International Journal of Enteric Pathogens
Volume:4 Issue: 1, Feb 2016

Context: Leptospirosis is a worldwide zoonotic infection which appears to be a re-emerging health problem. The clinical features of the disease are broad ranging, but are often similar to those of other infections. As a result, the accuracy of a clinical diagnosis of leptospirosis is low and confirmation requires the use of laboratory tests.Evidence Acquisition: The disease is usually diagnosed in the laboratory by different methods such as direct microscopy, culture, serological methods and molecular methods. The microscopic agglutination test (MAT) is considered the reference test among the several serological methods for leptospirosis diagnosis. However, isolation and identification of the microorganism allows for definitive diagnosis, and provides for epidemiological and prophylactic studies of this disease. Therefore, culture is a golden standard method. Polymerase chain reaction is a rapid, sensitive and specific means of detecting leptospiral infection, in contrast to serology tests. Further benefit is the ability to identify early infection especially during the first few days of the disease even before antibodies are detectable. Choice of test for diagnosis of leptospirosis depends on the stage of the disease. An ideal test will need to discriminate between leptospirosis and a broad spectrum of diseases that cause acute febrile illness and have overlapping clinical presentations. Although detection of antibodies is by itself no proof of a current infection, serological methods (such as MAT and ELISA) are often the most appropriate diagnostic methods.

Bacteria in foodstuff are the most important agent of foodborne disease. Aside from their infectious effects, obligate aerobes have a respiratory metabolism with oxygen as the terminal electron acceptor. Therefore, they can produce reactive oxygen species and free radicals in contaminated food. Malondialdehyde (MDA) is a product of lipid peroxidation used as an indicator of oxidative stress. This study aimed to evaluate the oxidative damage produced by two common food pathogenic bacteria in foodstuff. The egg yolks were incubated with different dilutions (105,106, and 107) of Staphylococcus aureus and Salmonella enteritidis at 37°C for 20 hours. The level of MDA in egg yolk was measured by fast and simple enzymatic or colorimetric methods, such as the thiobarbituric acid reactive species method. The high group (107) had a higher MDA level of 1.97 ± 0.11 (µg MDA/g) in S. aureus and 1.65 ± 0.27 (mg MDA/L) in S. enteritidis than the control (0.90 ± 0.13 mg MDA/L). We concluded that common food pathogenic bacteria can induce oxidative damage in foodstuff aside from other common problems. Heating or sterilization methods cannot protect foodstuff from the damage caused by the presence of pathogenic bacteria.

Uropathogenic Escherichia coli (UPEC) are a common causative agent of urinary tract infections. Strains of UPEC encode a number of virulence factors that facilitate their dissemination and persistence within the host. To diminish the burden of UPEC, using effective preventive measures, data on virulence factor prevalence in different geographic regions must be assessed. As no such data was available for this geographic region of Iran, the purpose of this study was to analyze the prevalence of ten UPEC virulence genes among 100 E. coli isolates collected from patients with urinary tract infections (UTI) in Zabol, Iran.Patients and One hundred UPEC obtained from patients with urinary tract infection were screened by the polymerase chain reaction (PCR) with primers specific for the following UPEC virulence genes: astA (enterotoxins), cdtB (enterotoxins), cvi/cva (colicin V operon), ibeA (an invasive protein), iss (increased serum survival protein), iutA (aerobactin), kpsII (group 2 capsule), neuS (K1 polysialyltransferase), tsh (an adhesive and proteolytic protein), and vat (vacuolating autotransporter toxin). Amongst the total of 100 UPEC isolates, 99 (99%) isolates were found to carry the studied virulence genes. Twenty-six different virulence patterns were identified. The prevalence of astA, cdtB, cvi/cva, ibeA, iss, iutA, kpsII, neuS, tsh and vat were 29%, 0%, 19%, 67%, 47%, 99%, 98% 96%, 1% and 18%, respectively. We concluded that major differences exist in the prevalence of virulence factors between different UPEC isolated from different countries. Detecting these genes as primary controllers of UPEC virulence may aid in better management of related infections.

