فهرست مطالب

Jundishapur Journal of Microbiology - Volume:9 Issue: 1, 2016
  • Volume:9 Issue: 1, 2016
  • تاریخ انتشار: 1394/11/29
  • تعداد عناوین: 19
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  • Asma Manzoor *, Ikram Ul, Haq, Shahjhan Baig, Javed Iqbal Qazi, Sanja Seratlic Page 1
    Background
    Antibiotic resistance represents a serious global health threat to public health, so infections such as pneumonia and urinary tract infection (UTI) are becoming harder to treat. Therefore, it is necessary to develop an action plan to restrain the problem of antibiotic resistance. One approach in UTI control could be the use of lactobacilli because these indigenous inhabitants in human intestine have been found to play an important role in protecting the host from various infections..
    Objectives
    We sought to check the efficacy of locally isolated Lactobacillus species to eradicate antibiotic-resistant pathogenic bacteria causing UTI..
    Materials And Methods
    Lactic acid bacteria isolated from spoiled fruits and vegetables and grown in MRS medium were screened against multi-drug-resistant Candida albicans, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, and Enterococcus fecalis..
    Results
    Fifty-four lactic acid bacteria were isolated from spoiled fruits and vegetables, of which 11 Gram-positive and catalase-negative Lactobacillus isolates were identified by carbohydrate assimilation profiles as Lactobacillus acidophilus, L. paracasei, L. delbrueckii, L. casei, L. helveticus, L. brevis, L. salivarius, L. fermentum, L. rhamnosus, L. animalis, and L. plantarum. The latter organism had the highest abundance of all the samples, so its isolates were also verified through 16S rRNA gene sequencing. The isolated Lactobacilli were screened against multi-drug-resistant uropathogens, viz. C. albicans, P. aeruginosa, K. pneumoniae, E. fecalis, and E. coli. The growth inhibition zone (GIZ) was over 10 mm against all the uropathogenic test organisms, where L. fermentum and L. plantarum strains demonstrated remarkable inhibitory activities against E. coli and E. faecalis, with a GIZ up to 28 mm. The susceptibility test to 16 antibiotics showed multidrug resistance (3 to 5 antibiotics) among all the tested uropathogens..
    Conclusions
    The obtained results revealed that all the Lactobacillus isolates displayed antimicrobial activity against 6 out of 7 antibiotic-resistant uropathogens, indicating that these bacteria could represent a good ecological plan for the control and prevention of UTI..
    Keywords: Urinary Tract Infections, Antibiosis, Antibiotics Resistance
  • Mustafa Altindis *, Mehmet Koroglu, Tayfur Demiray, Tuba Dal, Mehmet Ozdemir, Ahmet Zeki Sengil, Ali Riza Atasoy, Metin Turan, Aysegul Copur Cicek, Gulfem Ece, Selcuk Kaya, Meryem Iraz, Bilge Sumbul Gultepe, Hakan Temiz, Idris Demirkan Page 2
    Background
    The prognostic value of blood culture testing in the diagnosis of bacteremia is limited by contamination..
    Objectives
    In this multicenter study, the aim was to evaluate the contamination rates of blood cultures as well as the parameters that affect the culture results..
    Materials And Methods
    Sample collection practices and culture data obtained from 16 university/research hospitals were retrospectively evaluated. A total of 214,340 blood samples from 43,254 patients admitted to the centers in 2013 were included in this study. The blood culture results were evaluated based on the three phases of laboratory testing: the pre-analytic, the analytic, and the post-analytic phase..
    Results
    Blood samples were obtained from the patients through either the peripheral venous route (64%) or an intravascular catheter (36%). Povidone-iodine (60%) or alcohol (40%) was applied to disinfect the skin. Of the 16 centers, 62.5% have no dedicated phlebotomy team, 68.7% employed a blood culture system, 86.7% conducted additional studies with pediatric bottles, and 43.7% with anaerobic bottles. One center maintained a blood culture quality control study. The average growth rate in the bottles of blood cultures during the defined period (1259 - 26,400/year) was 32.3%. Of the growing microorganisms, 67% were causative agents, while 33% were contaminants. The contamination rates of the centers ranged from 1% to 17%. The average growth time for the causative bacteria was 21.4 hours, while it was 36.3 hours for the contaminant bacteria. The most commonly isolated pathogens were Escherichia coli (22.45%) and coagulase-negative staphylococci (CoNS) (20.11%). Further, the most frequently identified contaminant bacteria were CoNS (44.04%)..
    Conclusions
    The high contamination rates were remarkable in this study. We suggest that the hospitals’ staff should be better trained in blood sample collection and processing. Sterile glove usage, alcohol usage for disinfection, the presence of a phlebotomy team, and quality control studies may all contribute to decreasing the contamination rates. Health policy makers should therefore provide the necessary financial support to obtain the required materials and equipment..
