High Levels Of Bacteria Research Articles

Microbial tolerance in secondary peritonitis is dose dependent

Local microbial tolerance was investigated in a murine model of peritonitis. Peritoneal bacterial burden and inflammatory cytokine concentrations were determined at different times, within 48 h after infection. Peritoneal macrophages were harvested from naïve mice or from mice 48 h after infection and underwent ex vivo stimulation with different concentrations of Klebsiella. Cytokine secretion was determined in the supernatants. Peritoneal bacteria concentrations, remained relatively steady between 24 h (median: 5.04 log CFU) and 48 h (median: 5.19 log CFU) after infection. Peritoneal cytokine concentrations peaked early but were already diminished at 48 h after infection, despite persistent high bacteria levels. Macrophages, harvested from naïve mice responded vigorously to ex vivo stimulation with 10 5 CFU and 2 × 10 8 CFU Klebsiella. Cells harvested from animals 48 h after infection, were unresponsive to an ex vivo stimulation with 10 5 CFU Klebsiella, but fully responded to 10 8 CFU. Persistent intraabdominal bacterial infection induced dose dependent microbial tolerance in peritoneal macrophages.

ADDING SILVER AND COPPER TO HYDROGEN PEROXIDE AND PERACETIC ACID IN THE DISINFECTION OF AN ADVANCED PRIMARY TREATMENT EFFLUENT

This paper evaluates the efficacy of hydrogen peroxide (HP) and peracetic acid (PAA) in the disinfection of an Advanced Primary Treatment (APT) effluent, and how said disinfection capacities can be enhanced by combining the oxidants with copper (Cu2+) and silver (Ag). The treatment sequence consisted of APT (adding chemicals to water to remove suspended solids by coagulation and flocculation), followed by disinfection with various doses of HP, HP+Cu2+, HP+Ag, PAA and PAA+Ag. Microbiological quality was determined by monitoring concentrations of fecal coliforms (FC), pathogenic bacteria (PB) and helminth eggs (HE) throughout the sequence. The results revealed that APT effluent still contains very high levels of bacteria as the treatment only removes 1–2 log of FC and PB, but the reduction in the number of viable helminth eggs was 83%. Subsequent disinfection stages demonstrated that both HP+Cu2+ and HP+Ag have a marked disinfection capacity for bacteria (3.9 and 3.4 log‐inactivation, respectively). Peracetic acid on its own was already extremely efficient at disinfecting for bacteria, and the effect was enhanced when combining PAA with silver (PAA+Ag). The best result for HE removal was achieved by combining PAA with silver (PAA+Ag) at doses of 20 + 2.0 mg l−1, respectively. The study concluded that the PAA+Ag and HP+Ag combinations were good alternatives for APT effluent disinfection, because the disinfected effluents met the standards in NOM‐001‐SEMARNAT‐1996, Mexico’s regulation governing the microbiological quality required in treated wastewater destined for unrestricted reuse in agricultural irrigation (≤ 1 helminths per litre). Combining either of these disinfection treatments with a primary method such as APT, therefore, offers an effective and practical way of reducing the health risks normally associated with the reuse of wastewaters.

Construction of a Large Phage-Displayed Human Antibody Domain Library with a Scaffold Based On a Newly Identified Highly Soluble, Stable Heavy Chain Variable Domain

