Antimicrobial Susceptibility Testing (AST) & Antibiogram

TYPES OF ANTIBIOTIC RESISTANCE

Bacteria have evolved to survive in diverse environments. They survive exposure to harsh chemicals including antibiotics, and they also survive difficult growth conditions. They have learned to “detoxify” harmful substances e.g. antibiotics. Antibiotic resistance can either be intrinsic or acquired. INTRINSIC (INNATE) RESISTANCE Some bacteria are said to possess innate/intrinsic resistance against antibacterial action put […]

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Antibiotic Resistance / Antimicrobial Resistance (AMR), Antimicrobial Agents & Antibiotics, Antimicrobial Susceptibility Testing (AST) & Antibiogram, Pharmaceutical Microbiology, , , , ,

BRIEF HISTORY OF ANTIBIOTIC RESISTANCE

Antimicrobial agents, particularly antibiotics are the most significant class of pharmaceuticals and are one of the most influential medical inventions of the twentieth century. They have undeniably been a boon to human society in the fight against bacteria, saving millions of lives. Nonetheless, the number of infections caused by multidrug-resistant (MDR) bacteria is increasing across

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ANTIMICROBIAL (ANTIBIOTIC) RESISTANCE: definition, selective pressure and clonal selection

Antibiotic or antimicrobial resistance (AMR) is a phenomenon that occurs when bacteria are not killed or inhibited by usually achievable systemic concentration of an antibiotic (drug) with normal dosage schedule and/or fall in the minimum inhibitory concentration ranges of the drug in question. It is the ability of bacteria to resist the killing or inhibitory

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Chromatic Vancomycin Resistant Enterococci (VRE) agar

Chromatic VRE is a selective and differential chromogenic medium used for the qualitative and presumptive detection of vancomycin-resistant Enterococci directly from clinical samples. This medium is intended as an aid in the detection of the following bacteria: Enterococcus faecalis and Enterococcus faecium with acquired vancomycin resistance. Chromatic VRE agar is not intended to diagnose infection or

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Antibiogram & Interpretative Standards for Antibiotic (Antibacterial) Disks used for Susceptibility Studies

Antimicrobial Agents /Microorganisms  Disk Code  Disk Potency (µg)   Resistant   Intermediate   Susceptible Amikacin Enterobacteriaceae, P. aeruginosa Acinetobacter spp, Staphylococcus spp     AK 30     ≤14 15-16 ≥17 Amoxycillin-Clavulanic acid EnterobacteriaceaeStaphylococcus spp     Haemophilus spp AMC 20/10 ≤13 ≤19 ≤19   14-17 — —   ≥18 ≥20 ≥20 Ampicillin Enterobacteriaceae and Vibrio cholerae Staphylococcus spp   

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AUTOMATED SYSTEMS FOR BACTERIAL IDENTIFICATION AND ANTIBIOGRAM: VITEK 2 AUTOMATED COMPACT SYSTEM & MALDI-TOF

AUTOMATED SYSTEMS FOR BACTERIAL IDENTIFICATION AND ANTIBIOGRAM: VITEK 2 AUTOMATED COMPACT SYSTEM & MALDI-TOF There are several commercially available automated systems or computerized instruments and/or equipments that aid in the clinical/laboratory diagnosis of infectious diseases in the hospital especially as it relates to prompt and accurate identification of microbes. These automated systems also aid in

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PHENOTYPIC DETECTION METHODS OF ANTIMICROBIAL RESISTANCE (AMR) IN PATHOGENIC BACTERIA

The expression “phenotypic” is from the word phenotype, which means “the observable characteristics of an organism”. It describes the physical features of an organism in terms of its morphology, motility, colour and shape amongst other noticeable attributes that are typical to a particular organism. Thus, the phenotypic detection and characterization of antimicrobial resistant genes in

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OUTPUT OF ANTIMICROBIAL DRUG SUSCEPTIBILITY TESTING

The output of an antimicrobial drug susceptibility test is often expressed as raw data which are either expressed in the form of a zone size/diameter or minimum inhibitory concentration (MIC). The Clinical Laboratory Standard Institute (CLSI) formerly known as National Committee for Clinical Laboratory Standard (NCCLS) has published interpretation criteria for different antimicrobial agents. This

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Overview of antimicrobial susceptibility testing (AST) / Antibiogram

When a pathogenic microorganism is isolated from the specimen of a patient, the clinical microbiology laboratory will often carry out in vitro antimicrobial susceptibility testing (antibiogram) on the isolated pathogen in order to determine the antimicrobial susceptibility profile of the microbe to a range of antibiotics/drugs using antibiotic susceptibility disks, so that treatment can be

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Chromogenic culture media for detecting antimicrobial resistance mechanisms

Chromatic Super CAZ/AVI Chromogenic medium for detecting Ceftazidime-avibactam resistant Gram-negative bacteria. Chromatic Super CAZ/AVI is a selective and differential chromogenic medium used for screening ceftazidime-avibactam resistance in Enterobacterales and Pseudomonas aeruginosa. Chromatic Super CAZ/AVI is not intended to diagnose infection or guide therapy. Results can be interpreted after incubation for 18-24 hours. Subculture to a non-selective

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