The population pharmacokinetics on tazobactam/piperacillin (TAZ/PIPC; 1 : 8, 4.5 g×3) was analyzed in Japanese patients with community-acquired pneumonia using the Nonlinear Mixed Effect Model version VI. Analysis by the one-compartment model yielded the following results for PIPC: total clearance (CL)=8.22+(Ccr-71.4)×0.0561 (L/hr), distribution volume (Vd)=13.7 (L). The pharmacokinetic parameters for TAZ were: CL=8.67+(Ccr-71.4)×0.0682 (L/hr), Vd=14.4 (L). Of the pharmacokinetic parameters of PIPC, CL included Ccr as a variation factor, whereas the Vd included no variation factor. Because PIPC is excreted into the urine in the unchanged form, its pharmacokinetic factors seem to reflect the renal function status. In this study of patients with community-acquired pneumonia, the mean Vd per body weight was 0.26L/kg, and the results suggested an increase of the Vd in patients with community-acquired pneumonia as compared with the value in healthy adults.

Case report Bacterial meningitis is a rare complication of adenotonsillectomy. We present a case of meningitis due to nontypeable Haemophilus influenzae and Streptococcus pneumoniae after adenotonsillectomy. Pulsed-field gel electrophoresis patterns indicated that the oral cavity was the source of H. influenzae and S. pneumoniae isolated from the cerebrospinal fluid.

Blood culture study As bacteremia is thought to be one of the etiologies of meningitis, we prospectively investigated the rate of bacteremia as a complication of adenotonsillectomy. Of the 46 patients included in the study, mean age of five years old, 11 (24%) had positive blood cultures during the operation. H. influenzae was the commonest organism grown (seven cultures), three of seven produced 𝛽-lactamase, followed by S. pneumoniae (one culture), H. parainfluenzae (one culture), Peptostreptococcus micros (one culture), and Veillonella spp. (one culture). The bacteria were composed of tonsil or adenoid surface cultures in eight of 11 patients (73%).

Conclusions We present a rare case of meningitis complicating a adenotonsillectomy procedure, in a three years old boy. Meningitis is a rare complication of adenotonsillectomy, but bacteremia which may lead to meningitis occurs frequently, as the results.

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 𝛽-lactams and fluoroquinolones. MIC distributions of all and fluoroquinolones. MIC distributions of ll 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≥16𝜇g/mL, and 16 strains (7.8%) showed ciprofloxacin MIC≥4𝜇g/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 𝛽-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 𝛽-lactams, fluoroquinolones, and gentamicin in in strains isolated from respiratory tract specimens, and against 𝛽-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.