جستجوی مقالات مرتبط با کلیدواژه « مقاومت آنتی بیوتیکی » در نشریات گروه « صنایع غذایی »

Vibrio cholerae is one of the important human pathogens that is transmitted through contaminated water and food. In Qom province, due to special weather conditions, diseases caused by Vibrio cholerae are endemic. The aim of this study was the prevalence of Vibrio cholerae in water and vegetables of Qom province and the presence of two virulence genes, hlyA and toxR. During two years (2020-2021), 120 samples of agricultural water (70) and vegetables (50) in Qom province were collected. The samples were cultured on specific media. Suspicious colonies were evaluated by Gram staining and biochemical tests and the serotype Vibrio cholerae was identified by serology test. Finally, Then, the presence of virulence genes was investigated by PCR method and also the antibiotic resistance pattern by disk diffusion method was evaluated in the isolates.  Vibrio cholera bacteria were isolated from 17 samples (16.14%), all of which were Non-O1. The rate of contamination of water and vegetables was 28.14% (10 cases) and 14.00% (7 cases), respectively. In molecular evaluation, the abundance of virulence genes including: toxR (88.32%), rtxA (58.82%), hlyA (47.05%), chxA (5.88%), and 100% of isolates did not have ctxA, ace and tcpA genes. The most antibiotic resistance is related to ampicillin and amoxicillin (34.29%), followed by cefuroxime (17.46%), imipenem (11.76%), and cefoxitin and trimethoprim-sulfamethoxazole (5.88%). The results of this study showed that Vibrio cholerae Non-O1 is present in water and vegetables of Qom province, and as an important source of disease for humans therefore, continuous health monitoring of water and vegetables and proper disinfection of these foods is very important.

Vibrio parahmolyticus is a marine and estuarine bacterium that damages the aquatic industry due to food-related outbreaks and is a great threat to food safety and human health. Annually, many reports of food poisoning occur due to consumption. Seafood contaminated with Vibrio bacteria is released. The present study was conducted in order to investigate the frequency of Vibrio parahaemolyticus isolated from Caspian sea fish and to determine the pattern of antibacterial resistance.For five months (June 2021 to October 2021), 220 samples of fish caught from the Caspian Sea were prepared from the Gilan Fisheries Department with full compliance with health conditions. To isolate Vibrio parahemolyticus, after enrichment in buffered peptone water for 24 hours at 37°C, a loop was cultured in thiosulfate citrate bile sucrose agar medium for 24 hours at 37°C. The day after the colony yellow and green suspects are used from standard differential tests. In addition, to determine the pattern of antibiotic resistance according to CLSI guidelines, antibiotic disks of MAST Company were used. Out of a total of 220 fish samples caught from the Caspian Sea, 759% of the fish samples were infected with Vibrio species. Vibrio parahaemolyticus abundance was reported as 19%, which was more than the other species obtained.Also, the results obtained from the antibiotic resistance pattern indicate the sensitivity of this strain to ciprofloxacin antibiotics (98.9%, gentamycin (87.8%), chloramphenicol (92.4%) and their resistance to amoxicillin (96.3%), doxycyclin (94.1%) and tetracycline (92.3%). Our findings showed that the fish studied in the Caspian Sea are infected with Vibrio parahaemolyticus, which can be considered a serious threat to the health of seafood consumers.