Currently, almost all U.S. Food and Drug Administration-approved therapeutic antibodies and the vast majority of those in clinical trials are full-size antibodies mostly in an immunoglobulin G1 format of about 150 kDa in size. Two fundamental problems for such large molecules are their poor penetration into tissues (e.g., solid tumors) and poor or absent binding to regions on the surface of some molecules [e.g., on the human immunodeficiency virus envelope glycoprotein (Env)] that are accessible by molecules of smaller size. We have identified a phage-displayed heavy chain-only antibody by panning of a large (size, ∼1.5×1010) human naive Fab (antigen-binding fragment) library against an Env and found that the heavy chain variable domain (VH) of this antibody, designated as m0, was independently folded, stable, highly soluble, monomeric, and expressed at high levels in bacteria. m0 was used as a scaffold to construct a large (size, ∼2.5×1010), highly diversified phage-displayed human VH library by grafting naturally occurring complementarity-determining regions (CDRs) 2 and 3 of heavy chains from five human antibody Fab libraries and by randomly mutating four putative solvent-accessible residues in CDR1 to A, D, S, or Y. The sequence diversity of all CDRs was determined from 143 randomly selected clones. Most of these VHs were with different CDR2 origins (six of seven groups of VH germlines) or CDR3 lengths (ranging from 7 to 24 residues) and could be purified directly from the soluble fraction of the Escherichia coli periplasm. The quality of the library was also validated by successful selection of high-affinity VHs against viral and cancer-related antigens; all selected VHs were monomeric, easily expressed, and purified with high solubility and yield. This library could be a valuable source of antibodies targeting size-restricted epitopes and antigens in obstructed locations where efficient penetration could be critical for successful treatment.

Semi-quantitative analysis of Ruminococcus flavefaciens, Fibrobacter succinogenes and Streptococcus bovis in the equine large intestine using real-time polymerase chain reaction

There is a need to further our understanding of the role that the equine hindgut ecosystem plays in digestive processes and diseases. The aim of the present study was to utilise the real-time PCR technique to determine the abundance of candidate cellulolytic (Ruminococcus flavefaciens; Fibrobacter succinogenes) and non-cellulolytic (Streptococcus bovis) bacteria in lumen contents from the caecum, ventral and dorsal colon, and rectum of healthy horses (n 14). Total DNA was extracted from frozen and lyophilised lumen contents, and PCR primers and Taqman probes were designed based on 16S rDNA sequences for specific detection of candidate bacterial species. Overall, in frozen and lyophilised digesta, there were significantly (P F. succinogenes > S. bovis (P < 0.05), while in lyophilised digesta R. flavefaciens was present in significantly (P < 0.05) greater amounts than F. succinogenes and S. bovis. R. flavefaciens and F. succinogenes were abundant at significantly (P < 0.05) greater levels in lyophilised digesta v. frozen digesta, with no difference in S. bovis levels. These data indicate that for these bacteria at least, faeces are a suitable model for studying the bacterial ecosystem within the equine colon. The present study also indicates that the preservation method of digesta affects levels of bacteria detected.

Bacterial Contamination of Hospital Bed-Control Handsets in a Surgical Setting: A Potential Marker of Contamination of the Healthcare Environment

Patients undergoing colorectal surgical resections have a high incidence of surgical site infection (SSI). Many patient-specific risk factors have been recognised in association with SSI in such patients, but environmental contamination is increasingly recognised as a contributor to hospital-acquired infection (HAI). This study set out to describe the bacterial contamination of the patient environment, using hospital bed-control handsets, as they are frequently handled by both staff and patients and represent a marker of environmental contamination. On two unannounced sampling events, 1 week apart, 140 bacteriological assessments were made of 70 hospital bed control handsets within a specialist colorectal surgical unit. Of the handsets examined, 67 (95.7%) demonstrated at least one bacterial species (52.9% grew 1, 30% grew 2 and 12.9% grew 3 or more bacterial species). Of these, 29 (41.4%) bed-control handsets grew bacteria known to cause nosocomial infection, including 22 (31.4%) handsets which grew Enterococcus spp., 9 (12.9%) which grew MRSA, 2 (2.9%) which grew MSSA, 2 (2.9%) which grew coliforms, and 1 (1.4%) handset which grew anaerobes. At 1-week follow-up, 31 bed-control handsets showed evidence of contamination by the same bacterial species. This study revealed high levels of bacteria known to cause HAI, contaminating hospital bed-control handsets in a surgical setting. Further study is now required to confirm whether hospital environmental contamination is causally involved in SSI.

