Clinical Isolates Of Bacteria Research Articles

Phytochemical screening of multiple Turmeric (Curcuma longa L.) extracts against multidrug resistant bacteria

Turmeric, a naturally occurring kitchen spice, possesses a wide range of medicinal properties. It has been reported to exhibit analgesic, anti-inflammatory, anti-bacterial, antifungal, antioxidant and wound healing properties. Yet, a detailed investigation is required for its screening against clinical isolates of multidrug resistant bacteria, so that it could be used as, cost effective, indigenous and readily available kitchen spice in crude form for the treatment of these bacterial infections at home. In current study, three fractions of ethyl acetate extracts of turmeric were screened against four multidrug resistant bacterial strains. Disc diffusion method was used to perform antibacterial activity and by calculation the Minimum Inhibitory Concentration (MIC). It was confirmed that all bacterial strains were highly sensitive towards all turmeric fractions. GCMS analysis of various fractions exhibited the presence of various flavonoids and polyphenols, their presence was further ascertained by chemical tests. It has been proposed that the synergistic effect of curcumin as well phenolics, crude extracts of turmeric showed promising antibacterial potential against multidrug resistant bacteria.Turmeric, a naturally occurring kitchen spice, possesses a wide range of medicinal properties. It has been reported to exhibit analgesic, anti-inflammatory, anti-bacterial, antifungal, antioxidant and wound healing properties. Yet, a detailed investigation is required for its screening against clinical isolates of multidrug resistant bacteria, so that it could be used as, cost effective, indigenous and readily available kitchen spice in crude form for the treatment of these bacterial infections at home. In current study, three fractions of ethyl acetate extracts of turmeric were screened against four multidrug resistant bacterial strains. Disc diffusion method was used to perform antibacterial activity and by calculation the Minimum Inhibitory Concentration (MIC). It was confirmed that all bacterial strains were highly sensitive towards all turmeric fractions. GCMS analysis of various fractions exhibited the presence of various flavonoids and polyphenols, their presence was further ascertained by chemical tests. It has been proposed that the synergistic effect of curcumin as well phenolics, crude extracts of turmeric showed promising antibacterial potential against multidrug resistant bacteria.

Multiplex real-time PCR for detection of <i>qac A/B</i> and <i>smr</i> genes in Gram-positive bacteria

Background. Disinfectants are effective means of non-specific prevention of infections associated with the provision of medical care. Violation of disinfectant use regimes leads to the formation of microorganism resistance to them. To monitor the spread of clinically significant microorganisms resistant to disinfectants, the development of methods for their detection, including molecular genetic methods, remains relevant. The aim of the study was to develop a multiplex real-time PCR for the identification of qacA/B and smr genes, the determinants of resistance to cationic biocides, in Gram-positive bacteria. Materials and methods. Conserved regions of qacA, qacB and smr genes were searched, and primers and probes were designed using BLASTN, GeneRunner, and Multiple Primer Analyzer programs. To evaluate the analytical sensitivity of the multiplex PCR, plasmids pTZ57-qacA/B, pTZ57-smr, and pTZ57-16S containing qacA/B, smr and 16S rRNA gene fragments of 197 bp, 127 bp, and 287 bp, respectively, were constructed. The method was tested on clinical isolates of Gram-positive bacteria (n = 30). Results. A multiplex real-time PCR using TaqMan probes was developed for the detection of qacA/B and smr genes in Gram-positive bacteria. The 16S rRNA gene was used as an internal amplification control. The sensitivity of the multiplex PCR was 103 copies for all genes. Multiplex PCR validation showed that qacA/B genes were present in 30%, smr genes were present in 10% of the isolates tested. The reproducibility of the results was 100%. Conclusion. The developed multiplex PCR differs from existing assays by high specificity and short turnaround time, as well as by the presence of an internal amplification control. It can be used for the detection of Gram-positive bacteria potentially resistant to cationic biocides.

