Open Access Original Research Article

Mutagenesis and Immobilization Effect on Exopolysaccharide Production by Weissella confusa and Lactobacillus delbrueckii

Racheal Oluwayemisi Ishola, Bukola Christianah Adebayo-Tayo

Journal of Advances in Microbiology, Page 1-10
DOI: 10.9734/JAMB/2018/40686

Aims: This work aimed at investigating the effect of mutation and immobilization on EPS production and to characterize the EPS produced by L. delbrueckii and Weissella confusa.

Study Design: To determine the effect of mutation using UV irradiation and immobilization using different matrixes on EPS production by the strains and to characterize the EPS produced.

Methodology: Weissella confusa and Lactobacillus delbrueckii was exposed to UV irradiation and the wild and mutants strains was immobilized. The immobilized wild and mutants was used for EPS production. The produced EPS was characterized.

Results: The LAB count that survived the UV irradiation reduced as the exposure time increases. The Wild L. delbrueckii produced more EPS (583.72 mg/L) than its mutant strain (581.42 mg/L). However, wild Weissella confusa and wild Lactobacillus delbrueckii produced more EPS than the mutant strain. Production of EPS by wild and mutant Weissella confusa immobilized in Sodium alginate (WWCNA and WWCNA), agar matrix (WWCAA and MWCAA) and polyurethane foam (WWCPF and MWCPF) ranged from 240.25 – 544.28 mg/L with WWCPF producing the highest EPS. Production of EPS by wild and mutant L. delbrueckii immobilized in Sodium alginate (IWLDNA and IMLDNA), agar matrix (IWWCAA and IMLDAA) and polyurethane foam (WLDPF and MLDPF) ranged from 220.06 – 502.81 mg/L with IWLDPF producing the highest EPS. However, immobilization in agar matrix supported the least EPS production. Characterization of the EPS using FT-IR spectroscopy confirmed the presence of the different degrees of functional groups which indicates that they are polysaccharides, thus confirming the EPS. Un-immobilized Weissella confusa had the highest EPS production (558.72 mg/L and 583.61 mg/L) compared to the immobilized strains.

Conclusion: Immobilization of mutant L. delbrueckii and Weissella confusa using polyurethane foam supported EPS production.

Open Access Original Research Article

The Effect of pH and Temperature on Phenol Coefficients of Two Common Disinfectants Using Clinical Isolates of Escherichia coli and Staphylococcus aureus

Chukwuebuka M. Ononugbo, Eleazar E. Reward, Anthony C. Ike

Journal of Advances in Microbiology, Page 1-7
DOI: 10.9734/JAMB/2018/41376

Aims: The aim of this study is to evaluate the efficacy of two disinfectants, Jik and Roberts, under use-conditions against some hospital isolates using their phenol coefficient.  The effects of pH and temperature on the phenol coefficients were also tested. Phenol coefficient still remains a valuable means of determining the effectiveness of disinfectants, even though phenol is no longer commonly used for disinfection.

Materials and Methods: Bacteria were isolated and identified using standard microbiological procedures from samples collected from the skin of patients and hospital environments like beddings, floors and trawlers. A 5% (w/v) solution of phenol and 5% (v/v) solution of disinfectants were used for determination of their phenol coefficients on standardized organisms containing about 1.5x108 cfu/ml. The effect of temperature was determined at 4ºC and 45ºC, while that of pH was determined at pH 1 and 13.

Results: The results showed that Staphylococcus aureus was more susceptible to both disinfectants. Jik had a higher phenol coefficient for the test organisms (16 and 8) compared to Roberts (4 and 2) for S. aureus and Escherichia coli respectively. Both temperature and pH had a direct effect on the antibacterial activities of the disinfectants. The phenol coefficient was higher for both organisms at 45ºC than at 4ºC for Roberts. In the case of Jik, the phenol coefficient reduced as the temperature was increased to 45ºC.  At pH 13, Jik gave a higher phenol coefficient, while Roberts gave a higher phenol coefficient at pH 1.

Conclusions: Temperature enhances the performance of Roberts but has a negative effect on that of Jik. Roberts performs better at acidic pH while Jik performs better at alkaline pH. For disinfection purposes, it is recommended that different types of disinfectants be employed in the rotation to help prevent the development of resistant strains of microorganisms.