Identification and management of microbial contaminations in a surface drinking water source

Microbial contamination of surface waters constitutes a health risk for drinking water consumers which may be lowered by closing the raw water intake. We have evaluated microbial discharge events reported in the river Göta älv, which is used for raw water supply to the city of Göteborg. Elevated levels of faecal indicator bacteria were observed during periods of closed raw water intake. High bacteria levels were, however, also occasionally detected during periods of open intake, probably as a result of microbial discharge far upstream in the river which may be difficult to predict and manage by closing the intake. Accumulated upstream precipitations, resulting in surface runoff and wastewater contaminations in the catchment, correlated positively with the levels of total coliforms, E. coli, intestinal enterococci and sulfite-reducing clostridia. Levels of faecal indicator organisms were negatively correlated to the water temperature due to enhanced survival at lower temperatures. Wastewater discharges from a municipality located just upstream of the water intake resulted in elevated E. coli concentrations downstream at the raw water intake for Göteborg. To improve the prediction of microbial contaminations within the river Göta älv, monitoring data on turbidity and upstream precipitation are of particular importance.

Guidelines for the treatment of venous ulcers

1. Co-chaired this panel2. University of South Florida, Tampa, FL3. Healthpoint Ltd., Fort Worth, TX4. University of California, San Francisco, CA5. University of Texas Medical Branch, Galveston, TX6. University of Cardiff, Cardiff, Wales, UK7. University of Pennsylvania, Philadelphia, PA8. Private practice, Warren, PA9. Private practice, Tamarac, FL10. University of Pittsburgh, Pittsburgh, PA11. St. Louis University, St. Louis, MO, and12. Washington University, St. Louis, MO

The significance of dilution in evaluating possible impacts of wastewater discharges from large cruise ships

In response to public concerns about discharges from large cruise ships, Alaska’s Department of Environmental Conservation (ADEC) sampled numerous effluents in the summer of 2000. The data showed that basic marine sanitation device (MSD) technology for black water (sewage) was not performing as expected. Untreated gray water had high levels of conventional pollutants and surprisingly high levels of bacteria. Both black water and gray water discharges sometimes exceeded state water quality standards for toxicants. The state convened a Science Advisory Panel (the Panel) to evaluate impacts associated with cruise ship wastewater discharges. The effluent data received wide media coverage and increased public concerns. Consequently, legislative decisions were made at the State and Federal level, and regulations were imposed before the Panel completed its evaluation. The Panel demonstrated that following the rapid dilution from moving cruise ships, the effluent data from the Summer of 2000 would not have exceeded water quality standards, and environmental effects were not expected.

Effects of an activated charcoal silver dressing on chronic wounds with no clinical signs of infection

This exploratory, clinical study aimed to explore the effect of an activated charcoal silver dressing (intervention) with cleansing and debridement (control) in reducing the level of bacteria in chronic wounds with no clinical signs of local infection. Patients were randomly assigned to the intervention or control group and monitored for two weeks. Samples for bacterial status and cultivation were obtained by surface smear (spatula) and percutaneous aspiration first at baseline and then after 15 days of treatment. Sixty-seven lesions were included in the intervention group and 58 in the control group. At baseline, in the intervention group 71.6% of the wounds were contaminated, 7.5% had a high level of bacteria and 20.9% were infected. In the control group at baseline 65.5% of the wounds were contaminated, 6.9% colonised, 6.9% had a high level of bacteria and 20.7% were infected. There were no colonised wounds in the intervention group. After two weeks, combining totals of contaminated, colonised, a high level of bacteria and infection for each group, 85.1% (57/67) of the wounds in the intervention group had a positive bacterial level management (that is, a reduction in the number of bacteria in the wound) compared with 62.1% (36/58) in the control group (p=0.003). Activated charcoal dressings that contain silver control infection and reduce healing times, eliminating bacterial barriers.

