Synergistic induction of periodontal tissue regeneration by binary application of human osteogenic protein-1 and human transforming growth factor-ß3 in Class II furcation defects of Papio ursinus.

BACKGROUND AND OBJECTIVE: Binary applications of recombinant human osteogenic protein-1 (hOP-1) and transforming growth factor-ß3 (hTGF-ß3) synergize to induce pronounced bone formation. To induce periodontal tissue regeneration, binary applications of hOP-1 and hTGF-ß(3) were implanted in Class II furcation defects of the Chacma baboon, Papio ursinus. MATERIAL AND METHODS: Defects were created bilaterally in the furcation of the first and second mandibular molars of three adult baboons. Single applications of 25 µg hOP-1 and 75 µg hTGF-ß(3) in Matrigel(®) matrix were compared with 20:1 binary applications, i.e. 25 µg hOP-1 and 1.25 µg hTGF-ß(3). Morcellated fragments of autogenous rectus abdominis striated muscle were added to binary applications. Sixty days after implantation, the animals were killed and the operated tissues harvested en bloc. Undecalcified sections were studied by light microscopy, and regenerated tissue was assessed by measuring volume and height of newly formed alveolar bone and cementum. RESULTS: The hOP-1 and hTGF-ß(3) induced periodontal tissue regeneration and cementogenesis. Qualitative morphological analysis of binary applications showed clear evidence for considerable periodontal tissue regeneration. Quantitatively, the differences in the histomorphometric values did not reach statistical significance for the group size chosen for this primate study. The addition of morcellated muscle fragments did not enhance tissue regeneration. Binary applications showed rapid expansion of the newly formed bone against the root surfaces following fibrovascular tissue induction in the centre of the treated defects. CONCLUSION: Binary applications of hOP-1 and hTGF-ß(3) in Matrigel(®) matrix in Class II furcation defects of P. ursinus induced substantial periodontal tissue regeneration, which was tempered, however, by the anatomy of the furcation defect model, which does not allow for the rapid growth and expansion of the synergistic induction of bone formation, particularly when additionally treated with responding myoblastic stem cells.

Rapid diagnosis of Clostridium difficile infection by multiplex real-time PCR.

The gold standards for the diagnosis of Clostridium difficile infections (CDIs) are the cytotoxicity assay and the toxigenic culture. However, both methods are time-consuming and the results are not available before 24-48 h. We developed and evaluated a multiplex in-house real-time polymerase chain reaction (PCR) assay for the simultaneous detection of toxigenic strains of C. difficile and the presumptive identification of the epidemic NAP1/027/BI strain from stools. Amplifications were performed using specific primers for tcdB and tcdC on an ABI Prism 7300 (Applied Biosystems). The detection of amplicons was done using TaqMan probes. The analytical sensitivity of the multiplex real-time PCR for detecting tcdB was estimated to 10 CFU/g of stools. This assay was assessed from 881 consecutive unformed stools from patients suspected of having CDI. The gold standard was the toxigenic culture for the diagnosis of CDI and PCR ribotyping for the identification of the NAP1/027/BI strain. The prevalence of positive toxigenic culture was 9.31%. Compared to the toxigenic culture, the sensitivity, specificity, and positive and negative predictive values were 86.59%, 97.43%, 78.02%, and 98.57%, respectively, for the real-time PCR and 70.73%, 100%, 100%, and 97.08%, respectively, for the cytotoxicity assay.

Possible importation and subsequent cross-transmission of OXA-48-producing Klebsiella pneumoniae, France, 2010.

We report the possible first patient-to-patient transmission of Klebsiella pneumoniae with decreased susceptibility to imipenem and producing OXA-48, CTX-M15, TEM-1 and OXA-1 in a French hospital.

Radioactive Waste Storage Materials: Their agr-Recoil Aging.

