hamidreza goli

Acinetobacter species have emerged as major causes of nosocomial infections. Acinetobacter baumannii, the most common clinical subspecies, can cause a wide range of nosocomial infections, including pneumonia, bloodstream infections, and wound infections. These infections are often associated with high mortality rates due to the increasing prevalence of drug resistance among these bacteria. The production of β-lactamases is a significant mechanism of resistance to β-lactams. The transcription of theseβ-lactamase genes is enhanced by various insertion sequences (ISs) located nearby. The insertion sequences most commonly associated with carbapenem genes in multidrug-resistant Acinetobacter baumannii isolates are ISAba1, ISAba2, ISAba3, ISAba4, and IS18. This study aimed to evaluate the drug resistance patterns and molecular detection of ISAba1 and ISAba2 insertion sequences in A. baumannii isolates recovered from hospitalized patients in Sari teaching hospitals.

This study was conducted over six months, from March 2022 to August 2022, in Sari teaching hospitals. Ninety A. baumannii isolates were collected from various clinical specimens of hospitalized patients. To confirm the species of A. baumannii, various phenotypic tests such as TSI, oxidase, MR/VP, OF, urea, citrate, and SIM were employed. The antibiotic susceptibility pattern of the isolates was evaluated using the disk diffusion method according to the CLSI 2021 guidelines. The minimum inhibitory concentration (MIC) of colistin was determined using the micro broth method. To evaluate the presence of ISAba1 and ISAba2 genes, the Polymerase Chain Reaction (PCR) method was performed using specific primers. Data were analyzed using SPSS version 22 software. The chi-square test was used to determine significant differences, with a P-value less than or equal to 0.05 considered statistically significant.

The results of this study showed that A. baumannii isolates had a high level of resistance to several antibiotics, including ciprofloxacin, imipenem, doripenem, cefepime, ceftazidime, piperacillin/tazobactam, and piperacillin, with all isolates (100%) being resistant to these antibiotics. However, the highest susceptibility was observed for the antibiotic colistin (98.8%). Additionally, the frequencies of ISAba1 and ISAba2 genes among the isolates were 95.5% and 81.1%, respectively, indicating a high prevalence of these genetic elements among the study isolates.

The results of this study indicate a high susceptibility of isolates to the antibiotic colistin, but due to the risk of resistance development and nephrotoxicity, it should be used with caution. The findings suggest that the presence of insertion elements such as ISAba1 and ISAba2 plays a significant role in increasing the expression of drug-resistance genes and their transfer in Acinetobacter baumannii. This can help explain the high prevalence of drug resistance in these bacteria and highlights the importance of detecting and controlling these factors to reduce nosocomial infections. Therefore, identifying and controlling these factors can be an effective step in improving prevention and treatment methods for infections caused by A. baumannii.

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.

Pseudomonas aeruginosa is an opportunistic nosocomial pathogen, which is resistant to different groups of antibiotics. Infections caused by this organism due to antibiotic resistance may ultimately cause high mortality. The ability of this microorganism to produce pathogenic factors such as alginate, proteases, pyocyanin, rhamnolipid, phospholipase C, the presence of pili, and the ability to form biofilm and colonization have made this bacterium one of the most important pathogens. Considering that alginate is one of the important pathogenic factors of this microorganism which mainly algA, algC, and algD genes encode enzymes necessary for the leading biosynthesis pathway of alginate-GDP-mannuronic acid. Therefore, in the current study, we investigated the frequency of the algD gene in P. aeruginosa isolated from patients hospitalized in Mazandaran hospitals using specific primers by PCR method.

According to the results of past studies and using the sample size formula to calculate the prevalence and considering the maximum error of 0.05, the confidence level of 0.95, the ratio of 0.97, and the sample size of the unlimited population was estimated to be 100 isolates. Clinical isolates of P. aeruginosa were collected from different laboratories of Mazandaran educational hospitals. After collecting the clinical isolates of P. aeruginosa and definitively identifying the bacteria by performing routine biochemical tests, the antibiotic resistance pattern of the isolates was checked with Agar Diffusion Disk. In the next step, we extracted the DNA of P aeruginosa strains by alkaline lysis method by adding sodium dodecyl sulfate and NaOH. Finally, a PCR test was performed using the specific primer of the algD gene. Then, the PCR product was evaluated using a UV Transilluminator device. Data were analyzed using SPSS software.