Some aspects of complex interactions involving soil mesofauna: analysis of the results from a Scottish woodland

Stepwise regression modelling and canonical correspondence analysis were used to analyse data on soil properties and the abundance of soil mesofauna collected from a woodland typical of the Borders of Scotland. The pattern of relationships revealed by stepwise regression models was different for each month, and the models compiled on the overall dataset were generally weaker than those compiled for separate months. Functional relationships among different microarthropods revealed by stepwise regression modelling are summarised in a structural model of their statistical associations. Interpretation of specific relationships revealed is given and implications for dynamic simulation models are discussed. Canonical correspondence analysis revealed that both microbial feeding nematodes (MF) and plant feeding nematodes (PF) appear to prefer a high level of bacteria and moisture, glomalin and organic matter in the soil. Close scrutiny, however, reveals that microbial feeding nematodes have a particularly high affinity to the sites with a high level of bacteria and organic matter, whilst plant feeding nematodes appear to be more associated with moisture and glomalin. Folsomia candida was abundant in sites with a higher pH level (pH ranged between 3.1 and 4.9), but was not abundant in sites with high ergosterol or a high bacteria, moisture, glomalin and organic matter level. However, other Collembola (mainly represented by Folsomia quadrioculata) appeared to be associated with high levels of ectomycorrhizal fungi. As F. candida is known to feed on fungal food sources, the results suggest that the relatively high local abundances of this collembolan might have caused local declines in ectomycorrhizal fungi, reflected, in turn, in the increase in pH. In addition, environmental plasticity of this species might have allowed them to expand into areas with low fungal density by utilising alternative food sources. The fact that F. candida was a dominant microarthropod in the majority of the samples collected in this research also supports this point. However, for those samples where F. candida were less abundant, overcompensatory fungal growth due to grazing by mites and other Collembola was implicated. Overall, our results suggest that both direct negative and indirect positive effects of the microarthropod community on specific fungal groups appear to take place. The differential effect of specific mesofaunal groups on other soil biota justifies their detailed representation in dynamic simulation models of soil ecosystems.

Effects of different water treatment methods and antibiotic addition on larval survival and gut microflora development in Atlantic halibut ( Hippoglossus hippoglossus L.) yolk-sac larvae

The survival of Atlantic halibut ( Hippoglossus hippoglossus) yolk-sac larvae and the development of their gut bacterial flora were compared in pilot-commercial scale rearing trials under different conditions. Four different treatments were tested; water recirculation using non-disinfected embryos (RN); water recirculation using disinfected embryos (RS); flow-to-waste water with disinfected embryos (F); flow-to-waste water with disinfected embryos and addition of antibiotics, oxytetracycline, oxolinic acid and amoxycillin at 20 mg l −1 (FA). Mean survival was greatest in the FA group (53%), which was significantly higher ( p<0.01) than group F (28.8%). Both of the recycled water groups performed relatively well (42.3% survival for group RN and 47.8% for group RS), and physical environmental conditions were most stable in the two recycled water groups. The average incidence of abnormal developmental morphologies was low with an average of >71% morphologically normal larvae in all treatments. Addition of antibiotics appeared to prevent the colonisation of yolk-sac larvae by Marine Agar (MA)-culturable bacteria (<10 CFU/larva for group FA compared to 9.6×10 2 CFU/larva for group F). Higher levels of bacteria were recovered from both groups of larvae reared in recycled water (5.8×10 3 CFU/larva for group RN and 7.79×10 3 for group RS), indicating that bacterial abundance is not, in itself, a determinant of survival. Differences in the types of bacteria that colonised the halibut yolk-sac larvae under the different rearing regimes were described by characterization of the isolates. There appeared to be a relationship between larval survival rate and the presence, or absence, of certain phenotypes. In particular, the gut microflora in the poorest performing group (group F) was dominated by isolates biochemically and morphologically distinct from the predominant Pseudoalteromonas species isolated from the better performing recycled water groups. This lends weight to the hypothesis that certain types of bacteria may act as opportunistic pathogens in yolk-sac incubators while others are benign.

Occupational exposure to metalworking fluid mist and sump fluid contaminants.

