ciamak ghazaei

The spectrum of diseases caused by intracellular bacterial pathogens (IBPs) is broad, ranging from life-threatening conditions such as tuberculosis to other infectious-transmitted diseases. Conventional antibiotic treatment faces challenges due to antibiotic resistance, host cell toxicity, and limited drug penetration. Despite the excellent ability of these perilous pathogens to modulate host cell biology, localize in, and multiply through targeting the key virulence factors, cell brings about auspicious maneuvers to combat pathogenic diseases and alleviate their significant global burden. Modulation and identification of molecules, pathways, and responses are the initial steps of targeted therapy, varying from disease to disease. This article explores the cutting-edge advancements in targeted therapy approaches. Innovations such as nanoparticlebased drug delivery systems, phage therapy, immunomodulation, and gene editing, which hold a promising future for overcoming the limitations of traditional treatment, are also discussed. Efficient delivery systems, drug optimizations, and inch-perfect distribution and retention of therapeutic agents are some of the determining factors in the success of targeted therapy for bacterial pathogens. The article also presents a novel application wherein filamentous phages are loaded as targets in nanocarriers for therapeutic purposes. The present challenges faced by the researchers, along with future directions for this field of medical science, are also outlined. Overall, the scope of this article involves the various strategies involved in targeted therapy, drug modulations, and limitations faced in our current approaches.

The Tol/Pal system is a group of complex proteins found in Gram-negative bacteria that has a crucial function in bacterial outer membrane development and safety. It is a promising target for potential antibacterial therapy. Initially, this Tol/Pal system was thought to be associated with the uptake of toxins such as colicins by Escherichia coli. However, the latest research has revealed that this system has much broader features beyond that. The system has been extensively studied, and this article discusses some of the conclusions drawn from those studies. Most significantly, the Tol/Pal system is a prerequisite for the pathogenicity of many Gramnegative bacteria, indicating that it has a remarkable role in how these bacteria cause diseases. Moreover, this system plays a vital role in the growth and overall fitness of specific pathogens. This indicates that it may be a promising target for growing antimicrobial therapies. Significantly, one of the proteins in this system, called Pal, is highly recognizable through the immune system and may trigger each of the adaptive and innate immune responses. A lot of these features make the Tol/Pal system an exciting area of research for the development of antibacterial therapies, in particular for dealing with stubborn infections caused by gram-negative pathogens, which are resistant to a couple of drugs. This paper offers an outline of the mechanisms of the Tol/ Pal system within the context of bacterial disease development and its potential utilization as a vaccine to counter respective bacterial infections.

Species Pseudomonas aeruginosa is a distinguished opportunistic nosocomial bacterium that is commonly dispersed in nature. A pathogen that causes a large range of infections i.e. chronic as well as acute, with considerable levels of mortality and morbidity. Infections of P. aeruginosa are extremely hard to eliminate because of the presence of several virulence determinants as well as the intrinsic resistance against antibiotics. The present study investigated the detection of the virulence genes by polymerase chain reaction (PCR) namely oprL and lasB in the P. aeruginosa that were isolated detection from both human and animal specimens. 120 specimens of P. aeruginosa including samples were then collected from hospitals and veterinary laboratories, from which 55 isolates of P. aeruginosa were identified and selected. Pseudomonas aeruginosa strains were present in 40% of animal sample isolates and 86% of human sample isolates. The PCR results showed that oprL genes were detected in 54.16% of isolates obtained from animal samples and 80.76% of isolates obtained from human samples. While, the lasB gene was present at 58.33% and 92.30% in the isolates obtained from animal and human samples, respectively. Our results also showed the coexistence of both virulence genes in 32.34% of animal sample isolates and 25.10% of human sample isolations. The detection of gene oprL and lasB by the PCR technique can be effectively used for the molecular-level identification of P. aeruginosa. The identification of such virulence genes in P. aeruginosa isolates suggests that these may be linked with varying degrees of the pathogenesis and inherent virulence in this pathogen.

