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Introduction: Given that hospital air is one of the important environmental sources for transmission of microorganisms, the importance of airborne transmission in the epidemiology of hospital-acquired infections (HAIs) has gained attention in the past two decades. Therefore, the present study aims to determine the concentration of bacteria in association with airborne particulate matter (PM) in the outdoor and indoor air of two hospital wards. Materials and methods: The GRIMM 1.109 dust monitor and the Andersen one-stage viable impactor were used for particle counting and bioaerosol sampling, respectively. Results: The average levels of airborne bacteria sampled from outdoor air were 33 colony-forming units (CFU/m3), and in the air samples of medical and infectious disease wards, they were 76 and 85 CFU/m3, respectively. Staphylococcus spp. and Acinetobacter spp. were the most prevalent bacteria in the samples. Statistical analysis showed a significant association between PM2.5, and PM10 particle mass concentrations and airborne bacteria concentrations in indoor air samples (P-value < 0.05). Conclusion: Some bacterial agents of HAIs existed in hospital air and may be problematic for immunocompromised patients. Higher levels of bacteria in indoor air compared to outdoor air may indicate that the bacteria were of indoor origin, such as the presence and activities of people. Moreover, the results showed that particle counting may be a useful tool for airborne bacteria monitoring.

Objectives: Air pollutants in dentistry offices may cause problems for the health of staff and patients. Accordingly, the present study was performed to the assessment of bacterial bioaerosols and particulate matter (PM) characteristics in the indoor air of dentistry clinics.Methods: The sampling points were restoration, endodontics, and prosthesis wards. The PM specimens were taken using Grimm Dust Monitor and the microbial specimens were taken using QuickTake 30.Results: The maximum and minimum PM10 concentration across the different measure wards occurred as 70.31 and 30.32 μg/m3 in the Ketabchi Clinic restoration and its endodontics ward, respectively. The total number of bioaerosols was 2079. Gram‑positive Staphylococcus spp.(872), Gram‑positive Micrococcus spp.(706), and Gram‑negative Bacillus spp.(501) were present in the indoor air. The results showed a significant relationship for PM1 and PM2.5 in each sampling site.Conclusions: The low PM and bacterial bioaerosols contamination can be due to the coincidence with coronavirus pandemic, as during this period, health and hygienic protocols have been strictly observed.

Introduction: Maintaining hospital air quality is very important, especially in intensive care units (ICUs), where patients undergo invasive procedures. Therefore, the present study was conducted with the aim of determining the relationship between particulate matters (PMs) and bioaerosols in pediatric ICU (PICU), neonatal ICU (NICU), and ICU open heart (ICU OH) of Shahid Beheshti Hospital in Kashan. Materials and Methods: This cross-sectional study was conducted for six consecutive months, i.e., autumn and winter of 2021. PM samples were taken using a Grimm Dust Monitor and microbial samples were taken using a Quick Take 30 sampler. Kolmogorov-Smirnov test was used for analysis and then ANOVA and LSD were used for further tests. Results: The maximum and minimum PM10 concentrations in the PICU and ICU OH were 59.19 and 9.71 μg/m3, respectively; and the maximum and minimum PM2.5 concentrations were 20.23 μg/m3 in the NICU and 4.69 μg/m3 in PICU. The mean PM concentration and the number of bacterial and fungal colonies were consistent with the WHO and EPA guidelines. Gram-positive Staphylococcus were the most abundant bacteria (90.96%). The most abundant fungi were Aspergillus (54.23%), Penicillium (15.64%), and Cladosperium (12.17%) species. There was also no significant relationship between PMs and bioaerosols. Conclusion: The mean concentrations of PMs and bioaerosols match with the guidelines, which can be attributed to more observance of health protocols and restrictions on the movement of people into ICUs due to the COVID-19 outbreak.

