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Reza Ranjbar, Abbas Farahani Molecular Biology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, IranCorrespondence: Reza RanjbarMolecular Biology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, IranTel +98 21 8803 9883Email Ranjbarre@gmail.comAbstract: Shigella spp. are a common cause of diarrheal disease and have remained an important pathogen responsible for increased rates of morbidity and mortality caused by dysentery each year around the globe. Antibiotic treatment of Shigella infections plays an essential role in reducing prevalence and death rates of the disease. However, treatment of these infections remains a challenge, due to the global rise in broad-spectrum resistance to many antibiotics. Drug resistance in Shigella spp. can result from many mechanisms, such as decrease in cellular permeability, extrusion of drugs by active efflux pumps, and overexpression of drug-modifying and -inactivating enzymes or target modification by mutation. Therefore, there is an increasing need for identification and evolution of alternative therapeutic strategies presenting innovative avenues against Shigella infections, as well as paying further attention to this infection. The current review focuses on various antibiotic-resistance mechanisms of Shigella spp. with a particular emphasis on epidemiology and new mechanisms of resistance and their acquisition, and also discusses the status of novel strategies for treatment of Shigella infection and vaccine candidates currently under evaluation in preclinical or clinical phases.Keywords: Shigella, antibiotics, resistance, drug resistance, mechanism, treatment, biofilm, efflux pumps, prevention, vaccine

Ahmad Farajzadah Sheikh,1,2 Hamed Goodarzi,1–3 Mohammad Jaafar Yadyad,1 Sajad Aslani,4 Mansoor Amin,1,2 Nabi Jomehzadeh,5 Reza Ranjbar,3 Mina Moradzadeh,1 Samireh Azarpira,1 Mohamad Reza Akhond,6 Mohamad Hashemzadeh1,21Infectious and Tropical Diseases Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran; 2Department of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran; 3Molecular Biology Research Center, Baqiyatallah University of Medical Science, Tehran, Iran; 4Student Research Committee, Kerman University of Medical Sciences, Kerman, Iran; 5Abadan Faculty of Medical Sciences, Abadan, Iran; 6Department of Statistics, Mathematical Science and Computer Faculty, Shahid Chamran University, Ahvaz, IranBackground: Different Escherichia coli phylogenetic groups, such as A, B1, B2, and D, have four functional groups – adhesins, microcins, toxins, and capsules – which can cause urinary tract infections (UTIs). A phylogenetic group with a high virulence content becomes a worldwide health concern. Resistance to antimicrobial agents increasingly complicates the management of E. coli extraintestinal infections, as a major source of illness, death, and increased health care costs. The aim of this study was to determine the virulence content and the antimicrobial susceptibility pattern of different uropathogenic E. coli (UPEC) phylogenetic groups in Ahvaz, Iran.Methods: Phylogenetic groups, virulence-associated genes (VAGs), and antimicrobial susceptibility tests were detected by molecular and phenotypic methods in a total of 232 clinically well-characterized E. coli strains, isolated from two collections of patients with hospital-acquired (HA) and community-acquired (CA) UTIs.Results: Our results revealed that among 232 UPEC strains, the most frequent phylogenetic group was phylogroup D (58%) with the greatest content in virulence factors, including kpsM (23%), neuA (76.3%, capsule), cnf (29.6%, toxin), and Pap (54.8%, adhesin). Phylogroups D and, to a lesser extent, B2 were the most drug-resistant phylogroups. In addition, phylogroup D was responsible for the majority of HA (64.7%) and CA (48.4%) infections.Conclusion: Among UPEC strains causing UTIs, different phylogroups, through different VAGs, could cause severe infection. Knowledge about the distribution of the four functional groups and VAGs belonging to these phylogroups would significantly help to confine and prevent the development of lethal infection caused by these strains.Keywords: uropathogenic Escherichia coli, drug resistance, virulence factors, Iran

Reza Ranjbar,1 Ali Fatahian Kelishadrokhi,2 Mohammad Chehelgerdi21Molecular Biology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran; 2Biotechnology Research Center, Shahr-e Kord Branch, Islamic Azad University, Shahr-e Kord, IranPurpose: Virulent and resistant Klebsiella pneumoniae strains are considered as one of the most significant causes of hospital-acquired infections. The present investigation was done to study the distribution of virulence factors, capsule serotypes and phenotypic and genotypic evaluation of antibiotic resistance of the K. pneumoniae strains isolated from hospital-acquired infections.Patients Materials and methods: Two hundred and sixty different types of hospital-acquired infections were collected and cultured. Antibiotic resistance pattern of K. pneumoniae isolates and their molecular characterization were studied using disk diffusion and PCR, respectively.Results: One hundred and fifty out of 260 (44.22%) hospital-acquired infections harbored K. pneumoniae. Urine samples (63.75%) had the highest prevalence of K. pneumoniae, while wound (33.33%) had the lowest. K. pneumoniae strains harbored the highest prevalence of resistance against ampicillin (100%), cefuroxime (100%), amoxicillin/clavulanic acid (95.65%) and ceftazidime (95.52%). FimH-1 (93.04%), traT (92.17%), mrkD (84.34%), and entB (80.86%) were the most commonly detected virulence genes. AcrAB (96.52%) and tolC (85.21%) were the most commonly detected antibiotic resistance genes. Prevalence of ompK35 and ompK36 virulence genes were 75.65% and 79.13%, respectively. Prevalence of K1 and K2-positive serotypes were 27.82% and 6.96%, respectively.Conclusions: High prevalence of resistance against several types of antibiotics and simultaneous presence of some virulence factors and multi-drug resistance genes pose an important public health issue.Keywords: Klebsiella pneumoniae, antibiotic resistance pattern, antibiotic resistance genes, capsule serotypes, virulence genes, hospital infections