Multi-drug-resistant (MDR) and extensively drug-resistant (XDR) bacteria are becoming a serious global health issue, which may soon become untreatable by clinicians. Since the invention of antibiotics, inappropriate consumption, non-prescribed drugs, overuse, and hoarding have caused the rapid emergence of MDR and XDR bacteria. The ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, and Enterobacter spp.) cause many nosocomial infections and thus escape the biocidal action of the antibiotic. Gram-positive and Gram-negative bacteria have acquired self-defense tools like ESBL (extended spectrum beta-lactamase), a mutation in porin genes, biofilm production, and many more to develop multi-drug resistance. Antimicrobial resistance (AMR) endangers patients' treatment as it causes high mortality and morbidity rates, economic loss of both patient and country, and prolonged hospital stay. To combat upcoming MDR and XDR bacteria, it is essential to design novel therapeutic techniques to eradicate such resistant bacteria via burgeoning technologies like nanoparticles, CRISPER-Cas9, genetic engineering, and synthetic biology.

Endothelial cells (ECs) that line the inner surface of blood vessels play a crucial role in maintaining healthy blood vessels and regulating consistent blood flow. EC dysfunction (ECD) is the improper functioning of ECs as a result of any modification or damage. Numerous health issues such as cardiovascular disease, hypertension, lightheadedness, exhaustion, diabetes, and the like could result from this. Both extrinsic and intrinsic factors may cause ECD. Many virus-induced hemorrhagic fevers, including dengue fever, Ebola, and Lassa fever, exhibit ECD. ECs maintain barrier functions by regulating immune cell interactions, homeostasis, and capillary permeability, and in viral infections, viral interaction alters these factors. These pathogens destroy ECs, leading to a loss of integrity in the blood vessels and increased permeability. Hemorrhagic fever can cause a wide range of symptoms such as fever, headache, muscle pain, weakness, exhaustion, bruises, bleeding, shock, and occasionally even the emergence of additional issues such as organ failure. Hemorrhagic fevers can be life-threatening if not treated promptly and correctly. Considering that ECD can be a silent condition, consultation with physicians about individuals’ risk factors and regular screenings to detect and prevent this condition is highly important. There is no specific antiviral treatment for most hemorrhagic fevers, but research is ongoing to develop effective treatments. This review will discuss the ECD due to viral interactions to cause hemorrhagic fevers, available treatments, and challenges associated with such viral hemorrhagic fevers (VHFs).

The objective of the present study was to assess the antibacterial and antibiofilm activities of Pediocin, a bacteriocin extracted from cheese, versus a subset of bacteria linked to foodborne diseases. The agar well diffusion method was used to evaluate the antibacterial activity of Pediocin. The results showed that Pediocin had a potent bactericidal effect against all the tested bacterial strains. The crystal violet staining method was used to assess Pediocin's antibiofilm efficacy, and the results showed that Pediocin significantly inhibited the development of biofilms by the tested bacterial strains. Investigating the effects of temperature, pH, and medium make-up improved Pediocin output. It was discovered that a temperature of 30 °C, a pH of 6.5, and a medium made up of tryptone, yeast extract, and glucose were the ideal conditions for the creation of pediocin. Pediocin demonstrated significant antibacterial activity against all the tested bacterial strains, with the highest activity against Staphylococcus aureus, Streptococcus pyogenes and Helicobacter pylori. The minimum inhibitory concentration (MIC) values of Pediocin against the tested bacterial strains varied from 0.5 to 32 µg/mL. Among them, the lowest MIC was observed against S. aureus, P. aeruginosa, and K. pneumoniae. Similarly, the minimum bactericidal concentration (MBC) values ranged from 2 to 64 µg/mL, with the lowest MBC observed against S. aureus, P. aeruginosa, and K. pneumoniae. The large-scale manufacture of Pediocin, which may be utilized as a natural food preservative to stop the growth of pathogenic bacteria and lower the frequency of foodborne diseases will be made easier by the optimized production circumstances. The potential of Pediocin for food preservation and the security of its use require more research.

Mycobacterium tuberculosis, the causative factor of tuberculosis (TB) infections, has an atypical outer membrane mostly consisting of lipids with long-chain and branched fatty acids termed mycolic acids. These lipids establish a permeability barrier that inhibits numerous environmental solutes from entering the bacteria, making them acid-fast and enabling them to thrive in harsh environments. To meet their target, anti-TB drugs need to penetrate this layer. This review focuses on drug development initiatives that have contributed to TB drug development, lipids’ roles in M. tuberculosis pathogenesis, and recently made fresh remarkable progress in developing novel lead chemical compounds that target their biosynthesis metabolisms. Selective bacterial membrane targeting as a promising therapeutic approach against persistent infectious diseases such as TB has been proposed in this review study.

