Biofilm Assessment and Metagenomic Analysis of Venoarterial Extracorporeal Membrane Oxygenation Cannulas and Membrane Oxygenators

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) exposes the patient to infectious complications related to the cannulas or the site of insertion. The aim of the current study was to investigate and compare the prevalence of cannula and membrane oxygenators colonization using three different methods: microbiological culture, scanning electron microscopy, and metagenomic (rRNA 16S analysis). A monocentric prospective study was conducted between December 2017 and June 2018. Consecutive patients undergoing VA-ECMO support for refractory cardiac arrest or cardiogenic shock were included. Ten patients were included with a median age of 64 (52-62) years. Venoarterial extracorporeal membrane oxygenation was inserted for refractory cardiac arrest in five (50%), cardiogenic shock in four (40%), and self-poisoning in one (10%) cases. Microbiological culture of all (8/8, 100%) membrane oxygenators was negative, whereas all (10/10, 100%) were colonized by biofilm, and eight (8/9, 89%) presented bacterial DNA. Three (3/9, 33%) arterial and venous cannulas were positive in culture and seven (7/9, 78%) were colonized by biofilm, respectively. Seven (7/9, 78%) arterial and four (4/9, 44%) venous cannulas presented bacterial DNA. Colonization of cannulas and membranes is more frequent when assessed by electron microscopy or metagenomic analysis than with culture. Membrane oxygenators are more often colonized than cannulas.

Impact of Subarachnoid Hemorrhage in Ventriculostomy-Related Infections Prospective Comparison of Two Neurosurgical Injury Contexts

BACKGROUND

Long thought to be immune privileged, the central nervous system is far from being devoid of local immunity. Subarachnoid hemorrhage (SAH) and traumatic brain injury represent 2 distinct central nervous system injury situations which, while both exposed to external ventricular drains, present different incidences of ventriculostomy-related infection (VRI). We sought to compare VRI incidence and initial cerebrospinal fluid (CSF) inflammatory profiles in these 2 clinical situations.

METHODS

From 2015 to 2020, 227 patients treated for SAH (193) or traumatic brain injury (34) with an external ventricular drain were prospectively included. CSF samples were sent daily for microbiological examination, cell count, and biochemical analysis. VRI was defined as a positive CSF culture associated with CSF profile modifications and clinical signs. Ventriculostomy-related colonization was defined as positive catheter culture at removal. Positive events were defined as VRI and/or ventriculostomy-related colonization.

RESULTS

Eleven patients suffered from VRI, with an incidence of 3.6 VRI per 1000 catheter-days. All VRIs occurred among SAH patients without a significant difference. Median duration of drainage was 12 (7-18) days, there were no significant differences for known VRI risk factors. Positive events were significantly higher in SAH patients (20.7% vs. 2.9%, P = 0.013). Inflammatory CSF markers and serum white blood cells were higher in SAH patients.

CONCLUSIONS

Local inflammatory markers were markedly higher in SAH than in traumatic brain injury. However, positive events were more frequent in SAH. Furthermore, SAH may be a risk factor for VRI. Hypothesis that a primary injury to the subarachnoid space could impair central nervous system immune functions should be explored.

Prospective Comparative Study of External Ventricular Drain Catheter Colonization: Antibiotic-Impregnated versus Conventional Drains

OBJECTIVE

Our aim was to compare the prevalence of biofilm formation on antibiotic-impregnated (AIC) versus standard (SC) external ventricular drain (EVD) catheters.

METHODS

From March 2018 to November 2020, all consecutive EVD catheters inserted in adult patients were included. After removal, EVD catheters were analyzed under scanning electronic microscopy, on both extraluminal and intraluminal faces. Standard culture of catheter tips was also performed.

RESULTS

Overall, 114 catheters were included in 101 patients. There were 48 AICs and 66 SCs. Standard culture showed that ventriculostomy-related colonization was more frequent in SC than in AIC (26 vs. 10%; P = 0.06). Gram-negative rods accounted for 25% of ventriculostomy-related colonization in AICs, and none was documented in SCs. Scanning electronic microscopy observation showed mature biofilm on more than 80% of catheters, without significant difference between catheter type. Also, there was no difference between extraluminal and intraluminal colonization rate. There were 2 ventriculostomy-related infections in each group (5% and 3% among AICs and SCs respectively; P = 1).

CONCLUSIONS

Mature biofilm presence on the intraluminal and the extraluminal faces is similar on AICs and SCs. Accordingly, AICs do not seem to efficiently prevent biofilm formation on EVD catheters. The impact of AICs on the microbiological epidemiology of colonizing biofilm should be further evaluated.

Antimicrobial Susceptibility of Community-acquired Urine Bacterial Isolates in French Amazonia

