Open Access Short communication

Identification of Typical Class 1 and Class 2 Integron Gene Cassettes in Clinical Isolates of MDR Shigella flexneri in South Indian Population

M. S. Dhiviya Prabaa, Shalini Anandan, D. R. Naveen Kumar, V. Balaji

Microbiology Research Journal International, Page 1-6
DOI: 10.9734/BMRJ/2015/19498

Aims: Shigellosis is an acute intestinal infection caused by Shigella spp. Treatment with most widely used antimicrobial drugs became limited due to the emergence of multi-drug resistance (MDR). In Shigella spp., antimicrobial resistance is often associated with the presence of transferable genetic elements (integrons and plasmids). Therefore, the study was aimed to identify the pattern of integron distribution in clinical isolates of Shigella spp. in south Indian population.

Place and Duration of Study: Department of Clinical Microbiology, Christian Medical College (CMC), Vellore, between January 2014 and December 2014.

Methodology: A total of 20 out of 67 MDR Shigella isolates were included in the study. All 20 isolates were characterized for the presence of integrons, gene cassettes and other resistant genes by PCR, restriction fragment length polymorphism (RFLP) and sequencing. The integron sequences were deposited in NCBI.

Results: The presence of typical class 1 integron gene cassette dfrA12‐orfF‐aadA2 (KT037078) and class 2 integron gene cassette dfr1-sat2-aadA1 (KT037079) from S. flexneri were first to be reported among Indian population in this study. Also, dfrA1‐sat1‐aadA1 gene cassette of class 2 integron along with dhfr1a, sul2,blaOXAblaTEM, AmpC, blaCTX-M-15 and qnr genes were identified in Shigella spp. in this study.

Conclusion: Association of ESBL, AmpC, blaCTX-M and qnr genes justified the observed phenotypic resistance of the isolates which is of major concern due to the ability of integrons to acquire resistance genes against different antibiotics, since gene cassettes exist to nearly all classes of antibiotics.


Open Access Short communication

Pseudomonas monteilii and Citrobacter murliniae, Biosurfactant-Producing Bacteria Isolated from Nigerian Soil

C. G. Anaukwu, A. I. Ekwealor, C. C. Ezemba, V. N. Anakwenze, U. C. Okafor, E. J. Archibong

Microbiology Research Journal International, Page 1-9
DOI: 10.9734/BMRJ/2015/19742

Aims: To isolate bacterial species with good potentials for biosurfactant production and to determine the tenso-active characteristics of the active producers.

Study Design: Study on biosurfactant-production potential of bacteria in shake flask.

Place and Duration of Study: Department of Applied Microbiology and Brewing, Nnamdi Azikiwe University, Awka, Nigeria, between October 2013 and June 2014.

Methodology: Soils, polluted with spent oil, from different regions of Anambra state, Nigeria, were examined for biosurfactant-producing bacteria. The bacterial isolates were screened for biosurfactant production in mineral salt medium (MSM) and nutrient broth supplemented with olive oil(NB). Biosurfactant production assay fermentation broth, include emulsification index measurement, oil displacement test, drop collapse test and blue agar plate test. The active producers were identified based on 16S rDNA sequencing. 

Results: Out of the twenty-nine bacterial species screened, two of the isolates were recovered as active biosurfactant producers. They were identified as Pseudomonas monteilii AF064458 and Citrobacter murliniae AF025369. The biosurfactant production assay carried out on mineral salt medium and nutrient broth supplemented with olive oil revealed that P. monteilii AF064458 had emulsification index (E24) of 76.67% and 64.85%, oil displacement diameter of 2.1 cm and 1.2 cm respectively. The drop collapse test was positive in both medium and the organism showed a positive blue-agar plate test of 0.8 cm in diameter. With C. murliniae AF025369, an emulsification index (E24) of 66.67% and 63.33%, and an oil displacement diameter of 1.8 cm and 1.6 cm were obtained in MSM and NB respectively. A positive drop collapse test in both medium, and a negative blue-agar plate test were observed. Biosurfactants produced Biosurfactants produced by P. monteilii AF064458 and C. murliniae AF025369 reduced surface tension of water from 72 mN/m to 34 mN/m and 42 mN/m, with critical micelle concentrations (CMC) of 50 mg/L and 60 mg/L respectively.

Conclusion: The findings indicate that Pseudomonas monteilii AF064458 and Citrobacter murliniaeAF025369 are biosurfactant-producing bacteria.


Open Access Original Research Article

Antibacterial Activity of Flavonoids Extracted from Seeds of Pongamia pinnata Linn on Methicillin Resistant Staphylococcus aureus

Mary Shobha Rani Inala, C. D. Dayanand, Nagarjuna Sivaraj, P. M. Beena, A. V. M. Kutty

Microbiology Research Journal International, Page 1-8
DOI: 10.9734/BMRJ/2015/20002

Aims: To assess the antibacterial property of seed crude extracts of Pongamia pinnata Linn and isolated flavonoids component from crude extract against Methicillin resistant Staphylococcus aureus obtained from clinical isolates.

Study Design: Observational study.

Place and Duration of the Study: Department of Allied health sciences, Department of Biochemistry and Department of Microbiology in Sri Devaraj Urs Academy Of Higher Education and  Research ,Tamaka, Kolar, between February 2014 and march 2015

Methodology: Confirmed clinical isolates for MRSA were collected from Microbiology department to test the efficacy of crude extracts of seeds from Pongamia pinnata L. Methanolic crude extract has been preferably used for isolation of flavonoid content using Dimethyl Sulfoxide [DMSO] and methanol as ideal solvents during extraction process by column chromatography technique. Agar well diffusion method was performed to determine the antibacterial activity of crude seed extracts of Pongamia pinnata and isolated flavonoids by using quercitin as positive control for flavonoids. Vancomycin a glycopeptide powder used as gold standard for comparing bactericidal activity of quercitin, flavonoids and crude extracts of P. pinnata on MRSA.