An opportunistic pathogen Pseudomonas aeruginosa can cause frequent hospital-acquired infections as well as one microorganism in the food spoilage. Also, the emergence of multidrug-resistant P. aeruginosa has become a serious threat to public health.This pathogen has many virulence factors which aid in bacterial invasion as well as toxicity, during infections. Out of different virulence genes in Pseudomonas aeruginosa, oprL (Encoding membrane lipoprotein L) and toxA (encoding exotoxin A i.e. ETA), are predominantly involved in, P. aeruginosa-related infections.

A total of 120 specimens of the bacteria Pseudomonas aeruginosa were collected from Veterinary microbiology and various hospital laboratories. The isolates were initially identified by culturing on MacConkey agar and Eosin Methylene blue (EMB) agar and were further characterized by morphological and biochemical tests. An antibiotic sensitivity test was carried out on 13 antibiotics using the disc diffusion method. Genotypic detection of oprL and toxA genes was performed using a specific PCR test.

The results revealed that the toxA gene was detected by 84.62% in isolates belonging to human samples and 75% in the isolates of animal samples, whereas the oprL gene was detected by 80.77% and only 16.67 % in the isolates were derived from human and animal samples, respectively.

The PCR analysis can help in the fast and specific detection of oprL and toxA genes in P. aeruginosa. Monitoring of these pathogenic genes could prevent the risk of transmission of multi-drug resistant P. aeruginosa, from animals to humans.

Antimicrobial resistance in Klebsiella pneumoniae has been on the increase over the years Therefore, numerous endeavors have been carried out so as to discover another active plant combination as a suitable substitute for antibiotics. This is a Experiment of the activities of antibacteria from the extract from Rumexa alveoli against ebsiella pneumonia.

This study was performed on the standard strain of Klebsiella pneumonia and several clinical strains. The aqueous and ethanol extracts of Rumex alveollatus; formulated by the Soxhlet apparatus. The activities of the antibacterial of the extracts were analyzed with the use of the disk-diffusion method. Furthermore, the minimal-inhibitory-concentration (MIC) and the MBC were examined by the micro dilution method. The database collected by SPSS recent software was evaluated.

Inhibitory zone of ethanol (500 mg/ml) on standard and clinical strains of Klebsiella pneumoniae were 18, 17, 17,15,16, and 16 mm, respectively, and also aqueous extract did not have an antimicrobial effect. MIC and MBC results for ethanol extracts were 125 and 250 mg/ml, respectively.

The antibacterial activities of the Rumex alveollatus ethanol and aqueous extract tested against bacteria was good . Thus, the findingss of this research can be a beneficial report concerning their active role in infection control.

 The emergence of antimicrobial resistance results in morbidities and mortalities associated with many bacterial infections and is a major concerning issue in front of the healthcare system. As a part of a competitive adaptive strategy for its growth, gram-positive bacteria like Bacillus subtilis produce antimicrobial peptides; bacteriocins. These peptides protect other bacterial species.

 To counter antimicrobial resistance, bacteriocins can be considered a potential drug option against drug-resistant microorganisms.

 After isolation and characterisation of B. subtilis from the 5 collected soil samples, the bacteriocin was extracted from these bacteria by using the ‘solvent extraction method’, characterised, and then purified to evaluate its antimicrobial activity against pathogenic bacteria like; Streptococcus pyogenes, Salmonella typhi, Pseudomonas aeruginosa, Klebsiella pneumoniae and Acinetobacter baumannii by using ‘Kirby-Bauer disc diffusion’, method. The bacteriocin stability was also investigated, at different temperatures, pH and incubation times.

 The bacteriocin of B. subtilis showed great antimicrobial activity against S. pyogenes, followed by S. typhi and P. aeruginosa. However, the lowest antimicrobial activity was against A. baumannii. With the increase in the incubation time and temperature, the antimicrobial activity of bacteriocin was decreased, indicating the protein nature of bacteriocin. Compared to the standard antibiotics, the bacteriocin isolated from B. subtilis demonstrated a significant inhibitory effect against the tested pathogens.

