylaxis to reduce their oral bacterial load and that the association of oral bacteria in ocular diseases should be considered.

Discriminant analysis of a mixture of pathogenic bacteria into different types and proportions by surface-enhanced Raman scattering spectroscopy combined with chemometric methods

Accurate identification and discrimination of bacteria is crucial for ensuring food safety and reducing pathogenic infections. This study presents a novel approach that combines surface-enhanced Raman scattering spectroscopy (SERS) with chemometric methods for discriminant analysis of a mixture of pathogenic bacteria into different types and proportions. Au@Ag@SiO2 composite nanomaterials were employed as the SERS substrate to collect Raman spectra of multiple pathogenic bacteria. Partial least squares discriminant analysis (PLS-DA) and orthogonal partial least squares discriminant analysis (OPLS-DA) methods were combined with standard normal variate (SNV) to discriminate the different species of mixed bacteria and the multiple proportion mixed bacterial samples, respectively. The results showed that SNV-PLS-DA had good classification performance in the discriminant analysis of different species of mixed bacteria, with an accuracy of 92% for the external test set. Furthermore, both SNV-PLS-DA and SNV-OPLS-DA models exhibited excellent classification performance in the discrimination of multiple pathogenic bacteria at different mixing proportions, achieving 100% accuracy in the external test set, but except for mixed samples of Escherichia coli and Salmonella typhimurium. Our method demonstrates the accurate capability of the SERS platform combined with chemometric methods in the discriminant analysis of multiple pathogenic bacteria at different species and mixing proportions, which provides novel insights for the synchronous analysis of multiple pathogenic bacteria.

Preliminary study on the diversity and quantity analysis of oral bacteria according to the sampling methods

Objectives: Oral bacterial samples included subgingival, supragingival, and saliva plaques. As the diversity and number of microorganisms deffer depending on the area of the oral cavity and the method used, an appropriate and reliable collection method is important. The present study investigated oral bacterial sampling methods. Methods: Supragingival dental plaque was collected from the buccal and lingual tooth surfaces of study participants using sterilized cotton swabs. Plaques were collected from the subgingival area using a sterilized curette. Bacterial genomic DNA was extracted using MagNA Pure 96 DNA and Viral NA low-volume kits. Real-time polymerase chain reaction (PCR) was performed using the PowerCheck™ Periodontitis Pathogens Multiplex Real-time PCR kit. Results: Aggregatibacter actinomycetemcomitans, Prevotella intermedia, and Fusobacterium nucleatum of the orange complex were not observed in the subgingival biofilms of all study participants. For Porphyromonas. gingivalis, a significant correlation was observed between supragingival, subgingival, and total tooth surface biofilms. Compared to the supragingival and subgingival biofilmss, total tooth surface biofilm exhibited the highest bacterial count when the inswabbing method was used. Conclusions: Based on these findings, the supragingival swab method is recommended for oral bacterial research.

Characterization of Escherichia coli pathogenicity and drug resistance in yolk peritonitis

Yolk Peritonitis can lead to a rapid decline in egg production, which seriously affects the health of laying hens and the profitability of chicken farms. Escherichia coli (E. coli) is the most common cause of yolk peritonitis in laying hens. In this study, bacterial samples were collected from the ovaries and fallopian tubes of laying hens with suspected yolk peritonitis from a laying farm in Jiangsu Province, and their pathogenicity and drug resistance were investigated. Initially, morphological and biochemical detection methods were employed to isolate and identify the pathogenic bacteria. The results showed that a total of 16 strains of E. coli were isolated from laying hens with yolk peritonitis. Subsequently, the drug resistance and pathogenicity of a randomly selected E. coli strain were analyzed and predicted by genome sequencing technology, and the drug resistance of E. coli was verified by drug sensitivity test and PCR. Finally, the virulence was verified by infection experiment in mice. The study revealed that the egg-yolk peritonitis in laying hens was caused by E. coli infection, and the genome sequencing analysis revealed that the bacteria had multidrug resistance and high virulence. The drug susceptibility testing indicates that E. coli exhibited resistance to aminoglycosides, β-lactam, macrolides, fluoroquinolones, and sulfonamides. In this study, resistance genes including KdpE, aadA5, APH(3 ")-ID, APH(6)-ID, and TEM-1 were identified, and their expression levels varied across different stages of bacterial growth. The results of virulence analysis indicated a mortality rate of 50% in mice infected with E. coli at a concentration of 2.985 × 107 CFU/mL. E. coli infection resulted in damage to various tissues and organs in mice, with the intestinal tissue structure being the most severely affected. This study provides a reference for the study of drug resistance mechanisms in E. coli and provides valuable insights into the selection of drugs for the treatment of vitelline peritonitis.

