Antimicrobial susceptibility patterns for pathogens isolated from patientsin Latin American medical centers with a diagnosis of pneumonia: Analysis of results from the SENTRY Antimicrobial Surveillance Program (1997)
Hs. Sader et al., Antimicrobial susceptibility patterns for pathogens isolated from patientsin Latin American medical centers with a diagnosis of pneumonia: Analysis of results from the SENTRY Antimicrobial Surveillance Program (1997), DIAG MICR I, 32(4), 1998, pp. 289-301
Pneumonia is the mosi common fatal hospital-acquired infection, with attrib
utable mortality rates ranging from 30 to 60%. Rapid initiation of optimal
antimicrobial therapy is essential for obtaining treatment success. In this
report the antimicrobial susceptibility of 556 strains from the lower resp
iratory tract were collected by the SENTRY Antimicrobial Surveillance Progr
am (1997). These strains were isolated from hospitalized patients with pneu
monia in 10 Latin American centers (6 countries) as part of this 68-center
worldwide program. The isolates were susceptibility tested against more tha
n 70 drugs (35 reported by) the reference broth microdilution method. Klebs
iella pneumoniae and Escherichia coli phenotypically consistent with extend
ed spectrum beta-lactamase (ESBL) production were characterized further by
ribotyping and pulsed-field gel electrophoresis. The five most frequently i
solated species mere (n/%): Pseudomonas aeruginosa (149/26.8%), Staphylococ
cus aureus (127/22.8%), Acinetobacter spp. (66/11.9%), Klebsiella spp. (56/
10.1%), and Enterobacter spp. (40/7.2%). P. aeruginosa demonstrated high ra
tes of resistance to a majority of the antimicrobial drugs tested. Carbapen
ems, amikacin, and piperacillin/tazobactam demonstrated the highest suscept
ibility rates (73.8-77.2%) against P. aeruginosa, however the lowest resist
ance rate was observed for cefepime (6.7%). Acinetobacter spp, also showed
very high rates of resistance and the most active compounds were imipenem a
nd meropenem (89.0% susceptibility) followed by the tetracyclines. Cephalos
porin susceptibilities among Klebsiella spp. were low: cefoxitin, 73.0%; ce
ftazidime, 69.4%; and ceftriaxone, 65.9%. Approximately 37% and 28% of K. p
neumoniae and E. coli isolates, respectively, were considered ESBL producer
s based on NCCLS criteria. Ceftriaxone was active against only 52.5% of Ent
erobacter spp. isolates, whereas cefepime uns active against 90.0% of isola
tes (MIC50, less than or equal to 0.12 mu g/mL). Oxacillin resistance was d
etected in nearly 50% of S. aureus isolates. The most active drugs against
S. aureus were vancomycin, teicoplanin, and quinupristin/dalfopristin (MIC9
0, 1 mu g/mL). In summary, our study of pneumonias in Latin American medica
l centers demonstrated a greatly increased prevalence of Acinetobacter spp,
and higher resistance rates among Gram-negative bacilli when compared with
similar controlled studies from North America. (C) Elsevier Science Inc.