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 Monobactams  Monobactams are a group of beta lactam antibiotics since it has the same beta lactam ring like that in penicillin and cephalosporins. However, it has only one ring and lacks a second ring like thiazolidine or dihydothiazine. Aztreonam is the most common monobactam antibiotics used in clinical practice which was introduced in 1984 A.D. Chemical structure similar to Ceftazidime. Mechanism of action Similar to other beta lactam antibiotics by prevention of transpeptidation reaction. Spectrum of activity Gram negative coverage similar to 3 rd generation cephalosporins. Good in vitro activity against the majority of gram-negative aerobic and facultative bacteria, including the Enterobacteriaceae and  P. aeruginosa. It has virtually no activity against gram-positive organisms or anaerobes; the majority of  strains of  Acinetobacter  and  S. maltophilia  are resistant and resistant strains of  P.aeruginosa  frequently emerge du...

  For PDF  Cephalosporins Introduction: The word antibiotics come from the word - antibiosis which means against life. Cephalosporins are one of the most commonly used antibiotics in clinical practice. It was first discovered formed from " Cephalosporium acremonium " from a sewage outfall in  Sardinia in 1948 by an Italian scientist "Giuseppe Brotzu".     Many different types of cephalosporins have been developed since its first identification. Structure of Cephalosporins. In cephalosporins, the β-lactam ring is bonded to a six-membered dihydrothiazine ring, or cepham. First generation cephalosporins were created by modifying the R1 site of the cephalosporin structure. The succeeding generations of cephalosporins have been synthetically produced with modifications at the R1 and R2 sites. These changes in the R site also differentiate the spectrum of activity amongst the cephalosporins. Mechanism of action of Cephalosporins Since the cephalosporin a...