Bacteriophage control of vancomycin-resistant enterococci in cattle compost.

AIMS: To isolate bacteriophage that infects vancomycin-resistant enterococci (VRE) and to investigate the ability of this phage to diminish VRE number in vitro and in experimentally VRE-inoculated compost. METHODS AND RESULTS: We sampled 106 solid or water samples, including 101 bovine faecal samples; lytic phage named Vrep-5 was isolated from one bovine faecal sample by plaque assay using the clinical VRE isolate FN1 (Enterococcus faecium). Vrep-5 generated clear plaques 1 mm in diameter and exhibited characteristics of the family Myoviridae A1, with a spherical head (122 ± 16 nm) and a contractile tail (152 ± 17 nm long). Vrep-5 lysed other bacterial strains, including Enterococcus faecalis. Inoculation of vrep-5 into 0.5 g unsterilized compost experimentally inoculated with FN1 at the multiplicity of infection of 1500 (8.8 × 10(4) CFU g(-1) VRE and 1.3 × 10(8) PFU g(-1) vrep-5) led to a decrease of >3 log(10) in VRE abundance compared with the untreated control after 24 h of incubation. CONCLUSIONS: The data show that bacteriophage vrep-5 is effective in the rapid reduction in VRE colonization in compost. SIGNIFICANCE AND IMPACT OF THE STUDY: The present study gives valuable new knowledge in the fight against VRE in the animal production.

Endoscope disinfection using chlorine dioxide in an automated washer-disinfector.

Although 2% glutaraldehyde is often the first-line agent for endoscopic disinfection, its adverse reactions are common among staff and it is less effective against certain mycobacteria and spore-bearing bacteria. Chlorine dioxide is a possible alternative and an automated washer-disinfector fitted with this agent is currently available. This study was conducted to evaluate the effectiveness of chlorine dioxide in endoscopic disinfection after upper gastrointestinal examination. In vitro microbicidal properties of chlorine dioxide solutions were examined at high (600 ppm) and low (30 ppm) concentrations against various microbes including Pseudomonas aeruginosa, Helicobacter pylori, Mycobacterium avium-intracellulare and Bacillus subtilis in the presence or absence of bovine serum albumin (BSA). Immediately following endoscopic procedures and after application to the automated reprocessor incorporating chlorine dioxide at 30 ppm for 5 min, endoscopic contamination with infectious agents, blood, H. pylori ureA gene DNA and HCV-RNA was assessed by cultivation, sensitive test tape, polymerase chain reaction (PCR) and reverse transcriptase-PCR analysis, respectively. Chlorine dioxide at 30 ppm has equivalent microbicidal activity against most microbes and faster antimicrobial effects on M. avium-intracellulare and B. subtilis compared with 2% glutaraldehyde, but contamination with BSA affected the microbicidal properties of chlorine dioxide. Endoscopic contamination with microbes, blood and bacterial DNA was eliminated after application of the automated reprocessor/chlorine dioxide system. Thus, chlorine dioxide is a potential alternative to glutaraldehyde. The use of automated reprocessors with compatibility to chlorine dioxide, coupled with thorough pre-cleaning, can offer effective, faster and less problematic endoscopic disinfection.

Clinical and molecular epidemiological features of tuberculosis after the 2011 Japan earthquake and tsunami.

OBJECTIVE: To investigate clinical characteristics and prognosis in tuberculosis (TB) patients and the transmission dynamics of TB after the 2011 Japan earthquake and tsunami. METHOD: This was a retrospective observational cohort study. Data were analyzed among 93 pulmonary TB patients (tsunami-affected areas 25, non-tsunami areas 68) hospitalized during March 2011-March 2012 with 1-year follow-up since treatment commencement. Variable number of tandem repeats (VNTR) typing was conducted for 38 TB strains (tsunami-affected areas 21, non-tsunami areas 17). RESULTS: Patients from tsunami-affected areas were significantly more likely to be refugees (OR 12.8, 95%CI 2.45-67.20), receive oxygenation (OR 5.0, 95%CI 1.68-14.85), and have a unique VNTR (OR 4.6, 95%CI 1.14-18.41). Patients who died within 1 year were significantly more likely to be older (OR 9.8, 95%CI 1.85-180.26), partially dependent or dependent (OR 11.9, 95%CI 4.28-37.62), and to require oxygenation (OR 4.3, 95%CI 1.47-12.89), and had lower serum albumin levels (OR 11.1, 95%CI 2.97-72.32). CONCLUSION: Risk factors for prognosis of TB after the earthquake were associated with advanced age, low serum albumin level, functional status at admission, and oxygen requirement. The VNTR results suggest that most of the cases with pulmonary TB experienced reactivation of latent tuberculous infection, likely due to the impact of the earthquake and tsunami.

