Bacteria, Gram positive

FIGURE 100 Vancomycin, a bactericidal antibiotic, inhibits cell-wall synthesis in Gram-positive bacteria. It is effective against methicillin-resistant organisms and as an alternate to semisynthetic penicillins or cephalosporins in patients with severe staphylococcal infections. 

Vancomycin has caused reversible neutropenia, nephrotoxicity, hypotension (rapid bolus injection), and pseudomembranous colitis (rare). The concomitant use of vancomycin with aminoglycosides increases the risk of 

Vardenafil hydrochloride is a phosphodiesterase type 5 inhibitor. It enhances the effect of nitric oxide at the nerve ending and endothelial cells in the corpus cavemosum by inhibiting phosphodiesterase type 5 in the corpus cavemosum of the penis. This results in vasodilation, increased inflow of blood into the corpora cavernosa, and ensuing penile erection upon sexual stimulation. It is used to treat erectile dysfunction. 

This immune substance is used for passive immunization of susceptible patients, primarily patients who are immunocompromised owing to exposure to varicella (chicken pox or herpes zoster). 

The vasodilators may be classified as ventodilators, arterial dilators, or balanced-type vasodilators (Table 26). 

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Tolypomycin Y (48) shows strong antibacterial activity against gram-positive bacteria and Neisseriagonorrheae. When adininistered by subcutaneous, intraperitoneal, and intravenous routes, tolypomycin Y is effective in mice infected with Staphylococcus aureus Streptococcuspyrogenes and Diplococcuspneumoniae. Cross-resistance is observed with rifampicia but not with other antibiotics. Resistance to tolypomycin Y develops rapidly. The bioactivity of tolypomycin R... 

Kanglemycin. Kanglemycia (74) (Fig. 8) is isolated from the fermentation broth filtrate of Nocardia mediterranei var kanglensis (1747-64) and its stmcture determiaed by x-ray crystallographic studies. The antibiotic is active against gram-positive bacteria (28). 

Qindamycin, 7(5)-7-chloro-7-deoxyliQcomycin [18323-44-9] (1, R = H, R = Q), also known as Cleocin, first resulted from the reaction of lincomycin and thionyl chloride (54) improved synthetic methods involve the reaction of lincomycin and triphenylphosphine dichloride or triphenylphosphine in carbon tetrachloride (55). Clindamycin is significantly more active than lincomycin against gram-positive bacteria in vitro, and is absorbed rapidly following oral adnainistration. Clindamycin 2-palmitate [36688-78-5], (6, R = R = OC(CH2) 4CH2), 2-palmitate ester of clindamycin, is... 

Oxeta.nocins, Oxetanocia A (49), formerly oxetanocia, is the first naturally occurring oxetanose derivative and is isolated from Bacillus megaterium (1,145). It inhibits gram-positive bacteria, herpes vimses, and human immunodeficiency vims (HIV) (146). The chemical synthesis of (49) and several derivatives has been reported (147). 

Neosidomycin (63) and SF-2140 (64) are indole N-glycosides produced by S. hjgroscopicus A.ctinomadura respectively (195,196). A revised stmcture for (63) has appeared (197). Compound (64) contains an a-N-glycoside linkage. Both (63) and (64) show activity against gram-positive bacteria, yeast, fungi, and vimses. 

Activity against gram-positive bacteria = P gram-negative bacteria = N mycobacteria = M fungi = F tumors = T and viruses = V. Only peptides not discussed in the text of this article are given references. 

Bacitracin. Bacitracin, a cycHc peptide active against gram-positive bacteria, was discovered in 1943. Bacitracin received dmg certification in 1949 (60—62). Whereas human usage of bacitracin is almost exclusively topical, the vast majority of bacitracin manufactured worldwide is used as an animal feed additive. Reviews of work on bacitracin include its chemistry (63—67), comprehensive aspects (62), medical aspects (62,68), biosynthesis on large enzyme complexes and genetics (69—71), and production (71,72). 

Nisin acts bactericidally primarily against gram-positive bacteria. It acts best at acid pH and is almost insoluble at physiological pH. Nisin and probably all lantibiotics appear to permeabilize the bacterial ceU membrane to release small molecules, resulting in an immediate coUapse of the membrane... 

Three more antibiotics, all discovered about 1953, are also derivatives of cytosine. Amicetin, bamicetin and plicacetin may all be isolated from Streptomyces plicatus and all have some activity against some acid-fast and Gram-positive bacteria as well as some other microbial systems (69MI21301). Structural work in this area is fascinating (62JOC2991). 

Lipoteichoic acids (from gram-positive bacteria) [56411-57-5J. Extracted by hot phenol/water from disrupted cells. Nucleic acids that were also extracted were removed by treatment with nucleases. Nucleic resistant acids, proteins, polysaccharides and teichoic acids were separated from lipoteichoic acids by anion-exchange chromatography on DEAE-Sephacel or by hydrophobic interaction on octyl-Sepharose [Fischer et al. Ear J Biochem 133 523 1983]. 

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