- Email: [email protected]
Bacteriology and beta-lactamase activity in acute exacerbation of chronic bronchitis
Original Report
Bacteriology and Beta-Lactamase Activity in Acute Exacerbation of Chronic Bronchitis Itzhak Brook, MD, MSc;* and Edith H. Frazier,MSc* ABSTRACT
Int J Infect
Objective: To assess the bacteriology of beta-lactamase (BL) enzyme activity in sputum of 40 patients with acute exacerbation of chronic bronchitis (AECB). Methods: The microbiology, BL production by the different isolates, and BL contents in the sputum were determined, Results: Eighty-four isolates were recovered (2.1 isolates per specimen), 44 aerobic and facultative (1 .I isolates per specimen), and 40 anaerobic (1 .O isolate per specimen). Aerobic bacteria were recovered in only 9 (225%) specimens, anaerobic bacteria in 9 (22.5%), and mixed aerobic and anaerobic bacteria were found in 22 (55%). The predominant aerobic isolates were Streptococcus pneumoniae (15 isolates), Haemophi/us influenzae (1 I), Moraxella catarrbalis and Klebsiella pneumoniae (4 each). The predominant anaerobes were Peptostreptococcus sp. (19) Prevotella sp. (1 l), and Fusobacterium sp.(6). Mixed flora were present in 25 (62.5%) specimens, and the number of isolates varied from 2 to 5 per specimen. Thirty-nine beta-lactamase-producing bacteria (BLPB) were isolated in 33 (82.5%) of the 40 cases. The predominant aerobic BLPB were H. influenzae, M. catarrhalis, K. pneumoniae, Staphylococcus aureus, and Escherichia co/i. The predominant anaerobic BLPB were Prevotella sp. and Fusobacterium sp. Beta-lactamase activity was detected in 26 (79%) of 33 of specimens in which BLPB were isolated, and in none of the seven specimens that did not harbor BLPB. Conclusions: The rapid detection of BL activity in sputum specimens may have implications for the antimicrobial management with AECB.
Key Words: acute exacerbation of chronic bronchitis, betalactamase, Fusobacterium sp., Haemophilus influenzae, Moraxella catarrhalis, Prevotella sp.
*Naval
Medical
Center,
Bethesda,
Maryland.
This work was conducted by federal whose work is in the public domain.
employees
of the US Government
The opinions and assertions contained herein are the private ones of the writers and are not to be construed as official or reflecting the views of the Navy Department or the Naval Service at large. Address correspondence Chase, MD 20813-0412.
74
to Dr. Itzhak Brook, P.0. Box E-mail: [email protected].
70412,
Chevy
Dis 2001;
5:74-77.
Antimicrobial therapy plays an important role in the management of acute exacerbation of chronic bronchitis (AECB), because bacteria may contribute to the perpetuation and exacerbation of the illness.’ The major organisms recovered from the sputum of patients with AECB are Streptococcus pneumoniae, Haemophilus injluenzae, and Moraxella catawbalis.1,2 Growing resistance through the production of the enzyme beta-lactamase (BL), may make the management of AECB more difficult. It has been hypothesized that beta-lactamase-producing bacteria (BLPB), can protect themselves as well as non-BLPB from penicillins.“,* Betalactamase activity previously has been detected in expectorated sputum of patients with lower respiratory tract infection,5-8 cystic fibrosis,’ and bronchitis.” However, the detection of BL activity was only correlated with the recovery of aerobic organisms (H. influenzae, M. catarrhalis, and Pseudomonas aeruginosa). The authors investigated the activity of BL in the sputum of patients of AECB, and correlated its presence with the recovery of aerobic as well as anaerobic bacteria in the expectorated sputum. PATIENTS
AND
METHODS
