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Huynh D, Tung N, Dam Q, Tran T, Hulten KG, Harrison CJ, Kaplan SL, Nguyen A, Do TH, Setty A, Le J. Amoxicillin and penicillin G dosing in pediatric community-acquired pneumococcal pneumonia in the era of conjugate pneumococcal vaccines. Pharmacotherapy 2022. [PMID: 36571459 DOI: 10.1002/phar.2756] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 11/11/2022] [Accepted: 11/13/2022] [Indexed: 12/27/2022]
Abstract
BACKGROUND Parenteral penicillin G (PENG) and oral amoxicillin (AMOX) are recommended as treatment for pediatric community-acquired pneumonia (CAP). With recent epidemiologic penicillin susceptibility data for Streptococcus pneumoniae, the most common etiology of CAP, the objective of this study was to evaluate optimal dosing regimens of PENG and AMOX based on population pharmacokinetics linked to current susceptibility data. METHODS Using NONMEM v7.3, Monte Carlo simulations (N = 10,000) were conducted for AMOX 15 mg/kg/dose PO every 8 h (standard-dose), AMOX 45 mg/kg/dose PO every 12 h (high-dose), and PENG 62,500 units/kg/day IV every 6 h using six virtual subjects with ages spanning 3 months to 15 years old. The probability of target attainment (PTA) was determined for both serum and epithelial lining fluid (ELF) to achieve free drug concentrations above the minimum inhibitory concentration (%fT>MIC) across the population of pneumococci for 30%-50% of the dosing interval. RESULTS In 2018, all 21 (100%) pneumococcal isolates were susceptible to both PENG and AMOX based on Clinical and Laboratory Standards Institute (CLSI; MIC at 2 mg/L) breakpoints, and 15 of 21 (71%) were susceptible based on EUCAST (MIC at 0.5 mg/L) breakpoints. As compared to CLSI, EUCAST breakpoints consistently achieved higher PTA for all antibiotic regimens. At 50% fT>MIC in the serum at the susceptible MICs, standard-dose AMOX achieved >4% PTA (CLSI) and >86% PTA (EUCAST); high-dose AMOX achieved >73% PTA (CLSI) and >99% PTA (EUCAST); and PENG achieved 0% PTA (using CLSI) and 100% PTA (using EUCAST). Standard-dose AMOX, high-dose AMOX, and PENG achieved >71%, >93%, and 100% PTA, respectively, in the serum at 30%-50% fT>MIC when each patient was stochastically linked to an MIC based on the frequency distribution of national susceptibility data. The PTA was consistently lower in ELF as compared with serum for all regimens. CONCLUSION Based on the recent rates of resistance, antibiotic doses evaluated provide appropriate exposure for pediatric CAP based on the serum and ELF data associated with predicted clinical and microbiologic success for pneumococcus. High-dose AMOX may still be required to treat pediatric CAP, especially if using CLSI breakpoints. Ongoing surveillance for resistance is essential.
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Affiliation(s)
- Dustin Huynh
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego, San Diego, California, USA
| | - Norint Tung
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego, San Diego, California, USA
| | - Quang Dam
- Miller Children's and Women's Hospital of Long Beach, Long Beach, California, USA
| | - Tri Tran
- School of Medicine, University of California Riverside, Riverside, California, USA
| | - Kristina G Hulten
- Department of Pediatrics, Division of Infectious Diseases, Baylor College of Medicine, Houston, Texas, USA
| | - Christopher J Harrison
- School of Medicine, University of Missouri-Kansas City, Kansas City, Missouri, USA
- Children's Mercy Hospital, Kansas City, Missouri, USA
| | - Sheldon L Kaplan
- Department of Pediatrics, Division of Infectious Diseases, Baylor College of Medicine, Houston, Texas, USA
| | - Allison Nguyen
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego, San Diego, California, USA
| | - Tyler H Do
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego, San Diego, California, USA
| | - Amartya Setty
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego, San Diego, California, USA
| | - Jennifer Le
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego, San Diego, California, USA
- Miller Children's and Women's Hospital of Long Beach, Long Beach, California, USA
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Le J, Dam Q, Schweizer M, Thienphrapa W, Nizet V, Sakoulas G. Effects of vancomycin versus nafcillin in enhancing killing of methicillin-susceptible Staphylococcus aureus causing bacteremia by human cathelicidin LL-37. Eur J Clin Microbiol Infect Dis 2016; 35:1441-7. [PMID: 27234592 DOI: 10.1007/s10096-016-2682-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 05/13/2016] [Indexed: 02/06/2023]
Abstract
Recent studies have demonstrated that anti-staphylococcal beta-lactam antibiotics, like nafcillin, render methicillin-resistant Staphylococcus aureus (MRSA) more susceptible to killing by innate host defense peptides (HDPs), such as cathelicidin LL-37. We compared the effects of growth in 1/4 minimum inhibitory concentration (MIC) of nafcillin or vancomycin on the LL-37 killing of 92 methicillin-susceptible S. aureus (MSSA) isolates. For three randomly selected strains among these, we examined the effects of nafcillin, vancomycin, daptomycin, or linezolid on LL-37 killing and autolysis. Growth in the presence of subinhibitory nafcillin significantly enhanced LL-37 killing of MSSA compared to vancomycin and antibiotic-free controls. Nafcillin also reduced MSSA production of the golden staphylococcal pigment staphyloxanthin in 39 % of pigmented strains vs. 14 % for vancomycin. Among the antibiotics tested, only nafcillin resulted in significantly increased MSSA autolysis. These studies point to additional mechanisms of anti-staphylococcal activity of nafcillin beyond direct bactericidal activity, properties that vancomycin and other antibiotic classes do not exhibit. The ability of nafcillin to enhance sensitivity to innate HDPs may contribute to its superior effectiveness against MSSA, as suggested by studies comparing clinical outcomes to vancomycin treatment.
