Open Access Original Research Article

Antimicrobial and Antioxidant Properties of Aqueous Garlic (Allium sativum) Extract against Staphylococcus aureus and Pseudomonas aeruginosa

Momoh Johnson, Oluremi Nurudeen Olaleye, Odetunde Simeon Kolawole

Microbiology Research Journal International, Page 1-11
DOI: 10.9734/BMRJ/2016/24095

Aim: To investigate the antimicrobial and antioxidant properties of aqueous garlic (Allium sativum) extract against Staphylococcus aureus and Pseudomonas aeruginosa.

Methods: Determination of Proximate Composition, DPPH radical-scavenging activities, qualitative and quantitative analysis of the aqueous garlic extract (AGE) were carried out using standard methods. The antimicrobial activity was evaluated by agar well diffusion method. MIC, MBC and other microbial analyses were also determined using standard methods.

Results: The proximate composition of the garlic indicate that they contain carbohydrate (66.8%), oil (2.6%), moisture (14.5%), total ash (1.3%) and protein (14.8%). The Phytochemical analysis of aqueous extract of Allium sativum shows the presence of secondary metabolites like tannins, terpenoids, steroids, saponins, phenol, protein and reducing sugar. The amount of total phenol content present was 0.285±0.0226 mg/ml while that of flavonoid content was 28.74±8.23 mg QUE/ml. The DPPH scavenging activity of the extract range from 4.47% to 92.44% for the garlic extract with corresponding to concentration range from 3 to 40 mg/ml while the IC50 value was 25.3 mg/ml. Agar well diffusion method was used to determine the antimicrobial activity of the garlic extract. It was characterized by inhibition zones of 25.6±2.4 mm for S. aureus and 28.1±1.8 mm for P. aeruginosa. Pseudomonas aeruginosa was tested against 10 standard antimicrobial agents, of these; chloramphenicol, ciprofloxacin, septrin, pefloxacin, streptomycin, gentamicin, amoxacillin, and sparfloxacin were sensitive while augmentin and tarivid were resistant to the tested organism. Staphylococcus aureus were susceptible to pefloxacin, amoxacillin, ciprofloxacin, streptomycin, and septrin. Resistance to gentamicin, ampiclox, zinnacef, rocephin and erythromycin were also observed with the same organism. The minimum inhibitory concentration (MIC) for P. aeruginosa was 40 mg/ml while S. aureus has a value of 80 mg/ml. The extract has a minimum bacteriocidal concentration (MBC) of 88 mg/ml for P. aeruginosa and 104 mg/ml for S. aureus. The extract has strong potency against these microorganisms with P. aeruginosa being the most susceptible.

Open Access Original Research Article

Preparation of Fowl Typhoid Vaccine from Field Isolates and Determination of Efficacy

Jannatun Nime, Mehedi Hasan, Md. Abdus Sattar, Mst. Dilara Nuri, Md. Bahanur Rahman, Afia Khatun

Microbiology Research Journal International, Page 1-7
DOI: 10.9734/BMRJ/2016/24994

The experiment was conducted to isolate and identify Salmonella gallinarum from field cases to prepare formalin killed vaccine and to determine the efficacy of experimentally prepared fowl typhoid vaccine. A total of 48 chickens were divided into six groups (group A, B, C, D, E and group of unvaccinated control chickens F) including 8 layer chickens of Sonali breed in each group. Chickens in group A, B, C, D and E were vaccinated primarily with experimentally prepared fowl typhoid vaccine with a dose 0.5 ml (4.7 × 107  CFU/ml) through subcutaneous route at the age of 9 weeks and booster dose at 14, 21, 28, 35, 42 days after primary vaccination with the same dose and route respectively. Blood samples were collected to obtain sera from each chicken after 15 days boostering for determination of antibody titre following using passive haemagglutination test. Highest mean antibody titres obtained from Group A, B, C, D and E was 96±12.04. Among the five groups the highest mean antibody titre of 96±12.04 was obtained when vaccine was given at 14, 21, 28 days after primary vaccination. The result of Challenge infection revealed that among the 8 birds of A, B, C, D and E all were protected from virulent challenge and all chickens were died from the group F. These results revealed that experimentally prepared Fowl typhoid vaccine provided 100% protection.

