The role of microbiota in colorectal cancer.

Cancer is one of the most important causes of death throughout the world, and the mortality rate is increasing significantly due to the aging of the population. One of the most common types of cancer is colorectal cancer (CRC). Human microbial ecosystems use metabolism to make important impacts on the body physiology. An intensive literature review was made to investigate the correlations between human gut microbiota and the incidence of CRC. The results of these studies show that there are differences in the composition of microbiota between CRC patients and normal people and the microorganisms in CRC patients are very different from healthy individuals. Therefore, changes in the microbiome can be used as a biomarker for the early detection of CRC. On the other hand, the intestinal flora is may be act as a powerful weapon against CRC in the future.

Occurrence of plasmid-mediated quinolone resistance genes in Pseudomonas aeruginosa strains isolated from clinical specimens in southwest Iran: a multicentral study.

This study aimed to assess the presence of qnrA, qnrB, qnrC, qnrD, qnrS, qepA, and aac(6')-Ib-cr determinants as well as quinolone resistance pattern of clinical isolates of P. aeruginosa in Ahvaz, southwest Iran. A total of 185 clinical isolates of P. aeruginosa were collected from 5 university-affiliated hospitals in Ahvaz, southwest Iran. The disk diffusion method was applied to assess the quinolone resistance pattern. The presence of qnrA, qnrB, qnrC, qnrD, qnrS, qepA, and aac(6')-Ib-cr genes was investigated by the polymerase chain reaction (PCR) method. Overall, 120 (64.9%) isolates were non-susceptible to quinolones. The most and the less quinolone resistance rates were observed against ciprofloxacin (59.4%) and ofloxacin (45.9%), respectively. The prevalence rates of qnr genes were as follows: qnrA (25.8%), qnrB (29.2%), and qnrS (20.8%). The qnrB gene was the most common type of qnr genes. The qnr genes were occurred in 37.5% (n = 45/120) of quinolne-resistant isolates, simultaneously. The qnrC, qnrD, qepA, and aac(6')-Ib-cr genes were not recognized in any isolates. In conclusion, the ofloxacin was the most effective quinolone. This study was the first to shed light on the prevalence of PMQR genes among P. aeruginosa isolates in southwest Iran.

Associations between seroprevalence of Helicobacter pylori and ABO/rhesus blood group antigens in healthy blood donors in southwest Iran.

OBJECTIVE: To investigate correlations between ABO/rhesus (Rh) blood group antigens and anti-Helicobacter pylori and anti-cytotoxin-associated gene A (CagA) seropositivity in blood donors. METHODS: A total of 311 blood donors were enrolled. ABO and Rh blood groups were determined using hemagglutination tests. Specific anti-H. pylori IgG and anti-CagA IgG antibodies in sera were quantitated by enzyme-linked immunosorbent assay. Correlations between blood groups and anti-H. pylori and anti-CagA seropositivity were evaluated using the Chi-square test. RESULTS: O+ was the most frequent blood type (38%, n = 118). Anti-H. pylori IgG seropositivity was observed in 240 (77.2%) blood donors, while anti-CagA IgG seropositivity was observed in 132 (42.5%) blood donors. Although seropositivity rates for both anti-H. pylori and anti-CagA IgG were higher in individuals with blood type O, no statistically significant associations were observed between seropositivity and any ABO/Rh blood groups. CONCLUSION: Individuals with blood type O may have higher rates of H. pylori seropositivity.

Prevalence of Extended-Spectrum Beta-Lactamase-Producing Enterobacteriaceae Causing Bloodstream Infections in Cancer Patients from Southwest of Iran.

