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Aspergillus fumigatus causes a fatal infection particularly among immunocompromised individuals. Nowadays herbal and medicinal essential oils play a vital role as an alternative safe medication. Zataria multiflora Boiss essential oils have antifungal activities mainly on the expression of some gene required for fungal survival. The main objective of the study was evaluation of antifungal effects of Z. multiflora Boiss extract against A. fumigatus AfS35 strain. The strain was obtained from department of biology, Baghdad University. Various concentrations (10-300mg/mL) of Z. multiflora Boiss extract were prepared and the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) were determined using micro-broth dilution method. The expression of crzA and rpdA genes was evaluated using the quantitative real-time PCR (RT-qPCR) technique. The concentrations ≥100mg/mL of extract inhibited the fungal growth which was non-toxic to normal cell line (MIC=100mg/mL and MFC=150mg/mL). The combination of 50mg/mL of extract plus each of amphotericin B (10mg/ml) and nystatin (10mg/mL) significantly decreased the MIC level (p

Pseudomonas aeruginosa (P. aeruginosa) places among major opportunistic nosocomial pathogen which has developed extensive drug resistance. Due to uncontrolled consumption of antibiotics, multidrug-resistant (MDR) P. aeruginosa species are increasingly isolated from various settings of hospitals globally. This research aimed to determine the genes reproducing blaOXA-48, blaIMP-1, blaVIM-1 and blaNDM-1 metallo beta lactamase (MBL) genes from MDR P. aeruginosa isolates. Herein, the isolates of 200 P. aeruginosa have been obtained from microbiology laboratory of burn ward. The antibiotic susceptibility profile was using Disc Diffusion Method (DDM and in compliance with CLSI (Clinical and Laboratory Standards Institute) advice. Study of MBL-bearing strains and the existence of encoding genes was specified by means of polymerase chain reaction. In addition, pulsed field gel electrophoresis (PFGE) is performed for typing. In this study, 124 (62%) were extended spectrum β-lactamase producer and 51 (25.5%) were MBL producers. Moreover, 148 (74%) isolates were MDR-P. aeruginosa. Additionally, 42 (21%), 21 (10%), 10 (5%) and 2 (1%) isolates carried the blaIMP-1, blaOXA-48, blaVIM-1 and blaNDM-1 genes, respectively. The PFGE showed no genetic relationships among isolates. The study observed high rate of MDR P. aeruginosa in hospital settings, though not being outbreak, which nearly half of them carried carbapenemase enzymes. Therefore, the proper control of related infections and appropriate prescription and consumption of antibiotics is essential.

Background: Dermatophytosis still remains a major public health concern worldwide, particularly in developing countries. This study was undertaken to determine the etiological and epidemiological factors of dermatophyte infections in Tehran, Iran. Methods: A total of 1530 patients clinically suspected of cutaneous fungal infections were examined in two hospitals over a period of 10 years (2010–2020). Samples were analyzed using direct microscopic examination and culture. Data regarding age, gender, and clinical manifestations were also recorded. Results: Out of 1530 cases examined, dermatophytes were detected in 493 (32.2%) patients. Of these patients, 288 (58.4%) were males and 205 (41.6%) were females. The most affected age group was the 25–44 years old (31.6%). Tinea corporis (n=134) was the most prevalent type of ringworm, followed by tinea cruris (n=131), tinea pedis (n=90), tinea manuum (n=65), tinea unguium (n=29), tinea faciei (n=20), tinea capitis (n=18), and tinea barbae (n=2). Both tinea cruris (P

