Nosocomial pneumonia antimicrobial therapy

Timsit JF, Misset B, Renaud B, Goldstein FW, Carlet J. Effect of previous antimicrobial therapy on the accuracy of the main procedures used to diagnose nosocomial pneumonia in patients who are using ventilation. Chest 1995 108 1036-1040. 

Once the diagnosis of nosocomial pneumonia has been established, several important factors must be considered before a rational empirical antimicrobial regimen can be chosen. These include severity of illness and comorbid conditions of the patient, prior antibiotic use, early versus late onset of infection, results of the sputum Gram s stain, and the resident flora profile of the institution, particularly in the intensive care unit (Table 1). Empirical antimicrobial therapy for nosocomial pneumonia in a ventilated patient with renal failure in whom multiple intra-abdominal abscesses develop following colon resection is very different from the patient who aspirates following an otherwise uncomplicated cholecystectomy. 

The ability to detect ESBLs has clinical relevance because it will have an impact on antibiotic therapy. Producers of ESBLs are suspected when susceptibility testing indicates resistance to ceftazidime (but may be paradoxically susceptible to ceftriaxone and cefotaxime by the minimal inhibitory concentration [MIC] or disc diffusion) and susceptible to the cephamycins (11). More recently, a breakpoint of 2 ig/mL to cefpodoxime has been suggested as a standard. Another method of detection is the use of the E-test strip with a gradient of ceftazidime on one side and ceftazidime in combination with clavu-lanate on the other. The ESBLs are thought to be present when enhancement of inhibition is demonstrated. Table 2 highlights some of the more common resistance mechanisms for antimicrobial agents used commonly in the treatment of nosocomial pneumonia. 

Similar to cases with P. aeruginosa, nosocomial ventilator-associated pneumonia caused by Acinetobacter is associated with a high mortality rate. In a study of 48 patients (70), pneumonia caused by these two organisms have a mortality rate of 71.4% compared to other pathogens (40.7%), with the observation that this rate was in excess of that observed for the underlying disease however, the impact of antimicrobial therapy was not discussed. 

The optimal duration of antimicrobial therapy of nosocomial pneumonia is not well established. Generally, a course for 10 to 21 days is recommended, the longer course would be reasonably indicated for those patients with extensive infection involving multiple lobes, highly resistant organisms such as Acineto-bacter and P. aeruginosa, cavitary disease, or malnutrition (16,45). Because the bioavailability of the quinolones when administered orally is equivalent... 

Table 7 Selected Antimicrobial Agents in the Therapy of Bacterial Pathogens of Nosocomial Pneumonia with Acquisition Costs ...

Table 5 Antimicrobial Therapy for Nosocomial Bacterial Pneumonia and Tracheitis in Children... 

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