This paper traces the history and development of some methods still in common use for routine ast, e. The significance of the intermediate category of the singledisk diffusion test kirby bauer of antibiotic susceptibility has never been clearly defined. The microbroth dilution method has become more widely used due to its ability to become automated, however, the kirby bauer. In the virtual kirby bauer exercise, one of three randomized kirby bauer assay plates are presented, containing staphylococcus aureus, escherichia coli, or pseudomonas aeruginosa that have been tested for susceptibility to different antibiotics. Interpretation of zones of inhibition in mm for kirby bauer antibiotic susceptibility test. The disk diffusion test, or agar diffusion test, or kirbybauer test is a test of the antibiotic sensitivity of bacteria.
The diameter of zone of inhibition must be measured and result read from the kirby bauer chart as sensitive, intermediate or resistant. The introduction of various antimicrobials for treating variety of infections showed the necessity of performing antimicrobial susceptibility testing as a routine procedure in all microbiology laboratories. The kirby bauer or disk diffusion test is used to determine if an organism is susceptible or resistant to a selection of. Jun 01, 20 kirbybauer disk diffusion susceptibility test for antibiotics, disinfectants and antiseptics the disk diffusion technique is used to determine the antibacterial activity of antibiotics and disinfectants. Antibiotic susceptibility pattern of klebsiella pneumoniae. Turck i n the words of the authors, the paper by a. The disk diffusion test, or agar diffusion test, or kirby bauer test discdiffusion antibiotic susceptibility test, discdiffusion antibiotic sensitivity test, kb test, is a test of the antibiotic sensitivity of bacteria. Rapid, modified kirbybauer susceptibility test with. The kirby bauer test, or disk diffusion test, is a standard tool to measure the. Kirbybauer antibiotic sensitivity biology libretexts. Disc diffusion techniques are used by most laboratories to test routinely for antimicrobial susceptibility. Singledisk diffusion testing kirbybauer of susceptibility. This type of test, generally described as antimicrobial susceptibility testing ast, is commonly performed in a clinical laboratory.
A rapid 67 hr, modified kirbybauer disk susceptibility method, by which derivatives of tetrazolium dyes are used to enhance delineation between areas of growth and zones of inhibition, has been developed. The isolated strains were subjected to antibiotic susceptibility testing. Rapid, modified kirbybauer susceptibility test with single. Approved standard 9th edition, represents the standard for clinical laboratories performing susceptibility testing today. The validity of this carefully standardized technique depends on, for each defined species, using discs of correct antimicrobial content, an inoculum which gives confluent growth, and a reliable mueller hinton agar. A rapid 67 hr, modified kirbybauer disksusceptibility method, by which derivatives. Testing the effectiveness of antimicrobial drugs against specific organisms is important in identifying their spectrum of activity and the therapeutic dosage.
Singledisk antibioticsensitivity testing of staphylococci. The disc diffusion method was originally described in 1966, and is well standardized and has been widely evaluated. This method relies on the inhibition of bacterial growth measured under standard conditions. Kirby bauer nccls modified disc diffusion technique. Antibiotic susceptibility pattern of urinary isolates in imphalmanipur. Antibiotic resistance increasing concern over antibiotic resistant organisms morbidity and mortality despite a wide array of antibiotics rapid antimicrobial susceptibility testing ast should help improve antibiotic use and patient outcomes. Susceptibility studies of these organisms were made according to the kirby bauer method, using two mediamuellerhinton and the oxoid sensitivity test medium. Mostly, fresh subcultures are used and filter paper disks impregnated with a standardized concentration of antimicrobial agents are placed on the surface and the zone of inhibition. The techniques employed are often taken for granted. Welcome to microbugz antimicrobial susceptibility test. Get a printable copy pdf file of the complete article 1.
