[Joint prosthesis infection with Staphyococcus lugdunensis: 7 cases]. / Infections à Staphylocoque lugdunensis sur prothèses articulaires: à propos de 7 cas.

Staphylococcus lugdunensis was described in Lyon in 1988. This coagulase-negative staphylococcus is the cause of diverse infections which are often severe, particularly in the field cardiology where numerous publications are available for reference. The severity of S. lugdunensis infection is related to specific virulence factors associated with significant adherence properties despite good sensitivity to antibiotics. Publications dealing with joint prosthesis infections are sparse and the reports available have noted failure of treatment unless the prosthesis is removed. S. lugdunensis can easily be identified with an Api Id 32 Staph battery from BioMerieux. We analyzed seven cases of joint prosthesis infections with S. lugdunensis observed between 1991 and 2005. Four chronic infections were managed using the classical schema of implant removal then reimplantation, using a two-stage procedure for three and a single stage for one. Combined with adequate antibiotic treatment, this method was successful in all four cases. We did however have three cases of failure (two were secondary to a probable hematogenic infection and the other an early postoperative infection); these cases were operated on by early lavage and antibiotic therapy without success.

Behaviour of serum immunoreactive trypsin after serum activation by enterokinase in normal and cystic fibrosis patients. Evidence of a trypsin-alpha 1-proteinase inhibitor complex in some cystic fibrosis patients.

Serum immunoreactive trypsin (IRT) concentrations are elevated in newborn children with cystic fibrosis (CF) and subsequently fall, in most cases, to values below normal. To evaluate the molecular form(s) of IRT present in serum, we have performed serum activation by enterokinase and have measured serum IRT before and after activation. This approach is based on the postulate that enterokinase converts trypsinogen into trypsin, and this trypsin would then be mainly trapped by alpha 2-macroglobulin, thus escaping the assay. This assumption was confirmed in the 28 controls studied, where the mean percentage (+/- S.D.) of IRT recovery after serum activation was 13.7 +/- 2.9. Previous inhibition of alpha 2-macroglobulin by methylamine raised the recovery over 85%, confirming that most of the serum IRT present in controls was in the form of trypsinogen. Identical results were obtained in the serum of 10 obligate heterozygotes and in 57 out of 80 CF patients. In 23 CF patients the mean percentage of IRT recovery after serum activation was 41.6 +/- 17.6. Gel-filtration studies were performed on the sera of the CF patients showing an abnormal increase in the IRT recovery after serum activation. We could demonstrate that IRT was distributed in two fractions: one eluted with the Mr 25,000 protein as usually found in controls and other CF sera, and the other eluted with the Mr 75,000 protein corresponding to a complex of trypsin with alpha 1-proteinase inhibitor. These results show that, in these sera, active trypsin has been directly released in blood. These findings suggest that in some patients with CF, subclinical attacks of acute pancreatitis may occur.

Human pancreatic chymotrypsinogen A: a non-competitive enzyme immunoassay, and molecular forms in serum and amniotic fluid.

A sandwich enzyme immunoassay has been developed for human pancreatic chymotrypsin(ogen) using polystyrene balls coated with specific IgG as the first antibody and peroxidase-labelled IgG as the second antibody. The detection limit was 0.5 microgram/l. A good parallelism was observed with the curves obtained from standard chymotrypsinogen A and chymotrypsin(ogen) present in pancreatic juice; however, a slight discrepancy in parallelism with chymotrypsin(ogen) present in serum and amniotic fluid was noticed. Chymotrypsinogen concentration in pancreatic juice was evaluated to represent 9% of total proteins. Mean values of chymotrypsin(ogen) in human sera were 24.6 +/- 8.3 micrograms/l in adults and 20.9 +/- 8.8 micrograms/l in newborns. In amniotic fluid at the 18th week of pregnancy the values were scattered (5-70 micrograms/l). The molecular forms of immunoreactive chymotrypsin(ogen) in normal serum and amniotic fluid have been investigated by gel filtration on Sephadex G-100. Two peaks of immunoreactive chymotrypsin(ogen) were observed in normal serum; the first peak elutes in a position consistent with a complex of chymotrypsin with serum inhibitor (Mr 76,000), and the second peak elutes with a molecular weight of approx. 25,000 corresponding to the elution position of free chymotrypsin(ogen). In normal amniotic fluid three peaks of immunoreactive material were present; the first and second peaks elute in the same position as in serum, and the third peak with a molecular weight of about 14,500 may represent a degraded form of chymotrypsin.

Identification of 'cystic fibrosis protein' as a complex of two calcium-binding proteins present in human cells of myeloid origin.

Cystic fibrosis protein is a serum protein characterized by a pI close to 8.4 and present with a higher concentration in serum and plasma of cystic fibrosis carriers than in controls. This protein was found immunologically indistinguishable from the cystic fibrosis antigen isolated from granulocytes and presenting a sequence analogous to that of MRP-8, a calcium-binding protein expressed in the myeloid cell lineage. Using antibodies directed against MRP-8 and its closely associated calcium-binding protein, MRP-14, we demonstrate here that cystic fibrosis protein purified from serum is a complex of the two proteins MRP-8 and MRP-14.

