[Confirming the Utility of RAISUS Antifungal Susceptibility Testing by New-Software].

Clinical and Laboratory Standards Institute (CLSI) methods for susceptibility tests of yeast are used in Japan. On the other hand, the methods have some disadvantage; 1) reading at 24 and 48 h, 2) using unclear scale, approximately 50% inhibition, to determine MICs, 3) calculating trailing growth and paradoxical effects. These makes it difficult to test the susuceptibility for yeasts. Old software of RAISUS, Ver. 6.0 series, resolved problem 1) and 2) but did not resolve problem 3). Recently, new software of RAISUS, Ver. 7.0 series, resolved problem 3). We confirmed that using the new software made it clear whether all these issue were settled or not. Eighty-four Candida isolated from Aichi Medical University was used in this study. We compared the MICs obtained by using RAISUS antifungal susceptibility testing of yeasts RSMY1, RSMY1, with those obtained by using ASTY. The concordance rates (±four-fold of MICs) between the MICs obtained by using ASTY and RSMY1 with the new software were more than 90%, except for miconazole (MCZ). The rate of MCZ was low, but MICs obtained by using CLSI methods and Yeast-like Fungus DP 'EIKEN' methods, E-DP, showed equivalent MICs of RSMY1 using the new software. The frequency of skip effects on RSMY1 using the new software markedly decreased relative to RSMY1 using the old software. In case of showing trailing growth, the new software of RAISUS made it possible to choice the correct MICs and to put up the sign of trailing growth on the result screen. New software of RAISUS enhances its usability and the accuracy of MICs. Using automatic instrument to determine MICs is useful to obtain objective results easily.

Sensitivity surveillance of Pseudomonas aeruginosa isolates for several antibacterial agents in Chubu area (2013-2014).

We investigated the susceptibility to antibacterial agents of 186 clinical isolates of Pseudomonas aeruginosa isolated from medical facilities in Gifu, Aichi, Toyama, and Fukui prefectures from October 2013 to February 2014. MIC50/90 of piperacillin (PIPC), tazobactam/piperacillin (TAZ/PIPC), ceftazidime (CAZ), cefepime (CFPM), imipenem (IPM), meropenem (MEPM), doripenem (DRPM), aztreonam (AZT), ciprofloxacin (CPFX), levofloxacin (LVFX), amikacin (AMK) and colistin (CL) against P aeruginosa was 8/32, 4/32, 2/8, 2/16, 1/32, 0.5/8, 0.25/4, 8/32, 0.25/8, 0.5/16, 4/8 and 1/1pg/mLrespectively. Two strains of multidrug resistant P aeruginosa were isolated (1.1%). They were isolated from the respiratory tract, intra-abdominal, and urinary infection. The susceptible ratio against P aeruginosa derived from intra-abdominal infection for carbapenem was lower than those from respiratory tract and urinary infection. The susceptible ratio against P aeruginosa derived from urinary infection for penicillin, cephem, monobactam, and fluoroquinolone was lower than those from respiratory and intra-abdominal infection. It is meaningful to pay attention to the susceptibility to antibacterial agents in each clinical specimen from infected organ.

[Sensitivity surveillance of Streptococcus pneumoniae isolates for several antibacterial agents in Gifu and Aichi prefectures (2011-2012)].

We investigated the susceptibility to antibacterial agents, genotype of penicillin-binding protein (PBP) genes and macrolide resistant genes, and the serotypes against 270 strains of Streptococcus pneumoniae isolated from medical facilities in Gifu and Aichi prefectures between October 2011 and April 2012. These results were compared with those against S. pneumoniae isolated in 2008-2009 and 2010-2011. The number of gPSSP with 3 normal PBP genes, gPISP with 1 or 2 normal PBP genes and gPRSP with 3 abnormal genes isolated in 2011-2012 was 15 (5.6%), 162 (60.0%) and 93 (34.4%) strains, respectively. Compared with those isolated in 2008-2009 and 2010-2011, the numbers of gPRSP were decreasing. On the other hand, the isolates with no macrolide-resistant gene, only mefA, only ermB, and both mefA and ermB were 16 (5.9%), 75 (27.8%), 153 (56.7%) and 26 (9.6%). Compared with those isolated in 2008-2009 and 2010-2011, the numbers of isolates with ermB, which was usually associated with high-level resistance, were increasing. The prevalent pneumococcal serotypes in children were type 3 (14.4%), following by type 15 and 19F (9.3%). The coverages of 7-valent pneumococcal conjugate vaccine (PCV7) and 13-valent pneumococcal conjugate vaccine (PCV13) were calculated as 22.9% and 49.2%, respectively. The coverages of PCV7 and PCV13 in gPRSP isolated from children were 47.7% (21/44 strains) and 72.7% (32/44 strains). The MIC90 of each antibacterial agent was as follows; 0.125pg/mL for imipenem, panipenem and garenoxacin, 0.25 µg/mL for meropenem and doripenem, 0.5 µg/mL for cefditoren, moxifloxacin and tosufloxacin, 1 µg/mL for amoxicillin, clavulanic acid/amoxicillin, cefteram, cefcapene and ceftriaxone, 2 µg/mL for benzylpenicillin, ampicillin, sulbactam/ampicillin, piperacillin, tazobactam/piperacillin and levofloxacin, 4 µg/mL for cefdinir, flomoxef and pazufloxacin, 16 µg/mL for minocycline, > 64 µg/mL for clarithromycin and azithromycin, and these MIC90s were about the same as those in 2010-2011.