Bacterial resistance in community-acquired urinary tract infections (UTIs) is increasing worldwide. Our study aimed to assess the microbiological epidemiology and antimicrobial susceptibility patterns of community-acquired urine bacterial isolates in French Amazonia. Our study is retrospective. It was conducted from January 2015 to December 2019 in the microbiology laboratory of the Cayenne General Hospital (French Guiana). It includes all positive urine samples from adult (> 18 years) outpatients (N = 2,533). Isolated microorganisms were Gram-negative rods in 83.9%, mainly Enterobacterales (98.4%). The main isolated bacteria were Escherichia coli (58.7%) and Klebsiella pneumoniae (13.3%). Among the isolated E. coli, 37.2% were susceptible to amoxicillin, 77.9% to amoxicillin/clavulanic acid, 94.9% to cefotaxime, 78.9% to ofloxacin, and 98.9% to nitrofurantoin. In 106 cases (5.1%), isolated Enterobacterales were extended-spectrum β-lactamase producers (5% of E. coli and 8.9% of K. pneumoniae). Overall, high levels of cross- and co-resistance were registered. The main isolated Gram-positive bacteria was Staphylococcus saprophyticus (28.9%). It was resistant to oxacillin in 52.5% of cases and susceptible to nitrofurantoin in 99.1% of cases. Patients with S. saprophyticus were young women in almost all cases. In conclusion, the most isolated microorganisms from outpatient urinalyses were E. coli and K. pneumoniae. They showed a high resistance rate to amoxicillin, but they were susceptible to the most remaining antibiotics. S. saprophyticus was isolated mainly in young women and was resistant to oxacillin in half of the cases. Interestingly, nitrofurantoin was active against most isolated organisms and can be considered as empirical treatment in uncomplicated UTIs.

Clinical outcome of wild-type AmpC-producing Enterobacterales infection in critically ill patients treated with β-lactams: a prospective multicenter study

Background

β-lactams are the main antibiotics used against wild-type AmpC-producing Enterobacterales (wtAE). However, they may fail or select AmpC-overproducing mutants. Our aim was to assess factors associated with clinical failure of β-lactams in the treatment of wtAE infection.

Methods

From September 2017 to December 2020, we prospectively included all consecutive patients treated by definitive β-lactams therapy for wtAE infection in four university ICUs. Clinical failure was defined as inadequate response to antimicrobial therapy leading to death or to the switch for a broader-spectrum antibiotic.

Results

177 patients were included and 29.4% progressed to clinical failure. E. cloacae was the most prevalent species (42.4%) and ventilator-associated pneumonia (VAP) was the most frequent wtAE infection (69.5%). Cefepime and cefotaxime were used as definitive antibiotic treatment in 42.9% and 27.7% of patients, respectively. Occurrence of AmpC-overproduction was documented in 5.6% of patients and was associated with clinical failure (p = 0.004). In multivariate analysis, VAP (p < 0.001, OR 11.58 [95% CI 3.11–43.02] and K. aerogenes (p = 0.030, OR 3.76 [95% CI 1.13–12.46]) were independently associated with clinical failure. Conversely, cefotaxime as definitive treatment was found inversely associated with the risk of clinical failure (p = 0.022, OR 0.25 [95% CI 0.08–0.82]). After inverse probability weighting, cefotaxime showed a 20% risk reduction of clinical failure (95% CI  5–35%, p = 0.007) whatever the location of infection, the SOFA score on the day of wtAE infection, or the bacterial species.

Conclusions

Clinical failure in the treatment of wtAE infections is associated with the infection site and the causal microorganism. Additionally, cefotaxime use is probably protective against clinical failure in wtAE infection.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-022-01079-5.

In-Flight Medical Emergencies Management by Anesthetist-Intensivists and Emergency Physicians

BACKGROUND: In-flight medical emergencies (IME) are challenging situations: aircraft cabins are noisy and narrow, medical supplies are scarce, and high-altitude related physiological changes may worsen chronic respiratory or cardiac conditions. The aim of this study was to assess the extent to which anesthetist-intensivists and emergency physicians are aware of IME specificities.METHODS: A questionnaire containing 21 items was distributed to French anesthetist-intensivists and emergency physicians between January and May 2020 using the mailing list of the French Society of Anesthesia and Intensive Care Medicine and the French Society of Emergency Medicine. The following topics were evaluated: high-altitude related physiological changes, medical and human resources available inside commercial aircraft, common medical incidents likely to happen on board, and previous personal experiences.RESULTS: The questionnaire was completed by 1064 physicians. The items corresponding to alterations in the arterial oxygen saturation, respiratory rate, and heart rate at cruising altitude were answered correctly by less than half of the participants (respectively, 3%, 42%, and 44% of the participants). Most responders (83%) were interested in a complementary training on IME management.DISCUSSION: The present study illustrates the poor knowledge in the medical community of the physiological changes induced by altitude and their consequences. In addition to offering specific theoretical courses to the medical community, placing sheets in commercial aircraft summarizing the optimal management of the main emergencies likely to happen on board might be an interesting tool.Diop S, Birnbaum R, Cook F, Mounier R. In-flight medical emergencies management by anesthetist-intensivists and emergency physicians. Aerosp Med Hum Perform. 2022; 93(8):633-636.

In vitro study of factors influencing the duration of antimicrobial protection of antimicrobial-impregnated external ventricular drains

BACKGROUND

In vitro and clinical studies assessing the duration of the protective activity of antimicrobial-impregnated external ventricular drains (AI-EVDs) gave conflicting results.

OBJECTIVES

To identify factors associated with decreased antimicrobial activity of AI-EVDs that were not taken into account in previous in vitro models.

METHODS

We performed in vitro experiments with Bactiseal™ AI-EVDs, under different conditions. Tested parameters were chosen to mimic conditions in which AI-EVDs are used: perfusion by saline (at different flow rates) or not perfused, dwelling medium (air, saline, saline+protein, lipid) and temperature. Antimicrobial activity was assessed by measurement of inhibitory diameters of a 0.5 cm portion of an AI-EVD (cut every 2 days) placed onto agar plates covered by a standardized Staphylococcus spp. inoculum (three different isolates). MS was used to measure concentrations of rifampicin and clindamycin after 48 h of dwelling.

