Open Access Short communication

Survey of Gram Negative and Gram Positive Bacteria in Drinking Water Supplies in Karachi, Pakistan

Farzana Abubakar Yousuf, Ruqaiyyah Siddiqui, Naveed Ahmed Khan

Microbiology Research Journal International, Page 592-597
DOI: 10.9734/BMRJ/2014/4887

More than 20,000 children die annually in the city of Karachi alone, majority of whose death are thought to be associated with waterborne pathogens. Drinking water and recreational exposure to polluted water pose a significant public health threat including gastroenteritis, paralysis, meningitis, hepatitis, respiratory illness and diarrhoea. The aim of this study was to determine the presence of bacterial contamination in drinking water supplies in Karachi, Pakistan. A total of fifty two domestic tap water samples were collected from different areas of Karachi, between May to June 2011 and analyzed for bacterial presence based on biochemical testing. The results revealed a high prevalence of Bacillus spp. (86.84%), followed by Pseudomonas spp. (57.14%), Citrobacter spp. (14.28%) Serratia spp., Enterobacteriaceae species (14.28%), Corneybacterium (10.52%), and Acinetobacter spp. (2.63%). These findings disclose bacterial contamination in drinking water supplies, many of which are pathogenic and can produce serious as well as life-threatening infections. Future studies will determine whether bacterial contamination of drinking water occurred post-source contamination. It is recommended that household water treatment interventions should be introduced to improve water quality

Open Access Short communication

Concurrent Infection of Torque Teno Sus Virus and Porcine Circovirus Type 2 in a Clinical Case with Post-weaning Multisystemic Wasting Syndrome

Shao-Lun Zhai, Jin-Xue Long, Qin-Ling Chen, Man-Lin Luo, Wen-Kang Wei, Shi-Shan Yuan

Microbiology Research Journal International, Page 607-615
DOI: 10.9734/BMRJ/2014/6336

Aims: The goal of this study was to identify possible concurrent infection of torque teno sus virus (TTSuV) and porcine circovirus type 2 (PCV2) in a clinical case with post-weaning multisystemic wasting syndrome (PMWS) on certain farm of Shanghai, China.

Place and Duration of Study: Department of Swine Infectious Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, between June 2009 and June 2010 & Institute of Animal Health, Guangdong Academy of Agricultural Sciences, between September and November, 2013.

Methodology: Multiply-primed rolling-circle amplification (MPRCA), a useful molecular tool, was performed to amplify genome sequence of TTSuV and PCV2. For serum sample of SH0822 from a clinical case with PMWS, the products of MPRCA were digested using EcoR I, Xba I, Sma I, Sac I, respectively. Moreover, Clustal W program (DNASTAR software) and MEGA 5.1 software (neighbour-joining method) was used to analysis its nucleotide homology and genetic relationship.

Results: Restriction digestion analysis showed one TTSuV genome-size fragment was presented in 1.2 % agarose gel, moreover, another PCV2 genome-size fragment was also presented. Nucleotide sequencing and phylogenetic analysis results suggested that its complete genome were 2823-nucleotide size and 1767-nucleotide size and they were divided into species TTSuV1b and genotype PCV2b, respectively.

Conclusion: Concurrent infection of TTSuV and PCV2 in a clinical case with PMWS was identified using MPRCA combining with restriction endonuclease digestion, which indicated that MPRCA was an effective tool to attain simultaneous detection and genome amplification of TTSuV and PCV2.