    Keywords: Blood Specimen Collection, Phlebotomy, Blood, Borne Pathogens, Bacteriological Techniques
  • Kimia Seifi, Hossein Kazemian, Hamid Heidari, Fereshteh Rezagholizadeh, Yasaman Saee, Fariba Shirvani, Hamidreza Houri* Page 3
    Background
    Klebsiella pneumoniae is among the most frequently recovered etiologic agents from nosocomial infections. This opportunistic pathogen can generate a thick layer of biofilm as one of its important virulence factors, enabling the bacteria to attach to living or abiotic surfaces, which contributes to drug resistance..
    Objectives
    The resistance of biofilm-mediated infections to effective chemotherapy has adverse effects on patient outcomes and survival. Therefore, the aim of the present study was to evaluate the biofilm-formation capacity of clinical K. pneumoniae isolates and to perform a molecular characterization using enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) to determine the dominant biofilm-producing genotype..Patients and
    Methods
    In the present study, 94 K. pneumoniae isolates were obtained from two hospitals in Tehran, Iran. Biofilm formation was assayed by a modified procedure, then ERIC-PCR was carried out..
    Results
    The distributions of the clinical specimens used in this study were 61.7% from urine, 18.1% from wounds, 11.7% from sputum, and 8.5% from blood. Among these isolates, 33% formed fully established biofilms, 52.1% were categorized as moderately biofilm-producing, 8.5% formed weak biofilms, and 6.4% were non-biofilm-producers. Genotyping of K. pneumoniae revealed 31 different ERIC types. Biofilm-formation ability in a special ERIC type was not observed..
    Conclusions
    Our results indicated that an enormous proportion of K. pneumoniae isolated from sputum and surgical-wound swabs produced fully established biofilms. It is reasonable to assume the existence of a relationship between the site of infection and the formation of biofilm. A high level of genetic diversity among the K. pneumoniae strains was observed..
    Keywords: Biofilm, PCR, Klebsiella pneumonia
  • Mohammad Savari, Soodabeh Rostami, Alireza Ekrami, Abbas Bahador* Page 4
    Background
    Pseudomonas aeruginosa is among the most problematic hospital and community-acquired pathogens. Toxin-antitoxin (TA) systems are maintenance regulatory systems in bacteria and have recently been considered new targets for antimicrobial therapy. The prevalence and transcription of these systems in clinical isolates are still unknown..
    Objectives
    The aim of this study was to characterize three types of TA systems (parDE, relBE, and higBA) among P. aeruginosa clinical isolates..
    Materials And Methods
    We typed our clinical isolates by ERIC-PCR (enterobacterial repetitive intergenic consensus sequence-based polymerase chain reaction) and BOX-PCR. We then investigated 174 P. aeruginosa clinical isolates from three hospitals in Ahvaz, Iran, for the presence of TA system genes, and determined whether these systems were encoded on chromosomes or plasmids by amplification of the flanking regions..
    Results
    Our results showed that in the 174 P. aeruginosa isolates, relBE and higBA were universal, but parDE was less prevalent. Both of the flanking regions of the parDE genes in all positive isolates were amplified. The flanking regions of nearly all relBE genes were amplified. Amplification was observed for the downstream sequence of every higBA locus, as well as for the region upstream of higBA, except in 14 strains..
    Conclusions
    Based on the presence of TA systems in the majority of P. aeruginosa isolates, these could be used as a novel target for antimicrobial therapy..
    Keywords: Gene Regulatory Networks, Resistance, Genotyping, Pseudomonas aeruginosa
  • Zhe Wu, Promchup Duangmanee, Pu Zhao, Niran Juntawong*, Chunhong Ma* Page 5
    Background
    Developing algal industries in saline-alkali areas is necessary. However, suitable strains and optimal production conditions must be studied before widespread commercial use..
    Objectives
    The effects of light, temperature, KNO3, and CO(NH2)2 on beta-carotene and biomass accumulation were compared and evaluated in order to provide scientific guidance for commercial algal production in northeastern Thailand..
    Materials And Methods
    An orthogonal design was used for evaluating optimal conditions for the algal production of three candidate Dunaliella salina strains (KU XI, KU 10 and KU 31) which were isolated from saline soils and cultured in the column photobioreactor..
