How to interpret the bacteriological drug sensitivity test report.

First, the concept of normal microbiome 1, normal microbiome: in the human body table and with the outside world in the mouth, nasopharyngeal, intestines, urinary tract and other cavity inhabited by microorganisms, in normal circumstances harmless and beneficial to the host, such microorganisms for the normal microbiome, which is mainly bacteria, commonly known as normal microbiome.
2, normal bacteria in various parts of the human body II, pathogenic bacteria classification pathogens refers to the host can invade the infection caused by microorganisms, including bacteria, fungi, viruses and so on.
Pathogens are classified as pathogenic as follows: pathogenic bacteria (less variety, strong toxicity) and conditional pathogenic bacteria (many species and increasing, weak toxicity) are often clinically mixed with pathogenic bacteria and pathogenic bacteria.
but the former clearly contains a wider range than the latter, or the commonly referred pathogenic bacteria are generally referred to as broad concepts.
3. Conditional pathogenic bacteria and bacterium disorders 1, conditional pathogenic bacteria: some bacteria are not disease-like under normal circumstances, when certain conditions change in special circumstances can cause disease, such bacteria are called conditional pathogenic bacteria or opportonopathic bacteria.
these specific conditions are roughly the following: changes in the site of residence, low immune function, bacteriological disorders.
2, bacteria disorders: is the host site of the normal bacteria between the proportion of various types of bacteria have changed significantly and beyond the normal range of the state.
resulting series of manifestations, called bacterial disorders or bacterial alternating disorders.
3. The main characteristics of pathogenic bacteria (1) weak or non-obvious toxicity; (2) often drug-resistant bacteria or multi-drug-resistant bacteria; (3) the object of infection is long-term use of antibiotics, the body's immune function decreased patients.
4, the condition of pathogenic bacteria of several identity (1) pathogens: will reproduce in the host body and invade or destroy tissue, causing infection of microorganisms.
patients caused by this type of bacteria infection, with bacteria reported the antibiotics suggested treatment, the effect is obvious.
(2) planted bacteria: (planted: bacteria or fungi settled in a part of the human body to form a relatively stable parasitic state, will not be with the external mechanical impact and completely leave the original place of residence.
) microorganisms that reproduce in the body but do not invade or destroy tissues.
the following phenomena suggest that the reported bacteria are implantable bacteria: (1) treated with antibiotics as suggested by the bacterial report, the bacteria disappear, and the symptoms of infection persist.
(2) Because of the pan-resistant bacteria, clinical experience combined medication, infection symptoms improved, but the bacteria still exist.
(3) contaminated bacteria: bacteria in non-infected areas are contaminated during the retention of specimens.
treatment is not effective, multiple tests can be excluded.
4. The concept of pathogenic bacteria 1, pathogenic bacteria: patients have typical symptoms of infection;
2, pathogenic bacteria and disease-d'ethliogenic differences: the ability of pathogenic bacteria to attack the human body is much greater than the condition of pathogenic bacteria.
V. Drug sensitivity test 1, concept: the method of determining whether anti-infective drugs have antibacterial or bactericidal effects on pathogenic microorganisms in-body is called drug sensitivity test, referred to as drug sensitivity test.
2, purpose: to detect the sensitivity of bacteria that may cause infection to one or more antimicrobials.
3, the results of the judgment standard: At present, China's drug sensitivity test judgment standard refers to the CLSI standard document, CLSI document is China's Ministry of Health issued documents.
, MIC (minimal inhibitory concentration, minimum antibacterial concentration) 1, concept: refers to the in vitro test, antibacterial drugs can inhibit the growth of bacteria in the medium of the minimum drug concentration.
is an indicator of antimicrobial activity of antimicrobial drugs, showing the drug's ability to suppress pathogenic microorganisms.
2, CLSI document on the definition of sensitivity, intermediary, drug resistance Test strip network sensitive: the highest blood drug concentration of 4 times MIC, effective using conventional doses;
, antibiotic egalitivity and antimicrobial spectrum 1, antibiotic egalition: refers to the use of a related antibiotic test results to predict the antibacterial activity of similar antibiotics.
cephalosporine is equivalent to other generations of cephalosporine, and the results of cephalosporine can be used to predict the other generation of cephalosporine.
this feature allows the detection of a few antibiotics without affecting the wide clinical selection of other antibiotics.
2, antibacterial spectrum: refers to the bacteria in the "wild bacteria" state can be inhibited by antibiotics in the body when the effective concentration.
these bacteria are called naturally sensitive bacteria to the antibiotic.
that are not listed in the antimicrobial spectrum are naturally resistant bacteria.