100 isolates of P. aeruginosa were isolated from 100 hospitalized patients. These isolates were collected from five medical educational hospitals of Mazandaran province, which were as follows: Imam Khomeini Hospital in Sari (40 isolates), Razi Hospital in Qaemshahr (22 isolates), Bo Ali Sina Hospital in Sari (17 isolates), Zare Psychiatric and Burn hospital in Sari (11 isolates), and Fatemeh Zahra heart hospital in Sari (10 isolates). Most of the clinical isolates of P. aeruginosa in the present study were obtained from sputum samples (37/100) and in second place from urine samples (26/100) of patients. 98 isolates had the algD gene. 26% of isolates were resistant to Piperacillin, 39% of isolates to Aztreonam, 27% of isolates to Ceftazidime, 31% of isolates to Imipenem, 39% to Tobramycin and 41% to Ciprofloxacin. All clinical isolates resistant to studied antibiotics carried the algD gene. Only two isolates of the sensitive strains of this organism in each group of antibiotics lacked the desired gene.

The results of the present study show that the algD gene is present in most of the clinical isolates of the P. aeruginosa strain obtained from medical education centers in Mazandaran. On the other hand, the high prevalence of this organism and the high resistance to antibiotics and multiple drugs observed in the current study and previous studies have turned the treatment of infections caused by P. aeruginosa into a serious and complex problem. Finally, considering that the algD gene plays a significant role in the formation of biofilm and antibiotic resistance, the results of the current study also confirm this finding.

Due to the significant increase antibiotic-resistant bacteria, this study aimed to determine the frequency of bacteria causing respiratory, blood, and wound infections in patients admitted to the Rouhani Medical Center in Babol and to determine their antibiotic resistance pattern.

This study was carried out on 267 isolates collected from 158 blood samples, 60 respiratory samples, and 49 wound samples prepared from patients referred to Rouhani Hospital in 2022. The bacteria detected by the hospital laboratory were transferred to Mazandaran University of Medical Sciences and confirmed in the microbiology laboratory of the Faculty of Medicine. Then, the antibiotic susceptibility pattern of the isolates was analyzed by the disk agar diffusion method and interpreted according to the guidelines of the Institute of Clinical and Laboratory Standards. The results were analyzed using SPSS-19 statistical software.

The highest prevalence of bacteria isolated in this study (20.59%) was related to Escherichia coli and the lowest prevalence (1.12%) was related to Proteus mirabilis. Among 158 strains isolated from blood samples, E. coli (26.58%) was the most common bacteria. Among the 60 isolates collected from respiratory samples, Acinetobacter baumannii (23.33%) was the most prevalent and among the 49 strains isolated from wound samples, Staphylococcus aureus (30.61%) was the most common bacteria identified in this study. The antibiotic resistance pattern of the gram-positive bacteria identified in this study showed that the highest resistance (78.43%) of S. aureus strains was against tetracycline, while 3.92% of the isolates were resistant to linezolid. The resistance of coagulase-negative staphylococci and Enterococcus faecalis to the tested antibiotics varied between 12.5% and 83.33%. The amount of antibiotic resistance of Gram-negative isolates identified in this study also varied between 12.5% and 75.47%. The antibiotic resistance of S. aureus isolated from blood, respiratory, and wound samples to the tested antibiotics was 3.57% to 85.71%, 25% to 62.5%, and 25% to 62.5%, respectively, while tetracycline and linezolid were the least and most effective drugs against this bacterium. Among the gram-negative bacteria isolated from blood, respiratory, and wound samples, 34.51% to 61.94%, 41.66% to 64.58%, and 41.66% to 64.58% of the isolates were resistant to tested antibiotics, respectively, while piperacillin and imipenem were the least and most effective drugs.

The emergence of resistant strains in hospitals is related to continuous contact with all kinds of antibiotics, and the implementation of exact care strategies can lead to the prevention of drug resistance and spread. The most important factors to achieve these goals are the exact control of hospital care, prevention of hospital infections, and compliance with the principles of antibiotic use. Therefore, the essential role of infection control methods in hospitals, avoiding the unnecessary prescription of antibiotics, especially in surgical prophylaxis, proper isolation of patients, and appropriate use of laboratory facilities for the rapid diagnosis of microorganisms in each hospital is emphasized. The diagnosis and report of the antibiotic resistance pattern of common organisms in the region can be considered in empirical treatments to prevent the emergence of antibiotic resistance and high treatment costs for patients and medical centers.

Antimicrobial property is one of the important features of sealers, which plays an essential role in limiting microorganisms from the root canal system. This study was conducted to investigate the antimicrobial properties of EndosealMTA, Sure seal root, and AH26 sealers on Enterococcus faecalis bacteria.

In this study, ceramic sealers Endoseal MTA, suersealroot, and resin sealer AH26 were used. Each of these sealers was placed in wells in the agar medium for 10-15 minutes to spread and then immediately incubated at 35±2°C for 24 hours. Statistical analysis was performed using SPSS (V.22), with the application of Shapiro-Wilk, Kruskal-Wallis, and ANOVA tests.

The highest mean halo of non-growth was related to the Endoseal MTA group. The antimicrobial property of Suresealroot sealer was lower compared to AH26 sealer, but this difference was not statistically significant. (P=0.368). The antimicrobial property of Endoseal MTA sealer was higher compared to AH26 sealer, but this difference was not statistically significant (P=0.368). The antimicrobial properties of Suresealroot sealer were lower compared to Endoseal MTA, but there was no statistically significant difference (P=0.48).

