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Martins M, Rodrigues A, Pedrosa JM, Carvalho MJ, Cabrita A, Oliveira R. Update on the challenging role of biofilms in peritoneal dialysis. BIOFOULING 2013; 29:1015-1027. [PMID: 23998251 DOI: 10.1080/08927014.2013.824566] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Biofilms are commonly associated with an increased risk of patient infection. In peritoneal dialysis (PD), catheter associated infection, especially peritonitis, remains a clinically relevant problem. Although the presence of a biofilm is recognized in relapsing, repeat, and catheter-related peritonitis, it remains poorly characterized. In this review, an update on the role of biofilms in PD infections is presented. The emerging concept that host cells and tissue associated biofilms, in addition to the biofilms on the catheters themselves, contribute to the recalcitrance of infections is discussed. Furthermore, the evidence of biofilms on PD catheters, their developmental stages, and the possible influence of the PD environment are reviewed. The focus is given to ex vivo and in vitro studies that contribute to the elucidation of the interplay between host, microbial, and dialysis factors. The key issues that are still to be answered and the challenges to clinical practice are discussed.
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Affiliation(s)
- Margarida Martins
- IBB-Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, University of Minho, Braga, Portugal
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Hanlon GW, Denyer SP, Hodges NA, Brant JA, Lansley AB, Al-Rustamani WA. Biofilm formation and changes in bacterial cell surface hydrophobicity during growth in a CAPD model system. J Pharm Pharmacol 2010; 56:847-54. [PMID: 15233862 DOI: 10.1211/0022357023817] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Abstract
Peritonitis is a frequent complication of continuous ambulatory peritoneal dialysis (CAPD), with patients suffering recurrent attacks. The microorganisms most frequently implicated in the infection are the skin microflora, in particular, the coagulase-negative staphylococci such as Staphylococcus epidermidis. These microorganisms gain access to the peritoneal cavity via the in-dwelling silicone rubber catheter in the abdominal wall and often persist as biofilms on the surface of the catheter. The surface characteristics of S. epidermidis were monitored during growth in a CAPD in-vitro model together with their ability to adhere to silicone rubber substrata. Fresh dialysis fluid exerted an injurious effect on the cells leading to a decrease in cell numbers but during the simulated dialysis period the cells adapted to the applied stresses. Over a 96-h period in the model both a clinical isolate and a skin isolate of S. epidermidis adopted a more hydrophobic phenotype. The data presented here show that the bacteria grown in this in-vivo reflective CAPD model continually adapt to their environment and become more tolerant to the stresses imposed. The adapted cells were seen to colonise silicone rubber substrata.
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Affiliation(s)
- G W Hanlon
- School of Pharmacy and Biomolecular Sciences, University of Brighton, Moulsecoomb, Brighton, BN2 4GJ, UK.
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Sauermann R, Schwameis R, Fille M, Ligios MLC, Zeitlinger M. Antimicrobial activity of cefepime and rifampicin in cerebrospinal fluid in vitro. J Antimicrob Chemother 2008; 62:1057-60. [PMID: 18658192 DOI: 10.1093/jac/dkn312] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES Though used for infections of the central nervous system, the pharmacodynamics of antimicrobial agents is commonly evaluated only in commercially available bacterial growth media. In the present study, the effects of cerebrospinal fluid (CSF) on bacterial killing by cefepime and rifampicin were investigated. METHODS CSF was collected from patients who did not receive antibiotics. Time-kill curves were performed over 24 h using drug concentrations of 0.25-, 0.5-, 1-, 2-, 4- and 8-fold the respective MIC for the Staphylococcus aureus test strain. Killing curves were performed in Mueller-Hinton broth (MHB), in CSF incubated in ambient air (CSF(AIR)) and in CSF in air with 5% CO(2) (CSF(CO(2))). CO(2) served to adjust the pH of CSF to physiological values. RESULTS Sustained bacterial killing was achieved by cefepime at lower drug concentrations in CSF(CO(2)) than in MHB. In contrast, rifampicin concentrations above the MIC were required to exert sustained killing in CSF(CO(2)). Both drugs were least effective in CSF(AIR). CONCLUSIONS Standard susceptibility tests may lead to over- or underestimation of the activity of distinct antibiotics in CSF. Evaluation of the antimicrobial activity in pH-adjusted CSF can provide useful information on drugs considered for the treatment of bacterial infections residing in CSF.