Open Access Original Research Article

Antibacterial and Antioxidant Activity of Herbal Extracts of Curcuma longa L., Careya arborea Roxb., Madhuca longifolia (Koenig) Macbr. and Punica granatum L.

T. S. P. Jayaweera, G. M. P. J. Bandara, U. N. N. Udawatta, H. A. D. Ruwanjith, H. A. D. Ruwandeepika

Journal of Advances in Microbiology, Page 1-12
DOI: 10.9734/JAMB/2018/41159

Aims: Development of multiple resistances against pathogenic bacteria has become a global concern at the moment. This problem has enforced scientists to search for new antimicrobial substances from various sources including medicinal plants. Hence the study was designed to determine the effect of ethanol extracts of commonly used some herbs rhizomes of Curcuma longa, bark of Careya arborea, seed of Madhuca longifolia and leaves of Punica granatum at different levels of concentrations (125, 100, 75 and 50 mg/ml) in Sri Lanka on (Salmonella typhimrium (ATCC 14028), Bacillus subtilis (ATCC 6633) and Escherichia coli (ATCC 25922)).

Study Design: This is a laboratory-controlled experimental design.

Place and Duration of Study: Laboratory of Livestock Production, Faculty of Agricultural  Sciences and Laboratory of Chemistry, Faculty of Applied Sciences, Sabaragamuwa University of Sri Lanka.

Methodology: Ethanol herbal extracts at four different concentrations (125, 100, 75 and 50 mg/ml) were screened for its antimicrobial activity by Kirby-Bauer disc diffusion assay method. In vitro, the antioxidant ability was determined using 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging assay method.

Results: Punica granatum showed the highest inhibition against S. typhimrium; 15.46±0.1, 14.71±0.14, 13.11±0.06 and 11.81±0.09 mm at 125, 100, 75 and 50 mg/ml concentrations respectively. Careya arborea showed the highest inhibition against B. subtilis with inhibitory zones of 10.34±=0.12, 9.22±0.25, 7.55±0.15 and 7.05±0.05 mm and second highest inhibition was against E. coli; 12.89±0.07, 12.43±0.10, 11.34±0.19 and 10.67±0.08 mm for all concentrations respectively. Careya arborea exhibited the highest inhibition against B. subtilis with inhibitory zones of 10.34±=0.12, 9.22±0.25, 7.55±0.15 and 7.05±0.05 mm. When considering the effect of Curcuma longa, B. subtilis and E. coli had shown significant highest inhibition at 125 mg/ml and S. typhimurium had lowest inhibition. Highest antimicrobial effect on B subtilis (7.49±0.31 mm) was shown by the ethanolic extract of M. longifolia (125 mg/ml) compared to other two bacteria (for S. typhimrium, 6.53±0.18 mm and E. coli 6.67±0.18 mm). Careya arborea exhibited the highest ascorbic acid equivalent antioxidant concentrations (718.40±22.78 mg ascorbic/g extract) followed by Punica granatum (213.43±17.82 mg ascorbic/ g extract) and Curcuma longa (144.28±6.40 mg ascorbic/g extract). Madhuca longifolia had lowest (4.11±0.27) and inhibitory concentration at 50% (IC50) of DPPH radical scavenging activity (2.84±0.08, 9.62±0.76, 14.14±0.61 and 498.01±34.63 IC50 µg/ml) in the ethanol extracts of Careya arborea, P. granatum, C. longa and Madhuca longifolia respectively.

Conclusion: This study concluded that there was a significant antimicrobial effect in ethanol extracts of tested herbs against S. typhimurium (ATCC 14028), B. subtilis (ATCC 6633) and E. coli (ATCC 25922) at varying levels.

Open Access Original Research Article

Occurrence of Multidrug Resistant Staphylococcus aureus and Klebsiella pneumoniae Isolated from Clinical and Environmental Samples in Ondo State, Nigeria

Ojokoh, Anthony Okhonlaye, Ojo, Martha Oluwatosin

Journal of Advances in Microbiology, Page 1-10
DOI: 10.9734/JAMB/2018/40204

Introduction: Antibiotic resistant bacteria are threat to our community and hospital settings. Multi drug resistance in Klebsiella pneumoniae and Staphyloccous aureus can cause a wide range of infections, including pneumoniae, urinary tract infection and bacteremia which can lead to substantial morbidity and mortality.

