scholarly journals A comparative characterization of nasal and clinical isolates of Staphylococcus aureus from west of Iran

2021 ◽  
Author(s):  
Gholamreza Goudarzi ◽  
Yaser Hasanvand ◽  
Faranak Rezaei ◽  
Somayeh Delfani
Keyword(s):  
Staphylococcus Aureus ◽  
Antibiotic Resistance ◽  
Healthcare Workers ◽  
Meca Gene ◽  
Staphylococcal Enterotoxin ◽  
Healthcare Personnel ◽  
Clinical Samples ◽  
Resistance Pattern ◽  
Clinical Specimens ◽  
Significant Difference

Background and Objectives: Recently, the rise of methicillin-resistant Staphylococcus aureus (MRSA) isolated from hos- pital healthcare workers (HCWs) and various infectious samples has become one of the main concerns in hospital settings. Therefore, epidemiological studies are necessary to monitor antibiotic resistance patterns in each region and to study the pathogenesis of this strain to control infections. Materials and Methods: In this cross-sectional study, a total of 100 S. aureus isolates, including 50 isolates obtained from the anterior nares of healthcare workers, as well as 50 other isolates cultured from the various clinical specimens from the referral hospitals in Khorramabad (West of Iran) were tested. All isolates were examined to determine antibiotic resistance pattern, and the presence of staphylococcal enterotoxin A (sea), staphylococcal enterotoxin B (seb) and mecA genes. Results: The mecA gene was found among 36% (18/50) of the clinical S. aureus isolates (CSIs) and 14% (7/50) of nasal S. aureus isolates (NSIs), with statistically significant difference (X2 = 6.53; p = 0.011). The difference between the frequency rate of sea gene among MRSA strains isolated from clinical specimens (46.6%, 7/15) was significant compared to strains isolated from nostrils (14.3%, 1/7) (X2 = 3.85; p = 0.049). Conclusion: The frequency of mecA, sea, and seb genes among the clinical samples was more than strains isolated from the nostrils of healthcare personnel.

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.

scholarly journals Antibiotic resistance pattern of Staphylococcus aureus with reference to MRSA isolates from pediatric patients

2019 ◽  
Author(s):  
Raja Ram Gurung ◽  
Prashanna Maharjan ◽  
Ganga GC
Keyword(s):  
Staphylococcus Aureus ◽  
Antibiotic Resistance ◽  
Pediatric Patients ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Current Status ◽  
Clinical Samples ◽  
Resistance Pattern ◽  
Isolation And Identification ◽  
Cross Sectional ◽  
Methicillin Resistant

Abstract Background: Staphylococcus aureus is one of the important superbugs distributed throughout the world. It causes minor skin infections to severe complications including nosocomial infections in both hospitals and community settings. These strains have multi-drug resistant property. Hence, they are difficult to manage which increase health-related costs and simultaneously intensifying the need for new antibiotics. The extent of Methicillin-Resistant Staphylococcus aureus (MRSA) in children is largely unknown. The study determines the current status of S. aureus and MRSA causing various infections in pediatric patients visiting International Friendship Children’s Hospital (IFCH). Methods: A cross-sectional study was conducted among patients visiting a hospital. Various clinical specimens were aseptically collected and processed according to standard microbiological procedures. Isolation and identification of S. aureus were done by microscopy, mannitol fermentation, and coagulase positivity. All identified S. aureus isolates subjected to in-vitro antibiogram by Kirby-Bauer disc diffusion technique adopting Clinical and Laboratory Standards Institute (CLSI) guideline. Isolates resistant to cefoxitin were considered to be MRSA. Whereas, isolates produced D-shaped inhibition zone around clindamycin when kept near erythromycin were considered to be Inducible Clindamycin Resistant (ICR). Results: 672 various types of clinical samples were processed from the microbiology laboratory from June and November 2015. Out of 300 culture positive samples, 52 (17.3%) were S. aureus isolates, among them 39 (75.0%) were found to be MRSA. The D-test showed that Macrolide-Lincosamide-Streptogramin-B (MLSB) phenotype was 15.4%. Conclusion: The study shows the MRSA occurrence is prevalent in pediatric patients and newer classes’ drugs are found more effective than β-lactam drugs to treat S. aureus infection. However, restriction on the indiscriminate use of such drugs may be an effective strategy to control the drug resistance. Keywords: Methicillin-Resistant Staphylococcus aureus (MRSA), Macrolide-Lincosamide-Streptogramin B (MLSB) phenotype, Inducible Clindamycin Resistant (ICR) test or D-zone test, Antibiotic resistance, Nepal

