Comparison of paraffin bait, humic acid vitamin b agar and paraffin agar methods to isolate nocardia from soil

The Isolation of Nocardia species is complex and time-consuming, which is due to rapid growth of adjacent bacteria. Because of the importance of a specific medium with the ability of controlling intrusive microorganisms, this study aimed at comparing three laboratory methods to introduce the reliable isolation technique for Nocardia species. The soil samples were collected from different regions of Tehran province, Iran, and carefully transferred to the laboratory. The samples were cultured in three different media including Paraffin Baiting,Humic acid vitamin B agar and Paraffin agar, and incubated for 3-4 weeks at 35 °C. Of 110 soil samples, 31 Nocardia isolates [28.18%] were obtained from the media including Paraffin Baiting, [19; 17.27%], Humic acid and vitamin B agar [4; 3.63%], and Paraffin agar,[8; 7.27%].because of high rate of isolation, low cost and the clearance of colonies suspected nocardia, Paraffin Bait technique is more reliable and efficient compared to the other methods

[Frequency of sialic acid binding adhesin gene in Helicobacter pylori isolated from patient with gastroduodenal diseases]

Sialic acid binding adhesin gene is one of the most important factors contributing to adhesin of Helicobacter pylori [H. pylori] to epithelial cell layer of stomach. The prevalence rates of sialic acid binding adhesin gene vary in different geographic areas. The aim of this study was to determine the frequency of sialic acid binding adhesin coding gene in the patients with different gastroduodenal diseases. This is a cross-sectional study. One hundred twenty patients with GI symptoms were enrolled in this study. Two gastric biopsy specimens were taken from each of the patients for rapid urease test [RUT] and DNA extraction. Presence of H. pylori was investigated by RUT and urease A gene [ureA] PCR. sialic acid binding adhesin gene was detected by using gene specific primers. Among 120 samples, presence of H. pylori was confirmed in 82 cases, of which 64 strains [78%] were positive for sialic acid binding adhesin gene. The frequency of this gene was 84.6%, 86.7%, 77.8% and 72.2% for gartric cancer, gastric ulcer, duodenal ulcer and gastritis [%66.7] respectively. The frequency of sialic acid binding adhesin gene in different samples was almost the same. Discrepancies in the frequency of this gene in different studies may be related to geographical diversity or use of different primers for detection of this gene

Assessing the effect of highly cited papers on the impact factor of journals in the field of public health

The aim of this study was to appraisal the effect of highly cited papers in the field of public health and find out whether the unusual citations affect the ranking order of the journals in this field or not. A total number of 142 journals titles were listed in Journal Citation Report [ISI Thomson] in the field of "Public, Environmental and Occupational Health". All but one of them had published papers at least for a year from 2009 to 2010. Journal title, number of citations and publication year of 45685 papers were collected from ISI web of knowledge database at December 25, 2011. About half of the papers [23226] had no citations and 89.4% [40835] had less than 6 citations. We concluded that the ranking of journals in the field of public health is not affected by the individual papers with unusual number of citations

Evaluation of culture and pcr methods for diagnosis of group b streptococcus carriage in Iranian pregnant women

Group B streptococcus [GBS] is one of the most important cause of morbidity and mortality among newborns especially in developing countries. It has been shown that the screening approach rather than the identification of maternal clinical risk factors for early-onset neonatal GBS disease is more effective in preventing early-onset GBS neonatal disease. The objective of this study was to detect GBS among clinical samples of women using PCR and standard microbiological culture. Samples were taken from 375 women at 28-38 weeks of gestation during six month from January 15 till June 15, 2011 from a hospital in Tehran, Iran. Samples were tested by standard culture using Todd- Hewitt broth, blood agar and by PCR targeting the cfb gene. Among the 375 women, 35 [9.3%] were identified as carriers of group B streptococci on the basis of the results of the cultures of specimens, compared to 42 [11.2%] on the basis of PCR assay. We found that GBS can be detected rapidly and reliably by a PCR assay in vaginal secretions from women at the time of delivery. This study also showed that the rate of incidence of GBS is high in Iranian women

Evaluating the efficiency of lettuce disinfection according to the official protocol in Iran

