[In vitro susceptibilites to levofloxacin and various antibacterial agents of 11,475 clinical isolates obtained from 52 centers in 2002].

The susceptibilities of bacteria to fluoroquinolones (FQs), especially levofloxacin, and other antimicrobial agents were investigated using 11,475 clinical isolates collected in Japan during 2002. Methicillin susceptible staphylococci, Streptococcus pyogenes, Streptococcus pneumoniae, Moraxella catarrhalis, the family of Enterobactericeae, Haemophilus influenzae and Acinetobacter spp. exhibited stable and high susceptibilities to FQs. The rate of FQs-resistant MRSA was 80 approximately 90%, being markedly higher than that of FQs-resistant MSSA. The FQs-resistance rate of MRCNS was also higher than that of MSCNS, however, it was lower than that of MRSA. No FQs-resistant clinical isolates of Salmonella spp. were detected in any of the surveys. Thirteen of Escherichai coli 696 isolates, 8 of Klebsiella pneumoniae 630 isolates and 33 of Proteus mirabilis 373 isolates produced extended-spectrum beta-lactamase (ESBL), furthermore 6 of 13 in E. coli, 1 of 8 in K. pneumoniae and 14 of 31 ESBL-producing isolates, and in P. mirabilis were FQs resistant. Attention should be focused in the future on the emergence of ESBL in relation to FQs resistance. The rate of FQs-resistant P. aeruginosa isolated from urinary tract infection (UTI) was 40 approximately 60%, while 15 approximately 25% of isolates from respiratory tract infection (RTI) were resistant. IMP-1 type metallo beta-lactamase producing organisms were found in 49 of P. aeruginosa 1,095 isolates, 7 of S. marcescens 586 isolates and 4 of Acinetobacter spp. 474 isolates, respectively. Glycopeptide-resistant enterococci or S. aureus was not found.

[Activities of antimicrobial agents against 8,474 clinical isolates obtained from 37 medical institutions during 2000 in Japan].

A survey was conducted to determine the antimicrobial activity of fluoroquinolones and other antimicrobial agents against 8,474 clinical isolates obtained from 37 Japanese medical institutions in 2000. A total of 25 antimicrobial agents were used, comprising 4 fluoroquinolones, 13 beta-lactams, minocycline, chloramphenicol, clarithromycin, azithromycin, gentamicin, amikacin, sulfamethoxazole-trimethoprim, and vancomycin. A high resistance rate of over 85% against fluoroquinolones was exhibited by methicillin-resistant Staphylococcus aureus (MRSA) and Enterococcus faecium. Isolates showing resistance to fluoroquinolones among methicillin-resistant coagulase-negative Staphylococci, Enterococcus faecalis, and Pseudomonas aeruginosa from UTI accounted for 30-60%. However, many of the common pathogens were still susceptible to fluoroquinolones, such as Streptococcus pneumoniae (including penicillin-resistant isolates), Streptococcus pyogenes, methicillin-susceptible S. aureus (MSSA), methicillin-susceptible coagulase-negative Staphylococci, Moraxella catarrhalis, the Enterobacteriaceae family, and Haemophilus influenzae (including ampicillin-resistant isolates). About 85% of P. aeruginosa isolated from RTI were susceptible to fluoroquinolones. In conclusion, this survey of sensitivity to antimicrobial agents clearly indicated trend for increasing resistance to fluoroquinolones among MRSA, Enterococci, and P. aeruginosa isolated from UTI, although fluoroquinolones are still effective against other organisms and P. aeruginosa from RTI as has been demonstrated in previous studies.

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (2001). I. Susceptibility distribution].