In this study, the bacteria of the food cold storages of three big hospitals in Tehran were evaluated. Sampling of food refrigerators from different departments of 3 hospitals with more than 400 beds was done once a week during 10 consecutive months from June to March 2018. After determining the identity of the isolates with differential tests, the pattern of antibiotic resistance was determined and the presence of antibiotic resistance genes of resistant strains was checked by molecular PCR method. A total of 236 positive samples were isolated from refrigerators and 42 positive samples from cold rooms of three hospitals. The most positive samples were obtained from devices with inappropriate appearance, temperature above 8°C, and the floors of refrigerators. Most of the isolates belonged to the bacterial group Enterobacter (68.8%), Staph (11.9%) and Enterococcus (10.6%). 2 cases of salmonella spp and 1 case of L. monocytogenous were isolated from cold storages. Refrigerated samples were sensitive to all antibiotics used in this study. In refrigerator isolates, the highest resistance was related to ESBL (9.7%), VRE (5.3%), MRSE (0.4%) and MRSA (0.4%), respectively. In the extensive investigation of resistance genes, blaOXA-48, blaCTX and blaTEM genes were found in 10% of Enterobacter group isolates. blaOXA-51 gene was found in all non-Enterobacter resistant strains and mecA and vanA genes were found in staph and enterococcus resistant isolates. Bacterial contamination of hospital refrigerators is a warning about the possibility of transmission of contamination, outbreak of disease, failure in treatment, exacerbation of disease complications and risk of transfer of resistant genes from resistant strains to sensitive strains.

Nowadays, the occurrence of antibiotic-resistant bacterial strains in food is increasing, which makes antibiotic treatment of infected food more difficult. One of the food sources that can cause foodborne infection is dairy products made from raw milk and one of the bacteria resistant to various antibiotics is Salmonella. The aim of this study was to investigate the presence of antibiotic-resistant Salmonella species in Poosti and Koozeh cheeses produced from raw milk in western Iran. For this purpose, the probable Salmonella species were isolated in Koozeh cheese from Bukan and Poosti cheese from Lorestan and Kermanshah. After initial phenotypic identification and biochemical testing, molecular identification was performed by amplification of the 16S rRNA gene with primers U1492R and B27F. The isolates were tested for resistance to tetracycline, oxacillin, penicillin and ampicillin. The results confirmed the presence of Salmonella enterica subspecies Typhimurium in all three cheeses among 14 Enterococcus isolates. The species of all three cheese were resistant to oxacillin, penicillin and ampicillin and the identified species of Lorestan Poosti cheese were resistant to tetracycline. But the identified species in Kermanshah Poosti cheese and Bukan Koozeh cheese were sensitive to tetracycline. The results of this study indicate that local Poosti and Koozeh cheeses in some western parts of the country may be carriers of antibiotic-resistant Salmonella strains and that in case of microbial infection caused by contaminated cheese, treatment with antibiotics may be difficult.

Brucellosis is a momentous zoonotic disease. Unpasteurized milk and milk products are the leading sources of Brucella transmission to humans. The present research was conducted to investigate the contamination of local crumbled Kope cheeses distributed in Urmia city with Brucella species and evaluate the antibiotic-resistance pattern of the isolates. Fifty samples of local cow’s Kope cheese were randomly collected from traditional dairy retailers in different regions of Urmia by sterile conditions in 2022. The samples were cultured in Brucella enrichment broth and then in Brucella selective agar with a supplement. Molecular identification of Brucella spp. was done using specific primers by polymerase chain reaction (PCR). Antimicrobial susceptibility testing on the isolates was performed by the Kirby-Bauer disc diffusion method. Among the tested samples, two samples were contaminated with Brucella (4%). One was contaminated with B. abortus bv. 1, 2, and 4 (2%), and the other with B. melitensis (2%). The isolates were sensitive to azithromycin, imipenem, doxycycline, rifampin, and co-trimoxazole antibiotics and were resistant to ampicillin, amoxicillin-clavulanic acid, tetracycline, gentamicin, and ceftriaxone antibiotics. Also, the B. abortus strain was sensitive to ciprofloxacin, but the B. melitensis strain was resistant. The isolates showed multi-drug resistance (MDR) characteristics. From the findings, it can be concluded that Brucella contamination in local Kope cheeses distributed in Urmia city is low; However, due to the high pathogenicity of B. melitensis for humans, it is recommended to screen infected cows, vaccinate sheep and goat herds, and prevent the supply of unpasteurized milk and milk products. It is also recommended to evaluate azithromycin and imipenem antibiotics along with other common antibiotics in brucellosis.