Ceramic sealers Suresealroot, Endo seal MTA and AH26 resin sealer showed antimicrobial properties against Enterococcus faecalis; But the antimicrobial properties of Ceramic Sealers were not different from resin sealer on Enterococcus faecalis

The main viral causes of acute respiratory diseases (ARDs) include influenza viruses A and B, respiratory syncytial virus (RSV), adenovirus (ADV), rhinovirus, and parainfluenza viruses (PIV). This study aimed to investigate the prevalence of respiratory RSV, ADV and rhinovirus in patients with flu-like symptoms admitted to Mazandaran province health centers in north of Iran.

This study was conducted in Mazandaran province from 21 December 2018 to 21 March 2019. The nasopharyngeal samples were collected from the patients with flu-like symptoms admitted to the health centers. ADV, RSV, influenza virus, and Human Rhinovirus (HRV) were detected by PCR and reverse-transcriptase PCR. Then, the products were visualized by gel electrophoresis on 1.5% agarose under UV light.

In the present study, 26 samples (26%) contained the ADV, while 9% and 5% of the samples were positive for RSV and HRV, respectively. Also, co-infection with influenza virus was identified in 12 patients, while 8 (66.66%) patients had a co-infection of influenza virus and ADV, simultaneously. Also, 2 (16.66%) co-infected patients infected by RSV and influenza virus, as well as the rate of HRV co-infection with influenza virus. There were no triple or more co-infections in this study. Moreover, one death was reported among the patients with co-infection of influenza virus and adenovirus, while other co-infected patients were cured.

The findings will help public health officials and physicians to improve respiratory virus infection control strategies. Further molecular monitoring of respiratory viruses should be performed to investigate their epidemiological and clinical features.

Increased resistance to β-lactams is one of the most important considerations about Pseudomonas aeruginosa. This study aimed to investigate the prevalence of blaOXA-2 and blaOXA-10 genes in β-lactam-resistant P. aeruginosa.

In this study, 100 clinical isolates were collected, and β-lactam-resistant strains were identified using the disk agar diffusion test. Bacterial DNA was extracted by the sodium dodecyl sulfate method, and the polymerase chain reaction was used to identify blaOXA-2 and blaOXA-10 β-lactamase genes.

In total, 43 isolates were resistant to at least one of the β-lactams tested. Piperacillin-tazobactam and aztreonam were the most and least effective antibiotics, respectively. The resistance rate to a panel of β-lactams ranged from 12% to 37%. The highest rate of antibiotic resistance was related to wound and catheter specimens in burn and intensive care units. A significant relationship was observed between β-lactams resistance and the presence of blaOXA-2 and blaOXA-10 genes. Among 43 resistant isolates, 100% and 83.72% carried the blaOXA-2 and blaOXA-10 genes, respectively.

High β-lactam resistance rates and prevalence of blaOXA-2 and blaOXA-10 in this study indicate these enzymes' significant role in resistance to β-lactams, possibly due to overuse of these antibiotics and their easier access.

Background and

Emergence of multidrug resistance (MDR) among Streptococcus agalactiae isolated from pregnant women and the presence of polysaccharide capsules in these strains play a significant role in pathogenicity. Therefore, the aim of this study was to investigate the prevalence of antibiotic resistance, multidrug resistance, and Ia and Ib capsular types in these strains.

Vaginal samples were transferred to Todd-Hewitt Broth medium. After 24 hours, they were inoculated on the blood agar medium, and then the bacteria were identified using standard methods. The antibiotic resistance pattern of the isolates was determined by the disk agar diffusion method. Then, the bacterial DNA was extracted and the capsular genes were identified using PCR method.

The prevalence of colonization in pregnant women was 23.25%. Tetracycline with 94.33% resistance rate was the least effective drug, while 78.3%, 81.13% and 83.01% of the isolates were non-susceptible to ofloxacin, erythromycin and quinupristin-dalfopristin, respectively. Also, 78.3% of the isolates were sensitive to penicillin. Meanwhile, 94 (88.7%) isolates were MDR, while 20 (18.86%) isolates and 32 (30.18%) isolates had the Ia and Ib capsular types, respectively.

Penicillin is a suitable drug for prophylaxis in high-risk pregnant women in this region. The high prevalence of MDR strains indicates the lack of proper management of antibiotics. In addition, the high prevalence of capsular types Ib and Ia, especially in MDR strains, shows the importance of these serotypes for designing capsular vaccines.

Ventilator-associated pneumonia (VAP) is of special importance among nosocomial infections. We aimed to study the bacterial profile of VAP and their drug susceptibility pattern among intensive care unit patients at teaching hospitals affiliated with Mazandaran University of Medical Sciences.

