Concerns in the Design and Development of Novel Antimicrobial Peptides

Peptide and protein based therapeutics are the most promising approaches in today medicine. Bioactive peptides can be valuable drugs in the treatment of various illnesses, such as cardiovascular and neurodegenerative diseases. Cell toxic peptides can be considered for cancer or infection therapy. Antimicrobial peptides (AMPs) are one of the most interesting antibiotic groups in this regard, especially in drug resistance infections. Numerous AMPs have been discovered from the natural source; however, artificial synthetic ones have been also developed based on rational design or bioinformatics modeling. Physicochemical features of AMPs are highly important in their antibacterial activity as well as their toxicity. The best AMP is the one that has selective potent antimicrobial bioactivity and no or least hemolytic and cytotoxic effect. In this review, various structural factors affecting the AMPs bioactivity, such as AMPs size, charge, amphipathicity, and amino acid sequence are illustrated considering the most recently published articles. Finally, the trends in AMP design and development are discussed. HIGHLIGHTS•Antimicrobial peptides are highly interesting antibiotics in multi-drug resistance infections.•Antimicrobial peptides are short peptides with less than 50 amino acids and overall positive charge.•First and second structural features of AMPs are important factors in their bioactivities.•Cyclization and branching of AMPs could affect their pharmacokinetic and pharmacodynamics

Frequency of Class 1 Integrons among Escherichia coli Isolates of Patients with Urinary Tract Infection

Background: Recent studies demonstrated an increased pattern of drug resistance in uropathogenic Escherechia coli (E. coli) which is considered as the most common cause of urinary tract infections (UTIs). Present investigation was undertaken to evaluate antibiotic resistance pattern of E. coli causing UTIs obtained from urine samples and their relationship with integron class1. Apart from that, special emphasis was given on mediated and transferable antibiotic resistance in E. coli as well as the mobilized integrons that contribute to dissemination of antibiotic resistance. Methods and Materials: Susceptibility of isolates to 12 antibiotics was tested by the Kirby -Bauser disk diffusion method. The sensitivity was monitored by zone of inhibition according to the clinical and laboratory standard institute (CLSI) guidelines. Plasmid DNA from E. coli strains was tested for class 1 integron by PCR. Results: Rate of resistance to the 12 antibiotics is as follows: Ampicillin (89.4%), Cefotaxim (31%), Ciprofloxacin (22.4%), Aztreonam (21.7%), Ceftazidim (21.1%), Ceftriaxon (20.5%), Co-trimoxazole (19.9%), Gentamicin (15.5%), Amikacin (7.5%), Cefepim (11.8%), Nitrofurantoin (6.2) and Imipenem (1.9%). Existence of integron was confirmed in 41.9% of isolates. Significant association was evaluated by PCR between resistance to Gentamicin, Amikacin, Gentamicin, Amikacin, Cefotaxim, Ceftazidim, Ceftriaxon, Aztreonam, Ciprofloxacin and Co-trimoxazole with the existence of class 1 integrons. Conclusion: Imipenem could be used as the initial therapy for E. coli in UTIs. Similar studies are essential to determine appropriate guidelines for empirical therapy which vary by location

Prevalence of group B streptococcus colonization in Iranian pregnant women: A systematic review and meta-analysis

Background: Group B Streptococcus (GBS) is an important pathogen in newborns and pregnant women. Objective: The present study was carried out to estimate the prevalence of GBS colonization in pregnant women in Iran. Materials and Methods: This systematic review and meta-analysis was based on Preferred Reporting Items for Systematic Reviews and Meta-Analysis guideline using the national databases including Society for Information Display, Magiran, Irandoc,Iran Medex, and international databases including MEDLINE, Web of Science, Scopus,PubMed, Science-Direct, Cochrane, Embase, Elton Bryson Stephens Company, Centre for Evidence-Based Medicine, Cumulative Index to Nursing and Allied Health Literature, and Google Scholar, published by 01/30/2017. The I2 index was used to measureheterogeneity between the studies. Results: In a total of 667 documents, 30 (4.49%) were selected. In this study, the prevalence of GBS colonization in 10090 Iranian pregnant women was calculated as 13.65% [confidence interval (CI): 95%: 10.56–17.45]. Based on geographic region,24.63% [CI: 95%: 11.52–45.06] in the West and 8.75% [CI: 95%: 6.43–11.8] in the East were the highest and lowest areas in Iran, respectively, and were statistically significant (p = 0.001). Also, with regards to swapping sampling area, Vaginal with 11.96%, Vaginal and Rectal with 13.62%, and Anal and Vaginal with 25.63% were the least to the greatest, respectively, and were statistically significant (p = 0.001). Conclusion: Therefore, based on the recommendation of Centers for Disease Control and Prevention as reported by the Ministry of Health and Medical education, early diagnosis, and screening of high-risk women should be done at 35–37 weeks of pregnancy. Key words: Streptococcus agalactiae, Iran, Pregnancy, Prevalence, Female