Open Access Original Research Article

Bacterial Colonization of Mechanical Ventilation Circuits in a Pediatric Intensive Care Unit

Daniela G. Moreira, Eitan Naaman Berezin, Marcelo Jenne Mimica

Microbiology Research Journal International, Page 598-606
DOI: 10.9734/BMRJ/2014/6153

To identify the onset time of bacterial proliferation in mechanical ventilator circuits in a pediatric intensive care unit (PICU) and the colonizing agents involved, as well to verify any possible pre-use contamination, we conducted a prospective microbiological analysis of the circuits of 30 patients, with a total of 342 cultures. Bacterial colonization of the mechanical ventilator circuits in the studied PICU was confirmed. Microorganisms were present in 39% of expiratory branch cultures: K. pneumoniae (77%), A. baumannii (65%), and S. aureus (42%). The inspiratory branch registered a smaller number of positive culture: A. baumannii (51%), S. aureus, coagulase-negative (38%) and K. pneumoniae (32%). As to the colonization onset time, 23% of the cultures collected on the 1st day from the inspiratory branch were positive, versus 30% of those collected from the expiratory branch, which lead us to conclude that bacteria can be present within the first hours of use. The sequential analysis of bacterial colonization over the course of circuit usage and the observation that the number of positive cultures becomes progressively higher on the 5th, 6th and 7th days in the expiratory branch both suggest that the systems should be replaced more often.

Open Access Original Research Article

Electrostatic and Water Content Effects on Yarrowia lipolytica Lipase Immobilization by Adsorption

Wazé A. Mireille Alloue-Boraud, Annick Lejeune, Rose Koffi-Nevry, Jacqueline Destain, Michel Paquot, Philippe Thonart

Microbiology Research Journal International, Page 640-653
DOI: 10.9734/BMRJ/2014/8004

Aims: In the present investigation, an attempt has been made to explain lipase immobilization by adsorption on three minerals matrixes, i.e. Celite 545, Silica gel (60G) and Avicel (PH 101).

Study Design: immobilization by absorption on minerals matrixes, water content by volumetric karl Fischer titration and surface potentials using a particle charge detector Mutek PCD 03 were used.

Place and Duration of Study: Walloon Centre of Industrial Biology (CWBI) Unit of Bio-Industries, University of Liege, Gembloux Agro-Bio Tech, Passage des Deportes 2, B-5030 Gembloux, Belgium between Jun 2012 and jun 2013.

Methodology: A methodical order was developed whereby the influences of water content, surface potentials and pH, on immobilization by adsorption were explored. Adsorbed YLL was used to understand an interesterification reaction between rapeseed oil and milk fat in comparison with a commercial silica-granulated Thermomyces lanuginosus lipase (Lipozyme TL IM).

Results: Maximum immobilization yield was obtained with Celite (70%) and the lowest with silica gel (29%). Total water content of free and immobilized lipase was determined by volumetric Karl Fischer titration. The water content of Silica gel was higher than the one of other supports. Water content of silica gel could prevent the enzyme fixation. These results could be explained by the adsorption being governed mainly by electrostatic interactions between the enzyme and matrix. This hypothesis was further reinforced by measurements of electrical potential. They showed a lowest negative potential of Silica gel after enzyme adsorption in comparison to Celite.

Conclusion: From these results celite was designated as an efficient matrix to immobilize Yarrowia lipolytica lipase (YLL) by adsorption. This performed system was used to realize an interesterification reaction between rapeseed oil and milk fat in comparison with a commercial silica-granulated Thermomyces lanuginosus lipase (Lipozyme TL IM).

Open Access Original Research Article

Exoenzymes Activity and Biofilm Production in Candida Species Isolated from Various Clinical Specimens in Benha University Hospital, Egypt

Enas Sh. Khater, Mohamed H. Al-Nory

Microbiology Research Journal International, Page 654-667
DOI: 10.9734/BMRJ/2014/7879

Background: The frequency of severe systemic fungal diseases has increased in the last few decades.

Aims: This study was done to speciate the candida isolates, to determine their antifungal susceptibility pattern and to detect biofilm formation and exoenzymes (phospholipase and proteinase) production.

Place and Duration of Study: This is a Six-months Cross sectional study conducted in ICU and Microbiology & Immunology departments, Benha University, Egypt

Methodology: The study was conducted on 75 Candida spp. isolated from various clinical samples of patients admitted in ICU. The Candida isolates were identified upto species level. Antifungal susceptibility testing was done by disc diffusion method. The biofilm formation was assessed by inoculating the isolates in conical polystyrene test tube containing Sabouraud’s dextrose broth supplemented with glucose. Proteinase activity was detected by using plates containing bovine serum albumin (BSA) agar. Phospholipase activity was detected by using egg yolk agar.

