Efficacy and Safety of 3-day Azithromycin Treatment of Community Acquired Pneumonia in Patients with and Macrolide- Resistant Streptococcus pneumoniae Infection

6 Jul, 21

Introduction

Azithromycin is a semisynthetic, acid-stable erythromycin derivative with an expanded spectrum of antimicrobial activity that includes commonly isolated pathogens in community-acquired pneumonia (CAP).

Aim

To evaluate the efficacy and tolerability of a 3-day course of azithromycin in adults with mild to moderately severe CAP, and to determine whether in vitro macrolide resistance among strains of S. pneumoniae is related to clinical efficacy/failure.

Patient Profile

Adults with mild to moderately severe CAP

Methods

Open-label, non-comparative study

Endpoints

The primary endpoint was the clinical response on day 8, which was assessed using the JRS clinical response criteria (20).
The clinical response was rated as ‘good’ if 3 of the following 4 outcomes were achieved
- 1) resolution of fever (temperature <37°C)
- 2) resolution of leukocytosis (normalization of WBC count)
- 3) improvement of serum CRP (decreased to <30% of the highest value)
- 4) significant improvement of chest x-ray findings
Secondary endpoints included the microbiological response (assessed by the presence/absence of the infecting micro-organism in the sputum on days 4 and 8), and safety variables assessed via the occurrence of adverse events and laboratory abnormalities.

Results

Figure 1: Summary of clinical and microbiological responses to azithromycin

Azithromycin resistance, based on CLSI criteria, was demonstrated in 85.7% (12/14) of S. pneumoniae isolates, and the presence of ermB genes was found in 50.0% (7/14)
6 of 7 patients in whom high-level resistance was documented (MICs > 256 ?g/mL and carrying ermB genes) exhibited good clinical responses

Figure 2: Clinical and microbiological responses to azithromycin treatment in patients in whom either S. pneumonia or H. influenzae were isolate

Safety

Azithromycin was well tolerated; adverse events, mainly of a gastrointestinal nature, were recorded in 6 patients (7.7%).

Diarrhea (mild and resolved on the same or following day) in 2, abdominal pain/discomfort (mild and resolved on the same day) in 1,
An elevation of ?-glutamyltranspeptidase (GGT) from 46 to 51 U/L in 1, and unspecified events in 2

Conclusion

A 3-day course of azithromycin was effective first-line treatment for adults with mild to moderately severe CAP
Treatment provided advantages for patients in terms of convenience, encouragement of medication compliance, and clearance of symptoms

Reference

Inter Med 2009;48: 527-535