Ion implantation experiments suggest that the accumulation of alpha-recoil damage in radioactive waste storage materials, which behave like solid-state track detectors, plays a drastic role in their long-term degradation. The understanding of alpha-recoil "aging," overlooked in earlier studies, offers new guidelines for improving waste storage conditions.

Cementogenesis and the induction of periodontal tissue regeneration by the osteogenic proteins of the transforming growth factor-beta superfamily.

The antiquity and severity of periodontal diseases are demonstrated by the hard evidence of alveolar bone loss in gnathic remains of the Pliocene/Pleistocene deposits of the Bloubank Valley at Sterkfontein, Swartkrans and Kromdrai in South Africa. Extant Homo has characterized and cloned a superfamily of proteins which include the bone morphogenetic proteins that regulate tooth morphogenesis at different stages of development as temporally and spatially connected events. The induction of cementogenesis, periodontal ligament and alveolar bone regeneration are regulated by the co-ordinated expression of bone morphogenetic proteins. Naturally derived and recombinant human bone morphogenetic proteins induce periodontal tissue regeneration in mammals. Morphological analyses on undecalcified sections cut at 3-6 mum on a series of mandibular molar Class II and III furcation defects induced in the non-human primate Papio ursinus show the induction of cementogenesis. Sharpey's fibers nucleate as a series of composite collagen bundles within the cementoid matrix in close relation to embedded cementocytes. Osteogenic protein-1 and bone morphogenetic protein-2 possess a structure-activity profile, as shown by the morphology of tissue regeneration, preferentially cementogenic and osteogenic, respectively. In Papio ursinus, transforming growth factor-beta(3) also induces cementogenesis, with Sharpey's fibers inserting into newly formed alveolar bone. Capillary sprouting and invasion determine the sequential insertion and alignment of individual collagenic bundles. The addition of responding stem cells prepared by finely mincing fragments of autogenous rectus abdominis muscle significantly enhances the induction of periodontal tissue regeneration when combined with transforming growth factor-beta(3) implanted in Class II and III furcation defects of Papio ursinus.

Induction of cementogenesis and periodontal ligament regeneration by recombinant human transforming growth factor-beta3 in Matrigel with rectus abdominis responding cells.

BACKGROUND AND OBJECTIVE: In primates and in primates only, the transforming growth factor-b proteins induce endochondral bone formation. Transforming growth factor-b3 also induces periodontal tissue regeneration. Two regenerative treatments using human recombinant transforming growth factor-b3 were examined after implantation in mandibular furcation defects of the nonhuman primate, Papio ursinus. MATERIAL AND METHODS: Class III furcation defects were surgically created bilaterally in the mandibular first and second molars of two adult Chacma baboons (P. ursinus). Different doses of recombinant transforming growth factor-beta3 reconstituted with Matrigel matrix were implanted in the rectus abdominis muscle to induce heterotopic ossicles for subsequent transplantation to selected furcation defects. Twenty days after heterotopic implantation, periodontal defects were re-exposed, further debrided and implanted with minced fragments of induced heterotopic ossicles. Contralateral class III furcation defects were implanted directly with recombinant transforming growth factor-beta3 in Matrigel matrix with the addition of minced fragments of autogenous rectus abdominis muscle. Treated quadrants were not subjected to oral hygiene procedures so as to study the effect of the direct application of the recombinant morphogen in Matrigel on periodontal healing. Histomorphometric analyses on undecalcified sections cut from specimen blocks harvested on day 60 measured the area of newly formed alveolar bone and the coronal extension of the newly formed cementum along the exposed root surfaces. RESULTS: Morphometric analyses showed greater alveolar bone regeneration and cementogenesis in furcation defects implanted directly with 75 microg of transforming growth factor-beta3 in Matrigel matrix with the addition of minced muscle tissue. CONCLUSION: Matrigel matrix is an optimal delivery system for the osteogenic proteins of the transforming growth factor-beta superfamily, including the mammalian transforming growth factor-beta3 isoform. The addition of minced fragments of rectus abdominis muscle provides responding stem cells for further tissue induction and morphogenesis by the transforming growth factor-beta3 protein.

