مقاومت آنتی بیوتیکی

Vancomycin resistance in intensive care units has significant complications and additional costs. Given the need for rational use of this antibiotic to prevent the occurrence of antibiotic resistance, the present study was designed to evaluate how to prescribe the antibiotic vancomycin consumption pattern in a pediatric subspecialty hospital.

This cross-sectional descriptive-analytical study was conducted over a 3-month period (February, May, and June) in 2021 at the Pediatric Hospital of Jundishapur University of Medical Sciences, Ahvaz. All patients hospitalized in the intensive care unit and infectious disease ward with vancomycin prescription were included in the study. Patients who were hospitalized for less than three days or had no desire to enter the study were excluded from the study. Vancomycin prescription by clinical pharmacist was reviewed based on the latest version of Lexicomp from Wolters Kluwer and the National Health Service (NHS) guidelines.

Of the 91 hospitalized patients, 70.3% (64 cases) were prescribed vancomycin without performing an antibiogram culture based on experience and 29.7% (27 cases) were based on an antibiogram culture. In 96.7% (88 cases) , the duration of intravenous vancomycin infusion did not comply with the protocol. Red Man Syndrome was observed in 8.8% (8 cases). In 91.2 % (83 cases), no adverse effects were reported. In 65.9% (60 cases), the drug dose was determined based on the correct renal function Glomerular filtration rate (GFR) and in 34.1%, the drug dose was determined regardless of the renal function of the patients. Vancomycin doses were lower and higher than the guidelines in 6 and 25 patients, respectively. Out of all patients, eighty four cases recovered and seven cases died.

In almost half of the patients, Vancomycin were prescribed based on experience and without performing an antibiogram test. Use of guidelines, Serum level monitoring programs and continuous medical education for doctors can be effective in rational use of antibiotics.

The indiscriminate use of antibiotics causes the increasing trend of microbial resistance, followed by the limitation of treatment options, complicated treatment processes, and heightened expenses within the healthcare system. In this study،, it was investigated the antibiotic resistance of Escherichia coli obtained from urine culture samples in the central laboratory of Meybod City.

This descriptive cross-sectional study was conducted on urine cultures submitted by the patients referred to the central laboratory of Meibod City in 2022. Antibiotic resistance in 300 E. coli cultures was investigated, and the data were analyzed using SPSS 16 software and a Chi-square statistical test based on age،, gender, and antibiotic resistance.

The greatest antibiotic resistance of E. coli was observed at ampicillin at 83.8%, cotrimoxazole at 65.1% and cefazolin at 68.4% followed by cefotaxime 63.3% and ceftriaxone 61.3%, while the lowest resistance was noted for imipenem at 3% and amikacin nitrofurantoin at 3.3%. Resistance to cefazolin, ceftazidime، gentamicin، cefepime، ciprofloxacin, and amikacin was significantly higher in men compared to women. The greatest resistance to ampicillin, ceftazidime, cefotaxime, ceftriaxone, cotrimoxazole antibiotics was notebly observed in the age group of 60- 41 years, while the least resistance was found in the age group of 21-40 years. Women showed significantly the  the highest resistance to cefepime in the surgical department and the lowest in the emergency department, resistance to levofloxacin was the highest in the internal ward and lowest in the infectious ward, and resistance to Nitrofurantoin in the cardiac department compared to other departments.

The current study shows high antibiotic resistance to E. coli isolates in patients with urinary tract infections referred to the laboratory، especially in the population of men and elderly people. In order to prevent the spread of treatment resistance، urine culture should be done in patients.

Escherichia coli is responsible for 80-90% of urinary infections in outpatients and 30-50% of urinary infections in inpatients. The selection of inappropriate antibiotics for treatment has led to an increase in antibiotic resistance in E. coli isolates over the past few decades. The aim of this study was the phonotypical and molecular investigation of E. coli strains isolated from urinary tract infections and study the pattern of antibiotic resistance. We also evaluated the frequency of antibiotic resistance genes of qnrA in relation to quinolone resistance genes.

In this cross-sectional study, 100 E. coli strains isolated from urinary tract infections of patients admitted to Sina Hospital in Hamadan City were collected and studied by phenotypically and molecular methods. An antibiotic resistance pattern was determined using the disk diffusion method, and specific primers for the qnrA antibiotic resistance gene were evaluated using the polymerase chain reaction method.

