Abstract

Background and Objective: Swimming pools, which are recreational places, can cause transmission of bacterial diseases, fungal and parasitic infections due to direct contact with various groups of people. We aimed to determine and compare the common microbial indicators in the water of pools and Jacuzzis in Golestan province.

 Material and Methods: the samples were obtained from eight indoor pool and Jacuzzi in Golestan province from July to December 2010, to evaluate the biological and physiochemical parameters.

Results: The residual chlorine in the pool and Jacuzzis was 74.3 % and the 41.1 %, respectively, and the difference was significant; the pH level was 70.4 % and 78.1 %, respectively; the mean of turbidity was 17.8 %, and 9.8 % and the difference was not significant. The samples contaminated with total coliform in the pool and Jacuzzi, respectively, were 4.3 % and 15.2 % and with E. coli were 1.3 % and 11.2 %.

Conclusions: The higher contamination of Jacuzzi is related to the higher temperature and turbidity of water, and more exposure of swimmer with water and less recirculation of Jacuzzi water. The high turbidity, lack of desired residual chlorine and choliform contamination are the main problems of swimming pools and Jacuzzi in Golestan province.

Keywords: Biological indicators, Microbial, Pool, Golestan Province.

ABSTRACT

        Background and Objective: 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.

        Methods: 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.

      Results: 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.

       Conclusion: 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.

Background and Objective: 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 <0.05).
• Considering the high antimicrobial activity of essential oils of C. zeylanicum and Z. multiflora, they can be used as effective food additives with fewer side effects. However, further studies are being conducted on the effectiveness of essential oils on the growth of other microorganisms and their results will be published soon.
• Essential Oils, Antimicrobial, Pathogenic Bacteria, Cinnamomum Zeylanicum, Zataria Multiflora Boiss.

ABSTRACT

        Background and Objective: Lavandula stoechas is a species of native and permanent plants in Golestan province that belongs to the family Lamiaceae. L. stoechas has been used in traditional medicine for treatment of various diseases. The aim of this study was to extract essential oil using steam distillation method from the flowers of L. stoechas collected from Jahan-nama region in the Golestan province, and evaluate its antibacterial activity.

        Methods: Steam distillation (Clevenger) and GC-MS system were used to separate volatile oils and identify the essential oil components, respectively. Two methods of disk diffusion and broth micro dilution were used to evaluate the antimicrobial effect of L. stoechas essential oil. Six bacterial species including Staphylococcus aureus, Bacillus sp., Enterococcus faecalis, Salmonella enteritidis, Escherichia coli and Pseudomonas aeruginosa were tested.

       Results: The essential oil yield was 0.28%. The main components were camphor (71.86%), 1, 8-cineole (4.08%), linalool (3.77%) and borneol (3.19%). The essential oil showed no inhibitory effect on P. aeruginosa and E. faecalis, while it had different inhibitory effects on other bacteria. S. aureus and Bacillus sp. showed the highest sensitivity with inhibition zone diameter of 32 and 29 mm, respectively.

        Conclusion: The results of this study showed that the essential oil of L. stoechas has high inhibitory and antimicrobial activity particularly against Gram-positive bacteria, which may be due to the presence of 71.86% camphor in its composition.

ABSTRACT
          Background and Objectives: Many aromatic plants from the genus Satureja have been used in traditional medicine in north of Iran. This study aimed to determine the ecological requirements for the growth of Satureja mutica Fisch. & C.A. Mey, and evaluate antioxidant and antibacterial activity of ethanolic extract of S. mutica collected from North Khorasan Province, Iran.
         Methods: Aerial parts of S. mutica were collected in blooming stage. Ecological requirements and the traditional uses of the plant were recorded. Ethanol extract of the plant was prepared by maceration. Antioxidant capacity of the extract was measured by three methods of total antioxidant capacity, reducing power and 2,2-Diphenyl-1-picrylhydrazyl, and then compared with standard antioxidants (butylated hydroxyanisole and butylated hydroxytoluene). Antibacterial activity of the extract was studied against nine Gram-positive and Gram-negative bacteria by agar dilution method and determining the minimum inhibitory concentrations (MICs).
         Results: S. mutica is the most common wild aromatic annual herb in north slob and sunny areas around mountains of Bojnord (1020-1300 m). The ecological features of this region are as follows: annual rainfall 308 mm, average temperature 11.5 oC, semi dry cold climate in the sandy clay loam soil, Ec=0.7 desizimence, and pH= 7.30. Ethnopharmacological data showed that this plant has been widely used by rural people as an anti-infective, antispasm and sedative agent that could treat rheumatic pain, migraine, toothache and diarrhea. The ethanol extract of S.mutica had relatively high antioxidant activity with IC50 value of 11.2 mg/ml. The extract also had high antibacterial activity against Staphylococcus aureus, Staphylococcus epidermidis, Bacillus cereus and Enterococcus faecalis, with inhibition zone diameters ranging between 15.1±0.5 and 27.7±0.8 mm and MIC values of 60, 68, 53 and 83 mg/ml, respectively.
         Conclusion: It can be concluded that the extract of S. mutica has favorable antibacterial and antioxidant activity, which could be used as natural anti-microbial agent for treatment of some infection diseases.
          Keywords: Antioxidant, Antimicrobial, Bojnord, Ecological Requirements, North Khorasan, BHT, BHA.