Tamoxifen adjuvant treatment duration in early breast cancer: initial results of a randomized study comparing short-term treatment with long-term treatment. Fédération Nationale des Centres de Lutte Contre le Cancer Breast Group.

PURPOSE: In 1986, The Fédération Nationale desCentres de Lutte Contre le Cancer Breast Group initiated a multicenter randomized trial to assess the usefulness of long-term adjuvant tamoxifen treatment. Short-term adjuvant tamoxifen treatment was to be compared with life long adjuvant tamoxifen treatment. PATIENTS AND METHODS: Patients who were disease-free after 2 to 3 years of adjuvant tamoxifen treatment were eligible for the trial. From September 1986 to May 1995, 3,793 patients were randomized from France, Belgium, and Argentina. A total of 1,882 patients stopped tamoxifen (short-term group), and 1,911 patients were to continue tamoxifen for life (long-term group) at the same dose as previously prescribed. The protocol was modified in February 1997, limiting tamoxifen treatment to 10 years after randomization, thus giving a comparison between a 2- to 3-year treatment and a 12- to 13-year treatment. To date, the median duration of tamoxifen treatment is 30 months in the short-term group, and 70 months in the long-term group. RESULTS: Overall, longer tamoxifen treatment induced a 23% reduction in relapse rates, leading to a 7-year disease-free survival rate of 78%, compared with 72% in the shorter-treatment group. In contrast, overall survival did not differ between the two groups, with a 79% overall survival rate in both groups. This improvement in disease-free survival could be observed in node-positive patients (P: =.001); however, it was not found in node-negative patients. Prolonged tamoxifen treatment corresponded to a significant increase in disease-free survival in estrogen receptor-positive patients (P: =.03) as well as in estrogen receptor-negative patients (P: =.05). Furthermore, longer treatment reduced contralateral breast cancers and did not increase the number of endometrial cancers. CONCLUSION: Although no survival advantage was noted, patients did benefit from longer tamoxifen treatment over 3 years and had significantly better disease-free survival compared with patients who stopped hormonal treatment. Long-term follow-up is needed to assess these results. Most patients in the long-term group are still receiving treatment. Comparison of results as time passes will enable conclusions to be made on the value of long-term treatment over 5 years compared with 2 to 3 years.

Prevalence and pathogenicity of Clostridium difficile in hospitalized patients. A French multicenter study.

BACKGROUND: Although Clostridium difficile is the main agent responsible for nosocomial diarrhea in adults, its prevalence in stool cultures sent to hospital microbiology laboratories is not clearly established. OBJECTIVES: To determine the prevalence of C difficile in inpatient stools sent to hospital microbiology laboratories and to assess the relationship between serotypes and toxigenicity of the strains isolated and the clinical data. METHODS: From January 18, 1993, to July 31, 1993, the presence of C difficile was systematically investigated in a case-control study on 3921 stool samples sent for stool culture to 11 French hospital microbiology laboratories. The prevalence of C difficile in this population (cases) was compared with that of a group of 229 random hospital controls matched for age, department, and length of stay (controls). Stool culture from controls was requested by the laboratory although not prescribed by the clinical staff. Serotype and toxigenesis of the strains isolated were compared. RESULTS: The overall prevalence of C difficile in the cases was twice the prevalence in the controls (9.7% vs 4.8%; P < .001) and was approximately 4 times as high in diarrheal stools (ie, soft or liquid) as in normally formed stools from controls (11.5% vs 3.3%; P < .001). The strains isolated from diarrheal stools were more frequently toxigenic than those isolated from normally formed stools. Serogroup D was never toxigenic, and its proportion was statistically greater in the controls than in the cases (45% vs 18%; chi 2 = 5.2; P < .05). Conversely, serogroup C was isolated only from the cases. Clostridium difficile was mainly found in older patients ( > 65 years), suffering from a severe disabling disease, who had been treated with antibiotics and hospitalized for more than 1 week in long-stay wards or in intensive care. CONCLUSIONS: This multicenter period prevalence study clearly supports the hypothesis of a common role of C difficile in infectious diarrhea in hospitalized patients. Disease associated with C difficile should therefore be systematically evaluated in diarrheal stools from inpatients.