Aims: To study multidrug resistance patterns of K. pneumoniae and S. aureus isolated from clinical (urine and post-operative wound) and environmental (air in hospital environment, market soil and well water) samples in Ondo State.

Place and Duration of Study: Sample: Department of Microbiology, Federal University of Technology, Akure, between November 2016 and July 2017.

Methodology: Collection of all the samples, isolation of K. pneumoniae and S. aureus and antibiotic susceptibility test were carried out using standard microbiological methods.

Results: S. aureus and K. pneumoniae counts were observed in Ondo North (wound; 50.20±0.00 ×104cfu) and Ondo central (well water; 42.33 ± 0.03×104cfu/ml) senatorial district respectively. K. pneumoniae recovery rate are; 23(23.71%) from market soil, 20(11.30%) from post-operative wound, 26(10.36%) from urine, 40(38.36%) from market well water and 13 (21.31%) hospital air while S. aureus was most prevalent in post-surgical wound 50 (28.25%). In Ondo north, K. pneumoniae isolates were at least 68% resistant to septrin, chloramphenicol, amoxacillin, and sparfloxacin while in south they were 70% resistant to septrin, chloramphenicol and amoxicillin however, all S. aureus isolates were 100% resistant to amoxicillin and were at least resistant to five different antibiotics. K. pneumoniae isolated from post-operative wound have resistance pattern of Septrin (71%), Chloramphenicol (13%), Amoxacillin (56%) and Sparfloxacin (56%) and in market soil the resistance pattern are; Augumentin (98%), Pefloxacin (99%), Septrin (98%), Chloramphenicol (97%), Gentamicin (100%), Ofloxacin (98%), Amoxacillin (98%), ciprofloxacin (98%), Sparfloxacin (98%) and Streptomycin (100%). All S. aureus isolated from urine samples were 100% resistant to streptomycin, chloramphenicol, ceftriazone, erythromycin, cotrimoxazole and Gentamicin.

Conclusion: Occurrence of these multidrug resistance K. pneumoniae and S. aureus in clinical and environmental samples could result into increase in morbidity and mortality.

Open Access Original Research Article

Probiotic Properties of Lipolytic Bacteria Isolated from Fermented Food and Dairy Products

Madhu Rathore, Kanika Sharma

Journal of Advances in Microbiology, Page 1-7
DOI: 10.9734/JAMB/2018/40269

Aims: Present study deals with the isolation and probiotic characterization of lactic acid bacteria purified from fermented food and dairy products.

Study Design: This study designed to isolate, identify, and in vitro characterization (low pH/high bile salt tolerance, antibacterial activity, and antibiotic susceptibility).

Place and Duration of Study: Microbial Research Laboratory, Department of Biotechnology, Mohanlal Sukhadia University, Rajasthan. Between November 2017 to January 2018.

Methodology: The ability of the isolates to survive in the presence of hydrochloric acid (pH 1.0 and pH 3.0), pepsin (3 mg/ml, pH 2.0), pancreatin (1 mg/ml, pH 8.0) and bile salts (0.3% w/v Ox Gall) was measured. The intrinsic antimicrobial activity of cell-free extract from selected LAB isolates against E. coli, Pseudomonas aeruginosa, Bacillus subtilis, Proteus vulgaris and Staphylococcus aureus were determined by agar well method. 

Results: Among the 7 bacterial isolates purified, 6 were from dairy and fermented food samples whereas 1 isolates were used as standard purified from Yakult (known probiotic drink). Isolates were checked for the presence of lipid degrading principle, maximum activity was observed in Lactobacillus helveticus purified from pickle (a fermented food). Probiotic characterization profiling suggested that Lactobacillus helveticus (pickle), Lactobacillus Plantarum (unfermented camel milk) and Pediococcus pentosacceos (Dosa batter) showed a good potential of probiotic as compared to other isolates.

Conclusion: Furthermore characterization of these isolates and subsequent clinical studies will pave the way to design a novel probiotic formulation based on fermented food and camel milk.