 From this study, it can be concluded that bacteriocin can become a potential alternative to standard available medicines. They can be used against antimicrobial-resistant pathogenic bacteria because of their significant inhibitory activity against the tested pathogens compared to the standard antibiotics.

A genetically-identical bacterial population is phenotypically heterogeneous, with phenotypic variants arising due to fluctuations in gene expression. Persister formation may be induced by environmental factors/stress such as antibiotic treatment, signalling molecule indole, quorum sensing molecules, nutrient starvation, oxidative stress, heat stress, hyperosmotic stress, and acid stress. Since persisters are clinically relevant, it is important to study the mechanisms responsible for persister formation so that therapies can be designed to curtail these infections.

A most common opportunistic pathogen, Pseudomonas aeruginosa is present in both humans and animals and responsible for various nosocomial infections and healthcare settings related infections. Different virulence genes like; oprL (membrane lipoprotein L) and toxA (exotoxin A i.e. ETA) in P. aeruginosa, assist in its pathogenicity, toxicity and contribute to high antibiotic resistance. So considering the risk of zoonotic transmission of P. aeruginosa through animal-related foods, this study aimed to monitor the prevalence of oprL and toxA virulence genes and antimicrobial resistance in P. aeruginosa isolates, obtained from animal (Cow’s milk) and human clinical samples.

Of the total 120 collected samples for this study, every 60 samples were collected from animals and humans from respective laboratories. Total 76 isolates of P. aeruginosa were isolated and identified by morphological and biochemical tests. The presence of virulence factors like oprL and toxA were evaluated by PCR analysis and antimicrobial resistance was assessed by antibiotic susceptibility test (Kirby-Bauer method).  

From the total 76, P. aeruginosa isolates obtained from both animal and human isolates, alone presence and coexistence of both toxA and oprL genes in P. aeruginosa isolates; were detected in PCR analysis. PCR analysis results showed in P. aeruginosa isolates, alone distribution of toxA and oprL genes is, 75% and 54.16% in animals, and 84.61% and 80.76% in humans, respectively. The coexistence of both genes was 37.50% and 40.32% in animals and human isolates, along with high antibiotic resistance in most P. aeruginosa isolates.  

Therefore, this study suggested PCR analysis can be used for fast and specific detection of oprL and toxA genes in P. aeruginosa. Monitoring of these genes can help to prevent the risk of transmission of multi-drug resistant P. aeruginosa, from animals to humans.

Pseudomonas aeruginosa (P. aeruginosa) has a wide range of virulence factors. These factors have the potential to increase bacterial pathogenicity and serious infection. The purpose of this study was to evaluate the virulence profiles and antibiotic susceptibility of isolates of P. aeruginosa originated from animal and human samples. The samples were cultured on selective media before being extracted for DNA and subjected to a PCR technique to detect virulence genes. There was a significant difference in the isolation of P. areuginosa isolated from human and animal sources. Where, in humans, the percentage of P. areuginosa was 52 (68.42%) while in animals the percentage of P.aeruginosa was 24 (31.57%). In humans, the percentage of P. aeruginosa in blood was 26.92% (14 isolates), in urine it was 25% (13 isolates), in wound it was 40.38%21 isolates), and in sputum it was 7.69% (4 isolates). We used a PCR technique that produced highly specific and accurate results for detecting virulence factor genes in P. aeruginosa isolates that cause disease in humans and animals. The percentage of exoA genes was (83.33%) and (81.66%) in the animal and human, and that of lasB was (58.33%) and (92.30%) in animal and human samples respectively. Furthermore, both the exoA and lasB genes are found in 26.31% of animal strains and 17.10% of human strains. The disc diffusion method was used to determine antimicrobial susceptibility. In both animal and human isolates, P. aeruginosa showed the highest resistance to amikacin and the lowest resistance to ciprofloxacin. These findings could aid in the understanding of pathogenicity processes, treatment direction, and the development of strategies to control the spread of epidemic P. aeruginosa strains.