Deletions of p15 and/or p16 genes as a poor-prognosis factor in adult T-cell leukemia.

PURPOSE: To determine the frequency of the deletions of p15/p16 genes in adult T-cell leukemia (ATL) cells and to evaluate their value in the diagnosis of clinical subtypes of ATL patients and the prediction of their clinical outcome. MATERIALS AND METHODS: Peripheral-blood samples from 114 patients with ATL were examined by Southern blot analysis. In five chronic-type patients who showed disease progression to acute type, serial samples also were examined. RESULTS: Among 114 patients, 28 (24.6%) showed the deletions of p15 and/or p16 genes. The results were well correlated with the clinical subtypes. Patients with deleted p15 and/or p16 genes had significantly shorter survival times than the patients in whom both genes were preserved (P < .0001). A similar decline in survival time was observed in the analyses within the same subtypes. In multivariate analysis using the Cox proportional hazard model, the deletions of p15 and/or p16 genes emerged as an independent prognostic indicator. Moreover, three of the five chronic-type patients who progressed to acute type lost the p16 gene alone or both the p15 and p16 genes at their exacerbation phase. CONCLUSION: The results suggest the following: (1) that the deletions of p15 and/or p16 genes play a key role in the progression of ATL; and (2) that these deletions are reliable prognostic factors that predict shortened survival times.

Chemotherapy targeting methylthioadenosine phosphorylase (MTAP) deficiency in adult T cell leukemia (ATL).

Methylthioadenosine phosphorylase (MTAP) is an important enzyme used for the salvage of adenine and methionine. Cells lacking this enzyme are expected to be sensitive to purine synthesis inhibitors and/or methionine starvation. We reported previously that the MTAP gene is deleted in adult T cell leukemia (ATL) cells. In the present study, we expanded our series and used a real-time quantitative PCR assay for accurate diagnosis of the deletion and nine of 65 primary ATL samples (13.8%) were MTAP negative. In spite of this low incidence, ATL cells showed significantly higher sensitivity to L-alanosine, an inhibitor of de novo adenosine monophosphate (AMP) synthesis, than normal lymphocytes, suggesting that the MTAP gene is inactivated not only by deletion but also by other mechanisms. Indeed, a real-time quantitative RT-PCR assay disclosed that primary ATL cells had significantly lower MTAP mRNA expression than normal lymphocytes. Since MTAP-negative ATL cell lines also showed much higher sensitivity to L-alanosine than MTAP-positive ATL cell lines, we used these cell lines to investigate whether it is possible to develop selective therapy targeting MTAP deficiency. A substrate of MTAP, methylthioadenosine (MTA) or its substitutes rescued concanavalin A (Con A)-activated normal lymphocyte proliferation from L-alanosine toxicity. All the compounds except 5'-deoxyadenosine, however, also caused the undesirable rescue of MTAP-negative ATL cell lines. 5'-Deoxyadenosine had the desired ability to rescue hematopoietic progenitor cells without rescuing ATL cell lines. These results support the rationale for a chemotherapy regimen of L-alanosine combined with 5'-deoxyadenosine rescue in MTAP-deficient ATL.

Qualitative and quantitative characterization of Fas (APO-1/CD95) on leukemic cells derived from patients with B-cell neoplasms.

Expression density and function of Fas (APO-1/CD95) on malignant B-cells, an antigen thought responsible for abnormal tumor biology, remains to be fully understood. Fifty-five cases with B-cell neoplasms of acute lymphoblastic leukemia (ALL), chronic lymphocytic leukemia (CLL), hairy cell leukemia (HCL), B-cell malignant lymphoma (ML), and myeloma (MM) were studied for qualitative and quantitative expression and function of Fas using flow cytometry and annexin-V staining methods. Fas expression was flow cytometrically unimodal with heterogeneous density and showed quantitatively characteristic features among different diseases; weak in ALL, faint in CLL, moderate in HCL, and strong in ML, respectively. Not only full-length but also alternatively spliced truncated mRNAs were detected even in leukemic B-cells with qualitatively faint or negative Fas, and then band density of the former transcripts by RT-PCR was correlated to the Fas protein expression level. Short-term culture of freshly isolated cells gave rise to increases of Fas density and susceptibility for apoptosis, suggesting that the mRNA and inducible Fas are functional at least in vitro. These results show that Fas is a biological marker for characterizing B-cell neoplasms reflecting various stages of B-cell ontogeny and may have clinical utility as a therapeutic strategy.

