Showing papers in "Iranian journal of microbiology in 2015"

Nosocomial Infections: Multicenter surveillance of antimicrobial resistance profile of Staphylococcus aureus and Gram negative rods isolated from blood and other sterile body fluids in Iran.

Abstract: Background and Objective: Antibiotic resistance is increasing, especially in healthcare-associated infections causing significant public health concerns worldwide. National information is required to make appropriate policies, update list of essential drugs for treatment, and evaluate the effects of intervention strategies. A nationwide surveillance of antimicrobial resistant bacteria in nosocomial infections was established in Iran in 2008, so that the data obtained through the surveillance would enable us to construct a database. Materials and Methods: Seven major teaching hospitals in Shiraz, Tabriz, Sari, Mashhad, Sanandaj, Ahwaz and Isfahan participated in this study. A total of 858 strains isolated from blood and other sterile body fluids were tested. Identification at the species level was performed with conventional biochemical methods and the API system. Susceptibility tests were done using disk diffusion method. The methicillin-resistance in S. aureus (MRSA) was determined by the oxacillin agar screen plate and respective MIC values were assessed using the E-test strips. The confirmatory disk diffusion methods were applied for phenotypic identification of extended-spectrum β- lactamase (ESBL) production for E. coli and K. pneumoniae, according to CLSI guidelines. Results: Cultivation and re-identification of the strains yielded 858 isolates, consisting of 224 S. aureus, 148 Klebsiella spp., 105 Serratia spp., 146 E. coli, 67 Acinetobacter spp., 38 Enterobacter spp., 95 Pseudomonas spp., 71 P.aeruginosa. 35 Stenotrophomonas sp., and 8 other organisms. MRSA was detected in 37.5% of the isolates. No vancomycin-resistant or vancomycin-intermediate resistant S. aureus was detected. With the exception of Acinetobacter and Stenotrophomonas, 85% of the Gram-negative isolates were found to be susceptible in vitro to imipenem. Overall, about 61% of K. pneumoniae and 35% of E. coli isolates were ESBL producing. Conclusion: Multidrug resistant isolates of Gram-negative organisms and methicillin-resistant strains of S. aureus have been detected in many hospitals in this study.

Dissemination of carbapenemases producing Gram negative bacteria in the Middle East

Abstract: The emergence and spread of carbapenemase-producing bacteria, that hydolyze most β-lactams, including carbapenems, are a major concern of public health system worldwide, particularly in the Middle East area. Since the plasmids harboring resistance genes could be spread across other bacterial populations, detection of carbapenemase-producing organisms has become more problematic. These organisms produce different types of enzymes including the most prevalent types including KPC, VIM, IMP, NDM, and OXA-48. Carbapenemase producers are mostly identified among Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter baumannii. This study reviewed almost all papers, which conducted in the Middle East. In order to decrease the spread of resistance, the regional cooperation has been emphasized by the Middle East countries. The highest resistance, which is mediated by KPC has been observed in Afghanistan, Saudi Arabia and Jordan followed by NDM in Pakistan and OXA in Turkey and Pakistan. It is important to mention that the spread of these types have been reported sporadically in the other countries of this area. This review described the widespread carbapenemases in the Middle East area, which have been identified in an alarming rate.

Antimicrobial susceptibility pattern of Staphylococcus aureus isolated from clinical specimens in northern area of Jordan.

Abstract: Background and Objectives: The global spread of methicillin resistant Staphylococcus aureus (MRSA) constitutes one of the most serious contemporary challenges to the treatment of hospital-acquired infections. We aimed to screen and assess the antibiotic susceptibility pattern of Staphylococcus aureus isolated from clinical specimens in local hospitals of Northern province in Jordan. Materials and Methods: Staphylococcus aureus was isolated and identified using standard methods from various clinical specimens of different infected body sites from 358 patients during the period from January 2005 to November 2008. Results: Our analysis showed that 31.6% of S. aureus infections were MRSA, while 31% were multidrug resistance (MDR) and 42.7% were Oxacillin-resistant (ORSA). Most of these strains were isolated from wound specimens. All isolates were susceptible to vancomycin (100%). They were also susceptible to chloramphenicol, linezolid, nitrofurantoin, rifampicin and teicoplanin (>80%), but showed resistance to erythromycin and penicillin. Conclusion: Vancomycin was the most effective antimicrobial agent against S. aureus. We recommend regular surveillance of hospital associated infections and monitoring antibiotic sensitivity pattern and strict drug policy for antibiotics used within and outside the hospital environments.

Molecular detection of metallo-β-lactamase genes, bla IMP-1, bla VIM-2 and bla SPM-1 in imipenem resistant Pseudomonas aeruginosa isolated from clinical specimens in teaching hospitals of Ahvaz, Iran.

Abstract: Background and Objectives : Carbapenem resistant Pseudomonas aeruginosa is a serious cause of nosocomial infections.The main purpose of the study is to determine the prevalence rate of imipenem resistant Pseudomonas aeruginosa carrying metallo- beta- lactamase (MBL) genes. Material and Methods : 236 Pseudomonas aeruginosa isolates were collected from teaching hospitals of Ahvaz University of Medical Sciences during a period of 9 months in 2012. These strains were identified using conventional microbiological tests. The susceptibility of isolates to antibiotics were assessed using disk diffusion test. The IMP-EDTA combination disk phenotypic test was performed for detection of MBL producing strains. Finally, polymerase chain reaction (PCR) was performed to detect MBL genes, blaIMP-1, blaVIM-2 and blaSPM-1 in imipenem resistant strains. Results : Out of 236 examined isolates, 122 isolates (51.4%) were resistant to imipenem. The IMP-EDTA combination test showed that among 122 imipenem resistant strains, 110 strains (90%) were phenotipically MBL producers. Additionally, the results of PCR method showed that 2 strains (1.6%) and 67strains (55%) of imipenem resistant Pseudomonas aeruginosa isolates contained blaVIM-2 and blaIMP-1 genes respectively. No SPM-1gene was found in the examined samples. Conclusion : Resistance of P. aeruginosa isolates to imipenem due to MBL enzymes is increasing in Ahavaz. Because of clinical significance of this kind of resistance, rapid detection of MBL producing strains and followed by appropriate treatment is necessary to prevent the spreading of these organisms.

