Regional outbreak of CTX-M-2 ß-lactamase-producing Proteus mirabilis in Japan.

Proteus mirabilis is a common cause of urinary tract infection. Wild-type P. mirabilis strains are usually susceptible to penicillins and cephalosporins, but occurrences of P. mirabilis producing extended-spectrum ß-lactamases (ESBLs) have been recently reported. Here, we surveyed the prevalence of cefotaxime resistance among P. mirabilis strains at seven different hospitals in Kanagawa Prefecture, Japan, and investigated their molecular epidemiology to explain the mechanism of their spread. The prevalence of cefotaxime resistance among P. mirabilis increased annually, from 10.1 % in 1998 to 23.1 % in 2003, and increased drastically in 2004, exceeding 40 %. We collected 105 consecutive and non-duplicate cefotaxime-resistant P. mirabilis isolates (MIC 16 to >256 µg ml(-1)) from these hospitals from June 2004 to May 2005 and characterized their profile. PCR and sequence analysis revealed that all resistant strains produced exclusively CTX-M-2 ß-lactamase. PFGE analysis identified 47 banding patterns with 83 % or greater similarity. These results indicated that a regional outbreak of P. mirabilis producing CTX-M-2 ß-lactamase has occurred in Japan and suggest that the epidemic spread occurred within and across hospitals and communities by extended clonal strains. Plasmid analysis revealed that 44.8 % of plasmids harboured by bla(CTX-M-2) isolates had common profiles, encoding ISEcp1, IS26 and Int1, and belonged to incompatibility group T. Spread of the resistant isolates in Japan resulted from dissemination of narrow-host-range plasmids of the IncT group encoding bla(CTX-M-2). These findings indicate the rapidly developing problem of treating the species to prevent dissemination of ESBL producers.

Antimicrobial susceptibility of respiratory tract pathogens in Japan during PROTEKT years 1-5 (1999-2004).

Susceptibility to a range of antimicrobial agents was determined among isolates of Streptococcus pneumoniae, Streptococcus pyogenes, and Haemophilus influenzae collected in 12 centers throughout Japan during years 1-5 (the respiratory seasons of 1999-2004) of the longitudinal Prospective Resistant Organism Tracking and Epidemiology for the Ketolide Telithromycin study. The most frequent source of isolates of S. pneumoniae was from patients with community-acquired pneumonia (CAP) (25.3%). Reduced susceptibility to penicillin or erythromycin resistance was common among S. pneumoniae isolates (30.9-44.5% and 77.2-81.9%, respectively). The macrolide MIC(50) for S. pneumoniae was >or=128 microg/ml (azithromycin and erythromycin) and >or=64 microg/ml (clarithromycin). The erm(B) genotype accounted for the most erythromycin-resistant isolates in each study year. H. influenzae isolates were most commonly derived from patients with CAP (26.2%). The proportion of H. influenzae isolates that were beta-lactamase positive ranged between 4.3% and 9.7%. The prevalence of beta-lactamase-negative ampicillin-resistant isolates increased from 0.4% to 2.6% between years 1 and 4 then to 19.7% in year 5. S. pyogenes isolates were highly susceptible to most antimicrobial agents except macrolides and tetracycline. Telithromycin was highly active against all three pathogens examined throughout the study.

[Evaluation of antigen diagnostic kit in group A streptococcus mass infection].

We report a Food-borne group A streptococcus epidemic at Kitasato University campus on July 30 and 31, 2005, believed caused by lunch. A current mass group A streptococcus infection differing from the food-borne epidemic above occurred at Kitasato University East Hospital, also believed caused by lunch. Group A streptococcus was detected using a prompt diagnostic kit and bacterial culture from 116 clinical specimens taken from 116 patients with group A streptococcus pharyngitis at Kitasato University East Hospital on August 5, 2005. To investigate the utility of immunochromatographic detection of group A streptococcus antigen, 116 clinical specimens obtained from pharyngeal membranes by swab were examined using a prompt diagnostic kit for group A streptococcus (ImmunoCard STAT! STREP A TEST) and conventional bacterial culture. Group A streptococcus positivity differed between the two methods. Fourteen patients were found to be positive by the prompt diagnostic kit and 23 by bacterial culture. Four patients showing 1.0 x 10(6) cfu/mL estimated by the culture were difficult to diagnose with the prompt diagnostic kit,even though the detection sensitivity of this kit was 1.0 x 10(6) cfu/mL or more. Conventional bacterial culture should therefore be used in addition to the prompt diagnostic kit to detect group A streptococcus, especially in pharyngeal samples obtained from patients with pharyngitis.