Phenotypic characterization and Molecular detection of Inducible and Constitutive Clindamycin resistance among Staphylococcus aureus isolates in a Tertiary Care Hospital

2021 ◽  
pp. 3799-3804
Author(s):  
Mahalakshmi G. ◽  
Neelusree P. ◽  
Kalyani M.
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Tertiary Care ◽  
Phenotypic Characterization ◽  
Clinical Samples ◽  
Resistance Pattern ◽  
Care Hospital ◽  
Methicillin Resistant ◽  
Inducible Clindamycin Resistance ◽  
Significant Difference

Background: Staphylococcus aureus is Gram positive cocci. The pyogenic bacteria which is responsible for a variety of diseases that ranges in severity from mild skin and soft tissue infections to life-threatening conditions such as endocarditis, pneumonia, and sepsis. There is a scenario of increasing Methicillin-resistant Staphylococcus aureus (MRSA) infections, the macrolide-lincosamide-streptogramin B (MLSB) group of antibiotics they have different structure with same mechanism of action which serves as one good alternative. There is a frequency of increasing Methicillin Resistant Staphylococcus aureus (MRSA) infections and their change in antimicrobial resistance pattern. There is a concern about use of this antibiotic in the presence of Erythromycin resistance because of the possibility of inducible resistance among the members of Macrolide, lincosamide, Strepto-gramin B (MLSB) group. The invitro resistance exhibited by Staphylococcus aureus to erythromycin, Clindamycin, and other drugs of MLSB groups is due to the expression of ribosomal methylases(erm) genes. The detection of inducible Clindamycin resistance can limit the effectiveness of these drugs. Objective of the study: To isolate of Staphylococcus aureus from various clinical samples to differentiate between Methicillin resistant Staphylococcus aureus (MRSA) and Methicillin sensitive Staphylococcus aureus (MSSA) by conventional methods. To detect inducible and constitutive Clindamycin resistance in Staphylococcus aureus isolates by D test. To detect ermA gene responsible for resistance by PCR. Methodology: This cross sectional study was done for a period of six months. Totally 106 Staphylococcus aureus isolates was obtained various clinical samples were processed using standard guidelines. Result: From the 106 isolates of Staphylococcus aureus 67(63.3%) were MSSA and 39(36.7%) were MRSA. D-test was positive in n=9 of the n=21 MRSA and n=17 of the n=85 MSSA, which denotes inducible Clindamycin resistance. N- 9 of MRSA and n=13(22%) of MSSA showed Constitutional Clindamycin resistance. The statistics show that there is a significant Difference in constitutive resistance between MRSA and MSSA. In India ermA gene is most prevalent, out of 22 d-test positive n=13 ermA gene were detected (n=3-MRSA and n=10-MSSA) by using conventional PCR. Conclusion: The MLSB family of antibiotics is one such alternative and CD is preferred. Clinical microbiology laboratories should report inducible Clindamycin resistance in Staphylococcus aureus and D-test can be used as a simple, auxiliary and reliable method to Delineate inducible and constitutive Clindamycin resistance in routine clinical laboratories.

scholarly journals Investigation of antibiotic resistance pattern of Staphylococcus aureus in clinical samples of animals and humans from selective areas of Bangladesh

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
M. A. Islam ◽  
M. S. Uddin ◽  
M. J. Islam ◽  
M. U. Ahmed ◽  
M. M. Alam
Keyword(s):  
Staphylococcus Aureus ◽  
Antibiotic Resistance ◽  
Fusidic Acid ◽  
Animal Origin ◽  
Diffusion Method ◽  
Clinical Samples ◽  
Resistance Pattern ◽  
Antibiotic Resistance Pattern ◽  
Potential Pathogen

Background: Staphylococcus aureus (S. aureus) is a potential pathogen responsible for producing various infectious diseases. Determination of the prevalence of S. aureus infections both in animals and humans and elucidation of their antibiotic resistance pattern is crucial. The objective of this study was to find out the prevalence of Staphylococcal diseases in animals and humans, and their resistance pattern to commonly used antibiotics. Methods: A total of 100 animal and 100 human clinical samples were analyzed by traditional method. The S. aureus was identified by their cultural characteristics, gram’s staining, and catalase and coagulase tests. Antibiotic resistance pattern of the isolates was determined by disc diffusion method using various types of antibiotics. Results: The prevalence of S. aureus in animals and humans were 54% and 40%, respectively. S. aureus isolates of animal origin were highly resistant against penicillin (64.81%) and oxytetracycline (42.59%), and the lowest resistance was against oxacillin (7.40 %). S. aureus isolates from human were also showed a higher percentage of resistance against penicillin (87.5%) then oxacillin, cloxacillin, amoxicillin (37.5% each), and lowest resistance was observed against fusidic acid (5%). Conclusion: The findings of this study will certainly help veterinary clinicians or physicians to select appropriate antibiotics like oxacillin and fusidic acid for the treatment of different types of staphylococcal infections.

