SAN FRANCISCO, CA—The penicillin class is not inferior to third-generation cephalosporins for the treatment of community-acquired pneumonia (CAP) and may be used with low risk of treatment failure, according to results of a case-control study reported at IDWeek 2013.

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Use of wide-spectrum antibiotics such as third-generation cephalosporins is common in clinical practice; however, such use has the potential to increase antimicrobial resistance, if not expense.

Noting that the penicillin class is included in treatment guidelines for CAP, Shin-Woo Kim, MD, PhD, Internal Medicine, Kyungpook National University Hospital, Daegu, South Korea, and colleagues performed a study that randomly matched 225 patients receiving ampicillin/sulbactam (n=72) or amoxicillin/clavulanate (n=3) or third-generation cephalosporins (n=150) as empiric antibiotics for CAP in a 1:2 ratio.

They also compared the selection bias of choice of empiric antibiotics (penicillins vs. third-generation cephalosporins) that might relate to severity of CAP.

The patients were enrolled between January 2010 and June 2012 from four academic hospitals in Korea. Average age was 60.4 years (range, 19 to 90).

The CURB-65 of the penicillin group was 1.17 ± 1.05, compared with 1.07±0.95 for the third-generation cephalosporin group (P=0.487). The Pneumonia Severity Index scores were 77.5 ± 28.2 vs. 74.7±29.3 (P=0.50), respectively.

When macrolides or fluoroquinolones were combined with penicillins or third-generation cephalosporins in patients treated for CAP, the difference between the two groups reached statistical significance, 68.0% (51/75) for the penicillin group vs. 84% for third-generation cephalosporin (126/150; P=0.009).

Early failure, defined as 72 hours following administration, was 21.38% (16/75) in penicillin group vs. 13.3% (20/150) in the third-generation cephalosporin group (P=0.128).

Treatment failure, defined as 30 days post-administration, was 2.7% (2/75) in penicillin group vs. 1.3% (2/150) in the third-generation cephalosporin, which was not statistically significant.

Multivariate logistic regression analysis with variables such as empiric antibiotics, age, Charlson comorbidity score, presence of combination treatment, and Pneumonia Severity Index score found only the Pneumonia Severity Index to be significant (P=0.022). In addition, early failure of the penicillins (eg, ampicillin/sulbactam or amoxicillin/clavulanate) continued to be nonsignificant (OR 1.68; 95% CI 0.79–3.57; P=0.181).

Dr. Kim and colleagues cautioned that one study limitation was the “relatively small number of patients.” However, the low 30-day mortality of CAP—2.7% in the penicillin group vs. 1.3% in the third-generation cephalosporin group—“supports the use of relatively narrow spectrum antibiotics for empiric antibiotic use against CAP,” they concluded.