Open Access Original Research Article

Post-antibiotic Effects and Post-sub-minimal Inhibitory Concentration Effects of Cetylpyridinium Chloride on Streptococcus gordonii and Streptococcus mutans

So Yeon Lee, Si Young Lee

Journal of Advances in Microbiology, Page 1-5
DOI: 10.9734/JAMB/2018/39739

Background and Objectives: When an antimicrobial agent is removed after the treatment of bacteria for a short period, it takes a long time for the bacteria to return to normal growth, despite the reduction in the antimicrobial agent concentration. This phenomenon is referred to the post-antibiotic effect (PAE). The PAE of cetylpyridinium chloride, which is a common ingredient in oral mouthwash solutions, has not yet been elucidated. We evaluated the post-antibiotic effect (PAE), post-antibiotic sub-MIC effect (PA SME), and sub-MIC effect (SME) for cetylpyridinium chloride in Streptococcus gordonii, which is known to be an early colonizer of the tooth surface, and Streptococcus mutans, a causative agent of dental caries.

Materials and Methods: After cetylpyridinium chloride was applied to bacteria, PAE, PASME and SME were measured to investigate the time to recovery of bacterial growth.

Results: The mean PAE times for S. gordonii and S. mutans were 1 h and 1.07 h, respectively. When the PA SME was compared with the PAE, the PA SME was longer than the PAE in both S. gordonii and S. mutans.

Conclusion: In this study, it was shown that cetylpyridinium chloride can cause a PAE, PA SME and SME; therefore, this pharmacodynamic effect should be expected in the clinical application of cetylpyridinium chloride.

Open Access Original Research Article

Biostimulatory Effect of Cassava Peel Waste on the Indigenous Fungi in Atrazine-impacted Soil

Maduike Eberechukwu Meaky, Stanley Herbert Okechukwu

Journal of Advances in Microbiology, Page 1-11
DOI: 10.9734/JAMB/2018/40088

Biostimulatory Effect of Cassava Peel Waste on the Indigenous Fungi in Atrazine-impacted Soil

The biostimulatory effect of cassava peel waste on the indigenous fungi in atrazine-impacted soil was assessed over a period of seven (7) weeks. The study site was at the Teaching and Research Farm of the institution. The herbicide used in this study was atrazine (Atraforce) while the organic waste used was the cassava peel waste (CPW) of Manihot esculenta. The fungal and physicochemical characteristics of the soil treated with cassava peel waste (CPW), cassava peel waste and atrazine (CPW+ATZ), atrazine alone (ATZ), and the CONTROL (no treatment) were assessed using culture-dependent and standard analytical techniques respectively. The influence of the treatments on soil organic carbon content, total nitrogen content and available phosphorus was investigated and recorded. The study provided adequate evidence that the study site was naturally endowed with requisite fungi (Rhizopus sp., Aspergillus sp., Penicillium sp., Saccharomyces sp., Fusarium sp., Candida sp., and Trichophyton sp.) with potential enzyme repertoire for atrazine degradation. All the seven isolated indigenous fungi except Saccharomyces sp. showed evidence of atrazine degradation potential. The addition of organic amendments improved the physicochemical status of the impacted soil which culminated to significant (P<0.05) increase in soil’s fungal population. For example, CPW+ATZ showed a high mean fungal population (week 2 =30.00x103 CFU/g, week 4 =35.00x103 CFU/g, week 6 =81.00x103 CFU/g) which was significantly higher (at P<0.05) than impacted but unamended soil, ATZ (week 2 =9.50x103 CFU/g, week 4 =12.50x103 CFU/g, week 6=46.50x103 CFU/g). This study has shown that, although fungi are excellent degraders of herbicides in the soil, some amendments may need to be brought in place in order to stimulate them to degrade pollutants. This work also revealed that the organic waste (CPW) used was a potential stimulatory substrate that enhanced the growth of indigenous atrazine-degrading soil fungi; hence can serve as improved method of waste management and potential soil remediation approach.

Open Access Original Research Article

Effect of Sub Minimal Inhibitory Concentration Cetylpyridinium Chloride on Biofilm Formation and Hydropyobicity of Streptococci and Actinomycetes

So Yeon Lee, Si Young Lee

Journal of Advances in Microbiology, Page 1-6
DOI: 10.9734/JAMB/2018/39738

Effect of Sub Minimal Inhibitory Concentration Cetylpyridinium Chloride on Biofilm Formation and Hydropyobicity of Streptococci and Actinomycetes

Background and Objectives: If the antimicrobial agent is not administered continuously, the concentration of the antimicrobial agent necessarily becomes lower than the minimum inhibitory concentration (MIC) and maintains the sub- minimum inhibitory concentration (sub-MIC). There were no studies on the biofilm formation of initial attachment bacteria such as streptococci and actinomyces in cetylpyridinium chloride. In this study, we investigated the effect of cetylpyridinium chloride of sub-MIC on biofilm formation and bacterial cell hydrophobicity using Streptococcus mutans, Streptococcus gordonii, Actinomyces naeslundii and Actinomyces odontolyticus.

