Iranian Journal of Microbiology
Volume:5 Issue: 1, Mar 2013

For the whole 20th century, bovine tuberculosis (BTB) challenged the international community efforts to control this zoonotic disease. Asia and Africa accommodate the largest BTB-infected zebu cattle in the world. Similar to other few Asian nations, Iran has been actively running its BTB-control plan for the last four decades. BTB however, is still a number-one health concern for Iranian veterinary practitioners and also farmers across the country. Why is that? Here we have addressed this question in the light of most recent epidemiological data as well as microbiology and molecular biology observations.

Because of the difficulty in the diagnosis of brucellosis, particularly in endemic areas, the use of new and feasible diagnostic tests seem to be of great importance for resolving the diagnostic obstacles. We evaluated the usefulness of a new serological test based on an immunocapture-agglutination technique in comparison with ELISA test for serological diagnosis of brucellosis. A total of 11 patients with brucellosis, who had positive blood cultures for Brucella species, and 47 suspected patients were included in this study. Serum samples collected from these patients were tested by brucellacapt and ELISA and the results were, consequently, compared. In patients with positive blood culture, all the samples gave positive results with brucellacapt test while IgM ELISA, IgG ELISA and (IgG + IgM) ELISA tests were positive in 8, 9 and 11 patients, respectively. Out of the 46 suspected patients, (IgG + IgM) ELISA, Brucellacapt, IgG ELISA and IgM ELISA were positive in 37, 15, 34 and 37 patients, respectively.The best cut-off point of ELISA-IgG was 10.78 IU/ml which produced the maximal sensitivity and specificity for the diagnosis of human brucellosis. Both the (IgG + IgM) ELISA and Brucellacapt tests demonstrate a high specificity in this study. According to the results of the current study, it is found that both tests are valuable tools for diagnosis of brucellosis in Iran as an endemic area of brucellosis. It is strongly suggested that a combination of both tests to be used for the diagnosis of brucellosis.

Brucella melitensis infection is still a major health problem for human and cattle in developing countries and the Middle East. In this study, in order to screen immunogenic candidate antigens for the development of a Brucella subunit vaccine, a cytoplasmic protein (DnaK) and an outer membrane protein (Omp31) of B. melitensis were cloned, expressed in E.coli BL21 and then purified using Ni-NTA agarose. Immunized serum was prepared from a rabbit inoculated with attenuated B. melitensis.Results and It was proved that immunized serum contains antibodies against recombinant Omp31 (rOmp31) and DnaK (rDnaK) by Western blot and ELISA assays. The results may suggest the importance of these proteins as subunit vaccines against B. melitensis as well as targets for immunotherapy.

Brucellosis is a zoonotic disease of worldwide distribution and has great economic importance. Despite its control in many countries, it remains endemic in Iran. Brucellosis was investigated in many high risk occupational groups; however, few studies on the prevalence of brucellosis among blood donors are available. To determine the seroprevalence of brucellosis antibodies in blood donors, a serological study was carried out in central province of Iran. A total of 897 healthy blood donors with mean age 37.23 ± 10.9 years were enrolled in the study. Laboratory tests including Standard Tube Agglutination Test (STA) and 2-mercaptoethanol (2ME) agglutination were checked in all samples. STA dilution ≥ 1:80, and in the presence of 2-mercaptoethanol (2ME) agglutination ≥ 20 was considered positive. Out of 897 cases, 11.9% were inhabitants of rural areas. 41.5% had history of consumption of unpasteurized dairy products and 9.3% had history of contact with domestic animals. A very low level of Brucella agglutinins was present in 3(0.33%) of the samples and only one sample (0.11%) was found to be truly positive for Brucella agglutinins. 2ME was negative in all samples. None of these 4 subjects showed signs and symptoms of brucellosis in 6 months follow-up. On the basis of our data, brucellosis has no epidemiological and clinical importance in our blood donors; therefore, it is not recommended to perform screening tests such as, STA and 2ME to identify brucellosis antibodies in the sera of blood donors.