A Label-Free Droplet Sorting Platform Integrating Dielectrophoretic Separation for Estimating Bacterial Antimicrobial Resistance.

Antimicrobial resistance (AMR) has become a crucial global health issue. Antibiotic-resistant bacteria can survive after antibiotic treatments, lowering drug efficacy and increasing lethal risks. A microfluidic water-in-oil emulsion droplet system can entrap microorganisms and antibiotics within the tiny bioreactor, separate from the surroundings, enabling independent assays that can be performed in a high-throughput manner. This study presents the development of a label-free dielectrophoresis (DEP)-based microfluidic platform to sort droplets that co-encapsulate Escherichia coli (E. coli) and ampicillin (Amp) and droplets that co-encapsulate Amp-resistant (AmpR) E. coli with Amp only based on the conductivity-dependent DEP force (FDEP) without the assistance of optical analyses. The 9.4% low conductivity (LC) Luria-Bertani (LB) broth diluted with 170 mM mannitol can maintain E. coli and AmpR E. coli growth for 3 h and allow Amp to kill almost all E. coli, which can significantly increase the LCLB conductivity by about 100 μS/cm. Therefore, the AmpR E. coli/9.4%LCLB/Amp where no cells are killed and the E. coli/9.4%LCLB/Amp-containing droplets where most of the cells are killed can be sorted based on this conductivity difference at an applied electric field of 2 MHz and 100 Vpp that generates positive FDEP. Moreover, the sorting ratio significantly decreased to about 50% when the population of AmpR E. coli was equal to or higher than 50% in droplets. The conductivity-dependent DEP-based sorting platform exhibits promising potential to probe the ratio of AmpR E. coli in an unknown bacterial sample by using the sorting ratio as an index.

Paper-based fluorescence sensor array with functionalized carbon quantum dots for bacterial discrimination using a machine learning algorithm

The rapid discrimination of bacteria is currently an emerging trend in the fields of food safety, medical detection, and environmental observation. Traditional methods often require lengthy culturing processes, specialized analytical equipment, and bacterial recognition receptors. In response to this need, we have developed a paper-based fluorescence sensor array platform for identifying different bacteria. The sensor array is based on three unique carbon quantum dots (CQDs) as sensing units, each modified with a different antibiotic (polymyxin B, ampicillin, and gentamicin). These antibiotic-modified CQDs can aggregate on the bacterial surface, triggering aggregation-induced fluorescence quenching. The sensor array exhibits varying fluorescent responses to different bacterial species. To achieve low-cost and portable detection, CQDs were formulated into fluorescent ink and used with an inkjet printer to manufacture paper-based sensor arrays. A smartphone was used to collect the responses generated by the bacteria and platform. Diverse machine learning algorithms were utilized to discriminate bacterial types. Our findings showcase the platform's remarkable capability to differentiate among five bacterial strains, within a detection range spanning from 1.0 × 103 CFU/mL to 1.0 × 107 CFU/mL. Its practicality is further validated through the accurate identification of blind bacterial samples. With its cost-effectiveness, ease of fabrication, and high degree of integration, this platform holds significant promise for on-site detection of diverse bacteria.Graphical abstract

Transcriptomic features of programmed and inflammatory cell death in gingival tissues.