The study included 40 patients (31 males; 9 females). Their ages ranged from 39 to 83 years (average, 53 y). All patients had symptoms consistent with AECB, specifically, cough, substernal pain during respiration or cough, and fever. None had received antimicrobial therapy in the 6 weeks prior to inclusion in the study. However, all had received numerous courses of antibiotics for ABCB in the previous 2 years. Other inclusion criteria included a sputum smear with less than 10 squamous epithelial cells and more than 25 leukocytes per low-power field. Sputum specimens were plated, within 10 minutes of collection, on media supportive of growth of aerobic and anaerobic bacteria, as previously described.r2 Aerobic and anaerobic bacteria were identified by conventional methods. 13,‘*Beta-lactamase activity was determined for all isolates using the chromogenic cephalosporin analogue 87/312 method.15 Beta-lactamase activity in the sputum was determined by separating the supernatant by centrifugation for 15 minutes at 20,000 g. Beta-lactamase activity of the supernatant
75
Bacteriology and Beta-LactamaseActivity in Bronchitis / Brook and Frazier
Table
1. Organisms Isolated in 40 Expectorated Detection in Patients with Acute Bacterial
Sputum Specimens and Beta-Lactamase Exacerbation of Chronic Bronchitis Patient
isolated
1
Organisms
Aerobic organisms (n = 44) Haemophilus influenzae Moraxella catarrhalis Streptococcus pneumoniae Staphylococcus aureus Klebsiella pneumoniae Acinetobacter calcoaceticus Pseudomonas aeruginosa Escherichia co/i
activity
detected
- = non-beta-lactamase-producing
56
789
+
Number
10
+
+
+ -
77
12
13
14
15
16
77
18
-
+
19
+
20 +
+ -
-
+ +
+
+ + +
+
Anaerobic organisms (n = 40) Peptostreptococcus sp. Prevotella sp. Porphyromonas sp. Fusobacterium sp. Beta-lactamase
234
-
-
-
-
+
-
-
+
-
+
+ +
in sputum organism
Y
isolated;
Y
N
Y
Y
-
+
+
Y
+ = a beta-lactamase-producing
was assessed with nitrocefin (Glaxo, Middlesex, England), which turns red after exposure to BL. The reaction mixture consisted of nitrocefin dissolved in phosphate-buffered saline (pH, 7.2) at a concentmtion of 500 ug/mL. The nitro cefm solution (10 FL) was added to 10 PL of BL solution (Difco Laboratories, Detroit, MD or to 10 uL of pus supernatant. Negative controls contained 10 PL of nitrocefin plus 10 uL of either undiluted enzyme-negative sinus fluid supernatant or trypticase soy broth. A change from yellow to red usually became apparent within 5 to 12 minutes.
RESULTS Microorganisms were isolated from all specimens. Eightyfour isolates were recovered from the 40 patients (2.1 isolates per specimen), 44 aerobic and facultative (1.1 isolates per specimen), and 40 anaerobic (1.0 isolate per specimen) (Table 1). Aerobic bacteria were recovered in 9 (22.5) specimens, anaerobic bacteria in 9 (22.5%) and mixed aerobic and anaerobic bacteria were found (55%) (Table 2). The predominant aerobic isolates were Spneumoniae (15 isolates), H. infuenzae (1 l), M. cutarrhalis and Klebsiella pneumoniae (4 each), and Staphylococcus aureus and Escherichia coli (3 each). The predominant anaerobes were Peptostreptococcus sp. (19) Prevotella sp. (1 l), Fusobacterium sp. (6) and Porphyromonas sp. (4). Mixed flora were present in 25 (62.5%) specimens, in which the number of isolates varied from 2 to 5 per specimen. Single organisms were recovered from 15 (37.5%) specimens (see Table 1). Thirty-nine BLPB were isolated in 33 (82.5%) of the 40 cases (see Table 1). Twenty-four of the 44 (55%) aer-
N
Y organism
Y
YYYYNN
isolated:
NYYYY (table continues
Y = yes; N = No.
next page)
obic and facultative bacteria produced BL. The aerobic BLPB were H. influenzae (6/l 1,55%), M. catarrhalis and K. pneumoniae (4/4 in both), S. aureus and E. coli (3/3 in both), and Pseudomonas aeruginosa and Acinetobatter calcoaceticus (2/2 in both). Fifteen of the 40 (37.5%) anaerobic bacteria produced BL. The anaerobic BLPB were Prevotellu sp. (8/l 1,73%), Fusobacterium sp. (5/6,83%), and Porpbyromonas sp. (2/4,50%). Beta-lactamase activity was detected in 26 (79%) of the 33 specimens in which BLPB were isolated, and in none of the seven specimens that did not harbor BLPB (see Table 2). Of the 19 specimens that harbored aerobic BLPB only, BL activity was detected in 16 (84%); of the 9 that had anaerobic BLPB only, BL activity was found in 5 (55%) and BL activity was present in all 5 specimens that had both aerobic and anaerobic BLPB.
