The cephalosporins are semisynthetic antibiotics derived from products of various microorganisms, including Cephalosporium and Streptomyces. All cephalosporins have a 7-aminocephalosporanic acid composed of a di-hydrothiazine ring fused to a p-lactam ring (Fig. 45.3).As with the penicillins, the cephalosporin p-lactam ring is the chemical group associated with antibacterial activity. The different pharmacological, pharmacokinetic, and antibacterial properties of individual cephalosporins result from substitution of various groups on the basic molecule. Cephalosporins also vary in acid stability and p-lactamase susceptibility. Table 45.2 shows the large number of available cephalosporins.

The p-lactamases (penicillinases) inactivate some cephalosporins but are much less efficient than are the cephalosporinases (p-lactamases specific for the cephalosporins). Resistance to cephalosporins also results from modification of microbial PBPs.

Constipation Prescription

Constipation Prescription

Did you ever think feeling angry and irritable could be a symptom of constipation? A horrible fullness and pressing sharp pains against the bladders can’t help but affect your mood. Sometimes you just want everyone to leave you alone and sleep to escape the pain. It is virtually impossible to be constipated and keep a sunny disposition. Follow the steps in this guide to alleviate constipation and lead a happier healthy life.

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