Finally, among 100 confirmed E. coli isolates, 70% of the strains were resistant to nalidixic acid, 53% to levofloxacin, and 59% to ciprofloxacin. The frequency of the qnrA resistance gene was 28%.

The present study showed the high resistance of E. coli to quinolones. The presence of the qnrA gene can be one of the factors contributing to this resistance

One of the significant challenges in treating urinary tract infection (UTL) is emergence of antibiotic resistance bacteria. Gepotidacin, a new antibiotic, has been designed to combat bacterial infection, practically UTIs, and may serve as a traditional antibiotic. The present review study aims to investigate the efficacy and safely of Gepotidacin in treating UTIs, practically those caused by antibiotic resistant bacteria.

A comprehensive search of PubMed and Google Scholar databases was conducted to identify relevant studies published between 2010 - 2024. The search keywords included urinary tract infection, Gepotidacin and antibiotic resistance.

Gepotidacin has demonstrated potent antibacterial activity against range of pathogens, including Gram-positive and Gram-negative bacteria, practically those resistant to Fluoroquinolones and other antibiotics. Minimums inhibitory concentrations (MIC) of Gepotidacin was found to be lower than that of other antibiotics, including its potential as a more effective treatment option.

Gepotidacin is a promising antibiotic that may provide a solution to growing problems on antibiotic resistance in UTIs. Its unique mechanisms of action, which targets the DNA gyrase and topoisomerase IV enzymes, makes it an attractive alternative to traditional antibiotics.  Further studies are needed to fully explore the potential of Gepotidacin in clinical practice.

Acinetobacter baumannii is one of the most common causes of hospital infections, and infections caused by this organism cause high mortality in children. The emergence of resistance to last-line antibiotics in A. baumannii is worrying. The aim of this study was to determine the pattern of antibiotic resistance and investigate the mutations in the trm gene, as a resistance mechanism, in tigecycline- resistant isolates obtained from children.

In this cross- sectional- descriptive study, A. baumannii isolates were collected from Children's Medical Center in Tehran, Iran during a one- year period. Definitive identification of the isolates was done by identifying blaOXA-51-like and rpoB genes by polymerase chain reaction (PCR). Then, antimicrobial susceptibility testing of the isolates was assessed using Kirby- Bauer disc diffusion method. Minimum inhibitory concentration (MIC) of colistin and tigecycline were determined by broth microdilution test and E-test, respectively. The presence of trm gene was measured by PCR. Investigation of possible mutations in trm gene was specified by DNA sequencing in tigecycline- resistant isolates.

In this study, 67 clinical isolates of A. baumannii were collected. All isolates were sensitive to colistin. Three isolates (4.4%) were resistant to tigecycline with MIC= 8 mg/l and 13 isolates were moderately sensitive to tigecycline. DNA sequencing results of 3 tigecycline resistant isolates showed mutation in trm gene in all three isolates.

Since tigecycline is a drug of last resort antimicrobials for the treatment of MDR A. baumannii isolates, this growing rate of resistance will make treatment difficult. This emphasizes the necessity of further investigation of resistance mechanisms in order to prevent the emergence of more resistance. The results obtained from this study indicate the important role of mutation in the trm gene in the resistance of A. baumannii to tigecycline.

Incorrect and excessive use of antibiotics has led to a significant rise in drug resistance. Nowadays, irrational antibiotic use is a major contributor to increased illness, death, and healthcare costs. Therefore, the present study aimed to investigate the pattern of Teicoplanin use in hospitalized patients at teaching hospitals in Birjand, Iran, from 2022 to 2023.

This descriptive cross-sectional study based on hospital data was conducted on all patients hospitalized in the wards of Vali-Asr, Imam Reza, and Razi teaching hospitals in 2022 and 2023 who were prescribed Teicoplanin. In this study, all the information required by the patients was recorded in Excel based on the study objectives, as well as the global protocols of the Infectious Diseases Society of America (IDSA(, and American Society of Health-System Pharmacists )ASHP(. Finally, the results were analyzed using the SPSS (version 26) software.

