Bioactivity of Alcaligenes faecalis and Lecanicillium sp. isolated from crocker range of Sabah against Erwinia psidii of papaya dieback disease

Aims@#Erwinia psidii was first reported in 2017 to be the causal pathogen of papaya dieback disease (PDD) in Sabah, Malaysia. The present study aimed to isolate potential biocontrol agents against this pathogen. @*Methodology and results@#Out of the 20 samples collected from Crocker Range of Sabah, 154 bacteria and 55 fungi isolates were isolated and screened for their antagonistic activity against E. psidii. The fungi and bacteria which gave the highest inhibition to E. psidii were identified using molecular technique as Alcaligenes faecalis and Lecanicillium sp., respectively. Both isolates were selected for extraction of their secondary metabolites to determine their bioactivity against E. psidii. Micro-well dilution method was used to determine minimum inhibitory concentration (MIC) for each microbes’ extract. GC-MS analysis was carried out to determine their secondary metabolites. @*Conclusion, significance and impact of study@#Lecanicillium sp. (Diethyl ether, chloroform and ethyl acetate) extracts and A. faecalis (Diethyl ether extract) showed positive inhibition against E. psidii. GC-MS analysis revealed that both A. faecalis and Lecanicillium sp. had secreted some secondary metabolites such as N-formylmaleamic acid, Oleamide and D-1-Piperideine-2-carboxylic acid that may relate to the growth inhibition. Alcaligenes faecalis and Lecanicillium sp. are potential to be further investigated as biocontrol against E. psidii.

Characterization of Cd(II)/Pb(II) transcriptional regulator Alcaligenes faecalis SF-S1-60

Aims@#Metal transcriptional regulators controlled the regulation of metal ion homeostasis in bacteria genera. Cd(II)/Pb(II) transcriptional regulator is one of the member of MerR family found in Alcaligenes faecalis SF-S1-60 (PbrT-AF). @*Methodology and results@#The PbrT-AF gene with 432 bp open reading frame was successfully isolated from genomic DNA of A. faecalis using polymerase chain reaction (PCR) analysis. This gene was phylogenetically grouped with A. alcaligenes species using PHYLIP version 3.69 by the neighbor-joining method with 1000 bootstrap replicates. Phylogeny analysis shows that these proteins have distinct amino acids compared to Cd(II)/Pb(II) regulators from different species. The structure of PbrT-AF shows similar conformation with other members of MerR family using MODELLERv9.17. We also demonstrated that the expression of Pbrt-AF in Escherichia coli BL21 were able to increase the bacteria tolerance towards Pb up to 1000 ppm. @*Conclusion, significance and impact of study@#This result suggests that PbrT-AF promotes cell adaptation and tolerance towards Pb toxicity.

Isolamento de Alcaligenes faecalis em peixe Betta splendens Regan, 1910 no Brasil / Isolation of Alcaligenes faecalis in fish Betta splendens Regan, 1910 in Brazil

Descreve-se um caso de infecção por Alcaligenes faecalis em peixe ornamental Betta splendens, incluindo avaliação clínica, patológica e bacteriológica. Um peixe fêmea, com peso de 16 g, inicialmente demonstrou discreta lesão escoriativa no tegumento, inapetência, emagrecimento progressivo, letargia, dispneia e aumento de volume na região lateral esquerda. Constataram-se em necropsia a presença de exoftalmia bilateral, opacidade de córnea, ascite e abscesso no subcutâneo provocando distensão da cavidade celomática. As alterações histológicas da pele se caracterizaram por abscesso, necrose, hemorragia e infiltrado inflamatório constituído principalmente de heterófilos. No exame microbiológico com exsudato e sangue venoso isolou-se exclusivamente A. faecalis.(AU)

This paper aimed to describe one case of infection by Alcaligenes faecalis in an ornamental fish Betta splendens, including clinical, pathological, and bacteriological evaluation. A female fish weighing 16 g initially showed discrete ulcerative lesions in the integument, inappetence, progressive weight loss, lethargy, dyspnea, and increased volume in the left lateral region. Necropsy revealed bilateral exophthalmia, corneal opacity, ascites, and subcutaneous abscess causing distension of the celomatic cavity. Histological changes of the skin were characterized by abscess, necrosis, hemorrhage, and inflammatory infiltrate consisting mainly of heterophils. Microbiological assays using the exudates and venous blood isolated exclusively A. faecalis.(AU)

Partial Purification and Antimycobacterial Screening of the Ethyl Acetate Extract of Alcaligenes faecalis BW1.