DISCUSSION This study confirms the findings of previous studies that demonstrate the recovery of S.pneumoniae, H. influenzae, M. catarrhalis, and Enterobacteriaceae from the Table
2. Beta-Lactamase Activity in Sputum Specimen in Relation to the Presence of Enzyme-Producing Bacteria Recovered from the Sputum
Type of BLPB isolates Recovered
Specimens (n = 40)
None detected Aerobic only recovered Anaerobic only Aerobic and anaerobic recovered
7 19 9
BLPB = beta-lactamase-producing
bacteria.
5
Specimens Lactamase Detected
in Which BetaActivity Was (n = 26) (78%) 0 16 5
(0) (84) (55)
5 (100)
76
International Journal of Infectious Diseases / Volume 5, Number 2,200l
Table 1. Detection
Organisms in Patients
Isolated in 40 Expectoratal Sputum with Acute Bacterial Exacerbation
Specimens of Chronic
Patient lsolafed
Organisms
21
Aerobic organisms (n = 44) Haemophilus influenzae Moraxella ca tarrhalis Streptococcus pneumoniae Staphylococcus aureus Klebsiella pneumoniae Acinetobacter calcoaceticus Pseudomonas aeruginosa Escherichia co/i
activity
detected
- = non-beta-lactamase-producing
23
24
25
26
27
28
+
29
30
Number 31
32
33
34
35
36
37
38
-
+
+
+
-
+
-
-
-
+
+
-
-
+
+
+
organism
isolated;
+
-
19 11
4
+
N
4 15 3 4 2 2 3
-
+
f
+
N
40
Total No. Bacteria (n = 84) 11
+
in sputum
39
-
-
Anaerobic organisms (n = 40) Peptostreptococcus sp. Prevotella sp. Porphyromonas sp. Fusobacterium sp. Beta-lactamase
22
and Beta-Lactamase Bronchitis (continued)
+
6
NYYYYYYYYNYNNYNYNN
+ = a beta-lactamase-producing
sputum of patients with AECB.‘z2However, it also demonstrates the isolation of anaerobic bacteria of oral flora origin in the sputum of over 75% of the patients. Anaerobic bacteria can colonize the bronchial tree, and are associated with pneumonia in children intubated after tracheostomy. l6 These organisms have also been associated with pulmonary infections of aspiration nature, which include aspiration pneumonia, lung abscesses, and emyema. 17,” Although the pathogenic role of these anaerobic bacteria in AECB is difficult to ascertain and their potential oral origin cannot be excluded, their ability to produce BL may contribute to the overall presence of this enzyme in the sputum. The recovery of BLPB is not surprising, since all of the patients in this study had multiple courses of antimicrobial therapy for previous episodes of AECB that might have selected for BLPB.‘” The ability to detect BL activity in the expectorated sputum in 26 (79%) of 33 specimens in which BLPB were isolated suggests that this enzyme not only is able to protect the BLPB but also can degrade penicillin in bronchial secretions, thus protecting penicillin-sensitive organisms. The rapid detection of BL activity in sputum specimens using available methods can be performed prior to recovery of organisms, which may take up to 48 hours. This testing can be performed even in locations where microbiologic laboratory services are not available, as may be the case in developing countries. Despite the common practice of treating an AECB with antimicrobial agents, the precise role of microbial pathogens is unclear. Because the lower respiratory tract of patients with chronic obstructive pulmonary disease (COPD) is frequently colonized with bacteria, the principal problem entails differentiating bronchial coloniza-
organism
isolated;
Y = yes; N = No.
tion from infection. Even when invasive diagnostic techniques (bronchoscopy with protected specimen brush) were used, a “significant quantity” of respiratory pathogens was found in approximately 50% of cases.‘.2 Because of the difficulty of distinguishing between bacterial and nonbacterial exacerbation, most patients have been treated with empirical antimicrobials directed against the most frequently isolated pathogens. The isolation of BLPB from sputum specimens of patients with AECB and the ability to actually measure the activity of the BL enzyme in the sputum raise the question of whether the treatment of AECB with beta-lactamase susceptible antibiotics is adequate in all instances, and whether therapy when indicated should be directed at the eradication of these organisms whenever they are present. Further studies that would evaluate the efficacy of antimicrobials effective against the recovered aerobic and anaerobic BLPB in AECB are warranted.
