Bronchoalveolar Lavage Culture Research Articles

The agreement between bronchoalveolar lavage, bronchial wash and sputum culture: a retrospective study.

Bronchoalveolar lavage is commonly used in clinical practice for unresolved pneumonia. However, bronchoalveolar lavage is not suitable for all patients as it is an invasive procedure and can worsen oxygenation. The diagnostic value of bronchial wash and sputum has been debated extensively over the years. In this study, we aim to compare the diagnostic value in several pathogens of bronchoalveolar lavage and bronchial wash, and secondarily bronchoalveolar lavage and sputum. We retrospectively included all adult patients in our hospital who underwent bronchoalveolar lavage, bronchial wash, and where sputum sampling was done between January 1st of 2018 and December 31st of 2021. The intraclass correlation coefficient was computed for the three tests. In total, 308 patients were included. We found a level of correlation of 0.819 and 0.865, respectively, between bronchoalveolar lavage and bronchial wash for two pathogens: Staphylococcus aureus and Pseudomonas aeruginosa. For Stenotrophomonas maltophilia and Aspergillus fumigatus, we found an intraclass correlation coefficient of 0.568 and 0.624, respectively. Between bronchoalveolar lavage and sputum, we found varying levels of agreement. Our study shows reasonably well agreement levels between bronchoalveolar lavage and bronchial wash, suggesting that bronchial wash could potentially be an alternative to bronchoalveolar lavage.

Experience of flexible bronchoscopy in the pediatric pulmonary diseases clinic.

Flexible bronchoscopy is a valuable method in the diagnosis and treatment of respiratory tract diseases in children. This study aimed to examine the indications for and results of flexible bronchoscopy in children. The study included patients aged 0-18 years who underwent flexible bronchoscopy between 1 January 2017 and 31 December 2022. The patients were evaluated for demographic characteristics, indications for bronchoscopy, comorbidities, bronchoscopy findings, and the results of bronchoalveolar lavage. During the defined study period, a total of 410 flexible bronchoscopy procedures were performed. 51.9% of the patient population were male, and 48.1% were female, with a mean age of 96.93 ± 63.45 months. The most common indication for flexible bronchoscopy was recurrent lower respiratory tract infection (26.8%), followed by chronic cough (19.1%). The bronchoalveolar lavage culture results showed that the most commonly isolated microorganisms were H. influenzae non-type b (7.8%) followed by M. catarrhalis (7.3%). Mucus obstruction and secretion (33.0%) constituted the most common bronchoscopic findings, while the flexible bronchoscopy examination was normal in 27% of patients. No serious complications occurred in any patient during or after the procedure. The results of this study demonstrated that the most common indication for flexible bronchoscopy was recurrent lower respiratory tract infection and the most common bronchoscopy finding was purulent secretion with mucus obstruction. Flexible bronchoscopy is an important diagnostic and treatment tool for patients with recurrent respiratory symptoms. It is a highly valuable method as it enables direct visualization of the airways and facilitates the collection of bronchoalveolar lavage samples.

Comparing semi-recumbent lateral position vs semi-recumbent position in preventing VAP and ARDS in traumatic brain injury patients requiring mechanical ventilation

Background and aimsVentilator-associated pneumonia is a common nosocomial infection in the intensive care unit among traumatic brain injury patients, resulting in increased morbidity and mortality. We have assessed the effectiveness of semi-recumbent lateral positioning in comparison with semi‐recumbent positioning to prevent ventilator-associated pneumonia and acute respiratory distress syndrome in traumatic brain injury patients requiring mechanical ventilation. MethodsIn a single-blind prospective randomised clinical trial, 100 patients were recruited in the intensive care unit and randomly assigned to the control group (n = 50) and intervention group (n = 50). Patients in control group maintained semi-recumbent position with 30–45° head of bed elevation and intervention group maintained semi-recumbent lateral position with lateral turning ≥45° and head of bed elevation 30–45° every 4 h. Bronchoalveolar lavage for diagnosis of ventilator-associated pneumonia, Glasgow Coma Score, clinical pulmonary infection score, duration of mechanical ventilation, PaO2/FiO2 ratio and incidence of acute respiratory distress syndrome were investigated for 10 days. ResultsComparing semi-recumbent position with semi-recumbent lateral position, the latter showed significant decrease in ventilator-associated pneumonia with lower clinical pulmonary infection score at day 3 (6.5 ± 2.9; 1.8 ± 2.1; p < 0.001), day 7 (6.6 ± 2.6; 2.6 ± 2.3; p < 0.001) and day 10 (7.7 ± 2.9; 2.3 ± 2.3; p = 0.001) and decreased incidence of positive bronchoalveolar lavage cultures at day 3 (p = 0.02), day 7 (p < 0.001) and day 10 (p = 0.001). Duration of mechanical ventilation was significantly reduced at day 7 (p = 0.04) and day 10 (p < 0.001). The incidence of acute respiratory distress syndrome was not different. ConclusionSemi-recumbent lateral position results in significant less incidence of ventilator-associated pneumonia and reduced duration of mechanical ventilation. Trial registration numberICMR-NIMS CTRI/2019/01/016829.

