Are Quantitative Cultures Useful in the Diagnosis of Hospital ...

Are Quantitative Cultures Useful in the 

Diagnosis of Hospital-Acquired 

Pneumonia?* 

Gerry San Pedro, MD 

Noninvasive and invasive tests have been developed and studied for their utility in diagnosing and 

guiding the treatment of hospital-acquired pneumonia, a condition with an inherently high 

mortality. Early empiric antibiotic treatment has been shown to reduce mortality, so delaying this 

treatment until test results are available is not justifiable. Furthermore, tailoring therapy based 

on results of either noninvasive or invasive tests has not been clearly shown to affect morbidity 

and mortality. This may be related to quantitative limitations of these tests or possibly to a high 

false-negative rate in patients who receive early antibiotic treatment and may therefore have 

suppressed bacterial counts. Results of these tests, however, do influence treatment. It is 

therefore hoped that they may ultimately provide a rational basis for making therapeutic 

decisions. In the future, outcomes research should be a part of large-scale clinical trials, and 

noninvasive and invasive tests should be incorporated into the design in an attempt to provide a 

better understanding of the value of such tests. (CHEST 2001; 119:385S–390S) 

Key words: bacteriology; BAL; bronchoscopy; diagnosis; endotracheal aspiration; hospital-acquired pneumonia 

Abbreviations: APACHE acute physiology and chronic health evaluation; HAP hospital-acquired pneumonia; 

PSB protected specimen brushing; QEA quantitative endotracheal aspiration 

This article examines the utility of quantitative and 

qualitative (nonquantitative) cultures and of invasive 

and noninvasive techniques in the diagnosis of 

hospital-acquired pneumonia (HAP). I shall seek to 

address whether quantitative cultures are truly necessary 

and how important it is to identify a specific 

agent as a cause of the pneumonia. Ventilatorassociated 

pneumonia as well as hospital-acquired 

infections, in general, are considered. 

How good are we at making a diagnosis of HAP? 

Our clinical skills at making this diagnosis seem to be 

suboptimal at times. Consider the patient who is in 

the hospital and receiving mechanical ventilation and 

develops fever, leukocytosis, pulmonary infiltration 

on chest radiography, and purulent tracheobronchial 

secretions. In this clinical setting, we can certainly 

entertain a diagnosis of HAP. Andrews and colleagues1 

discussed this issue in patients with preexisting 

abnormal chest radiographic findings and 

symptomatology compatible with pneumonia. Their 

study1 utilized necropsy material to validate the 

*From the Department of Internal Medicine, Section of Pulmonary 

and Critical Care Medicine, Louisiana State University 

Health Sciences Center at Shreveport, Shreveport, LA. 

Correspondence to: Gerry San Pedro, MD, Section of Pulmonary 

and Critical Care Medicine, Louisiana State University Health 

Sciences Center at Shreveport, 1501 Kings Highway, PO Box 

33932, Shreveport, LA 71130-3932; e-mail: gerrsp@prysm.net 

Downloaded From: http://chestioumal.chestpubs.org/ on 07/03/2013 

presence or absence of pneumonia. It was demonstrated, 

however, that 29% of these cases were 

misdiagnosed clinically. 1 Other conditions, such as 

“pulmonary fibroproliferation,” sinusitis, cholecystitis, 

and various noninfectious conditions, can also 

produce findings that might suggest the presence of 

pneumonia. 2 Similarly, the chest radiograph may be 

misleading at times. 3 In the report by Andrews and 

colleagues, 1 36% of patients had pneumonia at necropsy, 

even though their chest radiographs may not 

have changed. Work from our own group 4,5 has also 

clearly shown that there are many other potentially 

lethal conditions that can create a picture resembling 

pneumonia. Access to pulmonary tissue for making a 

histologic diagnosis would clearly be a desirable 

objective. The histopathologic findings that characterize 

nosocomial pneumonia have been described in 

detail. 6 

Diagnosis of HAP 

Clinical findings and chest radiography alone may 

not always suffice for making a definitive diagnosis of 

pneumonia. However, we can attempt to make a 

diagnosis by examining respiratory secretions. The 

number of organisms present in an infection, which 

may in turn be dependent on the virulence of the 

CHEST / 119 /2/FEBRUARY, 2001 SUPPLEMENT 385S

organism and the host’s response, is of prime importance. 

