The effect of thyme essential oil and endothelial progenitor stem cells on lipopolysaccharide-induced sepsis in C57BL/6 mice

Sepsis is a potentially fatal syndrome related to severe systemic inflammation developed by infection. Despite different antimicrobial therapies, morbidity and mortality rates remain high. Herbs along with cell therapy have been introduced as a promising option to improve the symptoms of sepsis. The present study aimed to evaluate the therapeutic effect of simultaneous administration of thyme essential oil (TEO) and endothelial progenitor stem cells (EPCs) on lipopolysaccharide (LPS)-induced sepsis in C57BL/6 mice. Sepsis was induced in C57Bl/6J mice by intraperitoneal injection of LPS, followed 2 h later by an intravenous injection of EPCs or oral administration of TEO or simultaneous administration of TEO and EPCs. After 10 days, the complete blood cell, renal and liver factors, serum levels of inflammatory cytokines, and angiogenic factors were measured. Simultaneous treatment with EPCs and TEO significantly increased the survival of mice with sepsis and modulated the inflammatory response by reducing the serum levels of pro-inflammatory cytokines. Moreover, this treatment significantly reduced the level of white blood cells and neutrophils and increased the number of red blood cells, the percentage of hematocrit, and hemoglobin. The combination of TEO with EPCs decreased organ injuries and was assessed by lower levels of the liver enzymes alanine aminotransferase and aspartate aminotransferase compared to the sepsis group. Administration of EPCs and TEO also significantly improved angiogenic factors, lung function, and toll-like receptor 4 expression. EPCs in combination with TEO increase survival in the LPS-induced sepsis mice model by acting on several targets. Thus, the combination of TEO with EPCs can be a feasible approach for the future clinical treatment and control of sepsis.

Biofilm formation, antimicrobial resistance genes, and genetic diversity of Salmonella enterica subspecies enterica serotype Enteritidis isolated from food and animal sources in Iran

OBJECTIVES

Salmonella enterica serovar Entritidis is an important pathogen in foodborne diseases and causes gastroenteritis. Several studies have investigated the genetic diversity of the strains of this bacterium. However, our knowledge of the discriminatory power of the molecular methods is limited.

METHODS

In total, 34 strains of S. enteritidis were isolated from food related to animals. Antibiotic resistance of the strains, antibiotic resistance genes, and biofilm formation capacity of the strains were evaluated. For the genetic analysis of the strains, PFGE was performed using AvrII restriction enzyme.

RESULTS

Among the tested antibiotics, cefuroxime, nalidixic acid, and ciprofloxacin showed the highest resistance rates (79.4%, 47%, and 44.2%, respectively). Only three antibiotic-resistance genes were identified in these strains (blaTEM: 67.6%, tetA: 9%, and sul2: 3%). In total, 91% of the strains were biofilm producers. Clustering of strains using AvrII for 26 samples with the same XbaI PFGE profile showed that these strains were in one clone and had high homogeneity.

CONCLUSIONS

In conclusion, it is better to use a combination of several typing methods for typing strains that are genetically very close so that the results are reliable.

Staphylococcus aureus dormancy: waiting for insurgency

Relapse infection usually results from resistance to the antibiotic, acquired genes, or persister cells. Persister cells are formed through mutation, reduced activity or metabolically inactive pathways induced by antibiotics, harassing conditions, low ATP, and malnutrition. These factors provide the ground for bacteria to grow slowly. Such a slow growth rate makes traditional antibiotics ineffective against persister cells. Staphylococcus aureus (S. aureus), in addition to this form, can be observed in Small Colony Variants (SCVs), L-forms, and dormant, all of which are characterized by at least one feature, i.e., slow growth. Despite their slow growth, they are metabolically active in terms of stringent SOS and cell wall stress responses. The stress response involves resistance against harassing conditions, and it survives until it is reactivated later. The present study aims to discuss the mechanisms of all persister cell formations, circumstances involved, gene mutation, and adoptable strategies against it.

Prevalence and Characteristics of Yersinia Enterocolitica and Yersinia Pseudotuberculosis from Raw Milk Supplied in Tehran

Background: Foodborne diseases are caused by eating contaminated food. Yersinia species are among the bacteria involved in food contamination, such as meat, poultry, vegetables, and milk. This study aims to investigate the prevalence and characteristics of Yersinia enterocolitica and Yersinia pseudotuberculosis from raw milk in Tehran. Methods: In this study, 360 samples of raw milk were collected from farms around Tehran and examined according to the FDA method. Then, 25 ml of milk samples were added to 225 ml of Peptone Sorbitol Bile Broth and kept for 10 days at 4 °C for enrichment. After 10 days, 0.5 ml of the sample was added to 0.5 ml of 0.72% KOH solution and 0.54% NaCl. After 30 sec, it was cultured in the selected Cefsulodin-Irgasan-Novobiocin agar (CINagar) medium to remove the normal flora. The plates were stored for 48 h at 28 °C. The suspected Bull's eye colonies were purified and phenotyping tests were carried out on the selected colony. The 20 E API kits were used for confirming identification. Results: From 360 raw milk samples, 4 Yersinia isolates (1.1%) including one Y. pseudotuberculosis (0.27%) and three Y. enterocolitica (0.83%) were isolated. In addition to Yersinia, other bacteria such as Klebsiella, Serratia, Citrobacter, and Providencia were isolated from milk samples. Conclusion: The findings showed that clean tap water and healthy cattle in livestock can be effective in preventing Yersinia contamination. Lack of personal and environmental hygiene could cause food contamination by Yersinia and other intestinal bacteria leading to gastrointestinal infections.

NEBL and AKT1 maybe new targets to eliminate the colorectal cancer cells resistance to oncolytic effect of vesicular stomatitis virus M-protein

This study compares the oncolytic effect of vesicular stomatitis virus (VSV) wild type and M51R M-protein on the colorectal tumors of different invasive intensity on SW480 and HCT116 cell lines and 114 fresh colorectal cancer primary cell cultures. Fresh tumor samples were divided into two groups of lower stages (I/II) and higher stages (III/IV) regarding the medical records. The presence of two mutations in the PIK3CA gene and the expression of NEBL and AKT1 genes were evaluated. The cells were transfected with a plasmid encoding VSV wild-type and M51R mutant M-protein. Results showed either wild type or M51R mutant can kill SW480 and stage I/II primary cultures while mutant M-protein had no apoptotic effects on HCT116 cells and stage III/IV primary cultures. NEBL and AKT1 expression were significantly higher in resistant cells. Elevated caspase-9 activity confirmed that the intrinsic apoptosis pathway is the reason for cell death in lower-stage cells. Different tumors from the same cancer exhibit different treatment sensitivity due to genetic difference. NEBL and AKT1 gene expression may be responsible for this difference, which may be the target of future investigations. Therefore, tumor staging should be considered in oncolytic viral treatment as an interfering factor.

Molecular identification of aflatoxigenic Aspergillus species in dried nuts and grains collected from Tehran, Iran

INTRODUCTION

Agricultural commodities contaminated by molds and mycotoxins can be considered as public health problems in less developed countries, particularly in Iran. Hence the main purpose of this study was to identify mold fungi and molecular analysis of the most important species of aflatoxin-B1-producing Aspergillus species in some dried nuts and grains in local markets in Tehran.

MATERIALS AND METHODS

Two hundred fifty samples of wheat, rice, corn, pistachios, and peanuts were collected from the five different locations of Tehran between January 2018 and January 2019. The samples were analyzed by using direct seed inoculation method and grain crushing method. Fungal strains were identified as Aspergillus spp. on the basis of morphological characters and further confirmed by using of β-tubulin gene sequencing. To differentiate between aflatoxigenic and non-aflatoxigenic Aspergillus spp., the isolates were screened for the presence of aflatoxigenic genes (nor-1, ver-1, omtA, and aflR).