Urolithin A exerts a protective effect on lipopolysaccharide-induced acute lung injury by regulating HMGB1-mediated MAPK and NF-κB signaling pathways.

Acute lung injury (ALI) is a severe inflammatory disorder that has a high morbidity and mortality rate. Urolithin A (UA) is reported to have anti-inflammatory and anti-oxidative effects in ALI. However, its molecular mechanisms in ALI remain to be explored. Mice and BEAS-2B cells were administrated with lipopolysaccharide (LPS) to mimic the ALI model in vivo and in vitro. Hematoxylin-eosin (HE) staining was used to detect the pathological injury of lung tissues. The levels of proinflammatory cytokines in bronchoalveolar lavage fluid (BALF) and culture supernatant and the levels of oxidative stress markers in lung tissues were measured using ELISA. DCFH-DA probe was used to assess the reactive oxygen species (ROS) level. TUNEL staining and flow cytometry were performed to determine cell apoptosis. The key targets and pathways were confirmed by immunohistochemistry (IHC) and western blot. UA suppressed the pathologic damage, wet/dry weight ratio, and total protein and inflammatory cells in BALF. UA decreased neutrophil infiltration and proinflammatory cytokines production. UA reduced the level of malondialdehyde (MDA) and increased the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in pulmonary tissues. UA also inhibited cell apoptosis in lung tissues by decreasing Bax expression and increasing Bcl-2 expression. In addition, UA suppressed LPS-induced inflammatory factor production, ROS level, and cell apoptosis in BEAS-2B. Importantly, UA decreased the expression of HMGB1 in LPS-treated mice and BEAS-2B cells. HMGB1 overexpression greatly abrogated the inhibition of UA on inflammation, ROS, and cell apoptosis in LPS-administrated BEAS-2B. Furthermore, UA treatment suppressed the phosphorylated levels of p38, JNK, ERK, and p65 in LPS-administrated mice and BEAS-2B cells. UA alleviated lung inflammation, oxidative stress, and apoptosis in ALI by targeting HMGB1 to inactivate the MAPK/NF-κB signaling, suggesting the potential of UA to treat ALI.

Absence of COVID-19 associated mucormycosis in a tertiary intensive care unit in the Netherlands

Mucormycosis is a severe complication in critically ill COVID-19 patients. Throughout the pandemic, a notable prevalence of mucormycosis has been observed in the Indian population, whereas lower occurrences have been reported in Europe. However, limited data exist regarding its prevalence in Europe, which is potentially underestimated due to the low sensitivity of bronchoalveolar lavage (BAL) cultures. We aimed to evaluate the prevalence of mucormycosis in a high-risk critically ill COVID-19 population in the Netherlands, and to evaluate the potential benefit of adding Mucor PCR to BAL as part of routine follow-up. In this study, we included 1035 critically ill COVID-19 patients admitted to either one of the two ICUs at AmsterdamUMC between March 2020 and May 2022; of these, 374 had undergone at least one bronchoscopy. Following the AmsterdamUMC protocols, bronchoscopies were conducted weekly until clinical improvement was achieved. We cultured BAL fluid for fungi and used PCR and galactomannan testing to detect Aspergillus spp. Additionally, we retrospectively performed qPCR targeting Mucorales DNA in the BAL of 89 deceased patients. All cultures were negative for Mucorales, whereas 42 (11%) cultures were positive for Aspergillus. Furthermore, qPCR targeting Mucorales was negative in all 89 deceased patients. This study showed that pulmonary mucormycosis was not present in critically ill COVID-19 patients in two tertiary care ICUs. These results indicate routine Mucorales qPCR screening is not clinically necessary in a high-standard-of-care tertiary ICU in a low-endemic area.

Microbiological diagnosis of pulmonary invasive aspergillosis in critically ill patients with severe SARS-CoV-2 pneumonia: a bronchoalveolar study