Results: Seventy five Candida spp. were isolated from different clinical samples. C. albicans was isolated from 39(52%) samples. Non-albicans Candida (NAC) spp. were isolated from 36 (48%) clinical specimens. Forty one (54.7%) out of 75 Candida species isolates obtained from the clinical isolates produced biofilm. Out of 39 C. albicans isolates 20 (51.3%) produced biofilm, while out of 36 NAC species isolates 21 (58.3%) produced biofilm. The number of total proteinase positive isolates were 50 (66.7%). C. albicans was higher than that of the NAC isolates (29 [66.7%] versus 21 [58.3%]). Phospholipase positive isolates of C. albicans was higher than that of the NAC isolates (32[82.1%] versus 37[49.3%]). All isolates were susceptible to amphotericin B and ketoconazole. Resistance to fluconazole was found in 8 isolates (22.2%) of NAC spp. and 2 isolates (5.1%) of C. albicans isolates.

Conclusion: The isolation of C. albicans were 39 (52%) in different clinical samples and isolation of NAC spp. were 36(48%). So NAC spp.  is no longer overlooked as these organisms are emerging pathogens. The number of NAC producing proteinase, phospholipase and biofilm are more than the number of C. albicans producing these virulence factors. The C. albicans and NAC showed 100% susceptiblity to amphotericin B  and ketokonazole while fluconazole showed resistance in 22.2% of NAC spp. and 5.1% of C. albicans isolates. All resistant Candida species to fluconazole were biofilm producers.

Open Access Original Research Article

Emergence of Third Generation Cephalosporin Resistance and Typing by Randomly Amplified Polymorphic DNA (RAPD) among Clinical Salmonella Isolates from Lagos, Nigeria

K. O. Akinyemi, B. A. Iwalokun, J. A. Agboyinu, O. Ogunyemi, A. K. Fasure

Microbiology Research Journal International, Page 668-677
DOI: 10.9734/BMRJ/2014/8507

Aims: To investigate emergence of cephalosporin resistance and clonal relatedness among clinical Salmonella isolates recovered from patients in Lagos, Nigeria.

Study Design: It is an investigative study. A total of 300 patients who presented with various types of medical conditions at prominent referral public hospitals were recruited.

Place and Duration of Study: Department of Microbiology, Lagos State University, Ojo, Lagos and  Nigerian Institute of Medical Research, Yaba, Lagos, Nigeria from  July 2011 to May 2012.

Methodology: Salmonella identification was done using standard methods. The isolates were subjected to antimicrobial susceptibility by disk diffusion method. The isolates were further screened for plasmid DNA and blaCTX-M carriage on plasmid using alkaline lysis and PCR methods. Clonal relatedness of the isolates was assessed by RAPD PCR using genomic DNA as template for three RAPD primers (784, 1254 and OPA4). The resulting RAPD types were determined by visualization and discrimination index was measured using a discriminating index calculator.

Results: Sixty three Salmonella isolates were recovered made up of five serovars. In all 49% of the isolates were resistant to cefuroxime, 46% to cefoxitin, 37% to cefriazone and 35% to ceftazidine. Interestingly 28(87.5%) of the 32 ESBL producing Salmonella isolates  possessed at least one or more  plasmids from five distinct  sizes recorded 2.5; 4; 9; 15;23.5kb. Four distinct RAPD profiles were exhibited by the test strains.  The total discriminatory power among the isolates was 0.77 (77%).

Conclusion: Third generation cephalosporin resistance involving blaCTX-M has emerged among clinical Salmonella isolates in Lagos. RAPD elicits potential as a cost-effective and time saving tool for local discrimination of clinical Salmonella isolates for epidemiological purposes.