This study used an experimental periodontitis model to detail the gingival transcriptome related to cell death processes of pyroptosis, necroptosis, ferroptosis, and cuproptosis. Healthy Macaca mulatta primates stratified by age, ≤3 years (young), 7-12 years (adolescent), 12-15 years (adult), and 17-23 years (aged), provided gingival tissue biopsies for microarray analysis focused on 257 genes representative of the four cell death processes and bacterial plaque samples for 16S rRNA gene analysis. Age differences in the profiles of gene expression in healthy tissues were noted for cuproptosis, ferroptosis, necroptosis, and pyroptosis. Major differences were then observed with disease initiation, progression, and resolution also related to the age of the animals. Distinct bacterial families/consortia of species were significantly related to the gene expression differences for the cell death pathways. These results emphasized age-associated differences in the gingival tissue molecular response to changes in the quality and quantity of bacteria accumulating with the disease process reflected in regulated cell death pathways that are both physiological and pathophysiological.

Combining deep learning and droplet microfluidics for rapid and label-free antimicrobial susceptibility testing of colistin

Efficient tools for rapid antibiotic susceptibility testing (AST) are crucial for appropriate use of antibiotics, especially colistin, which is now often considered a last resort therapy with extremely drug resistant Gram-negative bacteria. Here, we developed a rapid, easy and miniaturized colistin susceptibility assay based on microfluidics, which allows for culture and high-throughput analysis of bacterial samples. Specifically, a simple microfluidic platform that can easily be operated was designed to encapsulate bacteria in nanoliter droplets and perform a fast and automated bacterial growth detection in 2 h, using standardized samples. Direct bright-field imaging of compartmentalized samples proved to be a faster and more accurate detection method as compared to fluorescence-based analysis. A deep learning powered approach was implemented for the sensitive detection of the growth of several strains in droplets. The DropDeepL AST method (Droplet and Deep learning-based method for AST) developed here allowed the determination of the colistin susceptibility profiles of 21 fast-growing Enterobacterales (E. coli and K. pneumoniae), including clinical isolates with different resistance mechanisms, showing 100 % categorical agreement with the reference broth microdilution (BMD) method performed simultaneously. Direct AST of bacteria in urine samples on chip also provided accurate results in 2 h, without the need of complex sample preparation procedures. This method can easily be implemented in clinical microbiology laboratories, and has the potential to be adapted to a variety of antibiotics, especially for last-line antibiotics to optimize treatment of patients infected with multi-drug resistant strains.

Marine Microorganisms as Potential Source of Quorum-Sensing Inhibitory Compounds

Antibiotics are extensively utilized globally, and the rate of antibiotic resistance is increasing more rapidly than ever. Since the introduction of antibiotics, the overuse of antibiotics caused selection pressure, and almost all pathogenic bacteria have developed resistance against commonly used antibiotics, which is particularly known as antimicrobial resistance (AMR). It has proven challenging to combat and resolve the issue of microbial resistance. A growing number of microorganisms have developed different resistance mechanisms and turned into "superbugs". The identification of quorum-sensing systems has given researchers a new hope for understanding drug resistance processes. The quorum-sensing system controls a number of cellular functions, including the expression of pathogenic genes, the synthesis of toxins, and the synthesis of extracellular polysaccharides. To targeting QS systems marine bacterial samples were collected by different coastal sites of Gujarat, like Mandvi, Dwarka and Diu. A total of 52 marine isolates were obtained, out of which 16 were associated with various marine macro-organisms like sponges and algae, whereas 36 were free-living. The study has done by screening those marine isolates shown potential to inhibiting the quorum sensing molecule by co culture study against Chromobacter violaceium, followed by growth inhibition assay. The G14 and G82 isolate shows highest degradation of N-acyl homoserine lactone by AHL study. The QSI compounds were extracted using ethyl acetate extraction method. Biofilm inhibition assay with Pseudomonas aeruginosa shows potent inhibitory effect of extract. These results prove that marine microorganism have potential to inhibits quorum sensing and virulence factors regulated by Quorum Sensing phenomenon.