BackgroundDiagnosing COVID-19-associated pulmonary aspergillosis (CAPA) can be challenging since radiological and clinical criteria in the critically ill patient are nonspecific. Microbiological diagnostic support is therefore crucial. The aim of this study was to document the incidence of aspergillosis using bronchoalveolar lavage (BAL) as the diagnostic method and to determine the performance of the current mycological diagnostic tests most widely used for the diagnosis of CAPA, together with evaluation of the Asp lateral flow device (LFD).MethodsProspective cohort study conducted between March 2020 and June 2022. Inclusion criteria were critically ill patients admitted to the ICU with SARS-CoV-2 pneumonia requiring invasive mechanical ventilation. Diagnostic bronchoscopy and BAL were performed at the beginning of invasive mechanical ventilation. The sensitivity, specificity, positive and negative predictive value (PPV and NPV), positive and negative likelihood ratio (LR + and LR-) of BAL culture, direct examination with calcofluor white stain, ELISA (Platelia) and LFD (AspLFD) for detection of galactomannan (GM) were evaluated. Aspergillus-qPCR was applied when discrepancies between diagnostic tests arose.ResultsOf the 244 critically ill patients with SARS-CoV-2 pneumonia admitted to the ICU, the majority (n = 200, 82%) required invasive mechanical ventilation. Diagnostic bronchoscopic procedures were performed in 160 patients (80%), who were enrolled in this study. The incidence of CAPA was 18.7% (n = 30). LFD-GM demonstrated a sensitivity of 84%, specificity of 99%, PPV 94%, NPV 97%, LR(+) of 84, and LR(-) of 0.16. At GM-ELISA indices of ≥ 0.5 and ≥ 1.0, sensitivity was 92% and 79%, specificity was 95% and 99%, PPV 76% and 91%, NPV 99% and 96%, LR(+) 18 and 79, and LR(-) 0.08 and 0.21, respectively. The optimal cut-off index from the ROC curve was 0.48, with sensitivity of 95% and specificity of 95%.ConclusionsUsing a diagnostic strategy based on bronchoscopy and BAL, we documented a high incidence of pulmonary aspergillosis in patients with severe SARS-CoV-2 pneumonia. Asp-LFD showed moderate sensitivity and excellent specificity, with a high PPV, and could be used for rapid diagnosis of patients with suspected CAPA.

Minimally invasive autopsies for the investigation of pulmonary pathology of COVID-19—experiences of a longitudinal series of 92 patients

Minimally invasive autopsies (MIAs) allow the collection of tissue samples for diagnostic and research purposes in special situations, e.g., when there is a high risk of infection which is the case in the context of COVID-19 or restrictions due to legal or personal reasons. We performed MIA to analyze lung tissue from 92 COVID-19 patients (mean age 78 years; range 48–98; 35 women, 57 men), representing 44% of all patients who died from the disease between October 2020 and April 2021. An intercostal approach was used with removal of a 5-cm rib section followed by manual collection of four lung tissue samples (5–8 cm in size). Diffuse alveolar damage (DAD) was found in 89 (97%) patients at various stages. Exudative DAD (eDAD) predominated in 18 (20%) patients, proliferative DAD (pDAD) in 43 (47%) patients, and mixed DAD (mDAD) in 31 (34%) patients. There were no significant differences in the predominant DAD pattern between tissue samples from the same patient. Additional purulent components were present in 46 (50%) cases. Fungi were detected in 11 (12%) patients. The pDAD pattern was associated with longer hospital stay including intensive care unit (p=0.026 and p<0.001) and younger age (p=0.019). Positive bronchoalveolar lavage and blood cultures were observed more frequently in pDAD patterns (p<0.001; p=0.018). In contrast, there was no significant association between intravital positive microbiological results and superimposed bronchopneumonia or fungal infection at autopsy. Having demonstrated the characteristic lung changes in a large longitudinal autopsy series, we conclude that the presented MIA approach can be considered a reliable and safe method for performing post mortem lung diagnostics in COVID-19 and other high-risk situations. The lack of correlation between histological changes indicative of bacterial or fungal superinfection and microbiology could have clinical implications for disease and treatment surveillance.

Biofire pneumonia panel in lung donors: faster detection but limited pathogens.

Culture of bronchoalveolar lavage (BAL) specimens takes time to report. We tested whether a molecular diagnostic test could accelerate donor lung assessment and treatment. We compared BioFireFilm ArrayPneumonia Panel (BFPP) with standard of care (SOC) tests on lung allograft samples at three time points: (1) donor BAL at organ recovery, (2) donor bronchial tissue and airway swab at implantation, and (3) first recipient BAL following lung implantation. Primary outcomes were the difference in time to result (Wilcoxon signed-ranked tests) and the agreement in results between BFPP and SOC assays (Gwet's agreement coefficient). We enrolled 50 subjects. In donor lung BAL specimens, BFPP detected 52 infections (14 out of 26 pathogens in the panel). Viral and bacterial BFPP results were reported 2.4 h (interquartile range, IQR 2.0-6.4) following BAL versus 4.6 h (IQR 1.9-6.0, p = 0.625) for OPO BAL viral SOC results and 66 h (IQR 47-87, p < .0001) for OPO BAL bacterial SOC results. Although there was high overall agreement of results between BAL-BFPP versus OPO BAL-SOC tests (Gwet's AC p < .001 for all), the level of agreement differed among 26 pathogens designed in BFPP and differed by types of specimens. BFPP could not detect many infections identified by SOC assays. BFPP decreased time to detection of lung pathogens among donated lungs, but it cannot replace SOC tests due to the limited number of pathogens in the panel.

