فهرست مطالب

Microbiology - Volume:9 Issue: 5, 2017
  • Volume:9 Issue: 5, 2017
  • تاریخ انتشار: 1396/09/28
  • تعداد عناوین: 8
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  • Kanne Padmaja, Sukanya Sudhaharan, Lakshmi Vemu, Oruganti Sai Satish, Padmasri Chavali, Mamidi Neeraja Pages 257-263
    Background And Objectives
    Infective endocarditis (IE) is a microbial infection of the endothelial surface of the cardiacvalves. Rapid diagnosis, effective treatment and prompt recognition of complications are essential, in order to improve the outcome. We retrospectively reviewed and determined the clinical characteristics, microbiological profile and management strategies of IE cases, changing microbial spectrum of pathogens and outcome in Native Valve Endocarditis (NVE) and Prosthetic Valve Endocarditis (PVE) cases.
    Materials And Methods
    We retrospectively reviewed the medical records of 191 patients, clinically diagnosed with IE, based on modified Dukes criteria, from January 2011 to December 2016. Blood cultures received from all these patients were processed, using BacT/Alert system (bioMerieux, Marcy lEtoile, France).
    Results
    Sixty eight (68/191) cases were positive for bacterial pathogens. Twenty four (24/191) cases had PVE and 167/191 had NVE. Nineteen cases (19/24, 79.1%) were PVE positive and forty nine (49/167, 29.3%) were NVE positive. Culture negative endocarditis cases were 123/191 (64.39%). The most common pathogen isolated from NVE cases, in our study was Streptococcus mitis, followed by methicillin-resistant coagulase negative staphylococcus (MRCONS) in PVE. The NVE were treated intravenously with a combination of a β-lactam or glycopeptide with an aminoglycoside, for prolonged period of 4-6 weeks, with a successful outcome. The PVE cases were treated with the appropriate antibiotics as per the antibiotic susceptibility report.
    Conclusion
    The high morbidity and mortality rates are associated with IE and hence accurate identification of aetiological agents and appropriate antimicrobial therapy is required.
    Keywords: Native valve endocarditis, Prosthetic valveendocarditis, Congestive heart failure
  • Hossein Sedaghat, Bahram Nasr Esfahani, Sina Mobasherizadeh, Azhar Sallari Jazi, Mehrdad Halaji, Parisa Sadeghi, Mohammad Emaneini, Seyed Asghar Havaei Pages 264-270
    Background And Objectives
    Macrolide, lincosamide and streptogramin B (MLSB) are noteworthy antibiotics for the treatment of Staphylococcus aureus infections. The purpose of this study, was to determine the phenotypic and genotypic characterization of macrolide resistance, among S. aureus, isolated from clinical samples and nasal swabs.
    Materials And Methods
    Totally, 162 non-duplicate S. aureus isolates were collected from clinical samples and nasal swabs, from patients and healthcare workers (HCWs), between March 2016 and September 2016, at four teaching hospitals in Isfahan. The antibiotic resistance profile was determined using disk diffusion test and the presence of resistance genes was detected, using PCR.
    Results
    Of 162 S. aureus isolates, 43.8% (71/162) and 34% (55/162) isolates were erythromycin-resistant and methicillin-resistant S. aureus (MRSA), respectively. The prevalence of constitutive MLSB (cMLSB), inducible MLSB (iMLSB), macrolide-streptogramin B-resistant (MSB) and lincosamide-streptogramin-A resistance (LSA) phenotype was 32%, 6%, 6% and 2%, respectively. The most common erythromycin resistance genes, in S. aureus isolates were ermC (35.2%), followed by ermA (20.4%) and msrA (17.3%). Meanwhile, msrA was detected in 43.6% of MRSA isolates. The frequency of coexistence of ermA窹苺欫, in S. aureus isolates was 7% and it was only detected in MRSA isolates.
    Conclusion
    In the current study, cMLSB phenotype was the most common erythromycin resistance pattern and ermC was the most prevalent gene in erythromycin-resistant isolates. The results revealed that the various mechanisms of erythromycin resistance are expanding in Isfahan.
    Keywords: Staphylococcus aureus, Inducible resistance, D-test, erm A, ermC, msrA
  • Maryam Roham, Mahnoush Momeni, Mohsen Saberi, Rahil Kheirkhah, Ali Jafarian, Hossein Rahbar Pages 271-276
    Background And Objectives
    Currently, there are no well-defined guidelines or criteria for catheter-site care in burn patients, and there is little information about the epidemiology of central vein catheter (CVC) infection in such patients. This study aimed at addressing the epidemiological aspect of CVC infection in a sample of Iranian burn patients admitted to the largest referral burn center in Iran, Motahari Burn Center.
    Materials And Methods
    A total of 191 burn patients were eligible for the study. Catheter related blood stream infection (CRBSI) was diagnosed according to suspected line infection, sepsis or blood culture growing bacteria, which could not have been associated with another site.
