Iranian Journal of Microbiology
Volume:1 Issue: 2, Jun 2009

There are limitations in time and technique for isolation of Brucella from patients. We developed a new Brucella culture medium and evaluated its efficiency compared to BACTEC blood culture system and serology. A bi-phasic medium containing Urea agar and Brain Heart Infusion was formulated. Appearance of clear red color in liquid phase was the basis of positivity for Brucella. The new medium which is designated as TUMS medium (TUMS refers to Tehran University of Medical Sciences) and BACTEC blood culture vials were inoculated with different concentrations of 20 Brucella strains. The blood samples from 58 suspected patients were tested by both media and serology (Wright and Coombs). Any growth was sub-cultured and suspected colonies were identified by standard methods. The TUMS medium detected more positive samples (100%) than BACTEC (85%) when the organism was suspended at lower concentration (10 CFU). Of 58 blood cultures, 47 (81%) samples tested on TUMS medium (incubation period =4.2 days) and 39 (67.2 %) samples tested on BACTEC (incubation period =3.3 days) were found positive. The TUMS medium was superior to others in detecting the organism from patients with clinical signs or who took medications for >1year. The TUMS medium is easy to prepare and use in endemic areas where resources are limited.

Bordetella species colonize the respiratory tract of mammals and thereby cause the whooping cough. Most of the species produce adenylate cyclase - a toxin (hemolysin) responsible for increasing intracellular cyclic AMP (cAMP) levels in mammalian neutrophils and macrophages and as a consequence their phagocytic function get impaired. This study was carried out to isolate species of Bordetella and to study the hemolytic activity of each species on RBCs of sheep, human and poultry at varied culture conditions by altering the temperature, pH and cell age. Three pathogenic Bordetella species were isolated from fifty suspected whooping cough patients on Bordet-Gengou agar and identified by their biochemical profiles. The hemolytic activity of B. pertussis, B. parapertussis and B. bronchiseptica was investigated in terms of cell bound and cell free hemolysin on human, poultry and sheep RBCs at variable pH, temperature and cell age in Stainer Scholt broth. The hemolysin activity was also determined qualitatively on blood agar containing different blood samples. All the species revealed optimum hemolytic activity in pH range 7.5-8.0 (in slight alkaline condition), temperature 37°C and cell age up to 20-24 hrs. The cell bound hemolytic activity was found to be maximum than cell free activity and varied with blood samples of different species. B. pertussis showed maximum hemolytic activity on human red blood cells followed by poultry and sheep RBCs. B. parapertussis and B. bronchiseptica showed maximum hemolytic activity on sheep and poultry RBCs respectively. The findings of our study revealed that different determinants are involved in host interactions and virulence of Bordetella species.

Leptospirosis is considered to be the most widespread zoonotic disease in the world and can infect a wide range of animals. Although the prevalence of clinical leptospirosis in cats is low, they are probably exposed to leptospires excreted by wild life, rodents etc. This study was performed to determine the serologic reaction of cats to leptospires and their importance in transmission of this zoonotic disease in Tehran. Serum samples were collected from 111 stray and household cats and were tested for the presence of antibodies against leptospirosis by Microscopic Agglutination Test (MAT). Thirty (27 percent-19 stray and 11 household) of the 111 cats reacted with the various leptospiral serotypes. The dilutions of sera with positive results ranged from 1/100 to 1/600. Serologic reaction was more prevalent in domestic cats (p=0.0067). In stray cats, 18 cases were positive against L. interrogans serovar Canicola (94.7 percent) and one (5.3 percent) against L. interrogans serovar Pomona. In the household group, 6 cats (54.5 percent) reacted with L. borgpetersenii serovar Hardjo, 3 cats (27.3 percent) with L. interrogans serovar Icterohaemorrhagiae, one (9 percent) with L. interrogans serovar Grippotyphosa and one with L. interrogans serovar Canicola. Cats can be exposed to leptospires and in optimal conditions they can infect the environment or transmit the disease to contact people.

