Worldwide Lineages of Clinical Pneumococci in a Japanese Teaching Hospital Identified by DiversiLab System.

Pneumococcal Molecular Epidemiology Network (PMEN) clones are representatives of worldwide-spreading pathogens. DiversiLab system, a repetitive PCR system, has been proposed as a less labor-and time-intensive genotyping platform alternative to conventional methods. However, the utility and analysis parameters of DiversiLab for identifying worldwide lineages was not established. To evaluate and optimize the performance of DiversiLab for identifying worldwide pneumococcal lineages, we examined 245 consecutive isolates of clinical Streptococcus pneumoniae from all age-group patients at a teaching hospital in Japan. The capsular swelling reaction of all isolates yielded 24 different serotypes. Intensive visual observation (VO) of DiversiLab band pattern difference divided all isolates into 73 clusters. Multilocus sequence typing (MLST) of representative 73 isolates from each VO cluster yielded 51 different STs. Among them, PMEN-related lineages accounted for 63% (46/73). Although the serotype of PMEN-related isolates was identical to that of the original PMEN clone in 70% (32/46), CC156-related PMEN lineages, namely Greece(6B)-22 and Colombia(23F)-26, harbored various capsular types discordant to the original PMEN clones. Regarding automated analysis, genotyping by extended Jaccard (XJ) with a 75% similarity index cutoff (SIC) showed the highest correlation with serotyping (adjusted Rand's coefficient, 0.528). Elevating the SIC for XJ to 85% increased the discriminatory power sufficient for distinguishing two major PMEN-related isolates of Taiwan(19F)-14 and Netherlands(3)-31. These results demonstrated a potential utility of DiversiLab for identifying worldwide lineage of pneumococcus. An optimized parameters of automated analysis should be useful especially for comparison for reference strains by "identification" function of DiversiLab.

Incorrect diagnosis of Clostridium difficile infection in a university hospital in Japan.

Physicians often fail to suspect Clostridium difficile infection (CDI) and many microbiology laboratories use suboptimal diagnostic techniques. To estimate the extent of and reasons for incorrect diagnosis of CDI in Japan, we investigated toxigenic C. difficile isolated from all stool culture samples and clinical course. Over a 12-month period in 2010, all stool culture samples (n = 975) submitted from inpatients in a university hospital in Japan were cultured for C. difficile and routine microbiological testing was conducted. In total, 177 C. difficile isolates were recovered, and 127 isolates were toxigenic. Among the toxin-A-positive/toxin-B-positive isolates, 12 were also positive for the binary toxin gene. However, clinically important ribotypes, such as 027 and 078, were not identified. A total of 58 (45.7%) cases with toxigenic C. difficile had unformed stool, and the incidence CDI was 1.6 cases per 10,000 patient-days. Of these 58 cases, 40 were not diagnosed in routine testing due to a lack of clinical suspicion (24.1%, 14/58) or a negative C. difficile toxin assay result (44.8%, 26/58). A stool toxin assay was performed in 54 patients (78.2%, 54/69) who did not have unformed stool. The present study demonstrated that a significant number of CDI cases in Japan might be overlooked or misdiagnosed in clinical practice due to a lack of clinical suspicion and limitations of microbiological testing for CDI in Japan. Providing education to promote awareness of CDI among physicians is important to improve the accuracy of diagnosis in Japan.

Daptomycin susceptibility of 833 strains of Gram-positive cocci from a university hospital in Japan (2009-2011).

The aim of this study was to confirm the daptomycin (DAP) susceptibility of bacteria isolated before the launch of DAP in Japan. DAP showed good activity against all 833 isolates (MIC90 = 0.25-0.5 mg/L for staphylococci, 0.5-4 mg/L for enterococci, and 0.25-0.5 mg/L for streptococci). This is the first report of the in vitro activity of DAP against Gram-positive cocci, including methicillin-resistant Staphylococcus aureus and enterococci, isolated in Japan.

[Nationwide surveillance of parenteral antibiotics containing meropenem activities against clinically isolated strains in 2012].

