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ABSTRACT In response to the heightened risk of bacterial diseases in fish farms caused by increased demand for fish consumption and subsequent overcrowding, researchers are currently investigating the efficacy and residue management of oxolinic acid (OA) as a treatment for bacterial infections in fish. This research is crucial for gaining a comprehensive understanding of the pharmacokinetics of OA. The present study investigates pharmacokinetics of OA in juvenile rainbow trout. The fish were given a 12 mg kg−1 dose of OA through their feed, and tissue samples were collected of the liver, kidney, gill, intestine, muscle, and plasma for analysis using LC‐MS/MS. The highest concentrations of the drug were found in the gill (4096.55 μg kg−1) and intestine (11592.98 μg kg−1), with significant absorption also seen in the liver (0.36 L/h) and gill (0.07 L/h) (p < 0.05). The liver (0.21 L/h) and kidney (0.03 L/h) were found to be the most efficient (p < 0.05) at eliminating the drug. The study also confirmed the drug antimicrobial effectiveness against several bacterial pathogens, including Shewanella xiamenensis (0.25 μg mL−1), Lactococcus garvieae (1 μg mL−1), and Chryseobacterium aquaticum (4 μg mL−1). The study concludes significant variations among different fish tissues, with higher concentrations and longer half‐lives observed in the kidney and intestine. The lowest MIC value recorded against major bacterial pathogens demonstrated its therapeutic potential in aquaculture. It also emphasizes the importance of understanding OA pharmacokinetics to optimize antimicrobial therapy in aquaculture. [ABSTRACT FROM AUTHOR]

In this study, six isolates of Chryseobacterium balustinum were characterized from diseased rainbow trout fingerlings. The virulence characteristics, pathogenicity, and antimicrobial susceptibility pattern of these isolates were investigated. The bacterium showed positive results for catalase, cytochrome oxidase, and aesculin hydrolysis, while negative results were obtained for DNase, gelatinase, methyl red, Voges-Proskauer's reaction, Simon citrate, Hydrogen sulphide, and starch hydrolysis. Amino acid metabolism analysis revealed the inability to metabolize arginine, lysine, and ornithine decarboxylase. Molecular characterization (16S rRNA) and phylogenetic analysis revealed the test isolates as C. balustinum, closely related to strain WLT (99.85% similarity) and C. balustinum P-27 (99.77%). Virulence assay indicated haemolytic activity and biofilm formation by the test bacterium. The challenge test confirmed moderate pathogenicity in rainbow trout and established Koch's postulates. The clinical manifestations of infection included fin erosion, eye and body surface haemorrhage, exophthalmia, and organ liquefaction. The minimum inhibitory concentrations of various antimicrobials ranged from 1 to > 256 µg mL−1. The novel synthetic antimicrobial peptides exhibited MICs of 8 to > 256 µg mL−1, suggesting a potential control method. These findings suggest that C. balustinum is an opportunistic pathogen with moderate pathogenicity in rainbow trout. Further research on the host–pathogen relationship is necessary to understand virulence characteristics and pathogenicity in aquaculture. [ABSTRACT FROM AUTHOR]

In this study, six isolates of Chryseobacterium balustinum were characterized from diseased rainbow trout fingerlings. The virulence characteristics, pathogenicity, and antimicrobial susceptibility pattern of these isolates were investigated. The bacterium showed positive results for catalase, cytochrome oxidase, and aesculin hydrolysis, while negative results were obtained for DNase, gelatinase, methyl red, Voges-Proskauer's reaction, Simon citrate, Hydrogen sulphide, and starch hydrolysis. Amino acid metabolism analysis revealed the inability to metabolize arginine, lysine, and ornithine decarboxylase. Molecular characterization (16S rRNA) and phylogenetic analysis revealed the test isolates as C. balustinum, closely related to strain WLT (99.85% similarity) and C. balustinum P-27 (99.77%). Virulence assay indicated haemolytic activity and biofilm formation by the test bacterium. The challenge test confirmed moderate pathogenicity in rainbow trout and established Koch's postulates. The clinical manifestations of infection included fin erosion, eye and body surface haemorrhage, exophthalmia, and organ liquefaction. The minimum inhibitory concentrations of various antimicrobials ranged from 1 to > 256 µg mL−1. The novel synthetic antimicrobial peptides exhibited MICs of 8 to > 256 µg mL−1, suggesting a potential control method. These findings suggest that C. balustinum is an opportunistic pathogen with moderate pathogenicity in rainbow trout. Further research on the host–pathogen relationship is necessary to understand virulence characteristics and pathogenicity in aquaculture. [ABSTRACT FROM AUTHOR]

