Genetic diversity of Mycobacterium tuberculosis isolates from northwest of Iran during COVID-19 era.

Background: Tuberculosis (TB) is considered one of the most infectious diseases in the world. In this study, we intended to examine the epidemiology of tuberculosis by MIRU-VNTR to define the changes that occur in the transmission of tuberculosis in the region during the COVID-19 era. A total of 120 Mycobacterium tuberculosis isolates were collected from sputum samples of patients referred to East Azerbaijan Center TB from December 2020 to August 2021. Demographic information such as age, sex, place of birth, previous TB history, and relevant medical data was collected. The proportion method was performed for drug susceptibility testing, and the PCR-based MIRU-VNTR method was applied to identify molecular epidemiology relationships. Results: The isolates were collected from 78 male (65%) and 39 female (32.5%) Iranian patients and 3 (2.5%) Azerbaijani patients. Ninety-three distinct patterns were identified including 15 clustered patterns and 36 unique patterns. The largest cluster was composed of seven isolates. Furthermore, one cluster with 5 members, four clusters with 3 members, and nine clusters with 2 members. In MIRU-VNTR typing, 75 clusters belonged to the Tabriz region and just 3 to the Republic of Azerbaijan. All isolates were sensitive to rifampin, isoniazid, and ethambutol. Conclusions: Results of the current study showed COVID-19 pandemic had a direct effect on the transmission and diagnosis of tuberculosis. Less diagnosis and less clustering can indicate public controls and hygiene, and the use of masks had a direct effect on the transmission and diagnosis of tuberculosis. However, misidentification and less focus on other respiratory infections are expected during the pandemic. Studies on the co-infection of COVID-19 and tuberculosis and the role of mask and sanitization against TB are strongly recommended.

The comparison of calcium hydroxide, curcumin, and Aloe vera antibacterial effects on 6-week-old Enterococcus faecalis biofilm as an intracanal medicament: An in vitro study.

Background: This study aimed to compare the antibacterial effects of calcium hydroxide, curcumin, and Aloe vera as an intracanal medicament on 6-week-old Enterococcus faecalis biofilm. Materials and Methods: In this in vitro study, the solution containing E. faecalis ATCC® 29212™ was inserted into the canals of 72 single-rooted teeth to produce biofilm. The samples were divided into four groups, and the antibacterial agent as an intracanal drug was used for 1 week. Calcium hydroxide, curcumin, and A. vera were used as intracanal medicaments in three groups, respectively, and the fourth group was irrigated with normal saline. The collected debris was cultured by spread plate method for the bacterial count by colony count machine, and the number of bacteria in each sample per ml was reported in colony-forming unit per ml (CFU/ml). The data were analyzed using SPSS software. KruskalWallis and MannWhitney U-tests were used for comparison of CFU/ml between the study groups. P <0.05 was considered significant. Results: The mean CFU/ml in the groups of calcium hydroxide, curcumin, and A. vera were 749.44, 630.55, and 1529.16, respectively. Compared with the control group, curcumin, calcium hydroxide, and A. vera showed 99.5%, 99.41%, and 98.79% antimicrobial effects, respectively. All three groups were significantly effective than the control group (P = 0.023, P = 0.023, and P = 0.024, respectively) but were not significantly different from each other (P = 0.057). Conclusion: All three groups showed significant antibacterial activity compared to the control group, curcumin had the most significant effect, followed by calcium hydroxide and A. vera. Therefore, herbal materials can be considered safe alternatives to synthetic medicaments for intracanal usage.

Detection of carbapenem-resistant Enterobacteriaceae by chromogenic screening media.

Enterobacteriaceae are a part of the human intestinal flora easily spread by hand carriage, water and food. Treatment of infections due to Enterobacteriaceae is difficult mainly in countries with a low socioeconomic state. Carbapenems are considered as a last-resort antibiotic for the treatment of infections due to multidrug-resistant Enterobacteriaceae. Carbapenem-resistant Enterobacteriaceae (CRE) presents a major threat to public health and are rapidly disseminating globally. The most important resistance mechanism of Enterobacteriaceae to carbapenems is carbapenemase production. The treatment options for CRE are limited; attention is focused here on the rapid detection of CRE. Laboratory surveillance of cultures and screening of patients are essential and desirable in areas where these strains are endemic. Culture-based methods such as chromogenic media are used for the initial detection of these strains. These media offer a sensitive, convenient, and low-cost way of identifying CRE species. This article provides an overview of the current state of culture-based chromogenic screening media for the detection of CRE.

Frequency of bap and cpaA virulence genes in drug resistant clinical isolates of Acinetobacter baumannii and their role in biofilm formation.

