Medical Laboratory Journal
Volume:10 Issue: 2, Mar-Apr 2016

Typing of bacteria is an important part of epidemiological studies on nosocomial infections. Bacterial identification methods have dramatically improved in recent years, which is mainly due to advancements in the field of molecular biotechnology. In many cases, molecular techniques have replaced phenotypic typing methods.
Currently, a wide range of bacterial typing techniques is used that are different from one another in the aspects of study objectives, costs, reliability and discriminatory power. None of the typing methods can achieve all desired objectives of a study alone.
Different typing methods are used for various purposes including: 1. confirmation of epidemiological relationships in spread of an infection, 2. providing epidemiological hypotheses about epidemiological relationships between bacteria in the absence of epidemiological data, 3. describing the distribution of bacterial types and identification of affecting factors. Inferences of epidemiological studies depend on the chosen typing technique and objectives of the study.
Therefore, the typing technique can be useful and effective in increasing our understanding of the pathogenesis, transmission and prevention of possible diseases. The aim of this study was to evaluate various methods of molecular typing of bacteria and to compare these methods from different aspects.

Chlamydia trachomatis is one of the most common causes of genital infection in men and women. Genital chlamydial infections in women are clinically asymptomatic in 70-80% of the cases; therefore, the lack of timely diagnosis and treatment leads to complications such as infertility and ectopic pregnancy. The aim of this study was to evaluate the frequency of chlamydial infection in symptomatic and asymptomatic women in the Golestan province.
This cross-sectional study was conducted on 150 cervical swab samples obtained from 150 women referred to the clinic, after obtaining written consent and completion of questionnaires. The swab samples were transferred to laboratory in phosphate-buffered saline solution and DNA extraction was carried out using phenol-chloroform and boiling methods. The frequency of chlamydial infection was evaluated by PCR.
None of the tested samples were found as Chlamydia-positive.
The findings require that some more extensive research with larger sample sizes and dispersed population be performed to determine the true prevalence. Considering the serious complications of chlamydial infections and its asymptomatic nature, a highly sensitive and specific method such as PCR should be used to detect Chlamydia. It is suggested that this method be used along with a complementary test to obtain the results that are more accurate. Furthermore, conducting simultaneous studies on other populations at risk will be very helpful in obtaining representable national data.

Staphylococcus aureus is the most common and important infectious agent. This bacterium can enter the bloodstream and cause some complications in the intensive care unit (ICU).This organism can frequently be found in the nose and transmitted by the carriers. This study aimed to determine the efficiency of eradicating S. aureus from the nose of ICU personnel in reducing the risk of S. aureus infections in the Panje Azar Hospital in Gorgan, Iran.
Sampling was done using sterile swabs collected from the anterior nasal passages.All samples containing Gram-positive cocci were sent to the laboratory of Faculty of Medicine for identification and evaluation of methicillin resistance. All S. aureus nasal carriers were treated with mupirocin ointment b.d for 5 days. The Samples were cultured again after five weeks to evaluate the eradication of S. auerus from the nose of subjects.
Overall, seven ICU personnel (11.7%) were S. aureus carriers. Two isolates (3.3%) were found as methicillin resistant using both methods of disc diffusion and PCR. The frequency distribution of positive cases indicated a significant difference in terms of work experience (P = 0.012).
The findings show that treatment of carriers with 2% mupirocin topical ointment eradicates S. aureus from the nose. No S. aureus isolates was found in reculture of nasal samples. Treatment of healthy carriers can significantly reduce the risk of infections caused by the bacterium in the ICU.

One of the main tasks of clinical microbiology laboratories is to determine antibiotic resistance profiles in common pathogens and ensure the selection of effective antibiotics for certain infections. The aim of this study was to compare the methods of disk diffusion, broth microdilution and modified Hodge test in Escherichia coli isolates from urinary tract infection and diarrhea for susceptibility testing against beta-lactam antibiotics in Kerman, Iran.