Superficial pyoderma in cats and dogs: A retrospective clinical study

Superficial pyoderma is a common complication of a range of feline and canine skin diseases. The objective of the present study is to retrospectively evaluate bacterial and fungal skin culture samples in superficial pyoderma cases of cats and dogs and to reveal in detail the pathogens and their susceptibility and/or resistance to antimicrobials, as well as demographic data and clinical symptoms of the patients. Medical records of 28 cats and 35 dogs meeting the criteria for inclusion were reviewed. Staphylococcus spp. and Trichophyton species were found to be the most common cultured microorganisms in both cats and dogs. Antimicrobial resistance was determined both in cat and dog samples. As a result, it has been demonstrated that skin culture is particularly important for the management of diagnosis and treatment processes and the regulation of treatment protocols in pyoderma in terms of preventing the increasing antibiotic resistance in recent years and thus protecting both human and animal health.

Trachyspermum copticum aqueous seed extract-derived silver nanoparticles: Exploration of their structural characterization and comparative antibacterial performance against gram-positive and gram-negative bacteria

Abstract In this study, the aqueous seed extract of Trachyspermum copticum was employed to fabricate silver nanoparticles (AgNPs) for their antibacterial performance. The structural characteristics of the phytofabricated AgNPs were investigated using ultraviolet–visible, energy dispersive X-ray, dynamic light scattering, zeta potential, field emission scanning electron microscope, and Fourier transform infrared spectroscopy. Further, the antibacterial effects of AgNPs were evaluated against two standard gram-positive strains of Staphylococcus aureus and Streptococcus pyogenes and two standard gram-negative strains of Escherichia coli and Klebsiella pneumoniae. The findings showed the phytofabrication of spherical-shaped AgNPs with a Z-average diameter of 119.7 nm and the polydispersity index of 0.56. The minimum inhibitory concentration of AgNPs against S. aureus, S. pyogenes, E. coli, and K. pneumoniae strains was 0.25, 1, 0.5, and 0.5 μg·mL−1, respectively. In addition, the minimum bactericidal concentration of these nanoparticles (NPs) against the mentioned strains was 8, 16, 4, and 4 μg·mL−1, respectively. Furthermore, the AgNPs enhanced the generation of reactive oxygen species significantly in all studied bacteria compared to the control (P < 0.05) suggesting an oxidative-associated antibacterial mechanism of AgNPs. Moreover, a dose-dependent cell death was found in all bacterial samples based on flow cytometry analysis. Overall, this study showed a biological approach for the biosynthesis of AgNPs with significant antibacterial effects.

Assessment of Microbial Contamination of Dental Prostheses

Objective: Various dental prostheses, such as crowns and dentures, are crafted in dental laboratories and then applied within the patient's mouth in dental institutions. However, dental workers rarely disinfect them before application. Therefore, we investigated the bacterial contamination of various intraoral prostheses to confirm the importance of infection control. Methods: Bacterial samples were collected from 23 dental prostheses (including six gold crowns, seven zirconia crowns, four porcelain-fused-to-metal crowns, and six dentures) in dental laboratories and dental institutions in Gyeongsangbuk-do, Korea. These samples were inoculated onto 3M Petrifilm for general aerobic bacteria and Staphylococcus aureus, respectively. The colonies that formed after 48 hours of culture were counted. Results: General aerobic bacteria and S. aureus were detected on the majority of dental prostheses, with dentures showing the highest presence (p=0.003). Neither aerobic bacteria nor S. aureus showed statistically significant differences between dental institutions and laboratories. A positive correlation was noted between the denture and the denture in terms of general aerobic bacteria and S. aureus detection (r=0.829, p<0.05). Conclusion: As a result, many bacteria were detected in most dental prostheses. Therefore, there is a need to recognize the risk of crossinfection through dental prosthesis and to establish specific infection control guidelines.

