scholarly journals Genetic Characterization of Methicillin Resistant and Sensitive, Vancomycin Intermediate Staphylococcus aureus Strains Isolated from Different Iranian Hospitals

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Seyed Asghar Havaei ◽  
Amir Azimian ◽  
Hosein Fazeli ◽  
Mahmood Naderi ◽  
Kiarash Ghazvini ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Genetic Analysis ◽  
Clinical Samples ◽  
Different Types ◽  
Health Care Policies ◽  
Global Health Care ◽  
Vancomycin Resistant ◽  
Epidemiological Evaluation ◽  
Mrsa Strains

Background. Global concerns have been raised due to upward trend of Vancomycin Intermediate Staphylococcus aureus (VISA) and Vancomycin Resistant Staphylococcus aureus (VRSA) reports which mean casting doubt on the absolute effectiveness of the last line of antibiotic treatment for S. aureus, vancomycin. Hence, epidemiological evaluation can improve global health care policies. Methodology. 171 Isolates of Staphylococcus aureus were collected from different types of clinical samples in selected hospitals in Isfahan, Mashhad, and Tehran, Iran. Then, they were evaluated by agar screening, disk diffusion, and MIC method to determine their resistance to vancomycin and methicillin. The isolated VISA strains were then confirmed with genetic analysis by the evaluation of mecA and vanA genes, SCCmec, agr, and spa type, and also toxin profiles. MLST was also performed. Results and Conclusion. Our data indicated that 67% of isolated S. aureus strains were resistant to methicillin. Furthermore, five isolates (2.9%) had intermediate resistance to vancomycin (VISA). In contrast to usual association of VISA with MRSA strains, we found two isolates of MSSA-VISA. Therefore, our data suggests a probable parallel growing trend of VISA towards MSSA, along with MRSA strains. However, more samples are required to confirm these primarily data. Moreover, genetic analysis of the isolated VISA strains revealed that these strains are endemic Asian clones.

scholarly journals Isolation and Genetic Characterization of Vancomycin-resistant and mecC+ Methicillin-resistant Staphylococcus aureus Strains in Clinical Samples of Bojnurd, Northeastern Iran

2021 ◽  
Vol 14 (10) ◽  
Author(s):  
Parastoo Zarghami Moghaddam ◽  
Amir Azimian ◽  
Abbas Akhavan Sepahy ◽  
Alireza Iranbakhsh
Keyword(s):  
Staphylococcus Aureus ◽  
Tertiary Hospital ◽  
Clinical Samples ◽  
Spa Typing ◽  
Antibiotic Resistant ◽  
Methicillin Resistant ◽  
Alpha Hemolysin ◽  
Pcr Method ◽  
Vancomycin Resistant

Background: The emergence of antibiotic-resistant Staphylococcus aureus strains is one of the major concerns about the various staphylococcal infections. Vancomycin is one the most important effective antibiotics on staphylococcal lethal infections. To date, vancomycin-resistant strains are increasingly isolated in different parts of the world, and it is alerting. Objectives: The current study was designed to evaluate the prevalence, and antibiotic susceptibility pattern of methicillin-resistant S. aureus (MRSA) and vancomycin-resistant S. aureus (VRSA) isolates in the main tertiary hospital of Bojnurd, Iran. Methods: S. aureus isolates were collected from different clinical samples in Imam Reza Hospital of Bojnurd. After identification of isolates through using conventional methods, they were evaluated by agar screening, disk diffusion, and minimum inhibitory concentration (MIC) methods to determine resistance to vancomycin and methicillin. We also performed polymerase chain reaction (PCR) for the detection of mecA, mecC, vanA, and vanB genes. After confirmation of vancomycin resistance, genetic analysis was performed using SCCmec, agr, and spa typing, and multilocus sequence typing (MLST) methods on VRSA isolates. Results: We found four vancomycin-resistant isolates (1.29%). Also, 75% of isolates were resistant to cefoxitin. Using the PCR method, mecA was found in 73%, mecC in 0.64%, and vanA in 1.29% of isolates. Interestingly, we found two mecC positive isolates in MRSA isolates. The alpha-hemolysin (81.81%) and enterotoxin C (27%) had the highest and lowest toxins percentage, respectively. Among mecA positive isolates, SCCmecIV (37%), SCCmecIII (31.27%), SCCmecI (14%), SCCmecII (11%), and SCCmecV (5.7%) were the most prevalent SCCmec types, respectively. It should be noted that the two mecC positive isolates belonged to SCCmecXI. AgrI (76.29%) was the highest agr type. We recognized t037 as the dominant spa type, and ST239, ST6, ST97, and ST8 were found in VRSA isolates. Conclusions: In our study, the frequency of mecA genes in MRSA isolates was very high. It seems that the resistant isolates belonged to endemic clones of Iran.

scholarly journals Molecular characterization of vancomycin-resistant Staphylococcus aureus strains isolated from clinical samples: A three year study in Tehran, Iran

