African Journal of Infectious Diseases Research

African Journal of Infectious Diseases Research ISSN 4729-6836 Vol. 4 (11), pp. 001-009, November, 2017. © International Scholars Journals

Full Length Research Paper

Comparison of pathogen enrichment methods for detecting Acidovorax avenae subsp. citrulli” from watermelon seeds

WANG Jing¹, LIU Qing², CHEN Nian-lai³, LIU Jin-zhi⁴, and BI Yang¹*

¹College of Food Science and Engineering, Gansu Agricultural University, Lanzhou 730070, P.R. China

²Gansu Entry-Exit Inspection and Quarantine Bureau, Lanzhou, 730020, P.R. China.

³College of Resources and Environment, Gansu Agricultural University, Lanzhou 730070, P.R. China.

⁴College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, P.R. China.

Accepted 18 May, 2017

Abstract

It is well known that bacterial fruit blotch (BFB) of watermelon caused by Acidovorax avenae subsp. citrulli threatens watermelon production. There is no pathogen enrichment or concentrated steps before detection in conventional PCR-based diagnostic technique, which consequently leads to the lower detection sensitivity. In the present study, two different bacterial suspensions were prepared, and four pathogen enrichment protocols including Biological Preparation (BP), Membrane Filtration (MF), Immune-Magnetic Separation (IMS) and Immune-Capture Preparation (ICP) were employed to prepare the PCR template for the pathogen detection. Double Antibody Sandwich Enzyme Linked Immunosorbent Assay (DAS-ELISA) was also conducted as a parallel comparison. The results showed that IC-PCR was the optimum method through comparing the detection limits, time and expenditure among those methods. The detection limit of IC-PCR for both bacterial suspension and seeds suspension can reach 10² CFU/ml, which was 10 times lower than that of IMS-PCR when the seed suspension was used as template. In addition, the results of IC-PCR showed higher degree of precision than those of IMS-PCR. The time and expenditure of IC-PCR were comparable with other methods. The present study demonstrated that the procedures of immune-capture PCR is a sensitive, specific, rapid, reproducible, and economical method to detect A. avenae subsp. citrulli in watermelon seeds.

Key words: Bacterial Fruit Blotch, watermelon seed, pathogen enrichment, PCR.

African Journal of Infectious Diseases Research ISSN 4729-6836 Vol. 4 (10), pp. 001-006, October, 2017. © International Scholars Journals

Full Length Research Paper

Interplay between calcium influx and nitrate assimilation in Spirulina platensis

Pradeep Kumar Logeswaran, Vinky Kohli and B Vani*

Centre for Biotechnology, Department of Biological Sciences, Birla Institute of Technology and Science, Pilani - 333031, Rajasthan, India.

Accepted 22 July, 2017

Abstract

Nitrate assimilation and its interplay with Ca²⁺ ion transport has been studied in Spirulina platensis PCC 7345, an alkaliphilic filamentous cyanobacterium. We have used verapamil, a calcium-channel blocker and sodium orthovanadate, a calcium efflux blocker, to study the effect of nitrate assimilatory setup. Nitrate uptake (NU) increased significantly with verapamil but was inhibited by sodium orthovanadate. Nitrate reductase and nitrite reductase activities were stimulated with verapamil as well as sodium orthovanadate. Glutamine synthetase activity was not significantly altered by both the inhibitors. Our results suggest that the steady state levels of NU, NR and NiR activities are inter linked with Ca²⁺ influx into the cells from the external medium.

Key words: Spirulina, nitrate uptake (NU), nitrate reductase (NR), nitrite reductase, glutamine synthetase.

Key words: Iran, Norwalk virus, RT-PCR, marine foods.

African Journal of Infectious Diseases Research ISSN 4729-6836 Vol. 4 (8), pp. 001-007, August, 2017. © International Scholars Journals

Full Length Research Paper

Ultra-structure of the yeast Trichosporn mycotoxinivorans and its effect on some biological parameters in mice

Abdulla S. Khaliel^1*, Jamal M. Khaled¹ and Saleh A. Kandeal^1,2

¹Department of Botany and Microbiology, Collage of Science, King Saud University, Riyadh, Saudi Arabia.

²Department of Zoology, Collage of Science, King Saud University, Riyadh, Saudi Arabia.

