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Ulloa ER, Sakoulas G. Azithromycin: An Underappreciated Quinolone-Sparing Oral Treatment for Pseudomonas aeruginosa Infections. Antibiotics (Basel) 2022; 11:515. [PMID: 35453266 PMCID: PMC9024921 DOI: 10.3390/antibiotics11040515] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 04/12/2022] [Accepted: 04/12/2022] [Indexed: 02/05/2023] Open
Abstract
Outpatient treatment of Pseudomonas aeruginosa infections is challenged by increasing rates of resistance to fluoroquinolones, the only class of antibiotics which offers an established oral route of administration against this organism. Azithromycin does not demonstrate activity against P. aeruginosa when evaluated under standard methods of susceptibility testing with bacteriologic media. However, growing evidence shows that azithromycin is very active against P. aeruginosa when using physiologic media that recapitulate the in vivo milieu and is supported by animal models of infection and various clinical settings, including cystic fibrosis. We present three cases of outpatient management of P. aeruginosa otolaryngological infections successfully treated with oral azithromycin, 500 mg daily ranging from 3-8 weeks, where use of fluoroquinolones was not possible due to either resistance or patient intolerance. We review the previous data supporting this clinical approach, in the hope that this will alert clinicians to this treatment option and to inspire a more thorough clinical trial evaluation of azithromycin in this environment of growing medical need.
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Affiliation(s)
- Erlinda R. Ulloa
- Department of Pediatrics, School of Medicine, University of California Irvine, Irvine, CA 92697, USA
- Division of Infectious Disease, Children’s Hospital of Orange County, Orange, CA 92868, USA
| | - George Sakoulas
- Sharp Rees-Stealy Medical Group, San Diego, CA 92123, USA;
- Collaborative to Halt Antibiotic-Resistant Microbes (CHARM), Department of Pediatrics, School of Medicine, University of California San Diego, La Jolla, CA 92093, 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: 201] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [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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Wu EC, Kowalski RP, Romanowski EG, Mah FS, Gordon YJ, Shanks RMQ. AzaSite® inhibits Staphylococcus aureus and coagulase-negative Staphylococcus biofilm formation in vitro. J Ocul Pharmacol Ther 2010; 26:557-62. [PMID: 21029017 DOI: 10.1089/jop.2010.0097] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
PURPOSE The aim of this study was to analyze the effect of azithromycin (AZM) 1% ophthalmic solution in DuraSite® (AzaSite®) on biofilm formation by Staphylococcus aureus and coagulase-negative staphylococci in vitro. METHODS Susceptible and resistant clinical strains (n = 8) of S. aureus and coagulase-negative staphylococci were challenged with serial dilutions of AzaSite® and its components: AZM, benzalkonium chloride (BAK), and the DuraSite drug delivery vehicle. After 20 h of incubation, bacterial growth was quantified using a spectrophotometer (A = 600 nm). Plates were stained with crystal violet and biofilm formation was quantified spectrophotometrically at A = 590 nm. RESULTS AzaSite® and AZM inhibited bacterial growth (P < 0.05) and biofilm formation (P < 0.05) in AZM-susceptible strains at all studied dilutions. AZM-resistant strains treated with AzaSite® exhibited a significant reduction in biofilm formation (P < 0.05) at subinhibitory concentrations (1.25%-5%). AZM had no effect on bacterial growth in resistant strains but conferred a small reduction in biofilm formation at concentrations from 1.25 to 10 mg/mL in most strains. DuraSite® inhibited biofilm formation at concentrations between 10% and 2.5% in all studied strains (P < 0.05), without affecting bacterial growth. BAK inhibited bacterial growth and biofilm formation in all strains between concentrations of 0.042 and 0.375 mg/mL (P < 0.05). CONCLUSIONS AzaSite®, AZM, or BAK prevented biofilm formation by inhibiting growth of AZM-susceptible strains. AzaSite®, AZM, and DuraSite® also reduced biofilm formation at subinhibitory concentrations for growth. Our data indicate that AZM has a moderate inhibitory effect on biofilm formation, whereas DuraSite® appears to play a greater role in the inhibition of staphylococcal biofilm formation by AzaSite®.
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Affiliation(s)
- Eric C Wu
- UPMC Eye Center, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA
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Nguyen D, Emond MJ, Mayer-Hamblett N, Saiman L, Marshall BC, Burns JL. Clinical response to azithromycin in cystic fibrosis correlates with in vitro effects on Pseudomonas aeruginosa phenotypes. Pediatr Pulmonol 2007; 42:533-41. [PMID: 17469154 DOI: 10.1002/ppul.20620] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A 6-month clinical trial of azithromycin (AZM) in American cystic fibrosis (CF) patients with chronic Pseudomonas aeruginosa infection showed clinical improvement without significant reduction in bacterial density. Sub-inhibitory AZM has been hypothesized to affect P. aeruginosa virulence, partly contributing to the mechanism of action of AZM. To correlate bacterial phenotypes of P. aeruginosa isolates with clinical response to AZM in CF patients. Pre-treatment P. aeruginosa isolates from subjects randomized to AZM in the US trial were characterized for bacterial phenotypes: AZM minimal inhibitory concentration (MIC), mucoidy, and baseline and AZM effects on twitching and swimming motility, and production of pyocyanin, protease and phospholipase C (PLC). Initial analyses of a subset of subjects identified phenotypes most strongly associated with FEV(1) response and pulmonary exacerbation. These phenotypes were subsequently characterized and tested in isolates from subjects of the complete AZM cohort. Exploratory analyses of the initial subset suggested that the MIC and in vitro change in PLC and swimming motility with AZM were the strongest candidates among the bacterial phenotypes. When tested, only the change in PLC was significantly correlated with the change in FEV(1) (P=0.05), and occurrence and time to pulmonary exacerbation (both P=0.02). In the complete cohort, change in PLC continued to show significant correlation with FEV(1) response (P=0.006), but not exacerbation. The in vitro effect of AZM on PLC correlates with FEV(1) response to AZM. This suggests that AZM anti-virulence effects may be predictive of clinical response and play a role in the mechanism of action of AZM in CF patients.
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Affiliation(s)
- Dao Nguyen
- Children's Hospital and Regional Medical Center, Seattle, Washington, USA
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