ACKNOWLEDGMENTS
The authors acknowledge the support of the staff of the Clinical Microbiology Laboratory Servicesat the Naval Medical Center, Bethesda, Maryland, and the secretarial assistance of Patricia Wojciechowski. REFERENCES
1. Monso E,Ruiz J,Rose11A, et al. Bacterial infection in chronic obstructive pulmonary disease.A study of stable and exacerbated outpatients using the protected specimen brush. Am J Respir Crit Care Med 1995; 152:1316-1320. 2. Soler N, Torres A, Ewig S,et al. Bronchial microbial patterns in severe exacerbations of chronic obstructive pulmonary
Bacteriology
and Beta-Lactamase
disease (COPD) requiring mechanical ventilation. Am J Respir Crit Care Med 1998; 157:1498-1505. 3. Brook I. The role of B-lactamase-producing bacteria in the persistence of streptococcal tonsillar infection. Rev Infect Dis 1984; 6:601-607. 4. Citri N. Beta-lactamase: lessons in the art of survival. J Chemother 1991; 3:75-78. 5. Stockley RA, Dragicevic P Burnet D, Hill SL. Role of beta-lactamases in response to pulmonary infections to amoxycillin/clavulanate. J Antimicrob Chemother 1989; 24(Suppl B):73-81. 6. Connell C, Aspinall S, Corkill J. Detection of B-lactamase in sputum. J Clin Path01 1994; 47:732-735. 7. Stefani S, Pellegrino MB, Russo G, Nicoletti G. Direct and indirect pathogenicity of beta-lactamase producing bacteria in respiratory tract infection in children. Role of cephalosporins resistant to enzymatic hydrolysis. Drugs 1991; 41(Suppl4):14-18. 8. Watanabe A, Oizumi K, Motomiya M. Beta-lactamase activity in sputum and indirect pathogenicity. Sci Rep Res Inst Tohoku Univ [Med] 1992; 38:2-4. 9. Giwercman B, Meyer C, Lambert PA, Reinert C, Hoiby N. High-level beta-lactamase activity in sputum samples from cystic fibrosis patients during antipseudomonal treatment. Antimicrob Agents Chemother 1992; 36:71-76. 10. Dmgicevic P Hill SL, Burnet D, Memkin D, Stockley RA. Activities and sources of beta-lactamase in sputum from patients with bronchiectasis. J Clin Microbial 1989; 27:1055-1061.
Activity in Bronchitis
/ Brook: and Frazier
77
11. Sportel JH, Koeter GH, van Altena R, Lowenberg A, Boersma WG. Relation between beta-lactamase producing bacteria and patient characteristics in chronic obstructive pulmonary disease (COPD). Thorax 1995; 50:249-253. 12. Brook I, Yocum P, Frazier EH. Bacteriology and beta-lactamase activity in acute and chronic maxillary sinusitis. Arch Otolaryngol Head Neck Surg 1996; 122:418-423. 13. Summanen P Barron EJ, Citron DM, Strong C, Wexler HM, Finegold SM. Wadsworth anaerobic bacteriology manual. 5th Ed. Belmont, CA: Star Publishing, 1993. 14. Murray PR, Baron EJ, Pfaller MA, Tenover FC, Yolken RH. Manual of clinical microbiology 6th Ed. Washington, DC: American Society for Microbiology, 1995. 15. O’Callaghan DH, Morris A, Kirby SM, Shingler AH. Novel method for detection of beta-lactamases by using a chromogenic cephalosporin substrate. Antimicrob Agents Chemother 1972; 1:283-288. 16. Brook I. Bacterial colonization, tracheobronchitis, and pneumonia following tracheostomy and long-term intubation in pediatric patients. Chest 1979; 76:420-424. 17. Brook I, Finegold SM. Bacteriology of aspiration pneumonia in children. Pediatrics 1980; 65: 1115- 1119. 18. Bartlett JG. Anaerobic bacteria infections of the lung and pleural space. Clin Infect Dis 1993; Ib(Suppl4):S248-S250. 19. Brook I, Gober AE. Emergence of beta-lactamase-producing aerobic and anaerobic bacteria in oropharynx of children following penicillin chemotherapy. Clin Pediatr 1984; 23:338-341.