The study included 73 patients with a mean age of 64.26±17.90 years; 37 (51%) were women. The most common clinical conditions leading to Teicoplanin administration were pneumonia (73%) and sepsis (32.9%). According to the results, 87.7% of Teicoplanin treatments were based on antibiogram test results, while only nine patients (12.3%) received empirical Teicoplanin treatment. In 11% of cases, the loading dose of Teicoplanin was correctly administered. Additionally, the maintenance dose was correctly administered in 54 patients (74%). In addition, adverse drug reactions to Teicoplanin were observed in 12 patients (16.4%). The results revealed that 67 patients (91.8%) were admitted to the Intensive Care Unit (ICU). According to the researcher-developed checklist, only four patients (5.4%) adhered to all protocol guidelines.

According to the findings, the patterns of rational Teicoplanin prescription in the studied hospitals do not sufficiently align with existing guidelines and standards.

"Klebsiella pneumonia" is an opportunistic human pathogen known for its ability to form biofilms, which contribute to multidrug resistance. This study investigates the green synthesis of silver nanoparticles and their effects on the expression of biofilm-related genes in "Klebsiella pneumonia" strains.

In this cross-sectional descriptive study, 60 urine samples were collected and subjected to biochemical verification tests. Ethanolic extract of garlic ("Allium sativum") was prepared for the green synthesis of silver nanoparticles. Characterization of the synthesized nanoparticles was performed, and "Klebsiella pneumonia" biofilm formation was assessed by measuring color intensity associated with biofilm presence. The resistance pattern of the bacteria was determined using the disk diffusion method, and the minimum inhibitory concentration (MIC) of silver nanoparticles against biofilm-forming strains was evaluated using the microdilution method. Multiplex PCR was conducted to identify the genes "mrkD", "sugE", and "luxS", and the expression levels of these genes were analyzed using Real-Time PCR.

Among the 60 samples, 36 were confirmed as "Klebsiella pneumonia", and all strains tested positive for biofilm formation. Most isolates were classified as multidrug resistant (MDR). The synthesized silver nanoparticles exhibited a spherical shape, black color, and an average size of 60 nm. They demonstrated antibacterial activity against all isolates, with MIC values ranging from 6.25 to 100 μg/ml. The highest frequency of the "luxS" gene was found in 30 isolates (83.33%), while "sugE" and "mrkD" were present in 23 isolates each (63.88%). Notably, the expression of "mrkD", "sugE", and "luxS" genes significantly decreased in cells treated with silver nanoparticles compared to the control group.

The study concludes that silver nanoparticles effectively inhibit biofilm formation and antibiotic resistance in "Klebsiella pneumonia" isolates, suggesting their potential utility in managing multidrug-resistant infections in hospitalized patients.

 Milk and its products are a suitable environment for the growth of pathogenic microorganisms, among the cold-loving pathogens Yersinia enterocolitica is one of the bacteria whose spread can threaten the health of consumers. The aim of the present study was to Prevalence of antibiotic-resistant strains of Yersinia enterocolitica isolated from traditional and industrial dairy products sold in Isfahan county.

 First, 300 samples of traditional and industrial dairy products were sampled and transferred to the laboratory, and the level of contamination with Y. enterocolitica was determined by standard methods. Multiplex PCR method was used to determine the frequency of virulence genes and Disk-Diffusion method was used to evaluate antibiotic resistance.

 The results showed that the level of contamination with Yersinia enterocolitica was 15 samples (7.5%) out of a total of 200 traditional dairy samples, and none of the industrial samples were contaminated with Yersinia enterocolitica. According to the PCR test, the frequency of the highest and lowest carrier genes, respectively, includes ail 14 samples (4.66 %), yadA 7 samples (2.33 %), inv 10 samples (3.33 %), yst 9 samples (3 %), rfbe 9 samples (3%) and virF 6 samples (2%). The results of antibiotic resistance showed that the highest resistance was related to penicillin (80%) and ampicillin (73.33%), and the lowest resistance was to imipenem (6.66%).

 The results of this study showed that traditional dairy products were contaminated with Yersinia enterocolitica bacteria and had virulence genes, so the use of traditional dairy products should be limited and the use of antibiotics should be limited in the event of illness.

