Open Access Short communication

Effects of PH and Storage Temperatures on Antibacterial Activity of Bacteriocin Produced by Lactic Acid Bacteria Isolated from OGI

R. E. Ohenhen, J. O. Isibor, G. Emonfonmwan, S. A. Enabulele

Microbiology Research Journal International, Page 1-9
DOI: 10.9734/BMRJ/2015/13471

Aims: Lactic acid bacteria are important organisms recognized for their fermentative ability. They produce various compounds including bacteriocins which are proteinaceous antimicrobial compounds. The purpose of this study was to evaluate the lactic acid bacterial content of ogi, extract crude bacteriocin from the lactic acid bacterial isolate(s) and determine the effects of pH and storage temperature on the antimicrobial properties of the crude bacteriocin extract.

Study Design: The study was designed to isolate and characterise lactic acid bacteria from ogi, thereafter extract crude bacteriocins from the isolates and then determine the antibacterial activities of the bacteriocins so extracted against some known indicator organisms.

Place and Duration of Study: Ogi samples were purchased from vendors who hawk it around the Benson Idahosa University campus and the study was done at the Department of Basic Sciences, Faculty of Basic and Applied Sciences, Benson Idahosa University, Benin City, Nigeria; between October 2012 and June 2013.

Methodology: Preliminary isolation and characterization of lactic acid bacteria was done using standard microbiological methods after which the bacteriocins were extracted by propagating in 500ml MRS broth (pH 7.0 glucose 0.25% w/v) and incubated for 72 h at 30ºC under anaerobic conditions. Extract was obtain by centrifuging cultures at 10,000 rpm for 20 min. Antimicrobial activity of the extract was determined using agar well diffusion method. Indicator organisms utilized were; Escherichia coli and Staphylococcus aureus. The effects of pH and storage temperatures of the crude bacteriocin, on the antimicrobial properties were determined using standard methods.

Results: Lactobacillus plantarumLactobacillus caseiLactobacillus brevisLactobacillus fermentum and Lactobacillus jensenii were the lactic acid bacteria species isolated and identified from the Ogi samples. Lactobacillus plantarum had the highest zone of inhibition during the screening test for antibacterial activity and was used to produce the bacteriocins used for the subsequent tests. At pH 2, there was a high antimicrobial activity but at pH 10, there was no antimicrobial activity. Crude bacteriocin extract stored at -20ºC also showed the highest antimicrobial activity.

Conclusion: This study has established that Ogi is a viable source of several lactobacilli which are capable of producing several antimicrobial compounds such as bacteriocins. It also established that bacteriocins recovered from Lactobacillus plantarum have a potent antimicrobial activity against a variety of both diarrhoeagenic and spoilage bacterial.

Open Access Short communication

Microbiological Safety Assessment of Selected Smoked Fish in Lagos Metropolis

O. N. Olaleye, T. A. Abegunde

Microbiology Research Journal International, Page 1-5
DOI: 10.9734/BMRJ/2015/17161

This research assessed the microbiological quality of smoked fish consumed around the Lagos metropolis to ascertain the safety for consumption. Four samples of selected smoked fish obtained from five market locations in Lagos, Nigeria were analyzed to determine their bacteria loads. The selected smoked fish samples examined were Herring- Clupea harengus (“Sawa”), Horse Mackerel - Trachurus trachurus (“Kote”), Great Barracuda - Sphyraena barracuda (“Panla”) and Atlantic Mackerel- Scomber scombrus (“Titus”). The examined fish samples that were obtained were contaminated with some bacteria species. The average total aerobic bacterial counts from all the samples ranged from 4.2 x 106 cfu/g to 7.5 x 106 cfu/g. Scomber scombrus (Titus), Clupea harengus (Sawa) had higher average total aerobic bacteria counts of 7.5 x 10cfu/g and 6.0 x 106 cfu/g respectively. The average coliform counts obtained from the smoked fish were, 2.2 x 106cfu/g, Trachurus trachurus (Kote); 4.8 x 106 cfu/g, Clupea harengus; 5.1 x 106 cfu/g, Scomber scombrus and 3.7 x 106 cfu/g for Sphyraena barracuda. Adequate cooking is recommended for consumers of smoked fish to prevent food borne illnesses.