In this retrospective cross-sectional study, the records of patients in the intensive care unit with ventilator-associated pneumonia were reviewed. After the growth of the bacteria, the colony identification of the grown bacteria were done based on microbiological and biochemical standard tests. To investigate the antimicrobial susceptibility pattern of isolates, the disk diffusion method was used according to the CLSI guidelines.

Out of 107 patients, 14 (13%) had a history of hospitalization over the last three months. The most common underlying diseases were ischemic heart disease (IHD), hypertension, and diabetes. The most common causes of hospitalization included cardiac diseases, COVID-19, and sepsis. The most common microorganism isolated was Enterobacter (23.4%), and the least abundant microorganisms were Proteus (n=1) and Staphylococcus saprophyticus (n=1). In general, colistin was the most sensitive among the examined gram-negative organisms.

Identifying the pattern of antibiotic resistance and the risk factors for ventilator-associated pneumonia are effective in delivering more efficient treatments and reducing the complications of this disease. Local epidemiological data should be collected at all centers as this information guides the initial empirical treatment with antibiotics, thereby preventing the development of more resistant strains. All these measures will reduce the morbidity and mortality of ventilator-associated pneumonia.

Plaque accumulation on the surface of removable orthodontic appliances could lead to dental caries, periodontitis, and fungal infections.This study evaluated the effectiveness of antimicrobial photodynamic therapy (aPDT), chlorhexidine (CHX), sodium fluoride (NaF), and hydrogen peroxide (H2O2) for the disinfection of acrylic resin.

In this in vitro experimental study, 100 acrylic resin specimens were randomly divided into five groups (n = 20 each): Enterococcus faecalis, Streptococcus mutans, Streptococcus salivarius, Streptococcus sanguinis, and Lactobacillus acidophilus. Each group was immersed separately in 5 mL of microbial suspension. They were then incubated until biofilm formation on their surface. Of each microorganism, one biofilm sample in phosphate-buffered saline was considered as negative control, and other biofilm samples (n = 80) were subjected to aPDT with curcumin, 0.12% CHX (positive control), 1% H2O2, and 0.2% NaF. Finally, the number of colonies was counted. Data were analyzed by the Kruskal-Wallis and Mann-Whitney tests, two-way ANOVA, and Bonferroni adjustment at a significance level of 0.05.

The interaction effect of the treatment modality and type of microorganism was significant on the microbial count (effect size: 0.91, P < 0.05). Maximum bacterial proliferation was noted in the following combinations: NaF/E. faecalis, H2O2/E. faecalis, and H2O2/S. salivarius. Microorganisms had no or insignificant growth and proliferation in the aPDT and CHX groups.

The results supported the optimal antimicrobial efficacy of PDT which was comparable to that of CHX. aPDT showed superior antimicrobial efficacy to NaF and H2O2 for the disinfection of acrylic resin.

Buxus hyrcana Pojark. has been traditionally used for the treatment of skin disorders including wound injuries and recent studies have shown the therapeutic potential of some Buxus species in healing skin wounds. In this study, the effect of an ointment containing methanolic extract of B. hyrcana leaves was evaluated on the full-thickness wound healing in a rat model.

The full-thickness wound was made with a scalpel on the dorsum cervical area of 32 Wistar rats (weighing 250-300 g). The animals were randomly divided into four groups: I; control, II; ointment base (eucerin), III; 1 % phenytoin cream, and IV; 5 % B. hyrcana methanolic extract ointment. For histopathological assessment, wound criteria were evaluated on the 12th day of treatment according to the Abramov score method. The collagen fiber deposition in the skin tissue was determined using Masson’s trichrome staining. The spectrophotometric analysis was performed to evaluate the total phenol and total flavonoid content of the extract.

Based on macroscopic observations, herbal ointment increased wound closure in the treatment group compared to the control group. In this way, the collagen deposition, epidermal and keratin formation, neovascularization, and fibroblast maturation increased significantly (P<0.05) with the herbal ointment, the same as the phenytoin group. The extract did not show any antimicrobial effect using the disc agar diffusion method.

The observed wound-healing effect of B. hyrcana seems to be mainly due to the presence of flavonoid compounds in the plant extract.

Garlic and cinnamon extracts, like fluoride varnish, play a role in caries control due to their antimicrobial effect and controlling demineralization. This analytical laboratory study was conducted in 2021 to investigate the antimicrobial effect of garlic and cinnamon extracts compared with fluoride varnish in controlling the infection of oral Lactobacillus acidophilus and Streptococcus mutans.

The disk diffusion, minimum inhibitory concentration and the minimum bactericidal concentration tests were used to check the antimicrobial effect. Ampicillin and Erythromycin discs were used for positive control and sterile physiological serum was used for negative control. Data were analyzed using analysis of variance (ANOVA) and Bonferroni post hoc test.