Prevalence of multidrug-, extensively drug-, and pandrug-resistant bacteria in clinical isolates from King Khaled Hospital, Najran, Saudi Arabia

BackgroundSaudi Arabia faces a growing antimicrobial resistance (AMR) problem, exacerbated by the widespread use of antibiotics in clinical and agricultural settings. Despite this, AMR surveillance has been limited, particularly in regions like Najran, making this study critical for informing local and national public health strategies.AimThis study explored the prevalence of multidrug-resistant, extensively drug-resistant, and Pandrug-resistant bacteria in Najran, Saudi Arabia.Study designThis is a cross-sectional study.MethodsThis study included 559 diverse clinical samples (urine, wound, etc.) collected from various departments in King Khaled Hospital, Saudi Arabia. The Phoenix BD instrument was used for complete bacterial identification and antibiotic sensitivity testing. Demographic and clinical data were analyzed statistically.ResultsOf the 559 samples, the culture positivity rates were as follows: 51% for Escherichia coli, 22% for Staphylococcus aureus, 14% for Klebsiella pneumoniae, 6% for Acinetobacter baumannii, 6% for Pseudomonas aeruginosa, and 1% for Enterococcus faecium. Majority of the cases were from male (57%), and age 50+ (59%) recorded highest cases. Participants from outpatient department (OPD) ward recorded the highest (56%) cases, while urine sample recorded the highest (49%) cases. About 84% of the isolates were multidrug‑resistance (MDR), 10% were extensively drug‑resistance (XDR), and 6% pandrug‑resistance (PDR). Our analysis showed high sensitivity to Oxazolidonone, Tetracycline, carbapenems, Lipopeptide, Aminoglycopeptide classes of antibiotics.ConclusionsThe study revealed a high prevalence of drug resistance, highlighting the critical importance of continued surveillance and research to mitigate the spread of antimicrobial resistance and preserve the effectiveness of existing therapies.

THE PREVALENCE OF (OMPA, CSUE) GENES AMONG BIOFILM PRODUCER ACINETOBACTER BAUMANNII ISOLATES

Acinetobacter baumannii is a significant public health problem because it is capable of forming biofilms that may be responsible for the survival of this pathogen in the hospital environment. The aim of this study is to determine the role of (OmpA, CsuE) genes in biofilm production among A. baumannii isolates. A total of 100 clinical isolates of bacteria were collected from a different sources. All isolates were identified by biochemical test, specific selective media (CHROMagar) and polymerase chain reaction by detection presence of (blaOXA51) gene. only 60 isolates were diagnosed as A. baumannii, and to determine the biofilm production capacity two different methods were used Congo red agar method(CRA) and Microtiter plate method (MTP). MTP method result showed 85% of isolates were able to form biofilms, on the other hand, 33.33% of isolates had a biofilm production ability by showing bright black colonies on CRA. Conventional PCR was used to detect the presence of (OmpA, CsuE) genes and the result showed the prevalence of both genes in all isolates were 97%(58/60). It also shows a strong correlation between the presence of these genes and biofilm formation.

In vitro Study of Biofilm Sensitivity of to the Enzyme Complex Included in Wobenzym

Background. Bacterial films are a marker of chronic recurrent infections. Biofilms on mucous membranes block the inflammatory response of the macroorganism, suppressing the activity of immunocytes, and thereby allow microorganisms to reach high concentrations. Currently, research is being conducted to find medications that can act on biofilms. Enzymes, especially their complexes, are substances that can destroy bacterial films. Objective. Еo determine in vitro the sensitivity of bacterial biofilms formed by vaginal microorganisms to the complex of enzymes included in Wobenzym. Materials and methods. The study included 72 clinical isolates of pure microorganism cultures isolated from the vaginal biotope: Gardnerella vaginalis (3), Enterococcus faecalis (9), Escherichia coli (18), Klebsiella pneumoniae (15), Klebsiella aerogenes (3), Lactobacillus crispatus (3), Streptococcus pyogenes (3), Acinetobacter baumanii (3), Staphylococcus aureus (3), Candida albicans (3), Enterococcus faecium (3), Streptococcus agalactiae (3), Lactobacillus acidophilus (3). Bacterial biofilm formation was determined in polystyrene flat-bottom plates using a modified method of Christensen et al. (1985). The tablet form of Wobenzym was used in the study. The tablet shell was washed with saline, the tablet itself was dissolved in 10 ml of 0.9% NaCl and used for in vitro studies. The result was determined using a reader on a spectrophotometer to determine the optical density (OD) of the formed biofilm. It was believed that the drug acted on the bacterial film, reducing the OD by more than three times. Results. An in vitro study revealed clinical isolates of bacteria that formed biofilms of varying severity. Of the 72 clinical bacterial isolates, 38 formed biofilms. A pronounced effect of the complex of enzymes included in Wobenzym on biofilms formed by microorganisms such as A. baumanii, S. aureus, G. vaginalis and E. faecalis was noted. Conclusion. Wobenzym has an effective destructive effect on biofilms formed by various microorganisms, including G. vaginalis, common causative agents of bacterial vaginosis, as well as staphylococci and enterococci, causative agents of aerobic (nonspecific) vaginitis. Conclusion. The drug Wobenzym has an effective destructive effect on biofilms formed by various microorganisms, including Gardnerella vaginalis, common causative agents of bacterial vaginosis, as well as staphylococci and enterococci, causative agents of aerobic (nonspecific vaginitis).