RESULTS

In univariate analysis, most of the tested factors were associated with reduced antimicrobial activity: liquid media (as compared with ambient air), perfusion whatever the rate flow (as compared with no perfusion) and presence of protein in the media. In multivariate analysis, dwelling in media (lipid or saline) was the most constantly associated with a reduction of inhibition diameters (P < 0.01), as compared with ambient air. After 48 h of dwelling, the clindamycin concentration was higher than 100 and 450 mg/L in saline and saline+BSA, respectively.

CONCLUSIONS

The medium in which an AI-EVD is dwelling plays a significant role in the duration of AI-EVD activity. These results may explain conflicting results between clinical and in vitro studies.

Terror in Paris: Incidence and risk factors for infections related to high-energy ammunition injuries

BACKGROUND

We aimed to assess the incidence and the risk factors for secondary wound infections associated to high-energy ammunition injuries (HEAI) in the cohort of civilian casualties from the 2015 terrorist attacks in Paris.

METHODS

This retrospective multi-centric study included casualties presenting at least one HEAI who underwent surgery during the first 48 h following hospital admission. HEAI-associated infection was defined as a wound infection occurring within the initial 30 days following trauma. Risk factors were assessed using univariate and multivariate analysis.

RESULTS

Among the 200 included victims, the rate of infected wounds was 11.5%. The median time between admission and the surgical revision for secondary wound infection was 11 days [IQR 9-20]. No patient died from an infectious cause. Infections were polymicrobial in 44% of the cases. The major risk factors for secondary wound infection were ISS (p < 0.001), SAPS II (p < 0.001), MGAP (p < 0.001), haemorrhagic shock (p = 0.003), use of vasopressors (p < 0.001), blood transfusion (p < 0.001), abdominal penetrating trauma (p = 0.003), open fracture (p = 0.01), vascular injury (p = 0.001), duration of surgery (p = 0.009), presence of surgical material (p = 0.01). In the multivariate analysis, the SAPS II score (OR 1.07 [1.014-1.182], p = 0.019) and the duration of surgery (OR 1.005 [1.000-1.012], p = 0.041) were the only risk factors identified.

CONCLUSION

We report an 11.5% rate of secondary wound infection following high-energy ammunition injuries. Risk factors were an immediately severe condition and a prolonged surgery.

Suspicion of penetrating cardiac injury: Curing or caring?

Identifying penetrating cardiac injury in hemodynamically stable patients can be challenging especially when the patient has no signs of cardiac tamponade and no pericardial effusion identified on transthoracic echocardiography. In this case report, we discuss both penetrating cardiac injuries diagnosis algorithm and treatment strategies. At present, it is difficult to refer to general guidelines transposable from one center to another. We report the paramount importance of multidisciplinary management with experienced teams to face any possible pitfalls in traumatology especially in the context of penetrating cardiac injury.

Multidrug-Resistant Staphylococcus epidermidis Ventriculostomy-Related Infection Successfully Treated by Intravenous Ceftaroline after Failure of Daptomycin Treatment

BACKGROUND

Ventriculostomy-related infection with multidrug-negative strains are challenging to treat. We report the use of new antibiotics in such a case.

CASE DESCRIPTION

We report the case of a neurosurgical intensive care unit patient who developed ventriculostomy-related infection with a multidrug-resistant Staphylococcus epidermidis. Vancomycin, recommended in such cases, was not used due to high minimal inhibitory concentrations and concerns for lack of pharmacokinetic/pharmacodynamic target attainment. Daptomycin and ceftaroline remained the only treatment options. Daptomycin was shown microbiologically ineffective after 10 treatment days, with undetectable cerebrospinal fluid (CSF) concentration. Ceftaroline, a novel beta-lactam agent to which the strain showed susceptibility, was thus used. Serum and CSF samples were assessed for antibiotic concentrations. Our results show that CSF bacterial clearance was obtained after 6 days of such treatment. Serum and CSF samplings showed low penetration ratios (2.6%-4.8%), probably due to mild inflammatory CSF profile, with CSF concentration at minimal inhibitory concentration level.

CONCLUSIONS

We observed than even in the case of mild meningeal inflammation, ceftaroline penetration in CSF, although moderate, enabled efficient bacterial clearance and clinical efficacy, in adjunction to correct ventriculoperitoneal shunt management.

Durability of antimicrobial activity of antibiotic-impregnated external ventricular drains: a prospective study

Background

Antibiotic-impregnated external ventricular drains (AI-EVDs) have a debated efficacy in clinical studies.

Objectives

Our aim was to assess the durability of antimicrobial activity of AI-EVDs used in clinical settings.

Methods

From April 2017 to January 2018, all consecutive AI-EVDs (Bactiseal™) inserted in adult patients were prospectively included. After removal, each AI-EVD was cultured and assessed for antimicrobial activity on both internal and external sides of AI-EVDs. Catheters were each challenged with a single Staphylococcus strain [MSSA, MRSA or methicillin-resistant Staphylococcus epidermidis (MRSE)]. MS was used to measure residual concentrations of rifampicin and clindamycin.

Results

Sixty-five AI-EVDs were included (56 patients). Among these, 21 were challenged with MSSA, 23 with MRSA and 21 with MRSE. Five ventriculostomy-related colonizations (9%) and two ventriculostomy-related infections (4%) occurred. Staphylococcus was the main bacterium responsible for colonization (4/5). AI-EVD inhibition decreased significantly against MRSA and MRSE according to duration of catheterization (for external and internal sides, P < 0.02) and overall volume of CSF drained (P < 0.005 for both sides against MRSE, P < 0.005 for external side against MRSA), but not against MSSA. Clindamycin concentration was not correlated with duration of catheterization or CSF volume drained, but <20% of initial concentration was recovered even after 5 days of AI-EVD dwelling. Conversely, rifampicin concentration showed a rapid and significant decline correlated to duration and CSF volume (P < 0.001 and P = 0.03, respectively).