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Affiliation(s)
- Robert Sauermann
- Division of Molecular Pharmacokinetics and Imaging, Department of Clinical Pharmacology, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria.
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Strijack C, Harding GKM, Ariano RE, Zelenitsky SA. Peritoneal fluid titer test for peritoneal dialysis-related peritonitis. Antimicrob Agents Chemother 2004; 48:1719-26. [PMID: 15105126 PMCID: PMC400586 DOI: 10.1128/aac.48.5.1719-1726.2004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Standard microbiological tests (i.e., MIC) do not account for the unique factors of peritoneal dialysis (PD)-related peritonitis which can significantly influence treatment response. Our goals were to develop a peritoneal fluid titer (PFT) test and to conduct a pilot study of its association with clinical outcome. The methodology was developed by using spent dialysate collected from patients with bacterial PD-related peritonitis prior to the initiation of antibiotics. Dialysate was processed and spiked with antibiotic to simulate two standard intraperitoneal regimens: cefazolin plus tobramycin and cefazolin alone. Thirty-six clinical isolates, including Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, and Pseudomonas aeruginosa, were tested. In the pilot study, dialysate was collected from 14 patients with bacterial PD-related peritonitis. Titers were determined by using each patient's dialysate and infecting pathogen. Titers were highly reproducible, with discrepancies in only 1% of cases. Overall, PFTs were notably higher against gram-positive bacteria (P < 0.0001). The addition of tobramycin increased titers significantly from zero to values of 1/16 to 1/64 against E. cloacae and P. aeruginosa (P < 0.0001). In the pilot study, peritoneal fluid inhibitory titers were significantly associated with clinical outcome, with a median value of 1/96 for patients who were cured compared to 1/32 for those who failed treatment (P = 0.036). In conclusion, this study provides preliminary support for the PFT as a pharmacodynamic index specific to the treatment of PD-related peritonitis. With further characterization and validation in patients, the PFT test may advance the study of antibiotic therapies for PD-related peritonitis.
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Deighton MA, Capstick J, Domalewski E, van Nguyen T. Methods for studying biofilms produced by Staphylococcus epidermidis. Methods Enzymol 2001; 336:177-95. [PMID: 11403072 DOI: 10.1016/s0076-6879(01)36589-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Affiliation(s)
- M A Deighton
- Department of Biotechnology and Environmental Biology, Royal Melbourne Institute of Technology, Bundoora 3083, Victoria, Australia
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Jones DS, McGovern JG, Adair CG, Woolfson AD, Gorman SP. Conditioning film and environmental effects on the adherence of Candida spp. to silicone and poly(vinylchloride) biomaterials. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2001; 12:399-405. [PMID: 15348278 DOI: 10.1023/a:1011240818338] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The reported incidence of colonization of oropharyngeal medical devices with Candida spp. has increased in recent years, although few studies that have systematically examined the adherence of yeast cells to such biomaterials, the primary step in the process of colonization. This study, therefore, examined the effects of oropharyngeal atmospheric conditions (5% v/v carbon dioxide) and the presence of a salivary conditioning film on both the surface properties and adherence of Candida albicans, Candida krusei and Candida tropicalis to PVC and silicone. Furthermore, the effects of the salivary conditioning film on the surface properties of these biomaterials are reported. Growth of the three Candida spp. in an atmosphere containing 5% v/v CO2 significantly increased their cell surface hydrophobicity and reduced the zeta potential of C. albicans and C. krusei yet increased the zeta potential of C. tropicalis (p<0.05). Furthermore, growth in 5% v/v CO2 decreased the adherence of C. tropicalis and C. albicans to both PVC and silicone, however, increased adherence of C. krusei (p<0.05). Pre-treatment of the microorganisms with pooled human saliva significantly decreased their cell surface hydrophobicity and increased their adherence to either biomaterial in comparison to yeast cells that had been pre-treated with PBS (p<0.05). Saliva treatment of the microorganisms had no consistent effect on microbial zeta potential. Interestingly, adherence of the three, saliva-treated Candida spp. to saliva-treated silicone and PVC was significantly lower than whenever the microorganisms and biomaterials had been treated with PBS (p<0.05). Treatment of silicone and PVC with saliva significantly altered the surface properties, notably reducing both the advancing and receding contact angles and, additionally, the microrugosity. These effects may contribute to the decreased adherence of saliva-treated microorganisms to these biomaterials. In conclusion, this study has demonstrated the effects of physiological conditions within the oral cavity on the adherence of selected Candida spp. to biomaterials employed as oropharyngeal medical devices. In particular, this study has ominously shown that these materials act as substrates for yeast colonization, highlighting the need for advancements in biomaterial design. Furthermore, it is important that physiological conditions should be employed whenever biocompatibility of oropharyngeal biomaterials is under investigation.