Study of nasopharyngeal bacterial flora. Variations in nasopharyngeal bacterial flora in schoolchildren and adults when administered antimicrobial agents.

Changes in nasopharyngeal bacterial flora in adults with acute upper respiratory tract infection on administration of antimicrobial agents were investigated, and how these changes contrasted with those in children. Many patients with acute sinusitis due to allergies, and patients with malignancy and diabetes mellitus were included in the investigation. The detection rates of Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis, the major bacteria of acute otitis media (AOM), were 22%, 10%, and 7% respectively, which were significantly lower than those for children. Gram stain examination of nasopharyngeal swab samples showed a significant relation between leukocyte infiltration and the detection amount of S. pneumoniae (P = 0.0086). A significant relation (P = 0.0134) was also observed when H. influenzae was simultaneously detected. No significant change in the three major AOM bacteria present in nasopharyngeal bacterial flora after administration of antimicrobial agents was observed. However, all S. pneumoniae and H. influenzae detected after antimicrobial agent administration had the beta-lactam-resistance gene. It was observed that a significant improvement in leukocyte infiltration occurred 6 to 10 days after antimicrobial agent administration. In contrast, a significant improvement in children was observed at 2 to 5 days. In the adult subjects, this improvement was probably due to spontaneous remission rather than the effect of the antimicrobial agents. Although investigation of the long-term administration of antimicrobial agents was also conducted, its benefits for the patients were not elucidated.

[Comparison of antimicrobial and bactericidal activities and postantibiotic effects of macrolides antibiotics against clinical isolates, and examination of shape alteration by scanning electron microscope].

We examined antibacterial activities of 4 kinds of macrolides (MLs), erythromycin (EM), clarithromycin (CAM), azithromycin (AZM) and rokitamycin (RKM), against 4 bacterial species of clinical strains isolated in 2004. Bacterial isolates used were 51 strains of methicillin-susceptible Staphylococcus aureus (MSSA), 20 of Streptococcus pyogenes, 68 of Streptococcus agalactiae, and 120 of Streptococcus pneumoniae. Macrolide resistance genes, ermB and mefE, in macrolide-resistant S. pyogenes and S. agalactiae, and all of pneumococci were analyzed by PCR. Antimicrobial activities against macrolide-susceptible MSSA of EM and CAM, were more potent than those of RKM. By contrast, against S. pneumoniae, RKM was more effective than EM, CAM and AZM. Against S. pyogenes and S. agalactiae, 4 antibiotics showed similar antimicrobial activities. Twelve, 1 and 2 strains of MSSA, S. pyogenes and S. agalactiae, respectively, were resistant to EM, CAM and AZM, whereas RKM was active to almost, but not quite, of them. Among 120 strains of S. pneumoniae, 76 (63.3%) were resistant to EM (MIC; > or = 0.5 microg/mL), and 23, 15 and 28 strains were highly resistant (MIC; > 128 microg/mL) to EM, CAM and AZM, respectively. By contrast, for RKM, there were far fewer resistant strains, and there was no highly resistant strain. PCR analyses of macrolide-resistant genes revealed that 1 resistant strain of S. pyogenes and 2 of S. agalactiae carried mefE and ermB, respectively. In the case of S. pneumoniae, 59, 19 and 5 strains, respectively, carried ermB, mefE and both ermB and mefe. We also studied about bactericidal activities and postantibiotic effects (PAE) of MLs using macrolide-susceptible, and ermB- and mefE-carrying S. pneumoniae, and observed morphological alterations of the strains treated with the drugs by a scanning electron microscope. It was demonstrated that RKM had superior bactericidal activities and PAE than other 3 drugs, and potent destructive effects to all of 3 strains.

Resistance to gram-negative organisms due to high-level expression of plasmid-encoded ampC beta-lactamase blaCMY-4 promoted by insertion sequence ISEcp1.