A Comparison of Two-Step Tuberculin Skin Test between Health-Care Workers and Nonhospital Employees

Background: The tuberculin test is widely used to identify tuberculosisinfection. Some individuals infected with Mycobacteriumtuberculosis may have an initial negative skin test reactionto tuberculin. The two step purified protein derivative skin testcan decrease misinterpretation of tuberculin test .This study wasaimed at comparing the two- step tuberculin skin test and boosterphenomenon in health care workers and non hospital employees.Methods: One hundred and eighty five health service employeesfrom Razi University Hospital and 181 non hospitalemployees were subjected to an initial tuberculin skin test.Those who were negative on the first test underwent a secondone 2 weeks later. The reactions to the tests were measured 72hours later. Tests with an induration of ≥ 10 mm was consideredpositive. Moreover, second tests with an induration of atleast 6 mm increase relative to the relevant first tests wereconsidered positive.Results: Compared to non hospital employees (n=79, 43.6%), asignificantly higher number of health care workers (n=113,61.1%) were positive on the first tuberculin test. 18.5 % of healthcare workers and 31.5% of non hospital employees demonstrateda boosted reaction after the second tuberculin test. The occurrenceof boosted reaction was significantly associated with ageboth groups. There was no association between the presence ofBCG scars and the occurrence of boosted reaction.Conclusion: the present study shows that the prevalence of TBwas higher among health care worker than non hospital employees.Moreover, it demonstrated that non hospital employeeshad a higher age-associated booster reaction to the second tuberculinskin test than health care workers. Therefore, to avoidmissing false negative cases, it would be necessary to do a secondtuberculin test for subjects with a negative reaction to theinitial test, especially in subjects older than 40 years

Comparative Investigation of Bachelor’s Degree Curriculum of Clinical Laboratory Sciences in Iranian Universities of Medical Sciences and World\'s Top Universities

Background and Aim: Nowadays, clinical laboratories play important roles in health care systems and well-trained staff are in need more than ever before. Thus, educating students in this field is one of the best approaches in saving energy and expenditure of health-care systems in any community. The aim of this descriptive study was to assess the different aspects of the pedagogical curriculum for Iranian laboratory science students compared with that of world's leading universities. Materials and Methods: In 2014, pedagogical curriculum of this major in Iran was compared to the curriculum of 17 prestigious universities in the world. Also, a questionnaire was filled out by the faculty members of medical universities who were involved in training clinical laboratory science's students. Results: The results showed that the Iranian curriculum has various drawbacks in clinical apprenticeship for students, and is short of specific credits such as Microbiology and Immunohematology. In addition, lack of practical or applied credits like Urine Analysis, Body Fluids, Microscopy and Medical Ethics was noticed. It was discovered that little attention was paid to preparing students for research. Conclusions: Considering the findings of the current survey, decreasing the credits offered in each semester with proper training course scheduling and monitoring the students, will not only help the students to proper learning, but also lead to the delivery of other goals. Also, due to the significant role of these students in the healthcare system, it is necessary to hold practical and theoretical exams of this course before entrance of students to the labor market in order to prevent the probable detrimental impacts on the healthcare system

Evaluation of a PCR Assay to Detect Enterococcus faecalis in Blood and Determine Glycopeptides Resistance Genes: Van A and Van B