The continuing emergence or re-emergence of vector-borne zoonotic Q fever (caused by Coxiella burnetii) and Crimean Congo hemorrhagic fever (CCHF, caused by Orthonairovirus) include indispensable extraordinary threat around the world. Low infectious dose and long-term environmental residence are major risks. Wildlife and domestic livestock act as hosts or reservoirs of the CCHF virus and ticks are carriers. The disease also poses a threat to public health services owing to its epidemic potential, high case fatality ratio (up to 40%) as well as difficulties in treatment, prevention, and control. Q fever is another zoonotic febrile disease mainly affecting workers involved in farming livestock. The causative agent of Q fever causes abortion in livestock. The pathogen is shed in large numbers in the waste of infected animals (amniotic fluids and placenta during parturition) and is transmitted by inhalation of contaminated aerosols. Vaccination is the most effective way of protecting against Q fever. The main way to prevent Q fever is to avoid contact with animals, especially while animals are giving birth, or consumption of unpasteurized milk and contaminated dairy products. Due to the increasing importation of livestock to meet the growing demand for dairy and meat products, new diseases are likely to be introduced. In our growing globalized world, where trade between countries increases, it is necessary to conduct more research on zoonotic diseases and to monitor any possible disease introduction to new areas. A continuing surveillance program and pathogen testing are important in tracking the emergence of new pathogens.

Breast feeding has critical effects on the newborns and either mother’s health. Some of such health-improving effects of the mother’s milk is associated with the beneficial microbes, lactic acid bacteria (LAB), which are normally present in the mother’s milk. Thus, human milk-associated lactobacilli were isolated in this study and some of their probiotic properties was investigated. Afterwards, Lactobacillus strains were screened for low pH and bile acids tolerance. Molecular identification was carried out using 16SrDNA and polymerase chain reaction (PCR). Antibiotic resistance was evaluated with disk diffusion assay and the inhibitory effect of isolates on pathogenic bacteria was examined with well assay and zone inhibition. Isolation experiments resulted in 122 human milk- associated lactobacilli belonging to 12 species. The most dominant species was Lactobacillus casei followed by Lactobacillus fermentum, Lactobacillus plantarum and Lactobacillus gasser, respectively. Screening for probiotic properties showed that 19 isolates, belonging to, Lactobacillus, have interesting probiotic characteristics. The most prevalent antibiotic resistance was observed in case of vancomycin (63.15%) and no drug resistance was detected for chloramphenicol, penicillin, rifampin (0%). Three Lactobacillus strains, designated as L4, L14 and L16, were found as potential probiotic strains since they have indicated promising inhibitory effects against the studied pathogenic bacterial strains. Our results shed light on the considerable diversity of lactobacilli in human breast milk. Furthermore, the candidate probiotic strains detected in this research might be used as potential probiotic strains. Key words: Breast milk, Lactobacillus, probiotics, inhibitory effect, polymerase chain reaction.

Background. Investigating the viability and proliferative rates of fibroblast cells on human amniotic membrane (HAM) as a scaffold will be an important subject for further research. The aim of this study was to assess the fibroblast viability seeded on acellular HAM, since foreskin neonatal allogenic fibroblasts seeded on HAM accelerate the wound healing process. Methods. Fibroblasts were retrieved from the foreskin of a genetically healthy male infant, and we exploited AM of healthy term neonates to prepare the amniotic scaffold for fibroblast transfer. After cell culture, preparation of acellular HAM, and seeding of cells on HAM based on the protocol, different methods including 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), 4 ′ ,6-Diamidino-2-phenylindole dihydrochloride (DAPI), and propidium iodide (PI) staining were employed for assessment of fibroblast viability on HAM. Results. Based on the results obtained from the DAPI and PI staining, the percentage of viable cells in the former staining was clearly higher than that of the dead cells in the latter one. The results of DAPI and PI staining were in accordance with the findings of MTT assay, confirming that fibroblasts were viable and even proliferate on HAM. Conclusion. Our findings showed the viability of fibroblasts seeded on the acellular HAM using MTT assay, DAPI, and PI staining; however, this study had some limitations. It would be an interesting subject for future research to compare the viability and proliferation rate of fibroblasts seeded on both cellular and acellular HAM.