Open Access Original Research Article

Analysis of Volatile Compounds, Amino Acid Catabolism and Some Technological Properties of Enterococcus faecalis Strain SLT13 Isolated from Artisanal Tunisian Fermented Milk

Manel Ziadi, Sana M’hir, Robin Dubois-Dauphin, Emilie Chambellon, Mireille Yvon, Philippe Thonart, Moktar Hamdi

Microbiology Research Journal International, Page 1-12
DOI: 10.9734/BMRJ/2016/17309

Aims: Enterococcus faecalis strain SLT13, isolated from the Leben microbiota was investigated for their technological properties.

Place and Duration of Study: The study was undertaken in the LETMi laboratory, Tunis, Tunisia with collaboration with CWBI, Gembloux, Belgium, and at INRA (Unité de Biochimie Bactérienne), Jouy-en-Josas, France. The duration of the study was during the period of January 2012 to February 2013.

Methodology: Enterococcus faecalis SLT13 was identified biochemically and by ITS rDNA gene sequencing and then characterized for acidifying activity after growth in milk. Solid Phase Microextraction (SPME) and Gas Chromatography (GC) were used for analyzing the volatile profile of fermented milk obtained with SLT13. Catabolism of pheneylalanine and Leucine were studied through using radiolabelled amino acids as tracers. The rheological behavior of the fermented milk was determined using a viscosimeter.

Results: The final pH and acidity after growth of the strain SLT13 on milk were 4.29±0.1 and 75°D±2 respectively. The volatiles analyzed by SPME-GC-MS, included a wide range of volatile compounds: ketones, acids, alcohols, aldehydes, sulphur compounds and hydrocarbons.

The aminotransferase activity towards Leucine (290±95 nmol min-1 mg-1) was higher than those towards Phenylalanine and Aspartic acid (63±29 and 37±13 nmol min-1 mg-1 respectively). In fermented milk containing radiolabelled Leucine, hydroxyisocaproate was the only metabolite produced by SLT13. The main Phenylalanine degradation product was phenyllactate and small amounts of phenylethanol and phenylacetate.

The milk fermented by Enterococcus faecalis SLT13 presented a consistency coefficient K= 0.156 and the flow behaviour index n=0.09.

This strain was suited for pilot-scale production and downstream processing with an important growth rate µmax=0.9 h-1, high viable count (1.19 1010 CFU ml-1) and an important survival rate after freeze-drying (82%).

Conclusion: Enterococcus faecalis SLT13 exhibited remarkable technological properties and seems also suitable for pilot-scale production and downstream processing.

Open Access Original Research Article

Overproduction of Xylanase from Mutants of Bacillus subtilis with Barley Husk as the Prime Carbon Source under Submerged Fermentation after Random Mutagenesis Using Ethyl Methane Sulfonate (EMS) and Acridine Orange (AO)

Hooi Ling Ho, Ajounmah Maryann Chinonso

Microbiology Research Journal International, Page 1-17
DOI: 10.9734/BMRJ/2016/22959