Vancomycin-Allergy and Linezolid-Resistance in Patient with Methicillin-Resistance Staphylococcus aureus and Multi-Drug Resistance Acinetobacter baumannii Infection

Background: Hospital Acquired Pneumonia (HAP) has been burdening the healthcare system, especially when bacteria such as Acinetobacter baumannii and methicillin-resistance Staphylococcus aureus (MRSA) are involved. They created a dilemma regarding the appropriate antibiotic therapy utilized against them, especially when the patient is allergic/intolerant to their drug of choice. Case: A 71-year-old man developed HAP while he was admitted for an ischaemic stroke. His bronchoalveolar lavage (BAL) culture showed MRSA and Acinetobacter baumannii infection with multiple drug resistance including one of the drugs for MRSA infection, linezolid. Amikacin and vancomycin were given, but he developed an allergy to vancomycin. Due to the difficulty in treating him, we opted to administer only amikacin. His clinical condition showed daily improvement. During the last day of hospitalization, his sputum culture showed only normal flora. He no longer needed oxygen therapy and there was no longer any indication for him to be hospitalized. Conclusion: Individuals with multiple comorbidities, recent antibiotic use within the past 90 days, and immune-deficient conditions are at a higher risk of developing infections, including the possibility of dual infections. In this case, we found that the patient was unable to tolerate first-line drugs for MRSA like linezolid and vancomycin, which makes it difficult to decide upon effective treatments.

Indications, Efficacy, and Complications of Pediatric Bronchoscopy: A Retrospective Study at a Tertiary Center.

Background Bronchoscopy is an essential procedure for evaluating, diagnosing, and treating pediatric respiratory diseases. In this study, we demonstrate the indications and contraindications of bronchoscopy done in a tertiary referral hospital, Al Qassimi Woman's and Children's Hospital (AQWCH) in Sharjah, United Arab Emirates (UAE), in order to achieve better service. This study aims to evaluate patients' characteristics, diagnostic and therapeutic indications, and complications of bronchoscopy. Material and method This retrospective chart review included children aged between one day and 13 years, admitted to AQWCH, who underwent bronchoscopy (rigid or flexible) procedures between January 2018 and December 2019. All patients were identified by using a computerized search of hospital discharge diagnosis, which was codified as "pediatric bronchoscopy, flexible, rigid, bronchoalveolar lavage". The main study outcome measure was to evaluate patients' characteristics, diagnostic or therapeutic indications, bronchoalveolar lavage (BAL) analysis, as well as complications of bronchoscopy at AQWCH. Results There were 72 pediatric bronchoscopies (rigid and flexible) performed in patients aged less than 13 years old; the reason for bronchoscopy procedure was diagnostic in 51% and both diagnostic and therapeutic in 49%. Cough was the most common symptom (n=53; 74%), and chest recession was the most common clinical finding (n=46; 64%). Foreign body aspiration was the main indication (n=23; 32%), followed by stridor (26%). Consolidation was the most common radiological finding. Foreign body was the common finding, seen in 25% of bronchoscopies, followed by tracheomalacia in 17%. The suspected diagnosis was confirmed in 89%, and management change was needed in 54% of patients. The main complication during the procedure was desaturation (26%), and cough was the main post-bronchoscopy complication (14%). BAL was done for 28 (39%) patients, in which BAL culture was positive in 75%.Rigid bronchoscopy was done when foreign body aspiration was suspected based on positive history in 70%, abnormal physical examination in 60%, and chest X-ray abnormalities in 39% of patients. Sensitivity and specificity for patient history, physical examination, and chest X-ray were 80% and 83%, 66% and 60%, and 40% and 66 %, respectively. Conclusion Bronchoscopy is an important tool for evaluating, diagnosing, and treating pediatric respiratory diseases. While it is a safe procedure, it still needs a careful selection of patients as it is invasive.

Healthcare providers consistently overestimate the diagnostic probability of ventilator-associated pneumonia.

To assess the accuracy of provider estimates of ventilator-associated pneumonia (VAP) diagnostic probability in various clinical scenarios. We conducted a clinical vignette-based survey of intensive care unit (ICU) physicians to evaluate provider estimates of VAP diagnostic probability before and after isolated cardinal VAP clinical changes and VAP diagnostic test results. Responses were used to calculate imputed diagnostic likelihood ratios (LRs), which were compared to evidence-based LRs. Michigan Medicine University Hospital, a tertiary-care center. This study included 133 ICU clinical faculty and house staff. Provider estimates of VAP diagnostic probability were consistently higher than evidence-based diagnostic probabilities. Similarly, imputed LRs from provider-estimated diagnostic probabilities were consistently higher than evidence-based LRs. These differences were most notable for positive bronchoalveolar lavage culture (provider-estimated LR 5.7 vs evidence-based LR 1.4; P < .01), chest radiograph with air bronchogram (provider-estimated LR 6.0 vs evidence-based LR 3.6; P < .01), and isolated purulent endotracheal secretions (provider-estimated LR 1.6 vs evidence-based LR 0.8; P < .01). Attending physicians and infectious disease physicians were more accurate in their LR estimates than trainees (P = .04) and non-ID physicians (P = .03). Physicians routinely overestimated the diagnostic probability of VAP as well as the positive LRs of isolated cardinal VAP clinical changes and VAP diagnostic test results. Diagnostic stewardship initiatives, including educational outreach and clinical decision support systems, may be useful adjuncts in minimizing VAP overdiagnosis and ICU antibiotic overuse.