 The unprecedented rise in antibiotic-resistant bacterial infections is a challenging dilemma, urging the development of novel and effective antibiotics for the treatment of such infections. Anti-virulence therapy is a promising solution in this regard. Unlike antibiotics, these drugs could lower the selective evolutionary pressure on a bacterial population and target the virulence factor rather than the growth pathways, thereby targeting and repressing the propagation of antibiotic resistance and virulence genes in bacteria. The present study aimed to investigate anti-virulence therapy against bacterial infections, as well as the mechanisms of action and challenges.

This literature review aimed to discuss the issues of antibiotic resistance developed in bacterial infections, the difficulties in antibiotic treatment, the mechanisms involved in anti-virulence therapy, and the approved anti-virulence drug therapeutics.

We outlined the success in overcoming antibiotic resistance by using anti-virulence therapy as an alternate treatment option, while also discussing the drawbacks associated with their use and safety against bacterial infections.

According to the results, anti-virulence therapy combined with antibiotic treatment is effective in the treatment of several bacterial infections.

 Bacillus cereus is one of the important pathogen, which can be found in food samples like milk and principally responsible for food poisoning. Metallo-beta-lactamase (MBL) genes present in the Bacillus cereus bacterium, which provide resistance to the bacteria against the extreme condition. The objective of this study is to carry out molecular detection of blaTEM, blaCTX-M and blaSHV MBL genes in B. cereus strains, isolated from infant dry milk samples.  

 Total 50 samples of infant dry milk were collected from the drug store, and 19 samples were selected for this investigation. After morphological and biochemical characterization of suspected colonies which are obtained from infant dry milk samples, these isolates were confirmed for B. cereus. Antibiotic susceptibility tests were done as per criteria of Clinical and Laboratory Standards Institute (CLSI). The phenotypic confirmatory analysis was done in Mueller Hinton agar (MHA) plates with clavulanic acid. If inhibition diameter is ≥5 mm increases in the clavulanic acid (CA) containing plate than to a plate without CA, it confirmed the presence of MBL genes. PCR used for detection of MBL genes in the isolated strains.

 PCR detected the blaCTX-M (100%), blaSHV (4%) and blaTEM (84.2%) gene of B. cereus in the infant dry milk.

The study confirms that the infant dry milk is a good source of B. cereus, if dry milk has absorbed water content from the air and hence providing a perfect condition for the growth of the bacterium, so It should be kept airtight the dry milk and stored in the cold condition.

Rhamnolipids are hydrophilic glycolipids, often classified as biosurfactants. They are produced by different bacterial species. Rhamnolipids are extensively studied in biological research because of their interesting features like antimicrobial, antifungal, and antiviral activities.

To study the antimicrobial effect of rhamnolipid, we conducted a crosssectional study on the eight different pathogenic bacterial strains from November 2019 to June 2020. These bacterial strains were isolated from the organic compost. Both disk diffusion and broth microdilution methods were used to evaluate the inhibitory effects of rhamnolipids on these pathogenic bacteria. Also, protease and amylase enzyme activities were evaluated in these eight bacterial isolates.

For Bacillus stearothermophilus, within the area of 31.5 mm, no growth was observed, hence proving the inhibitory effect of rhamnolipid. After calculating the minimum inhibitory (MIC) and minimum lethal concentrations (MLC) for each bacterial strain, it has been found that the studied bacteria were more susceptible to rhamnolipids than most of the antibiotics. Strains were also quantified for their enzymatic activity of proteases and amylases. The bacterial strains of Bacillus stearothermophilus, Brevibacillus brevis, Bacillus licheniformis, and Bordetella petrii showed maximum protease activity. Whereas Escherichia coli, Enterococcus faecalis, Enterobacter aerogenes, and Pseudomonas aeruginosa showed high amylase activity.

Rhamnolipids can be used as a potential antimicrobial agent for treatment of infections.

Colibacillosis is one of the most important bacterial diseases of birds that is caused by Escherichia coli. This disease causes considerable economic damage to the poultry industry every year. Various antimicrobial agents are used to reduce the damage caused by this infection. But in recent decades, the increased use of antibiotics has led to the development of resistant genes and, consequently increasing antibiotic resistance of bacteria, leading to a decrease in the efficacy of antibiotics. The purpose of this study was to determine the susceptibility and drug resistance of 178 isolates of 40 chicken flocks in Ardabil province northwest of Iran.

