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

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.

Invasive pneumococcal disease in patients infected with HIV: still a threat in the era of highly active antiretroviral therapy.

We studied all human immunodeficiency virus (HIV)-infected patients with invasive pneumococcal disease who received their diagnosis during 1996-2002 to investigate the incidence of this disease in the highly active antiretroviral therapy era and to study the influence of CD4 lymphocyte count on the clinical presentation and outcome of disease. The overall incidence of invasive pneumococcal disease was 11.3 cases per 100,000 person-years in adult patients without known HIV infection and 677 cases per 100,000 person-years in HIV-infected patients. This incidence remained stable over the study period. Clinical presentation, severity of illness, and number of recurrent episodes were similar in patients with CD4+ cell counts of >200 or < or =200 cells/ microL. Patients receiving trimethoprim-sulfamethoxazole (TMP-SMZ) were more likely to present with TMP-SMZ-resistant pneumococci than were those who were not receiving this agent (76.7% vs. 43.6%; P=.007). The mortality rate was high (21%).