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Affiliation(s)
- D S Jones
- Medical Devices Unit, School of Pharmacy, The Queen's University of Belfast, Medical Biology center, 97, Lisburn Road, Belfast BT9 7BL, Northern Ireland, United Kingdom
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Brant JA, Hanlon GW, Denyer SP. Development of an in-vitro model to study the growth characteristics of Staphylococcus epidermidis in continuous ambulatory peritoneal dialysis. J Pharm Pharmacol 1998; 50:1195-203. [PMID: 9821670 DOI: 10.1111/j.2042-7158.1998.tb03334.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An in-vitro model of peritonitis in continuous ambulatory peritoneal dialysis (CAPD) has been developed which integrates the parameters of environmental gaseous tension, the changing biochemical profile of the dialysate, and the periodic challenge of fresh fluid. Dwell times of 4 h during the day and 10 h at night were used to reflect the in-vivo situation. Biochemical analysis of dialysate within the model showed that the profiles for creatinine, glucose and protein approximated those found in patients. Staphylococcus epidermidis growing in synthetic dialysis effluent or pooled dialysis fluid were seen to adapt rapidly to the environment after an initial lag phase; a tendency to aggregate together increased over the 50-h period of operation. In conclusion, the results presented here suggest that this in-vitro model creates an environment which is reflective of the in-vivo situation and therefore has potential for the study of peritonitis in CAPD.
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Affiliation(s)
- J A Brant
- Department of Pharmacy, University of Brighton, Moulsecoomb, East Sussex, UK
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10
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Modun BJ, Cockayne A, Finch R, Williams P. The Staphylococcus aureus and Staphylococcus epidermidis transferrin-binding proteins are expressed in vivo during infection. MICROBIOLOGY (READING, ENGLAND) 1998; 144 ( Pt 4):1005-1012. [PMID: 9579074 DOI: 10.1099/00221287-144-4-1005] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Staphylococci express a 42 kDa cell-wall-associated protein which functions as a receptor for the mammalian iron-binding glycoprotein transferrin. To determine whether this transferrin-binding protein (TBP) is expressed during infection, Staphylococcus aureus and Staphylococcus epidermidis were grown in vivo in chambers implanted intraperitoneally in rats. SDS-PAGE and Western blotting of cell wall proteins prepared from staphylococci recovered directly from the chambers revealed the presence of both the TBP and bacterial-surface-associated rat transferrin. To obtain evidence for the in vivo expression of the staphylococcal TBPs in humans, sera and human peritoneal dialysate (HPD) from non-infected patients undergoing continuous ambulatory peritoneal dialysis (CAPD) and sera from healthy human volunteers were screened for anti-TBP antibodies. Western immunoblots revealed that three out of ten samples from the latter group, seven out of ten HPD samples and ten of ten CAPD patient serum samples contained antibodies to the TBP of both S. aureus and S. epidermidis. To gain further insights into the appearance of TBP antibodies, HPD samples were collected over time from CAPD patients whose HPD samples taken immediately after catheter insertion lacked anti-TBP antibodies. In two of these patients, each of whom experienced an episode of peritonitis due to S. epidermidis or Staphylococcus hominis, antibodies to the TBP appeared in the HPD collected immediately post-infection. To determine whether such TBP antibodies were capable of blocking interactions between transferrin and its staphylococcal receptor, HPD immunoglobulin fractions were purified using protein A-Sepharose beads. In competition assays, these immunoglobulins blocked the binding of 125I-labelled transferrin both to whole bacteria and to the isolated 42 kDa TBPs of S. aureus and S. epidermidis. These provide evidence to show that staphylococcal TBPs are expressed in vivo during infection.