A Klebsiella pneumoniae strain, KU6500, which showed resistance to extended-spectrum beta-lactams and produced the plasmid-encoded AmpC beta-lactamase CMY-4, was identified from clinical isolates in Japan. The aim of this study was to identify the mechanism of the high-level expression of blaCMY-4. Sequence analysis indicated that the promoter element of Citrobacter freundii was conserved, but the insertion sequence ISEcp1 coding with the putative promoter element, was inserted into the AmpR binding site. We determined the influence of the promoter on blaCMY-4 expression and beta-lactam resistance. Two recombinant plasmids containing the entire blaCMY-4 gene, with or without the ISEcp1-mediated promoter sequences, were constructed and named pMWampC and pMWISEcp1, respectively. Escherichia coli DH5alpha (pMWISEcp1) was resistant to almost all beta-lactams tested and E. coli DH5alpha (pMWampC) was susceptible to all, except for cephalothin. In addition, the activity of each promoter was measured by subcloning the element into a promoterless luciferase plasmid pGL3-Basic vector. The expression of the putative promoter of ISEcp1 was 18.9-fold higher than that of C. freundii. These results suggest that the putative promoter element of ISEcp1 is necessary for the high-level expression of blaCMY-4 to confer resistance to extended-spectrum cephalosporins.

Macrolide antibiotics promote the LPS-induced upregulation of prostaglandin E receptor EP2 and thus attenuate macrolide suppression of IL-6 production.

We studied the influence of the inhibitory effect of clarithromycin (CAM) and erythromycin (EM) on the production of macrophage inflammatory protein (MIP)-2, interleukin-6 (IL-6), and prostaglandin E(2) (PGE(2)), as well as PGE(2) receptor (EP(2)) expression, by LPS-stimulated RAW264.7 cells. Production of IL-6 was significantly decreased by treatment with CAM or EM in a dose-dependent manner, but the inhibitory effect of CAM was significantly weaker than that of EM. In contrast, the production of MIP-2 and PGE(2) was inhibited to the same extent by CAM and EM. LPS induced the expression of EP(2) mRNA and its expression was promoted further by treatment with CAM or EM. In particular, CAM significantly upregulated EP(2) mRNA expression compared with that after stimulation by LPS alone. After treatment with a nonselective cyclooxygenase (COX) inhibitor (indomethacin), a selective COX-2 inhibitor (NS398), or an EP(2)/EP(4) receptor antagonist (AH6809), the inhibitory effect of CAM and EM on LPS-induced IL-6 production was equalized. These results indicate that macrolide antibiotics upregulate the expression of EP(2), which then attenuates the suppressive effect on IL-6 production of these antibiotics, suggesting that these drugs have a variable anti-inflammatory effect that could influence host defenses.

The suppressive effect of Mekabu fucoidan on an attachment of Cryptosporidium parvum oocysts to the intestinal epithelial cells in neonatal mice.

The present study was done to investigate the effects of fucoidan and de-sulfated fucoidan isolated from the sporophyll of Undaria pinnatifida on the C. parvum adhesion to the cultured human intestinal cells and on the C. parvum infection in neonatal mice. The C. parvum adhesion to human Intestinal 407 cells was significantly suppressed by a low dose (1 micro g/ml) of Mekabu fucoidan (1 micro g/ml) (approx. 20.5 oocysts, p<0.0001), but not by de-sulfated fucoidan (approx. 138.2 oocysts), as compared with that (approx. 121.0 oocysts) of phosphate-buffered saline (PBS). The in vivo experiments presented here revealed that C. parvum oocysts in the fucoidan-treated mice was reduced nearly one fifth (approx. 5.4x10(4) oocysts, p<0.02) of the total number of oocysts (approx. 3.0x10(5)) in mice treated with PBS, but no significant effect of de-sulfated fucoidan was observed. These results show that (i) fucoidan effectively inhibits the growth of C. parvum in mice; and (ii) the ester sulfate of fucoidan is an active site to prevent the adhesion of C. parvum to the intestinal epithelial cells. Finally, we concluded that fucoidan might inhibit cryptosporidiosis through the direct binding of fucoidan to the C. parvum-derived functional mediators in the intestinal epithelial cells in neonatal mice.

[Distribution of Clostridium tetani in topsoil from Sagamihara, central Japan].

