Iranian Journal of Microbiology
Volume:6 Issue: 1, Feb 2014

The increase of infections caused by nontuberculous mycobacteria (NTM) is receiving increasing attention worldwide. Mycobacterium fortuitum is encountered with increasing frequency in clinical laboratories of Iran. Sequence variation of 48 M. fortuitum clinical isolates, were investigated by sequence analysis of the 16S-23S Internal Transcribed Spacer. Twelve different sequence types (sequevar) were identified by sequence analysis of ITS region. Seven previously described sequevar including MfoA, MfoB, MfoC, MfoD, MfoE, MfoF and MfoG identified. Five novel sequevar namely MfoH, MfoI, MfoJ, MfoK and MfoL that were distinctly different from the previously described sequevar were detected among different clinical strains of M. fortuitum, from Iran. This study showed that the ITS region possesses high discriminatory power between the clinical isolates up to the clonal level. The results also suggest the possibility of the existence of predominant clone of M. fortuitum in affected patients in Iran. The data also point to the conclusion that a large variety of M. fortuitum clone can produce disease although certain clones seem to be predominant.

The obligate intracellular bacterium Chlamydia trachomatis causes sexually transmissible diseases in human. Timely and sensitive detection of this pathogen is very important. There are many cross-reactions in bacteriological and serological methods in detection of this type of pathogens. The aim of this study was to achieve a more specific antigen for serological tests. Blood samples were taken from 192 women with suspected chlamydial infection and sera were isolated. ELISA plate wells were coated with recombinant C. trachomatis OMP2 as antigen. Cut-off system was determined with 40 negative sera. The final results of this research were compared with Euroimmun commercial kit. The ELISA system cut-off was calculated at 0.27 using negative sera samples. ODs of positive samples were higher than 0.27 and negative samples were lower than it. We obtained 30 samples (15.62%) as positive and 162 cases (84.37%) as negative. Sensitivity and specificity of the recombinant antigen were 90% and 86%, respectively. This antigen showed no cross-reactivity with sera of patients infected with Hydatid cyst, HCV, Epstein barr virus, HBV, Helicobacter pylori, Toxoplasma gondii, Cytomegalovirus, Mycoplasma, Measles and Varicella zoster virus. The sensitivity and specificity of rOMP2 in ELISA for detection of C. trachomatis were 90% and 86%, respectively. Though the sensitivity was higher than results of Euroimmun commercial kit, its specificity was calculated lower than reference kit.

Helicobacter pylori has been strongly associated with peptic ulcer diseases, chronic gastritis, ulcers, and reported as a risk factor for gastric cancer, too. The vaculating cytotoxin (vacA), the cytotoxin associated genes (cagA), the induced by contact with epithelium factor antigen (iceA gene), blood adhesion binding antigen (babA2), and outer membrane protein oipA have been described as different virulence factors of H. pylori. The aim of this study was to investigate the prevalence of the vacA, cagA, cagE, iceA, babA2 and oipA genotypes of H. pylori isolates from patients with upper gasterointestinal problem or dyspepsia. H. pylori isolated from endoscopic biopsies obtained from 222 studied patients. PCR was done only on cultured positive samples. The vacA alleles, cagA, cagE, iceA, babA2 and oipA genotypes were determined by PCR. The isolation rate of H. pylori strains from culture of gastric biopsies was 16.7%. The vacA alleles s1, s2, m1 and m2 were detected in 20 (54.1%), 14 (37.8%), 9 (24.3%) and 23 (62.2%) isolates, respectively. VacA s1c genotype was detected in 70.3% of isolates. s1m2 was the most frequent vacA allelic combination in the examined H. pylori strains. The cagA gene was detected in 62.2%, cagE in 40.5%, iceA1 in 48.6%, iceA2 in 16.2%, oipA in 81.1% (95% CI: 0.0902-0.1798) and babA2 in 94.6% (95% CI: 0.113- 0.207). A significant correlation was observed between vacAs1 and cagA genotypes (P < 0.008), vacAs1/cagE (P = 0.001), vacAs2/cagA (P < 0.047), and vacAs2/cagE (P = 0.016) with Non-ulcer dyspepsia; but there were not observed any correlation between other virulence markers. No significant correlation was found between the existence of vacA, cagA, cagE, iceA, babA2, and oipA genes with peptic ulcer diseases and non-ulcer dyspepsia groups of studied patients.