Conclusions

Antimicrobial activity of AI-EVDs dropped quickly in vivo. Antimicrobial impregnation did not prevent AI-EVD colonization by susceptible strains in 9% of the cases.

Prediction of Early Intracranial Hypertension After Severe Traumatic Brain Injury: A Prospective Study

OBJECTIVE

This study aimed to assess the reliability of clinical features, noninvasive transcranial Doppler-related pulsatility index (PI) calculation, and optic nerve sheath diameter (ONSD) measured by ultrasound (US) and initial computed tomography (CT) scan (Marshall CT scan classification) in predicting the occurrence of early (<24 hours) high intracranial pressure (EHICP) (>20 mm Hg) after severe traumatic brain injury (TBI).

METHODS

We conducted an observational prospective study in a level 1 trauma center. Patients were measured simultaneously for PI and US ONSD in the triage zone. Patients were categorized into 2 groups: those who had EHICP after TBI (EHICP+) and those who did not (EHICP-).

RESULTS

Fifty-four patients were included; 32 were categorized as EHICP+ and 22 as EHICP-. PI >1.4 did not correlate with EHICP+ patients (69% vs. 46%, P = 0.09). US ONSD measurement was higher in the EHICP+ group (6.25; range, 6-6.95 vs. 5.7; range, 5.2-6.4; P = 0.005). The area under the receiver operating characteristic curve for US ONSD as a predictor of developing EHICP was 0.73 (95% confidence interval [CI], 0.59-0.86). CT ONSD measurement was higher in the EHICP+ group (6.71; range, 6.35-7.87 vs. 6.25; range, 5.8-6.93; P = 0.04). The area under the receiver operating characteristic curve for CT ONSD measurement as a predictor for EHICP+ was 0.67 (95% CI, 0.53-0.81). The diffuse injury III and IV categories in the Marshall CT scan classification were associated with the occurrence of EHICP (P = 0.004).

CONCLUSIONS

None of the clinical features or noninvasive tools assessed in this study enabled clinicians to strictly ascertain EHICP. Further studies are needed to establish their potential role before intracranial pressure probe insertion.

Natural history of ventriculostomy-related infection under appropriate treatment and risk factors of poor outcome: a retrospective study

OBJECTIVEThe authors aimed to describe the natural history of ventriculostomy-related infections (VRIs) under appropriate treatment and to assess risk factors for poor outcome.METHODSAll patients older than 18 years in whom an external ventricular drain (EVD) had been implanted and who had developed a VRI requiring treatment were included in this retrospective study. D0 was defined as the first day of antibiotic administration. Clinical and biological parameters were compared each day beginning with D1 and ending with D10 to those of D0. The authors defined D0 in a control group as the day a CSF culture came back positive, without any sign of infection. The authors then searched for poor prognostic factors in the VRI group.RESULTSAmong 567 patients requiring an EVD between January 2007 and October 2017, 39 developed a VRI. Most were monomicrobial infections, and 47 microbes were responsible (45% were gram-positive cocci). Clinical parameters differed significantly from the control group during the first 2 days and then returned to baseline. The CSF parameters differed significantly from the control group for a longer period, returning to baseline after 5 days. CSF sterilization occurred in a median time of 2 days. An intrathecal route or EVD exchange was not associated with a poor outcome. No clinical or biological parameter between D3 and D5 was linked to outcome.CONCLUSIONSClinical status improved faster than CSF parameters (before and after D5, respectively). Some CSF parameters remained abnormal until D10. Body temperature and microbiological cultures normalized faster than other parameters.

Multidrug-Resistant Acinetobacter baumannii Ventriculostomy-Related Infection, Treated by a Colistin, Tigecycline, and Intraventricular Fibrinolysis

BACKGROUND

Acinetobacter baumannii meningitis and ventriculitis are difficult issues, because of the low diffusion of antibiotics in the cerebrospinal fluid and bacterial multidrug resistance. The presence of an infected intraventricular hematoma, constituting an equivalent of undrained abscess, may promote biofilm formation and failure of medical treatment.

CASE DESCRIPTION

In this case of ventriculostomy-related infection after ventricular hemorrhage, Acinetobacter baumannii was sensitive only to colistin and tigecycline. Despite a combination therapy involving intraventricular injections of colistin, we observed clinical and bacteriologic failure. Therefore, at day 4 of antibiotic therapy, we performed intraventricular fibrinolysis, which dissolved the clot, enabling sterilization of the cerebrospinal fluid after 48 hours.

CONCLUSION

This clinical case suggests the usefulness of intraventricular fibrinolysis to lyse the clot and optimize the action of antibiotics.

The multistep road to ventilator-associated lung abscess: A retrospective study of S.aureus ventilator-associated pneumonia

Object

We observed some cases of lung abscess (LA) in ICU patients suffering S.aureus ventilator-associated pneumonia (S.aureus-VAP). We aimed to assess which of the host and/or bacteria-related features are associated with LA.

Methods

We conducted a retrospective study from January 2009 to July 2013 in a trauma surgical ICU within a teaching hospital. All adult patients presenting with S.aureus-VAP were included. We compared two groups of patients according to the formation or not of LA concomitantly to S.aureus-VAP.