Enhancing Bacteria Classification using Image Processing and Convolutional Neural Network

Bacteria classification plays a vital role in the medical field, facilitating the diagnosis and treatment of various diseases. Traditionally, clinical specialists have relied on conventional techniques for classification, which lack predictive capabilities. Manual classification of bacteria is a laborious and time-consuming task that demands significant human effort. However, advancements in technology have opened possibilities for microorganism classification through the utilization of novel machine learning algorithms. This research explores the integration of Convolutional Neural Networks (CNNs) for the classification of bacterial samples, aiming to revolutionize the traditional manual classification methods in the medical field. The methodology involves three stages: image acquisition, feature extraction, and classification. Employing the Enhanced CNN model, the study demonstrates the effectiveness of deep learning techniques in image classification on a diverse bacterial species. Experimental results reveal superior accuracy compared to existing baseline methods, showcasing the potential of deep learning for efficient and precise bacteria classification. The proposed approach has the potential to alleviates the manual classification burden, saving time, and reducing dependence on human expertise. This research contributes to advancing healthcare practices by enhancing the accuracy and precision of 95% and 93.2% respectively for bacterial classification.

Local Production of World Health Organization Recommended Hand Rub Formulation and Comparison of its Efficacy with a Commercially Available Alcohol-Based Hand Rub

Objective: To produce a World Health Organization (WHO)-recommended hand rub formulation locally and compare its efficacy with a commercially available Alcohol-based Hand Rub (ABHR) - Sterillium. Methods: A non-randomized comparative study was conducted. Sixty healthcare workers were divided into two groups - Group A (WHO-recommended hand rub) and Group B (Sterillium). WHO-recommended hand rub was prepared according to the specified formula. Each participant from study Group A received three ml of WHO-recommended hand rub formulation, and each study Group B participant received three ml of Sterillium. Bacterial samples of each participant (from both hands) were collected before and 0 after using an ABHR solution. Samples were inoculated on the nutrient agar plates and incubated at 37 C for 24 hours. The total number of bacterial colonies grown on plates inoculated before and after ABHR use was counted and identified by standard microbiology techniques and compared between the two groups. The WHO-recommended hand rub and Sterillium were compared and analyzed using differences in proportion. Results: The overall reduction in bacterial growth was comparable for both the hand rubs, with an average load reduction of log 1.5607 for locally produced hand rub solution and an average load reduction of log 1.609 in the case of Sterillium. Conclusion: Both of the handrubs are comparable in efficacy and are effective against all the bacteria isolated from the palms of HCWs (Coagulase Negative Staphylococcus (CoNS), Micrococcus spp., Acinetobacter spp., Bacillus spp., Pseudomonas spp., and Citrobacter), including Methicillin-Sensitive Staphylococcus aureus

Antimicrobial effect of biosynthesis of selenium nanoparticles by Pseudomonas aeruginosa on bacteria isolated from wounds and burns

Abstract: background: In recent decades, the rise of antibiotic resistance as critical global health challenges, necessitating innovative approaches to address these pressing issues. The Center of Disease Control (CDC) estimates that antibiotic resistance is responsible for nearly 5 million deaths in 2019 Objective: This study aims to biosynthesise selenium nanoparticles and the possibility of using as antimicrobal. Methods: Samples were collected from Al-Diwaniyah Teaching Hospital in Al-Diwaniyah Governorate - Iraq , period from April 1, 2023 to June 1, 2023. Bacterial samples were collected from wounds and burns, then they were diagnosed using (Vitek-2 compact system- Biomerieux-France), then all the collected bacterial species were tested to produce selenium nanoparticles and the best bacteria capable of producing them were selected. The synthesis process involved incubation, centrifugation, and purification. The antimicrobal activity of SeNPs was evaluated .Results : Pseudomonas aeruginosa was the predominant pathogen accounting for 30%, followed by Bacillus (24%), Staphylococcus (16%), Escherichia coli (8%), and Candida albicans (12%). Mixed infections are found in 10%. Statistical analysis showed (chi-square = 40.32, p < 0.0001). The bacilli showed high sensitivity to ciprofloxacin (Cip) with a mean diameter of 28 ± 1.02, while amoxicillin (AX), ceftoxime (CTX), doxycycline (DO), and carbenicillin (PY) had no inhibitory effect (0 ± 0). Staphylococci showed sensitivity to ciprofloxacin (18 ± 0.64), amoxicillin (13 ± 0.22), cefatoxime (12 ± 0.4), doxycycline (12 ± 0.4), nitrofuranthone (THAT) (11 ± 1), and neomycin (17.2 ± 1.1). Escherichia coli showed sensitivity to ciprofloxacin (28 ± 1.02) and doxycycline (19 ± 1.4), while Candida albicans showed resistance to all antibiotics tested. Antimicrobial activity was measured using concentrations of 125, 250, 500, and 1000 μg/mL. Results show a concentration-dependent increase in inhibitory effects. Antibiofilm activity ranges from 2 to 1048 μg/mL.Discussion: Lower concentrations (125 µg/ml), minimal inhibition was observed, but as the concentration increased, a clear trend of enhanced inhibition emerged. Notably, at 250 µg/ml, significant growth inhibition was evident, with a concentration-dependent response. The highest concentration (1000 µg/ml) exhibited the most substantial inhibitory effects. The absence of inhibition in the negative control confirms the specificity of nano selenium's impact.conclusion. : The results demonstrate concentration-dependent inhibitory effects of nano selenium on various bacterial species.