Alterations in CXCL10 (a Th1 chemokine) expression have been associated with various diseases. The aim of this study was to evaluate the serum CXCL10 levels in H. pylori-infected patients with peptic ulcer (PU) and to determine its association with bacterial virulence factor cytotoxin-associated gene A (CagA). Serum samples from 90 H. pylori infected patients (70 were anti-CagA+, 20 were anti-CagA-), 65 asymptomatic (AS) carriers (40 were anti-CagA+, 25 were anti-CagA-) and 30 healthy H. pylori-negative subjects (as a control) were tested for the concentrations of CXCL10 by using ELISA method. The mean serum levels of CXCL10 in PU patients (96.64 ± 20.85 Pg/mL) was significantly lower than those observed in AS subjects (162.16 ± 53.31 Pg/mL, P < 0.01) and control group (193.93 ± 42.14 Pg/mL, P < 0.02). In the PU group, the levels of CXCL10 in anti-CagA+ subjects was significantly higher in comparison to anti-CagA- patients (P<0.04). These results showed that the mean concentrations of CXCL10 in H. pylori-infected-PU patients was lower than AS carriers and control group. In the PU group, the serum levels of CXCL10 were affected by bacterial factor CagA.

Antibiotic resistance of Pseudomonas aeruginosa remain the major problem in burned patients. In this study, we aimed to determine the prevalence and antibiotic resistance pattern of P. aeruginosa isolated from patient with burn wound infections in a new Burn Centre, Guilan, Iran. Sample collected from 182 Patients with burn wounds infection and P.aeruginosa were identified by standard bacteriological methods. The drug susceptibility tests were done for all isolates by agar disk diffusion method for eleven antimicrobial agents. 86 (47%), P.aeruginosa strains were isolated from the 182 patients hospitalized in burns center. Rate of antibiotic resistance were to cloxacillin (91.8%), cotrimoxazole (86%), cephazolin(83.7%), Carbenicillin(74.4%), piperacillin (69.9%) ceftazidime(68.8%), ciprofloxacin (66.3%), tobramycin(58.2%), amikacin (48.8%) gentamicin(37.2%) respectively. The most effective antibiotic was imipenem (23.3%). A total 17 (19.7%) isolates were resistant to all class tested antibiotic and 39 (42.3%) of strains were isolated as multidrug-resistant. P. aeruginosa isolated from burn wound were resistance to more tested antibiotics, therefore optimization of antimicrobial use and control of infection recommended for preventing the increase in resistant organisms.

Pathogenic strains of Escherichia coli are a common cause of acute infectious diarrhea. The aim of this study was to investigate the frequency, virulence markers and antibiotic resistance patterns of diarrheagenic E. coli (DEC) isolated from adolescents and adults in Hamadan, west of Iran. A total of 187 stool samples were collected from adults with acute diarrhea. Stool culture was performed by conventional methods for enteropathogenic bacteria. Virulence factor genes for DEC were detected by polymerase chain reaction. Antimicrobial susceptibility was tested using the disk diffusion method. Among the 187 patients, 40 (21.4%) were positive for DEC. The most frequently identified DEC was enteropathogenic E. coli (47.5%), followed by enteroaggregative (20%), enterotoxigenic (17.5%) and shiga-toxin producing E. coli (15%). No isolates of enteroinvasive E. coli were detected. All STEC strains were stx+ / eaeA-. Out of the seven ETEC strains, five (71.4%) produced ST, one (14.3%) produced only LT and one (14.3%) of the isolates produced both ST and LT encoded by est and elt genes, respectively. Among the 40 DEC strains 27(67.5%) were multidrug resistant. DEC contribute to the burden of diarrhea in adults in Hamadan. Enteropathogenic E. coli was the most commonly identified DEC strain in the region studied.

Klebsiella is one of the most common species involved in nosocomial and urinary tract infections. Genetic elements such as class 1 integrons have an important role in the resistance development. In this study, the share of class 1 integrons evaluated in clinical Klebsiella isolates in Besat University hospital of Sanandaj, Iran. Isolates identification has done by API20E. Antibiotic susceptibility testing and MIC has done for MDR isolates. For investigating class 1 integrons and gene cassettes, PCR by intI1 integrase, 5’-CS/3’-CS were performed. Integrated gene cassettes were analyzed by PCR-RFLP and sequencing. Pulsed-Field Gel Electrophoresis was carried out for studying of clonality outbreak of isolates. 35 isolated Klebsiella spp. included 29 K. pneumoniae and 6 K. oxytoca. All the isolates were susceptible to carbapenems. Sequencing for prevalent bands showed arr-5, orfD-aacA4 and aad5- dfrA17. Accession numbers for gene cassette were JN222800.1, JN222799.1 and JN222798.1, by order. PFGE Analysis showed 18 clusters in k. pneumonia with clonality relatedness in some cases but no relatedness among K. oxytoca isolates. High prevalence of class 1 integron carrying gene cassettes confirms that integron-mediated antimicrobial gene cassettes are important in Klebsiella spp. resistance profile. Clone diffusions of MDR Klebsiella spp. Which harbor class 1 integrons have threaten potential in the resistance development in our clinical settings.