    Results
    The optimal light and temperature for algae growth were 135.3 μmol m-2 s-1 and 22°C, while the conditions of 245.6 μmol m-2 s-1 and 22°C induced the highest level of beta-carotene production (117.99 mg L-1). The optimal concentrations of KNO3, CO(NH2)2, and NaHCO3 for algae growth were 0.5 g L-1, 0.36 g L-1, and 1.5 g L-1, respectively, while 0, 0.12 g L-1 and 1.5 g L-1 were best suited for beta-carotene accumulation. The highest beta-carotene rate per cell appeared with the highest light intensity (12.21 pg) and lowest temperature (12.47 pg), and the lowest total beta-carotene content appeared at the lowest temperature (15°C). There was not a significant difference in biomass accumulation among the three Dunaliella strains; however, the beta-carotene accumulation of KU XI was higher than that of the other two strains..
    Conclusions
    Light and temperature were both relevant factors that contributed to the growth and beta-carotene accumulation of the three D. salina strains, and NaHCO3 had significantly positive effects on growth. The degree of impact of the different factors on cell growth was temperature > NaHCO3 > light intensity > KNO3 > CO (NH2)2 > strains; the impact on beta-carotene accumulation was temperature > light intensity > KNO3 > CO (NH2)2 > strains > NaHCO3.
    Keywords: Beta, carotene, Biomass, Chlorophyll, Dunaliella salina
  • Fateh Rahimi Page 6
    Background
    Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most common nosocomial pathogens which can cause a broad spectrum of infections..
    Objectives
    The current study aimed to describe the frequency and antibiotic susceptibility patterns of clonal groups of gentamicin-resistant strains of MRSA isolated from a tertiary care hospital in Tehran, Iran..
    Materials And Methods
    A total of 301 S. aureus isolates were collected during January to November 2012. All of the isolates were identified at the species level and typed using the Phene-Plate (PhP) system. The antibiotic susceptibility patterns of the MRSA strains and the presence of different aminoglycoside resistance genes were determined..
    Results
    Of the 301 S. aureus isolates, 90 (29.9%) strains were confirmed as MRSA, and they showed high resistance to penicillin, ciprofloxacin, kanamycin, tobramycin, erythromycin, and tetracycline. On the other hand, 43 of the 90 strains (47.8%) were resistant to gentamicin. Aac (6’)-Ie + aph (2’’), ant (4’)-Ia, aph (3’)-IIIa, and ant (6)-Ia were detected in 65.6%, 42.2%, 20%, and 47.8% of the gentamicin-resistant strains, respectively. Diverse PhP types consisting of seven common types and four single types were identified among the strains..
    Conclusions
    Our results illustrated the presence of clonal groups of highly gentamicin-resistant strains of MRSA in hospitals in Tehran. The PhP typing method provided useful information for both clonal dissemination and determining the epidemiological links of the clonal groups of the MRSA strains..
    Keywords: Gentamicin, Hospital, Methicillin, Resistant Staphylococcus aureus
  • Patrik Mlynarcik *, Magdalena Roderova, Milan Kolar Page 7
    Background
    During the last decade, the prevalence of carbapenem-resistant Enterobacteriaceae in human patients has increased. Carbapenemase-producing bacteria are usually multidrug resistant. Therefore, early recognition of carbapenemase producers is critical to prevent their spread..
    Objectives
    The objective of this study was to develop the primers for single and/or multiplex PCR amplification assays for simultaneous identification of class A, class B, and class D carbapenem hydrolyzing β-lactamases in Enterobacteriaceae and then to evaluate their efficiency..
    Materials And Methods
    The reference sequences of all genes encoding carbapenemases were downloaded from GenBank. Primers were designed to amplify the following 11 genes: blaKPC, blaOXA, blaVIM, blaNDM, blaIMP, blaSME, blaIMI, blaGES, blaGIM, blaDIM and blaCMY. PCR conditions were tested to amplify fragments of different sizes. Two multiplex PCR sets were created for the detection of clinically important carbapenemases. The third set of primers was included for detection of all known carbapenemases in Enterobacteriaceae. They were evaluated using six reference strains and nine clinical isolates..
    Results
    Using optimized conditions, all carbapenemase-positive controls yielded predicted amplicon sizes and confirmed the specificity of the primers in single and multiplex PCR..
    Conclusions
    We have reported here a reliable method, composed of single and multiplex PCR assays, for screening all clinically known carbapenemases. Primers tested in silico and in vitro may distinguish carbapenem-resistant Enterobacteriaceae and could assist in combating the spread of carbapenem resistance in Enterobacteriaceae..