Rapid Diagnosis of Disseminated Tuberculosis Using Cell-free DNA Sequencing in a Kidney Transplant Recipient.

Here, we report a case of smear-negative disseminated tuberculosis (TB) in a kidney transplant recipient diagnosed using plasma cell-free DNA (cfDNA). A 68-y-old woman presented with 2 mo of fevers and a 15-pound weight loss. Six years earlier, she received a living donor kidney transplant from her husband for adult polycystic kidney disease. She received standard induction with antithymocyte globulin and maintenance immunosuppression with tacrolimus, mycophenolate mofetil, and low-dose prednisone. Her posttransplant course was uncomplicated. She was born and lived in Massachusetts and had not traveled internationally in many years. She worked in finance until she retired a few years prior. She had no history of incarceration or homelessness. Her hobbies included volunteering at a local food bank. On presentation, she was febrile to 38.8 °C and diaphoretic but otherwise appeared well. Her laboratory values were notable for a leukocytosis of 16 000 K/µL and a urinalysis with >100 white blood cells per high power field. There was no growth in the urine or blood cultures. Her nasopharyngeal multiplex polymerase chain reaction (PCR) was negative for common respiratory viruses. She had negative test results for Epstein-Barr virus DNA, cytomegalovirus DNA, HIV 1/2 antigen/antibody, cryptococcal and Histoplasma antigens. Chest computed tomography showed innumerable 1- to 3-mm bilateral nodules (Figure 1A) and lytic lesions of the T6 and T7 vertebral bodies. Spine magnetic resonance imaging demonstrated enhancing lesions involving the entire T6 and T7 bodies (Figure 1B).FIGURE 1.: Abnormal imaging findings. A, Chest CT scan with diffuse bilateral pulmonary nodules in a miliary pattern. B, MRI of the thoracic spine with enhancing lesions of the T6 and T7 vertebral bodies. CT, computed tomography.Further workup included bronchoalveolar lavage with multiple negative studies: bacterial cultures, Pneumocystis direct fluorescent antibody, galactomannan antigen, acid-fast bacilli (AFB) and modified AFB smear, and Mycobacterium tuberculosis PCR. Transbronchial biopsy was nondiagnostic, with negative AFB and fungal stains. Mycobacterial blood and urine cultures were also obtained. A biopsy of her T7 vertebral body noted chronic inflammation and 1 nonnecrotizing granuloma. On hospital day (HD) 13, while she remained febrile and without a definitive diagnosis, we sent a quantitative cfDNA test (Karius, Inc, Redwood City, CA). On HD 15, the Karius cfDNA test returned positive for M tuberculosis. Subsequently, the mycobacterial blood, urine, and bronchoalveolar lavage cultures grew M tuberculosis on HD 17, 17, and 21, respectively. Bone cultures grew M tuberculosis at 34 d after biopsy after the patient had been discharged from the hospital. Cell-free DNA tests have become increasingly prevalent in recent years, including donor-derived cfDNA, which is routinely used to detect allograft rejection. The Karius cfDNA test uses metagenomic next-generation sequencing to specifically detect microbial nucleic acid from over a thousand clinically relevant species in plasma.1 This was the first case of TB diagnosed by plasma cfDNA sequencing in our institution. The turnaround time of 48 h is a promising characteristic of this test, especially when slow-growing pathogens are suspected. Had it been obtained earlier in the course, this test would have not only expedited diagnosis and treatment initiation but also eliminated the need for invasive diagnostics. Nevertheless, like other molecular tests, cfDNA sequencing does not provide antimicrobial susceptibilities to guide antimicrobial therapy and thus does not eliminate the need for cultures. In a recent meta-analysis, cfDNA sequencing showed excellent specificity but poor pooled sensitivity for the diagnosis of TB.2 The very low-risk epidemiologic history for TB and disease onset in the late posttransplant period were other interesting features of this case. Her pretransplant T spot TB was negative. We considered donor-derived TB, but this was deemed unlikely because her donor was her husband, who was healthy and had a negative TB screening. She had no known exposures to TB, and her exposure to higher-risk populations via volunteerism was her only epidemiologic risk factor.