Fully integrated and automated centrifugal microfluidic chip for point-of-care multiplexed molecular diagnostics

Public health events caused by pathogens have imposed significant economic and societal burdens. However, conventional methods still face challenges including complex operations, the need for trained operators, and sophisticated instruments. Here, we proposed a fully integrated and automated centrifugal microfluidic chip, also termed IACMC, for point-of-care multiplexed molecular diagnostics by harnessing the advantages of active and passive valves. The IACMC incorporates multiple essential components including a pneumatic balance module for sequential release of multiple reagents, a pneumatic centrifugation-assisted module for on-demand solution release, an on-chip silicon membrane module for nucleic acid extraction, a Coriolis force-mediated fluid switching module, and an amplification module. Numerical simulation and visual validation were employed to iterate and optimize the chip's structure. Upon sample loading, the chip automatically executes the entire process of bacterial sample lysis, nucleic acid capture, elution quantification, and isothermal LAMP amplification. By optimizing crucial parameters including centrifugation speed, direction of rotation, and silicone membrane thickness, the chip achieves exceptional sensitivity (twenty-five Salmonella or forty Escherichia coli) and specificity in detecting Escherichia coli and Salmonella within 40 min. The development of IACMC will drive advancements in centrifugal microfluidics for point-of-care testing and holds potential for broader applications in precision medicine including high-throughput biochemical analysis immune diagnostics, and drug susceptibility testing.

Use of thioglycolate broth as a pre-analytic transport medium in the diagnosis of prosthetic joint infection.

This study aimed to investigate whether adding tissue samples directly into thioglycolate (TG) broth yielded a greater number of anaerobic organisms than freshly sampled tissue in suspected hip and knee prosthetic joint infections (PJIs). Between January 2017 and December 2020, a total of 90 patients (46 males, 44 females; median age: 71.7 years; range, 50.8 and 87.8 years) who underwent revision hip or knee arthroplasty were included. Intraoperative samples were taken, with five placed in TG broth and five in standard containers (PC) with subsequent aerobic and anaerobic culturing conducted. Demographic and baseline data of the patients were recorded. The primary outcome was positive bacterial growth from a PJI specimen inoculated directly into TG broth at the time of collection or standard PJI specimen processing. Secondary outcomes investigated were the presence of Cutibacterium acnes (C. acnes) and the curative success of revision procedure. A total of 900 samples (450 PC and 450 TG) were taken from 90 revision arthroplasty patients (47 knees and 43 hips). There was no statistically significant difference in the number of positive bacterial growth samples between TG broth and standard processing (p=0.742). This was consistent with subgroup analysis analyzing C. acnes (p=0.666). In hip and knee arthroplasty, there is no benefit in substituting or adding TG broth as a culture medium to better identify both general bacterial species and C. acnes infections specifically. However, the use of TG may be useful in confirming a true positive result for infection.