It was the purpose of our study to evaluate this method as a standard technic. The kirby bauer antimicrobial susceptibility test can be modified to provide students the opportunity for enhanced learning by comparing their data and discussing the ramifications of their results. Antimicrobial susceptibility testing, drug resistance. Using the virtual ruler the mouse, the diameter of each zone of inhibition can be measured. So if you havent heard about the lectures before, we have defined the methods, we have introduced them. Lecture 9 antimicrobial susceptibility testing disk. Kirby bauer testing measures sensitivity of bacteria to antibiotics by culturing bacteria on solid growth media surrounding sources of drug. Bauer kirby disk diffusion this is one of the more commonly used methods of antimicrobial susceptibility testing. Identification and susceptibility testing bd bbl disc diffusion bd bbl sensi disc antimicrobial susceptibility test discs bd bbl cefinase paper discs bd bbl prompt inoculation system bd bbl sensi disc antimicrobial susceptibility test discs for veterinary laboratory use. If the organism is susceptible to a specific antibiotic, there will be no growth around the disc containing the antibiotic.
But the kb is still used in some some labs, or used with certain bacteria that automation does not work well with. Use of media other than muellerhinton agar may result in erroneous. Bd bbl sensidisc antimicrobial susceptibility test. Evaluation of antibiotic susceptibility test results. Antimicrobial susceptibility testing, drug resistance mechanisms, and therapy of infections with nontuberculous mycobacteria october 03, 2012 summary moreover, the clinical and laboratory standards institute clsi has published and recently in 2011 updated recommendations including suggested antimicrobial and susceptibility breakpoints. Historically, in vitro susceptibility testing was routinely performed by disk diffusion kirby bauer method. A comparison of disc diffusion and microbroth dilution. This is a method to determine the sensitivity of microorganisms to specific antimicrobial drugs. Antimicrobial susceptibility testing was carried out by means of kirbybauer. Kirby bauer antibiotic testing also called kb testing or disk diffusion antibiotic sensitivity testing uses antibiotic containing wafers or disks to test whether particular bacteria are susceptible to specific antibiotics. First, a pure culture of bacteria is isolated from the patient. It relies on the diffusion of the antibacterial agents into the agar surrounding the disks. My name is lina cavaco and this lecture is focused on antimicrobial susceptibility testing with disk diffusion. The results of a susceptibility test must be interpreted by the laboratory prior to communicating a report to a patients physician.
The kirby bauer test, or disk diffusion test, is a standard tool to measure the effectiveness of antibiotics against pathogens. The methods of antimicrobial susceptibility testing are divided into types based on the principle of testing involved, 1 diffusion. In this test, wafers containing antibiotics are placed on an agar plate. It has been superseded in clinical labs by automated tests. Pdf singledisk diffusion testing kirbybauer of susceptibility of. The clsi susceptibility testing document lists groups of some antimicrobial agents with nearly identical activities that can provide practical alternatives for testing. For example, most recently, the wvdl has begun antimicrobial.
It uses antibiotic discs to test the extent to which bacteria are affected by those antibiotics. Kirby bauer antibiotic sensitivity student health center. The disk diffusion method given by kirby bauer is a standardized technique for testing rapidly growing pathogens. Additionally, the modified test has demonstrated reproducibility comparable to the standard kirby bauer test. Disk diffusion by the kirby bauer method is a standardized technique for testing rapidly growing pathogens. They also highlighted the fact that different bacterial species have different susceptibilities to the same antibiotic, and that there is no international agreement on breakpoints for interpretation of antimicrobial susceptibility tests. These tests can be useful for screening isolates to categorize them as susceptible, intermediate, resistant, or non. Modifying the kirbybauer antibiotic susceptibility exercise.
Antimicrobial susceptibility testing was carried out by means of kirby bauer. Diameter of zone of inhibition zoi antibiotic disk conc. Susceptibility testing of individual isolates is important with species that may possess. Experiences with the kirbybauer method of antibiotic. Purpose the purpose of the kirby bauer disk diffusion susceptibility test is to determine the sensitivity or resistance of pathogenic aerobic and. It is demonstrated that the modified test is applicable to susceptibility determinations with representative, commercially available antimicrobial disks. In this section, we will discuss common methods of testing the effectiveness of antimicrobials. Kirby bauer test for antibiotic susceptibility the kirby bauer test for antibiotic susceptibility, called the disc diffusion test, is a standard that has been used for years.
