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International audience; OBJECTIVE:The clinical characteristics and prognosis of patients treated for Candida peritonitis (CP) were compared according to the type of systemic antifungal therapy (SAT), empiric (EAF) or targeted (TAF) therapies, and the final diagnosis of infection.METHODS:Patients in intensive care units (ICU) treated for CP were selected among the AmarCAND2 cohort, to compare patients receiving EAF for unconfirmed suspicion of CP (EAF/nonCP), to those with suspected secondarily confirmed CP (EAF/CP), or with primarily proven CP receiving TAF.RESULTS:In all, 279 patients were evaluated (43.4% EAF/nonCP, 29.7% EAF/CP and 25.8% TAF patients). At SAT initiation, the severity of illness was similar among EAF/nonCP and EAF/CP patients, lower among TAF patients (median Simplified Acute Physiology Score II (SAPS II) 49 and 51 versus 35, respectively; p 0.001). Candida albicans was involved in 67%, Candida glabrata in 15.6%. All strains were susceptible to echinocandin; 84% to fluconazole. Echinocandin was administered to 51.2% EAF/nonCP, 49% EAF/CP and 40% TAF patients. At day 28, 72%, 76% and 75% of EAF/nonCP, EAF/CP and TAF patients, respectively, were alive. An increased mortality was observed in patients with a Sequential Organ Failure Assessment (SOFA) score

Resume Introduction La forme la plus frequente d'atteinte neurologique centrale a Mycoplasma pneumoniae est la meningoencephalite dont la frequence reste probablement sous-estimee. Objectifs Determiner de facon retrospective l'incidence des encephalites a M. pneumoniae parmi les autres cas d'encephalites diagnostiques dans les services concernes (infectiologie, neurologie, reanimation) du CHU en 2004 et 2005. Patients et methode Les criteres d'inclusion etaient des signes d'encephalopathie (troubles de la vigilance et/ou du comportement) associes a au moins un des signes suivants : fievre, deficit neurologique, crise comitiale, meningite, signes d'imagerie ou electroencephalographiques. Les causes evidentes diagnostiquees lors du scanner initial (hematome, metastases…) etaient exclues de l'etude. M. pneumoniae etait considere comme l'agent causal en cas de positivite des IgM en Elisa et/ou en cas de PCR positive dans le LCR. Resultats Quarante-huit encephalites dont 4 (8,3 %) attribuees a M. pneumoniae etaient recensees. Tous sauf un avaient une crise comitiale inaugurale. L'atteinte pulmonaire etait retrouvee deux fois. Tous ont recu tardivement un traitement specifique. Dans deux cas, l'antibiotherapie a paru avoir un impact sur l'evolution. Ces quatre cas sont survenus de novembre 2004 a aout 2005 dans un contexte epidemique : 48 adultes hospitalises ont eu une serologie positive a M. pneumoniae en 2005 contre 15 en 2004 sans augmentation du nombre de serologies demandees. Conclusions M. pneumoniae est une cause de meningoencephalite a rechercher notamment en cas de bilan etiologique initial negatif, de manifestations respiratoires associees et en periode epidemique. Un traitement presomptif de meningoencephalite devrait comprendre un antibiotique actif sur ce germe.