Results: The highest antibacterial activity (75-89%) was observed in crude extract of Pongamia pinnata in comparison to vancomycin considered as cent percent. Extracted flavonoids showed activity (66-92%) with respect to crude extract and (50-84%) with vancomycin and the activity (71-92%) with respect to quercitin when tested with concentration ranging from 25-400 µg/ml.

Conclusion: This study showed that seed extracts of Pongamia Pinnata L and its phytochemical compound flavonoids showed potential antibacterial activity against MRSA using quercitin and vancomycin. 

Open Access Original Research Article

Antidermatophytic Activities of Musa sapientum Methanol Leaf Extract in-vitro

A. O. Ige, O. O. Mebude, B. A. Adeniyi, E. O. Adewoye

Microbiology Research Journal International, Page 1-7
DOI: 10.9734/BMRJ/2015/19261

Aim: The in vitro antidermatophytic activity of methanol leaf extract of Musa sapientum (MSL) against Microsporum canis, Trichophyton tonsurans and Trichophyton rubrum was investigated. 

Methodology: The methanol leaf extract M. sapientum was obtained by cold extraction. The antifungal activity of the extract was assayed using agar well diffusion techniques. The time-kill antibacterial kinetics of the extract was assessed against one strain of M. canis and two strains of T. tonsurans by plate count technique.

Results: The extract had minimum fungicidal concentration (MFC) and minimum inhibitory concentration (MIC) values ranging from 0.0625 mg/ml to 0.5 mg/ml. The least MIC and MFC value was 0.0625 mg/ml against M. canis while T. tonsurans showed the highest MIC and MFC value of 0.5 mg/ml. The extract had no inhibitory or fungicidal effect against T. rubrum. Time-kill kinetic study indicated that the extract exhibited bacteriostatic and bacteriocidal effects against Microsporum canis and Trichophyton tonsurans.

Conclusion: The results obtained suggest that the methanol leaf extract of Musa sapientum possesses antidermatophytic properties.


Open Access Original Research Article

Phytochemical and Antibacterial Investigation of Leaf Extracts of Vernonia amygdalina

Aliyu Ibrahim Yar’adua, Lawal Shuaibu, Abdullahi Nasir

Microbiology Research Journal International, Page 1-6
DOI: 10.9734/BMRJ/2015/19581

Vernonia amygdalina was assessed for phytochemicals. The results showed that the leaf extract of the plant possessed the biologically active substances; cardiac glycosides, alkaloids, saponins and tannins. The presence of these bioactive constituents has been linked to the antimicrobial activity of the plant. The disc diffusion method was used to determine the antimimicrobial activity against Staphylococcus aureusProteus vulgarisEscherichia coliPseudomonas aeroginosaeStreptococcus speciesKlebsialla pneumoniaand Salmonella typhi. Aqueous extract of the leaves showed antimicrobial activity against all the tested bacteria with the exception of Proteus vulgaris in the order of sensitivity as Klebsialla pneumoniaPseudomonas aeroginosae> Staphylococcus aureusSalmonella typhiEscherichia coliStreptococcus species. The leaves of Vernonia amygdalina can be used as a source of oral drugs to fight infections caused by susceptible bacteria.

Open Access Original Research Article

Antibiotics Susceptibility Pattern of Methicillin Resistant Staphylococcus aureus (MRSA) In Enugu State, South-East Region of Nigeria

A. A. Agboke, A. A. Attama

Microbiology Research Journal International, Page 1-7
DOI: 10.9734/BMRJ/2015/18219

Development of antimicrobial resistance by bacteria is now a worldwide health issue, as infection is one of the leading causes of death in the world today. The aim of this study was to evaluate the prevalence and antimicrobials susceptibility pattern of Methicilin-Resistant Staphylococcus aureus in 3 different hospitals in South-East geopolitical region of Nigeria. The identification and confirmation of the S. aureus were done using selective and differential medium (Mannitol salt agar) for S. aureus and by coagulase/staphylase test using Oxoid® reagents kits (DR0595A). The method used for antibiotics susceptibility pattern of the characterised S. aureus isolates was discs diffusion method, as recommended by the Clinical Laboratory Standards Institute (CLSI), discs containing oxacillin (5 µg/disc), vancomycin (30 µg/disc), cephalexin (30 µg/disc), levofloxacin (5 µg/disc), ciprofloxacin (5 µg/disc), tetracycline (30 µg/disc), cotrimoxazole (25 µg/disc), gentamicin (30 µg/disc), clindamycin (2 µg/disc) and rifampicin (5 µg/disc). MRSA confirmation was done using Oxoid® DR0900 penicillin binding protein (pbp2’) latex agglutination test kits. The results showed that out of 218 characterized clinical isolates, 39 of it were confirmed MRSA with varying percentages of resistance to various antibiotics thus: oxacillin (62.07%), vancomycin (60.35%), cephalexin (55.18%), levofloxacin (56.90%), ciprofloxacin (65.52%), tetracycline (68.97%), cotrimoxazole (67.25%), gentamicin (62.07%), clindamycin (63.79%) and rifampicin (62.07%). The S. aureus are more sensitive to Levofloxacin and less sensitive to tetracycline, clindamycin and rimfapicin. Latex agglutination test confirmed 39 strains of the clinical isolates to be MRSA. The results shows open wound as a source with highest prevalence and sputum with lowest prevalence of the MRSA with no significant change (P > 0.05).