Listeria monocytogenes has been the subject of numerous studies due to its tolerance in cold temperatures, microaerophilic and mobile nature, high salt tolerance, and causing abortion in pregnant women. Due to the presence of the virulence gene in the heat-dependent chromosome, it becomes more severe when growing in the refrigerator. It has received assiduous attention and research due to its resistance to the low limit of pasteurization temperature (7200C), listeriolysin O production, intracellular invasion power and resistance in phagocytosis, the ability to carry out hemolysin β, and wide distribution in food. The prevalence of monocytogenes contamination in raw milk in Amol is 35%, and in local butter, it is 10%. In Isfahan, the prevalence rates of monocytogenes contamination are 19.7% in raw milk and traditional products, 19.4% in ice cream, 11.0% in cream, and 4% in porridge. In Marvdasht, it is 13.8% in cheese. In Qazvin, the prevalence rates are 10.9% and 7% in traditional and white cheeses, respectively. In Marvdasht, the highest antibiotic resistance of raw milk was against tetracycline and ceftriaxone. In Amol, the highest antibiotic resistance of raw milk was against ampicillin (87.7%) and tetracycline (71.4%), and the highest antibiotic resistance of local butter was to erythromycin (100% resistant) and ampicillin (100% semi-resistant). The prevalence of Listeria monocytogenes in Tehran, Isfahan, Chaharmahal-Bakhtiari, and Fars (Shiraz) provinces has been reported between 1.1 and 40% in different years. Therefore, this study was conducted taking into account the increasing prevalence of monocytogenes in foods of animal origin and the substantial risk of an epidemic disease.

Group B Streptococcus (GBS), or Streptococcus agalactiae, is a major cause of invasive diseases such as meningitis and septicemia in newborns, as well as various diseases in pregnant women and non-pregnant adults with underlying conditions. This bacterium colonizes the vagina and rectum in 10% to 30% of pregnant women. GBS colonization in pregnant women increases the risk of preterm delivery and transmission of the bacteria to the baby during childbirth. Penicillin is the first-line antibiotic for treating GBS infections, while macrolides (e.g., erythromycin), lincosamides (e.g., clindamycin), and streptogramins have been recommended as alternative treatments. However, the prevalence of antibiotic resistance is rising and could lead to significant clinical challenges. Therefore, this study aimed to investigate the prevalence of resistance to erythromycin and clindamycin, as well as the associated resistance genes, in GBS strains isolated from pregnant women in Iran.

This meta-analysis examines studies focused on resistance to erythromycin and clindamycin in GBS strains isolated from pregnant women. A comprehensive search was conducted across databases, including PubMed, Scopus, Web of Science, SID (Scientific Information Database), and Google Scholar, using keywords such as Streptococcus agalactiae, Group B Streptococcus, antibiotic resistance, erythromycin, clindamycin, MLSB (macrolide, lincosamide, and streptogramin B) resistance, and related terms. Inclusion criteria included sufficient sample size, control of confounding factors, inclusion of the relevant antibiotics, and availability of full-text articles. Data were analyzed using Comprehensive Meta-Analysis software (Biostat V2.2). Heterogeneity between studies was assessed using the I2 index, and a random-effects model was applied due to heterogeneity in the results.

The initial database search identified 241 studies. After removing 41 duplicates, 201 studies were considered for meta-analysis. After reviewing the titles and abstracts, 158 studies were excluded for not meeting the research criteria, leaving 16 studies for final analysis. This meta-analysis investigated the prevalence of resistance to erythromycin and clindamycin, resistance phenotypes, and the genes encoding antibiotic resistance in GBS isolates from pregnant women. All studies included were cross-sectional. The pooled resistance rates for erythromycin and clindamycin were 27.9% (CI95%: 16-43.9) and 28.4% (CI95%: 17-43.5), respectively. Continuous and inducible resistance phenotypes were observed in 17.5% (CI95%: 6.2-40.4) and 10.9% (CI95%: 4.7-23.2) of the isolates. The M and L phenotypes were found in 8.1% (CI95%: 3.9-16) and 4.8% (CI95%: 2.7-8.4) of the isolates, respectively. The prevalence of resistance genes, including ermTR, ermB, and mefA, was 34% (CI95%: 27.4-41.4), 24.5% (CI95%: 3-77.1), and 6.7% (CI95%: 3.9-11.4), respectively.

The study shows an increasing trend of erythromycin and clindamycin resistance in GBS isolates from pregnant women in Iran. Therefore, antibiotic susceptibility testing should be performed before prescribing these antibiotics to prevent the development and spread of resistant strains.