INTRODUCTION: This study aimed to evaluate the frequency rate of extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE) causing bloodstream infections (BSIs) in cancer patients referred to one of the major referral hospitals in Ahvaz city, southwest Iran. MATERIALS AND METHODS: In this study, 1700 blood cultures were collected from 610 cancer patients suspected to have BSI from October 2016 to August 2017 referred to the Shafa cancer hospital, Ahvaz, southwest of Iran. The blood culture bottles were incubated aerobically at 35-37ºC for 24 hours and then sub-cultured on routine microbiology culture media. The bacterial colonies were identified using standard tests. The antibiotic susceptibility testing was achieved by the disc-diffusion method. The phenotypic detection of ESBLs was carried out by the combination disc-diffusion test (CDDT). Finally, the polymerase chain reaction (PCR) was performed to investigate the presence of bla TEM, bla CTX, bla SHV, and bla PER genes. RESULTS: The prevalence of BSI in cancer patients was 16.4% (100/610). Gram-negative rods with rate of 74% (74/100) were the most prevalent bacteria. The frequency of Enterobacteriaceae family was 21% including Escherichia coli (n: 8), Klebsiella pneumoniae (n: 6), Enterobacter spp. (n: 5), Citrobacter freundii (n: 1), and Serratia marcescens (n: 1). All isolates were multidrug-resistant (resistance to three or more antibiotics). The results of CDDT showed that 42.8% (9/21) of Enterobacteriaceae isolates had a positive ESBL test of which 100% (9/9) indicated positive band for at least one of the ESBL genes by PCR method. The bla CTX-M and bla TEM genes were detected in 38% (8/21) and 23.8% (5/21) of isolates, respectively, while the bla SHV and bla PER were not detected in any isolates. CONCLUSION: Based on the results, surveillance, and antibiotic stewardship programs should be implemented for cancer patients to prevent the spread of more ESBL-PE that have limited therapeutically choices.

Investigation of SCCmec types I-IV in clinical isolates of methicillin-resistant coagulase-negative staphylococci in Ahvaz, Southwest Iran.

Today methicillin resistant coagulase-negative staphylococci (MR-CoNS) are important in terms of causing significant nosocomial infections. Besides, MR-CoNS are confirmed as the reservoir of SCCmec elements that carry mecA (methicillin-resistant) gene. Hence, the present study was designed to evaluate the susceptibility pattern, prevalence and diversity of SCCmec types I, II, III, and IV in MR-CoNS strains. In this cross-sectional study, 44 clinical isolates of MR-CoNS were identified using the cefoxitin disc method and further confirmation by polymerase chain reaction (PCR) amplification of the mecA gene. Antimicrobial susceptibility of isolates was investigated by disc diffusion. The identification of CoNS was done by amplification and sequencing of the tuf gene. Multiplex PCR method was done for the determination of SCCmec types. In the present study, the Staphylococcus epidermidis and Staphylococcus haemolyticus were the most predominant isolates with a prevalence of 45.4%. The highest resistance rates were observed against erythromycin (84.1%) and clindamycin (75%). Multiplex PCR revealed the SCCmec type I as the predominant type in the present study. Our study showed that there was no significant relationship between the presence of different types of SCCmec elements and resistance to antibiotics. The present study highlighted a frequent prevalence of MR-CoNS harboring SCCmec type genes in Ahvaz, southwest of Iran. Thus, the molecular typing and periodical monitoring of their drug resistance pattern should be considered in national stewardship programs to designing useful antibiotic prescription strategies.

Loop-mediated isothermal amplification for detection of Legionella pneumophila in respiratory specimens of hospitalized patients in Ahvaz, southwest Iran.

BACKGROUND: Legionnaires' disease is an important public health problem that can cause substantial mortality and morbidity. Legionnaires' disease-risk estimation may be compromised by uncertainties in Legionella-detection methods. The aim of this study was the detection of L. pneumophila in respiratory specimens of hospitalized patients with respiratory symptoms by culture, PCR, and loop-mediated isothermal amplification (LAMP) methods. METHODS: Sputum and bronchoalveolar lavage samples were obtained from patients with pneumonia admitted to teaching hospitals in Ahvaz, Iran from June 2016 to March 2017. Isolation of Legionella spp. was done by culturing the samples directly onto buffered charcoal-yeast extract and modified Wadowsky-Yee agar medium. Then, PCR and LAMP assays were performed for detection of L. pneumophila via its mip gene in respiratory specimens. RESULTS: A total of 100 respiratory specimens were collected. Our results showed that 1% of the samples were culture positive for Legionella spp., and 3% and 7% of samples were positive for L. pneumophila using the mip gene on PCR and LAMP assays, respectively. CONCLUSION: Legionnaires' disease should be considered in the diagnosis of pulmonary infectious diseases. Also, the LAMP assay is a faster method with higher sensitivity and specificity than conventional methods, such as PCR and culture, for laboratory diagnosis of Legionnaires' disease.

Prevalence and antimicrobial resistance of Shigella species isolated from diarrheal patients in Ahvaz, southwest Iran.