Aims: The focus of this study was to evaluate the antimycobacterial activity of Alcaligenes faecalis BW1 extract and to purify it partially. Study design: Partial purification of A. faecalis BW1 extract was performed by using thin layer chromatography and active substances responsible for the biological activity were localized. Place and Duration of Study: The study was carried out at laboratory of Microbial Biotechnology, Department of Biology, Faculty of Sciences and Technical, University Sidi Mohamed Ben Abdellah, BP 2202, Road of Immouzer, Fez, Morocco, during the period from January 2011 to July 2011. Methodology: Crude extract of A. faecalis BW1 was obtained by using ethyl acetate as an organic solvent and its antimycobacterial effect was investigated by agar discs diffusion method. The extract was then fractionated by thin layer chromatography and the bioactivity was assessed with a bioautography technique followed by spots elution tests. Results: The results showed that A. faecalis BW1 produced compounds with antimycobacterial activity. All the detected spots by thin layer chromatography inhibited the growth of M. smegamtis. Conclusion: Various metabolites of A. faecalis BW1 are responsible for the sought effect or they could act synergistically to inhibit mycobacterial growth. These compounds could be used after their total purification in further work against mycobacterial infections.

Tolerance Tests of Alcaligenes faecalis BW1 Extract.

Aims: To highlight whether metabolites of Alcaligenes faecalis BW1 extract can be administered orally for their possible antimycobacterial effects. Study Design: Study of the influence of certain parameters on the extract of Alcaligenes faecalis by using either discs or well diffusion methods against M. smegmatis. Place and duration of study: Laboratory of Microbial Biotechnology, Department of Biology, Faculty of Sciences and Technical, University Sidi Mohamed Ben Abdellah, BP 2202, Road of Immouzer, Fez, Morocco. From April to August, 2012. Methodology: The impact of acidic pH of gastric juice, bile, hydrogen peroxide, pancreatic enzymes and lysozyme on the antimycobacterial activity of Alcaligenes faecalis BW1 extract was evaluated by agar diffusion method. Detection whether or not antibacterial metabolites having a synergistic effect with rifampicin against M. smegmatis was also explored. Results: Antibacterial metabolites of Alcaligenes faecalis BW1 extract resist to the action of gastric pH, gallbladder bile and hydrogen peroxide. In addition, they are not affected by pancreatic enzymes and lysozyme. Moreover, they have a synergistic effect with rifampicin against M. smegmatis. Conclusion: Anti-mycobacterial metabolites of Alcaligenes faecalis BW1 extract are compatible with rifampicin and could be administered orally as antitubercular agents after their purification, identification in further work.

A Case of Corneal Ulcer by Alcaligenes Faecalis

PURPOSE: To report a case of corneal ulcer due to Alcaligenes faecalis in a patient with a preexisting corneal ulcer. CASE SUMMARY: A 58-year-old male patient presented with a corneal ulcer without a history of any trauma. The patient had a history of corneal ulcer 9 months earlier. The patient had previously been diagnosed with diabetic retinopathy and neovascular glaucoma, and his visual acuity was no light perception. Corneal scraping and culture yielded Alcaligenes faecalis susceptible to most antibiotics in the antibiotic susceptibility test. After treatment with empirical systemic antibiotics and eyedrops, his eye improved with a remaining corneal scar. CONCLUSIONS: Alcaligenes faecalis should be considered as a causal pathogen of corneal ulcer in patients with suspicious compromised ocular surface, such as previous corneal ulcer.