Antimicrobial delayed therapy

It is difficult to identify who wiU benefit from antimicrobial therapy. With or without treatment, about 60% of children who have acute otitis media are symptom-free within 24 hours. In almost 40% of the remaining children, antibiotic use reduces the duration of symptoms by about 1 day. A trial of 315 children (6 months to 10 years of age) compared immediate antibiotic treatment with a 72-hour delay in treatment that was to be given only if the child had not improved. Symptoms continued for 1 extra day in 10% to 20% of the delayed-therapy group, but 10% fewer also experienced diarrhea. At 3 days, there was no difference in symptoms. In the delayed-therapy group, only 24% of children evenmally received antibiotics, and 77% of parents reported being satisfied with this approach. ... 

Ideally, lumbar puncture to obtain cerebrospinal fluid (CSF) for direct examination and laboratory analysis, as well as blood cultures and other relevant cultures, should be obtained before initiation of antimicrobial therapy. However, initiation of antimicrobial therapy should not be delayed if a pretreatment lumbar puncture cannot be performed. 

Determine if the patient can undergo an immediate LP or if the LP should be delayed until a CNS mass lesion can be ruled out. If the LP is delayed, blood cultures should be drawn and appropriate empirical antimicrobial therapy initiated immediately. 

Infected body materials must be sampled, if at all possible or practical, before the institution of antimicrobial therapy, for two reasons. First, a Gram stain of the material may reveal bacteria, or an acid-fast stain may detect mycobacteria or actinomycetes. Second, a delay in obtaining infected fluids or tissues until after therapy is started may result in falsenegative culture results or alterations in the cellular and chemical composition of infected fluids. 

Early initiation of antimicrobial therapy results in faster resolution of signs and symptoms. Delays AT in therapy (if awaiting cultures) can be made safely for up to 9 days after symptom onset and still prevent major complications such as rheumatic fever. 

Ideally, the antimicrobial agent used to treat an infection is selected after the organism has been identified and its drug sensitivity established. However, in the critically ill patient, such a delay could prove fatal and immediate empiric therapy is indicated. 

Initial selection of antimicrobial therapy is nearly always empirical, which is the initiation of antimicrobials sometimes prior to documentation of the presence of infection and before the offending organism is identified. Infectious diseases generally are acute, and a delay in antimicrobial therapy may result in serious morbidity or even mortality. An example is the rapidly lethal nature of various forms of meningitis. Thus empirical antimicrobial therapy selection is... 

Recommended empirical therapy differs among outpatients, hospitalized patients, and hospitalized patients admitted to an intensive care unit (Table 106-12). Additionally, antimicrobial therapy should be initiated in hospitalized patients with acute pneumonia within 8 hours of admission because an increase in mortality has been demonstrated when therapy was delayed beyond 8 hours of admission. 

Delayed treatment decreases antibiotic use by 31% (and associated side effects) and minimizes bacterial resistance to rates as low as 30% to 50% of that in countries that do not delay antimicrobial therapy. Some clinicians feel that delayed treatment is not... 

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