High-dose rabeprazole-amoxicillin versus rabeprazole-amoxicillin-metronidazole as second-line treatment after failure of the Japanese standard regimen for Helicobacter pylori infection.

BACKGROUND: There is currently no optimal second-line treatment after failure of Helicobacter pylori triple therapy. AIM: To determine effective salvage therapy after failure of lansoprazole-amoxicillin-clarithromycin. METHODS: After failure of lansoprazole-amoxicillin-clarithromycin 123 out-patients were randomized to receive either 2-week rabeprazole (20 mg b.d.) + amoxicillin (1000 mg b.d.) (RA group) or 1-week rabeprazole (10 mg b.d.) + amoxicillin (750 mg twice b.d.) + metronidazole (250 mg b.d.) (RAM group). Eradication was assessed by the 13C-urea breath test. We also evaluated cytochrome p450 (CYP) 2C19 genotype status, determined by polymerase chain reaction - restriction fragment length polymorphism, and susceptibility to clarithromycin and metronidazole. RESULTS: On an intention-to-treat basis, H. pylori infection cure was achieved in 37 of 63 (59%) patients in the RA group and in 49 of 60 (82%) patients in the RAM group. Per protocol-based eradication rates in the RA and RAM groups were 66% (37/56) and 88% (49/56), respectively. In both analytic sets there were significant differences between the treatment groups (P < 0.01 in each). Mild adverse events were observed in eight and five patients from the RA and RAM groups, respectively. Genetic predisposition of CYP2C19 and antibiotic resistance did not influence the treatment outcome either regimen. CONCLUSIONS: The rabeprazole + amoxicillin + metronidazole therapy yielded satisfactory results. In contrast, the cure rate in high-dose rabeprazole + amoxicillin was below an acceptable level.

A protective role for lymphocytes in cyclophosphamide-induced endogenous bacteraemia in mice.

Cyclophosphamide (CY) is used in many animal studies, including models of bacteraemia, to deplete peripheral neutrophils and induce a compromised state. Although CY also influences lymphocyte function, the protective role of lymphocytes in bacteraemia is unclear. Therefore, CY (200 mg/kg) was administered to ddY mice and its influence on the number, cellular composition, and function of lymphocytes in the spleen and Peyer's patches was examined. A single dose of CY reduced the number of lymphocytes in a time-dependent fashion. Flow cytometry showed that B cells carrying B220 antigen decreased significantly. The production of IgA in Peyer's patches, as measured by enzyme-linked immunosorbent assay, was also suppressed in a time-dependent fashion. Blastogenic responses of splenic lymphocytes to Concanavalin-A, lipopolysaccharide and heat-killed Pseudomonas aeruginosa were suppressed 48 h after CY administration. The results suggest that CY suppresses the number and function of lymphocytes, especially B cells. This may lead to bacterial overgrowth in the gut and result in bacteraemia. Intravenous transfusion of normal lymphocytes or oral inoculation of IgA to mice with P. aeruginosa D4 endogenous bacteraemia significantly increased survival rates, indicating that lymphocytes and their products have a protective role in bacteraemia in mice.

The influence of exo-enzyme S and proteases on endogenous Pseudomonas aeruginosa bacteraemia in mice.

The role of Pseudomonas aeruginosa exo-enzymes was evaluated in a murine model of endogenous bacteraemia in which the bacteria invaded the bloodstream after oral dosing. Although an elastase mutant PAO-E64 was as virulent as its parent strain PAO1, an exo-enzyme S-deficient mutant, DG1-ExS5 and alkaline protease mutants PAKS-16, PAKS-17, PAKS-19, were less virulent than their parent strains, DG1 and PAKS-1, respectively (p < 0.01). Thus exo-enzyme S and alkaline protease, but not elastase, appear to contribute to the pathogenicity of P. aeruginosa in this model.

