SUSCEPTIBILITY TESTING OF CLINICAL STAPHYLOCOCCUS AUREUS ISOLATES BY DIFFERENT METHODS AND STUDY OF ANTIBIOTIC RESISTANCE

2005 ◽  
Vol 14 (1) ◽  
pp. 1-12
Author(s):  
Hassan Abdel-Salam
Keyword(s):  
Staphylococcus Aureus ◽  
Antibiotic Resistance ◽  
Susceptibility Testing

Large-scale mass spectrometry data combined with demographics analysis rapidly predicts methicillin resistance in Staphylococcus aureus

2020 ◽  
Author(s):  
Zhuo Wang ◽  
Hsin-Yao Wang ◽  
Chia-Ru Chung ◽  
Jorng-Tzong Horng ◽  
Jang-Jih Lu ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Staphylococcus Aureus ◽  
Antibiotic Resistance ◽  
Large Scale ◽  
Operating Characteristic ◽  
Susceptibility Testing ◽  
Methicillin Resistance ◽  
Characteristic Curve ◽  
Mass Spectrometry Data ◽  
Treatment Efficiency

Abstract Background A mass spectrometry-based assessment of methicillin resistance in Staphylococcus aureus would have huge potential in addressing fast and effective prediction of antibiotic resistance. Since delays in the traditional antibiotic susceptibility testing, methicillin-resistant S. aureus remains a serious threat to human health. Results Here, linking a 7 years of longitudinal study from two cohorts in the Taiwan area of over 20 000 individually resolved methicillin susceptibility testing results, we identify associations of methicillin resistance with the demographics and mass spectrometry data. When combined together, these connections allow for machine-learning-based predictions of methicillin resistance, with an area under the receiver operating characteristic curve of >0.85 in both the discovery [95% confidence interval (CI) 0.88–0.90] and replication (95% CI 0.84–0.86) populations. Conclusions Our predictive model facilitates early detection for methicillin resistance of patients with S. aureus infection. The large-scale antibiotic resistance study has unbiasedly highlighted putative candidates that could improve trials of treatment efficiency and inform on prescriptions.

scholarly journals Differences in Method-Specific Vancomycin MICs and Induced Daptomycin Resistance in an Infective Endocarditis Patient

2015 ◽  
Vol 2015 ◽  
pp. 1-3
Author(s):  
David Benjamin Lash ◽  
Jeremiah Joson ◽  
Arash Heidari
Keyword(s):  
Staphylococcus Aureus ◽  
Antibiotic Resistance ◽  
Susceptibility Testing ◽  
Inhibitory Concentration ◽  
Infectious Agent ◽  
Empiric Therapy ◽  
Care Plan ◽  
High Burden ◽  
Source Of Infection ◽  
Vancomycin Mics

Methicillin-resistantStaphylococcus aureus(MRSA) is a common nosocomial infection that has a high burden of morbidity and mortality. Vancomycin is the often-used antibiotic of choice when MRSA is suspected as a causative infectious agent. Recent studies have called into question the reliability of vancomycin as empiric therapy, especially in instances of bacteremia. The isolate’s minimum inhibitory concentration (MIC), the source of infection, modality of susceptibility testing, and antibiotic resistance are all issues that should be taken into consideration when formulating a care plan for a patient. We present a case that illustrates some of these issues clinicians are facing.

scholarly journals Current Trend of Antibiotic Resistance in Lower Respiratory Tract Infections (LRTIs): An Experience in a Teaching Hospital in Bangladesh

2016 ◽  
Vol 19 (1) ◽  
pp. 85-91 ◽  
Author(s):  
Borkot Ullah ◽  
Sohel Ahmed ◽  
Masum Shahariar ◽  
Saquiba Yesmine
Keyword(s):  
Staphylococcus Aureus ◽  
Antibiotic Resistance ◽  
Respiratory Tract ◽  
Teaching Hospital ◽  
Lower Respiratory Tract ◽  
Respiratory Tract Infections ◽  
Susceptibility Testing ◽  
Lower Respiratory Tract Infections ◽  
Streptococcus Pneumonia ◽  
Tract Infections

Lower respiratory tract infections (LTRIs) are responsible for the vital causes of morbidity and mortality in all ages. In recent years, antibiotic resistance among respiratory pathogens is increasing emergently. The present study aimed to find out the bacterial etiology of LRTIs in Bangladesh and to update the clinicians about the current scenario of antibiotic resistance in lower respiratory tract infections. A total 64 bacterial pathogens from 100 patients with LRTIs were isolated from sputum specimens from a teaching hospital in Savar, Bangladesh between July- 2014 to June- 2015. The sputum specimens received within this year were subjected to analysis with microscopy, culture and susceptibility testing using conventional bacteriologic methods. Out of 100 processed sputum samples 64 (64%) cases had established bacterial etiology. Staphylococcus aureus (57.81%) was found to be the predominant organism in LRTIs followed by Streptococcus pneumonia (25%), Klebsiella and Pseudomonas species. Males (64.06%) were found to be more susceptible to LRTIs than that of females (35.93%). In antimicrobial susceptibility testing, grampositive organisms showed maximum sensitivity to imipenem (94.6%), meropenem (97.3%) and cefotaxime (75%). The resistance pattern varied for different organisms. Staphylococcus aureus isolates were mostly resistant to amoxicillin and ceftazidime (89.2%), whereas, Streptococcus pneumonia was to ceftazidime, amoxicillin and cotrimoxazole (81.2%). In case of gram negative isolates, Klebsiella sp. was mostly resistant to ceftriaxone, ceftazidime and amoxicillin (100%). Escherichia coli were resistant to amoxicillin, cotrimoxazole and vancomycin (100%). Therefore, appropriate identification of the causative organisms and their antibiotic resistance is crucial for right choice of antibiotic therapy in LRTIs.Bangladesh Pharmaceutical Journal 19(1): 85-91, 2016