Despite reports of Clostridium tetani being isolated from soil in Kanazawa, Okinawa, and Tokyo, Japan, little has been studied about C. tetani distribution in other regions. We studied C. tetani in topsoil samples collected from private gardens, public road shoulders, a university campus, mountains, and fields in Sagamihara. C. tetani occurred in 8 of 35 soil samples (22.9%) and tetanus toxin in 7 of the 8 C. tetani-positive samples (87.5%). Contamination was clearly higher in soils from mountains near Tsukui-gun (Kanagawa Prefecture), Minamitsuru-gun, and Uenohara and Koshu cities (Yamanashi Prefecture) than in other regions. These findings suggest that tetanus toxin-producing strains of C. tetani tend to inhabit the topsoil of western Sagaminaha region, as a geographical feature.

Study of nasopharyngeal bacterial flora. Second report. Variations in nasopharyngeal bacterial flora in children aged 6 years or younger when administered antimicrobial agents. Part 1.

In our first report, we investigated nasopharyngeal bacterial flora related to penicillin-resistant Streptococcus pneumoniae (PRSP) and beta-lactamase-negative ampicillin-resistant Haemophilus influenzae (BLNAR) and their relation to acute upper respiratory tract infection (AURTI). This report analyzes the results of a study of nasopharyngeal bacterial flora before the administration of antimicrobial agents in 172 AURTI patients aged 6 years or younger. In addition to Gram staining, microscopic observation, and culturing, a polymerase chain reaction (PCR) method was used to identify PRSP (gPRSP) and BLNAR (gBLNAR) drug-resistant genes. Of the patients analyzed, 90% had acute otitis media (AOM) and were aged 2 years or younger. The antimicrobial agents administered were amoxicillin (34%), clavulanic acid/amoxicillin (11%), cefditren pivoxil (CDTR-PI) (43%), and others (12%). This was particularly true for patients administered CDTR-PI, among whom there were many who had already suffered one or more episodes of AOM by the age of 1 year or younger, and many in which gPRSP were detected (P < 0.01). There was a significant relation between the degree of nasopharyngeal inflammation indicated by leukocyte infiltration images and the amount of S. pneumoniae and H. influenzae detected, which are the main pathogenic bacteria causing AOM (P < 0.01). In addition to leukocyte infiltration images, there were cases in which shedding of ciliated cells was observed and/or giant monocytic cells. Both nasopharyngeal leukocyte infiltration images and/or shed cell findings observed in infant AURTI cases are important indices for the prompt detection of gPRSP and/or gBLNAR and appropriate doses of antimicrobial agents.

Study of nasopharyngeal bacterial flora. Second report. Variations in nasopharyngeal bacterial flora in children aged 6 years or younger when administered antimicrobial agents. Part 2.

This report focuses on changes in the nasopharyngeal bacterial flora before and after administration of antimicrobial agents in 172 cases of acute upper respiratory infection in patients aged 6 years or younger. The antimicrobial agents administered were amoxicillin (AMPC) (34%), clavulanic acid/amoxicillin compound (11%), cefditren pivoxil (CDTR-PI) (43%), and others (12%). Changes in nasopharyngeal bacterial flora were investigated with reexaminations conducted after 2-5 days (day 2-5 subgroup), 6-10 days (day 6-10 subgroup), and 11 days and thereafter. There was a significant reduction in the Streptococcus pneumoniae detected in the group administered AMPC (AMPC group) in the day 2-5 subgroup and the day 6-10 subgroup. There was also a significant decrease in H. influenzae in the group administered CDTR-PI (CDTR-PI group) in the day 2-5 subgroup. From this it was inferred that for the most part significant changes in infectious nasopharyngeal bacteria occurred in the day 2-5 subgroups. However, a significant improvement in the degree of inflammation, as indicated by leukocyte infiltration images for the AMPC group, was observed in the day 2-5 subgroup, and for the CDTR-PI group in the day 6-10 subgroup. On the other hand, in both the antimicrobial agent groups, S. pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis were newly detected at reexamination. Furthermore, a difference in the incidence of these bacteria was observed between the 2 antimicrobial agent groups. It was suggested that such phenomena related to the survival of resistant strains or a recurrence otitis media.

Topoisomerase mutations and efflux are associated with fluoroquinolone resistance in Enterococcus faecalis.