8, bacterial resistance 1, bacterial resistance: is the bacteria against antibacterial drugs sterilization, antibacterial action of a defense, a biological ideosis.
2, natural resistance (inherent resistance): resistance is an inherent characteristic of a bacterium called the natural or inherent resistance of bacteria.
natural resistance is very stable, which can predict whether a particular bacteria or possible bacteria are resistant to a particular antibiotic.
3, access resistance: because bacteria obtain drug-resistant genes, so that the original sensitive bacteria into drug-resistant so-called bacteria access resistance.
drug resistance is the most important drug resistance problem facing the clinic.
is made resistant by mutations in naturally sensitive bacteria genes or by obtaining a gene fragment that alters their genotypes.
drug-specific drug resistance is constantly changing (the frequency of which is related to antibiotic applications) and cannot be predicted and requires drug sensitivity testing.
, drug sensitivity test report interpretation of several questions 1, drug sensitivity test report S, I, R refers to what?S (susceptible) refers to bacterial antimicrobial sensitivity, the average blood concentration at regular doses is more than 5 times more than MIC, the conventional dose is usually effective;
2, bacterial drug sensitivity test is determined?Based on the Paper Diffusion Method (Kirby-Bauer Method) recommended by the National Committee for Clinical Laboratory Standards (NCCLS).
will contain a certain amount of antibacterial drugs on the surface of the agar plate coated with bacteria, 35 degrees C culture overnight, measuring the size of the anti-bacterial circle around the paper to determine the sensitivity of bacteria to the drug, the larger the anti-bacterial circle the higher the sensitivity.
different bacteria have different criteria for determining the sensitivity of different antimicrobials, such as cephalosporine the antibacterial ring of E. coli bacteria is R, 15mm-22mm is I, 23mm is S;
3, drug sensitivity test, test antibacterial drug varieties are selected? There are nearly 200 kinds of antimicrobial drugs, drug sensitivity tests do not need and can not include each antimicrobial.
the types of antimicrobial tablets tested were determined on the basis of the sensitivity of various bacterial antimicrobials and the drugs that may be clinically available, and similar drugs usually selected only 1-2 representative varieties.
NCCLS recommends drug varieties that should be tested in drug-sensitive trials of various bacteria, such as staphylococcus genus, which should include benzodiacin, penicillin, erythromycin, Klinmycin, compound sulfonamide metformin (SMZ-TMP) and vancomycin;
4, why is enterococcal genus bacterial drug sensitivity reported so few assay drugs? Natural resistance to cephalosporins and a variety of antimicrobial drugs, so the drug sensitivity test includes fewer types of antibacterial drugs, NCCLS recommended test varieties are ampicillin or penicillin, vancomycin (de-metformin), in addition to adding gyromycin, chloramphenicol, erythromycin, lymphocycin, epoxycin and furantoin, etc., the 20th suitable for urine specimens.
5, bacteria are sensitive to a variety of antimicrobial drugs. How do I choose the most effective drug? Antibacterial drugs should be selected according to the site of infection, the severity of the disease, the antibacterial effect of the drug and the characteristics of pharmacodynamics.
6, are all positive cultures clinically significant? Not all positive cultures are real pathogens, the reasons may be: (1) the reported bacteria are contaminated bacteria, the clinical significance of bacterial culture results is related to the samples taken, such as joint fluid, chest fluid, blood and other sterile specimens are more clinical significance, but even if the blood culture is positive may be contaminated bacteria, it is reported that a single blood culture coagulase-negative staphylococcus, streptococcus, enterococcal positive, the probability of contamination is 85 percent.
some specimens are susceptible to contamination such as sputum specimens are easily contaminated by bacteria carried in the throat, urine culture is susceptible to urethra, urethra and urethra bacteria contamination.
(2) May be the application of antibacterial drugs after the bacterial group alternating, especially when the original plural bacterial infection, for the advantage of bacteria treatment after a period of time may not be superior to the advantage of bacteria, broad-spectrum antimicrobial treatment may appear fungal infections, so the use of antimicrobials for a longer period of time infection, the course of treatment needs to review bacterial culture.
In addition, there are many factors affecting clinical efficacy, it is reported that the drug-sensitive test results and clinical efficacy of the compliance rate of about 70%, so bacterial culture and drug-sensitive trial reports can only be used as a reference for clinical drug use, should be based on the patient's post-drug treatment response and clinical conditions to adjust the use of drugs.
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