Influence of a synthetic analogue of the active center of GM-CSF – peptide ZP2 on the growth and biofilm formation of gram-negative bacteria – causes of surgical infections

The aim is to analyze the nature of the effect of the synthetic analogue of the active center of GM- CSF – peptide ZP2 on the growth and biofilm formation (BPO) of gram–negative bacteria – pathogens of surgical infections. The study used 18 clinical isolates of gram-negative bacteria of different species (Klebsiella pneumoniae, Citrobacter freundii, Stenotrophamonas maltophilia) isolated from purulent wounds in patients with surgical pathology and showing pronounced resistance to many antibiotics used in clinical practice. The isolation of pure cultures of microorganisms was carried out by conventional methods; species were assessed by direct protein profiling using a MALDI TOF mass spectrometer. To study the effect of ZP2 peptide on bacterial growth and BPO, isolates were co-cultured with a solution of ZP2 peptide in meat-peptone broth (MPB) at a concentration of 5 micrograms/ml at 37°C for 24-48 hours. The effect of the ZP2 peptide was studied both on emerging biofilms and on those formed, according to the degree of binding of crystalline violet in sterile 96-well polystyrene plates. Next, Growth inhibition indices and coefficients of BPO of microorganisms were determined. It was found that the synthetic analogue of the active center of granulocyte-macrophage colony stimulating factor (GM-CSF) – peptide ZP2 inhibited the growth of the studied bacterial strains, reducing the biomass of experimental cultures during the development of bacterial populations. At the same time, the species-specific effect of the ZP2 peptide on the ability of surgical strains of the studied bacteria to form biofilms has been shown. It was experimentally established that all the studied surgical strains of microorganisms were capable of biofilm formation, and the maximum severity of the trait was characteristic of S. maltophilia isolates. The synthetic analogue of the active center of granulocyte-macrophage colony stimulating factor (GM-CSF) – peptide ZP2 caused a decrease in the ability to form biofilms in isolates S. maltophilia and destroyed already formed biofilms in all studied species of microorganisms. The experimental data obtained expand the range of potential clinical applications of the synthetic analogue of the active center of granulocyte-macrophage colony stimulating factor (GM-CSF) – peptide ZP2, and its use in new medicines can be effective in combating antibiotic-resistant pathogens of surgical infections.

In Vitro and In Vivo Studies on a Mononuclear Ruthenium Complex Reveals It is a Highly Effective, Fast-Acting, Broad-Spectrum Antimicrobial in Physiologically Relevant Conditions.

The crystal structure of a previously reported antimicrobial RuII complex that targets bacterial DNA is presented. Studies utilizing clinical isolates of Gram-negative bacteria that cause catheter-associated urinary tract infection, (CA)UTI, in media that model urine and plasma reveal that good antimicrobial activity is maintained in all conditions tested. Experiments with a series of Staphylococcus aureus clinical isolates show that, unlike the majority of previously reported RuII-based antimicrobial leads, the compound retains its potent activity even in MRSA strains. Furthermore, experiments using bacteria in early exponential growth and at different pHs reveal that the compound also retains its activity across a range of conditions that are relevant to those encountered in clinical settings. Combinatorial studies involving cotreatment with conventional antibiotics or a previously reported analogous dinuclear RuII complex showed no antagonistic effects. In fact, although all combinations show distinct additive antibacterial activity, in one case, this effect approaches synergy. It was found that the Galleria Mellonella model organism infected with a multidrug resistant strain of the ESKAPE pathogen Acinetobacter baumannii could be successfully treated and totally cleared within 48 h after a single dose of the lead complex with no detectable deleterious effect to the host.

A New Casjensviridae Bacteriophage Isolated from Hospital Sewage for Inactivation of Biofilms of Carbapenem Resistant Klebsiella pneumoniae Clinical Isolates.