How many organisms must be detected to 

assume the presence of infection vs mere colonization? 

Johanson and colleagues 7 have suggested that 

about 10 3 cfu/g of tissue indicate the presence of 

infection, although this could depend on the type of 

bacteria present. Tissue is often not available, however, 

and counts may have to be obtained in secretions. 

In this case, about 10 5 bacteria per milliliter 

of exudate may have similar import. 8 Sources of 

sampling for making a diagnosis include blood and 

other body fluids as well as several techniques 

available for obtaining samples. These techniques 

include needle aspiration, endotracheal aspiration, 

and both blind and invasive procedures to obtain 

bronchial secretions (Table 1). 

Percutaneous Needle Aspiration 

How useful in general is percutaneous needle 

aspiration? As noted above, much depends on the 

bacterial counts in the area being aspirated. 9 The 

sensitivity of the technique for patients who are not 

receiving mechanical ventilation is about 60%, 10 with 

the figure somewhat lower (approximately 40%) for 

patients receiving mechanical ventilation. 11 Thus, 

the procedure may prove to be less useful in the 

population of patients in which it is most needed. 

From the standpoint of predictive value, a positive 

test result is helpful, but a negative test result may 

not be helpful since about a third of patients with a 

negative test result may actually have the disease. 10 

The main objection to percutaneous needle aspiration 

is the high incidence of complications, including 

hemorrhage, hemoptysis, and pneumothorax. This is 

true even though the procedure itself may be fairly 

easy to carry out. The incidence of pneumothorax is 

about 20%, but may be up to 60% in patients 

receiving mechanical ventilation. 12 About half of 

these patients will require a chest tube. 

Endotracheal Aspiration 

Results of endotracheal aspiration may be compared 

with those of other invasive and noninvasive 

Table 1—Diagnostic Techniques 

Blood, Pleural Fluid Analysis, and Cultures 

Nonbronchoscopic evaluations 

● Percutaneous needle aspiration 

● Endotracheal aspiration 

● Blind bronchial sampling 

Bronchoscopic techniques 

● PSB 

● BAL 

Tissue diagnosis 

techniques (Table 2), including open-lung biopsy, 

postmortem lung cultures, blood and pleural fluid 

analysis, and protected specimen brushing (PSB) 

and BAL. 13 Sensitivity and specificity of routine 

endotracheal aspiration have a broad scatter in relation 

to these other measurements, with sensitivity 

ranging from 57 to 88%, but with specificity in a 

relatively low range, from 0 to 33%. Thus, nonquantitative 

endotracheal cultures may have limited utility. 

One of the chief values of endotracheal cultures 

is that they exclude certain types of infection when 

the organism is absent. For example, absence of 

Pseudomonas in an endotracheal aspirate makes it 

unlikely that this organism is the cause of an infection. 

Attempts have also been made to perform 

quantitative endotracheal aspiration (QEA). Jourdain 

and colleagues 14 have attempted to establish a 

cutoff for assigning significance to colony counts in 

endotracheal aspirates by examining sensitivity, specificity, 

and overall accuracy (Table 3). They concluded 

that a level of 10 5 to 10 6 bacteria per milliliter 

of exudate was optimal for diagnostic purposes. 

Although counts higher than this figure improved 

specificity, there was an unacceptable decline in 

sensitivity. 

Noninvasive Techniques 

Can noninvasive techniques that can be conducted 

at the bedside be used to obtain bronchial samples? 

We can employ blind bronchial sampling, 15 blind 

BAL fluid sampling, 16 or blind performance of 

PSB. 17 We know somewhat more about the sensitivity 

and specificity of these techniques. For blind 

bronchial sampling, the sensitivity is about 80%; for 

blind BAL, the sensitivity is about 73% with a 

specificity of 96%. The figures are also good for blind 

PSB, at 66% and 91%, respectively, and with a high 

diagnostic yield (66%) and good concordance with 

bronchofibroscopic PSB (85%). 17 Then why not use 

these techniques routinely? Unfortunately, they are 

relatively new, and experience with their use is 

limited. These procedures, however, may have considerable 

utility in the future since they are easy to 

perform; in some centers, the specimens are even 

obtained by respiratory technicians. 