RESULTS

One-handed forty-eight aflatoxigenic Aspergillus isolates (144 A. flavus and 4 A. parasiticus) were identified and aflR gene was the most frequent gene in these species. Five isolates (4 A. flavus, 1 A. parasiticus) had quadruplet pattern, 64 isolates (63 A. flavus, 1 A. parasiticus) had more than 1 gene and 39 isolates (38 A. flavus,1 A. parasiticus) did not have any genes.

CONCLUSION

According to the contamination of dried nuts and grains by some aflatoxigenic fungi, an extensive surveillance is necessary to provide a wider view on these products. Moreover, effective and efficient aflatoxin control program requires identifying and managing key elements that are effective in reducing mycotoxin production at farm level or in storage conditions.

Correction to: Molecular identification of aflatoxigenic Aspergillus species in dried nuts and grains collected from Tehran, Iran

[This corrects the article DOI: 10.1007/s40201-021-00734-6.].

Amniotic Membrane Transplantation for Persistent Epithelial Defects and Ulceration due to Pseudomonas Keratitis in a Rabbit Model

Purpose

The use of amniotic membrane has been suggested in the treatment of infectious keratitis for its intrinsic anti-infective properties probably mediated by its anti-inflammatory effects. The aim of this study was to investigate the effect of amniotic membrane transplantation (AMT) along with ciprofloxacin to cure the primary stages of Pseudomonas keratitis.

Methods

In total, 28 rabbits were selected and divided in four groups as follows: group 1 as control, group 2 with amniotic membrane, group 3 with ciprofloxacin, and group 4 with amniotic membrane combined with ciprofloxacin. About 0.05 cc suspension of Pseudomonasaeruginosa, 27853 ATCC was injected into corneal stroma.

Results

The results showed groups of AMT, AMT + ciprofloxacin, and ciprofloxacin had 0% perforation while the control group had 85.6%. Average infiltration of 5.5 mm was observed in ciprofloxacin group, 5 mm in AMT + ciprofloxacin group, 24 mm in AMT group, and finally 23.75 mm for control. Amniotic membrane showed to be effective in prevention of cornea perforation as well as remission of Pseudomonas keratitis. There was no significant difference between ciprofloxacin groups in comparison with ciprofloxacin + AMT group. However, regarding the anti-inflammatory effect, the process of improvement of inflammation in ciprofloxacin + AMT group was faster.

Conclusion

Transplantation of amniotic membrane in the primary stages of Pseudomonas keratitis treatment remarkably prevents the disease and it can be used to control its process.

Antimicrobial resistance patterns, virulence gene profiles, and genetic diversity of Salmonella enterica serotype Enteritidis isolated from patients with gastroenteritis in various Iranian cities

Objectives

This study aimed to evaluate antibiotic resistance profiles and presence of virulence genes among Salmonella enterica serovar Enteritidis (S. Enteritidis) isolated from patients with gastroenteritis in various regions of Iran. Moreover, genetic relatedness among the strains was assessed by pulsed-field gel electrophoresis (PFGE).

Materials and Methods

From April through September 2017, 59 Salmonella strains were isolated from 2116 stool samples. Of these strains, 27 S. Enteritidis were recovered. These strains were subjected to disk diffusion tests, polymerase chain reaction (PCR) for detection of virulence genes (invA, hilA, pefA, rck, stn, ssrA, ssaR, sefA, spvC, sipA, sipC, sopB, sopE, and sopE2), and PFGE.

Results

High prevalence of resistance towards cefuroxime (n = 20, 74.1%) and ciprofloxacin (n = 13, 48.2%) were demonstrated. All tested strains possessed invA, hilA, sefA, sipA, sopB, and sopE. The least prevalent virulence gene was rck (n = 6; 22.2%). Based on combinations of virulence genes, 12 virulotypes were observed. The most common virulotype was VP2 (n = 12; 44.4%), harboring all of the virulence genes except for rck. PFGE typing showed only two distinct fingerprints among tested strains. Each fingerprint had completely different virulotypes. Notably, VP4 (harboring all genes except for rck and spvC) was only presented in pulsotype A, while VP2 was confined to pulsotype B.

Conclusion

S. Enteritidis strains were derived from a limited number of clones, suggesting that it is highly homogenous. Future works should consider combinations of other genotyping methods together with larger sample sizes from more diverse sources.

Staphylococcus aureus: biofilm formation and strategies against it

The formation of Staphylococcus aureus biofilm causes significant infections in the human body. Biofilm forms through the aggregation of bacterial species and brings about many complications. It mediates drug resistance and persistence and facilitates the recurrence of infection at the end of antimicrobial therapy. Biofilm formation goes through a series of steps to complete, and any interference in these steps can disrupt its formation. Such interference may occur at any stage of biofilm production, including attachment, monolayer formation, and accumulation. Interfering agents can act as quorum sensing inhibitors and interfere in the functionality of quorum sensing receptors, attachment inhibitors and affect the cell hydrophobicity. Among these inhibiting strategies, attachment inhibitors could serve as the best agents against biofilm formation. If pathogens abort the attachment, the following stages of biofilm formation, e.g., accumulation and dispersion, will fail to materialize. Inhibition at this stage leads to suppression of virulence factors and invasion. One of the best-known inhibitors is a chelator that collects metal, Fe+, Zn+, and magnesium critical for biofilm formation. These influential factors in the binding and formation of biofilm are investigated, and the coping strategy is discussed. This review examines the stages of biofilm formation and determines what factors interfere in the continuity of these steps. Finally, the inhibition strategies are investigated, reviewed, and discussed. Keywords: Biofilm, Staphylococcus, Biofilm inhibitor, Dispersion, Antibiofilm agent, EPS, PIA.

Antimicrobial Susceptibility, Serotyping, and Molecular Characterization of Antibiotic Resistance Genes in Listeria monocytogenes Isolated from Pregnant Women with a History of Abortion

Background:

Listeria monocytogenes show high mortality among pregnant women and newborns. This study aimed to detect L. monocytogenes in pregnant women with a history of abortion and assess the serotypes, antibiotic susceptibility patterns, and its resistance genes.

Methods:

Overall, 400 vaginal swabs were taken from pregnant women with a history of abortion in the past few years in a tertiary care hospital in Tehran, Iran, during 2015–2018. Antibiotics susceptibility to a panel of 10 antibiotics was determined using the standard disk diffusion method and the isolates serotyped by the agglutination method. The antimicrobial-resistant isolates were also screened for the presence of tetM, ermB and dfrD genes by PCR.

Results:

Overall, 22 L. monocytogenes isolates were identified. High rates of resistance were observed for trimethoprim (50%; n=11), sulphamethoxazole (50%; n=11), tetracycline (45.45%; n=10) and gentamicin (36.36%; n=8). From 22 L. monocytogenes isolates, 13 (59.10 %), 5 (22.73%), 3 (13.63%) and 1 (4.54%) belonged to serotypes 4b, 1/2a, 1/2b, and 3c, respectively. The genetic determinant tetM was detected in 70% of the tetracycline-resistant isolates. Out of 11 trimethoprim-resistant isolates, 27.27% isolates contained dfrD. Moreover, the ermB gene was found in 83.33% of the erythromycin-resistant isolates.

Conclusion:

Ampicillin and partly penicillin consider to be suitable antimicrobial agents to treat human listeriosis. Moreover, due to resistance against many antibiotics, it is necessary to continue monitoring and managing antimicrobial resistance.

Isolation, Identification, and Antibiotic Susceptibility Testing of Salmonella Isolated from Foodborne Outbreaks

Background: Foodborne diseases are a major problem worldwide. The epidemiological investigations in many parts of the world have shown an increase in infections caused by Salmonella serovars. Furthermore, the emergence of drug resistance among them has become a major global concern and awareness of the resistance patterns of Salmonella could be very useful in treatment of diseases. Objective: This study aimed to investigate Salmonella serotypes in foodborne outbreaks by sequencing of ITS region of 16S-23SrRNA gene and to determine their antimicrobial susceptibility pattern. Materials and Methods: A total of 614 diarrheal stool samples were collected from 173 foodborne outbreaks in different provinces of Iran during one year. Identification of Salmonella was carried out by phenotypic and molecular (16s-23srRNA gene detection) methods and antibiotic susceptibility was performed using disc diffusion method. Results: Out of 614 samples, 18 isolates were identified as Salmonella of which 16 (88.9%) isolates were Salmonella Enteritidis and 2 (11.1%) isolates as Salmonella Paratyphi A. All isolates were sensitive to ceftazidime, and high resistance was seen with nalidixic acid with 14 (77.8%) isolates. Conclusion: Increasing antibiotic resistance in many bacterial pathogens such as Salmonella has been a major threat for human health. Therefore, identifying the antibiotic resistance patterns of Salmonella serovars may help in treatment of the associated infections.