This paper summarizes the analytical and occupational hygiene findings from a recent survey of occupational exposure to metalworking fluids (MWFs) in the engineering industry. The aim of the survey was to link MWF mist exposure measurements with particular engineering processes and controls, and utilize the data obtained to develop exposure standards. At the same time the opportunity was taken to assess fluid management and control, including bacterial and fines contamination in the machine sumps. In general, occupational exposure to mineral oil MWF mist was controlled to <3 mg/m(3) (8 h time-weighted average) and to <1 mg/m(3) for water-mix MWF mist (in terms of the concentrate). These exposure values do not necessarily represent best practice, but are believed to be achievable and representative of industry as a whole. Gravimetric analysis of the total inhalable particulate was found to be a good predictor of mineral oil MWF mist but not for water-mix MWF mist. Grinding and drilling operations produced higher exposures than turning and milling for water-mix fluids. There were insufficient data to compare machining operations for mineral oil MWFs. On the whole, fluid management was found to be poor, with most sites failing to meet industry good practice or Health & Safety Executive (HSE) standards. Some of the operating procedures utilized were deficient or unsatisfactory. Poor standards of fluid management were found at all sizes of company. High levels of bacteria, endotoxin and fines were found in sumps, and control of other factors, such as water-mix fluid concentration, was often poor. Mineral oils had higher levels of fines than water-mix fluids (medians of 395 and 18 mg/l, respectively), and grinding produced high levels of fines in both types of MWF. Many water-mix sumps contained bacterial levels of >1 x 10(6) CFU/ml, and endotoxin levels of >100 000 EU/ml were not uncommon. The median values were 109 000 CFU/ml and 8039 EU/ml, respectively. Mists could potentially contain extensive contamination from bacteria and endotoxin. Analysis of the data suggests that sumps operating under typical conditions for machining (a temperature of 20 degrees C, a pH of 9 and a fluid strength below 10%), also appear to provide optimum conditions for the proliferation of bacteria. Low levels of benzo[a]pyrene (median 0.03 micro g/g) were found in the mineral oils, and low levels of N-nitrosodiethanolamine (median 0.4 micro g/ml) were found in the water-mix MWFs. The results of this work will contribute to guidance from the HSE, setting out accepted industry good practice, including guide values for MWF mist and sump fluid contaminants, with significant emphasis on sump fluid management (maintenance and monitoring), as well as control issues.

Monitoring the Purity of Conservation Treatment Waters

In a survey in Sydney, Australia, conservators rated achieving microbiologic and ionic purity of treatment water as high priorities. However, analysis showed high levels of organic/inorganic contaminants in most waters tested and high levels of bacteria in all waters tested. Materials conservation appears to have adopted the water purification technologies of industry but not the monitoring methodologies. An examination of international water quality standards and industrial case studies led to the suggestion that conservation-specific water standards be developed.

Characterization of the CTD Phosphatase Fcp1 from Fission Yeast: PREFERENTIAL DEPHOSPHORYLATION OF SERINE 2 VERSUSSERINE 5

The C-terminal domain (CTD) of RNA polymerase II undergoes extensive phosphorylation and dephosphorylation at positions Ser2 and Ser5 during the transcription cycle. A single CTD phosphatase, Fcp1, has been identified in yeast and metazoans. Here we conducted a biochemical characterization of Fcp1 from the fission yeast Schizosaccharomyces pombe. The 723-amino acid Fcp1 protein was expressed at high levels in bacteria. Recombinant Fcp1 catalyzed the metal-dependent hydrolysis of para-nitrophenyl phosphate with a pH optimum of 5.5 (kcat = 2 s(-1); K(m) = 19 mm). Deletion analysis showed that 139- and 143-amino acid segments could be deleted from the N and C termini of Fcp1, respectively, without affecting phosphatase activity. A segment containing amino acids 487-580, deletion of which abolished activity, embraces a BRCT domain present in all known Fcp1 orthologs. Mutations of residues Asp170 and Asp172 abrogated Fcp1 phosphatase activity; the essential aspartates are located within a 170DXDXT172 motif that defines a superfamily of metal-dependent phosphotransferases. We exploited defined synthetic CTD phosphopeptide substrates to show for the first time that: (i) Fcp1 CTD phosphatase activity is not confined to native polymerase II and (ii) Fcp1 displays an inherent preference for a particular CTD phosphorylation array. Using equivalent concentrations (25 microm) of CTD peptides of identical amino acid sequence and phosphoserine content, which differed only in the positions of phosphoserine within the heptad, we found that Fcp1 was 10-fold more active in dephosphorylating Ser2-PO4 than Ser5-PO4.