To understand better the mechanisms of fluoroquinolone resistance in Enterococcus faecalis, fluoroquinolone-resistant mutants isolated from Ent. faecalis ATCC 29212 by stepwise selection with sparfloxacin (SPX) and norfloxacin (NOR) were analysed. The results showed the following. (i) In general, fluoroquinolone-resistance mechanisms in Ent. faecalis are similar to those in other Gram-positive bacteria, such as Staphylococcus aureus and Streptococcus pneumoniae, namely, mutants with amino acid changes in both GyrA and ParC exhibited high fluoroquinolone resistance, and single GyrA mutants and a single ParC mutant were more resistant to SPX and NOR, respectively, than the parent strain, indicating that the primary targets of SPX and NOR in Ent. faecalis are DNA gyrase and topoisomerase IV, respectively. (ii) Alterations in GyrB (DeltaKGA, residues 395-397) and ParE (Glu-459 to Lys) were associated with fluoroquinolone resistance in some mutants. Moreover, the facts that the NOR MIC, but not the SPX MIC, decreased in the presence of multidrug efflux pump inhibitors, that NOR accumulation decreased in the cells, and that the EmeA mRNA expression level did not change, strongly suggested that a NorA-like efflux pump, rather than EmeA, was involved in resistance to NOR.

[Inactivation of Cryptosporidium parvum oocysts in copper tubing].

We studied whether the infectivity of Cryptosporidium parvum oocysts for suckling mice could be inactivated by copper tubing or by other types of tubing used to construct water distribution systems, including stainless steel, rigid polyvinyl chloride (PVC), PVC-lined steel, polyethylene (PE), cross-linked PE, and polybutene (PB), using glass tubing as the control. Oocysts were incubated in each tubings for 24 hours. The extent of inactivation of infectious oocysts by copper tubing was -1.303 log, which significantly inactivated of infectivity. In contrast, other types of tubing had no significant effect on some oocyst infectivity, although PB did show a maximum inactivation of -0.313 log. 25% of oocysts showed degeneration morphologically after passing through copper tubing, while 0.3% to 1.8% showed degeneration after passing through other tubing. Significant inactivation of infectious oocysts was not caused by water in which copper tubing had been let stand for 24 hours, although it had a cupric ion (Cu2+) concentration of 2.4 mg/L. The direct contact of oocysts with copper surface resulted in a decrease in the recovery percentage of oocysts and generation of hydrogen peroxide (0.5 mg/L) after 24 h of incubation. The percentage of degenerating oocysts was 29%. Such cryptosporidicidal effects of the copper surface on oocysts were completely inhibited by overlaying the surface with a Millipore filter before adding oocysts and incubating oocysts in the presence of catalase, an antioxidant enzyme. These findings suggest that copper tubing inactivates infectious C. parvum oocysts cytotoxically which may be due to oxygen radicals generated by the interaction between Cu2+ and hydrogen peroxide on the tubing surface.

Combination of known and unknown mechanisms confers high-level resistance to fluoroquinolones in Enterococcus faecium.

In order to elucidate the mechanisms of fluoroquinolone resistance in Enterococcus faecium, spontaneous mutants isolated from Ent. faecium ATCC 19434 by stepwise selection with sparfloxacin (SPX) or norfloxacin (NOR) and 13 clinical isolates of Ent. faecium were characterized by analysing quinolone-resistance-determining regions (QRDRs) of the gyrA, gyrB, parC and parE genes and examining changes in MICs of SPX and NOR in the presence of efflux pump inhibitors. The SPX-selected first-step mutant had a point mutation only in gyrA, and the mutants QR7-18 and QR7-39, and clinical isolates that had point mutations in parC, showed NOR resistance. These results indicate that the primary targets of SPX and NOR are DNA gyrase and topoisomerase IV, respectively, and therefore that the primary target of fluoroquinolones in Ent. faecium differs depending on the structure of the compound used. The characterization of the spontaneous mutants and the clinical isolates demonstrates that in addition to the previously reported alterations in GyrA and ParC, an alteration in GyrB, a NorA-like pump, an unknown efflux pump, which excretes both SPX and NOR from bacterial cells, and probably other unknown mechanism(s) all contribute to fluoroquinolone resistance in Ent. faecium.

Study of upper respiratory tract bacterial flora: first report. Variations in upper respiratory tract bacterial flora in patients with acute upper respiratory tract infection and healthy subjects and variations by subject age.