Associations between climatic parameters and the human salmonellosis in Yazd province, Iran

Salmonella is one of the most common causes of foodborne disease outbreaks in developing countries. Climatic factors such as temperature, rainfall, and relative humidity can directly increase the growth and spread of these pathogens. Therefore, the aim of this study was to investigate long-term temporal trends and seasonal patterns of Salmonella infections as well as evaluating the effects of demographic and climatic factors on the infection incidence in Yazd province, Iran during 2012-2015. The incidence of Salmonella infections was highest among patients with the age group of ≤5 years and peaked in summer, especially during June. Contrary to expectations, no significant associations were seen between the average monthly temperature, rainfall or humidity and incidence rate (IR) of salmonellosis. Interestingly, atmospheric dust hovering was significantly associated with an increased risk of salmonellosis. Transmission pathways of Salmonella spp. in communities should be considered as a complex ecological process that animal reservoirs, socio-economic factors, and lifestyle behaviors need to be addressed in future studies.

Antibacterial Effect of Zinc Oxide Nanoparticles on Standard Strains and Isolates of Pseudomonas Aeruginosa and Staphylococcus Aureus

Background: Studies have shown that metal nanoparticles are highly active and exhibits remarkable bactericidal activity against a wide range of bacteria. Objective: The aim of this study was to examine the antibacterial activity of zinc oxide nanoparticles against standard strains of Pseudomonas aeruginosa and Staphylococcus aureus and their isolates in food products. Methods: This experimental study was conducted on the two pathogenic bacteria and their two standard strains. Zinc oxide nanoparticles were prepared from zeolite and their amount was determined using the XRF analyzer. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were measured using disk diffusion method . Findings: The MIC value of zinc oxide nanoparticles was 4 mg/mL for standard strain and isolate of pseudomonas aeruginosa and 2 mg/mL for standard strain and isolate of staphylococcus aureus. The MBC values for standard strain and isolate of pseudomonas aeruginosa were 16 and 8 mg/mL, respectively, while for the standard strain and isolate of Staphylococcus aureus it was reported 8 mg/mL. Conclusion: Staphylococcus aureus is more sensitive to zinc oxide nanoparticles that pseudomonas aeruginosa.

Investigation of the Frequency of Foodborne Botulism in Patients Referred to Loghman Hospital in Tehran City, Iran, From 2008 to 2019

Background: Foodborne botulism is a fatal paralytic illness caused mainly by the neurotoxin produced by an anaerobic bacterium called Clostridium botulinum. In this study, the frequency of foodborne botulism in patients referred to a hospital in Iran has been reviewed for ten years.Methods: In this routine database study, medical records of patients with foodborne botulism referred to Loghman Hospital in Tehran City, Iran, from March 20, 2008, to March 20, 2019, were reviewed. Information on variables of age, sex, place of residence, food consumed, clinical symptoms of patients (such as dysphagia, nausea, vomiting, ataxia, etc.), toxin type, and length of hospitalization were collected with a researcher-made questionnaire. Finally, the collected data were analyzed in SPSS-24 with descriptive and analytical statistical tests.Results: In this study, 61 suspected botulism patients were clinically diagnosed in Loghman Hospital, of whom 55 patients were clinically suspected of foodborne botulism, 5 patients had iatrogenic botulism, and 1 patient had infant botulism. Of these 55 patients with the clinical diagnosis of foodborne botulism, 19 patients were confirmed by laboratory examinations, and 2 patients died. Sixteen patients confirmed by laboratory had neurotoxin botulinum type A. The mean age of the patients was 36.9 years with a standard deviation of 18.6 years. About 54.5% of the patients were male and 45.5% female. Weaknesses (58.2%), ptosis (droopy eyelid) (56.4%), and diplopia (double vision) (52.7%) were the common clinical symptoms of the patients under study. Canned foods and dairy products were the main foods consumed by the patients. The duration of admission time ranged between 1 and 41 days, with an average of 7.7 days. About 23.64% of patients were admitted to the intensive care unit.Conclusion: The prevalence of foodborne botulism is rare compared with other food poisonings but is still a major public health problem due to the consumption of traditional food products and unboiled canned foods in Iran.

Some probiotic properties of Lactobacillus species isolated from honey and their antimicrobial activity against foodborne pathogens

Lactobacilli commonly used as a probiotic and they can be isolated from various sources such as fermented foods and gastrointestinal tracts of humans and animals. The aims of this study were isolation and identification of lactobacilli from honey and investigation of some probiotic properties and antimicrobial effects against foodborne bacterial pathogens. A total of 88 honey samples were collected from different areas in Iran. About 1.00 g of each honey was cultured in de Man, Rogosa, and Sharpe (MRS) broth and then sub-cultured on MRS agar. The isolates were assessed for probiotic potentials such as tolerance to acid and bile. Then, antimicrobial activity of isolates against seven foodborne pathogens including Listeria monocytogenes, Shigellaflexneri, Staphylococcus aureus, Salmonellaenteritidis, Enteropathogenic Escherichiacoli, Escherichiacoli O157 H7 and Bacilluscereus was investigated. From 88 honey samples, 39 isolates were identified by 16S rDNA gene sequencing method. Fructophilic lactic acid bacteria (FLAB) with 29 (74.00%) isolates were dominant identified bacteria (27 L. kunkeei and two Fructobacillus fructosus). Also, four L. plantarum, two L. paracasei, one L. brevis, one L. rhamnosus, one L. casei and one L. fermentum were identified. Two L. kunkeei isolates and one F. fructosus isolate were resistant to acid and bile salt. Two L. rhamnosus isolates and one L. paracasei isolate inhibited all pathogens (100%). This is the first study in Iran that isolated lactobacilli from honey. The FLAB especially L. kunkeei were isolated as dominated species from honey. Some lactobacilli isolates have probiotic potential and may be useful for the prevention and treatment of infections, but more investigations are needed.

Antimicrobial investigation on the multi-state outbreak of salmonellosis and shigellosis in Iran

Background: Foodborne diseases are caused by indigestion of contaminated food. In some cases they may result in either hospitalization or death. The Centers for Disease Control (CDC) and Prevention in 2017 stated that 10% reduction in foodborne illness would prevent nearly five million illnesses every year. Approximately one out of six Americans become ill from contaminated foods or beverages every year. Another problem is drug resistance which is responsible for approximately 2 million illnesses and around 23000 dead every year. Nearly 400,000 Americans acquire antibiotic-resistant Salmonella or Campylobacter each year. The aim of this study was to evaluate the outbreak of salmonellosis and shigellosis along with their antibiotic susceptibility patterns in different provinces of Iran.

Methods: Over a period of 2 years from 2015 to 2016, a total of 1055 cases in 249 outbreaks reported in 20 provinces of Iran, as a part of surveillance by the National Institute of Health (NIH). The stool samples of patients were taken and tested for Salmonella spp. and Shigella spp. by conventional standard techniques. Disk diffusion was used for the antibiotic sensitivity test.

Results: Of 1055 cases, 118 (11.2%) contained Shigella and 74 (7%) contained Salmonella. Antibiotic susceptibility tests showed that entirely 100% of Salmonella and Shigella isolates were susceptible to ciprofloxacin; whereas 12.2% of Salmonella and 98.2% of Shigella were resistant to cotrimoxazole.

