نشریه میکروب شناسی پزشکی ایران
سال سیزدهم شماره 5 (آذر و دی 1398)

Pharmaceutical products are classified into two groups according to the microbiological point of view: 1) sterile products and 2) non-sterile products. The sterilized term refers to the products that are free of any microorganisms, their production were done under aseptic conditions, but the production of non-sterile products were not under aseptic conditions; therefore, they are not free from microorganisms; for this type of products legal authorities defined microbial limit ranges. The contamination of medicinal products by microorganisms can lead to adverse changes such as: change in physical attribute (appearance, color, smell, and viscosity), reduction of therapeutic effects, development of disease and ultimately the loss of consumer reliance. There have been reports about presence of unauthorized microorganisms in non-sterile medicinal products, which has led to more research and attention in this regard. In this paper, the methods for controlling the microbial quality of non-sterile drug products have been reviewed based on the latest version of United States’ Pharmacopoeia, including , , and general chapters that can be used as a reliable source for researchers in the pharmacy industry and drug control labs.

Aquatic ecosystems are an important source of nontuberculous mycobacteria (NTM) that can cause different diseases in human. Since culture of mycobacteria needs long-term incubation, fast-growing microorganisms and contaminants in the environment usually prevents the isolation of mycobacteria. Here, we compare different treatment protocols and describe a method that increases the recovery and improve the culturability of NTM from aqueous samples.

A total of 35 samples from the water sources like tap water, and medical devices such as manometer, dialysis devices, nebulizers, ventilator and dental units were collected. Containers containing 50 mL of the sample were immediately transferred for culture on Lowenstein-Jensen medium to the laboratory and examined. For better isolation of NTM, different concentrations of NaOH, sodium dodecyl sulphate (SDS), cetylpyridinium chlorid (CPC), oxalic acid and cyclohexamide in culture media were examined.

Culture media with 1% solution of NaOH, 3% SDS and 5% oxalic acid was completely effective to eliminate the contaminants and it also showed the lowest inhibitory effect on mycobacteria. The concentrations between 0.3 gr to 1 gr of cyclohexamide had the best inhibitory effect on growth of fungi.

Culture media with NaOH 1%, SDS 3%, 5% of oxalic acid and 0.3-1 gr cyclohexamide can increase the recovery and improve the culturability of NTM from aqueous samples.

Due to their high amount of carbohydrate and enough moisture, cereals are a good environment for the growth of toxigenic fungi. Because of the carcinogenicity and mutagenicity of mycotoxins, preventing them from entering the food chain is essential. Therefore, the present study was conducted to determine the amount and type of contaminated imported cereals and rice produced in Khuzestan province

In October and November 2015, a total of 50 random samples of rice was collected from paddy fields. Aspergillus were identified based on available diagnostic criteria and PCR. The amount and type of aflatoxin in rice samples and mycotoxins in imported cereals (winter 2015 to autumn 2016) were evaluated by HPLC

Based on one sample t-test and comparing the mean of mycotoxins contaminating cereals in different seasons with national maximum standard, the amount of mycotoxins in barley and wheat were within the standard range but %8.4 of corn was higher than the permitted level (ppb5). Analysis of aflatoxins in rice also showed that 16 samples were contaminated with aflatoxin B1.  Aspergillus flavus was the major pollutant (%42.1) isolated from rice.
 

Aspergillus flavus is the major producer of aflatoxin B1 in domestic rice. Examination of imported cereals also showed high rates of fungal growth and production of secondary metabolites, possibly due to inadequate storage conditions, high temperature and humidity.   Therefore, it is recommended to strengthen the monitoring tools in the processing and storage of rice and cereals.

 Asparaginases are known to be the cornerstone for the treatment of acute lymphoblastic leukemia (ALL) and are used for treatment in all pediatric regimens as well as in the majority of adult treatment protocols. Clinical hypersensitivity reactions against commercially available asparaginase have resulted in the failure in the treatment of ALL in more than 60% of cases. Thus, it is required to search for serologically different asparaginases from new organisms for patients exhibiting sensitivity to one formulation of asparaginase.

   The experiments were conducted in 250 mL flasks containing 100 mL of M9 broth medium and incubated at 35˚C for 48 h with shaking 100 rpm. The bacterium produced an extracellular asparaginase enzyme in which a heavy metal-rich medium was influenced—considering that this idea, enzyme activity was marked at the presence of metal salts such as FeCl3, ZnCl2, CoCl2, MgCl2, CaCl2, CuSO4, KCl and NaCl with the different concentrations as 0-3% W/V.

