Community-acquired Pseudomonas aeruginosa bloodstream infection: a classification that should not falsely reassure the clinician

Clinical characteristics, risk factors, and outcomes of patients with polymicrobial Pseudomonas aeruginosa bloodstream infections

BACKGROUND

Previous studies on polymicrobial Pseudomonas aeruginosa bloodstream infections (Pa-BSIs) are dated, and it is necessary to reanalyze polymicrobial Pa-BSIs. The aim of this study was to investigate clinical characteristics and risk factors for polymicrobial Pa-BSI in comparison with monomicrobial Pa-BSI.

METHODS

A double-center retrospective observational study was performed between January 1, 2013 and June 30, 2022, in two tertiary hospitals. All patients with Pa-BSI were enrolled, and their clinical data were collected by reviewing electronic medical records.

RESULTS

A total of 278 patients with Pa-BSI were enrolled, including 77 patients (27.7%) with polymicrobial Pa-BSI. Compared with monomicrobial Pa-BSI, the main source of polymicrobial Pa-BSI was pneumonia (49.4% vs 31.3%, p < 0.01), whereas the main source of monomicrobial Pa-BSI was primary BSIs (21.9% vs 2.6%, p = 0.04). In multivariate analysis, a history of cerebrovascular accident (CVA) (adjusted odds ratio [OR], 3.62; 95% CI, 1.46-8.92) was independently associated with polymicrobial Pa-BSI. Primary BSI was associated with monomicrobial Pa-BSI (OR, 0.08; 95% CI, 0.02-0.38). Patients with polymicrobial Pa-BSI had a longer intensive care unit (ICU) length of stay after onset of BSI than those with monomicrobial Pa-BSI (2 [2, 16] vs 13 [3.75, 29], p = 0.02).

CONCLUSION

Patients with Pa-BSI and the presence of CVA need to be alert to the possibility of polymicrobial BSI occurrence. Prolonged ICU stay and pneumonia as a source of BSI warrant clinician attention for polymicrobial Pa-BSI, and primary BSIs are likely associated with monomicrobial BSIs.

Pseudomonas aeruginosa Community-Onset Bloodstream Infections: Characterization, Diagnostic Predictors, and Predictive Score Development-Results from the PRO-BAC Cohort

Community-onset bloodstream infections (CO-BSI) caused by gram-negative bacilli are common and associated with significant mortality; those caused by Pseudomonas aeruginosa are associated with worse prognosis and higher rates of inadequateempirical antibiotic treatment. The aims of this study were to describe the characteristics of patients with CO-BSI caused by P. aeruginosa, to identify predictors, and to develop a predictive score for P. aeruginosa CO-BSI. Materials/methods: PROBAC is a prospective cohort including patients >14 years with BSI from 26 Spanish hospitals between October 2016 and May 2017. Patients with monomicrobial P. aeruginosa CO-BSI and monomicrobial Enterobacterales CO-BSI were included. Variables of interest were collected. Independent predictors of Pseudomonas aeruginosa CO-BSI were identified by logistic regression and a prediction score was developed. Results: A total of 78patients with P. aeruginosa CO-BSI and 2572 with Enterobacterales CO-BSI were included. Patients with P. aeruginosa had a median age of 70 years (IQR 60−79), 68.8% were male, median Charlson score was 5 (IQR 3−7), and 30-daymortality was 18.5%. Multivariate analysis identified the following predictors of CO-BSI-PA [adjusted OR (95% CI)]: male gender [1.89 (1.14−3.12)], haematological malignancy [2.45 (1.20−4.99)], obstructive uropathy [2.86 (1.13−3.02)], source of infection other than urinary tract, biliary tract or intra-abdominal [6.69 (4.10−10.92)] and healthcare-associated BSI [1.85 (1.13−3.02)]. Anindex predictive of CO-BSI-PA was developed; scores ≥ 3.5 showed a negative predictive value of 89% and an area under the receiver operator curve (ROC) of 0.66. Conclusions: We did not find a good predictive score of P. aeruginosa CO-BSI due to its relatively low incidence in the overall population. Our model includes variables that are easy to collect in real clinical practice and could be useful to detect patients with very low risk of P. aeruginosa CO-BSI.

Comparison between hospital- and community-acquired septic shock in children: a single-center retrospective cohort study

BACKGROUND

We explored the differences in baseline characteristics, pathogens, complications, outcomes, and risk factors between children with hospital-acquired septic shock (HASS) and community-acquired septic shock (CASS) in the pediatric intensive care unit (PICU).

METHODS

This retrospective study enrolled children with septic shock at the PICU of Beijing Children's Hospital from January 1, 2016, to December 31, 2019. The patients were followed up until 28 days after shock or death and were divided into the HASS and CASS group. Logistic regression analysis was used to identify risk factors for mortality.