Keloids are abnormal fibroproliferative scars with aggressive dermal growth expanding beyond the borders of the original injury. Different therapeutic modalities, such as corticosteroids, surgical excision, topical silicone gel sheeting, laser therapy, cryotherapy, photodynamic therapy and radiotherapy, have been used to treat keloids; however, none of these modalities has proven completely effective. Recently, researchers have devised several promising anti-keloid therapies including anti-hypertensive pharmaceuticals, calcineurin inhibitors, electrical stimulation, mesenchymal stem cell therapy, microneedle physical contact and ribonucleic acid-based therapies. The present review summarises emerging and novel treatments for keloids. PubMed® (National Library of Medicine, Bethesda, Maryland, USA), EMBASE (Elsevier, Amsterdam, Netherlands) and Web of Science (Clarivate Analytics, Philadelphia, Pennsylvania, USA) were searched for relevant literature published between January 1987 to June 2020. A total of 118 articles were included in this review. A deeper understanding of the molecular mechanisms underlying keloid scarring pathogenesis would open further avenues for developing innovative treatments. KEYWORDS Keloid; Treatment; Fibroblast; Scar; Dermatology.

Background: Quinolone resistant Salmonella serotypes have been reported in recent years and have become increasingly widespread worldwide. Objectives: We evaluated the molecular mechanism of quinolone resistance in non-typhoidal Salmonella strains isolated from clinical samples in Tehran, Iran. Methods: The present study included the Salmonella isolates originated from hospitalized individuals and outpatients in Tehran, Iran. Serotyping of nalidixic acid-resistant Salmonella isolates was done by slide agglutination method. Then, the quinolone resistance-determining region (QRDR) of topoisomerase gene gyrA and the plasmid-mediated quinolone resistance (PMQR) determinants were detected using the polymerase chain reaction (PCR) method. Restriction fragment length polymorphism (RFLP) analysis was also employed to determine the possible mutation in the gyrA gene of those strains. Mutant strains were detected by enzymatic digestion, and their PCR products were sequenced immediately. Results: Amongst 141 isolates, 60% showed nalidixic acid resistance, whereas none of them were ciprofloxacin-resistant. The commonly prevalent serotypes were S. Enteritidis and S. Infantis. Of 85 nalidixic acid-resistant strains, 17 (20%) isolates harbored the qnrS gene. However, PCR analysis of the quinolone-resistant strains did not detect qnrA and qnrB genes. PCR-RFLP and sequencing analysis of the QRDRs of the gyrA gene indicated that 16 (18.8%) isolates had mutant patterns, and the most common point mutation was serine to phenylalanine at position 83. Conclusions: Our results demonstrated that point mutations in gyrA and the existence of plasmid-mediated gene qnrS were important mechanisms of quinolone resistance in non-typhoidal Salmonella strains isolated from human origin. Other alternative mechanisms of resistance, such as alterations in the expression of efflux pumps, should be studied to provide greater insight into the molecular mechanism of quinolone-resistant non-typhoidal Salmonella isolates.

Many fungal diseases remain poorly addressed by public health authorities, despite posing a substantial threat to humans, animals, and plants. More worryingly, few classes of anti-fungals have been developed to combat fungal infections thus far. These medications also have certain drawbacks in terms of toxicity, spectrum of activity, and pharmacokinetic properties. Hence, there is a dire need for discovery of novel anti-fungal agents. Melittin, the main constituent in the venom of European honeybee Apis mellifera, has attracted considerable attention among researchers owing to its potential therapeutic applications. To our knowledge, there has been no review pertinent to anti-fungal properties of melittin, prompting us to synopsize the results of experimental investigations with a special emphasis upon underlying mechanisms. In this respect, melittin inhibits a broad spectrum of fungal genera including Aspergillus, Botrytis, Candida, Colletotrichum, Fusarium, Malassezia, Neurospora, Penicillium, Saccharomyces, Trichoderma, Trichophyton, and Trichosporon. Melittin hinders fungal growth by several mechanisms such as membrane permeabilization, apoptosis induction by reactive oxygen species-mediated mitochondria/caspase-dependent pathway, inhibition of (1,3)-β-d-glucan synthase, and alterations in fungal gene expression. Overall, melittin will definitely open up new avenues for various biomedical applications, from medicine to agriculture. • Venom-derived peptides have potential for development of anti-microbial agents. • Many fungal pathogens are susceptible to melittin at micromolar concentrations. • Melittin possesses multi-target mechanism of action against fungal cells.

