[Activity of ertapenem and 19 other antimicrobial agents against beta-lactam-resistant Streptococcus pneumoniae and Haemophilus influenzae respiratory tract isolates].
BACKGROUND
Ertapenem is a new carbapenem with a long half-life that has a broad spectrum of action against Gram-positive and Gram-negative bacteria. Although, clinically indicated for the treatment of the polymicrobial abdominal infection, other uses are possible, due to the broad spectrum of action of this antimicrobial agent.


OBJECTIVE
The purpose of this study was to examine the susceptibility to ertapenem of Streptococcus pneumoniae and Haemophilus influenzae strains with resistance to beta-lactam antibiotics.


METHODS
The study comprised 105 S. pneumoniae strains with a reduced susceptibility to penicillin G, 86 S. pneumoniae strains resistant to penicillin, and 100 H. influenzae strains resistant to ampicillin isolated fron clinical respiratory samples collected in the 21 participating microbiology laboratories. Susceptibility to antimicrobials was tested using an agar dilution method.


RESULTS
The S. pneumoniae strains with intermediate resistance to penicillin were highly susceptible to carbapenems, with MIC90 of 0,25 and 0,5 mg/l for imipenem and ertapenem, respectively. Among the penicillin-resistant strains the MIC90 values for imipenem and ertapenem were 1 and 2 mg/l respectively. Carbapenems were very active against the whole group of H. influenzae strains, particullary ertapenem, which inhibited 90% of the series at a concentration of 0,12 mg/l.


CONCLUSIONS
Ertapenem is a powerful agent against the most common respiratory bacterial pathogens, including those with resistance mechanisms effective against other compouunds. Few strains can currently be considered resistant to this carbapenem, which is at least comparable to imipenem, cefotaxime or the modern fluorquinolones. Such performance, and its favorable pharmacokinetic characteristics, make ertapenem an interesting option for the treatment of respiratory tract infections.
Gómez-Garcés
José Luis
JL
Servicio de Microbiología, Hospital de Móstoles, Instituto Madrileño de la Salud, Rio Jucar s/n, 28935 Móstoles, Madrid, Spain. jlgarces@microb.net
Alós
Juan Ignacio
JI
Alhambra
Almudena
A
Hernáiz
Carmen
C
D000328:Adult; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001424:Bacterial Infections / Q000453:epidemiology / Q000382:microbiology*; D002648:Child; D024901:Drug Resistance, Multiple, Bacterial; D000077727:Ertapenem; D006193:Haemophilus influenzae / Q000187:drug effects*; D006801:Humans; D007769:Lactams / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D010400:Penicillin G / Q000494:pharmacology; D010403:Penicillin Resistance; D012141:Respiratory Tract Infections / Q000453:epidemiology / Q000382:microbiology*; D013030:Spain / Q000453:epidemiology; D013296:Streptococcus pneumoniae / Q000187:drug effects*; D018440:beta-Lactam Resistance; D047090:beta-Lactams
D000900:Anti-Bacterial Agents; D007769:Lactams; D047090:beta-Lactams; D000077727:Ertapenem; D010400:Penicillin G