Potential of Multiplex Polymerase Chain Reaction Performed on Protected Telescope Catheter Samples for Early Adaptation of Antimicrobial Therapy in ARDS Patients

Epidemiology and prediction of non-targeted bacteria by the filmarray pneumonia plus panel in culture-positive ventilator-associated pneumonia: a retrospective multicentre analysis

BACKGROUND

Ventilator-associated pneumonia (VAP) is a prevalent nosocomial infection in intensive care units (ICUs) with significant impacts on patient outcomes and healthcare costs. Multiplex PCR could allow for personalized empirical treatment of VAP and optimize antibiotic therapy.

METHODS

This multicenter retrospective study analyzed culture-positive VAP cases from January 2016 to March 2021 across 12 ICUs in France. The prevalence of non-targeted bacteria was evaluated according to the bacterial species included in the BioFire® FilmArray® Pneumonia Panel (FAPPP), and associated risk factors were identified. A non-targeted bacteria was defined as a bacterial species isolated during VAP, not included in the FilmArray panel, but considered by the clinician in the final antibiotic therapy.

RESULTS

Among 332 patients with 385 culture-positive VAP episodes, non-targeted pathogens were observed in 23% of cases (87/385) and represented 21% (110/534) of isolated bacteria (After excluding bacteria with low pathogenicity, the rate of VAP with a non-targeted bacterium was 21%). The most common non-targeted bacteria identified were Stenotrophomonas maltophilia (22%), Citrobacter koseri, and Hafnia alvei. Gram stain results poorly correlated with definitive cultures (42% of concordance). The proportion of culture-positive VAP with non-targeted bacteria varied significantly between ICUs, ranging from 12 to 37%, (p = 0.013). Polymicrobial culture-positive VAP had a twofold higher risk of non-targeted bacteria (47% vs. 25%, p < 0.001). In the multivariate analysis, in-ICU antibiotic exposure was associated with a twofold increased risk of non-targeted bacteria (25.3% vs. 12.9%, p = 0.042), and age over 70 years was associated with a threefold increased risk (p = 0.027). Among the 48 culture-positive VAP cases with ineffective empiric treatment, Pseudomonas aeruginosa (22%), Stenotrophomonas maltophilia (14%), and Enterobacter cloacae complex (8%) were the most frequent bacteria. Additionally, 67% of the culture-positive VAP cases with ineffective empirical antibiotic therapy involved targeted bacteria, of which 59% could have received effective empirical antibiotic therapy if panel results had been available, according to bacterial species identification and current guidelines.

CONCLUSIONS

A significant rate of culture-positive VAP cases with non-targeted bacteria was observed in this study, raising concerns about the interpretation of FAPPP results. Only positive FAPPP results may assist clinicians in the early personalization of antibiotic therapy for VAP.

Prevalence and predictors of confirmed infection in patients receiving empiric antimicrobials in the intensive care unit: a retrospective cohort study

BACKGROUND

Infection diagnosis in Intensive Care Units (ICUs) is a challenge given the spectrum of conditions that present with systemic inflammation, the illness severity and the delay and imprecision of existing diagnostic methods. We hence sought to analyze the prevalence and predictors of confirmed infection after empirical antimicrobials during ICU stay.

METHODS

retrospective cohort of prospectively collected ICU data in an academic tertiary hospital in São Paulo, Brazil. We included all adult patients given a new empirical antimicrobial during their ICU stay. We excluded patients using prophylactic or microbiologically guided antimicrobials. Primary outcome was infection status, defined as confirmed, probable, possible, or discarded. In a multivariable analysis, we explored variables associated with confirmed infection.

RESULTS

After screening 1721 patients admitted to the ICU from November 2017 to November 2022, we identified 398 new antimicrobial prescriptions in 341 patients. After exclusions, 243 antimicrobial prescriptions for 206 patients were included. Infection was classified as confirmed in 61 (25.1%) prescriptions, probable in 39 (16.0%), possible in 103 (42.4%), and discarded in 40 (16.5%). The only factor associated with infection was deltaSOFA (OR = 1.18, 95% CI 1.02 to 1.36, p = 0.022).

CONCLUSION

Suspected infection in the ICU is frequently not confirmed. Clinicians should be aware of the need to avoid premature closure and revise diagnosis after microbiological results. Development and implementation of new tools for faster infection diagnosis and guiding of antimicrobial prescription should be a research priority.

Performance and impact of rapid multiplex PCR on diagnosis and treatment of ventilated hospital-acquired pneumonia in patients with extended-spectrum β-lactamase-producing Enterobacterales rectal carriage

BACKGROUND

Antimicrobial stewardship (AMS) for ventilator-associated pneumonia (VAP) or ventilated hospital-acquired pneumonia (vHAP) in extended-spectrum β-lactamase-producing Enterobacterales (ESBL-E) carriers is challenging. BioFire® FilmArray® Pneumonia plus Panel (mPCR) can detect bacteria and antibiotic resistance genes, including blaCTX-M, the most common ESBL-encoding gene.

METHODS

This monocentric, prospective study was conducted on a group of ESBL-E carriers from March 2020 to August 2022. The primary objective was to evaluate the concordance between the results of mPCR and conventional culture performed on respiratory samples of ESBL-E carriers to investigate suspected VAP/vHAP. The secondary objective was to appraise the impact of performing or not mPCR on initial antibiotic therapy adequacy in ESBL-E carriers with confirmed VAP/vHAP.