Despite tremendous advances in the development of anti-viral therapeutics, viral infections remain a chief culprit accounting for ongoing morbidity and mortality worldwide. Natural products, in particular animal venoms, embody a veritable cornucopia of exotic constituents, suggesting an immensurable source of anti-infective drugs. In this context, melittin, the principal constituent in the venom of the European honeybee Apis mellifera, has been demonstrated to exert anti-cancer, anti-inflammatory, anti-diabetic, anti-infective, and adjuvant properties. To our knowledge, there is no review appertaining to effects of melittin against viruses, prompting us to synopsize experimental investigations on its anti-viral activity throughout the past decades. Accumulating evidence indicates that melittin curbs infectivity of a diverse array of viruses including coxsackievirus, enterovirus, influenza A viruses, human immunodeficiency virus (HIV), herpes simplex virus (HSV), Junín virus (JV), respiratory syncytial virus (RSV), vesicular stomatitis virus (VSV), and tobacco mosaic virus (TMV). However, medication safety, different routes of administrations, and molecular mechanisms behind the anti-viral activity of melittin should be scrutinized in future studies.

Helicobacter pylori (H. pylori) causes gastric mucosa inflammation and gastric cancer mostly via several virulence factors. Induction of proinflammatory pathways plays a crucial role in chronic inflammation, gastric carcinoma, and H. pylori pathogenesis. Herbal medicines (HMs) are nontoxic, inexpensive, and mostly anti-inflammatory reminding meticulous emphasis on the elimination of H. pylori and gastric cancer. Several HM has exerted paramount anti-H. pylori traits. In addition, they exert anti-inflammatory effects through several cellular circuits such as inhibition of 5'-adenosine monophosphate-activated protein kinase, nuclear factor-κB, and activator protein-1 pathway activation leading to the inhibition of proinflammatory cytokines (interleukin 1α [IL-1α], IL-1β, IL-6, IL-8, IL-12, interferon γ, and tumor necrosis factor-α) expression. Furthermore, they inhibit nitrous oxide release and COX-2 and iNOS activity. The apoptosis induction in Th1 and Th17-polarized lymphocytes and M2-macrophagic polarization and STAT6 activation has also been exhibited. Thus, their exact consumable amount has not been revealed, and clinical trials are needed to achieve optimal concentration and their pharmacokinetics. In the aspect of bioavailability, solubility, absorption, and metabolism of herbal compounds, nanocarriers such as poly lactideco-glycolide-based loading and related formulations are helpful. Noticeably, combined therapies accompanied by probiotics can also be examined for better clearance of gastric mucosa. In addition, downregulation of inflammatory microRNAs (miRNAs) by HMs and upregulation of those anti-inflammatory miRNAs is proposed to protect the gastric mucosa. Thus there is anticipation that in near future HM-based formulations and proper delivery systems are possibly applicable against gastric cancer or other ailments because of H. pylori.

The emergence of antibiotic-resistant bacteria, dubbed superbugs, together with relative stagnation in developing efficient antibiotics has led to enormous health and economic problems, necessitating the need for discovering and developing novel antimicrobial agents. In this respect, animal venoms represent a rich repertoire of pharmacologically active components. As a major component in the venom of European honeybee Apis mellifera, melittin has a great potential in medical applications. In this mini-review, we summarize a multitude of studies on anti-bacterial effects of melittin against planktonic and biofilm-embedded bacteria. Several investigations regarding synergistic effects between melittin and antibiotics were also described. On the whole, the properties of melittin can open up new horizons in a range of biomedical areas, from agriculture to veterinary and clinical microbiology.