[Antimicrobial activity of several drugs against extended-spectrum beta-lactamase positive Enterobacteriaceae isolates in Gifu and Aichi prefecture].

We investigated the antimicrobial activity of several drugs against 131 extended-spectrum beta-lactamase (ESBL) positive clinical isolates in Gifu and Aichi prefecture from 2007 to 2011. Meropenem (MEPM) and doripenem (DRPM) gave the lowest MIC50 at 0.0313 microg/mL. MEPM gave the lowest MIC90 at 0.0625 microg/mL. According to the Clinical and Laboratory Standards Institute breakpoints, the susceptible rates of carbapenems, tazobactam/piperacillin (TAZ/PIPC) and cefmetazole (CMZ) were higher than 90%. The susceptible rates of MEPM, DRPM, imipenem (IPM), TAZ/PIPC and CMZ were 98.5%, 98.5%, 94.7%, 94.7% and 92.4%. We used the PCR method and identified the molecular types of the ESBL positive isolates. Seventy-two strains had CTX-M-9 group gene and CTX-M-9 group gene is the most frequently detected. Against the CTX-M-9 group gene harboring strains which were the most common in our investigation, the susceptible rates of TAZ/PIPC, MEPM, DRPM and IPM were 100%. It is suggested that not only carbapenems but also TAZ/PIPC and CMZ are useful against infections caused by ESBL positive isolates.

[Sensitivity surveillance of Streptococcus pneumoniae isolates for several antibacterial agents in Gifu and Aichi prefecture (2010-2011)].

We investigated genotype of penicillin-binding protein (PBP) genes and macrolide resistant genes, the serotypes and the susceptibility to antibacterial agents against 258 strains of Streptococcus pneumoniae isolated from medical facilities in Gifu and Aichi prefectures between January 2010 and March 2011. These results were compared with those against 377 strains of S. pneumoniae isolated in 2008-2009. The number of genotype penicillin-susceptible S. pneumoniae (gPSSP) with 3 normal PBP genes, genotype penicillin-intermediate S. pneumoniae (gPISP) with 1 or 2 normal PBP genes and genotype penicillin-resistant S. pneumoniae (gPRSP) with 3 abnormal genes was 11 (4.3%), 135 (52.3%) and 112 (43.4%) strains, respectively. The isolates with no macrolide-resistant gene, only mefA, only ermB, and both mefA and ermB were 17 (6.6%), 65 (25.2%), 143 (55.4%) and 33 (12.8%). The prevalent pneumococcal serotypes isolated from children were type 19F (18.2%), following by type 6A and 15 (11.7%). The potential coverage of pneumococcal conjugate vaccine (PCV7) was 43.8%. The prevalent pneumococcal serotypes isolated from adults were high in order of type 19F (12.8%), type 6A, 3 and 11 (10.3%), excepting non-typable strains (17.9%), and from elderly persons were type 6B (23.2%) and type 3 (13.4%). The MIC90 of each antibacterial agents was as follows; 0.0625 microg/mL for garenoxacin, 0.125 microg/mL for panipenem, 0.25 microg/mL for imipenem, doripenem, tosufloxacin, 0.5 microg/mL for cefditoren, meropenem, moxifloxacin, 1 microg/mL for amoxicillin, clavulanic acid/amoxicillin, cefteram, cefcapene, ceftriaxone, 2 microg/mL for benzylpenicillin, piperacillin, tazobactam/ piperacillin, pazufloxacin, levofloxacin, 4 microg/mL for cefdinir, flomoxef, 16 microg/mL for minocycline, > 64 microg/mL for clarithromycin, azithromycin and these MIC90s were about the same as those in 2008-2009.

