Clarithromycin. All carbapenems are members of the beta lactam class of antibiotics and Clarithromycin is not. Carbapenems are used in the treatment of infections suspected to be caused by multidrug-resistant bacteria. Clarithromycin is one of the macrolide antibiotics. It works in stopping the growth of bacteria by acting as a protein synthesis inhibitor. Clarithromycin is also used in combination with other antibiotics, in the treatment of multidrug-resistant bacteria.