Protozoan diseases such as malaria, leishmaniasis, Chagas disease, and sleeping sickness still levy a heavy toll on human lives. Deplorably, only few classes of anti-protozoan drugs have thus far been developed. The problem is further compounded by their intrinsic toxicity, emergence of drug resistance, and the lack of licensed vaccines. Thus, there is a genuine exigency to develop novel anti-protozoan medications. Over the past years, melittin, the major constituent in the venom of European honeybee Apis mellifera, has gathered the attention of researchers due to its potential therapeutic applications. Insofar as we are aware, there has been no review pertinent to anti-protozoan properties of melittin. The present review outlines the current knowledge about anti-protozoan effects of melittin and its underlying mechanisms. The peptide has proven to be efficacious in killing different protozoan parasites such as Leishmania, Plasmodium, Toxoplasma, and Trypanosoma in vitro. Apart from direct membrane-disruptive activity, melittin is capable of destabilizing calcium homeostasis, reducing mitochondrial membrane potential, disorganizing kinetoplast DNA, instigating apoptotic cell death, and induction of autophagy in protozoan pathogens. Emerging evidence suggests that melittin is a promising candidate for future vaccine adjuvants. Transmission-blocking activity of melittin against vector-borne pathogens underscores its potential utility for both transgenic and paratransgenic manipulations. Nevertheless, future research should focus upon investigating anti-microbial activities of melittin, alone or in combination with the current anti-protozoan medications, against a far broader spectrum of protozoan parasites as well as pre-clinical testing of the peptide in animal models.

Over the past years, short anti-microbial peptides have drawn growing attention in the research and trade literature because they are usually capable of killing a broad spectrum of pathogens by employing unique mechanisms of action. This study aimed to evaluate the anti-bacterial effects of a previously designed peptide named PVP towards the clinical strains of methicillin-resistant Staphylococcus aureus (MRSA) in vitro. Secondary structure, cytotoxicity, and membrane-permeabilizing effects of the peptide were also assessed. PVP had a tendency to adopt alpha-helical conformation based upon structural predictions and circular dichroism spectroscopy (in 50% trifluoroethanol). The peptide showed MIC values ranging from 1 to 16 µg/mL against 10 strains of MRSA. In contrast to ciprofloxacin and gentamicin, PVP at sub-lethal concentration (1 µg/mL) did not provoke the development of peptide resistance after 14 serial passages. Remarkably, 1 h of exposure to 4 × MBC of PVP (8 µg/mL) was sufficient for total bacterial clearance, whereas 4 × MBC of vancomycin (8 µg/mL) failed to totally eradicate bacterial cells, even after 8 h. PVP showed negligible cytotoxicity against human dermal fibroblasts at concentrations required to kill the MRSA strains. The results of flow cytometric analysis and fluorescence microscopy revealed that PVP caused bacterial membrane permeabilization, eventually culminating in cell death. Owing to the potent anti-bacterial activity, fast bactericidal kinetics, and negligible cytotoxicity, PVP has the potential to be used as a candidate antibiotic for the topical treatment of MRSA infections.

Climate changes have a profound effect on human health, especially when infectious diseases are concerned. Variable factors including temperature, precipitation, and relative humidity directly influence the magnitude and frequency of water-borne pathogen transfers. In this study, we determined the long-term temporal trends and seasonal patterns of shigellosis and evaluated the effects of demographic and climatic factors on its incidence in Yazd province, Iran, during 2012 through 2015. The incidence of shigellosis was highest among patients in the age group of 6–20 years and peaked in every summer of the years studied, especially during August. Furthermore, there was a significant association between climatic variables (such as monthly temperature, humidity, and atmospheric dust) and the incidence of shigellosis. However, contrary to expectations, rainfall did not affect incidence of the disease. The transmission of Shigella to humans is a complex ecological process. Socio-economic factors and lifestyle behaviours need to be addressed in future studies.

