Open Access Minireview Article

Molecular Determinants of Artemisinin Resistance in k13 Gene of Plasmodium falciparum

Zaw Lin, Myo Thura Zaw

Microbiology Research Journal International, Page 1-11
DOI: 10.9734/BMRJ/2015/18776

Artemisinin-based combination therapy (ACT) is the first-line therapy in most malaria endemic countries. An impressive 47% reduction in the global mortality rate between 2000 and 2013 has been achieved by ACT and artemisinin (ART) monotherapy. However, artemisinin resistance (AR) by Plasmodium falciparum (P. falciparum) is now prevalent across south-east Asia (SEA). AR is indicated by delayed parasite clearance of more than 3 days after standard ART treatment and reduced in vitro susceptibility. Recent work has shown association of AR with mutations in the propeller domain of the kelch gene on chromosome 13 (PF3D7_1343700, k13 gene) of P. falciparum. The C580Y mutation of the k13 gene is highly prevalent in Cambodia, Myanmar and eastern and western Thailand, while the F446I mutation is predominant in the China-Myanmar border regions as well as in Myanmar. AR has not reached India and Africa, where non-synonymous mutations not associated with delayed parasite clearance are present. Because the location of Myanmar is central between SEA and Africa, a country-specific strategy for Myanmar Artemisinin Resistance Containment (MARC) is necessary. Moreover, regular periodic tracking of prevalent molecular determinants such as C580Y and F446I mutations will be beneficial.

Open Access Original Research Article

Distribution and Diversity of Indigenous Trichoderma species in Machakos County, Kenya

P. K. Maina, P. M. Wachira, S. A. Okoth, J. W. Kimenju

Microbiology Research Journal International, Page 1-15
DOI: 10.9734/BMRJ/2015/18034

Aim: This study was undertaken in order to determine the effect of land-use intensification on occurrence, distribution, and diversity of Trichoderma fungus.

Study Design: Cross-sectional study.

Place and Distribution of Study: Mycology Laboratory, University of Nairobi between March and September, 2014.

Methodology: Soil samples were collected from both Mwala and Kauti irrigation blocks in Kabaa irrigation scheme of Machakos County, in Kenya under three land use types (LUTs): intensively cultivated farmlands under irrigation, rainfed intensively cultivated farmlands and undisturbed lands. A total of 100 soil samples were obtained from the top 0- 20 cm depth. Trichoderma species were isolated using the dilution plate technique using Trichoderma-selective media (TSM).

Results: A total of 369 Trichoderma isolates were recovered from the three LUTs. These were identified and classified into eleven species. The species identified were: T. harzianum, T. koningii, T. viride, T. asperellum, T. atroviride, T. spirale, T. virens, T. tomentosum, T. brevicompactum, T. crassum and T. hamatum. The most abundant Trichoderma species was T. harzianum with a frequency of isolation of 38.87%, followed by T. koningii and T. viride at 18.03 and 15.49%, respectively. Trichoderma hamatum had the least isolation frequency at 0.41%.  T. harzianum also had the widest distribution. The difference in abundance of Trichoderma in the three LUTs was significant (P=0.05). The undisturbed lands had a higher abundance of Trichoderma compared to the disturbed areas. Mwala irrigation block A had the least abundance while block D which is more recent in cultivation had highest mean abundance of Trichoderma. Difference in Trichoderma species mean richness between LUTs was not significant (P=0.203). Undisturbed lands had the highest richness. Undisturbed lands also had the highest diversity while irrigated lands were the least diverse

Conclusion: Enhanced land-use intensification lowers the abundance and diversity of Trichoderma in the soil.

Open Access Original Research Article

Antibacterial Activity of Organic and Aqueous Extracts of Hopea odorata Roxb. Leaves and their Total Flavonoid Content

Mohammad Shah Hafez Kabir, Muhammad Abdulla Al Noman, Md. Mominur Rahman, Joushan Ara, Mohammed Munawar Hossain, Abul Hasanat, Fahima Zaheed

Microbiology Research Journal International, Page 1-7
DOI: 10.9734/BMRJ/2015/19186

Objective: To examine the antibacterial effects of different extracts of Hopea odorata leaves against bacteria and to determine their total flavonoid content.