    Keywords: Enterobacteriaceae, Drug Resistance, Multiplex Polymerase Chain Reaction, Carbapenems
  • Mahdi Abastabar*, Hossein Mirhendi, Mohammad Taghi Hedayati, Tahereh Shokohi, Ali Rezaei, Matehkolaei, Rasoul Mohammadi, Hamid Badali, Maryam Moazeni, Iman Haghani, Aynaz Ghojoghi, Javad Akhtari Page 8
    Background
    The genus Penicillium contains a large number of ubiquitous environmental taxa, of which some species are clinically important. Identification of Penicillium down to the species level is currently based on polyphasic criteria, including phenotypic features and genetic markers. Biodiversity of the genus Penicillium from Mazandaran and Tehran provinces has not been described..
    Objectives
    The current paper focused on the environmental biodiversity of Penicillium isolates within some areas of Mazandaran and Tehran provinces, based on morphological traits and the molecular data from partial sequence of the β-tubulin (BT2) gene..
    Materials And Methods
    A total of 400 strains were isolated from the environment and investigated using morphological tests and sequencing of BT2, in order to characterize the spectrum of the Penicillium species..
    Results
    Sequence analysis of BT2 and morphological criteria of 20 strains representative of 10 species showed that Penicillium chrysogenum was the most prevalent species (n = 6), followed by P. polonicum (n = 3), P. glabrum (n = 2), P. palitans (n = 2), P. melanoconidium (n = 2), and other species, including P. expansum, P. canescense, P. griseofulvum, P. italicum, and P. raistrickii with one case each..
    Conclusions
    It was shown that partial β-tubulin sequence, as a reliable genetic target, supported specific morphological criteria for identification of the Penicillium species. Like other assessments throughout the world, P. chrysogenum remains the most frequent environmental Penicillium species in Mazandaran and Tehran Provinces..
    Keywords: Beta, Tubulin, PCR, DNA Sequencing, Penicillium
  • Amel M. Soliman, Sohair R. Fahmy, Amany A. Sayed*, Asmaa A. Abd El, Latif Page 9
    Background
    Sepsis remains a major problem for both scientists and clinicians. Cecal ligation and puncture (CLP) is considered the gold standard for animal models of sepsis. The undesirable side effects of certain antibiotics have forced scientists to discover new, natural, and safe antimicrobial agents, such as cephalopods, which are known to display significant antimicrobial activity..
    Objectives
    The present investigation aims to evaluate the in vitro and in vivo antibacterial and antiseptic efficacy of Sepia officinalis body tissue (SOBT) extract and S. officinalis polysaccharide (SOP) from its cuttlebone..
    Materials And Methods
    Forty-eight rats were divided into 4 groups, and starting 2 hours after CLP, treatments were given for 2 days as follows: sham control rats treated orally with distilled water, septic rats treated orally distilled water, septic rats treated orally methanolic extract of SOBT (500 mg/kg b.wt) suspended in distilled water, and septic rats treated orally SOP extract (200 mg /kg b.wt) dissolved in distilled water. On the third day, half of the rats in each group were euthanized for blood collection. The other half were kept alive and used for the survival study..
    Results
    The present study revealed that the SOBT and SOP extracts showed in vitro bactericidal activity against gram-positive and gram-negative bacteria. Furthermore, administration of SOBT and SOP increased the rats’ survival rates by 66.7% and 83.33%, respectively, as compared to the untreated CLP-septic rats. Treatment of the CLP-septic rats with SOBT and SOP significantly alleviated alterations in procalcitonin levels and in some hematological parameters induced by CLP..
    Conclusions
    SOBT and SOP had profound antiseptic efficacy..
    Keywords: Sepsis, Antibacterial Activity, Procalcitonin, Sepia Officinalis Body Tissue Extract, Sepia Officinalis Bone Polysaccharide Extract
  • Saba Rehman, Shahbaz Mujtaba Ghauri, Anjum Nasim Sabri* Page 10
    Background
    Otitis media can lead to severe health consequences, and is the most common reason for antibiotic prescriptions and biofilm-mediated infections. However, the increased pattern of drug resistance in biofilm forming bacteria complicates the treatment of such infections..
    Objectives
    This study was aimed to estimate the biofilm formation potential of the clinical isolates of otitis media, and to evaluate the efficacy of antibiotics and plant extracts as alternative therapeutic agents in biofilm eradication..
    Materials And Methods
    The ear swab samples collected from the otitis media patients visiting the Mayo Hospital in Lahore were processed to isolate the bacteria, which were characterized using morphological, biochemical, and molecular (16S rRNA ribotyping) techniques. Then, the minimum inhibitory concentrations (MICs) of the antibiotics and crude plant extracts were measured against the isolates. The cell surface hydrophobicity and biofilm formation potential were determined, both qualitatively and quantitatively, with and without antibiotics. Finally, the molecular characterization of the biofilm forming proteins was done by amplifying the ica operon..