Open Access Original Research Article

The Characterization of Bacterial Cellulose Produced by Acetobacter xylinum and Komgataeibacter saccharovorans under Optimized Fermentation Conditions

Enas A. Hassan, Hemmat M. Abdelhady, Sohir S. Abd El-Salam, Sara M. Abdullah

Microbiology Research Journal International, Page 1-13
DOI: 10.9734/BMRJ/2015/18223

Aims: studying the biological activities of A. xylinum ATCC 10245 (as reference strain) and K. saccharivoransPE5 for bacterial cellulose production (B.C) under optimized fermentation conditions and the structural characteristics of cellulose produced.
Study Design: The production of bacterial cellulose under optimal fermentation conditions by investigated strains then the purified cellulose was characterized by different techniques.
Place and Duration of Study: Agric. Microbiology Dept., Fac. of Agriculture, Ain Shams Univ., Cairo, Egypt.
Methodology: A. xylinum ATCC 10245 and K. saccharivorans PE5 strain were used as producers of bacterial cellulose. These strain were grown on productive medium under optimal fermentation conditions. The parameters of growth and B.C production were determined during the fermentation period. The specific growth rate, doubling time. Multiplication rate and generation number were calculated during the exponential phase of growth. Purified polymers were characterized and the properties of paper sheet were detected.
Results: Results indicated that the exponential phase of Komagataeibacter saccharivorans PE 5 and Acetobacter xylinum ATCC 10245 growth was detected during the first 48 to 144 hrs and during 168 hrs in productive media, respectively. The highest cellulose concentration and yield were obtained after 336 hrs by both tested strains being 11.11 gl-1 & 74.1% for Acetobacter xylinum ATCC 10245 and being 12.61 gl-1 & 84.11% for Komgataeibacter saccharivorans PE 5. The structure of BC produced from the tested strains was assayed by scanning electron microscope, fourier transform- infrared spectrum (FT-IR) and x-ray diffraction. It was revealed the diameter of thin ribbons ranged from 34.34 nm to 39.16 nm and the shape of FT-IR spectra for the two stains is similar to pure cellulose. The crystalinity index of A. xylinum ATCC 10245 is 54.14% and 52.76% for K. saccharivorans PE 5. Also, the properties of paper sheet from K. saccharivoransPE 5 cellulose increased about 1.19, 1.25, 1.33, 1.91 and 1.27 fold for wet tensile strength, dry tensile strength, degree of polymerization, brightness and opacity, respectively than A. xylinum ATCC 10245 cellulose.

Open Access Original Research Article

Microbiological Assessment of Stool Specimens of Children with Diarrhoea in Benin City, Nigeria

P. E. Imade, N. O. Eghafona

Microbiology Research Journal International, Page 1-8
DOI: 10.9734/BMRJ/2015/18510

Diarrhoeal disease is a public health problem for children worldwide especially in developing countries. This study aimed at assessing the microbial agents associated with childhood diarrhoea in Benin City, Nigeria. Faecal specimens were collected from patients and controls within 0-60 months of age and were analyzed by microbiological techniques. Viral agents were detected by immunochromatographic method, parasitic agents by microscopic method, while bacteria and fungi were isolated by cultural method. The overall results showed a prevalence of 208 (41.3%) for patients and 7 (5.7%) for control. Sex and age group did not show statistical significance (P>0.05) with respect to diarrhoea. However, maternal occupation and season of the year showed statistical significance with P=0.001 and P=0.029, respectively. Antibiotic susceptibility pattern showed that the bacterial isolates were most sensitive to Ceftriazone, Ofloxacin, Ceftazidine and Cefuroxime. Microbial associated diarrhoea is still a public health problem in Benin City, Nigeria, as seen in the 41.3% prevalence. Bacteria, viruses, fungi and parasites were found to be associated with the infection. Thus, comprehensive stool analysis is needed for determining the pathogen in patients with clinical symptoms of diarrhoea in this locality.