Resume Objectifs : Expliquer l'amelioration des echanges gazeux observee en decubitus ventral (DV) au cours du syndrome de detresse respiratoire aigue (SDRA). Rechercher l'existence d'une relation entre le volume des secretions bronchiques aspirees et l'amelioration des rapports PaO2/FIO2 observee en decubitus ventral, avec ou sans NO. Type d'etude : Etude prospective realisee entre mars 1998 et fevrier 1999. Patients : Quinze patients hospitalises en reanimation avec un SDRA (PaO2/FIO2 2,5). Methodes : Tous ont beneficie de 4 heures de DV (h0–h4) auquel on a associe une heure de NO inhale a la concentration inspiratoire de 5 ppm (entre h2 et h3). Les aspirations, pratiquees selon un rythme horaire entre h-2 et h6, ont ete pesees sur une balance de precision a partir de h-1. Des gazometries et un recueil des parametres hemodynamiques ont ete realises a h0, h2, h3, h4 et h6. Resultats : Le DV et l'association DV + NO ont entraine respectivement a h2 et h3 une amelioration des rapports PaO2/FIO2 de 102 ± 62 % et 156 ± 79 % par rapport a h0 (P 10 %). Il persistait 2 heures apres le retournement une amelioration significative de l'oxygenation de 42 %. Pour ce qui est des secretions, on a recueilli 3,0 ± 7,5 g, 4,4 ± 6,1 g, 1,7 ± 1,4 g et 1,7 ± 1,6 g entre h-2 et h0, h0 et h2, h2 et h4, h4 et h6, sans correlation au cas par cas avec l'evolution des rapports PaO2/FIO2 aux differents temps. Six patients ont eu des secretions inferieures a 1g entre h0 et h2, pour lesquels le gain en oxygenation s'est avere superieur a la moyenne (115 ± 53 % a h2). Conclusion : Chez ces malades peu ou moyennement secretants, l'amelioration de l'oxygenation observee, avec ou sans NO, ne depend pas de l'importance du drainage bronchique.

Resume Objectif Evaluer la tolerance et l'efficacite du nouvel antivenin Viperfav™, administre par voie IV pour traiter les envenimations par viperes europeennes. Type d'etude Essai therapeutique multicentrique ouvert, avec suivi d'une cohorte de patients traites par l'antivenin. Patients L'etude a porte sur 46 patients des deux sexes, adultes ou enfants, presentant une envenimation viperine en cours d'aggravation ou severe (grade 2 ou 3). Methode Des l'inclusion, les patients ont recu une perfusion de Viperfav™. Selon l'evolution, jusqu'a quatre perfusions espacees de 4 heures pouvaient etre administrees. Pour evaluer la tolerance, tout evenement a ete collecte. Pour l'efficacite, trois criteres objectifs (duree d'hospitalisation, evolution du grade, guerison [sequelle] et un critere subjectif (benefice de l'antivenin selon l'investigateur) ont ete choisis. Resultats Au total, 79 perfusions d'antivenin ont ete realisees; six evenements benins ont ete attribues au produit; aucun evenement severe n'a ete observe. La duree d'hospitalisation a ete de 4 jours 19 h ± 13 h. Le grade de severite s'est ameliore d'au moins un point pour 35 patients; tous ont quitte l'hopital sans sequelle. Selon les investigateurs, le produit n'a pas apporte de benefice a deux patients de grade 3, avec des lesions tissulaires installees. Conclusions La litterature faisant etat de 5 a 10 % de reactions severes aux autres antivenins, la tolerance du Viperfav™ IV peut etre consideree comme bonne. Tous les criteres d'evaluation etant en faveur d'une bonne efficacite, nous recommandons l'utilisation de Viperfav™ IV pour les envenimations de grade 2 et 3, a la place de l'actuel antivenin, moins purifie et utilisable uniquement par voie IM.

To determine the efficacy and side effects of prone positioning (PP) and nitric oxide (NO) inhalation, alone, associated, or combined with i.v. almitrine for the treatment of hypoxaemia in severe acute respiratory distress syndrome (ARDS).Over a period of 20 months, 27 consecutive critically ill patients with severe ARDS (Murray score2.5, PaO2/FiO2170 after alveolar recruitment) were prospectively and randomly included. They inhaled NO for two hours at concentrations of 5 and 10 ppm for one hour each (H0-H2). One hour later, they were returned to the prone position for four hours (H3-H7). During the last two hours in this position (H5-H7), they were assigned to further inhalation of 10 ppm NO (Group B, n = 9) or to no further inhalation (Group A, n = 9). In group C (n = 9), the procedure for group B was combined with perfusion of 16 mg.kg-1.min-1 almitrine throughout the study.Compared with control values, two hours NO inhalation improves PaO2/FiO2 and shunt effect by +28% and -9%, PP by +88% and -27%, PP + almitrine by +132% and -28%, NO + almitrine by +153 and -28%, PP + NO by +94% and -29%, NO + PP + almitrine by +327 and -48%. NO inhalation reduces pulmonary vascular resistance. Other haemodynamic parameters remain unchanged, whatever the treatment. NO inhalation improves PaO2/FiO2 by over 20% in 50% of the patients and PP is effective in 78% of the cases.Prone Position improves PaO2/FiO2 significantly more than NO alone but less than PP + almitrine or NO + almitrine. The best results are obtained with the association of NO + Prone position + Almitrine.