PSB 

PSB is a standard invasive method for diagnosing 

HAP. The brush is small and obtains a sample in the 

range of 0.001 mL. After the sample is obtained, it is 

diluted in about 1 mL of transport medium, an 

approximately 1,000-fold dilution. 18 Consequently, 

386S Hospital-Acquired Infections: Realities of Risks and Resistance 

Downloaded From: http://chestioumal.chestpubs.org/ on 07/03/2013

the standards for colony counts must be appropriately 

adjusted, and counts of 10 3 cfu/mL of transport 

medium would be considered diagnostic. Overall, 

this technique has about 82% sensitivity and 89% 

specificity. 19 However, the repeatability of this procedure 

in the same patient is not perfect, and 

quantitative discordance may be considerable. 20,21 

Another problem with this technique and others 

already discussed is that colony counts fall in patients 

previously treated with antibiotics. 22,23 The incidence 

of such treatment is high, and most patients 

entering the intensive-care environment are already 

being treated with one or more antibiotics. However, 

PSB could play a role in identifying patients with 

recurrent or resistant infection. In a study by Montravers 

and colleagues, 24 76 patients with positive 

specimen findings who were treated with antibiotics 

were restudied 3 days later. Of 173 organisms originally 

identified, 11 organisms (6%) were shown to 

be still present, 3 of which were in significant 

numbers. However, 32 new organisms were also 

identified, 9 of which were in significant numbers. 

Resistance was observed in 26 of these 32 organisms 

(81%). Thus, a total of 12 old or new organisms were 

noted to be present in significant numbers, and resistance 

did appear to represent a problem. Of the 9 

patients with significant numbers of new organisms, 

only 44% subsequently responded to treatment; however, 

in the other 67 patients, the response was 93%, a 

highly significant difference. Thus, perhaps there may 

be a role for repeating PSB in the setting of poorly 

responding patients. However, further studies need to 

Table 3—Value of Endotracheal Aspirates With 

Quantitative Cultures* 

Threshold, 

cfu/mL 

Sensitivity, 

% 

Table 2—Value of Endotracheal Aspirates With Routine Cultures* 

Source No. Sensitivity, % Specificity, % Reference 

Hill et al34 48 82 27 Open-lung biopsy, blood, pleural fluid 

Berger and Arango35 19 74 Postmortem lung 

Villers et al36 17 88 0 Blood, pleural fluid, open-lung biopsy, serology 

Torres et al27 41 57 14 PSB, BAL 

Lambert et al37 *Adapted from Meduri. 

22 88 33 PSB 

13 

Specificity, 

% 

Overall 

Accuracy, 

% 

10 3 

86 52 61 

10 4 

71 57 61 

10 5 

71 88 75 

10 6 

71 86 82 

10 7 

43 95 82 

*Adapted from Jourdain et al. 14 


document that repeating PSB in these patients results 

in changes in management that lead to improved 

outcomes. 

BAL 

How effective is BAL as a diagnostic tool? This 

technique samples a large number (approximately 

10 6 ) of alveoli and can recover a larger number of 

organisms. The threshold is in the range of 10 4 

organisms per milliliter of lavage fluid, which is 

equivalent to 10 6 organisms per milliliter of alveolar 

fluid from the periphery. 25 Sensitivity and specificity 

are high, in the range of 72 to 100% for sensitivity 

and 69 to 100% for specificity. 13 Qualitatively, the 

same organisms are recovered repeatedly in the 

range of 95%, but as in the case with PSB, there is 

considerable quantitative discordance. 26 Sensitivity 

and specificity of BAL have also been compared with 

those of PSB (Table 4), and the results are comparable. 

The question also arises about the comparability 

of results of PSB vs BAL in patients already 

receiving antibiotics. As can be seen in Table 5, 13 the 

range was broad, but the two studies 27,28 in patients 

receiving antibiotics showed values similar to the two 

studies 29,30 in patients not receiving antibiotics. In 

general, however, the yield of organisms is believed 

to be lower in patients receiving antibiotics than in 

those not receiving antibiotics. 