Effect of DNase on the activity of neutrophil elastase, cathepsin G and proteinase 3 in the presence of DNA.

It has been shown previously that DNA binds and inhibits neutrophil elastase (NE). Here we demonstrate that DNA has a better affinity for neutrophil cathepsin G (cat G) than for NE and is a better inhibitor of cat G than of NE. DNase-generated <0.5 kb DNA fragments inhibit NE and cat G as potently as full length DNA. This rationalises our observation that administration of DNase to cystic fibrosis patients does not enhance the NE and cat G activity of their lung secretions. Neutrophil proteinase 3 is not inhibited by DNA and might thus be the most harmful proteinase in inflammatory lung diseases.

Direct double antibody sandwich immunoassay for Pseudomonas aeruginosa elastase.

A direct sandwich enzyme immunoassay was developed in order to quantify Pseudomonas aeruginosa elastase. As a solid phase the wells of a microtitre plate were coated with specific IgG and horseradish peroxidase labelled IgG was used as the second antibody. The detection limit of the assay was 0.26 ng/ml and a good agreement was found with elastolytic activity determined using elastin-Congo red. This assay was simple, specific, sensitive and reproducible, and permits the determination of low levels of elastase.

Non-competitive enzyme immunoassay of human trypsin 1.

A sandwich enzyme immunoassay was developed for human pancreatic trypsin 1 using polystyrene balls coated with specific IgG as the first antibody and peroxidase-labeled IgG as the second antibody. The entire assay takes 6 h and the detection limit is 0.5 microgram/l. The assay can be performed on sera samples or on discs carrying dried blood spots. Good agreement was found with a radioimmunoassay kit. This simple assay could be widely applied to confirm the elevated immunoreactive serum trypsin described in newborn children with cystic fibrosis.

Serum reg protein level is not related to the beta cell destruction/regeneration process during early phases of diabetogenesis in type I diabetes.

OBJECTIVE: In type I diabetes mellitus, early markers of beta cell damage are needed in order to detect the infraclinical development of the disease. The reg protein may be a good candidate, as the reg gene has been proposed to play a role in the pancreatic beta cell destruction/regeneration process during diabetogenesis in animal models of autoimmune diabetes. The aim of this study was to test the hypothesis whether serum reg protein level could be representative of either the destructive or regenerative process at the beta cell level during the early phases of type I diabetes in humans. DESIGN AND METHODS: We used a highly specific immunoassay to measure serum reg protein level in controls and in three groups of either diabetes prone or diabetic subjects: recently diagnosed diabetic patients, long-standing diabetic patients and islet cell antibody-positive non-diabetic subjects. RESULTS: We found no significant difference between the values observed in these three groups in comparison with control group (90.7+/-18.1ng/ml, 83.1+/-5.6ng/ml, 98.7+/-24.5ng/ml vs 85.5+/- 5.6ng/ml respectively). Moreover, when the insulin reserve was evaluated at 6 months in the recently diagnosed group, serum reg protein levels were not different between patients with or without residual insulin secretion (at onset: 103+/-42 vs 70.3+/-8. 5ng/ml respectively; at 6 months: 79.7+/-25.8ng/ml vs 81.6+/-15ng/ml respectively). In contrast, trypsin levels were significantly lower in every group of diabetic patients. Results were expressed as means +/- S.E.M. and groups compared by Student's t-test (P<0.05). CONCLUSIONS: We conclude that serum reg protein level cannot be used as a marker for the progression of the diabetogenic process in type I diabetes.

Human pancreatic reg protein immunoenzymatic assay and molecular form in serum.

A direct sandwich immunoassay was developed to quantify the human reg protein, a non enzymatic pancreatic acinar protein the biological function of which remains elusive. Polystyrene balls were coated with specific IgG fraction as the first antibody and horseradish peroxidase labelled IgG was used as a second antibody. The linearity of the assay was good over a concentration range of 1.25-100 ng/ml and the good parallelism obtained between the standard and the assay dilution curves in serum and pancreatic juice indicates the absence of non-specific interfering reactions. Gel filtration of serum showed that the reg protein was eluted in the fractions corresponding to the proteins of around 25 kDa and that the chromatographic behaviour of the serum protein was identical to that of the purified pancreatic protein when added to serum. This assay was simple, specific, sensitive and reproducible and may permit the determination of low levels of reg protein in different biological fluids.

Assay of human pancreatic lipase in biological fluids using a non-competitive enzyme immunoassay.

A sandwich enzyme immunoassay has been developed for human pancreatic lipase using polystyrene balls coated with specific IgG as the first antibody and peroxidase-labelled IgG as the second antibody. The detection limit was 0.5 microgram/l. Good parallelism was observed with the curves obtained from standard lipase and lipase present in serum, pancreatic juice and duodenal contents, demonstrating that the assay may be used to measure the level of the protein in different biological fluids. Mean values of lipase in human sera were 12.3 +/- 6.8 micrograms/l in adults and 4.5 +/- 2.7 in newborns. In all cases a good correlation was found in serum between the catalytic activity and the enzyme immunoassay. Lipase is detectable in amniotic fluids at the 18th week of pregnancy but at a very low level (0.95 +/- 0.32 microgram/l). In pancreatic juices, lipase concentration was 14.6% of the total protein content. A study on cystic fibrosis patients showed a poor correlation between blood pancreatic lipase concentration and fat malabsorption underlying the difficulty in assessing pancreatic function by the measurement of serum pancreatic enzymes. The use of the lipase assay in duodenal contents would permit better assessment of pancreatic function in patients presenting a severe or borderline defect in fat digestion and absorption.