Open Access Original Research Article

Vancomycin Resistant Enterococci Infections in Trinidad and Tobago

Shivnarine Kissoon, Patrick Eberechi Akpaka, William Henry Swanston

Microbiology Research Journal International, Page 1-8
DOI: 10.9734/BMRJ/2015/18531

Aims: To document Vancomycin Resistant Enterococci (VRE) infections prevalence, risk factors, antimicrobial susceptibility patterns and evaluation of chromogenic plates in identifying VRE isolates in Trinidad and Tobago.
Study Design: This was a cross sectional prospective observational and descriptive study.
Place and Duration of Study: Study was carried out in all major regional hospitals in Trinidad & Tobago over a four year period, 2009 to 2013.
Methodology: All cases of Enterococcus infections from major hospitals in the country were reviewed. Standardized questionnaire was used to analyze epidemiological and clinical data of VRE infected patients. Enterococcal speciation, minimum inhibitory concentrations (MIC) were evaluated using Microscan Walk Away 96SI (Siemens, USA). Isolates were further identified using 6.5% NaCl and pyrrolidonyl arylamidase activity according to CLSI guidelines. Brain Heart Infusion agar, Bile esculin azide agar containing 6 mg/L of vancomycin and chromogenic agar plates - Chromagar VRE and chrom ID VRE were used to screen and confirm VRE isolates
Results: A low (3.9%) VRE infections were encountered from 1,141 enterococcal infections reviewed. Majority of these infections occurred in the surgical facilities (42%) and least from the burns unit (2%) respectively. No significant association was observed between VRE infections and patients’ gender, age, wards or hospital facilities. However underlying diseases such as diabetes mellitus and hypertension; and prior use of antibiotics on or before admission were noted to be associated with the VRE infections.
All the VRE infections were mainly caused by E. faecium and E. faecalis that were completely (100%) resistant to ciprofloxacin, erythromycin, levofloxacin, rifampin and vancomycin, but were 95% and 100% susceptible to gentamycin and linezolid respectively. Overall, performance of the chromogenic agar plates were 100% sensitive and specific for VRE
Conclusion: In Trinidad & Tobago VRE infections prevalence although low are strongly associated with high antibiotic consumption, prolonged hospitalization and diabetes mellitus disease. Linezolid is highly susceptible to multidrug resistant VRE isolates in the country. Chromogenic VRE media produced rapid and reliable identification of VRE organism. Further use of molecular studies to monitor the epidemiology of VRE infections in hospitals in the country is highly recommended.

Open Access Original Research Article

Molecular and Serological Studies for Detection and Identification of Cotton Leaf Curl Virus in Cotton Plant (G. barbadense L.) in Egypt

Azza Makhlouf, D. G. Asse, E. E. Hafez, M. A. EL Seehy

Microbiology Research Journal International, Page 1-9
DOI: 10.9734/BMRJ/2015/18939

Aims: Cotton production contributes in economic security in Egypt.  Cotton leaf curl virus (CLCuV) belongs to the Begomovirus genus and Geminiviridae family that is transmitted by the whitefly Bemisia tabaci. It is the greatest current threat where cotton is grown. In Egypt, a distinct Begomovirus causing leaf curl has been identified in okra, tomato, hollyhock and other malvaceous species suggesting that it could possibly infect Egyptian cotton. The aim of this study was the detection and isolation of this Virus from Egyptian cotton fields.

Methodology: Diseased leaves of cotton, okra and tomato plants were collected from different localities during 2009; samples were subjected to DAS-ELISA for viral detection. Coat protein (CP) gene of the virus was amplified by PCR, sequenced and aligned with the others Begomovirus available in the GenBank. Cloning and sub cloning of CP gene for cotton virus were performed and its recombinant protein was separated on SDS-PAGE. DBIA was also used to identify protein of the virus.

Results: The amplified fragment of the CP gene was about 280bp in all samples. The CP gene of CLCUV in our study shared 97% identity with CLCuV isolate from Pakistan while, CP gene amplicon of okra leaf curl virus (OLCUV) showed identity of 84% with three isolates of tomato leaf curl virus (TYLCV) from Chian. The recombinant protein of CLCUV was about 24kDa and positive relatedness was shown between this recombinant protein and TYLCuV antiserum.

Conclusion: our study showed the existence of such virus in malvaceous species as okra plant may be causes a serious problem for cotton production in Egypt. Also, the CP gene is a good tool for examination the existence of the virus in the infected fields. The purified protein of CLCUV can use as an antigen to produce its antibodies.