Clostridium difficile (Clostridioides difficile) is known as one of the main causes of pseudomembranous colitis and is considered an important enteropathogen in humans. Antibiotic use has been introduced as one of the most significant risk factors contributing to the prevalence and incidence of “Clostridium difficile nosocomial infection”. The aim of this study is to investigate the prevalence, antibiotic resistance, and genetic diversity of Clostridium difficile in semi-cooked ready-to-eat products in stores of Isfahan Province in Iran.

A total of 240 samples of semi-cooked ready-to-eat products, including potato kuku, herb kuku, cordon bleu, and chicken nuggets (each 60 samples), were randomly collected from stores of Isfahan Province between July 2020 and February 2021. Clostridium difficile was identified by culturing the samples in Clostridium difficile moxalactam norfloxacin. To determine the characteristics of the toxins, tcdA and tcdB genes were detected through multiplex polymerase chain reaction (M-PCR). The antibiotic sensitivity of the isolates was determined based on the minimum inhibitory concentration (MIC) test. The results were analyzed using chi-square test in SPSS software and P-value was considered significant at 0.05.

37 samples were infected with Clostridium difficile. The contamination rate was 13.3%, 20.0%, 11.6%, and 16.6% in potato kuku, herb kuku, cordon bleu, and chicken nugget, respectively. The highest contamination was related to the semi-cooked herb kuku product. TcdA and tcdB gene toxins were identified in 15 and 17 isolates of Clostridium difficile, respectively. Among Clostridium difficile strains, the highest level of resistance was seen for ampicillin and penicillin antibiotics, and the highest sensitivity was related to chloramphenicol and metronidazole.

Semi-cooked ready-to-eat products can be considered as potential sources of antibiotic-resistant Clostridium difficile. Thus, complete cooking process of semi-cooked ready-to-eat foods at appropriate temperature and time (85° C and 30 minutes) and following hygiene principles in food processing plants can prevent the probable gastrointestinal infections caused by strains of Clostridium difficile in consumers.

Klebsiella pneumoniae is an opportunistic pathogen that plays a major role in the development of nosocomial infections. One of the most important mechanisms of resistance to beta-lactam antibiotics is the production of beta-lactamase enzymes by this bacterium. The aim of this study was to determine the frequency of AmpC beta-lactamase producing clinical isolates of K. pneumoniae in Guilan and investigating the inhibitory effect thymol on these isolates.

Sixty isolates of K. pneumoniae were isolated and identified from clinical laboratories in Rasht during 2022. The pattern of antibiotic susceptibility in isolates was determined and beta-lactamase production was investigated using combined disk method. The presence of AmpC encoding genes including FOX, CITM and DHAM beta-lactamase genes in isolates was determined by PCR. The growth inhibitory effect of thymol on these isolates was determined using disck diffusion and broth microdilution and the efflux inhibitory effect was determined by Cartwheel methods.

Among tested isolates 46 (76.6%) showed multi drug resistant phenotype. Of the 22 phenotypically AmpC-producing isolates, CITM and DHAM genes were detected in 12 (20%) and 7 (11.66%) isolates respectively and 4 isolates had both CITM and DHAM genes at the same time. Thymol, showed growth and efflux inhibitory effects against all tested K. pneumoniae isolates.

The results of the present study suggest the necessity of finding a successful treatment option to prevent the spread of infections caused by AmpC producing K. pneumoniae. According to the results, the use of thymol can provide a basis for the development of a new treatment against multi-drug resistant Klebsiella pneumoniae.

Salmonella enterica subspecies enterica serotype Enteritidis (S. Enteritidis) is one of the leading causes of food-borne infections associated with the consumption of contaminated food products of animal origin in humans. gastroenteritis due to Salmonella is usually a self-limiting disease and does not require antibiotic therapy. However, antibiotic treatment for salmonellosis may be lifesaving for patients with severe infections.The objective of the present study was to examine antimicrobial resistance and determine its genetic basis in recently isolated S.Enteritidis strains.

During this study, in a cross-sectional descriptive study, 44 isolates of Salmonella enteritidis from human sources were investigated between September 2021 and September 2022.. After identification of the isolates using phenotypic and molecular methods by Multoplex-PCR, antibiotic resistance testing was performed according CLSI 2023. The strains were examined for the presence of qnrA,qnrB,qnrS and gyrA resistance genes by PCR.