The nationwide surveillance of antibacterial susceptibility to meropenem (MEPM) and other parenteral antibiotics against clinical isolates during 2012 in Japan was conducted. A total of 2985 strains including 955 strains of Gram-positive bacteria, 1782 strains of Gram-negative bacteria, and 248 strains of anaerobic bacteria obtained from 31 medical institutions were examined. The results were as follows; 1. MEPM was more active than the other carbapenem antibiotics tested against Gram-negative bacteria, especially against enterobacteriaceae and Haemophilus influenzae. MEPM was also active against most of the species tested in Gram-positive and anaerobic bacteria, except for multi-drug resistant strains including methicillin-resistant Staphylococcus aureus (MRSA). 2. Of all species tested, there were no species, which MIC90 of MEPM was more than 4-fold higher than those in our previous studies in 2009 or 2006. Therefore, the tendency to increase in antimicrobial resistance rates was not observed. 3. MEPM resistance against Pseudomonas aeruginosa was 17.8% (56/315 strains). Compared to our previous results, it was the lowest than that in 2006 and 2009. 4. Carbapenem-resistant Klebsiella pneumoniae, and multi-drug-resistant Acinetobacter species, which emerged in worldwide, were not observed. 5. The proportion of extended-spectrum beta-lactamase (ESBL) strains was 6.2% (59/951 strains) in enterobacteriaceae, which increased compared with that of our previous studies in 2009 or before. Whereas, the proportion of metallo-beta-lactamase strains was 1.6% (5/315 strains) in P. aeruginosa, which was stable. In conclusion, the results from this surveillance suggest that MEPM retains its potent and broad antibacterial activity and therefore is a clinically useful carbapenem for serious infections treatment at present, 17 years passed after available for commercial use in Japan.

Molecular characterization of extraintestinal Escherichia coli isolates in Japan: relationship between sequence types and mutation patterns of quinolone resistance-determining regions analyzed by pyrosequencing.

Infection from fluoroquinolone-resistant Enterobacteriaceae is an increasing health problem worldwide. In the present study, we developed a pyrosequencing-based high-throughput method for analyzing the nucleotide sequence of the quinolone resistance-determining regions (QRDRs) of gyrA and parC. By using this method, we successfully determined the QRDR sequences of 139 out of 140 clinical Escherichia coli isolates, 28% of which were nonsusceptible to ciprofloxacin. Sequence results obtained by the pyrosequencing method were in complete agreement with those obtained by the Sanger method. All fluoroquinolone-resistant isolates (n = 35; 25%) contained mutations leading to three or four amino acid substitutions in the QRDRs. In contrast, all isolates lacking a mutation in the QRDR (n = 81; 57%) were susceptible to ciprofloxacin, levofloxacin, and nalidixic acid. The qnr determinants, namely, the qnrA, qnrB, and qnrS genes, were not detected in the isolates, and the aac(6')-Ib-cr gene was detected in 2 (1.4%) of the isolates. Multilocus sequence typing of 34 randomly selected isolates revealed that sequence type 131 (ST131) (n = 7; 20%) is the most prevalent lineage and is significantly resistant to quinolones (P < 0.01). The genetic background of quinolone-susceptible isolates seemed more diverse, and interestingly, neighboring STs of ST131 in the phylogenetic tree were all susceptible to ciprofloxacin. In conclusion, our investigation reveals the relationship between fluoroquinolone resistance caused by mutations of QRDRs and the population structure of clinical extraintestinal E. coli isolates. This high-throughput method for analyzing QRDR mutations by pyrosequencing is a powerful tool for epidemiological studies of fluoroquinolone resistance in bacteria.

[In vitro susceptibilities to levofloxacin and various antibacterial agents of 12,866 clinical isolates obtained from 72 centers in 2010].