The biofilm‐forming ability of microbes is often correlated with drug resistance; however, this association among enteroaggregative Escherichia coli (EAEC) strains remains naïve. Moreover, the investigations exploring uptake and assimilation of sugars either qualitatively or quantitatively by the biofilm‐forming EAEC strains have not yet been documented. Hence, this study investigated the role of various categories of sugars (monosaccharides, disaccharides, and polysaccharide) on the biofilm‐forming ability of three each of multi‐drug‐resistant (MDR) as well as non‐MDR typical EAEC strains. The EAEC strains exhibited black colonies on congo red agar (CRA) with monosaccharides and disaccharides, whereas all the strains exhibited red colonies on CRA with the polysaccharide. Although significant (p < 0.001) biofilm‐forming ability was observed by all the EAEC strains in sugar‐dependent microtiter plate assay, color change from pink to orange and yellow was noticed in presence of monosaccharides and disaccharide, while absent in polysaccharides. Besides, significantly higher bacterial counts were observed in presence of monosaccharides and disaccharides (p < 0.01); however, such significant bacterial counts were not noticed with the polysaccharide. Further, the real‐time PCR data exhibited comparatively higher relative expression of biofilm‐associated fis gene among EAEC strains grown in presence of monosaccharides, followed by disaccharide and polysaccharide, respectively that concurred with the flow cytometry data. No significant (p > 0.05) difference was observed in the biofilm‐forming ability between MDR‐ and non‐MDR EAEC strains. This study illustrated the role of carbohydrates on the biofilm‐forming ability of EAEC and warranted utmost attention concerning the usage of carbohydrates in food processing industries, for its incorporation as functional food additives. [ABSTRACT FROM AUTHOR]

We explored and evaluated for the first time colorimetric nitrocefin assay in conjunction with the double disc test and PCR assay. We suggested the use of nitrocefin assay for rapid screening of ESBL-production by Enteroaggregative Escherichia coli. [ABSTRACT FROM AUTHOR]

There have been few studies examining the outcome of schizophrenia in later life. Using five conceptual models, we test two hypotheses with respect to range of outcomes among older schizophrenia outpatients and how they compare to their age peers in the community. We operationalized five outcome measures from the following conceptual models: Remission, adapting criteria of Andreasen et al. (The American Journal of Psychiatry, 162:441–449, 2005); Recovery, adapting the criteria by Liberman et al. (International Review of Psychiatry, 14:256–272, 2002); Community Integration using the model of Wong and Solomon (Mental Health Services Research, 4:13–28, 2002); Subjective and Objective Successful Aging using the model of Rowe and Kahn (Science, 237:143–149, 1987). The schizophrenia (S) group consisted of 198 community-dwelling persons aged 55 and over who developed schizophrenia before age 45 and a community comparison (CC) group ( N = 113). Remission and recovery criteria were met by 49 and 17% of the S group, respectively. There were significant differences between the S and CC groups in the distribution of community integration and successful aging scales: 41% of the CC group met at least 10 of 12 criteria versus 23% of the S group on the Community Integration Scale; 19% of the CC group met all six criteria vs. 2% of the S group on the Objective Successful Aging Scale; 27% of the CC group vs. 13% of the S group met all six criteria on the Subjective Successful Aging Scale. Correlations among the five outcome measures ranged from r = .19 to .48 (median value: r = .26 or 7% shared variance). There is wide variability in outcome in later life depending on which measure is used. Rather than one universal indicator, each measure offers a different perspective that can provide useful guidelines for researchers, clinicians, and policy makers. [ABSTRACT FROM AUTHOR]

Abstract: The nucleophilic reaction of NaCN with the acetyl derivative of Baylis–Hillman adducts in the presence of a phase-transfer catalyst in aqueous medium stereoselectively affords the corresponding allyl cyanides in a short period and excellent yields. [Copyright &y& Elsevier]