RESULTS

Over the study period, 294 patients with ESBL-E carriage were admitted to the ICU, of who 168 (57%) were mechanically ventilated. (i) Diagnostic performance of mPCR was evaluated in suspected 41 episodes of VAP/vHAP: blaCTX-M gene was detected in 15/41 (37%) episodes, where 9/15 (60%) were confirmed ESBL-E-induced pneumonia. The culture and blaCTX-M were concordant in 35/41 (85%) episodes, and in all episodes where blaCTX-M was negative (n = 26), the culture never detected ESBL-E. (ii) The impact of mPCR on initial antibiotic therapy adequacy was assessed in 95 episodes of confirmed VAP/vHAP (22 episodes were tested with mPCR and 73 without); 47 (49%) episodes were ESBL-E-induced, and 24 (25%) were carbapenem-resistant bacteria-induced. The use of mPCR was significantly associated with higher prescription of adequate empirical antibiotic therapy in the multivariable logistic regression (adjusted odds ratio (aOR) (95% CI) of 7.5 (2.1-35.9), p = 0.004), propensity-weighting (aOR of 5.9 (1.6-22.1), p = 0.008), and matching-cohort models (aOR of 5.8 (1.5-22.1), p = 0.01).

CONCLUSION

mPCR blaCTX-M showed an excellent diagnostic value to rule out the diagnosis of ESBL-E related pneumonia in ESBL-E carriers with suspected VAP/vHAP. In addition, in patients with confirmed VAP/vHAP, a mPCR-based antibiotic therapy was associated with an increased prescription of adequate empirical antibiotic therapy. Performing mPCR on respiratory samples seems to be a promising tool in ESBL-E carriers with suspected vHAP/VAP. However, if mPCR is used in very low pre-test clinical probability of pneumonia, due to the high sensitivity and the rate of overdiagnosed pneumonia, the risk of overconsumption of carbapenem may prevail. Further studies are warranted.

Performance evaluation of a PCR panel (FilmArray® Pneumonia Plus) for detection of respiratory bacterial pathogens in respiratory specimens: A systematic review and meta-analysis

BACKGROUND

Accuracy and timing of antibiotic therapy remain a challenge for lower respiratory tract infections. New molecular techniques using Multiplex Polymerase Chain Reaction, including the FilmArray® Pneumonia Plus Panel [FAPP], have been developed to address this. The aim of this study is to evaluate the FAPP diagnostic performance for the detection of the 15 typical bacteria of the panel from respiratory samples in a meta-analysis from a systematic review.

METHODS

We searched PubMed and EMBASE from January 1, 2010, to December 31, 2022, and selected any study on the FAPP diagnostic performance on respiratory samples compared to the reference standard, bacterial culture. The main outcome was the overall diagnostic accuracy with sensitivity and specificity. We calculated the log Diagnostic Odds Ratio and analyzed performance for separate bacteria, antimicrobial resistance genes, and according to the sample type. We also reported the FAPP turnaround time and the out-of-panel bacteria number and species. This study is registered with PROSPERO (CRD42021226280).

RESULTS

From 10 317 records, we identified 30 studies including 8 968 samples. Twenty-one were related to intensive care. The overall sensitivity and specificity were 94% [95% Confidence Interval (CI) 91-95] and 98% [95%CI 97-98], respectively. The log Diagnostic Odds Ratio was 6.35 [95%CI 6.05-6.65]. 9.3% [95%CI 9.2-9.5] of bacteria detected in culture were not included in the FAPP panel.

CONCLUSION

This systematic review reporting the FAPP evaluation revealed a high accuracy. This test may represent an adjunct tool for pulmonary bacterial infection diagnostic and antimicrobial stewardship. Further evidence is needed to assess the impact on clinical outcome.

Antibiotic stewardship in the ICU: time to shift into overdrive

Antibiotic resistance is a major health problem and will be probably one of the leading causes of deaths in the coming years. One of the most effective ways to fight against resistance is to decrease antibiotic consumption. Intensive care units (ICUs) are places where antibiotics are widely prescribed, and where multidrug-resistant pathogens are frequently encountered. However, ICU physicians may have opportunities to decrease antibiotics consumption and to apply antimicrobial stewardship programs. The main measures that may be implemented include refraining from immediate prescription of antibiotics when infection is suspected (except in patients with shock, where immediate administration of antibiotics is essential); limiting empiric broad-spectrum antibiotics (including anti-MRSA antibiotics) in patients without risk factors for multidrug-resistant pathogens; switching to monotherapy instead of combination therapy and narrowing spectrum when culture and susceptibility tests results are available; limiting the use of carbapenems to extended-spectrum beta-lactamase-producing Enterobacteriaceae, and new beta-lactams to difficult-to-treat pathogen (when these news beta-lactams are the only available option); and shortening the duration of antimicrobial treatment, the use of procalcitonin being one tool to attain this goal. Antimicrobial stewardship programs should combine these measures rather than applying a single one. ICUs and ICU physicians should be at the frontline for developing antimicrobial stewardship programs.