Advanced Journal of Microbiology Research

Advanced Journal of Microbiology Research Vol. 2016

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

© 2015 International Scholars Journals

Full Length Research Paper

Investigation of different infectious pathways used by Streptococcus suis type 2 and other bacteria in mice

Xingjian Cao, Zhaoming cao, Guohua Tao, Wei Xie, Xiang Chen and Shuo Wang

Center of Clinical Laboratory Medicine, the Second Affiliated Hospital of Nantong University, Nantong 226001, China.

Accepted 19 March, 2015

Abstract

The purpose of this study was to investigate the infectious pathways used by Streptococcus suis type 2 and enterohemorrhagic Escherchia coli O26 (EHEC O26) in mice. Six-week mice were intraperitoneally injected with mitomycin (0.2 mg/mouse) to decrease the protective immunity. The mice were then challenged with S. suis type 2 and EHEC O26 strains through wounded skin, stomach lavaging and intraperitoneal injection. Enterococcus faecalis ATCC 29212 and E. coli ATCC25922 were used as negative controls. Clinical and microbiological examinations were performed for all the infected mice routinely. The mortality rate of the mice infected with S. suis type 2 strain through wounded skin was 60% within 2 - 5 days. The mortality rate of the mice infected with S. suis type 2 strain through stomach lavaging was 60% within 7 - 10 days. S. suis type 2 can be isolated from the puncturing fluid of heart in the dead mice. Mortality was not observed in mice infected by S. suis type 2 and E. faecalis ATCC 29212 strains through intraperitoneal injection. However, intraperitoneal injection with EHEC O26 and E. coli ATCC25922 caused death of mice within 10 h. We demonstrated an important pathway used by S. suis type 2 strain in mouse infection model. Intraperitoneal injection with gram negative bacteria (E. coli ATCC25922 and EHEC O26) caused non-specific death in mice. These results provided fundamental bases for investigating the pathogenesis of S. suis type 2, designing vaccine and evaluating the efficiency of antimicrobial drugs.

Key words: Streptococcus suis type 2, enterohemorrhagic Escherchia coil O26, model, mouse.

Advanced Journal of Microbiology Research Vol. 2016

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

© 2016 International Scholars Journals

Full Length Research Paper

Antibacterial activity and mechanism of recombinant human-defensin 5 against clinical antibiotic-resistant strains

A. P. Wang, Y. P. Su, S. Wang, M. Q. Shen, F. Chen, M. Chen, X. Z. Ran, T. M. Chen and J. P. Wang*

State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Combined Injury of PLA, Third Military Medical University, Chongqing, 400038, People’s Republic of China.

Accepted 1 March, 2016

Abstract

The increasing clinical bacterial strains resistant to conventional antibiotics have being a great challenge to the public’s health. As a novel kind of antimicrobial agent, defensins are undoubtedly worthy of exploitation for the treatment of antibiotic-resistant bacteria. To evaluate the antibacterial potency of recombinant mature human -defensin 5 (rmHD5) against clinical pathogenic strains, we examined its antibacterial kinetics and bactericidal efficacy on forty-nine bacterial strains (belonging to eleven species) with different antibiotic-resistant phenotypes, isolated from digestive and urogenital tracts of the inpatient. Meanwhile, the action mechanism of rmHD5 was analyzed by transmission electron microscopy observation and membrane permeability detection. The peptide of rmHD5 was found to possess high potency against all the tested isolates at concentrations of 6 - 12 g/ml for gram-negative (G-) bacteria and 28 - 32 g/ml for gram-positive (G+) bacteria. G- bacteria were more susceptible to the peptide than G+ bacteria. Abnormal morphological changes and increased permeabilization of the cytomembrane were observed in both G - bacteria and G+ bacteria treated with rmHD5. The antibacterial activity of rmHD5 may be tightly associated with the biomembrane permeabilization. Recombinant mHD5 is a promising candidate to be developed into therapeutic agents for bacterial infections.

Key words: Antibacterial activity, mechanism, antibiotics resistant strain, human alpha defensin 5.

Advanced Journal of Microbiology Research Vol. 2016

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

© 2016 International Scholars Journals

Full Length Research Paper

Efficiency of filtration technique for isolation of leptospires from surface waters: Role of different membranes with different pore size and materials

Hami Kaboosi¹*, Mohammad Reza Razavi^1,2 and Ashraf al Sadat Noohi¹

¹Department of Microbiology, Science and Research branch, Islamic Azad University, Tehran, Iran.

²Department of Parasitology, Pasteur Institute of Iran, No. 69, Pasteur Ave., Tehran, Iran.

Accepted 25 January, 2016

Abstract

The objective of this research focused on evaluation of membrane filters application for isolation of Leptospira from surface water samples. The filter materials evaluated included nitrocellulose (0.22 and 0.45 µm pore diameters), polyvinylidene fluoride (Durapore 0.22 and 0.40 m pore diameters), nylon mesh (37 m), and glass fiber (1.0 µm). Millipore polyvinylidene fluoride filter (0.22 m) was examined by scanning electron microscopy to verify that leptospires were present following filtration. Our results suggest for isolate nearly 100% of Leptospira from water samples, the optimal pore diameter should be less than 0.45 µm (a standard pore size used to detect indicator microorganisms in 100 ml of water). Although filtration method can be used to isolation leptospires from surface water samples, it is unclear whether this is a useful method for detection of all leptospires exist within surface water samples. Accordingly, a large proportion of leptospires can be retained by membrane filter with a pore diameter commonly used to isolate leptospires from surface water samples (0.45 µm pore size).

