[Multicenter surveillance of Pseudomonas aeruginosa strains for antimicrobials in Aichi prefecture in 2009].

We investigated the susceptibility to antimicrobials of 204 Pseudomonas aeruginosa strains isolated from 21 hospitals in Aichi prefecture from September to November 2009. MIC distributions of various antimicrobials were analyzed in terms of geographic region of isolation, patient status (outpatient or inpatient), and type of specimens that the strain was isolated from. The results were as follows. 1. Although more than 90% of strains were susceptible to all aminoglycosides and colistin, 80-90% of them were susceptible to beta-lactams and fluoroquinolones. MIC distributions of all antimicrobials measured were not significantly different between regions. 2. Only 1 strain (0.5%) was multi-drug resistant Pseudomonas aeruginosa (MDRP). Thirteen strains (6.4%) showed imipenem MIC > or = 16 microg/mL, and 16 strains (7.8%) showed ciprofloxacin MIC > or = 4 microg/mL. These strains tended to be more isolated from urine, respiratory tract specimens, or surgical specimens. 3. The MICs of tazobactam/piperacillin, panipenem, meropenem, doripenem, biapenem, sulbactam/cefoperazone, cefepime, and aztreonam were significantly higher in strains isolated from inpatients than in those from outpatients. MIC distributions of antimicrobials other than beta-lactams were not significantly different between situations where strains were isolated. 4. MIC distributions of piperacillin, all carbapenems, cefepime, gentamicin, and all fluoroquinolones were significantly different among samples from which strains were isolated. The strains isolated from blood showed lower MICs against all antimicrobials than those from other samples. No difference was found in MIC distributions when categorized according to bacteremic origin. The MICs were apparently elevated against beta-lactams, fluoroquinolones, and gentamicin in strains isolated from respiratory tract specimens, and against beta-lactams, and fluoroquinolones in strains isolated from urine. It was suggested that in P. aeruginosa surveillance, the results should be reported by stratifying with patient status, and type of specimens that the strain was isolated from and that regional surveillance should be useful with such stratification to establish antibiograms for empirical antimicrobial choice.

Infective endocarditis caused by multidrug-resistant Streptococcus mitis in a combined immunocompromised patient: an autopsy case report.

An autopsy case of infective endocarditis caused by multidrug-resistant Streptococcus mitis was described in a patient with a combination of factors that compromised immune status, including autoimmune hemolytic anemia, post-splenectomy state, prolonged steroid treatment, and IgA deficiency. The isolated S. mitis strain from blood culture was broadly resistant to penicillin, cephalosporins, carbapenem, macrolides, and fluoroquinolone. Recurrent episodes of bacterial infections and therapeutic use of several antibiotics may underlie the development of multidrug resistance for S. mitis. Because clinically isolated S. mitis strains from chronically immunocompromised patients have become resistant to a wide spectrum of antibiotics, appropriate antibiotic regimens should be selected when treating invasive S. mitis infections in these compromised patients.