Predicting progression of HIV disease: usefulness of acid-dissociated p24 antigen.

To ascertain whether immune complex dissociation (ICD) improves the value of p24 antigen as a prognostic marker for progression of HIV infection, 53 patients were followed over a 3-year period, including at least one visit per year. All had CD4+ counts at entry > 400/mm3; progressors (n = 18) were defined as having CD4+ counts < 200/mm3 and nonprogressors (n = 35) as having CD4+ counts still > 400/mm3 at the end of follow-up. Serum specimens were collected at each annual visit and assayed for p24 antigen with and without ICD treatment. At entry, the percentage of progressors positive for ICD p24 antigen was significantly higher than the percentage of positive nonprogressors (39% versus 3%, p < 0.01). The sensitivity of p24 antigen over all visits in terms of predicting the progression increased from 61% before ICD to 83% after. The specificity of p24 antigen in terms of predicting progression decreased from 97% before ICD to 89% after. The relative risk of progression in individuals positive for p24 antigen was 6.7 before ICD and increased after ICD to 12.7. When evaluating the respective prognostic value of the p24 antigen and of the ICD p24 antigen, only ICD p24 was significant (RR 10.2, 95% CI 2.2-46.9). ICD p24 antigen appears to be a marker of progression that may be detected earlier than p24 antigen without ICD.

Antibiotic-associated diarrhoea and Clostridium difficile in the community.

BACKGROUND: Clostridium difficile is the main cause of nosocomial infectious diarrhoea and the causative agent of antibiotic-associated colitis. The involvement of C. difficile infection in antibiotic-associated diarrhoea in the community is poorly documented. METHODS: We studied prospectively 266 adult out-patients in the Paris (France) area who were prescribed a 5-10-day course of antimicrobial chemotherapy. Stools were screened for C. difficile before and 14 days after the start of treatment by standard culture, toxigenic culture and testing for the cytopathic effect of toxin B. Patients were requested to note daily stool frequency and consistency. Diarrhoea was defined as the passage of at least three loose stools per day. RESULTS: Forty-six (17.5%) of the 262 assessable patients had diarrhoea during the study period. Diarrhoea was mild and self-limited in all patients, and lasted for only 1 day in 65.6% of cases. C. difficile was isolated before and after treatment from one patient, who did not develop diarrhoea. C. difficile was detected only on day 14 in 10 patients (3.8%). The isolate was toxin producing in seven patients. Four of these seven patients had mild self-limited diarrhoea. Toxin-producing C. difficile was isolated significantly more frequently from patients who had diarrhoea than from those who were diarrhoea free (8.7% vs. 1.4%, P = 0.02). CONCLUSION: The acquisition of toxin-producing C. difficile appears to be frequent during antimicrobial chemotherapy in the community [estimated rate of 2700 (1150-5400) cases per 100 000 exposures to antibiotics]. However, C. difficile is not the main agent of mild antibiotic-associated diarrhoea in out-patients.

Endotoxemia and bacteremia in patients with sepsis syndrome in the intensive care unit.

