دو ماهنامه میکروب شناسی پزشکی ایران
سال دوازدهم شماره 2 (خرداد و تیر 1397)

Based on the frequently reports, final diagnosis of brucellosis is facing delay problem. Significant percentage of hospitalized patients has been under unspecified and mostly single treatment. Therefore laboratory evidence and use of highly sensitive methods have an important role in final diagnosis.
The increasing of brucellosis in recent years is due to increasing livestock infections and insufficient coverage of vaccination; we should also consider absence of active supervision on the distribution of livestock products specifically in local manufacturers and inefficient diagnostic procedures. Lack of coordination between responsible and decision-making centers such as subsidiaries of Ministry of Health and Agriculture has an important role. Unfortunately, despite the publication of numerous scientific papers, especially in the field of epidemiology, no clear picture of the status of brucellosis has been presented by the responsible authorities in Iran.
In this study, we tried to look at the situation of brucellosis in Iran and to find out more about the limitations and advantages of each method by describing the diagnostic properties of each method. The aim of this study is to provide routine diagnosis limitations and errors to undertake necessary revision in diagnostic measures, in particular at the health labs level.

Staphylococcus aureus is one of the most common causes of food poisoning, which due to excessive use of antibiotics has become resistant to different antibiotics. In addition, it is also capable of producing biofilm. The aim of this study was to investigate antibiotic resistance patterns and phenotypic study of biofilm production in S. aureus isolates separated from confectionary pastries in Hamadan.
In this descriptive- cross-sectional study, 370 samples of creamy (280) and dried (90) pastries were collected randomly (May to February 2017). To separate possible microbial contaminations, part of samples were cultivated with conventional microbiological methods. The separated S. aureus isolates were confirmed using polymerase chain reaction (PCR) and nuc gene amplification. The antibiotic susceptibility pattern of all isolates was determined by disk agar diffusion (DAD) method based on CLSI guideline and also, microplate modified method was used to identify biofilm strains.
The results showed that 34.64% of the creamy pastries and 3.33% of the dried pastries were infected with S. aureus. Antibiogram results showed the highest resistance was related to penicillin (90%). In the quantitative study of biofilm production, 42 strains (42%) were strongly adhesive, while 17 (17%) and 41 (41%) strains were weakly adhesive and lacking adhesive ability, respectively.
Consumption of creamy pastries increases the risk of infection with S. aureus and is a serious warning to the health system. Pasteurization and storage of food stuff in the refrigerator, continuous microbial control of pastries and the screening of the confectionary staff can reduce the level of microbial contamination and the risk of staphylococcal poisoning.

Foodborne diseases are one of the major health and economic problems in industrialized and non-industrialized countries. Salmonella serotypes have been considered as one of the most important foodborne pathogens around the world. Poultry and eggs are considered as major sources for different pathogenic Salmonella serotypes. The aim of this study was to investigate prevalence of Salmonella contamination in indigenous and industrial chicken eggs in Khorramabad during 2015-2016.
In this cross-sectional study, a total of 360 (180 indigenous and 180 industrial) eggs were collected from different part of Khorramabad area. The eggs were immediately transferred to microbiology laboratory in aseptic conditions. In order to determine Salmonella, after culture according to the reference conventional methods, the suspected colonies were confirmed using Serotyping and PCR
The results showed that two samples of 180 indigenous eggs (1.1%) were contaminated to salmonella, but there was no contamination in industrial eggs.
The findings of the current study indicated that although Salmonella was not found in industrial egg samples but indigenous eggs produced in small farms may be harmful to consumers and cause the spread of salmonella contaminations in the environment.

Lactobacillus salivarius is a well-known probiotic bacterium, which is commonly isolated from gastro-intestinal tract of human and animals. The objectives of the present study were isolation, molecular detection and antimicrobial characterization of L. salivarius from buffalo’s raw milk.
A total number of 20 buffalo milk samples were collected aseptically from traditional buffalo farms in Urmia city, Iran. Milk samples were cultured and incubated on MRS agar, then suspected colonies were primarily determined according to their appearance and biochemical characteristics. Bacteria species were confirmed by polymerase chain reaction accompanied by restriction fragment length polymorphism (PCR-RFLP) and nucleotide sequencing of 16s rRNA gene. Antimicrobial activity of L. salivarius against pathogenic bacteria including Listeria monocytogenesis, Escherichia coli, Salmonella typhimurium, and Staphylococcus aureus was examined using agar-spot and agar-disk diffusion methods. Cell surface hydrophobicity of L. salivarius was also investigated according to microbial adhesion to xylene and toluene hydrocarbons.
From 60 suspected colonies which were selected according to phenotypic characteristics, 23 colonies were confirmed as lactic acid bacteria based on the molecular identification. Only one isolate belonged to L. salivarius. The antimicrobial activity results showed a significant growth inhibitory effect of L. salivarius on pathogenic bacteria comparing to standard bacteria. L. salivarius had the most inhibitory effect on S. aureus while it had the least inhibitory against S. typhimurium. The hydrophobicity of L. salivarius to xylene and toluene were 55.3% and 55.6% respectively.
Based on the results, the frequency of the Lactobacillus genus s was very low in buffalo milk. In addition, isolated L. salivarius had strong antimicrobial activity against pathogenic bacteria.