Open Access Original Research Article

The Possibility of Using Fibers as a Prebiotic in Making of Probiotic Based On-Some Dairy Products

Gehan H. Bisar, Kh. El-Saadany, A. Khattab, Wedad M. El Kholy

Microbiology Research Journal International, Page 678-697
DOI: 10.9734/BMRJ/2014/8587

Probiotic microorganisms were found to affect the host health beneficially when found in an a certain count not less than 106 CFU/g (Colony-forming unit / gram), and they have some benefits as protection from cancer, relief of lactose intolerance, reduce the risk from diarrhea, normalize the bowel movement, and enhance the immune functions, reduce cholesterol level and reduce the risk of eczema. This study was carried out to examine some of fibers and polysaccharide for their assimilation by some lactic acid bacterial strain specially known for their probiotic effect. It was concluded from the present study the following: studying the capability of Esherichia coli (E. coli), bifidobacteria and 9 strains related to lactic acid bacteria included in assimilating 7 different (polysaccharides, fibers and other materials) included (Polydextrose, Maltodextrine, inulin, prolia, resistant starch, wheat fiber and gumarabic) when substituted with dextrose inde Man, Rogosa and Sharpe (MRS) broth and incubated at their optimal temperature. The results revealed that the examined culture were varied in their assimilation of the 2% polysaccharides tested, furthermore maltodextrin, showed a good assimilation by Bifidobacterium longum ATCC 15707 (B. longum) and Lactobacillus acidophilus NRRLB1910 (L. acidophilus). The effect of certain concentrations (2, 3and 4%) of the selected (polysaccharides, fibers and other materials) on the growth activity of the lactic acid bacterial cultures tested in addition to E. coli (as a representative for coliform bacteria). The results revealed that upon increasing the concentration of the selected polysaccharides there was a remarkable decrease in pH compared to E. coli which showed contrast outcomes on which its pH were significantly higher than the tested bifidobacteria and lactic acid bacteria. Studying the effect of incubation duration and it’s relation on the selected (polysaccharides, fibers and other materials) assimilation by the tested lactic acid bacterial cultures. Results revealed that there is a direct proportion relation between long incubation timing and polysaccharide assimilation (indicated by decrease in pH). This decrease was very clear at 24 hours of incubation at the optimum temperature for each strain.  Upon studying the antagonistic effect between E. coli with B. longum ATCC 15707, L. acidophilus NRRLB 1910 and Lactobacillus reuteri B 14171 (L. reuteri) grown on modified MRS with 3% of each polysaccharide (polydextrose, maltodextrin and inulin). The change in the growth of these cultures combinations were determined by counting on MRS and Violet red bile agar (VRBA). It was shown that these (polysaccharides/fibers) challenged the growth of the probiotic bacteria and the count of E. coli (wild) E.W was lowered significantly due to the inhabitation effect of the used probiotic bacteria. It was concluded that good results was shown from using the three polysaccharides/fibers (maltodextrin, inulin andpolydextrose) that was elected to base the rest of work on.

Open Access Original Research Article

Optimization of Culture Conditions for the Production of Extracellular Cellulases via Solid State Fermentation

Dina H. I. El-Ghonemy, Thanaa H. Ali, Maysa E. Moharam

Microbiology Research Journal International, Page 698-714
DOI: 10.9734/BMRJ/2014/8100

Aim: The aims of the present study were to screen different filamentous fungi for extracellular cellulases production and to optimize solid-state fermentation medium and culture conditions to enhance cellulases production.

Study Design: Using agro-industrial waste as raw material for the production of cellulases by a hyper cellulase producing fungus and evaluating the influence of various parameters to design a suitable SSF process for cellulase production.

Place and Duration of Study: Department of Microbial Chemistry, Genetic Engineering and Biotechnology Division, National Research Centre (NRC), Cairo, Egypt, between January 2013 and October 2013.

Methodology: Different filamentous fungi were grown and maintained on potato dextrose agar slants at 28ºC for 7 days. The spores were washed down by distilled water. Then, 2.0 ml aliquots were used to inoculate 250 ml Erlenmeyer flasks, containing rice straw as the only carbon source. The inoculated flasks were incubated for 5 days at 28ºC. The enzymes were extracted by mixing homogenously the fermented substrate with 50 ml citrate phosphate buffer (0.1 M, pH 5.0) and agitated (150 rpm) for 1 hr. Pooled extracts were centrifuged at 5000 rpm for 15min and the clear supernatant was used as a source of extracellular enzyme.

