Coagulase Activity Research Articles

Evaluation of anti-biofilm and anti-virulence effect of zinc sulfate on Staphylococcus aureus isolates

Staphylococcus aureus produces a plethora of virulence factors to invade and establish infections in the host system, and biofilms are more resistant to antibiotics than planktonic cells. In this study, we aimed to investigate the anti-virulence and anti-biofilm potentials of zinc sulfate against S. aureus isolates. The synergistic effect of zinc sulfate in combination with antibiotics on S. aureus was characterized using the checkerboard method. The influence of zinc sulfate on biofilm formation and virulence factors production by S. aureus was experimentally assessed. RT-qPCR was used to investigate the effect of zinc sulfate on the expression of biofilm-related genes. Zinc sulfate exhibited good antibacterial activity against S. aureus with a MIC of 128 µg/ml against all tested isolates. Also, the findings indicate a synergistic effect of a combination of zinc sulfate and antibiotics against the tested isolates. Zinc sulfate at 256 µg/ml concentration inhibited biofilm formation for all isolates. The expression of biofilm-related genes was significantly repressed in zinc sulfate-treated bacteria compared to untreated cells. Zinc sulfate could inhibit the hemolytic ability of S. aureus. Moreover, zinc sulfate-treated bacteria exhibited a significant decrease in coagulase and catalase activity relative to control untreated S. aureus. Our results support that zinc sulfate is a potential antimicrobial and anti-virulence agent against S. aureus infections.

Evaluation of virulence determinants and cell surface properties associated with biofilm formation in methicillin-resistant Staphylococcus aureus (MRSA) and extended spectrum beta-lactamase (ESBL) Escherichia coli from livestock and poultry origin

Antibiotic resistance poses a persistent threat to modern medicine due to the emergence of novel antibiotic-resistant strains. Therefore, a timely understanding of antibiotic resistance and the virulence biology of pathogenic bacteria, particularly those of public health significance, is crucial for implementing effective mitigation strategies. This study aimed to investigate the virulence profiles of ten S. aureus isolates (NDa to NDj) and ten E. coli isolates (ND1 to ND10) originating from livestock and poultry, and to assess how various cell surface properties and biofilm formation abilities influence antibiotic resistance phenotypes. Antibiotic resistance profiling through phenotypic (AST) and genotypic methods (PCR) confirmed that NDa to NDe were methicillin-resistant S. aureus (MRSA) and ND1 to ND5 were extended-spectrum β-lactamase (ESBL) producing E. coli isolates. Virulence properties such as hemolytic activity, coagulase activity, and nuclease activity were found to be independent of the antibiotic resistance phenotype in S. aureus. In contrast, biofilm formation phenotype was observed to influence antibiotic resistance phenotypes, with MRSA and ESBL E. coli isolates demonstrating higher biofilm formation potency. Chemical and enzymatic analysis of S. aureus and E. coli biofilms revealed proteins and polysaccharides as major components, followed by nucleic acids. Furthermore, cell surface properties such as auto-aggregation and hydrophobicity were notably higher in isolates with strong to medium biofilm-forming capabilities (ESBL and MRSA isolates), corroborated by genomic confirmation of various genes associated with biofilm, adhesion, and colonization. In conclusion, this study highlights that surface hydrophobicity and biofilm formation ability of MRSA (NDa to NDe) and ESBL E. coli (ND1 to ND5) isolates may influence antibiotic resistance phenotypes.