    Results
    Pseudomonas aeruginosa (KC417303-05), Staphylococcus hemolyticus (KC417306), and Staphylococcus hominis (KC417307) were isolated from the otitis media specimens. Among the crude plant extracts, Acacia arabica showed significant antibacterial characteristics (MIC up to 13 mg/ml), while these isolates exhibited sensitivity towards ciprofloxacin (MIC 0.2 µg/mL). All of the bacterial strains had hydrophobic cellular surfaces that helped in their adherence to abiotic surfaces, leading to strong biofilm formation potential (up to 7 days). Furthermore, the icaC gene encoding polysaccharide intercellular adhesion protein was amplified from S. hemolyticus..
    Conclusions
    The bacterial isolates exhibited strong biofilm formation potential, while the extracts of Acacia arabica significantly inhibited biofilm formation among the isolates and, therefore, could be executed in the development of cost-effective biofilm inhibitor medicines..
    Keywords: Biofilms, Plant Extracts, Bacterial Adhesion, Bacterial Infections, Anti, Bacterial Agents
  • Parviz Mohajeri, Samira Azizkhani, Abbas Farahani*, Baharak Norozi Page 11
    Background
    Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterial pathogen frequently isolated in both hospital and community environments. Methicillin-resistant Staphylococcus aureus is considered a major nosocomial pathogen that causes severe morbidity and mortality..
    Objectives
    The main objective of this study was to determine the genotypes of MRSA strains isolated from the nares of hospitalized and community patients in Kermanshah Hospital, western Iran, by PCR-restriction fragment length polymorphism (PCR-RFLP)..
    Materials And Methods
    Of 1387 patients, 1217 patients were screened for more than 48 hours after admission in hospital wards and 170 patients were screened in the hemodialysis unit of Kermanshah Hospital, which is the largest hospital in western Iran. S. aureus was identified by standard biochemical tests, including colonial morphology, production of coagulase, and DNase and the API20 Staph test. Methicillin-resistant Staphylococcus aureus was identified by the Oxacillin strip test..
    Results
    In total, 258 S. aureus isolates were recovered from 1387 samples, of which 96 isolates were MRSA, 82 were hospital acquired, and 14 were community acquired. Digestion of the aro A gene revealed only one distinctive RFLP pattern in the 258 isolates..
    Conclusions
    Methicillin-resistant Staphylococcus aureus is an increasingly common cause of nosocomial infections. Our results are in agreement with those of other studies reporting that a few specialized clones are responsible for most cases of MRSA nasal carriage. In this study, MRSA strains isolated from different wards of hospital were closely related when analyzed by coagulase gene typing. Identifying patients colonized with MRSA during hospitalization and rapidly typing them with these methods may facilitate detection of outbreaks and prevention of the spread of organisms in hospitals..
    Keywords: Restriction Fragment Length Polymorphisms, Methicillin, Resistant Staphylococcus aureus, Coa gene, aroA gene, Staphylococcus aureus
  • Mojtaba Salouti*, Fatemeh Mirzaei, Reza Shapouri, Azam Ahangari Page 12
    Background
    Wound infection is a common problem in hospitals and is typically caused by the antibiotic-resistant Staphylococcus aureus, which is a major pathogen for skin and soft tissue infections worldwide..
    Objectives
    The aim of this study was to investigate the synergistic antibacterial effect of plant peptide MBP-1 and silver nanoparticles on infected wounds caused by S. aureus..
    Materials And Methods
    The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of MBP-1 and silver nanoparticles both on their own and in combination form were determined against S. aureus via macrodilution and microdilution methods. The synergistic antibacterial effect of silver nanoparticles and MBP-1 was investigated on infected wounds caused by S. aureus in a mouse model..
    Results
    The MIC and MBC of MBP-1 were found to be 0.6 and 0.7 mg/mL, respectively. MIC and MBC of silver nanoparticles were determined to be 6.25 and 12.5 mg/L, respectively. MIC and MBC of the silver nanoparticles and MBP-1 combination were found to be 3.125 mg/mL, 0.5 mg/L; and 6.25 mg/mL, 0.6 mg/L, respectively. The infected wound healed properly after the combined use of MBP-1 and silver nanoparticles..
    Conclusions
    The synergistic effect was found on the healing of infected wounds caused by S. aureus by using an MBP-1 and silver nanoparticles combination in a mouse model..
    Keywords: Wound Infection, Plant Peptide MBP, 1, Silver Nanoparticles, Antibacterial Activity, Staphylococcus aureus
  • Mansoureh Shahbazi Dastjerdeh, Shirin Kouhpayeh, Faezeh Sabzehei, Hossein Khanahmad*, Mansour Salehi, Zahra Mohammadi, Laleh Shariati, Zahra Hejazi, Parisa Rabiei, Mostafa Manian Page 13
    Background
    The evolution of antibiotic-resistant bacteria (ARB) and antibiotic-resistance genes (ARGs) has been accelerated recently by the indiscriminate application of antibiotics. Antibiotic resistance has challenged the success of medical interventions and therefore is considered a hazardous threat to human health..
