We examined the antimicrobial activities of meropenem and other antibiotics against main bacteria isolated from patient blood in Keio university hospital between January and November in 2008. A total of 187 isolates, including 43 Escherichia coli, 23 Klebsiella pneumoniae, 9 Enterobacter cloacae, 22 Pseudomonas aeruginosa, 16 methicillin-susceptible Staphylococcus aureus (MSSA), 24 methicillin-resistant Staphylococcus aureus (MRSA), 50 Staphylococcus epidermidis were tested. Meropenem showed the potent and stable antibacterial activity against Gram-negative bacteria especially compared with our previous testing data. These results suggested that meropenem was first-line antibiotic for serious infections, although over 12 years passed after meropenem was approved in Japan.

Pseudomonas aeruginosa has been reported to be a leading cause of nosocomial infections. We evaluated the characteristics using 903 P. aeruginosa strains that were isolated in Fukuoka University Hospital from 2006 to 2008. Clinical specimens of P. aeruginosa were detected 47.8% from respiratory tract, 24.4% from urine, and were detected from the pus by 18.9%. Age distribution of the patients was 70 years old or older. Antimicrobial susceptibility ratio of isolates of P. aeruginosa from the outpatients against all agents tested except amikacin had more susceptible than it of isolates from the inpatients.

In P. aeruginosa isolates detected from the inpatients, susceptibilities to other antibiotics were about 60% though 93.3% and 83.2% were susceptible to amikacin and piperacillin/tazobactam respectively.

Isolation rate of multidrug-resistant P. aeruginosa (MDRP) in all clinical isolates was 3.3%.

The report of carbapenem use was obligated in our hospital from the experience of the outbreak by MDRP in 2007, and the infection control team came to regulate the administering of antimicrobial agents more than before. Afterwards, the amounts of the antimicrobial agent use except piperacillin/tazobactam have decreased to 69% compared with the previous year. The susceptibility rates of various antimicrobial agents except amikacin have recovered by 10～17%.

These results suggest that there is a necessity for attending to the drug susceptibility and the amount of the antimicrobial agent use.

We investigated the susceptibility to antibacterials of streptococci isolated from 8 medical facilities in Gifu prefecture between 2005 and 2007. Strains used in this study include 118 of Group A streptococci, 89 of Group B streptococci, and 58 of group G streptococci. For Group A streptococci, cefteram and imipenem gave the lowest MIC₉₀ at 0.0078𝜇g/mL, followed by cefditoren and cefcapene at 0.0156 𝜇g/mL and penicillin G, amoxicillin and meropenem at 0.0313𝜇g/mL. For Group B streptococci, cefteram, cefditoren, cefcapene and imipenem gave the lowest MIC₉₀ at 0.0313𝜇g/mL, followed by penicillin G and meropenem at 0.0625𝜇g/mL and amoxicillin at 0.125𝜇g/mL. For Group G streptococci, cefteram and imipenem gave the lowest MIC₉₀ at 0.0078𝜇g/mL, followed by penicillin G, cefditoren, cefcapene and meropenem at 0.0156𝜇g/mL and amoxicillin at 0.0313𝜇g/mL. With Group A and B streptococci, the susceptibility data obtained in this study were compared with those of strains between 2000 and 2001. As for group A streptococci, the MIC₅₀ and MIC₉₀ of 𝛽-lactam agents were about the same as those of previous study, however the MIC₉₀ of quinolones increased about 2.5-fold and resistant strains were found. As for Group B streptococci, the MIC₅₀ and MIC₉₀ of almost all of the antibacterials were about the same as those of the previous study, however the MIC₉₀ of clarithromycin increased about 10-fold, indicating that the resistant strains are widely spread.