Five carcasses were randomly selected from each flocks with colibacillosis and sampled from liver and heart using sterile swabs. After culture and isolation, colonies were identified by biochemical and serological methods. Antibiotic resistance of all isolates to 19 antibiotics was determined using disk diffusion method based on CLSI guidelines.

Of 200 samples, 178 (89%) were isolated, and 22 (11%) did not grow. In this study the highest antibiotic resistance was observed against flumequine (98.31%), nalidixic acid (97.25%), tylosin (97.20%), oxytetracycline (97.20%), chlortetracycline (95.50%), difloxacin (89.32%), doxycycline (81.47%), enrofloxacin (77.53%), sulfamethoxazole + trimethoprim (71.91%), and the lowest antibiotic resistance was recorded for Linco-Spectin (36.52%), chloramphenicol (22.47%), gentamycin (7.30%), fuzbac (5.05%) and ceftriaxone (3.93%). All isolates were highly sensitive to ceftazidime.

The results of this study showed a high level of resistance to antibiotics commonly used in poultry industry, which is probably due to improper use of antibiotics in poultries.

Lactose indigestion is a common issue since long around the globe. This study involves determination of lactic acid bacteria role during pathogenic infection. The lactic acid bacteria from dairy products are isolated using MRS media to determine their beneficial and harmful effects on growth of pathogenic microorganisms. The lactic acid bacteria include lactose fermenters specifically lactobacillus spp. Eight isolates were tested to determine their antimicrobial activity against pathogens. The zone of inhibition ranges from 11-18mm by lactobacillus spp. (Lactobacillus casei, Lactobacillus salivarious, Lactobacillus brevis, Lactobacillus acidophilus, Lactobacillus bulgaris and Lactobacillus plantarum).This gives the susceptibility pattern against the pathogens(Salmonella typhi, Helicobacter pylori, Staphylococcus aureus, and Pseudomonas aesuginosa).84% of the isolates show the susceptibility pattern against pathogens.The lactic acid bacteria boost the immunity by secreting extracellular antimicrobial products in competitive hostile environment.Thetreatment through antibiotics can be alternated by probiotics intake. This will also avoid pathogenic microorganism to become resistant that is enigma in pharma industries.

Probiotics are “live microbial cells” that are beneficial for human and animal health. Lactobacilli are such a diverse group of bacteria with similar metabolic and physiological characteristics, and constitute important and beneficial gut microflora. During carbohydrate fermentation, lactobacilli produce lactic acid as an end product in metabolism. Hence, lactobacilli have high significance to be used as probiotics in the food industry, because of their acidifying properties. Also, lactobacilli are considered “safe”, owing to their ubiquitous presence in the food. Many researchers provided evidence for the presence of lactobacilli in milk sources. Thus, the present study aimed to isolate and characterize different lactobacilli strains from milk sources and analyze their “probiotic potential”.

Forty-one lactobacilli isolates were obtained from raw cow milk. Then, the strains were characterized by morphological identification and biochemical tests. Besides, probiotic potentials were evaluated with the bile tolerance test, antibiotic susceptibility test, and determining suitable pH for the optimal growth of lactobacilli. The lactobacilli isolates were also analyzed for their probiotic characteristics and the release of antimicrobial substances. Their antimicrobial activities against pathogenic strains were assessed by determining the minimum inhibitory concentration, with the help of agar diffusion methods.

From 50 milk samples, 41 lactobacilli isolates were obtained, out of which five lactobacilli strains were identified as Lactobacillus casei, Lactobacillus plantarum, Lactobacillus brevis, Lactobacillus acidophilus, and Lactobacillus lactis. Moreover, 35 isolates showed an inhibitory effect. These strains were able to survive and grow in 0.5% to 2.5% bile salt concentrations. Lactic acid bacteria were susceptible to antibiotics, and 35 isolates obtained from raw milk showed an inhibitory effect against pathogenic bacteria. The observed minimum inhibitory concentration ranged from 50 to 100 µL and varied between the different pathogens.

Out of 41 Lactobacillus isolates obtained from cow milk samples, 35 were identified with probiotic characteristics. Hence, this study highlighted the novel probiotic bacteria and validated the antimicrobial properties of the Lactobacillus spp against pathogenic bacteria.

