Open Access Original Research Article

Characterization of Vaginal Lactobacillus Strains and Their Potential Antagonistic Effects on Candida albicans

Shuai Wang, Qiangyi Wang, Bingbing Xiao, Rui Zhang, Ben Wang, Qinping Liao, Hui Zhuang, Tong Li

Microbiology Research Journal International, Page 185-195
DOI: 10.9734/BMRJ/2015/15116

Aims: To characterize Lactobacillus strains for potential beneficial effects, especially for inhibition of Candida albicans growth.
Materials and Methods: Twelve vaginal Lactobacillus strains belonging to five species from our laboratory collection were studied. The acid production and hydrogen peroxide (H2O2) production were determined. The biofilm formation ability was measured by a semi-quantitative microtiter plate assay. Besides the detection of autoaggregation and coaggregation capacities with C. albicans using a spectrophotometric assay, aggregating clusters were observed by light microscopy. The spot inhibition, agar overlay and Oxford Cup methods were used to test antagonistic activities of Lactobacillus strains against C. albicans.
Results: Seven strains of L. fermentum (A011, A024, A025, A035, A041, A044 and A081) and L. salivarius A023 were revealed to decrease the medium pH below 4.5 just within six hours due to the rapid growth. L. jensenii A083 and L. gasseri A054 were the best biofilm formers in polystyrene plates, whereas the other ten strains could form biofilm with varying affinities. In addition to significant H2O2 production found in L. jensenii A083, L. crispatus A014 and A055, these strains showed strong autoaggregation and coaggregation abilities with C. albicans (ATCC 90029 and Z03). L. salivarius A023, L. fermentum A025 and L. crispatus A014 displayed strong activities against C. albicans in spot inhibition and agar overlay assays.
Conclusion: The potential beneficial properties of Lactobacillus spp. were strain specific. Among the tested strains, L. salivarius A023, L. fermentum A025 and L. crispatus A014 might be better candidates for further investigation on the inhibition of C. albicans growth.

Open Access Original Research Article

Antibiotic-Resistant Enterococcus faecalis Isolated from Food Canteens in Osun States, Nigeria

A. K. Olawale, R. J. Salako, A. O. Olawale, O. Famurewa

Microbiology Research Journal International, Page 196-206
DOI: 10.9734/BMRJ/2015/7348

Enterococci have continued to attract considerable importance and attention as pathogens of public health concern both in the hospital and environmental settings. Therefore epidemiological studies of these organisms are now a major research interest. Incidence of multiple antibiotic resistance (MAR) among Enterococcus faecalis recovered from food canteens in Osun States, Nigeria was investigated. In all, 537 samples from canteens including; foods, plates and hand swabs of food handlers, were examined for contamination by E. faecalis. Out of 658 E. faecalis strains recovered from the samples, 71.30% were resistant to cloxacilin, 70.21% to erythromycin, 68.54% to cotrimoxazole, 65.05% to amoxicillin, 65.05% to chloramphenicol, 63.68% to tetracycline, 61.70% to augmentin, 53.04% to gentamicin and 11.7% to vancomycin. Resistance to the fluoroquinolones tested was in the order levofloxacin (34.04%), ciprofloxacin (28.72%), norfloxacin (26.6%), spafloxacin, (24.92%), and perfloxacin (24.32%). About 99.2% of the isolates were multiple resistant to between three and 12 of the antibiotics tested. The most common MAR phenotype was AMX/TET/COT/CLX/GEN/CLO/AUG/LEV/CIP/NOR. Of the ten medicinal plants investigated for antimicrobial activity on selected E. faecalis isolates, sweet acacia (Acacia farneciana) possessed the highest antibacterial activity. Crude methanol extract was most potent than the others (ethanol and aqueous extracts); an indication that the methanol extract probably possessed some active components not contained in the other extracts. This study has revealed that foods vended from a number of canteens and food outlets in Osun State, Nigeria were contaminated with antibiotic-resistant E. faecalis suggesting a possible significant reservoir of antibiotic-resistant bacteria. Hence, urgent and periodic epidemiological evaluation and enforcement of good hygiene practices in the study area are essential. Plant extracts were very effective on AR E. faecalis. Further studies on these plant extracts may provide evidence to confirm their roles as alternatives for the treatment and or control of E. faecalis-associated diseases.