In disk diffusion test, cinnamon along with fluoride varnish (10.0±1.0mm) caused a significant increase in the diameter of the growth inhibition halo of L. acidophilus (P<0.001), However, the largest growth inhibition halo diameters in L. acidophilus and S. mutans were associated with garlic-cinnamon-varnish (12.0±1.58mm) and fluoride varnish (9.0±0.71mm), respectively. In both strains, the antimicrobial effect of garlic extract was significantly lower than other compounds (P<0.001). The most inhibitory and bactericidal effects were associated with fluoride varnish seen in S. mutans.

According to this study, cinnamon and fluoride varnish has a synergistic antimicrobial effect against L. acidophilus in laboratory conditions. Also, cinnamon extract due to similar effects to fluoride varnish, can be useful as an alternative agent in controlling and preventing dental caries.

Urinary tract infections (UTIs) are among the most common infections in both outpatients and inpatients worldwide. Due to the widespread use of empirical antibiotic therapy, the resistance rate to bacteria causing UTIs has significantly increased. Therefore, the present study was designed to investigate the pattern of drug resistance in Escherichia coli strains isolated from patients with UTIs referred to the educational centers of Mazandaran University of Medical Sciences.

In this cross-sectional study, 100 urine samples completely randomly were taken from patients with UTI. Patient characteristics including age, gender, outpatient and/or inpatient were collected from patients' clinical records and laboratories data services. After confirmation of E. coli strains, antibiogram was performed by disk diffusion method according to Clinical Laboratory Standards Institute (CLSI) instructions.

Out of 100 positive urine culture samples, the highest prevalence of E. coli causing UTI was seen in the female (83%) and outpatient (53%) groups. The age range of the patients was between 0 (6-month-old) and 95 years. The highest resistance was reported against ampicillin (66.6%) and the lowest resistance to imipenem (1%), followed by cefoxitin (1.2%) and gentamicin (1.7%), while resistance to amikacin and tobramycin was not found. Of 100 E. coli isolates, 44% were associated with multidrug resistance phenotype; 32 cases of which were women and 25 cases were for hospitalized patients.

Following the overuse and misuse of antibiotics, drug resistance is increasing over time. Due to high rates of resistance to ampicillin, cotrimoxazole and cephalosporins, especially cefazolin and cefotaxime, the use of these drugs in the treatment of UTIs will not be a good option. Our data show that carbapenems and aminoglycosides should be considered as an option for first-line treatment of hospitalized patients with UTIs, in the study area.

Production of beta-lactamase enzymes by bacteria, especially Extended-spectrum β-lactamases (ESBLs) is one of the major problems worldwide. ESBLs are mostly located on bacterial plasmids and it is recognized that SHV, TEM, and CTX-M are prevailing among them. The aim of this study was to determine the ability to produce ESBLs genes based on molecular method among non-fermenting Gram-negative bacteria (Pseudomonas aeruginosa and Acinetobacter baumannii) isolated from hospitalized patients in Mazandaran province, Iran.

In this cross-sectional descriptive study, 81 non-fermenting bacterial isolates were collected. The isolates were tested for antibiotic susceptibility according to CLSI guidelines. Molecular identification of blaSHV, blaTEM, and blaCTX-M genes was performed using specific primers and polymerase chain reaction (PCR) method.

Of 81 non-fermentative bacteria isolated, 49 (60.5%) isolates of A. baumannii were detected and 32 (39.5%) isolates were confirmed as P. aeruginosa. The prevalence of identified genes in these isolates was as follows: 26% blaSHV, 19% blaTEM, and 12% blaCTX-M in P. aeruginosa and 11% blaTEM, 8% blaCTX-M, and 4% blaSHV in A. baumannii.

ESBL positive strains of P. aeruginosa and A. baumannii are increasingly found in hospital isolates. Their high ability to pass resistant genes to other clinical strains requires their quick detection in clinical laboratories.

 Computers and other electronic devices are a requisite aspect of people’s lives globally for multiple purposes, including education, entertainment, and communication.

 This study investigated the bacterial contamination of desktop computer keyboards (as a reservoir of pathogens) in different departments of Mazandaran University of Medical Sciences, Sari, Northern Iran, from September 2018 to February 2019.

 In this descriptive cross-sectional study, samples were obtained from computer keyboards with sterile swabs and cultured on blood agar and eosin methylene blue agar. Standard microbiological methods were used to identify bacterial isolates. Then, the antimicrobial susceptibility testing of the isolates was performed using the Kirby-Bauer method based on the CLSI procedure.

 In total, 58 bacterial strains were isolated from the collected samples. The isolates included 23 (39.7%) Staphylococcus epidermidis, 15 (25.9%) Staphylococcus aureus, 14 (24.1%) Bacillus spp., 3 (5.2%) Klebsiella pneumoniae, 2 (3.4%) Pseudomonas aeruginosa, and 1 (1.7%) Escherichia coli. All Gram-positive bacteria were resistant to penicillin, whereas the most resistance rate among Gram-negative bacteria was observed against ciprofloxacin, ceftazidime, and cephalothin.