Methods: Leaves of Hopea odorata was extracted with pure methanol (MEHO), ethanol (EEHO) and water (AEHO), which are tested for antibacterial activity on three Gram positive and three Gram negative bacteria by disk diffusion method. Total flavonoid content determined based on the method of Wang et al.

Result: Among the all extracts, MEHO exhibited moderate antibacterial activity. It showed zone of inhibition in highest concentration of 2 mg/ml against Gram-positive bacteria Staphylococcus aureus (20.3±0.6 mm), Bacillus subtilis (18.3±0.6 mm), Bacillus megaterium (15.3±0.6 mm) and Gram-negative bacteria Salmonella typhi (18.7±1.2 mm), Escherichia coli (14.3±0.6 mm), Shigella dysenteriae (19±1 mm). The content of flavonoid was present at all extracts, but MEHO (85.98±0.76 mg quercetin/g) contained highest among them.

Conclusion: Our results indicate that extracts have moderate antibacterial activity and flavonoid may one of such phytochemical, which exhibit antibacterial activity.

Open Access Original Research Article

The Diagnosis of Salmonella typhi Co-infection from Blood Samples of Clinically Suspected Typhoid Fever Patients at Some Hospitals in Ondo State, Nigeria

O. E. Ajayi, B. E. Boboye, O. F. Olukunle

Microbiology Research Journal International, Page 1-6
DOI: 10.9734/BMRJ/2015/17316

Background: Blood samples of clinically suspected typhoid fever patients were screened for bacterial and fungal co-infection.

Methodology: The study was conducted in three different hospitals in Ondo State, Nigeria viz; State Specialists’ Hospital, Akure, Don Bosco Clinic, Akure and Federal Medical Centre, Owo, between February and May, 2013. Five hundred and twenty (520) blood samples collected from clinically suspected typhoid fever patients attending three hospitals in Ondo State, Nigeria were screened for the presence of Salmonella typhi, other bacteria and fungi using different growth media.

Results: Sixteen Salmonella typhi isolates (3.08%) were isolated and co-infection with Escherichia coli (31.25%), Shigella flexneri (12.50%), Enterobacter aerogenes (6.25%), Pseudomonas aeruginosa (6.25%),Klebsiella pneumoniae (6.25%), Aspergillus flavus (6.25%), Aspergillus niger (6.25%) and Penicillium italicum(6.25%) was observed. There was co-infection of Escherichia coli with five (5) of the sixteen (16) Salmonella typhi isolates, Shigella flexneri with two (2) isolates while six of the S. typhi isolates had no co-infection. Aspergillus flavus had co-infection with two (2) Salmonella typhi isolates while A. niger and P. italicum had a co-infection with an S. typhi isolate each.

Conclusion: Co-infection of other microorganisms with S. typhi is indicative of immune compromise and other disease conditions in the typhoid fever patients.

Open Access Original Research Article

Bacterial and Drug Susceptibility Profiles of Urinary Tract Infection in Diabetes Mellitus Patients at Mbarara Regional Referral Hospital, Uganda

Lucas Ampaire, Aggrey Butoto, Patrick Orikiriza, Obed Muhwezi

Microbiology Research Journal International, Page 1-5
DOI: 10.9734/BMRJ/2015/17483

Aim: The risk of developing infection in diabetic mellitus patients is known to be higher than in normal individuals. The urinary tract is the most common entry point of infections. Surveillance of urinary tract pathogens and their antibiogram is key to patient management. The main objective of this study is to determine the prevalence of bacterial causative agents of urinary tract infections and their antibiogram in diabetes mellitus patients.

