Antibiotic Resistance and Molecular Epidemiology of Methicillin-Resistant Staphylococcus aureus From Lower Respiratory Tracts: Multiresistance and High Prevalence of SCCmecIII Type

CHEST Journal ◽  
2012 ◽  
Vol 142 (4) ◽  
pp. 151A
Author(s):  
Haiqing Chu ◽  
Lan Zhao ◽  
Zhenming Zhang ◽  
Tao Gui ◽  
Lizhong Han ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antibiotic Resistance ◽  
Molecular Epidemiology ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Methicillin Resistant ◽  
High Prevalence

scholarly journals MOLECULAR EPIDEMIOLOGY OF THE COMMUNITY-ASSOCIATED METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS CLONES: A SYNTHETIC REVIEW

2018 ◽  
Vol 91 (1) ◽  
pp. 7-11 ◽  
Author(s):  
Lia Monica Junie ◽  
Ionuț Isaia Jeican ◽  
Luminița Matroș ◽  
Stanca Lucia Pandrea
Keyword(s):  
Staphylococcus Aureus ◽  
Antibiotic Resistance ◽  
North America ◽  
Molecular Epidemiology ◽  
Latin American ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Prescribing Practices ◽  
Methicillin Resistant ◽  
Specialized Institutions ◽  
Epidemiological Characteristics

The article presents a synthetic molecular characterization of the methicillin-resistant Staphylococcus aureus and describes the most important community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) clones that  circulate nowadays in the world: the main molecular and epidemiological characteristics, as well as notions related to the clinic of infections produced by these clones and their antibiotic resistance spectrum.The predominant clone of CA-MRSA in North America is USA300 – ST8-IV in North America, in Australia – Queensland (Qld) MRSA (ST93-IV), in Europe – ST80-IV, in Asia there is a high heterogeneity of clones population, in Africa the distribution of CA-MRSA clones is unclear, and in South America – USA 1100 and USA300-Latin American variant are predominant .The molecular diagnosis is performed by highly specialized institutions. The knowledge of clones allows the study of antibiotic resistance spectrum for each one, a fact of great importance for medical practice. Molecular epidemiology of the CA-MRSA shows that lowly restricted sales of antibiotics in shops and pharmacies, as well as medical prescribing practices without a laboratory investigation, especially in Eastern Europe and Asia, contribute to the development of new MRSA clones with increased resistance to antibiotics.

scholarly journals Mutation-Based Antibiotic Resistance Mechanism in Methicillin-Resistant Staphylococcus aureus Clinical Isolates

2021 ◽  
Vol 14 (5) ◽  
pp. 420
Author(s):  
Tanveer Ali ◽  
Abdul Basit ◽  
Asad Mustafa Karim ◽  
Jung-Hun Lee ◽  
Jeong-Ho Jeon ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antibiotic Resistance ◽  
Active Site ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Meca Gene ◽  
Resistance Mechanism ◽  
Ligand Docking ◽  
Clinical Samples ◽  
Allosteric Site ◽  
Methicillin Resistant

β-Lactam antibiotics target penicillin-binding proteins and inhibit the synthesis of peptidoglycan, a crucial step in cell wall biosynthesis. Staphylococcus aureus acquires resistance against β-lactam antibiotics by producing a penicillin-binding protein 2a (PBP2a), encoded by the mecA gene. PBP2a participates in peptidoglycan biosynthesis and exhibits a poor affinity towards β-lactam antibiotics. The current study was performed to determine the diversity and the role of missense mutations of PBP2a in the antibiotic resistance mechanism. The methicillin-resistant Staphylococcus aureus (MRSA) isolates from clinical samples were identified using phenotypic and genotypic techniques. The highest frequency (60%, 18 out of 30) of MRSA was observed in wound specimens. Sequence variation analysis of the mecA gene showed four amino acid substitutions (i.e., E239K, E239R, G246E, and E447K). The E239R mutation was found to be novel. The protein-ligand docking results showed that the E239R mutation in the allosteric site of PBP2a induces conformational changes in the active site and, thus, hinders its interaction with cefoxitin. Therefore, the present report indicates that mutation in the allosteric site of PBP2a provides a more closed active site conformation than wide-type PBP2a and then causes the high-level resistance to cefoxitin.

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