Postmarketing surveillance of levofloxacin (LVFX) has been conducted continuously since 1992. The present survey was performed to investigate in vitro susceptibility of recent clinical isolates in Japan to 30 selected antibacterial agents, focusing on fluoroquinolones (FQs). The common respiratory pathogens Streptococcus pyogenes, Streptococcus pneumoniae, Moraxella catarrhalis, and Haemophilus influenzae continue to show a high susceptibility to FQs. In contrast, widely-prevailing resistance to macrolides was markedly noted among S pneumoniae and S. pyogenes. Regarding H. influenzae, the prevalence of beta-lactamase-negative ampicillin-resistant isolates has been increasing year by year (25.8% in 2002, 40.0% in 2004, 50.1% in 2007, and 57.9% in 2010). Enterobacteriaceae showed high susceptibility to FQs, however, prevalence of LVFX-resistant Escherichia coli, including intermediate resistance, was 29.3%, showing an increase over time. Nevertheless, the increase in the prevalence of LVFX-resistant E. coli isolates has slowed since 2007 (8.2% in 2000, 11.8% in 2002, 18.8% in 2004, 26.2% in 2007, and 29.3% in 2010), suggesting the influence of LVFX 500 mg tablets since its approval in 2009. Another Enterobacteriaceae member, Klebsiella pneumoniae, showed low resistance to FQs, in contrast with E. coli. In methicillin-resistant Staphylococcus aureus (MRSA), the percentage of FQ-susceptible isolates was low, at 51.6% for susceptibility to sitafloxacin, and at only around 10% for susceptibility to other FQs. However, methicillin-susceptible S. aureus (MSSA) isolates were highly susceptible to FQs, with the percentage ranging from 88.5% to 99.1%. The prevalence of FQs-resistant isolates in methicillin-resistant coagulase-negative staphylococci was higher than that in methicillin-susceptible coagulase-negative staphylococci, although it was lower than the prevalence of FQ-resistance in MRSA. The prevalence of FQs-resistant Pseudomonas aeruginosa isolates derived from urinary tract infections (UTIs) was 15.4-21.3%, higher than the prevalence of 6.1-12.3% in P. aeruginosa isolates from respiratory tract infections (RTIs). While this trend was consistent with the results of previous surveillance, gradual decreases were noted in the prevalence of FQ-resistant P. aeruginosa isolates derived from UTIs. The prevalence of multidrug-resistant P. aeruginosa was 2.3% among isolates derived from UTIs and 0.3% among isolates from RTIs, a decrease from the results of 2007. Acinetobacter spp. showed high susceptibility to FQs. Imipenem-resistant Acinetobacter baumannii, which is currently an emerging issue, was detected at a prevalence of 2.4% (13 isolates). Neisseria gonorrhoeae showed a high resistance of 81.3-82.5%, to FQs. Ceftriaxone (CTRX) continued to show 100% susceptibility until 2007, but the present survey revealed the advent of resistance to CTRX in some clinical isolates. The result of the present survey indicated that although methicillin-resistant staphylococci, Enterococcus faecium, P. aeruginosa from UTIs, N. gonorrhoeae, and E. coli showed resistance of about 20% or more (19.5-89.2%) against the FQs which have been used clinically for over 17 years, the trends observed were similar to the results of previous surveillance. While FQ resistance has been prevailing in E. coli, E. coli still shows more than 70% susceptibility to FQs. The other bacterial species maintained high susceptibility rates of greater than 80%, against FQs.

Genotyping of skin and soft tissue infection (SSTI)-associated methicillin-resistant Staphylococcus aureus (MRSA) strains among outpatients in a teaching hospital in Japan: application of a phage-open reading frame typing (POT) kit.

We aimed to elucidate the current epidemiological features of outpatient skin and soft tissue infection (SSTI)-associated methicillin-resistant Staphylococcus aureus (MRSA) in Japan. Altogether, we evaluated the performance of a phage-open reading frame typing (POT) kit for genotyping these MRSA strains. We collected 57 MRSA strains from all outpatients with SSTIs attending a teaching hospital in Japan. Drug susceptibility measurement and genotyping including SCCmec typing, spa typing, multilocus sequence typing, pulsed-field gel electrophoresis, and commercial POT-kit were performed. The majority of strains (39 strains, 68 %) had the SCCmec-II element. Seventeen strains (30 %) with SCCmec-IV accounted for the second largest population. Strains with SCCmec-IV and SCCmec-V appeared multiclonal, and a predominance of Panton-Valentine leukocidin (PVL) gene-negative CC8/spa-CC008 strains, as well as the first isolate of an ST93 strain in Japan, was observed among them. Only one USA300 strain was identified. Strains with SCCmec-IV and SCCmec-V were significantly susceptible to antimicrobials. The PVL gene was found in 5 SCCmec-IV strains and 1 SCCmec-V strain. The POT-kit successfully predicted the SCCmec type in 54 strains (95 %), and typing by POT1 scores was highly concordant with SCCmec typing and spa typing. Moreover, three PVL-positive strains fell into a particular POT type (POT scores, 106-77-113). Simpson's index of the POT-kit was 0.977. In conclusion, the present study clarified the multiclonal nature of outpatient SSTI-associated MRSA in a teaching hospital in Japan. These data also underscore the utility of the POT-kit for non-outbreak surveillance through its simple platform consisting of two multiplex PCRs without sequencing.

[Nationwide surveillance of parenteral antibiotics containing meropenem activities against clinically isolated strains in 2009].