Aims: Xylanase (EC 3.2.1.8) also known as endo-1,4-β-xylanohydrolase is a type of hydrolytic enzyme participated in the hydrolysis of hemicelluloses particularly in xylan to generate xylose and xylo-oligosaccharides. Due to its enormous potentials, xylanase is frequently used in biobleaching of kraft pulp, clarification of fruit juice, extraction of plant oils, processing of animal feeds, softening of fruits, degradation of agricultural wastes and plant fibers and manufacturing of chemicals including biofuel, ethanol and xylitol. These applications of xylanase avoid the use of chemicals that are expensive, mutagenic and highly non-biodegradable. Interestingly, in recent years, the applications of xylanase in biobleaching and bioprocessing of paper pulp have gained numerous attentions and interests in the industry over the world. Therefore, couple of lignocellulolytic substrate as the alternative cheap carbon source and strain improvement for overproduction of microbial xylanase is implemented as a more potent approach in improving its yield and productivity in submerged fermentation. As a result, the main aim of the present study was primarily involved in the overproduction of xylanase by five mutant strains of Bacillus subtilis subsp. spizizenii ATCC 6633 designated as the MXB 1, MXB 2, MXB 3, MXB 4 and MXB 5 in submerged fermentation using barley husk as the prime carbon source.

Methodology: In order to attain the mutants, B. subtilis was subjected to random mutagenesis using ethyl methane sulfonate (EMS) and acridine orange (AO) in the earlier study before screened for the overproduction of xylanase in the present investigation.

Results: Based on the present investigation, mutant strains of B. subtilis ATCC 6633 were identified as the potent xylanase producers using cheap agro-industrial residue of barley husk as the sole carbon source under submerged fermentation. Furthermore, extracellular protein production and profile of medium pH during growth of wild type and mutants of B. subtilis under submerged fermentation were also elucidated. Based on the result findings, the time course of xylanase biosynthesis by the mutants of B. subtilis revealed that the enzyme production was initiated from the logarithmic to stationary growth phase whereby the maximum xylanase activity was achieved after 24 h of fermentation. In fact, all mutant strains of B. subtilis were successfully synthesized relatively higher production of xylanase than their parental wild type in submerged fermentation using barley husk as the prime carbon source. Notably, the maximum xylanase activity of 1.76±0.02 U/mL was attained by the mutant MXB 4 of B. subtilis which was approximately 29.4% increase in xylanase activity than the wild type with 1.36±0.003 U/mL. Furthermore, MXB 1, MXB 2, MXB 3 and MXB 5 also exhibited comparatively higher maximum xylanase activity of 1.64±0.009 U/mL, 1.73±0.05 U/mL, 1.74±0.02 U/mL and 1.66±0.02 U/mL compared to their parental wild type. Indeed, the statistical single factor analysis of variance (ANOVA) on xylanase production revealed there was significant difference in the mean of the xylanase production by the wild type and mutant strains of B. subtilis (p<0.05). On the other hand, the total maximum extracellular protein production was achieved by mutant strains of MXB 2 and MXB 4 with 0.82±0.02 mg/mL and 0.82±0.03 mg/mL, respectively. Both demonstrated increment of 49.1% in protein production than the wild type which possessed relatively lower concentration of 0.55±0.01 mg/mL. Besides that, the profile of medium pH on xylanase activity by mutants and wild type of B. subtilis was also elucidated in the present study. The highest xylanase activity was attained at slight acidic pH of 6.1±0.2 as shown by the mutant MXB 4 in comparison with wild type at pH 6.47±0.3.

Conclusion: In a nutshell, the result findings suggested the mutant strains of B. subtilis ATCC 6633 particularly MXB 4 as the most potent xylanase producer under submerged fermentation using barley husk as the prime carbon source. Mutant MXB 4 of B. subtilis is anticipated to be beneficial in various xylanase applications especially in the processing of animal feeds and food industry.

Open Access Original Research Article

Prevalence of Methicillin-resistant Staphylococcus aureus among Health Care Workers in Tripoli Hospital, Libya

Basma Doro, Wajdi M. Zawia, Fadia Mohamed Gafri, Otman H. Abogress, Milad Salem Al. Habishi, Alhdi M. Zawia

Microbiology Research Journal International, Page 1-7
DOI: 10.9734/BMRJ/2016/24090

Aims: Staphylococcus aureus is a common cause of community and a hospital infection, methicillin-resistant Staphylococcus aureus (MRSA), is a common nosocomial infection pathogen, its resistance to multiple antibiotics has made it difficult to control. Healthcare workers are the most important source of MRSA nosocomial transmission in hospital. The main aim of our study is to determine the prevalence of MRSA, which was isolated from healthcare workers nasal carriage from different department of Tripoli center Hospital in Libya, as well as to determine the resistance of the MRSA isolates to commonly used antibiotics.