scholarly journals Characteristics of Staphylococcus aureus Isolated From Clinical Specimens in a Tertiary Care Hospital, Kathmandu, Nepal

2020 ◽  
Vol 13 ◽  
pp. 117863612097269
Author(s):  
Shesh Narayan Kandel ◽  
Nabaraj Adhikari ◽  
Binod Dhungel ◽  
Upendra Thapa Shrestha ◽  
Khadga Bikram Angbuhang ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistance ◽  
Tertiary Care ◽  
Meca Gene ◽  
Significant Proportion ◽  
Diffusion Method ◽  
Clinical Samples ◽  
Care Hospital ◽  
Clinical Specimens ◽  
Culture Positive

Introduction: Methicillin resistant Staphylococcus aureus (MRSA) is a major human pathogen associated with nosocomial and community infections. mecA gene is considered one of the important virulence factors of S. aureus responsible for acquiring resistance against methicillin. The main objective of this study was to explore the prevalence, antibiotic susceptibility pattern, and mec A gene. Methods: A total of 39 isolates of S. aureus were isolated from 954 clinical specimens processed in Microbiology laboratory of Himal Hospital, Kathmandu. Antimicrobial susceptibility test (AST) was performed by Kirby-Bauer disc diffusion method using cefoxitin, and performed Polymerase Chain Reaction (PCR) for amplification of mecA gene in MRSA isolates. Results: Out of 954 clinical samples, (16.2%; 153/954) samples had bacterial growth. Among 153 culture positive isolates, 25.5% (39/153) were positive for S. aureus. Among 39 S. aureus (61.5%; 24/39) were multiple drug resistant (MDR). On AST, amoxicillin was detected as the least effective while vancomycin was the most effective. The prevalence of methicillin resistance was 46% (18/39) of which 72.2% (13/18) were positive for mecA gene in PCR assay. Conclusion: One in 4 culture positive isolates from the clinical specimens were S. aureus, of which almost two-thirds were MDR. Around half of the MDR showed MRSA and significant proportion of them were positive for mecA gene. This study concludes that the mecA gene is solely dependent for methicillin resistance in S. aureus but the presence of gene is not obligatory. PCR detection of the mecA gene is reliable, valid and can be suggested for the routine use in diagnostic laboratories.

scholarly journals Antibiotic Resistance Pattern and Detection of mecA Gene in Staphylococcus aureus Isolated from Iranian Hamburger Samples

2020 ◽  
Author(s):  
N. Momtaz Bokharaei ◽  
M.M. Soltan Dallal ◽  
M.R. Pourmand ◽  
Z. Rajabi
Keyword(s):  
Staphylococcus Aureus ◽  
Antibiotic Resistance ◽  
Fast Food ◽  
Methicillin Resistance ◽  
Meca Gene ◽  
Food Poisoning ◽  
Penicillin G ◽  
Resistance Pattern ◽  
Antibiotic Resistance Pattern ◽  
Common Causes

Background: Among the bacteria that cause food poisoning, Staphylococcus aureus is one of the most common causes of food poisoning worldwide. The aim of this study was to investigate the presence of S. aureus strains in Iranian hamburgers, analysis of their antibiotic resistance pattern, and molecular detection of mecA gene in isolated strains. Methods: A total of 100 Iranian handmade (traditional) and packaged (factory-made) hamburger samples were investigated for the existence of S. aureus. The pattern of antibiotic resistance and the presence of mecA genes were investigated by disk diffusion and molecular methods, respectively. Data were statistically analyzed by SPSS software v. 24. Results: The prevalence of S. aureus isolated in handmade hamburgers was significantly (p=0.008) higher than packaged ones. Most of 39 isolated S. aureus strains were susceptible to ciprofloxacin (31 isolate), chloramphenicol (27 isolate), and trimethoprim/sulfamethoxazole (37 isolate). The highest antibiotic resistance was observed for penicillin G followed by oxacillin and tetracycline. All isolates were found susceptible to vancomycin and gentamicin. Six S. aureus isolates which were evaluated for methicillin-resistance, contained the mecA gene. Conclusion: The high presence of the S. aureus in Iranian hamburgers and the remarkable antibiotic resistance emphasize the need for policies which enforce hygienic practices within the food industry and fast food outlets.

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