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MESH Headings
- Animals
- Antibodies, Bacterial/blood
- Antibodies, Bacterial/immunology
- Antibodies, Bacterial/isolation & purification
- Bacterial Outer Membrane Proteins/analysis
- Bacterial Outer Membrane Proteins/immunology
- Bacterial Outer Membrane Proteins/metabolism
- Blotting, Western
- Carrier Proteins/analysis
- Carrier Proteins/immunology
- Carrier Proteins/metabolism
- Electrophoresis, Polyacrylamide Gel
- Humans
- Iron-Binding Proteins
- Peritoneal Dialysis, Continuous Ambulatory
- Rats
- Rats, Wistar
- Receptors, Transferrin/analysis
- Receptors, Transferrin/immunology
- Receptors, Transferrin/metabolism
- Staphylococcus aureus/chemistry
- Staphylococcus aureus/immunology
- Staphylococcus epidermidis/chemistry
- Staphylococcus epidermidis/immunology
- Transferrin-Binding Proteins
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Affiliation(s)
- Belinda J Modun
- 2 Institute of Infections and Immunity University of Nottingham, University Hospital, Nottingham NG7 2UH, UK
- 1 Department of Pharmaceutical Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Alan Cockayne
- 3 Division of Microbiology, Clinical Laboratory Sciences University of Nottingham, University Hospital, Nottingham NG7 2UH, UK
- 2 Institute of Infections and Immunity University of Nottingham, University Hospital, Nottingham NG7 2UH, UK
| | - Roger Finch
- 3 Division of Microbiology, Clinical Laboratory Sciences University of Nottingham, University Hospital, Nottingham NG7 2UH, UK
| | - Paul Williams
- 2 Institute of Infections and Immunity University of Nottingham, University Hospital, Nottingham NG7 2UH, UK
- 1 Department of Pharmaceutical Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK
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Santin M, Wassall MA, Peluso G, Denyer SP. Adsorption of alpha-1-microglobulin from biological fluids onto polymer surfaces. Biomaterials 1997; 18:823-7. [PMID: 9177862 DOI: 10.1016/s0142-9612(97)00004-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A recent study in our laboratory has identified the potential role of urine-derived alpha-1-microglobulin (alpha-1-m) in mediating Pseudomonas aeruginosa adhesion to polystyrene, while other workers have suggested a possible role of the protein in the immunological response. Due to the ubiquitous presence of alpha-1-m in body fluids, the adsorption of the protein from serum, cerebrospinal fluid, urine and used continuous ambulatory peritoneal dialysis fluid onto polystyrene was investigated. The treated surfaces were sequentially immersed in water and increasingly concentrated isopropanol-water solutions in order to selectively desorb bound proteins on the basis of their binding strength. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis of the wash supernatants showed different protein desorption profiles for each biological fluid, despite the qualitative similarity between the protein composition of the fluids, and highlighted the uptake of alpha-1-m from each fluid to the surface. In the case of urine, the analysis was extended to commercial polyurethane and silicone stents. The ease of desorption of urine-derived alpha-1-m could be correlated with surface hydrophobicity of the stent biomaterial.