INTRODUCTION: Shigellosis is a significant global human health problem, and Shigella is in charge of almost 165 million cases of this disease annually, of whom 163 million cases are in developing countries and 1.5 million cases are in developed countries. The main aims of the current survey were to identify Shigella spp. isolated from diarrheal patients by conventional biochemical tests, determine the antimicrobial susceptibility profiles by disk diffusion method, and detect the ipaH gene using the PCR assay. METHODS: The bacterial isolates were identified as Shigella spp. by microbiological tests and were serogrouped by the slide agglutination test. Antimicrobial susceptibility testing was performed using the disk diffusion method. PCR was performed to detect the ipaH gene. RESULTS: The Shigella strains were isolated from 522 patients with various diarrhea, including bloody diarrhea (3%), mucoid plus bloody diarrhea (1.9%), mucoid diarrhea (3.2%), and watery diarrhea (3.2%). Overall, 69 (13.2%) isolates were positive for Shigella spp., of which 34 (49.3%) serotypes were identified as Shigella flexneri, 22 (31.9%) serotypes were identified as Shigella sonnei, 9 (13%) serotypes were identified as Shigella boydii, and 4 (5.8%) serotypes were identified as Shigella dysenteriae. Antibiotic susceptibility tests revealed that the highest resistance percentage was related to ampicillin (82%) and trimethoprim-sulfamethoxazole (77%), and ciprofloxacin and ceftriaxone were the best antibiotics against Shigella isolates. CONCLUSION: We concluded that Shigella spp. can be considered as an etiological agent of diarrhea in southwest Iran. Since the drug resistance pattern of Shigella differs geographically and over time within a country, continuous and regular surveillance program is necessary.

Prevalence of enterotoxin-encoding genes among diverse Shigella strains isolated from patients with diarrhea, southwest Iran.

Shigella spp. are a major cause of bacillary dysentery, particularly among children in developing countries such as Iran. This study aimed to investigate the presence of two important Shigella enterotoxins (ShET-1 and ShET-2), encoded by the set and sen genes, respectively, by polymerase chain reaction (PCR) assay among Shigella species isolated from children affected by shigellosis in Ahvaz, southwest of Iran. In this cross-sectional study, from June 2016 to April 2017, altogether 117 Shigella isolates were collected from fecal specimens of children aged <15 years with diarrhea in Ahvaz, southwest Iran. All isolates were identified by standard microbiological and molecular methods. The presence of enterotoxin genes was determined by PCR. The most prevalent isolate was Shigella flexneri (47.9%), followed by Shigella sonnei (41%) and Shigella boydii (11.1%), respectively. Shigella dysenteriae was not detected in patients' samples. The frequencies of set1A, set1B, and sen genes were 5.1% (6/117), 15.4% (18/117), and 76.9% (90/117), respectively. This study provides initial background on the prevalence and distribution of the Shigella enterotoxin genes in Shigella isolates in southwest of Iran. In addition, this study revealed a high prevalence of sen enterotoxin gene in Shigella species.

Antibiotic resistance pattern and molecular characterization of extended-spectrum ß-lactamase producing enteroaggregative Escherichia coli isolates in children from southwest Iran.

INTRODUCTION: Enteroaggregative Escherichia coli (EAEC) has been implicated as an emerging cause of traveler's diarrhea, persistent diarrhea among children, and immunocompromised patients. The present study aimed to investigate the prevalence of antibiotic resistance, extendedspectrum ß-lactamase (ESBL) production, and virulence factors of EAEC isolates obtained from Iranian children suffered from diarrhea. MATERIALS AND METHODS: In this cross-sectional study, from March 2015 to February 2016, 32 EAEC isolates were collected from fecal samples of children aged <12 years with diarrhea in southwest of Iran. All EAEC isolates identified using phenotypic and molecular methods and the cell line adhesion assay. Antimicrobial susceptibility testing was determined using disk diffusion method. The presence of virulence factors and ESBL resistance genes were determined by polymerase chain reaction. RESULTS: Overall, 28.1% (9/32) of the isolates were positive for at least one of virulence genes. The most frequent gene was aap with a frequency of 96.9%. Neither aafA nor aggA gene was detected among all of the EAEC isolates. Antimicrobial susceptibility testing revealed the highest resistance rate to ampicillin (100%) and co-trimoxazole (100%), followed by ceftriaxone (81.3%). Further analysis revealed that the rate of ESBLs-producing isolates was 71.9% (23/32). Polymerase chain reaction screening revealed that 87.5% and 65.5% of EAEC isolates were positive for blaTEM and blaCTX-M genes, respectively, and 17 (53.1%) of isolates contained both blaTEM and blaCTX-M genes. CONCLUSION: The high detection rate of ESBL-producing EAEC isolates accompanied with virulence genes highlights a need to restrict infection control policies in order to prevent further dissemination of the resistant and virulent EAEC strains.