Detection of Salmonella spp in commercial eggs in Iran

Abstract: Background and Objective : Salmonellosis can be acquired through consumption of infected raw or undercooked eggs. The aim of this study was isolation and identification of Salmonella spp from the eggshells and the egg contents samples of Tabriz retails. Methods : A total number of 150 samples of eggs were analyzed for the presence of Salmonella spp. using conventional culture method and multiplex-PCR. Results : Two (1.33%) out of 150 samples from eggshells were determined as contaminated with Salmonella spp. Salmonella spp was not isolated from the egg contents. Salmonella serovar was determined as enteritidis and typhimurium. Conclusion : The results of the present study provide the recent dataset of the prevalence of S. enteritidis and S. typhimurium in eggs at retail shops in the northwest of Iran. It is important to remember that control is required at all levels in the food chain and by separating cooked and raw.

The antibacterial effect of sage extract (Salvia officinalis) mouthwash against Streptococcus mutans in dental plaque: a randomized clinical trial

Abstract: Background and Objective: The aim of the study was to evaluate the clinical effects of a mouthwash containing Sage (Salvia officinalis) extracts on Streptococcus mutans (SM) causing dental plaque in school-aged children. Material and Methods: A double blind clinical trial study was conducted in a dormitory on 70 girls aged 11-14 years having the same socioeconomic and oral hygiene conditions. These students were randomly divided into 2 groups; the first group (N=35) using Sage mouthwash, and the second group (N=35) using placebo mouthwash without active any ingredients. At the baseline, plaque samples obtained from the buccal surfaces of teeth were sent to laboratory to achieve SM colony count. These tests were reevaluated after 21 days of using the mouthwashes. Statistical data analysis was performed using t-student tests with p<0.05 as the level of significance. Results: Sage mouthwash significantly reduced the colony count (P=0.001). Average number of colonies in test group was 3900 per plaque sample at the baseline, and 300 after mouthwash application. In the control group, pre-test colony count was 4400 that was reduced to 4000; although this reduction wasn't significant. Conclusion: The Sage mouthwash effectively reduced the number of Streptococcus mutans in dental plaque.

Development of a loop-mediated isothermal amplification assay for rapid detection of Yersinia enterocolitica via targeting a conserved locus

Abstract: Background and Objectives: Loop-mediated isothermal amplification is a novel nucleic acid amplification assay providing as a simple diagnostic tool for rapid identification of microbial diseases in developing countries. In this study, a LAMP assay was established for Yersinia enterocolitica, a leading cause of acute enterocolitis in young children. Materials and Methods: LAMP assay was established with four primers targeting a specific locus for the detection of Y. enterocolitica. The assay was conducted at 65°C in thermo block for 90min. The sensitivity of LAMP was evaluated in com- parison to conventional PCR using pTZ57R containing the target locus. Finally, specificity was assessed using DNA from common enteropathogenic bacteria. Results: Results showed that the sensitivity of LAMP assay was 44-copy number, which was 10-fold higher than that of PCR. No cross-reactivity was observed when testing against other enteropathogenic pathogens. Conclusion: This study showed that LAMP assay is an alternative molecular diagnostic tool for infections with Y. enteroco- litica. In addition, this method may be useful in diagnosis at field or in laboratories without PCR machine.

Prevalence and antimicrobial susceptibility pattern of coagulase-negative staphylococci (CoNS) isolated from clinical specimens in Northern of Jordan

Abstract: Background: Coagulase negative Staphylococci (CoNS) are one of the most common bacteria found on human skin and on mucous membranes as a component of normal flora. The presence of CoNS in clinical specimens is frequently associated with an infectious aetiology or contamination. Objectives: We aimed to evaluate CoNS species distribution and susceptibility patterns in specimens obtained from clinics and hospitals in the Northern area of Jordan. Methods: Standard identification methods showed the presence of CoNS in 223 specimens at different local hospitals. Susceptibility testing was performed using 18 antibiotics in accordance with the Clinical and Laboratory Standards Institute (CLSI) recommendations. Results: Staphylococcus epidermidis and S. haemolyticus were found to be the most common species isolated from all spec- imens representing 122 (54.7%) and 52 (23.4%) of all CoNS species, respectively. Antibiotic susceptibility testing of CoNS species revealed their sensitivity to vancomycin, linozolid, rifampin and nitrofurantin, while showing a highly resistant pattern to ampicillin, penicillin, ceftriaxone, cefazolin, amoxicillin-clavulanic acid and erythromycin. Some variation of the susceptibility pattern of CoNS species were identified in specimens isolated from the ICU and paediatric hospital wards as well as from clinical specimens of urine, blood and catheter tips. Conclusion: The most common CoNS isolates were found to be S. epidermidis and S. haemolyticus with variable percentag- es according to the specimen source. Moreover, a high susceptibility CoNS to vancomycin, rifampin, and linezolid showed resistance to amoxicillin and penicillin.