758 Correlation between initial and diagnostic bronchoalveolar lavage isolates among patients with inhalation injury and pneumonia

Abstract Introduction Inhalation injury is associated with increased risk of pneumonia. Bronchoscopy with bronchoalveolar lavage (BAL) is commonly used to diagnose and grade inhalation injury while obtaining a microbiological sample. It has been shown that a quarter of patients with inhalation injury have a single bacteria isolated from initial BAL within 12-48 hours of injury. The clinical significance of this and role of antibiotics in this setting are unknown. We investigated the incidence that bacteria isolated during a pneumonia episode were previously isolated on surveillance BAL among patients with inhalation injury. Methods Among patients with inhalation injury admitted to a large ABA-verified burn center from 2009-2022, microbiological isolates from initial BAL and subsequent culture obtained during a pneumonia episode (BAL, sputum), were extracted from medical records. Abbreviated injury severity score (AIS) was used to grade inhalation injury. Hospital-acquired pneumonia (HAP) was defined using CDC PNU1 criteria, and ventilator-associated pneumonia (VAP) was defined using PNU2 criteria with BAL cutoff &amp;gt;10,000 colony forming units (CFU). Results Two-hundred forty-eight patients with inhalation injury who underwent bronchoscopy for airway inspection and surveillance BAL within 48 hours of injury were included in the analysis. Of the 111 who had a bacterial isolate from initial BAL, 23 (21%) subsequently developed HAP or VAP during the hospitalization. Median (IQR) days between bronchoscopy and pneumonia diagnosis was six (2-8.5). In three of the 11 VAP cases (27%), the organisms identified at pneumonia diagnosis matched the organisms identified on initial BAL. Antibiotic use on admission was not associated with re-culture of initial BAL organism during a subsequent pneumonia episode (p=0.071). Conclusions Among patients with inhalation injury and bacteria isolated on surveillance BAL, 21% developed pneumonia during their hospital stay, usually with different bacteria than those isolated at initial bronchoscopy. There was no association between empiric antibiotic use and incidence of initial BAL organisms re-cultured during subsequent pneumonia episode. Applicability of Research to Practice Findings suggest initial BAL isolates cannot guide empiric coverage of pneumonia for patients with inhalation injury. This remains an important area of future research.

Detection of cytomegalovirus in bronchoalveolar lavage fluid from immunocompromised patients with pneumonitis by viral culture and DNA quantification

PurposeTo compare the detection of human cytomegalovirus (HCMV) in bronchoalveolar lavage (BAL) fluid by viral culture and quantitative polymerase chain reaction (qPCR), and to establish a viral load threshold that can identify cases of HCMV replication indicative of pneumonitis. There is currently no universal viral load cut-off to differentiate between patients with and without pneumonitis, and the interpretation of qPCR results is challenging. Methods176 consecutive BAL samples from immunosuppressed hosts with signs and/or symptoms of respiratory infection were prospectively studied by viral culture and qPCR. ResultsConcordant results were obtained in 81.25% of the BAL samples. The rest were discordant, as only 34% of the qPCR-positive BAL samples were positive by culture. The median HCMV load was significantly higher in culture-positive than in culture-negative BAL samples (5038 vs 178 IU/mL). Using a cut-off value of 1258 IU/mL of HCMV in BAL, pneumonia was diagnosed with a sensitivity of 76%, a specificity of 100%, a VPP of 100% and VPN of 98%, and HCMV was isolated in 100% of the BAL cultures. ConclusionWe found that a qPCR-negative was a quick and reliable way of ruling out HCMV pneumonitis, but a positive result did not always indicate clinically significant replication in the lung. However, an HCMV load in BAL fluid of ≥ 1258 IU/mL was always associated with disease, whereas < 200 IU/mL rarely so.

A Fatal Case of Pseudomonas aeruginosa Community-Acquired Pneumonia in an Immunocompetent Patient: Clinical and Molecular Characterization and Literature Review

Rare cases of Pseudomonas aeruginosa community-acquired pneumonia (PA-CAP) were reported in non-immunocompromised patients. We describe a case of Pseudomonas aeruginosa (PA) necrotizing cavitary CAP with a fatal outcome in a 53-year-old man previously infected with SARS-CoV-2, who was admitted for dyspnea, fever, cough, hemoptysis, acute respiratory failure and a right upper lobe opacification. Six hours after admission, despite effective antibiotic therapy, he experienced multi-organ failure and died. Autopsy confirmed necrotizing pneumonia with alveolar hemorrhage. Blood and bronchoalveolar lavage cultures were positive for PA serotype O:9 belonging to ST1184. The strain shares the same virulence factor profile with reference genome PA01. With the aim to better investigate the clinical and molecular characteristics of PA-CAP, we considered the literature of the last 13 years concerning this topic. The prevalence of hospitalized PA-CAP is about 4% and has a mortality rate of 33–66%. Smoking, alcohol abuse and contaminated fluid exposure were the recognized risk factors; most cases presented the same symptoms described above and needed intensive care. Co-infection of PA-influenza A is described, which is possibly caused by influenza-inducing respiratory epithelial cell dysfunction: the same pathophysiological mechanism could be assumed with SARS-CoV-2 infection. Considering the high rate of fatal outcomes, additional studies are needed to identify sources of infections and new risk factors, along with genetic and immunological features. Current CAP guidelines should be revised in light of these results.