Open Access Original Research Article

Isolation and Identification of Bacteria from Transformer Oil Contaminated Soil

Aziz ur Rehman Safi, Subhanullah ., Muhammad Ayaz, Attaullah ., Baharullah Khatak, Noor Ul Akbar, Imran Khan, Muhammad Asif, Nasar Khan, Sami Ullah

Microbiology Research Journal International, Page 207-214
DOI: 10.9734/BMRJ/2015/11278

Background: Poly chlorinated biphenyls (PCBs) are organic chemicals with toxigenic, carcinogenic affecting human health and the environment using as dielectric fluids in transformers as a cooling and insulating medium containing.
Materials and Methods: Soil samples were collected from transformer oil contaminated soil at different workshops in three different districts of Khyber Pakhtunkhwa i.e. Peshawar, Nowshera and Kohat and were kept at 4°C before analysis.
The samples were subjected to Pure culture isolation through a selective medium (Medium A). After incubation for 24 to 48 hours at 37°C with 1% transformer oil as sole source of carbon, the isolates were examined for their colony size, shape, margin, consistency, opacity, elevation and pigmentation; while Gram reaction and cell morphology were examined microscopically. Furthermore the biochemical tests were also done for identification of the bacteria.
Results: A total of 14 isolates were obtained from all the transformer oil contaminated soil samples after examining the samples indicates the bacteria namely Bacillus, Micrococcus, Pseudomonas, Acinetobacter and Staphylococcus were identified during the current study.
Conclusion: Based on the results of the study, five bacterial species capable of degrading PCBs in transformer oil, from which it was concluded that PCB compounds can be degraded by some microorganisms under aerobic conditions.

Open Access Original Research Article

Sourcing Starter Cultures for Parkia biglobosa Fermentation III: Preparation of Starter Cultures for Industrial Scale Fermentation

E. Y. Aderibigbe, W. Visessanguan, D. Jureeporn

Microbiology Research Journal International, Page 215-224
DOI: 10.9734/BMRJ/2015/15761

Aim: To prepare starter cultures for industrial-scale fermentation of Parkia biglobosa, using two strains of Bacillus species, 2B and BC4333.
Study Design: Three substrates, African locust bean (ALB), soybean meal (SBM) and de-hulled soybean (SB) were tested for propagation of the bacteria. Four powdered materials, SBM, SB, ALB and Starch (STA) were tested as diluents/carriers for the starter cultures.
Place and Duration of Study: Food Biotechnology Research Unit, National Center for Genetic Engineering and Biotechnology (BIOTEC), Pathumthani, Thailand, between June and August, 2011.
Methodology: Microbial load, with respect to standard plate count and spore count of milled, dried starter cultures was determined. The potency of the starters to effect fermentation of beans was screened by starter-culture fermentation. Products were analyzed for sensory evaluation, total microbial load and pH.
Results: The three substrates, ALB, SBM and SB were found suitable for the propagation of the 2 strains of Bacillus, 2B and BC4333 as starter cultures. The starter cultures can be dried at 60°C for 24h and milled using sterile dry-mill blender. Powdered ALB, SBM, SB and starch were also suitable diluents/ carriers for the stock starter cultures. However, on the basis of physical appearance of products, starch is a preferred carrier.
Conclusion: The dried starter culture preparations can be used as inocula for large scale fermentation at ratio ranging: 1 g starter: 33 kg to 1 g starter: 1000 kg of African locust bean substrate.