   In this research, we isolated a bacterium that belonged to staphylococcus species named strain MGM1 and deposited to NCBI by accession number of KT361190. The results showed that Na+, Fe2+, and K+ were inducted to enzyme production, and Zn2+ had no effects, while Cu2+, Ca2+, and Mg2+ inhibited enzyme activity when their concentrations increased up to 1%. 

This study aimed to investigate the effects of different ions on the activity of the enzyme in the blood and fluid of the body. Such compounds are vital elements in the blood, and therefore, their effect on the enzyme is very important, So This experiment suggests that asparaginase could be affected by the metals.

Application of nanoparticles in the removal of pathogenic bacteria is very important. The use of these materials can be appropriate for controlling pathogens and food-borne diseases. The purpose of this study was to synthesize magnesium oxide nanoparticles and investigate its antibacterial effect on several bacteria causing food poisoning.

Oxide magnesium nanoparticles are synthesized by chemical deposition method. In order to control the quality and morphology of samples, XRD and SEM methods were used. The effect of different concentrations of nanoparticles on Staphylococcus aureus, Salmonella enterica and Bacillus cereus was evaluated by Agar well diffusion technique and the antibiotic resistance patterns of the bacteria used were also examined.

MgO nanoparticles had an extensive antibiotic resistance but were effective on all bacteria and the minimum inhibitory concentration of growth on Staphylococcus aureus, Salmonella enterica and Bacillus cereus was 0.75, 1.25, and 5 mg/mL and the minimum bactericidal concentration of them were determined to be 0.15, 2.5 and 10 mg/mL, respectively.

MgO nanoparticles exhibited remarkable antibacterial activity against food poisoning causing bacteria and can be used as an antibacterial agent more effectively.

 Today, despite improved food safety, nearly a quarter of the population is at risk for foodborne diseases. Therefore, the use of lactic acid bacteria and their metabolites due to their potential health benefits, safety and production of natural antimicrobial compounds is an appropriate solution to reduce microbial spoilage of food.

   In this research, lactic isolates were first identified by PCR method and Micro-dilution method was used to evaluate the antimicrobial activity of the Cell Free spent Medium (CFSM).

   The sequencing of PCR products showed that the species identified were Lactobacillus and Enterococcus species. The results of the evaluation of the antibacterial properties of the CFSM on the growth of Gram-positive bacteria showed that all isolates were able to prevent the growth of these pathogens and their inhibitory percentages varied from 86.81 to 38.81 percent. The results of inhibitory effects of lactic isolates on the growth of two gram-negative bacteria of Escherichia coli and Salmonella enterica also showed that the inhibitory levels of the isolates were varied from 2.43 to 36.43 percent and 14.1 to 31.97 percent, respectively. Comparison of the inhibitory effect of lactic isolates on pathogenic bacteria showed that the inhibitory effect of all lactic isolates on gram positive bacteria was significantly (P <0.05) more than their effect on gram negative bacteria.

  The results of this study showed that native dairy lactic acid isolates and their metabolites can be used as biological preservatives or in combination with synthetic preservatives in the food and drug industry.

Schizophyllum commune, is one of the important medicinal-fungi foods in the world. Due to its important constituents such as extracellular and intracellular polysaccharides, it is widely used in industry and medicine. One of the important polysaccharides of this fungus is chitin-glucan complex (CGC). The aim of this study was to investigate the growth of native fungus Schizophyllum commune isolated from northern forests of Iran and to optimize its CGC production in submerged cultivation.

Growth kinetics studies of native Schizophyllum commune fungi of Iran and CGC production were performed and growth curves were plotted. In order to increase CGC production, optimization of culture medium was done by investigating independent variables of pH, inoculum percentage and aeration percentage by response surface methodology.

The results showed that the specific growth coefficient of Iranian native Schizophyllum commune (max µ) was 0.991-day. Tenth day was also selected as the best time for growth and production in the submerged medium. In optimum conditions, initial pH of 8.92, percentage of inoculum 9.99 and aeration percentage of 150 was obtained. After 10 days, the amount of dry cell weight was 13.05 g/L and the amount of chitin-glucan complex produced was 2.9 g/L.

Investigation of kinetic parameters of growth and production showed that the experimental data are in accordance with the logistic growth model with R2=0.9665 and the  Luedeking and Piret  model for production with R2 = 0.9439. The results also show that the initial pH has a significant effect on the growth of this fungus.