Microbiology Research Journal International

Essential oils (EOs) are commonly used in food industry, due that they possess antioxidative and antimicrobial properties. There are few essential oils that have been used in medicine, due to its potent antibacterial activity against intrahospital pathogens. OEO has experimentally shown potent antibacterial effect on nosocomial Gram-positive bacteria, therefore it can be very useful in hospital environments, where there are many bacterial pathogens, which are the etiological agents of nosocomial infections and most of them are resistant to several antibiotics.

Objective: The aim of this study was to determine antimicrobial effect of OEO on most frequent bacterial intrahospital pathogens: MRSA, MRSE comparatively to selected ATCC bacterial reference strains.

Methods: This experimental study investigates the antibacterial action of oregano (Origanum vulgare) essential oil (OvEO) on two human pathogens: Staphylococcus aureus (SA) and Staphylococcus epidermidis (SE) Here, we used OEO against one of the most prominent antibiotic-resistant bacterial strains: methicillin-resistant SA (MRSAmecA+ = Meticillin Resistant SA and mecA- = Meticillin Resistance SA ), methicillin-resistant SE (MRSEmecA+ = Meticillin Resistance Staphylococcus epidermidis mecA+) and reference strains: S. aureus ATCC 700699, S. epidermidis ATCC 359845 and E. coli ATCC 25922. Bactericidal effects of the OEO on these bacteria were mainly evaluated using undiluted and four serial dilutions in coconut oil (CCO) l: 1:10, 1:100, 1:200, 1:400.

Results: OEO, undiluted and 4 serial dilutions showed potent antibacterial activity against all strains tested. In conclusion, this OEO could be used as an alternative in medicine. The ability of OEO to inhibit and kill clinical Multi-Drug-Resistant (MDR): MRSA and MRSE strains, highlights it´s potential for use in the management of drug-resistant MDR infections in hospitals wards.

Dermatophytes are responsible for ringworms that are very often found on the heads of children in Africa. In Côte d'Ivoire, ringworms have been the subject of several studies revealing fairly high frequencies.

Aims: The present work consisted essentially in studying the antifungal activity of the barks of Pericopsis laxiflora, a plant from the Ivorian pharmacopoeia on germs responsible for ringworm.

Methodology: The 70% hydroethanolic extract of the bark of Pericopsis laxiflora was prepared and tested on Trichophyton mentagrophytes and Trichophyton rubrum. In addition, by staining and precipitation tests, phytochemical sorting was carried out on this extract.

Results: Faced with the hydroethanolic extract, Trichophyton mentagrophytes recorded a Minimun Inhibitory Concentration (MIC) which is equal to the Minimun Fungicidal Concentration(MFC) (MIC = MFC = 6.25 mg/mL). For the fungal strain of T. rubrum, the MFC obtained (100 mg/mL) was twice the MIC (50 mg/mL). The phytochemical study of this extract revealed the presence of sterols and polyterpenes, flavonoids and catechic tannins.

Conclusion: The results suggest that P. laxiflora extract could therefore be useful in the fight against dermatophytes.

Background: Low Density Polyethylene (LDPE) are plastic materials extensively used in packaging, constituting recalcitrant environmental pollutants that defy natural degradation processes.

Aim: This study isolated bacteria from a Nigerian environment and assessed their potential for LDPE biodegradation.

Methods: Using standard procedures, Bacteria were isolated from polythene samples collected from farmlands and waste dump sites in Nsukka metropolis. Mineral salt medium (MSM) was prepared, with LPDE as sole carbon source, and used for isolation. Optical density (OD₆₀₀ nm) was used to study bacterial growth on LDPE as sole carbon source as proof of biodegradation. Both organisms demonstrated steady growth on LDPE over time.

Results: Pseudomonas aeruginosa and Micrococcus sp. were identified based on morphological and biochemical characteristics. Ability to grow on LDPE as a sole carbon source was studied as evidence of polyethylene biodegradation. Organisms were inoculated into MSM and incubated at 37°C and 50°C for 15 days. Maximum growth was recorded after 15 days of incubation for both organisms. P. aeruginosa and Micrococcus sp. showed steady growth at 37°C as well as 50 ⁰C. Micrococcus sp. recorded highest growth; 0.324 nm and 0.312 nm at 37°C and 50°C respectively, after 15 days. Similarly, P. aeruginosa recorded highest growth of 0.40 nm and 0.258 nm for 37°C and 50°C respectively. LDPE degradation increased with increase in time.

Conclusion: This study demonstrates the enormous polyethylene-degrading potentials of P. aeruginosa and Micrococcus sp. isolated from Nsukka, Nigeria.

Aim: The aim of this work was to carry out a screen for methicillin-resistant Staphylococcus aureus (S. aureus) in nasal cavity of patients in the intensive care units of the University Hospital Center (UHC) and the Central Hospital of Yaounde (CHY) in Cameroon.

Study Design: A cross-sectional descriptive study was carried out.

Pace and Duration of the Study: Collection of nasal swab was done in Intensive Care Unit of University Teaching Hospital of Yaounde, and Intensive Care Unit of Central Hospital of Yaounde. Identification and susceptibility test were done in bacteriology laboratory of University Hospital Center, Yaounde between August 2018 and March 2019.

Methods: Nasal swabs were collected from patients by performing rotation in each nose. The identification of bacteria was carried out by observation of mannitol fermentation on Chapman agar, catalase, coagulase and DNAse tests. The susceptibility test was carried out by the method of diffusion of the discs in Mueller-Hinton agar.