Results

Seventy-nine S.aureus-VAP patients, predominantly males (85%) of rather young age (mean [SD]: 35yr [21–64]) with severe trauma (initial Simplified Acute Score II = 42 [32–52]) related-ICU admission, were included. Among them, 10 (14%) developed LA. Patient’s characteristics significantly associated with LA development were: a younger age (p = 0.003), road traffic accidents admission (p = 0.017), head injury (p = 0.002), lower Glasgow Coma Scale (p = 0.009), blunt chest trauma (p = 0.01) pneumothorax (p = 0.01) and lung contusions (p = 0.002). No microbiological factors were significantly associated with LA formation. Abscesses were mostly bilateral, ≥5 cm of diameter and with a posterior location.

Conclusions

Our results do not favor a specific virulence of S.aureus, but rather highlight the role of multiple insults to the lung, promoting LA formation. Despite a similar severity score, patients with LA had more serious trauma, combining severe both chest and head insults.

Contribution of Ultra Deep Sequencing in the Clinical Diagnosis of a New Fungal Pathogen Species: Basidiobolus meristosporus

Some cases of fungal infection remained undiagnosed, especially when the pathogens are uncommon, require specific conditions for in vitro growth, or when several microbial species are present in the specimen. Ultra-Deep Sequencing (UDS) could be considered as a precise tool in the identification of involved pathogens in order to upgrade patient treatment. In this study, we report the implementation of UDS technology in medical laboratory during the follow-up of an atypical fungal infection case. Thanks to UDS technology, we document the first case of gastro-intestinal basidiobolomycosis (GIB) due to Basidiobolus meristosporus. The diagnosis was suspected after histopathological examination but conventional microbiological methods failed to supply proof. The final diagnosis was made by means of an original approach based on UDS. DNA was extracted from the embedded colon biopsy obtained after hemicolectomy, and a fragment encompassing the internal transcribed spacer (ITS) rDNA region was PCR-amplified. An Amplicon library was then prepared using Genome Sequencer Junior Titanium Kits (Roche/454 Life Sciences) and the library was pyrosequenced on a GS Junior (Roche/454 Life Sciences). Using this method, 2,247 sequences with more than 100 bases were generated and used for UDS analysis. B. meristosporus represented 80% of the sequences, with an average homology of 98.8%. A phylogenetic tree with Basidiobolus reference sequences confirmed the presence of B. meristosporus (bootstrap value of 99%).

Conclusion : UDS-based diagnostic approaches are ready to integrate conventional diagnostic testing to improve documentation of infectious disease and the therapeutic management of patients.

Is First-Line Vancomycin Still the Best Option to Treat Staphylococcus Health Care-Associated Meningitis?

BACKGROUND

Cerebrospinal fluid (CSF) penetration of vancomycin through the blood-brain barrier is poor but important inflammation improved it. Hence, vancomycin is recommended for the treatment of community meningitis. However, what about mild inflammatory health care-associated meningitis? The aim of this study was to evaluate the impact of vancomycin diffusion on CSF in Staphylococcus epidermidis health care-associated meningitis.

CASE DESCRIPTION

This was a retrospective study of all consecutive patients with S. epidermidis CSF shunt-associated infection, which was treated by continuous intravenous vancomycin after standard of care (60 mg/kg/d after a loading dose of 15 mg/kg). Patient outcome, CSF protein level, and vancomycin concentration in CSF and serum were assessed. We report 6 consecutives cases. Clinical and biologic manifestations were of mild intensity. Meningeal permeability was moderately altered with low CSF protein levels. Despite appropriate vancomycin dosage resulting in high serum concentrations, CSF remained below the S. epidermidis minimal inhibitory concentration.

CONCLUSIONS

We propose to reassess vancomycin use as first-line therapy when meningeal inflammation is mild-to-moderate in favor of antibiotics, which have a better CSF penetration.

Clinical, biological, and microbiological pattern associated with ventriculostomy-related infection: a retrospective longitudinal study

BACKGROUND

Our aim was to describe the pattern of ventriculostomy-related infection (VRI) development using a dynamic approach.

STUDY DESIGN

Retrospective longitudinal study.

METHODS

We analyzed the files of 449 neurosurgical patients who underwent placement of external ventricular drain (EVD). During the study period, CSF sampling was performed on a daily base setting. VRI was defined as a positive CSF culture resulting in antibiotic treatment. For VRI patients, we arbitrary defined day 0 (D0) as the day antibiotic treatment was started. In these patients, we compared dynamic changes in clinical and biological parameters at four pre-determined time points: (D-4, D-3, D-2, D-1) with those of D0. For all CSF-positive cultures, we compared CSF biochemical markers' evolution pattern between VRI patients and the others, considered as a control cohort.

RESULTS

Thirty-two suffered from VRI. Peripheral white blood cell count did not differ between D-4-D0. Median body temperature, CSF cell count, median Glasgow Coma Scale, CSF protein, and glucose concentrations were significantly different between D-4, D-3, D-2, and D0. At D0, 100 % of CSF samples yielded organisms in culture. The physician caring for the patient decided to treat VRI based upon positive CSF culture in only 28 % (9/32) of cases. In the control cohort, CSF markers' profile trends to normalize, while it worsens in the VRI patients.

CONCLUSIONS

We showed that clinical symptoms and biological abnormalities of VRI evolved over time. Our data suggest that VRI decision to treat relies upon a bundle of evidence, including dynamic changes in CSF laboratory exams combined with microbiological analysis.