Methods and Materials: A hospital - laboratory based cross-sectional study was conducted from February to April 2014. A total of 105 asymptomatic and symptomatic diabetes patients (55 females and 50 males) that consented were recruited in the study. Mid stream urine samples were obtained for standard culture on CLED agar. Bacterial colonies were subjected to Gram stain and relevant biochemical tests were used for isolate identification and antibiogram determined using Kirby bauer disc diffusion method.  

Results: Significant bacteriuria (≥105 Colonies/mL) was detected in 13.3% (14/105) of the participants. The common causative agents were Escherichia coli (50%), Klebsiella pneumoniae (28.6%), Staphylococcus aureus (14.3%) and unidentified coliform (7.1%). Majority of the isolates showed 92.9% and 85.7% sensitivity to Gentamicin and Ceftriaxone respectively but a relatively low susceptibility of 64.3% to ciprofloxacin and resistance of 78.6%, and 64.3% against co-trimoxazole and Ampicillin respectively. 

Conclusion: Significant bacteriuria was obtained as 13.3% and Escherichia coli (50%) as was the highest uropathogen. Isolates showed high resistance to Co-trimoxazole (78.6%) and ampicillin (64.3%). The isolation of bacterial pathogens that resist the commonly prescribed drugs calls for an early screening of all diabetes mellitus patients with urinary tract infections.

Open Access Original Research Article

Phenotypic and Genotypic Detection of Biofilm Formation in Staphylococcus epidermidis Isolates from Retrieved Orthopaedic Implants and Prostheses

Noha Tharwat Abou El-Khier, Samah Sabry El-Kazzaz, Abd Elrahman Elganainy

Microbiology Research Journal International, Page 1-10
DOI: 10.9734/BMRJ/2015/18650

Background: Most of orthopaedic implant and prosthesis infections are actually biofilm-correlated infections that are highly resistant to antibiotic treatment and to the host immune responses. Staphylococcus epidermidis is considered one of the principal etiologic agents of orthopedic implant infection and prosthetic joint infection (PJI). Moreover, it has strong implant-adhering ability, and its biofilm-forming ability is considered as a serious pathogenic factor. Early detection and management of biofilm-forming S. epidermidis can be one of the essential steps towards the prevention and management of orthopaedic implant and prosthesis infections.

Aim of the Study: To evaluate the biofilm developing ability of the S. epidermidis isolates originated from retrieved orthopedic implants and prostheses with the phenotypic methods of microtiter plate assay (MtP) and Congo red agar (CRA) analysis, as well as detection of icaA and icaD genes by PCR.

Materials and Methods: A total of 39 S. epidermidis isolates obtained from 100 retrieved orthopaedic implants and prostheses were subjected to the biofilm formation and detection with different methods. Isolates were identified by standard microbiological procedures. Qualitative detection of the biofilm formation by the isolates was performed by culturing bacteria on Congo red agar (CRA) plates, while the quantitative detection of biofilm production was done by MtP assay. PCR was performed for the detection of two biofilm-development related genes; icaA and icaD

Results: By CRA method, 17 (43.6%) S. epidermidis isolates were defined as biofilm producers through their black colonies. By MtP assay, 20 isolates (51.3%) were found to be biofilm producers with different grades: 12 (30.8%) strong producers (SP), 5 (12.8%) moderate producers (MP), and 3 (7.7%) weak producers (WP). The icaA and icaD genes were detected concomitantly in 15 (38.5%) isolates. In comparison with the data of ica gene detection, CRA had a sensitivity of 93.3% and specificity of 87.5% while MtP assay represented 100% sensitivity and 79.2% specificity. There was a substantial agreement between MtP assay and the concomitant presence of icaAD genes (kappa= 0.74). It was also noticed that all the SP isolates were positive for ica genes, and perfect agreement (kappa= 0.83) was observed between SP isolates and the concomitant presence of icaAD genes (p<0.0001).

Conclusions: Both genetic and phenotypic analyses are required for optimum evaluation of the biofilm producing ability of clinical S. epidermidis isolates. Moreover, MtP assay is recommended as a general screening method for detection of biofilm from retrieved orthopaedic implants and prostheses.