 The increasing infections caused by resistant P. aeruginosa strains originate from hospitals. Therefore, many efforts are being made to find new herbal compounds as suitable substitutes for antibiotics.

 The present study aimed to evaluate the antibacterial and anti-quorum activity of Rosmarinus methanol extract on P. aeruginosa.

 This experimental study was performed on standard and clinical strains of P. aeruginosa. The methanolic extract of Rosmarinus was prepared by the Soxhlet method, and the antimicrobial activity of the extract was evaluated by diffusion method in wells and microdilution. We examined the effect of this extract on the antibiofilm activity, protease, and pyocyanin production of P. aeruginosa in order to investigate the anti-quorum sensing activity of methanolic extract of Rosmarinus. Via SPSS 17, we managed to conduct the statistical analysis.

 The mean diameter of growth inhibition zone obtained from methanolic extract of rosemary at a concentration of 500 mg/ml on Pseudomonas aeruginosa was 18.5 mm, and the minimum inhibitory concentration of methanolic extract of rosemary was 125 mg / ml for bacteria. Extract at concentrations higher than 62.5 mg /ml prevented biofilm formation, protease, and the pyocyanin production of P. aeruginosa.

 The results of the present study can be a valuable report on their useful role in infection control because the methanol extracts of Rosmarinus had suitable antibacterial and anti-quorum sensing activity. It is suggested that more studies be conducted on the identification of antimicrobials as a suitable alternative for antibiotics in the treatment of diseases.
 

Background & Aims:

 of the Study: Pseudomonas aeruginosa (P. aeruginosa) is the common cause of nosocomial infections, especially among patients. The aim of the present study was to investigate the occurrence of aminoglycoside resistance and prevalence of the resistance-modifying enzyme genes aac(6')-II and ant(2")-I  in P. aeruginosa isolates from the clinical samples of hospitalized patients in Yazd, Iran.

This cross-sectional study was carried out on P. aeruginosa isolates during March 2016 to March 2017. All clinical samples were initially identified by the standard biochemical method, and their aminoglycoside resistance was studied using the disc diffusion method according to Clinical and Laboratory Standards Institute recommendations. Polymerase chain reaction was conducted for the detection of aminoglycoside resistance using the specific primers of aac(6')-II and ant(2")-I genes.

A total of 144 isolates were evaluated for antibiotic susceptibility testing. The resistance of P. aeruginosa isolates to the tested antibiotics was reported as 118 (81.9%) isolates to kanamycin, 91 (63.2%) isolates to gentamicin, 80 (55.6%) isolates to tobramycin, and 84 (58.3%) isolates to amikacin. The aac(6')-II and ant(2")-I genes were detected in 93 (64.6%) and 114 (79.2%) P. aeruginosa isolates, respectively.

Aminoglycoside resistance in P. aeruginosa remains a significant problem. Therefore, there will be considerable local surveillance of aminoglycoside resistance profile.

Acinetobacter baumannii is a highly virulent bacterium. It causes opportunistic and nosocomial infections and is a threat to healthcare settings. It has also developed multidrug resistance (MDR) capacity. The nosocomial bacteria and antibiotic resistance are primordial and a significant public health concern. These bacteria and their threat can be prevented by reducing infected foodstuffs. Thus, in this study, we investigated A. baumannii isolated from foods in Ardabil City, Iran, and assessed their antibiotic resistance patterns.
The identification of bacterium was made by cell morphological and biochemical tests, including sulfide indole motility medium, Simmons citrate agar, the triple sugar Iron test, urease, catalase and oxidase test. Also, gene BlaOXA-51 was targeted with the polymerase chain reaction test to select potential MDR strains. The disk diffusion method was used to evaluate the antibiotic susceptibility of the isolates. For the detection of antibiotic resistance genes, β-lactamase was conducted with phenotypic and genotypic assays using the combined disk test and PCR.
Among 100 samples, 27 strains of A. baumannii were isolated. Some antibiotics like imipenem showed 100% sensitivity, and ampicillin-sulbactam showed 100% resistance to isolates. Also, a multidrug resistance profile was assessed and the antibiotic-resistance β-lactamase genes were detected. The prevalence of genes encoding extended-spectrum β-lactamase in the isolates were as follows: SHV, 29.62%; TEM, 18.51%; PER, 14.81%.
A. baumannii isolates showed the highest resistance towards ampicillin-sulbactam (100%) and the lowest resistance to imipenem (0%).These results emphasize the importance of detection and implementation of control measures to prevent the spread of A. baumannii in foodstuffs.