Abstract: A convenient synthesis of new 5,6,7,8-tetrahydro-imidazo[1,2-a]pyrimidin-2-ones and 3,4,6,7,8,9-hexahydro-pyrimido[1,2-a]pyrimidin-2-ones from the Baylis–Hillman adducts of acrylonitrile and their derivatives is described. A common strategy employed to achieve the syntheses of title compounds involved generation of diamines from different Baylis–Hillman derivatives followed by treatment with cyanogen bromide at reflux temperature to trigger a double intramolecular cyclization. [Copyright &y& Elsevier]

Abstract: Trifluoroacetic acid has been discovered to be a highly effective and efficient reagent for the tandem Claisen rearrangement and cyclization reaction to yield 3-arylmethylene-3,4-dihydro-1H-quinolin-2-ones from compounds obtained from the SN2 reaction between anilines and acetyl derivatives of Baylis–Hillman adducts of acrylates in the presence of DABCO. In contrast, similar compounds obtained from the acetyl derivatives of Baylis–Hillman adduct of acrylonitrile on treatment with trifluoroacetic acid directly furnish 3-arylmethyl-2-amino-quinoline via tandem Claisen rearrangement, cyclization and isomerization. [Copyright &y& Elsevier]

Abstract: The synthesis of several 1-(2-cyano-3-aryl-allyl)-3-aryl-urea(thiourea) constructed from the reaction between allylamines generated from Baylis–Hillman acetates and substituted isocyanates and isothiocyanates has been described. Further, their cyclization in the presence of a base led to the formation of 5-arylmethyl-4-imino-3-aryl-3,4-dihydro-1H-pyrimidin-2-ones. All compounds were tested for their antibacterial activity. Few of the compounds showed superior activity or were equipotent to the standard antibacterial agents. [Copyright &y& Elsevier]

High throughput in vivo laboratory models is need for screening and identification of effective therapeutic agents to overcome microbial drug-resistance. This study was undertaken to evaluate in vivo antimicrobial efficacy of short-chain antimicrobial peptide- Cecropin A (1–7)-Melittin (CAMA) against three multi-drug resistant enteroaggregative Escherichia coli (MDR-EAEC) field isolates in a Galleria mellonella larval model. The minimum inhibitory concentration (MIC; 2.0 mg/L) and minimum bactericidal concentration (MBC; 4.0 mg/L) of CAMA were determined by microdilution assay. CAMA was found to be stable at high temperatures, physiological concentration of cationic salts and proteases; safe with sheep erythrocytes, secondary cell lines and commensal lactobacilli at lower MICs; and exhibited membrane permeabilization. In vitro time-kill assay revealed concentration- and time-dependent clearance of MDR-EAEC in CAMA-treated groups at 30 min. CAMA- treated G. mellonella larvae exhibited an increased survival rate, reduced MDR-EAEC counts, immunomodulatory effect and proved non-toxic which concurred with histopathological findings. CAMA exhibited either an equal or better efficacy than the tested antibiotic control, meropenem. This study highlights the possibility of G. mellonella larvae as an excellent in vivo model for investigating the host-pathogen interaction, including the efficacy of antimicrobials against MDR-EAEC strains. [ABSTRACT FROM AUTHOR]