Bacteriology and Beta-Lactamase Activity in Acute Exacerbation of Chronic Bronchitis Itzhak Brook, MD, MSc;* and Edith H. Frazier,MSc* ABSTRACT
Int J Infect
Objective: To assess the bacteriology of beta-lactamase (BL) enzyme activity in sputum of 40 patients with acute exacerbation of chronic bronchitis (AECB). Methods: The microbiology, BL production by the different isolates, and BL contents in the sputum were determined, Results: Eighty-four isolates were recovered (2.1 isolates per specimen), 44 aerobic and facultative (1 .I isolates per specimen), and 40 anaerobic (1 .O isolate per specimen). Aerobic bacteria were recovered in only 9 (225%) specimens, anaerobic bacteria in 9 (22.5%), and mixed aerobic and anaerobic bacteria were found in 22 (55%). The predominant aerobic isolates were Streptococcus pneumoniae (15 isolates), Haemophi/us influenzae (1 I), Moraxella catarrbalis and Klebsiella pneumoniae (4 each). The predominant anaerobes were Peptostreptococcus sp. (19) Prevotella sp. (1 l), and Fusobacterium sp.(6). Mixed flora were present in 25 (62.5%) specimens, and the number of isolates varied from 2 to 5 per specimen. Thirty-nine beta-lactamase-producing bacteria (BLPB) were isolated in 33 (82.5%) of the 40 cases. The predominant aerobic BLPB were H. influenzae, M. catarrhalis, K. pneumoniae, Staphylococcus aureus, and Escherichia co/i. The predominant anaerobic BLPB were Prevotella sp. and Fusobacterium sp. Beta-lactamase activity was detected in 26 (79%) of 33 of specimens in which BLPB were isolated, and in none of the seven specimens that did not harbor BLPB. Conclusions: The rapid detection of BL activity in sputum specimens may have implications for the antimicrobial management with AECB.
Key Words: acute exacerbation of chronic bronchitis, betalactamase, Fusobacterium sp., Haemophilus influenzae, Moraxella catarrhalis, Prevotella sp.
*Naval
Medical
Center,
Bethesda,
Maryland.
This work was conducted by federal whose work is in the public domain.
employees
of the US Government
The opinions and assertions contained herein are the private ones of the writers and are not to be construed as official or reflecting the views of the Navy Department or the Naval Service at large. Address correspondence Chase, MD 20813-0412.
74
to Dr. Itzhak Brook, P.0. Box E-mail: [email protected].
70412,
Chevy
Dis 2001;
5:74-77.
Antimicrobial therapy plays an important role in the management of acute exacerbation of chronic bronchitis (AECB), because bacteria may contribute to the perpetuation and exacerbation of the illness.’ The major organisms recovered from the sputum of patients with AECB are Streptococcus pneumoniae, Haemophilus injluenzae, and Moraxella catawbalis.1,2 Growing resistance through the production of the enzyme beta-lactamase (BL), may make the management of AECB more difficult. It has been hypothesized that beta-lactamase-producing bacteria (BLPB), can protect themselves as well as non-BLPB from penicillins.“,* Betalactamase activity previously has been detected in expectorated sputum of patients with lower respiratory tract infection,5-8 cystic fibrosis,’ and bronchitis.” However, the detection of BL activity was only correlated with the recovery of aerobic organisms (H. influenzae, M. catarrhalis, and Pseudomonas aeruginosa). The authors investigated the activity of BL in the sputum of patients of AECB, and correlated its presence with the recovery of aerobic as well as anaerobic bacteria in the expectorated sputum. PATIENTS
AND
METHODS
The study included 40 patients (31 males; 9 females). Their ages ranged from 39 to 83 years (average, 53 y). All patients had symptoms consistent with AECB, specifically, cough, substernal pain during respiration or cough, and fever. None had received antimicrobial therapy in the 6 weeks prior to inclusion in the study. However, all had received numerous courses of antibiotics for ABCB in the previous 2 years. Other inclusion criteria included a sputum smear with less than 10 squamous epithelial cells and more than 25 leukocytes per low-power field. Sputum specimens were plated, within 10 minutes of collection, on media supportive of growth of aerobic and anaerobic bacteria, as previously described.r2 Aerobic and anaerobic bacteria were identified by conventional methods. 13,‘*Beta-lactamase activity was determined for all isolates using the chromogenic cephalosporin analogue 87/312 method.15 Beta-lactamase activity in the sputum was determined by separating the supernatant by centrifugation for 15 minutes at 20,000 g. Beta-lactamase activity of the supernatant