Influence of various immunosuppressive agents on the occurrence of endogenous bacteraemia in mice.

The influence of six immunosuppressive agents on the occurrence of endogenous bacteraemia in mice was evaluated. The mortality rates in conventional ddY mice given cyclophosphamide (CY), fluorouracil (5-FU), methotrexate (MTX), cisplatin (CDDP) or FK-506 intraperitoneally, or dexamethasone (DXM) subcutaneously were 70, 100, 100, 100, 0 and 0%, respectively. Pseudomonas aeruginosa was isolated from 70% of mice treated with CY but from only 10% of mice treated with 5-FU and 30% treated with MTX. Enterobacteria were isolated from 90% of mice treated with 5-FU. Specific-pathogen-free (SPF) mice fed P. aeruginosa were also treated with these agents. All mice in the CY, 5-FU, MTX and CDDP groups died whereas mice treated with DXM and FK-506 showed 20% and 0% mortality, respectively. Pure cultures of P. aeruginosa were obtained from all of the mice treated with CY. Polymicrobial bacteraemia with P. aeruginosa and enterobacteria occurred in 5, 25, 5 and 5% of mice treated with 5-FU, MTX, CDDP and DXM, respectively. Enterobacterial bacteraemia was observed in 70% of mice treated with CDDP and in 5% of the DXM group. Different types of bacteraemia were induced by different immunosuppressive agents. The mechanism of immunosuppression may affect the frequency of bacteraemia and the causative organism.

Experimental endogenous septicaemia caused by Klebsiella pneumoniae and Escherichia coli in mice.

Multi-resistant Klebsiella pneumoniae have recently occurred in several nosocomial outbreaks of septicaemia. An animal model resembling the pathophysiology of these infections in man would be very useful. A new model of endogenous septicaemia caused by K. pneumoniae and Escherichia coli strains in mice has been established. The mortality rate of conventional ddY mice given cyclophosphamide (CY) or fluorouracil (5-FU), each 200 mg/kg intraperitoneally, every other day was 70 and 100%, respectively. Pseudomonas aeruginosa septicaemia was observed in all dead mice treated with CY, whereas Enterobacteriaceae, including K. pneumoniae, were isolated from 90% of mice given 5-FU. Specific-pathogen-free mice, decontaminated with ampicillin and ceftazidime, were given multi-resistant K. pneumoniae CF504, CF514 or E. coli CF604, or CF614 carrying CAZ-1/TEM-5 plasmid by oral inoculation. Subsequent dosing with 5-FU induced lethal septicaemia caused by the inoculated strains in most of these mice, whereas CY did not regularly induce septicaemia. This model with 5-FU is considered to resemble closely the situation observed in man and to be beneficial for investigating pathophysiology and therapeutic strategies.

Effect of clearance of bacteria from the blood on the development of systemic bacteraemia in mice.

Clearance of various bacteria isolated from portal and systemic blood of mice was evaluated and compared. All portal blood strains, including Escherichia coli and enterococci were eliminated more rapidly from the circulation than were strains isolated from systemic blood, including Pseudomonas aeruginosa. With mannose-type lectin, mannose or fucose residues that mediated lectinophagocytosis were detected on the surfaces of most portal strains by agglutination tests. Blood clearance of Esch. coli H21 was inhibited by prior injection of mannose into mice, suggesting that the clearance of this strain was mediated by mannose-type lectin on the surface of tissue macrophages. However, no inhibition of clearance of any other strains was observed by the injection of mannose, galactose, or fucose into mice, nor by pre-incubation of bacteria with mannose. Blood clearance of some portal strains was significantly faster in CBA/J mice than in CBA/N mice with B cell immune deficiency, indicating that immunoglobulin was involved in their clearance. Among portal strains only enterococci showed high cell-surface hydrophobicity. These data suggest that initial bacteria blood clearance may be critical in determining whether latent portal bacteraemia progresses to systemic bacteraemia and that the rapid clearance of most strains is multifactorial.

Mortality rates amongst mice with endogenous septicaemia caused by Pseudomonas aeruginosa isolates from various clinical sources.

