Hemolysin Production Research Articles

Utilization of zein nano-based system for promoting antibiofilm and anti-virulence activities of curcumin against Pseudomonas aeruginosa

Abstract Bacterial biofilms contribute to increased pathogenesis and bacterial resistance. Biofilms can enhance pathogenicity by shielding bacteria from the immune system and antibiotics, and they are associated with persistent infections. Additionally, the antibiotic resistance mechanisms within biofilms make them challenging to treat, emphasizing the need for strategies to be addressed. Mitigating bacterial virulence is a promising strategy that could ease their eradication by host immunity without stressing bacteria to induce resistance. The merits of this strategy are augmented when using safe anti-virulence candidates in proper formulations. The current study aimed to evaluate the antibiofilm and anti-virulence efficacy of curcumin–zein nanoparticles against Pseudomonas aeruginosa. In vitro investigations were performed to assess the effect of nanoparticles on biofilm formation, bacterial motility, and production of virulence factors, including proteases, hemolysins, and pyocyanin, in comparison to bulk curcumin. Furthermore, the effect on the expression of the genes that encode quorum sensing (QS) systems that regulate bacterial virulence was assessed. An in silico study was done to evaluate the affinity of curcumin to QS receptors. Additionally, an in vivo protection assay was performed to evaluate the inhibitory effect of our preparation on diminishing the P. aeruginosa’s capacity to induce pathogenesis. The results showed significant antibiofilm and anti-virulence activities of the curcumin–zein nanoparticles compared to bulk curcumin. These anti-virulence activities were attributed to the curcumin’s interfering with the P. aeruginosa QS systems that regulate its virulence. In conclusion, curcumin acquires significant anti-QS, anti-virulence, and antibiofilm activities that are vastly enhanced upon loading on zein nanoparticles.

Screening and characterization of Enterococcus durans isolates from raw organic milk in Southern Brazil: Assessing technological potential

This study assessed 34 strains of Enterococcus durans isolated from 8 samples of raw organic milk collected in both winter and summer seasons, with the aim of evaluating their technological capability. To achieve this, the following traits were tested: diacetyl production capability, autolysis capacity, organic acid production, expression of proteolytic and lipolytic enzymes, antagonistic capacity against pathogenic bacteria, as well as resistance to different types of antibiotics, hemolysin production, gelatinase production, and biofilm formation ability, as virulence factors. It was observed that 2.9% of the isolates exhibited the ability to produce diacetyl and showed proteolytic and autolytic capacity. Additionally, 8.8% displayed autolytic capacity, and 5.9% exhibited antagonistic capacity against Escherichia coli and Listeria monocytogenes, demonstrating that there are isolates with technological use potential.

An active learning card game to teach microbial pathogenesis to undergraduate biology majors.

Interactive classroom activities are an effective way to reinforce knowledge and promote student engagement. In this paper, we introduce the Pathogenesis Card Game (PCG), an innovative card game that engages students in a battle between microbial pathogens and the host immune system. Each student is given a set of cards that consist of either common host defenses or common pathogen evasion strategies. In pairs, students play a host defense card versus a pathogenesis card. Host defense cards include neutralize (antibody production), eat (phagocytosis), and destroy (degranulation). Pathogenesis cards present evasive strategies including mimic (molecular mimicry), escape (hemolysin production), hide (polysaccharide capsule), block (antioxidant defense), cut (protease secretion), and disguise (antigenic variation). Students develop a mastery of microbial pathogenesis through active gameplay by deliberating the outcome of each unique host-pathogen interaction. Furthermore, they learn the role of cells in the immune system and how pathogens can evade these immune defenses. PCG was piloted in a 300-level introductory microbiology course for 22 undergraduate students, comprising primarily biology and nursing majors. Both quantitative and qualitative student evaluations of the activity strongly suggest that PCG is an engaging, effective, and useful way to teach microbial pathogenesis. This activity provides a 60-minute lesson plan and corresponding materials that can be used to facilitate the introduction of pathogenesis to a typical undergraduate microbiology course. PCG offers instructors a framework to teach microbial pathogenesis and gives students the opportunity to construct their own knowledge about pathogen immune evasion in an engaging and interactive way.