Klebsiella pneumoniae, a member of the ESKAPE pathogen group, is a prominent cause of hospital-acquired infections. The WHO has recognized carbapenem-resistant K. pneumoniae as a critical-one priority pathogen. These resilient superbugs have the ability to form biofilms and present a significant global threat. In the present study, we isolated and characterized a bacteriophage SAKp02, from hospital sewage, infectious to carbapenem-resistant K. pneumoniae patient isolates. SAKp02 could infect 43 of 72 clinical isolates, indicating a broad host spectrum. Whole genome analysis classified SAKp02 within the family Casjensviridae, with a 59,343 bp genome encoding 82 ORFs. Comparative genomic analysis revealed significant differences between SAKp02 and its closest viruses, indicating a distinct genetic makeup positioning it as a novel phage strain within the lineage. The SAKp02 genome comprises bacteriolytic enzymes, including holin, endolysin, and phage depolymerase, crucial for bacterial lysis and biofilm disruption. It reduced biofilm biomass by over threefold compared to the control and eradicated 99% of viable cells within a 4 h treatment period. Scanning electron microscopy corroborated the ability of the phage to dismantle biofilm matrices and lyse bacterial cells. Safe and effective treatments are warranted, and hence, the fully characterized lytic phages with therapeutic potential against drug-resistant clinical isolates of bacteria are needed. Our study is the first to report the antibacterial and antibiofilm activity of Casjensviridae phages, and our discovery of a novel K. pneumoniae phage broadens the arsenal against the bacteria.

Species diversity of clinical isolates of bacteria of the genus Clostridium circulating in dairy complexes of the Sverdlovsk region

Species diversity of clinical isolates of bacteria of the genus Clostridium circulating in dairy complexes of the Sverdlovsk region

Pharmacological and behavioral investigation of putative self-medicative plants in Budongo chimpanzee diets.

Wild chimpanzees consume a variety of plants to meet their dietary needs and maintain wellbeing. While some plants have obvious value, others are nutritionally poor and/or contain bioactive toxins which make ingestion costly. In some cases, these nutrient-poor resources are speculated to be medicinal, thought to help individuals combat illness. In this study, we observed two habituated chimpanzee communities living in the Budongo Forest, Uganda, and collected 17 botanical samples associated with putative self-medication behaviors (e.g., bark feeding, dead wood eating, and pith-stripping) or events (e.g., when consumer had elevated parasite load, abnormal urinalysis, or injury). In total, we selected plant parts from 13 species (nine trees and four herbaceous plants). Three extracts of different polarities were produced from each sample using n-hexane, ethyl acetate, and methanol/water (9/1, v/v) and introduced to antibacterial and anti-inflammatory in vitro models. Extracts were evaluated for growth inhibition against a panel of multidrug-resistant clinical isolates of bacteria, including ESKAPE strains and cyclooxygenase-2 (COX-2) inhibition activity. Pharmacological results suggest that Budongo chimpanzees consume several species with potent medicinal properties. In the antibacterial library screen, 45 out of 53 extracts (88%) exhibited ≥40% inhibition at a concentration of 256 μg/mL. Of these active extracts, 41 (91%) showed activity at ≤256μg/mL in subsequent dose-response antibacterial experiments. The strongest antibacterial activity was achieved by the n-hexane extract of Alstonia boonei dead wood against Staphylococcus aureus (IC50: 16 μg/mL; MIC: 32 μg/mL) and Enterococcus faecium (IC50: 16 μg/mL; MIC: >256 μg/mL) and by the methanol-water extract of Khaya anthotheca bark and resin against E. faecium (IC50: 16 μg/mL; MIC: 32 μg/mL) and pathogenic Escherichia coli (IC50: 16 μg/mL; MIC: 256 μg/mL). We observed ingestion of both these species by highly parasitized individuals. K. anthotheca bark and resin were also targeted by individuals with indicators of infection and injuries. All plant species negatively affected growth of E. coli. In the anti-inflammatory COX-2 inhibition library screen, 17 out of 51 tested extracts (33%) showed ≥50% COX-2 inhibition at a concentration of 5 μg/mL. Several extracts also exhibited anti-inflammatory effects in COX-2 dose-response experiments. The K. anthotheca bark and resin methanol-water extract showed the most potent effects (IC50: 0.55 μg/mL), followed by the fern Christella parasitica methanol-water extract (IC50: 0.81 μg/mL). This fern species was consumed by an injured individual, a feeding behavior documented only once before in this population. These results, integrated with associated observations from eight months of behavioral data, provide further evidence for the presence of self-medicative resources in wild chimpanzee diets. This study addresses the challenge of distinguishing preventative medicinal food consumption from therapeutic self-medication by integrating pharmacological, observational, and health monitoring data-an essential interdisciplinary approach for advancing the field of zoopharmacognosy.

