دو ماهنامه میکروب شناسی پزشکی ایران
سال چهاردهم شماره 3 (خرداد و تیر 1399)

Chitosan is a natural polymer with special properties that are prepared and purified in the industry of crustaceans. In this study, Trametes versicolor fungus, which was obtained from the forests of northern Iran, was used due to its medicinal properties, and the extracted chitosan of this fungus was optimized and its antimicrobial properties were investigated.

To increase chitosan, four influential NaOH parameters, time, temperature, and biomass to NaOH ratio were performed by the Taguchi method. Fourier Transformed Infrared Spectrometry (FTIR) was identified, and the antibacterial properties of the disc release method were investigated against Escherichia coli and Staphylococcus aureus bacteria and the bacterial non-growth halo by millimeters.

The optimal conditions of the variables were: 5.94 Molar, 4 hours, and 40 minutes, 65.6 degrees Celsius, and 1:25 ratio, respectively. Under these conditions, the amount of chitosan produced was equal to 0.261 g/L and the degree of deacetylation 78% was obtained. The antibacterial properties against E. coli gram-negative bacteria and S. aureus gram-positive bacteria were found to be 12±1 and 18±2, respectively.

Evidence has shown that four parameters had a positive effect on more chitosan production and the S. aureus is more sensitive to the resulting chitosan.

Septicemia is the most important cause of mortality, especially in hospitalized patients, due to the influence of the immune response by infection. NLRP1 (Nod-like receptor P1) is an intracellular receptor that recognizes microbial-dependent molecular patterns. The main intracellular mechanism of anti-septicemia is still being investigated. The purpose of this study was to evaluate the expression of NLRP1 genes in patients with septicemia compared to healthy controls.

This cross sectional study was done on 40 blood samples in patient with septicemia and 40 healthy controls using quota sampling. Bacterial species were identified by microbial culture. NLRP1 gene expression was evaluated using Real Time PCR technique.

Four bacteria such as Escherichia coli, Staphylococcus aureus, Acinetobacter baumannii and Pseudomonas aeruginosa reported for causes of septicemia. The results also showed that the expression of NLRP1 inflammasome at mRNA level was significantly increased in patients with septicemia compared to healthy controls. NLRP1 gene expression was not different among patients with different bacterial infections.

NLRP1 appears to be an important receptor against bacteria during bacterial bloodstream infection, and further research, particularly in reducing the expression level of NLRP1 molecules, may play a key role in blood decontamination.

Pertussis is still one of the major public health problems. The increase of the disease emerged in recent decades due to the replacement of the reactogenic whole cell vaccine with the safer acellular vaccine and the genetic diversity of the bacterium. As outer membrane vesicles (OMVs) obtained from Bordetella pertussis contains surface immunogenic antigen in its structure, it has an acceptable characteristic that could be considered as a good candidate for pertussis vaccine.

Vaccinal strain BP134 strain of B. pertussis was cultured under standard conditions and OMVs were isolated by modifying the method without the use of ultracentrifuge. The isolated vesicles were examined by transmission electron microscopy and protein content was measured by the Bradford method. The expression of virulence factors was confirmed by SDS-PAGE and protein expression was confirmed by Western immunoblot. Pyrogenicity test and abnormal toxicity test were performed on extracted vesicles.

The morphology of the vesicles was confirmed in the range of 40 to 200 nm. The protein concentration of the extracted vesicles was determined as 600 μg. Expression analysis by SDS-PAGE and western blot confirmed the presence of virulence factors, pertussis toxin, filamentous hemagglutinin, and pertactin using monoclonal antibodies in OMVs of the vaccinal strain. Pyrogenicity test and abnormal toxicity test were negative.

The proposed method is a simple and efficient method for isolation of the B. pertussis OMVs. The OMVs extracted from B. pertussis could be a candidate for a new generation of pertussis vaccine alone or in combination with adjuvants to design future acellular vaccines.

Today, with the development of human life and the overwhelming fall of antibiotics and uncontrolled bacterial resistance, the need to find materials with antimicrobial effects is felt more than ever. Nanotechnology has created a new opportunity to investigate the antimicrobial effects of nanomaterials.

In this study, using hydrothermal and microwave auxiliary chemicals, polylactic acid / calcium oxide nanostructures were prepared and the physicochemical and microbial properties of these nanostructures were evaluated. Bacterial strains were obtained from the Scientific and Industrial Research Organization of Iran, the collection center of industrial microorganisms.

Physicochemical characterization of optimized polylactic acid / calcium oxide nanostructures showed the antimicrobial effect of nanoparticles on 3 strains gram-positive bacteria Micrococcus luteus (PTCC 1110), Bacillus subtilis (PTCC 1023), Staphylococcus aureus (PTCC 1112) and 4 strains gram-negative bacteria Escherichia coli (PTCC 1330), Klebsiella pneumonia (PTCC 1053), Serratia marcescens (PTCC 1621), Pseudomonas aeruginosa (PTCC 1074). In this study, the observed MIC (minimum growth inhibition concentration) observed for both Gram-positive and Gram-negative bacteria ranged between 0.5
<mic≤8.