ABSTRACT
       Background and Objective: Nanobacteria are nanometer-scale particles with different shapes, which have been a subject of debate in modern microbiology. They belong to a proposed class of living organisms, specifically cell-walled microorganisms with a size much smaller than the generally accepted lower limit for life. Since some microorganisms are able to continue growth at high temperatures, we aimed to isolate thermophilic bacteria from Gheinarcheh hot spring in Ardabil (Iran) and identify the characteristics of these microorganisms.
       Methods: Microbial mats were found in cultures from Gheinarcheh hot spring in North West of Iran. Synthetic media were prepared and used for isolation of protease-producing thermophilic bacteria, and identification of the features of microbial mats. Cultures were incubated at temperature range of 60-120 oC. Scanning electron microscopy, DNA extraction and polymerase chain reaction were used to further identify characteristics of the microbial biofilms.
        Results: Microbial biofilms of nanoparticles were detected in our samples. Growth of the bacteria increased at all temperatures tested. Results of scanning electron microscopy showed nano-sized particles in the scale of 60 nm. No band was visible in gel electrophoresis of polymerase chain reaction products.
Conclusion: This study is the first to report the presence of hyperthermophilic nanobacteria in Iran.
      Keywords: Nanobacteria, Hyperthermophile, Microbial Mat.

ABSTRACT
Background and Objectives: The resistance of gram-negative bacteria to antibiotics has become a serious problem, which imposes a significant increase in treatment costs. Klebsiella pneumoniae is an important nosocomial pathogen from the Enterobacteriaceae family. The aim of this study was to investigate the frequency and pattern of antibiotic resistance in K. pneumoniae strains isolated from clinical samples.
Methods: This descriptive, cross-sectional study was performed on 150 K. pneumonia strains isolated from different clinical samples such as urine, sputum, blood, ulcers, lung secretions and abdominal abscess. Antibiogram test was performed using the disk diffusion method (Kirby-Bauer). Minimum inhibitory concentration of amikacin, tobramycin and gentamicin was determined via the E-test for 50 strains with high resistance rates.
Results: In this study, the highest rate of resistance was observed against carbenicilin, ceftriaxone, cefepime and streptomycin. K. pneumonia isolates were most frequent in urine and sputum samples. In the E-test, the highest rate of resistance was observed against gentamicin, tobramycin (16µg/ml) and amikacin (64µg/ml).
Conclusion: Based on our results, tigecycline, netilmicin, kanamycin and amikacin are the most effective antibiotics for the treatment of K. pneumoniae infections.
Keywords: Klebsiella pneumoniae, antimicrobial resistance, E-test method

ABSTRACT
             Background and objectives: Antimicrobial resistance is a serious threat to global public health. The overuse and misuse of antibiotics are the most important contributing factors to development of antibiotic resistance. Thus, there is an urgent need to identify and discover new compounds against drug-resistant microorganisms. We have previously synthesized new series of 3-substituted 5H-(1,2,4)triazolo(3',4':2,3) (1,3,4)thiadiazino(5,6-b)quinoxaline derivatives (4a-4f). Here, we evaluate the antimicrobial activity of these derivatives against methicillin-resistant Staphylococcus aureus, S. aureus, Streptococcus pyogenes, Pseudomonas aeruginosa, Escherichia coli, Candida albicans, Candida tropicalis and Candida krusei.
             Methods: The agar well diffusion and agar dilution methods were used for determining inhibition zone diameter and minimum inhibitory concentration during preliminary evaluation of antimicrobial activity.
             Results: All synthesized compounds exhibited antibacterial and antifungal activity against the tested microorganisms.
             Conclusion: Our findings indicate the antimicrobial potential of the six novel synthetic triazolo thiadiazin quinoxaline compounds.
             Keywords: Antimicrobial, Anti-bacterial agents, Antifungal agents, Triazolo, Thiadiazin, Quinoxaline.

