International Journal of Molecular and Clinical Microbiology
Volume:11 Issue: 1, Winter and Spring 2021

Burn is one of the most traumatic injuries and life-threatening states which is a global public health problem, accounting for an estimated 180 000 deaths annually. In burn trauma patients, intubation and ventilator-associated pneumonia (VAP) is a major threat. Added to other complications this may be responsible for the higher morbimortality of burn patients. In this one-year cross-sectional study (September 2018 to September 2019), a total of 70 patients hospitalized in the burn ICU ward were sampled according to the study criteria. Cases were hospitalized in Amir-al-Momenin burn hospital, affiliated with Shiraz University of Medical Sciences. Tracheal samples were evaluated for bacterial infection with standard microbiological techniques. In the following process, an antibacterial susceptibility test was performed for confirmed isolates with the Kirby-Bauer method and recommended antibiotics by the Clinical and Laboratory Standards Institute. According to the results of the study, a total of 21 (30%) positive growth samples were detected. The age range of patients was estimated at 1–60 years old with the mean age 29.61±21.56 years. The lowest resistance rate was seen in Pseudomonas aeruginosa and Staphylococcus aureus isolates against gentamycin. Based on the results, it was seen that all Escherichia coli isolates were resistant against all of the examined antibiotics. Appropriate infection control policies and knowing the antimicrobial pattern in burn patients especially in intensive care units may help to provide the best treatment for burn patients and save their life.

Among lactic acid bacteria (LABs), Lactococcus lactis has been much concerned because of its acceptable stability and bacteriocin (nisin) production. This study was aimed to investigate the antibacterial effects of bacteriocin produced by Lactococcus lactis isolated from native dairy products against some foodborne pathogenic bacteria and to optimize its production conditions. First, 15 strains of Lactococcus lactis were isolated from sheep and goat milk samples in M17 culture medium and identified by biochemical and molecular methods. Then, the optimal conditions for bacteriocin production by Lactococcus lactis were determined using Taguchi statistical method in terms of pH, temperature and production time. Evaluation of the antimicrobial activity of bacteriocin produced against standard strains of foodborne pathogens was evaluated by well diffusion method. Cell-free supernatants were obtained from Lactococcus lactis I8 from goat milk showed antimicrobial activity against Shigella flexneri, Salmonella typhimurium, and Staphylococcus aureus strains; While Escherichia coli showed resistance to the bacteriocin. Optimal bacteriocin production by Lactococcus lactis was done at pH = 7, temperature of 26 °C and 22 h incubation period. The high antibacterial activity of this bacteriocin against putative pathogens such as Salmonella typhimurium and Shigella flexneri would make it a good candidate as a probiotic strain to be used for treatment of infections caused by these bacteria, and also the application possibility of the produced bacteriocin as a suitable food preservative is proposed.

Salmonella, as one of the most important zoonotic foodborne pathogens, is a major global threat to the health of human communities and animals and its impact is economically significant in the world. This study aimed to investigate Salmonella infection and bacterial susceptibility test on possible isolates in some broiler turkey flocks in Iran. For this purpose, diagnostic samples were collected at slaughterhouse from 15 different broiler turkey flocks at the ages of 16 to 18 weeks, from different geographical regions of the country. In this regard, 15 complete intestinal samples were taken from each flock and a total of 225 intestinal samples were collected and sent to the laboratory for culture, isolation and identification of Salmonella. From every 5 intestinal samples different parts were pooled and cultured in selenite F medium and transferred to Salmonella Shigella agar (SS) and MacConkey agar (MAC) media after 24 hours, then suspected Salmonella colonies were transferred to the differential medias. Salmonella positive colonies were used for serogroup identification and all isolates were identified being from D serogroup. The PCR were performed for identification of Salmonella spp and 7 Salmonella isolates were confirmed. Then the PCR with specific primers for the identification of Salmonella Enteritidis was performed on 5 isolates and 4 isolates were identified as Salmonella Enteritidis. In addition, antimicrobial susceptibility test was performed on 7 isolates and it was found that all of them were completely sensitive to Fosfomycin and the highest resistance was observed in Colistin.