 In a cross-sectional descriptive study, 44 isolates of Salmonella Enteritidis from human sources were investigated between September 2022 and September 2023. 100% of the strains were sensitive to imipenem and meropenem, and the sensitivity to the antibiotics ceftriaxone, ceftazidime, and cefotaxime were 93.2%, 90.9%, and 94.1%, respectively. 81.8% of isolates were sensitive to cotrimoxazole, sensitivity to ampicillin was 84.1%. Only 9.1% of isolates were sensitive to ciprofloxacin. Based on MIC results, 16 isolates had MIC between 0.002 and 0.064 and were placed in the sensitive area. 28 isolates had MIC between 0.125 and 0.5 and were placed in the area of reduced sensitivity. None of the strains resistant to disk diffusion method were resistant to MIC method. qnrA, qnrB and qnrS genes were not observed among ciprofloxacin resistant strains. All nalidixic acid resistant strains had gyrA gene.

In general, it was shown in this study that the resistance to the fluoroquinolone family is increasing among Salmonella Enteritidis isolates. On the other hand, we see a decrease in the sensitivity and prevalence of strains resistant to broad-spectrum cephalosporins among serovar Enteritidis, which is the drug of choice for extraintestinal infections.

Biofilm production is one of the reasons for drug resistance in bacteria. The aim of the present study was to synthesize niosomal structures containing tetracycline antibiotic and determine its effect on Klebsiella pneumoniae drug-resistant isolates in an effective treatment system.

In this laboratory study, nanoniosomes containing tetracycline (Tet-Nio) were synthesized using the thin layer hydration method, and the morphological characteristics of drug release was investigated. MIC (Minimum inhibitory concentration), crystal violet, MBEC (Minimum biofilm eradication concentration) tests were used to investigate the antibacterial and anti-biofilm effects against Klebsiella pneumoniae strains under study exposed to free tetracycline and Tet-Nio, and the expression of mrkA gene in 10 isolates using was evaluated by real-time PCR test. One-way analysis of variance was used to analyze the data.

Formulation No.2 with the particle size of 169.45±9.55 nm, polydispersity index (PDI) equal to 0.168±0.010, Zeta-potential equal to -24.55±1.63, entrapment efficacy equal to 75.31%±1.48%, and tetracycline drug release percentage in 48 hours equal to 45.34%±1.15% was chosen as the optimal formulation. The microbial test results showed that the Tet-Nio structure has more antibacterial effects than the free drug. Also, it was stated that the optimal formulation of Tet-Nio can significantly reduce the formation of biofilm in Klebsiella pneumoniae pathogenic bacteria by reducing the expression of the mrkA gene compared to the drug-treated group (p<0.001).

Niosomes containing tetracycline were able to inhibit biofilm formation in drug-resistant isolates of Klebsiella pneumoniae. Therefore, they can be used in clinical studies to deal with nosocomial infections caused by Klebsiella pneumoniae isolate.

In recent decades, the sudden emergence and rapid spread of infectious diseases has made it important to find new approaches in the field of prevention, identification and treatment of these diseases. Infectious diseases are always one of the basic challenges in the field of public health. For instance, the epidemics of the Zika virus, Ebola virus and recently the COVID-19 pandemic have shown the quick spread of an infectious disease from one geographical area to other parts of the world which could pose a serious threat to public health and the global economy. In this regard, the identification and study of prototype pathogens and priority pathogens are of particular importance as crucial strategies for the prevention, identification and production of therapeutic products for infectious diseases .
Prototype pathogens are viruses among virus families that have outbreak potential, and for this reason, the study of these pathogens enables the rapid development of research and the production of needed products in case of an epidemic. The results of this batch of research on SARS-CoV-1 and MERS-CoV led to the rapid development of a vaccine for SARS-CoV-2.
In addition to viral outbreaks, antibiotic resistance (AMR) in recent decades has led to the design and use of strategies to identify resistant strains of bacteria and control them. Therefore, simultaneously paying attention to pathogenic agents with the ability of outbreaks and having basic preparation to deal with them, as well as controlling antibiotic resistance, are known as priorities in the health field.
This study reviews the important steps regarding prevention outbreaks as well as the proper actions during them.

Mortality rate of Listeria infection is high and has been reported to be up to 30%. In this regard, the present study aimed to provide more information about food sources contaminated with the Listeria monocytogenes and offer suitable strategies to control this pathogen in supply centers, slaughterhouses, and processing centers.

