Bacteria isolated from infections in abdominal surgery during the period from April 2007 to March 2008 were investigated in a multicenter study in Japan, and the following results were obtained.

In this series, 707 strains including 24 strains of Candida spp. were isolated from 181 (79.0%) of 229 patients with surgical infections. Three hundred and ninety-five strains were isolated from primary infections, and 288 strains were isolated from postoperative infections. From primary infections, anaerobic Gram-negative bacteria were predominant, followed by aerobic Gram-negative bacteria, while from postoperative infections aerobic Gram-positive bacteria were predominant, followed by anaerobic Gramnegative bacteria. Among aerobic Gram-positive bacteria, the isolation rate of Enterococcus spp. was highest, followed by Streptococcus spp., and Staphylococcus spp. in this order, from primary infections, while Enterococcus spp. was highest, followed by Staphylococcus spp. from postoperative infections. Among aerobic Gram-negative bacteria, Escherichia coli was the most predominantly isolated from primary infections, followed by Klebsiella pneumoniae, Pseudomonas aeruginosa and Enterobacter cloacae, in this order, and from postoperative infections, P. aeruginosa was most predominantly isolated, followed by E. cloacae, E. coli and K. pneumoniae. Among anaerobic Gram-positive bacteria, the isolation rate of Parvimonas micra was the highest from primary infections, followed by Streptococcus constellatus and Gemella morbillorum, and from postoperative infections, Anaerococcus prevotii was most predominantly isolated. Among anaerobic Gram-negative bacteria, the isolation rate of both Bacteroides fragilis and Bilophila wadsworthia were the highest from primary infections, followed by Bacteroides thetaiotaomicron and Campylobacter gracilis, and from postoperative infections, B. thetaiotaomicron was most predominately isolated, followed by B. fragilis, Bacteroides caccae and B. wadsworthia in this order. In this series, we noticed no vancomycin-resistant Gram-positive cocci, nor multidrugresistant P. aeruginosa. There were nine strains of coagulase-negative Staphylococci which show higher MIC against teicoplanin more than 4μg/mL, but all of them had good susceptibilities against various anti-MRSA antibiotics. We should carefully follow up B. wadsworthia which was resistant to various antibiotics, and also Bacteroides spp. which was resistant to many β-lactam antibiotics.

We examined the frequency of ampicillin (ABPC) resistance of 3784 strains of Haemophilus influenzae isolated from the infants aged from 1 month after birth to 12 years who had been treated in the Pediatric Department of our hospital for 9 years and 6 months from July 1999 to December 2008. We determined the drug susceptibility by Etest, and judged the resistance by the standard of Clinical and Laboratory Standard Institute. The rate of strains of MIC of less than 2𝜇g/ml to ABPC was 87.1% in 1999, but the ratio was decreasing year after year significantly up to 28.7% in 2008 (p<0.001). 𝛽-lactamase negative ABPC resistant (BLNAR) strains whose MIC to ABPC was more than 4𝜇g/ml was 2.9% in 1999, but increased significantly to 43.3% in 2008 (p<0.001). MIC₉₀ was 2𝜇g/ml in 1999, but increased to 16𝜇g/ml in 2008.

We have reported in this journal in vitro susceptibilities of clinical isolates to antibiotics every year since 1992. In this paper, we report the results of an analysis of in vitro susceptibilities of 12,919 clinical isolates from 72 centers in Japan to selected antibiotics in 2007 compared with the results from previous years.

The common respiratory pathogens, Streptococcus pyogenes, Streptococcus pneumoniae, Moraxella catarrhalis and Haemophilus influenzae maintained a high susceptibility to fluoroquinolones (FQs). The resistance of S. pyogenes to macrolides has been increasing every year and this was especially clear this year. Most strains of Enterobacteriaceae except for Escherichia coli showed a high susceptibility to FQs. Almost 30% of E. coli strains were resistant to FQs and the resistance increased further this year. FQs resistance of methicillin-resistant Staphylococcus aureus (MRSA) was approximately 95% with the exception of 45% for sitafloxacin (STFX). FQs resistance of methicillin-susceptible S. aureus (MSSA) was low at about 10%. FQs resistance of methicillin-resistant coagulase negative Staphylococci (MRCNS) was higher than that of methicillin-susceptible coagulase negative Staphylococci (MSCNS), but it was lower than that of MRSA. However, FQs resistance of MSCNS was higher than that of MSSA. FQs resistance of Enterococcus faecalis was 22.5% to 29.6%, while that of Enterococcus faecium was more than 85% except for STFX (58.3%). In clinical isolates of Pseudomonas aeruginosa derived from urinary tract infections, FQs resistance was 21–27%, which was higher than that of P. aeruginosa from respiratory tract infections at 13–21%, which was the same trend as in past years. Multidrug resistant strains accounted for 5.6% in the urinary tract and 1.8% in the respiratory tract. Acinetobacter spp. showed high susceptibility to FQs. The carbapenem resistant strains, which present a problem at present, accounted for 2.7%. Neisseria gonorrhoeae showed high resistance of 86–88% to FQs.

The results of the present survey indicated that although methicillin-resistant Staphylococci, Enterococci, E. coli, P. aeruginosa, and N. gonorrhoeae showed resistance tendencies, and other species maintained high susceptibility rates more than 90% against FQs, which have been used clinically for over 15 years.