With the appearance of penicillin-resistant Streptococcus pneumoniae, there has been increasing debate concerning antimicrobial treatments for acute upper respiratory tract infection (AURTI) and acute otitis media in children. This study compares the nasopharyngeal bacterial flora in patients with AURTI (AURTI group; 710 subjects) and healthy subjects (HS group; 380 subjects). The comparisons were made between subjects aged 6 years or younger (0-6 subgroup: 330 subjects), between 7 and 74 years (7-74 subgroup: 668 subjects), and 75 years and older (92 subjects), because the subjects were subgrouped as described above dependent on the maturity of the protective immunity. In the HS group 7-74 subgroup, viridans group streptococci, Staphylococcus aureus, coagulase-negative staphylococci, and Corynebacterium sp. with a detection rate of 10% or more were classified as normal nasal flora (NNF), and Streptococcus pyogenes, Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis were classified as drum cavity pathogens (DCP). In the 0-6 subgroup, although the detection rate for DCP bacteria in the AURTI group tended to be high, it did not reach a significant difference, whereas the detection rate for NNF bacteria was significantly lower. This trend was also observed to some degree in the other age subgroup. In the 0-6 subgroup, leukocyte infiltration observed with a microscope indicated the closest relationship between S. pneumoniae detection rate and detection quantity. These results suggest that in the 0-6 subgroup the tendency for patients with AURTI to have NNF bacteria as well as DCP bacteria should be taken into consideration.

[Nosocomial infection by multidrug-resistant Pseudomonas Aeruginosa (MDRP) presumably spread a radiation technician].

Isolated of multidrug resistance Pseudomonas aeruginosa (MDRP) that the receptivity pattern of the antimicrobial suscepti respectively resembled isolated from clinical specimens (sputum) in two patients of each internal medicine ward in Kitasato University East Hospital for two days from September 18 and 20, 2004. Both of bacteria were formed small colonies of a smooth-type on dollargalluskey improvement-type BTB agar plates, and the judgment of ClassB (metallo)-beta-lactamase by biochemical properties and disk diffusion method sodium mercaoto-acetic acid (SMA) was mutually corresponding. Moreover, it was same serotype C according to the serotype, and it was confirmed that it was the same bacterial strain from the molecular epidemiology analysis by Random amplified polymorphic DNA polymerase chain reaction (Random amplified polymorphic DNA polymerase chain reaction: RAPD). From the investigation of clinical backgrounds of two patients who isolated bacterial strains, September 18, 2004. 10 : 20 a.m., and 10 : 40 a.m., other chances that can become with contact infection in this hospital, except conducted X-Ray or roentgenograph of the chest and abdomen of Portable X-ray device continuously done by one radiation technician was not seen. Because it had turned out that a radiation technician who had taken charge had been neglecting the hand washing at the time of each X-Ray or roentgenograph, it was guessed the case with nosocomial infection by contact infection occurred via specific radiation technician.

Genetic diversity of the C protein beta-antigen gene and its upstream regions within clonally related groups of type Ia and Ib group B streptococci.

C protein beta antigen (Bac), a surface protein of group B streptococci (GBS), is known to concurrently bind the Fc portion of IgA and factor H (FH). The authors' previous work has demonstrated that mRNA expression levels show diversity among clonally related strains containing genes (bac) encoding Bac, with high expression noted in invasive strains. In this study, the bac gene and upstream regions containing putative promoters, three ORFs and an IS1381 insertion sequence were characterized. Three invasive strains showed high bac expression levels and did not show any notable mutations except one strain producing Bac that was able to bind FH but not IgA. A deletion of 51 amino acid residues, including part of the Bac IgA-binding region, was identified and hypothesized to contribute to the loss of the IgA-binding ability of this strain. A vaginal strain that showed somewhat higher bac expression levels and produced Bac lacking immunoreactivity contained an 11 bp deletion, which generated a premature termination codon, in the region preceding the IgA-binding region. In another vaginal strain that did not express bac, disruption of the upstream ORFs of the sensor histidine kinase and DNA-binding response regulator, due to frameshift mutations, was noted although it is not known whether these proteins directly affect bac expression levels. An IS1381 insertion into the promoter region was found in another vaginal strain that showed low expression levels and produced Bac with a significantly larger proline-rich repeat region. These results demonstrate considerable genetic diversity of the bac and upstream regions of invasive and noninvasive GBS, which may contribute to the variability of bac expression levels among those strains.

Antimicrobial susceptibility of respiratory tract pathogens in Japan during PROTEKT years 1-3 (1999-2002).