Cellulolytic bacteria can be found in soil and ruminal wastes. The present study was conducted to isolate and identify cellulose degrading bacteria from forest soil and bovine waste and their screening for potential antifungal activity. The cellulolytic bacteria were isolated from the samples by serial dilution method on modified Czapeck (CMC) agar and following Congo red assay. Seventeen isolates were selected on the basis of cellulolytic activity through Congo red assay. The antifungal activity of these isolates was also determined against different phytopathogenic fungi including Alternaria, Cladosporium, Verticillium, Fusarium, Mucor and Rhizopus. The isolates were identified using standard biochemical tests according to Bergey’s manual. Among the 17 isolates, 11 to Bacillus spp., 2 to Pseudomonas spp., 1 to Citrobacter spp., 3 to Staphylococcus spp. belonged. The antifungal activity against the target phytopathogens was shown by the 2 isolates of Bacillus. Isolate Bacillus spp. R7 from the bovine waste showed high activity against Alternaria by giving a zone of inhibition of 16 mm while isolate R1 from the forest soil showed antifungal activity against Fusarium by giving a clear zone of 13 mm. Based on the results of sequencing isolates R7 and R1 were most similar (more than 90% identity) to Bacillus licheniformis and Bacillus Subtilis strains, respectively. The results of the present study shows that cellulolytic bacteria are promising for biocontrol of phythopathogens and it is possible to use them as an effective strategy to manage plant diseases and protect the environment.

Some recent investigations, have suggested a probable linkage between cytomegalovirus ‎‎‎(CMV) and developing diabetes. But still there is not enough literature to assess the rate of ‎‎this association. To this purpose, in the present study for detecting CMV genome, serum ‎samples ‎of 50 type 2 diabetic patients as the test group with an optimized PCR ‎ reaction ‎were ‎tested. Sex, age and A1C parameter related to this group were recorded too. The ‎‎specificity of the PCR test was 100% and its sensitivity was 100 copy of the viral genome ‎‎in the sample. The related results were compared with the control group that was included ‎‎‎50 non-diabetic participants. The CMV genome did not find in None of these 100 samples. ‎‎No related effects were observed between sex or amount of A1C and association of CMV ‎‎genome in these patients. However, it seems that the age parameter is effective in this ‎‎regard. Comparing these participants with some other similar research suggest that this ‎‎association rate is not very high and the virus only in elderly age can be considered as a ‎‎‎probable risk factor. Thus, for managing diabetes should be more concentrated on ‎the ‎‎well-known factors such as obesity or unhealthy lifestyle.‎

Antibacterial activities of kefir beverage are attributed to kefiran polysaccharide. The aim of this study was to investigate the effect of type of milk, fermentation time, temperature and stirring conditions on antibacterial activity of extracted kefiran from kefir grains. Kefir grains were added to full-fat and non-fat milk. Fermentation was carried out at 25°C and 37°C under stirred and non-stirred conditions. After 24, 48, 72 and 120 hours, the grains were separated from kefir extract and kefiran was extracted. The antibacterial activity of extracted kefiran was carried out by well method. Fermentation time had a significant effect on the inhibition zone of all tested bacteria. Milk type had significant effect on antibacterial activity of kefiran samples against tested bacteria except S. dysenteriae. Fermentation temperature had a significant effect on the inhibition zone of E. coli and B. cereus, but stirring conditions only had significant effect on inhibition zone of B. cereus. Considering all factors and their interactions, in order to extraction of kefiran with higher antibacterial activity is recommended, fermentation in full-fat milk. Also, to achieve higher antibacterial activity against B. cereus, E. coli, S. dysenteriae, and S. aureus, is recommended fermentation time for 24, 48, 48 and 120 hours, respectively. Fermentation at 37°C compared to 25°C and under stirred compared to non-stirred conditions did not create noticeable differences in the antibacterial activity of extracted kefiran from kefir grains. Fermentation conditions had significant effect on antibacterial activity of extracted kefiran from kefir grains.

Among bacteria, lactic acid bacteria are the most common type of bacteria that have been introduced as probiotics. These bacteria are effective in treating rotavirus diarrhea, reducing blood sugar, blood pressure, cholesterol, preventing colon and small bowel cancer, liver, intestinal inflammation, infections, acute diarrhea, and the growth and proliferation of harmful bacteria, as well as causes to strengthen the immune system, help digestion and absorption of minerals and vitamins. In this research, samples were taken from 60 Oscar fish. To achieve this goal, lactic acid bacteria were duplicated by specific primer pairs, 16s rDNA gene of Lactobacillus acidophilus bacteria using PCR; and Lactobacillus acidophilus was identified using a specific band , and its antagonistic effect on Pseudomonas aeruginosa was investigated by disk diffusion methods, so that halo diameter equal to 1.4mm was observed at a dose of 50 μl. Then the MIC and MBC of each metabolite were determined. It was found that increasing the dose of Metabolite Lactobacillus acidophilus increases the effect on Pseudomonas aeruginosa.