    Results
    Of the 191 patients in this study, 45 males (23.68%) and 19 females (10%) had positive blood culture, confirming CV line infection. Patients who were burned by gas, gasoline ignition or burning Kerosene had the highest incidence of CV line infection. In contrast, patients burned by alcohol, pitch or thinner had the lower rate of CV line infection. Incidence of CV line infection was higher in patients with delay in presentation to the burn center (55.2%) when compared to those who presented without delay (22.8%). Pseudomonas aeruginosa was the most frequent colonizer of the wound culture (52.4%), the dominant strain of the first catheter tip culture (35%) and the dominant strain of the same day blood samples (53.8%). The mortality rate in patients diagnosed with CRBI was 21.9%.
    Conclusion
    One of the important factors related to CV line infection is delay inpresentation to the burn center. The rate of CV line infection was 20.64 in catheter days.
    Keywords: Central Vein Catheter, Infection, Burn wound
  • A Study of prevalence of Shigella species and antimicrobial resistance patterns in paediatric medical center, Ahvaz, Iran
    Roya Nikfar, Ahmad Shamsizadeh, Marjan Darbor, Soheila Khaghani, Mina Moghaddam Pages 277-282
    Background And Objectives
    Shigella infections are one of the major causes of diarrhea worldwide, and especially in developing countries. Antimicrobial resistance has complicated the empirical treatment. The aim of this study was to define the clinical and antibiotic resistance patterns of Shigella gastroenteritis cases.
    Materials And Methods
    Stool samples of patients with diarrhea and fever diagnosed with shigellosis were collected, from June 2013 to May 2014 at Abuzar Hospital, Iran. All samples were cultured for Shigella spp on selective and differential media. Shigella isolates were evaluated for antimicrobial resistance.
    Results
    Among 193 Shigella isolates, S. flexneri (64.8%) was the predominant species followed by S. sonnei (32.6%). The most frequent antibiotic resistance observed, was towards co-trimoxazole (89%), ampicillin (77%) and ceftriaxone (51%) and the lowest resistance were seen in ciprofloxacin (1.5%), azithromycin (7%).
    Conclusion
    Due to the high resistance to ceftriaxone, this drug is not recommended as an empirical therapy for shigellosis. However, azithromycin should be used as the first-line treatment for paediatric patients, suffering from shigellosis and ciprofloxacin can be used as an alternative.
    Keywords: Anti-microbial resistance, Shigella, Children
  • Farzaneh Firoozeh, Zeinab Mahluji, Ehsaneh Shams, Ahmad Khorshidi, Mohammad Zibaei Pages 283-287
    Background And Objectives
    New Delhi metallo-ß-lactamase (NDM) is a newly emerging metallo-ß-lactamases, which can destroy all β-lactams including carbapenems. Therefore, this study aimed at evaluating New Delhi metallo-ß-lactamase-1–production in clinical isolates of Klebsiella pneumoniae in Kashan, Iran.
    Materials And Methods
    In a cross-sectional study, 181 K. pneumoniae isolates were collected from clinical samples of patients, who referred to Shahid Beheshi hospital in Kashan during November 2013 and October 2014. Antimicrobial susceptibility patterns were determined using disk diffusion method, according to CLSI guidelines. Metallo-ß-lactamase (MBL) production was identified among imipenem- resistant K. pneumoniae isolates using imipenem-EDTA double disk synergy test (EDTA-IMP DDST). PCR method and sequencing were used to detect integron Class 1 and blaNDM-1 gene. Statistical analyses were performed using SPSS software Version 16.
    Results
    Of the 181 K. pneumoniae isolates, 36 (19.9 %) were imipenem-resistant strains. A total of 28 out of 36 (77.7%) imipenem- resistant K. pneumoniae isolates were identified as MBL producer strains. Also, 150 (82.9%) K. pneumoniae isolates carried intI1 gene, and 20 (11.1%) K. pneumoniae isolates harbored blaNDM-1 gene.
    Conclusion
    Our study revealed a high frequency of MBL production and the presence of blaNDM-1 among K. pneumoniae strains, especially among hospitalized patients, which is alarming. Moreover, the presence of Class 1 integrons in all multi-drug resistant K. pneumoniae isolates highlights the risk of rapid spread of the resistance genes, especially in clinical settings.
    Keywords: Carbapenemases, New Delhi metallo-ß-lactamase, Class 1 integron, Klebsiella pneumoniae
  • Sara Barati, Naghmeh Moori-Bakhtiari, Masoud Ghorbanpoor Najafabadi, Hassan Momtaz, Leili Shokuhizadeh Pages 288-294
    Background And Objectives
    Enzootic abortion of ewes (EAE) is caused by infection of sheep and goats by Chlamydia abortus bacterium. Chlamydial abortion in bovine could occur by Chlamydia abortus, Chlamydia psittaci and Chlamydia pecorum. C. psittaci is the causative agent of psittacosis or ornithosis disease in humans and birds. It also causes acute pneumonia in cattle and sheep. The present study aimed at surveying the role of chlamydial agents in ruminants abortion.