PLoS ONE ◽  
2017 ◽  
Vol 12 (8) ◽  
pp. e0183607 ◽  
Author(s):  
Marjan Shekarabi ◽  
Bahareh Hajikhani ◽  
Alireza Salimi Chirani ◽  
Maryam Fazeli ◽  
Mehdi Goudarzi
Keyword(s):  
Staphylococcus Aureus ◽  
Molecular Characterization ◽  
Clinical Samples ◽  
Vancomycin Resistant

scholarly journals Monitoring of multiresistant community-associated MRSA strains from patients with pathological processes of different localization

2018 ◽  
Vol 9 (2) ◽  
pp. 281-286
Author(s):  
T. V. Sklyar ◽  
K. V. Lavrentievа ◽  
V. G. Gavrilyuk ◽  
N. V. Kurahina ◽  
M. O. Vereshchaha ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Nasal Cavity ◽  
Fusidic Acid ◽  
Threshold Value ◽  
Urine Samples ◽  
Diffusion Method ◽  
Clinical Samples ◽  
Methicillin Resistant ◽  
Vancomycin Resistant ◽  
Mrsa Strains

The therapy of infections, caused by methicillin-resistant Staphylococcus aureus (MRSA) with multiple resistance to antibiotics remains one of the most acute problems all over the world. It is all the more complicated since a priori the MSRA strains are not sensitive to the group of β-lactam antibiotics and multiresistant isolates are resistant to other groups of antimicrobial preparations, including antibiotics of choice (rifampicin, vancomycin, fusidic acid, co-trimoxazole and linezolid). From the samples of biomaterials of patients with pathological processes of different localization, we isolated 335 strains of bacteria, which were identified as Staphylococcus aureus, 169 (50.4%) of which were methicillin-resistant variants: 57.5% cultures were isolated from the nasal discharge; 50.7% – from faeces at intestinal dysbioses; by 40.0% – from conjunctival discharge, pharyngeal swab, outer ear swab and sputum; 33.3% – from urine samples. Antibiotic susceptibility of the isolated cultures was estimated by the disc-diffusion method and the method of serial dilution. The MRSA strains appeared to be most resistant to gentamycin, erythromycin (by 59.5% of cultures) and ciprofloxacin (53.3% of isolates), most sensitive – to vancomycin, co-trimoxazole and fusidic acid. The frequency of isolation of the cultures that are resistant to antibiotics did not exceed 4.1%. Rifampicin suppressed the growth of 75.8% and linezolid – of 100.0% of strains. Depending on the kind of biomaterial taken, MRSA strains, isolated from the nasal cavity, outer ear, urine samples, samples of sputum and faeces at intestinal dysbioses proved to be most resistant to the tested antimicrobial preparations. Rifampicin- and vancomycin-resistant strains of methicillin-resistant staphylococci made up 21.3% of the total number of the detected MRSA. They were most often isolated from the clinical samples taken from the nasal cavity and faeces. When determining minimal inhibitory concentration (MIC) of rifampicin and vancomycin, which are antibiotics of choice for treatment of infections caused by multiresistant MRSA, it was found that for 55.5% of the MRSA strains isolated from faeces, MIC of rifampicin coincided with the threshold value for this antibiotic and for 44.5%, it exceeded the threshold value by 2 times (4 µg/ml). 22.2% of them were characterized by the critical value of susceptibility to vancomycin (MIC ≥ 2 µg/ml). From rifampicin- and vancomycin-resistant MRSA stains, isolated from the nasal cavity, MIC of rifampicin coincided with the threshold value for this antibiotic for 66.7% of cultures, and exceeded it at least by 2 times for 33.3%. 11.1% of them were characterized by the critical level of susceptibility to vancomycin (MIC ≥ 2 µg/ml) and by 3.7% of strains exceeded MIC by 2 and 4 times respectively (4 and 8 µg/ml).

scholarly journals Characterization of Passage-Selected Vancomycin-Resistant Staphylococcus aureus Strains of Diverse Parental Backgrounds

2000 ◽  
Vol 44 (2) ◽  
pp. 294-303 ◽  
Author(s):  
Richard F. Pfeltz ◽  
Vineet K. Singh ◽  
Jennifer L. Schmidt ◽  
Michael A. Batten ◽  
Christopher S. Baranyk ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Walls ◽  
Methicillin Resistance ◽  
Surface Hydrophobicity ◽  
Whole Cell ◽  
Transmission Electron ◽  
Vancomycin Mics ◽  
Vancomycin Resistant ◽  
Doubling Times