 Due to the presence of opportunistic pathogens on computer keyboards, personal hygiene and periodic cleaning of keyboards with disinfectants is necessary to prevent the further spread of these bacteria.

Klebsiella pneumoniae is an important cause of nosocomial infections. The present study sought to detect resistance status and the frequency of multidrug‑resistant (MDR), extensively drug‑resistant (XDR), and pandrug‑resistant (PDR) K. pneumoniae strains isolated from hospitalized patients.

Confirmation of K. pneumoniae isolates was performed by polymerase chain reaction (PCR) for rpoB fragment. Drug susceptibility was done by disk diffusion method based on the Clinical and Laboratory Standards Institute. According to the susceptibility pattern, the strains were categorized as MDR, XDR, and PDR.

On the basis of PCR results, rpoB gene was identified in all 100 K. pneumoniae isolates. Most K. pneumoniae strains showed a high percentage of resistance against ampicillin‑sulbactam (93%). On the other hand, tigecycline and fosfomycin were active against 100% and 90% isolates, respectively. The multiple resistance analysis of the strains showed that 58% and 13% of isolates were identified as MDR and XDR, respectively. Overall, no PDR isolate was detected in any tested strains.

Our results demonstrated that the vast majority of K. pneumoniae strains indicated the MDR phenotype including a high resistance rate to common antibiotics. Therefore, it is suggested to implement antimicrobial susceptibility testing before prescribing, to assist in selecting the most effective agents within the antimicrobial categories for the treatment of infections with multiple antibiotic‑resistant K. pneumoniae strains in hospitalized patients.

Dental caries is one of the most common bacterial diseases in childhood. Using proper dentifrice is suggested to reduce the incidence of this disease. The aim of this study was to investigate the antimicrobial effects of different brands of children's dentifrice available in Iran’s market on Streptococcus mutans (PTCC1683) and Lactobacillus acidophilus (PTCC4356) strains.

After culturing standard bacterial strains, different kids dentifrice brands, including Irox, Bath, Misswake, Colgate, Oral-B, Bencer, and Frice were prepared by distilled water in 2 mg/ml and 4 mg/ml and added to pits in cultures medium. Then, the samples were incubated at 37°C for 24-48 hours and diameter of the antibacterial inhibitory haloarchaea was reported in millimeters. T-test was used for statistical analysis.

All dentifrices recorded an inhibitory haloarchaea diameter of 3-25 mm (except Bath and Irox at 2 mg/ml against S. mutans, 0 mm). The antibacterial strength of dentifrices was as follows: Oral-B> Colgate> Frice> Bencer> Misswake> Bath> Irox. At 4 mg/ml, the diameter of haloarchaea against L. acidophilus was approximately twice than that of S. mutans. The mean haloarchaea diameter was not significantly different between the control group and dentifrices at 4 mg/ml against S. mutans (P= 0.080). In other conditions, the mean diameter of haloarchaea in dentifrices was lower than that of the control group (P≤0.001).

In this in-vitro study, Oral-B and Colgate (sodium fluoride 500 ppm) had the highest antibacterial effect and Bath and Irox (sodium monofluorophosphate 500 ppm) had the lowest antibacterial strength against the studied microorganisms. In addition, except for Bath and Irox, other dentifrices in various concentrations had desirable antibacterial properties.

 Hospitals niche as a source and repository for microbial infections are playing a significant role in the health of hospitalized patients. Bacteria are playing an essential role in human and animal blood infections and meningitis. The prevalence of bacterial agents and their susceptibility patterns are fundamental goals of current research.

 Sampling was carried out in two main educational hospitals, Sari City, Iran, from April 2016 to March 2017. After traditional biochemical tests, susceptibility testing of isolates was performed taking advantage of Kerby-Bauer. Subsequently, the frequency of related bacterial agents to meningitis and bacteremia and their susceptibility patterns were analyzed.

 Frequencies of bacterial isolates in Bouali and Imam Hospitals for meningitis (1.9%, 3.5%), bacteremia (31.9%, 26.3%), and urinary tract infection (UTI) were screened (66.2%, 70.1%). Staphylococcus aureus (41.7%) and Streptococcus pneumoniae (45%) were the highest isolates of meningitis in the mentioned hospital. These values to bacteremia were as follows: Gram-negative Staphylococci (30.7%), Escherichia coli (30%). Coagulase- negative Staphylococci isolates recovered from meningitis were completely sensitive to ciprofloxacin and Gentamycin. In addition, P. aeruginosa, Klebsiella and Acinetobacter spp showed higher than 90% resistance against ampicillin. E. coli, Klebsiella spp and S. aureus showed 100% resistance to amoxiclav; while Klebsiella spp were completely sensitive to amoxiclav.