    Materials And Methods
    A total of 117 aborted material samples (Cotyledon, liver, spleen, and abomasal contents of fetus) from 9 cattle and 100 sheep in Shahr-e-Kord and 8 sheep from Bagh-e-Malek were collected from different herds with abortion history during the lambing periods from 2014 to 2016. After DNA extraction, the samples were tested by species-specific PCR to detect C. abortus, C. pecorum and C. psittaci.
    Results
    Out of 117 clinical sample (108 sheep and 9 cattle), chlamydial infection was detected in 66 (56.41%) samples by Chlamydiales order-specific primers. A total of 24 (36.36%) and 24 (36.36%) samples indicated positive forms of C. abortus and C. psittasi infections, respectively. Only 1 (1.5%) C. pecorum was identified from cattle using nested PCR during this study. Among 66 Chlamydiales- positive samples, 20 (30.30%) samples with coinfection of C. abortus and C. psittaci were detected, however, infection of 3 species was not detected in the samples.
    Conclusion
    Because of the high percentage of chlamydial infection in these regions and probability of coinfection, conducting epidemiological studies on the role of different animals is highly recommended.
    Keywords: Abortion, Chlamydia, Goat, PCR, Sheep
  • Arusha P. Nandimath, Dilip D. Karad, Shantikumar G. Gupta, Arun S. Kharat Pages 295-304
    Background And Objectives
    Alkaline pH of the soil facilitates the conversion of phosphate present in phosphate fertilizer applied in the field to insoluble phosphate which is not available to plants. Problem of soluble phosphate deficiency arises, primarily due to needless use of phosphate fertilizer. We sought to biofertilizer with the thermo-tolerant phosphate solubilizing actinomycetes consortium that could convert insoluble phosphate to soluble phosphate at wider temperature range.
    Materials And Methods
    In the present investigation consortium of five thermo-tolerant phosphate solubilizing actinomycetes was applied for preparation of inoculum to produce multipurpose bio-fertilizer. Phosphates solubilizing thermo-tolerant 32 actinomycetes strains were processed for identification with the use of PIBWIN software and were screened for phosphate solubilizing activity.
    Results
    Amongst these five actinomycetes were selected on the basis of their ability to produce cellulase, chitinase, pectinase, protease, lipase, amylase and phosphate solubilizing enzymes. Ability to produce these enzymes at 28°C and 50°C were examined. Biofertilizer was prepared by using agricultural waste as a raw material. While preparation of bio-fertilizer the pH decreased from 7.5 to 4.3 and temperature increased up to 74°C maximum at the end of 4th week and in subsequent week it started to decline gradually till it reached around 50°C, which was found to be stable up to eighth week. This thermo-tolerant actinomycetes consortium released soluble phosphate of up to 46.7 µg ml-1.
    Conclusion
    As the mesophilic organisms die out at high temperature of composting hence thormo-tolerant actinomycetes would be the better substitute for preparation of phosphate solubilizing bio-fertilizer with added potential to degrade complex macromolecules in composting.
    Keywords: Phosphate solubilizing actinomycetes, Thermo-tolerant, Consortium inoculum, Biofertilizer
  • Tahereh Donyavi, Mojgan Bandehpour, Bahram Kazemi Pages 305-311
    Background And Objectives
    Leishmania are intracellular flagellate protozoan parasites cause a wide spectrum of clinical manifestations in human. The immunological basis for resistance against leishmaniasis depends on Thl responses in the course of performance of cytokines like IL-12. In this study, a transgenic Leishmania coding human IL-12 was produced that can be used in Leishmanization.
    Materials And Methods
    A fragment of Iranian lizard Leishmania (I.L.L) gene, named Cysteine Peptidase C (CPC), was amplified separately as two parts with PCR reaction. Then, they were attached using SOEing PCR such that the restriction site of SalI was placed in the middle of it. SOEing PCR product was purified and cloned in HindIII restriction site of pGEM-7z-f and named pKDB-CPC. After clone optimization, the hIL-12 construct was cloned in SalI restriction site of pKDB-CPC and named pKDB-IL12. Prokaryotic section of the above construct was removed and transferred into I.L.L by electroporation.
    Results
    Production of recombinant hIL-12 in transgene parasites was proved by ELISA. rhIL-12 secreted into supernatant culture medium accumulated at concentrations up to 246.53 ± 15.92 pg.mL-1.
    Conclusion
    Targeted gene replacement into the I.L.L genome using plasmid pKDB-cpc identical replacement process was successfully completed for the first time. Stabilized recombinant DNA consist of target gene didn’t have any toxicity for the parasite. Transgenic I.L.L produced and secreted active human interleukin 12 and can be an appropriate candidate for Leishmanization.
    Keywords: hIL-12, Iranian lizard Leishmania, Cysteine Peptidase C, Leishmanization