Conclusion: Our results show that there is a need for more food handling practices to minimize the exposure of consumers to Salmonella and Shigella , at all points along the distribution chain.

Molecular Mechanisms of Salmonella Effector Proteins: A Comprehensive Review

Salmonella can be categorized into many serotypes, which are specific to known hosts or broadhosts. It makes no difference which one of the serotypes would penetrate the gastrointestinal tract because they all face similar obstacles such as mucus and microbiome. However, following their penetration, some species remain in the gastrointestinal tract; yet, others spread to another organ like gallbladder. Salmonella is required to alter the immune response to sustain its intracellular life. Changing the host response requires particular effector proteins and vehicles to translocate them. To this end, a categorized gene called Salmonella pathogenicity island (SPI) was developed; genes like Salmonella pathogenicity island encode aggressive or modulating proteins. Initially, Salmonella needs to be attached and stabilized via adhesin factor, without which no further steps can be taken. In this review, an attempt has been made to elaborate on each factor attached to the host cell or to modulating and aggressive proteins that evade immune systems. This review includes four sections: (A) attachment factors or T3SS- independent entrance, (B) effector proteins or T3SS-dependent entrance, (c) regulation of invasive genes, and (D) regulation of immune responses.

Phage Therapy as an Approach to Control Salmonella enterica serotype Enteritidis Infection in Mice

INTRODUCTION

Salmonella enterica serotype Enteritidis (S. Enteritidis) is a cause of food-borne human illness. Given the prevalence of antibiotic resistance of Salmonella Enteritidis and the lack of antibiotic efficacy in future years, its replacement with other agents is necessary. One of the most useful agents is bacteriophages.

METHODS

S. Enteritidis was identified using a multiplex polymerase chain reaction assay. The effective bacteriophages were isolated from hospital wastewater samples. The effects of the bacteriophages were evaluated both in vitro and in vivo.

RESULTS

The phage SE20 belonged to the Podoviridae family, and the genome size was 40 kb. The evaluation of phage SE20 at variable pH ranges showed its susceptibility to pH < 3 and pH > 12. The animal model showed that mice infected with S. Enteritidis developed hepatomegaly and splenomegaly, but did not experience gastrointestinal complications after receiving the bacteriophages.

CONCLUSIONS

The results of this study suggest that phage SE20 is a promising candidate for controlling salmonellosis caused by Salmonella Enteritidis.

Antimicrobial Resistance and Presence of Class 1 Integrons Among Different Serotypes of Salmonella spp. Recovered From Children with Diarrhea in Tehran, Iran

BACKGROUND

Salmonellosis is a major food-borne disease worldwide. The increasing prevalence of antimicrobial resistance among food-borne pathogens such as Salmonella spp. is concerning.

OBJECTIVE

The main objective of this study is to identify class 1 integron genes and to determine antibiotic resistance patterns among Salmonella isolates from children with diarrhea.

METHODS

A total of 30 Salmonella isolates were recovered from children with diarrhea. The isolates were characterized for antimicrobial susceptibility and screened for the presence of class 1 integron genes (i.e. intI1, sulI1, and qacEΔ1).

RESULTS

The most prevalent serotype was Enteritidis 36.7%, followed by Paratyphi C (30%), and Typhimurium (16.7%). The highest rates of antibiotic resistance were obtained for nalidixic acid (53.3%), followed by streptomycin (40%), and tetracycline (36.7%). Regarding class 1 integrons, 36.7%, 26.7%, and 33.3% of the isolates carried intI1, SulI, and qacEΔ1, respectively, most of which (81.8%) were multidrug-resistant (MDR). Statistical analysis revealed that the presence of class 1 integron was significantly associated with resistance to streptomycin and tetracycline (p = 0.042). However, there was no association between class 1 integron and other antibiotics used in this study (p > 0.05).

CONCLUSION

The high frequency of integron class 1 gene in MDR Salmonella strains indicates that these mobile genetic elements are versatile among different Salmonella serotypes, and associated with reduced susceptibility to many antimicrobials.

Study of VanA, B, C, D, E Genes in Vancomycin Resistant Enterococci Isolated from Retailed Dried Vegetables in Tehran, Iran

Background: Enterococcus spp. are resistant to many antimicrobials including vancomycin. They may be found in foods and water. Objective: In the current study, van genes were investigated in vancomycin resistant enterococci (VRE) isolated from dried vegetables in Tehran, Iran. Materials and Methods: In this study, 140 dried vegetable samples were collected from local retailers in Tehran, Iran, 2015. Bacteria were isolated using culture, biochemistry and molecular methods. Susceptibility of the enterococcal isolates was assessed to six antibiotics of ampicillin, chloramphenicol, erythromycin, gentamicin, tetracycline and vancomycin using Kirby-Bauer method. The prevalence of vanA, B, C, D, E genes was molecularly studied in VRE using polymerase chain reaction (PCR) and sequencing techniques. Results: Of 140 dried vegetable samples, Enterococcus spp. strains were isolated from 84 samples (60%). Totally, 48% of the isolates were resistant to vancomycin. Of 41 vancomycinresistant enterococcal isolates, vanA was found in 23 (56.1%), vanB in 8 (19.5%) and vanC in 2 (4.9%) isolates. No vanD or vanE was found in the isolates. Results have shown a high rate of contamination with Enterococcus spp., especially VRE, in dried vegetables in Tehran. Conclusion: Therefore, further hygienic regulations such as personal training and food processing, transportation, storage and marketing must be routine in food industries and local retailers.

The Immunomodulatory Role of G2013 (α-L-Guluronic Acid) on the Expression of TLR2 and TLR4 in HT29 cell line

BACKGROUND

The non-steroidal anti-inflammatory drugs (NSAIDs) play crucial role in the controlling of inflammatory diseases. Due to the vast side effects of NSAIDs, its use is limited. G2013 or α-L-Guluronic Acid is a new NSAID with immunomodulatory features.

OBJECTIVES

Considering the leading role of TLRs in inflammatory responses, in this study, we aimed to evaluate G2013 cytotoxicity and its effect on the expression of TLR2 and TLR4 molecules.

METHODS

HEK293-TLR2 and HEK293-TLR4 cells were cultured and seeded on 96-well cell plate, and MTT assay was performed for detecting the viability of the cells after treatment with different concentrations of G2013. HT29 cells were grown and treated with low and high doses of G2013. After total RNA extraction and cDNA synthesis, quantitative real-time PCR were performed to assess the TLR2 and TLR4 mRNA synthesis.

RESULTS

We found that concentrations of ≤125 µg/ml of G2013 had no apparent cytotoxicity effect on the HEK293-TLR2 and -TLR4 cells. Our results indicated that after G2013 treatment (5 µg/ml) in HT29 cells, TLR2 and TLR4 mRNA expression decreased significantly compared with the untreated control group (p=0.02 and p=0.001 respectively).

CONCLUSION

The results of this study revealed that G2013 can down regulate the TLR2 and TLR4 gene expression and exerts its inhibitory effect. Our findings are parallel to our previous finding which showed G2013 ability to down regulate the signaling pathway of TLRs. However, further studies are needed to identify the molecular mechanism of G2013.