Transcriptome analysis reveals the inhibitory mechanism of phloretin on virulence expression of Staphylococcus aureus and its application in cooked chicken

Staphylococcus aureus (S. aureus) enterotoxins have aroused great concern to food safety owing to its increased risk of food poisoning. The current research aimed to investigate the anti-virulence mechanisms of phloretin against S. aureus in terms of toxin activity and gene expression. The results indicated that phloretin could effectively inhibit the production of hemolysins and enterotoxins, and its anti-virulence effect was exerted in a concentration-dependent manner. Transcriptome results indicated that phloretin could downregulate the transcription level of majority virulence factors related genes (68 %) of S. aureus, including the quorum sensing-related genes (agrB, agrC, agrA, sspA, splF, splD and others) and bacterial secretion system-related genes (secDF, secY2, and yidC). In addition, it was speculated that phloretin was most likely to bind to the AgrA DNA binding domain, thereby affecting the expression of downstream virulence genes (hla, seb, spa, rot, geh, etc) based on molecular docking. Finally, the application in cooked chicken indicated that phloretin could effectively decrease the content of enterotoxins and improve the storage quality of cooked chicken. These findings not only evidenced the feasible anti-virulence activity of phloretin, but also provided a new strategy to prevent S. aureus food poisoning in cooked meat preservation.

Effect of Some Metals Ions on Hemolysin Production from Clinical Isolates of Escherichia Coli

Objective:This study aimed to determine effect of some ions metals (Ca+2, Mn+2, Mg+2, Fe+2, K+, Na+, Zn+2) on hemolysin production was performed. Methods: Eighty Three (83) E. coliisolates collected from different clinical sources from Baghdad Hospitals, performed by using cultural traits, morphological features and biochemical tests, confirmation of identification was done by Vitek 2 system.And it was detected on ability these isolates to production hemolysin by two methods liquid media and agar media. Results: The results showed that: In agar medium revealed that 6 (7.23 %) isolates of E. coli had the ability for producing this enzyme and 77 (92.77%) did not produce hemolysin. The same results were found in liquid medium. Used the microtitration plate method to study the effect these ions metals on hemolysin production.According to the effect of ions metals, the results also showed that MIC value of ions metals was 500μg/mL, hemolysin production was increased after addition each of(Ca+2,Mn+2, Mg+2,Fe+2,K+,Na+) the percentage of hemolysis (96.0 %, 93.4 %, 93.2 %, 93.3%,94.2%, 93.7%) respectively while hemolysin production decreased after addition of Zn+2 with the percentage of hemolysis 0.3%. Conclusion: Based on the influence of metal ions, the findings indicated that hemolysin production exhibited an increase following the addition of each of Ca2+, Mn2+, Mg2+, Fe2+, K+, and Na+ when compared to the control group. Conversely, the introduction of Zn2+ led to a decrease in hemolysin production.

Fecal Carriage of Colibactin-Encoding Escherichia coli Associated With Colorectal Cancer Among a Student Populace.