[Multicenter surveillance of Pseudomonas aeruginosa strains for antimicrobials in Aichi prefecture in 2009].

We investigated the susceptibility to antimicrobials of 204 Pseudomonas aeruginosa strains isolated from 21 hospitals in Aichi prefecture from September to November 2009. MIC distributions of various antimicrobials were analyzed in terms of geographic region of isolation, patient status (outpatient or inpatient), and type of specimens that the strain was isolated from. The results were as follows. 1. Although more than 90% of strains were susceptible to all aminoglycosides and colistin, 80-90% of them were susceptible to beta-lactams and fluoroquinolones. MIC distributions of all antimicrobials measured were not significantly different between regions. 2. Only 1 strain (0.5%) was multi-drug resistant Pseudomonas aeruginosa (MDRP). Thirteen strains (6.4%) showed imipenem MIC > or = 16 microg/mL, and 16 strains (7.8%) showed ciprofloxacin MIC > or = 4 microg/mL. These strains tended to be more isolated from urine, respiratory tract specimens, or surgical specimens. 3. The MICs of tazobactam/piperacillin, panipenem, meropenem, doripenem, biapenem, sulbactam/cefoperazone, cefepime, and aztreonam were significantly higher in strains isolated from inpatients than in those from outpatients. MIC distributions of antimicrobials other than beta-lactams were not significantly different between situations where strains were isolated. 4. MIC distributions of piperacillin, all carbapenems, cefepime, gentamicin, and all fluoroquinolones were significantly different among samples from which strains were isolated. The strains isolated from blood showed lower MICs against all antimicrobials than those from other samples. No difference was found in MIC distributions when categorized according to bacteremic origin. The MICs were apparently elevated against beta-lactams, fluoroquinolones, and gentamicin in strains isolated from respiratory tract specimens, and against beta-lactams, and fluoroquinolones in strains isolated from urine. It was suggested that in P. aeruginosa surveillance, the results should be reported by stratifying with patient status, and type of specimens that the strain was isolated from and that regional surveillance should be useful with such stratification to establish antibiograms for empirical antimicrobial choice.

[Sensitivity surveillance of Streptococcus pneumoniae isolates for several antibacterial agents in Gifu and Aichi prefecture (2008-2009)].

We investigated the susceptibility to antibacterials, genotype of penicillin-binding protein (PBP) genes and macrolide resistant genes, and the serotypes against 377 strains of Streptococcus pneumoniae isolated from medical facilities in Gifu and Aichi prefectures between June 2008 and April 2009. These results were compared with those against 160 strains of S. pneumoniae isolated in 2004. Referring to CLSI (M100-S17), the overall incidence of penicillin-susceptible (PSSP), penicillin-intermediate (PISP) and penicillin-resistant (PRSP) S. pneumoniae was 143 (38%), 185 (49%) and 49 (13%) strains, respectively. PISP and PRSP were isolated higher in the material of nasal cavity and throat, and PRSP was isolated higher in the area of Chuno district. The number of gPSSP with 3 normal PBP genes, gPISP with 1 or 2 normal PBP genes and gPRSP with 3 abnormal genes was 23 (6.1%), 173 (46%) and 181 (48%) strains, respectively. The isolates with no macrolide-resistant gene, only mefA, only ermB, and both mefA and ermB were 28 (7.4%), 138 (37%), 166 (44%) and 45 (12%). The prevalent pneumococcal serotypes were type 19 (92 strains; 24%), following by type 23 (60 strains; 16%) and type 6 (56 strains; 15%). The 80% of pneumococcal serotypes of PRSP were serotype 19 and 6. The MIC90 of each antibacterial was as follows; 0.1 microg/mL for imipenem, panipenem and garenoxacin, 0.2 microg/mL for moxifloxacin, 0.39 microg/mL for meropenem and tosufloxacin, 0.78 microg/ mL for amoxicillin, clavulanic acid/amoxicillin, cefditoren and cefcapene, 1.56 microg/mL for benzylpenicillin, piperacillin, cefteram and levofloxacin, 3.13 microg/mL for cefotiam, flomoxef and pazufloxacin, 6.25 microg/mL for cefdinir, 12.5 microg/mL for norfloxacin and minocycline, > 100 microg/mL for clarithromycin, and these MIC90s were about the same as those in 2004.

[Sensitivity surveillance of Pseudomonas aeruginosa isolates for several antibacterial agents in Gifu and Aichi prefecture (2008)].