75
Bacteriology and Beta-LactamaseActivity in Bronchitis / Brook and Frazier
Table
1. Organisms Isolated in 40 Expectorated Detection in Patients with Acute Bacterial
Sputum Specimens and Beta-Lactamase Exacerbation of Chronic Bronchitis Patient
isolated
1
Organisms
Aerobic organisms (n = 44) Haemophilus influenzae Moraxella catarrhalis Streptococcus pneumoniae Staphylococcus aureus Klebsiella pneumoniae Acinetobacter calcoaceticus Pseudomonas aeruginosa Escherichia co/i
activity
detected
- = non-beta-lactamase-producing
56
789
+
Number
10
+
+
+ -
77
12
13
14
15
16
77
18
-
+
19
+
20 +
+ -
-
+ +
+
+ + +
+
Anaerobic organisms (n = 40) Peptostreptococcus sp. Prevotella sp. Porphyromonas sp. Fusobacterium sp. Beta-lactamase
234
-
-
-
-
+
-
-
+
-
+
+ +
in sputum organism
Y
isolated;
Y
N
Y
Y
-
+
+
Y
+ = a beta-lactamase-producing
was assessed with nitrocefin (Glaxo, Middlesex, England), which turns red after exposure to BL. The reaction mixture consisted of nitrocefin dissolved in phosphate-buffered saline (pH, 7.2) at a concentmtion of 500 ug/mL. The nitro cefm solution (10 FL) was added to 10 PL of BL solution (Difco Laboratories, Detroit, MD or to 10 uL of pus supernatant. Negative controls contained 10 PL of nitrocefin plus 10 uL of either undiluted enzyme-negative sinus fluid supernatant or trypticase soy broth. A change from yellow to red usually became apparent within 5 to 12 minutes.
RESULTS Microorganisms were isolated from all specimens. Eightyfour isolates were recovered from the 40 patients (2.1 isolates per specimen), 44 aerobic and facultative (1.1 isolates per specimen), and 40 anaerobic (1.0 isolate per specimen) (Table 1). Aerobic bacteria were recovered in 9 (22.5) specimens, anaerobic bacteria in 9 (22.5%) and mixed aerobic and anaerobic bacteria were found (55%) (Table 2). The predominant aerobic isolates were Spneumoniae (15 isolates), H. infuenzae (1 l), M. cutarrhalis and Klebsiella pneumoniae (4 each), and Staphylococcus aureus and Escherichia coli (3 each). The predominant anaerobes were Peptostreptococcus sp. (19) Prevotella sp. (1 l), Fusobacterium sp. (6) and Porphyromonas sp. (4). Mixed flora were present in 25 (62.5%) specimens, in which the number of isolates varied from 2 to 5 per specimen. Single organisms were recovered from 15 (37.5%) specimens (see Table 1). Thirty-nine BLPB were isolated in 33 (82.5%) of the 40 cases (see Table 1). Twenty-four of the 44 (55%) aer-
N
Y organism
Y
YYYYNN
isolated:
NYYYY (table continues
Y = yes; N = No.
next page)
obic and facultative bacteria produced BL. The aerobic BLPB were H. influenzae (6/l 1,55%), M. catarrhalis and K. pneumoniae (4/4 in both), S. aureus and E. coli (3/3 in both), and Pseudomonas aeruginosa and Acinetobatter calcoaceticus (2/2 in both). Fifteen of the 40 (37.5%) anaerobic bacteria produced BL. The anaerobic BLPB were Prevotellu sp. (8/l 1,73%), Fusobacterium sp. (5/6,83%), and Porpbyromonas sp. (2/4,50%). Beta-lactamase activity was detected in 26 (79%) of the 33 specimens in which BLPB were isolated, and in none of the seven specimens that did not harbor BLPB (see Table 2). Of the 19 specimens that harbored aerobic BLPB only, BL activity was detected in 16 (84%); of the 9 that had anaerobic BLPB only, BL activity was found in 5 (55%) and BL activity was present in all 5 specimens that had both aerobic and anaerobic BLPB.
DISCUSSION This study confirms the findings of previous studies that demonstrate the recovery of S.pneumoniae, H. influenzae, M. catarrhalis, and Enterobacteriaceae from the Table
2. Beta-Lactamase Activity in Sputum Specimen in Relation to the Presence of Enzyme-Producing Bacteria Recovered from the Sputum
Type of BLPB isolates Recovered
Specimens (n = 40)
None detected Aerobic only recovered Anaerobic only Aerobic and anaerobic recovered
7 19 9
BLPB = beta-lactamase-producing
bacteria.