The objective of this study was to evaluate the efficacy of Sanitization of Lettuce according to the protocols set forth by Iranian Ministry of Health and Medical Education for reducing populations of total coliform, fecal coliform, and helminth eggs present on lettuce. In the present study, we determined the load of total coliform, fecal coliform, and parasites of lettuce. The lettuce was sanitized by protocol of Iranian Ministry of Health and Medical Education. The protocol consists of 3 levels to disinfect the fruits and vegetables. The procedure was as follows: first washing stage. The leaves of leafy vegetables washed with tap water, second stage, separation of helminth eggs by 3 to 5 droplets of detergent per liter for 5 min; third stage, disinfection of vegetables by calcium hypochlorite solution [with 200 mg/1 free chlorine] for 5 min; and finally the disinfected vegetables were washed with tap water. The average initial levels of total coliform and fecal coliform in the samples were 3.36 Iog[10]cfu/g and 2.31 log[10]cfu/g, respectively. Helminth eggs were not detected in any of the samples tested. The efficiency of total coliform and fecal coliform removal were 78.1% [0.75 Iog[10]cfu/g] and 79.6% [0.67 Iog[10]cfu/g], respectively, after washing. This increased up to 94.8[1.44 Iog[10]cfu/g] and 98.5% [1.90 log[10]cfu/g] after the use of detergent. Chlorine disinfection rose these amounts up to 98.3% [2.18 Iog[10]cfu/g] and 100% [2.31 Iog[10]cfu/g], respectively. By applying the protocol large parts of microorganisms existing on lettuce have indeed been removed

[Frequency of pharyngeal neisseria carriage among 10-12 years old pupiles in Tehran, Iran]

Neisseria meningitidis is an obligate pathogen of human and temporary colonizes the mucosa of upper respiratory tract. This study was done to determine the frequency of pharyngeal Neisseria Carriage among 10-12 years old pupiles. This cross sectional study was carried out on 364 pupiles at four primary schools in Tehran during spring 2008 and winter 2009. The samples were collected from pharyngeal region and were cultured on Thayer-Martin Agar. Among 364 collected samples from pharynx of pupiles, Neisseria meningitidis not found on the selective media, but three of pupiles were carrier of Neisseria lactamica. This study showed that Neisseria meningitides colonization was not observed in the pharynx of 10-12 years old pupiles

Prevalence of genes encoding Bi-component leukocidins among clinical isolates of methicillin-resistant staphylococcus aureus

Staphylococcus aureus has been recognized as a major human pathogen and is the major cause of nosocomial infections. Gamma-toxin, leukocidin and other bi-component toxins are a family of proteins encoded by the hlg and luk-PV, respectively. Panton-Valentine leukocidin [PVL] is an example of these toxins and causes leukocyte destruction and tissue necrosis. The aim of this study was to determine the prevalence of bi-component leukocidin in Methicillin - Resistant Staphylococcus aureus [MRSA] isolates in staphylococcal infections. Collectively, 143 isolates of S. aureus were obtained from Tehran University of Medical Sciences hospitals and confirmed with biochemical tests. Then polymerase chain reaction was used to detect luk-PV loci and luk-E/D. Coagulase gene was used as internal control. The antibiotic susceptibility patterns of isolates were determined using disk diffusion method. Out of 149 S. aureus isolates 24.2% were luk-PV positive and 73.8% were luk-E/D positive. There was PVL-positive MRSA isolates with high prevalence in evaluated hospitals. The diseases from these bacteria are with extensive necrosis, leucopenia and even death. We desire that, prevent from progress and death by diagnosis and right treatment

Antibiotic resistance to third generation cephalosporins due to CTX-M-type extended-spectrum beta-lactamases in clinical isolates of Escherichia coli

