To prevent further development of resistance in respiratory pathogens, a judicious use of antibiotics for respiratory tract infections has been proposed [1]. Recently, Guchev et al. [2] demonstrated that amoxicillin treatment could successfully be targeted by use of the Urinary Antigen Test (UAT) for Streptococcus pneumoniae (Binax) in nonsevere community-acquired pneumonia (CAP). However, 78% of the study patients had negative UAT results and received empirical treatment with claritromycin, in accordance with the CAP guidelines of the American Thoracic Society [3] and the Infectious Disease Society of America [4]. Although antibiotic treatment active against atypical pathogens is routinely recommended in these guidelines, such treatment was not superior to β-lactam monotherapy, unless Legionella species was the cause of infection, in 2 recent meta-analyses of treatment of CAP [5, 6]. Thus, β-lactam monotherapy can be used empirically and does not need to be targeted when used to treat CAP. Is the UAT, then, still useful in the treatment of CAP? Could the test be used to anticipate the course in patients treated with β-lactam monotherapy? In 215 hospitalized CAP patients who have been previously described [7], the treatment choices were based on the clinicians' own decisions. Apart from the UAT, cultures of blood samples and respiratory tract specimens and respiratory tract PCR for Mycoplasma pneumoniae and Chlamydophila pneumoniae were performed for all patients. The UAT and PCR analyses were performed at the end of the study and could not influence the antibiotic choices. The study described in this letter was approved by the ethics committee of the Örebro County Council. β-Lactam monotherapy was the initial hospital treatment for 152 patients (71%), who had a median age of 74 years (range, 18–96 years). Thirty-eight patients (25%) had positive UAT results. The hospital course was considered to be successful if the patient's condition improved and clinically stabilized and if the patient was discharged from the hospital during or after completion of β-lactam monotherapy. Changes in treatment within the β-lactam group were not considered to be failures. The success rates in relation to the result of the UAT are presented in table 1. Overall, the patients with positive test results had a higher success rate than did patients with negative results (P = .034, by the Χ2 test), although 48% of patients with negative test results belonged to severity risk classes IV–V, compared with 39% of patients with positive results. Of the 122 patients with a successful hospital course, 2 patients with negative UAT results died within 30 days after hospitalization. Among the 30 patients who did not have a successful hospital course, only 1 with a negative UAT result died. The remaining 29 patients, including 26 with negative UAT results, were subjected to treatment changes and received treatment with non–β-lactam antibiotics. All of these patients' conditions improved and clinically stabilized, and the patients were discharged from the hospital. Rates of hospital success with β-lactam monotherapy in relation to the results of the Streptococcus pneumoniae urinary antigen test (UAT) in 152 hospitalized patients with pneumonia. Because 149 (98%) of the 152 patients were alive and discharged from the hospital on day 30 of hospitalization, β-lactam monotherapy appears to be a safe initial treatment of CAP. Although the UAT is not needed to target β-lactam monotherapy, it still appears to be useful in the management of CAP. A positive test result can support treatment with narrow-spectrum β-lactam antibiotics and can be used to prevent unnecessary antibiotic changes. The present study shows that antibiotic changes will most often not be needed in patients with positive test results but will be needed more frequently in patients with negative test results. When a UAT result is negative, diagnostic tests for conventional and atypical pathogens are useful to gain support for the ongoing treatment or suggestions for treatment alterations (table 1). Financial support.The study was supported by grants from the Research Committee of Örebro County Council and the Örebro University Hospital Research Foundation. The Binax NOW urinary antigen test kits were purchased from Electra-Box Diagnostica, Stockholm, Sweden, at a 50% discount. Potential conflicts of interest.K.S. and H.H.: no conflicts.
No takes yet. Share an insight, caveat, or question.
Strålin et al. (2005) studied this question.