Study Design: This cross sectional study was carried out at central medical center of Tripoli. Informed healthcare workers from different department of Tripoli center Hospital in Libya participated in this study. The Nasal swabs samples of Health care workers were collected for microbiology screening for MRSA.

Place and Duration of Study: Samples were collected from Health care workers present in the different departments of Tripoli Centre hospitals from January– July 2013.

Methodology: A total of 408 nasal swabs of health care works in center Tripoli hospital were collected and microbiology laboratory investigation for positive results, which were identified as S. aureus that were mannitol fermenting colonies, gram-positive cocci, catalase positive and coagulase positive. The disc diffusion methods were used for antibiotic susceptibility test and methicillin resistance.

Results: The 408 nasal swabs samples were collected from healthcare workers out of which 64 (15.7%) isolated S. aureus and 14 (21.9%) MRSA. The highest MRSA rate was in samples collected from nurses (7.8%). About the department, the surgical wards and operating room had the highest rate of MRSA (28.6%) than other hospital department that participated in this study. The MRSA isolated from Health care workers were tested for antibiotic resistance, the result was erythromycin (75%), ciprofloxacin (70%), clindamycin (30%), trimethoprim/sulfamethoxazole (50%), quinuprisin/dalfopristin (20%), vancomycin (15%) and mupirocin (4%). The disk diffusion result indicated that 20% of those isolates had inducible resistance to clindamycin (MLSBi) and about 11% were characterized as having an MLSBc (constitutive) phenotype.

Conclusion: The results provide evidence that Libyan health care workers could serve as MRSA carriers and play a role in the dissemination of MRSA to the public and other workers.

Open Access Original Research Article

Molecular Characterization and Detection of Infection in Vector Snails of Urinary Schistosomiasis around Erinle and Eko Ende Dams in South West Nigeria

A. O. Hassan, A. O. J. Amoo, O. P. Akinwale, M. A. Adeleke, P. V. Gyang

Microbiology Research Journal International, Page 1-10
DOI: 10.9734/BMRJ/2016/9019

Aims: The prevalence of the schistosome cercariae in snail intermediate hosts has been known as one of the valuable predictors of the level of schistosomiasis transmission in different localities. This study was undertaken to determine molecular characterization and detection of infection in vectors snails of urinary schistosomiasis around Erinle and Eko-Ende Dams, South western Nigeria.

Study Design: Epidemiological survey.

Place and Duration of Study: Medical Microbiology and Parasitology Department, Obafemi Awolowo College of Health Science, Olabisi Onabanjo University, Sagamu, Ogun State, Nigeria between January 2010 and November 2012.

Methodology: The snails collected from communities around Erinle and Eko-Ende dams were identified using standard morphological keys. The infectivity of the Bulinus species by Schistosome was determined through cercaria shedding and Polymerase Chain Reaction (PCR) of amplification of Dra 1 gene repeats of S. haematobium while snail characterization was done using PCR-RFLP.

Results: Of the 277 snails screened, 78 (28.28%) were positive for cercaria shedding while 108 (38.98%) were positive for PCR screening. There was significant difference in the infectivity status determined by cercaria shedding and the PCR technique (p=0.05). All the snails characterized by PCR-RFLP were Bulinus. truncatus showing the species is involved in the transmission of urinary schistosomiasis in the study area.

The relatively high prevalence of schistosome infection in snail intermediate hosts around the two dams suggests active transmission of urinary schistosomiasis and underscores the need for integrated control in tackling the menace of the disease at the study area.