The bacterial strains isolated from patients diagnosed as having urinary tract infections (UTIs) in 10 institutions in Japan were supplied between the period of September and December 2001. Then, the susceptibilities of them to a variety of antimicrobial agents were investigated. The number of them were 496 strains. The breakdown of these strains was Gram-positive bacteria as 29.6% and Gram-negative bacteria as 70.4%. Susceptibilities of these bacteria to antimicrobial agents were as follows; against Staphylococcus aureus, vancomycin (VCM) showed a strong activity, and this drug also had a strong activity against MRSA in preventing growth of all strains at 1 microgram/mL. In addition, arbekacin (ABK) showed strong activity with the MIC90 of 2 micrograms/mL against MRSA and prevented growth of all strains at 4 micrograms/mL. ABK also showed a strong activity against Staphylococcus epidermidis in preventing growth of all strains at 0.5 microgram/mL. Ampicillin (ABPC) and cefozopran (CZOP) showed a relatively strong activity against S. epidermidis (MIC90: 8 micrograms/mL). ABPC, imipenem (IPM), and VCM showed strong activities against Enterococcus faecalis. No increase of low-susceptible strains in E. faecalis was observed against these antimicrobial agents. Against Escherichia coli, carbapenems showed the highest activities: meropenem (MEPM) prevented growth of all strains at 0.25 microgram/mL; IPM prevented growth of all strains at 0.5 microgram/mL. CZOP and cefotiam (CTM) also showed strong activities against E. coli: MIC90 of CZOP was within 0.125 microgram/mL; MIC90 of CTM was within 0.5 microgram/mL. Quinolone-resistant E. coli was detected at frequency of 9.3%, which was lower than that in the last year, and was higher level than those in up to 1999. MEPM showed the strongest activity against Citrobacter freundii in preventing growth of all strains at 0.125 microgram/mL. Almost all drugs showed strong activities against Klebsiella pneumoniae and Proteus mirabilis, and MEPM prevented growth of all strains within 0.125 microgram/mL. Against Serratia marcescens, the MIC90 of gentamicin (GM) was the lowest value being 2 micrograms/mL, and those of IPM and carumonam were 8 and 16 micrograms/mL, respectively. Against Pseudomonas aeruginosa, almost all drugs were not so active. The MIC90 of GM was 8 micrograms/mL, those of IPM and amikacin were 16 micrograms/mL, and those of all other drugs were over than 32 micrograms/mL.

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (2001). II. Background of patients].

Five-hundred thirty one bacterial strains isolated from 412 patients diagnosed as having urinary tract infections (UTIs) in 10 institutions in Japan were supplied between September and December 2001. Then, the clinical background of patients were investigated such as sex, age, and type of infections, infections and kind of bacteria, frequency of bacteria isolation by age and infections, bacteria and infections by timing of antibiotics administration, and bacteria and infections by surgical procedures. With regard to the relationship between age and sex of patients and type of infections, the number of cases aged lower than 50 years was few and complicated UTIs without indwelling catheter was the most frequent in male patients. In females, the number of patients aged lower than 20 years was few. Most of female patients aged lower than 80 years had uncomplicated UTIs. As for the relationship between type of infections and kind of bacteria, Escherichia coli decreased as the infections were more complicated, and Pseudomonas aeruginosa and Enterococcus faecalis increased as the infections were more complicated. In relation of these results to age of patients, isolation frequency of E. coli gradually decreased with aging in patients aged 20 years and older with uncomplicated UTIs. The isolation frequencies of E. faecalis decreased with aging in the patients with complicated UTIs without indwelling catheter while P. aeruginosa decreased with aging in the patients with complicated UTIs with indwelling catheter. E. coli was isolated a few after administration of antibiotics, and P. aeruginosa and E. faecalis were frequently isolated after administration in the patients with all types of infections. As for type of causative organisms in UTIs and with or without surgical operation, E. coli was frequently isolated in the patients without surgery in the patients with uncomplicated UTIs and complicated UTIs without indwelling catheter, while P. aeruginosa was frequently isolated in the patients who underwent surgery in the patients with uncomplicated UTIs and complicated UTIs with indwelling catheter. In uncomplicated UTIs, isolation frequencies of Klebsiella spp., P. aeruginosa, and E. faecalis were significant in the patients with surgery. In complicated UTIs without indwelling catheter, Klebsiella spp. was frequently isolated in the patients with surgery. In complicated UTIs with indwelling catheter, S. aureus and Staphylococcus spp. were frequently isolated in the patients without surgery.

Evaluation of a new agar medium containing cetrimide, kanamycin and nalidixic acid for isolation and enhancement of pigment production of Pseudomonas aeruginosa in clinical samples.

