Nationwide surveillance of bacterial respiratory pathogens conducted by the Japanese Society of Chemotherapy in 2007: general view of the pathogens' antibacterial susceptibility

For the purpose of a nationwide surveillance of the antimicrobial susceptibility of bacterial respiratory pathogens in patients in Japan, the Japanese Society of Chemotherapy conducted their second year survey, during the period from January to August, 2007. A total of 1178 strains were collected from clinical specimens obtained from adult patients with well-diagnosed respiratory tract infections. Susceptibility testing was evaluable for 1108 strains (226 Staphylococcus aureus, 257 Streptococcus pneumoniae, 6 Streptococcus pyogenes, 206 Haemophilus influenzae, 120 Moraxella catarrhalis, 122 Klebsiella pneumoniae, and 171 Pseudomonas aeruginosa). A total of 44 antibacterial agents, including 26 β-lactams (four penicillins, three penicillins in combination with β-lactamase inhibitors, four oral cephems, eight parenteral cephems, one monobactam, five carbapenems, and one penem), three aminoglycosides, four macrolides (including ketolide), one lincosamide, one tetracycline, two glycopeptides, six fluoroquinolones, and one oxazolidinone were used for the study. Analysis was conducted at the central reference laboratory according to the method recommended by the Clinical and Laboratory Standards Institute (CLSI). The incidence of methicillinresistant Staphylococcus aureus (MRSA) was high, at 59.7%, and the incidences of penicillin-intermediateresistant and -resistant Streptococcus pneumoniae (PISP and PRSP) were 30.4% and 5.1%, respectively. Among Haemophilus influenzae strains, 19.9% of them were found to be β-lactamase-non-producing ampicillin (ABPC)-intermediately-resistant (BLNAI), 29.1% to be β-lactamasenon-producing ABPC-resistant (BLNAR), and 6.7% to be β-lactamase-producing ABPC-resistant (BLPAR) strains. Extended-spectrum β-lactamase-producing Klebsiella pneumoniae was not isolated. Two isolates (1.2%) of Pseudomonas aeruginosa were found to be metallo-β-lactamase-producing strains, including one (0.6%) suspected multidrug-resistant strain showing resistance to imipenem, amikacin, and ciprofloxacin. These data will be a useful reference for future periodic surveillance studies and for investigations to control resistant infections as well. Continued surveillance is required to prevent the further spread of these antimicrobial resistances.