Enterobacter aerogenes strains resistant to imipenem were isolated in 10 patients, 7 of whom had received imipenem-cilastatin. The strains were differentiated by biotype, antibiotype, and plasmid content. All of the strains overproduced a chromosomal cephalosporinase and lost a major outer membrane protein with a size of about 40 kDa. In 5 of the 10 patients, E. aerogenes strains resistant to extended-spectrum cephalosporin were isolated during the same stay. In three patients, the similarity between the imipenem-susceptible and -resistant strains suggests the occurrence of mutation and reversion in vivo. The combination imipenem-cilastatin has been critically important for use with multiresistant strains of Enterobacter spp., but its use increases the risk of selection of imipenem-resistant strains.

We report the case of a 37-year-old woman who survived from severe hypothermia (rectal temperature: 22 degrees C) and prolonged cardiac arrest with asystole after benzodiazepine and tricyclic antidepressant poisoning. Basic-cardiopulmonary resuscitation and mechanical ventilation was started by a French Mobile Intensive-Care unit. Spontaneous circulation was restored at 25 degrees C under epinephrin after three hours of chest compression from home to the intensive-care unit and rewarming with extracorporeal circulation. The patient was discharged at day 13 without any neurological deficit. The discussion focuses on the benefit of extracorporeal-membrane oxygenation (ECMO) as extracorporeal circulation device through femoral access, the differential diagnosis between death and recoverable cardiac arrest and neuroprotection.

Meningoencephalitis is the most common central nervous system complication caused by Mycoplasma pneumoniae. Its frequency is probably underestimated.The study's aim was to determine the retrospectively incidence of M. pneumoniae meningoencephalitis among other cases of encephalitis diagnosed in infectiology, neurology and ICU at the Clermont-Ferrand University hospital in 2004 and 2005.A case of meningoencephalitis was defined by encephalopathy (altered level of consciousness and/or change in personality), with one or more of the following symptoms: fever, seizure, focal neurological findings, meningitis, electroencephalography or neuroimaging findings consistent with encephalitis. Tumor and hematoma diagnosed by scan were excluded. M. pneumoniae was considered as a possible cause when patients had positive serological test (IgM Elisa) and/or positive PCR results for the CSF.Four (8.3%) patients among 48 cases of encephalitis could have been caused by M. pneumoniae. All except one convulsed initially. Pneumopathy was found in two patients. All received a specific treatment later. Antibiotics seemed to influence evolution in only two patients. These 4 cases appeared during an epidemic between November 2004 and August 2005: 48 hospitalized adults had positive serological test for M. pneumoniae in 2005 and 15 in 2004, whereas the number of tests was the same in 2004 and in 2005.M. pneumoniae should be investigated as a cause of meningoencephalitis if initial tests are negative, if patients have respiratory symptoms and in case of epidemic. Presumptive treatment of meningoencephalitis should include an antibiotic active against M. pneumoniae.

