Bacterial control antibiotics

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. 

Also see BACTERIA IN FOOD, section headed "Bacterial Control Methods" and ANTIBIOTICS, section headed "Antibiotics in Foods.")... 

Prior to the 1980s, bacterially produced antibiotics were the mainstay of control of pathogenic organisms in humans (P-lactams, chloramphenicol, tetracyclines, erythromycin, streptomycin, gentamicin, rifamycin, vancomycin, lincomycin), in foods (nisin), in animals (monensin) and in plants (polyoxins). However, new antibiotics were clearly needed because of (1) the development of resistance in pathogens (2) the evolution of new... 

Resistance to antimicrobial agents is of concern as it is well known that bacterial resistance to antibiotics can develop. Many bacteria already derive some nonspecific resistance to biocides through morphological features such as thek cell wall. Bacterial populations present as part of a biofilm have achieved additional resistance owkig to the more complex and thicker nature of the biofilm. A system contaminated with a biofilm population can requke several orders of magnitude more chlorine to achieve control than unassociated bacteria of the same species. A second type of resistance is attributed to chemical deactivation of the biocide. This deactivation resistance to the strong oxidising biocides probably will not occur (27). 

P-Lactams. AH 3-lactams are chemically characterized by having a 3-lactam ring. Substmcture groups are the penicillins, cephalosporias, carbapenems, monobactams, nocardicias, and clavulanic acid. Commercially this family is the most important group of antibiotics used to control bacterial infections. The 3-lactams act by inhibition of bacterial cell wall biosynthesis. 

Members of the aminoglycoside class of antibacterial antibiotics retain an important role in the control of bacterial infectious disease, especially in... 

The University of Idaho and USFWS, with funds from the Bonneville Power Administration, are also gathering data for registration of erythromycin. Erythromycin is intended for control of bacterial kidney disease in salmonid fingerlings that can also be transmitted by broodstock to the eggs (9). If research is completed on schedule and data indicate that the compound is safe and effective, registration is scheduled for 1994 (see Antibiotics, MACROLIDES). 

All feed streams are sterilised before being metered into the fermentation vessel. Contaminants resistant to the antibiotic rarely find their way into the fermenter. When they find a way to contaminate media, their effects are so catastrophic that prevention is of paramount importance. A resistant, (3-lactamase producing, fast-growing bacterial contaminant can destroy the penicillin.5 The contaminants not only consume nutrients intended for the fungus, but also cause loss of pH control and interference with the subsequent extraction process. 

Before therapy is begun, culture and sensitivity tests (see Chap. 7) are performed to determine which antibiotic will best control the infection. These drug are of no value in the treatment of infections caused by a virus or fungus. There may be times when a secondary bacterial infection has occurred or potentially will occur when the patient has a fungal or viral infection. The primary health care provider may then order one of die... 

When a UTI has been diagnosed, sensitivity tests are performed to determine bacterial sensitivity to the drugp (antibiotics and urinary anti-infectives) that will control the infection. The nurse questions the patient regarding symptoms of the infection before instituting therapy. The nurse records the color and appearance of the urine. The nurse takes and records die vital signs. A urine sample for culture and sensitivity is obtained before the first dose of the drug is given. 

Although antibiotics have rendered possible the medical control of various infectious agents (mainly bacterial), numerous pathogens remain for which no effective treatment exists. Most of these pathogens are non-bacterial (e.g. viral, fungal and parasitic, including protozoal). In addition, the overuse/abuse of antibiotics has hastened the development of antibiotic-resistant super bacteria , which have become a serious medical problem. 

Abstract Resistance to modern antibiotics is currently a major health concern in treating infectious diseases. Abuse, overuse, and misuse of antibiotics in treating human illness have caused the pathogens to develop resistance through a process known as natural selection. The most common mechanism of resistance to -lactam antibiotics is the production of /3-lactamases, which destroy -lactam antibiotics before they reach the bacterial target. Over the last two decades, combination therapy involving treatment with a -lactam antibiotic and a /3-lactamase inhibitor has become very successful in controlling -lactamase-mediated bacterial resistance. Currently available inhibitors like... 

There is no proven treatment for smallpox, but in persons exposed to smallpox who do not show symptoms as yet, the vaccine — if given within four days after exposure — can lessen the severity of or even prevent illness. However, once a patient shows symptom, treatment is limited to supportive therapy and antibiotics to treat bacterial infections. Patients with smallpox can benefit from supportive therapy such as intravenous fluids, and medicines to control fever or pain. 

Bacterial resistance to conventional antibiotics has become a serious problem in infection control, and has led to intensive research efforts to develop an effective novel antimicrobial agent. Antimicrobial peptides have already played a crucial role in pharmaceutical research as biomedically useful agents or as lead compounds for drug development. More specifically, cyclic peptides have shown some potential as a possible new class of... 

The lipid bilayer forms a barrier to transport of matter into and out of the cell. This barrier function is essential since cells need to be able to control their internal milieu, regardless of the external environment. (Some antibiotics work by disrnpting the barrier function of bacterial membranes see Chapter 23). At the same time, some communication of signals and materials across the bilayer must occur. Special mechanisms to do this are a key property of biological membranes. More specifically, these mechanisms are the province of proteins that one finds in these membranes. 

Enzyme inhibitors are chemicals that may serve as a natural means of controlling metabolic activity by reducing the number of enzyme molecules available for catalysis. In many cases, natural or synthetic inhibitors have allowed us to unravel the pathways and mechanisms of intermediary metabolism. Enzyme inhibitors may also be used as pesticides or drugs. Such materials are designed so that they inhibit a specific enzyme that is peculiar to an organism or a disease state. For example, a good antibiotic may inhibit a bacterial enzyme, but it should have no effect on the host person or animal. 

Numerous cases of the use of antibiotics(especially cycloheximide, ohyamycin, streptomycin, tetracyclines, penicillin, griseofulvin, and polymyxin) against several bacterial and fungal diseases are now known(33-35). In the United States of America, Merck sells preparations of streptomycin and Upjohn sells that of cycloheximide for the control of the diseases of ornamental plants(R.Burg,... 

---