Chapter 128. Pneumococcal Infections (Part 9) potx

Duration of Therapy The optimal duration of treatment for pneumococcal pneumonia is uncertain.. Early in the antibiotic era, most physicians treated pneumococcal pneumonia for 5–7 days.

Chapter 128 Pneumococcal Infections

(Part 9)

Inpatient Therapy

Pneumococcal pneumonia is readily treatable with β-lactam antibiotics The

conventional dosages shown in Table 128-5 are acceptable against intermediately

resistant strains and against many or most fully resistant isolates Recommended

agents include ceftriaxone and cefotaxime Ampicillin is also widely used, usually

in the form of ampicillin/sulbactam The likely efficacy of newer quinolones such

as moxifloxacin, macrolides such as azithromycin, and clindamycin is discussed

above On the basis of in vitro considerations, vancomycin is likely to be

uniformly effective against pneumococci; this drug or a quinolone should be used

together with a third-generation cephalosporin for initial therapy in a patient who

is likely to be infected with a highly antibiotic-resistant strain Patients who have

had a severe allergic reaction to penicillins or cephalosporins may be treated with

a carbapenem (e.g., imipenem-cilastatin), a quinolone, or vancomycin The failure

of a patient to respond promptly should at least prompt consideration of drug

resistance Evidence for loculated infections (such as empyema) and/or other

causes of fever should be sought and addressed appropriately

Duration of Therapy

The optimal duration of treatment for pneumococcal pneumonia is

uncertain Pneumococci begin to disappear from the sputum within several hours

after the first dose of an effective antibiotic, and a single dose of procaine

penicillin, which produces an effective antimicrobial level for 24 h, was curative

in otherwise-healthy young adults in an era when all isolates were susceptible

Early in the antibiotic era, most physicians treated pneumococcal pneumonia for

5–7 days In the absence of data suggesting a need for longer treatment, younger

physicians tend to treat the infection for 10–14 days In the opinion of this author,

a few days of close observation and parenteral therapy followed by an oral

antibiotic—with the entire course of treatment continuing for no more than 5 days

after the patient becomes afebrile—may be the best approach for treating

pneumococcal pneumonia, even in the presence of bacteremia Cases with a

second focus of infection (e.g., empyema or septic arthritis) require longer

therapy

Meningitis

(Table 128-6) Pneumococcal meningitis should be treated initially with

ceftriaxone plus vancomycin Equivalent doses of cefotaxime or cefepime may be

used in place of ceftriaxone The cephalosporin will be effective against most—

but not all—isolates and will readily penetrate the blood-brain barrier; all isolates

will be susceptible to vancomycin, but this drug has a somewhat unpredictable

capacity to cross the blood-brain barrier If the isolate is shown to be susceptible

or intermediately resistant, treatment can be continued with ceftriaxone, and

vancomycin can be discontinued If the organism is resistant, treatment with both

drugs should be continued A very few studies of experimental animals suggest

benefits of the addition of rifampin, but in vitro studies indicate antagonism

between this drug and ceftriaxone or vancomycin; in the absence of data to

support the practice in humans, this author does not recommend that rifampin be

added Imipenem may be used in place of the cephalosporin in patients who have

had life-threatening allergic reactions to β-lactam antibiotics The total duration of

therapy for pneumococcal meningitis is 10 days A recent study demonstrated

clear benefit from the addition of glucocorticoids (Chap 376)

Table 128-6 Treatment of Pneumococcal Meningitis

Circumstance Appropriate Coursea

Diagnosis of

pneumococcal meningitis;

Treat with ceftriaxone, 2 g q12h, plus

vancomycin, 500 mg q6h, until antibiotic

antibiotic susceptibility unknown susceptibility of organism is known

Susceptibility results

available

Continue treatment with ceftriaxone

alone if organism is susceptible or intermediate;

continue both ceftriaxone and vancomycin if

organism is resistant

Life-threatening penicillin

allergy

Treat with imipenem, 500 mg q6h, rather

than a β-lactam antibiotic

a

Treatment should be administered for 5–7 days after defervescence or for a

total of 10 days

Endocarditis

Pneumococcal endocarditis is associated with rapid destruction of heart

valves Pending results of susceptibility studies, treatment should be initiated with

ceftriaxone or cefotaxime; if the prevalence of highly resistant strains increases, it

might be prudent to add vancomycin until results of susceptibility studies are

available In vitro, aminoglycosides are somewhat synergistic and rifampin or

quinolones are antagonistic with β-lactams against pneumococci; there is no clear

evidence from in vivo studies that adding any of these antibiotics to the regimen is

beneficial

Other Therapeutic Modalities

Addition of drotrecogin, an activated protein C preparation, may be

beneficial in treating patients with severe pneumococcal sepsis Glucocorticoids

and agents that block the action of TNF-α, IL-1, or platelet-activating factor have

conferred no benefit