Detection of mecA and enterotoxin genes in Staphylococcus aureus isolates associated with bovine mastitis and characterization of Staphylococcal cassette chromosome mec (SCCmec) in MRSA strains

Abstract: Background and Objectives: Staphylococcus aureus is one of the main causatives of bovine mastitis. Resistance of some strains to methicillin, can complicate the treatment of its infections. On the other hand, enterotoxin production is also im- portant. Therefore, the aim of our study was to investigate the methicillin resistance and enterotoxin production in S. aureus isolates caused bovine mastitis. Materials and Methods: Four hundred and fifty milk samples were collected. After isolation of Staphylococcus aureus , MRSA strains were detected by cefoxitin disc diffusion and oxacillin agar screening methods. DNA was extracted by phenol – chloroform method and PCR was applied for mec A, sea and seb genes. SCCmec types of mec A gene were identified using multiplex-PCR. Results: Fifty-four (12%) S. aureus were isolated. Out of these, 10 and 9 MRSA strains identified by cefoxitin disc diffusion and oxacillin agar screening methods, respectively. All 10 MRSA isolates identified by cefoxitin disc diffusion, were positive for mec A gene and all of them belonged to SCCmec type IV. The sea genes were detected in 19 isolates and only two isolates were positive for seb genes. One isolate possessed both sea and seb genes. Conclusion: Findings of this study indicated that results of cefoxitin disc diffusion test is in concordance with the PCR for mec A gene and has a higher sensitivity compared to oxacillin agar screening method. Finally, Our findings suggest that enterotoxin A is the dominant type.

Extended-spectrum β-lactamase and carbapenemase production among burn and non-burn clinical isolates of Klebsiella pneumoniae.

Abstract: Background and Objectives: Klebsiella pneumoniae is an opportunistic pathogen responsible for up to 10% of nosocomial infections. The emergence and spread of multidrug resistant K. pneumoniae, mostly due to the production of extended-spec- trum β-lactamases (ESBL) and carbapenemases, is often responsible for antibiotic treatment failure of these infections. We compared the antibiotic resistance profiles, ESBL and carbapenemase production as well as presence of KPC-type genes in burn and non-burn clinical isolates of K. pneumoniae. Materials and Methods: Fifty five clinical isolates were collected from Shahid Motahari (25 burn isolates) and Shariati (30 non-burn isolates) hospitals between August 2011 to January 2012. Antibiotic susceptibility was determined to 12 antibiot- ics using disc diffusion. The phenotypic confirmatory test (PCT) was used to screen for ESBL production. Carbapenemase activity was measured by the modified Hodge test (MHT) and KPC-type carbapenemases were further sought by PCR using specific primers. Results: Both groups were highly resistant to cefotaxime and ceftazidime (>92%). Burn isolates were significantly more resistant to cefepime, amoxiclav, imipenem, meropenem, gentamicin and ciprofloxacin compared to the non-burn strains (p<0.05). No significant differences were observed in ESBL production between the two groups. Carbapenem resistance was only observed among the burn isolates (n=5, 9.1%). Five carbapenem-resistant isolates produced carbapenemases. However, none of the isolates harbored the KPC-type genes. Conclusion: Higher rates of drug resistance were observed in burn isolates of K. pneumoniae compared to the non-burn strains. Carbapenemase phenotype was only observed among the burn isolates but KPC-type gene was not detected.

Evaluation of nested PCR in diagnosis of fungal rhinosinusitis

Abstract: Background and Objective: Given the importance of rapid diagnosis for fungal rhinosinusitis, this study aimed to evaluate the use of nested PCR to identify Aspergillus and Mucor species in clinical samples from patients with suspected fungal rhinosinusitis. Methods: Functional endoscopic sinus surgery specimens were collected from 98 patients with rhinosinusitis from 2012 to 2013. All samples were ground and cultured on sabouraud dextrose agar. The isolated fungi were identified based on their macroscopic and microscopic features. Fungal DNA was extracted from the tissue samples and nested PCR was performed with two sets of primers for Mucor and Aspergillus. Results: Direct microscopic showed that 5.1% contained fungal components and 9.2% exhibited growth of fungi in culture. The most common agents isolated were Aspergillus fumigatus (n= 3 ), Aspergillus flavus (n=2), Penicillium sp (n=3) and Alternaria sp. (n=1). Mucor sp. was identified in the pathology smear from 1 patient. Positive results for fungal rhinosinusitis were obtained for a total of 10.2% by culture or pathology smear. Positive PCR results were obtained in 72 samples for Aspergillus and 31 samples for Mucor. Conclusion: Our results suggest that endoscopic sinus surgery specimens are not suitable for nested PCR, probably because of the accumulation of fungi that contaminate the environmental air. This drawback is a limiting factor for diagnosis with nasal cavity specimens. Therefore, molecular methods and conventional culture techniques are helpful complementary diagnostic methods to detect fungal rhinosinusitis and determine appropriate management for these patients.

Hepatitis E virus seroprevalence in HIV positive individuals in Shiraz, Southern Iran.

Abstract: Background and Objectives : Hepatitis E virus (HEV) is the most common cause of acute viral hepatitis in the world. It is usually a self-limited disease but may leads to the deaths of about 20% of pregnant women in developing countries. This study was conducted to determine the prevalence of HEV infection among HIV individuals. Materials and Methods : This is a cross-sectional survey of HIV positive individuals in voluntary counselling and testing center of Shiraz in 2013 . Using the systematic random sampling method, 158 patients enrolled for the research. They were asked about their age, gender, area of residence, marital status, number of children, education level, occupation, history of imprisonment, mode of HIV transmission, and viral hepatitis co-infection .Three ml venous blood sample was drawn from each subject and transferred to the laboratory of voluntary counselling and testing center. Results : The overall seroprevalence of hepatitis E was 26 (16.4%), where it increased significantly with age ranging from zero in subjects less than 30 years of age to 47.4% in those aged 50 years or older. Conclusion : Co-infection of HIV positive individuals with HEV is an issue that should be of concern to health care providers.