 Given the bacterial isolates detected from hospital wards and following the findings prompt diagnosis method is essential to control infections and the proper use of effective antibiotics.

Pseudomonas aeruginosa is an opportunistic pathogen and the second leading cause of nosocomial infections, especially in the intensive care unit (ICU), and is responsible for high mortality rates. The aim of this study was to determine the pattern of antibiotic susceptibility and prevalence of multiple drug resistance strains of P. aeruginosa isolated from hospitalized patients in Mazandaran province, Iran 2020.

In this descriptive cross-sectional study, 80 strains of P. aeruginosa were collected from different clinical specimens. Antibiotic susceptibility of the isolates was determined by disk agar diffusion method according to the instructions of Clinical and Laboratory Standards Institute (CLSI). Finally, based on the resistance pattern, multi-drug resistant (MDR), extensive-drug resistant (XDR), and pandrug-resistant (PDR) isolates were identified.

Out of 80 P. aeruginosa isolates, the highest number of samples was collected from ICU (58.75%). The highest antibiotic resistance was observed against ticarcillin-clavulanate (95%), meropenem (80%), and ceftazidime (75%). Piperacillin-tazobactam and cefpime showed the highest inhibitory effect against P. aeruginosa isolates with 57.5% and 51.25% sensitivity, respectively. Altogether, 88.75% and 46.25% of the isolates were categorized as MDR and XDR, respectively. In this study, PDR phenotype was not observed among our tested strains.

This study showed that P. aeruginosa strains are resistant to a wide range of antibiotics. Given the role of this bacterium in nosocomial infections, especially in ICU, it is necessary to take immediate measures for timely identification, definitive treatment with appropriate antibiotics, and preventing the spread of resistant strains of this bacterium.

Although it is shown that probiotic agents might reduce Streptococcus mutans, no study has evaluated this effect in the form of probiotic mouthrinse. The purpose of this study was to compare the effect of probiotic experimental mouthwash Lactobacillus plantarum versus sodium fluoride and placebo mouthwashes on the number of S. mutans present in dental plaque around orthodontic brackets in fixed orthodontic patients.

This study was a randomized clinical trial. The total of 38 patients participate consisting of 12 patients in the fluoride group, 13 in the probiotic, and 12 in the placebo group. They were given mouthwashes to use twice a day for 2 weeks. Plaque sampling was performed using the 4‑pass technique in all three groups in two stages: before the intervention and after 2 weeks of using the mouthwash. The number of bacteria present in the dental plaque was then reported based on the number of colonies grown on agar medium. Data were analyzed using Kruskal–Wallis and Wilcoxon tests (α = 0.05).

Gender distribution, mean age, and protocol adherence were not significantly different among all three groups. After the intervention, the number of S. mutans present in the dental plaque followed an increasing manner in the placebo (P = 0.005) and probiotic (P = 0.158) groups and decreased in fluoride group (P = 0.025).

The L. plantarum probiotic mouthwash was ineffective in reduction of S. mutans in dental plaque. However, fluoride mouthwash is considerably effective against S. mutans and thus recommended.

 Topical fluoride products such as varnishes prevent dental caries by limiting demineralization and antibacterial properties. The structural and metabolic characteristics of cariogenic microorganisms are different from each other. Also, the formulation properties, concentration, and release behavior of fluoride vary in different varnishes.

 In this study, we investigated the antibacterial effects of three types of common fluoride varnishes against two cariogenic bacteria of Streptococcus mutans (S.M.) and Lactobacillus acidophilus (L.A.).

 In this in vitro study, antibacterial effects of MI varnish [containing calcium phosphopeptide-amorphous calcium phosphate (CPP-ACP)], Polimo (containing xylitol), and FluoroDose varnishes were evaluated using disc diffusion method via measuring the diameter of the inhibition zone. The antibiotics of erythromycin and ampicillin were used as the positive control of the test. Analysis of variance (ANOVA) and post hoc tests were applied to compare the mean of non-growth zone diameter in the studied groups. Data were analyzed by SPSS 16. The statistical significance level was determined as P-value < 0.05.

 The antibacterial effect of each varnish was optimal against both bacteria. In comparison, the mean diameter of the inhibition zone in MI varnish was significantly (P-value=0.019) higher than Polimo and FluoroDose brands on S.M.; however, this difference was not statistically significant for L.A. Furthermore, Polimo and FluoroDose varnishes showed similar antimicrobial effects against these bacteria.

 The use of these varnishes seems to be suitable for preventing tooth decay. MI varnish is preferable because of its higher antibacterial properties.

Antibiotic resistance of Klebsiella pneumoniae to quinolones is a serious concern in treatment of nosocomial infections. There are limited reports on the prevalence of plasmid-mediated quinolone resistance genes in K. pneumoniae clinical isolates from Iran. The aim of this study was to investigate the rate of resistance to fluoroquinolone antibiotics, and also the frequency of qnrA, qnrB, and qnrS genes among K. pneumoniae isolates collected from hospitalized patients in Sari, Iran.