We investigated the susceptibility to antibacterial agents of 334 strains of Pseudomonas aeruginosa isolated from medical facilities in Gifu and Aichi prefectures from May to September 2008. For the beta-lactams, meropenem (MEPM) and doripenem (DRPM) gave the lowest MIC50 at 0.5 microg/mL, and tazobactam/piperacillin (TAZ/PIPC) gave the highest susceptible rate of the breakpoint by Clinical and Laboratory Standards Institute (CLSI) at 93.1%. For the quinolones, ciprofloxacin (CPFX) gave the lowest MIC50 at 0.25 microg/mL, followed by pazufloxacin (PZFX) at 0.5 microg/mL, and levofloxacin (LVFX) at 1 microg/mL, and susceptible rate was 76.0% for CPFX and 73.4% for LVFX. Susceptible rates to amikacin (AMK) and tobramycin (TOB) of aminoglycocides and colistin (CL) of polypeptides were 98.2%, 97.6% and 96.4%. In 334 strains, IMP-1 MBL producing P. aeruginosa was 1 strain, and the strain showed resistance to all antibacterial agents except AMK and CL used in this study. The strains isolated from urine were lower susceptible rate in comparison with those from sputum, notably the susceptible rate to CPFX from urine was less over 30% than those from sputum. Because the results of the susceptibility test against P. aeruginosa were different in each area, it is important for us to pay attention to the susceptibility to antibacterial agents and the emergence of resistance in the clinical strains through continuous susceptibility surveillance.

[Epidemiological analysis of Streptococcus pneumoniae in Gifu prefecture and the northern district of Aichi prefecture--2009].

High pathogenicity and drug resistance of Streptococcus pneumoniae are serious problem in clinical practice. Since 1999, we have conducted epidemiologic analyses of S. pneumoniae in Chubu district. We report the results of the analysis conducted in 2009. Three hundred and eight (308) S. pneumoniae isolates with a gene coding for autolysin lyt-A, which had been isolated from patients at 21 medical institutions in Gifu prefecture and the northern part of Aichi prefecture in 2009, were enrolled in this study. The strains were classified according to their drug resistance based on the presence of the pbp mutation, and examined for the presence of the two macrolide-resistance genes, ermB and mefA. Moreover, they were serotyped using type-specific antisera. The mean age of the patients from whom these S. pneumoniae strains were isolated, was 23.4 +/- 30.1 years old, and children aged 15 years old or less accounted for 66% of all the patients. Genotype penicillin-susceptible S. pneumoniae (gPSSP), genotype penicillin-intermediate S. pneumoniae (gPISP) and genotype penicillin-resistant S. pneumoniae (gPRSP) were 22 (7.1%), 131 (42.5%) and 155 (50.3%), respectively. The strains with mefA positive and ermB negative, mefA negative and ermB positive, and mefA positive and ermB positive were 80 (26.0%), 153 (49.7%), and 47 (15.3%), respectively. The MIC90 values of tebipenem (TBPM) and faropenem were 0.06 microg/mL and 0.5 microg/mL, respectively. TBPM showed the high bactericidal activity against gPRSP. In carbapenems, panipenem and biapenem exhibited higher bactericidal activities. Quinolone-resistant S. pneumoniae (QRSP) were isolated from 10 (3.2%). QRSP dominated 5 (7.9%) and 3 (1.5%) among the elderly (over 65 years old) and children, respectively. (As for the serotype, serotypes 6, 19 and 23 were 60 (19.5%), 62 (20.1%), and 44 (14.3%), respectively. Further epidemiologic studies on S. pneumoniae might be required also in the future, including the relationship between the serotype and drug resistance.

[Antibacterial susceptibility surveillance of Haemophilus influenzae isolated from pediatric patients in Gifu and Aichi prefectures (2009-2010)].