Evaluation of anti-bacterial effects of some novel thiazole and imidazole derivatives against some pathogenic bacteria

Abstract: Background and Objectives: Bacterial resistance to antibiotics has motivated the researchers to evaluate the novel anti-bac- terial compounds such as some thiazole and imidazole derivatives. Thereby, in this work, we investigated the anti-bacterial effects of one new thiazole and two new imidazole derivatives on Bacillus cereus , Listeria monocytogenes , Escherichia coli, Salmonella typhimurium , Proteus mirabilis and Shigella dysenteriae. Materials and Methods: The thiazole and imidazole derivatives were dissolved in DMSO. The disk diffusion method was utilized to measure the growth inhibition zone diameter values, and the broth micro-dilution method was applied to deter- mine the minimum inhibitory concentration (MIC) values. Results: The synthesized imidazole derivatives lacked any inhibitory effect against the tested bacteria. On the other hand, although the synthesized thiazole derivative showed no inhibitory effect against Bacillus cereus, Salmonella typhimurium, and Escherichia coli, it inhibited the growth of Proteus mirabilis, Shigella dysenteriae, and Listeria monocytogenes with the MIC values of 1000, 125, and 1000 µg/ml, respectively, and the growth inhibition zone diameter values of 9.3 ± 0.1, 15.6 ± 0.2, and 8.1 ± 0.0 mm, respectively. Conclusion: The anti-bacterial effect of the synthesized thiazole derivative on Shigella dysenteriae, Proteus mirabilis and Listeria monocytogenes was proven. However, its inhibition effect against Shigella dysenteriae was more than that against the others. Many in-vitro and in-vivo experiments are required to evaluate the effects of this compound on the bacteria and the human body.

Dissemination of Pseudomonas aeruginosa producing blaIMP-1 and blaVIM-1 in Qazvin and Alborz educational hospitals, Iran

Abstract: Background and Objectives: Pseudomonas aeruginosa is a frequent opportunistic pathogen in health care associated infections that is highly resistant to the majority of β-lactams. The aims of this study were to access the antimicrobial susceptibility pattern of P. aeruginosa isolated from educational hospitals of Qazvin and Alborz provinces, to determine the prevalence of metallo-β-lactamase (MBL) among carbapenem non-susceptible isolates by combined disk (CD) method, and to detect the bla IMP, bla VIM, bla SIM, bla GIM, bla SPM and bla NDM-1-MBL genes. Materials and Methods: In this cross-sectional study, 300 P. aeruginosa isolates were collected from different clinical specimens in two provinces of Qazvin and Alborz hospitals, Iran. After identification of isolates by standard laboratory methods, antimicrobial susceptibility was done against 17 antibiotics according to clinical and laboratory standards institute (CLSI) guideline. CD method was carried out for detection of MBLs and the presence of bla IMP, bla VIM, bla SIM, bla GIM, bla NDM-1 and bla SPM-genes was further assessed by PCR and sequencing methods. Results: In this study, 107 (35.66%) isolates were non-susceptible to imipenem and/or meropenem among those 56 (52.3%) isolates were metallo-β-lactamase producer. Twenty-four of 56 (42.85%) MBL-positive isolates were confirmed to be positive for MBL-encoding genes in which 14 (25%) and 10 (17.85%) isolates carried bla IMP-1 and bla VIM-1 genes either alone or in combination. Three (5.35%) isolates carried bla IMP and bla VIM genes, simultaneously. Conclusion: Considering the moderate prevalence and clinical importance of MBL-producing isolates, rapid identification and use of appropriate infection control (IC) measures are necessary to prevent further spread of infections by these resistant organisms.

Molecular, chemical and biological screening of soil actinomycete isolates in seeking bioactive peptide metabolites.

Abstract: Background and Objective: Due to the evolution of multidrug-resistant strains, screening of natural resources, especially actinomycetes, for new therapeutic agents discovery has become the interests of researchers. In this study, molecular, chemical and biological screening of soil actinomycetes was carried out in order to search for peptide-producing actinomycetes. Materials and Methods: 60 actinomycetes were isolated from soils of Iran. The isolates were subjected to molecular screening for detection NRPS (non-ribosomal peptide synthetases) gene. Phylogenic identification of NRPS containing isolates was performed. Chemical screening of the crude extracts was performed using chlorine o-dianisidine as peptide detector reagent and bioactivity of peptide producing strains was determined by antimicrobial bioassay. High pressure liquid chromatography- mass spectrometry (HPLC-MS) with UV-visible spectroscopy was performed for detection of the metabolite diversity in selected strain. Results: Amplified NRPS adenylation gene (700 bp) was detected among 30 strains. Phylogenic identification of these isolates showed presence of rare actinomycetes genera among the isolates and 10 out of 30 strains were subjected to chemical screening. Nocardia sp. UTMC 751 showed antimicrobial activity against bacterial and fungal test pathogens. HPLC-MS and UV-visible spectroscopy results from the crude extract showed that this strain has probably the ability to produce new metabolites. Conclusion: By application of a combined approach, including molecular, chemical and bioactivity analysis, a promising strain of Nocardia sp. UTMC 751 was obtained. This strain had significant activity against Staphylococcus aureus and Pseudomonas aeruginosa. Strain Nocardia sp. UTMC 751 produce five unknown and most probably new metabolites with molecular weights of 274.2, 390.3, 415.3, 598.4 and 772.5. This strain had showed 99% similarity to Nocardia ignorata DSM 44496 T .