The emergence, spread, and persistence of multidrug-resistant (MDR) bacteria have become a public health threat. Therefore, it is urgent to investigate novel antimicrobial materials without antibacterial resistance. In this regard, Copper/graphitic carbon nitride nanocomposites (Cu/g-C3N4 NCs) with different loading amounts of Cu nanoparticles (NPs) have been successfully prepared via the co-precipitation-sonication approach. The purity of the nanostructures was verified by the X-ray diffraction (XRD) pattern. The antibacterial activity of Cu/g-C3N4 NCs versus tested bacteria were determined by the microdilution technique. Inhibition of biofilm formation was also evaluated using the microtiter plate method. In addition, the ability of Cu/g-C3N4 NCs to the expression level of the icaA gene was assessed by the Real-Time PCR technique. Our results showed that the doping of graphitic carbon nitride with Cu-NPs can improve the antibacterial activity of g-C3N4. So, sample 4 (Cu:g-C3N4 1;1), with higher Cu content, had the highest antibacterial activity toward tested bacteria. The result also showed that sample 4 recorded the largest inhibition zone diameters against tested bacteria, including Staphylococcus aureus (29 mm) and Pseudomonas aeruginosa (16 mm). In addition, Cu/g-C3N4 NCs exhibited a 65% reduction in biofilm formation for Staphylococcus aureus. Moreover, icaA gene was down-regulated after treatment with Cu/g-C3N4 NCs. In conclusion, our study showed that extract Cu/g-C3N4 NCs can use as a promising anti-biofilm agent against biofilm–producing bacteria.

Abstract Background Meningitis is considered a life-threatening infection with high mortality all over the world. Hemophilus influenzae (H. influenzae) and Streptococcus pneumoniae (S. pneumoniae) are regarded as the two most common infectious agents causing bacterial meningitis. This study aimed to identify H. influenzae and S. pneumoniae serotypes in blood and cerebrospinal fluid (CSF) of pediatric patients with meningitis, using polymerase chain reaction (PCR). Methods This multi-center cross-sectional study included 284 children with suspected meningitis referred to 4 target hospitals. Overall, 412 samples (128 blood and 284 CSF samples) were obtained from the patients from November 14, 2016 to November 15, 2017. The extracted DNA was examined using multiplex real time PCR to screen for S. pneumoniae and H. influenzae. S. pneumoniae serotyping was also done by multiplex PCR. Results Out of 284 CSF specimens, 22 were positive for ply S. pneumoniae. Of 20 DNA samples meeting the Quality Control (QC) standards for serotyping, 7 (35%), 6 (30%), 2 (10%), 2 (10%), 2 (10%), 1 (5%), 1 (5%), 1 (5%), 1 (5%) and 1 (5%) were positive for serotypes 3, 11A, 6A, 14, 7C, 23F, 23B, 19A, and 19F and 5, respectively. Overall, nine samples were positive for two serotypes, of whom 3 and 11A were the most common from Tehran province. Of note, one of these CSF samples showed a new co-infection with serotypes 7C and 14. Also, 6 samples (30%) were positive for H. influenzae detected by bexA primer. None of the blood samples were positive for S. pneumoniae or H. influenzae. Conclusion Co-infection with S. pneumoniae serotypes can occur in bacterial meningitis and it might be missed if all serotypes are not evaluated in CSF specimens.

Background and Objectives: In the past few years, application of new antimicrobial e.g. nanoparticles (NPs) to treat infection caused by drug-resistant bacteria has increased. This study aimed to determine antimicrobial property of silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) in combination with linezolid on Enterococcus biofilm. Materials and Methods: A total of forty-eight isolates of Enterococcus spp. were collected and confirmed by PCR method. The synthesis of biocompatible AgNPs was performed, then analyzed by Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy. We carried out minimum inhibitory concentration (MIC) and biofilm forming capacity of AgNPs and AuNPs with linezolid. Results: Twenty-two E. faecium isolates and twenty- six E. faecalis investigated in this study. Strong biofilm formation was seen in 12 (25%) of isolates, and others isolates (75%) formed moderate biofilm. AgNPs and Au-NPs size were 26 nm and 20 nm respectively. The MIC of AgNPs was 23.2 μg/ml, and AuNPs were 92.1 μg/ml and the lowest MIC was obtained 2 μg/ml in linezolid. Biofilm formation inhibitory activity by AuNPs + Linezolide and AgNPs + Linezolide 70 to 80 percent increased in average. Conclusion: The antibiofilm activity of AgNPs and AuNPs increased when both agents were used in combination with linezolid in comparison with each agent alone.

