CEPHALOSPORINS

This is potentially a crazy confusing topic.

The basic principles are that the 1st generation ones, derived from fungus, are good for most G+ bugs, including ones that make Beta-lactamase (i.e. = staphs!), but are useless against most G- bugs, with the important exception of E. koli and Klebsiella.
The only aerobic G+ they won't kill are MRSA, Listeria and Enterococcus.

So, they can be used for any aerobic G+ infection and for most UTI's.

Examples are cephalothin, cephalexin, cefazolin.

The second generation ones can be broken down into:-
* " 1st generation spectrum cephalosporins with activity against H.inf" such as cefuroxime, cefaclor.
* "1st generation spectrum cephalosporins with a bit of anaerobic activity" such as cefoxitin.

The second generation are not true cephalosporins. They are cephamycins.

The third generation cephalosporins are called "broad spectrum cephalosporins".
They have sacrificed anti-staphylococcal and anaerobic activity for G-activity.
The only G-'s that they won't kill are the ESBL's (i.e. those bugs with extended spectrum beta-lactamases, e.g. Enterobacter) and Pseudomonas.
The only G+'s that they will kill with certainty is Streptococci (except for enterococci).
They are ceftriaxone, cefotaxime.

There is also a subfamily of third generationers that are "third generation cephs with anti-pseudomonal activity". They are ceftazidime, cefipime.