The presence of methicillin-resistant (MRSA) and vancomycin-resistant (VRSA) Staphylococcus aureus in food raises a public health concern. This study aimed to investigate the antibacterial and anti-biofilm activity of some Lamiaceae essential oils including Melissa Officinalis, Salvia officinalis, and Mentha piperita against MRSA and for the first time on VRSA strains. For this purpose, the disk diffusion test, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), minimum biofilm inhibitory concentration (MBIC), and minimum biofilm eradication concentration (MBEC) were determined. Then, M. Officinalis essential oil compounds were investigated against PBP2a, agrA, and Bap proteins using AutoDocK Vina. Finally, pharmacokinetic properties were investigated using ADMETsar and SwissADME servers. Based on the obtained results, the MIC and MBC values of M. Officinalis essential oil against MRSA strain were equal to 0.05 and 0.112 mg/ml, and against VRSA strain were equal to 1.8 and 2.5 mg/ml, respectively. The MBIC and MBEC of M. Officinalis essential oil against MRSA strain were equal to 0.03 mg/ml and 0.112 mg/ml, and against VRSA strain were equal to 0.9 mg/ml and 3.2 mg/ml, respectively. The results of molecular docking showed that β-Caryophyllene had a greater binding affinity to PBP2a protein either in the active site or in the allosteric site (-6.6kcal/mol). On the other hand, the effective compounds of this essential oil, especially citronellol, thymol, and citral, were acceptable in terms of pharmacokinetic properties. Since natural antibiotics can be an alternative to conventional antibiotics in the treatment of Staphylococcus aureus food-borne diseases, the results of this study showed that Melissa Officinalis essential oil is effective on the growth and biofilm of MRSA and VRSA strains, and it can be used as a drug candidate in the prevention and treatment of infections caused by antibiotic-resistant strains of this bacterium.

Macrolide antibiotics are important for the treatment of Campylobacter jejuni infections. Resistance to this class of antibiotics in Campylobacter is a complex process with dynamic molecular changes that are not well defined. In the present study, to fill the gap related to antibiotic resistance to Erythromycin treatment, the transcriptomic response of Campylobacter jejuni strain NCTC11168 to Erythromycin (ERY) treatment was determined by microarray method. The obtained data were identified, extracted and analyzed with GEO2R online tools and R software. Genes with the highest differential expression were identified by using parameters P<0.05 and LogFC |>1|. Then, the expression of the related genes was separated and for the genes that had an increase in expression, the protein network was predicted through the STRING database and visualized with the Cytoscape software. By identifying different genes that had a significant decrease or increase in expression, it was found that a set of flaA, flaB, flgB, CmeC, sdhA, sdhB genes can play a role in the antibiotic resistance of Campylobacter jejuni to the treatment with Erythromycin antibiotic. In this study by examining the goals, effectiveness and functional analysis of these genes, suitable solutions to curb the resistance were presented.

Escherichia coli  induced urinary tract infection urinary tract infections is a prevalent acquired infection in Iran. The IutA virulence gene plays a crucial role in the pathogenesis of E. coli, particularly in binding to epithelial cells.  In addition, as a group of probiotics, lactobacilli have an important role in the body and are therapeutically benefits in some cases. This study aimes to molecularly investigate the effect of Lactobacillus casei PTCC 1608 on different strains of uropathogenic E. coli  isolated from urinary infection through PCR. The desired strain of E. coli was isolated from patients with urinary tract infections and investigated through differentiation methods. The IutA gene of the desired strain was evaluated through PCR and then strains with positive genotypes were isolated and the antibacterial effect of Lactobacillus casei was evaluated through dilution and disc diffusion methods in a liquid medium. The antibacterial effect of Lactobacillus casei on antibiotic-resistant uropathogenic E. coli was studies. From a total of 40 samples isolated from the urine of patients with urinary tract infections, the results of MIC-MBC were either positive or negative. The antibiotic sensitivity test at the dilution of 1 to 10 showed an inhibition zone of 9 cm. These results indicated that the isolated bacterium was not resistant to ampicillin and the antibiotic did not lose its therapeutic effect. Moreover, the probiotic used has a therapeutic role and can improve urinary infections.