Mice that had been treated with cyclophosphamide and ampicillin were fed with Pseudomonas aeruginosa. These procedures induced an endogenous septicaemia under conditions mimicking the pathophysiology of the disease in man. This model was used to compare the mortality rates in mice infected with P. aeruginosa isolates from various clinical sources. Mortality rates in mice given isolates from blood cultures had a broad range (0-100%), but the mean rate was significantly higher than with isolates from other infection sites. Moreover, blood isolates persisted in the intestines of mice after oral inoculation, whereas most isolates from other sources were gradually eliminated. Most P. aeruginosa isolates from blood culture produced significantly higher levels of exotoxin A and total proteases than isolates from other infection sites. Amongst the blood isolates, all but one of the lethal strains produced large quantities of exotoxin A or total proteases or both. Taken together, the results suggest that the ability of P. aeruginosa to adhere to the intestinal tract and to produce high levels of exo-enzymes may contribute to the development of fatal septicaemia.

Effect of immunisation with Pseudomonas aeruginosa on gut-derived sepsis in mice.

The protective efficacy of immunisation with heat-killed Pseudomonas aeruginosa on murine gut-derived sepsis was evaluated. Mice were immunised intraperitoneally six times with heat-killed bacteria. This induced mean (SEM) serum IgG and IgM antibodies of 1792 (374.7) and 37.3 (8.9) ELISA units, respectively. Specific pathogen-free mice given P. aeruginosa strain D4 orally died of bacteraemia after administration of cyclophosphamide. Immunisation with heat-killed bacteria significantly increased the survival rate compared with that of control mice immunised with bovine serum albumin. Macroscopic observation revealed marked production of liver abscesses in mice immunised with bovine serum albumin but not in those immunised with heat-killed bacteria. Only low titres of antibody against the exoenzymes alkaline protease, elastase and exotoxin A were observed, and no significant difference between antibody titres to boiled and unboiled suspensions of sonicated P. aeruginosa was detected. This suggests that the main protective antibodies might be those specific to the heat stable antigen (lipopolysaccharide). Immunisation with heat-killed bacteria provided complete protection against death from gut-derived P. aeruginosa sepsis.

Efficacies of alkaline protease, elastase and exotoxin A toxoid vaccines against gut-derived Pseudomonas aeruginosa sepsis in mice.

The protective efficacies of vaccines prepared from Pseudomonas aeruginosa alkaline protease, elastase and exotoxin A toxoids against gut-derived P. aeruginosa sepsis in mice were evaluated. Specific pathogen-free mice given P. aeruginosa strain D4 orally followed by cyclophosphamide (to promote translocation across the gut wall) died of bacteraemia. Mice immunised with one of the three individual toxoid vaccines were not significantly protected when compared to control mice immunised with bovine serum albumin. Combined immunisation with alkaline protease and elastase toxoids likewise showed no significant protective activity. However, combined immunisation with alkaline protease and exotoxin A toxoids significantly increased the survival rate, which reached 60% (compared with a 7.1% survival rate in the control group). These results show that alkaline protease and exotoxin A play important roles as pathogenic factors in gut-derived sepsis and that a combination of the two exoenzyme toxoids represents a logical candidate for vaccination against P. aeruginosa sepsis.

Detection of Legionella DNA by PCR of whole-blood samples in a mouse model.

A detection system for Legionella DNA in blood samples based on the PCR was developed and evaluated in A/J mice with experimentally induced Legionella pneumonia. Primers were designed to amplify a 106 bp DNA fragment of the 16S rRNA gene specific to Legionella species. The PCR system could detect clinically relevant Legionella species including Legionella pneumophila, Legionella micdadei, Legionella bozemanae, Legionella dumoffii, Legionella longbeachae, Legionella gormanii and Legionella jordanis. The sensitivity of the PCR system was 20 fg extracted DNA. In the mouse model, the blood PCR was compared with results obtained by PCR on bronchoalveolar lavage fluid (BALF) samples, cultures of blood and BALF and detection of Legionella urinary antigen. Blood PCR was positive until 8 days after infection, while BALF PCR became negative on day 4. These results indicate that PCR using blood samples may be a useful, convenient and non-invasive method for the diagnosis of Legionella pneumonia.

Assessment of clinical significance of positive blood cultures of relatively low-virulence isolates.