Results: Aspergillus oryzae NRRL 3484 exhibited relatively higher cellulases production. The optimum incubation period, temperature, and initial moisture level were reported on the 7th day, at 28°C, and 70%, respectively. Peptone proved to be the suitable nitrogen source followed by yeast extract, while pH 5.0 was ideal for cellulases production.

Conclusion: Using ligninolytic fungi, including their enzymes, may be one potential alternative to provide a more practical and environmental-friendly approach for enhancing the nutritive value of rice straw. Moreover, the application of ligninolytic fungi or their enzymes combined with chemical pre-treatments to rice straw may be an alternative way to shorten the period of the incubation times and (or) decrease the amount of chemicals, effecting some synergy.

Open Access Original Research Article

Microbiological Characterization and Physicochemical Properties of Sudanese Honeys

Mohammed Y. Musa, Ahmed E. Elfaki, Seif Eldin. A. Mohammed

Microbiology Research Journal International, Page 715-722
DOI: 10.9734/BMRJ/2014/5330

Aim:  Honey is not always a safe product and in some instances it is spoiled by the growth of micro-organisms. The aim of the study was to characterize honey on biological and physicochemical basis.

Study Design: Determination of the microbial loads in the Sudanese honey brands and characterization of their physicochemical properties.

Methodologies: Several microbiological tests were employed for the determination of the microbial loads. The methods of Association of the Official Analytical Chemists were employed for the physicochemical properties.

Results: The microbiological tests were negative for Escherichia coli, and total coliforms (mpn/ml). Few honey brands contained Clostridium botulinum, Salmonella, Staphylococcus aureus, yeasts and moulds. The maximum total viable bacteria count was > 3.77 log. cfu/ml. The results of the physical parameters tested were as follows: pH 3.6, specific gravity 1.2, viscosity 120.7 Poise, and refractive index 1.4.,  moisture 18.2%, acidity 54.2 (meq/kg), total sugars 70.5%, fructose 32.1%, glucose 32.8%, and sucrose 5.5%.

Conclusion: The physicochemical properties of the investigated samples comply with the Codex Alimintarius Standards for honey. However, some honey brands contained yeasts, moulds, as well as some pathogenic bacteria such as Salmonella spp, Staphylococcus aureus, Clostridium botulinum. Thus the study justified the importance of the proper processing condition of the honey such as the hygiene of beekeepers and beekeeping tools, pasteurization or irradiation of the honey


Open Access Review Article

Taxonomy of the Rhizobia: Current Perspectives

Halima Berrada, Kawtar Fikri-Benbrahim

Microbiology Research Journal International, Page 616-639
DOI: 10.9734/BMRJ/2014/5635

The classification of rhizobia has been gone through a substantial change in recent years due to the addition of several new genera and species to this important bacterial group. Recent studies have shown the existence of a great diversity among nitrogen-fixing bacteria isolated from different legumes. Currently, more than 98 species belonging to 14 genera of α- and β- proteobacteria have been described as rhizobia. The genera Rhizobium, Mezorhizobium, Ensifer (formerly Sinorhizobium), Bradyrhizobium, Phyllobacterium, Microvirga, Azorhizobium, Ocrhobactrum, Methylobacterium, Devosia, Shinella (Class of α-proteobacteria), Burkholderia, Cupriavidus (formerly Ralstonia) (Class of β-proteobacteria) and some γ-proteobacteria, form the set of the bacteria known as legume’s symbionts. There is certainly much to discover, since only 23% of known legumes were identified specifically for symbiotic relationship up to date. The discovery of new symbionts associated with legumes is necessary to gain deep insight into the taxonomy of the rhizobia. A literature review of the currently recognized classification of rhizobia is presented in this paper.