Advanced Journal of Microbiology Research

Advanced Journal of Microbiology Research Vol. 2012

Available online at http://internationalscholarsjournals.org/journal/ajmr

© 2012 International Scholars Journals

Review

Antigenic variation in pathogenic micro-organisms: similarities and differences

Dietmar Steverding

BioMedical Research Centre, School of Medicine, Health Policy and Practice, University of East Anglia, Norwich NR4 7TJ, UK. E-mail: [email protected].

Accepted 13 April, 2012

Abstract

Antigenic variation is a process by which pathogenic micro-organisms escape the immune response of their mammalian hosts. By convergent evolution, protozoal, fungal and bacterial pathogens have developed similar genetic mechanisms for true antigenic variation. In this review article, the biology, the surface antigens and their encoding genes, and the molecular mechanisms of antigenic variation of the protozoa Trypanosoma brucei, Plasmodium falciparum, Babesia bovis, Giardia lamblia, the fungus Pneumocystis carinii, and the bacteria Borrelia hermsii, Anaplasma marginale, Neisseria gonorrhoeae, Mycoplasma bovis and Campylobacter fetus are compared.

Key words: Antigenic variation, pathogens, micro-organisms, molecular mechanisms, immune evasion.

Advanced Journal of Microbiology Research Vol. 2012

Available online at http://internationalscholarsjournals.org/journal/ajmr

© 2012 International Scholars Journals 

Full Length Research Paper

Antimicrobial resistant pattern of Escherichia coli from human clinical samples in Osogbo, south western Nigeria

Olowe O. A¹, Okanlawon B. M², Olowe R. A³ and Olayemi A. B⁴

¹Department of Medical Microbiology and Parasitology, P.M.B.4400, Ladoke Akintola University of Technology, College

of Health Sciences, Osogbo, Osun State, Nigeria.

²Department of Biomedical Sciences, Faculty of Basic Medical Sciences, Ladoke Akintola University of Technology,

College of Health Sciences, Osogbo, Osun State, Nigeria.

³Department of Biology, Federal University of Technology, Akure Ondo State, Nigeria.

⁴Department of Microbiology, Faculty of Sciences, University of Ilorin, Kwara State, Nigeria.

Accepted 17 January, 2012

Abstract

We screened 211 clinical samples of which total of 135 Escherichia coli isolates from different human clinical specimens comprising urine, stool, wound swabs, high vaginal swabs, ear swabs and blood obtained from patients at Ladoke Akintola University Teaching Hospital, Osogbo, Osun State, Nigeria. The isolated E. coli were screened for their antibiograms and plasmid profiles. Seven antimicrobial drugs were used during the study. The prevalence of strains resistance to antimicrobials were; Tetracycline (91.6%), Ampicillin (86.7%), Sulphnamide (77.8%) and Gentamicin and Nalidixic acid which were (39.3%) and (4.1%) respectively. A total of seven antibiotic resistance profiles were obtained with over 64% of the isolates showing multi-drug resistance. Plasmids of three size ranges were detected in all of the isolates. Isolates with high multi-drug resistance profiles were found to possess multiple plasmids with large sizes in the range < 6 – 25 kb. Very large resistance levels > 85% were detected against Tetracycline, Sulphnamide, and Cotrimoxazole while Nalidixic acid showed least resistance of 4.1% among the isolates. Majority of the isolates were positive for betalactamase production when subjected to starch paper method.

Key word: Escherichia coli, betalactamse, antibacteria resistance.

Advanced Journal of Microbiology Research Vol. 2012

Available online at http://internationalscholarsjournals.org/journal/ajmr

© 2012 International Scholars Journals

Full Length Research Paper

Screening and optimization of metal ions to enhance ethanol production using statistical experimental designs

Mary Anupama Palukurty^1*, Naveen Kumar Telgana², Hema Sundar Reddy Bora³, Shiva Naresh Mulampaka⁴

^1,2,3Department of Biotechnology, ANITS, Sangivalasa, Visakhapatnam.

⁴Lecturer, Department of Biotechnology, MSRIT, MSR Nagar, Bangalore – 54.

Accepted 14 March, 2012

Abstract

Ethanol production using jaggery was enhanced in submerged fermentation when the effect of metal inducers was studied using the Plackett-Burman and Box-Behnken designs. Saccharomyces cerevisiae (NCIM 3288) was used as the fermenting organism. The Plackett-Burman design was used to initially screen seven of which the four elements were found to have significant effect on ethanol production. In the next stage, Box-Behnken design was used obtain concentrations of metal ion’s that may be supplemented to get maximum ethanol in during production process. It was observed that ethanol yield has increased to 94.8 from 75.4g/l when supplemented with the critical concentrations of salts provided by the model. These were as follows (g/l): FeSO4. 7H 2O 0.0036, MgSO4.7H2O 0.0033, MnCl2. 4H 2O 0.0017 and ZnSO4.7H 2O 0.0026, in the presence of 220 g/l of jaggery supplemented with (NH4)2SO4 2.612 g/l and KH2PO4 3.407 g/l, while the predicted concentration of ethanol as per the model is 95.35 g/l.

Key words: Jaggery, ethanol, Plackett-Burman design, Box-Behnken design, metal inducers.

Advanced Journal of Microbiology Research Vol. 2012

Available online at http://internationalscholarsjournals.org/journal/ajmr

© 2012 International Scholars Journals

Full Length Research Paper

Antioxidant status of Nigerian children with Plasmodium falciparum malaria

Nmorsi O.P.G.¹*, Ukwandu N.C.D.² and Egwunyenga A.O.³

¹Tropical Disease Research Unit, Department of Zoology, Ambrose Alli University, Ekpoma, Nigeria.