Acinetobacter causes a wide variety of illness in debilitated and hospitalized patients. Carbapenem resistance in Acinetobacter is an emerging problem and is a cause of concern as many nosocomial infections with Acinetobacter are resistant to most other antibiotics. The present study was aimed to study metallo-β-lactamase (MBL) production in Acinetobacter species. During one year prospective study, all isolates of Acinetobacter obtained from various clinical samples like respiratory, pus, blood and others were included. Antimicrobial susceptibility testing was done by standard Kirby Bauer disk diffusion method. Metallo β-lactamase (MBL) detection was done by imipenem-EDTA combined disk method. Among 1017 isolates, 964 were A. baumannii, 48 were A. lwoffii and 5 were A. hemolyticus. Out of these, majority of the isolates were obtained from respiratory samples, followed by pus. A. baumannii showed high level of resistance to cephalosporins, cotrimoxazole and piperacillin. A. lwoffii and A. hemolyticus showed lesser resistance to all antibiotics. Imipenem resistance was observed in 389 (40.3 %) isolates of A. baumannii and MBL activity was seen in 80.3% of isolates. MBL positive isolates of A. baumannii showed higher resistance as compared to MBL negative isolates. This study demonstrated that multidrug resistant strains of Acinetobacter are common in tertiary care hospitals. Unwarranted and unrestricted usage of antibiotics is associated with emergence of resistance in nosocomial pathogens. Regular monitoring and documentation of carbapenem resistant is crucial in developing strategies to control infection due to these bacteria.

Bacteria are the primary etiology of pulpal and periradicular pathosis. In endodontically treated teeth with persistent infections only one or a few bacterial species are present of which the most important is Enterococcus faecalis. The aim of this study was to compare antibacterial efficacy of canal disinfectants including 5.25% sodium hypochlorite, 2% chlorhexidine, MTAD (a mixture of doxycycline, citric acid and a detergent (Tween 80) and 830 nm diode laser.Methods and Materials: The canals of 135 extracted single rooted human teeth were prepared using rotary instruments. The canals were contaminated with Enterococcus faecalis for 4 weeks and then were divided into 4 groups of 30 teeth in each, a positive control group containing 10 teeth and a negative control group of 5 teeth. After using the disinfectants, samples obtained from canals by paper points and also shaving the canal walls were cultured. The Kruskal-Wallis test was used to analyze the results. The results showed the bacterial reduction as follows: 99.97 ± 0.14 for sodium hypochlorite, 99.65 ± 1.13 for chlorhexidine, 97.56 ± 6.36 for laser and 96.91 ± 5.60 for MTAD. The count of CFU obtained from dentin shavings was: 16/96 ± 91/23 for sodium hypochlorite, 82/73 ± 186/63 for chlorhexidine, 47/26 ± 112/21 for laser and 341/34 ± 1139/83 for MTAD. According to the results, sodium hypochlorite was the most effective agent against Enterococcus faecalis.

Clostridium perfringens is more prevalent type of clostridia genus isolated from the intestinal tract of ostrich (Struthio camelus). Necrotic enteritis (NE) is a potentially fatal gastrointestinal (GI) disease of poultry and other avian species, which produces marked destruction of intestinal lining in digestive tract caused by C. perfringens. Pathogenicity and lesions are correlated with the toxins produced, thus toxin typing of the bacterium has diagnostic and epidemiological significance. The aims of the present study were to determine the biotypes of C. perfringens among ostrich’s farms either diseased and healthy ones and to screen the isolates for major toxin genes (cpa, cpb, etx, and iA, cpb2, and cpe). Thirty isolates of C. perfringens were obtained from NE-positive and NE-negative ostrich flocks in Khorasan-e-Razavi porvince and analyzed by multiplex PCR assay. All isolates were positive for alpha toxin gene (cpa) and five of those were positive for beta toxin gene (cpb). The presence of cpb2 gene was detected in a high percentage of isolates originating from both healthy (93.3%) and diseased flocks (80%). None of the isolates carried enterotoxin gene (cpe). The results suggest that types A and C of C. perfringens are the most prevalent types in ostrich in Iran. Due to detection of beta2 toxin gene in isolates from both healthy and diseased birds, it appears that the presence of cpb2 is not considered a risk by itself.