The antibacterial activity of meropenem (MEPM) and other parenteral antibiotics against clinical isolates of 2655 strains including 810 strains of Gram-positive bacteria, 1635 strains of Gram-negative bacteria, and 210 strains of anaerobic bacteria obtained from 30 medical institutions during 2009 was examined. The results were as follows; (1) MEPM was more active than the other carbapenem antibiotics tested against Gram-negative bacteria, especially against enterobacteriaceae and Haemophilus influenzae. MEPM was also active against most of the species tested in Gram-positive and anaerobic bacteria, except for multidrug resistant strains including methicillin-resistant Staphylococcus aureus (MRSA). (2) MEPM maintained potent and stable antibacterial activity against Pseudomonas aeruginosa. The proportion of MEPM-resistant strains to ciprofloxacin-resistant strains or imipenem-resistant strains were 53.1% and 58.0% respectively. (3) The proportion of extended-spectrum beta-lactamase (ESBL) strains was 3.1% (26 strains) in enterobacteriaceae. And the proportion of metallo-beta-lactamase strains was 2.0% (6 strains) in P. aeruginosa. (4) Of all species tested, there were no species except for Bacteroides fragilis group, which MIC90 of MEPM was more than 4-fold higher than those in our previous study. Therefore, there is almost no significant decrease in susceptibility of clinical isolates to meropenem. In conclusion, the results from this surveillance study suggest that MEPM retains its potent and broad antibacterial activity and therefore is a clinically useful carbapenem for serious infections treatment at present, 14 years passed after available for commercial use in Japan.

In vitro antibacterial activity of modithromycin, a novel 6,11-bridged bicyclolide, against respiratory pathogens, including macrolide-resistant Gram-positive cocci.

The in vitro activities of modithromycin against Gram-positive and -negative respiratory pathogens, including macrolide-resistant cocci with different resistance mechanisms, were compared with those of other macrolide and ketolide agents. MICs were determined by the broth microdilution method. All 595 test strains used in this study were isolated from Japanese medical facilities. The erm (ribosome methylase) and/or mef (efflux pump) gene, which correlated with resistance to erythromycin as well as clarithromycin and azithromycin, was found in 81.8%, 21.3%, and 23.2% of Streptococcus pneumoniae, Streptococcus pyogenes, and methicillin-susceptible Staphylococcus aureus (MSSA) strains, respectively. Modithromycin showed MIC(90)s of 0.125 µg/ml against these three cocci, including macrolide-resistant strains. In particular, the MIC of modithromycin against ermB-carrying S. pyogenes was ≥ 32-fold lower than that of telithromycin. The activities of modithromycin as well as telithromycin were little affected by the presence of mefA or mefE in both streptococci. Against Gram-negative pathogens, modithromycin showed MIC(90)s of 0.5, 8, and 0.031 µg/ml against Moraxella catarrhalis, Haemophilus influenzae, and Legionella spp., respectively. The MICs of modithromycin against M. catarrhalis and H. influenzae were higher than those of telithromycin and azithromycin. However, modithromycin showed the most potent anti-Legionella activity among the macrolide and ketolide agents tested. These results suggested that the bicyclolide agent modithromycin is a novel class of macrolides with improved antibacterial activity against Gram-positive cocci, including telithromycin-resistant streptococci and intracellular Gram-negative bacteria of the Legionella species.

[In vitro susceptibilities to levofloxacin and various antibacterial agents of 12,919 clinical isolates obtained from 72 centers in 2007].

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 Enterococcusfaecium 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.

[Nationwide surveillance of parenteral antibiotics containing meropenem activities against clinically isolated strains in 2006].

The antibacterial activity of meropenem (MEPM) and other parenteral antibiotics against clinical isolates of 876 strains of Gram-positive bacteria, 1764 strains of Gram-negative bacteria, and 198 strains of anaerobic bacteria obtained from 30 medical institutions during 2006 was measured. The results were as follows; 1. MEPM was more active than the other carbapenem antibiotics tested against Gram-negative bacteria, especially against enterobacteriaceae and Haemophilus influenzae. MEPM was also active against most of the species tested in Gram-positive and anaerobic bacteria, except for multi-drug resistant strains including methicillin-resistant Staphylococcus aureus. 2. As for Pseudomonas aeruginosa, all of the MEPM-resistant strains were resistant to imipenem (IPM). MEPM showed low cross-resistant rate both againt IPM-resistant P. aeruginosa (41.8%) and ciprofloxacin-resistant P. aeruginosa (33.3%). 3. The proportion of extended-spectrum beta-lactamase (ESBL) strains was 4.3% (6 strains) in Escherichia coli, 1.1% (1 strain) in Citrobacter freundii, 21.7% (5 strains) in Citrobacter koseri, 3.1% (4 strains) in Klebsiella pneumoniae, 3.3% (3 strains) in Enterobacter cloacae, 0.8% (1 strain) in Serratia marcescens, and 4.9% (2 strains) in Providencia spp. The proportion of metallo-beta-lactamase strains was 3.1% (10 strains) in P. aeruginosa. 4. Of all species tested, there were no species, which MIC90 of MEPM was more than 4-fold higher than those in our previous study. Therefore, there is almost no significant decrease in susceptibility of clinical isolates to meropenem. In conclusion, the results from this surveillance study suggest that MEPM retains its potent and broad antibacterial activity and therefore is a clinically useful carbapenem at present, 11 years after available for commercial use.

