Persistent Methicillin-Susceptible Bacteremia Rapidly Cleared with Cefazolin and Ertapenem Combination Therapy in a Patient with COVID-19

Daptomycin Plus Oxacillin for Persistent Methicillin-Susceptible Staphylococcus aureus Bacteremia

BACKGROUND

The preferred antibiotic salvage regimen for persistent methicillin-susceptible Staphylococcus aureus bacteremia (MSSAB) is unclear. Ertapenem with cefazolin or an antistaphylococcal penicillin has been primarily described, but identifying alternative carbapenem-sparing options may support antibiotic stewardship efforts and decrease the risk of antibiotic-associated Clostridioides difficile infection.

OBJECTIVE

We sought to evaluate the effectiveness and safety of daptomycin plus oxacillin (D/O) for persistent MSSAB.

METHODS

This was a single-center, retrospective cohort of patients with persistent MSSAB who received D/O between January 1, 2014, and January 1, 2023. Adult patients were included if they had blood cultures positive for MSSA ≥72 hours and received D/O combination for ≥48 hours. Patients were excluded if they were pregnant, incarcerated, or received another antibiotic considered to have excellent activity against MSSA. The primary outcome was time to MSSA bacteremia clearance post-daptomycin initiation. Secondary outcomes included microbiological cure, hospital length of stay, 90-day all-cause mortality, MSSA bacteremia-related mortality, 90-day readmission for MSSAB, and incidence of antibiotic-associated adverse effects. Time to MSSAB clearance post-D/O initiation was plotted using Kaplan-Meier estimation.

RESULTS

Seven unique patient encounters were identified including 4 with endocarditis. Despite a median MSSA bacteremia duration of 7.8 days, median clearance was 2 days post-daptomycin initiation. All achieved microbiological cure, and no adverse effects were reported. Ninety-day all-cause mortality, MSSAB-related mortality, and 90-day readmission for MSSAB occurred in 28.6%, 14.3%, and 14.3% of patients, respectively.

CONCLUSIONS AND RELEVANCE

D/O was an effective, well-tolerated salvage regimen in this cohort and may represent a carbapenem-sparing option for persistent MSSAB.

Therapeutic Options for Adult Patients With Persistent Methicillin-Susceptible Staphylococcus aureus Bacteremia: A Narrative Review

OBJECTIVE

To compare the efficacy of antimicrobial therapies used in the management of persistent methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia.

DATA SOURCES

A literature search using the PubMed database (inception to December 2022) was conducted using the search terms "Staphylococcus aureus bacteremia," "methicillin-susceptible Staphylococcus aureus bacteremia," "persistent methicillin-susceptible Staphylococcus aureus bacteremia," and "refractory methicillin-susceptible Staphylococcus aureus bacteremia ." In addition, therapeutic agents which could be used as treatment for MSSA including "nafcillin," "oxacillin," "cefazolin," "ceftaroline," "gentamicin," "rifampin," and "daptomycin" were also combined with the aforementioned search terms to capture data using these agents.

STUDY SELECTION/DATA EXTRACTION

Clinical data were limited to those published in the English language. Articles and abstracts were considered for inclusion in addition to ongoing trials identified through ClinicalTrials.gov.

DATA SYNTHESIS

A total of 78 articles were reviewed including 17 in vitro or animal model studies and 39 studies including patient data. The remaining 22 articles included guidelines, review articles, and editorials. Recent data evaluating use of dual β-lactam regimens for persistent MSSA bacteremia were limited to 8 case reports or case series.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

At present, there is little guidance on how to best manage patients with persistent MSSA bacteremia. This narrative review collates the available data to assist clinicians in selecting the best possible antimicrobial regimen when facing this clinical conundrum.

CONCLUSIONS

Modification of antimicrobial therapy, in conjunction with source control and infectious diseases consultation, may all be necessary to sterilize blood cultures in patients with persistent MSSA bacteremia.

HPLC/UV approach method for the first simultaneous estimation of molnupiravir and ertapenem as a binary mixture in human plasma and dosage form as a regimen for COVID-19 treatments

COVID-19 is a serious virus that can have a lot of effects, one of which is a secondary bacterial infection that can be more life-threatening and even lethal than the initial viral infection. Hence a fast and sensitive HPLC/UV method was developed and validated for the first estimation of a binary mixture of molnupiravir (MOL) and ertapenem (ERT) as a co-administrated medicine for the management of COVID-19 in pharmaceutical dosage forms, and human plasma samples. The drug combination was separated within 5 min via RP-ODS column using isocratic elution with a mobile phase of 0.05 M phosphate buffer (pH 3.5): acetonitrile with a 76: 24% ratio v/v. The presented method provided a linear response ranging from 0.03 to 17.0 and 0.05-20 µg mL-1 with LOD values of 0.009 and 0.008 µg mL-1 for MOL and ERT respectively. The good separation and high sensitivity of the HPLC method provide the determination of the cited drugs in human plasma without matrix interference with a percent of recovery ranging from 94.97 ± 2.05 to 98.44 ± 1.92. Based on the results, this method could be utilized to monitor cited drugs in quality control and therapeutic laboratories.