    Objectives
    The present study aimed to describe the use of zinc finger nuclease (ZFN) technology to target and disrupt a plasmid-encoded β-lactamase, which prevents horizontal gene transfer-mediated evolution of ARBs..
    Materials And Methods
    An engineered ZFN was designed to target a specific sequence in the ampicillin resistance gene (ampR) of the pTZ57R plasmid. The Escherichia coli bacteria already contained the pZFN kanamycin-resistant (kanaR) plasmid as the case or the pP15A, kanaR empty vector as the control, were transformed with the pTZ57R; the ability of the designed ZFN to disrupt the β-lactamase gene was evaluated with the subsequent disturbed ability of the bacteria to grow on ampicillin (amp) and ampicillin-kanamycin (amp-kana)-containing media. The effect of mild hypothermia on the ZFN gene targeting efficiency was also evaluated..
    Results
    The growth of bacteria in the case group on the amp and amp-kana-containing media was significantly lower compared with the control group at 37°C (P < 0.001). Despite being more efficient in hypothermic conditions at 30°C (P < 0.001), there were no significant associations between the incubation temperature and the ZFN gene targeting efficiency..
    Conclusions
    Our findings revealed that the ZFN technology could be employed to overcome ampicillin resistance by the targeted disruption of the ampicillin resistance gene, which leads to inactivation of β-lactam synthesis. Therefore, ZFN technology could be engaged to decrease the antibiotic resistance issue with the construction of a ZFN archive against different ARGs. To tackle the resistance issue at the environmental level, recombinant phages expressing ZFNs against different ARGs could be constructed and released into both hospital and urban wastewater systems..
    Keywords: Ampicillin Resistance, Microbial Drug Resistance, Beta, Lactamases, Gene Targeting, Genome Editing, Zinc Finger Nuclease
  • Auttawit Sirichoat, Sujintana Wongthong, Ratdawan Kanyota, Ratree Tavichakorntrakool, Aroonwadee Chanawong, Jariya Umka Welbat, Aroonlug Lulitanond* Page 14
    Background
    Staphylococcus aureus, with reduced vancomycin susceptibility, is probably under the regulation of several genes and various express phenotypes..
    Objectives
    This study aimed to investigate the phenotypic differences between vancomycin-susceptible S. aureus (VSSA), vancomycin-intermediate S. aureus (VISA), and heterogeneous VISA (hVISA) isolates..
    Materials And Methods
    A total of 130 methicillin-resistant S. aureus (MRSA) isolates were studied, including 49 VSSA, 28 hVISA, and 5 VISA isolates from blood cultures and 48 isolates (two VSSA, six hVISA, and 40 VISA) derived in vitro (laboratory-induced/sub-passaged). Their phenotypes were examined using a coagulase tube test, colony spreading on soft agar, and urease activity. The SCCmec and agr typing were performed using multiplex PCR..
    Results
    Most of the MRSA isolates were SCCmec III-agr I (84.5%), followed by SCCmec II-agr II (11.8%). The average plasma coagulation time of vancomycin-non-susceptible isolates was longer than that of the susceptible isolates (12 vs. 2.6 hours). Four hVISA (P = 0.023) and nine VISA (P < 0.001) isolates yielded a negative coagulase test after 24-hour incubation. The percentage of VSSA isolates showing non-spreading colonies (accessory gene regulator (agr) dysfunction) was significantly lower than in the VISA group (P = 0.013), but no significant difference was found between VSSA and hVISA. The VISA group showed higher urease activity than that of the VSSA and hVISA groups (P = 0.002)..
    Conclusions
    There were diverse phenotypic changes among vancomycin-non-susceptible S. aureus isolates. This may be due to the variety of related regulatory systems. The diversity of phenotypic expression may result in its misidentification in routine laboratory checks..
    Keywords: Coagulase, Urease, Vancomycin, Methicillin, Resistant Staphylococcus aureus
  • Laleh Shariati, Majid Validi, Ali Mohammad Hasheminia, Reza Ghasemikhah, Fariborz Kianpour, Ali Karimi, Mohammad Reza Nafisi, Mohammad Amin Tabatabaiefar* Page 15
    Background
    A diversity of virulence factors work together to create the pathogenicity of Staphylococcus aureus. These factors include cell surface components that promote adherence to surfaces as well as exoproteins such as Panton-Valentine leukocidin (PVL), encoded by the luk-PV genes, that invade or bypass the immune system and are toxic to the host, thereby enhancing the severity of infections caused by methicillin-resistant Staphylococcus aureus (MRSA)..