Staphylococcus aureus is a versatile organism causing mild to life threatening infections. The major threat of this organism is its multidrug resistance. The present study was carried out to investigate in - vitro activity of conventional antibiotics routinely prescribed for methicillin resistant S. aureus (MRSA) and methicillin sensitive S. aureus (MSSA) infections in the Northwest of Iran and other alternating therapeutic agents which are recommended for Gram positive organisms. Clinical isolates of S. aureus were subjected to multiplex PCR for simultaneous speciation and detection of methicillin resistance. Antibacterial susceptibility pattern was determined using disk diffusion. The Minimum Inhibitory Concentrations (MICs) were determined using E-test strips. The results revealed presence of nuc gene in all S. aureus isolates detected phenotypically earlier whereas, mecA gene was observed in 54% of strains. On disk diffusion and MIC determination assay, all MRSA and MSSA strains were susceptible to mupirocin (except one MRSA strain), linezolid and teicoplanin. Six vancomycin intermediate S. aureus strains were detected (VISA) with MIC = 4 μg/mL, 5 of them being MRSA. In disk diffusion assay, 17.3% and 3.7% of isolates showed resistance to rifampin and fusidic acid, respectively. However, MIC50 and MIC90 tests shows promising in – vitro impact. In – vitro mupirocin was found as an effective prophylactic ointment for nasal S. aureus eradication. Our data emphasize the performance of surveillance exercises to outline the existing antibiotics prescription policies and to slow down the emergence of multidrug resistant strains.

Chronic infection in childhood is a leading cause of adeno-tonsillectomy. The aim of this study was to determine the role of M. pneumoniae in children with rhino sinusitis and adenoid hypertrophy. Method and material: This case /control study was carried out in pediatric and ENT wards of Rasul Hospital, Tehran (2007-2009) upon 40 cases with with adenoid surgery and 32 controls. M.Pneumoniae -DNA (PCR) searched in 40 resected adenoid tissue and 31 nasopharyngeal swabs in controls, IgM & IgG antibodies (ELISA) compared between 2 groups, P<0.05 had significant value. Positive PCR observed in 35% of cases and none of controls,positive-IgG:20% of cases (6.4% of controls, P= 0.71), higher in older cases (6 vs. 4 years,p<0.05). Positive –IgM seen in 10% of cases (9.7% of controls, P= 0.74); without any differences for age (6.2/ 5.3 years, p=0.1). Positive PCR was not related to positive IgG (p=0.014), but related to positive IgM (p= 0.1) M. pneumoniae infection proven serologically (IgM&IgG) in10% and 20% of cases.Adding it to positive PCR in adenoid tissue of cases (30%) indicates the prominent role for M. Pneumoniae in adenoid hypertrophy. We conclude that children in Iran infected with M. pneumoniae and obtained immunity between 6-8 years. Adenoid tissue might acts as a reservoir for M. pneumoniae and causing rhino sinusitis concomitant with adenoid hypertrophy in infected children. Theoretically, use of suitable antibiotics to eradicate the M.Pneumoniae, before adenoid surgery (with rhino sinusitis or chronic ear infection) might be helpful but needs future RCT studies.

Dengue has re-emerged as an important arboviral disease causing significant morbidity. It has become hyperendemic in the Indian subcontinent with all the four known dengue serotypes circulating. In the present study we have characterized dengue virus type 3 (DENV-3) circulating in Lucknow, Uttar Pradesh, India. Multiple sequence alignment and phylogenetic tree were constructed to determine the extent of genetic heterogeneity and phylogeny of the dengue virus isolated. Sequencing and phylogenetic analysis of the C-prM gene junction revealed the active circulation and persistence of a new lineage of DENV-3 (genotype III) circulating in this region of India.