Fecal carriage of the colibactin (clb) gene in Escherichia coli is described as a source that could promote carcinogenesis, progressing to colorectal cancer. The present study investigated the demographic, dietary, and antibiotic consumption variables as correlates for fecal carriage of clb+/E coli among the student populace. In a randomized cross-sectional survey, E coli (N = 136) from the fecal samples of eligible students were characterized and evaluated for antibiotic resistance, β-lactamase (blm), biofilm, virulence factor production, and strain tryptophan reverse mutagenic activity. The encoded clb+/E coli were analyzed for correlates with principal component analysis. Of all the E coli strains, a low rate of 2 clb+/E coli (1.5%) and higher rates of biofilm (13.2%) and blm producers (11.8%) were recorded among the mutant strains as compared with the nonmutant types. All the clb+/E coli showed complete resistance to amoxicillin, Augmentin (amoxicillin and clavulanate), gentamicin, and trimethoprim/sulfamethoxazole. The fecal clb-encoded E coli (1.5%) were not associated with demographic status, fiber-based food (odds ratio [OR], 1.03; 95% CI, 56.74-138.7; P = .213), alcohol (OR, 1.27; 95% CI, 61.74-147.1; P = .221), antibiotic consumptions (OR, 1.11; 95% CI, 61.29-145.3; P = .222), and handwashing (OR, 1.17; 95% CI, 60.19-145.5; P = .216). The hierarchical cluster of blm+/E coli revealed high-level resistance with a multiantibiotic resistance index ≥0.2 (P < .05). Only 12% of all strains were tryptophan mutant/blm+, and 1.5% of clb+/ECblm+ were observed in fecal samples with a 452-base pair size. Trimethoprim/sulfamethoxazole and biofilm production positively regressed with clb expression (P > .05). Principal component analysis score plot indicated an association of clb+/ECblm+ with dietary pattern, alcohol, blm, and hemolysin production. The combined activity of blm and biofilm production in the gut microbiota could promote clb+/E coli colonization, facilitating genotoxin production and possible colorectal cancer induction.

Identification of safe putative probiotics from various food products.

The objective of this study was to isolate, identify, and assess the safety and functionality in vitro of putative probiotic bacterial strains. Isolation procedures were based on standard methods using elective and selective media. The isolates were identified by comparative 16S rRNA sequencing analysis while their safety was determined according to the safety tests recommended by the FAO/WHO such as antibiotic resistance, hemolysin, and biogenic amine production. Most of the isolates did not pass the in vitro safety tests; therefore, only Lactiplantibacillus plantarum (from ant intestine and cheese), Lacticaseibacillus paracasei (from goat milk and kimchi), Enterococcus faecium (from chili doenjang and vegetables with kimchi ingredients), Limosilactobacillus fermentum (from saliva), and Companilactobacillus alimentarius (from kimchi) were identified and selected for further studies. The isolates were further differentiated by rep-PCR and identified to the strain level by genotypic (16S rRNA) and phenotypic (Gen III) approaches. Subsequently, the strain tolerance to acid and bile was evaluated resulting in good viability after simulated gastrointestinal tract passage. Adhesion to mucin in vitro and the presence of mub, mapA, and ef-tu genes confirmed the adhesive potential of the strains and the results of features associated with adhesion such as hydrophobicity and zeta potential extended the insights. This study reflects the importance of fermented and non-fermented food products as a promising source of lactic acid bacteria with potential probiotic properties. Additionally, it aims to highlight the challenges associated with the selection of safe strains, which often fail in the in vitro tests, thus hindering the possibilities of "uncovering" novel and safe probiotic strains.

Nine New Antibacterial Diterpenes and Steroids from the South China Sea Soft Coral Lobophytum catalai Tixier-Durivault.

Five new cembrane-type diterpenes, lobocalines A-E (1-5), and four new steroids, lobocaloids A-D (9-12), along with six known related compounds (6-8 and 13-15) were isolated from the Yalong Bay soft coral Lobophytum catalai Tixier-Durivault. The structures of the new compounds were elucidated by extensive spectroscopic analysis, NMR calculation with DP4+ analysis, time-dependent density functional theory-electronic circular dichroism (TDDFT-ECD) calculations, X-ray diffraction analyses and comparison with the reported spectroscopic data of known compounds. Further, with the aid of X-ray diffraction analysis, the structure of lobocrasol B (15) was firmly revised as 15a. In in vitro bioassays, compound 2 showed moderate antibacterial activities against fish pathogenic bacteria Streptococcus parauberis KSP28 and Phoyobacterium damselae FP2244 with minimum inhibitory concentration (MIC) values of 8.7 and 17.3 µg/mL, respectively. All the steroids exhibited antibacterial activities against the S. parauberis KSP28 with MIC values ranging from 12.3 to 53.6 µg/mL. Compounds 2, 7 and 14 have remarkable inhibitory effects on the hemolysin production of Staphylococcus aureus, while compounds 8-12 have medium inhibitory effects on the pyocyanin production in Pseudomonas aeruginosa.