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Affiliation(s)
- M Santin
- Department of Pharmacy, University of Brighton, UK
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12
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Jones DS, McGovern JG, Woolfson AD, Gorman SP. Role of physiological conditions in the oropharynx on the adherence of respiratory bacterial isolates to endotracheal tube poly(vinyl chloride). Biomaterials 1997; 18:503-10. [PMID: 9111955 DOI: 10.1016/s0142-9612(96)00170-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Pneumonia is a major problem in intensive care patients and can be induced by pathogenic bacteria adhering to poly(vinyl chloride) (PVC) endotracheal (ET) tubes. This study examines the influence of surface properties on the adherence of the respiratory isolates Staphylococcus aureus and Pseudomonas aeruginosa to PVC. In particular, the influence of respiratory tract physiological conditions, 5% CO2 and saliva, on adherence was investigated. In general, decreased adherence to PVC was observed when bacteria were grown in CO2. When these CO2-grown bacteria were treated with saliva their adherence to PVC significantly increased; however, their adherence was significantly reduced to saliva-treated PVC. Treatment of both bacterial isolates with saliva decreased their negative zeta potential, a factor which may directly contribute to the observed increased microbial (saliva pretreated) adherence to PVC. Cell surface hydrophobicity (CSH) was evaluated by measuring the initial rates of microbial removal from a buffered aqueous phase, to ensure the absence of electrostatic interactions, to an organic phase (xylene). Under physiological conditions, CSH did not appear to be a dominant factor in biomaterial adherence as the CSH of S. aureus was decreased by saliva treatment but was unchanged for Ps. aeruginosa. Additionally, CSH also differed for the two isolates when grown in CO2, significantly decreasing with S. aureus but remaining unaltered with Ps. aeruginosa. Saliva treatment of PVC also decreased the advancing and receding contact angles of the biomaterial and its surface roughness, which may be a factor in the decreased adherence of saliva-treated bacteria to this surface. Alternative biomaterials or surface modifications appear necessary for the desired improvements in ET tube effectiveness. This study highlights the influence of physiological conditions on biomaterial and bacterial surface characteristics and subsequent interactions. It is imperative that the physiological conditions predominating in the clinical area of biomaterial use be considered when investigating device biocompatibility.
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Affiliation(s)
- D S Jones
- Pharmaceutical Devices Research Group, School of Pharmacy, Queen's University of Belfast, Northern Ireland, UK
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Cunniffe JG, Whitby-Strevens S, Wilcox MH. Effect of pH changes in cerebrospinal fluid specimens on bacterial survival and antigen test results. J Clin Pathol 1996; 49:249-53. [PMID: 8675739 PMCID: PMC500408 DOI: 10.1136/jcp.49.3.249] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
AIMS To determine the effect of pH changes occurring in cerebrospinal fluid (CSF) after sampling on the viability of meningitis causing bacteria, and on the performance of agglutination assays used for the rapid detection of bacterial antigens. METHODS The pH of CSF collected via lumbar puncture was measured by various methods, and the effects of the following different incubation conditions on subsequent changes were determined: air at 4 degrees C; air at room temperature (22 degrees C); air at 37 degrees C; and air with 5% CO2 at 37 degrees C. The growth/survival in pooled CSF of 15 bacterial isolates collected from 74 patients with meningitis was assessed in these incubation conditions over 24 hours. The effects of pH changes in the CSF on the sensitivity of two latex agglutination and one co-agglutination kits for detecting Haemophilus influenzae, Neisseria meningitidis groups B and C, and Streptococcus pneumoniae were determined. RESULTS The measured pH of CSF was highly affected by the method used and particularly the time delay between patient sampling and assay. Measured pH values at the time of sampling (mean 7.5) increased rapidly within 60 seconds by about one unit. CSF pH continued to increase during incubation in all tested conditions (up to approximately pH 10), with the exception of in air with 5% CO2 at 37 degrees C where pH changes were reversible and near physiological values were attained. Bacterial survival for all species tested was poorest in CSF incubated in air at 37 degrees C and best following exposure to air with 5% CO2 at 37 degrees C. Agglutination in rapid antigen detection kits with CSF incubated in air as opposed to air with 5% CO2 generally took longer to occur and in some instances was less prominent. In one case a false negative result was obtained with CSF seeded with N meningitidis group B incubated in the former but not the latter conditions. CONCLUSIONS CSF pH increases after patient sampling are minimised and/or mostly reversed by incubation in an atmosphere containing 5% CO2. CSF samples should ideally be placed in such an atmosphere as soon as possible after collection, and left there until laboratory processing occurs, to reduce the detrimental effects of pH stress on bacterial survival. pH increases may also reduce the likelihood of obtaining a positive result in rapid antigen detection assays.