Evaluation of BioFire® FilmArray® Pneumonia Panel in Bronchoalveolar Lavage Samples From Immunocompromised Patients With Suspected Pneumonia.

Objectives Immunocompromised patients, specifically those with solid organ transplants or cancer on chemotherapy, are at particularly high risk of severe pneumonia and opportunistic infections. In select patients, bronchoalveolar lavage (BAL) is performed to provide high-quality samples for analysis. We compare BioFire® FilmArray® Pneumonia Panel (BioFire Diagnostics,Salt Lake City, Utah, United States), a multiplex polymerase chain reaction (PCR) assay, with standard of care diagnostics in BAL samples from immunocompromised patients to identify opportunities for this test to affect clinical decision making. Methods Patients hospitalized with pneumonia based on clinical and radiographic findings who underwent evaluation with bronchoscopybetween May 2019 to January 2020 were reviewed. Among those patients undergoing bronchoscopy, those who were immunocompromised were selected for inclusion in the study. BAL specimens submitted to the microbiology laboratory were chosen based onas part of the internal validation of the panel in comparison with sputum culture at our hospitals.We compared the outcomes of the multiplex PCR assay with traditional culture methods and evaluated the role of PCR assay in de-escalating antimicrobial therapy. Results Twenty-four patients were identified for testing with the multiplex PCR assay. Of the 24 patients, 16 were immunocompromised, all with solid or hematological malignancy or a history of organ transplant. Seventeen individual BAL samples from the 16 patients were reviewed. BAL culture results and the multiplex PCR assay were in agreement in 13 samples (76.5%). In four cases, the multiplex PCR assay identified a possible causative pathogen not detected by standard workup. The median time to de-escalation of antimicrobials was three days (interquartile range (IQR) 2-4) from the day of collection of the BAL samples. Conclusions Studies have established the additive role of multiplex PCR testing in addition to traditional diagnostic tools like sputum culture in diagnosing the etiology of pneumonia. Limited data exist specifically looking at immunocompromised patients, in whom a timely and accurate diagnosis is particularly important. There is a potential benefit for performing multiplex PCR assays as an additive diagnostic tool in BAL samples for these patients.

A retrospective study on parapneumonic effusion in 130 dogs with a clinical diagnosis of pneumonia.

To screen the occurrence of parapneumonic effusion in dogs. Medical records were searched for dogs with a presumptive diagnosis of bacterial pneumonia from 2017 to 2021 at the Liege university teaching hospital. Bacterial pneumonia was presumptively diagnosed based on compatible clinical signs and findings; thoracic radiographs compatible with bacterial bronchopneumonia; and either increased serum C-reactive protein (CRP) levels, a positive bronchoalveolar lavage culture or a positive clinical evolution in response to antibiotic therapy. Patients diagnosed with parasitic or other non-bacterial inflammatory pneumonia or with pulmonary neoplasia were excluded. Signalment, clinical findings, and outcome were recorded. One hundred and thirty dogs were included in the study, of which 44 dogs (33.8%) developed a parapneumonic effusion. Four of these dogs (4/44; 9%) had thoracocentesis performed, displaying a modified transudate (2) or septic exudate (2). Although parapneumonic effusion in dogs with a presumptive diagnosis of bacterial pneumonia appears to be rather common (33.8%), thoracocentesis or chest tube placement was rarely performed. Furthermore, the outcome of dogs with and without parapneumonic effusion appears to be similar.

A marmoset model for Mycobacterium avium complex pulmonary disease.

Mycobacterium avium complex, is the most common nontuberculous mycobacterial respiratory pathogen in humans. Disease mechanisms are poorly understood due to the absence of a reliable animal model for M. avium complex pulmonary disease. The objectives of this study were to assess the susceptibility, immunologic and histopathologic responses of the common marmoset (Callithrix jacchus) to M. avium complex pulmonary infection. 7 adult female marmosets underwent endobronchial inoculation with 108 colony-forming units of M. intracellulare and were monitored for 30 or 60 days. Chest radiograph was assessed at baseline (prior to infection) and at the time of sacrifice (30 days for 3 animals and 60 days for 4 animals), and bronchoalveolar lavage cytokines, histopathology and cultures of the bronchoalveolar lavage, lungs, liver and kidney were assessed at time of sacrifice. Serum cytokines were monitored at baseline and weekly for 30 days for all animals and at 60 days for those alive. Group differences in serum cytokine measurements between those that tested positive versus negative for the M. intracellulare infection were assessed using a series of linear mixed models. Five of seven animals (two at 30 days and three at 60 days of infection) had positive lung cultures for M. intracellulare. Extra-pulmonary cultures were positive in three animals. All animals appeared healthy throughout the study. All five animals with positive lung cultures had radiographic changes consistent with pneumonitis. At 30 days, those with M. intracellulare lung infection showed granulomatous inflammation, while at 60 days there were fewer inflammatory changes but bronchiectasis was noted. The cytokine response in the bronchoalveolar lavage fluid was uniformly greater in the animals with positive M. intracellulare cultures than those without a productive infection, with greater levels at 30-days compared to 60-days. Similarly, serum cytokines were more elevated in the animals that had positive M. intracellulare cultures compared to those without a productive infection, peaking 14-21 days after inoculation. Endobronchial instillation of M. intracellulare resulted in pulmonary mycobacterial infection in marmosets with a differential immune response, radiographic and histopathologic abnormalities, and an indolent course consistent with M. avium complex lung infection in humans.