Effects of polystyrene nanoplastics on growth and hemolysin production of microalgae Karlodinium veneficum

There are few studies on the effects of nanoplastics on growth and hemolysin production of harmful algal bloom species at present. In this study, Karlodinium veneficum was exposed to different concentrations (0, 5, 25, 50, 75 mg/L) of polystyrene nanoplastics (PS-NPs, 100 nm) for 96 h. The effects of PS-NPs on growth of K. veneficum were investigated by measuring algal cell abundance, growth inhibition rate (IR), total protein (TP), malondialdehyde (MDA), glutathione reductase (GSH), superoxide dismutase (SOD), ATPase activity (Na+/K+ ATPase and Ca2+/Mg2+ ATPase). Scanning electron microscope and transmission electron microscope (SEM and TEM) images of microalgae with or without nanoplastics were also observed. The effects of PS-NPs on hemolysin production of K. veneficum were studied by measuring the changes of hemolytic toxin production of K. veneficum exposed to PS-NPs on 1, 3, 5 and 7 days. High concentrations (50 and 75 mg/L) of PS-NPs seriously affected the growth of K. veneficum and different degrees of damage to cell morphology and ultrastructure were found. Excessive free radicals and other oxidants were produced in the cells, which disrupted the intracellular redox balance state and caused oxidative damage to the cells, and the basic activities such as photosynthesis and energy metabolism were weakened. The athletic ability of K. veneficum was decreased, but the ability to produce hemolysin was enhanced. It was suggested that the presence of nanoplastics in seawater may strengthen the threat of harmful algal bloom species to aquatic ecosystems and human health.

MOLECULAR IDENTIFICATION OF VIRULENCE PROPERTIES AND VIRULENCEASSOCIATED GENE (ISS) OF E. COLI ISOLATED FROM BROILER CHICKS

The present study identified virulence genes for existence of virulence genes increased the serum survival (Iss) for determining the pathogenicity regarding E. coli in broiler chicks. The results indicated that 45 (36.7%) of the 120 samples collected from dead and morbid broiler chicks that have been infected with E. coli, and the difference between non-pathogenic and pathogenic was investigated. Hemolysin production, motility, and the agglutination test have been also shown to be positive. In vitro tests revealed that three isolates have been classed as moderately, highly, and slightly virulent, based on their pathogenicity features. Broiler chicks have been typified by the monovalent antisera had indicated that (31.74%) have been identified as E. coli serotype O2. Slightly and highly pathogenic isolates have been responsive to chloramphenicol, penicillin, gentamicin, and streptomycin, while moderately pathogenic isolates have been only susceptible to the gentamicin and chloramphenicol. The use of the PCR as a valid approach for detecting virulence genes resulted in an increase in serum survival (Iss) in 15 (65.2%) of the total sample

Detection of antimicrobial susceptibility and virulence factors for some bacterial species caused urinary tract infection among type 1 and type 2 diabetes mellitus patients

