Diagnosis of Pneumonia in Mechanically Ventilated Patients: Repeatability of the Protected Specimen Brush

Marquette, Charles Hugo; Hérengt, F.; Mathieu, Daniel; Saulnier, F.; Courcol, René; Ramon, P

doi:10.1164/ajrccm/147.1.211

Cited by 88 publications

(37 citation statements)

References 17 publications

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“…However, studies investigating the reproducibility and variability of bronchoscopic PSB have raised concerns about this technique. Timsit et al and Marquette et al repeated PSB sampling in the same lung subsegment and noted that results of quantitative cultures were on each side of the 10 3 -CFU/ml threshold in 16.7% to 13.6% of cases, respectively, with 59 to 67% of samples having CFU/ml counts varying by more than 10-fold (131,196). These investigators concluded that, as with all quantitative culturing techniques, borderline PSB quantitative culture results should be interpreted with caution.…”

Section: Microbiologic Diagnosismentioning

confidence: 99%

Ventilator-Associated Pneumonia: Diagnosis, Treatment, and Prevention

2006

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SUMMARY While critically ill patients experience a life-threatening illness, they commonly contract ventilator-associated pneumonia. This nosocomial infection increases morbidity and likely mortality as well as the cost of health care. This article reviews the literature with regard to diagnosis, treatment, and prevention. It provides conclusions that can be implemented in practice as well as an algorithm for the bedside clinician and also focuses on the controversies with regard to diagnostic tools and approaches, treatment plans, and prevention strategies.

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Section: Microbiologic Diagnosismentioning

confidence: 99%

Ventilator-Associated Pneumonia: Diagnosis, Treatment, and Prevention

2006

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“…MARQUETTE et al [13] found a 13.6% discordance in quantitative bacterial results, but there was a noticeable intrasubject variability (16%). TIMSIT et al [11] found similar results with a 24% discordance with regard to the recommended diagnostic threshold of 10 3 cfu?mL -1 .…”

Section: Discussionmentioning

confidence: 95%

“…PSB was first described by WIMBERLEY et al [8]. The transection of the PSB has been reported to be performed either at bedside [9 -11] or in the laboratory [12,13], where all the microbiological processing will be finally done. It may be assumed that differences in this procedure may influence the microbiological results.…”

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confidence: 99%

Diagnosis of nosocomial pneumonia in medical ward: repeatability of the protected specimen brush

et al. 2001

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The aims of this study were to assess the repeatability of two pairs of protected specimen brushes (PSB) done successively in the same lung area and either processed at the bedside or in the laboratory, and to provide a description of the bacteriological findings in 39 cases of suspected nosocomial pneumonia occurring in nonventilated patients.Four PSB were divided into two pairs. One pair of brushes (PB) was prepared at bedside and then sent to the laboratory; the other pair (PL) was immediately sent to the laboratory for complete processing.According to a 10 3 colony forming units (cfu)?mL -1 threshold, 49% out of 156 PSB were positive. Using the 10 3 cfu?mL threshold, the PL brushes were 89.7% concordant while the PB brushes were 76.9% concordant. The repeatability as expressed by K-value of the cultures of PSB was higher for PL brushes than for PB brushes (K-values of 0.795 and 0.537 respectively, p~0.12). Bacterial species were isolated in 58.3% of 156 PSB (176 isolates). In 14 cases, cultures of PSB disclosed more than one micro-organism in a concentration w10 3 cfu?mL -1 . The most frequently isolated organisms were Pseudomonas spp. (23.9%), Enterobacteriaceae (23.3%), Streptococcus spp. (21.6%) and Staphylococcus spp. (13.1%). Polymicrobial cultures were more frequent if the patient had a tracheostomy (seven out of the nine patients with a tracheostomy versus seven out of the 30 patients without a tracheostomy, pv0.01). Bacteriological discrepancies leading to a potential troublesome choice in antibiotherapy were observed in 31.8% of the patients for PL brushes and 56.5% of the patients for PB brushes.There is a low degree of repeatability of protected specimen brushes outside intensive care units which seem dependent on sampling processing. The distribution of pathogens found in case of suspicion of nosocomial pneumonia in nonventilated patients appears to be similar to that obtained in ventilator-associated pneumonia.

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“…Two studies [42,43] have found that a repeated PSB sampling in the same segmental area had a clear degree of variability, with 14% of culture spreading above and below the 10 3 cfu . mL -1 threshold in one study [42] and 40% of spreading in the other [43]. Finally, a bacterial bronchiolitis without pneumonia could also provide a false-negative result.…”

Section: Bronchoscopic Techniquesmentioning

confidence: 99%

“…The variability of the technique could provide also false-positive results. MARQUETTE et al [42] reported that 60% of patients had PSB results that varied by more than one log unit when ®ve PSB samplings were performed in the same patients and site. The bacterial colonization of the lower airways is frequent in patients with chronic obstructive pulmonary disease (COPD), bronchiectasis or prolonged antibiotic treatment, resulting in false-positive results of the sample obtained by PSB.…”

Section: Bronchoscopic Techniquesmentioning

confidence: 99%

Microbial investigation in ventilator-associated pneumonia

Ioanăş¹,

Ferrer²,

Angrill³

et al. 2001

Eur Respir J

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Ventilator-associated pneumonia (VAP) is a serious infectious condition in intensive care unit (ICU) patients, currently related to a high mortality rate. Therefore, this complication of mechanical ventilation requires a prompt diagnosis and adequate antibiotic treatment. The detection of the causative organism is imperative for guiding an appropriate therapy as there is strong evidence of the adverse effect of inadequate empirical treatment on outcome. The major difficulty of the microbial investigation is to obtain the sample from the lower respiratory tract, mainly because of the potential contamination with upper airways flora, which may result in a misinterpretation of the cultures.Microbial investigation in VAP is based on the culture of samples obtained from lower respiratory tract by noninvasive or invasive methods. The most common techniques of sampling are the endotracheal aspirate (ETA), which is considered a noninvasive method, the protected specimen brush (PSB) and the bronchoalveolar lavage (BAL), both being invasive methods of investigation. The latter were designed as an attempt to avoid the colonizing flora of the upper airways. The best of these diagnostic approaches is still controversial. In terms of outcome, there is strong evidence that the impact of both invasive and noninvasive methods seems to be similar. In terms of cost, however, the endotracheal aspirate is less expensive compared to BAL or PSB. On the other hand, invasive methods could be particularly beneficial in patients who are not responding to the initial empirical antibiotic treatment.The rationale for the quantitative culture of the respiratory samples is to differentiate between infection and colonization of lower airways, because the bacterial colonization is a frequent event in mechanically ventilated patients. The thresholds currently employed for the diagnosis of the pneumonia are the following: ETA samples, ≥105–106colony forming units (cfu)·mL−1; PSB samples, ≥103cfu·mL−1; and BAL samples, ≥104 cfu·mL−1.Intending to provide a practical approach to the issue, the present manuscript reviews the available noninvasive (blood culture, endotracheal aspirate) and invasive (protected specimen brush, bronchoalveolar lavage, blinded methods and lung biopsy) techniques used for the diagnosis of ventilator-associated pneumonia.

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Diagnosis of Pneumonia in Mechanically Ventilated Patients: Repeatability of the Protected Specimen Brush

Cited by 88 publications

References 17 publications

Ventilator-Associated Pneumonia: Diagnosis, Treatment, and Prevention

Ventilator-Associated Pneumonia: Diagnosis, Treatment, and Prevention

Diagnosis of nosocomial pneumonia in medical ward: repeatability of the protected specimen brush

Microbial investigation in ventilator-associated pneumonia

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