Evaluation of Epidemiological Pattern of Candida Species Associated with Candidemia from A Tertiary Care Facility in South India

Candidemia ranks the 4th most prevalence cause of bloodstream infections and stands out as the primary cause of invasive fungal infections among hospitalized patients. Its incidence varies globally from 0.33 to 6.51 episodes per 1000 admissions, representing a major public health burden due to its increasing incidence and high mortality rates. The present research work has been conducted to identify the distribution of Candida species among septicemic patients and to determine the patterns of antifungal susceptibility of Candida species isolates from them in a tertiary care center in South India. Among the 88 Candida isolates, 13 (14.8%) were speciated and identified as C. albicans and 75 (85.2%) were Candida non-albicans. Of them, C. tropicalis (42%) ranks more prevalent. The distribution of virulence factors among 88 Candida isolates revealed that 49 isolates (55.7%) exhibited phospholipase activity, hemolysin production was detected in 68.2% of isolates, biofilm production was demonstrated in 73.9% isolates and coagulase activity was observed in 46.7% isolates. In the present study, Candida species were most sensitive to Amphotericin B (94.3%), which is followed by Caspofungin (93.2%), Voriconazole (92%), Micafungin (90.9%), and the least was observed with Flucytosine (78.4%) and Fluconazole (71.5%). Thus, in order to improve treatment responses, the insights acquired from this research will aid in clinical management and the development of antifungal stewardship recommendations.

Comparative Antimicrobial Resistance and Prevalence of Methicillin Resistance in Coagulase-Positive Staphylococci from Conventional and Organic Dairy Farms in South Korea.

Bovine mastitis (BM) has caused huge economic and financial losses in the dairy industry worldwide, with Staphylococcus aureus as one of its major pathogens. BM treatment still relies on antibiotics and its extensive use often generates methicillin-resistant S. aureus (MRSA) and mupirocin-resistant S. aureus (MuRSA). This study compared the antimicrobial resistance trend in coagulase-positive Stapholococci (CoPS) isolated from BM milk in conventional and organic dairy farms and checked prevalence of MRSA and MuRSA. A total of 163 presumptive Staphylococci were isolated, wherein 11 out of 74 from 4 conventional farms (CF1, CF2, CF3, CF4) and 17 out of 89 from 3 organic farms (OF1, OF2, OF3) exhibited coagulase activity. Multiplex-PCR amplification confirmed at least one coagulase-positive isolate from CF1, CF2, CF3, CF4, and OF1 as S. aureus, denoted by the presence of the nuc gene. Three isolates from CF2 contained the mecA gene, indicating MRSA prevalence, while the MuRSA gene marker, mupA, was not detected in any of the isolates. Antimicrobial testing showed that conventional farm isolates were more resistant to antibiotics, especially ampicillin and tetracycline. This suggests a risk of developing multidrug resistance in dairy farms if antibiotic use is not properly and strictly monitored and regulated.

Restraining Staphylococcus aureus Virulence Factors and Quorum Sensing through Lactic Acid Bacteria Supernatant Extracts.

The escalating prevalence of antibiotic-resistant bacteria poses a grave threat to human health, necessitating the exploration of novel alternatives to conventional antibiotics. This study investigated the impact of extracts derived from the supernatant of four lactic acid bacteria strains on factors contributing to the pathogenicity of three Staphylococcus aureus strains. The study evaluated the influence of lactic acid bacteria supernatant extracts on the growth, biofilm biomass formation, biofilm metabolic activity, and biofilm integrity of the S. aureus strains. Additionally, the impact on virulence factors (hemolysin and coagulase) was examined. Gas chromatography coupled with mass spectrometry was used to identify the bioactive compounds in the extracts, while molecular docking analyses explored potential interactions. Predominantly, the extracts contain eight 2,5-diketopiperazines, which are cyclic forms of peptides. The extracts demonstrated inhibitory effects on biofilm formation, the ability to disrupt mature biofilms, and reduce the biofilm cell metabolic activity of the S. aureus strains. Furthermore, they exhibited the ability to inhibit α-hemolysin production and reduce coagulase activity. An in silico docking analysis reveals promising interactions between 2,5-diketopiperazines and key proteins (SarA and AgrA) in S. aureus, confirming their antivirulence and antibiofilm activities. These findings suggest that 2,5-diketopiperazines could serve as a promising lead compound in the fight against antibiotic-resistant S. aureus.

