β-lactam antibiotics (β-lactams) refer to a large class of antibiotics with a β-lactam ring in the chemical structure. Basically, all antibiotics including β-lactam nucleus in their molecular structure belong to β-lactam antibiotics, which is the most widely used class of existing antibiotics.
These include penicillin and its derivatives, cephalosporins, monoamide rings, carbapenems and penicillinase inhibitors, as well as newly developed cephamycins, thiomycins, monocyclic β-endo Amides and other atypical β-lactam antibiotics.
2. Beta lactam products
A. Penicillins: such as penicillin G, amoxicillin, ampicillin, and piperacillin. Before using penicillin antibacterial drugs, you must ask in detail whether you have a history of penicillin allergies, other drug allergies, and allergic diseases. Skin test, the concentration of skin test solution is generally 500U / ml. Once anaphylactic shock occurs, 0.1% epinephrine 0.5-1ml should be injected subcutaneously immediately, and there is no improvement in clinical performance. Repeat it 3-5 minutes later, and cooperate with other symptomatic rescue measures.
B. Cephalosporins: According to the antibacterial spectrum, antibacterial activity, stability to β-lactamase and renal toxicity, it is divided into four generations. The first generation: cefalexin, cefazolin, cefradine, cefadroxil; the second generation: cefaclor, cefuroxime, cefprozil, cefotiam, etc. According to the drug package, decide whether to conduct a drug allergy test. Those who are allergic to cephalosporins and those with penicillin anaphylactic shock or immediate reaction history are prohibited from this class of drugs.
C. New β-lactams
3. Beta lactamase
Beta-lactamase is a class of enzymes secreted by resistant bacteria against lactam antibiotics. It can be combined with beta-lactam ring to cleave beta-lactam ring and be destroyed, and lose antibacterial activity. It is the main reason for the resistance of these bacteria.
4. Beta lactam resistance
The first method of resistance is to use an enzyme to hydrolyze the β-lactam ring. By producing enzymes such as β-lactamase, bacteria can unravel the β-lactam ring in antibiotics, making antibiotics ineffective.
The genes for these enzymes may be on the bacterial chromosomes themselves, or they may be obtained by plasmid exchange. Its gene expression may begin after exposure to antibiotics.
The production of β-lactamase by bacteria does not mean that the use of any β-lactam antibiotics is ineffective. Sometimes β-lactam antibiotics can be used simultaneously with β-lactamase inhibitors.
However, you should think carefully before using β-lactam antibiotics against any bacteria suspected of producing β-lactamase. In particular, the use of β-lactam antibiotics may cause bacteria to produce β-lactamase. If the use of β-lactam antibiotics at the beginning of treatment leads to the production of β-lactamase, it will make it very difficult to use other β-lactam antibiotics thereafter.
The second resistance method changes the structure of the penicillin binding protein. β-lactam antibiotics do not bind strongly to these penicillin-binding proteins, so β-lactam antibiotics cannot destroy the bacterial cell wall. Methicillin-resistant Staphylococcus aureus uses this method to resist β-lactam antibiotics. This method of resistance also excludes the use of β-lactam antibiotics for treatment.
What is cefalexin?
Cephalexin belongs to β-lactam antibiotics and cephalosporins.
2. Mechanism of action
Its mechanism of action is to inhibit the cell wall synthesis of bacterial dividing cells by binding to one or more penicillin-binding proteins (PBPs) (cephalexin mainly binds to PBP-3), thereby playing an antibacterial effect. The antibacterial spectrum of cephalexin is similar to cephalosporin, but its antibacterial activity is worse than the latter. In addition to Enterococcus and methicillin-resistant Staphylococcus, Gram-positive cocci are sensitive to cephalexin.
Cefalexin has a good antibacterial effect against Neisseria, and has a low sensitivity to influenza bacilli. It has a certain antibacterial effect against some Escherichia coli, Proteus mirabilis, Klebsiella pneumoniae, Salmonella, and other Enterobacter bacteria, Acinetobacter, Pseudomonas aeruginosa and Bacteroides fragilis are resistant to cephalexin.
3. What is cephalexin used for?
Broad-spectrum antibiotics. Mainly used for Gram positive and negative bacterial infections, such as: influenza, hemorrhagic septicemia, streptococcosis, swine erysipelas, anthrax, emphysema, malignant edema, actinomycosis, necrotizing bacillus disease, hook end Septicemic fever (41-43 °C) or persistent low temperature (below 37 °C) caused by spirochete disease, indigestion, drinking cold water, sleeplessness, cripple walking, blue ears, tearing, etc.
At the same time, it is used to treat various inflammatory diseases, such as: infectious pleura pneumonia, pneumonia, atrophic rhinitis, blue ear disease, mastitis, hysteritis, stomatitis, urethritis and other cough and wheezing, difficulty breathing, low pregnancy, more stillbirths or death of piglets 7-10 days after birth, breast swelling, milk deterioration, decreased milk production, foot and mouth ulceration, salivation, sores and purulence.
The hazards of Cefalexin
1. Gastrointestinal reactions: nausea, vomiting, diarrhea and abdominal discomfort are more common gastrointestinal symptoms, occasionally pseudomembranous enteritis.
2. Nervous system reaction: A few patients may experience dizziness, diplopia, tinnitus, convulsions and other nervous system reactions.
3. Hepatotoxicity: A few patients may have transient liver dysfunction (temporal elevation of serum alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase) after administration.
4. Nephrotoxicity: A few patients may experience temporary increases in urea nitrogen, creatine, and creatinine, and occasional proteinuria and oliguria.
5. Blood system: Occasional drop in hemoglobin, thrombocytopenia, neutropenia, eosinophilia, etc. after medication.
6. Others: Long-term medication may cause microflora imbalance and double infection; vitamin K and vitamin B deficiency may also occur.
Features of Betalactam Cefalexin Test
1. 8min reading results
2. Detection limits respond to EU and US FDA norms
3. Single test for every target sample
4. Neither professionals nor equipment required
5. Eyes interpretation or quantitative measurement, suitable for lab and field use
6. Room temperature storage
7. Non-toxic and harmless
Detection Method of Betalactam Cefalexin Test
The Betalactam Cefalexin Test Kit is a colloidal gold immunochromatography assay that detects Beta-lactams, Cefalexin in egg and egg products and meets EU MRL. This kit can be applied for on-site rapid testing by various departments.
Samples for Betalactam Cefalexin Test
Samples include: egg, egg products.
Detection Limit of Betalactam Cefalexin Test
The LOD may change according to requirement or specimen's difference, please refer to kit instruction for further details.
Importance of Betalactam Cefalexin Test
Betalactam Cefalexin Test can help manufacturers, regulatory agencies, and the public monitor product quality and help humans protect their health.