We investigated the susceptibility to antibacterial agents of 197 strains of Haemophilus influenzae isolated from pediatric patients at medical facilities in Gifu and Aichi prefectures between 2009 and 2010. Those strains were also examined for the mutations of ftsI coding for penicillin-binding protein 3, presence of bla TEM-1, serotype and beta-lactamase producing ability. Among the 197 strains, the most prevalent serotype was non-typeable (89.8%), followed by serotype b (8.1%), e (1.5%) and f (0.5%). Based on the susceptibility among the 197 strains to antibacterial agents, beta-lactamase nonproducing ampicillin-susceptible H. influenzae (BLNAS) accounted for 27.4%, beta-lactamase nonproducing ampicillin-resistant H. influenzae (BLNAR) for 62.4%, beta-lactamase producing ampicillin-resistant H. influenzae (BLPAR) for 6.1% and beta-lactamase producing amoxicillin/ clavulanic acid-resistant H. influenzae (BLPACR) for 4.1%. According to PCR-based genotyping, the strains were classified into 6 categories: gBLNAS, gLow-BLNAR, gBLNAR, gBLPAR, gBLPACR-I and gBLPACR-II. The incidences of each resistant class were 17.3% for gBLNAS, 6.6% for gLow-BLNAR, 66.0% for gBLNAR, 5.6% for gBLPAR and 4.6% for gBLPACR-II. The combined incidence of gLow-BLNAR and gBLNAR was 72.6%, which was higher than that of BLNAR (62.4%). The MIC90s of antibacterial agents against the 197 strains were as follows; 0.0156 microg/mL for tosufloxacin and garenoxacin, 0.0313 microg/mL for levofloxacin and pazufloxacin, 0.0625 microg/mL for norfloxacin, 0.25 microg/mL for tazobactam/piperacillin (TAZ/PIPC) and ceftriaxone, 0.5 microg/mL for TAZ/PIPC (1:8) and cefditoren, 1 microg/mL for piperacillin, cefteram, cefotaxime, meropenem, tebipenem and minocycline, 2 microg/mL for doripenem, 4 microg/mL for cefcapene, imipenem and azithromycin, 8 microg/mL for sulbactam/ampicillin, clavulanic acid/amoxicillin (1:2, CVA/AMPC) and cefdinir, 16 microg/mL for CVA/AMPC (1:14), flomoxef and clarithromycin, 32 microg/mL for ampicillin. Although there was no rapid increase in the antibacterial resistance, the prevalence of BLNAR was still over 50%. In order to ensure the appropriate chemotherapy, it is important to continue the surveillance of susceptibility among H. influenzae.

[Investigation on the identification accuracy for group B Streptococcus by automated identification system RAISUS].

Since we had experienced a case of misidentification for group B Streptococcus (GBS) (Streptococcus agalactiae) by automated identification system RAISUS, we have investigated the identification accuracy for GBS by automated identification system RAISUS system using our stock isolated of GBS. Among 31 strains including standard strain ATCC13813 of GBS, 30 strains were identified as GBS, while only 1 strain was misidentified as Streptococcus constellatus. We have needed 3 hours to identify 29 true GBS strains, while it has taken 6 hours for misidentified strain as S. constellatus. Since we have needed more than 4 hours for our misidentified strain of GBS, the tendency for identification time to become long has been recognized. Longer identification time might be associated with the misidentification. The improvement for galactose and glycerol tests of RAISUS by the manufacturer has resulted in better identification. As for the strains to be identified as S. constellatus by RAISUS, we might re-check it with other identification kits when there is higher clinical necessity.

[Epidemiological analysis of Streptococcus pneumoniae in Gifu prefecture].

Since antimicrobial resistance in Streptococcus pneumoniae become serious problem, we have conducted the epidemiological analysis of Streptococcus pneumoniae in Gifu prefecture. We have investigated the mutations of penicillin-binding protein (PBP) cording genes, the mutations of macrolide-resistant cording genes, and antimicrobial susceptibility using broth microdilution method, for 345 strains isolated from clinical specimens between May 2006 and July 2006 at 12 clinical facilities of 5 medical area. The ratio of penicillin-susceptible S. pneumoniae (gPSSP), penicillin-intermediate S. pneumoniae (gPISP), and penicillin-resistant S. pneumoniae (gPRSP), which were judged by molecular techniques, were 7.2%, 53.5%, and 39.4%, respectively. Only 1 gPSSP strain was isolated from children under three years old. There have been regional differences of the isolation rate of gPRSP between Gifu/Chuno area (55-60%) and Tono/Hida area (23-32%) in second- or third-medical facilities. The isolation rate of PBP mutation genes, pbp2x, pbp1a and pbp2b, were 92.8%, 52.5% and 53.3%, respectively. The isolation rate of macrolide-resistant cording genes, mefA only, ermB only, and both mefA and ermB, were 30%, 50% and 8%, respectively. The strains of S. pneumoniae with both mefA and ermB mutations, increased from 4% in 2002 to 8% in 2006. The antimicrobial susceptibility of S. pneumoniae to penicillin G (PCG) showed two peaks around 0.03 and 1 microg/mL, and 89% of S. pneumoniae with minimum inhibitory concentration (MIC) value 1 microg/mL was gPRSP. The MIC values of PCG against 69% strains of gPRSP distributed between 0.25 and 1 microg/mL. There have been the decreased tendency for the differences among medical facilities in penicillin resistant strains. Although cefditoren showed the most effective antimicrobial activity in oral cephems tested, there have been the strains with MIC value of over 1 microg/mL. The MIC90 of panipenem was 0.125 microg/mL, which was the best antimicrobial activity in carbapenems. The resistant rates of clarithromycin and azithromycin were 85% and 84%, respectively. The strains with the gene mutation of ermB have showed resistant to clindamycin. The MIC90 of tosufloxacin was 0.25 microg/mL, which was the best antimicrobial activity in quinolones. We have detected 4 levofloxacin highly resistant S. pneumoniae, of which MIC value was over 32 microg/mL. Also, we have encountered the episode of the spread of S. pneumoniae in one family, which was clarified by scientific approach.