Evaluation of Bacillus isolates as a biological control agents against soilborne phytopathogenic fungi.

Pesticides, used in agriculture to control plant diseases, pose risks to the environment and human health. To address this, there's a growing focus on biocontrol, using microorganisms instead of chemicals. In this study, we aimed to identify Bacillus isolates as potential biological control agents. We tested 1574 Bacillus isolates for antifungal effects against pathogens like Botrytis cinerea, Fusarium solani, and Rhizoctonia solani. Out of these, 77 isolates formed inhibition zones against all three pathogens. We then investigated their lytic enzyme activities (protease, chitinase, and chitosanase) and the production of antifungal metabolites (siderophore and hydrogen cyanide). Coagulase activity was also examined to estimate potential pathogenicity in humans and animals. After evaluating all mechanisms, 19 non-pathogenic Bacillus isolates with significant antifungal effects were chosen. Molecular identification revealed they belonged to B. subtilis (n = 19) strains. The 19 native Bacillus strains, demonstrating strong antifungal effects in vitro, have the potential to form the basis for biocontrol product development. This could address challenges in agricultural production, marking a crucial stride toward sustainable agriculture.

Distinguishing characteristics of Staphylococcus schleiferi and Staphylococcus coagulans of human and canine origin.

Staphylococcus schleiferi and Staphylococcus coagulans are opportunistic pathogens of animals and humans. They were previously classified as Staphylococcus schleiferi subs. schleiferi and Staphylococcus schleiferi subs. coagulans, respectively, and recently reclassified as separate species. S. coagulans, is frequently associated with dogs, whereas S. schleiferi is more commonly isolated from humans. Coagulase activity status is a defining characteristic of the otherwise closely related species. However, the use of coagulase tests originally developed to distinguish S. aureus from non-coagulase-producing staphylococci, for this purpose is questionable and the basis for their host preference has not been elucidated. In the current study, a putative coa gene was identified and correlated with coagulase activity measured using a chromogenic assay with human and bovine prothrombin (closely related to canine prothrombin). The results of the tests performed with human prothrombin showed greater reactivity of S. coagulans isolates from humans than isolates obtained from dogs with the same substrate. Our data suggest that unlike S. coagulans isolates from humans, isolates from dogs have more coagulase activity with bovine prothrombin (similar to canine prothrombin) than human prothrombin. Differences in nuc and 16s rRNA genes suggest a divergence in S. coagulans and S. schleiferi. Phenotypic and genotypic variation based on the number of IgG binding domains, and the numbers of tandem repeats in C-terminal fibronectin binding motifs was also found in protein A, and fibronectin-binding protein B respectively. This study identified a coa gene and associated phenotypic activity that differentiates S. coagulans and S. schleiferi and identified key phylogenetic and phenotypic differences between the species.

Pathogenic potential of Staphylococcus aureus strains isolated from unpackaged ice cream samples sold in Istanbul

Ice cream is a widely consumed refreshing food, especially in the summer months, and it creates a suitable environment for microbial growth due to its high nutritional value, appropriate pH, and long storage time. This study aimed to evaluate the incidence of enterotoxigenic and meticillin-resistant Staphylococcus aureus in unpackaged ice cream samples sold in Istanbul, Turkey. For that purpose, 101 unpackaged ice cream samples were collected and evaluated for coagulase activity, DNase activity, and methicillin resistance. Staphylococcus aureus is determined in 66 (65.3%) samples with a mean load of 3.2±1.0 log cfu/mL. 34.6% of samples exceeded the Turkish Food Codex (2009) limit, which ranged between 102 – 103 cfu/g. It was found that 61 (64.8%) of the S. aureus strains were coagulase positive, 21 (22.3%) were DNase positive, and 18 (19.1%) had methicillin resistance. The present study's findings revealed that unpackaged ice cream samples in Istanbul have high enterotoxin-producing potential with a high S. aureus load. The presence of Methicilin-resistant strains may represent a potential hazard to public health.