Microencapsulation of Saccharomyces cerevisiae and its evaluation to protect in simulated gastric conditions.

Abstract: Background and Objectives: Probiotic yeasts are used in production of functional foods and pharmaceutical products. They play an important role in promoting and maintaining human health. Until now, little work has been published on improving the survival of Saccharomyces in stimulated gastrointestinal condition. Material and Methods: In this study the exposure of the yeast in the capsulate and free forms to artificial gastrointestinal conditions was assessed and the number of viable Saccharomyces cerevisiae cells during 0 to 120 mines in these conditions was evaluated by a pour plate method using sabouraud dextrose agar. Results: Results showed the shape of the beads was generally spherical, sometimes elliptical with a mean diameter of about 50–90 µm. Also count of viable probiotic cells obtained for all the microcapsules were above the recommended levels for a probiotic food. Also decrease of approximately 4 logs was noted in the number of free cells after 2 h of incubation at pH 2 and 8, when compared to decreases of about 2 logs in the all microencapsulated S. cerevisiae under similar conditions. Conclusion: It is concluded that microencapsulation process was significantly able to increase the survival rate of Saccha- romyces in a simulated gastrointestinal condition (p<0.05)

Methicillin Resistant Staphylococci: Prevalence and susceptibility patterns in a burn center in Ahvaz from 2013-2014

Abstract: Background and Objectives: Methicillin resistance Staphylococcus aureus (MRSA) and coagulase negative staphylococci (MRCoNS) have recognized as the major cause of nosocomial infections that threat the burn patient’s life. The aims of this study were to determine the frequency of MRSA and MRCoNS and their antibiotic resistance patterns among burn patients in a burn center in Ahvaz, Iran. Material and Methods: A total of 340 clinical specimens: (80%) wound and (20%) blood were obtained from patients in Taleghani burn hospital during February 2013-2014. Staphylococci species identification and antibiogram were performed by standard procedures using disk diffusion method. The Methicillin resistance strains were detected by Etest and PCR using mec A specific primers. Results: Out of 30.2% (103) isolates that were recognized as staphylococci, 82 % (84) and 18% (19) were identified as S. aureus and coagulase negative staphylococci (CoNS) respectively. Resistance to methicillin was detected in 60% and 63% of the S. aureus and CoNS isolates respectively. Seven different antimicrobial resistance patterns observed among methicillin resistant staphylococci. The MRSA and MRCoNS strains showed closed resistance phenotypes. All the methicillin resistant isolates showed a high rate resistance to the other studied antibiotics in comparison to methicilin sensitive isolates. Vancomy- cin and imipenem showed the greatest effect against methicillin resistant isolates. During 8 years in the studied burn hospital, no significant changes in the methicillin resistance staphylococci frequency were detected. Conclusion: The presence of multi resistant MRSA and MRCoNS strains is cause of concern in burn hospitals. Vancomycin remains as a drug of choice for methicillin resistance staphylococci infections.

Nosocomial emerging of (VIM1) carbapenemase-producing isolates of Klebsiella pneumoniae in North of Iran.

Abstract: Background and Objectives : The rapid emergence and dissemination of carbapenemase-producing Klebsiella pneumoniae strains and other members of the Enterobacteriaceae poses a considerable threat to the care of hospitalized patients and to public health. The aim of this study was to determine the frequency of metallo-β-lactamases (MBL) and VIM-1 gene in multidrug-resistant strains of K. pneumoniae. Methods : 50 isolates of non – duplicated K. pneumoniae cultured from patients at intensive care units were tested for their susceptibilities to 13 different antibiotics using microbroth dilution assay. Isolates showing resistance to at least one of the carbapenems were checked for production of metallo-β-lactamase (MBLs) using imipenem–EDTA synergy tests. PCR was used to detect the gene encoding VIM-1 metallo-β-lactamase (MBL). Results : Of 50 clinical isolates, 26 (52%) were resistant to imipenem in disk diffusion method. Using imipenem–EDTA synergy tests, production of MBL was detected in 15 (30%) isolates. PCR assay showed that 15 isolates were positive for VIM and these included 10 and 5 isolates showing positive and negative results in phenotypic method of MBL detection test respectively. Amikacin was found as the most effective antibiotic against the MBL producers in this study. Conclusion : The emergence of bla(VIM-1) producing K. pneumoniae in North of Iran is concerning. Microorganisms producing bla(VIM-1) constitute the prevalent multidrug-resistant population of K. pneumoniae in that region.

Comparison of antifungal activities of various essential oils on the Phytophthora drechsleri, the causal agent of fruit decay.