    Objectives
    The aim of this study was to determine the frequency of PVL-positive MRSA strains by real-time PCR and their antibiotic susceptibility patterns by phenotypic test..
    Materials And Methods
    In total, 284 Staphylococcus isolates, identified by phenotypic methods from clinical samples of Shahrekord University Hospitals, Shahrekord, Iran, were tested for nuc, mecA, and PVL genes by TaqMan real-time PCR. The antibiotic susceptibility patterns of PVL-containing MRSA strains were determined via the disk diffusion method..
    Results
    In total, 196 isolates (69%) were nuc positive (i.e., S. aureus); of those isolates, 96 (49%) were mecA positive (MRSA). Eighteen (18.8%) of the 96 MRSA positive and 3 (3%) of the 100 methicillin-susceptible Staphylococcus aureus (MSSA) strains were PVL positive. PVL-positive MRSA strains were mostly recovered from tracheal specimens. Eight PVL-positive MRSA strains were resistant to all the tested antibiotics except vancomycin. A significant correlation (P = 0.001) was found between the mecA positivity and the presence of luk-PV genes..
    Conclusions
    Community acquired (CA)-MRSA is becoming a public health concern in many parts of the world, including Asian countries. The variable prevalence of luk-PV-positive MRSA isolates in different regions and their rather high frequency in pneumonia necessitate the application of rapid diagnostic methods such as real-time PCR to improve treatment effectiveness..
    Keywords: Panton, Valentine leukocidin, Real, Time PCR, Infectious Disease, Iran, Methicillin, Resistant Staphylococcus aureus
  • Muhammad Sohail*, Zakia Latif Page 16
    Background
    Keeping in mind the commercial application of polygalacturonase (PG) in juice and beverages industry, bacterial strains were isolated from rotten fruits and vegetables to screen for competent producers of PG..
    Objectives
    In this study, the plate method was used for preliminary screening of polygalacturonase-producing bacteria, while the Dinitrosalicylic Acid (DNS) method was used for quantifications of PG..
    Materials And Methods
    Biochemically-identified polygalacturonase-producing Bacillus and Pseudomonas species were further characterized by molecular markers. The genetic diversity among these selected strains was analyzed by investigating microsatellite distribution in their genome. Out of 110 strains, 17 competent strains of Bacillus and eight strains of Pseudomonas were selected, identified and confirmed biochemically. Selected strains were characterized by 16S rRNA sequencing and data was submitted to the national center for biotechnology information (NCBI) website for accession numbers..
    Results
    Among the Bacillus, Bacillus vallismortis (JQ990307) isolated from mango was the most competent producer of PG; producing up to 4.4 U/µL. Amongst Pseudomonas, Pseudomonas aeruginosa (JQ990314) isolated from oranges was the most competent PG producer equivalent to B. vallismortis (JQ990307). To determine genetic diversity of different strains of Pseudomonas and Bacillus varying in PG production, fingerprinting was done on the basis of Simple Sequence Repeats (SSR) or microsatellites. The data was analyzed and a phylogenetic tree was constructed using the Minitab 3 software for comparison of bacterial isolates producing different concentrations of PG. Fingerprinting showed that presence or absence of certain microsatellites correlated with the ability of PG production..
    Conclusions
    Bacteria from biological waste were competent producers of PG and must be used on an industrial scale to cope with the demand of PG in the food industry..
    Keywords: Polygalacturonase, Phylogenetic DNA, Dinitrosalicylic Acid (DNS) Method, Bacillus spp., Pseudomonas spp
  • Rukaia Gashgari, Youssuf Gherbawy, Fuad Ameen*, Salam Alsharari Page 17
    Background
    Endophytic fungi, which have been reported in numerous plant species, are important components of the forest community and contribute significantly to the diversity of natural ecosystems..
    Objectives
    The current study aimed to evaluate and characterize, at the molecular level, the diversity and antimicrobial activities of endophytic fungi from medicinal plants in Saudi Arabia..
    Materials And Methods
    Fungi growing on plant segments were isolated and identified based on morphological and molecular characteristics. The isolates were grouped into 35 distinct operational taxonomic units, based on the sequence of the internal transcribed spacer regions in the rRNA gene. The colonization frequency and the dominant fungi percentage of these endophytic fungi were calculated. A dual culture technique was adopted to investigate the antifungal activity of these endophytes..