Data are presented on antimicrobial resistance among isolates of Streptococcus pneumoniae, Streptoco-ccus pyogenes, Haemophilus influenzae, and Moraxella catarrhalis collected in Japan during years 1-3 (1999-2002) of the Prospective Resistant Organism Tracking and Epidemiology for the Ketolide Telithromycin (PROTEKT) surveillance study. In addition to the standard panel of PROTEKT antimicrobial agents, eight other agents often used in Japan also were tested against these isolates. The majority (30%-55%) of S. pneumoniae and H. influenzae isolates were collected from patients with community-acquired pneumonia, whereas most (>70%) S. pyogenes isolates came from patients with tonsillitis/pharyngitis. Penicillin and macrolide resistance were high among isolates of S. pneumoniae, averaging 30.9%-44.5% and 77.2%-79.9%, respectively, across all centers over the 3 study years; the highest occurrences were reported among pediatric patients aged 0-2 years. The erm(B) genotype accounted for >50% of all erythromycin-resistant isolates each study year. S. pyogenes isolates were highly susceptible to most antimicrobial agents except the macrolides and tetracycline. beta-Lactamase production among H. influenzae isolates range was 8.5%-9.7% per annum. A total of 9 beta-lactamase-negative, ampicillin-resistant isolates were collected during the study. Almost all (>95%) M. catarrhalis isolates were beta-lactamase positive each year. Telithromycin was highly active against all pathogens examined in this study during all 3 years.

Novel pathogenetic mechanism in a clinical isolate of Yersinia enterocolitica KU14.

Yersinia enterocolitica induces a broad range of gastrointestinal syndromes, including acute enteritis. We previously reported that the clinical isolate, Y. enterocolitica KU14, which lacks pYV, was still capable of causing clinical infection. The present study demonstrated that KU14 did not trigger the death of macrophages in vitro, unlike WA-314 (ATCC51871, which harbors the pYV virulence plasmid). However, the intracellular growth of KU14 in the macrophages was greater than that of WA-C (ATCC51872, a non-plasmid harboring the derivative pYV plasmid). Treatment with a cholesterol-binding drug (beta-cyclodextrin) that affected lipid rafts resulted in a dramatic reduction in the intracellular growth of KU14. These data clearly indicate that the enhanced intracellular growth of KU14 is related to lipid raft-mediated infection.

Induction of triggering receptor expressed on myeloid cells 1 in murine resident peritoneal macrophages by monosodium urate monohydrate crystals.

OBJECTIVE: Triggering receptor expressed on myeloid cells 1 (TREM-1) is a cell surface molecule that was recently identified on monocytes and neutrophils. TREM-1 has been implicated in the early inflammatory responses induced by microbes, but its pathophysiologic role in nonmicrobial inflammation remains unknown. In the present study, we investigated the role of TREM-1 in acute inflammation induced by monosodium urate monohydrate (MSU) crystals. Induction of TREM-1 expression by MSU crystal-stimulated murine resident peritoneal macrophages and infiltrating leukocytes in a murine air-pouch model of crystal-induced acute inflammation was determined. The biologic role of TREM-1 in crystal-induced cytokine production by resident peritoneal macrophages was also investigated. METHODS: TREM-1 expression by resident peritoneal macrophages and infiltrating leukocytes in a murine air-pouch model was determined by quantitative real-time polymerase chain reaction, Western blot analysis, and flow cytometry. Cytokine production by resident peritoneal macrophages after incubation with MSU crystals in the presence or absence of an anti-TREM-1 agonist antibody was determined by enzyme-linked immunosorbent assay. RESULTS: TREM-1 expression by resident peritoneal macrophages was significantly induced after stimulation with the crystals. Maximum expression of TREM-1 transcripts and protein occurred at 1 and 4 hours after exposure to the crystals, respectively. Costimulation of resident peritoneal macrophages with MSU crystals and an anti-TREM-1 agonist antibody synergistically increased the production of both interleukin-1beta and monocyte chemotactic protein 1 compared with stimulation with the crystals alone. MSU crystals also induced TREM-1 expression in infiltrating leukocytes in a murine air-pouch model of crystal-induced acute inflammation. CONCLUSION: These findings suggest that rapid induction of TREM-1 expression on resident peritoneal macrophages and neutrophils by MSU crystals may contribute to the development of acute gout through enhancement of inflammatory responses.