[Antibiotic susceptibility of blood-borne Streptococcus pneumoniae and efficacy assessment of respiratory quinolones using Monte Carlo simulation].

We analyzed Streptococcus pneumoniae isolates from the bloodstream between April 2005 and February 2007. We analyzed isolates of 28 strains from medical facilities in Gifu prefecture to determine antibiotic susceptibility, genotype of penicillin-binding protein (PBP) genes and macrolide resistant genes. We also assessed the efficacy of respiratory quinolones using Monte Carlo simulation. Garenoxacin (GRNX) and moxifloxacin (MFLX) showed the lowest MIC90 value of 0.125 microg/mL, followed by MIC90 of imipenem (IPM) of 0.25 microg/mL and tosufloxacin (TFLX), MIC90 of meropenem (MEPM) and vancomycin (VCM) of 0.5 microg/mL. Twenty-two strains possessed at least one mutation in PBP-encoding genes pbp1a, pbp2x or pbp2b and seven strains possessed all three mutant alleles. Twenty-two strains possessed either of macrolide resistant genes ermB or mefA, and one strain possessed both. On efficacy assessment, we calculated the probability of target attainment for free-drug area under the curve (fAUC)/MIC ratio (fAUC/MIC). GRNX and MFLX showed a probability of 90% or more at fAUC/MIC of 30 and 125, each considered effective against Gram-positive bacteria and suppression of resistance development, furthermore, GRNX showed a probability of 89.7% at fAUC/MIC of 250.

First report of acute cholecystitis with sepsis caused by Cellulomonas denverensis.

Cellulomonas denverensis is a small and thin gram-positive rod-shaped bacterium that was proposed as a new species in 2005. Here we report a female case of acute cholecystitis and sepsis in which C. denverensis was determined to be causative.

[Sensitivity surveillance of streptococci isolates for several antibiotics in Gifu prefecture (2005-2007)].

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 0.0078 microg/mL, followed by cefditoren and cefcapene at 0.0156 microg/mL and penicillin G, amoxicillin and meropenem at 0.0313 microg/mL. For Group B streptococci, cefteram, cefditoren, cefcapene and imipenem gave the lowest MIC90 at 0.0313 microg/mL, followed by penicillin G and meropenem at 0.0625 microg/mL and amoxicillin at 0.125 microg/mL. For Group G streptococci, cefteram and imipenem gave the lowest MIC90 at 0.0078 microg/mL, followed by penicillin G, cefditoren, cefcapene and meropenem at 0.0156 microg/mL and amoxicillin at 0.0313 microg/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 beta-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.

[Sensitivity surveillance of Haemophilus influenzae isolates for several antibiotics in Gifu Prefecture (2006)].