Anaplasma phagocytophilum is a zoonotic, tick borne rickettsial pathogen. A. phagocytophilum has been detected in North America, Europe, Africa and Asia by molecular methods. In Iran we have little information about the distribution of this agent in human and animals. From March 2007 to July 2007, one hundred and fifty blood samples and corresponding blood smears of cattle without any signs of disease were prepared from a region in Isfahan, Iran with previous history of tick borne disease outbreak.The blood smears were first stained with Giemsa and analyzed for the presence of A. phagocytophilum in the neutrophils. The extracted DNA from blood cells were analyzed by A. phagocytophilum specific nested PCR using primers derived from the 16S rRNA gene. All blood smears were negative for A. phagocytophilum like structures by Giemsa staining, but 2 out of 150 blood samples (1.33%) were positive for A. phagocytophilum specific nested PCR using specific primers derived from 16S rRNA gene. This study is the first detection of A. phagocytophilum in carrier cattle in Iran. The present study showed that A. Phagocytophilum is detectable in cattle without any sign of infection but maintained a persistant sub-clinical state in the cattle reservoir, which can be inferred as possible risk for management of public health.

The Artemisia genus of Asteraceae family is represented by 34 species in Iran. Artemisia sieberi grows wild in different regions of Iran and grows in desert and semi- desert climate and has forage value for animals and also medicinal properties for humans. In this study we examined the antimicrobial effects of A. sieberi. The antimicrobial activity of A. sieberi essential oil was evaluated against different microorganisms including Gram positive bacteria, Gram negative bacteria, yeast and fungi by disc diffusion method and micro broth dilution assay. The oil with main components of α- thujone, β- thujone and camphor showed antimicrobial activity against dif ferent microorganisms with varying types of pathogens. Gram positive bacteria and fungi were more sensitive than Gram negative ones. Among Gram positive bacilli, Listeria monocytogenes and Bacillus cereus and among Gram positive cocci, Streptococcus mutans were more sensitive than others.The antimicrobial properties of this oil showed that the A. sieberi essential oil has good potential use in the food and cosmetic industry.

Research on Xylanase has markedly increased due to its potential applications in pulping and bleaching processes using cellulose free preparations, textile processes, the enzymatic saccharification of lignocellulosic materials and waste treatment. The present study was aimed at isolation and characterization of xylan degrading strain of Bacillus cereus from soil for production of xylanase. Twelve isolates were obtained from soil samples of different areas in the Rajshahi University campus and studied for detection of xylanase activity. One of the strains was identified as Bacillus cereus on the basis of the nucleotide sequence of the 16S rRNA gene which produces xylanase extracellularly. We purified xylanase to homogeneity by a combination of ammonium-sulphate precipitation, DEAE-sepharose, Phenyl-5PW and Hydroxyapatite column chromatography using culture supernatant. The SDS-PAGE gave a single band at 32 kDa. The optimum temperature and pH of the purified enzyme was 40oC and 6.0, respectively. The xylanase hydrolyzed oat spelt xylan, birch wood xylan and beech wood xylan efficiently but showed no activity towards cellulose, CM-cellulose and Avicell pH 101. Thus it was a true and neutral xylanase. The isolation of xylanase from Bacillus cereus is rare.

Biosurfactants are surface active agents with broad range commercial applications in various industries and have considerable advantages over their chemical counterparts. In this study, bacteria were isolated from contaminated and uncontaminated soil and selected during preliminary screening using hemolytic activity, oil spreading and oil collapsed techniques. Isolates with at least more than one positive response to these three methods were subjected to complementary screening by measuring surface tension reduction as well as emulsification capacity. The criteria for selection of potent isolates were surface tension reduction below 40 mN/m and emulsification capacity of more than fifty percent. Using these stepwise screening procedures, two biosurfactant/bioemulsifier producing isolates have been successfully selected that were able to reduce surface tension effectively and one of which formed a stable emulsion. Phylogenic relationships of the two potential candidates were determined comparing the 16Sr DNA gene sequences, revealing them as two isolates of Bacillus subtilis and Bacillus cereus that can be used in pilot scale for industrial production of new biosurfactant/bioemulsifier.