Flavobacterium species have emerged as a significant pathogen in aquaculture worldwide. Therefore, there is a need to investigate the occurrences of Flavobacterium species and their pathogenicity in aquaculture. In this study, gram-negative, short rod-shaped isolates of Flavobacterium tructae, positive for the flexirubin pigment test (30% KOH) and exhibiting gliding movement, were recovered from the caudal peduncle of farmed infected rainbow trout, Oncorhynchusmykiss, in the Indian Himalayan Region. The isolates were characterized by biochemical, 16S rRNA, phylogenetic analysis, and designated as laboratory strain RTFCPB 279 and submitted to NCBI (MT896143.1). Experimental infection of rainbow trout fingerlings with F.tructae RTFCPB 279 at 108 CFU mL−1 demonstrated clinical signs of disease progression, leading to nearly 50% cumulative mortality. The survival of the bacterium in blood serum, hemolytic activity, and biofilm formation were indirectly correlated with its virulence characteristics. The serum-enzyme assay showed a significant increase in aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities in the liver of infected trout. The histopathological assessment of the gill, liver, kidney, spleen, and muscle tissues of rainbow trout collected from both natural and experimental infections showed several degenerative changes. The test bacterium was found to be sensitive to macrolides, phenicols, tetracycline, aminoglycosides, and folate pathway inhibitors, indicating the potential therapeutic use of these antibiotics. The lowest MICs of 4, 16, and 32 μg mL−1 were recorded against the FDA-approved erythromycin, oxytetracycline, and florfenicol, respectively. The study concludes that F.tructae RTFCPB 279 is an opportunistic pathogen and the correlation between environmental factors and infection dynamics of F.tructae may require further investigation to evaluate its actual risk in global aquaculture. The prudent use of erythromycin and oxytetracycline can help control the infection of F.tructae in rainbow trout culture. Highlights: • Flavobacterium tructae, an opportunistic pathogen in the flavobacteria group, was isolated from farmed rainbow trout in the Indian Himalayan Region. • In the experimental infections of rainbow trout fingerlings at a concentration of 108 CFU mL-1, the bacterium demonstrated moderate pathogenicity. Additionally, the bacterium exhibited in vitro biofilm formation and haemolytic activity. • Antimicrobial susceptibility assays demonstrated F. tructae's sensitivity to various antibiotic classes, including macrolides, phenicols, tetracycline, aminoglycosides, and folate pathway inhibitors. • Among the approved antibiotics for aquaculture, erythromycin, florfenicol, and oxytetracycline recorded the lowest minimum inhibitory concentrations (MICs) against the bacterium [ABSTRACT FROM AUTHOR]

Background: Aeromonas hydrophila is considered as a major bacterial pathogen to fish. It's wide host susceptibility has caused huge economic losses in aquaculture. In the present study, the lethal dose (LD50 96 h) of Aeromonas hydrophila, RTMCX1 and its control through oxytetracycline hydrochloride was appraised in fry of golden mahseer, Tor putitora. Methods: LD50 96 h of A. hydrophila, RTMCX1 in fry of golden mahseer was calculated through Probit model analysis. The total microbial load in muscle tissue of infected fry was estimated using standard microbial technique. The effect of oxytetracycline hydrochloride treatment was assessed at varied concentrations; 20, 40, 60 and 80 mg L-1 in experimentally infected fry at 108 CFU mL-1 of A. hydrophila. Result: LD50 96 h of A. hydrophila, RTMCX1 in fry of golden mahseer was calculated as 108 CFU mL-1. The total microbial load in muscle tissue of infected fry was ranged from 103-107 CFU mL-1. The post infection by the test bacterium demonstrated 25% of cumulative mortality in golden mahseer fry. The abnormal behaviour of the experimental fry was become normal and feed intake increased (scale 3) within 96 h of successive oxytetracycline hydrochloride bath treatment 1 h every day at 20 to 80 mg L-1. Post 96 h oxytetracycline hydrochloride treatment at 40-80 mg L-1 also demonstrated significant survival percentage (75-80%) in fry as compared to the group treated with 20 mg L-1 and positive control (p<0.05). The present study determined the LD50 of A. hydrophila at 108 CFU mL-1 in golden mahseer fry and its effective control through administration of oxytetracycline hydrochloride bath treatment 1 h at 40 mg L-1 for 4 consecutive days. [ABSTRACT FROM AUTHOR]