Antimicrobial effect of polyelactic acid / calcium oxide nanostructures was observed on all the mentioned bacteria except E. coli. It is recommended to conduct microbial and cellular studies on these nanomaterials.</mic≤8.

Smartphone applications play a pivotal role in management, providing care and preventing infectious diseases. It also has the potential impact on supportive and self-care. This study aimed to identify the requirements for a smartphones self-care system to prevent corona-virus (COVID-19).

This was a descriptive study performed in two main stages in 2020. At the first stage, to recognize the requirements for a smartphones self-care system, similar articles were searched and identified. In the second stage, the identified requirements were validated through a researcher-made questionnaire. The sample size of the study consisted of infectious diseases specialists of Urmia University of Medical Sciences. The collected data was analyzed using descriptive statistics (mean and frequency).

Requirements of the self-care system were identified in four areas: "demographic data, clinical requirements, self-care strategies, and technical characteristics". Also, according to the research community, 5 data elements for demographic data, 11 data elements for clinical requirements, 5 data elements for self-care strategies, and 11 data elements for technical characteristics were selected.

Applying the requirements and suggested strategies in the present study can improve self-care skills to prevent corona-virus, symptoms management, motivate and reduce stress, increase personal hygiene and communication with health care providers.

 Acinetobacter baumannii is one of the most common challenging pathogens in causing serious infections in intensive care units of modern hospital systems around the world and poses a serious threat to public and patient health. This study aims to analyze the network of scientific and empirical collaborations of A. baumanniii researchers in the last three decades.

 The present study was performed using the Co-citation analysis technique. All A. baumannii publications indexed in the Web of Science Core Collection for the period 1990-2019 are the statistical population of the study. After an advanced search, 4473 documents were retrieved. A total of 18343 authors contributed to the publication of the retrieved documents. Ravar PreMap 1.0.0.0, NetDraw, and UCINET 6.528.0.0 software were utilized for data analysis.

 Data analysis showed that the global publication of A. baumannii has risen. "Clinical Infectious Diseases," was the best journal, and "Seifert, Harald," the most influential researcher, and "Seifert, Harald * Higgins, Paul G," were identified as the best co-citation pair. Top researchers in A. baumannii were "Beceiro," "Alejandro," "HSU Li Yang," and "Seifert, Harald," respectively, based on degree, betweenness and closeness centrality indicators.

Analysis of social networks A. baumanniii presents an objective and realistic view to experts and planners. Also, the structure of A. baumannii's internal relationships and researchers' connections is determined objectively. Finally, researchers get acquainted with journals, scientists and organizations that are proliferated and effective and plan to collaborate with them in the future

 Klebsiella pneumoniae has received attention due to a wide range of diseases and antibiotic resistance.The resistance to fluoroquinolones in gram-negative bacteria is often due to chromosomal mutations in the gyr and par genes. This research aimed at investigating the pattern of fluoroquinolone resistance and its relation with a mutation in the parC gene among clinical isolates of K. Pneumoniae.

In this descriptive-analytical study, 95 K. pneumoniae, after biochemical and molecular diagnosis, were evaluated for resistance to different antibiotics by disk diffusion agar according to CLSI recommendations and screening for ciprofloxacin-resistant isolates. Mutation in the ciprofloxacin resistance determinant region of the parC gene of K. pneumoniae resistant to ciprofloxacin was performed by PCR amplification and then amplified fragment sequencing and finally with the standard bacterial genome sequencing available at NCBI site, became BLAST through online software, Insilico, and Clustalw2.

 The result of the antibiogram showed implies an expansion of MDR bacteria. 3.1% of isolates were resistant to all 13 antibiotics studied and 24.2% were ciprofloxacin-resistant. The highest and lowest percentages of antibiotic resistance were determined for ampicillin and amoxicillin (98.9%) and imipenem (13.6%), respectively. Sequence analysis of the parC gene showed that of 23 isolates resistant to ciprofloxacin, 16 isolates at codon 80 (I80S), one at codon 84 (E84K) were and 3 isolates also had frame-shift mutations.

 Mutations in the parC gene can be one of the major contributors to resistance to fluoroquinolones and increased MDR bacteria and nosocomial infections.

The Coronavirus disease 2019, identified by Chinese researchers to be the caused by a novel enveloped betacoronavirus, Severe Acute Respiratory Syndrome Coronavirus- 2 which was first isolated in Wuhan, China has been declared a global pandemic by the world health organization. The virus has several structural proteins that contributed to its pathogenesis such as spikes, membrane, envelop and nucleocapsid protein facilitating its attachment, entry and cell-to-cell transmission. The virus is readily transmitted through human-to-human contact and there is presently no approved vaccine for its prevention. This study was carried out to review the epidemiology of Severe Acute Respiratory Syndrome Coronavirus- 2, its host and reservoir, pathogenesis, transmission, clinical manifestation and potential treatment options for the infection.