The size of the growthfree zone determined whether the bacterium was considered to be susceptible, resistant, or intermediate to a particular antibiotic. Kirbybauer disk diffusion susceptibility test protocol, inoculation of the muellerhinton agar plate. Muellerhinton agar mha is the standard medium recommended in guidelines. Kirby bauer method of antimicrobial susceptibility testing main menu description. History and development of antimicrobial susceptibility. Testing the effectiveness of antimicrobials microbiology. The kirby bauer test, known as the diskdiffusion method, is the most widely used antibiotic susceptibility test in determining what choice of antibiotics should be used when treating an infection. The disk diffusion dd test, or kirby bauer procedure, is a simple and inexpensive method for screening a large number of isolates to determine the antimicrobial susceptibility. Thirtytwo percent of 756 clinical isolates of proteus mirabilis were of intermediate susceptibility to chloramphenicol, a higher percentage than for any other species. Pdf a new twist to the kirbybauer antibiotic susceptibility test. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext.
The test determines the susceptibility of a microbial species against different antibiotic agents. Antimicrobial susceptibility testing ast types and. Antibiotic susceptibility pattern of klebsiella pneumoniae isolated from sputum, urine and pus samples 1dr. It uses antibiotic discs to test the extent to which. Single colony was selected and emulsified in 3ml sterile normal saline solution in a sterile test tube.
Kirbybauer disk susceptibility test biology libretexts. The evaluation of the classical kirbybauer antibiogram method for. Dilution methods or antimicrobial gradient strips can be used to. The introduction of various antimicrobials for treating variety of infections showed the necessity of performing antimicrobial susceptibility testing as a. In keeping up with the most current testing methodologies, the wvdl primarily uses the broth microdilution method for antimicrobial susceptibility testing, although the kirby bauer method is still employed when needed. The disk diffusion dd test, or kirby bauer procedure, is a simple and inexpensive method for screening a large number of isolates to determine the antimicrobial susceptibility in many clinical laboratories. Seven organisms were selected and tested against 23 highpotency antimicrobial agents. Produced by center for translational science education at tufts university school of medicine as part of the infectious disease high school curriculum.
It is affected by many factors among which are the media used. The performance of antimicrobial susceptibility testing by the clinical microbiology laboratory is important to confirm susceptibility to chosen empirical antimicrobial agents, or to detect resistance in individual bacterial isolates. Hardydisk antimicrobial sensitivity test ast intended use hardydisktm ast disks are used for semiquantitative in vitro susceptibility testing by the agar diffusion test procedure kirby bauer of rapidly growing and certain fastidious bacterial pathogens. The performance of antimicrobial susceptibility testing by the clinical. Modified kirbybauer disc diffusion method for antimicrobial. Measuring drug susceptibility boundless microbiology. Antimicrobial susceptibility testing by clsi method.
The purpose of the kirby bauer disk diffusion susceptibility test is to determine the sensitivity or resistance of pathogenic aerobic and facultative anaerobic bacteria to various antimicrobial compounds in order to assist a physician in selecting. The kirbybauer test, known as the diskdiffusion method, is the most widely used. Bauer, then standardized by the world health organization in 1961. Muellerhinton agar mha is the best medium to use for routine antimicrobial susceptibility testing using kirby bauer disc diffusion method for nonfastidious bacteria both aerobe and facultative anaerobe. Modified kirby bauer disc diffusion test method is a reference method which could be used as a routine technique to test the sensitivity of the isolate in the clinical laboratory. A disc of blotting paper is impregnated with a known volume and appropriate concentration of an antimicrobial, and this is placed on a plate of susceptibility testing agar uniformly inoculated with the test. In this test, small filter paper disks 6 mm impregnated with a standard amount of antibiotic are placed onto an agar plate to which bacteria have been swabbed. Terms in this set 21 name 4 broad methods of testing invitro susceptibility. Jun 17, 2016 antibiotic susceptibility testing, 2015. Meningitis lab manual antimicrobial susceptibility. Rapid antimicrobial susceptibility testing ifl quarterly webinar december 10, 2019 associate professor of pathology university of utah school of medicine medical director, bacteriology and special microbiology labs arup laboratories mark fisher, phd, dabmm. Antimicrobial susceptibility testing by the disc diffusion method is discussed with emphasis on the need for standardization of methodology.