Clinical Evaluation of VITEK MS PRIME with PICKME Pen for Bacteria and Yeasts, and RUO Database for Filamentous Fungi.

The VITEK MS PRIME (bioMérieux, Marcy-l'Étoile, France), a newly developed matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) system, alongside the VITEK PICKME pen (PICKME), offers easy sample preparation for bacteria and yeasts. The VITEK MS PRIME also offers two software platforms for filamentous fungi: the IVD database and the RUO database. Our study evaluated its identification agreement on 320 clinical isolates of bacteria and yeasts, comparing PICKME and traditional wooden toothpick sampling techniques against MicroIDSys Elite (ASTA) results. Additionally, we assessed the IVD (v3.2) and SARAMIS (v4.16) RUO databases on 289 filamentous fungi against molecular sequencing. The concordance rates for species-level identification of bacteria and yeasts were about 89.4% (286/320) between the PICKME and wooden toothpick, and about 83.4-85.3% between the VITEK MS PRIME and ASTA MicroIDSys Elite. Retesting with PICKME improved concordance to 91.9%. For filamentous fungi, species-level identification reached 71.3% with the IVD database and 85.8% with RUO, which significantly enhanced basidiomycetes' identification from 35.3% to 100%. Some strains in the IVD database, like Aspergillus versicolor, Exophiala xenobiotica, and Nannizzia gypsea, failed to be identified. The VITEK MS PRIME with PICKME offers reliable and efficient microorganism identification. For filamentous fungi, combined use of the RUO database can be beneficial, especially for basidiomycetes.

Simple, sensitive, and visual detection of 12 respiratory pathogens with one-pot-RPA-CRISPR/Cas12a assay.

Respiratory infections pose a serious threat to global public health, underscoring the urgent need for rapid, accurate, and large-scale diagnostic tools. In recent years, the CRISPR/Cas (clustered regularly interspaced short palindromic repeats/CRISPR-associated) system, combined with isothermal amplification methods, has seen widespread application in nucleic acid testing (NAT). However, achieving a single-tube reaction system containing all necessary components is challenging due to the competitive effects between recombinase polymerase amplification (RPA) and CRISPR/Cas reagents. Furthermore, to enable precision medicine, distinguishing between bacterial and viral infections is essential. Here, we have developed a novel NAT method, termed one-pot-RPA-CRISPR/Cas12a, which combines RPA with CRISPR molecular diagnostic technology, enabling simultaneous detection of 12 common respiratory pathogens, including sixbacteria and sixviruses. RPA and CRISPR/Cas12a reactions are separated by paraffin, providing an independent platform for RPA reactions to generate sufficient target products before being mixed with the CRISPR/Cas12a system. Results can be visually observed under LED blue light. The sensitivity of the one-pot-RPA-CRISPR/Cas12a method is 2.5 × 100copies/μL plasmids, with no cross-reaction with other bacteria or viruses. Additionally, the clinical utility was evaluated by testing clinical isolates of bacteria and virus throat swab samples, demonstrating favorable performance. Thus, our one-pot-RPA-CRISPR/Cas12a method shows immense potential for accurate and large-scale detection of 12 common respiratory pathogens in point-of-care testing.

Green synthesized silver nanoparticles (AgNPs) using aqueous extract of <i>Calotropis procera</i> and its antimicrobial activity on clinical bacteria isolates