Background: The health of patients with weakened immune systems is endangered by presenting of bacteria and fungi in the internal units of hospital as well as development of nosocomial infections in them. The current article aimed to investigate the bacterial and fungal contamination degree in internal units and outdoor of the hospital in which some points are mainly considered such as the nosocomial infections and the discussion of improving the quality of hospital spaces and providing appropriate conditions to maintain the health of patients. Materials and Methods: This study is a cross sectional study conducted in Kashan Beheshti hospital in 2018. Air sampling is done by direct bacterial sampler (Quick Take 30) along with identification of type and the number of fungi and bacterial colonies including 180 samples from internal units and outdoor spaces. Data was analyzed statistically by SPSS 22, EXCELL and BONFERRONI test. Results: The obtained results from 180 samples showed that bacterial and fungal contamination among 180 samples was 97% and 47.8%, respectively. Also, the most bacterial and fungal contamination presented in medical units and outdoors, respectively. Conclusion: The results revealed that the micro-organism concentration in internal units is more than in outdoors that results can be related with the presence of the patients, air conditioning and inappropriate cleaning. For this reason, improving sanitation standards and setting the appropriate air-conditioning are suggested in internal units of the hospital.

Abstract Objective Streptococcus agalactiae is an important pathogen in neonates and pregnant women. Neonatal invasive infections due to S. agalactiae are life-threatening and preventive strategies for this challenge of human have become a concern. The aim of the present study was to determine the prevalence of rectovaginal colonization, related risk factors and antibiotic resistance pattern of S. agalactiae among pregnant women in Iran. Methods The present study was performed on 240 pregnant women. Vaginal and rectal swabs were obtained from all of the women and then were transferred to the laboratory. The isolation and identification of S. agalactiae was performed by standard microbiological tests and polymerase chain reaction (PCR) assay. The antimicrobial susceptibility patterns of the isolates were determined by the Kirby-Bauer disk diffusion. Polymerase chain reaction was used to detect ermB and mefA genes in erythromycin-nonsusceptible isolates. Results Out of 240 pregnant women, 16 cases (6.7%) were colonized by S. agalactiae. There is no significant association between demographic-obstetric factors and maternal S. agalactiae colonization in the pregnant women. Linezolid, vancomycin and ampicillin were the most effective antibiotics against S. agalactiae. The ermB gene was present in 6 (35.29%) S. agalactiae isolates. However, the mefA gene was not detected in any of the isolates. Conclusion Given the relatively significant prevalence of S. agalactiae colonization in the pregnant women in the present study and the risk of serious neonatal infections, the screening of pregnant mothers for the bacteria seems necessary. Our findings highlight the importance of appropriate antibiotic prophylaxis during pregnancy for the prevention of early onset S. agalactiae-neonatal infection and comorbidity.

Aims:Staphylococcus aureus is considered a major cause of food poisoning in the world. We aimed to investigate the prevalence of S. aureus isolated from hamburgers in Kashan city. Materials and Methods: In this study, 71 hamburger samples were collected from supermarkets in Kashan from March to July 2017. The samples were examined after dilution in the Baird–Parker Agar Base medium of inoculation for the bacterial growth of S. aureus. Gram staining, catalase tests, mannitol fermentation, coagulase, DNase, and sensitivity to novobiocin were used to detect the bacteria. Results: The collected hamburgers were about eight types of products. Of the total samples, 15 (21.13%) were Gram-positive bacteria contaminated, including seven cocci and eight bacilli. Seven samples (9.86%) of hamburgers were contaminated with S. aureus. The average counts of S. aureus in positive samples were 1.94 × 103 colony-forming unit (CFU)/g. Conclusion: The outbreak of S. aureus isolates in meat products, particularly hamburger, is of serious threat to public health. To prevent the outbreak of this pathogen in hamburgers, permanent control and monitoring should be performed in food industries.