STUDY OBJECTIVES: To study circulatory endotoxin (ET) in patients with sepsis syndrome (SS) in order to answer three questions: (a) How often and at which concentration is ET present in the plasma of patients with SS and is the presence of ET a prognostic marker in this situation? (b) Is detection of ET helpful in predicting Gram-negative bacterial infections with or without bacteremia? (c) What are the kinetics of clearance of ET concentrations in plasma? DESIGN: Prospective study of consecutive patients fulfilling Bone's criteria for SS. SETTING: Medical ICU in a teaching hospital. PATIENTS: The study included 93 patients. The simplified acute physiologic score was 19 +/- 6, 49 percent were in shock, and 54 percent were mechanically ventilated. The mortality at day 28 was 53 percent. MEASUREMENTS: Endotoxin determinations and blood cultures were performed simultaneously at the onset (day 1) of SS. Samples were collected on several days from 48 patients. Endotoxin concentration was determined using an end point chromogenic Limulus assay. For the first ET determination, the mean circulatory level (mean +/- SEM) was calculated among patients with detectable ET, thus excluding patients with a null value for ET. RESULTS: On day 1, ET was detected in 44 patients (47 percent; 60.2 +/- 16.5 pg/ml) and was statistically more frequent in patients with shock, elevated plasma lactate, and organ failure. There was no statistical difference for age, gender, ratio of PaO2 to fraction of inspired oxygen. Among patients with proven Gram-negative bacterial infection (n = 46), ET was detected in 67 percent as compared with 28 percent without Gram-negative bacterial infection (p = 0.0001). On day 1, among 19 patients who had positive blood cultures with Gram-negative bacteria (GNB), 15 had detectable ET (79 percent, 61 +/- 22 pg/ml). In 14 other patients whose blood cultures were positive for GNB but became negative on day 1, 9 had detectable ET (64 percent; 36 +/- 6.5 pg/ml). Endotoxin declined linearly between days 1 and 4. CONCLUSION: In our study, the plasma ET concentration predicts neither Gram-negative infection, with or without bacteremia, nor the outcome. However, when ET is present in the plasma of patients with SS it remains detectable for a long period of time as compared to its rapid disappearance from plasma of animals or healthy human volunteers receiving ET intravenously. This slow clearance of ET suggests either a continuous release or a defect in its clearance.

CdeA of Clostridium difficile, a new multidrug efflux transporter of the MATE family.

The cdeA gene, cloned from Clostridium difficile clinical strain 714 under the control of its natural promoter made Escherichia coli and Clostridium perfringens resistant to ethidium bromide and acriflavin but had no effect on the susceptibility of the hosts to the following antibiotics: norfloxacin, ciprofloxacin, gentamicin, erythromycin, tetracyclin, and chloramphenicol. However, it was responsible for fluoroquinolone resistance in E. coli when it was cloned under the control of the Plac promoter. Quantitative reverse transcriptase (RT)-PCR showed that growth of C. difficile clinical strain 253 in the presence of subinhibitory concentrations of ethidium bromide significantly increased the transcription of cdeA, but this was not observed with ciprofloxacin. The deduced protein was homologous to the protein sequences of known efflux pumps from the third cluster (the so-called DinF branch) of the multidrug and toxic compound extrusion (MATE) family. CdeA caused ethidium bromide energy-dependent efflux in whole cells of E. coli. Efflux activity was stimulated by addition of Na+ ions, suggesting that CdeA, like other pumps of the MATE family, is a Na+-coupled efflux pump. CdeA is the first multidrug efflux transporter identified in C. difficile.

Genomic fingerprinting of Clostridium difficile isolates by using a random amplified polymorphic DNA (RAPD) assay.

This study describes the use of a new and easy method called random amplified polymorphic DNA (RAPD) assay to distinguish strains of C. difficile. We used two single short primers (AP4 and AP5) with arbitrary nucleotide sequences in a polymerase chain reaction to amplify genomic DNA. The profiles observed after electrophoretic separation were able to distinguish 20 reference C. difficile strains previously serotyped by Delmée's method. The fingerprints of 11 epidemiologically unrelated C. difficile strains clearly yielded a DNA polymorphism between all the strains. Latterly, RAPD profiles of 11 C. difficile strains isolated from 2 independent suspected outbreaks showed, in each case, a predominant banding pattern corresponding to an epidemic strain. These results suggest that RAPD assay could be a valuable tool for epidemiological studies.