Identification of biochemically atypical Staphylococcus aureus clinical isolates with three automated identification systems.

Between January and April 2002, a total of 271 strains of Staphylococcus aureus were isolated from clinical specimens at Toho University Omori Hospital, Japan, including 201 (74.2 %) which were identified as meticillin-resistant S. aureus (MRSA). However, 34 (12.5 %) were biochemically atypical, because they did not produce acid on mannitol salt agar or did not agglutinate in Staphaurex testing but were categorized as MRSA by PCR analysis and by antibiotic susceptibility. Three automatic identification systems, AutoScan-4 (Dade Behring), BD Phoenix (Becton Dickinson) and Vitek 2 (bioMérieux), were evaluated by testing these atypical S. aureus isolates. The AutoScan-4 and Phoenix systems identified all 34 isolates as S. aureus. Without additional tests such as Staphaurex, observation of colony pigment and haemolysins on sheep blood agar, Vitek 2 identified only 16 isolates (47.1 %) as S. aureus with good or better confidence levels and misidentified one of the remaining isolates as Staphylococcus chromogenes. This study shows that it is possible to identify these physiologically atypical S. aureus isolates correctly by using the Phoenix and AutoScan-4 fully automatic identification systems.

[In-vitro susceptibilites to levofloxacin and various antibacterial agents of 18,639 clinical isolates obtained from 77 centers in 2004].

A total of 18,639 clinical isolates in 19 species collected from 77 centers during 2004 in Japan were tested for their susceptibility to fluoroquinolones (FQs) and other selected antibiotics. The common respiratory pathogens, Streptococcus pyogenes, Streptococcus pneumoniae, Moraxella catarrhalis and Haemophilus influenzae showed a high susceptible rate against FQs. The isolation rate of beta lactamase non-producing ampicillin-resistant H. influenzae was approximately three times as large as those of western countries. Most strains of Enterobacteriaceae were also susceptible to FQs. The resistance rate of Escherichia coli against FQs has however been rapidly increasing so far as we surveyed since 1994. The FQs-resistant rate in methicillin-resistant Staphylococcus aureus (MRSA) showed approximately 90% except for 36%. of sitafloxacin while FQs-resistant rate in methicillin-susceptible S. aureus (MSSA) was around 5%. The FQs-resistant rate of methicillin-resistant coagulase negative Staphylococci (MRCNS) was also higher than that of methicillin-susceptible coagulase negative Staphylococci (MSCNS), however, it was lower than that of MRSA. In Pseudomonas aeruginosa clinical isolates, 32-34% from UTI and 15-19% of from RTI was resistant to FQs. Acinetobacter spp. showed a high susceptibility to FQs. Although FQs-resistant Neisseria gonorrhoeae have not been increased in western countries, it is remarkably high in Japan. In this survey, isolates of approximately 85% was resistant to FQs.

[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.

[Nationwide surveillance of parenteral antibiotics containing meropenem activities against clinically isolated strains in 2004].