Introduction: Streptococcus pneumoniae is one of the major pathogens responsible for respiratory tract infections, meningitis, and bacteremia. In most countries around the world, an increase in the emergence of macrolide-resistant S. pneumoniae isolates has become a serious problem. Therefore, this study was conducted to investigate the association of erythromycin resistance with the mefA and ermB genes among clinical isolates of S. pneumoniae in Tehran City (Tehran Province, Iran). Materials and Methods: In this cross-sectional study, 62 erythromycin-resistant S. pneumoniae (ERSP) isolates were obtained from patients in four hospitals in Tehran city during 2013-2015. The macrolide resistance genes mefA and ermB were detected in ERSP isolates using polymerase chain reaction (PCR) assays. Furthermore, the copy number and expression level of the mefA gene were determined by real-time PCR. Results: In the present study, the overall resistance to erythromycin in S. pneumoniae isolates was 84.93% (62 isolates out of 73). Either mefA or ermB was identified in 10 (16.13%) and 36 (58.06%) ERSP isolates, respectively, and 7 (11.29%) ERSP isolates harbored both genes. Comparison of the mean relative expression of the mefA gene in ERSP isolates with different erythromycin minimal inhibitory concentration (MIC) values indicated that the expression level was increased approximately twofold for each doubling of the MIC value. Conclusion: Our findings highlighted the dominance of ribosomal methylation encoded by ermB as the most common mechanism of macrolide resistance in clinical S. pneumoniae isolates from Iran. Furthermore, in the present study, the expression levels of the mefA gene showed a significant increase in the ERSP isolates with higher erythromycin MIC values.

Introduction: In recent years, the use of nanoparticles (NPs) to eliminate pathogenic bacteria is increasing. The development of biological and nontoxic methods for synthesizing NPs is an important topic in nanotechnology to allow the use of these NPs for health and medical purposes. This study aimed to synthesize silver NPs (AgNPs) using bacterial culture medium and then evaluated the antibacterial activity of these NPs against Acinetobacter baumannii. Materials and Methods: The synthesis of biocompatible AgNPs was performed by brain heart infusion culture medium. Synthesized NPs were observed using ultraviolet-visible spectroscopy and were characterized by Fourier transform infrared spectroscopy (FTIR). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were conducted to examine the morphology of AgNPs. The minimum inhibitory concentration (MIC) was determined to measure the antibacterial effect of AgNPs. Finally, antibiofilm activities of the synthesized AgNPs were assessed. Results: Ultraviolet-visible spectroscopy showed that the highest absorption of the synthesized NPs was at 420 nm. Results of SEM and TEM revealed that the morphology of particles was spherical and irregular, and their mean diameter was 26 nm. In addition, FTIR results confirmed that the reducing, capping, and stabilizing agents of NPs were proteins. Minimum inhibitory concentration of AgNPs ranged from 1.56 to 12.5 µg/ml, and at 2 MIC concentration, the biofilm formation inhibitory activity of NPS increased. Conclusion: Brain heart infusion medium was successfully applied for synthesizing stable AgNPs, and these NPs showed good antibacterial and antibiofilm activity against A. baumannii.

Background and Aim: In the new era of n E-learning technology, the models of microbiology education are changing. To improve the quality of learning microbiology, presenting multimedia clips in the classroom is a matter of debate among educators. This study aimed to evaluate the effect of presenting clips on academic learning and satisfaction of learners in the microbiology course. Materials and Methods: In this quasi-experimental study, 69 B.Sc. students of health in Birjand University of Medical Sciences who took part in the microbiology course were studied in two groups. In the case group, teaching was based on a combination of lectures by presenting PowerPoint slides and also showing clips while in the control group, the teaching was only based on PowerPoint presentation. In the middle and at the end of the semester, the rate of satisfaction and academic learning was compared between the two groups. The data were collected by the researcher-made questioner for student satisfaction and by scientific exams for academic learning. Results: The results showed that the amount of learning in the case group (based on a combination of lectures by presenting PowerPoint slides and also showing clips) was significantly higher than the control group (lectures by presenting PowerPoint slides). The average satisfaction score of students for PowerPoint slides-based teaching and combined teaching was 25.32 ± 4.31 and 25.48 ± 3. 21 respectively, that this difference was not statistically significant (P=0.85). Conclusion: Presenting multimedia clips to students during microbiology courses is a powerful tool for learning. Development of clips as a main part of learning content in microbiology courses is suggested.

