Usefulness of gram-stained sputum obtained just after administration of antimicrobial agents as the earliest therapeutic indicator for evaluating the effectiveness of empiric therapy in community-acquired pneumonia caused by pneumococcus or Moraxella catarrhalis

Abstract

We present here three cases in which morphological changes and/or a decreased number of Streptococcus pneumoniae or Moraxella catarrhalis could be observed in gram-stained sputum obtained just after the first administration of an antimicrobial agent. Case 1 was a 53-year-old man with pneumonia caused by gram-positive diplococcus, identified as S. pneumoniae, who was administered 2g of ampicillin over a period of 1h. Gram-stained sputum showed smaller or gram-negative pneumococci at the completion of administration of the agent, a decreased number of cocci at 1h after administration, and almost no cocci at 12h after the completion of administration. Case 2 was a 72-year-old woman with pneumonia caused by diplococcus, identified as S. pneumoniae, who was administered 2g of ampicillin over a period of 1h. Gram-stained sputum showed weakly stained, small cocci at the completion of administration of the agent and few cocci at 1h after the completion of administration. Case 3 was a 58-year-old woman with pneumonia caused by a gram-negative diplococcus, identified as Moraxella catarrhalis, who was administered 1g of cefotaxime over a period of 30min. Gram-stained sputum showed few extracellular cocci and some intracellular cocci inside neutrophils 1h after administration and no cocci 2h after the completion of administration. These three cases showed that gram-stained sputum obtained just after and/or 1h after administration of the first antimicrobial agent were suitable as the quickest therapeutic indicator of the effectiveness of empiric therapy, with the effectiveness of the agent being shown much earlier than with markers such as the white blood cell count and C-reactive protein level.