Escherichia coli strains are common pathogens that can cause urinary tract infections (UTIs). They are classified into phylogroups based on three genetic markers: chuA, yjaA, and TspE4.C2. The E. coli strains that cause UTIs possess several genes that encode urovirulent factors and antimicrobial-resistance phenotypes. We determined the phylogenetic groups of E. coli isolates from UTI cases in Sabzevar, Iran, the prevalence of certain virulence genes, and the antibiotic-resistance phenotypes in these strains. The aim of this study was to assess the correlation of detected E. coli phylogroups in female UTI patients with the antibiotic-resistance pattern and the distribution of certain virulence factors among the phylogroups. Ninety-three E. coli isolates from 150 women with UTI were studied. Three genetic markers were detected for phylogenetic grouping of strains, and four virulence determinants were analyzed with multiplex-PCR, including the genes for hemolysin (hly), aerobactin (iucD), P fimbriae (pap), and S/F1C fimbriae (sfa/focDE). The antibiotic-resistance phenotypes were also determined. The isolates from UTI cases were distributed within phylogroups A (31%), B1 (10%), B2 (28%), and D (31%). The prevalence of iucD, hly, pap, and sfa/focDE virulence genes was significantly associated with groups B2 and D. The most-resisted antibiotics were cefazolin (93%) and co-trimoxazole (68%), while the isolates were most sensitive to nitrofurantoin (1%) and imipenem (2%). The phylogroups of E. coli isolates from UTI cases showed that groups D, B2, and A are prevalent in women in Sabzevar, as the dominant pathogenic phylogroups. The comparison showed that there was no significant difference in the occurrence of virulence factors or in the distribution of antibiotic resistance between urinary E. coli isolates, but the virulence genes were distributed more into groups B2 and D, respectively. Our study showed that the highest sensitivity was to nitrofurantoin and imipenem, but the decision on a treatment strategy remains based on the physician’s diagnosis and the antimicrobial-resistance tests.

Cholera as an endemic disease remains a health issue in Iran despite decrease in incidence. Since forecasting epidemic diseases provides appropriate preventive actions in disease spread, different forecasting methods including artificial neural networks have been developed to study parameters involved in incidence and spread of epidemic diseases such as cholera. In this study, cholera in rural area of Chabahar, Iran was investigated to achieve a proper forecasting model. Data of cholera was gathered from 465 villages, of which 104 reported cholera during ten years period of study. Logistic regression modeling and correlate bivariate were used to determine risk factors and achieve possible predictive model one-hidden-layer perception neural network with backpropagation training algorithm and the sigmoid activation function was trained and tested between the two groups of infected and non-infected villages after preprocessing. For determining validity of prediction, the ROC diagram was used. The study variables included climate conditions and geographical parameters. After determining significant variables of cholera incidence, the described artificial neural network model was capable of forecasting cholera event among villages of test group with accuracy up to 80%. The highest accuracy was achieved when model was trained with variables that were significant in statistical analysis describing that the two methods confirm the result of each other. Application of artificial neural networking assists forecasting cholera for adopting protective measures. For a more accurate prediction, comprehensive information is required including data on hygienic, social and demographic parameters.

Cholera is a potentially life-threatening acute diarrheal disease caused by the toxigenic bacteria, Vibrio cholerae. Antibiotics should be selected using local antibiotic susceptibility testing patterns. This study was performed to identify the patterns of antimicrobial resistance in isolates collected from laboratory-confirmed cases of cholera during three years, from 2011 to 2013. All isolates at the Health Reference Laboratory were tested by the Minimum Inhibitory Concentration (MIC) Test using Liofilchem against ciprofloxacin, nalidixic acid, cefixime, ampicillin, tetracycline, trimethoprim-sulfamethoxazole, and erythromycin. The following organisms were used as quality control strains for MIC E-testing; Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 29213), and Pseudomonas aeruginosa (ATCC 27853). Results of susceptibility testing showed complete sensitivity to ciprofloxacin, cefixime and amplicillin for both isolated Inaba and Ogawa serotypes except all isolated Inaba serotypes from year 2011, which were resistant to cefixime. These resistant Inaba serotypes were not isolated in the next year. Inaba serotypes showed an increased resistance rate of up to 100% to nalidixic acid, tetracycline and trimethoprim-sulfamethaxazone, while Ogawa serotypes were 100% sensitive at the end of year 2013. The susceptibility pattern of erytromycine was similar in these two types. Sensitivity to erythromycin was decreased in both Inaba and Ogawa serotypes. The analyzed results indicate that tetracycline should not be considered as a first line antibiotic therapy for patients infected with Ogawa serotypes. Also, national guidelines for confirmation of cholera should be improved by responsible authorities to cover new resistance during outbreaks.

There are several protocols to extract DNA from Lactobacillus spp. In the case of L. casei it is harder because of its especial and thick cell wall. In this study, nine DNA extraction protocols (by lysozyme treatment) were evaluated and compared in two categories (traditional and kit-based protocols) and an improved method was presented. DNA quantity and quality was determined by spectrophotometry, agarose gel electrophoresis and polymerase chain reaction (PCR). The results revealed that the yield of extracted DNA differed by each protocol (5.8 - 17.1 μg/100 μL), but provided appropriate DNA for PCR amplification. The modified protocol offered the best total DNA extraction method when both quality (DNA purity; 1.54 μg) and quantity (DNA yield; 17.1 μg) were considered. We suggest this protocol for effective and inexpensive DNA isolation from L. casei for downstream biological processes such as PCR.