Background: Non-tuberculous mycobacteria (NTM) are defined as mycobacteria other than Mycobacterium tuberculosis (MTB), which do not cause tuberculosis or leprosy. Early and precise diagnosis of NTM is particularly important for the correct epidemiological control and specific treatments. The aim of this study was to identify the mycobacterium species isolated from patients referred to hospitals in Tehran using the high-performance liquid chromatography (HPLC) method. Materials and Methods: In this cross-sectional descriptive study, a collection of isolates (n=20) was obtained from clinical specimens submitted to the Masoud Laboratory in Tehran, Iran, during 2014-2015. The strains were isolated from sputum, urine, blood, and various sterile body fluid specimens. Chromatography was conducted at a flow rate with a curvilinear gradient of methanol and methylene chloride, beginning at 98% methanol containing 2% methylene chloride and ending at 35% methanol contained in 65% methylene chloride. Results: From a total of 20 clinical isolates, 8 isolates (40%) were identified as Mycobacterium abscessus, 6 isolates (30%) M. tuberculosis, 3 isolates (15%) M. intracellulare and 3 isolates (15%) M. fortuitum. Conclusion: For the proper treatment, rapid differentiation between MTB and NTM should be performed in persons who are diagnosed with or are suspected of having infectious TB disease. So, the HPLC method can be suggested as a cost-effective, specific and reliable method for rapid identification of MTB and differentiation of NTM strain from positive cultures isolated from clinical specimens.

Background: Conjunctivitis is a very common ocular disease, which can be caused by a wide variety of microorganisms. This study was aimed to assess the bacterial etiology and antibiotic susceptibility of conjunctivitis patients' isolates from Central Iran. Materials and Methods: This study was performed in 180 patients referred to the Department of Ophthalmology in Kashan University with symptoms of conjunctivitis from July 2017 to December 2017. To detect of different bacteria, Gram staining, morphological characterization, pigment production, biochemical characteristics, coagulase test, optochin and PYR tests, oxidase test, and culture on specific media were used. Antibiotic susceptibility of the bacteria isolated was done using the Kirby–Bauer method. Methicillin resistance in staphylococci isolated from the patients was identified using polymerase chain reaction technique. Results: Of the 195 bacteria isolated, about 81.5% were Staphylococcus epidermidis and Staphylococcus aureus and the remaining 19.5% included other species. In the present study, Pseudomonas aeruginosa was most resistant to ampicillin. In the case of S. epidermidis and S. aureus, the highest resistance was observed against erythromycin and the least resistance was against rifampicin and linezolid. Conclusion: In this study, S. aureus and S. epidermidis are the most common causes of conjunctivitis in all age groups, however, this condition decreases with age and is also influenced by other factors such as season and weather conditions. The results of this study can be helpful in planning more prudent treatment strategies for patients with conjunctivitis in Kashan.