Molecular epidemiology and genetic characterization of Shigella in pediatric patients in Iran

Infection with Shigella is considered a major cause of morbidity and mortality in children with diarrhea in developing countries, especially in Iran. Due to the importance of country-level epidemiological data, molecular characterization of genetic determinants of Shigella spp. is a necessity. The aim of the present study was to investigate the prevalence of integron types, bla-CTX-M, bla-SHV and blaTEM β-lactamase genes of Shigella isolates in pediatric patients in Tehran, Iran. In a time period of 18 months from May 2015 to August 2017, 75 Shigella spp. were isolated from non-duplicative diarrheal stool specimens in six different hospitals in Tehran. The isolates from patients were further analyzed for their antibiotic susceptibility and extended-spectrum beta-lactamase (ESBL) production. Polymerase chain reaction was performed for amplification of the integrons (I, II, III), TEM, SHV, CTX-M15. The prevalence of S. sonnei, S. flexneri, S. dysenteriae and S. boydii were 40 (53.3%), 33 (44%), 1 (1.3%) and 1 (1.3%), respectively. The results of an antimicrobial resistance test showed that the high percentage of resistance to nalidixic acid (NA), ampicillin (AMP) and trimethoprim/sulfamethoxazole (SXT) included 38 (50.6%), 59 (81.3%) and 64 (88%) isolates, respectively. Further results revealed that 52% and 76% of Shigella isolates carried intI and intII genes, respectively. In this study, the rates of CTX-M (10.7%), SHV (28%) and TEM (21.3%) were determined, all of which were positive for blaCTX-M15. This study showed the high prevalence of multidrug resistant S. sonnei and S. flexneri. Furthermore, it highlighted the increasing integrons (intI and intII) and ESBL genes, especially blaCTX-M15, in Shigella isolates.

Campylobacter Concisus and Its Effect on the Expression of CDX1 and COX2

Background: Barrett’s oesophagus (BO) is a pre-malignant condition in which normal squamous epithelium of the lower oesophagus and gastresophageal junction is replaced by columnar cells and progress to oesophageal adenocarcinoma. The increase burden of oesophagus cancer morbidity and mortality worldwide make study of factors involved in the pathogenesis of BO essential. However, most of studies that examine the environmental risk factors associated with increased incidence and prevalence of BO have largely ignored the potential role of bacteria in disease aetiology. Aims: This study examined the role of Campylobacter concisus isolated from Barrett’s and adenocarcinoma patient samples as one of possible environmental factors in the progression of Barrett’s oesophagus to oesophagus adenocarcinoma. Methods: We focused on the effect of C. concisus on the expression caudal type homeobox 1 gene (CDX1) and cyclooxygenase-2 (COX-2) in three BO cell lines using quantitative real-time PCR. In addition, the attachment and invasion characteristics of C. concisus were also tested. Results: Results showed that C. concisus had a strong attachment to the cell lines and induce the expression of CDX1 in Barrett’s cell lines in a time-dependent manner. Conclusion: Findings indicate that C. concisus could be as a new challenge in the progression of BO to adenocarcinoma.

Prevalence, antimicrobial susceptibility, serotyping and virulence genes screening of Listeria monocytogenes strains at a tertiary care hospital in Tehran, Iran

BACKGROUND AND OBJECTIVES

Listeria monocytogenes is the etiological agent of listeriosis, a highly fatal infection which causes miscarriage or stillbirth in pregnant women. The objective of this study was to detect the prevalence, serotypes, antimicrobial susceptibility and virulence factors of L. monocytogenes isolated from pregnant women with vaginitis at a tertiary care hospital in Tehran, Iran.

MATERIALS AND METHODS

During September 2015 to February 2017, a total of 400 vaginal swabs were collected from pregnant women. The presumptive isolates were characterized biochemically. All L. monocytogenes isolates were further analyzed by serotyping and antimicrobial susceptibility tests. All positive samples for L. monocytogenes were analyzed for presence of virulence genes (hlyA, actA, inlA, inlC, inlJ and prfA).

RESULTS

Twenty-two (5.5%) of the samples were found positive for presence of L. monocytogenes. Most isolates are resistant to trimethoprim/sulfamethoxazole (81.82%) and chloramphenicol (54.55%). The majority of tested isolates (59.10%) belonged to serotype 4b, followed by 1/2a (22.73%), 1/2b (13.63%), and 3c (4.54%). The hlyA, actA and inlA were detected in all of the 22 L. monocytogenes isolates, but two, three and five isolates were found to lack inlC, inlJ and prfA, respectively. Only one isolate lacked three inlC, inlJ and prfA genes, and two isolates simultaneously lacked both inlJ and prfA genes.

CONCLUSION

Evaluation of virulence factors and antimicrobial susceptibility can be highly helpful to develop effective treatment strategies against L. monocytogenes infections. This study is noteworthy in that it documents prevalence, virulence characteristics, and antimicrobial resistance of L. monocytogenes.

Molecular analysis of integrons and antimicrobial resistance profile in Shigella spp. isolated from acute pediatric diarrhea patients

Introduction:Shigella spp. is a growing global health concern due to increasing multiple drug resistance, commonly resulting in therapeutic failure. Integrons are gene expression systems run by integrase genes. The aims of this study were detection of class I, II and III integrons and assessment of antimicrobial resistance in Shigella spp. isolated from acute pediatric diarrhea patients. Materials and methods: From January to December 2015, 16 Shigella spp. were isolated from 310 non-duplicative diarrheal stool samples in Children's Medical Center, Tehran, Iran. The isolates were analyzed for their antibiotic susceptibility using CLSI guidelines M100-S14. Multiplex PCR was used for amplification of I, II and III integron-associated integrase (intl) genes. Results: Of 310 stool samples, 16 (5.2%) were positive for Shigella spp., in 7 of them S. sonnei and in 9 of them S. flexneri were identified. Results of the antimicrobial susceptibility test showed that 6.2%, 50%, 31.2%, 6.2%, 81.2%, 56.2% and 31.2% of the isolates were resistant to gentamicin, chloramphenicol, nalidixic acid, ciprofloxacin, tetracycline, ampicillin and trimethoprim-sulfamethoxazole, respectively. Multiplex PCR results revealed that 6.2% (1/16), 31.2% (5/16), 50% (8/16) of Shigella isolates carried intlI, intlII and both intlI/intllI genes. No class 3 integrons were detected. Discussion: In this study, multidrug resistance was seen in Shigella isolates similar to that in isolates from other geographical areas. This is possible due to inappropriate use of antimicrobials. Furthermore, prevalence of multidrug resistance was significantly linked to the presence of integrin genes. Conclusion: A class 2 integron plays a role in presence of multidrug resistance in Shigella spp. It is vital to prevent the spread of antibiotic resistance through continuous monitoring.

Frequency of Mutations in Quinolone Resistance-Determining Regions and Plasmid-Mediated Quinolone Resistance in Shigella Isolates Recovered from Pediatric Patients in Tehran, Iran: An Overlooked Problem

Fluoroquinolone (FQ) resistance in clinical isolates of Shigella species has been increasing reported in recent years. This study was carried out to find the mutations within the quinolone resistance-determining regions (QRDRs) and the prevalence of plasmid-mediated quinolone resistance (PMQR) determinants among the clinical isolates of Shigella sp. in Tehran, Iran. A total of 50 Shigella isolates were collected from five teaching therapeutic centers in Tehran, Iran and analyzed for antibiotic susceptibility over a period of 20 months from July 2015 to January 2017. The PCR and direct nucleotide sequencing were used for genetic alterations in the QRDRs. The PMQR genes were detected using PCR. The results revealed four types of mutations in the QRDR of gyrA: 20 (40%) had a S83L mutation, 1 (2%) had a S83A mutation, 2 (4%) had a D87G mutation, and 1 (2%) isolate had a D87Y mutation. Mutations were also found at codon N57D, D200N, and E210K in three isolates. Seven hospitalized children had qnrS determinants, and one isolates had the mutation S83A, while two isolates had double mutations at S83L and/or D87G (Ser83Leu and Asp-87Gly). The PMQR gene-positive isolates had the single replacement of serine with leucine. In hospitalized children, two isolates had two types of PMQR determinants (qnrS and qnrA) and (qnrS and qnrB) at once. The results of this study indicate that the emergence of strains with mutations in the QRDR regions and the capture of PMQR determinants in strains may lead to failure in therapy with FQ and the widespread emergence of strains with high-level FQ resistance.

Antimicrobial resistance, virulence genes and genetic relatedness of Salmonella enterica serotype Enteritidis isolates recovered from human gastroenteritis in Tehran, Iran

OBJECTIVES

Salmonella enterica serotype Enteritidis is a major serotype associated with human salmonellosis. The main objective of this study was to determine the antibiotic susceptibility patterns and the presence of virulence-associated genes among S. Enteritidis strains isolated from patients with gastroenteritis in Tehran, Iran.

