Antibacterial Effects of Chitosan, Formocresol and CMCP as Pulpectomy Medicament on Enterococcus ‎faecalis, Staphylococcus aureus and Streptococcus ‎mutans

Introduction: During pulpectomy of primary teeth, cytotoxic medicaments such as formocresol or camphor mono-chlorophenol (CMCP) are used as medicaments. For the first time it is theorized that chitosan can substitute these traditional materials used in pulpectomy of infectious primary teeth. Methods and Materials: This preliminary in vitro study consisted of two separate phases (n=75), each of which assessed the antibacterial effects of chitosan versus formocresol and CMCP and positive/negative controls (n=15) on three bacteria types [Enterococcus ‎faecalis, Staphylococcus aureus, Streptococcus ‎mutans, (n=5 per subgroup)]. Phases 1 and 2 concerned respectively with 1- and 7-day effects of these materials. Bacteria were cultured and injected into sterilized canals and colonies were counted. Medicaments were applied and colonies were re-counted after 1 day of treatment (phase 1). Specimens were re-sterilized and re-randomized, and used for phase 2, in which the same procedures were performed for a 7-day period. Effects of agents on bacteria were analyzed statistically (Kruskal-Wallis α=0.05 and Mann-Whitney α=0.017). Results: Treatments reduced bacterial count either after 1 or 7 days (P=0.000). Their effects on different bacteria types were not significant either after 1 or 7 days (P>0.48). Antibacterial efficacies of treatments (indicated by colony reduction) were significantly different, after 7 days (P=0.045). Antibacterial efficacy of chitosan was similar to that of formocresol or CMCP, in both phases [either after 1 or 7 days of treatment (P>0.017). Formocresol and CMCP had similar efficacies in either phase (P>0.017). Conclusions: This preliminary study confirmed the appropriate antibacterial efficacy of chitosan as a medicament in pulpectomy of infectious primary teeth.Keywords: Antibacterial Agents; Camphor Mono-Chlorophenol; Chitosan; CMCP; Enterococcus ‎faecalis; Formocresol; Medicament; Pulpectomy; Staphylococcus aureus; Streptococcus ‎mutan

Identification of airborne fungi’s concentrations in indoor and outdoor air of municipal wastewater treatment plant

Background: Airborne fungi play an important role the quality of indoor and outdoor air. The aim of this study was to investigate the concentration of airborne fungi around different parts of the wastewater treatment plant (WWTP) in the west of Ahvaz and its relationship with some important meteorological parameters. Methods: This study was conducted on a WWTP in the west of Ahvaz during 4 months in both cold and warm seasons. Samples were collected from 2- and 10-m intervals of the grit chamber (GCh), primary sludge dewatering basin (PSDB), and aeration tank (AT), as well as 60 m upstream (US), downstream (DS), and administrative building (AB) of the WWTP. Bioaerosols were collected using passive sampling method. Temperature, humidity, wind speed, wind direction, and ultraviolet index (UV) were also measured at the time of sampling. Results: The total concentration of fungi was 46.1 ± 43 CFU/plate/h. The highest concentration of fungi (92.2 ± 28.12 CFU/plate/h) was found 2 m away from the GCh in the cold season and the lowest one (24.6 ± 6.67 CFU/plate/h) was found at the 10-m distance of the AT in the warm season. The dominant fungal genus included Cladosporium, Alternaria, Yeast, and Aspergillus, respectively. Also, there was a significant relationship between the degree of fungal contamination in different units, the US and DS of the WWTP, and there was a negative relationship between the release of fungi and UV. Conclusion: According to the results, grit chamber plays an important role in releasing airborne fungi. Also, airborne fungi were reduced with an increase in distance and UV. Keywords: Bioaerosols, Fungi, Meteorological parameters, Wastewater treatment plan

Distribution of genes encoding resistance to macrolides, lincosamides, and streptogramins among methicillin-resistant Staphylococcus aureus strains isolated from burn patients

The increasing resistance to macrolide, lincosamide, and streptogramin B agents among methicillin-resistant Staphylococcus aureus (MRSA) is a worldwide problem for the health community. This study aimed to investigate the prevalence of ermA, ermB, ermC, and msrA in MRSA strains isolated from burn patients in Ahvaz, southwest of Iran. A total of 76 isolates of S. aureus were collected from January to May 2017 from Taleghani Burn Hospital in Ahvaz. Among 76 S. aureus strains collected, 60 (78.9%) isolates were MRSA. The antimicrobial susceptibility testing for MRSA showed extreme high resistance rate to clarithromycin (100%) and azithromycin (100%), followed by erythromycin (98.3%). The PCR assay revealed that the frequency rates of msrA, ermA, and ermC genes were 23 (38.3%), 28 (46.7%), and 22 (36.7%), respectively. In addition, none of the MRSA isolates had the ermB gene. Because of the high prevalence of macrolide and lincosamide resistance found in MRSA isolates from infections of burn patients in Ahvaz, southwest of Iran, it is recommended that local periodic survey be performed for controlling the dissemination of antimicrobial resistance

Distribution of genes encoding resistance to aminoglycoside modifying enzymes in methicillin-resistant Staphylococcus aureus (MRSA) strains

