Tetracyclines bacterial infections

The discovery and production of antibiotics has been of tremendous importance to human and animal health care. Prior to their discovery about half a century ago, many bacterial infections caused debilitating diseases and fatalities were high. The discovery of antibiotics was a major step in the treatment of infectious diseases, especially those caused by bacteria. Today about 50,000 tonnes of antibiotics are produced annually. About a third of this consists of penicillins, whilst tetracyclines make up about a quarter of the market. 

Tetracycline and its derivative doxycycline are antibiotics widely used in the treatment of bacterial infections. They also exert an antimalarial activity. Tetracyclines inhibit the binding of aminoacyl-tRNA to the ribosome during protein synthesis. 

ORAL ADMINISTRATION. To control the infectious process or prevent a bacterial infection, the nurse must keep several important things in mind when administering the tetracyclines, macrolides, and lincosamides. 

Systemic therapy with a variety of (3-lactams, macro-lides and lincosamides (clindamycin) has been the cornerstone of skin infection therapy for many years [17]. However, topical antibiotics can play an important role in both treatment and prevention of many primary cutaneous bacterial infections commonly seen in the dermatological practice [18], Indeed, while systemic antimicrobials are needed in the complicated infections of skin and skin structure, the milder forms can be successfully treated with topical therapy alone [18], The topical agents used most often in the treatment of superficial cutaneous bacterial infections are tetracyclines, mupirocin, bacitracin, polymyxin B, and neomycin. 

Cystitis is a condition where urinary tract bacterial infection is presented. Products recommended as first-line of treatment include amoxicillin, oral cephalosporin, trimethoprim or nitrofurantoin. Doxycycline is a tetracycline antibacterial agent whereas itraconazole is an antifungal agent. 

Since 1969, the Food and Drug Administration s Center for Veterinary Medicine (formerly the Bureau of Veterinary Medicine) has had cause for concern that the subtherapeutic use of antibiotics in animal feeds may cause bacteria in animals to become resistant to antibiotics. This resistance to antibiotics is said by many knowledgeable scientists to be transferred to bacteria in humans, thus making these antibiotics ineffective in treating human bacterial infections due to compromise of therapy. For this reason, FDA proposed in 1977 to withdraw the use of penicillin in animal feed and restrict the use of the tetracyclines (chlortetracycline and oxytetracycline) to certain uses in animal feed. This talk will focus on FDA s efforts to finalize its review of the issue and present an update on the current status of the 1977 proposals. 

Antibiotics. The history of antibiotics is one of remarkable success in saving lives. Penicillin, although discovered earlier, began to be manufactured for sale as a drug in 1942. Tetracycline followed in 1955 and amoxicillin in 1981. These, other variants developed over the years, and some new recent classes of antibiotics treat bacterial infections by killing the bacteria or preventing them from multiplying. In the process, they save lives and speed recovery. Except for some products sold for external use, antibiotics require a prescription. 

Tetracycline antibiotics -cycline Tetracycline, doxycycline Bacterial infections (33)... 

D. Treatment of bacterial infections Antibiotics that selectively affect bacterial function and have minimal side effects in humans are usually selected to treat bacterial infections. Rifampicin, which inhibits the initiation of prokaryotic RNA synthesis, is used to treat tuberculosis. Streptomycin, tetracycline, chloramphenicol, and erythromycin inhibit protein synthesis on prokaiyotic ribosomes and are used for many infections. Chloramphenicol affects mitochondrial ribosomes and must be used with caution. 

Antibiotics Treatment of bacterial infections Sulfamethoxazole, trimethoprim, tetracycline, ciprofloxacin 19, 23, 27, 33... 

Tetracyclines were the first broad-spectrum antibiotics and have been used successfully for decades to treat both gram-positive and gram negative bacterial infections (82). Chlortetra-cycline was the first tetracycline to be isolated, in 1948, from Streptomyces aureofaciens (83). Other common tetracyclines, such as oxytet-racycline and tetracycline, were isolated from Streptomyces sources in subsequent years. The abundance of natural, active tetracyclines, coupled with extensive synthetic alterations, provides a rich collection of compounds from which to build meaningful structure-activity relationships. As was found for the aminoglycosides, previous observations of tetracycline structure and activity can be rationalized from recent tetracycline/30S crystal structures (11,12). 

Tetracyclines are the first broad-spectrum antibiotic that was used to halt the growth of many gram-positive and gram-negative bacteria. It is used to treat a variety of infections including acne vulgaris, actinomycosis, anthrax, bronchitis, and other systemic bacterial infections including bacterial urinary tract infections. 

The selectivity of the tetracyclines, so much used in treating bacterial infections in mammals, depends on a similarly favourable distribution the bacteria concentrate these antibiotics whereas mammalian cells do not. Concentration of tetracyclines by bacteria (both Gram-positive and -negative types) was found to be a function of the cytoplasmic membrane (Franklin, 1971). Because of this difference, tetracyclines inhibit ribosomal protein synthesis in bacteria at doses which do not affect it in higher organisms (Franklin, 1963b, 1966). This selectivity depends on the intactness of the mammalian cell membrane, because isolated ribosomes (rat liver was used) were found to be as subject to inhibition of protein synthesis as bacterial ones were (Franklin, 1963a Section 11.8). 

Tetracycline 11.36) and its derivatives are octahydro-naphthacenes. The tetracyclines are among the most used of all drugs in treating systemic bacterial infections. They cannot act like oxine because their action on bacteria is slow and is not promoted by iron (Albert and Rees, 1956). They have very little action on fungi. [See Section 4.1 (p. 144) for background material on tetracyclines.]... 

Veterinary drugs are used to treat animals for bacterial infections (antibiotics) and parasitic infestations (anthelmintics, coccidiostats), to enhance growth (antibiotics, anabohcs, partitioning agents, thyrostats), to control fertility and reproduction (steroid hormones), or to alter behavior (tranquillizers and sedatives). Within each of the drug types there are different classes and methods for residue analysis are typically class specific (e.g., methods for the class of tetracycline antibiotics). In certain cases, mrdtiresidue methods are available that are broader than specific classes. 

Viral infections—from influenza and the common cold to the more serious herpes infections and AIDS (acquired immune deficiency syndrome)—account for about 60% of illnesses, contrasted with about 1 5% for bacterial infections. Since the 1 940s, chemists have developed all sorts of highly effective antibiotics (sulfa drugs, penicillins, tetracyclines, and others) that are effective against bacterial infections, but progress with antiviral agents has been slower and more difficult. Why is this so, and what hope do we have for combating viral infections ... 

In humans, contact with LPS may occur not only during a bacterial infection but also via LPS-contaminated medicaments and solutions administrated intravenously (parenteralia). Since the biological effects of LPS may appear even at concentrations of 1 ng per 1 kg of body weight, drugs intended for parenteral use, have to be endotoxin-free , i.e., thoroughly depyrogenated. In fact parenteralia have to comply with LPS threshold limits (in EU , endotoxin unit) regulated by pharmacopoeias. For example, tetracycline hydrochloride may not contain more than 0.5 ELf/mg. Similar limits exist for insulin (0.8 EU/insulin unit), hyaluronidase (2.3 EU/ hyaluronidase unit), the sodium salt ofheparin for injection (0.003 EU/heparin unit). ... 

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