This prospective, single centre, randomised, cross-over study compares patient tolerance of the facemask and mouthpiece for delivery of non-invasive ventilation in an intensive care unit. Twenty-seven patients with acute respiratory failure were scheduled for two 45-min sessions of non-invasive ventilation with facemask and mouthpiece. The order of the sessions was chosen at random. Nurses and patients assessed the tolerance of both techniques using a visual analogue scale. The time spent by nurses and the changes in respiratory parameters were recorded. The facemask was better tolerated than the mouthpiece; all the cases of non-invasive ventilation withdrawal (n = 5) occurred with mouthpieces (p = 0.026). Less nursing time was required using the facemask for the 22 patients who underwent both procedures (p = 0.01). However, the difference in tolerance scores was not significant. Non-invasive ventilation with both facemask and mouthpiece improved the P a O 2 /F i O 2 ratio, increased the pH and decreased the P a CO 2 . Only non-invasive ventilation with the facemask lowered the respiratory rate. The facemask appears to be a better initial choice for non-invasive ventilation when compared to mouthpiece, but both can be effective.

A bronchial secretion draining effect is frequently suggested as a mechanism for oxygenation improvement during prone positioning (PP) in patients with acute respiratory distress syndrome (ARDS). Nevertheless, it has never really been evaluated. The aim of this study was to search for an interrelationship between the volume of the bronchial secretion and the improvement of the PaO2/FIO2 ratio during prone positioning, with NO inhalation or not.Open prospective clinical study.The study included 15 consecutive patients with severe ARDS (PaO2/FIO2200 after alveolar recruitment, Murray score2.5).They were returned to the prone position for 4 hours (h0-h4) combined with an inhalation of 5 ppm NO during 1 hour (h2-h3). Tracheal suction were performed hourly between h-2 and h6 and weighed on a precision scale from h-1 to h6. Haemodynamic, blood gas and respiratory compliance were recorded at h0, h2, h3, h4 and h6.No significant haemodynamic changes were observed in the various phases. Compared with the baseline condition at h0, PP and PP + NO respectively improved PaO2/FIO2 by 102 +/- 62% at h2 (P0.005) and 156 +/- 79% at h3 (P0.005/h0 and0.01/h2). 14/15 patients responded to PP and 15/15 to PP + NO (gain in PaO2/FIO210%). Concerning secretions, we collected 3.0 +/- 7.5 g, 4.4 +/- 6.1 g, 1.7 +/- 1.4 g and 1.7 +/- 1.6 between h-2 and h0, h0 and h2, h2 and h4, h4 and h6. Individual assessments showed no relationship between the PaO2/FIO2 evolution at any time and the quantity of secretions obtained during the first 2 hours in the prone position. Six patients presented secretions of less than 1 g between h0 and h2, and for whom the improvement in oxygenation was higher than average (115 +/- 53% at h2).In patients with little or moderate secretions, the improvement observed in oxygenation, with or without NO, does not depend on their volume.

A case of nosocomial meningitis due to a Klebsiella pneumoniae producing a CAZ-5 extended-spectrum beta-lactamase and an Enterobacter aerogenes producing a derepressed cephalosporinase is reported. The intrathecal catheter incriminated was removed and a treatment with ceftazidime (4 g/24 h) and amikacin (1.5 g/24 h) was started. After 24 h ceftazidime was replaced by imipenem (2 then 4 g/24 h). This treatment failed to obtain cerebrospinal fluid sterilization; therefore the imipenem dosage was increased to 8 g/24 h and two intrathecal infusions of amikacin (50 mg) were carried out. Thereafter the patient recovered.

A fifteen-year-old girl, with a clean medical history, was admitted to the intensive care unit 90 minutes after ingestion of 2.5 g potassium cyanide. She had typical signs of severe cyanide poisoning including deep coma, circulatory failure, and major metabolic acidosis. Gastric lavage and antidotal treatment with 4 g hydroxocobalamin and 8 g sodium hyposulfite was administered without delay together with supportive treatment consisting of mechanical ventilation with FIO2, blood alkalinisation and administration of beta-stimulants. These measures led to a rapid clinical improvement. The ventilatory support was discontinued after 24 hours and the patient left the intensive care unit on the fourth day with only slightly impaired mental status. She survived despite a very high blood cyanide concentration (494 mumol.l-1 on admission) probably because of the rapid symptomatic and antidotal treatment.