Organisms producing CTX-M-beta-lactamase are emerging around the world as a source of resistance to oxyiminocephalosporins such as cefotaxime. However, the laboratory detection of these strains is not well defined. The aim of this study was to determine the presence and prevalence of known CTX-M-beta-lactamases genes in clinical isolates of Escherichia coli from hospitals of Tehran. During six months [September to February, 2006], 160 clinical isolates of Escherichia coli collected from three university hospitals of Tehran. Phenotypic screening and confirmation tests for ESBL detection was according to CLSI advised. All of the ESBL-producing isolates were examined by PCR for presence of bla CTX-M genes. Primary phenptypic tests revealed that 56.69% [n=89] of E. coli isolates produced ESBLs. In confirmatory tests by use of clavulanic acid, ESBL production were confirmed [P+C+] in 96.7% [n=86] of isolates with primary positive test. The presence of an ESBL was not confirmed [P+C-] in 3.3% [n=3] of the screen positive. Of all screen positive isolates, 34 [35.78%] were positive for bla CTX-M genes from the CTX-M-I group, indicating CTX-M-1-like beta-lactamases and Two [2.1%] were positive for bla CTX-M genes from the CTX-M-III group, indicating CTX-M-3-like beta-lactamases. The remainder 59 [62.2%] were negative for bla CTX-M genes. The levels of resistance to ceftazidim were remarkably varible among CTX-M producers. This study provides futher evidence of the global dissemination of CTX-M type ESBLs and emphasize the need for their epidemiological monitoring

Molecular detection of common bacterial pathogens causing meningitis

The clinical diagnosis of meningitis is crucial, particularly in children. The early diagnosis and empiric antibiotic treatments have led to a reduction in morbidity and mortality rates. PCR and the enzymatic digestion of 16SrDNA fragment which is produced by universal primers led up fast and sensitive determination. The purpose of this study was to investigate a rapid method for detection of common bacterial pathogens causing meningitis. According to the gene encoding 16SrDNA found in all bacteria, a pair of primers was designed. Then the universal PCR was performed for bacterial agents of meningitis [Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influenzae, etc.] by employing broad- range DNA extraction method. The obtained universal PCR products were digested with restriction enzymes [HaeIII, AluI and MnlI] to identify bacterial species. By the enzymatic digestion of the universal products of each standard strain of the above bacteria, specific patterns were achieved. These specific patterns may be used for comparison in CSF examination. The analytical sensitivity of the assay was approximately 1.5X10[2] CFU/ml of CSF even in samples with high amount of proteins. The universal PCR coupled with enzymatic digestion can be used to detect and identify bacterial pathogens in clinical specimens rapidly and accurately. Molecular diagnostic of bacterial meningitis, though expensive and labor-intensive, but is valuable and critical in patient management

[Detection of E.coli strains containing shiga toxin [stx1/2] gene in diarrheal specimens from children less than 5 years old by PCR technique and study of the patterns of antibiotic resistance]

Shiga toxin- producing Escherichia coli [STEC] is an emerging bacterial pathogen in developing countries that causes several diseases such as diarrhea, hemorrhagic colitis [HC] and hemolytic uremic syndrome [HUS], particularly in children. Aim of the research was detection of STEC in diarrheal specimens from under 5 year olds and study of the patterns of antibiotic resistance of these strains. In the study, 300 fecal samples were collected from children with diarrhea referring to Ali Asghar Hospital. E.coli species were isolated by standard bacteriological and biochemical tests. Presence of shiga toxin genes [stx 1/2] was investigated by PCR technique [Qiagen]. Antibiogram test for strains containing the toxin gene was performed using 16 different antibiotic discs [MAST] by disc diffusion agar [Kirby- Bauer] method. From 39 E.coli isolates, 9[23.1%] strains were detected by PCR to contain stx 1/2 gene. One strain was resistant to all 16 antibiotics. All the STEC strains were sensitive to meropenem [MRP], imipenem [IMI], gentamycin [GEN] and nitrofurantoin [NI]. 4[44.44%] strains showed multi-drug resistant pattern. All these 4 strains were resistant to cotrimoxazole [SxT]. Also, 6[66.66%] strains were resistant to at least one antibiotic. In Iran, shiga toxin-producing Escherichia coli [STEC] may be a commonly bacterial pathogen causing diarrhea, particularly in children. Therefore, we should use new techniques for investigation of these strains. Increase in number of emerging and new strains that could be resistant to classic antibiotics such as cortimoxazole may be foreseen. It is suggested that antibiotics prescription programs in treatment of diarrhea causing E.coli strains be updated