Exocrine pancreatic function in cystic fibrosis.

Pancreatic dysfunction in cystic fibrosis (CF) begins in utero and, at birth, in most cases, cystic fibrosis is characterized by an elevated level of serum immunoreactive trypsin (IRT). If most patients with CF typically present insufficient pancreatic exocrine function, 10-15% of CF patients have pancreatic sufficiency and this status is genetically determined by one or two 'mild' mutations in CF transmembrane conductance regulator (CFTR). However, with age, these patients can develop pancreatic insufficiency.

[Ten-year surveillance of nosocomial surgical site infections in an orthopedic surgery department]. / Bilan de 10 ans de surveillance du taux d'infections du site opératoire dans un service d'orthopédie.

PURPOSE OF THE STUDY: Surveillance of nosocomial surgical site infections was instituted in our department in June 1991. We report our first nine years experience. MATERIAL AND METHODS: This study concerned the first 9 years (June 1991-June 2000) of a surveillance program designed to monitor nosocomial surgical site infections in our orthopedic surgery department. During this period 9,696 patients underwent surgery, including 2745 for hip replacements and 1016 for knee replacements. The diagnosis of infection was based on the Centers of Disease Control criteria. Beginning in 1997, the program was widened to include all indications for prophylactic antibiotics, being limited before that time to indications for arthroplasty and spinal surgery. RESULTS: The overall rate of infection was 1.25%; 0.55% for hip arthroplasty and 1.77% for knee arthroplasty. The rate of infection among hip surgery patients over the last 5 years was much higher for prosthesis revision (2.37%) than for first-intention implantations (0.16%). The majority of the isolated strains were Gram-positive (84%) including Staphylococcus sp. found in 65% of the cases. Multiple-strains were found in 23% of the infections. The rate of infection improved very significantly over the last five years both for knee arthroplasty and spinal surgery. The rate remained unchanged for hip arthroplasty. DISCUSSION: This 10-year survey enabled us to analyze the difficulties encountered and pinpoint errors or insufficiencies in data recording. We were also able to identify measures to be taken concerning patient follow-up. The improvement in the rate of infection over time appears to be multifactorial, undoubtedly related to wider use of prophylactic antibiotics, progress in hygiene and sterilization methods with institution of a quality assurance program, and team awareness. CONCLUSION: Surveillance of nosocomial infections is a recommended practice. We have found that the information provided can be beneficial if the data is statistically sound, pointing out the need for progress in patient follow-up.

[Revision of infected total hip prostheses by ablation reimplantation of an uncemented prosthesis. 57 case reports]. / Reprise des prothèses totales de hanche infectées par ablation réimplantation d'une prothèse sans ciment. Expérience de 57 cas.

PURPOSE OF THE STUDY: 57 cases of infected total hip prosthesis treated by removal of the implant and implantation of unncemented prosthesis, were studied to evaluate functional and sepsis results. MATERIAL AND METHODS: 57 patients treated by reimplantation of an uncemented total hip prosthesis after removal of the infected prosthesis were observed. 16 patients underwent a single-stage exchange, 41 a two-stage reimplantation. 46 cases were analysed for infection findings (clinical, radiological and biological assessment) and only 34 cases for functional evaluation (PMA scale, Harris score) with a mean follow-up of 6.6 years. The antibiotic therapy was adapted to each patient but generally, the treatment was prolonged. RESULTS: At follow-up time (which might be too short in time), only 2 patients had a recurrence of infection. One had a single-stage exchange (reoperated by two stage exchange with a good final result at 6 years follow-up), the other a two-stage exchange. In both cases we found that postoperative antibiotic therapy was inadequate. Functional results were better with PMA scale (23 good results of 34) than with Harris score (14 excellent or good results only). 5 patients were reoperated for mechanical implant failure. DISCUSSION: Since 1991, we adopted a standardized procedure to treat chronic infected total hip prosthesis including: routine preoperative aspiration of symptomatic prosthesis; removal of the implant and around debridement followed at a later date (6 weeks) by reimplantation using uncemented implants (hydroxyapatite coated implant). Postoperative antibiotic therapy has to be massive (parenteral bitherapy for at least 21 days after each operative stage) and has to last 6 months after reimplantation. This procedure seems reliable and corroborate the validity of two-stage treatment. The using of uncemented implants allows a good bone reconstruction and does not seem to increase the risk of septic recurrence. CONCLUSION: It is quite difficult to find a hard and fast rule in infected prosthesis treatment, because many factors can influence results. The proposed procedure seems reliable, even if antibiotherapy is long and hard, but requires a strong collaboration between bacteriologist infectiologist and surgeon.