Abstract: The efficacy of Mentha piperita L, Zataria multiflora Boiss and Thymus vulgaris L essential oils (EOs) was evaluated for controlling the growth of Phytophthora drechsleri, the causative agent of damage to many crops that is consumed directly by humans.The EOs used in this study was purchased from Magnolia Co, Iran. The pour plate method in petri dishes containing Potato Dextrose Agar (PDA) was used to evaluate the antifungal properties of EOs. The minimal inhibitory concentrations (MIC), minimum fungicidal concentration (MFC) as well as mycelial growth inhibition (MGI) were measured. The IC50 value (the concentration inhibited 50% of the mycelium growth) was calculated by probit analysis.The fungal growth was significantly reduced by increasing concentrations of tested EOs. The complete reduction was obtained with Shirazi thyme at all concentrations, whereas the complete reduction for peppermint and thyme was observed at 0.4% and 0.8% (v/v) concentrations, respectively. Meanwhile, the minimum inhibition was observed when 0.1% peppermint (MGI values of 9.37%) was used. The IC50, MIC and MFC values of Shirazi thyme was 0.053, 0.1% and 0.2%, respectively. Similarly, MIC and MFC values of peppermint and thyme were recorded 0.4% and 0.8%, respectively. The results obtained from this study may contribute to the development of new antifungal agents to protect the crops from this pathogenic fungus and many agricultural plant pathogens causing drastic crop losses.

Detection of blaPER-1 & blaOxa10 among imipenem resistant isolates of Pseudomonas aeruginosa isolated from burn patients hospitalized in Shiraz Burn Hospital.

Abstract: Pseudomonas aeruginosa is one of the most important Gram negative opportunistic bacteria which causes infection among burn patients. Resistance to the antibiotics in this group of bacteria is increased due to the activity of extended spectrum β-lactamase (ESBLs) genes. In the current study, we investigated the prevalence of two genes (blaPER-1 & blaOxa10 ) related β-lactamase genes among imipenem resistance clinical isolates of P. aeruginosa in hospitalized patients.From May 2010 to March 2011, 270 P. aeruginosa isolated from hospitalized burned patients' wounds in Shiraz Burn Hospital, were tested for Imipenem resistance by disk diffusion method. Presence of ESBLs exo-enzyme, blaPER-1 and blaOxa10 genes were also evaluated in the resistant isolate.210 (77.7%) of 270 P. aeruginosa isolates were resistant to imipenem. blaPER-1 and blaOxa10 were detected among 168 (80.0%) of imipenem resistant isolates. Furthermore, 160 (76.2%) of them had blaOxa10 gene and 84 (40.0%) of them had blaPER-1 while 63 (30.0%) resistant isolates contained both genes simultaneously.This study showed a high prevalence of blaPER-1 and blaOxa10 genes in hospitalized burn patients in south west of Iran. Therefore, it's highly recommended to perform such tests routinely to evaluate the resistance pattern in order to better antibiotic selection in the burned patients.

Enterobacterial repetitive intergenic consensus (ERIC) PCR based genetic diversity of Xanthomonas spp. and its relation to xanthan production

Abstract: Background and Objective : The genus Xanthomonas is composed of phytopathogenic bacterial species. In addition to causing crops diseases, most of the Xanthomonas species especially Xanthomonas campestris produce xanthan gum via an aerobic fermentation process. Xanthan gum is, an important exopolysaccharide from Xanthomonas campestris, mainly used in the food, petroleum and other industries. the purpose of this study was assessment of relationship between genetic diversity and xanthan production in Xanthomonas spp. Materials and Methods : In this study 15 strains of Xanthomonas spp. which had previously been isolated from soils of vegetable farms, were discriminated from each other using Enterobacterial Repetitive Intergenic Consensus (ERIC) PCR and 16S rDNA sequencing methods. Xanthan production of strains was measured in 250 ml flask. The results of ERIC PCR and xanthan production was compared. Results : ERIC-PCR patterns not only could differentiate all Xanthomonas campestis from the control i.e. Xanthomonas translucent but also discriminate strains of Xanthomonas to three clusters with 40% similarity based on Jaccard’s coefficient. This clustering of the strains was in agreement with other characteristics including xanthan production and biochemical features. Discussion : The results showed that genomic fingerprinting conferred adequate genetic data for discriminating between strains of the species Xanthomonas campestris. The data indicated a partial relationship between ERIC-PCR patterns and xanthan production by the strains. Conclusion : Further development of experiments may result in making good prediction about xanthan production capability of the Xanthomonas strains on the basis of ERIC-PCR method.

Frequency of methicillin-resistant Staphylococcus aureus nasal carriage in healthy children

Abstract: Background and Objective : The prevalence of community acquired methicillin resistant Staphylococcus aureus (CA-MRSA) is increasing around the world. It involves healthy people and causes a variety of diseases. Material and Methods : This cross sectional study was conducted from September 2010 - June 2011 on children less than 14 years of Ahvaz, southwest Iran. The participants were selected with two staged cluster sampling. A sterile cotton nasal swab was used to collect the samples from the 864 participants. MRSA isolates were identifed by catalase and coagulase tests and 1 μg oxacillin disk method. Polymerase chain reaction (PCR) was performed on all the MRSA colonies to detect the mecA gene. Data was put in SPSS 16 software and descriptive statistics and chi-square test were used for analysis. Results : Out of 864 children, 471(54.51%) were male and 393 (45.49%) were female. 235 children (27.1%) had Staphylococcus aureus and 11 (1.3%) of all children diagnosed with MRSA. PCR showed that 7 colonies (0.8%) had the mecA gene. Conclusion : The results of this study indicate that MRSA exists in healthy children of Ahvaz. Although the prevalence of CA-MRSA is lower than many other regions, it still needs close attention to prevent its transmission. Further studies are needed to identify the risk factors of CA-MRSA.