In this study, 432 E. coli isolates were collected from diarrhea (216 isolates) and urinary tract infection samples (216 isolates). The antibiotic susceptibility testing methods of disk diffusion, broth microdilution and modified Hodge test were performed according to the Clinical and Laboratory Standards Institute guidelines.

The findings of disk diffusion method showed that resistance to cefotaxime, ceftazidime, aztreonam, cefepime and imipenem was 51.15%, 30.55%, 24.30%, 15.27% and 1.85%, respectively. In the disk diffusion test, 51.15% of the isolates were resistant to at least one antibiotic, all of which were later evaluated by the broth microdilution method. Moreover, 52.94%, 17.19%, 13.12% and 0.90% of the isolates were resistant to cefotaxime, ceftazidime, cefepime and imipenem, respectively. All of the isolates were evaluated for the production of carbapenemase enzyme by the modified Hodge test and none of the isolates were found as positive.

This study shows that performing carbapenem tests is very challenging, and laboratories are recommended to use secondary and independent antibiotic susceptibility tests such as modified Hodge test to confirm the carbapenem-resistant results.

Lactic acid bacteria are Gram-positive, catalase-negative, nonsporulating, either rod- or coccus-shaped bacteria that have beneficial effects on their hosts by producing antimicrobial substances such as lactic acid, hydrogen peroxide, bacteriocins and biosurfactants. Bacteriocins are antimicrobial peptides that are produced by bacteria and can inhibit the growth of other bacteria.

In this experimental study, bacteriocin production by Lactobacilli as known probiotic strains was evaluated in different physicochemical conditions. Antagonistic activity was evaluated using quantitative method of Microscale Optical Density Assay (MODA). After neutralization of acid and treatment with various enzymes, temperature, pH and NaCl conditions, the antimicrobial activity of culture supernatant fluid of Lactobacillus acidophilus and L. plantarum was investigated against pathogenic Proteus.

The culture supernatant fluid of Lactobacilli was sensitive to proteolytic enzymes with relatively good stability to temperature. The antimicrobial activity was also present due to production of bacteriocin under different NaCl conditions (1 to 4% NaCl) and pH range of 5 to 8.

It seems that the antimicrobial liquid of Lactobacillus strains contains bacteriocin, which shows antimicrobial effects against pathogenic strains of Proteus. To investigate further this effect, some complementary studies should be performed.

Considering the increasing tendency of public towards green consumption and the dangers of artificial additives, this study aimed to assess antibacterial activity of essential oils of Cinnamomum zeylanicum, Mentha piperita L., Zataria multiflora Boiss and Thymus vulgaris against three important pathogenic and spoilage bacteria (Pseudomonas fluorescens, Erwinia carotovora and Escherichia coli).
◦After obtaining the essential oils from Magnolia Co., their antimicrobial activity was assessed using broth microdilution method by determining the minimum inhibitory concentration (MIC50, MIC90) and minimum bactericidal concentration (MBC). All experiments were performed in triplicate and the data were analyzed using the GraphPad software and Duncan's new multiple range test.
◦All essential oils showed antimicrobial activity in a concentration-dependent manner. Increasing the concentration of essential oils from 0.01% to 4% (v/v) significantly enhancing the antibacterial activity. The statistical calculations and comparison of data showed that the essential oils of C. zeylanicum and Z. multiflora performed better compared to the other two essential oils, due to having lower values of MIC50 (≤0.1%), MIC90 (≤0.4%) and MBC (≤1%) (P

