Influence of penicillin resistance on outcome in adult patients with invasive pneumococcal pneumonia: is penicillin useful against intermediately resistant strains?

Abstract

OBJECTIVES:

To compare outcome between patients with pneumonia due to penicillin-susceptible S. pneumoniae and patients with pneumonia due to penicillin intermediately resistant strains and to study the outcome of patients with pneumococcal pneumonia caused by strains with MICs of 0.12-1 mg/L treated empirically during the first 48 h with beta-lactam antibiotics.

MATERIALS AND METHODS:

We studied 247 adult patients with invasive pneumococcal pneumonia occurring from 1997 to 2001. The following data were recorded from each patient: socio-demographic characteristics, underlying diseases, clinical presentation, initial severity of pneumonia, initial and subsequent antimicrobial therapy, in-hospital complications, hospital mortality and length of hospital stay. Multivariate analysis was done to identify variables associated with the development of pneumonia caused by a non-susceptible strain.

RESULTS:

The overall presence of penicillin non-susceptibility was 26.7%; no strain had an MIC >2 mg/L. Overall mortality was 23.5% in patients with pneumonia caused by intermediately resistant pneumococci and 12.7% in those with pneumonia caused by susceptible strains (P=0.075). Mortality during the first 7 days of admission, considered to be pneumonia-related deaths (13.7% versus 9.9%; P=0.448) was similar in both groups. The multivariate analysis showed that serotype 14 (OR, 140.18; 95% CI, 16.95-1159.20), serotype 19 (OR, 7.53; 95% CI, 1.98-28.7), haematological malignancy or splenectomy (OR, 4.46; 95% CI, 1.5-13.23) and HIV infection (OR, 4.54; 95% CI, 1.54-13.44) were the only independent factors associated with pneumonia caused by penicillin intermediately resistant pneumococci. In patients with strains having MICs of 0.1-1 mg/L, overall mortality was similar in the group of penicillin-treated patients (22.2%) to those treated with broad-spectrum beta-lactams (23.5%).

CONCLUSIONS:

There is a non-significant trend to higher mortality in patients with pneumococcal pneumonia caused by intermediately resistant strains; however, they do not have a poorer outcome when they are treated with amoxicillin.

• Authors: Vicenç Falcó, Benito Almirante, Queralt Jordano, Laura Calonge, Oscar del Valle, Carles Pigrau, Ana María Planes, Joan Gavaldà, Albert Pahissa
• Journal: The Journal of antimicrobial chemotherapy (J Antimicrob Chemother) Vol. 54 Issue 2 Pg. 481-8 (Aug 2004) ISSN: 0305-7453 [Print] England
• PMID: 15215226 (Publication Type: Comparative Study, Journal Article)

Chemical References

• Anti-Bacterial Agents
• Penicillins
• Erythromycin
• Amoxicillin

Topics

• Adult
• Aged
• Amoxicillin (therapeutic use)
• Anti-Bacterial Agents (pharmacology, therapeutic use)
• Critical Care
• Erythromycin (pharmacology)
• Female
• Hospitalization
• Humans
• Immunologic Deficiency Syndromes (complications)
• Male
• Microbial Sensitivity Tests
• Middle Aged
• Multivariate Analysis
• Penicillin Resistance
• Penicillins (therapeutic use)
• Pleura (microbiology)
• Pneumonia, Pneumococcal (drug therapy, microbiology, mortality)
• Risk Assessment
• Spain (epidemiology)
• Streptococcus pneumoniae (drug effects)
• Treatment Outcome