Streptococcus pneumoniae (SP) is the most common pathogen associated with respiratory tract infections and community acquired pneumonia (CAP) and it is associated with a high mortality and morbidity linked to significant health care costs. Over the last 20 years or so the emergence of multidrug-resistant (MDR) strains of SP have become a global problem and better treatments are urgently needed.  Treatment with a single antibiotic, such as a beta-lactam or third-generation cephalosporin, used to be regarded as effective but the emergence of MDR-resistant strains of S. pneumoniae has led physicians to question this as empirical therapy. Recent evidence suggests that dual therapy is more effective than monotherapy, especially in patients with severe CAP. Consequently, this study was carried out by investigators in the Department of Physiology, Immunology Laboratory, University of Calcutta, University Colleges of Science and Technology, Calcutta, India. Clinical isolates of S. pneumoniae were obtained from a patient admitted to hospital in Calcutta with severe pneumonia and the in vitro susceptibility to 19 antibiotics, alone or in combinations, was tested using a variety of methods including measurement of the minimum inhibitory concentrations, minimum bactericidal concentrations, checkerboard assay and time kill curves. The hemolytic activity was increased significantly with combination therapy and, interestingly, the combination of levofloxacin and ceftriaxone was able to kill cells much more quickly than any of the other combinations used. Also, the investigators found that newer generation cephalosporins were not as effective as earlier generations when used in combination with levofloxacin against MDR S. pneumoniae isolates.

PMID: 26230119

J Infect Dev Ctries. 2015 Jul 30;9(7):702-709. doi: 10.3855/jidc.4711.

Source : http://www.ncbi.nlm.nih.gov/pubmed/26230119?dopt=Abstract