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.

Background: Pathogenicity O island 122 (OI-122) associated with the severity of Enteropathogenic Escherichia coli (EPEC) disease. Objectives: The aim of this study was the characterization of OI-122 in Iranian EPEC isolates. Methods: The distribution patterns of OI-122 were investigated in 42 EPEC strains by detection of OI-122 genes and serogrouping, multi locus VNTR (MLVA) typing, and phylogenetic grouping. Results: The complete OI-122 was identified in 18.75% of tEPEC and in 3.8% of aEPEC strains, an incomplete OI-122 with various combinations of genes was found in 75% of tEPEC and 30.76% of strains aEPEC, and OI-122 genes were absent in 6.25% of tEPEC and 65.3% of aEPEC strains. nleB (52.4%) was the most frequently detected, and the prevalence of pagC, efa1/lifA, and sen genes were 19%, 16.7%, and 14.3%, respectively. The most common phylogenetic group among tEPEC and aEPEC strains were B1 (68.75% and 80.76%, respectively). The common serogroups among EPEC isolates were O128, O111, O55, O127, and O44, and 45.2% of the isolates were untypeable. Forty-one MLVA types among 42 EPEC strains were classified into 7 clonal complexes. Conclusions: The diverse distribution of OI-122 genes among MLVA clonal groups provides evidence for dynamic evolution regarding the OI-122 pathogenicity island in tEPEC and aEPEC strains. The results also indicate that the acquisition of OI-122 gene contents occurs in a modular manner.

Bacterial biofilms are multicellular aggregates enclosed in a self-created biopolymer matrix. Biofilm-producing bacteria have become a great public health problem worldwide because biofilms enable these microorganisms to evade several clearance mechanisms produced by host and synthetic sources. Over the past years, different flavonoids including quercetin have engrossed considerable interest among researchers owing to their potential anti-biofilm properties. To our knowledge, there is no review regarding effects of quercetin towards bacterial biofilms, prompting us to summarize experimental evidence on its anti-biofilm properties. Quercetin inhibits biofilm development by a diverse array of bacterial pathogens such as Enterococcus faecalis, Staphylococcus aureus, Streptococcus mutans, Escherichia coli, and Pseudomonas aeruginosa. Prevention of bacterial adhesion, suppression of quorum-sensing pathways, disruption or alteration of plasma membrane, inhibition of efflux pumps, and blocking nucleic acid synthesis have been documented as major anti-biofilm mechanisms of quercetin. Overall, anti-biofilm activity of quercetin can open up new horizons in a wide range of biomedical areas, from food industry to medicine.

Salmonella is an important cause of food-borne infection worldwide. Detection of outbreaks caused by Salmonella spp. relies on suitable and robust methods for genotyping. Little is known about the genetic diversity of the Salmonella enterica subspecies enterica serotype Infantis strains isolated from human sources in Iran. In this study, 40 isolates of S. Infantis, which were previously recovered from patients with gastroenteritis or diarrhea in Tehran between years 2007 and 2009, were subjected to multiple-locus variable-number of tandem repeat (VNTR) analysis (MLVA), pulsed-field gel electrophoresis (PFGE), and ERIC-PCR. Using MLVA method, 31 types were identified. The MLVA clustering of the isolates by the unweighted pair group method with arithmetic mean (UPGMA) revealed the presence of two major clusters. The discriminatory power of MLVA was superior to that of PFGE and ERIC-PCR. Overall, our data showed that MLVA assay could effectively differentiate closely related strains. It is technically simple and inexpensive to perform. Furthermore, MLVA can be used as a helpful method for epidemiological investigations.

