How does the density of bacteria affect the results of antibiogram susceptibility testing?4 answersThe density of bacteria can have an impact on the results of antibiogram susceptibility testing. Higher bacterial densities have been associated with decreased efficacy of antibiotics, including a decline in the rate and extent of antibiotic-mediated killing and an increase in minimum inhibitory concentration (MIC) ^[Udekwu et al.]. The density-dependent effects on antibiotic efficacy may vary depending on the specific antibiotic being tested. For some antibiotics, the density effect is primarily associated with a decrease in per-cell antibiotic concentration, while for others, it is due to density-dependent reductions in the effective concentration of the antibiotic ^[Udekwu et al.]. These findings suggest that the density of bacteria should be taken into account when determining the appropriate antibiotic treatment protocols, as conventional MICs may not accurately predict efficacy in higher density infections ^[Udekwu et al.].
What is the antibiotic susceptibility profile of Gram-negative bacteria in a hospital?5 answersThe antibiotic susceptibility profile of Gram-negative bacteria in hospitals shows a high prevalence of resistance to commonly used antibiotics. Studies have found that Gram-negative bacteria, such as Escherichia coli, Klebsiella spp., Acinetobacter spp., and Pseudomonas aeruginosa, exhibit resistance to cephalosporins, levofloxacin, and carbapenems. The resistance rates for third and fourth-generation cephalosporins range from 32% to 75%. Additionally, carbapenem resistance has been observed in 7% to 22.6% of Gram-negative isolates. The emergence of extended-spectrum beta-lactamases (ESBLs) and multidrug-resistant (MDR) microorganisms further complicates the treatment of Gram-negative bacterial infections. These findings highlight the need for continuous monitoring of antimicrobial susceptibility patterns and the development of effective hospital antibiotic policies to combat antibiotic resistance.
What is antimicrobial susceptibility testing?5 answersAntimicrobial susceptibility testing (AST) is a crucial component of antimicrobial stewardship, providing information on the effectiveness of antimicrobial drugs against bacterial isolates. It helps in guiding the appropriate treatment for bacterial infectious diseases and preventing the emergence and spread of antimicrobial resistance. AST methods and breakpoints are developed to determine the susceptibility of bacteria to specific antimicrobial agents. It involves testing the bacterial isolates against different antimicrobial drugs to assess their susceptibility. AST results can be interpreted to determine the most effective antimicrobial therapy for a particular infection. Genomic testing is also being explored for antimicrobial susceptibility prediction. AST is particularly important in the context of specific pathogens such as the Malassezia genus, which has been associated with various skin conditions and diseases like Crohn's disease and cancer. New methodologies, such as optical technology using Laser Speckle, are being developed to accelerate the AST process and provide faster results.
What is Antimicrobial susceptibility test?5 answersAntimicrobial susceptibility testing (AST) is a method used in clinical microbiology to determine the effectiveness of antibiotics against bacterial pathogens. It is based on the minimal inhibitory concentration (MIC), which is the lowest concentration of an antibiotic that inhibits the growth of the bacteria. AST plays a crucial role in guiding antimicrobial therapy and identifying new antibiotics. However, there are limitations to this approach, such as metabolic evasion (ME), where bacteria can survive antimicrobials by mechanisms like biofilms, intracellular growth, persisters, or dormancy. To address these limitations, new approaches have been developed, including automated systems like Clinical Antimicrobials Susceptibility Test Ramanometry (CAST-R), which accelerates AST and produces high-quality results. Additionally, novel assays performed in parallel with standard AST assays can provide additional resistance information and enable rapid reporting of results. Prioritizing quality assurance and control for AST is important in reducing the burden of antibiotic-resistant bacterial infections.
Antimicrobial susceptibility of klebsiella pneumoniae?3 answersKlebsiella pneumoniae is a pathogenic bacterium that is associated with various infections. Antimicrobial susceptibility testing is crucial for determining the effectiveness of antibiotics against this bacterium. Several studies have been conducted to evaluate the antimicrobial susceptibility pattern of Klebsiella pneumoniae. Tjandra et al. developed a machine learning workflow called MorphoAST, which uses single-cell morphological analysis to rapidly determine the susceptibility of Klebsiella pneumoniae to the antibiotic meropenem. Bayramnezhad et al. focused on studying the mutations of outer membrane porin in clinical isolates of Klebsiella pneumoniae. B et al. analyzed the changing trends in the isolation rate and antimicrobial susceptibility pattern of Klebsiella pneumoniae isolates from blood stream infections in both adult and pediatric patients. Maity et al. investigated the sensitivity pattern of Klebsiella pneumoniae isolated from various clinical specimens and found high resistance rates to several antibiotics, including ampicillin and ceftriaxone. Gautam et al. studied the prevalence of colistin-resistant Klebsiella pneumoniae in patients and their susceptibility pattern, highlighting the need for effective strategies to control the spread of antibiotic-resistant infections.
What assay is for antibacterial studies?2 answersIn vitro antimicrobial assessment of natural extracts or pure compounds involves the use of assays to evaluate their potential to kill or inhibit microbial growth in a laboratory setting. The Agar Well Diffusion and Disc Diffusion methods, Dynamic Contact assay, Thin-Layer Chromatography-Bioautography, Time-Kill assay and Biofilm assays, Microdilution methods and broth assays for Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC), Minimum Doubling Time/Growth Curve (MDT), Flow Cytofluorometric Assay and Bioluminescence Assay are commonly used for antibacterial studies.