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Affiliation(s)
- J G Cunniffe
- Clinical Microbiology and Public Health Laboratory, Addenbrooke's Hospital, Cambridge
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Williams P, Swift S, Modun B. Continuous ambulatory peritoneal dialysis-associated peritonitis as a model device-related infection: phenotypic adaptation, the staphylococcal cell envelope and infection. J Hosp Infect 1995; 30 Suppl:35-43. [PMID: 7560971 DOI: 10.1016/0195-6701(95)90004-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
During the development of infection, pathogens are translocated from one body site to another and so must readily adapt to changing environmental conditions. The influence of host environment on bacterial behaviour and virulence gene expression is, however, often overlooked. Environmental signals such as temperature, pH and nutrient (especially iron) availability which inform pathogens of their living conditions thus contribute to both bacterial survival and virulence. In the context of medical device-associated infections such as peritonitis in continuous ambulatory peritoneal dialysis (CAPD) patients, the pathogenesis of infection is related to the ability of the infecting organism to multiply, to adhere to catheter polymers and host tissues and to evade host defences. Coagulase-negative staphylococci (CNS) such as Staphylococcus epidermidis are commonly responsible for CAPD-associated peritonitis. Although staphylococci cannot grow in commercial peritoneal dialysate solutions, these fluids are modified during dialysis and become enriched by a plasma ultrafiltrate which can support bacteria growth. Given that growth environment exerts considerable influence on bacterial behaviour, the physiology of CNS cultured in vitro in a model system employing pooled human peritoneal dialysate and in vivo in implanted peritoneal chambers in the rat has been investigated. Using such models marked variation in surface physicochemistry, antibiotic susceptibility and adherence to catheter polymers has been observed. This plasticity is clearly reflected in the cell envelope phenotype of CNS, the study of which has recently lead to the discovery of a staphylococcal receptor for the iron-binding serum glycoprotein, transferrin.
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Affiliation(s)
- P Williams
- Department of Pharmaceutical Sciences, University of Nottingham, UK
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Calame W, Hendrickx RJ, Namavar F, Oe LP, Beelen RH. Effect of glucose in dialysis fluid on antibacterial defence in the peritoneal cavity. J Infect 1995; 30:227-33. [PMID: 7673747 DOI: 10.1016/s0163-4453(95)90762-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
To study the effect of glucose concentration and dwell time of dialysis fluid on peritoneal antibacterial defence, an experimental infection with Staphylococcus aureus was induced in rats. For this purpose rats were inoculated intraperitoneally with Staphylococcus aureus at different intervals after the administration of various dialysis fluids. Twenty-four hours later the numbers of bacteria and cells in the peritoneal cavity were determined. The number of bacteria was correlated positively with the glucose concentration. Furthermore, an inverse correlation between dwell time and the number of bacteria was observed. Neither finding could be attributed to a glucose-dependent growth of the bacteria or disruption of the killing capacity of peritoneal cells in vitro. A glucose-dependent increase in the volume of the peritoneal fluid could partially explain the differences found in vivo. It is concluded that the glucose in dialysis fluid impairs antibacterial defence in the peritoneal cavity and that longer dwell times enhance this defence.
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Affiliation(s)
- W Calame
- Department of Cell Biology, Medical Faculty, University Hospital, Vrije Universiteit, Amsterdam, The Netherlands
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Modun B, Kendall D, Williams P. Staphylococci express a receptor for human transferrin: identification of a 42-kilodalton cell wall transferrin-binding protein. Infect Immun 1994; 62:3850-8. [PMID: 8063401 PMCID: PMC303040 DOI: 10.1128/iai.62.9.3850-3858.1994] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Staphylococcus aureus and the coagulase-negative staphylococci are commonly responsible for peritonitis in renal patients undergoing continuous ambulatory peritoneal dialysis. To simulate growth conditions in vivo, staphylococci isolated from peritoneal infections were cultured in used human peritoneal dialysate (HPD). Immunoblotting experiments using cell wall preparations from these staphylococci revealed the presence of the host iron-binding glycoprotein transferrin bound to S. aureus, S. epidermidis, S. capitis, S. haemolyticus, and S. hominis but not to S. warneri or S. saprophyticus. Similar results were obtained by incubating broth-grown staphylococci with human transferrin, although, in contrast to S. aureus, the coagulase-negative staphylococci bound more transferrin after growth in iron-restricted broth. To determine whether the staphylococci express a saturable specific receptor for human transferrin, the interaction of human 125I-transferrin with the staphylococci was examined. Both S. aureus and S. epidermidis bound the radiolabelled iron-saturated ligand in a time- and concentration-dependent manner. From competition binding assays, the affinity (Kd) and number of receptors were estimated for S. epidermidis (Kd, 0.27 microM; 4,200 receptors per cell) and S. aureus (Kd, 0.28 microM; 4,200 receptors per cell). S. epidermidis but not S. aureus receptor activity was partially iron regulated. Human apotransferrin and iron-saturated transferrin and rabbit and rat transferrins competed equally well for the staphylococcal receptor. Bovine and porcine transferrins and ovotransferrin as well as human and bovine lactoferrins were much less effective at competing with human transferrin. Treatment of whole staphylococci with protease abolished transferrin binding, indicating the involvement of cell surface protein. Western blots (immunoblots) of cell wall preparations probed with human transferrin revealed the presence of a 42-kDa transferrin-binding protein common to both S. aureus and S. epidermidis. On Western strip blots, the binding of human transferrin to this protein was blocked by labelled human transferrin but not by albumin, immunoglobulin G, or bovine transferrin or ovotransferrin. To assess the conservation of the 42-kDa transferrin-binding protein, cell wall proteins of S. epidermidis, S. haemolyticus, S. capitis, S. hominis, S. warneri, and S. saprophyticus were Western blotted and probed with human transferrin. Only S. warneri and S. saprophyticus lacked the 42-kDa wall protein, consistent with their inability to bind transferrin. These data show that the staphylococci express a specific receptor for human transferrin based at least in part on a common 42-kDa cell wall protein.