Klebsiella pneumoniae is one of the most important agents of community-acquired urinary tract infection (CA-UTI). In addition to extended-spectrum β-lactamases (ESBLs), a number of virulence factors have been shown to play an important role in the pathogenesis of K. pneumoniae, including capsule, siderophores, and adhesins. Little is known about the genetic diversity and virulence content of the CTX-M-15-producing K. pneumoniae isolated from CA-UTI in Iran. A total of 152 K. pneumoniae isolates were collected from CA-UTI patients in Tehran from September 2015 through April 2016. Out of 152 isolates, 40 (26.3%) carried blaCTX-M-15. PCR was performed for detection of virulence genes in CTX-M-15-producing isolates. Furthermore, all of these isolates were subjected to multiple-locus variable-number of tandem repeat (VNTR) analysis (MLVA). Using MLVA method, 36 types were identified. CTX-M-15-producing K. pneumoniae isolates were grouped into 5 clonal complexes (CCs). Of these isolates, mrkD was the most prevalent virulence gene (95%), followed by kpn (60%), rmpA (37.5%), irp (35%), and magA (2.5%). No correlation between MLVA types or CCs and virulence genes or antibiotic resistance patterns was observed. Overall, it is thought that CTX-M-15-producing K. pneumoniae strains isolated from CA-UTI have arisen from different clones.

Antimicrobial peptides are considered to be excellent templates for designing novel antibiotics because of their broad-spectrum antimicrobial activity and their low prognostic to induce antibiotic resistance. In this study, for the first time, a series of short hybrid antimicrobial peptides combined by different fragments of venom-derived alpha-helical antimicrobial peptides pEM-2, mastoparan-VT1, and mastoparan-B were designed with the intent to improve the therapeutic index of the parental peptides. Short hybrid antimicrobial peptides PV, derived from pEM-2 and mastoparan-VT1, was found to possess the highest antibacterial, hemolytic, and cytotoxic activity. Short hybrid antimicrobial peptides PV3, derived from pEM-2 and three fragments of mastoparan-VT1, showed more than threefold improvement in therapeutic index compared with parental peptides pEM-2 and mastoparan-VT1. PV had the highest antimicrobial activity in stability studies. Except BVP, designed based on all three parental peptides, the other short hybrid antimicrobial peptides at their minimal inhibitory concentration and 2× minimal inhibitory concentration required less than 120 and 60 min to reduce >3log10 the initial inoculum, respectively. All peptides had membrane-disrupting activity in a time-dependent manner. Collectively, this study highlights the potential for rational design of improved short hybrid antimicrobial peptides such as PV3 that was an ideal candidate for further assessment with the ultimate purpose of development of effective antimicrobial agents.

Antimicrobial peptides are attractive candidates for developing novel therapeutic agents, since they are lethal to a broad spectrum of pathogens and have a unique low tendency for resistance development. In this study, mechanism of action and in vitro anti-pseudomonal activity of previously designed short hybrid antimicrobial peptide PV3 were investigated. Compared to ceftazidime, PV3 had not only higher antibacterial activity but also faster bactericidal activity. PV3 reduced biofilm biomass and viability of biofilm embedded bacteria in a concentration-dependent manner. Although the antimicrobial activity of PV3 was reduced in Mueller-Hinton broth (MHB) containing human serum, it was still active enough to eradication of bacteria at low concentrations. Compared with standard condition (MHB only), there was no significant decrease in antibacterial activity of PV3 against P. aeruginosa strains under 150 mM NaCl (p = 0.615) and 1 mM MgCl2 (p = 0.3466). Fluorescence microscopy and field emission scanning electron microscopy further indicated that PV3 killed bacteria by disrupting the cell membrane. Since PV3 has potent anti-pseudomonal activity and has little cytotoxicity in vitro, it seems plausible that the peptide should be further investigated with animal studies to support future pharmacological formulations and potential topical applications.