Varicella zoster virus (VZV) can cause life-threatening disease in pregnant women. The aim of this study was to identify the VZV immune status in pregnant women and also determine the validity of self-reported history for chickenpox. Serologic testing for VZV was performed for 400 pregnant women attending prenatal care at clinics located in two teaching and referral hospitals in Tehran, Iran. The Enzyme Immunoassay method was used to assess IgG antibodies against VZV. A total of 400 pregnant women, aged 16-43 years (median: 27 years, mean: 27.6 ± 5.9 years), were examined in which 361 (90.3%) were found to be seropositive. Sensitivity, specificity and positive and negative predictive values of patients’ self reported history were 51.8%, 71.7%, 94.4% and 13.8% respectively. Serologic screening for VZV in pregnant women seems crucial. We suggest considering the pregnant women as the target group for future immunization programs in Iran.

There is a concern on safety of human Fresh Frozen Plasma (FFP) as it is a source of some medicinal products. The possibility of transmission of blood-borne are reported often due to emerging viruses. There are some Pathogen Reduction Technologies (PRT) to inactivate viruses. Methylene Blue (MB) based method is one of them. The aim of this study was to examine new designated device to inactivate model viruses. Four model viruses were used in this study:Vesicular stomatitis virus (VSV), Herpes Simplex Virus I (HSV-1), Bovine Viral Diarrhea Virus (BVDV) and Polio Virus. 50% Tissue Culture Infective Dose (TCID 50) and Reed–Muench Methods were used to titer the viruses. MB in two final concentration of 0.1 μM and 1 μM and illumination in about 627 nm with red LED (Lamp Emitting Diode) for 15, 30, 45 and 60 minutes were used. Three replicates employed for each experiments. 1 μM concentration of MB showed more effective than 0.1 μM in all designed illumination period for inactivation of HSV, VSV and BVDV. This method also demonstrated best results for enveloped model viruses. The most Log reduction for HSV, VSV and BVDV were 6.28, 5.54 and 6.22, respectively. For HSV and BVDV inactivation, the best illumination period was 45 minutes. Model viruses showed sensitivity combination of MB and illumination using red LEDs. As results show this device could inactivate model viruses and reduce their titer very close to approved commercial devices, in compare.

Poultry are more susceptible to receiving and spreading of fungal infections in exact conditions. The goal of this study was to identify the normal fungal flora and dermatophytes agent of the combs and wattles of adult native chickens in Tehran, Iran. A total of 150 combs and wattles samples were collected by skin scraping or brushing of the margin of the suspected lesion and skin of organ. The mycological analyses were performed by direct microscopy and culture media. One hundred and ninety fungi were isolated from the combs of 150 native chickens’ samples that including non-dermatophytes isolates 165 (86.8%), dermatophytes 6 (3.2%) and yeast 19 (10%). Among different fungal isolates, Aspergillus was the predominant species. Our results showed that human in contact with poultry, both at the household and the industrial level, have a clear risk factor for exposure to fungal pathogens, especially dermatophytes.

Pomegranate fruit is a rich source of bioactive compounds. The serious concern over unprocessed fruit juices is microbial contamination, which effectively inactivated by thermal processing, but it significantly affects juice functional compounds. Therefore, the effect of gamma irradiation and ultrasonic on inoculated microbial to pomegranate juices was studied.

Two pomegranate cultivars were purchased from the Agricultural Research Center of Saveh, and their juices were extracted by a manual device and immediately centrifuged. Then the studied microorganisms were resuspended in sterile pomegranate juices. The juices were continuously sonicated at amplitude levels of 50, 75 and 100% and times of 0, 3, 6, 9, 12 and 15 min at temperature of 25 ± 1°C. Irradiation treatment was also carried out at various doses of 0, 0.5, 1.0, 1.5, 2.0, 2.5 and 3 kGy.

The results showed that lower amplitude levels (50 and 75%) did not inactivate E. coli and S. cerevisiae significantly (<1.5 log reduction), while at 100% amplitude level for 15 min, their population reduced by 3.47 and 1.86 log cfu/mL, respectively. Gamma irradiation treatment at 1 kGy also reduced E. coli by 6.66 log cfu/mL, whereas at 3 kGy it reduced S. cerevisiae by 5.08 log cfu/mL.

The low-dose gamma irradiation could potentially inactivate the studied microorganisms compared to the sonication, which had less destructive effects on their populations. Further research is needed to determine the effect of these methods on other fruit juices for industry purposes.