ABSTRACT A series of 12 Staphylococcus aureus strains of various genetic backgrounds, methicillin resistance levels, and autolytic activities were subjected to selection for the glycopeptide-intermediate S. aureus (GISA) susceptibility phenotype on increasing concentrations of vancomycin. Six strains acquired the phenotype rapidly, two did so slowly, and four failed to do so. The vancomycin MICs for the GISA strains ranged from 4 to 16 μg/ml, were stable to 20 nonselective passages, and expressed resistance homogeneously. Neither ease of acquisition of the GISA phenotype nor the MIC attained correlated with methicillin resistance hetero- versus homogeneity or autolytic deficiency or sufficiency. Oxacillin MICs were generally unchanged between parent and GISA strains, although the mec members of both isogenic methicillin-susceptible and methicillin-resistant pairs acquired the GISA phenotype more rapidly and to higher MICs than did their susceptible counterparts. Transmission electron microscopy revealed that the GISA strains appeared normal in the absence of vancomycin but had thickened and diffuse cell walls when grown with vancomycin at one-half the MIC. Common features among GISAs were reduced doubling times, decreased lysostaphin susceptibilities, and reduced whole-cell and zymographic autolytic activities in the absence of vancomycin. This, with surface hydrophobicity differences, indicated that even in the absence of vancomycin the GISA cell walls differed from those of the parents. Autolytic activities were further reduced by the inclusion of vancomycin in whole-cell and zymographic studies. The six least vancomycin-susceptible GISA strains exhibited an increased capacity to remove vancomycin from the medium versus their parent lines. This study suggests that while some elements of the GISA phenotype are strain specific, many are common to the phenotype although their expression is influenced by genetic background. GISA strains with similar glycopeptide MICs may express individual components of the phenotype to different extents.

scholarly journals Genetic Analysis of a Vancomycin-Resistant Staphylococcus aureus Strain Isolated in Iran

mBio ◽  
2012 ◽  
Vol 3 (6) ◽  
Author(s):  
Amir Azimian ◽  
Seyed Asghar Havaei ◽  
Hosein Fazeli ◽  
Mahmood Naderi ◽  
Kiarash Ghazvini ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Genetic Analysis ◽  
Aureus Strain ◽  
Vancomycin Resistant

scholarly journals Prevalence of Methicillin Resistant and Virulence Determinants in Clinical Isolates of Staphylococcus aureus

2018 ◽  
Vol 10 (1) ◽  
pp. 108-115
Author(s):  
Manjunath Chavadi ◽  
Rahul Narasanna ◽  
Ashajyothi Chavan ◽  
Ajay Kumar Oli ◽  
Chandrakanth Kelmani. R
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Morphology ◽  
Methicillin Resistance ◽  
Protein A ◽  
Clinical Isolates ◽  
Clinical Samples ◽  
Virulence Determinants ◽  
Methicillin Resistant ◽  
Alternative Medicines ◽  
Mrsa Strains

Introduction:Methicillin-resistantStaphylococcus aureus(MRSA) is the major threat that is a result of the uncontrolled use of antibiotics causing a huge loss in health, so understanding their prevalence is necessary as a public health measure.Objective:The aim of this study was to determine the prevalence of methicillin-resistant MRSA and virulence determinant among associatedS. aureusfrom the clinical samples obtained from various hospital and health care centers of the Gulbarga region in India.Materials and Methods:All the collected samples were subjected for the screening ofS. aureusand were further characterized by conventional and molecular methods including their antibiotic profiling. Further, the response of methicillin antibiotic on cell morphology was studied using scanning electron microscopy.Results:A total 126S. aureuswas isolated from the clinical samples which showed, 100% resistant to penicillin, 55.5% to oxacillin, 75.3% to ampicillin, 70.6% to streptomycin, 66.6% to gentamicin, 8.7% to vancomycin and 6.3% to teicoplanin. The selected MRSA strains were found to possessmecA(gene coding for penicillin-binding protein 2A) andfemA(factor essential for methicillin resistance)genetic determinants in their genome with virulence determinants such as Coagulase (coa) and the X region of the protein A (spa)gene. Further, the methicillin response in resistantS. aureusshowed to be enlarged and malformed on cell morphology.Conclusion:The molecular typing of clinical isolates ofS. aureusin this study was highly virulent and also resistant to methicillin; this will assist health professionals to control, exploration of alternative medicines and new approaches to combat Staphylococcal infections more efficiently by using targeted therapy.

scholarly journals Activities of Oxadiazole Antibacterials against Staphylococcus aureus and Other Gram-Positive Bacteria

2018 ◽  
Vol 62 (8) ◽  
Author(s):  
Sara Ceballos ◽  
Choon Kim ◽  
Derong Ding ◽  
Shahriar Mobashery ◽  
Mayland Chang ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Gram Positive ◽  
Methicillin Resistant ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
Vancomycin Resistant Enterococci ◽  
Vancomycin Resistant ◽  
Mrsa Strains

ABSTRACT The activities of four oxadiazoles were investigated with 210 methicillin-resistant Staphylococcus aureus (MRSA) strains. MIC50 and MIC90 values of 1 to 2 and 4 μg/ml, respectively, were observed. We also evaluated the activity of oxadiazole ND-421 against other staphylococci and enterococci and in the presence of oxacillin for selected MRSA strains. The MIC for ND-421 is lowered severalfold in combination with oxacillin, as they synergize. The MIC90 of ND-421 against vancomycin-resistant enterococci is ≤1 μg/ml.

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