Microbiological Characteristics of Clinically Isolated Staphylococcus aureus with Different Hemolytic Phenotypes in China.

This study aimed to investigate the microbiological characteristics of clinically isolated Staphylococcus aureus with different hemolytic phenotypes in China. Using the three-point inoculation method, the hemolytic phenotypes of 1295 clinically isolated S. aureus strains were detected and categorized. Antimicrobial susceptibility testing of all strains was performed using a VITEK 2 Compact System. After sample size matching, plasma coagulase activity, catalase activity, mRNA expression of hemolysin genes (hla, hlb, hlc, and hld), biofilm formation, growth kinetics, inflammatory response of macrophages and cytotoxicity of S. aureus with different hemolytic phenotypes using the rabbit plasma kit, the catalase test on slides, qRT-PCR, crystal violet staining, the microcultivation assay, the ELISA kits, and the CCK-8 assay, respectively. Seven categories of hemolytic phenotypes were identified. Accordingly, strains were categorized into seven different groups, including S. aureus with complete hemolytic phenotype (SCHP), S. aureus with weak hemolytic phenotype (SWHP), S. aureus with incomplete hemolytic phenotype 1 (SIHP-1), SIHP-2, SIHP-3, SIHP-4 and SIHP-5, the last three of which were reported for the first time. Except for the hemolytic phenotype, all seven groups differed in clinical isolation rates, antibiotic resistance profile, plasma coagulase activity, mRNA expression of hemolysin genes, biofilm formation, growth kinetics, inflammatory response of macrophages, and cytotoxicity. S. aureus with different hemolytic phenotypes have distinctive microbiological characteristics. Clinical microbiologists need to be vigilant about the hemolytic phenotypes when culturing S. aureus strains, and actively enhance communication with clinicians to optimize the treatment of infection.

Detection of Staphylococci from nasal samples from healthy and sick dogs in Ho Chi Minh City, Vietnam

Staphylococci are one of the most commonly found opportunistic bacteria in animals and human. The objective of this study was to determine the prevalence of Staphylococcus spp. isolated from healthy and sick dogs visiting veterinary clinics in Ho Chi Minh city, Vietnam from January 2022 to December 2022. A total of 123 nasal swab samples were collected, including 40 samples from healthy dogs and 83 samples from dogs with respiratory symptoms. Staphylococcus spp. were isolated from 47.5% of healthy animals and 60.24% of dogs showing respiratory symptoms. The study showed that isolation rates from confined, semi-confined and free-ranging dogs were 75.86%, 54.84% and 40.63%, respectively. Furthermore, the prevalence was higher in dogs over one year old compared to younger dogs (64.10% and 42.22%, respectively). Several subspecies of Staphylococci, including S. aureus, S. pseudintermedius and S. epidermidis were identified, in which S. pseudintermedius accounted for the highest proportion (48.28%). The prevalence of S. pseudintermedius also varied across different age groups. Coagulase activity of the isolated Staphylococcus strains was also determined and indicated that coagulase-positive Staphylococci constituted 80.46% of the isolates. This study represents the first report on the prevalence of Staphylococci in dogs in Vietnam and reemphasizes the zoonotic significance of Staphylococcus at the interface between dogs and humans.

Prevalence of Coagulase Negative Strains of Staphylococcus aureus in Clinical Specimens at the University of Benin Teaching Hospital, Benin City, Nigeria