METHODS

Over a period of 14 months (May 2015 to July 2016), 44 S. Enteritidis isolates recovered from clinical sources were characterised for antimicrobial susceptibility and virulence genes. Possible genetic relatedness among the strains was also assessed using pulsed-field gel electrophoresis (PFGE).

RESULTS

Salmonella Enteritidis isolates showed high rates of resistance to ciprofloxacin (90.9%) and nalidixic acid (77.3%). Of the 44 S. Enteritidis isolates, 30 (68.2%) were resistant to three or more antibiotics. Twenty-two different antimicrobial resistance patterns were detected among the isolates. The most frequent resistance type was antibiotype 14 (resistance to ciprofloxacin, cefuroxime and nalidixic acid), occurring in 8 (18.2%) of the isolates. Notably, all of the isolates carried invA, sefA, sipA and sopE2 virulence genes. Furthermore, 17 virulence profiles were observed among the strains. The most common virulence profile was VP1 (n=17; 38.6%), harbouring all of the virulence genes. Two distinct PFGE patterns were observed among 44S. Enteritidis isolates. There was no association between virulence profiles or antibiotypes and PFGE clusters.

CONCLUSIONS

Overall, this study provides valuable information on the virulence gene content, antibiotic resistance and genetic diversity of S. Enteritidis isolated from human sources in Iran.

Bifidobacterium animalis in combination with human origin of Lactobacillus plantarum ameliorate neuroinflammation in experimental model of multiple sclerosis by altering CD4+ T cell subset balance

BACKGROUND

Multiple Sclerosis (MS) is a chronic inflammatory autoimmune disease of the central nervous system (CNS). Recent reports have shown that probiotics can induce immunomodulatory activity with promising effects in inflammatory diseases. This study was designed to reveal the molecular and cellular mechanisms underlying the effect of Lactobacillus plantarum A7, which comprises human commensal bacteria, and Bifidobacterium animalis, a potential probiotic strain, on alleviation of experimental autoimmune encephalomyelitis (EAE), an animal model of MS.

METHODS

To evaluate the therapeutic effects of probiotic strains, female C57BL/6 mice (8-10 wks old) received Lactobacillus plantarum A7, Bifidobacterium animalis PTCC 1631or a mixture of both strains through oral administration daily for 22days beginning simultaneous with induction of EAE. The clinical parameters were recorded daily. On Day 22, each mouse was bled, and their spinal cord was removed for histology analysis. The effects of the treatments on regulatory T (Treg) cells level were evaluated using flow cytometry, and T-cell proliferation was assessed using a BrdU incorporation assay. The supernatants of spleen and lymph nodes cultured and mononuclear cells were collected for quantification of different panel of pro and anti-inflammatory cytokines by ELISA. The analysis of gene expression was performed at RNA level for transcription factors by real-time PCR.

RESULTS

The results showed that treatment with a mixture of the two strains caused a more significant delay in the time of disease onset and clinical score compared to when the strains were used alone. The pathological features of the disease, such as mononuclear infiltration into the CNS, were also inhibited more significantly by the combinational approach. The results also revealed that treatment with combination of both strains enhanced the population of CD4⁺CD25⁺Foxp3⁺-expressing T-cells in the lymph nodes and the spleen.

TREATMENT

with our probiotic strains markedly inhibited disease associated cytokines while increased anti-inflammatory cytokines. Additionally, L. plantarumA7 and B. animalis ameliorated EAE condition by favoring Th2 and Treg differentiation via up-regulation of Foxp3 and GATA3 in the brain and spleen as well as inhibited the differentiation of Th1 and Th17 cells.

CONCLUSIONS

The current research provided evidence that probiotic therapy with L. plantarum and B. animalis can effectively attenuate EAE progression as well as reinforce the polarization of regulatory T-cells.

Invasion of HEp-2 cells by Shigella spp. isolated from acute pediatric diarrhea

Aim:Shigella infection is an important global health problem in developing countries where hygiene is poor and hence shigellosis is a main cause of diarrhoea-associated mortality and morbidity, particularly in children under the age of five. The bacterial entry into colon and rectal epithelial cells has been named ‘bacterium-directed phagocytosis’. This term highlights that the bacteria actively stimulate their own uptake into non-professional phagocytes. The aim of this study was to demonstrate the invasion of HEp-2 cells by Shigella spp. isolated from acute pediatric diarrhea in Tehran, Iran.

Methods: Three-hundred and ten non-duplicative diarrheal stool samples were collected from the children admitted to Children’s Medical Center in Tehran, Iran. Samples were cultured and suspected colonies were identified by routine microbiological and biochemical tests. The invasion of the two isolated Shigella spp. to HEp-2 cells was studied.

Results: Of 310 stool samples, 16 (5.2%) Shigella spp. were isolated, including seven (43.7%) S. sonnei and nine (56.3%) S. flexneri. Four (44.4%) S. sonnei and seven (42.8%) S. flexneri showed invasive phenotype to HEp-2.

Conclusion:Shigella sonnei and S. flexneri are reported as the most prevalent Shigella spp. in nature which infect humans. Invasion of various cell lines gives the chance of survival to Shigella spp. This ability causes more virulent infections in the host. Despite costly and time consuming cell culture techniques, the current method described in this paper is reliable for detecting invasive behavior of Shigella spp. Results have also shown that not all the Shigella spp. are able to invade intestinal epithelial cells.

Profiling of Virulence-associated Factors in Shigella Species Isolated from Acute Pediatric Diarrheal Samples in Tehran, Iran

OBJECTIVES

The genus Shigella comprises the most infectious and diarrheagenic bacteria causing severe diseases, mostly in children under five years of age. This study aimed to detect nine virulence genes (ipaBCD, VirA, sen, set1A, set1B, ial, ipaH, stx, and sat) in Shigella species (spp.) using multiplex polymerase chain reaction (MPCR) and to determine the relation of Shigella spp. from pediatric diarrheal samples with hospitalization and bloody diarrhea in Tehran, Iran.

METHODS

Shigella spp. were isolated and identified using standard microbiological and serological methods. The virulence genes were detected using MPCR.

RESULTS

Seventy-five Shigella spp. (40 S. sonnei, 33 S. flexneri, 1 S. dysenteriae, and 1 S. boydii) were isolated in this study. The prevalence of ial, sen, sat, set1A, and set1B was 74.7%, 45.4%, 28%, 24%, and 24%, respectively. All S. flexneri isolates, while no S. sonnei, S. dysenteriae, or S. boydii isolates, contained sat, set1A, and set1B. All isolates were positive for ipaH, ipaBCD, and virA, while one (1.4%) of the isolates contained stx. The highest prevalence of virulence determinants was found in S. flexneri serotype IIa. Nineteen (57.6%) of 33 S. flexneri isolates were positive for ipaBCD, ipaH, virA, ial, and sat. The sen determinants were found to be statistically significantly associated with hospitalization and bloody diarrhea (p = 0.001).

CONCLUSION

This study revealed a high prevalence of enterotoxin genes in S. flexneri, especially in serotype 2a, and has presented relations between a few clinical features of shigellosis and numerous virulence determinants of clinical isolates of Shigella spp.

Genetic diversity and virulence genes of Salmonella enterica subspecies enterica serotype Enteritidis isolated from meats and eggs

Salmonella enterica subspecies enterica serotype Enteritidis (S. Enteritidis) is one of the leading causes of food-borne gastroenteritis associated with the consumption of contaminated food products of animal origin. Little is known about the genetic diversity and virulence content of S. Enteritidis isolated from poultry meats and eggs in Iran. A total of 34 S. Enteritidis strains were collected from different food sources of animal origin in Tehran from May 2015 to July 2016. All of the S. Enteritidis strains were serotyped, antimicrobial susceptibility tested, and characterized for virulence genes. Pulsed-field gel electrophoresis (PFGE) was also applied for comparison of genetic relatedness. All of the strains harbored invA, hilA, ssrA, sefA, spvC, and sipA genes. A high prevalence of resistance against certain antibiotics such as cefuroxime (79.4%), nalidixic acid (47%), and ciprofloxacin (44.2%) was also observed. Regarding PFGE, S. Enteritidis strains from different sources showed considerable overlap, suggesting the lack of diversity among these isolates. Moreover, no correlation between virulence profiles or antibiotypes and PFGE clusters was observed. In conclusion, our study provided valuable information on virulence gene content, antibiotic resistance, and genetic diversity of S. Enteritidis isolated from food sources.

