A Short Introduction to Bacteriophages

First discovered in the 19th century, bacteriophages (phages) are bacterial viruses and the most widespread entities on earth. Phages have multiple important roles in maintaining the bacterial population, carbon cycling, bacterial pathogenicity, and bacterial evolution. They can be used to develop DNA and protein vaccines, novel antibiotics and antiviral drugs, and phage therapy. The International Committee on Taxonomy of Viruses categorizes phages in two major orders of Caudovirales and Ligamenvirales, including five families, nine subfamilies, 145 genera, and 684 species. The most widespread families in nature are Siphoviridae, Myoviridae, Podoviridae, and Inoviridae. Phages are morphologically categorized in two major categories of tailed and polyhedral, filamentous, or pleomorphic phages. They can have either a single- or double-strand DNA or RNA genome. Phages are important for transferring mobile genetic elements, such as virulence genes and antimicrobial resistance determinants to bacteria by transduction, and have been used to treat bacterial infections. In conclusion, phages are important entities because of their roles in bacterial metabolism and surveillance in nature. Further studies can help usobtain a better understanding of the phage mechanism in bacterial evolution.Highlights Bacteriophages or phages are bacterial viruses with prokaryotes invasion ablility.Bacteriophage genes include lysis, replication, regulation, packaging, structural, antimicrobial resistance and housekeeping genes.Bacteriophages are important agents in transduction of mobile genetic elements to bacteria.One of the most interesting areas of the phage research can be its treatment application

Leptospirosis in Slaughterhouse Personnel: A Seroepidemiologic Study Using Microscopic Agglutination Test

Background and Objective: Meat can be contaminated by Leptospira species. This bacterial pathogen causes severe leptospirosis disease in humans and animals. The major aims of this study were to assess seroepidemiological prevalence of leptospirosis in employees of a slaughterhouse in Guilan Province, Iran, using microscopic agglutination test and further investigate the positive samples using nested polymerase chain reaction method. Material and Methods: In this study, 150 employees of a slaughterhouse in Guilan Province, Iran, were participated after completing written consents and personal questionnaires. This sample size was calculated based on the mean prevalence of the pathogen in the region. After assessing sera of the participants for Leptospira antibody using microscopic agglutination test, urine samples were collected from the positive participant for further assessments using nested polymerase chain reaction. Results and Conclusion: Based on the results, microscopic agglutination test was positive for 10.7% of the participants. However, Nested-PCR was negative for the positive microscopic agglutination tests on sera collected from the participants with antibodies against Leptospira antigens. The current results demonstrate that Leptospira can occur in asymptomatic humans in slaughterhouses and highlight the high potential of the disease transmission to humans in the province. Therefore, further extended control and prevention measures for slaughterhouse workers are recommended to guarantee the food safety. Conflict of interest: The authors declare no conflict of interest

Comparison of Multiple Tube Fermentation and Polymerase Chain Reaction Methods for the Detection of Coliforms in Freshwater

Background and objective: Detection of microbial pathogens in water is one of the major health issues. Escherichia coli species are used as indicators of fecal contamination in water microbial detection. In this study, efficacies of two methods of multiple tube fermentation and polymerase chain reaction have been compared for the detection of coliforms (especially Escherichia coli) in water.Material and methods: To compare multiple tube fermentation and polymerase chain reaction methods, 15 water samples were collected from five different sources (three gutter, six well, three tap and three bottled mineral water samples). The samples were cultured in lactose broth media to achieve the most probable number of bacteria. Furthermore, acetate cellulose filter method was used for the bacterial DNA extraction to investigate lacZ (indicating the presence of coliforms) and uidA (indicating the presence of Escherichia coli) genes. Results and conclusion: Based on the results of multiple tube fermentation, eight (53.3%) and six (40%) samples were contaminated with coliforms and Escherichia coli, respectively. Furthermore, polymerase chain reaction results showed that ten (66.7%) and eight (53.3%) samples contained coliforms and Escherichia coli, respectively. Results have suggested that polymerase chain reaction is much faster, more accurate and more sensitive than traditional methods (e.g. multiple tube fermentation) for the detection of coliform contaminated water. Moreover, several types of bacteria can be tracked simultaneously by M-PCR.Conflict of interest: The authors declare no conflict of interest

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 vancomycin-resistant 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

Designing a Multiple-Epitope Vaccine Candidate against Leishmania major and Leishmania infantum for Monocyte-Derived Exosome Preparation