We investigated the susceptibility to antibacterials of 194 strains of Haemophilus influenzae isolated from medical facilities in Gifu prefecture between 2005 and 2006, and compared these results with those of 280 strains of H. influenzae isolated between 1999 and 2000. Additionally, the strains that had been separated between 2005 and 2006 were examined for beta-lactamase (BL) production, the mutation of ftsI gene coding for PBP3, the bla gene coding for TEM type of BL and the serotype. Referring to the CLSI breakpoint, H. influenzae strains were classified into the following categories: (1) beta-lactamase-negative ampicillin-susceptible (BLNAS) strains, which showed BL negative, ampicillin (ABPC) and ampicillin/sulbactam (ABPC/SBT)-MIC < or = microg/ml, (2) beta-lactamase producing ampicillin-resistant (BLPAR) strains, which showed BL producing and ABPC/SBT-MIC < or =2 microg/ml, (3) beta-lactamase-negative ampicillin-resistant (BLNAR) strains, which showed BL negative, ABPC and ABPC/SBT-MIC > or =2 microg/ml, (4) beta-lactamase-producing amoxicillin/clavulanic acid-resistant (BLPACR) strains, which showed BL producing and ABPC/SBT-MIC > or =4 microg/ml. The prevalence of each resistance class were 71.8% for BLNAS, 7.9% for BLPAR, 19.6% for BLNAR and 0.7% for BLPACR in strains isolated between 1999 and 2000. But they were 38.1% for BLNAS, 4.6% for BLPAR, 54.6% for BLNAR and 2.6% for BLPACR in strains isolated between 2005 and 2006, indicating that the percentage of BLNAS and BLPAR decreased and that of BLNAR and BLPACR increased from 1999-2000 to 2005-2006. On the basis of ftsI substitutions and having bla gene, the strains isolated between 2005 and 2006 were classified into the following distribution: 24.2% for gBLNAS, 4.1% for gBLPAR, 10.8% for gLow-BLNAR, 57.7% for gBLNAR, and 3.1% for gBLPACR-II. Ratio of BLNAR belonging to gBLNAR and gLow-BLNAR based on the ftsI substitutions and having bla gene was higher than that based on the susceptibility pattern. The MIC50 and MIC90 for those strains isolated between 2005 and 2006 were as follows; 0.0039, 0.0156 microg/ml for garenoxacin, 0.0078, 0.0156 microg/ml for tosufloxacin and ciprofloxacin, 0.0156, 0.0313 microg/ml for levofloxacin, 0.0313, 0.0625 microg/ml for norfloxacin, 0.0625, 0.25 microg/ml for piperacillin/ tazobactam, 0.0625, 0.5 microg/ml for piperacillin, 0.125, 0.25 microg/ml for ceftriaxone and cefditoren, 0.5, 1 microg/ml for cefteram, chloramphenicol and tetracycline, 0.5, 2 microg/ml for cefotaxime, 2, 8 microg/ml for ampicillin, ampicillin/sulbactam and cefdinir. In comparison with the values for the strains isolated between 1999 and 2000, the MIC50s of beta-lactam for the strains isolated between 2005 and 2006 increased over 4 times.

[The antibacterial activity of fluoroquinolones against gram-negative bacteria isolated from Gifu Prefecture (2005)].

We investigated the susceptibility to 6 fluoroquinolones against 433 strains of Gram-negative bacteria isolated from 6 medical facilities in Gifu prefecture between January and September in 2005, determined by the agar dilution methods in according with the Japan Society of Chemotherapy. We also investigated the correlation between the degree of resistance to fluoroquinolones and the amino acid substitutions in the quinolone resistance-determining region (QRDR). The tested clinical isolates were as follows, Salmonella spp.; 17 strains, Escherichia coli; 112 strains Citrobacter freundii; 35 strains, Enterobacter cloacae; 31 strains, Klebsiella pneumoniae; 73 strains, Proteus spp.; 18 strains, Providencia spp.; 3 strains, Morganella morganii; 14 strains, Serratia marcescens; 27 strains and Pseudomonas aeruginosa; 103 strains. The number of the strains resistant to ciprofloxacin (CPFX) (MIC > or = 6.25 microg/mL) was twenty (E. coli; 14 strains, E. cloacae; I strain, Proteus spp.; 2 strains and P. aeruginosa; 3 strains). Among these strains, 12 strain (E. coli; 11 strains and E. cloacae; 1 strain) were highly resistant to CPFX (MIC > or =25 microg/mL). The E. coli strains highly resistant to CPFX had the multiple amino acid mutations in QRDR of ParC an GyrA. However in other strains, there was no strains possessing multiple mutations in both ParC and GyrA.

[Multicenter-evaluation of optimal cell density to determine antimicrobial susceptibility for Haemophilus influenzae by the automated RAISUS system when the early-harvested bacterial cells were used].