The colonized microorganisms in the fish gastrointestinal (GI) tract have recently received particular attention as a probiotic. Therefore, we aimed to identify potential probiotic yeasts from the GI tract of the beluga (Huso huso). The fish were randomly caught from beluga-breeding ponds. The isolated yeast strains were investigated for some properties of probiotic potentials, including tolerance to acidity and bile salt (Oxgall). Yeast strains with probiotic potentials were identified to species level using polymerase chain reaction and sequencing the internal transcribed spacer regions of rDNA. Seventeen different yeast strains were isolated from the beluga's GI tract based on macroscopic and microscopic characteristics. Nine yeasts (52.9%) could tolerate acid (pH = 2) for up to 3 h. Among acid-resistant yeasts, four yeasts could tolerate bile salts for up to 8 h. By comparing the obtained sequences with reference sequences in GenBank, all strains were identified as Candida parapsilosis. Sequence data of each strain were assigned in GenBank under the accession numbers. Identifying the fungal microbiota of healthy fish and determining their probiotic prospects can help us use them in aquaculture. Further extensive studies are recommended to identify fungal-biota with probiotic potential in more fish species.

Among metal nanoparticles, silver due to its high electrical and thermal conductivity and being profoundly anti-bacterial and inexpensive has more importance in comparison with other metals such as gold and platinum. Many acidophilic bacteria can be effective in regenerating many of the nanoparticles due to their metabolism. Experimental samples were collected from Faraman Dairy Factory in Rasht industrial town in May 2019. After isolation and molecular identification to investigate the possibility of biosynthesis of silver nanoparticles, isolated microorganisms were cultured in liquid medium NB, LB and MRS to compare their yield. After incubation time for 24 hours, the silver nitrate salt was added separately to supernatant and material that dissolves in liquid. Characteristics of silver nanoparticles produced by Transmission Electron Microscopy, XRD and ultraviolet spectrophotometer (UV-Vis) were investigated. The results gained from the study displayed that the isolated Acetobacter and Pediococcus bacterial strain could produce silver nanoparticles in LB medium. It was also found that the Acetobacter and Pediococcus bacteria could not produce silver nanoparticles in NB and MRS culture media. The study showed that the Acetobacter bacteria in the supernatant phase and the precipitate phase of LB culture medium could produce silver nanoparticles. It was also found that the Acetobacter bacteria could produce silver nanoparticles. Also, the study showed that the Pediococcus bacteria just in the supernatant phase of LB culture medium could produce silver nanoparticles. It was also found that the Pediococcus bacteria could produce silver nanoparticles with sizes of 100 nm and 50 nm.

Fungal infections are a major health problem worldwide due to their high prevalence. Proper disinfection is the most effective way to control such infections. The aim of this study was to determine the frequency of fungi isolates from sport mats and to investigate antifungal properties of oregano essential oil against the isolates. In this cross-sectional study, 48 samples were collected from six sports clubs between spring and summer 2020. The samples were analyzed using the sterile carpet method (4×4). After microscopic examination and mycological culture, the antifungal effect of oregano essential oil was evaluated using the dilution-neutralization method according to the protocols of Iran’s national standards 2824 and 9899.Overall, fungal isolates were found in 23 samples (47.9%), of which 56.6% were dermatophytes and 43.4% were non-dermatophyte species. Trichophyton tonsurans (34.8%) and Aspergillus niger (21.8%) were the most common dermatophyte and non-dermatophyte isolates, respectively. The oregano essential oil at concentration of 400 mg/ml, inhibited growth of 65% of non-dermatophyte isolates (p <0.05). This effect was more profound against Candida albicans. However, the essential oil had no significant effect on dermatophytes (P>0.05). Given the satisfactory antifungal effect of oregano essential oil in high concentration, it is suggested to use this essential oil as a natural disinfectant to control growth of non-dermatophyte fungi in sports clubs.