OBJECTIVES: Acinetobacter baumannii has a high propensity to form biofilm and frequently causes medical device-related infections with multiple-drug-resistance in hospitals. The aim of this work is to study antimicrobial resistance and the role of bap and cpaA genes in biofilm formation by A. baumannii to understand how this pathogen persists in the hospital environment. MATERIALS AND METHODS: The antibiotic resistance profile and invitro biofilm-forming ability of one hundred clinical isolates of A. baumannii was evaluated by disc diffusion and crystal-violet staining methods, respectively. Isolates were tested for the presence of bap and cpaA genes. RESULTS: The isolates were highly resistant to cefepime, third-generation cephalosporins, ciprofloxacin, cotrimoxazole, aminoglycosides and carbapenems. Moreover, four isolates were resistant to colistin. Quantification of biofilm showed that 43% of the isolates were strong biofilm-producer. Furthermore, 32% of the isolates exhibited moderate biofilm-formation and showed initial binding activity. Frequency of bap and cpaA were determined 92% and 36%, respectively. CONCLUSION: There was strong association between the presence of bap gene and biofilm formation by A. baumannii isolates (P=0.003). In addition, multidrug resistant isolates produced stronger biofilm than other isolates (P=0.0001). These results indicate importance of biofilm in resistance of isolates and effect of presence of bap gene in biofilm formation by A. baumannii strains.

Antibacterial effect of different concentrations of sodium hypochlorite on Enterococcus faecalis biofilms in root canals.

Background. The aim of this study was to evaluate the effectiveness of different concentrations of sodium hypochlorite (NaOCl) solution in reducing bacterial growth in Enterococcus faecalis biofilms in root canals. Methods. The root canals of maxillary central incisors of 104 subjects underwent chemomechanical debridement. In order to remove the smear layer, 5.25% sodium hypochlorite solution was used for 3 minutes in the root canals. Then, the samples were immersed in 1 mL of 17% EDTA for 3 minutes. Finally, the root canals were irrigated with phosphate-buffered saline (PBS) solution. After removing the smear layer, the samples were sterilized. Then E. faecalis biofilms formed within the root canals at 4-, 6-, and 10-week intervals were evaluated. Each group was divided into 4 subgroups in terms of the antibacterial treatment: group 1: 1% NaOCl solution; group 2: 2.5% NaOCl solution; group 3: 5.25% NaOCl solution; and group 4: PBS solution. After preparation of root canal filings, the counts of live bacteria were calculated through the classic method of counting, i.e. colony forming units (CFU), followed by the analysis of data. Results. In groups 2 and 3, there was no bacterial growth due to complete removal of E. faecalis biofilms (P<0001), while the bacterial counts in group 1 at 4-, 6- and 10-week intervals decreased compared to the control group. Conclusion. The bacterial cells in mature and old biofilms have higher resistance to 1% NaOCl solution compared to the young biofilms. However, the 2.5% and 5.25% NaOCl solutions caused complete inhibition of the growth of E. faecalis biofilm in all the stages of development.

Antimicrobial efficacy of photodynamic therapy and sodium hypochlorite on monoculture biofilms of Enterococcus faecalis at different stages of development.

BACKGROUND AND OBJECTIVE: As the Enterococcus faecalis biofilm ages, it is likely that bacteria in mature and old biofilms will become more resistant to commonly used antibacterial irrigants. Photodynamic therapy (PDT) has been used to kill resistant bacteria organized in a biofilm. This study aimed to investigate the antimicrobial effectiveness of 1% sodium hypochlorite (NaOCl), 2.5% NaOCl, and PDT on E. faecalis biofilm at different stages of development. METHODS: In this study 4-, 6-, and 8-week-old E. faecalis biofilms were subjected to one of the following approaches: phosphate-buffered saline solution (PBS), PDT, or 1% and 2.5% NaOCl. Dentin chip suspensions were used for colony forming units (CFU) counting to estimate remaining E. faecalis counts. RESULTS: PDT and 2.5% NaOCl completely eliminated E. faecalis biofilms in three stages of biofilm development, whereas 1% NaOCl resulted in 81.88%, 85.73%, and 78.62% reductions of bacterial counts in 4-, 6-, and 8-week-old biofilms, respectively, which was significantly more than PBS. CONCLUSIONS: The bacteria in mature and old biofilms were more resistant to 1% NaOCl than were the bacteria in young biofilms. Overall survival and residual bacteria increase with biofilm aging. PDT and the 2.5% NaOCl solution were equally efficient in completely eliminating E. faecalis biofilms at all three stages.