Outcomes Research 

Treatment outcome is an important consideration 

in determining whether invasive or noninvasive 

Source 

Table 4—Comparison of PSB and BAL* 

Sensitivity, 

% 

PSB BAL 

Specificity, 

% 

Sensitivity, 

% 

Specificity, 

% 

Chastre et al38 100 60 

Vallés et al39 67 96 

Chastre et al19 82 89 91 78 

Marquette et al25 58 89 47 100 

*Adapted from Meduri. 13 


Source 

No. With 

Pneumonia/ 

Total 

Undergoing 

Antibiotic 

Therapy, % 

methods are best for obtaining specimens for bacterial 

culture. Does making a specific etiologic diagnosis 

make a difference in outcome? Do results of 

culture techniques influence antibiotic choices and, 

ultimately, outcome? Does the use of a quantitative 

technique result in improved outcomes compared 

with nonquantitative techniques? 31 

Many efforts have been made to compare the 

bacteriology of quantitative vs nonquantitative techniques; 

some research is beginning to address patient 

outcomes as well. Luna and colleagues 32 from 

Argentina investigated outcomes in 132 patients with 

ventilator-associated pneumonia who underwent 

BAL within 24 h of clinical diagnosis. Of this number, 

107 patients (81%) were previously receiving 

antibiotics. Using the criterion of 10 4 cfu/mL as a 

cutoff, 65 of the 132 patients (49%) had positive 

findings; of this number, 46 patients (71%) died. 

However, mortality did not differ significantly in 

patients who either had or had not previously received 

antibiotics, in those with positive vs negative 

findings by BAL, or in those whose antibiotic regimen 

was changed after the lavage procedure. A 

significantly lower mortality was found in patients 

who were deemed to have received adequate vs 

inadequate therapy before their procedure (38% vs 

91%). In patients receiving no antibiotic therapy 

before the procedure, mortality was 60%. It is also 

noteworthy that half of the mortality in this study in 

patients with positive BAL findings was experienced 

within 48 h of the procedure, before culture results 

were available, so that this information could not 

always be used to direct therapy. In this study, early 

initiation of adequate therapy for ventilator-associated 

pneumonia reduced mortality, although overall 

mortality was high and not influenced by culture 

results or by switching antibiotics based on these 

results. Also, if therapy is delayed until bronchoscopy 

is performed or while awaiting BAL results, mortality 

is higher. 32 

In a second study from Spain, Sanchez-Nieto and 

colleagues 33 studied 51 patients who were randomly 

classified into two groups. One group received extensive 

investigation, including QEA, BAL, and PSB; 

Table 5—Comparison of PSB and BAL* 

Qualitative 

Concordance, % 

Quantitative 

Concordance, % Reference 

Chastre et al29 5/21 0 50 38 Blood cultures, clinical response, histology 

Torres et al27 25/34 100 78 57 Blood cultures, clinical response, histology 

Violán et al28 25/45 52 57 54 Blood cultures, clinical response, histology 

Jiménez et al30 28/40 0 97 93 Blood cultures, clinical response 

*Adapted from Meduri. 13 

the other group received only QEA. Of the 24 

patients in the first group, 16 patients (67%) had 

positive findings by both QEA and BAL and 14 

patients by PSB (58%), although there were substantial 

within-patient inconsistencies. In this group, 10 

of the patients (42%) had their regimens modified as 

the result of testing, and overall mortality was 11 of 

24 patients (46%). In the second group of 27 patients, 

QEA findings were positive in 20 patients 

(74%), 4 of 27 patients had their regimens modified, 

and the mortality was 7 of 27 patients (26%). Although 

more patients in the extensively tested group 

had their regimens modified after testing, the difference 

in mortality between the two groups was not 

significant. A potentially confounding factor in this 

study, however, was that a much higher percentage 

of the first group had culture findings that were positive 

for Pseudomonas, an organism known to be associated 

with a high mortality. Despite the more frequent 

change in antibiotic regimen in the former group, the 

authors concluded that there was no substantial difference 

in mortality between patients undergoing intensive, 

compared with less intensive, investigation, although 

the numbers in the study were too small to 

warrant drawing strong conclusions. 

Despite the fact that neither of these two studies 

provides strong evidence favoring an aggressive diagnostic 

approach in HAP, they are indicative of the 

type of investigations needed to improve our understanding 

and treatment of this condition. The database 

regarding sensitivity and specificity of invasive 

and noninvasive tests is now well characterized. We 

should begin to direct our energies toward determining 

the outcomes of applying these therapies. 

Appendix 

Dr. George Eliopoulos: You have convinced me of 

the difficulty of using this kind of information to 

make clinical decisions. However, let me ask this 

question: If you were to design a study to show 

superiority of one regimen over another for the 

treatment of pneumonia, what would you demand of 



the investigators for making as ironclad as possible a 

definition of nosocomial pneumonia or ventilatorassociated 

pneumonia? 