RESULTS

A total of 298 children were enrolled. Among them, 65.9% (n = 91) of HASS patients had hematologic/oncologic diseases, mainly with Gram-negative bacterial bloodstream infections (47.3%). Additionally, 67.7% (n = 207) of CASS patients had no obvious underlying disease, and most experienced Gram-positive bacterial infections (30.9%) of the respiratory or central nervous system. The 28-day mortality was 62.6% and 32.7% in the HASS and CASS groups, respectively (P < 0.001). Platelet [odds ratio (OR) = 0.996, 95% confidence interval (CI) = 0.992-1.000, P = 0.028], positive pathogen detection (OR = 3.557, 95% CI = 1.307-9.684, P = 0.013), and multiple organ dysfunction syndrome (OR = 10.953, 95% CI = 1.974-60.775, P = 0.006) were risk factors for 28-day mortality in HASS patients. Lactate (OR = 1.104, 95% CI = 1.022-1.192, P = 0.012) and mechanical ventilation (OR = 8.114, 95% CI = 1.806-36.465, P = 0.006) were risk factors for 28-day mortality in patients with CASS.

CONCLUSIONS

The underlying diseases, pathogens, complications, prognosis, and mortality rates varied widely between the HASS and CASS groups. The predictors of 28-day mortality were different between HASS and CASS pediatric patients with septic shock.

Bloodstream infections in critically ill patients: an expert statement

Bloodstream infection (BSI) is defined by positive blood cultures in a patient with systemic signs of infection and may be either secondary to a documented source or primary—that is, without identified origin. Community-acquired BSIs in immunocompetent adults usually involve drug-susceptible bacteria, while healthcare-associated BSIs are frequently due to multidrug-resistant (MDR) strains. Early adequate antimicrobial therapy is a key to improve patient outcomes, especially in those with criteria for sepsis or septic shock, and should be based on guidelines and direct examination of available samples. Local epidemiology, suspected source, immune status, previous antimicrobial exposure, and documented colonization with MDR bacteria must be considered for the choice of first-line antimicrobials in healthcare-associated and hospital-acquired BSIs. Early genotypic or phenotypic tests are now available for bacterial identification and early detection of resistance mechanisms and may help, though their clinical impact warrants further investigations. Initial antimicrobial dosing should take into account the pharmacokinetic alterations commonly observed in ICU patients, with a loading dose in case of sepsis or septic shock. Initial antimicrobial combination attempting to increase the antimicrobial spectrum should be discussed when MDR bacteria are suspected and/or in the most severely ill patients. Source identification and control should be performed as soon as the hemodynamic status is stabilized. De-escalation from a broad-spectrum to a narrow-spectrum antimicrobial may reduce antibiotic selection pressure without negative impact on mortality. The duration of therapy is usually 5–8 days though longer durations may be discussed depending on the underlying illness and the source of infection. This narrative review covers the epidemiology, diagnostic workflow and therapeutic aspects of BSI in ICU patients and proposed up-to-date expert statements.

Rates, predictors and mortality of community-onset bloodstream infections due to Pseudomonas aeruginosa: systematic review and meta-analysis

BACKGROUND

Pseudomonas aeruginosa is mostly a nosocomial pathogen affecting predisposed patients. However, community-onset bloodstream infections (CO-BSI) caused by this organism are not exceptional.

OBJECTIVES

To assess the predisposing factors for CO-BSI due to P. aeruginosa (CO-BSI-PA) and the impact in mortality of inappropriate empirical antimicrobial therapy.

DATA SOURCE

A systematic literature search was performed in the Medline, Embase, Cochrane Library, Scopus and Web of Science databases. Study eligibility criteria and participants: Articles published between 1 January 2002 and 31 January 2018 reporting at least of 20 adult patients with CO-BSI due to P. aeruginosa were considered.

INTERVENTION

Empiric antimicrobial therapy for CO-BSI-PA.

METHODS

A systematic review and a meta-analysis were conducted for risk factors and to evaluate if inappropriate empiric antimicrobial therapy increased mortality in CO-BSI-PA using a Mantel-Haenszel effects model.

RESULTS

Twelve studies assessing data of 1120 patients were included in the systematic review. Solid tumour (33.1%), haematologic malignancy (26.4%), neutropenia (31.7%) and previous antibiotic use (44.8%) were the most prevalent predisposing factors. Septic shock was present in 42.3% of cases, and 30-day crude mortality was 33.8%. Mortality in meta-analysis (four studies) was associated with septic shock at presentation (odds ratio, 22.31; 95% confidence interval, 3.52-141.35; p 0.001) and with inappropriate empiric antibiotic therapy (odds ratio, 1.83; 95% confidence interval, 1.12-2.98l p 0.02).

CONCLUSIONS

CO-BSI-PA mostly occurred in patients with predisposing factors and had a 30-day mortality comparable to hospital-acquired cases. Inappropriate empirical antibiotic therapy was associated with increased mortality. Appropriate identification of patients at risk for CO-BSI-PA is needed for empirical treatment decisions.