To evaluate the tolerance and the effectiveness of i.v. Viperfav, a new antivenom containing F(ab')2 fragments of equine antibodies, for the treatment of European viper envenomed patients.Open, multicentre field trial, associated with a cohort study.The study included 46 patients of either gender, nine aged less then 10 years, eight between 10 and 15 years, and 28 adults, who sustained a moderate or severe viper envenomation (Grade 2 or 3).At the inclusion, a single infusion of Viperfav was given. Depending on the clinical course, up to four additional infusions were to have been administered at 4-hour intervals. To evaluate tolerance, all symptoms were recorded. There were three effectiveness evaluation criterion (duration of hospitalisation, course of the severity grade, recovery (sequelae)) and one subjective criteria (value of the antivenom as ascertained by investigators).In the 46 included patients, 79 infusions were administrated. Concerning tolerance, six mild symptoms were associated to the antivenom infusions. No severe reaction occurred. The mean duration of hospitalisation was 4 days 19 hours +/- 13 hours. A severity grade decrease by at least one point was observed in 35 patients, and all were discharged without sequelae. For the investigators the antivenom was inefficient in only two patients (grade 3 with tissue lesions).In comparison with literature data (5 to 10% of severe reactions attributable to the antivenom), the tolerance of Viperfav can be considered as satisfactory. As all criteria were in favour of a positive benefit to risk ratio, the authors recommend the use of Viperfav i.v. for the grade 2 and 3 envenomations instead of the current less purified antivenom, which can only be administered by the intramuscular route.

To study the effect of selective digestive tract decontamination by erythromycin-base on the incidence of carriage and infection with MR Enterobacteriaceae producing an extended spectrum beta-lactamase (ESB).After a 10-week prospective survey to ascertain the baseline incidence in two bays (1 and 3) of the same ICU, bay 1 was compared with bay 3 during a further survey of 6 months. The patients in bay 1 received erythromycin-base.Two non-contiguous bays, 1 and 3, of 4 beds, in the same polyvalent ICU of a university hospital.Consecutive patients with unit stay longer than 2 days; 34 patients were included during the control period, 43 in bay 1 (decontamination) and 46 in bay 3 (control) during the trial period.Erythromycin-base, 1 g t.i.d. in powder form administered by gastric tube to patients in bay 1 from admission to discharge.Digestive tract carriage was monitored by cultures of gastric and rectal swab specimens, sampled twice a week. Enterobacteriaceae were isolated on Drigalski agar with incorporated ceftazidime (4 mg/l). In bay 1 there was a decrease in ESB producing Enterobacteriaceae (23% vs 10%, p = 0.0004) from rectal swab, especially in K. pneumoniae (15% vs 2%, p = 10(-5)), during the decontamination period in comparison to the control period. During the trial period the only differences observed between bays 1 and 3 were in the gastric samples: K. pneumoniae were less often isolated in bay 1 than in bay 3 (0% vs 3%, p = 0.03). Intestinal carriage with multiresistant Enterobacteriaceae occurred in 28% patients in bay 1 and 30% patients in bay 3 during the trial period (p = 0.79). Erythromycin-base did not delay the carriage by patients in bay 1 (log rank test p = 0.42).Erythromycin-base was not effective in preventing digestive tract carriage due to Enterobacteriaceae resistant to third generation cephalosporin by production of chromosomal cephalosporinase. The decrease in isolates containing K. pneumoniae in bay 1 cannot be definitively attributed to erythromycin-base, since the number of this species in bay 3 was low.

Summary A 69-year-old woman was admitted to the hospital with meningitis due to Streptococcus pneumoniae. The strain was susceptible to penicillin but intermediate to cefotaxime. In Europe the decrease of susceptibility generally pertains more to penicillin than to cefotaxime. Such a strain is perhaps a forewarning of the existence of high-level cephalosporin-resistant strains. Despite the possible detection of the resistance by oxacillin disk, it underlines the need to determine the MICs of different beta-lactams without delay and to choose the most efficient treatment.