Background: Leishmania is a vector-borne protozoon, which causes visceral, cutaneous and mucocutaneous leishmaniosis in human and animals. Monocyte-derived exosome vaccines can be used as prophylaxis and immunotherapy strategies. The aim of this study was to design a multiple-epitope candidate vaccine using leishmaniolysin (GP63) and rK39 proteins against Leishmania major and L. infantum for monocyte-derived exosome preparation. Methods: This study was carried out in Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran, 2023–2024. Effective immunodominant epitopes were selected from two antigenic proteins of GP63 and rK39 using various immunoinformatics and bioinformatics approaches. Vibrio cholerae β-subunit was used as an adjuvant to stimulate immune responses. Then, appropriate linkers were selected for the fusion of epitopes. The 3D model of candidate vaccine was predicted and validated. Results: This designed candidate vaccine could effectively be used as a prophylaxis strategy against leishmaniosis. Conclusion: A candidate vaccine was designed using bioinformatic and immunoinformatic studies with virtual acceptable quality; however, effectiveness of this vaccine should be verified through further in-vitro and in-vivo studies

Bacterial community survey of sediments at Naracoorte Caves, Australia

Bacterial diversity in sediments at UNESCO World Heritage listed Naracoorte Caves was surveyed as part of an investigation carried out in a larger study on assessing microbial communities in caves. Cave selection was based on tourist accessibility; Stick Tomato and Alexandra Cave (> 15000 annual visits) and Strawhaven Cave was used as control (no tourist access). Microbial analysis showed that Bacillus was the most commonly detected microbial genus by culture dependent and independent survey of tourist accessible and inaccessible areas of show (tourist accessible) and control caves. Other detected sediment bacterial groups were assigned to the Firmicutes, Actinobacteria and Proteobacteria. The survey also showed differences in bacterial diversity in caves with human access compared to the control cave with the control cave having unique microbial sequences (Acinetobacter, Agromyces, Micrococcus and Streptomyces). The show caves had higher bacterial counts, different 16S rDNA based DGGE cluster patterns and principal component groupings compared to Strawhaven. Different factors such as human access, cave use and configurations could have been responsible for the differences observed in the bacterial community cluster patterns (tourist accessible and inaccessible areas) of these caves. Cave sediments can therefore act as reservoirs of microorganisms. This might have some implications on cave conservation activities especially if these sediments harbor rock art degrading microorganisms in caves with rock art

The Larval Stages of Echinostoma spp. in Freshwater Snails as the First and Second Intermediate Hosts in Gilan and Mazandaran Provinces, Northern Iran

Background: Identification of the larval stages of Echinostoma spp. in freshwater snails is an essential guide to continue monitoring the possibility of their transmission and the potential of echinostomiasis in areas where trematodes are the primary agent of parasitic diseases. The aim of this study was investigate Echinostoma using morphological and molecular techniques.Methods: The study was conducted in Gilan and Mazandaran Provinces, northern Iran, from April 2019 to October 2021. Overall, 5300 freshwater snails were randomly collected and were identified using external shell morphology. Meanwhile, snails infected with trematodes were studied via shedding and dissecting methods. Larvae stages of Echinostoma were identified and the genomic DNA of the samples was extracted. The PCR amplification of the ITSI gene was carried out for 17 isolates and products were sequenced. Seven sequences were deposited in GenBank.Results: Totally, 3.5% of snails containing three species (Stagnicola sp., Radix sp. and Planorbis sp.) were infected with two types of cercaria, E. revolutum with 37 and Echinostoma sp. with 45 spines in the collar. Moreover, 35% of the snails were infected with Echinostoma spp. metacercaria. Phylogenetic analysis illustrated that isolates were included in two ITSI haplogroups. Conclusion: Results showed the potential hazard of a zoonotic parasite as Echinostoma in northern Iran. The potential of disease environmental relationship investigation and resource control optimization is necessary for effective disease prevention and health management

Bacteriophages: Foes or Friends? Bacteriophages: Foes or Friends?

HIGHLIGHTS•Bacteriophages are known for their roles in rapid development of the bacterial evolution and transfer of various genes.•Safety issues have always been a great concern since primary uses of bacteriophages in medicine.•Comprehensive studies are necessary to ensure safe uses of bacteriophages in medicine

Novel Therapeutic Methods Replacing Current Ones

With the advancements of science in recent years, novel therapeutic methods havebeen developed to treat microbial infections and improve medical performances. Thesenovel methods are more accurate than the old ones; therefore, they are more effective.Technically, these methods may revolutionize science in the future. Some of thesenew therapies include phage therapy, precision medicine, next-generation sequencing,picotechnology, the use of recombinant proteins, microchips, and robotic surgery, eachof which will in turn surprise the medical world. Although some of these treatments havebeen used in the past, researchers are now paying more attention to them because not onlythese newer methods are more accurate and efficient, but many of the older treatments,such as antibiotics, because of the increasing rate of the antibiotic resistance, are graduallylosing its popularity. In this letter, some of the latest innovative medical therapies havebeen discussed; which you will hear more about soon