Abstract Background: Diabetes mellitus (DM), is a metabolic illness caused by a deficiency in insulin production, action, or both, it is characterized by hyperglycemia and disruptions of the metabolism of carbohydrates, proteins, and fats. Urinary tracts infections (UTIs) are conditions when one or more urinary tract structures become contaminated after germs get past the body’s robust natural defenses. The most prevalent illness, UTIs can happen at any moment during a person’s lifetime. UTIs and DM have been linked for many years. Owing to a shift in the host defense mechanism, a micro-vascular illness in the kidney, and the existence of diabetic cystopathy, the incidence of UTIs is significant in DM. Urinary colonization by bacteria is made possible by high glucose concentrations in urine flow. Objective: Detection of antimicrobial susceptibility and virulence factors among bacteria causing UTIs isolated from type 1 and type 2 diabetic patients. Materials and Methods: Between April and July 2022, 178 patients with diabetes who had signs of a UTI had their urine samples taken. Midstream urine samples from DM patients were inoculated into blood agar and MacConkey agar using a calibrated loop (0.001 mL). For 24 h, cultures were incubated at 37°C in an aerobic environment. To determine whether there had been any considerable growth, colonies were counted. Diagnostic microorganisms were tested for their susceptibility to various antibiotics, and virulence factors were found. Results: Significant bacteriuria was observed in 28 of 69 (40.5%) and 52 of 109 (47.7%) urine samples cultured from patients with type 1 and 2 diabetes, respectively. Sensitivity to isolates which isolated from patients with type 1 and type 2 diabetes was highest for meropenem as 90% and 100%, respectively. With regard to virulence factor, it was investigated of biofilm formation, hemolysin production, protease production, urease production, and β-lactamase production. The highest ratio of these factors production in bacteria which isolated from patients with type 1 diabetes was β-lactamase (75.8%). As for patients with type 2 diabetes, the highest ratio was for biofilm formation (79.0%). Conclusion: According to this study, common antimicrobials are very resistant to many different drugs. UTIs are more common than previously thought, and type of diabetes was discovered to be one of the key contributing factors. We found an association between virulence factors of pathogens and type of diabetes.

Repurposing albendazole as a potent inhibitor of quorum sensing-regulated virulence factors in Pseudomonas aeruginosa: Novel prospects of a classical drug

Pseudomonas aeruginosa has emerged as a critical superbug that poses a serious threat to public health. Owing to its virulence and multidrug resistance profiles, the pathogen demands immediate attention for devising alternate intervention strategies. In an attempt to repurpose drugs against P. aeruginosa, this preclinical study was aimed at investigating the antivirulence prospects of albendazole (AbZ), an FDA-approved anti-helminthic drug, recently predicted to disrupt quorum sensing (QS) in Chromobacterium violaceum. AbZ was scrutinized for its quorum quenching (QQ) prospects, effect on bacterial virulence, different motility phenotypes, and biofilm formation in vitro. Additionally, in silico analysis was employed to predict the molecular interactions between AbZ and QS receptors. At sub-inhibitory levels, AbZ demonstrated anti-QS activity and significantly abrogated AHL biosynthesis in P. aeruginosa. Moreover, AbZ significantly downregulated the transcript levels of QS- (lasI/lasR, rhlI/rhlR, and pqsA/pqsR) and QS-dependent virulence (aprA, lasA, lasB, plcH, and toxA) genes in P. aeruginosa. This coincided with reduced hemolysin, alginate, pyocyanin, rhamnolipids, total protease, and elastase production, thereby lowering phenotypic virulence. Molecular docking with AbZ further revealed strong associations and high binding energies with LasR (−8.8 kcal/mol), RhlR (−6.5 kcal/mol), and PqsR (−6.3 kcal/mol) receptors. AbZ also impeded bacterial motility and abolished EPS production, severely compromising pseudomonal biofilm formation. For the first time, AbZ was shown to interfere with QS circuitry and consequently disarming pseudomonal virulence. Hence, AbZ can be exploited for its antivirulence properties against P. aeruginosa.