The test for coagulase activity is a simple and non-expensive test for the identification of S. aureus strains from clinical samples in resource-poor settings. The results of these tests have been reported to vary with the source of plasma and with some atypical strains that test negative with the coagulase test. The study was carried out to determine if misidentification of strains of S. aureus exists on account of the reliance on the coagulase tests. Clinical isolates of Staphylococci that tested negative by the coagulase tests from wounds, pus, aspirates, blood cultures and urogenital samples were collected and re-tested by the slide and tube coagulase tests and confirmed to be negative. Each isolate was inoculated onto mannitol sat agar and DNAse agar plates and incubated at 37oC for 18 h. Isolates that fermented mannitol and showed a positive DNAse test were 25/366 (6.8%). The highest number of coagulase-negative Staphylococcus aureus (CNSA) occurred within blood culture samples 25.7% and in wound, pus and aspirates, 6.9% and the least proportion, 2.9% from urogenital samples. The generation of CNSA strains is strongly associated with severely-ill patients and the potential for the administration of cell-wall inhibiting antibacterial agents may have important roles to play in the emergence CNSA. The inclusion of DNAse test in the routine identification of staphylococci is advocated especially when an isolate has tested coagulase-negative.

Mineral Solubilizing Rhizobacterial Strains Mediated Biostimulation of Rhodes Grass Seedlings.

Minerals play a dynamic role in plant growth and development. However, most of these mineral nutrients are unavailable to plants due to their presence in fixed forms, which causes significant losses in crop production. An effective strategy to overcome this challenge is using mineral solubilizing bacteria, which can convert insoluble forms of minerals into soluble ones that plants can quickly assimilate, thus enhancing their availability in nutrient-depleted soils. The main objective of the present study was to isolate and characterize mineral solubilizing rhizobacteria and to assess their plant growth-promoting potential for Rhodes grass. Twenty-five rhizobacterial strains were isolated on a nutrient agar medium. They were characterized for solubilization of insoluble minerals (phosphate, potassium, zinc, and manganese), indole acetic acid production, enzymatic activities, and various morphological traits. The selected strains were also evaluated for their potential to promote the growth of Rhodes grass seedlings. Among tested strains, eight strains demonstrated strong qualitative and quantitative solubilization of insoluble phosphate. Strain MS2 reported the highest phosphate solubilization index, phosphate solubilization efficiency, available phosphorus concentration, and reduction in medium pH. Among tested strains, 75% were positive for zinc and manganese solubilization, and 37.5% were positive for potassium solubilization. Strain MS2 demonstrated the highest quantitative manganese solubilization, while strains MS7 and SM4 reported the highest solubilization of zinc and potassium through acidifying their respective media. The strain SM4 demonstrated the most increased IAA production in the presence and absence of L-tryptophan. The majority of strains were positive for various enzymes, including urease, catalase protease, and amylase activities. However, these strains were negative for coagulase activity except strains SM7 and MS7. Based on 16S rRNA gene sequencing, six strains, namely, SM2, SM4, SM5, MS1, MS2, and MS4, were identified as Bacillus cereus, while strains SM7 and MS7 were identified as Staphylococcus saprophyticus and Staphylococcus haemolyticus. These strains significantly improved growth attributes of Rhodes grass, such as root length, shoot length, and root and shoot fresh and dry biomasses compared to the uninoculated control group. The present study highlights the significance of mineral solubilizing and enzyme-producing rhizobacterial strains as potential bioinoculants to enhance Rhodes grass growth under mineral-deficient conditions sustainably.

Inhibitory Effect of Salicin on Staphylococcus aureus Coagulase.

The massive use of antibiotics has resulted in an alarming increase in antibiotic resistance in Staphylococcus aureus (S. aureus). This study aimed to identify the inhibitory effect of salicin on S. aureus. Coagulase (Coa) activity was assessed using in vitro Coa assays and Western blot, thermal shift assay (TSA), fluorescence quenching and molecular docking experiments were conducted to verify the interaction between salicin and Coa. An in vivo mouse pneumonia model demonstrated that salicin can reduce the virulence of S. aureus. In vitro Coa assays elucidated that salicin directly inhibited Coa activity. The Western blot and TSA results suggested that salicin did not block the expression of Coa but affected the thermal stability of the protein by binding to Coa. The fluorescence quenching, molecular docking and molecular dynamics assays have found that the most promising binding site between salicin and Coa was GLN-97. The pneumonia model of mice infected with S. aureus revealed that salicin could not only reduce the content of lung bacteria in mice but also prolong their survival. Salicin was identified as a novel anti-infective candidate compound with the potential to target Coa and inhibit its activity by binding to it, which would facilitate the development of roadmaps for future research.

