ABSTRACT
Four Enterobacter cloacae clinical isolates with reduced susceptibility to ceftazidime from two hospitals in Thailand were studied. Production of extended-spectrum beta-lactamase was confirmed by double disk synergy test and combination disk method. All isolates were highly resistant to ceftazidime but retained susceptibility to imipenem. One isolate was able to hydrolyze cefotaxime, ceftazidime and cefepime, the latter being one of the treatment choices for infection by Enterobacter spp. PCR analysis demonstrated the presence of bla(SHV12) in addition to bla(TEM-1) in all isolates suggesting that SHV-12 was associated with high-level resistance to ceftazidime in the E. cloacae isolates.
ABSTRACT
A total of 400 clinical Streptococcus pneumoniae strains from patients with respiratory diseases were collected from January 2002 to December 2005. In this study, an increased prevalence of penicillin-nonsusceptible S. pneumoniae (PNSP) from 63% in 2002-2003 to 69% in 2004-2005 was found. During 2004-2005, 56% were erythromycin-nonsusceptible S. pneumoniae (ENSP) and 54% were both PNSP and ENSP. The PNSP, ENSP and PNSP+ENSP groups showed similar trends, ie, sensitive to amoxicillin/clavulanate (range 97.2-98.5%), levofloxacin (range 90.7-92.4%), ceftriaxone (range 87.1-89.4%), and ofloxacin (range 64.8-66.1%). Lower levels of susceptibility were detected for azithromycin, clarithromycin, cefdinir, cefprozil, clindamycin, co-trimoxazole, chloramphenicol and tetracycline in penicillin and erythromycin-nonsusceptible strains. Of the macrolide-resistant S. pneumoniae, 55% of strains exhibited the M phenotype and 45% the constitutive MLS(B) phenotype. No pneumococci with the inducible MLS(B) phenotype were detected in Thailand.