    Results
    Tamarix nilotica showed the highest endophytic diversity with a relative frequency of 27.27%, followed by Cressa cretica with a relative frequency of 19.27%. The most frequently isolated species was Penicillium chrysogenum with an overall colonization rate of 98.57%. Seven out of 35 endophytic fungi exhibited strong antifungal activity to all plant fungal pathogens tested. P. chrysogenum, Fusarium oxysporum, and F. nygamai exhibited the highest inhibition against the human pathogenic bacteria Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae. Aspergillus sydowii, P. chrysogenum, and Eupenicillium crustaceum showed strong antimicrobial activity against Enterococcus faecalis..
    Conclusions
    The antimicrobial activity of these endophytic microorganisms could be exploited in biotechnology, medicine, and agriculture..
    Keywords: Endophytic Fungi, Medicinal Plants, Antimicrobial Activity
  • Bentol Hoda Zahraei, Mohammad Sadegh Hashem Zadeh, Mohammad Najar Asl, Samaneh Zahiri Yeganeh, Mahdi Tat, Maliheh Metanat, Nahid Sepehri Rad, Behzad Khansari Nejad, Ehsan Zafari, Mojtaba Sharti, Ruhollah Dorost Kar* Page 18
    Background
    The Crimean-Congo hemorrhagic fever (CCHF) virus causes severe disease in humans, with a high mortality rate. Since, there is no approved vaccine or specific treatment for CCHF, an early and accurate diagnosis, as well as reliable surveillance, is essential for case management and patient improvement..
    Objectives
    For this research, our aim was to evaluate the application of a novel SYBR Green based one-step real-time reverse-transcriptase polymerase chain reaction (rRT-PCR) assay for the in-house diagnosis of the CCHF virus..Patients and
    Methods
    In this experimental study, the highly conserved S-region sequence of the CCHF viral genome was first adapted from GenBank, and the specific primers targeting this region were designed. Then, the viral RNA was extracted from 75 serum samples from different patients in eastern Iran. The sensitivity and specificity of the primers were also evaluated in positive serum samples previously confirmed to have the CCHF virus, by this one-step rRT-PCR assay, as well as a DNA sequencing analysis..
    Results
    From a total of 75 suspected serum samples, 42 were confirmed to be positive for CCHF virus, with no false-positives detected by the sequencing results. After 40 amplification cycles, the melting curve analysis revealed a mean melting temperature (Tm) of 86.5 ± 0.6°C (quite different from those of the primer-dimers), and the positive samples showed only a small variation in the parameters. In all of the positive samples, the predicted length of 420 bp was confirmed by electrophoresis. Moreover, the sensitivity test showed that this assay can detect less than 20 copies of viral RNA per reaction..
    Conclusions
    This study showed that this novel one-step rRT-PCR assay is a rapid, reliable, repeatable, specific, sensitive, and simple tool for the detection of the CCHF virus..
    Keywords: Hemorrhagic Fever Virus, Crimean, Congo, Diagnosis, Real, Time Polymerase Chain Reaction
  • Koorosh Ahmadi, Amir Masoud Hashemian, Seyyed Mohsen Pouryaghobi, Reza Akhavan, Sara Rozmina, Ehsan Bolvardi* Page 19
    Background
    Pseudomonas aeruginosa, a ubiquitous opportunistic pathogen, is one of the main causative agents of human superficial infections. Infections due to these bacteria are difficult to heal and cause serious economic issues..
    Objectives
    The present study was carried out to investigate the antibiotic resistance pattern of P. aeruginosa isolated from cases of superficial infections referred to the emergency health care units of Iranian Hospitals..
    Materials And Methods
    Three hundred swab samples were collected from patients with superficial infections. Samples were cultured and those that were P. aeruginosa positive were analyzed by the disk diffusion method..
    Results
    One hundred and seventy-two out of 300 swab samples (57.3%) were positive for P. aeruginosa. The results of the culture technique were also confirmed using the polymerase chain reaction (PCR). Females had a higher prevalence of P. aeruginosa than males, patients older than 70 years were the most infected age group and finally burn infections had the highest prevalence of bacteria. P. aeruginosa strains had the highest levels of resistance against ampicillin (93%), gentamycin (89.5%), ciprofloxacin (82.5%) and amikacin (77.3%). The most effective drugs were meropenem (2.3%, imipenem (2.9%), polymyxin B (21.5%) and cotrimoxazole (31.9%)..
    Conclusions
    It is logical to primarily prescribe meropenem, imipenem, polymyxin B and cotrimoxazole in the cases of superficial infections caused by P. aeruginosa. Medical practitioners should be aware of the presence of such levels of antibiotic resistance in cases of superficial infections in Iran..
    Keywords: Antibiotic Resistance, Superficial Infection, Emergency Health Care Units, Iran, Pseudomonas aeruginosa