Materials and Methods: The degree of biofilm formation was classified into 1-4 according to the degree of adhesion to glass slip. Hydrophobicity was measured to investigate whether differences in biofilm formation were related to differences in bacterial surface hydrophobicity.

Results: When biofilm formation was compared between the control group without cetylpyridinium chloride and the cetylpyridinium chloride sub-MIC, biofilm formation was decreased in the experimental group of S. mutans and A. naeslundii. Cellular hydrophobicity was observed with regard to adhesion and the hydrophobicity of S. mutans and A. naeslundii decreased in the experimental group compared to the control group. However, S. gordonii did not change biofilm formation, but cell hydrophobicity was significantly increased in the experimental group compared to the control group.

Conclusion: When cetylpyridinium chloride was applied to oral bacteria, there was a correlation between biofilm formation and cell hydrophobicity in some bacteria.

Open Access Original Research Article

Prevalence and Factors Associated with Intestinal Candidiasis among HIV Infected Clients Attending Anti-retroviral Therapy Clinic at Kisoro District Hospital, Western Uganda

Sharon Bamanya, Martha Nakaye Mubiru, Bashir Mwambi, Justus Mucungunzi, Dahir Ali Hersi, Christine Atuhairwe, Ivan Mugisha Taremwa

Journal of Advances in Microbiology, Page 1-6
DOI: 10.9734/JAMB/2018/39366

Aim: To determine the prevalence and associated factors of intestinal candidiasis among people living with human immune deficiency virus (PLWHIV) attending Kisoro district Hospital in Western Uganda.

Study Design: This was a cross-sectional study.

Place and Duration of Study: This was conducted in the anti-retroviral therapy (ART) clinic at Kisoro District Hospital (KDH) from May 2016 to June, 2017.

Methodology: The study analyzed fresh stool and ethylene di-amine tetra acetic acid venous blood specimens from 148 HIV seropositive adult participants. Stool samples were microscopically examined as wet preparation and cultured on Sabouraud dextrose agar for isolation and identification of fungal pathogens. Blood was used to assay their CD4+ cell counts. Data were analyzed, and presented as proportions.

Results: The prevalence of intestinal candidiasis was 62.84%. It was highest among participants with CD4+ cells below 250/µL, and more among male participants 75% (36/48).

Open Access Original Research Article

Antibiotic Resistance Profile of Methicillin-Resistant Staphylococcus aureus in Abeokuta, Nigeria

J. A. Osiyemi, O. A. Osinupebi, O. Ejilude, S. O. Makanjuola, N. O. Sunmola, E. O. Osiyemi

Journal of Advances in Microbiology, Page 1-9
DOI: 10.9734/JAMB/2018/39800

Antibiotic Resistance Profile of Methicillin-Resistant Staphylococcus aureus in Abeokuta, Nigeria

A considerable increase in infections caused by methicillin-resistant Staphylococcus aureus (MRSA) has caused a high rate of morbidity among the populace with huge economic loss and severe debility. Therefore, this study examines the pattern of antibiotic resistance of MRSA in clinical samples of patients in Abeokuta, Nigeria using standard recommended procedures. Coagulase test, β-lactamase production, and mannitol fermentation were performed using standard methods. Antibiotic susceptibility was determined using disc diffusion assay and minimum inhibitory concentration by micro-broth dilution method. Vancomycin and Azithromycin resistance profile was performed using colorimetric micro-broth dilution assay.  Multi-resistant antibiotic index of MRSA was also determined.

A total of 338 clinical specimens of Pus, Aspirate, Ear, and Wound swabs were collected from three major health facilities in Abeokuta, Nigeria. Each sample was cultured for bacteria isolates and examined for colonial and cellular morphology while biochemical characterization was performed. Of the 161 Staphylococcus aureus (32.2%) isolated; there was no significant disparity found in relation to the study sites (c2=7.145, p-value = 0.308). 60.2% of the S. aureus analyzed were beta-lactamase producers while only 39.8% were β-lactamase negative.  More than 65% of MRSA showed resistance to Cotrimoxazole, Tetracycline, Cefoxitin, and Erythromycin while 96.9% and 98.5% were resistant to Vancomycin and Azithromycin at MIC>16ug/mL respectively. All the MRSA showed MBC>64ug/ml to both Vancomycin and Azithromycin. Multi-antibiotic resistance index rate of more than 0.2 was shown by 97.0% MRSA to 12 different antibiotics.

The present study indicates a high prevalence rate of MRSA that require empirical and urgent intervention to prevent staphylococcal infection among the hospital patients and its outbreak.