In July 1984 Klebsiella pneumoniae producing beta-lactamase CTX-1(TEM-3) (K. pneumoniae-CTX-1) spread from an Intensive Care Unit (ICU) throughout the hospitals of Clermont-Ferrand, France, and were isolated in four other hospitals of the region. A retrospective case control study was conducted in the ICU to characterize the risk factors for nosocomial infection with this organism. The cases were the 74 patients who had had K. pneumoniae-CTX-1 isolated from one or more clinical samples between July 1984 and December 1987. They were compared with 74 controls for host risk factors, underlying disease, procedures and antibiotic treatment. The monthly incidence of infection/colonization varied from 0% to 14.6%. The mortality rate attributable to this organism was 0.26% during the study period. The duration of stay of cases was longer than that of controls. More cases than controls had ventilatory assistance. However, the predominant risk factor was emergency abdominal surgery. Before K. pneumoniae-CTX-1 was isolated, cases received quinolones and trimethoprim sulphamethoxazole more often than controls. However, only 15% of cases had received third generation cephalosporins while at the onset of K. pneumoniae-CTX-1 infection colonization, 32 patients were no longer being given antibiotics. The use of antibiotic prophylaxis by, for example, selective digestive tract decontamination should be considered in patients at high risk of infection.

A fifteen-year-old girl, with a clean medical history, was admitted to the intensive care unit 90 minutes after ingestion of 2.5 g potassium cyanide. She had typical signs of severe cyanide poisoning including deep coma, circulatory failure, and major metabolic acidosis. Gastric lavage and antidotal treatment with 4 g hydroxocobalamin and 8 g sodium hyposulfite was administered without delay together with supportive treatment consisting of mechanical ventilation with FIO2, blood alkalinisation and administration of beta-stimulants. These measures led to a rapid clinical improvement. The ventilatory support was discontinued after 24 hours and the patient left the intensive care unit on the fourth day with only slightly impaired mental status. She survived despite a very high blood cyanide concentration (494 mumol.l-1 on admission) probably because of the rapid symptomatic and antidotal treatment.

The antiphospholipid syndrome produces acute occlusions of arteries and veins. This syndrome can cause a multiple organ systems failure whose outcome is often fatal. The authors report a case of the primary, antiphospholipid syndrome characterized by this fatal outcome, a so-called "devastating" syndrome following pulse steroids. In this patient, the antiphospholipid antibodies had been found after presenting bone-marrow fat necrosis, which led to extensive lesions of knees, hips and shoulders. Damage to the cell membranes in necrotic lesions might have promoted the immune response against phospholipids. The potential risks of pulse doses of steroids in the antiphospholipid syndrome are documented by the present observation, which also suggests that antiphospholipid antibodies should be determined in cases of fat necrosis of all origins.

The index studied (simplified acute physiology score, or SAPS) is calculated from 14 measurable clinical and laboratory data obtained during the first 24 hours from admission. It was tested in a prospective study involving 280 consecutive patients treated in a 16-bed intensive care unit. Good correlations were found between SAPS and mortality rate and between SAPS and the two most widely used scoring systems: the Knaus index or APS (acute physiology score) and the Cullen index or TISS (therapeutic intervention scoring system), both evaluating therapeutic effectiveness. SAPS data being easy to collect, the simplified index could be used in many intensive care units or even applied to old case-records. Its main value lies in comparisons between two groups of patients with the same death probability and in evaluations of activities in intensive care units.

From Summer 1983 to Summer 1986, 34 cases of septicemia due to Pseudomonas cepacia could be detected in several intensive care units in the university hospital in Clermont-Ferrand (France). Intravascular catheters can be involved in the inoculation of this bacterial agent: a previous respiratory tract infection or a drained abscess can be the portal of entry of the bacteremia. Three patients died from the septicemia and the overall prognosis of the intensive care patients looks significatively worsened. The removing of the catheters and drains, the opening of an infected collection were useful but not sufficient to overcome. The choice of a good antibiotic was not easy; only ceftazidime, minocycline and cotrimoxazole have a fair activity in vitro. We only assessed the good results of ceftazidime. Pseudomonas cepacia is also resistant for many antiseptics. The large use of disinfecting procedures in intensive care units promotes the diffusion of this bacteria.