The green synthesis of nanoparticles, utilizing aqueous plant extract as a capping and stabilizing agent, has attracted significant attention in various domains, particularly in pharmaceuticals and drug delivery. In this investigation, silver nitrate (AgNO3) salts were employed as precursors to fabricate silver nanoparticles using Calotropis procera (leaves/flower) extract, and the resulting nanoparticles were characterized. Fourier Transform Infrared (FTIR) spectroscopy revealed three primary functional groups at peaks of 2851.4 cm-1, 1543.1 cm-1, and 1323.2 cm-1, responsible for capping and stabilizing the synthesized C.p-AgNPs. Scanning Electron Microscopy (SEM) demonstrated that the synthesized C.p-AgNPs exhibited spherical shapes with an average particle size ranging from 20 nm to 30 nm. Energy-dispersive X-ray (EDX) analysis of the synthesized C.p-AgNPs indicated the presence of pure silver (Ag) at 54.32% in the region of 2.7 to 3.1 keV. Furthermore, the antimicrobial activity of C.p-AgNPs was examined, with the best inhibition observed at 0.5 mg/mL on Gram-negative bacteria S. aureus (12.0 mm) and Streptococcus spp (13.0 mm), and on Gram-positive bacteria E. coli (16.0 mm) and Salmonella spp (14.0 mm). The antimicrobial efficacy was dose-dependent, suggesting the potential for eradicating resistant human pathogenic bacteria. The antibacterial potential of C.p-AgNPs could be enhanced by increasing their concentration, depending on the specific application. Based on the study's findings, C.p-AgNPs derived from Calotropis procera can be employed for various biomedical purposes, such as textile coating by incorporating C.p-AgNPs in fibers and food storage by nanocapsulation of food items to extend their shelf life.

Understanding the significance of microbiota recovered from health care surfaces

Microbial contamination of hospital surfaces remains despite adherence to routine disinfection. Our study demonstrates bioburden from various types of hospital high-touch surfaces and the pathogenicity of all bacteria recovered. Several high-touch hospital surfaces from a single medical-surgical unit were sampled and cultured using replicate organism detection and counting (RODAC) Tryptic Soy agar plates. Colonies were then subcultured to blood agar plates and speciated using MALDI-TOF. The local microbiology laboratory database was queried for any clinical isolate match with the environmental samples recovered. Manikins, bed rails, and workstations-on-wheels were the most contaminated surfaces with the largest variety of bacteria isolated from manikins and bed rails. A total of 60 different types of pathogens were isolated, 18 of which were well-known pathogens, and 7 were classified as important in the health care setting by CDC. Our clinical microbiology laboratory identified 29 of 60 hospital surface bacteria in clinical isolates. Urine, soft tissue, and blood were the most common sources of clinical isolates. Surfaces in the health care environment harbor both well-known and not-so-well-known human pathogens. Several not-so-well-known pathogens are skin flora or environmental bacteria, which in the right setting, can become pathogenic and cause diseases including meningitis, brain abscess, endocarditis, and bacteremia.

Evaluating Fluoxetine's Growth-Inhibitory Impact on Clinical Isolates of Enteric Bacteria: Harnessing Repurposing Potential

The over-the-counter use and imprudent utilization of antibiotics in recent times have led to the emergence of microbial resistance. This has given rise to an alarming situation, prompting researchers to explore novel strategies for managing infections induced by antibiotic-resistant species. However, the process of drug discovery is time-consuming and expensive, which makes it a challenging endeavor. In recent years, drug repurposing has gained significant attention as an alternative strategy. Notably, several antidepressants have piqued interest as potential candidates for repositioning as antibiotics. Thus, the present study was aimed at investigating the anti-bacterial potential of different classes of antidepressants i.e., fluoxetine, venlafaxine, and phenelzine in clinical isolates of Escherichia coli, Enterobacter aerogenes, Enterococcus faecalis, Klebsiella pneumonia, Pseudomonas aeruginosa, Proteus mirabilis, Salmonella typhi, Shigella dysenteriae, and Staphylococcus aureus. The strains were cultivated on Mueller Hinton agar, with the aforementioned antidepressants or conventional antibiotics. Following a 24-hour incubation period, the extent of growth inhibition was assessed by measuring the zone of inhibition, serving as an indicator of their inhibitory potential. The findings showed that fluoxetine arrested the growth of almost all isolates with maximal effect against Pseudomonas aeruginosa. The impact of venlafaxine was exclusively observed in Enterobacter aerogenes, with phenelzine demonstrating complete ineffectiveness in bacterial growth suppression. In conclusion, the current study elucidates the efficacy of fluoxetine in clinical isolates, thereby positioning it as a promising contender for the advancement of novel antimicrobial agents. Additionally, our data raises questions regarding the proposed mechanisms of antibacterial action for selective serotonin reuptake inhibitors (SSRIs) and challenges the notion of dysbiosis as a potential mode of action for antidepressants.