Dr. Gerry San Pedro: You can define nosocomial 

pneumonia in various ways, but what most investigators 

are seeking is to know that they are studying 

comparable groups of patients in the different arms 

of their studies. 

Dr. Eliopoulos: Not entirely true. For example, if 

you have 1,000 patients in both arms, and 999 of 

them have viral pneumonia, the groups are comparable. 

But what I want to know is how many patients 

have Pseudomonas infection and how many have 

pneumococcal infection, etc. These definitions, from 

my point of view, are crucial. 

Dr. David Bowton: The key question is how to 

deal with the disquieting information concerning 

histology, BAL, PSB, correlates, and reclassification. 

There is no correlation between any of our diagnostic 

studies whether you use pathology or quantitative 

culture, and if you use different criteria for histologic 

analysis, you reclassify 30% of the patients. Coming 

up with a clinically relevant diagnostic schema at the 

moment seems almost impossible, and we must 

accept that we often simply cannot make the diagnosis. 

One approach is to simply pick criteria that are 

reproducible, obtain whatever microbiological information 

is available, accept that the method might be 

flawed, and then consistently apply it to all patients. 

There must also be a large enough patient population 

to achieve adequate power for subgroup analysis 

to detect outcome differences. This will, to some 

extent, avoid the question of whether the microbiology 

is sufficiently accurate. The microbiological classification 

can initially be considered a matter that is 

primarily of academic interest but may, in addition, 

provide some scientific underpinning if patients have 

comparable microbiology. The key feature is a large 

sample size. Patients can also be matched in other 

ways, such as having comparable APACHE (acute 

physiology and chronic health evaluation) scores. 

However, the mortality level in a large group is the key. 

Dr. Eliopoulos: What criteria would you use? 

Dr. San Pedro: I would employ a mix. There 

would have to be both clinical criteria and invasive 

techniques. Personally, I would use BAL. 

Dr. David Weber: One must be careful about taking 

risk profiles that have been developed in one group 

of patients and assuming they will work in another 


group. We evaluated the risk factors for ventilatorassociated 

pneumonia in elderly patients admitted to 

either a medical ICU or surgical ICU. APACHE II 

scores, which were developed and validated in surgical 

patients, were predictive for the development 

of pneumonia in elderly persons in our surgical ICU 

but were not predictive for elderly persons in our 

medical ICU. Another point regarding resistance, 

which will have a major impact on the development 

of resistance, is knowing which antibiotic a patient 

might have been taking before pneumonia developed. 

Dr. Louis Rice: I have a question about the 

adjustments that were made in the antibiotic regimen. 

Was the therapy narrowed to target specific 

organisms or was it expanded to deal with resistant 

organisms? 

Dr. San Pedro: That was not dealt with in the 

article by Sanchez-Nieto et al. 33 

Dr. Bowton: In a study 40,41 that was similar to the 

study by Luna et al, 32 when antibiotic therapy was 

discontinued based on BAL, there was a low mortality, 

only 14%. 

Dr. San Pedro: The goal there was to narrow down 

antibiotic coverage, but in most hospitals, I suspect 

the practice would be to expand coverage by adding 

an antibiotic. 

Dr. Rice: None of these would be techniques that 

would prevent physicians from narrowing down therapy. 

Dr. Steve Nelson: In a patient doing poorly in the 

ICU receiving broad-spectrum therapy, I will often 

send an endotracheal aspirate, and if it returns in 2 to 

3 days without showing a suspected pathogen, I will 

often trim back my therapy. This has not been 

studied very carefully, however. 

Dr. Bowton: That should be a part of the study 

design. A study should have a standardized initial 

empiric approach and then perhaps be modified 

subsequently based on findings from testing such as 

QEA. Although some have argued that this may not 

lead to a difference in outcome, if you employ an 

empiric approach and narrow it back, there may be 

new information. 

References 

1 Andrews CP, Coalson JJ, Smith JD, et al. Diagnosis of 

nosocomial bacterial pneumonia in acute, diffuse lung injury. 

Chest 1981; 80:254–258 

2 Meduri GU, Mauldin GL, Wunderink RG, et al. Causes of 


fever and pulmonary densities in patients with clinical manifestations 

of ventilator-associated pneumonia. Chest 1994; 

106:221–235 

3 Wunderink RG, Woldenberg LS, Zeiss J, et al. The radiologic 

diagnosis of autopsy-proven ventilator-associated pneumonia. 