The present study evaluated intracellular antibacterial efficacy of two short-chain cationic antimicrobial peptides (AMPs) namely, Cecropin A (1–7)-Melittin and lactoferricin (17–30) against three field strains of multi-drug resistant Salmonella Enteritidis. Initially, antimicrobial ability of both the AMPs was evaluated for their minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against multi-drug resistant S. Enteritidis strains. Besides, the AMPs were evaluated for its in vitro stability (high-end temperatures, proteases, physiological concentrations of cationic salts and pH) and safety (haemolytic assay in sheep erythrocytes; cytotoxicity assay in murine macrophage RAW 264.7 cell line and human epithelioma HEp-2 cell line and beneficial gut lactobacilli). Later, a time-kill assay was performed to assess the intracellular antibacterial activity of Cecropin A (1–7)-Melittin and lactoferricin (17–30) against multi-drug resistant S. Enteritidis in RAW 264.7 and HEp-2 cells. The observed MBC values of Cecropin A (1–7)-Melittin and lactoferricin (17–30) against multi-drug resistant S. Enteritidis (128 μM; 256 μM) were generally twice or four-fold greater than the MIC values (64 μM). Further, both the AMPs were found variably stable after exposure at high-end temperatures (70 °C and 90 °C), protease treatment (trypsin, proteinase K, lysozyme), higher concentration of physiological salts (150 mM NaCl and 2 mM MgCl 2) and hydrogen ion concentrations (pH 4.0 to 8.0). Both the AMPs were found non-haemolytic on sheep erythrocytes, revealed minimal cytotoxicity in RAW 264.7 and HEp-2 cells, and was tested safe against beneficial gut lactobacilli (L. acidophilus and L. rhamnosus). Intracellular bacteriostatic effect with both cationic AMPs against multi-drug resistant S. Enteritidis was evident in RAW 264.7 cells; however, in both the cell lines, the significant bactericidal effect was not observed (P > 0.05) with both cationic AMPs understudy against multi-drug resistant S. Enteritidis. Based on the results of the present study, both the cationic AMPs understudy may not be useful for the intracellular elimination of multi-drug resistant S. Enteritidis; hence, further studies such as conjugation of these AMPs with either cell-penetrating peptides (CPP) and/or nanoparticles (NPs) are warranted. • Intracellular efficacy of two AMPs was explored against MDR- Salmonella Enteritidis. • In vitro, both AMPs, CAMA and lactoferricin (17-30) were found stable and safe. • Significant intracellular clearance of MDR- S. Enteritidis was not evident with both AMPs. • Conjugation studies with either CPP and/or nanoparticles are warranted for both AMPs. [ABSTRACT FROM AUTHOR]

A novel Com1 synthetic peptide-based latex agglutination test (LAT) was developed and evaluated against commercial ELISA kit for sero-screening of coxiellosis in cattle. The developed test is economical, has field applicability and can serve as an important rapid tool for sero-screening of coxiellosis in cattle. [ABSTRACT FROM AUTHOR]

Flavobacterium columnare, the causative agent in columnaris disease, leads to the mass mortality in many cultured freshwater fish species globally. Flavobacterium columnare (n = 7) was isolated from the gill lesions of farmed rainbow trout, Oncorhynchus mykiss in Central Indian Himalayan region. The bacterium was identified by colony characteristics, partial amplification of 16S rRNA gene and phylogenetic analysis. The partially amplified 16S rRNA gene (~1400 bp) was sequenced and matched with (>99%) the sequences of other F. columnare strains in the GeneBank and designated as F. columnare , BRTAGILLFC 01. From phylogenetic analysis of 16S rRNA sequences of F. columnare, the isolate was assigned to genetic group 2. The in-vitro assays for the virulence characteristics of the F. columnare BRTAGILLFC 01 revealed its ability for hemolysis, biofilm formation, protease production and capsule formation. In transmission electron microscopy (TEM), the negatively stained bacterial samples revealed the presence of capsular structure and large numbers of fimbriae. The experimental infection of rainbow trout fingerling with F. columnare BRTAGILLFC 01 at 1.5 × 108 CFU mL−1 reproduced the disease and led to cumulative mortality of 60% within 30 days. The post challenge observations illustrated swelling and hemorrhage in gill, abnormal behavior and pigmentation, decreased feeding and increased mortality in infected rainbow trout fingerlings. The histopathology of trout depicted severe degenerative changes in gill such as necrosis, fusion of secondary gill lamellae, hypertrophy, hyperplasia and epithelial lifting. The other organs revealed cellular hypertrophy, congestion and vacuolation in liver, renal corpuscle dilation and tubular necrosis in kidney and melanomachrophage aggregation in spleen. Among all therapeutic antibiotics, the bacterium was susceptible to oxytetracycline, erythromycin, ampicillin and florfenicol at the lower concentrations. In conclusion, the study confirms the first report of F. columnare infection in gill tissue of farmed rainbow trout in Central Himalayan region of India. • Flavobacterium columnare , the causative agent of columnaris disease, was isolated from trout farms in Central Himalayan region of India. • The bacterium exhibited virulence characteristic for hemolysis, biofilm formation and protease production. • Capsular structure and fimbriae as sign of pathogenicity was observed through negatively stained transmission electron microscopy (TEM). [ABSTRACT FROM AUTHOR]