L’evaluation du pronostic des victimes de traumatismes crâniens graves (TCG) est difficile dans la prise en charge de ces patients. Devant la faible sensibilite du score de Glasgow, la proteine S100B semble etre un bon marqueur pronostique. Cependant peu d’etudes sont basees sur des prelevements centraux en jugulaire. L’objectif de notre etude est de comparer l’interet de cinetiques arterielles et jugulaires des concentrations seriques de S100B chez le patient victime d’un TCG. Pour cela, nous avons mene une etude prospective au sein du CHU de Clermont-Ferrand, sur 17 patients orientes en service de reanimation suite a un TCG, dans le but d’evaluer l’interet d’une cinetique de dosages seriques de la proteine S100B en arteriel et en jugulaire au decours de leur prise en charge. Le dosage de la proteine S100B a demontre une concentration mediane de 0,16 μg/L en arteriel et de 0,25 μg/L en jugulaire. Pour l’ensemble des prelevements des 17 patients, la mediane de concentration arterielle en S100B est significativement differente de la mediane de concentration jugulaire. Cette difference significative arterio-jugulaire n’est pas retrouvee dans le sous-groupe des TCG de mauvaise evolution ni dans le sous-groupe des prelevements realises avant les 24 premieres heures post traumatisme. Dans le sous-groupe des TCG de mauvais pronostic, il n’existe pas, contrairement a ce que l’on observe en arteriel, de diminution significative du taux jugulaire de S100B apres les 24 premieres heures post traumatisme. En regard de ces resultats, les dosages en jugulaire semblent donc presenter un meilleur interet pronostique qu’en arteriel.

Introduction Preventing carriage of potentially pathogenic micro-organisms from the aerodigestive tract is an infection control strategy used to reduce the occurrence of ventilator-associated pneumonia in intensive care units. However, antibiotic use in selective decontamination protocols is controversial. The purpose of this study was to investigate the effect of oral administration of a probiotic, namely Lactobacillus, on gastric and respiratory tract colonization/infection with Pseudomonas aeruginosa strains. Our hypothesis was that an indigenous flora should exhibit a protective effect against secondary colonization. Methods We conducted a prospective, randomized, double-blind, placebo-controlled pilot study between March 2003 and October 2004 in a 17-bed intensive care unit of a teaching hospital in Clermont-Ferrand, France. Consecutive patients with a unit stay of longer than 48 hours were included, 106 in the placebo group and 102 in the probiotic group. Through a nasogastric feeding tube, patients received either 109 colony-forming units unity forming colony of Lactobacillus casei rhamnosus or placebo twice daily, from the third day after admission to discharge. Digestive tract carriage of P. aeruginosa was monitored by cultures of gastric aspirates at admission, once a week thereafter and on discharge. In addition, bacteriological analyses of respiratory tract specimens were conducted to determine patient infectious status. Results The occurrence of P. aeruginosa respiratory colonization and/or infection was significantly delayed in the probiotic group, with a difference in median delay to acquisition of 11 days versus 50 days (P = 0.01), and a nonacquisition expectancy mean of 69 days versus 77 days (P = 0.01). The occurrence of ventilator-associated pneumonia due to P. aeruginosa in the patients receiving the probiotic was less frequent, although not significantly reduced, in patients in the probiotic group (2.9%) compared with those in the placebo group (7.5%). After multivariate Cox proportional hazards modelling, the absence of probiotic treatment increased the risk for P. aeruginosa colonization in respiratory tract (adjusted hazard ratio = 3.2, 95% confidence interval – 1.1 to 9.1). Conclusion In this pilot study, oral administration of a probiotic delayed respiratory tract colonization/infection by P. aeruginosa. Trial registration The trial registration number for this study is NCT00604110.