Background: Tigecycline susceptibility testing and reporting remain enigmatic due to the lack of established guidelines. Disc diffusion, as a method of performing susceptibility testing, is more widely accepted worldwide due to its ease of use. Limited published literature is available from India on the utility of this method, especially in a cancer care setting. Hence, this study was conducted to evaluate the performance characteristics of disc diffusion by comparing its results with those of the VITEK-2 COMPACT, considering the latter as the standard.
Methods: Disc diffusion was performed using Kirby-Bauer’s method on Mueller-Hinton agar with a HiMedia 15 mcg TGC disc, following FDA and EUCAST breakpoints. According to CLSI criteria, disc diffusion breakpoints can be considered acceptable when categorical agreement is ≥ 90%, the very major error is ≤ 1.5%, and the major error is ≤ 3%.
Results: Using Cohen’s kappa coefficient, the kappa value was 0.328, with a p-value of <0.05. The agreement percentage observed was 60.84%. Two strains reported as resistant by VITEK-2 COMPACT were misclassified as sensitive by disc diffusion, resulting in a very major error rate of 0.76%. A major error rate of 9.5% and a minor error rate of 27.7% were noted, as 25 strains reported as susceptible were identified as resistant.
Conclusion: Since poor agreement was observed, exceeding the acceptable performance rate, the disc diffusion method was unacceptable according to CLSI criteria. There is a gap in uniformity and a lack of streamlined, harmonized TST, which might become an alarming cause for concern.
 

Background: Antibiotic resistance in Helicobacter pylori infections can lead to treatment failure. This study aims to evaluate the antibiotic resistance to metronidazole, clarithromycin, and fluoroquinolone in H. pylori strains isolated from gastric biopsy specimens.
Methods: This study was conducted between 2016 and 2017 on 80 biopsy specimens obtained from Golestan province. Resistance to metronidazole (rdxA) and fluoroquinolones (gyrA) was determined using PCR. Mutations in the loci of the 23S rRNA gene associated with clarithromycin resistance were analyzed using PCR-RFLP with the BsaI and BbsI enzymes.
Results: In this study, 25% of H. pylori strains showed resistance to clarithromycin. Mutations in the A2143G locus (65%) and the A2142G locus (35%) were detected in these strains. Resistance to fluoroquinolones (27.5%) was observed, with the most common mutations being at the 91 amino acid position of aspartate (63.63%) and the 87 amino acid position of asparagine (36.36%). Resistance to metronidazole was not observed in any of the strains of this study, and concomitant resistance to clarithromycin and fluoroquinolones was observed in 13.75% of H. pylori strains.
Conclusion: According to our study, in Iran, the resistance of H. pylori to clarithromycin is increasing, which may lead to treatment failure. The mechanism of clarithromycin resistance is related to mutations in the A2143G and A2142G positions, and a mutation in the gyrA gene causes resistance to fluoroquinolones, which often occurs in the 91 amino acid position.
 

Background: The emergence of multidrug-resistant organisms has limited the choice of therapeutic options to treat infections. The lack of development of new antimicrobials paved the way for considering the reassessment of older antibiotics like fosfomycin. In this context, we assessed the in-vitro effect of fosfomycin against carbapenem-resistant Enterobacterales and methicillin-resistant Staphylococcus aureus (MRSA) bloodstream isolates by agar dilution, disk diffusion, and screen agar.
Methods: In this study, 141 consecutive blood isolates resistant to carbapenem and 62 MRSA blood culture isolates were collected over a period of 8 months. The methods used were fosfomycin agar dilution (0.25 µg/ml to 512 µg/ml), Kirby-Bauer disk diffusion (150 µg of fosfomycin + 50 µg of glucose-6-phosphate), and fosfomycin screen agar (32 µg/ml, 48 µg/ml, and 64 µg/ml). All three methods were interpreted using the European Committee on Antimicrobial Susceptibility Testing guidelines. The agreement between the new method and the reference method was calculated.
Results: Among the tested isolates, 100% of MRSA, followed by Escherichia coli (E. coli) (86.4%), Klebsiella pneumonia (K. pneumonia) (65.2%), and E. cloacae (50%) were susceptible to fosfomycin. The MIC50 and MIC90 of fosfomycin were 0.5 µg/ml and 2 µg/ml for MRSA, 16 µg/ml and 32 µg/ml for K. pneumoniae, 4 µg/ml and 16 µg/ml for E. coli, and 8 µg/ml and 32 µg/ml for E. cloacae, respectively.
Conclusion: Fosfomycin demonstrated a good in-vitro effect on most of the carbapenem-resistant Enterobacterales and MRSA isolates tested.