The spread of extended-spectrum-␤-lactamase (ESBL)-producing organisms, particularly those harboring the CTX-M-type enzymes, both in the hospital and in the community, is difficult to discontinue due to the successful mobilization and evolution of the genetic elements harboring ESBL genes and coresistance rates in these isolates. The activities of tigecycline against 285 non-clonally related isolates (172 from Escherichia coli, 84 from Klebsiella spp., 20 from Enterobacter spp., 5 from Salmonella spp., and 4 from Citrobacter spp.) expressing well-characterized ESBLs and recovered in our hospital and its community area of influence were comparatively assessed (CLSI microdilution). Susceptibility rates for meropenem, imipenem, tigecycline, amikacin, and piperacillin-tazobactam were 100%, 100%, 97.5%, 93.3%, and 93%, respectively. Tigecycline (mode MIC, 0.5 g/ml; MIC 90 , 1 g/ml) was 4-to 256-fold more active than doxycycline and minocycline (mode MIC range, 2 to 128 g/ml). CTX-Ms were the most frequent ESBLs (61.4%), 65.8% in community and 58.6% in nosocomial isolates. CTX-M-9 (22%), CTX-M-14 (15.8%), and CTX-M-10 (14%) were the most represented derivatives. SHV and TEM variants constituted 22.8% and 15.8% of the ESBLs, respectively. Overall coresistance rates were as follows: gentamicin, 27.4%; tobramycin, 27.4%; amikacin, 6.7%; and chloramphenicol, 29.1%. Sulfonamide (61.7%), trimethoprim (52.3%), streptomycin (50.5%), and ciprofloxacin (37.2%) resistance levels were significantly (P < 0.001) associated with CTX-M-9 producers. No tigecycline resistance was observed, although seven Klebsiella pneumoniae isolates exhibited intermediate MICs (4 g/ml). Tigecycline, lacking cross-resistance with other compounds, could represent an opportunity to reduce the intensity of selection for ESBL-producing organisms derived from the use of other antimicrobial agents. However, this in vitro promise requires support from clinical studies.

Streptococcus pneumoniae no longer has predictable antibiotic susceptibility. There are two areas of high prevalence of resistance (over 25%) to beta-lactam antibiotics in the South-West and North-East of Europe. In Spain, a close relationship has been found between the yearly rate of aminopenicillin consumption and penicillin resistance. High level resistance (MIC greater than or equal to 1 mg/L) has developed against a previous background of low level resistance. The serotypes involved in penicillin resistance in Spain are widespread in other countries. Macrolide resistance is high in France (over 15%) and is also increasing in other countries. All these resistant isolates remain susceptible to the most recent fluoroquinolones, such as temafloxacin. Prospective surveillance, more rational use of antibiotics and a diversification of antibiotic use in respiratory tract infections may serve to limit the threat of antibiotic resistance in S. pneumoniae.

(n ‫؍‬ 52) at the Hospital Universitario Ramón y Cajal were reidentified on the basis of their genetic traits using new taxonomic criteria. Initial identification was performed by the semiautomatic Wider system (Fco. Soria-Melguizo, Spain) and the API 20 Strep system (bioMérieux, France). All isolates were reidentified by PCR amplification and sequencing of both the 16S rRNA and sodA genes and by mass spectrometry using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS; Bruker, Germany). Results of 16S rRNA/sodA gene sequencing were as follows: Streptococcus gallolyticus subsp. gallolyticus, 14/14 (number of isolates identified by 16S rRNA/number of isolates identified by sodA gene sequencing); Streptococcus gallolyticus subsp. pasteurianus, 24/24; Streptococcus spp., 7/0; Streptococcus infantarius subsp. infantarius, 0/2; Streptococcus lutetiensis, 0/5; Leuconostoc mesenteroides, 4/0; and Lactococcus lactis, 3/3. MALDI-TOF MS identified 27 S. gallolyticus isolates but not at the subspecies level, 4 L. mesenteroides isolates, 3 L. lactis isolates, and 6 S. lutetiensis isolates, whereas 12 isolates rendered a nonreliable identification result. Pulsed-field gel electrophoresis grouped all S. gallolyticus subsp. gallolyticus isolates into 3 major clusters clearly different from those of the S. gallolyticus subsp. pasteurianus isolates, which, in turn, exhibited no clonal relationship. The percentages of resistance to the tested antimicrobials were 38% for erythromycin, 23% for fosfomycin, 10% for levofloxacin, 6% for tetracycline, and 4% for co-trimoxazole. The most frequent underlying diseases were hepatobiliary disorders (53%), endocarditis (17%), and malignancies (12%). We conclude that sequencing of the sodA gene was the most discriminatory method and that S. gallolyticus subsp. pasteurianus appears to have a higher genetic diversity than S. gallolyticus subsp. gallolyticus.