Development of a new PCR-ribotyping method for Clostridium difficile based on ribosomal RNA gene sequencing.

PCR-ribotying, a typing method based on polymorphism in the 16S-23S intergenic spacer region, has been recently used to investigate outbreaks due to Clostridium difficile. However, this method generates bands of high and close molecular masses which are difficult to separate on agarose gel electrophoresis. To improve reading of banding patterns of PCR-ribotyping applied to C. difficile, a partial sequencing of the rRNA genes (16S and 23S) and intergenic spacer region has been performed, then a new set of primers located closer to the intergenic spacer region has been defined. The new PCR gave reproducible patterns of bands easy to separate on agarose gel electrophoresis. Each of the 10 serogroups and 11 subgroups of serogroup A produced a different pattern. This typing method has evidenced major qualities such as easiness, rapidity and reproducibility. However, its discriminatory power has to be evaluated to validate its importance as a typing tool for C. difficile.

Persistence of t(4;11) in cytologically normal bone marrow treated ex vivo with Asta-Z.

The chromosomal anomaly t(4;11) is closely related to a specific type of acute leukemia: occurrence in young children, hyperleukocytosis with a particular immunologic phenotype, and poor response to therapy. Allogeneic bone marrow (BM) transplantation has been done in a few cases. We report a case in which a complete remission was obtained after intensive therapy. Because no donor was available, an autologous BM transplantation was performed after purge ex vivo of the BM collection by Asta-Z. Relapse occurred at day 45.

A complex t(3;8;17) involving breakpoint 8p11 in a case of M5 acute nonlymphocytic leukemia with erythrophagocytosis.

The t(8;16)(p11;p13) is a recently described new chromosome rearrangement of acute nonlymphocytic leukemia (ANLL). It appears to be specifically associated with acute monoblastic (AML-M5) or unusual myelomonocytic leukemia with prominent erythrophagocytosis in the leukemic cells. A complex t(3;8;17)(q27;p11;q12) is reported in a case of acute monoblastic leukemia with erythrophagocytosis. Sixteen cases of this t(8;16) and two other variant translocations are reviewed. The pathogenetic mechanism of the variant translocations is discussed, suggesting that the der(8) is a consistent recombinant.

A reverse polymerase chain reaction method for detection of human cytomegalovirus late transcripts in cells infected in vitro.

A rapid and simple application of the polymerase chain reaction is described for the detection of human cytomegalovirus (HCMV) mRNAs in cells infected in-vitro. The method was first used to study the transcription of two HCMV genes, and confirm the link between the transcription of one, encoding for the major capsid protein, and viral replication. The oligonucleotides chosen in this region were specific for HCMV genome and sensitivity experiments showed that a single infected cell in 5 x 10(5) can be detected. Detection of this transcript should be suitable for diagnostic purposes, permitting the distinction between latency and active infection.

Epidemiology of Clostridium difficile-associated infections.

Clostridium difficile is responsible for 15-25% of cases of antibiotic-associated diarrhea (AAD) and for virtually all cases of antibiotic-associated pseudomembranous colitis (PMC). This anaerobic bacterium has been identified as the leading cause of nosocomial infectious diarrhea in adults and can be responsible for large outbreaks. Nosocomial C. difficile infection results in an increased length of stay in hospital ranging from 8 to 21 days. Risk factors for C. difficile-associated diarrhea include antimicrobial therapy, older age (>65 years), antineoplastic chemotherapy and length of hospital stay. Other interventions with high risk associations are enemas, nasogastric tubes, gastrointestinal surgery and antiperistaltic drugs. Prospective studies have shown that nosocomial transmission of C. difficile is frequent but often remains asymptomatic. Patients can be contaminated from environmental surfaces, shared instrumentation, hospital personnel hands and infected roommates. Once an outbreak starts, C. difficile may be spread rapidly throughout the hospital environment where spores may persist for months. Measures that are effective in reducing incidence of C. difficile infections and cross-infection include: (i) an accurate and rapid diagnosis, (ii) appropriate treatment, (iii) implementation of enteric precautions for symptomatic patients, (iv) reinforcement of hand-washing, (v) daily environmental disinfection, and (vi) a restrictive antibiotic policy. C. difficile is a common cause of infectious diarrhea and should be therefore systematically investigated in patients with nosocomial diarrhea.