[Cloning and Sequencing of sacol a novel gene from Staphylococcus aureus]

Natural staphylococcal infections and vaccines based whole bacteria lead to poor antibody responses, but recent research reveals that specific antibodies based on recombinant staphylococcal antigens are much more protective. Sacol is a novel antigen that its structural and immunological traits poorly characterized. This research aimed to clone of sacol, a novel gene from Staphylococcus aureus. The specific primers with suitable restriction sites were designed and sacol amplified by PCR. The sacol and plasmid were produced as sticky ends by restriction enzymes NdeI and XhoI. To amplify the recombinant plasmid the pET21 sacol transferred into competent cell E.coliTOP10. The recombinant plasmid harvested from the host and analyzed by restriction enzymes and sequencing. Finally, sacol gene analyzed by bioinformatics tools. The sacol gene has 723bp which amplified, cloned and sequenced successfully. Sacol is highly conserved in Staphylococcus aureus strains. Moreover, software analysis shows that sacol encodes a protein with 32KDa molecular weight [267 amino acids] which has similarity with C51 peptidase in N-terminal with one alpha helix and 14 beta sheets. The sacol gene is conserved in majority of Staphylococcus aureus strains and may exist and express in most of staphylococcal infections. The role and regulation of the gene is thus of great interest

Prevalence of helicobacter pylori Cag E genotypes, in patients with non-ulcer dyspepsia, peptic ulcer and gastric carcinoma

Helicobacter pylori are a bacterial pathogen evolved to chronically colonize the gastric epithelium and causes gastritis, peptic ulcers, and even gastric malignancies in few infected humans. More recently, a pathogenicity island has been identified within the H. pylori genome that contains a cluster of genes, including cagE. The aim of the current study was to investigate the prevalence of cagE genotypes of H. pylori isolates from patients with NUD[Non Ulcer Dyspepsia], peptic ulcer and cancer. 150 Gastric biopsy specimens obtained from patients were inoculated onto a Brucella Columbia Agar containing 5% sheep for 3 to 5 days at 37°C under micro aerobic conditions [5% O2, 5% CO2, and 90% N2]. After DNA extraction, genotyping of the cagE gene was performed by PCR amplification using the primers. PCR products were separated by 1% agarose gel electrophoresis and examined under UV illumination. Of 92 positive cultures, 34, 28, 20, and 10 isolations were obtained from patients with NUD, duodenal ulcers [DU], gastric ulcers [GU] and gastric cancer [GC], respectively. The frequency of cagE gene was 88/24%, 100%, 85%, 100% and within isolates of patients with NUD, DU, GU and GC, respectively. The presence of cagE in patients with Helicobacter pylori infection is not a marker for predicting or diagnosing the resultant diseases

Evaluation of PCR method for diagnosis of Group B Streptococcus carriage in pregnant women

Group B Streptococcus [GBS] [Streptococcus agalactiae] is the leading cause of morbidity and mortality of newborn infants and accounted as a leading factor causing septicemia after birth in mothers. Infections in infants are usually acquired by contact with the genital tract of the mothers during labor and delivery. In two last decades, significant progress toward detection, prevention and treatment of pregnant women carrying GBS has been achieved. A rapid screening test for GBS that could accurately identify pregnant women carrying the bacteria at the time of delivery would obviate the need for prenatal screening. The standard method for the diagnosis of GBS colonization consists of culturing vaginal and anal secretions in a selective broth medium which inhibits the growth of other microorganisms. Today, it is accepted that PCR has a high sensitivity and specifically in diagnosis. The goal of this study was to screen pregnant woman carrying GBS by PCR. Samples were taken from anal and vaginal mucus of 125 pregnant women who were at 28-38 weeks of ingestion by swab. Samples were tested by standard culture using Todd Hewitt Broth and Blood Agar and also by PCR using primers specific for cfb gene. Culture identified 10 [8%] women as carriage of GBS out of 125 women tested. On the other hand, the PCR assay could identify 12 [9/6%] women positive for GBS. In comparison to culture results, sensitivity, NPV, specificity, and PPV of PCR were 100%, 100%, 98%, and 83%, respectively. The time required for PCR assay and culture were 2h and 36h, respectively. We found that GBS can be detected rapidly and reliably by a PCR assay using combined vaginal and anal secretions from pregnant women at the time of delivery. Also this study shows that the rate of incidence of GBS is high in Iranian pregnant women. We, therefore, recommend screening of pregnant women for detecting of GBS emphatically