Accepted 16 March, 2017

Abstract

In this research work, the ultra-structure of yeast, Trichosporon mycotoxinivorans was studied by scanning and transmission electron microscopy. Effects of yeast on biological parameters in mice including body weight, mortality rate and compounds in blood (glucose, total protein, cholesterol, and insulin) were estimated. Blood constituents (White blood cells (WBC), Red blood cells (RBC) haemoglobin (HGB), hematorit (HCT) and platelets (PLT), mean cell volume (MCV), mean corpuscular haemoglbin (MCH) and mean corpuscular haemoglobin concentration (MCHC) were determined. The results indicated that the ultra-structure of the organism is found to be similar to most of the basidomycetes yeasts. T. mycotoxinivorans yeast increases weight of mice and reduces the rate of mortality. It did not have any negative effect on the compounds and blood constituents in mice. These results suggest that this yeast could be used as a probiotic in animal feeding to reduce the risks of mycotoxins.

Key words: Ultra-structure, mycotoxinivorans, mycotoxinis, trichosporon, blood constituents.

African Journal of Infectious Diseases Research ISSN 4729-6836 Vol. 4 (7), pp. 001-008, July, 2017. © International Scholars Journals

Full Length Research Paper

Evaluation of the dry sheet medium (Compact Dry LS) for screening of total Listeria count in food samples

Hajime Teramura*, Masafumi Uchida, Mitsuaki Kashida and Hidemasa Kodaka

Nissui Pharmaceutical Co., Ltd.1075-2 Hokunanmoro, Yuki, Ibaraki, 307-0036, Japan.

Accepted 26 October, 2016

Abstract

The Compact Dry LS (CD-LS), ready-to-use dry sheet selective medium for Listeria species, was evaluated for inclusivity and exclusivity by using 107 strains including 20 Listeria species strains. All tested Listeria species strains other than Listeria seeligeri that grew as blue colored colony on CD-LS. CD-LS were compared with those on Oxford agar and ALOA agar as conventional methods using Listeria species inoculated from 100 food samples. The correlation coefficients between CD-LS and Oxford agar, and CD-LS and ALOA agar were 0.983 and 0.978, respectively. Our results suggested CD-LS was a suitable alternative medium for screening of Listeria species.

Key words: Chromogenic selective medium, ready-to-use medium, Listeria, compact dry.

African Journal of Infectious Diseases Research ISSN 4729-6836 Vol. 4 (6), pp. 001-004, June, 2017. © International Scholars Journals

Full Length Research Paper

Bacterial contamination of healthcare workers' mobile phones and efficacy of surface decolonization techniques

Maryam Mohammadi-Sichani* and Vajiheh Karbasizadeh

Department of Microbiology, Falavarjan Branch-Islamic Azad University - Esfahan- Iran.

Accepted 27 October, 2016

Abstract

This study was performed to determine the rate of bacterial contamination of mobile phones of healthcare workers and the efficacy of 70% Ethyl alcohol and 70% Isopropyl alcohol as disinfectant agents. 150 mobile phones of healthcare workers in Esfahan's hospital were included. Samples were collected by sterile, moistened swabs and were cultured on blood agar and EMB and then isolates were identified. In separate studies, we assessed the effectiveness of Ethyl and Isopropyl alcohol against mobile phone surface contamination with Staphylococcus aureus (ATCC: 25923), E.coli (ATCC: 25922), Pseudomonas aeroginosa (ATCC: 27853) and Enterococcus faecalis (ATCC: 9854).In total, 94% of mobile phones demonstrated evidence of bacterial contamination including Coagulase-negative Staphylococcus, Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Pseudomonas aeroginosa and non-fermentative Gram negative bacilli. Both Ethyl and Isopropyl alcohol were effective at decontaminating mobile phones of test bacteria. Healthcare workers' mobile phones were contaminated in the hospital environment and therefore may potentially serve as vehicles of transmission of pathogenic bacteria. Strict adherence to infection control, such as hand washing and mobile decontamination is advocated. Ethyl and Isopropyl alcohol were highly effective at removing or inactivating pathogenic bacteria on surface of mobile phones.

Key words: Bacterial contamination, healthcare workers, mobile phone, nosocomial infection.