Antibacterial activity agains

On the basis of log bacterial survival rates, the antibacterial activity of rifaximin was greater than that of paromomycin against Enterococcus spp., anaerobic cocci, Bac-terioides spp. and Clostridium spp. isolated in fecal samples from 20 patients with subclinical hepatic encephalopathy (fig. 4) [81]. On the other hand, E. coli dead Klebsiella spp. appeared more susceptible to paromomycin while both antibiotics showed equal potency against Proteus spp. [81]. Here again it should be pointed out that stool concentrations of rifaximin are 250-500 times higher than the MIC90 values [71], which makes the in vitro differences of activity between this and other antimicrobials meaningless from a clinical standpoint. 

Phenazopyricline hydrochloride was formerly used as a urinary antiseptic. Although it isactivc in vitro again.st staph-yliK occi. streptococci, gonococci, and . coli. it has no useful antibacterial activity in the urine. Thus, its present utility lies in its local analgesic effect on the mucosa of the urinary tract. 

The diethyltin and also the dimethyltin products were studied because of their outstanding antibacterial activities. Both showed good inhibition of the Balb/3T3 cells at about a polymer concentration of 10 pg/mL. Again, the polymers showed mild activity against the HTB 75 cancer cell line. Greater than 50% inhibition was found for the diethyltin polymer at 30 pg/mL. 

XIV and XVI were tested against both gram positive and gram negative bacteria as were products XIII and XV which were prepared from XIII and XV which had been subjected to reaction conditions identical to those employed to prepare XIV and XVI with no VI being present in the reaction mixtures. The antibacterial test results shown in Table 6, again may indicate a preferential antibacterial activity of polythiosemicarbazides for gram positive bacteria. 

It is important to note that many non-sulfonamides are known that can compete with j AB (/ -aminobenzoic acid). The most used of these is dapsone 9.17), 4,4 -di(aminophenyl)sulfone, the sheet anchor of all leprosy therapy. Others contain no sulfur atom, but have the requisite steric and electronic resemblance to pAR. For example, the insertion of a chlorine atom into either the 2- or the 3-position of pAR makes an active anti-pAB substance (Wyss, Rubin and Strandskov, 1943). Diaminobenzil 2.15) is several times more active against bacteria than sulfanilamide, and is reversed by / AB (Kuhn, Weygand and Moller, 1943). Again,/ -aminobenzenearsonic acid, atoxyl 6.2) has a typical sulfanilamide-like action (Albert, Falk and Rubbo, 1944). Although, in general, arsonic acids are not antibacterial, atoxyl forms an exception because it resembles pAR sufficiently, sterically and electronically, to compete with it. 

The distribution of free SO2 in solution is a pH-dependent equilibrium (see Fig. 1.8). Again, it is the molecular form that is antimicrobial. Bisulfite may have limited antibacterial properties and 803 has no activity in this regard. Upon addition, free SO2 combines with susceptible substrates, such as acetaldehyde, pigments, sugars, and o-acids, yielding more benign... 

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