From the Skin to the Brain: Pathophysiology of Colonization and Infection of External Ventricular Drain, a Prospective Observational Study

Ventriculostomy-related infection (VRI) is a serious complication of external ventricular drain (EVD) but its natural history is poorly studied. We prospectively tracked the bacteria pathways from skin towards ventricles to identify the infectious process resulting in ventriculostomy-related colonization (VRC), and VRI. We systematically sampled cerebrospinal fluid (CSF) on a daily basis and collected swabs from both the skin and stopcock every 3.0 days for microbiological analysis including in 101 neurosurgical patient. Risk factors for positive event defined as either VRC or VRI were recorded and related to our microbiological findings. A total of 1261 CSF samples, 473 skin swabs, and 450 stopcock swabs were collected. Skin site was more frequently colonized than stopcock (70 (60%) vs 34 (29%), p = 0.023), and earlier (14 ±1.4 vs 24 ±1.5 days, p<0.0001). Sixty-one (52%) and 32 (27%) skin and stopcock sites were colonized with commensal bacteria, 1 (1%) and 1 (1%) with pathogens, 8 (7%) and 1 (1%) with combined pathogens and commensal bacteria, respectively. Sixteen positive events were diagnosed; a cutaneous origin was identified in 69% of cases. The presence of a pathogen at skin site (6/16 vs 4/85, OR: 11.8, [2.5–56.8], p = 0.002) and CSF leakage (7/16 vs 6/85, OR 10 [2.4–41.2], p = 0.001)) were the two independent significant risk factors statistically linked to positive events occurrence. Our results suggest that VRC and VRI mainly results from an extra-luminal progression of pathogens initially colonizing the skin site where CSF leaks.

[Wound prevention in the surgical intensive care unit]

Literature reports a high prevalence of wounds in the hospital environment. A study devoted to wounds encountered in post-surgical intensive care has been carried out in a university hospital. This work highlighted the diversity of acute wounds mainly observed in intensive care and the difficulties nurses have in managing them.

Study of prone positioning to reduce ventilator-associated pneumonia in hypoxaemic patients

The aim of the present study was to examine whether prone positioning (PP) affects ventilator associated-pneumonia (VAP) and mortality in patients with acute lung injury/adult respiratory distress syndrome. 2,409 prospectively included patients were admitted over 9 yrs (2000-2008) to 12 French intensive care units (ICUs) (OUTCOMEREA). The patients required invasive mechanical ventilation (MV) and had arterial oxygen tension/inspiratory oxygen fraction ratios <300 during the first 48 h. Controls were matched to PP patients on the PP propensity score (+/-10%), MV duration longer than that in PP patients before the first turn prone, and centre. VAP incidence was similar in the PP and control groups (24 versus 13 episodes.1,000 patient-days MV(-1) respectively, p = 0.14). After adjustment, PP did not decrease VAP occurrence (HR 1.64 (95% CI 0.70-3.84); p = 0.25) but significantly delayed hospital mortality (HR 0.56 (95% CI 0.39-0.79); p = 0.001), without decreasing 28-day mortality (37% in both groups). Post hoc analyses indicated that PP did not protect against VAP but, when used for >1 day, might decrease mortality and benefit the sickest patients (Simplified Acute Physiology Score >50). In ICU patients with hypoxaemic acute respiratory failure, PP had no effect on the risk of VAP. PP delayed mortality without decreasing 28-day mortality. PP >1 day might decrease mortality, particularly in the sickest patients.

Model for predicting short-term mortality of severe sepsis

Introduction

To establish a prognostic model for predicting 14-day mortality in ICU patients with severe sepsis overall and according to place of infection acquisition and to sepsis episode number.

Methods

In this prospective multicentre observational study on a multicentre database (OUTCOMEREA) including data from 12 ICUs, 2268 patients with 2737 episodes of severe sepsis were randomly divided into a training cohort (n = 1458) and a validation cohort (n = 810). Up to four consecutive severe sepsis episodes per patient occurring within the first 28 ICU days were included. We developed a prognostic model for predicting death within 14 days after each episode, based on patient data available at sepsis onset.

Results

Independent predictors of death were logistic organ dysfunction (odds ratio (OR), 1.22 per point, P < 10^-4), septic shock (OR, 1.40; P = 0.01), rank of severe sepsis episode (1 reference, 2: OR, 1.26; P = 0.10 ≥ 3: OR, 2.64; P < 10^-3), multiple sources of infection (OR; 1.45, P = 0.03), simplified acute physiology score II (OR, 1.02 per point; P < 10^-4), McCabe score ([greater than or equal to]2) (OR, 1.96; P < 10^-4), and number of chronic co-morbidities (1: OR, 1.75; P < 10^-3, ≥ 2: OR, 2.24, P < 10^-3). Validity of the model was good in whole cohorts (AUC-ROC, 0.76; 95%CI, 0.74 to 0.79; and HL Chi-square: 15.3 (P = 0.06) for all episodes pooled).

Conclusions

In ICU patients, a prognostic model based on a few easily obtained variables is effective in predicting death within 14 days after the first to fourth episode of severe sepsis complicating community-, hospital-, or ICU-acquired infection.