Some organisms may be completely resistant to a specific antimicrobial while others are highly susceptible. Microbiology guide to interpreting minimum inhibitory. Kirbybauer susceptibility testing flashcards quizlet. It measures the effectiveness of antibiotics on bacteria and aids in proper physician administration of the correct antibiotic. Two of the different types of antibiotic susceptibility tests available are the solid media based kirby bauer method and the liquid media based microbroth dilution method. Kirby bauer disk diffusion method flipped lab videos. Jan 11, 2019 the selection of an appropriate antimicrobial is a challenging task for clinicians.
Jan 17, 2016 kirby bauer disk diffusion method flipped lab videos. The isolates were found to be highly resistant to penicillin g. First developed in the 1950s, it was refined and by w. In this approach, the classical kirbybauer antibiogram. The kirby bauer disk diffusion method is one of the most widely practiced antimicrobial susceptibility tests ast. In order to eliminate or minimize variability in this testing, bauer et al. The active learning helps students to identify and correct several common misconceptions. Antimicrobial susceptibility testing ast is performed daily on bacterial isolates in clinical laboratories. Antimicrobial susceptibility testing is a standardized method. A serial twofold dilution of antibiotic are made in test tubes from 0 to maximum concentration that is achieved in.
A crosssectional study was conducted antibiotic susceptibility pattern of s. The kirby bauer test for antibiotic susceptibility also called the disc diffusion test is a standard that has been used for years. Antimicrobial susceptibility testing by the kirbybauer disc diffusion. Show full abstract method according to the unified protocol. Interpreting the results of the bauer kirby method of antibiotic susceptibility testing. Kirbybauer disk diffusion susceptibility test protocol asm. History and development of antimicrobial susceptibility testing. Staphylococcus aureus and its antimicrobial susceptibility.
Interpretation of zones of inhibition in mm for kirbybauer antibiotic susceptibility test. Dec 01, 2009 emergence of antimicrobial resistance and the rationale for performing susceptibility testing. Antimicrobial activity evaluation and comparison of. An assortment of routine susceptibility test methods can be performed, including the disk diffusion bauer kirby test, an antibiotic strip gradientdiffusion method e test, agar dilution with a mechanized inoculator, broth macrodilution or microdilution, and a shortincubation automated instrument method 12 see chapter 286. The disk diffusion test, or agar diffusion test, or kirbybauer test discdiffusion antibiotic susceptibility test, discdiffusion antibiotic sensitivity test, kb test, is a test of the antibiotic sensitivity of bacteria. Approved standard 9th edition, represents the standard. A standardized inoculum is spread on an agar plate.
Standardized methods for agar diffusion testing have been. Dec 08, 2009 protocol pdf the kirbybauer disk diffusion susceptibility test determines the sensitivity or resistance of pathogenic bacteria to various antimicrobial compounds in order to assist physicians in selecting treatment options their patients. Pdf antibiotic sensitivity and the effect of temperature on microbial growth are two standard laboratory activities found in most microbial laboratory. The kirby bauer test for antibiotic susceptibility, called the disc diffusion test, is a standard that has been used for years. However, these guidelines are not strictly adhered to in. Different antimicrobial agents have different effects on different organisms. Disk diffusion test bauerkirby procedure linear regression. Antimicrobial susceptibility testing for polymyxins. Kirbybauer disk diffusion susceptibility test for antibiotics, disinfectants and antiseptics the disk diffusion technique is used to determine the antibacterial activity of antibiotics and disinfectants. Join researchgate to discover and stay uptodate with the latest research from leading experts in antimicrobial susceptibility. Thirtytwo percent of 756 clinical isolates of proteus mirabilis were of intermediate susceptibility to chloramphenicol, a. Antimicrobial susceptibility test kirbybauer method quizlet. Inoculate the plate with the test organism by streaking the swab in a backandforth motion very close together as you move across and down the plate.