Bio Evaluation of Lantibiotic Nisin Loaded Polyvinyl Alcohol – Sodium Alginate Crosslinked Hydrogel As Novel Dental Temporary Filling Material

The incidence of oro-dental disorders has emerged as a serious threat to the healthcare sector owing to the increasing complexity of the oral microbiome. Significant advances in biomaterial research have led to the advent of a plethora of drug delivery systems including nanocarriers, dendrimers, hydrogels and other kinds of stimuli-responsive polymeric biomaterials. Anti-microbial peptides (AMPs) have engendered considerable interest in the past decades as potential alternatives to traditional disinfecting agents and also emerged as potent antibiofilm agents. Among the most viable approaches in targeted drug delivery, hydrogels incorporated with AMPs are emerging as bio-functional platforms yielding increased stability and bioavailability. The antibacterial and antibiofilm activities of Nisin are studied using microbiological methods followed by the synthesis of Nisin loaded PVA-Alginate hydrogel for dental treatment. The physicochemical characteristics of Nisin loaded hydrogel were done by swelling behavior, release kinetics assay, FTIR spectroscopic methods and cytotoxicity studies. Nisin showed antibacterial activity towards clinical isolates of drug-resistant bacteria and the antibiofilm and anti-adhesion studies demonstrated that Nisin could control the bacterial count in the test sample. The polymerization of Nisin into hydrogels was done and the physico-chemical characterization of Nisin loaded hydrogel network could be envisaged as a potential drug delivery platform for oral infections. Nisin loaded PVA-Alginate biocompatible hydrogel exhibited apparent swellable, flexible, nonhaemolytic materials and active antimicrobial and nontoxic materials. Physicochemical properties of these Nisin loaded PVA-Alginate biocompatible hydrogels have great potential in biomaterial-based drug delivery systems in controlling the growth and proliferation of major oro-dental pathogens. This could be exploited for the temporary biocompatible dental filling materials to treat the caries. Exploring potential nisin loaded hydrogel delivery systems will provide a brighter future of more friendly, effective and personalized treatment to deal with dental caries.

In Vitro Evaluation of Rose Bengal Photoactivated by Custom-Built Green Light-Emitting Diode Source for Bacteria and Rapidly Growing Mycobacteria Inhibition.

In vitro evaluation of rose bengal (RB) photoactivated by our custom-built green light-emitting diode (LED) source for the growth inhibition of bacterial strains and rapidly growing mycobacterial (RGM) isolates in infectious keratitis. Six corneal clinical bacteria isolates were included in this study: two Gram-positive bacteria (methicillin-resistant Staphylococcus aureus [MRSA] and Staphylococcus epidermidis), two Gram-negative bacteria (Pseudomonas aeruginosa and Serratia marcescens), and two RGM (Mycobacterium chelonae and Mycobacterium abscessus). Microorganisms were cultured and incubated at specific conditions and prepared in suspensions to adjust their concentration to 104 cells/mL. Different treatments were conducted in triplicates: Group I, no treatment; Group II, treated with 0.1% rose bengal alone (exposed to dark for 30minutes); Group III, exposed to custom green LED for 30minutes (12.87 J/cm2); and Group IV, treated with 0.1% rose bengal and exposed to custom green LED for 30 minutes. Agar plates were incubated at specific conditions and photographed after growth for pixel analyses. Complete growth inhibition of all bacteria and RGM was observed in Group IV. MRSA and S. epidermidis in Group II also showed complete growth inhibition. The custom-built green LED presented good activity by photoactivating RB and inhibiting micro-organism growth. For the first time, we demonstrated the expressive growth inhibition effect of RB against S. epidermidis, RGM, and S. marcescens. Clinical treatment with RB may offer an alternate adjunct therapy for corneal surface infections. Validating in vitro the custom-built green LED encourages the clinical application for the treatment of infectious keratitis.

A gold nanoparticle colorimetric probe-based biosensor for rapid detection of VIM-2 and IMP-1 metallo-beta lactamase genes

