Continuation Versus De-escalation of Broad-Spectrum Antibiotic Therapy in Critically Ill COVID-19 Patients

Background

Antibiotic de-escalation (ADE) is a stewardship initiative that aims to reduce exposure to antimicrobials, thus limiting their unwanted effect, including antimicrobial resistance. Our study aims to describe the impact of ADE compared with the continuation of therapy on the outcome of critically ill coronavirus disease 2019 (COVID-19) patients.

Material and Methods

A single-center retrospective study included critically ill COVID-19 adult patients admitted between January 1, 2019 and August 31, 2021, and started on broad-spectrum antibiotics. The primary outcome was intensive care unit (ICU) mortality. In addition, other clinical outcomes were evaluated, including ICU readmissions, length of stay, and superinfection.

Results

The study included 73 patients with a mean age of 61.0 ± 19.4, and ADE was performed in 10 (13.6%) of these. In the ADE group, 8/10 (80%) cultures were positive. ICU mortality was not statistically different between ADE and continuation of therapy groups (60 vs. 41.3%, respectively, P = 0.317). Superinfection occurred in 4 (5.4%) patients. Hospital mortality, length of stay, and ICU readmission rates did not differ significantly between groups.

Conclusion

De-escalation of broad-spectrum antibiotics in critically ill covid-19 patients was not associated with higher mortality. A larger cohort is needed to confirm these findings.

Supplementary Information

The online version contains supplementary material available at 10.1007/s44229-023-00027-0.

Simple method for the simultaneous analysis of pipecolic acid and lysine by high-performance liquid chromatography and its application to rumen liquor and plasma of ruminants

A high-performance liquid chromatography method for the simultaneous determination of pipecolic acid (Pip) and lysine (Lys), a precursor of Pip, in the rumen liquor and plasma of ruminant animals was established. Samples of rumen liquor and plasma were deproteinized with 50% acetonitrile and derivatized with a fluorescent agent 9-fluorenylmethyloxy carbonyl chloride (Fmoc-Cl). Chromatographic separation was achieved on a TSK gel ODS-80TM column using a reversed-phase gradient elution system. For the gradient elution, two mobile phases, A and B, were needed, both commonly consisted of: 5 mM L-proline, 2.5 mM cupric sulfate and 6.5 mM ammonium acetate. Mobile phase B additionally contains 50% (v/v) acetonitrile. The pH of both mobile phases was adjusted to 7.0. Derivatized Pip and Lys were detected on a fluorescent detector at excitation and emission wavelengths of 260 and 313 nm, respectively. The calibration curves were linear within the range 0 to 1 mM (r>0.999). The average recoveries for Pip and Lys were 95.9+/-1.8 and 93.2+/-2.5% in rumen liquor and 98.3+/-1.4 and 97.5+/-1.3% in plasma, respectively. The limits of detection for Pip and Lys were 0.6 and 0.7 microM in rumen liquor and 0.01 and 0.05 microM in plasma. The assay has acceptable precision, relative standard deviation (RSD) for reproducibility (within-day and day-to-day variation) were less than 5.2% for aqueous (5.0 microM Pip and Lys), MB9 (5.0 microM Pip and Lys), plasma (7.1 microM Pip and 85.6 microM Lys) and rumen liquor (28.4 microM Pip and 10.2 microM Lys) samples. The levels of Pip and Lys in faunated goats, determined from three animals over a period of two days sampling, were found to be 36.8+/-18.1 and 14.6+/-2.8 microM in rumen liquor, and 7.3+/-2.5 and 137.3+/-38.0 microM in plasma at 1 h after feeding. This is the first report on the normal levels of Pip in the rumen liquor and plasma of faunated goat.

Rapid determination of lysine in biological samples by isocratic liquid chromatography

A simple, rapid, and sensitive method was developed for detection and quantitation of lysine (Lys) in various biological samples by isocratic liquid chromatography (LC). Samples containing Lys and other amino acids were derivatized with 9-fluorenylmethyl chloroformate (FMOC-CI). The mobile phase used for isocratic elution was 50 mmol/L sodium acetate buffer (pH 4.20)-acetonitrile (43 + 57, v/v). Lys was detected with a UV detector at 265 nm. The derivatized Lys eluted from a LiChrospher 100 RP-18 (150 x 4.0 mm id) column at a retention time of 5.6 min. The limit of detection was 0.73 mumol/L (signal-to-noise [S/N] ratio, 3:1), and the limit of quantitation was 2.37 mumol/L (S/N ratio, 10:1). Lys recoveries from fortified biological samples were > 97.5%. Average Lys contents found in rumen fluid samples collected before the morning feeding and at 2.0, 4.0, and 6.0 h after feeding were 4.26, 3.34, 3.58, and 3.82 mumol/L, respectively. The hydrolysate of a sample of mixed rumen microorganisms collected before the morning feeding was determined to contain 1.372 mumol/mg microbial nitrogen in the form of Lys. The Lys concentrations of human plasma, goat plasma, human urine, and goat urine were 140.0, 102.0, 58.0, and 32.0 mumol/L, respectively.