The rational use of antimicrobial drugs is a basic requirement of the Ministry of Health for clinicians, and how to do so is an important challenge. In order to effectively carry out anti-infective treatment while avoiding misdiagnosis and misdiagnosis, clinicians must conduct detailed consultation and efficacy observation of patients, try to obtain bacteriological examination evidence, master the correct method of administration, and adjust the treatment plan in a timely manner to improve the effectiveness of antibacterial.
I. Determine the pathogen and lesion site
1. Determine the type of pathogenic bacteria of infection
The common clinical pathogens are viruses, bacteria, fungi, protozoa, mycoplasma and chlamydia 5 categories, determine the type of pathogens is necessary for the correct selection of antibacterial drugs. If the patient has a normal white blood cell count, normal or decreased neutrophil ratio and increased lymphocyte or monocyte ratio, the patient may be infected with tuberculosis, mycoplasma, chlamydia or virus; and protozoan infections often have eosinophilia.
Inflammation of the body is mostly caused by infection, but it can also be caused by non-infectious inflammation (such as connective tissue disease, subacute or chronic thyroiditis, infarction and necrosis of the body tissue), which is easily confused with infectious fever. Chronic fever is mostly caused by connective tissue disease, also seen in hyperthyroidism or drug fever, etc.; persistent high fever should pay attention to the possibility of leukemia, lymphoma and other diseases, and the bone marrow examination has abnormal findings.
2.Define the site of infection
1.Lung infection
Patients often present with cough, coughing sputum, chest pain and dyspnea. The characteristics of sputum are helpful in determining the type of infection. Yellow pus sputum mostly suggests Gram-positive cocci infection; brown-red jelly-like sputum suggests Klebsiella pneumoniae infection; light green sputum suggests Pseudomonas aeruginosa infection; pus-smelling sputum suggests anaerobic bacteria infection. Intense cough with little sputum suggests mycoplasma or chlamydia infection in patients.
2. Intestinal infection
Patients are mostly accompanied by abdominal pain and diarrhea. Stool properties help to diagnose, dilute stools suggest enteritis; pus and blood stools suggest bacterial dysentery; rice water-like stools suggest cholera. Biliary tract infection is mostly accompanied by right upper abdominal pain and jaundice, and hepatobiliary ultrasonography shows corresponding changes of bile duct and gallbladder.
3.Urinary system infection
Patients mostly have urinary frequency, urinary urgency, urinary pain and other signs of urethral and bladder irritation, which may be accompanied by low back pain or soreness and swelling. Patients’ routine urine examination may show a significant increase in the number of white blood cells and bacteria.
4.Gynecological infection
Patients are mostly seen in women of childbearing age, mostly with lower abdominal pain, excessive leucorrhea, and pelvic ultrasound showing inflammatory masses around the adnexa or pelvic effusion.
Second, the correct way to administer the drug
1. Dosage
When using antibacterial drugs, it is important to ensure that the daily dose is within the effective dose in order to produce a better antibacterial effect.
2.Method of administration
At present, local application of antibacterial drugs is not recommended, general infections can be given oral antibacterial drugs, more serious infections can be given intravenous drip, intravenous drugs must pay attention to the choice of liquid dissolved drugs.
3.Daily dosing frequency
According to pharmacokinetic and pharmacodynamic characteristics, commonly used antibacterial drugs are divided into two categories: time-dependent drugs and concentration-dependent drugs.
1.Time-dependent drugs
The antibacterial effect is related to the duration of the effective concentration of the drug and bacterial contact, and the daily dosing is conducive to maintaining the effective concentration of antibacterial drugs in blood and body fluids.
2.Dose-dependent drugs
The antibacterial effect is related to the highest drug concentration of bacterial exposure, and once daily dosing is beneficial to increase the highest concentration of antibacterial drugs in blood and body fluids.