The Contribution of Curable Plasmid-Mediated Resistance in Isolates of Staphylococcus aureus at the University of Benin Teaching Hospital, Benin City, Nigeria

aureus, is an important human pathogen and commensal that is responsible for infections ranging from minor to deep-seated life-threatening conditions. Multi-drug resistant S. aureus or MRSA is a major cause of hospital acquired infection (HAIs) or nosocomial infections with consequential reduction in treatment options and overtly increased cost of healthcare, morbidity and mortality. The study was conceived to determine the contribution of curable transmissible plasmids to the ever-increasing proportion of multi-drug resistant S. aureus at the University of Benin Teaching Hospital, Benin City. A total of 448 consecutive multi-drug resistant clinical isolates of S. aureus were collected, confirmed by SCT and TCT and resistance to commonly used antimicrobial agents. Each isolate was inoculated into Mueller-Hinton Broth containing 100 µg/mL acridine orange and incubated at 37oC for 24 h. Each broth culture was subsequently sub-cultured onto blood agar plates and incubated at 37oC for 24 h. Sensitivity tests were thereafter done on each sub-culture by the Kirby-Bauer disc diffusion method. SCT and TCT were re-tested on each sub-culture. Isolates with curable transmissible plasmids were 31/448(6.9%) and there was complete reversion to sensitivity in all the cured strains to antimicrobial agents tested including ampicillin. The remaining isolates (93.1%) retained their resistance to all the antimicrobial agents. The isolates with curable plasmids (6.9%) also lost the coagulase activity of both types. Plasmid-mediated resistance in S. aureus remain an important route of multi-drug resistance, however this is dwarfed by chromosomally-mediated resistance as the major mechanism of resistance in multi-drug resistance S. aureus. Additionally, the cure of drug resistance was also concomitantly associated with lose of the pathogenicity factor-coagulase in these isolates. Keywords: S. aureus, multi-drug resistance, transmissible plasmids.

Mycological Profile of Candida tropicalis and its Virulence Factors from Candidemia Patients at A Tertiary Care Facility

Candida tropicalis is the fourth main infective agent of Candida species in several developing nations and leads to the greatest fatality rate among the non-albicans Candida (NAC) species that cause candidemia. Seventy clinically known Candida isolates are isolated in positively flagged blood samples from BacT/ALERT 3D from various wards. Virulence factors like hemolysin production, coagulase activity, phospholipase activity, and biofilm formation were studied and antifungal susceptibility testing was and Minimum Inhibitory Concentration (MIC) values were interpreted. Of the total 70 clinical Candida isolates, the most predominant organism isolated was found to be C. tropicalis 27 (38.57%) which is succeeded by 19 (27.14%) C. albicans, 13 (18.57%) C. parapsilosis, 6 (8.57%) C. glabrata, and 5 (7.14%) C. krusei respectively. Among the70 Candida isolates, 49 (70%) showed hemolysin production, 43 (61.42%) isolates demonstrated phospholipase activity, 34 (48.57%) showed coagulase activity and 55 (78.57%) isolates showed biofilm production by crystal violet assay. A high level of Fluconazole resistance has been observed in 23 (32.85%) Candida isolates in comparison with other antimicrobials utilized in this study. The higher MIC value of: ≥ 64 µg/mL Fluconazole was shown by 4 (57.14%) isolates of C. tropicalis by broth microdilution method. The interpretation of various virulence factors and antifungal drug resistance were seen mostly among NAC species, thus hence signifying its pivotal role in immunocompromised individual treatment.