Study on imipenem resistance and prevalence of blaVIM1 and blaVIM2 metallo-beta lactamases among clinical isolates of Pseudomonas aeruginosa from Mashhad, Northeast of Iran

Abstract: Background and Objectives : The main cause of serious nosocomial infections is a Gram-negative pathogen known as Pseudomonas aeruginosa (P. aeruginosa). Carbapenems are widely used as an appropriate treatment for these infections, however resistance to these agents has been observed and is increasing. Metallo beta-lactamase (MBLs) enzyme is one of the main causes of resistance to carbapenem. In the current study the frequency and production of VIM1 and VIM2 by imipenem-resistant P. aeruginosa isolates of patients hospitalized in Imam Reza hospital were evaluated. Materials and Methods : In this study, 131 clinical samples were collected from patients hospitalized in Imam Reza hospital in Mashhad during a 15-month period from May 2011 to November 2012. After verification of P. aeruginosa isolates, antibiotic resistance patterns of isolates were determined for 14 antibiotics by Kirby-Bauer standard disk diffusion according to the CLSI guidelines. Combined-disk test was used for phenotypic determination of MBLs-producing isolates and after DNA extraction, genotypic determination of VIM1 and VIM2 metallo beta-lactamase genes was carried out using Multiplex- PCR. Results : Of 63 imipenem-resistant isolates (48.5%), 56 (88.8%) were MBL-producing in phenotypic assessments. Also amongst imipenem-resistant isolates, the frequency of VIM1 and VIM2 genes were 58.7 and 3.17%, respectively. Conclusion : The results of the current study along with the results of the other conducted studies in Iran in recent years demonstrate that the average resistance to imipenem in P. aeruginosa isolates was 51.3% which has increased in comparison with the results in 2006 (32.9%). It was also determined that the frequency of VIM1 gene was more than VIM2 gene. In phenotypic assessment by using CD method, 49.6% of isolates were determined as MBLs-producing. The sensitivity and specificity of this method were verified in comparison with the results of PCR test.

Detection of Chlamydophila psittaci from pigeons by polymerase chain reaction in Ahvaz.

Abstract: Background and Objective : Chlamydophila psittaci is a lethal bacterium that causes endemic avian chlamydiosis, and respiratory psittacosis. Laboratory diagnosis of Chlamydophila psittaci is difficult by culture. This study was design to investigate the presence of Chlamydophila psittaci in collected pharyngeal swabs from asyptomatic pigeons by PCR. Materials and Methods : Pharyngeal samples from pigeons with no symptoms of disease (n=280) were collected during hot and cold seasons in different parts of Ahvaz. DNA was extracted from specimens and subjected to PCR targeting pmp genes and 16s-23s rRNA intergenic spacer of Cp. psittaci and chlamydiales specific primers. Results : Of 280 samples 2 (0.7%) harbor were positive for chlamydiales (16s-23s intergenic spacer) and Cp. psittaci specific genes (pmp gene). Conclusions : In this research the pigeons were asymptomatic carriers for Cp. psittaci in their respiratory discharges. These results suggest that Cp. psittaci infection of human can occur in very close and continuous contact with pigeons.

Distribution of Shiga toxin genes subtypes in B1 phylotypes of Escherichia coli isolated from calves suffering from diarrhea in Tehran suburb using DNA oligonucleotide arrays

Abstract: Background and Objectives: Shiga toxin-producing Escherichia coli (STEC) have emerged as human pathogens and con- tamination via animal origin has been a major public health concern. We compared the distribution of phylogenetic groups and prevalence of stx gene variants among the pathogenic strains of Escherichia coli isolated from feces of diarrheatic calves in Tehran suburb farms. Materials and Methods: In this study we screened 140 diarrheatic calves (1-15 days old) for E. coli strains during a 3 months period of time. The isolated strains were grouped into different phylotypes according to the presence of chuA, yjaA and TSPE4.C2 genes. Then, the prevalence of stx gene subtypes was evaluated in the B 1 phylotypes. Results: From diarrheatic calves, 51 bacterial isolates were biochemically identified as E. coli and 31 isolates out of 51 were considered B 1 phylotype using DNA Microarray technology. Of these isolates, 20 contained stx 1 a and stx 1 b and one harbored all mentioned variants of stx genes except stx 2 b 2 . Conclusion: This study showed that in Tehran suburb, the B 1 phylotype of E. coli is prevalent as a causative agent of diarrhea in calves and the prevalence of stx 1 gene subtypes is dominant in comparison with other subtypes. Considering the possibility that these stx genes can be spread to other strains, bovine E. coli strains are an important source of stx genes for other strains and further study and surveillance seems to be required for the exact identification of virulence profile of E. coli phylotypes in different hosts.

Clinico-microbiological study of candidemia in a tertiary care hospital of southern part of India

Abstract: Background and objectives : Over the last two decades, both the incidence of nosocomial candidaemia and the proportion of blood stream infection due to Candida spp. other than Candida albicans have increased. The aims of this study was to identify different species of Candida and risk factors associated with bloodstream infection and detection of biofilm production. Materials and methods : This study was conducted in an 840 bedded tertiary care hospital, over a period of one year. All blood isolates received from patients during this period were screened for candidemia prospectively. Speciation was carried out by standard microbiological method. Biofilm production detection was done by Brachini et al method. Result : A total of 80 cases of candidemia were identified. Most important risk factor was placement of vascular access devices in all the age groups. Candida albicans accounted for 22 isolates (27.5%) whereas non-albicans Candida spp. accounted for 58 isolates (72.5%). Biofilm production was found in 31 strains (38.75%). Biofilm production was seen more in non-albicans Candidaspp. (83.87%) especially in C. tropicalis (66.67%, 8 of 12). Conclusions : Non-albicansspecies of Candida were most frequently recovered in our study. So, the epidemiology of Candida infection is changing. Non–albicans Candida spp have the capacity to produce significant amount of biofilm which may be the cause of their reduced susceptibility to antifungal agents.