Results of investigations on the prevalence of L. monocytogenes in food (seafood and aquatic products, red meat, poultry, and dairy products) during 2010-2023 were reviewed. In total, 61 acceptable studies were involved in the present research. After the selection of papers, their key results were extracted, including the prevalence of Listeria monocytogenes, cultivation method, sample type, and sampling location.

Listeria monocytogenes is prevalent in all types of seafood products, red meat, poultry, dairy products, and vegetables, as well as ready-to-eat and ready-to-cook foods. Consuming raw and undercooked foods contaminated with animal and human feces and direct contact with feces can cause Listeria infection in humans. L. monocytogenes is sensitive to amoxicillin, ampicillin, penicillin, and gentamicin antibiotics; therefore, these antibiotics can be used for listeriosis treatment.

In previous studies, the importance of traditional meat and dairy supply centers in L. monocytogenes transmission has been addressed to a lesser extent. It can be concluded that appropriate standards should be developed and applied to control this food pathogen by regulatory systems. In addition, regular and periodic monitoring of food products and providing necessary training to people about how to prevent food poisoning can play an effective role in reducing listeriosis.

Nosocomial infections are a global problem that has become a challenge in hospitals around the world since the 80s. One of the main sources of hospital infections is personnel. In this regard, the present study aimed to investigate the frequency, colonization rate, antibiotic resistance, and molecular types of Staphylococcus aureus in the personnel of key hospital departments, including emergency, infectious, Coronary Care Unit, and Intensive Care Unit Departments.

Nasal swab samples were collected from the personnel of the Emergency, Infectious, Coronary Care Unit, and Intensive Care Units Departments in the fall of 2021 and subsequently cultured. Confirmation of S. aureus strains was performed by biochemical tests, disk diffusion method, and agar screen test. Moreover, polymerase chain reaction for the evaluation of resistance genes was performed. Determination of agr group, determination of SCCmec type, and checking the presence of pvl, tst, and etc genes were also performed.

In total, 75 out of 214 staff nasal swab samples contained S. aureus. Prevalence of methicillin-resistant S. aureus was 65.3% confirmed by PCR test results. Based on the study of SCCmec types in MRSA strains, the most common type was SCCmecIII. Among the agr groups, type I was the most common, and in terms of the abundance of pvl, tsst, and etc genes, a relatively high prevalence was observed.

Due to the increased level of personal and environmental health in hospitals, s. aureus colonizing the noses of personnel are more pathogenic and resistant due to the natural selection of strains. Therefore, they can cause more severe diseases following transmission to the patients.

Klebsiella pneumoniae is one of the essential types of human pathogenic bacteria. The emergence of antibiotic resistance has caused numerous treatment problems for its elimination. The present study aimed to assess the antibiotic resistance pattern of K. pneumoniae bacteria in patients admitted to the intensive care unit (ICU) of Shahid Rahimi Hospital in Khorramabad in 2022.

This cross-sectional descriptive study was conducted on 120 patients admitted to the ICU of Shahid Rahimi Khoramabad Hospital in 2022. After collecting K. pneumoniae isolates, the antibiotic resistance pattern of all isolates was evaluated. Thereafter, the relationship between antibiotic resistance and different variables was analyzed using SPSS software (version 25).

In this study, the mean age of patients participating was 55.09±26.44 years. The most isolated strain of K. pneumoniae was obtained from urine samples (48.3%). The highest rate of antibiotic sensitivity was to amikacin (65.8%), gentamicin (50.8%), and ciprofloxacin (49.2%), while the highest rate of antibiotic resistance pertained to cefixime (68.3%), cefotaxime (66.7%), and ceftriaxone (60.8%). The pattern of antibiotic resistance showed a significant relationship with inpatient ICU, surgical ICU, general ICU, internal ICU, emergency ICU, and pediatric ICU (P < 0.05).

By specifying the pattern of antibiotic sensitivity in the ICU in the investigated area and reporting it to the doctors, the obtained results can be taken into account in experimental treatments, which in itself causes a better response from the patients to the received medicine and a reduction in antibiotic resistance in ICUs.

Urinary tract infection is one of the most important infectious diseases. Beta-lactam antibiotics, especially the third and fourth generations of cephalosporins, are effective in treating this infection. The production of beta-lactamase enzyme by bacteria is the most important mechanism of resistance to various beta-lactam antibiotics, which poses a serious threat to the use of these drugs in the future. The aim of this study is to investigate the presence of new beta-lactamases in Enterobacteriaceae isolated from urinary tract infections.