Despite actions to reduce the prevalence of antibiotic resistance, antibiotic resistance remains a major threat in the treatment and control of infections. Therefore, the development of rapid diagnostic methods plays a significant role in the detection of antibiotic resistance genes and the management of hospital infections. This study aimed to design and develop a gold nanoparticle colorimetric probe-based biosensor was developed for faster and more accurate detection of VIM-2 and IMP-1 Metallo-Beta-Lactamases (MBLs) genes in different clinical samples. After identifying 248 clinical isolates of bacteria with standard biochemical methods and evaluation of antibiotic resistance and identifying MBL-producing strains, PCR method was carried out for detecting VIM-2 and IMP-1 genes as a gold standard. Synthesis of AuNPs were done by citrate reduction method and AuNP -IMP-1 biosensor was used for detecting IMP-1 gene, after functionalization of thiol modified oligonucleotides. AuNP biosensor and IMP-1 PCR were compared in terms of detection indices. Method PCR was defined as the gold standard. Bacteria examined, 87 isolates were resistant to carbapenems. Out of the 87 carbapenem-resistant isolates, 85 (34.2%) were phenotypically positive for MBLs. Also, 7 isolates had IMP-1 gene, but none of them carried VIM-2 gene. The AuNP biosensor had 100% sensitivity, specificity, PPV and NPV, respectively. The final detection limit of IMP-1 genomic DNA (LOD) by PCR and AuNP-IMP-1 biosensor technique was 0.1 fg/μl (2.5 fg/25 reactions) and 0.001 fg/μl (0.025 fg/25 reaction), respectively. According to the promising results of Diagnostic indices, AuNP biosensor is a more efficient and accurate method for direct and indirect detection of antibiotic resistance genes in clinical samples.

Characterization of aminoglycoside resistance genes in multidrug-resistant Klebsiella pneumoniae collected from tertiary hospitals during the COVID-19 pandemic.

Since the peak of the coronavirus disease 2019 (COVID-19) pandemic, concerns around multidrug-resistant (MDR) bacterial pathogens have increased. This study aimed to characterize aminoglycoside resistance genes in MDR Klebsiella pneumoniae (K. pneumoniae) collected during the COVID-19 pandemic. A total of 220 clinical isolates of gram-negative bacteria were collected from tertiary hospitals in Makkah, Saudi Arabia, between April 2020 and January 2021. The prevalence of K. pneumoniae was 40.5%; of the 89 K. pneumoniae isolates, MDR patterns were found among 51 (57.3%) strains. The MDR isolates showed elevated resistance rates to aminoglycoside agents, including amikacin (100%), gentamicin (98%), and tobramycin (98%). PCR assays detected one or more aminoglycoside genes in 42 (82.3%) MDR K. pneumoniae strains. The rmtD gene was the most predominant gene (66.7%; 34/51), followed by aac(6')-Ib and aph(3')-Ia (45.1%; 23/51). The aac(3)-II gene was the least frequent gene (7.8%; 4/51) produced by our isolates. The rmtC gene was not detected in the studied isolates. Our findings indicated a high risk of MDR bacterial infections through the COVID-19 outbreak. Therefore, there is a need for continuous implementation of effective infection prevention control (IPC) measures to monitor the occurrence of MDR pathogens and the emergence of MDR bacterial infections through the COVID-19 outbreak.

A Novel and Low-cost Approach for Intravitreal Injection in an Experimental Model of Endophthalmitis.

Animal models are necessary in understanding the pathogenesis of endophthalmitis and are also necessary to assist the development of new therapeutics for this sight-threatening ocular inflammation. Hamilton syringes are usually preferred to inject pathogens when performing experiments on test subjects, however, this method has technical and financial disadvantages. In this study, we report the findings and assess the related benefits of applying a novel low-cost intravitreal injection technique to initiate endophthalmitis in a mouse model while using the Eppendorf tip and a 26G needle. The 18-hr culture of clinical isolates of bacteria (Staphylococcus aureus and Pseudomonas aeruginosa) and fungus (Aspergillus flavus and Candida albicans) were resuspended to a final concentration of 10,000 colony forming units (CFU)/1 µL which were separately injected intravitreally into C57BL/6 mice (6-8 weeks) using a 0.1-2.5µL pipette attached to the modified Eppendorf tip with a 26G needle. The contralateral eye served as vehicle/uninjected control. Disease progression was determined by assessing the corneal haze, opacity, bacterial burden, and retinal histology of the eyes used in the model. Following euthanization, bacteria-infected mice were enucleated after 24 hr of the initial injection, and fungus-infected mice after 72 hr. Of the 50 mice injected, the modified technique was successful in 48 mice. Two mice were excluded due to cataract formed by accidental injury to the lens. The experimental endophthalmitis mice model successfully mimicked the natural clinical course. Clinical assessment and histopathology confirmed the influx of inflammatory cells into the posterior segment of the eye along with dissolution of retinal architecture. Our novel method of injection using a modified Eppendorf tip and 26G needle yielded a cost-effective mouse model of clinical endophthalmitis, resulting in reproducible infection for understanding various aspects of its pathobiology.