Today Methicillin-Resistant Staphylococcus aureus (MRSA) have acquired multiple resistance to a wide range of antibiotics including aminoglycosides. So, this study was aimed to investigate the rate of aminoglycoside resistance and the frequency of aminoglycoside resistance mediated genes of aac(Ia)-2, aph(3)-IIIa and ant(4′)-Ia among MRSA strains. A total of 467 staphylococci isolates were collected from various clinical samples. S. aureus strains were identified by standard culture and identification criteria and investigating of presence of 16S rRNA and nuc genes. Cefoxitin disk diffusion, and oxacillin-salt agar screening methods were used to detect the MRSA strains with subsequent molecular identification for the presence of mecA gene. Antibiotic susceptibility of MRSA strains against aminoglycoside antibiotics was evaluated by using agar disk diffusion method. Multiplex PCR for the presence of aac(Ia)-2, aph(3)-IIIa and ant(4′)-Ia encoding genes for aminoglycosides were performed for MRSA strains. From total staphylococci tested isolates, 262 (56.1%) were identified as S. aureus, of which 161 (61.45%) were detected as MRSA and all comprised mecA gene. The resistance pattern of MRSA strains to aminoglycoside antibiotics were: gentamicin 136 (84.5%); amikacin 125 (77.6%); kanamycin 139 (86.3%); tobramycin 132 (82%); and neomycin 155 (96.3%). The frequency of aac(Ia)-2, aph(3)-IIIa, and ant(4′)-Ia genes among MRSA strains, were 64%, 42% and 11.8% respectively. In conclusion, as MRSA strains are of great concern in human infections, the results of present study could provide a useful resource for health sectors for choosing appropriate antibiotics for the effective treatment of infections due to MRSA strains

The frequency of class1 and 2 integrons in Pseudomonas aeruginosa strains isolated from burn patients in a burn center of Ahvaz, Iran.

Pseudomonas aeruginosa is an opportunistic pathogen with the ability to cause severe nosocomial infections and remains a major problem in burn patients. This organism shows a remarkable antimicrobial resistance and is often resistant to multiple antibiotics. Integron genes as mobile genetic elements are playing an important role in the spread of P. aeruginosa antibiotic resistance. This study was aimed to investigate the occurrence of class 1, and 2 integron genes (int1, int2), among P. aeruginosa strains isolated from patients with burn infections.In total 93 clinical isolates of P. aeruginosa were screened. The antimicrobial susceptibilities of 9 common antimicrobial agents were tested against the isolates using disk diffusion method. PCR amplification was performed on extracted DNAs for the detection of int1, and int2 genes using the set of specific primers.The majority of P. aeruginosa isolates were from wound infection (69.9%). In disk diffusion method, most isolates showed remarkable resistance to tested antibiotics with highest against gentamicin (94.62%) and ciprofloxacin (93.55%). PCR amplification revealed that 89(95.7%) of P. aeruginosa strains carried int1, but none of them harbored int2 genes. The distribution of int1 gene was highest in blood (100%), followed by wound isolates (95.38%).We demonstrated a high antimicrobial resistance among P. aeruginosa isolates in our setting. int1 was prevalent and seems to play an important role in multidrug resistance among the isolates. So, performance of antibiotic surveillance programs is necessary for choosing the appropriate therapy and management of infection control practices

Sequences of primers used for detection of integrase genes.

<p>Sequences of primers used for detection of integrase genes.</p

Antimicrobial resistance pattern of <i>P</i>. <i>aeruginosa</i> isolates.

<p>GM: Gentamicin, CIP: Ciprofloxacin, MEM: Meropenem, CRO: ceftriaxone; AK: Amikacin, PTZ: Pipracillin/Tazobactam, IMI: Imipenem, CAZ: ceftazidime; COL: Colistin.</p

Association between presence of integron and antibiotic resistance among 93 <i>P</i>. <i>aeruginosa</i> clinical isolates.

<p>Association between presence of integron and antibiotic resistance among 93 <i>P</i>. <i>aeruginosa</i> clinical isolates.</p

Prevalence of <i>P</i>. <i>aeruginosa</i> isolates in different hospital departments according to the type of clinical samples.

<p>Prevalence of <i>P</i>. <i>aeruginosa</i> isolates in different hospital departments according to the type of clinical samples.</p

Exploring the Important elements in the evaluation of the thesis supervisor of medical students: A qualitative research

Introduction: Introduction: The evaluation of the student dissertation supervisor is one of the important issues in improving the scientific and research level of students that has received less attention. Therefore, this study endeavored to identify the components of evaluation instruments of medical students' dissertation supervisors. Methods: This study was conducted with a qualitative approach and conventional content analysis method in the academic year 2021 in Ahvaz University of Medical Sciences. After reviewing the available articles and texts, the interview guide questions in a group discussion session with the participation of the research team; designed. Data were collected through structured interviews (electronically) and group discussion, and by purposeful sampling of stakeholders. The proposed Lundman and Graneheim steps were employed to analyze the data. Results: In this study, 22 faculty members and 10 students participated, which was collected from data analysis; 260 initial codes were obtained and after the final analysis in group discussion sessions, 50 codes were classified into three categories. Nine codes were obtained in the category of Supervisor Capacity, 15 codes in the category of General Ethics, and 26 codes in the category of Professional Ethics. Conclusion: In this study, 50 major factors were identified as elements and components of the evaluation instruments of the student's dissertation supervisor that can be used in the evaluation process of professors