The antibacterial activity of meropenem (MEPM) and other parenteral antibiotics against clinical isolates of 907 strains of Gram-positive bacteria, 1790 strains of Gram-negative bacteria, and 192 strains of anaerobic bacteria obtained from 30 medical institutions during 2004 was measured. The results were as follows; 1. MIC90 of MEPM for almost all of enterobacteriaceae and Haemophilus influenzae were 4-fold to 32-fold lower than those of other carbapenems. MEPM was more active than other carbapenem antibiotics against Gram-negative bacteria, especially against enterobacteriaceae and H. influenzae. MEPM were active against most of the species tested in Gram-positive and anaerobic bacteria, except for multi-drug resistant strains including methicillin-resistant Staphylococcus aureus. 2. As for Pseudomonas aeruginosa, imipenem (IPM) showed high cross-resistant rate againt meropenem-resistant P. aeruginosa (87.9%). MEPM showed low cross-resistant rate both againt IPM-resistant P. aeruginosa (49.2%) and ciprofloxacin-resistant P. aeruginosa (38.0%). 3. The proportion of extended-spectrum beta-lactamase (ESBL) strains was 3.1% (4 strains) in Escherichia coli, 8.0% (2 strains) in Citrobacter koseri, 2.5% (3 strains) in Klebsiella pneumoniae, 2.5% (2 strains) in Enterobacter cloacae, 0.9% (1 strains) in Serratia marcescens, and 2.2% (2 strains) in Proteus mirabilis. The proportion of metallo-beta-lactamase strains was 1.6% (5 strains) in P. aeruginosa. 4. Of all species tested, Peptostreptococcus spp. was the only species, which MIC90 of MEPM was more than 4-fold higher than that in our previous study using clinical isolates during 2002 (0.25 microg/ml --> 1 microg/ml). Therefore, there is almost no siginificant decrease in susceptibility of clinical isolates to meropenem. In conclusion, the results from this surveillance study suggest that MEPM retains its potent and broad antibacterial activity and therefore is a clinically useful carbapenem at present, 9 years after available for commercial use.

[Nationwide surveillance of parenteral antibiotics containing meropenem activities against clinically isolated strains in 2002].

The antibacterial activity of meropenem (MEPM) and other parenteral antibiotics against clinical isolates of 899 strains of Gram-positive bacteria, 1500 strains of Gram-negative bacteria, and 158 strains of anaerobic bacteria obtained from 28 medical institutions during 2002 was measured. The results were as follows; 1. MEPM was more active than other carbapenem antibiotics against Gram-negative bacteria, especially against enterobacteriaceae and Haemophilus influenzae. MIC90 of MEPM against Pseudomonas aeruginosa was the lowest of the drugs tested. MEPM showed low cross-resistant rate against both imipenem-resistant P. aeruginosa and ciprofloxacin-resistant P. aeruginosa. MEPM was active against most of the species tested in Gram-positive and anaerobic bacteria, except for multi-drug resistant strains including methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant Staphylococcus epidermidis (MRSE). 2. The proportion of extended-spectrum beta-lactamase (ESBL) strains was 3.1% (4 strains) in Escherichia coli and 1.9% (2 strains) in Klebsiella pneumoniae. Carbapenems including MEPM were active against these ESBL strains. In conclusion, the results from this surveillance study suggest that MEPM retains its potent and broad antibacterial activity and therefore is a clinically useful carbapenem; at present, 7 years after available for commercial use.

[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.

Isolation of Helicobacter cinaedi from blood of an immunocompromised patient in Japan.

We report the isolation of Helicobacter cinaedi (previously called " Campylobacter-like organism") from the blood of an immunosuppressed Japanese patient receiving immunosuppressive therapy after renal transplantation. The identification of H. cinaedi was based on the findings of microscopic examinations, biochemical properties, and 16S rRNA gene nucleotide sequences. H. cinaedi bacteremia should be considered as one of the critical infectious diseases in immunocompromised patients, and the sequencing of 16S rRNA may be a useful method to confirm the identification of this organism.

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.

Long-term hospitalization during pregnancy is a risk factor for vitamin D deficiency in neonates.

In order to examine the effects of long-term hospitalization during pregnancy on vitamin D metabolism in pregnant women and neonates, we measured the serum 25-hydroxyvitamin D (25OHD) levels in pregnant women, as well as measuring 25OHD levels in cord blood and breast milk. In pregnant women hospitalized for longer than 1 month, the serum 25OHD levels were decreased at delivery compared with those in control subjects (10.9 +/- 2.6 ng/l vs 19.5 +/- 4.9 ng/l; P < 0.01). Although the levels of 25OHD in the cord blood were not significantly different between the long-term hospitalized and control pregnant women in this study (9.36 +/- 1.7 ng/l vs 11.1 +/- 3.0 ng/l), the 25OHD concentrations in the cord blood were significantly lower than the maternal levels in both groups; the ratios of the levels in cord blood to sera in the long-term hospitalized women and control subjects were 82.1% and 60.3%, respectively. Long maternal hospitalization does not always cause neonatal vitamin D deficiency, but could be one of its major risk factors. Therefore, sufficient sunlight exposure and intake of sufficient vitamin D are considered to be important to prevent vitamin D deficiency in long-term hospitalized pregnant women as well as their babies.