Gram’s stains from pleural fluid samples were negative in 12 cases (52%); however, organisms were later cultured from 8 of these cases. Of the 19 positive cultures, 13 (68%) had exclusively aerobic bacteria, 2 (11%) had exclusively anaerobic bacteria, and 4 (21%) had both aerobic and anaerobic bacteria. All the isolated organisms are listed in Table 2. In the nine cases in which a single organism was isolated, more aerobic bacteria than anaerobic bacteria were found (seven vs two). Multiple organisms were cultured from the remaining 10 cases (average, 2.66 per patient). In 12 cases, blood cultures were positive (Table 2) and the most common organism culture growth was S aureus (5 cases). In five patients, a transthoracic needle aspiration biopsy (TNAB) was performed and nine bacteria were cultured with Gram-negative bacilli predominant (Table 2). Sixty-one organisms, including 46 aerobic bacteria and 15 anaerobic bacteria, were recovered, considering all samples (pleural fluid, blood, and TNAB samples). Only in three patients were all the cultures negative, including blood, pleural fluid, and TNAB samples; in seven cases, a single organism was isolated, and in the remainder, multiple organisms were cultured (range, 2 to 9; average, 3.38±2).
Sputum specimens were recovered in 13 patients, and only 3 were found to be positive. Isolated organisms never conformed to pleural isolation (1 Streptococcus pneumoniae, 1 Haemophilus influenzae, and 1 Mycobacterium tuberculosis). flovent inhaler

No drainage was instituted in five patients due to the scarcity of fluid (in one of these patients, repeated thoracentesis was sufficient). In the remaining 18 patients, closed chest drainage was maintained for an average of 14±14 days (range, 3 to 48 days), with an average drainage of 1,916± 1,883 mL (range, 140 to 7,000 mL). Hospital stays (34±19 vs 19.3±7 days; p=0.053) and drainage time (18±19 vs 5.8±4.4 days; p=0.1) were longer for empyemas with polymicrobial flora. In these patients, the diagnosis of endocarditis or thrombophlebitis (60% vs 31%; p=not significant [NS]) and bacteremia (60% vs 46%; p=NS) were more common.
Table 2—Bacterial Isolation in Pleural Fluid, Blood, and TNAB

Bacteria Pleural Fluid*

(19/23)

Bloodf

(12/23)

TNAB+

(5/5)

Aerobic bacteria Gram-positive cocci
S aureus 8 5 1
S pneumoniae 3
S pyogenes 2
S viridans 1
Staph coagulase negative 1 5
Gram-negative bacilli
P aeruginosa 3 1 1
Fseudomonas cepacia 1
A hydrophila 1
H influenzae 1 1 1
Haemophilus parainfluenzae 2
Escherichia coli 1
Enterobacter cloacae 1
Klebsiella pneumoniae 1 1
Unidentified Gram-negative 1
Other organisms
Branhamella catarrhalis 1
A Iwolfii 1
M tuberculosis 1
Anaerobic bacteria Gram-positive cocci
S intermedius 3 1 2
Streptococcus salivarius 2 1
Streptococcus sanguis 1
Peptococcus sp. 1
Peptostreptococcus sp 1
Gram-negative bacilli
Prevotella melaninogenica 1
Bacteroides uniformis 1
Fusobacterium sp 1
Total 35 17 9