Open Access Original Research Article

Differentiation in a Single-Tube PCR between Leishmania mexicana and Leishmania braziliensis in Clinical Samples

Victor Monteon, Enrique Quen-Ramirez, Román Diaz-Arce, María Vargas, Ruth López, Lidia Baylon, José L. Rosales

Microbiology Research Journal International, Page 225-235
DOI: 10.9734/BMRJ/2015/12418

Aim: To assess the usefulness of a single-tube PCR end point for differentiating between Leishmania and Viannia subgenera in clinical samples of cutaneous leishmaniasis.
Methodology: Impression smears of 65 patients from Campeche State, Mexico with leishmaniasis-like lesions were analyzed by conventional Giemsa staining and a new simple PCR end point with primers named LU-5A designed by [Harris et al.1998] and LME (designed for this study and based on a mini-exon of L.(L) mexicana,GenBankX64317.1). This PCR generates an amplicon of 210 and 270 bp with L. (L) mexicana (MHOM/MX/84/SETGS) and 230 bp with L. (V) braziliensis (MHOM/BR/75/M2903).
Results: Out of 65 impression smears of clinical samples 50 were positive according to PCR (76.9%) and 29 were positive according to microscopic observation (44.6%). The primers did not hybridized with human, Trypanosoma cruzi, Staphylococcus aureus, Staphylococcus epidermidis or Pseudomona aeruginosa DNA. Of the positive smears, 84% (42/50) corresponded to L. (L) mexicana and 16% (8/50) to L. (V) braziliensis.
Conclusion: A one-step PCR with primers LU-5A and LME improves the diagnostic capacity to differentiate between Leishmania and Viannia subgenera in parallel with conventional tests.

Open Access Original Research Article

Microbial Contamination and Antibiotic Resistance in Enteric Pathogens Isolated from Cooked Foods Sold in Eateries in Ado-Ekiti, Nigeria

O. A. Oluyege, O. Famurewa

Microbiology Research Journal International, Page 236-246
DOI: 10.9734/BMRJ/2015/7351

Background: There are indications that some ready-to-eat or street vended foods are of low microbial quality with varying degree of contaminations. The contaminants may include antibiotic-resistant bacteria that may further be spread through consumption of such foods which has epidemiological and public health implications. This study therefore, was aimed at investigating the microbial quality of ready-to-eat cooked foods sold in eateries in Ado-Ekiti, Nigeria and to determine the susceptibility of the isolates to antibiotics.
Methods: We evaluated bacterial contamination of ready-to-eat cooked foods using total bacteria plate counts (TPC) and total coliform counts (TCC). Susceptibility of isolates to antibiotics was tested using the disc diffusion method.
Results: The overall mean TPC and TCC of cooked food samples ranged from 4.96±1.01 log10 cfu/g to 5.34±0.06 log10 cfu/g for both. There was no significant difference (≤ 0.05) in the overall mean TPC and TCC of the various cooked food samples from the three categories of sampling sites. The cooked foods examined were contaminated with a total of 129 enteric bacterial species belonging to 7 genera with E. coli (31.8%) being the most prevalent, followed by Klebsiella sp. (19.4%), Proteus sp. (17.1%), Salmonella (14.0%), Pseudomonas sp. (12.4%), Shigella sp. (3.8%) and Enterobacter sp. (1.6%) in that order. Resistance to antibiotics was very high (94.0%) and resistance to amoxicillin (89.1%) was the highest, and least to nalidixic acid (23.1%) while none of the isolates was resistant to ofloxacin. More than 50% of these isolates were resistant to six of the eight antibiotics tested and 26 different antibiotic resistance phenotypes were obtained. The most common phenotype observed was AMX/GEN/AUG. The results suggest that contaminated ready-to-eat (RTE) food sold in eateries can be a major source of antibiotic-resistant organisms in the study area.
Conclusion: Most of the food samples investigated was contaminated in varying degrees with pathogenic, opportunistic pathogenic bacteria and other bacterial indicators of contamination. There was an overall high rate of resistance to antibiotics with equally high rate of multiple antibiotic resistance (MAR) among the bacterial contaminants. This portent high risks of further spread of antibiotic resistance in the community and environment. Further study will hopefully help to determine the presence of resistance genes and or mode of resistance among the MAR organisms.