The presence of antibiotic-resistant genes in local cheeses is not desirable due to the risk of gene migration, increased resistance to antibiotics in consumers, and therefore the effectiveness of related drugs during the treatment period. Recently, the studies showed that the demand of local cheeses made from raw milk have increased. However, there is concern that consumption of these cheeses could increase the risk of antibiotic-resistant genes transfer through bacteria especially Enterococcus spp to consumers. Of course, traditional fermented products may contain intrinsic microbial flora with unique useful properties, including the production of antimicrobial metabolites and resistance to phages, which is very important for the dairy industry. The ability of bacteriocin production by the microbial flora that responsible for fermentation of cheeses made from raw milk is very important because it prevents the growth of pathogenic bacteria. Therefore, the aims of this study were the evaluation of the presence of antibiotic-resistant microbial flora of local cheeses made from raw milk and the investigation of the useful properties such as the presence of its antimicrobial metabolites.

Cheese made from raw milk was produced based on a traditional recipe. For isolation of Enterococcus spp., KAA agar was used, followed by incubation for 48 h at 37°C. The serial dilution of cheese was carried out until the final dilution of 10-8 in ringer. For isolation of Enterococcus spp., a 100 µl of diluted sample was cultured on KAA agar, then incubated for 48 h under anaerobic conditions at 37°C. The catalase-negative and Gram-positive isolates were phenotypically distinguished at genus level using physiological tests )growth at salt concentrations 6.5% and 18%, pH 9.6 and 4.4, temperatures 10°C and 45°C and gas production. After phenotypic detection of isolates at genus level, culture-dependent characterization through PCR and subsequently sequencing was carried out. DNA extracted from cheese was proliferated and sequenced by NGS technique. The metagenomics data were processed for phage resistance, antibiotic resistance, bacteriocin and antioxidant components production. Furthermore, antibiotic resistance of isolates and antimicrobial properties of cell free supernatant (CFS) from cheese were evaluated.

A total of 20 bacteria were isolated from cheese and molecularly identified as Enterococcus malodoratous (60%), Enterococcus faecalis (5%), Enterococcus duran (5%), Enterococcus spp. (30%). Also, the metagenomic analysis showed that Enterococcal community of cheese include Enterococcus malodoratous (72%), Enterococcus faecalis (6%), Enterococcus italicus (13%), Enterococcus spp. (10%) and its microbiome is resistance to ‌-antibiotics ‌and bacteriophages and has the production potential of antioxidant compounds and antimicrobial compounds such as plantaricin. Moreover, laboratory tests confirmed ‌‌antibiotics resistance and antimicrobial properties of isolates.

This study showed that some local cheeses can be responsible for transferring antibiotic-resistant genes to humans and consumption of these cheeses should be limited.

Escherichia coli  induced urinary tract infection urinary tract infections is a prevalent acquired infection in Iran. The papG virulence gene plays a crucial role in the pathogenesis of E. coli, particularly in binding to epithelial cells.  In addition, as a group of probiotics, lactobacilli have an important role in the body and are therapeutically benefits in some cases. This study aimes to molecularly investigate the effect of Lactobacillus casei PTCC 1608 on different strains of uropathogenic E. coli  isolated from urinary infection through PCR. The desired strain of E. coli was isolated from patients with urinary tract infections and investigated through differentiation methods. The papG gene of the desired strain was evaluated through PCR and then strains with positive genotypes were isolated and the antibacterial effect of Lactobacillus casei was evaluated through dilution and disc diffusion methods in a liquid medium. The antibacterial effect of Lactobacillus casei on antibiotic-resistant uropathogenic E. coli was studies. From a total of 40 samples isolated from the urine of patients with urinary tract infections, the results of MIC-MBC were either positive or negative. The antibiotic sensitivity test at the dilution of 1 to 10 showed an inhibition zone of 9 cm. These results indicated that the isolated bacterium was not resistant to ampicillin and the antibiotic did not lose its therapeutic effect. Moreover, the probiotic used has a therapeutic role and can improve urinary infections.