Pathogenic bacteria in bronchoalveolar lavage cultures and pediatric laryngotracheal reconstruction outcomes.

The primary objective was to determine if treating pathogenic bacteria in bronchoalveolar lavage (BAL) cultures improves outcomes after pediatric double stage laryngotracheal reconstruction (dsLTR). Case series with chart review. Tertiary children's hospital. All children (<18 years) obtaining flexible bronchoscopy with BAL cultures before dsLTR between 2016 and 2022 were included. Cultures identified abnormal bacterial growth or normal respiratory flora. Thirty-day postoperative surgical site or lung infections were captured and tracheostomy decannulation rates were obtained for children with at least 12 months of follow-up. Twenty-seven children obtained presurgical BAL cultures before dsLTR. Median age at reconstruction was 2.9 years (interquartile range: 2.3-3.5) and 89% (24/27) had high grade subglottic stenosis. Positive cultures were obtained in 56% of children (N = 15) with Pseudomonas aeruginosa (40%, 6/15) and methicillin-resistant Staphylococcus aureus (33%, 5/15) the most frequent organisms. All children with positive cultures were treated based on culture and sensitivity data. Postoperative infections developed in 22% (6/27) of children with equal distribution of surgical site and respiratory infections among children with pathogenic bacteria and normal respiratory flora. At 12 months after surgery, the decannulation rate was no different between those treated and not treated for a presurgical positive BAL culture (47% vs. 58%, p = 0.70). Pathogenic bacteria are common in BAL cultures from tracheostomy-dependent children before dsLTR. Treatment keeps respiratory infections and decannulation rates similar to children with negative cultures, suggesting continued benefit of flexible bronchoscopy and BAL in preparation for these surgeries.

O03 Rapid Infection Diagnostics in Cirrhosis (RIDiC): a novel molecular-based approach to address the ever increasing challenge of antimicrobial resistant infections in decompensated cirrhosis and acute-on-chronic liver failure

Abstract Background Global prevalence of MDR infections in cirrhotic patients has risen to 34% and associates with worsening clinical trajectory and mortality (Fernandez J et al. 2019). A major unmet need in addressing the challenge of antimicrobial resistance (AMR) in cirrhosis is rapid pathogen diagnosis and antimicrobial resistance (AMR) (Patel VC et al. 2019). These can facilitate selection of more effective antibiotic therapy, reducing selection for MDR organisms. The Curetis Unyvero™ platform (CUp) employs multiplex PCR technology for pathogen and AMR gene detection from multiple bodily tissues and fluids requiring minimal pre- processing. The investigator-initiated pilot study aimed to assess the utility of this platform for hospitalized cirrhotic patients. Methods Ascitic fluid, bronchoalveolar lavage (BAL) and blood culture samples were obtained from hospitalized cirrhotic patients with acute decompensation (AD) or acute-on-chronic liver failure (ACLF), in whom there was clinical suspicion of infection. Samples were tested using the IAI (intra-abdominal infection) panel, HPN (hospital pneumonia) panel and BCU (blood culture) panel based on sample type available. Results were not shared with clinicians for decision-making. Data were compared with standard microbiology diagnostics. Results 31 samples from 21 patients were tested: ascites (25), BAL (4), blood culture (2). Time to positive culture result of all samples was reduced with CUp compared with standard microbiology (4.59 versus 73.5 h). CUp showed 100% specificity (12/12) and detected the same organism in 100% of cases (10/12). In 6 samples, CUp identified pathogens which were consistent with clinical evidence of spontaneous bacterial peritonitis and previous positive isolates which standard microbiological diagnostics failed to identify. AMR genes identified by the CUp correlated with AMR patterns reported by standard diagnostics in 100% (5/5) of cases. In 2 patients, broad-spectrum antibiotic therapy continued although the CUp supported infection resolution. Four patients in whom CUp screening was negative continued to receive antibiotics whilst awaiting negative standard cultures that arrived 72 h later. CUp did not identify an Aspergillus species in one BAL sample as this is not part of the BAL panel. Conclusions These preliminary data suggest CUp results are compatible with standard laboratory diagnostics. The CUp may be utilized for earlier infection diagnosis and improve the targeting and de-escalation of antimicrobial therapy in AD and ACLF. These are crucial components in enhancing antibiotic stewardship strategies and to reduce MDR infections (Figure 1). Further work is however required to evaluate cost implications, validation and impact on clinical outcomes and mortality in cirrhosis.