In this cross-sectional descriptive research, 100 isolates of Enterobacteriaceae were isolated from urine samples collected from the hospitals and laboratories of Alborz province. The isolates were identified by standard biochemical and microbial tests. The pattern of antibiotic resistance of the isolates to 11 different antibiotics was investigated by the Kirby Bauer method. The isolates were analyzed phenotypically in terms of β-lactamase production (NDM-1). In the case of isolates with β-lactamase blaNDM-1, PCR was done with the help of specific primers, and finally the PCR product was sequenced and analyzed.

The pattern of antibiotic resistance was observed as follows: ampicillin (85%), imipenem (70%), kanamycin (66%), cefotaxime (51%), ceftriaxone (51%), tetracycline (50%), ceftazidime (% 49), ciprofloxacin (46%), neurofloxacin (36%), gentamicin (29%), meropenem (27%). The results of PCR showed that 2% of the isolates had blaNDM-1 gene.

The increase of antibiotic resistance in clinical isolates and the emergence of new beta-lactamases warn that the policy of using antibiotics to treat bacterial infections should be changed.

Due to emerging antibiotic-resistant bacteria, finding effective alternative antimicrobials to combat the bacteria is unavoidable. Bacteriophage therapy as a biologic and highly potentiated therapeutic approach was considered recently. This study aimed to isolate lytic bacteriophage(s) against multi-drug resistant clinical isolates of Klebsiella pneumonia and evaluate the morphological and biological characteristics as candidates for phage therapy.

Obtained clinical isolates from Shahid Madani Hospital in Tabriz, were confirmed as K. pneumoniae, and an antibiotic sensitivity test was performed using the standard disk diffusion method. Then, the isolation of lytic bacteriophages against 16 selected antibiotic-resistant bacterial isolates was carried out. Briefly, samples for phage isolating were gained from sewage water and centrifuged. The supernatant was filtered using a 0.45 µm Filter, mixed with fresh tripton soy broth medium and magnesium sulfate and incubated at room temperature. Then, the solution was mixed with chloroform and evaluation of plaque formation was performed using the agar bilayer technique. Genomes of the bacteriophages were subjected to molecular analysis using Hind III and EcoRV enzymes. Host range determination of the isolated bacteriophages was evaluated using spot test and agar bilayer techniques. Three bacteriophages with a broader host range than others were selected for more characterization. One step growth curve of the phages was drawn and their latent period and burst size were investigated. Then, the stability and survivability of the isolated lytic bacteriophages to different temperatures (-20, 37, 50℃), different rates of pH value (3,4,5,7,9,11,12), and also UV radiation were evaluated. Finally, morphological characteristics of bacteriophage with the broadest host range (PKpMa2/20) were investigated using electron microscopy.

36 clinical bacterial isolates were confirmed as K. pneumoniae based on standard biochemical tests. In the antibiotic susceptibility assay, it was revealed that the highest and lowest rates of antibiotic resistance belonged to cefazoline (80%) and tobramycin (26%) respectively. Isolation of bacteriophages against all 16 selected isolates was successfully performed. After the extraction of the genomes of the phages, a high variety of genome sequences was detected according to molecular analysis. In host range determination, PKpMa2/20 had lytic activity against 11 of 15 isolates. In a study of the one-step growth curve of the phages, with a broader host range than other isolated bacteriophages, latent periods were shown 10, 10, and 15 min and their burst size were 350, 210, and 180 pfu/ml respectively. All of the phages showed appropriate stability in temperatures of -20 and 37 ℃. In the temperature of 50℃, the survivability of PKpMa2/20 was higher than two other phages. Also, PKpMa2/20 was stable in the pH range of 3-12; in the pH value of 3, two other phages stability was ceased but PKpMa2/20 showed appropriate lytic activity. In electron microscopy, PKpMa2/20 had a short tail length of 10 nm and a head with a diameter of about 60 nm that possibly belonged to the family Podoviridae. 

Based on appropriate lytic effects, latent period, and burst size of the three isolated bacteriophages in the current study, especially PKpMa2/20, and also, their high stability to different temperatures, pH, and UV radiation, they could be considered as candidates for phage therapy to control resistant strains of K. pneumoniae infections but for the therapeutic use of theses phages, more molecular analysis is needed.