Eugenia caryophyllata (Clove) has long been used as a medicinal plant to treat infections and prevent food spoilage. In this study, with three methods of hydro distillation, steam distillation and hydro-steam distillation, clove buds were extracted and the yields of these methods were 10.9, 9.9 and 8.3%, respectively, which had the highest efficiency for water extraction method. Essential oils obtained by different methods were analyzed by GC-MS and 17 essential oil components were identified. Among these components, acetic acid, eugenol, eugenol acetate, m-eugenol, caryophyllene, hexadecanoic acid were the predominant components, the amount of which in all three types of essential oils were significantly different from each other. Also, the antibacterial effect of essential oils along with 12 common antibiotics on three types of Gram-positive bacteria (Staphylococcus aureus, Streptococcus mutans, Staphylococcus epidermidis) and Gram-negative (Escherichia coli, Salmonella typhimurium, Pseudomonas aeruginosa) were studied and compared. The results showed that the essential oil extracted with hydro-steam, compared to other extraction methods, has a significant antibacterial effect so that its effect on Staphylococcus aureus from Erythromycin, penicillin, glucosacin, vancomycin, tetracycline, ciprofloxacin, ceftriaxone, ceftriaxone Amikacin and gentamicin were stronger, and the effect was similar to that of ampicillin, tobramycin. In conclusion, obtained results showed that clove essential oil can be used as antimicrobial compenent for different appliactions as well as for food applications.

Carum copticum Essential oil (CCEO) after drying in the shade, to hydro-distillation by a Clevenger apparatus was extracted. The antimicrobial activity of CCEO were evaluated dilution preparation by disc diffusion method and well diffusion agar. In order to standardize the method of standard microorganism (ATCC) were used. The results showed that the inhibition zone diameter increased in the two methods of diffusion disk agar and well diffusion agar by increasing the essential oil concentration. The smallest inhibition zone diameter against different CCEO concentrations belonged to Gram-negative bacteria (Pseudomonas aeruginosa). The results of WAD and DDA demonstrated that Gram-positive bacteria were more sensitive to TPEO than the Gram-negative ones. The most inhibition zone diameter against different CCEO concentrations belonged to Gram-positive bacteria (Staphylococcus aureus). The minimum inhibitory concentration (MIC) of CCEO for Staphylococcus aureus, Streptococcus pyogenes, Bacillus subtilis, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans was 0.5, 1, 2, 2, 4, 8 and 1 mg/ml respectively. The minimum bactericidal/fungicidal concentration (MBC/MFC) for microorganisms was 1, 2, 2, 4, 4, 8 and 1 mg/ml respectively.

Dual properties of Enterococcus on the one hand, have made them suitable and accepted bacteria as starter cultures in the production of food products and probiotics, but on the other hand, because of antibiotic resistance properties and virulence factors, has resulted in concerns about the consumer’s health. In this study, in order to evaluate the antibiotic resistance of enterococcal isolates, the disk diffusion method was used. Also, culture-based method was applied for hemolytic and gelatinase activities. The results of the inhibition zone of Enterococcus isolates against common clinical antibiotics revealed that the isolates were sensitive to Vancomycin and Ampicillin and are resistant to Kanamycin and Streptomycin. The isolates showed very little resistance to Tetracycline and Chloramphenicol and none of the isolates were resistant to all tested antibiotics. Results obtained from hemolytic activity of isolates showed that none of examined isolates were capable of blood hemolysis and consequently no clear zone of inhibition in medium containing sheep’s blood. All of isolated were γ hemolytic and they have no hemolytic activity. Gelatinase activity results confirmed that none of the isolates are able to produce clear zone in tryptone soy agar containing gelatin.