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Affiliation(s)
- B Modun
- Department of Pharmaceutical Sciences, University of Nottingham, United Kingdom
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Wilcox MH, Schumacher-Perdreau F. Lack of evidence for increased adherent growth in broth or human serum of clinically significant coagulase-negative staphylococci. J Hosp Infect 1994; 26:239-50. [PMID: 7915284 DOI: 10.1016/0195-6701(94)90014-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The relevance of adherent growth of coagulase-negative staphylococci (CNS) in vitro to their clinical significance is controversial. We have investigated the accumulation on polymer surfaces of clinically significant CNS strains, isolated from blood cultures and intravascular catheter tips, compared with controls. The adherent growth of significant CNS isolates in a microtitre tray assay was not greater than controls, and this finding was repeated when different combinations of target polymer surface, culture medium and incubation atmosphere type were investigated. The surface accumulation of CNS cultured in pooled human serum was poor compared with culture in broth. Whole cell and surface protein profiles of serum grown Staphylococcus epidermidis differed markedly from broth cultured cells. We recommend the use of human body fluids, such as serum, as useful culture media to assess whether potential virulence determinants are likely to be expressed in vivo. The microtitre tray assay of adherent growth is not helpful in determining the virulence of individual CNS isolates.
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Affiliation(s)
- M H Wilcox
- Department of Experimental and Clinical Microbiology, University of Sheffield Medical School, UK
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Hussain M, Wilcox MH, White PJ. The slime of coagulase-negative staphylococci: biochemistry and relation to adherence. FEMS Microbiol Rev 1993; 10:191-207. [PMID: 8318256 DOI: 10.1111/j.1574-6968.1993.tb05867.x] [Citation(s) in RCA: 107] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
In recent years, infections of implanted plastic devices by coagulase-negative staphylococci have become a major cause of septicaemia in human patients. The causal bacterial species is usually Staphylococcus epidermidis and these organisms grow as a biofilm adherent to a solid surface. Several methods have been introduced to assess the mass of adherent bacteria and the slimy matrix in which they are embedded. Some methods measure total biofilm, others measure the organisms or the slime alone. In vitro, the type of medium, the atmosphere during incubation, and the nature of the solid surface, affect the quantity of biofilm that is formed. In most studies on the chemistry of the slime, the material used was formed on complex media solidified with agar. Contamination by ingredients of the media or by agar may not always have been recognised. Recent work with chemically defined medium (liquid or solidified with silica gel) shows that the slime is a mixture of about 80% (w/w) teichoic acid and 20% protein. Growth as a biofilm may protect the staphylococci from antibiotics. At present, the greatest success in preventing infection has come from improved surgical techniques during the insertion of implants.