A new selective agar medium (CKNA), containing cetrimide 0.3 g/l, kanamycin sulfate 50 mg/l, and nalidixic acid 5 mg/l, was developed for the isolation of Pseudomonas aeruginosa. It was compared to Nalidixic Acid Cetrimide agar (NAC), Pseudomonas Aeruginosa Selective Agar (PASA) and Pseudosel(TM) agar (CET) using 1,148 clinical specimens. The sensitivities rates of P. aeruginosa with CKNA, NAC, PASA, and CET were 88.2%, 81.3%, 79.2%, and 84.0%, respectively. The specificities of CKNA, NAC, PASA, and CET were 99.2%, 98.4%, 99.2%, and 99.7%, respectively.

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (2001). III. Secular changes in susceptibility].

The bacteria (Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Klebsiella spp. and Pseudomonas aeruginosa) isolated from patients diagnosed as urinary tract infections (UTIs) in 10 institutions in Japan were supplied between September and December, 2001. Then, the susceptibilities of these bacteria to various antimicrobial agents were examined, and the results were compared with those obtained between 1992 and 2000. Comparison was made by classifying strains isolated from patients into those in uncomplicated UTIs and those in complicated UTIs (including with or without indwelling catheter). The drug sensitivity of S. aureus in this year was comparable to those in up to the previous year, and S. aureus showed the best susceptibility to vancomycin (VCM). E. faecalis showed good susceptibility to ampicillin and imipenem, and the MIC90s were 2 micrograms/mL. The susceptibility of E. faecalis to VCM was also good. E. coli showed good susceptibility to the drugs except penicillins. Among cephems, the susceptibility to cefozopran (CZOP) was better (MIC90: < or = 0.125 microgram/mL). Just as the last report, the decreases in susceptibility of E. coli to quinolones were also observed in the patients with complicated UTIs. The susceptibility of Klebsiella spp. to all the test drugs did not significantly change in 2001 and was generally good but not to penicillins. Among cephems, Klebsiella spp. showed good susceptibility to flomoxef, cefpirome, cefixime, and CZOP with < or = 0.125 microgram/mL of MIC90s either in uncomplicated or complicated UTIs. Although the drug sensitivity of P. aeruginosa was generally low, the detection of the strains that showed good susceptibility to quinolones and carbapenems (MIC: < or = 0.125-2 micrograms/mL) were relatively frequent.

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (2000). I. Susceptibility distribution].

The bacterial strains isolated from patients diagnosed as having urinary tract infections (UTIs) in 10 institutions in Japan were supplied between the period of August 2000 and July 2001. Then, the susceptibilities of them to many kinds of antimicrobial agents were investigated. The number of them were 511 strains. The breakdown of these strains was Gram-positive bacteria as 29.0% and Gram-negative bacteria as 71.0%. Susceptibilities of these bacteria to antimicrobial agents were as follows; vancomycin (VCM), ampicillin (ABPC) and imipenem (IPM) showed strong activities against Enterococcus faecalis. No increase in low-susceptible strains of E. faecalis observed against these antimicrobial agents. VCM showed a strong activity against MRSA preventing growth of all strains with 1 microgram/ml. In addition, the activity of arbekacin (ABK) was strong with the MIC90 of 2 micrograms/ml against MRSA and prevented growth of all strains with 4 micrograms/ml. ABK showed a strong activity against Staphylococcus epidermidis preventing growth of all strains with 0.5 microgram/ml. ABPC, cefotiam (CTM) and cefozopran (CZOP) also showed a relatively strong activity against S. epidermidis (MIC90: 4 to 8 micrograms/ml). Against Escherichia coli, carbapenems showed high activities: meropenem (MEPM) prevented growth of all strains within 0.125 microgram/ml; IPM prevented growth of all strains with 0.25 microgram/ml. CZOP and CTM also showed strong activities against E. coli: MIC90 of CZOP was within 0.125 microgram/ml; MIC80 and MIC90 of CTM were 0.25 and 0.5 microgram/ml, respectively. Quinolone resistant E. coli was detected at frequency of 14.0%, which was significantly higher than that in the last year. Almost all drugs showed strong activities against Klebsiella pneumoniae and Proteus mirabilis, and MEPM prevented growth of all strains within 0.125 microgram/ml. Against Pseudomonas aeruginosa, almost drugs were not so active. The MIC90 of carbapenems and gentamicin (GM) were 16 micrograms/ml and those of all other drugs were more than 32 micrograms/ml. Against Serratia marcescens, the MIC90 of IPM and GM were the lowest value being 2 micrograms/ml, and that of MEPM was 4 micrograms/ml.