Background: The aim of this study was to investigate the antibiotic susceptibility pattern as well as the phenotypic and genotypic biofilm formation ability of Staphylococcus aureus isolates from patients with urinary tract infection (UTI). Methods: A total of 39 isolates of S. aureus were collected from patients with UTI. The antibiotic susceptibility patterns of the isolates were determined by the Kirby-Bauer disk-diffusion. We used the Modified Congo red agar (MCRA) and Microtiter plate methods to assess the ability of biofilm formation. All isolates were examined for determination of biofilm related genes, icaA, fnbA, clfA and bap using PCR method. Results: Linezolid, quinupristin/dalfopristin and chloramphenicol were the most effective agents against S. aureus isolates. Overall, 69.2% of S. aureus isolates were biofilm producers. Resistance to four antibiotics such as nitrofurantoin (71.4% vs. 28.6%, P=0.001), tetracycline (57.7% vs. 42.3%, P=0.028), erythromycin and ciprofloxacin (56% vs. 44%, P=0.017) was higher among biofilm producers than non-biofilm producers. The icaA, fnbA and clfA genes were present in all S. aureus isolates. However, bap gene was not detected in any of the isolates. Conclusion: Our findings reinforce the role of biofilm formation in resistance to antimicrobial agents. Trimethoprim-sulfamethoxazole and doxycycline may be used as an effective treatment for UTI caused by biofilm producers S. aureus. Our results suggest that biofilm formation is not dependent to just icaA, fnbA, clfA and bap genes harbor in S. aureus strains.

Background and Objectives: To investigate coagulase gene polymorphisms of MRSA and MSSA isolates from Shiraz teaching hospitals from 2011 to 2012. Materials and Methods: A total of 302 isolates of Staphylococcus aureus were collected from clinical specimens in three major teaching hospitals and confirmed on the basis of morphological characteristics and biochemical tests. The isolates were subjected to molecular typing on the basis of coagulase enzyme gene polymorphism by PCR-RFLP. Results: There were 27 and 28 different RFLP patterns for AluI and HaeIII restriction enzymes respectively. This study showed that the discriminatory power of coagulase gene typing by Hae III enzyme was more than that of Alu I enzyme. Conclusion: PCR-RFLP method is rapid, reproducible, simple and efficient for typing Staphylococcus aureus isolated from clinical specimens. This study showed that Hae III discriminatory power is better than Alu I for typing Staphylococcus aureus isolates.

Background and Aim: Despite the anti-cancer and antimicrobial properties of licorice extract and lavender essential oil, some factors, such as low bioavailability and biodegradable, limit their therapeutic use. Using nanoparticles is a method to overcome these restrictions. This study aimed to investigate the anti-proliferative effects of nanoemulsion containing licorice extract and lavender essential oil on cancer cells; we also evaluated its antimicrobial properties in vitro. Methods & Materials: In this experimental study, nanoemulsions, containing licorice extract and lavender essential oil were developed by the spontaneous emulsion method. The anti-proliferative effect of nanoemulsion was investigated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) colorimetric method on two cell lines HepG2 and SK-MEL-3. To measure the antimicrobial effect of 4 standard strains of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus epidermidis, and Minimum Inhibitory Concentration (MIC) method was used. Ethical Considerations: This study was approved by the Ethics Committee of Kashan University of Medical Sciences (Code: IR.KAUMS.MEDNT.REC.1396.106). Results: The results of MTT test on HepG2 cells indicated that the concentrations of 630, 1250, and 2500 μg/mL nanoemulsions caused toxicity to the cell and led to the death of >50% of the cells (IC50=401μg/mL; P50% of the cells (IC50 = 82 μg/mL; P

Background/Objectives: The genus Mycobacterium contains over 140 species comprises pathogenic and nonpathogenic strains. Nontuberculous mycobacteria (NTM) causing clinical disease have become increasingly common and more diverse. Widespread features of NTM infection can make the diagnosis difficult. Precise species-level detection can aid in distinguishing environmental contamination from actual infection and, furthermore, can assist in making a choice of antimicrobial therapy. Materials and methods: Mycolic acids extracted from saponified mycobacterial cells were examined by high performance liquid chromatography (HPLC) in addition to phenotypic tests for the identification of 20 clinical isolates of mycobacteria at Masoud Laboratory during 2014–2015. Results: Mycobacterium abscessus (8 isolates), Mycobacterium tuberculosis (6 isolates), Mycobacterium intracellulare (3 isolates) and Mycobacterium fortuitum (3 isolates) were identified in these isolates. The phenotypic tests also confirmed the identity of the clinical isolates. Conclusion: Our results showed that HPLC is a more reliable, rapid, simple, easy-to-perform, cost-effective, and specific identification method compared with other identification procedures like phenotypic tests.