Staphylococcal Pneumonia - Download as DOC by benbenzhou


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									Pneumonia Caused By Haemophilus influenzae
H. influenzae, named because it was erroneously implicated as a cause of
influenza during the pandemic of 1889, is a relatively common cause of
bacterial pneumonia, second only to Streptococcus pneumoniae in most
studies of community-acquired lung infections. Strains containing the
type b (Hib) polysaccharide capsule are most virulent and most likely to
cause serious disease, including meningitis, epiglottitis, and
bacteremic pneumonia. These infections have nearly disappeared in the USA
and other developed countries because of use of Hib vaccine. Strains of
H. influenzae that commonly colonize the upper airways of adults are
usually nonencapsulated (not type b). These strains may colonize the lower
respiratory tract of patients with chronic bronchitis and are often
implicated in exacerbations of chronic bronchitis.

Symptoms, Signs, and Diagnosis

Hib pneumonia usually occurs in children (median age: 1 yr). Coryza
precedes most cases, and early pleural effusions occur in about 50%.
Bacteremia and empyema are not common. Most adults have infections
involving nonencapsulated strains with a bronchopneumonia that resembles
other bacterial pneumonias.

Gram stain of expectorated sputum shows numerous, small, gram-negative
coccobacilli; the organism is relatively fastidious and frequently
colonizes the upper airways so that false-negative and false-positive
cultures are common.

Prophylaxis and Treatment

Prophylaxis with H. influenzae type b (Hib) conjugate vaccine is advocated
for all children to be given in three doses at 2, 4, and 6 mo of age.

About 30% of H. influenzae strains produce -lactamase and are resistant
to       ampicillin.         Thus,       preferred        treatment       is
trimethoprim-sulfamethoxazole (TMP-SMX) 8/40 mg/kg/day po or IV for
children or 1 or 2 tablets of 160/800 mg bid for adults; cefuroxime 0.25
to 1 g IV q 6 h; cefaclor 40 mg/kg/day po in 3 divided doses for children
or 500 mg po q 6 h for adults; or doxycycline 100 mg po bid (contraindicated
in children <= 8 yr). Ampicillin 100 mg/kg/day IV in 4 divided doses
(maximum, 2 to 3 g/day) for children < 20 kg or 250 mg to 1 g q 6 h for
children > 20 kg and adults can be used to treat nonresistant strains.
Alternative regimens are amoxicillin 20 to 40 mg/kg po tid for children
< 20 kg or 250 to 500 mg po tid for children > 20 kg and adults.
Fluoroquinolones and azithromycin are also active.

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