AMP-activated protein kinase in the regulation of hepatic energy metabolism: from physiology to therapeutic perspectives

As the liver is central in the maintenance of glucose homeostasis and energy storage, knowledge of the physiology as well as physiopathology of hepatic energy metabolism is a prerequisite to our understanding of whole-body metabolism. Hepatic fuel metabolism changes considerably depending on physiological circumstances (fed vs. fasted state). In consequence, hepatic carbohydrate, lipid and protein synthesis/utilization are tightly regulated according to needs. Fatty liver and hepatic insulin resistance (both frequently associated with the metabolic syndrome) or increased hepatic glucose production (as observed in type 2 diabetes) resulted from alterations in substrates oxidation/storage balance in the liver. Because AMP-activated protein kinase (AMPK) is considered as a cellular energy sensor, it is important to gain understanding of the mechanism by which hepatic AMPK coordinates hepatic energy metabolism. AMPK has been implicated as a key regulator of physiological energy dynamics by limiting anabolic pathways (to prevent further ATP consumption) and by facilitating catabolic pathways (to increase ATP generation). Activation of hepatic AMPK leads to increased fatty acid oxidation and simultaneously inhibition of hepatic lipogenesis, cholesterol synthesis and glucose production. In addition to a short-term effect on specific enzymes, AMPK also modulates the transcription of genes involved in lipogenesis and mitochondrial biogenesis. The identification of AMPK targets in hepatic metabolism should be useful in developing treatments to reverse metabolic abnormalities of type 2 diabetes and the metabolic syndrome.

Effects of acute hypoxic exposure on prooxidant/antioxidant balance in elite endurance athletes

We investigated whether acute hypoxic exposures could modify the pro-oxidant/antioxidant balance in elite endurance athletes, known to have efficient antioxidant status. Forty-one elite athletes were subjected to two hypoxic tests: one at an altitude of 4 800 m during 10-min of mild exercise (4 800 m test) and the second at rest for 3 h at an altitude of 3 000 m (3 000 m test). Plasma levels of advanced oxidation protein products (AOPP), malondialdehydes (MDA), ferric reducing antioxidant power (FRAP) and lipid-soluble antioxidants were measured before and immediately after the 4 800 m test and at the end of the 3 000 m test. The 4 800 m and the 3 000 m tests induced a significant increase in the level of MDA and AOPP (+7.1% and +71.7% for 4 800 m test and +8.6% and +40.9% for 3 000 m test). The changes in plasma MDA and arterial oxygen saturations were significantly correlated (r=0.35) during the 3 000 m test. FRAP values (-13%) and alpha-tocopherol (-21%) were decreased following the 3 000 m test. However, following the 4 800 m test, only alpha-tocopherol was decreased (-16%). These results provide evidence that the highly-trained athletes do not have the antioxidant buffering capacity to counterbalance free radical over-production generated by acute hypoxic exposure, with or without mild exercise.

Energy expenditure of submaximal running does not increase after cycle-run transition

AIM

This study was performed to determine the relationship between increased fat oxidation and decreased running efficiency following intense cycling exercise.

METHODS

Twenty-two middle-level triathletes were studied during submaximal running before and after submaximal cycling exercise. All subjects completed a 13-min run on a track at a velocity corresponding to 75% of their maximal aerobic speed (MAS) before (T1) and after (T2) submaximal cycling exercise at 75 % of maximal aerobic power (MAP). The energy cost of running (Cr) was quantified using the O(2) uptake (.VO(2)) and energy expenditure (EE) using the respiratory exchange ratio (RER). Gas exchange was measured over 30 s during the 3(rd) min and last 30 s of each run.

RESULTS

The results show that after cardiorespiratory equilibration (12 min 30 s), Cr (calculated in mL(O(2))*kg(-1)*m(-1)) during T2 was higher than during T1 (+ 8.2+/-4.3%; P = 0.03). Similar observations were made for .VO(2) (+ 8.2+/-4.3%; P = 0.03) and pulmonary ventilation (+ 7.0+/-12.3%; P = 0.04). RER decreased between T1 and T2 (- 8.6+/-9.2 %; p = 0.01). EE and Cr expressed in kJ.kg(-1).m(-1) did not vary significantly between T1 and T2.

CONCLUSION

We suggest that the decrease in RER drop may be a result of greater lipid oxidation as metabolic substrate after cycling exercise.

Incidence and impact on clinical outcome of infections with piperacillin/tazobactam resistant Escherichia coli in ICU: a retrospective study

BACKGROUND

Escherichia coli infections are frequent in ICU patients. The increased resistance to fluoroquinolones and amoxicillin/clavulanate of this pathogen mandates the prescription of broad-spectrum antibiotics such as piperacillin/tazobactam (PIP-TAZ) or third generation cephalosporins (3GC).

METHODS

To assess incidence and impact on clinical outcome of infections with PIP-TAZ resistant E. coli in ICU patients, we conducted a retrospective cohort study with infections due to PIP-TAZ resistant (PIP-TAZ R) or to PIP-TAZ susceptible strains (PIP-TAZ S) between 1 January 2002 and 30 June 2004.

RESULTS

Of 83 strains, 13 were PIP-TAZ R: 2 strains produced an extended-spectrum beta-lactamase (2%), 11 produced a high level penicillinase (13%). Prior amoxicillin or amoxicillin/clavulanate prescription was reported in 7 cases (54%) of infections with PIP-TAZ R isolates and in 15 cases (21%) of infections with PIP-TAZ S isolates (p = 0.03). Time of onset of the infection from hospital admission was longer in case of infections with PIP-TAZ R than with PIP-TAZ S isolates (22 +/- 32 vs 10 +/- 21 days, p = 0.01). The overall ICU mortality rate was 38%. Mortality and length of stay in ICU were similar in case of infections with PIP-TAZ R isolates and with PIP-TAZ S isolates.

CONCLUSION

Infections with PIP-TAZ R E. coli are frequent in ICU patients. No prognostic impact of this pattern of resistance was found. Prescription of PIP-TAZ for empirical treatment of E. coli infections in ICU however exposes to inappropriate therapy.