Results: A total of 29 S. aureus were identified from 127 patients of which 44.10% were women  and 55.90% were men. The antibiotic resistance profile showed cross-resistance of S. aureus between cefoxitin and others antibiotics with high resistance of amoxicillin, Amoxi / Clavulanic, fusidic acid, gentamycin and tetracycline with rates ranging from 62% to 82%. We detected 58.62% resistant species to cefoxitin and 51.72% were resistant to vancomycin. Statistical analysis found that there was not association between age groups, gender with nasal carriage of S. aureus. However there was an association (P=0,0060) between the hospital attended and the portage of S. aureus.

Conclusion: The prevalence of Methicillin-resistant S. aureus (MRSA) is quite high in intensive care patients. Staphylococcus aureus isolated from carriers also shows resistance to others antibiotics. This can increase the incidence of nosocomial infections. There is a need to implement effective control strategies to prevent infection cross transmission in intensive care Units.

Aim: The aim of the study was to evaluate the potential of Oxidal® to decrease the Ty1 retrotransposition rate in a model system Saccharomyces cerevisiae.

Study Design: Saccharomyces cerevisiae cell suspensions were pre-treated with different concentrations Oxidal® and subsequently treated with 16mM methyl methanesulfonate. (MMS)

Methodology: The potential of various concentrations Oxidal® was evaluated based on “spot” test and Ty1 retro-transposition test.

Results: Data revealed that only 5% Oxidal® possesses some cytotoxic properties. Lack of Ty1 retro-transposition was observed after single treatment with 1, 2.5 and 5% Oxidal® concentrations.

On the other hand, all the tested concentrations showed promising results against the standard carcinogen methyl methane sulfonate. The most pronounced anti-carcinogenic and cytoprotective effects were observed after pre-treatment with 2.5% Oxidal®, which could be attributed to the antioxidant properties of the combination of ingredients; methylene blue, salicylic acid and caffeine. Further studies could reveal the exact mechanism of action of the supplement and the role of the antioxidant potential.

Conclusion: New data is provided concerning the potential of Oxidal® at low concentrations to protect Saccharomyces cerevisiae cells from MMS-induced Ty1 retro-transposition. The cytoprotective properties of the supplement were also obtained. These results could be considered as a basis for further studies revealing the exact mechanisms of cell protection of the Oxidal®. Additionally, our data could also serve as an important step of the in-depth research of a potential antiviral activity.

Aim: Seed treatment with Plant Growth Promoting Bacteria (PGPB) is considered to be safe for seed and environment and ecologically sound. To ensure the benefits of the PGPB, studies were conducted in pearlmillet by treating with liquid microbial cultures for enhancing seed germination and seedling vigour.

Methods: The pearlmillet seeds were infused with different concentrations of liquid microbial cultures and their consortia. Also, the bioinoculant infused seeds were treated with chemicals to assess their effect on the microbial population. 

Results: The pearlmillet seeds soaked in equal volume of Azospirillum or phosphobacteria @ 1:50 dilution or Pink Pigmented Facultative Methylotroph (PPFM) @ 1:100 dilution for 18 h have recorded higher germination and seedling vigour. Pink Pigmented Facultative Methylotroph treated seeds have showed higher germination and seedling vigour amid the microbial cultures. In addition, the bioinoculant treated seed viability and vigour were not affected during three months storage. However, the microbial populations in the seed get declined during storage. The microbial consortia comprising of Azospirillum, phosphobacteria and PPFM did not affect the germination rather seedling vigour. Besides, seeds infused with Azospirillum @ 1:50 dilution and PPFM @1:100 dilution (1:1) for 18 h have recorded higher seedling vigour. In addition, seeds soaked in PPFM @1:100 dilution for 18 h followed by polymer coating @ 5 ml kg^-1 and carbendazim seed treatment @ 2 g kg^-1 of seed had higher germination and seedling vigour. But, the microbial population in the seed was reduced considerably due to the chemical treatment.

Conclusion: The liquid bioinoculants viz., Azospirillum, phosphobacteria and PPFM can be used to pre-inoculate the pearlmillet seeds with required population to be carried over to the field.

Aeromonas spp, ubiquitous in both terrestrial and aquatic environments are becoming renowned as enteric pathogens of serious public health concern as they have a number of virulence and resistant determinants that are linked to both human and aquatic diseases due to consistent and incorrect use of antibiotics in aquaculture. The effect of crude aqueous and ethanol extracts of some medicinal plants on antimicrobial resistant Aeromonas spp. isolated from aquaculture water and fish samples was studied. Two hundred and forty (240) Aeromonas isolates, made up of 168 Aeromonas hydrophila and 72 Aeromonas salmonicida, were recovered from aquaculture water and fish gill samples collected from different commercial fish ponds using selective media. The isolates were assessed for their antibiotic susceptibility against ten (10) conventional antibiotics using the Kirby-Bauer technique. Extracts from three medicinal plants, Vernonia amygdalina, Ocimum gratissimum and Garcinia kola were also analyzed for their antimicrobial effects on the isolates that were resistant to the conventional antibiotics. Aeromonas hydrophila isolates expressed the highest resistant rates of 100%, 78.6% and 70.8% to aztreonam, cefotaxime and neomysin respectively, and the A. salmonicida isolates also had a similar trend of high resistant rates of 100%, 87.5% and 77.8% to aztreonam, neomysin and cefotaxime respectively. Antimicrobial resistant analyses with the plant extracts showed 100% inhibition of the isolates at 100 mg/ml for both aqueous and ethanol extracts. Phytochemical screening identified the presence of certain phytochemicals like alkaloids, saponins, tannins, flavonoids, steroids and glycosides which could have accounted for the antimicrobial effects of the plant extracts under study. It can be inferred then, that extracts from Vernonia amygdalina, Ocimum gratissimum and Garcinia kola can inhibit resistant aquaculture Aeromonas isolates and so can present an alternative source of antimicrobials in the effort to combat the increasing incidence of antimicrobial resistance in aquaculture.