²Department of Medical Microbiology, Ambrose Alli University, Ekpoma, Nigeria.

³Department of Zoology, Delta State University, Abraka, Nigeria.

Accepted 17 April, 2012

Abstract

We evaluated the antioxidant status of 148 Nigerian children with Plasmodium falciparum malaria. The mean malarial parasitaemia was 4701.05 ± 2160.53/µL. The mean antioxidant concentrations of the infected children were determined for vitamin A (12.16 ± 1 - 16 µg/dL), vitamin C (0.43 ± 0.03 mg/dL), 5 carotenes (40.96 ± 5.38 µg/dL), and vitamin E (0.45 ± 0.03 mg/dL) . The control subjects had higher mean concentrations of vitamin A (72.12 ± 3.12 µg/dL), and of the 5 carotenes (132.63 ± 22.45 µg/dL), and these differences were statistically significant (X² = 42.86, P > 0.05 and X² = 50.64, P > 0.05, respectively). The mean concentrations of vitamin C (1.22 ± 0.31 mg/dL) and vitamin E (1.03 ± 0.48 mg/dL) in the control children were not statistically significant when compared with their infected children (X² = 0.34, P < 0.05) and (X² = 0.66, P < 0.05), respectively. The relationship between malarial parasitaemia and the concentrations of vitamin E and the 5 carotenes were positively correlated (r = 0.83 and r = 0.99, respectively) . The levels of plasma vitamin A and vitamin C were negatively correlated with the malarial parasitaemia (r = -0.98, and r = -0.96, respectively). Children within their first 5 years of age had higher malarial parasitaemia (7628.42 ± 3151.42/µL) than those > 6 years (1176.58 ± 956/µL). The children between 1 - 5 years old had lower concentrations of vitamin A (8.89 ± 3.74 µg/dL) and vitamin C (0.28 ± 0.21 µg/dL), while the concentration of the 5 carotenes (44.54 µg/dL) and of vitamin E (0.50 ± 0.16 µg/dL) was higher in these children. In conclusion, the depressed levels of plasma antioxidants in the P. falciparum-infected children suggested lowered immunity of the children, which may contribute to the morbidity and mortality of malaria in our locality.

Key words: Vitamin A, vitamin C, vitamin E, antioxidants, Children, Plasmodium falciparum, Nigeria.

Advanced Journal of Microbiology Research Vol. 2012

Available online at http://internationalscholarsjournals.org/journal/ajmr

© 2012 International Scholars Journals

Full Length Research Paper

Retrospective study on the antibiotic resistant pattern of Salmonella typhi from some clinical samples

Doughari, J. H.¹*, Elmahmood, A. M¹. and Nggada, H. P.²

¹Department of Microbiology, School of Pure and Applied Sciences, Federal University of Technology; PMB 2076 Yola.

 ²Department of Medical Microbiology and Parasitology, University or Port Harcourt Teaching Hospital, PMB 6173 – Port Harcourt, Rivers State, Nigeria.

Accepted 24 July, 2012

Abstract

Due to reported cases of antimicrobial resistance by many pathogenic bacteria against many antibiotics worldwide, and the sparse nature of antimicrobial resistance data, a retrospective study was carried out on 744 isolates of Salmonella typhi obtained from 974 samples from four different hospitals in Yola, Adamawa State, Nigeria between 2001-2004 to determine the resistance pattern of S. typhi to the most commonly used antibiotics cotrimoxazole, ciprofloxacin, chloramphenicol and ampicillin. High rates of resistance was found in most of the isolates studied. Resistance rates were 92.3, 88.8, 79.6, 53.5 and 20% to amoxicillin, ampicillin, chloramphenicol, cotrimoxazole and ciprofloxacin, respectively. The high percentage resistance to the antibiotics studied could be attributed to their prevailing usage and abuse in the area under study. The implication of the high percentage resistance recorded for the antibiotics is that only ciprofloxacin will effectively treat S. typhi infections. These results call for nationwide surveillance programme to monitor microbial trends and antimicrobial resistance patterns in Nigeria.

Key words: Antibiotics, resistance, surveillance, Nigeria, Salmonella typhi.

Advanced Journal of Microbiology Research Vol. 2012

Available online at http://internationalscholarsjournals.org/journal/ajmr

© 2012 International Scholars Journals

Full Length Research Paper

Dielectric measurement of the resistance of Trichosporon cutaneum against toxic chemicals

Filadia P. Tileva¹, Lyubov K. Yotova¹ and Gerard H. Markx²*

¹Department of Biotechnology, University of Chemical Technology and Metallurgy, BU-1756 Sofia, Bulgaria.

²School of Engineering and Physical Sciences, Heriot-Watt University, Riccarton, Edinburgh, EH14 4AS, UK.

Accepted 28 June, 2012

Abstract

Conditioning of cultures involves growing cells in the presence of increasing amounts of a toxic chemical. In order to investigate how conditioning affects a culture’s ability to resist new challenges, the resistance of Trichosporon cutaneum to various toxic chemicals, before and after conditioning to growth on phenol, was investigated by measuring the capacitance of cell suspensions at 0.4 MHz following a toxic challenge. The results show that cells grown on phenol are more resistant to the influence of polar aromatic toxic chemicals such as phenol (log Pow = 1.48) and benzylalcohol (log Pow = 1.1), but less resistant against less polar non-aromatic compounds such as n-octanol (log Pow = 2.9). In reverse, cells grown on glucose were found to be more resistant against n-octanol, but less so against phenol and benzylalcohol. The results indicate that cells, adapted to be more resistant to one type of substance, may become more susceptible to other compounds.

Key words: conditioning, adaptation, membrane, Trichosporon cutaneum, capacitance.