Selected flavonoids exhibit antibiofilm and antibacterial effects against Vibrio by disrupting membrane integrity, virulence and metabolic activities

Vibrio parahaemolyticus is a high-risk foodborne pathogen associated with raw or undercooked seafoods and its biofilm forming potential has become a threat to food safety and economic values. Hence, this study aims to examine the antibacterial and antibiofilm activities as well as virulence inhibitory effects of selected flavonoids against V. parahaemolyticus. Out of the sixteen flavonoid derivatives, 6-aminoflavone (6-AF), 3,2-dihydroxyflavone (3,2-DHF) and 2,2-dihydroxy-4-methoxybenzophenone (DHMB) were found as active biofilm inhibitors. 3,2-DHF and DHMB had minimum inhibitory concentrations of 20 and 50 μg/mL respectively against Vibrio planktonic cells and displayed superior antibacterial activities to standard controls. Also, they disrupted preformed biofilms and suppressed virulence properties including motilities, cell hydrophobicity and aggregation. They impaired iron acquisition mechanism and hemolysin production at sub-MICs as supported by transcriptomic studies. Interestingly, the flavonoids interfered with the metabolic activity, cell division and membrane permeability to exert antibiofilm and antibacterial activities. 6-AF and 3,2-DHF were non-toxic in the C. elegans model and showed excellent capacity to protect shrimps from biodeterioration. Furthermore, the flavonoids inhibited biofilm formation by V. harveyi, Staphylococcus aureus and Salmonella typhimurium and the mixed-species biofilm with Vibrio. This study discovered flavonoid derivatives, especially 3,2-DHF as potential bioactive compounds capable of offering protection from risks associated with biofilm formation by V. parahaemolyticus and other food pathogens.

Identification of an antivirulence agent targeting the master regulator of virulence genes in Staphylococcus aureus.

The emergence of bactericidal antibiotic-resistant strains has increased the demand for alternative therapeutic agents, such as antivirulence agents targeting the virulence regulators of pathogens. Staphylococcus aureus exoprotein expression (sae) locus, the master regulator of virulence gene expression in multiple drug-resistant S. aureus, is a promising therapeutic target. In this study, we screened a small-molecule library using a SaeRS green fluorescent protein (GFP)-reporter that responded to transcription controlled by the sae locus. We identified the compound, N-(2-methylcyclohexyl)-11-oxo-10,11-dihydrodibenzo[b,f][1,4]thiazepine-8-carboxamide (SKKUCS), as an efficient repressor of sae-regulated GFP activity. SKKUCS inhibited hemolysin production and reduced α-hemolysin-mediated cell lysis. Moreover, SKKUCS substantially reduced the expression levels of various virulence genes controlled by the master regulators, sae, and the accessory gene regulator (agr), demonstrating its potential as an antivirulence reagent targeting the key virulence regulators. Furthermore, autokinase inhibition assay and molecular docking suggest that SKKUCS inhibits the kinase activity of SaeS and potentially targets the active site of SaeS kinase, possibly inhibiting ATP binding. Next, we evaluated the efficacy and toxicity of SKKUCS in vivo using murine models of staphylococcal intraperitoneal and skin infections. Treatment with SKKUCS markedly increased animal survival and significantly decreased the bacterial burden in organs and skin lesion sizes. These findings highlight SKKUCS as a potential antivirulence drug for drug-resistant staphylococcal infections.

Molecular characterization of bovine intrauterine Escherichia coli isolates in rat model

The present study was undertaken to characterize the virulence factors of Escherichia coli isolated from bovine clinical endometritis, and comparison of uterine pathology induced by different phylogroups of E. coli in a rat model. Forty E. coli isolates assigned to different phylogroups, that is, A, B1, C, D, E, F, and clad1 were used. Phenotypic detection using Congo red binding, biofilm and haemolysin production observed 77% (n=31), 55% (n=22) and 68% (n=28) positive isolates, respectively. Multiplex PCR detection of 11 VFs genes, viz; Pap, Sfa, Afa, Hly, Cnf1, Cnf2, eaeA, F41, Sta, csgA, and csgD, found only one positive isolate each for pap and csgD while 3 isolates for F41 and 8 isolates for csgA were positive. Endometritis was inducted in diestrus rats using 4 phylogroups of E. coli. Expression for COX-2 and iNOS inflammatory marker genes was observed, but there was no statistical significant difference of expression among the phylogroups. On the basis of the present findings, it may inferred that different phylogroups of E. coli exhibit different virulence characteristics, but do not differ significantly in their ability to cause uterine disease in rats.