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (2000). II. Background of patients].

Five-hundred eighty eight bacterial strains isolated from 435 patients diagnosed as having urinary tract infections (UTIs) in 10 institutions in Japan were supplied between August 2000 and July 2001. Then, the clinical background of patients were investigated such as sex, age, and type of infections, infections and kind of bacteria, frequency of bacteria isolation by age and infections, bacteria and infections by timing of antibiotics administration, and bacteria and infections by surgical procedures. About the relationship between age and sex of patients and type of infections, the number of male patients aged less than 50 years was few, and complicated UTIs without indwelling catheter was the most frequent. In females, the number of patients aged less than 20 years was few. The majority of female patients aged 40 years and over had complicated UTIs while uncomplicated UTIs was most frequent in the patients being twenties. As for type of infections and kind of bacteria, Escherichia coli decreased when the infections became complicated, and pseudomonas aeruginosa increased when the infection became complicated. Enterococcus faecalis was isolated more frequently in complicated UTIs than in uncomplicated UTIs. Considering this result by age of patients, isolated frequency of E. coli was gradually decreased with aging in patients aged 20 years and over with uncomplicated UTIs or complicated UTIs without indwelling catheter. The isolated frequencies of Klebsiella spp., P. aeruginosa, and E. faecalis were high in the patients with complicated UTIs without indwelling catheter. In the patients aged 70 years and over with complicated UTIs with indwelling catheter, P. aeruginosa and E. faecalis were frequently isolated. As for type of causative organisms in UTIs before and after the administration of antibiotics, the isolation of bacteria was remarkably decreased after administration in the patients with uncomplicated UTIs and complicated UTIs without indwelling catheter. E. coli decreased after administration of antibiotics, and P. aeruginosa increased after administration in the patients with all types of infections. As for type of causative organisms in UTIs and surgical procedures, E. coli was frequently isolated in the patients without surgery in all types of infections, while P. aeruginosa was frequently isolated in the patients who underwent surgery. In uncomplicated UTIs, Proteus spp. and E. faecalis were frequently isolated in the patients with surgery. In complicated UTIs without indwelling catheter, Klebsiella spp. was frequently isolated in the patients without surgery and E. faecalis was frequently isolated in the patients with surgery. In complicated UTIs with indwelling catheter, most of organisms except P. aeruginosa and S. aureus were frequently isolated in the patients without surgery.

[Comparative studies on activities on antimicrobial agents against causative organisms isolated from patients with urinary tract infections (2000). III. Secular changes in susceptibility].

The bacteria (Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, Klebsiella spp. and Pseudomonas aeruginosa) isolated from patients diagnosed as having urinary tract infections (UTIs) in 10 institutions in Japan were supplied between August 2000 and July 2001. Then, the susceptibilities of these bacteria to various antimicrobial agents were examined, and the results were compared with those obtained between 1992 and 1999. Comparison was made by classifying strains isolated from patients into those in uncomplicated UTIs and those in complicated UTIs (including with or without indwelling catheter). E. faecalis showed good susceptibility to ampicillin (ABPC) and imipenem (IPM), and the MIC90s were 2 micrograms/ml. Also, E. faecalis showed good susceptibility to vancomycin (VCM). However, the MIC90, which was 2 micrograms/ml between 1992 and 1999, rose to 4 micrograms/ml in patients with complicated UTIs because the strains inhibited at 4 micrograms/ml increased more than before. The low susceptibility of S. aureus to arbekacin (ABK) in complicated UTIs, as shown in 1998 and 1999, recovered in 2000, and no strains inhibited at > or = 4 micrograms/ml were detected. E. coli showed good susceptibility to CTM (MIC90: 0.25-0.5 microgram/ml) and CZOP (MIC90: < or = 0.125 microgram/ml) and was not resistant to those. E. coli also showed good susceptibility to the other drugs except to penicillins. Decreases in susceptibility of E. coli to quinolones, ciprofloxacin (CPFX), and sparfloxacin (SPFX) were observed in the patients with complicated UTIs. The susceptibility of Klebsiella spp. to all drugs did not significantly change in 2000 and was generally good except to penicillins. Although the susceptibility of P. aeruginosa to carbapenems was notable, the MIC90 went up from 4 micrograms/ml to 16 micrograms/ml in complicated UTIs compared with those observed in the previous year.