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Affiliation(s)
- J Le
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, 9500 Gilman Drive, MC 0714, La Jolla, CA, 92093-0714, USA.
| | - Q Dam
- University of California San Diego School of Medicine, La Jolla, CA, USA
| | - M Schweizer
- Iowa City VA Health Care System, Iowa City, IA, USA
- University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - W Thienphrapa
- University of California San Diego School of Medicine, La Jolla, CA, USA
| | - V Nizet
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, 9500 Gilman Drive, MC 0714, La Jolla, CA, 92093-0714, USA
- University of California San Diego School of Medicine, La Jolla, CA, USA
| | - G Sakoulas
- University of California San Diego School of Medicine, La Jolla, CA, USA
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Lin L, Nonejuie P, Munguia J, Hollands A, Olson J, Dam Q, Kumaraswamy M, Rivera H, Corriden R, Rohde M, Hensler ME, Burkart MD, Pogliano J, Sakoulas G, Nizet V. Azithromycin Synergizes with Cationic Antimicrobial Peptides to Exert Bactericidal and Therapeutic Activity Against Highly Multidrug-Resistant Gram-Negative Bacterial Pathogens. EBioMedicine 2015; 2:690-8. [PMID: 26288841 PMCID: PMC4534682 DOI: 10.1016/j.ebiom.2015.05.021] [Citation(s) in RCA: 195] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 05/21/2015] [Accepted: 05/21/2015] [Indexed: 12/22/2022] Open
Abstract
Antibiotic resistance poses an increasingly grave threat to the public health. Of pressing concern, rapid spread of carbapenem-resistance among multidrug-resistant (MDR) Gram-negative rods (GNR) is associated with few treatment options and high mortality rates. Current antibiotic susceptibility testing guiding patient management is performed in a standardized manner, identifying minimum inhibitory concentrations (MIC) in bacteriologic media, but ignoring host immune factors. Lacking activity in standard MIC testing, azithromycin (AZM), the most commonly prescribed antibiotic in the U.S., is never recommended for MDR GNR infection. Here we report a potent bactericidal action of AZM against MDR carbapenem-resistant isolates of Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumannii. This pharmaceutical activity is associated with enhanced AZM cell penetration in eukaryotic tissue culture media and striking multi-log-fold synergies with host cathelicidin antimicrobial peptide LL-37 or the last line antibiotic colistin. Finally, AZM monotherapy exerts clear therapeutic effects in murine models of MDR GNR infection. Our results suggest that AZM, currently ignored as a treatment option, could benefit patients with MDR GNR infections, especially in combination with colistin. Standard MIC testing conditions overlook a potent activity of azithromycin vs. multidrug-resistant Gram-negative bacteria. Colistin and endogenous host defense peptide LL-37 markedly potentiate azithromycin penetration into bacterial cells. Azithromycin reduced bacterial load and mortality in mouse models of multidrug-resistant Gram-negative infection.
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Affiliation(s)
- Leo Lin
- Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Poochit Nonejuie
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jason Munguia
- Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Andrew Hollands
- Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Joshua Olson
- Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Quang Dam
- Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Monika Kumaraswamy
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Heriberto Rivera
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla CA 92093, USA
| | - Ross Corriden
- Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Manfred Rohde
- Central Facility for Microscopy, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Mary E Hensler
- Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Michael D Burkart
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla CA 92093, USA
| | - Joe Pogliano
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - George Sakoulas
- Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Victor Nizet
- Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA ; Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093, USA ; Rady Children's Hospital, San Diego, CA 92123, USA
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