The bacteria isolated from the patients with lower respiratory tract infections were collected by institutions located throughout Japan, since 1981. IKEMOTO et al. have been investigating susceptibilities of these isolates to various antibacterial agents and antibiotics, and analyzed some characteristics of the patients and isolates from them each year. Results obtained from these investigations are discussed.
In these 17 institutions around the entire Japan, 512 strains of presumably etiological bacteria were isolated mainly from the sputa of 440 patients with lower respiratory tract infections during the period from October in 1997 to September in 1998. MICs of various antibacterial agents and antibiotics were determined against 100 strains of Staphylococcus aureus, 81 strains of Streptococcus pneumoniae, 85 strains of Haemophilus influenzae, 71 strains of Pseudomonas aeruginosa (non-mucoid strains), 27 strains of Pseudomonas aeruginosa (mucoid strains), 33 strains of Moraxella subgenus Branhamella catarrhalis, 17 strains of Klebsiella pneumoniae etc., and the susceptibilities of these strains were assessed except for those strains that died during transportation.
S. aureus strains for which MICs of oxacillin (MPIPC) were higher than 4 μg/ml (methicillin-resistant S. aureus: MRSA) accounted for 55.0%. The frequency of the drug resistant bacteria decreased comparing to the previous year's 67.3%. Arbekacin (ABK) and vancomycin (VCM) showed the most potent activities against MRSA. Imipenem (IPM) and panipenem (PAPM) of carbapenems showed the most potent activities with MIC80s of 0.063 μg/ml against S. pneumoniae. The frequency of penicillin (PC)-intermediate S. pneumoniae (PISP) + PCresistant S. pneumoniae (PRSP) had decreased gradually, that is, in 1995 the frequency of it was 40.3%, but that was 30.9% in 1997. Against H. influenzae and M.(B.) catarrhalis, all the drugs showed good activities. But the sensitive strains of them against ceftazidime (CAZ) had decreased in 1997, compared those in 1995 and 1996. Meropenem (MEPM), IPM and tobramycin (TOB) showed the most potent activity against P. aeruginosa (mucoid strains). And TOB and ciprofloxacin (CPFX) showed the most potent activities against P aeruginosa (non-mucoid strains). All drugs except ampicillin (ABPC) were more active against K. pneumoniae in 1997 than that in 1996.
Also, we investigated year to year changes in the characteristics of patients, their respiratory infectious diseases, and the etiology. The examination of age distribution indicated that the proportion of patients with ages over 70 years was 45.5% of all the patients showing a slight increase year by year. About the proportion of diagnosed diseases, not so particular changes were recognized as follows: Bacterial pneumonia and chronic bronchitis were the most frequent with 33.6% and 29.1%, respectively. Number of strains isolated from patients before administration of antibiotics were more than those after administration of them in chronic bronchitis, but these had reversed in bacterial pneumonia. The tendency in bacterial pneumonia had been acknowledged since 1995. The increase of S. aureus and P. aeruginosa (both mucoid and non-mucoid strains) isolated after administration of antibiotics, has suggested the decrease of the susceptibility of these strains against antibiotics. Administration of antibiotics has changed the results of the frequency of isolation of bacterial species. Bacterial isolations before administration of antibiotics were as follows: S. pneumoniae 24.5%, H. influenzae 21.4%, S. aureus 18.4% and P aeruginosa 12.2%. The frequencies of S. aureus decreased after antibiotics administration over 15 days, but the frequencies of P. aeruginosa was not affected.

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The annual multicenter studies on isolated bacteria from infections in general surgery and their antimicrobialsusceptibility have been conducted in 20 facilities in Japan since July 1982. This paper describes the resultsobtained during period from July 1996 to June 1997.
The number of cases investigated as objectives was 217 for one year. A total of 406 strains were isolatedfrom 177 cases (81.6% of total cases). From primary infections 162 strains were isolated, and from postoperativeinfections 244 strains were isolated, respectively. From primary infections, anaerobic bacteria were predominant, while from postoperative infections, aerobic Gram-positive bacteria were predominant.
Among aerobic Gram-positive bacteria, the isolation rate of Enterococcus spp. was the highest. In postoperativeinfections, the majority of them were Enterococcus faecalis, while in primary infections, many of themwere Enterococcus avium. The isolation rate of Staphylococcus spp., especially from postoperative infections, followed that of Enterococcus spp. Among anaerobic Gram-positive bacteria, Peptostreptococcus spp. and
Streptococcus spp. were commonly isolated from both types of infections. Among aerobic Gram-negativebacteria, Escherichia coli was the most predominantly isolated from primary infections, followed by Klebsiellapneumoniae and Pseudomonas aeruginosa in this order, and from postoperative infections, P aeruginosa was themost predominantly isolated, followed by E. coli and Enterobacter cloacae. Among anaerobic Gram-negativebacteria, Bacteroides fragilis group was the majority of isolates from both types of infections.
The isolation rate of aerobic Gram-negative bacillus has decreased with time, while those of anaerobes likeB.fragilis group and of aerobic Gram-positive bacteria have gradually increased in both types of infections.
We found vancomycin-resistant strains of neither Staphylococcus aureus nor Enterococcus spp.; however, the MIC of arbekacin for one of strains of S. aureus was 100μg/ml. Both the MIC90's of meropenem andimipenem/cilastatin against P aeruginosa isolated in this term were 25μg/ml, which were higher than thoseagainst the strains isolated in the previous years. Compared with the isolated strains in the year 1995, progress of resistance against carbapenem antibiotics was confirmed.

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The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) offaropenem (FRPM) more compared with those of various oral β-lactams against 15 isolates each of 6 species ofmicroorganism. FRPM possessed potent IN VITRO antibacterial activity against both aerobic and anaerobic Grampositivebacteria tested. FRPM showed the same activity as new oral cephems such as cefdinir, cefditoren andcefcapene against all Gram-negative bacteria, but K.pneumoniae strains were less susceptible. The MBC of FRPM against S. pneumoniae and the other strains tested equal and were within 1 dilution the MIC of that, respectively. These results suggest that FRPM has excellent IN VITRO bactericidal activity against clinical isolates and is a clinically useful for the chemotherapy of bacterial infections.

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Drug sensitivity of clinically isolated bacteria to cefozopran (CZOP), which is a new cephem antibiotic, wasinvestigated, and the usefulness of the drug was evaluated from the viewpoint of bacteriological and clinical (pneumonia) break points. The following results were obtained.
1. According to bacteriological break points, methicillin-resistant Staphylococcus aureus (MRSA) andEnterococcus spp. showed low sensitivity to cefozopran (CZOP). However, the sensitivity of methicillin-sensitiveStaphylococcus aureus (MSSA), E. coli, and Klebsiella spp., which are often isolated as pathogens of commoninfections, was 100%, that of Enterobacter spp., Serratia sp., and Citrobacter sp. was 90% or higher, and that ofPseudomonas aeruginosa was 80% or higher; the values were comparable to or better than those for ceftazidime (CAZ). These results suggest a expandedantibacterial spectrum and enhanced antibacterial potency of CZOP.
2. The estimated response rate of pneumonia to CZOP was 87.5% in outpatients and 51.9% in inpatients. Therefore, CZOP is considered to be oneof the first choices especially in outpatient empiric therapy.

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