In this descriptive cross-sectional study, bacterial isolates were identified by conventional methods and biochemical tests. Resistance to fluoroquinolone antibiotics was evaluated by disk diffusion method. After resistance assessment, amplification of qnrA, qnrB, and qnrS genes in isolates was performed by polymerase chain reaction (PCR).

We analyzed 90 isolates and the antibiotic resistance of fluoroquinolone included: nalidixic acid (55%), ciprofloxacin (36%), ofloxacin (31%), levofloxacin (29%), and norfloxacin (22%). The PCR showed that 47 (52%), 22 (25%), and 21(23%) isolates harbored qnrB, qnrA, and qnrS genes, respectively.

The outbreak of plasmid-mediated quinolone resistance (PMQR) leads to expand and increases bacterial resistance to fluoroquinolones. Therefore, continuous monitoring of antibiotic sensitivity patterns of K. pneumoniae strains to these agents is necessary.

Glycopeptide resistance genes can be transmitted to clinical strains from gram-positive environmental bacteria and the normal flora. The aim of this study was to evaluate the prevalence of vancomycin and teicoplanin-resistant Enterococcus faecalis and Enterococcus faecium isolates in hospital environment and fecal samples of healthy individuals.

Human stool and hospital environment samples were collected and inoculated on selective M-enterococcus agar medium. Then, E. faecalis and E. faecium were identified using phenotypic and molecular methods. Antibiotic susceptibility pattern of the isolates against teicoplanin and vancomycin was determined by micro-broth dilution method. Data were analyzed in SPSS applying Chi-square test.

From 145 isolates, E. faecalis and E. faecium were detected in 84 (54.93%) and 61 (42.07%) isolates, respectively. One (1.19%) E. faecalis isolate and 4 (6.56%) E. faecium isolates were resistant to vancomycin, while 4 (6.56%) E. faecium isolates were found to be resistant to teicoplanin. The minimum inhibitory concentrations of 50 (MIC50) and 90 (MIC90) for vancomycin and teicoplanin in E. faecalis and E. faecium were 4 and 16 μg/ml, respectively.

The MIC results of vancomycin and teicoplanin showed that most of enterococci isolates studied were sensitive to these two antibiotics. Therefore, their use should be closely monitored to prevent resistance.

Biogenic synthesis of silver nanoparticles (SNPs) have great attention of scientists, as it provide clean, biocompatible, non-toxic and inexpensive fabrication. In this study, Feijoa sellowiana leaf extract was used for synthesizing SNPs which reduces silver nitrate into silver zero-valent. SNPs were characterized by UV, FTIR, XRD, SEM-EDS and TEM analysis. They were also examined for their biological activities. The presence of biosynthesized SNPs was characterized by UV–visible spectroscopy and also crystal nature of SNPs identified with XRD analysis. FT-IR spectrum was used to confirm the presence of different functional groups in the biomolecules which act as a capping agent for the nanoparticles. The morphology of SNPs was explored using SEM and the presence of silver was confirmed by elemental analysis. The size of the nanoparticles was in the range of 20–50 nm determined by TEM. The green synthesized SNPs showed a good antibacterial activities against both gram-negative and gram-positive bacteria and also in resistant clinical isolated pathogens. Furthermore, the green synthesized SNPs showed reliable anticancer activity on the gastric adenocarcinoma (AGS) and breast (MCF-7) cancer cell lines with little effect on normal (HFF) cells. The in vitro antioxidant activity of SNPs showed a significant effect on scavenging of free radicals and iron chelating activity.

Nowadays, widespread use of automated teller machines (ATMs), has increased the possibility of contamination of hands due to contact with the surfaces of these devices. This study aimed to investigate the prevalence of bacterial contamination and antibiotic resistance pattern of the isolated bacteria from the keyboard of these devices in Sari, north of Iran.

In this descriptive-analytic study, the keyboards of 200 ATMs were sampled by sterile swab and transferred to the laboratory. The samples were inoculated in TSB medium and, after 24 hours of incubation at 37 ° C, were cultured on specific solid media and incubated. Then, the isolated bacteria were identified and their antibiotic resistance pattern was examined by disk agar diffusion method.

Bacterial contamination was observed in 97% of the samples. Klebsiella pneumoniae was the most frequent identified bacteria (36.08%), while Bacillus cereus was the least frequent bacteria (1.54%). K. pneumoniae showed a high resistance rate against Tetracycline (91.42%) and a low resistance rate towards Imipenem (2.85%).

Regular disinfection of ATM keyboards has a significant role in reducing and controlling bacterial contamination. Also, due to increased antibiotic resistance of isolated bacteria, it is possible to combat this problem by precise monitoring on the performance of antimicrobial stewardship programs.