Chest 1992; 101:458–463 

4 San Pedro GS, McCracken G, Campbell GD. 61% of deaths 

in pneumonia are potentially preventable [abstract]. Am Rev 

Respir Dis 1989; 139:A428 

5 San Pedro GS, Briery C, Whitson B, et al. The clinical 

diagnosis of pneumonia is a poor predictor for an attributable 

cause of death [abstract]. Am J Respir Crit Care Med 1998; 

157:A292 

6 Coalson JJ. The pathology of nosocomial pneumonia. Clin 

Chest Med 1995; 16:13–28 

7 Johanson WG Jr, Seidenfeld JJ, Gomez P, et al. Bacteriologic 

diagnosis of nosocomial pneumonia following prolonged mechanical 

ventilation. Am Rev Respir Dis 1988; 137:259–264 

8 Bartlett JG, Finegold SM. Bacteriology of expectorated sputum 

with quantitative culture and wash technique compared 

to transtracheal aspirates. Am Rev Respir Dis 1978; 117: 

1019–1027 

9 San Pedro GS, Campbell GD, Tryka AF. Factors affecting the 

sensitivity of needle aspiration in a rodent model of Gramnegative 

bacillary pneumonia. Chest 1989; 95:198S–199S 

10 Dorca J, Manresa F, Esteban L, et al. Efficacy, safety, and 

therapeutic relevance of transthoracic aspiration with ultrathin 

needle in nonventilated nosocomial pneumonia. Am J 

Respir Crit Care Med 1995; 151:1491–1496 

11 Torres A, Jiménez P, Puig de la Bellacasa J, et al. Diagnostic 

value of nonfluoroscopic percutaneous lung needle aspiration 

in patients with pneumonia. Chest 1990; 98:840–844 

12 Mayhall CG. Nosocomial pneumonia: diagnosis and prevention. 

Infect Dis Clin North Am 1997; 11:427–457 

13 Meduri GU. Diagnosis and differential diagnosis of ventilator-associated 

pneumonia. Clin Chest Med 1995; 16:61–93 

14 Jourdain B, Novara A, Joly-Guillou M-L, et al. Role of 

quantitative cultures of endotracheal aspirates in the diagnosis 

of nosocomial pneumonia. Am J Respir Crit Care Med 

1995; 152:241–246 

15 Papazian L, Thomas P, Garbe L, et al. Bronchoscopic or blind 

sampling techniques for the diagnosis of ventilator-associated 

pneumonia. Am J Respir Crit Care Med 1995; 152:1982–1991 

16 Pugin J, Auckenthaler R, Mili N, et al. Diagnosis of ventilatorassociated 

pneumonia by bacteriologic analysis of bronchoscopic 

and nonbronchoscopic “blind” bronchoalveolar lavage 

fluid. Am Rev Respir Dis 1991; 143:1121–1129 

17 Bello S, Tejada A, Chacón E, et al. “Blind” protected 

specimen brushing versus bronchoscopic techniques in the 

aetiological diagnosis of ventilator-associated pneumonia. Eur 

Respir J 1996; 9:1494–1499 

18 Marquette C-H, Ramon P, Courcol R, et al. Bronchoscopic 

protected catheter brush for the diagnosis of pulmonary 

infections. Chest 1988; 93:746–750 

19 Chastre J, Fagon J-Y, Bornet-Lesco M, et al. Evaluation of 

bronchoscopic techniques for the diagnosis of nosocomial 

pneumonia. Am J Respir Crit Care Med 1995; 152:231–240 

20 Marquette CH, Herengt F, Mathieu D, et al. Diagnosis of 

pneumonia in mechanically ventilated patients: repeatability 

of the protected specimen brush. Am Rev Respir Dis 1993; 