Key words: Leptospira, filtration technique, leptospirosis.

Advanced Journal of Microbiology Research Vol. 2016

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

© 2016 International Scholars Journals

Full Length Research Paper

The validity of the diagnostic methods in predicting pulmonary tuberculosis

Sulhattin Arslan¹*, Levent Özdemir², Yeltekin Demirel³ and Ibrahim Akkurt¹

¹Department of Chest Diseases, Faculty of Medicine, Cumhuriyet University, 58140 Sivas, Turkey.

²Department of Public Health, Faculty of Medicine, Cumhuriyet University, 58140 Sivas, Turkey.

³Department of Family Doctor, Faculty of Medicine, Cumhuriyet University, 58140 Sivas, Turkey.

Accepted 12 March, 2015

Abstract

In our study, we aimed to determine the validity of diagnostic methods for tuberculosis. Eighty-one people suspected to have tuberculosis were included in the study. The validity of the applied methods for the diagnosis of tuberculosis tuberculin skin test (TST), sputum smear, and used in diagnostic chest X-ray findings (CXR), clinical features and history were evaluated as culture was considered the reference test. Included in the study of 81 people (54 males 27 females) mean age was determined as 45.04 ± 18.69. The most sensitive diagnostic methods were detected as clinical and sputum smears (89 and 86%). The sensitivity of PPD and Radiology have been identified as 0.74 and 0.73 respectively. Diagnostic method with the highest specificity value was found to be radiology. The positive predictive values of PPD, radiology, clinical and sputum smear were identified as 98, 94, 96 and 92%, respectively. PPD had the lowest negative predictive value with 26%. In our study, the validity of the diagnostic methods for the tuberculosis are compatible with the literature. These methods in the diagnosis of tuberculosis are still valid. We think our study may add to the current data in the literature about the topic.

Key words: Validity, specificity, sensitivity, PPD, TST, sputum smear, culture, tuberculosis, clinical features.

Advanced Journal of Microbiology Research Vol. 2016

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

© 2016 International Scholars Journals

Full Length Research Paper

Phenotypic and molecular characterization of SHV, TEM, CTX- M and extended-spectrum  -lactamase produced by Escherichia coli, Acinobacter baumannii and Klebsiella isolates in a Turkish hospital

Elif Burcu Bali¹, Leyla Açık¹* and Nedim Sultan²

¹Department of Biology, Science and Arts Faculty, Gazi University, Ankara, 06500, Turkey.

²Department of Microbiology, Faculty of Medicine, Gazi University, Ankara, 06500, Turkey.

Accepted 2 April, 2015

Abstract

A total of 94 clinical isolates were collected from Gazi University Hospital, Turkey. Presence of ESBL positivity was detected using the double disk synergy test (DDST). ESBL isolates were further typed for the bla_TEM, bla_SHV, bla_CTX-M and bla_OXA using designed primers. ESBLs were found in 65 (69.14%) isolates using DDST. Plasmid DNAs of potentially ESBL positive strains were isolated. About 7.69% of the ESBL positive isolates did not harbour plasmid DNA. According to the PCR technique, only 2 additional isolates were found to be ESBL producers. blaTEM was the commonest genotype (73.43%), followed by blaSHV (21.87%) and blaCTX-M (17.18%), either alone or in combination. ESBL positive strains of Klebsiella pneumoniae, Escherichia coli, Acinetobacter baumannii and Pseudomonas aeruginosa are increasingly found in hospital isolates. Because these strains become resistant to available antibiotics and they can pass the gene to other clinical strains, the quick detection of these strains in clinical laboratories is very important.

Key words: ESBL, double disk synergy test, plasmid, PCR.

Advanced Journal of Microbiology Research Vol. 2016

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

© 2015 International Scholars Journals

Full Length Research Paper

ISSR for comparison of cross-inoculation potential of Colletotrichum capsici causing chilli anthracnose

Kanchalika Ratanacherdchai^1*, Hong-Kai Wang², Fu-Cheng Lin² and Kasem Soytong³

¹International College, King Mongkut’s Institute of Technology Ladkrabang, Ladkrabang, Bangkok 10520, Thailand.

²Biotechnology Institute, School of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310029, P. R. China.

³Department of Plant Pest Management Technology, Faculty of Agricultural Technology, King Mongkut’s Institute of Technology Ladkrabang, Ladkrabang, Bangkok 10520, Thailand.

Accepted 9 November, 2015

Abstract

Thirty-four isolates of Colletotrichum spp. including 2 species, C. gloeosporioides and C. capsici, from anthracnose on Bell pepper, Long cayenne pepper and Bird’s eye chilli were isolated and their pathogenicity was proven via fruit inoculation. Pathogenicity tests divided pathogenic potential into low, medium and high virulence groups. It is clearly revealed that C. capsici from the three tested hosts expressed the highest virulent isolates. Cross-inoculation of three high virulent isolates of C. capsici in accordance with three chilli varieties showed that all isolates could produce anthracnose symptom in the same lesions. All tested isolates developed lesions after co-inoculation of all hosts. Inter simple sequence repeat (ISSR) analysis indicated that there are two distinct groups of C. gloeosporioides and C. capsici. Furthermore, genetic diversity was correlated with geographic distribution, while there was no clear relationship between genetic diversity and pathogenic variability. But it is clearly demonstrated that whereas C. gloeosporioides appears in the same geographic area as C. capsici, it causes lower disease incidence.

Key words: Anthracnose, chilli, Colletotrichum capsici, cross-inoculation.