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Affiliation(s)
- M Hussain
- Department of Molecular Biology and Biotechnology, The University, Sheffield, UK
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Modun B, Williams P, Pike WJ, Cockayne A, Arbuthnott JP, Finch R, Denyer SP. Cell envelope proteins of Staphylococcus epidermidis grown in vivo in a peritoneal chamber implant. Infect Immun 1992; 60:2551-3. [PMID: 1587623 PMCID: PMC257197 DOI: 10.1128/iai.60.6.2551-2553.1992] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Staphylococcus epidermidis was grown in vivo in chambers implanted intraperitoneally in rats. The cell wall and cytoplasmic membrane protein profiles of the in vivo-grown organisms were compared with those of S. epidermidis grown in vitro in nutrient broth (NB), in iron-restricted NB, or in pooled human peritoneal dialysate (HPD). Compared with growth in broth and in common with growth in HPD, growth in vivo in chambers resulted in the repression of many S. epidermidis wall proteins, with proteins of 27, 42, 54, and 70 kDa predominating. Growth in vivo also resulted in the induction of two iron-repressible cytoplasmic membrane proteins of 32 and 36 kDa, which were also present in staphylococci grown in HPD and in iron-restricted NB. Immunoblotting experiments revealed that in sera taken 21 days after inoculation of the intraperitoneal chambers, the predominant antibody response to cell envelope proteins was directed against the 32- and 36-kDa iron-repressible membrane proteins.
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Affiliation(s)
- B Modun
- Department of Pharmaceutical Sciences, University of Nottingham, United Kingdom
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Hussain M, Wilcox MH, White PJ, Faulkner MK, Spencer RC. Importance of medium and atmosphere type to both slime production and adherence by coagulase-negative staphylococci. J Hosp Infect 1992; 20:173-84. [PMID: 1348772 DOI: 10.1016/0195-6701(92)90085-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Marked differences in both the production of slime and adherence by Staphylococcus epidermidis were observed when comparing four culture media. Slime isolated from a strain cultured in a chemically defined medium (HHW) in air was chemically indistinguishable from that formed in both HHW and synthetic dialysis fluid (SDF) in air with 5% CO2. The presence of a physiological level of CO2 during culture in tryptone soya broth (TSB) prevented production of slime. It was not possible to separate the constituents of slime from those of the culture medium in bacteria grown in TSB in air using DEAE cellulose. Slime production was notably poor in used peritoneal dialysis fluid (PUD). Adherent growth was marked in HHW and SDF but was poor in TSB and PUD when air with 5% CO2 was used. These findings emphasize the advantages in using chemically defined and biological fluids when studying slime production and adherence by S. epidermidis.
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Affiliation(s)
- M Hussain
- Department of Experimental and Clinical Microbiology, University of Sheffield
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Wilcox MH, Hussain M, Faulkner MK, White PJ, Spencer RC. Slime production and adherence by coagulase-negative staphylococci. J Hosp Infect 1991; 18:327-32. [PMID: 1682375 DOI: 10.1016/0195-6701(91)90194-d] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Characterization of cell envelope proteins of Staphylococcus epidermidis cultured in human peritoneal dialysate. Infect Immun 1991; 59:617-24. [PMID: 1987078 PMCID: PMC257802 DOI: 10.1128/iai.59.2.617-624.1991] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The cell envelope protein profiles of Staphylococcus epidermidis cultured in used human peritoneal dialysate (HPD) differed markedly from those of cells cultured in nutrient broth. Compared with broth-grown cells, many cell wall proteins were repressed in HPD, although three proteins of 42, 48, and 54 kDa predominated and an iron-repressible 130-kDa protein was induced. Growth in HPD also resulted in expression of two cell membrane proteins of 32 and 36 kDa which were iron repressible. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblot analysis using monospecific polyclonal antisera raised against the 32- and 36-kDa proteins revealed considerable antigenic and molecular mass homology among 12 S. epidermidis isolates from patients with continuous ambulatory peritoneal dialysis-related peritonitis. The 32-kDa antiserum also cross-reacted with a 32-kDa S. aureus cell membrane protein. Immunoblots of S. epidermidis cell walls and membranes were also probed with normal human serum and serum and HPD from continuous ambulatory peritoneal dialysis patients. While the cell wall proteins of S. epidermidis appeared to be relatively poorly immunogenic, the 32- and 36-kDa membrane proteins reacted strongly with antibodies present in each of the body fluids evaluated. These results suggest that the highly conserved 32- and 36-kDa iron-repressible proteins are expressed during growth in vivo and may be involved in iron transport, since all 12 S. epidermidis strains examined also produced iron chelators.
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