Predictive model for bacterial co-infection in patients hospitalized for COVID-19: a multicenter observational cohort study.

OBJECTIVE: The aim of our study was to build a predictive model able to stratify the risk of bacterial co-infection at hospitalization in patients with COVID-19. METHODS: Multicenter observational study of adult patients hospitalized from February to December 2020 with confirmed COVID-19 diagnosis. Endpoint was microbiologically documented bacterial co-infection diagnosed within 72 h from hospitalization. The cohort was randomly split into derivation and validation cohort. To investigate risk factors for co-infection univariable and multivariable logistic regression analyses were performed. Predictive risk score was obtained assigning a point value corresponding to ß-coefficients to the variables in the multivariable model. ROC analysis in the validation cohort was used to estimate prediction accuracy. RESULTS: Overall, 1733 patients were analyzed: 61.4% males, median age 69 years (IQR 57-80), median Charlson 3 (IQR 2-6). Co-infection was diagnosed in 110 (6.3%) patients. Empirical antibiotics were started in 64.2 and 59.5% of patients with and without co-infection (p = 0.35). At multivariable analysis in the derivation cohort: WBC ≥ 7.7/mm3, PCT ≥ 0.2 ng/mL, and Charlson index ≥ 5 were risk factors for bacterial co-infection. A point was assigned to each variable obtaining a predictive score ranging from 0 to 5. In the validation cohort, ROC analysis showed AUC of 0.83 (95%CI 0.75-0.90). The optimal cut-point was ≥2 with sensitivity 70.0%, specificity 75.9%, positive predictive value 16.0% and negative predictive value 97.5%. According to individual risk score, patients were classified at low (point 0), intermediate (point 1), and high risk (point ≥ 2). CURB-65 ≥ 2 was further proposed to identify patients at intermediate risk who would benefit from early antibiotic coverage. CONCLUSIONS: Our score may be useful in stratifying bacterial co-infection risk in COVID-19 hospitalized patients, optimizing diagnostic testing and antibiotic use.

Tolerability of pulsed high-dose L-AmB as pre-emptive therapy in patients at high risk for intra-abdominal candidiasis: A phase 2 study (LAMBDA study).

BACKGROUND: Intra-abdominal candidiasis (IAC) has a high mortality rate. However, the correct management of a critically ill patient with suspected IAC remains unclear. The aim of this study was to evaluate the safety of pulsed high-dose liposomal amphotericin B (L-AmB) in patients with suspected IAC managed with a beta-D-glucan (BDG)-guided strategy. METHODS: This phase 2 prospective study enrolled adult patients with intra-abdominal sepsis following surgery. Patients received a single dose of L-AmB 5 mg/kg on day 1. On day 3, L-AmB was discontinued in patients with a negative basal BDG result, and continued (3 mg/kg/daily) in patients with a positive basal BDG result or microbiologically confirmed IAC. The primary endpoint was the occurrence of adverse events, defined using the Common Toxicity Criteria classification. RESULTS: In total, 40 patients were enrolled from January 2019 to August 2022. Fifteen (37.5%) patients were male, and the median age was 65 [interquartile range (IQR) 49-76] years. Thirty-one (77.5%) patients underwent urgent surgery, and the principal indication was secondary/tertiary peritonitis (n=22, 55%); half of the patients had undergone a previous surgical operation within the preceding 30 days. Five (12.5%) patients met the criteria for septic shock at enrolment. The median APACHE II score on admission to the intensive care unit was 12 (IQR 10-15). IAC was excluded in 33 (85%) patients, but IAC was probable and proven in five (12.5%) and two (5%) patients, respectively. The single dose of L-AmB 5 mg/kg was well tolerated in all patients, and no early or late severe adverse events related to the drug were reported. L-AmB was discontinued in 65% of patients following a negative basal BDG result. The all-cause 30-day mortality rate was 15%, and no deaths were related to L-AmB administration or uncontrolled IAC. The mortality rates for patients with and without proven IAC were 0% and 15.8%, respectively (P=0.99). CONCLUSIONS: The rate of proven IAC among critically ill high-risk patients was low (5%). A single dose of L-AmB 5 mg/kg, with prompt withdrawal in the case of a basal negative BDG result, seems to be a safe and effective approach in this population.

The lower respiratory tract microbiome of critically ill patients with COVID-19.

COVID-19 infection may predispose to secondary bacterial infection which is associated with poor clinical outcome especially among critically ill patients. We aimed to characterize the lower respiratory tract bacterial microbiome of COVID-19 critically ill patients in comparison to COVID-19-negative patients. We performed a 16S rRNA profiling on bronchoalveolar lavage (BAL) samples collected between April and May 2020 from 24 COVID-19 critically ill subjects and 24 patients with non-COVID-19 pneumonia. Lung microbiome of critically ill patients with COVID-19 was characterized by a different bacterial diversity (PERMANOVA on weighted and unweighted UniFrac Pr(> F) = 0.001) compared to COVID-19-negative patients with pneumonia. Pseudomonas alcaligenes, Clostridium hiranonis, Acinetobacter schindleri, Sphingobacterium spp., Acinetobacter spp. and Enterobacteriaceae, characterized lung microbiome of COVID-19 critically ill patients (LDA score > 2), while COVID-19-negative patients showed a higher abundance of lung commensal bacteria (Haemophilus influenzae, Veillonella dispar, Granulicatella spp., Porphyromonas spp., and Streptococcus spp.). The incidence rate (IR) of infections during COVID-19 pandemic showed a significant increase of carbapenem-resistant Acinetobacter baumannii (CR-Ab) infection. In conclusion, SARS-CoV-2 infection and antibiotic pressure may predispose critically ill patients to bacterial superinfection due to opportunistic multidrug resistant pathogens.