Genotyping of Mycobacterium avium subsp. avium isolates from naturally infected lofts of domestic pigeons in Ahvaz by IS901 RFLP.

Abstract: Background and Objectives: Avian tuberculosis is one of the most important infections affecting most species of birds. Mycobacterium avium can not only infect all species of birds, but also infect some domesticated mammals.The most crucial aspect of control and eradication scheme is identification of infection sources and transmission routs. Mo- lecular techniques such as restriction fragment length polymorphism and pulse field gel electrophoresis have been shown to be much more discriminatory and suitable for use in the epidemiological study. Materials and Methods: Eighty suspected pigeons to avian tuberculosis based on their clinical signs, were subjected to the study. Forty Mycobacterium avium subsp. avium isolates out of a total of 51 identified isolates were subjected to the test. Results: IS901 -RFLP using Pvu II was successfully conducted and produced 7 patterns. The majority of isolates (60%) were RFLP type PI.1. This type was the most similar type to standard strain. However, all the patterns obtained in this study were different from the standard strain. Conclusion: The result of this study indicate that these isolates probably are limited to Khuzestan region. We recommend DNA fingerprinting differentiation of non tuberculous Mycobacteria particularly Mycobacterium avium complex isolated from infected birds and human to possibly find source of infections.

Comamonas sp. halotolerant bacterium from industrial zone of Jovein of Sabzevar introduced as good candidate to remove industrial pollution

Abstract: Background and Objectives: Heavy metals are considered as high risk biocides due to their harmful effects on human health, the environment and other living organisms. Bacterial strains showing resistance to heavy metals has been used for removing such toxic materials from the environment. In this study we isolated and characterized a heavy metals-resistance halophilic bacterial strains from Kal shoor Jovein of Sabzevar, one of the industrial zone of Khorasan-e- Razavi province in Iran and has naturally saline oils. Materials and Methods: Strain JC-66 is heavy metals-resistance halophilic bacterial strains isolated from Kal shoor Jovein of Sabzevar. The 16S rDNA gene was sequenced to identify this bacterium. The appropriate conditions for its potency to remove the lead were tested in various temprature, pH and agitation speed. The resistance mechanism of JC-66 to lead were investigated. Results: JC-66 is a Comamonas sp. according to 16S rDNA sequence analysis. Based on minimum inhibitory concentration (MIC) results, the isolated strain has high resistance to the lead metal. The optimal condition for lead removal was exhibited in neutral medium (pH 7) incubation temperature 37 °C, and shaking rate of 180 rpm for JC-66. X-Ray Diffraction results also are indicative of adsorption mechanism to lead metal uptake. Plasmid extraction was performed to confirm the role of plasmids in bacterial resistance to lead. Conclusion: It can be concluded that the mechanism of resistance to heavy metals in the studied strain, is the result of an expression plasmid, and adsorption. It was concluded that JC-66 is able to be one of the best candidates to remove industrial pollution because it showed high resistance to lead.

ISPpu22, a novel insertion sequence in the oprD porin gene of a carbapenem-resistant Pseudomonas aeruginosa isolate from a burn patient in Tehran, Iran.

Abstract: Background and Objectives: The oprD mutation and AmpC overproduction are the main mechanisms of intrinsic resistance to carbapenems such as imipenem and meropenem in Pseudomonas aeruginosa . Materials and Methods: In this study, we investigated intrinsic resistance to carbapenems including mutation of oprD and AmpC overproduction in a carbapenem-resistant P. aeruginosa isolated from a burn patient by phenotypic and molecular methods. Results: In our study, the carbapenem-resistant P. aeruginosa isolate was resistant to imipenem, meropenem, cefepime, gentamicin, ceftriaxone, carbenicillin, aztreonam and ciprofloxacin but was susceptible to ceftazidime and polymyxin B. The minimum inhibitory concentrations (MICs) against imipenem, meropenem and ceftazidime were 64 μg/ml, 16 μg/ml and 2μg/ml, respectively. The isolate was ESBLs and AmpC overproducer. No carbapenemase activity was detected by Modified Hodge test (MHT). This isolate was carrying only bla OXA-10 . PCR amplification and sequencing of oprD performed on isolate resulted in PCR product of 2647bp. Sequence analysis of the 2647bp product revealed insertion of a sequence of 1232 bp at position 8 in coding region of oprD. Conclusion: According to the results of this study, oprD mutation and AmpC overproduction can cause the main mechanism of resistance of P. aeruginosa to carbapenems.

Genotyping of Haemophilus influenzae type b strains and their incidence in the clinical samples isolated from Iranian patients.

Abstract: Background and Objective: Haemophilus influenzae type b (Hib) is divided into two distinct genotypes, type I and type II, based on the structure of capsular polysaccharides. The capsulation locus of Haemophilus influenzae type b consists of three functionally distinct regions, designated regions 1 to 3. Region III contains hcsA and hcsB genes; however, notable sequence variation in this region can be used to recognize different Hib genotypes. The purpose of this study was to investigate the prevalence and genotype of the Hib strains isolated from patients with invasive disease in Iran. Materials and Methods: In the present study, 8 pairs of primers were used for identification and serotyping of encapsulated Haemophilus influenzae strains, as well as confirmation of species identification. Additionally, in order to identify the cap- sular genotypes of Haemophilus influenzae type b (type I and II), two additional primer pairs were used to amplify the hcsA gene. Results: Out of 50 isolates of H. influenzae, four were found to be type b. Interestingly, among these 4 Hib isolates, 2 strains belonged to the type-II category. Conclusion: Our study shows that the prevalence of both Hib types I and II seems to be high in Iran.