Cutaneous leishmaniasis is a parasitic disease and a health problem in different parts of Iran, especially two cities of Mashhad and Chabahar. Due to morphological similarities of most Leishmania species and difference in reservoirs of L. major and L. tropica, it is necessary to determine the parasite specie to combat the disease. Thus, this study used gene sequencing and genotyping of 70-kDa heat shock protein (HSP70) to differentiate the two species of Leishmania.
In this descriptive-analytical study, microscope slides and cultures were prepared from 43 patients suspected of cutaneous leishmaniasis in Chabahar and Mashhad. PCR was performed after genomic DNA extraction and then PCR products were sequenced and analyzed.
Of the 43 patients studied, 32 direct smear and culture (74.4%) were positive and 11 (25.6%) showed negative results, and were therefore excluded from the study. Using HSP70-specific primers, 1962 bp and 1152bp bands were observed for HSP70 of L. major in Chabahar and L. tropica in Mashhad, respectively. Based on the results, there were 18 nucleotide differences between HSP70 of L. major in Chabahar and L. tropica in Mashhad.
Due to the morphological similarities between Leishmania species and inability to differentiate species through parasitological methods, the HSP70 gene can be used for identification of the species, and prevention and treatment of the disease.

Chabahar is in Southern Iran located near the Iran-Pakistan border. Since leishmaniasis is an emerging disease in this region, this study aimed to diagnose the disease and identify different species of Leishmania parasite in the patients referred to the central laboratory.
This descriptive cross-sectional study was conducted in 2011-2012 on patients referred to the central laboratory in the city of Chabahar. The sampling of lesions, slide preparation, culture and PCR specific for kinetoplast DNA (kDNA), extracted from the media and slides, were performed. The data collected by a questionnaire were analyzed by the SPSS software.
The resulted bands from the 48 tested cutaneous leishmaniasis isolates were compared with the standard strains of Leishmania tropica, L. infantum and L. major. All 48 investigated bands were in the 620bp region, which is related to L. major.
Since PCR has high sensitivity and specificity, it is recommended to use kDNA (present in a unique organelle called kinetoplast) for the routine diagnosis and treatment of the disease.

Measurement of amino acids is an important tool for metabolic studies and evaluation of patients’ clinical condition. The aim of this study was to analyze the plasma amino acids using reverse phase high performance liquid chromatography techniques (RP-HPLC) with pre-column derivatization by o-phthalaldehyde (OPA) in combination with 3- mercaptopropionic acid (3-MPA).
Overall, 107 neonates and babies suspected of having metabolic disorder were enrolled in this study. The level of amino acids in plasma samples was analyzed within 65 minutes by HPLC with pre-column derivatization by OPA/3-MPA. This was a gradient RP-HPLC method that was performed using two solvents with a ratio of methanol and sodium acetate. L-norvaline internal standard was used as the reference peak for amino acids. Standard mixture of amino acids was used to determine the concentrations of amino acids.
According to the values of coefficient of variation obtained for each amino acid, the results indicated a good chromatographic separation of amino acids by this method. The use of OPA/3-MPA derivative reagent increased the efficiency and resolution of amino acids chromatographic separation.
Due to simple preparation and accurate assessment, determination of plasma amino acids using OPA/3-MPA derivatives and RP-HPLC is a suitable method in many clinical samples.

The current challenge of diabetes mellitus is to prevent its complications. These complications are directly associated with hyperglycemia in diabetics. The HbA1c measurement is essential for long-term glycemic control. Synchronization of HbA1c measurement is important in order to avoid discrepancies between results reported by laboratories. This study aimed to evaluate the accuracy, precision and agreement of five HbA1c measurement methods with HPLC reference method.
HbA1c levels of 55 samples were measured using six methods of microcapillary electrophoresis (Sepia), enzymatic method (Pishtaz Teb), immunoturbidometry (Pars Azmoon), boronate affinity (Nycocard), immunofluorescence (ichroma) and Tosoh G8 HPLC.
The five tested methods showed a good agreement with the HPLC method with correlation coefficient of less than 95%. Regression testing of HPLC method and other methods showed slope of 0.99 (P The Sebia microcapillary method and Pishtaz teb enzymatic method have appropriate accuracy and precision. Therefore, these methods can be used as alternatives to the HPLC method for HbA1c measurement. Other methods such as Pars Azmoon, Nycocard and ichroma have significant shortcomings in terms of accuracy.