A total of 78 clinical isolates of Streptococcus pyogenes were collected from January 1992 through December 1993 from patients in southern Taiwan. The in vitro activities of 10 antimicrobial agents were determined by the agar dilution method. Penicillin, cephalothin, cefotaxime, vancomycin, and ofloxacin were shown to be active against S. pyogenes isolates, with MICs at which 90% of isolates are inhibited (MIC 90 s) being <0.03, <0.13, <0.13, <0.13, and <0.25 g/ml, respectively. Erythromycin and azithromycin both had poor activities (MIC 50 s, 16 and >128 g/ml, respectively; MIC 90 s, >128 and >128 g/ml, respectively). The activities of tetracycline, clindamycin, and chloramphenicol against a significant number of these isolates were also limited. As the MICs of clindamycin and chloramphenicol for the isolates increased, the MICs of the two macrolides also increased. Clindamycin, chloramphenicol, and the two macrolides were less potent against isolates recovered from throat swab samples than against those from blood or other sources. Isolates of the T12 and T1 serotypes accounted for 53.8% of all isolates. The majority (87.5%) of the isolates recovered from throat swab samples were of the T12 serotype, whereas 19.2% of the isolates recovered from blood were of the T12 serotype. In contrast, 66.7% of the isolates of the T1 serotype were derived from blood but none were derived from throat swab samples. Of the 33 T12 serotype isolates, erythromycin MICs for 78.8% of the isolates were >128 g/ml. Because of the poor activities of erythromycin and azithromycin against S. pyogenes isolates from patients in southern Taiwan, these drugs should no longer be considered the drugs of choice for the management of group A streptococcal infections among patients who live in this area.

No abstract

Our data show that ESBLs, AmpC, and imipenemase-8 (IMP-8) carbapenemase coupled with decreased expression of outer membrane protein were prevalent in Enterobacteriaceae isolates testing positive for the modified Hodge test in Taiwan.

We investigated the prevalence of metallo-β-lactamases (MBLs) among 1,827 Enterobacteriaceae isolates collected in 2006 and evaluated the VITEK 2 microbiology system, modified Hodge test, and 2 combined disk tests as the screening tools for MBLs by using these isolates and 77 previously characterized IMP-8 producers. The IMP-8 MBL was identified in 18 isolates of 2006, and the IMP-8-positive isolates represented 0.2%, 1.1%, and 5.0% of all Escherichia coli, Klebsiella pneumoniae, and Enterobacter cloacae isolates, respectively. Only one-third of all MBL producers could be recognized by either VITEK 2 or the Hodge test. MBL production could be identified in 38 (40%) of the 95 IMP-8-producing isolates by the combined disk test using meropenem disks supplemented by phenylboronic acid and EDTA, and only 2 (2.1%) isolates gave positive results in the combined disk test using meropenem disks supplemented with dipicolinic acid. Of all IMP-8 producers, 37.9%, 50.5%, and 32.6% were nonsusceptible to tigecycline, fluoroquinolones, and both, respectively. In conclusion, this study demonstrated the lack of distinct phenotypes that could be easily identified among the IMP-8-producing Enterobacteriaceae isolates at a Taiwanese hospital. Continuous surveillance and monitoring are needed because the widespread of tigecycline- and fluoroquinolone-coresistant MBL producers may become a serious therapeutic problem.

Anaerobic bacteria can cause a wide variety of infections, and some of these infections can be serious. Conventional identification methods based on biochemical tests are often lengthy and can produce inconclusive results. An oligonucleotide array based on the 16S-23S rRNA intergenic spacer (ITS) sequences was developed to identify 28 species of anaerobic bacteria and Veillonella. The method consisted of PCR amplification of the ITS regions with universal primers, followed by hybridization of the digoxigenin-labeled PCR products to a panel of 35 oligonucleotide probes (17-to 30-mers) immobilized on a nylon membrane. The performance of the array was determined by testing 310 target strains (strains which we aimed to identify), including 122 reference strains and 188 clinical isolates. In addition, 98 nontarget strains were used for specificity testing. The sensitivity and the specificity of the array for the identification of pure cultures were 99.7 and 97.1%, respectively. The array was further assessed for its ability to detect anaerobic bacteria in 49 clinical specimens. Two species (Finegoldia magna and Bacteroides vulgatus) were detected in two specimens by the array, and the results were in accordance with those obtained by culture. The whole procedure of array hybridization took about 8 h, starting with the isolated colonies. The array can be used as an accurate alternative to conventional methods for the identification of clinically important anaerobes.Anaerobic bacteria are important human pathogens, and infections caused by these bacteria can be serious and lifethreatening (6). A recent report from the Mayo Clinic (Rochester, MN) revealed an overall increase in the incidence of anaerobic bacteremias of 74% from 2001 to 2004 compared to that from 1993 to 1996 (20), although the same trend was not found in community hospitals or in an European countries (2, 11). The commonly isolated anaerobic bacteria are the members of the Bacteroides fragilis group and Peptostreptococcus, Clostridium, and Fusobacterium species (3,6,20).Most clinical laboratories use differential biochemical tests for the identification of anaerobic microorganisms (35). However, Simmon et al. (31) found that 24% of the isolates of anaerobic bacteria recovered from blood cultures were misidentified and that 10% isolates were not identified to the species level by phenotypic characteristics. A rapid commercial kit, the Rapid ID 32A kit (bioMérieux, Marcy l'Etoile, France), was evaluated for its ability to identify strains in the Bacteroides fragilis group. The results showed that only 78.4% of the strains were correctly identified to the species level without supplemental tests (15). The success of the Rapid ID 32A system for species identification varied with different taxa (10), and a low identification rate (50%) was observed for fusobacteria (16). Veillonella isolates are relatively easily identified to the genus level, but the differentiation of Veillonella isolates at the species level remains difficult and inconclusive due to the ...