147:211–214 

21 Timsit J-F, Misset B, Francoual S, et al. Is protected specimen 

brush a reproducible method to diagnose ICU-acquired 

pneumonia? Chest 1993; 104:104–108 

22 Marrie TJ. Community-acquired pneumonia. Clin Infect Dis 

1994; 18:501–515 

23 Örtqvist Å, Kalin M, Lejdeborn L, et al. Diagnostic fiberoptic 

bronchoscopy and protected brush culture in patients with 

community-acquired pneumonia. Chest 1990; 97:576–582 

24 Montravers P, Fagon J-Y, Chastre J, et al. Follow-up protected 

specimen brushes to assess treatment in nosocomial 

pneumonia. Am Rev Respir Dis 1993; 147:38–44 

25 Marquette CH, Copin M-C, Wallet F, et al. Diagnostic tests 

for pneumonia in ventilated patients: prospective evaluation 

of diagnostic accuracy using histology as a diagnostic gold 

standard. Am J Respir Crit Care Med 1995; 151:1878–1888 

26 Gerbeaux P, Ledoray V, Boussuges A, et al. Diagnosis of 

nosocomial pneumonia in mechanically ventilated patients: 

repeatability of the bronchoalveolar lavage. Am J Respir Crit 

Care Med 1998; 157:76–80 

27 Torres A, Puig de la Bellacasa J, Xaubet A, et al. Diagnostic 

value of quantitative cultures of bronchoalveolar lavage and 

telescoping plugged catheters in mechanically ventilated patients 

with bacterial pneumonia. Am Rev Respir Dis 1989; 

140:306–310 

28 Violán JS, de Castro FR, Luna JC, et al. Comparative efficacy 

of bronchoalveolar lavage and telescoping plugged catheter in 

the diagnosis of pneumonia in mechanically ventilated patients. 

Chest 1993; 103:386–390 

29 Chastre J, Fagon J-Y, Soler P, et al. Diagnosis of nosocomial 

bacterial pneumonia in intubated patients undergoing ventilation: 

comparison of the usefulness of bronchoalveolar lavage 

and the protected specimen brush [published erratum appears 

in Am J Med 1989; 86:258]. Am J Med 1988; 85:499– 

506 

30 Jiménez P, Saldías F, Meneses M, et al. Diagnostic fiberoptic 

bronchoscopy in patients with community-acquired pneumonia. 

Chest 1993; 103:1023–1027 

31 Wunderink RG. Mortality and the diagnosis of ventilatorassociated 

pneumonia: a new direction. Am J Respir Crit Care 

Med 1998; 157:349–350 

32 Luna CM, Vujacich P, Niederman MS, et al. Impact of BAL 

data on the therapy and outcome of ventilator-associated 

pneumonia. Chest 1997; 111:676–685 

33 Sanchez-Nieto J-M, Torres A, Garcia-Cordoba F, et al. 

Impact of invasive and noninvasive quantitative culture sampling 

on outcome of ventilator-associated pneumonia: a pilot 

study. Am J Respir Crit Care Med 1998; 157:371–376 

34 Hill JD, Ratliff JL, Parrott JCW, et al. Pulmonary pathology in 

acute respiratory insufficiency: lung biopsy as a diagnostic 

tool. J Thorac Cardiovasc Surg 1976; 71:64–71 

35 Berger R, Arango L. Etiologic diagnosis of bacterial nosocomial 

pneumonia in seriously ill patients. Crit Care Med 1985; 

13:833–836 

36 Villers D, Derriennic M, Raffi F, et al. Reliability of the 

bronchoscopic protected catheter brush in intubated and 

ventilated patients. Chest 1985; 88:527–530 

37 Lambert RS, Vereen LE, George RB. Comparison of tracheal 

aspirates and protected brush catheter specimens for identifying 

pathogenic bacteria in mechanically ventilated patients. 

Am J Med Sci 1989; 297:377–382 

38 Chastre J, Viau F, Brun P, et al. Prospective evaluation of the 

protected specimen brush for the diagnosis of pulmonary 

infections in ventilated patients. Am Rev Respir Dis 1984; 

130:924–929 

39 Vallés J, Rello J, Fernández R, et al. Role of bronchoalveolar 

lavage in mechanically ventilated patients with suspected pneumonia. 

Eur J Clin Microbiol Infect Dis 1994; 13:549–558 

40 Guerra LF, Baughman RP. Use of bronchioalveolar lavage to 

diagnose bacterial pneumonia in mechanically ventilated 

patients. Crit Care Med 1990; 18:169–173 

41 Fagon JY, Chastre J, Hance AJ, et al. Nosocomial pneumonia 

in ventilated patients: a cohort study evaluating attributable 

mortality and hospital stay. Am J Med 1993; 94:281–299

Are Quantitative Cultures Useful in the Diagnosis of Hospital ...

Create successful ePaper yourself

Delete template?

Save as template?