The Effect of Lactobacillus acidophilus PTCC 1643 on Cultured Intestinal Epithelial Cells Infected with Salmonella enterica serovar Enteritidis

Objectives

Gastrointestinal disorders caused by Salmonella enterica serovar Enteritidis (SesE) are a significant health problem around the globe. Probiotic bacteria have been shown to have positive effects on the immune responses. Lactobacillus acidophilus was examined for its capability to influence the innate immune response of HT29 intestinal epithelial cells towards SesE. The purpose of this work was to assess the effect of L. acidophilus PTCC 1643 on cultured intestinal epithelial cells infected with SesE.

Methods

HT29 cells were cultured in Roswell Park Memorial Institute medium supplemented with 10% fetal bovine serum and 1% penicillin/streptomycin. The cells were treated with L. acidophilus PTCC 1643 after or before challenge with SesE. At 2 and 4 hours post-infection, we measured changes in the expression levels of TLR2 and TLR4 via real-time polymerase chain reaction.

Results

Treatment with L. acidophilus inhibited SesE-induced increases in TLR2 and TLR4 expression in the infected HT29 cells. Moreover, the expression of TLR2 and TLR4 in cells that were pretreated with L. acidophilus and then infected with SesE was significantly higher than that in cells infected with SesE without pretreatment. Taken together, the results indicated that L. acidophilus had an anti-inflammatory effect and modulated the innate immune response to SesE by influencing TLR2 and TLR4 expression.

Conclusion

Our findings suggested that L. acidophilus PTCC 1643 was able to suppress inflammation caused by SesE infection in HT29 cells and reduce TLR2 and TLR4 expression. Additional in vivo and in vitro studies are required to further elucidate the mechanisms underlying this anti-inflammatory effect.

Phage therapy: assessment of the efficacy of a bacteriophage isolated in the treatment of salmonellosis induced by Salmonella enteritidis in mice

AIM

This work aims to isolate and perform comparative studies of a phages active against a Salmonella enteritidis strain from Iran. Also, suitable phage candidates for therapy of mice will be selected.

BACKGROUND

Bacteriophage is of particular interest as a biocontrol agent in the prevention of food-borne illnesses. In recent years tend to use bacteriophages to control pathogenic bacteria has increased. A bacteriophage is considered to be a potent antibiotic alternative for treating bacterial infections.

METHODS

the specific phages against Salmonella Enteritidis was isolated and candidates for therapy of mice will be selected. Mouses divided into the six specific groups. Groups of mice were as follows: A: Bacteri (control) B: Bacteri+ bacteriophage (Simultaneous), C: Bacteri + bacteriophage Four days later, D: Bacteriophage + bacteri four days later E: Bacteri+ Ciprofloxacin (Simultaneous) F: Bacteri+ ciprofloxacin+ bacteriophage (Simultaneous).

RESULTS

In this study, a lytic bacteriophage is isolated and it shows that phage has a head size of 46 nm and without a tail, by using an electron microscope. Oral administration of a single dose of 2 × 109 PFU/mouse bacteriophage enable to protect mouse against salmonellosis and it causes treatment of salmonellosis in mice.

CONCLUSION

The use of this phage compared to ciprofloxacin shows that in addition of the treatment of mouse, it also prevents weight loss.

Prevalence, virulence and antimicrobial resistance patterns of Aeromonas spp. isolated from children with diarrhea

BACKGROUND

Aeromonas spp. cause various intestinal and extraintestinal diseases. These bacteria are usually isolated from fecal samples, especially in children under five years old. The aim of this study was to assess the prevalence of Aeromonas spp. and their antimicrobial resistance profile in children with diarrhea referred to the Children Medical Center in Tehran, between 2013 and 2014.

METHODS

A total number of 391 stool samples were collected from children with ages between 1 day and 14 years old, with diarrhea (acute or chronic), referred to the Children Hospital, Tehran, Iran, between 2013 and 2014. Samples were enriched in alkaline peptone water broth for 24 hours at 37 °C and then cultured. Suspicious colonies were analyzed through biochemical tests. Furthermore, antimicrobial susceptibility tests were carried out for the isolates. Isolates were further studied for act, ast, alt, aerA and hlyA virulence genes using polymerase chain reaction.

RESULTS

In total, 12 isolates (3.1%) were identified as Aeromonas spp.; all were confirmed using the API-20E test. Of these isolates, five A. caviae (42%), four A. veronii (33%) and three A. hydrophila (25%) were identified in cases with gastroenteritis. Second to ampicillin (which was included in the growth medium used), the highest rate of antimicrobial resistance was seen against nalidixic acid and trimethoprim-sulfamethoxazole (5 isolates each, 41.6%) and the lowest rate of antimicrobial resistance was seen against gentamicin, amikacin and cefepime (none of the isolates). Results included 76.4% act, 64.7% ast, 71.5% alt, 83.3% aerA and 11.7% hlyA genes.

CONCLUSION

Aeromonas spp. are important due to their role in diarrhea in children; therefore, isolation and identification of these fecal pathogens should seriously be considered in medical laboratories. Since virulence genes play a significant role in gastroenteritis symptoms caused by these bacteria, Aeromonas species that include virulence genes are potentially suspected to cause severe infections. Moreover, bacterial antimicrobial resistance is increasing, especially against trimethoprim-sulfamethoxazole and nalidixic acid.

Identification of Klebsiella pneumoniae Carbapenemase-producing Klebsiella oxytoca in Clinical Isolates in Tehran Hospitals, Iran by Chromogenic Medium and Molecular Methods

OBJECTIVES

Production of carbapenemase, especially Klebsiella pneumoniae carbapenemases (KPC), is one of the antibiotic resistance mechanisms of Enterobacteriaceae such as Klebsiella oxytoca. This study aimed to investigate and identify KPC-producing K. oxytoca isolates using molecular and phenotypic methods.

METHODS

A total of 75 isolates of K. oxytoca were isolated from various clinical samples, and were verified as K. oxytoca after performing standard microbiological tests and using a polymerase chain reaction (PCR) method. An antibiotic susceptibility test was performed using a disc diffusion method according to the Clinical and Laboratory Standards Institute guidelines. CHROMagar KPC chromogenic culture media was used to examine and confirm the production of the carbapenemase enzyme in K. oxytoca isolates; in addition, PCR was used to evaluate the presence of bla_KPC gene in K. oxytoca strains.

RESULTS

Of a total of 75 K. oxytoca isolates, one multidrug resistant strain was isolated from the urine of a hospitalized woman. This strain was examined to assess its ability to produce carbapenemase enzyme; it produced a colony with a blue metallic color on the CHROMagar KPC chromogenic culture media. In addition, the bla_KPC gene was confirmed by PCR. After sequencing, it was confirmed and deposited in GenBank.

CONCLUSION

To date, many cases of KPC-producing Enterobacteriaceae, in particular K. pneumoniae, have been reported in different countries; there are also some reports on the identification of KPC-producing K. oxytoca. Therefore, to prevent the outbreak of nosocomial infections, the early detection, control, and prevention of the spread of these strains are of great importance.