Molecular Assessment and Validation of the Selected Enterococcal Strains as Probiotics.

Probiotics are live microorganisms which confer health benefits to the host. Lactic acid bacteria (LAB) are used as probiotics since decades. Enterococci being the member of LAB have proven probiotic strains; therefore, this study was aimed at finding out the potential probiotic candidates from the pool of locally isolated strains. For initial screening, one hundred and twenty-two strains were selected and subjected to different confirmatory and phenotypic tests to choose the best strains that have potential probiotic criteria, i.e., no potential virulence traits, antibiotic resistance, and having tolerance properties. Keeping this criterion, only eleven strains (n = 11) were selected for further assessment. All virulence traits such as production of hemolysin, gelatinase, biofilm, and DNase were performed and not found in the tested strains. The molecular assessment indicates the presence of few virulence-associated genes in Enterococcus faecalis strains with variable frequency. The phenotypic and genotypic assessments of antibiotic resistance profile indicate that the selected strain was susceptible to ten commonly used antibiotics, and there were no transferrable antibiotic resistance genes. The presence of CRISPR-Cas genes also confirmed the absence of antibiotic resistance genes. Various enterocin-producing genes like EntP, EntB, EntA, and EntQ were also identified in the selected strains which make them promising probiotic lead strains. Different tolerance assays like acid, NaCl, and gastric juice tolerance that mimic host conditions was also evaluated by providing artificial conditions. Cellular adhesion and aggregation properties like auto- and co-aggregation were also checked and their results reflect all in the favor of lead probiotic strains.

Incidence of virulence determinants among Streptococcus agalactiae isolated from pregnant women and association with their serotypes

ABSTRACT Colonization of pregnant women by Streptococcus agalactiae (S. agalactiae) is the main reason for intrauterine infection or transmission during parturition. This study investigated the prevalence, antimicrobial susceptibility, serotypes, virulence traits of S. agalactiae in pregnant women across three hospitals in Dakahlia Governorate, Egypt. Isolates were identified by culturing onto Hichrome Sterp B selective medium, latex agglutination and biochemical tests. The antimicrobial susceptibility was determined by Kirby-Bauer disc diffusion method. Capsular serotypes were determined by latex agglutination test. Hemolysin production and biofilm formation were assessed quantitively. Virulence genes were detected by polymerase chain reaction (PCR). Among 290 samples, 31.7% were S. agalactiae. All isolates were sensitive to penicillin G, ampicillin, cefotaxime, and vancomycin, but notably resistant to tetracycline (83.6%), erythromycin (68.4%), and clindamycin (54.3%). Serotype III (26.08%) was most common. Strong biofilm was produced by 72.8% of isolates. High hemolytic activity was seen (80.4%). Prevalent virulence genes included fsbA (97.8%), fbsB (96.7%), and scpB (96.7%). rib and alp4 were frequent surface protein genes (60.8% and 57.6%, respectively). Serotypes were significantly correlated to clindamycin resistance, biofilm production (Ia, III, VI serotypes), hemolytic activity (serotype V), and several virulence genes and surface proteins. Our study found a high prevalence of S. agalactiae isolates in pregnant women with diverse resistance patterns, high virulence indicating potential for increased pathogenicity.

Description of extraintestinal pathogenic Escherichia coli based on phylogenetic grouping, virulence factors, and antimicrobial susceptibility.