Inter-relationships between Bacteriological and Chemical Variations in Lake Pamvotis—Greece

The relationships between indicator bacteria and the organic load were conducted over a year in Lake Pamvotis, in northwest Greece. Total coliforms (TC) and fecal coliforms (FC) were found in water samples from five different sampling stations. Organic load was estimated using biological oxygen demand (BOD) and chemical oxygen demand (COD) parameters. Increased TC and FC levels were found close to heavily polluted areas. Near-bottom samples had higher levels of bacteria and the numbers of TC and FC were increased during rainfall periods. Low or negative correlations were also observed between the bacteriological indices and BOD and COD levels, thus strengthening the hypothesis that indicator bacteria mainly depend upon the origin of pollution rather than the amount of the organic load. It is conceivable that systematic bacteriological and chemical indices must be monitored in order to evaluate the ecosystem and to protect public health.

Microbial overgrowth in water perfusion equipment for esophageal/rectal motility

Background: There are few data on microbial levels in water used during the assessment of GI motility. Patients undergoing such procedures may be ingesting water with unacceptably high levels of bacteria. Methods: Samples of water from the reservoir and tubing from water perfusion motility equipment were taken and quantitatively assessed to determine the concentration of viable aerobic and facultative microorganisms. Interventions were evaluated to determine which reprocessing schedule ensures absence of overgrowth by microbes within the system during storage. Results: Bacterial overgrowth can occur in manometry systems with bacterial levels of greater than 104 colony-forming units (cfu)/mL in the water from both the reservoir and the tubing. Organisms detected included Serratia marcescens, Burkholderia species, and other gram-negative nonfermentors. Eradication of these organisms was difficult, and the only intervention that consistently ensured bacterial water levels below 200 cfu/mL (i.e., within potable water guidelines) was retrofitting of the pump/tubing with new components combined with a monthly hydrogen peroxide decontamination protocol and a daily drying protocol. Conclusions: The entire tubing path of motility equipment must be stored dry to prevent microbial overgrowth. Additionally, implementation of a motility equipment quality assurance program with water testing 3 to 4 times per year is recommended to ensure that overgrowth is not a problem. (Gastrointest Endosc 2002;55:209-13.)

A small outbreak of Legionnaires' disease in a cargo ship under repair.

It was reported that two mechanics working on a cargo ship under repair in the port of Barcelona had died after having fever. An investigation was made into the possibility of any additional cases and the presence of Legionella pneumophila in the ship they were repairing and in their hotel. The contaminated water system was treated with sodium hypochlorite. Both patients died after having been repeatedly diagnosed as having influenza. The two cases occurred among those who had been working with the pump of the ship's water system, while no cases were observed among the other workers (p = 0.02). Various serogroups of L. pneumophila were isolated from the ship's water pump and distribution system. However, organism of serogroup 1, subgroup Pontiac (Knoxville) were identified with identical deoxyribonucleic acid (DNA) patterns in the lung tissue of one patient and in the cooling water circuit valve of the ship's water pump. The first postintervention control water samples showed no further growth of legionella, but serogroups 4 and 8 were identified 8 months later. This legionellosis outbreak, although small, was highly lethal, probably due to the high levels of bacteria to which the patients were exposed and also because of the failure of correct diagnosis. International recommendations on prevention and control of legionellosis, which include ships under repair, are required.