In Vitro Detection of Virulence Factors of Candida albicans & non-albicans Candida species Isolated from the Samples in ICU Patients

Aim: To isolate and identify Candida albicans and non-albicans Candida from various clinical specimen of Intensive care Unit and to investigate some virulence factors and perform their Anti- fungal susceptibility. Materials and Methods: Overall 32 isolates (12 Candida albicans and 20 non- albicans Candida spp.) were included in this study. Virulence factors were studied. In isolates, egg yolk agar was used for determining phospholipase activity, while sheep and human plasma used to determine coagulase activity, Sabouraud dextrose agar with sheep blood for hemolysin activity. Biofilm formation was detected by the tube adherence method. Results: In both Candida spp., it was found that hemolytic activity were higher next to phospholipases activity. It was also found that Coagulase activity were detected in Candida species found to be higher with sheep plasma compared to human plasma. Biofilm production was found to be less and mostly were from blood culture isolates. Conclusion: Knowledge of these virulence factors is an important tool to understand pathogenesis of candidiasis and in addition will help to explore new antifungal drug targets for improved therapeutic regimens.

The production and influence of anti-Vibrio parahaemolytics IgY against experimental infection of V. parahaemolyticus in cultured Fenneropenaeus indicus

The increasing number of antibiotic-resistant bacteria emphasizes the need to find alternatives to complement antibiotics. Immunotherapy may also be used as a complementary treatment against pathogens that are difficult to treat with traditional antibiotics. Eggs are normal dietary components and there is practically no risk of toxic side effects of IgY given orally. In the present study, pathogenic Vibrio parahaemolyticus was isolated from infected shrimp and studied their virulence factors including LD50 (by challenging with Fenneropenaeus indicus), proteolytic and hemolytic activities. The edible antibody IgY was raised by injecting the antigen of Extra Cellular Products (ECP) of V. parahaemolyticus to Gallus gallus domesticus during layoff period with and without the herbal immunoadjuvants, Asparagus racemosus and Glycine max (V.p wo: V. parahaemolyticus ECP without adjuvant; V.p A: V. parahaemolyticus ECP with A. racemosus and V.p G: V. parahaemolyticus ECP with G. max). Eggs were collected after five weeks of immunization and anti- V. parahaemolyticus IgY was extracted and purified. Physicochemical properties of the immunized Chickens' serum and anti- V. parahaemolyticus IgY's cross reactivity, growth inhibition assay, single radial immunodiffusion assay and bacterial agglutination were studied. The results revealed that, the serum protein parameters were significantly (P ≤ 0.001) increased in experimental groups from control group. The antibody raised with immunoadjuvants had significantly (P ≤ 0.001) higher cross reactivity, growth inhibition, single radial immunoassay and bacterial agglutination when compared with and without immunoadjuvant and control groups. Further the control and experimental anti-V. parahaemolytics IgY coated artificial diets were fed to F. indicus for 60 days. After 30 and 60 dpv (days of post vaccination), shrimps from each groups were challenged with virulent V. parahaemolyticus and studied the survival, haematological and immunological parameters. The IgY coated diets (V. p A and V.p G) fed shrimps had decreased cumulative mortality, significantly (P ≤ 0.001) improved coagulase activity, total haemocyte count and oxyhaemocyanin. The immunological parameters such as prophenoloxidase, intracellular anion production, lysozyme production and phagocytosis also improved significantly (P ≤ 0.001) in IgY treated shrimps.

Transcriptomic and Metabolomic Analysis of a Fusidic Acid-Selected fusA Mutant of Staphylococcus aureus.