Infant milk powder (IMP) is a very suitablemediumfor the growth of micro-organisms such as Bacillus cereus. B. cereus is a spore-producer that can survive easily during the pasteurization process to cause some health problems. This study was carried out to determine the antibiotic resistance pattern of B. cereus isolates producing metallo-- lactamase (MBL) enzymes in IMP samples. After preparing 50 samples of IMP, they were cultured to detect the presence of B. cereus. The Kirby-Bauermethodwas used to determine antibiotic susceptibility and theDDSTmethodto phenotypically detectMBLenzymes. MBLgenes blaVIM, blaSMP-1, and blaIMP were genotypically examined in the isolates by the PCR method. Most samples of IMP had a high level of contamination with B. cereus when compared to national and international standards. The highest percentage of resistance was related to ceftazidime and oxacillin (100%) and the lowest resistance to tetracycline (21.4%) and ciprofloxacin (26.3%). All B. cereus isolates were the producers of MBLin the DDST test. None of the isolates was positive for the blaSPM gene. Of the other MBL genes, the blaVIM gene was seen in all isolates (100%) and the blaIMP gene in 16 isolates (84.21%). Antibiotic resistance is on the rise in the study region due to the production of MBL enzymes. Among MBL-producing isolates, the frequency of the blaVIM gene was more than that of blaIMP and blaSPM-1.

  In a survey of milk samples obtained from individual farms and pasteurized milk plants in Ardabil city, 38% of raw milk samples and 22% of pasteurized milk samples were found to be contaminated with Bacillus cereus. In total 200 milk samples,100 of raw milk and 100 of pasteurized milk, were tested for the presence of B. cereus contamination.     The milk samples tested positive for B. cereus were used to isolate the DNA from the and subsequently used in molecular genetic analysis. Statistically, 38% of raw milk samples and 22 % of pasteurized milk samples were found contaminated with B. cereus. The results of the present study confirms that processed milk also carries a very high probability of B. cereus  contamination .In the present study,  three different primer sets  were used to amplify DNA obtained from B. cereus isolates and the gene expression profile of beta-lactamase producing genes (SHV,TEM,CTX-M) were analyzed using PCR.    TEM types of beta-lactamases exhibited maximum percentage frequency in raw milk isolates whereas pasteurized milk isolates had the most frequency of CTX-M type of beta-lactamases. It was observed that both raw and pasteurized milk are a source of B. cereus as evident by pure isolates obtained on agar plates.

   The gene expression profile shows that milk samples are frequently contaminated with antibiotic resistant strains of B. cereus.

The present study was carried out to detect Salmonella enterica in meat samples of commercial boilers (CB) and the spent hens (SH) in Ardabil, Iran. Metallo-β-lactamase (MBL) enzyme produced by Salmonella enterica strains isolated from poultry meat samples were detected by both biochemical and molecular methods. The study included 20 positive samples for Salmonella  enterica from boilers (CB) and spent hens (SH). The prevalence of Salmonella enterica for CB was 22% (11/50) and for SH was 18% (9/50). The antibiotic susceptibility testing for both CB and SH showed maximum number of Salmonella enterica isolates were resistant against Augmentin (30 μg), Cotrimaxazole (25 μg) and Tetracycline (25 μg) and susceptible against Ofloxacin (5 μg) and Gentamicin (10 μg). Screening phenotypic confirmatory test for Metallo-β-lactamase (MBL) for CB, (n= 11, 100%) were positive for MBL while for SH (n= 8, 88.88%) samples were positive for MBL. The results showed that MBL positive Salmonella enterica isolates from CB and SH meat samples contained gene blaVIM (n=11, 57.89%), blaIMP (n=6, 31.57%) and blaSPM-1(n=2, 10.52%). Since Salmonella infections in poultry are high due to large demand and antibiotic resistance to strains, so the purpose of the current study is to focus on the detection of MBL enzyme produced by Salmonella enterica isolates.