In this study graphene oxide based coatings are applied on the titanium substrates in order to improve their biocompatibility and antibacterial properties of titanium substrate.
Chitosan, graphene oxide and their composites separately are coated on the substrates and their hydrophilicity and roughness are measured using contact angle measurement and atomic force microscopy. The coated substrates are then exposed to MG63 osteoblasts and Staphylococcus aureus in order to evaluate the interactions.
The results show that titanium samples that are coated with chitosan and composites have better surface hydrophilicity and higher roughness compared to other samples and uncoated titanium. Cell adhesion is also improved on the coated substrates. Regarding the antibacterial property the composite coating show the best results.
It is concluded that the titanium substrate which is coated with nanocomposite of graphene oxide and chitosan has higher hydrophilicity and roughness that resulted to enhance biocompatibility and antibacterial property. This may lead to a higher success rate in the application of these substrates in maxillofacial implant surgeries.

Microbial contamination is a great threat to human health. Studies have shown that antimicrobial compounds made from a variety of NPs have high antimicrobial activity. The potential effects of nanostructured metal oxides on the reduction of microbial contaminants are well established. The present study aimed to investigate the antimicrobial activities of magnesium oxide nanoparticles in zeolite matrix on Gram-positive and Gram-negative bacteria.
MgO nanoparticles were successfully synthesized from Mg (NO3)2.6H2O in large mordenite matrix through a solid state reaction method. The synthesized samples were characterized by XRD, FTIR, SEM and TEM. Disk diffusion method and MIC were used to evaluate the antimicrobial activity of MgO nanoparticles on Staphylococcus aureus and Escherichia coli compared to commercial antibiotic disks.
XRD results reveal diffraction peaks for each of the two compounds in the nanocomposite. The XRD studies show that the synthesized magnesium oxide NPs have cubic structure. Average size of the NPs was estimated by transmission electron microscopy around 14 nm. Based on the results, these nanoparticles have antimicrobial activity against selected bacteria.
MgO indicate strong antibacterial activity related to alkalinity and active oxygen species. MgO nanoparticles damage the cell membrane and then cause the leakage of intracellular contents which in turn lead to death of the bacterial cells.

Acanthamoeba, the causative agent of granulomatous amebic encephalitis )GAE), is among the most prevalent free-living amoebas (FLA) existing in water, soil and dust. This study was conducted to determine FLA and identify Acanthamoeba genotypes isolated from stagnant water in Kashan, Iran.
In this descriptive study, 138 stagnant water samples were collected from Kashan mosques and public parks. The samples were filtered (0.45µm) and cultured onto non-nutrient agar for the presence of FLA. Acanthamoeba spp. was identified by polymerase chain reaction (PCR) using specific primers, which amplified a 490 bp fragment. Among ten sequenced isolates of Acanthamoeba, different genotypes were determined by sequence analysis. The parameters such as pH, temperature, sampling season and related results were recorded and analyzed using SPSS16.
The rate of FLA was 88.4 %, 59.4% of which were confirmed as Acanthamoeba spp. using PCR method. The rate of Acanthamoeba T4 and T2 genotypes were 80% and 20%, respectively. There was a significant relation between FLA rate and sampling season (P= 0.01). The highest rate of FLA and Acanthamoeba was observed at pH 7. There was no significant relationship between FLA and Acanthamoeba spp. with pH and temperature.
The rate of FLA and Acanthamoeba in stagnant water were high in Kashan. The dominant Acanthamoeba genotype (T4) is pathogen. Due to serious amoeba-induced complications, hygienic education is recommended to increase the public awareness on transmission and health/preventive measurements.

Cryptococcosis is an infection caused by Cryptococcus species. Cryptococcus gattii is mostly isolated from Eucalyptus trees and is acquired via inhalation of basidiospores. The present study was performed to isolate Cryptococcus sp. from Eucalyptus trees and evaluate C. gatti contamination of the Eucalyptus camaldulensis trees in some parks of Tehran and Varamin.
88 trees (leaves, stalk, fruit and soil) were collected from different areas of Tehran, Varamin and Shahr Ray in 2014-2015 during spring and fall. Identification of Cryptococcus sp. were performed based on colony color on niger seed agar medium, urease production, india ink test and pseudohyphae formation on corn meal agar with tween 80. Specific differentiation of Cryptococcus sp. were performed using sugar assimilation by API 20C AUX, disk approaches, colony color on Canavanine Glycine Bromothymol Blue and Cycloheximide-Phenol Red Agar medium.
Results and 6 out of 88 samples of Eucalyptus trees were identified as Cryptococcus sp. Accordingly, four species were identified as Cryptococcus albidus while species of two other isolates were not detectable by used methods. Although Cryptococcus gattii was not isolated from the collected samples, this does not mean that Eucalyptus trees of Tehran are not contaminated.