Background: Bacteremia due to Enterococcus faecalis is usually caused by strains resistant to most antibiotics. Effective management of the disease is dependent on rapid detection and characterization of the bacteria, and determination its sensitivity pattern to antimicrobial drugs. The aim of this study was to investigate a more rapid and reliable assay for simultaneous diagnosis of enterococcal bacteremia and its sensitivity pattern to antimicrobial drugs. Methods: Several bacterial suspensions with different content of two standard strains of Enterococcus faecalis resistant to vancomycin were used for inoculation to defibrinated sheep blood samples. PCR and routine assay was performed on all blood samples with different bacterial content.Results: Routine assay and PCR for all inoculated blood samples with ≥5 cfu/ml was positive. Mean time for PCR and routine assays was 10 hours and 5 days, respectively. Conclusion: PCR is a more rapid and sensitive assay for simultaneous detection and characterization for Enterococcus faecalis, and determination of its sensitivity pattern to vancomycin

Construction, expression, purification and characterization of secretin domain of PilQ and triple PilA-related disulfide loop peptides fusion protein from Pseudomonas aeruginosa

Objective(s): Infection with Pseudomonas aeruginosa has been a long-standing obstacle for clinical therapy due to the complexity of the genetics and pathogenesis, as well for widespread resistance to antibiotics, thus attaching great importance to explore effective vaccines for prevention and treatment. This paper focuses on the introduction of novel Pseudomonas aeruginosa type IV pili (T4P)-based fusion protein containing the secretin domain of PilQ and tandem PilA-related peptides. Materials and Methods: We surveyed the expression of the PilQ380-705-PilA fusion protein in-frame with pET26b vector in which a rigid linker was used between two polypeptides and flexible linkers were inserted between the three tandem repeats and each pilA domains. The  transformants were  expressed in Escherichia coli BL21. The reactivity of specific antisera to the fusion protein was assessed by ELISA. The biological activities of this candidate vaccine were evaluated by western blotting, opsonophagocytosis, and twitching inhibition assays. Results: The fusion protein was purified in high yield by osmotic shock method using HisTrap affinity column. The protein was confirmed by immunoblot analysis. The checkerboard titration showed that the optimal dilution of the antibody to react with antigen is 1:128. Results of opsonophagocytosis assay revealed that the antibodies elevated to the fusion protein promoted phagocytosis of the PAO1 and 6266E strains, so that the twitching immobilization test confirmed these results. Conclusion: Due to excellent killing activity mediated by opsonic antibodies and efficient immobilization of the strains, it seems that PilQ380-705-PilA fusion protein could be a reliable candidate vaccine against P. aeruginosa infection

Evaluation of type IV pilin sub groups in Pseudomonas aeruginosa isolated from environmental samples, cystic fibrosis and burn patients

Background and Aim: Type IV pilin molecule in Pseudomonas aeruginosa with wide functions, has important role in the diversity of the bacterial genome.  According to the latest classification, Type IV pilin is divided to two main subtypes; IVa, IVb. The major subunit encoding Type IV pilin subtypes; IVa, IVb is pilA and pilS2 genes respectively which serve as a marker for the detection of the Type IV pilin subtypes. The purpose of the current study was to evaluate the frequency of pilA and pilS2 gene in cystic fibrosis, burns, and environmental isolates. Materials and Methods: The samples for P.aeruginosa were collected from cystic fibrosis, burns, and environment wastewater during the April 2013 to December 2013. Samples were cultured and identified using microbial and biochemical methods. DNA of isolates was extracted by commercial kit. PCR was performed using specific primers. Statistical analysis was done using SPSS 17.0 software. Results: A total of 100 P.aeruginosa isolates were collected; 30 cystic fibrosis, 30 burn, 40 environmental. The prevalence of the  pilA gene were 63.3% , 56.7% and 45/2%  for cystic fibrosis, for burns  and environmental strains . The PilS2 gene frequency was 57.5% of the environmental isolates, 67.5% of cystic fibrosis strains and 73.3 % of the isolates were burned. Conclusions: Our study showed that the frequency of P.aeruginosa T4P major pilin subunits in our P. aeruginosa population was high. The incidence of pilS2 gene was greater than pilA and was more frequent in Pseudomonas aeruginosa isolated from hospitalized burn patients