Isolation and Identification Enterobacter asburiae from Consumed Powdered Infant Formula Milk (PIF) in the Neonatal Intensive Care Unit (NICU)

Enterobacter asburiae (E. asburiae) is a facultative anaerobic, non-spore-forming gram-negative rod-shaped bacterium belonging to the family of Enterobacteriaceae. It is an opportunistic pathogen that its strains are isolated from a variety of clinical and environmental specimens. Since powdered infant formula milk (PIF) is not a sterile product, it is an excellent medium for bacterial growth. The aim of this study was to isolate and identify E. asburiae from PIF in the neonatal intensive care unit (NICU) and determine antimicrobial susceptibility patterns of this bacterium. A total 125 PIF samples were purchased from drug stores between June 2011 to March 2012. E. asburiae was isolated according to FDA method. For final confirmation, biochemical tests embedded in the API-20E system were used. The drug susceptibility test was performed using the disc diffusion method according to CLSI recommendations. Out of the 125 PIF samples investigated, 2 (1.6%) samples were positive for E. asburiae. All isolated strains were uniformly susceptible to aztreonam, cefotaxim, amikacin, streptomycin, nalidixic acid, meropenem, tetracycline, ceftazidime, and colistin. Variable susceptibility was seen to the some antimicrobial agents tested. Each country should categorize its own designed guidelines for the preparation and handling of PIF adapted to the local environment. Moreover, the pathogenesis of the E. asburiae in infants hospitalized in NICU and other groups such as immunosuppressed patients and HIV infected individuals is uncertain and requires further study.

The Effect of Campylobacter concisus on Expression of IL-18, TNF-α and p53 in Barrett's Cell Lines

BACKGROUND

Barrett's oesophagus is a pre-malignant condition at gastroesophageal junction in which normal squamous epithelium is replaced by columnar shape epithelium, which predisposes oesophageal adenocarcinoma. It is known that Barrett's oesophagus evolves as a consequence of chronic gastro-oesophageal reflux disease. Although progression of Barrett's oesophagus to adenocarcinoma is still unclear, increasing incidence of oesophageal cancer and mortality worldwide make its study necessary. Several investigations have been made on the aetiology of oesophageal cancer. Most of them assessed genetical or environmental factors. However, potential role of bacteria in the development of oesophageal adenocarcinoma as a new environmental factor has not been addressed. Previous study on Barrett's disease detected presence of Campylobacter concisus as a new emerging pathogen on Barrett's and oesophageal cancer samples compared with healthy individuals. This indicates that this organism might involve in the progression of Barrett's to oesophageal adenocarcinoma.

OBJECTIVES

This study aimed to determine the effects of C. concisus on expression of three biomarkers including interleukin-18 (IL-18), tumour necrosis factor-α (TNF-α) and tumour suppressor gene (p53) in three Barrett's cell lines.

MATERIALS AND METHODS

Quantitative real-time PCR assays were developed to measure expression of pro-inflammatory mediators (IL-18 and TNF-α) and gene expression of p53 in Barrett's cell lines in co-culture with C. concisus.

RESULTS

The mentioned organism was able to modulate considerably expression of p53, TNF-α and IL-18 in a time-dependent manner.

CONCLUSIONS

The results showed that microorganism influences expression of carcinogenesis biomarker and cytokines in cell line models and possibility promotes oesophageal adenocarcinoma.

Antimicrobial Activity of Lactobacillus spp. Isolated From Fecal Flora of Healthy Breast-Fed Infants Against Diarrheagenic Escherichia coli

Background:

Among the enteric pathogens, diarrheagenic Escherichia coli are important causes of diarrhea in children in both developing and industrialized countries. Some Lactobacillus species are commonly used as probiotics, with effects especially against acute diarrhea in childhood.

Objectives:

The aim of this study was to explore antimicrobial activity of Lactobacillus strains isolated from fecal flora of healthy breast-fed infants against five diarrheagenic E. coli pathotypes such as enteroaggregative E. coli (EAEC), enterohaemorrhagic E. coli (EHEC) enteroinvasive E. coli (EIEC), enteropathogenic E. coli (EPEC) and enterotoxigenic E. coli (ETEC).

Materials and Methods:

Fecal samples were collected from seven healthy breast-fed infants between 1 to 18 months of age in Tehran city, Iran. Identification of Lactobacillus isolates was performed by biochemical and 16S rRNA gene sequencing methods. An agar well diffusion assay was used for detection of antimicrobial activity of Lactobacillus isolates against five diarrheagenic E. coli pathotypes.

Results:

A total of 20 Lactobacillus isolates were identified from stool samples. Lactobacillus fermentum was the most frequently isolated strain, followed by L. plantarum and L. rhamnosus. Seven Lactobacillus strains including L. fermentum (four isolates), L. paracasei (one isolate), L. plantarum (one isolate) and L. rhamnosus (one isolate) had a mild inhibitory activity against diarrheagenic E. coli. The mechanism of inhibitory activity of Lactobacillus strains appeared to be due to the production of organic acids or hydrogen peroxide.

Conclusions:

Our findings show that Lactobacillus strains with human origin had a mild inhibitory activity against the diarrheagenic E. coli, and these strains may be useful as probiotic candidates in prevention of intestinal infections caused by diarrheagenic E. coli.

Effects of probiotic Lactobacillus acidophilus and Lactobacillus casei on colorectal tumor cells activity (CaCo-2)

BACKGROUND

The probiotic microorganisms are live normal flora that provide nutritional benefits. When probiotic administered in adequate amounts, they also confer a health benefit on the host. Different mechanisms of probiotic effects include the following: stimulating the immune system, modifying the composition of normal intestinal flora and preventing the carcinogenic activity of fecal enzymes. In this study, direct effects of probiotic lactobacilli on tumor cells were investigated.

METHODS

Supernatants and bacterial extracts of two standard Lactobacillus species (L. acidophilus and L. casei) were prepared and CaCo-2 cells were treated with them. Probiotic effects on cell proliferation, necrosis, apoptosis, migration and invasion were assessed.

RESULTS

The supernatants of Lactobacilli decreased cell proliferation and increased cell apoptosis, however, no significant effect on cell necrosis was reported. In contrast, Lactobacilli extract, reduced cell proliferation and increased cell apoptosis. Lactobacilli extract also led to cell necrosis. Furthermore, both supernatants and cell extracts of the probiotic agents resulted in decreased cells' migration and invasion.

CONCLUSION

In this study, it was shown that Lactobacilli probiotics useful effects are not confined to the enhancement of the immune system; however, they effectively suppress the malignant phenotypes of colorectal cancer cells.

Study on Bacterial Strains Causing Blood and Urinary Tract Infections in the Neonatal Intensive Care Unit and Determination of Their Antibiotic Resistance Pattern

BACKGROUND

Infections are considered as one of the main factors of neonatal mortality, especially in developing countries. Blood and urine infections are one of the most prevalent infectious factors among the infants. On the other hand, resistance against antimicrobial factors is one of the major problems in the world, and it is important to be informed about antibiotic resistance pattern of microorganisms for treatment of infections.

OBJECTIVES

The aim of this study was to examine the bacterial strains causing blood and urinary tract infections in Neonatal Intensive Care Unit (NICU) and determine their antibiotic resistance pattern.

MATERIALS AND METHODS

In this study, the microorganisms of 150 blood and urine samples of infants hospitalized in NICUs of Imam Hussein Hospital, Children Hospital Center and Bahrami Hospital in Tehran, Iran, were collected during seven months, and the antimicrobial resistance patterns of the isolates were studied by the Kirby-Bauer test.

RESULTS

During the seven-month study on 105 samples, including 85 (81%) urine samples and 20 (19%) blood samples, 81 samples (77.1%) were Gram-negative and 24 (22.9%) were Gram-positive organisms. Klebsiella pneumoniae (30.5%) was the most common Gram-negative microorganisms and Staphylococcus epidermidis (11.4%) was the most prevalent Gram-positive microorganisms. The most antimicrobial susceptibility in Gram-negative microorganisms was shown to ciprofloxacin (84.2%) and in Gram- positive ones was shown to vancomycin (83.3%).

CONCLUSIONS

This results of the study show that the most contamination in NICUs is from Gram-negative bacteria and ciprofloxacin is the most effective antibiotic for treatment. Thus, the control of infections in NICUs in hospitals is very important.