Genotyping of Helicobacter pylori strains isolated from patients with NUD, DU, GU and GC by RAPD-PCR

Helicobacter pylori is a genetically diverse gastric pathogen that chronically infects billions of people worldwide, typically beginning in infancy and lasting for decades. It is a major cause of peptic ulcers and it is an early risk factor for gastric cancer which is the most frequently lethal malignancy globally. This project was designed to genotype H. pylori isolates isolated from patients with NUD, DU, GU and GC by the polymerase chain reaction [PCR]-based on Randomly Amplified Polymorphic DNA [RAPD] fingerprinting technique. Eighty patients admitted to the gastroenterology unit at Sharyati hospital in Iran were included in this study. Gastric biopsy specimens were inoculated onto selective medium then were cultured for 3 to 5 days at 37 °C under microaerobic conditions. Genomic DNA was extracted using a commercially available Qiagen kit. RAPD-PCR was used to genotype isolates. Six different RAPD patterns [A-F] were seen in more than one isolate which were as follow; pattern A: 9 [16.98%], B: 6 [11.33%], C: 5 [9.43%], D: 3 [5.66%], E: 2 [3.77%] and F: 2 [3.77%]. Twenty six [49.06%] of 53 isolates showed a unique RAPD pattern that were not similar to each other. A significant relationship was not seen between a single RAPD pattern and a gastric disorder [P>0.05]. The results of this study suggest a high level of DNA sequence diversity among H. pylori isolates and it is better to use sequencing method for surveying of Helicobacter pylori genome rather than RAPD-PCR

Characterization of vancomycin resistant enterococcus faecium

To determine the species distribution, updated drug susceptibility patterns and genes conferring resistance in clinical vancomycin resistant enterococcal [VRE] isolates. Clinical enterococcal isolates collected during 7 months, from September 2005 to April 2006 from hospitalized patients and outpatients were studied. Twenty five VRE were isolated from 450 enterococci samples [5.6%]. VRE isolates were subjected to antibiotic susceptibility tests. Genotype of these isolates was determined by PCR. All of the isolates were E. faecium and carried the vanA gene. Antibiotic susceptibility tests showed that the isolates were resistant to ampicillin 25[100%], ciprofloxacin 25[100%], gentamicin 24[96%], erythromycin 25[100%], tetracyclin 10[40%] and chloramphenicol 2[8%]. VRE strains were resistant to three antibiotics and were susceptible to new antibiotics linezolid and dalfopristin- quinupristin. Switching to treatment with these antibiotics would relieve the problem for a short time

prevalence of infected stones in the urinary tract and their relationship to urease positive bacteria

To determine the prevalence of infected stones in the urinary tract and their relationship to urease positive bacteria and whether a positive urine culture signifies infected stone profile. This study was conducted on 168 patients [116 males and 52 females] with a mean age of 37 years. The analysis was performed on: [1] Urine specimen before operation, [2] Urine around the stone before stone retrieval and [3] Stones. Urine and stone culture was performed on blood agar [BA] and Eosin Methylene Blue [EMB] for gram staining, Brucella agar enriched with vitamin K and Thioglycolate medium for anaerobics and uroplasma urealyticum inside PPLO culture. Urease was determined on urea broth and urea agar media. Chemical analysis of the stone was done by Merck kit. Seven cases of culture were positive for infected stones [64%] while 6 cases of non-infected stones grew microorganisms [3.8%]. Infected stones comprised 6.5% of all the stones. Proteus mirabilis and Pseudomonas aeruginosa were the most commonly encountered bacteria [18%]. Urease positive bacteria were found to be 54.5% in the infected stones and 6% in the non-infected stones. Urine and stones samples showed that only 14.5% had the same type of bacteria. Other factors besides bacteria play a role in stone formation in the urinary tract and infected stones can be produced in non-infected urine also