5
Specimens Lactamase Detected
in Which BetaActivity Was (n = 26) (78%) 0 16 5
(0) (84) (55)
5 (100)
76
International Journal of Infectious Diseases / Volume 5, Number 2,200l
Table 1. Detection
Organisms in Patients
Isolated in 40 Expectoratal Sputum with Acute Bacterial Exacerbation
Specimens of Chronic
Patient lsolafed
Organisms
21
Aerobic organisms (n = 44) Haemophilus influenzae Moraxella ca tarrhalis Streptococcus pneumoniae Staphylococcus aureus Klebsiella pneumoniae Acinetobacter calcoaceticus Pseudomonas aeruginosa Escherichia co/i
activity
detected
- = non-beta-lactamase-producing
23
24
25
26
27
28
+
29
30
Number 31
32
33
34
35
36
37
38
-
+
+
+
-
+
-
-
-
+
+
-
-
+
+
+
organism
isolated;
+
-
19 11
4
+
N
4 15 3 4 2 2 3
-
+
f
+
N
40
Total No. Bacteria (n = 84) 11
+
in sputum
39
-
-
Anaerobic organisms (n = 40) Peptostreptococcus sp. Prevotella sp. Porphyromonas sp. Fusobacterium sp. Beta-lactamase
22
and Beta-Lactamase Bronchitis (continued)
+
6
NYYYYYYYYNYNNYNYNN
+ = a beta-lactamase-producing
sputum of patients with AECB.‘z2However, it also demonstrates the isolation of anaerobic bacteria of oral flora origin in the sputum of over 75% of the patients. Anaerobic bacteria can colonize the bronchial tree, and are associated with pneumonia in children intubated after tracheostomy. l6 These organisms have also been associated with pulmonary infections of aspiration nature, which include aspiration pneumonia, lung abscesses, and emyema. 17,” Although the pathogenic role of these anaerobic bacteria in AECB is difficult to ascertain and their potential oral origin cannot be excluded, their ability to produce BL may contribute to the overall presence of this enzyme in the sputum. The recovery of BLPB is not surprising, since all of the patients in this study had multiple courses of antimicrobial therapy for previous episodes of AECB that might have selected for BLPB.‘” The ability to detect BL activity in the expectorated sputum in 26 (79%) of 33 specimens in which BLPB were isolated suggests that this enzyme not only is able to protect the BLPB but also can degrade penicillin in bronchial secretions, thus protecting penicillin-sensitive organisms. The rapid detection of BL activity in sputum specimens using available methods can be performed prior to recovery of organisms, which may take up to 48 hours. This testing can be performed even in locations where microbiologic laboratory services are not available, as may be the case in developing countries. Despite the common practice of treating an AECB with antimicrobial agents, the precise role of microbial pathogens is unclear. Because the lower respiratory tract of patients with chronic obstructive pulmonary disease (COPD) is frequently colonized with bacteria, the principal problem entails differentiating bronchial coloniza-
organism
isolated;
Y = yes; N = No.
tion from infection. Even when invasive diagnostic techniques (bronchoscopy with protected specimen brush) were used, a “significant quantity” of respiratory pathogens was found in approximately 50% of cases.‘.2 Because of the difficulty of distinguishing between bacterial and nonbacterial exacerbation, most patients have been treated with empirical antimicrobials directed against the most frequently isolated pathogens. The isolation of BLPB from sputum specimens of patients with AECB and the ability to actually measure the activity of the BL enzyme in the sputum raise the question of whether the treatment of AECB with beta-lactamase susceptible antibiotics is adequate in all instances, and whether therapy when indicated should be directed at the eradication of these organisms whenever they are present. Further studies that would evaluate the efficacy of antimicrobials effective against the recovered aerobic and anaerobic BLPB in AECB are warranted.
ACKNOWLEDGMENTS
The authors acknowledge the support of the staff of the Clinical Microbiology Laboratory Servicesat the Naval Medical Center, Bethesda, Maryland, and the secretarial assistance of Patricia Wojciechowski. REFERENCES
1. Monso E,Ruiz J,Rose11A, et al. Bacterial infection in chronic obstructive pulmonary disease.A study of stable and exacerbated outpatients using the protected specimen brush. Am J Respir Crit Care Med 1995; 152:1316-1320. 2. Soler N, Torres A, Ewig S,et al. Bronchial microbial patterns in severe exacerbations of chronic obstructive pulmonary
Bacteriology
and Beta-Lactamase
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