Tetracyclines, history

The conventional bioassays based on methodology developed by FDA and expanded by FSIS use four extractant buffers, five test organisms, five growth media, two incubation temperatures, and penicillinase to detect, identify, and/or quantify antibiotics such as the penicillins, streptomycins, tetracyclines, neomycins, erythromycin, tylosin, etc. Bioassay laboratory results are used by FSIS to take regulatory action and by FDA to prosecute farmers with histories of improperly withdrawing antibiotics before marketing their herds or flocks. 

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. 

Lyme disease, caused by the spirochete Borrelia burgdorferi, incites a variety of ocular manifestations, the most common being a conjunctivitis that occurs in up to 10% of patients with early disease. Although the characteristics of the conjunctivitis have not been clearly defined, several reports have described fitlhcular conjunctivitis. Increased antibody titers to B. burgdorferi indicate the presence of Lyme disease. A history of tick bite or erythema chronicum migrans should alert the clinician to consider Lyme disease in the differential diagnosis in areas of the country where this disease is prevalent. Treatment of Lyme disease conjunctivitis should include topical tetracycline as an adjunct to oral doxycycline, 100 mg twice daily for 2 to 3 weeks, which is used to treat the systemic infection. 

Fixed drug eruptions have been analysed in 450 patients (130). The ratio of men to women was 10 11. The mean age of the men was 30 years, and that of the women 31 years. In 13% the fixed drug eruption had occurred for the first time, 2.7% had had more than 40 episodes. There was atopy in 11%, and 23% had a positive family history of drug reactions. Co-trimoxazole was the most common cause of fixed drug eruptions. Other antibiotics included tetracycline, metronidazole, amoxicillin, ampicillin, erythromycin, and clindamycin. 

The successes achieved in the past decade with chemically modified penicillins, tetracyclines, and lincomycin, undoubtedly influenced the judgment of the panel that preparation of structural analogs of useful antibiotics by chemical or other means should be ranked as one of the two most promising discovery approaches for the next decade. Before proceeding further with the evaluation made by the respondents of the five approaches (Table VII), some aspects of the history and nature of the structural modification approach are examined. 

Penicillinase-resistant peiticilUns should be administered cautiously to persons with a history of sensitivity to any penicillins. Tetracycline, a bacteriostatic antibiotic, may antagonize the bactericidal effects of peitidlUn (see also Table 23). 

Agneu ( neu ) Moania complains to his physician of a fever and cough. His cough produces thick yellow-brown sputum. A stain of his sputum shows many Gram-positive, bullet-shaped diplococci. A sputum culture confirms that he has pneumonia, a respiratory infection caused by Streptococcus pneumoniae, which is sensitive to penicillin, erythromycin, tetracycline, and other antibiotics. Because of a history of penicillin allergy, he is started on oral erythromycin therapy. 

A 24-year-old woman has primary syphilis. She has a history of penicillin hypersensitivity, so tetracycline will be used to treat the infection. Which one of the following statements about the proposed drug treatment of this patient is false ... 

Your 23-year-old female patient is pregnant and has gonorrhea. The past medical history includes anaphylaxis following exposure to amoxicillin. Worried about compliance, you would like to treat this patient with a single dose, so you choose (A) Cefixime Ceftriaxone Ciprofloxacin Spectinomycin Tetracycline... 

Spectinomycin (2 g intramuscularly) is the appropriate choice in this case. Avoid cephalosporins in patients with a history of severe hypersensitivity to penicillins, and avoid fluoroquinolones (see Chapter 46) in pregnancy. Tetracyclines have been used in the past for gonorrhea but not as single doses, and they too should be avoided in pregnancy. The answer is (D). 

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