In Omori Hospital, Toho University School of Medicine, relatively low-virulence blood isolates, including coagulase-negative staphylococci (CNS), enterococci and nonfermentative gram-negative rods other than Pseudomonas aeruginosa comprised c. 60% of total blood isolates. A retrospective study was conducted to assess their clinical significance by reviewing a total of 91 hospital charts. The physicians' assessments of these positive blood cultures as recorded in the charts were classified into four categories--sepsis, possible sepsis, contamination and no comment. The episodes classified as sepsis accounted for 5.0-19.6%. These episodes were also evaluated by a graded clinical significance score based on multiple factors, including number of positive cultures and clinical signs. The scores for the 91 episodes covered a wide range from 1 to 9, indicating that both contaminants and causative organisms may have been involved. The episodes judged as sepsis or possible sepsis tended to have higher scores. The scores for the episodes associated with enterococci were also higher than those involving CNS or non-fermentative gram-negative rods. The scores for episodes associated with intravenous hyperalimentation catheters were higher than those not associated with the catheters.

CD5-expressing B-cell lymphomas/leukemias: relatively high frequency of CD5+ B-cell lymphomas with an overall poor prognosis in Nagasaki Japan.

To characterize CD5+ B-cell neoplasms in Japan, where chronic lymphocytic leukemia (CLL) is rare and of different subtypes in comparison with Western countries, we collected 58 cases of CD5+ B-cell lymphomas/leukemias and analyzed their clinicopathologic features. According to the French-American-British (FAB) and standard histologic classification, the cases corresponded to small lymphocytic lymphoma (SLL, group I; n = 22, consisting of CLL, n = 10, CLL/PL, n = 3, and CLLmixed, n = 7); intermediate differentiated lymphoma/mantle cell lymphoma (IDL/MCL, group II, n = 18); and others with CD5-positive lymphomas (group III, n = 18). The CD5+ B-cell lymphomas showed morphologic and prognostic variability among the three groups. The clinical and immunophenotypic features were remarkably consistent in leukemic disease being seen in 73% of all cases, splenomegaly in 63%, and intense CD19, CD20, surface membrane immunogobulin M (SmIgM) or SmIgM and SmIgD, light-chain expression, and no CD10 expression. The median survival time of groups I, II, and III was 7.8, 3.3, and 0.8 years, respectively. These findings suggest that CD5 antigens may serve as valid markers for the prognosis and clinical features of B-cell lymphomas and that CD5+ B-cell lymphomas with an overall poor prognosis occurs at a relatively high frequency in Japan. This also suggests that a combination of immunophenotypic and morphologic features is of value for characterizing CD5+ B-cell neoplasms.

Clonal analysis of B-cell leukemias and lymphomas using the polymerase chain reaction for the third complementarity determining region of the IgH gene: a study of 75 cases from Nagasaki Japan.

Using semi-nested polymerase chain reaction (PCR), we examined 75 Japanese cases of hematologic malignancies with B-cell antigens including 25 common acute lymphoblastic leukemia (ALL), 13 chronic lymphocytic leukemia (CLL), 28 B-cell malignant lymphoma (B-ML), 2 hairy cell leukemia (HCL), 7 acute myelogenous leukemia with B-cell antigens (AML-B), and 23 controls. When amplified products were analysed by a standard polyacrylamide gel electrophoresis, the sensitivity for detection of clonal IgH rearrangements in each group of ALL, CLL, B-ML, HCL, and AML-B was 88%, 92.3%, 71.4%, 100%, and 57.1%, respectively, with an overall sensitivity of 80.0%. There were no false positive results in any of the control samples. Single strand conformation polymorphism (SSCP) analysis of the amplified products gave rise to a much greater sensitivity, up to 84% overall. The false negative samples were mainly encountered in B-ML with SmIgG and non-Ig, suggesting miss-annealing between the primers used and the template DNA because of somatic hypermutation of IgH genes in such clones. This indicates that PCR analysis is very useful in detecting the clonal IgH rearrangements in B-cell malignancies, especially in ALL and CLL, but not in B-ML corresponding to neoplasms originating from pre-germinal center naive B-cells.

Antimicrobial activity of superoxidized water.

We tested the antimicrobial activity of superoxidized water against methicillin-sensitive Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, Staphylococcus epidermidis, Serratia marcescens, Escherichia coli, Pseudomonas aeruginosa and Burkholderia cepacia. The number of bacteria was reduced below detection limit following incubation in superoxidized water for 10 s. The bactericidal activity of superoxidized water was similar to that of 80% ethanol, but superior to that of 0.1% chlorhexidine and 0.02% povidone iodine. We conclude that superoxidized water is a low cost but powerful disinfectant.