Reza Ranjbar,1 Mohammad Chehelgerdi2 1Molecular Biology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran; 2Biotechnology Research Center, Shahr-e Kord Branch, Islamic Azad University, Shahr-e Kord, Iran Purpose: The present study was done to assess the prevalence rate, antibiotic resistance pattern and genotyping status of the Helicobacter pylori strains isolated from human and animal gastric biopsy samples.Patients and methods: A total of 1,150 gastric biopsy samples were randomly collected from humans (children and adults) and animals (cows, sheep and goats). All samples were subjected to culture, urease test and histopathologic examination. H. pylori isolates were also confirmed using the 16S rRNA gene PCR-amplification. Antibiotic resistance pattern was assessed by the disk diffusion method. Distribution of different genotypes was studied by PCR.Results: The prevalence of H. pylori in gastric biopsy samples which were studied using urease test, culture and histological examination were 57.04%, 55.40% and 60.80%, respectively. Samples that were collected from adult humans (78%) and sheep (70%) had the highest prevalence of H. pylori strains, while those of goats (0.6%) and cows (4%) had the lowest. Findings of the culture method were confirmed using PCR-based amplification of 16S rRNA. Distribution of H. pylori among the gastric ulcers, duodenal ulcers, chronic gastritis gastric cancer and chronic cancer samples were 10.40%, 15.70%, 96.50%, 0.60% and 3.14%, respectively. H. pylori strains harbored the highest prevalence of resistance against ampicillin (74.4%), clarithromycin (63.4%), trimethoprim (61.5%) and metronidazole (61.5%). The most commonly detected genotypes among the H. pylori strains isolated from different types of biopsy samples were cagA (84.79%), vacA m2 (55.95%), vacA s1a (49.84%), cagE (48.58%), iceA1 (47.02%) and iceA2 (47.02%).Conclusion: High prevalence of antibiotic resistance and virulent genotypes indicates an important public health issue. Similarities in antibiotic resistance and genotyping pattern of H. pylori strains isolated from humans and animals may show their similar routes of infection. Keywords: Helicobacter pylori, virulence factor, antibiotic resistance, genotypes, clinical samples

Pegah Shakib1,2, Sobhan Ghafourian1, Mohammad Reza Zolfaghary2, Reza Hushmandfar3, Reza Ranjbar4, Nourkhoda Sadeghifard11Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam; 2Department of Microbiology, Qom Branch, Islamic Azad University of Qom, Qom; 3Faculty of Veterinary Medicine, Ilam University, Ilam; 4Molecular Biology Research Center, Baqiyatallah University of Medical Sciences, Tehran, IranBackground: The aims of this study were to confirm the presence of OmpK35 and OmpK36 in extended-spectrum beta-lactamase-producing and nonextended-spectrum beta-lactamase-producing Klebsiella pneumoniae and to determine the relationship between porin expression and resistance to third-generation cephalosporins.Methods: Fifty-two K. pneumoniae isolates were obtained and analyzed for extended-spectrum beta-lactamase and for OmpK35 and OmpK36.Results: Twenty-two (42.3%) isolates of K. pneumoniae were extended-spectrum beta-lactamase producers. The OmpK35 profile in K. pneumoniae producing extended-spectrum beta-lactamase showed the presence of porin protein in ceftazidime-sensitive K. pneumoniae (six isolates), and the OmpK36 profile in K. pneumoniae producing extended-spectrum beta-lactamase revealed isolates sensitive to cefotaxime (n = 8) and ceftriaxone (n = 6). All nonextended-spectrum beta-lactamase-producing K. pneumoniae showed the presence of OmpK35 and OmpK36 porin proteins.Conclusion: The presence of OmpK35 is mostly related to ceftazidime susceptibility and less to cefotaxime and ceftriaxone susceptibility, while OmpK36 expression is seen more often in cefotaxime-sensitive isolates. OmpK35 and OmpK36 indicate nonextended-spectrum beta-lactamase producing strains, and their presence is important when selecting an antimicrobial agent.Keywords: Klebsiella pneumoniae, extended-spectrum beta-lactamase producing strains, porin expression