Effects of the 'live high-train low' method on prooxidant/antioxidant balance on elite athletes

BACKGROUND/OBJECTIVES

We previously demonstrated that acute exposure to hypoxia (3 h at 3000 m) increased oxidative stress markers. Thus, by using the 'living high-training low' (LHTL) method, we further hypothesized that intermittent hypoxia associated with endurance training alters the prooxidant/antioxidant balance.

SUBJECTS/METHODS

Twelve elite athletes from the Athletic French Federation were subjected to 18-day endurance training. They were divided into two groups: one group (control group) trained at 1200 m and lived in hypoxia (2500-3000 m simulated altitude) and the second group trained and lived at 1200 m. The subjects performed an acute hypoxic test (10 min at 4800 m) before and immediately after the training. Plasma levels of advanced oxidation protein products (AOPP), malondialdehydes (MDA), ferric-reducing antioxidant power (FRAP), lipid-soluble antioxidants normalized for triacylglycerols, and cholesterol and retinol were measured before and after the 4800 m tests.

RESULTS

After the training, MDA and AOPP concentrations were decreased in response to the 4800 m test only for the control group. Eighteen days of LHTL induced a significant decrease of all antioxidant markers (FRAP, P=0.01; alpha-tocopherol, P=0.04; beta-carotene, P=0.01 and lycopene, P=0.02) for the runners. This imbalance between antioxidant and prooxidant might result from insufficient intakes in vitamins A and E.

CONCLUSIONS

The LHTL model characterized by the association of aerobic exercises and intermittent resting hypoxia exposures decreased the antioxidant status whereas the normoxic endurance training induced preconditioning mechanisms in response to the 4800 m test.

Effects of exercise and training in hypoxia on antioxidant/pro-oxidant balance

OBJECTIVE

The aim was to investigate the effects of acute exercise under hypoxic condition and the repetition of such exercise in a 'living low-training high' training on the antioxidant/prooxidant balance.

DESIGN

Randomized, repeated measures design.

SETTING

Faculté de Médecine, Clermont-Ferrand, France.

SUBJECTS

Fourteen runners were randomly divided into two groups. A 6-week endurance training protocol integrated two running sessions per week at the second ventilatory threshold into the usual training.

INTERVENTION

A 6-week endurance training protocol integrated two running sessions per week at the second ventilatory threshold into the usual training. The first hypoxic group (HG, n=8) carried out these sessions under hypoxia (3000 m simulated altitude) and the second normoxic group (NG, n=6) in normoxia. In control period, the runners were submitted to two incremental cycling tests performed in normoxia and under hypoxia (simulated altitude of 3000 m). Plasma levels of advanced oxidation protein products (AOPP), malondialdehydes (MDA) and lipid oxidizability, ferric-reducing antioxidant power (FRAP), lipid-soluble antioxidants (alpha-tocopherol and beta-carotene) normalized for triacyglycerols and cholesterol were measured before and after the two incremental tests and at rest before and after training.

RESULTS

No significant changes of MDA and AOPP level were observed after normoxic exercise, whereas hypoxic exercise induced a 56% rise of MDA and a 44% rise of AOPP. Plasma level of MDA and arterial oxygen hemoglobin desaturations after the acute both exercises were highly correlated (r=0.73). alpha-Tocopherol normalized for cholesterol and triacyglycerols increased only after hypoxic exercise (10-12%, P<0.01). After training, FRAP resting values (-21%, P<0.05) and alpha-tocopherol/triacyglycerols ratio (-24%, P<0.05) were diminished for HG, whereas NG values remained unchanged.

CONCLUSIONS

Intense exercise and hypoxia exposure may have a cumulative effect on oxidative stress. As a consequence, the repetition of such exercise characterizing the 'living low-training high' model has weakened the antioxidant capacities of the athletes.

SPONSORSHIP

International Olympic Committee and the Direction Régionale de la Jeunesse et des Sports de la Région Auvergne.

Effect of hypervolemia on heart rate during 4 days of prolonged exercises

The aim was to evaluate the cardiodynamic adjustment during 4 days of prolonged exercises and to check if the plasma volume (PV) expansion which is observed generally during such events plays a role in this adaptation. Thirteen subjects exercised 5 hours per day on a cycle ergometer alternately with a treadmill for 4 days (D1 to D4) (6 x 50 min sessions per day). The individual cycle ergometer load and the treadmill speed were unchanged during each exercise session and throughout all the sessions, and corresponded to a moderate exercise intensity: 58 - 63 % of peak oxygen uptake (VO (2)peak). Heart rate (HR) was recorded every 15 s during each exercise session and VO (2) was measured from the expired air at the beginning and the end of each exercise session. Relative PV changes were measured from haematocrit and haemoglobin changes in the morning before the exercise bouts. No significant changes of VO (2) were observed between the first and the last exercise session i. e. for cycling: 2.1 +/- 0.2 l/min and for running: 2.4 +/- 0.3 l/min. Between the first and the last day, HR decreased from 143 to 129 bpm for cycle (p < 0.0001) and from 147 to 137 bpm (p = 0.01) for treadmill. As compared to D1, PV increased gradually from D2 (+ 1.8 % +/- 4.7 %) to D4 (+ 8.5 % +/- 4.7 %). The individual PV increases were significantly correlated with cycling HR decreases from D1 to D4 (r (2) = 0.40, p = 0.02). In conclusion, the 4 days' prolonged exercise induced a HR decrease during submaximal exercise without VO (2) drift. Here we suggested that this HR decline could be in part linked to the transient PV expansion.