The kitchen dishcloth as a source of and vehicle for foodborne pathogens in a domestic setting

A sample of 100 'in-use' kitchen dishcloths was obtained from randomly chosen domestic premises and tested for the presence of Staphylococcus aureus, Salmonella and Campylobacter . The total microbial loading was also assessed and a questionnaire completed in order to establish usage patterns of the cloths. Staphylococcus aureus was isolated from 4% of the sponge-type cloths; however, none of the samples was positive for Salmonella or Campylobacter . The TVC on sponges versus cloths and the subsequent ability to transfer organisms to a food preparation surface was significantly different ( p = 0.05). Rinsing both types of dishcloth reduced the number of bacteria transferred considerably. The study found there to be no significant difference ( p = 0.05) in the TVC for wet verses dry, those in-use for extended periods of time and dishcloths used for differing activities. These results demonstrate that the kitchen dishcloth may be contaminated with high levels of bacteria and are able to transfer these organisms onto food preparation surfaces. Whilst Campylobacter and Salmonella were not isolated the role of the dishcloth as a potential vehicle for cross-contamination cannot be minimised.

Prophylactic and therapeutic efficacy of antibodies to a capsular polysaccharide shared among vancomycin-sensitive and -resistant enterococci.

Enterococci are important nosocomial pathogens that are increasingly difficult to treat due to intrinsic and acquired resistance to antibiotics, including vancomycin. A recently described capsular polysaccharide (CP) isolated from Enterococcus faecalis 12030 was used to evaluate the potential efficacy of active or passive immunotherapy regimens as adjunctive treatments. Evaluation of protective efficacy was carried out in immunocompetent mice challenged intravenously (i.v.) with live enterococci. In nonimmune mice, i.v. inoculations resulted in high levels of bacteria in kidneys, spleens, and livers 5 days after challenge. Mice immunized with four 10-microg doses of CP antigen/mouse were protected against challenge with the homologous E. faecalis strain. High-titer opsonic immunoglobulin G was also induced by immunizing rabbits with the purified CP, and passive transfer of this antiserum to mice produced significantly lower bacterial counts in organs than did normal rabbit serum or sterile saline. Antibodies to the polysaccharide isolated from E. faecalis 12030 were protective against Enterococcus faecalis OG1RF and against two serologically related, vancomycin-resistant Enterococcus faecium clinical isolates. Antibodies to this CP antigen were also effective as a therapeutic reagent in mice when passive therapy was initiated 48 h after live bacterial challenge. These data indicate that CP antigens from enterococci are potential targets of protective antibodies and that these antibodies may be useful for prophylaxis and treatment of enterococcal infections.

Differential susceptibility to hypoxia aids estuarine invasion

I examined the resistance of 2 competing estuarine mudsnails, Cerithidea californica (native) and Batillaria attramentaria (exotic), to mortality from microbes and associated alteration of the abiotic environment (i.e., hypoxia). B. attramentaria is displacing C. californica from salt marshes of northern California where the 2 species overlap. I first examined the mortality and distribution of the snails during 2 natural experiments in Bolinas salt marsh (Marin Co., California, USA) that exposed the snails to high bacteria levels and low oxygen conditions for prolonged periods (>3 wk). Second, I conducted 2 laboratory experiments designed to quantify the rates and mechanisms of snail mortality related to bacterial activity. In both the field and the lab, B. attramentaria was significantly more resistant to death by low oxygen. Lab experiments demonstrated that indirect effects of bacte- ria, i.e., low oxygen levels (as opposed to direct infection by bacteria), were responsible for the high mortality rate of C. californica. In the field, C. californica seemed able to mitigate effects of hypoxia by migrating away from sources of high stress, but only when the harmful bacterial activity was highly localized. Ultimately this study illustrates that stress from microbial action differentially affects the 2 competing species and thus contributes to the invader's documented displacement of the native in marshes where they co-occur. Given the growing incidence of eutrophication and associated anoxic conditions in near-shore aquatic environments worldwide, differential susceptibility to hypoxia/anoxia may increasingly contribute to the outcomes of biological invasions in these habitats.