Physiological experimentation, transcriptomics, and metabolomics were engaged to compare a fusidic acid-resistant Staphylococcus aureus mutant SH10001st-2 to its parent strain SH1000. SH10001st-2 harbored a mutation (H457Y) in the gene fusA which encodes the fusidic acid target, elongation factor G, as well as mutations in a putative phage gene of unknown function. SH10001st-2 grew slower than SH1000 at three temperatures and had reduced coagulase activity, two indicators of the fitness penalty reported for fusA-mediated fusidic acid- resistance in the absence of compensatory mutations. Despite the difference in growth rates, the levels of O2 consumption and CO2 production were comparable. Transcriptomic profiling revealed 326 genes were upregulated and 287 were downregulated in SH10001st-2 compared to SH1000. Cell envelope and transport and binding protein genes were the predominant functional categories of both upregulated and downregulated genes in SH10001st-2. Genes of virulence regulators, notably the agr and kdp systems, were highly upregulated as were genes encoding capsule production. Contrary to what is expected of mid-exponential phase cells, genes encoding secreted virulence factors were generally upregulated while those for adhesion-associated virulence factors were downregulated in SH10001st-2. Metabolomic analysis showed an overall increase in metabolite pools in SH10001st-2 compared to SH1000, mostly for amino acids and sugars. Slowed growth and metabolite accumulation may be byproducts of fusA mutation-mediated protein synthesis impairment, but the overall results indicate that SH10001st-2 is compensating for the H457Y fitness penalty by repurposing its virulence machinery, in conjunction with increasing metabolite uptake capacity, in order to increase nutrient acquisition.

Detection of Resistant and Enterotoxigenic Strains of Staphylococcus warneri Isolated from Food of Animal Origin.

The topic of this work is the detection of antimicrobial resistance to Staphylococcus warneri strains and the genes encoding staphylococcal enterotoxins. It is considered a potential pathogen that can cause various—mostly inflammatory—diseases in immunosuppressed patients. The experimental part of the paper deals with the isolation of individual isolates from meat samples of Oryctolagus cuniculus, Oncorhynchus mykiss, Scomber scombrus, chicken thigh, beef thigh muscle, pork thigh muscle, and bryndza cheese. In total, 45 isolates were obtained and subjected to phenotypic (plasma coagulase activity, nuclease, pigment, hemolysis, lecithinase, and lipase production) and genotypic analyses to confirm the presence of the S. warneri species. The presence of genes encoding staphylococcal enterotoxins A (three isolates) and D (six isolates) was determined by PCR. Using the Miditech system, the minimum inhibitory concentration for various antibiotics or antibiotics combinations was determined, namely for ampicillin; ampicillin + sulbactam; oxacillin; cefoxitin; piperacillin + tazobactam; erythromycin; clindamycin; linezolid; rifampicin; gentamicin; teicoplanin; vancomycin; trimethoprim; chloramphenicol; tigecycline; moxifloxacin; ciprofloxacin; tetracycline; trimethoprim + sulfonamide; and nitrofurantoin. Resistance to ciprofloxacin and tetracycline was most common (73%). At the same time, out of a total of 45 isolates, 22% of the isolates were confirmed as multi-resistant. Isolates that showed phenotypic resistance to β-lactam antibiotics were subjected to mecA gene detection by PCR.

Isolation and identification of lactic acid bacteria in fruit processing residues from the Brazilian Cerrado and its probiotic potential

Fruit residues may contain lactic acid bacteria (LAB) with probiotic properties. This study aimed to isolate, characterize and identify LAB isolated from Brazilian Cerrado fruit residues, as well as to evaluate the safety and functionality properties in vitro. Twenty colonies were isolated and characterized. Biochemical and morphological analyses showed 14 LAB isolates, which were identified by sequencing the 16S rRNA gene in Lactiplantibacillus plantarum/pentosus, Lacticaseibacillus casei/paracasei, Pediococcus adicilactici and Weissella cibaria/confusa. Most of the isolates showed susceptibility to antibiotics and none showed hemolytic, gelatinase, coagulase, and DNAse activity. At pH 2, the survival of most strains examined was reduced after 3h exposure -. Four showed a survival rate similar to control, while L. casei/paracasei from guapeva fruit showed a higher rate. 11 isolates inhibited the growth of Esherichia coli, Staphylococcus aureus and Salmonella sp. Cluster analysis grouped the isolates according to similarity. The results highlight the specificity of the food matrix, genus, species and strain, however selected LAB strains can be submitted for further investigation of new probiotic strains.