Extraintestinal pathogenic Escherichia coli (ExPEC) is a recently recognized and highly diverse pathotype of E. coli. Its significance as a pathogen has increased due to the emergence of hypervirulent and multidrug-resistant (MDR) strains. The aim of this study was to characterize ExPEC isolates from humans based on their phylogenetic group, virulence factor profile, and antimicrobial susceptibility. The isolates were collected from patients with extraintestinal infections caused by E. coli, including urinary tract infections, bacteremia, and surgical site infections. The E. coli phylogenetic groups were determined using multiplex PCR. Additionally, the isolates were evaluated for their biofilm-forming abilities, susceptibility to antimicrobial agents, and presence of virulence genes. In this study, the isolates were classified into four phylogenetic groups: A (48.3%), B2 (25.8%), D (19.35%), and B1 (6.45%). All isolates exhibited at least one of the ten analyzed virulence factors. However, there was no direct evidence linking a specific phylogenetic group to a particular virulence factor. Nevertheless, the presence of the fimH, fyuA, ompT, traT, and kpsMTII virulence genes was correlated with the production of strong biofilms, multidrug resistance (MDR), and the production of alpha hemolysin. This study provides a description of the phylogenetic groups in ExPEC and their potential association with virulence factor profiles and antimicrobial susceptibility.

Characterization E. coli isolated clinical and subclinical mastitis at Ettawa-Crossbreed Goat (PE) in Yogyakarta, Indonesia

Clinical (CM) and subclinical mastitis (SCM) in Ettawa-Crossbreed goat (PE) are inflicting a financial loss. Escherichia coli (E. coli) is Gram-negative bacteria that is responsible for causing CM and SCM in goats. The purpose of this research is characterization E. coli from CM and SCM cases at PE goat in Yogyakarta, Indonesia. A total of eight E. coli isolates were obtained, with three from cases of CM and five from cases of SCM. The phenotypic characterization of E. coli involves various factors such as morphology, biochemical properties, hemolysin production, and sensitivity to antimicrobials. The study found no discernible disparities in morphology and biochemical characteristics of E. coli isolates in CM and SCM obtained from PE goats. E. coli isolates from SCM did not demonstrate hemolytic activity. However, one isolate of E. coli type ß-hemolytic was identified from CM. E. coli isolates found in CM and SCM in PE goats in Yogyakarta, Indonesia was resistant to ampicillin, erythromycin, and sulfamethoxazole. The phenotypic characterization did not differentiate between the E. coli isolates that caused CM and SCM. Therefore, it can be concluded that there are no discernible differences in the phenotypic character of E. coli isolates in CM and SCM in PE goats in Yogyakarta, Indonesia.

Comparative proteomics reveals the antibiotic resistance and virulence of Cronobacter isolated from powdered infant formula and its processing environment

Cronobacter species are opportunistic foodborne pathogens that can cause neonatal meningitis, sepsis, and necrotizing enterocolitis. In this genus, certain level strains have high mortality to infant (Cronobacter sakazakii and Cronobacter malonaticus) and antibiotic tolerance. Cronobacter has strong environmental tolerance (acid resistance, high temperature resistance, UV resistance, antibiotic resistance, etc.) and can survive in a variety of environments. It has been isolated in various production environments and products in several countries. However, the relationships between Cronobacter antibiotic tolerance and virulence remain unclear, especially at the molecular level. In this study, 96 strains of Cronobacter were isolated from powdered infant formula and its processing environment and screened for antibiotic tolerance, and proteomic maps of the representative strains of Cronobacter with antibiotic tolerance were generated by analyzing proteomics data using multiple techniques to identify protein that are implicated in Cronobacter virulence and antibiotic resistance. The increase in antibiotic tolerance of Cronobacter had a certain increase in the production of enterotoxin and hemolysin. Only triple tolerated Cronobacter sakazakii decreased the utilization of sialic acid. A total of 16,131 intracellular proteins were detected in eight representative strains, and different proteomes were present in strains with different antibiotic tolerance, including 56 virulence-related proteins. Multiple virulence proteins regulated by unknown genes were also found in the eight isolated representative strains.