Infectious diarrhea is one of the most frequent diseases among children, especially in developing countries. The aim of this study was to determine the etiological agents and drug resistance patterns of common enteric pathogens isolated in an Iranian 1000-bed tertiary care hospital.Patients and In a retrospective study, we analyzed the etiology and drug resistance patterns of enteric pathogens associated with diarrheal cases. The study was carried out in the Milad hospital of Tehran over two years, from April of 2012 to January of 2014. Stool specimens from patients with diarrhea (n = 7321) were examined for enteric pathogens using routine microbiological culture methods. Strains of Salmonella, Shigella, and enteric pathogenic E. coli (EPEC) were serotyped and their susceptibility to commonly used antimicrobial agents was determined by a disk diffusion method, as recommended by the clinical and laboratory standards institute (CLSI) guidelines. Enteric pathogens were isolated from 310 (4.23%) of the patients. The most frequently isolated microorganisms included enteropathogenic E. coli (EPEC), Salmonella, and Shigella spp. The majority of the isolates of EPEC were resistant to commonly used antibiotics such as ampicillin (85.61%), cefixime (79.41%), and nalidixic acid. Resistance among other enteric pathogens was also prevalent. About 45.70% of the Salmonella isolates were resistant to chloramphenicol, and 87.95% were resistant to sulfamethoxazole/trimethoprim. Resistance of the Shigella isolates to nalidixic acid in comparison to the resistance recorded in previous studies was higher. The results show that enteric bacteria, including EPEC, Salmonella spp., and Shigella spp. are the major causative agents of diarrhea in the hospital. The emergence of antimicrobial resistance among enteric pathogens is an important problem for public health. Considering the threat of emerging antimicrobial resistance among enteric pathogens, a better surveillance system is necessary.

Coxiella burnetii is an important intracellular pathogen that ruminants can act as primary reservoirs. Reservoirs may excrete the bacterium into the placenta, vaginal mucus and feces. The aim of this study was to detect C. burnetii in aborted samples from ruminant flocks in Mashhad city, northeast of Iran, using the polymerase chain reaction (PCR) assay. A total number of 154 fetal tissue samples of cattle, sheep and goat were subjected to nested PCR assay. Sixteen (17.3%) out of 92 samples from sheep and 15 (25%) from 60 cattle fetuses were positive. The results of this study indicate the presence of C. burnetii in aborted ruminants and these can be the potential reservoirs of C. burnetii in the mentioned area.

The Fasciola trematodes are the most common liver flukes, living in a range of animals with global distribution and resulting in profound economic loss and public health challenges. Previous studies have indicated that the sequences of the second internal transcribed spacer (ITS-2) of ribosomal DNA (rDNA) provide reliable genetic markers for molecular systemic studies of Fasciola. The objective of the present study was to characterize Fasciola samples from different geographical regions of Sistan and Balouchestan province using sequences of second internal transcribed spacer (ITS-2) of ribosomal DNA (rDNA). Twenty adult trematodes were collected from the livers of slaughtered infected cattle. Total genomic DNA was extracted and ITS-2 rDNA targets were amplified by polymerase chain reaction (PCR). All samples were sequenced and investigated using the ClustalW2 sequence alignment tool and MEGA software. The sequences of some Iranian and non-Iranian isolates were used for comparison, in order to evaluate the variation in sequence homology between geographically different trematode populations. The results of comparing the ITS-2 sequences with the BLAST GenBank database showed one type of sequence for F. hepatica and three different types of sequences for F. gigantica in the specimens. The present study demonstrated that Fasciola samples from cattle in two geographical locations in Sistan and Balouchestan province represented no genetic diversity in F. hepatica and high genetic variation in F. gigantica.

One of the most common causes of chronic bacterial infections is H. pylori and there is evidence indicative of its strong association with gastric cancer. We aimed to determine the prevalence of H. pylori infection using Gram staining, IgG, urea breath test (UBT), and stool antigen from patients with gastrointestinal (GI) symptoms. Patients with GI symptoms who were referred to Fardis Central Laboratory, Fardis, Iran for identification of H. pylori from different clinical specimens from 2011 to 2014 were included in this study. Demographic data were retrieved from the medical records of enrolled patients. A total of 16002 patients were referred to Fardis Central Laboratory, Fardis, Iran over the past 3 years. Among them, 5662 (35.38%) were males and 10340 (64.62%) females; their mean age was 48 years (range 3 to 93 years). Of 16002 patients tested, 6770 (83.77%), 137 (1.69%), and 1174 (14.54%) were positive for H. pylori according to the results of immunoglobulin G (IgG), urea breath test (UBT), and H antigen, respectively. H. pylori infection rate in patients referring to Fardis Lab with GI symptoms was relatively high which could be due to some health habits. Although this kind of infection is considerably common, it can easily be diagnosed by noninvasive tests.