Microbial water-borne diseases still affect developing countries and are major water quality concerns throughout the world. Routine culture-based methods of identifying bacterial pathogens in water sources are laborious and time-consuming. Recently, the use of molecular techniques such as the polymerase chain reaction (PCR) has provided rapid and highly promising detection methods. In this study, we developed two multiplex PCR assays for simultaneous detection of six water-borne bacteria. Two triplex PCR protocols were developed to detect six target genes. The first protocol targets uidA (Escherichia coli), int (Shigella spp.), and gyrB (Pseudomonas aeruginosa) genes, while invA (Salmonella spp.), ompW (Vibrio cholera), and lacZ (coliforms) were amplified by the second protocol. Specificity testing was carried out for 12 reference strains. Furthermore, the applicability of the multiplex PCR assays for detection of these bacteria was investigated for 52 surface water samples. The results indicated that all primer pairs showed specificities only for their corresponding target organisms. The detection sensitivity of both multiplex PCR assays was 3 × 102 − 3 × 103 colony forming units. The developed assays represent simple and efficient diagnostic procedures for co-detection of water-borne bacteria and have the potential to provide earlier warnings of possible public health threats and more accurate surveillance of these organisms.

Letter to the Editor

During the past decade, cationic antimicrobial peptides (CAPs) have gained particular interest among researchers, since they often display broad-spectrum antimicrobial activity and low possibility of resistance emergence. This study aimed to investigate in vitro effectiveness of Mastoparan-1 (MP-1), a tetradecapeptide CAP from hornet venom, against methicillin-resistant Staphylococcus aureus (MRSA) isolates. MP-1 had a high propensity to form alpha-helix based on structural predictions. MP-1 was found to possess strong antimicrobial activities and weak cytotoxic effects. Multiple treatments of MRSA with MP-1 at sub-lethal dose did not induce resistance. At 4 × minimum bactericidal concentration (MBC), MP-1 eradicated bacteria within 60 min, whereas vancomycin was unable to eradicate MRSA even after 480 min of exposure, highlighting rapid bactericidal kinetics of MP-1. Treatment of bacteria with 2 × MBC of MP-1 caused a time-dependent increase in orange/red fluorescence intensity. Compared with vancomycin, MP-1 significantly reduced biofilm formation and diminished both biofilm biomass and viability of biofilm-embedded bacteria in a concentration-dependent manner. Taken together, the current data reveal not only that MP-1 is a potent bactericidal and antibiofilm agent, but also that it is less likely to invoke antimicrobial resistance, reinforcing further studies concerning the therapeutic applications of MP-1.

Background: Uropathogenic E. coli (UPEC) is the primary cause of human urinary tract infections (UTIs) worldwide. Moreover, there has been renewed and growing interest in using older antibiotics for treatment, such as aminoglycosides. Objectives: The goal of this study was to determine the plasmid profile patterns of UPEC isolates harboring the aminoglycoside resistance gene aac(3)-IIa. Patients and Methods: A total of 276 uropathogenic E. coli (UPEC) samples were isolated from UTI patients at the Tehran heart cente rin Tehran, Iran. Antimicrobial susceptibility testing against five aminoglycosides was performed by the disk diffusion method, and the aac(3)-IIa gene was detected via PCR. Moreover, plasmid profiling was carried out on those UPEC isolates harboring the aac(3)-IIa gene. Finally, the similarities among these isolates were determined on the basis of their plasmid profiles. Results: The highest level of resistance was seen for tobramycin (24.6%), and the aac(3)-IIa gene was found in 51 isolates. Twentyseven different plasmid profiles were identified among the isolates harboring the aac(3)-IIa gene, with the 15 kb plasmid being the most common. Moreover, no significant correlation was found between the resistance patterns and the number of plasmids. The cluster analysis based on the plasmid profiles grouped the isolates into five different clusters, of which cluster one was the largest (containing 14 of 51 isolates). Conclusions: Our data suggest the monitoring of aminoglycoside resistance, and its consideration in the empirical therapy of UPEC infections.