Background The risk of adefovir dipivoxil resistance emergence has increased in lamivudine-resistant hepatitis B infected patients. The mutations known as causing adefovir resistance, rtN236T and rtA181V/T, are detected within the D and B functional domain of the HBV polymerase, respectively. In this study, we intended to determine the pre-existing adefovir-resistance mutations in patients infected with LAM resistant mutants prior to starting adefovir therapy. The study included 30 patients with chronic hepatitis B with lamivudine resistance mutations in the YMDD motif that experienced viral breakthrough. After alignment of protein coding sequences, the rtN236T mutation was observed in two (6.6 %) patients, while twenty-eight others had neither rtN236T, nor rtA181V/T mutation. All 30 patients were infected with genotype D of hepatitis B virus. The early detection of LAM-resistance mutations may allow a timely chance of therapy to avoid hepatitis flare-up. This data suggests that monitoring of ADV-resistance mutations in ADV naive patients can be considered in selecting the appropriate anti-viral regimen.

The antifungal activity of selenium nanoparticles (Se NPs) prepared by Klebsiella pneumoniae has been reported previously for different fungi. In the present study, freshly prepared Se NPs produced by K. pneumoniae were purified and characterized by transmission electron microscopy and Energy-Dispersive X-ray spectroscopy (EDS) and its post antifungal effects for two fungi were evaluated. The minimum inhibitory concentrations (MICs) of Se NPs, determined by serial dilution were 250 μg/ml for Aspergillus niger and 2,000 μg/ml for Candida albicans. The effect of exposure of A. niger and C. albicans to Se NPs on later growth was evaluated by incubating the fungi for 1 hour at 25 oC in media containing 0, 1, 2 and 4 x MIC of Se NPs and diluting the cultures 100 times with Se free medium. The kinetics of growth of the fungi in control cultures and in non-toxic Se NPs concentration of, 0.01. MIC, 0.02. MIC or 0.04.MIC were measured. The exposure of A. niger and C. albicans to 2 and 4 x MIC of Se NPs stimulated the growth of both fungi in the absence of toxic concentrations of Se. The strongest stimulation was observed for A. niger. It is concluded that exposure to high concentration of the Se NPs did not have any post-inhibitory effect on A. niger and C. albicans and that trace amounts of this element promoted growth of both fungi in a dose- dependent-manner. The role of nanoparticles serving as needed trace elements and development of microorganism tolerance to nanoparticles should not be dismissed while considering therapeutic potential.

Vaginal candidiasis is a common disease in women during their lifetime and occurs in diabetes patients, during pregnancy and oral contraceptives users. Although several antifungals are routinely used for treatment; however, vaginal candidiasis is a challenge for patients and gynecologists. The aim of the present study was to evaluate terbinafine (Lamisil) on Candida vaginitis versus clotrimazole. In the present study women suspected to have vulvovaginal candidiasis were sampled and disease confirmed using direct smear and culture examination from vaginal discharge. Then, patients were randomly divided into two groups, the first group (32 cases) was treated with clotrimazole and the next (25 cases) with Lamisil. All patients were followed-up to three weeks of treatment and therapeutic effects of both antifungal were compared. Our results shows that 12 (37.5%) patients were completely treated with clotrimazole during two weeks and, 6(18.8%) patients did not respond to drugs and were refereed for fluconazole therapy. Fourteen (43.8%) patients showed moderate response and clotrimazole therapy was extended for one more week. When Lamisil was administrated, 19 (76.0%) patients were completely treated with Lamisil in two weeks, and 1 (4.0%) of the patients did not respond to the drug and was refereed for fluconazole therapy. Five (20.0%) of our patients showed moderate response and Lamisil therapy was extended for one more week. Our results show that vaginal cream, 1% Lamisil, could be suggested as a first-line treatment in vulvovaginal candidiasis.

Nitric oxide (NO) plays a role in thermoregulation and growth of protozoa. This work aimed to add the molecule NO in physiology of protozoa in contact with abused narcotic substances. A sedative drug, morphine, was infused into a cell chamber containing Paramecia. The cell response to the drug was recorded promptly after drug infusion using a potency protocol provided for the first time at this laboratory. A precursor of NO, L-arginine, was treated jointly with drug to involve the NO system in protozoan performance to drug exposure. Marking of NADPH-diaphorase (NADPH-d) was followed to provide data to explain the mechanisms. Morphine, particularly 0.5 to 60 μg/μl, aggregated the Paramecia. The infusion of L-arginine (1 to 8 μg/μl) together with morphine potentiated this effect, though, pre-usage of L-NAME (1 to 8 μg/μl), a blocker of NO production, reversed the response. Notably the activation of NADPH-d in solely morphine or L-arginine plus morphine samples was revealed. However, the expression of marker was attenuated upon pre-infusion with L-NAME. This study introduces a new approach to involve NO in physiology of aggregation of Paramecia following exposure to the misused sedative drug, morphine.