3.Drug allergy skin test
Penicillins and cephalosporins are prone to allergic reactions in the process of use, which may even lead to death of patients, so patients must be carefully asked whether they have a history of allergy to penicillins and cephalosporins before use. Cephalosporins and penicillins have some cross-allergic reactions, so those who have a history of penicillin anaphylaxis are prohibited to use cephalosporins.
Third, individualized drug use
1.The choice of intensity
For patients with mild disease, the commonly used antimicrobial drugs can be selected, and if the efficacy is not good, then change to the antimicrobial drugs with broad antimicrobial spectrum and strong effect, which is called ascending ladder treatment; for patients with severe disease, if the preferred antimicrobial drug treatment is ineffective will lose the time of treatment and endanger life, so first use the antimicrobial drugs with broad antimicrobial spectrum and strong effect, and after the condition improves, change to penicillin or cephalosporin antimicrobial drugs, which This is called step-down therapy.
2.Course of treatment
The duration of clinical use of antibacterial drugs varies slightly.
① The general treatment time is 3~7 days;
② The antimicrobial drug must be changed if the infection cannot be controlled in 3 days;
③ For those who have been effectively treated for 1 week and have not been in complete remission, the course of medication can be extended to 2 weeks;
④ Except for a few special infections, it is not recommended to use one antimicrobial drug for more than 2 weeks.
Fourth, the empirical treatment to scientific treatment
For patients with severe or long-term persistent infections, bacterial culture and drug sensitivity tests should be performed by taking specimens to identify the pathogenic bacteria and their sensitive drugs.
Bacterial culture and drug susceptibility testing requires 3-5 days to produce results, and the positive rate of bacteriological examination is low, so usually the antimicrobial drugs are first selected based on clinical experience, while the specimens are kept for bacteriological examination. When the empirical treatment is ineffective, antimicrobial drugs can be selected again for treatment based on the results of the bacteriological examination.
Currently, the application of antimicrobial drugs is an effective way to fight bacterial infections. In addition, attention must be paid to improving the patient’s general condition, detecting and removing septic foci of infection, and combining with symptomatic treatment and other comprehensive measures in order to achieve a cure.
In addition, the choice of antimicrobial drugs for special populations must also be taken into account.
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Selection of antimicrobial drugs for special groups
1. People with reduced kidney function
When using antimicrobial drugs excreted mainly by the hepatobiliary system or by both the kidney and the hepatobiliary system, maintain the original treatment amount or slightly reduce the dose;
When using antimicrobial drugs that are mainly excreted by the kidney and are not nephrotoxic or only mildly nephrotoxic, the dose must be adjusted appropriately;
Avoid the use of nephrotoxic antibacterial drugs.
2.People with decompensated liver function
Liver disease can be applied normally to drugs mainly cleared by the liver, liver function must be closely monitored;
Avoid the use of drugs that are mainly cleared or metabolized by the liver in patients with decompensated liver function;
The use of antibacterial drugs cleared by both hepatic and renal routes must be reduced.
3. Elderly patients
In particular, elderly patients should reduce the dosage of drugs that are mainly excreted by the kidney according to the mild renal decompensation;
It is advisable to use antimicrobial drugs with low toxicity and bactericidal effect, and avoid using antimicrobial drugs with high toxicity.
4.Pregnant and lactating women
Avoid the application of drugs that have teratogenic or obvious toxic effects on the fetus or mother, and when there are indications for their application, they should be used under blood concentration monitoring to ensure their safe and effective use;
Choose antibacterial drugs with low toxicity, no obvious effect on the fetus and mother, and no teratogenic effect;
When using any antibacterial drugs, it is advisable to suspend breastfeeding.
5.Neonates and pediatricians
Avoid using antibacterial drugs with high toxicity (nephrotoxicity, ototoxicity) or serious adverse reactions (affecting dental and bone development); if there are indications for their use, blood concentration monitoring should be performed and the patient’s drug regimen should be adjusted accordingly;
Neonates should be given a reduced dose of drugs that are mainly excreted through the kidneys to avoid central nervous system toxic reactions.