A European survey of diagnostic methods and testing protocols for Clostridium difficile.

OBJECTIVE: To conduct a survey of the methods used in clinical microbiology laboratories in Europe to diagnose infection with Clostridium difficile. METHODS: A questionnaire was devised and sent to a co-ordinating member of the Study Group in each of eight European countries. This co-ordinator was in charge of forwarding the questionnaire to hospital laboratories arbitrarily selected. The number of laboratories in each country was determined on the basis of one laboratory for 10,000 beds of hospitalization. This questionnaire covered different aspects pertaining to Clostridium difficile associated to diarrhea (CDAD) diagnosis such as circumstances of request, criteria used for undertaking C. difficile investigations, methods used for the diagnosis, etc. RESULTS: A total of 212 questionnaires were completed and submitted for analysis: 87.7% of laboratories reported routinely performing C. difficile diagnostic tests. Methods used included toxin detection (93%), culture (55%), and glutamate dehydrogenase (GDH) detection (5.9%). Among the laboratories detecting toxins, different enzyme immunoassays (EIA) and cytotoxicity assays were used in 79% and 17.3% of cases, respectively. Among the different strategies reported, 4.8% were considered suboptimal for the diagnosis of C. difficile infections, but marked discrepancies could be observed between countries. The overall incidence (median) of CDAD was estimated at 1.1 for 1,000 patient admissions. CONCLUSION: The results of this study suggest marked discrepancies between laboratories and also between countries regarding the criteria by which C. difficile is investigated for, and the methods and the strategies that are used for the diagnosis of C. difficile. These discrepancies could be explained by the lack of clear guidelines for C. difficile diagnosis in each country, and by the importance that physicians attach to C. difficile. Precise guidelines for C. difficile diagnosis would be the first step to make possible accurate comparison of the incidence and the epidemiology of CDAD from one hospital to another or from one country to another.

Decreased transmission of Enterobacteriaceae with extended-spectrum beta-lactamases in an intensive care unit by nursing reorganization.

In our gastrointestinal surgical intensive care unit (SICU), the large number of patients with multiple enterostomies enhances the risk of nosocomial transmission of gut extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBLE) by health care workers. A control study performed in our SICU from June-August 1992 showed an ESBLE gut colonization rate of 70%. To reduce this rate, nursing procedures were intensified or modified, particularly handwashing, single-use equipment and waste control. To test the efficiency of these procedures, 64 patients hospitalized for more than two days from September 1992-March 1993 were screened for gut acquisition of ESBLE. Rectal samples were taken within 48 h after admission and then weekly. After nursing reorganization, the ESBLE colonization rate dropped significantly to 40% (P < 0.001). Twenty patients (31.7%) acquired a gut ESBLE, after a mean of 24.3 +/- 13.7 days. Each patient was colonized with one, two or three ESBLE (Klebsiella pneumoniae, Escherichia coli and Enterobacter aerogenes). Baseline characteristics of the 20 colonized and 39 non-colonized patients showed no significant difference (Student's t-test, P > 0.05). The nursing workload, estimated as a omega index, was greater in the colonized group (P < 0.001). These findings show that strict observance of nursing procedures can significantly reduce ESBLE acquisition in a high-risk surgical unit.