scholarly journals Transient Silencing of Antibiotic Resistance by Mutation Represents a Significant Potential Source of Unanticipated Therapeutic Failure

mBio ◽  
2019 ◽  
Vol 10 (5) ◽  
Author(s):  
Louise Kime ◽  
Christopher P. Randall ◽  
Frank I. Banda ◽  
Francesc Coll ◽  
John Wright ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antibiotic Resistance ◽  
Clinical Microbiology ◽  
Pathogenic Bacteria ◽  
Susceptibility Testing ◽  
Genetic Defect ◽  
Antibiotic Resistance Genes ◽  
Clinical Microbiology Laboratory ◽  
Potential Threat ◽  
Content Type

ABSTRACT Sporadic literature reports describe isolates of pathogenic bacteria that harbor an antibiotic resistance determinant but remain susceptible to the corresponding antibiotic as a consequence of a genetic defect. Such strains represent a source from which antibiotic resistance may reemerge to cause treatment failure in patients. Here, we report a systematic investigation into the prevalence and nature of this phenomenon, which we term silencing of antibiotic resistance by mutation (SARM). Instances of SARM were detected among 1,470 Staphylococcus aureus isolates through side-by-side comparison of antibiotic resistance genotype (as determined by whole-genome sequencing) versus phenotype (as assessed through susceptibility testing). Of the isolates analyzed, 152 (10.3%) harbored a silenced resistance gene, including 46 (3.1%) that exhibited SARM to currently deployed antistaphylococcal drugs. SARM resulted from diverse mutational events but most commonly through frameshift mutation of resistance determinants as a result of point deletion in poly(A) tracts. The majority (∼90%) of SARM strains reverted to antibiotic resistance at frequencies of ≥10−9; thus, while appearing antibiotic sensitive in the clinical microbiology laboratory, most S. aureus isolates exhibiting SARM will revert to antibiotic resistance at frequencies achievable in patients. In view of its prevalence in a major pathogen, SARM represents a major potential threat to the therapeutic efficacy of antibiotics. IMPORTANCE Antibiotic resistance hinders the treatment of bacterial infection. To guide effective therapy, clinical microbiology laboratories routinely perform susceptibility testing to determine the antibiotic sensitivity of an infecting pathogen. This approach relies on the assumption that it can reliably distinguish bacteria capable of expressing antibiotic resistance in patients, an idea challenged by the present study. We report that the important human pathogen Staphylococcus aureus frequently carries antibiotic resistance genes that have become inactivated (“silenced”) by mutation, leading strains to appear antibiotic sensitive. However, resistance can rapidly reemerge in most such cases, at frequencies readily achievable in infected patients. Silent antibiotic resistance is therefore prevalent, transient, and evades routine detection, rendering it a major potential threat to antibacterial chemotherapy.

scholarly journals Expanding U.S. Laboratory Capacity for Neisseria gonorrhoeae Antimicrobial Susceptibility Testing and Whole-Genome Sequencing through the CDC's Antibiotic Resistance Laboratory Network

2020 ◽  
Vol 58 (4) ◽  
Author(s):  
Ellen N. Kersh ◽  
Cau D. Pham ◽  
John R. Papp ◽  
Robert Myers ◽  
Richard Steece ◽  
...  
Keyword(s):  
Public Health ◽  
Antibiotic Resistance ◽  
Neisseria Gonorrhoeae ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Whole Genome ◽  
Content Type ◽  
Laboratory Capacity

ABSTRACT U.S. gonorrhea rates are rising, and antibiotic-resistant Neisseria gonorrhoeae (AR-Ng) is an urgent public health threat. Since implementation of nucleic acid amplification tests for N. gonorrhoeae identification, the capacity for culturing N. gonorrhoeae in the United States has declined, along with the ability to perform culture-based antimicrobial susceptibility testing (AST). Yet AST is critical for detecting and monitoring AR-Ng. In 2016, the CDC established the Antibiotic Resistance Laboratory Network (AR Lab Network) to shore up the national capacity for detecting several resistance threats including N. gonorrhoeae. AR-Ng testing, a subactivity of the CDC’s AR Lab Network, is performed in a tiered network of approximately 35 local laboratories, four regional laboratories (state public health laboratories in Maryland, Tennessee, Texas, and Washington), and the CDC’s national reference laboratory. Local laboratories receive specimens from approximately 60 clinics associated with the Gonococcal Isolate Surveillance Project (GISP), enhanced GISP (eGISP), and the program Strengthening the U.S. Response to Resistant Gonorrhea (SURRG). They isolate and ship up to 20,000 isolates to regional laboratories for culture-based agar dilution AST with seven antibiotics and for whole-genome sequencing of up to 5,000 isolates. The CDC further examines concerning isolates and monitors genetic AR markers. During 2017 and 2018, the network tested 8,214 and 8,628 N. gonorrhoeae isolates, respectively, and the CDC received 531 and 646 concerning isolates and 605 and 3,159 sequences, respectively. In summary, the AR Lab Network supported the laboratory capacity for N. gonorrhoeae AST and associated genetic marker detection, expanding preexisting notification and analysis systems for resistance detection. Continued, robust AST and genomic capacity can help inform national public health monitoring and intervention.

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