The fully automated microbial system, RAISUS (Nissui Pharmaceutical, Tokyo, Japan) can provide antimicrobial susceptibility test results for the isolates of Haemophilus influenzae. It is known that viable cell concentrations (colony forming unit/ml) of H. influenzae significantly vary depending on the incubation period. For the rapid reporting of antimicrobial susceptibility test results, we evaluated optimal cell density when we prepared the cell suspension using the early-harvested (6 hour incubation) cells for RAISUS. A total of 180 clinical isolates, comprising of 33 ampicillin-susceptible isolates, 114 beta-lactamase negative but ampicillin-resistant isolates and 33 beta-lactamase positive and amoxicillin/clavulanic acid susceptible or -resistant isolates, were included. All the isolates were genetically defined according to the detection of TEM gene and specific mutation (s) in fts I gene. The isolates were incubated on chocolate agar plates for 6 hours, and then the cell suspensions were prepared and adjusted to 0.5, 0.25 and 0.125 McFarland standards through serially dilutions. The respective cell suspensions were tested by the RAISUS AST panels. The % agreements between RAISUS and Clinical and Laboratory Standards Institute standard microdilutions in ampicillin category interpretations were 66.7%(McFarland 0.5), 77.8% (McFarland 0.25) and 83.9%(McFarland 0.125). When the McFarland 0.125 cell suspensions were inoculated, the majority of discrep ant interpretations were minor errors (15.0%) and the occurrence of major error was 3.4%. There was no very major error throughout the study. Essential agreement in MIC determinations (with or within +/- 1 doubling dilution) for 11 beta-lactam antimicrobial agents tested improved to 95.2% by McFarland 0.125 when compared to 77.4% by McFarland 0.5. It was also demonstrated that the viable cell concentrations prepared from 6 hour incubation cultures were 2.5 to 6.5 times higher than those from 22 hour-incubations. With these results, it can be concluded that the early harvested cell suspension of H. influenzae is applicable to RAISUS antimicrobial susceptibility test with lower cell density (McFarland 0.125). With this adjustment, the antimicrobial susceptibility test for H. influenzae will be completed by RAISUS within 26 hours after primary isolation.

Clinical and bacteriological evaluation of the efficacy of piperacillin in children with pneumonia.

We aimed to prospectively evaluate the clinical and bacteriological effects of piperacillin in children with pneumonia. Twenty-eight patients (6 months to 5 years of age) with pneumonia were treated with piperacillin. In the same period, 95 strains of Haemophilus influenzae and 41 strains of Streptococcus pneumoniae were isolated in our department and the minimum inhibitory concentration (MIC) of piperacillin was determined. The clinical efficacy of piperacillin was excellent in 4 cases, good in 23, and fair in 1; the response rate was 96.4% (27/28). Among the isolates from our department, there were 4 strains (9.8%) of penicillin-susceptible S. pneumoniae (PSSP), 32 strains (78.0%) of penicillin-intermediate-resistant S. pneumoniae (PISP), and 5 strains (12.2%) of penicillin-resistant S. pneumoniae (PRSP). Against S. pneumoniae, the MIC50 and MIC90 for piperacillin were 0.5 microg/ml and 2 microg/ml, respectively. Panipenem showed the best results, followed by piperacillin, ampicillin, and flomoxef. Among the isolates from our department, there were 51 strains (53.7%) of beta-lactamase-negative ampicillin-susceptible H. influenzae, 42 strains (44.2%) of beta-lactamase-negative ampicillin-resistant H. influenzae, 1 strain (1.1%) of beta-lactamase-positive ampicillin-resistant H. influenzae, and 1 strain (1.1%) of beta-lactamase-positive amoxicillin-clavulanic acid-resistant H. influenzae. The MIC50 and MIC90 for piperacillin against H. influenzae were 0.0625 microg/ml and 0.125 microg/ml, respectively. Tazobactam/piperacillin and piperacillin showed the best results, followed by panipenem, ampicillin, and flomoxef. Piperacillin proved to be very useful for the treatment of pneumonia in children.

[Surveillance on Pseudomonas aeruginosa isolated in Gifu prefecture (2004)].

We analyzed Pseudomonas aeruginosa isolates in Gifu prefecture between September and October 2004. We conducted antimicrobial susceptibility test for 266 strains isolated from 8 medical institutes and 1 clinical laboratory, based on broth microdilution method. The MIC50 and MIC90 of piperacillin, amikacin, imipenem, and ciprofloxacin were 4 and 64, 4 and 8, 1 and 16, 0.25 and 8 microg/mL, respectively. The strains isolated from urine had higher MIC level in comparison with from sputum, which was remarkable in penicillins, cephalosporins and fluoroquinolones. We isolated 7 strains of multi-drug resistant Pseudomonas aeruginosa (MDRP), in which 3 strains showed under 16 microg/mL in MIC against anti-MRSA (methicillin-resistant Staphylococcus aureus) drug arbekacin. Continuous surveillance would be needed for antimicrobial resistance on P. aeruginosa in Gifu prefecture.