[Emerging Acinetobacter baumannii infections and factors favouring their occurrence]. / Infections émergentes à Acinetobacter baumannii et circonstances favorisant leur survenue.

During the last decade, Acinetobacter baumannii (AB) has been increasingly responsible for infections occurring in three particular contexts (in terms of patients and environment). Community AB pneumonia is severe infections, mainly described around the Indian Ocean, and which mainly concern patients with major co-morbidities. AB is also responsible for infections occurring among soldiers wounded in action during operations conducted in Iraq or Afghanistan. Lastly, this bacterium is responsible for infections occurring among casualties from natural disasters like earthquakes and tsunamis. Those infections are often due to multidrug-resistant strains, which can be implicated in nosocomial outbreaks when patients are hospitalized in a local casualty department or during their repatriation thereafter. The source of the contaminations which lead to AB infections following injuries (warfare or natural disasters) is still poorly known. Three hypotheses are usually considered: a contamination of wounds with environmental bacteria, a wound contamination from a previous cutaneous or oropharyngeal endogenous reservoir, or hospital acquisition. The implication of telluric or agricultural primary reservoirs in human AB infections is a common hypothesis which remains to be demonstrated by further specifically designed studies.

[In vitro activity of tigecycline on 760 bacterial strains isolated in the hospital university of Angers--2006-2009 TEST study]. / Activité in vitro de la tigécycline vis-à-vis de 760 souches bactériennes isolées au CHU d'Angers--le programme TEST 2006-2009.

Tigecycline (TGC), an antibiotic belonging to glycylcyclines, is active against Gram-positive bacteria, including multi-resistant bacteria, and most of the Gram-negative bacteria, including extended spectrum ß-lactamase-producers (ESBL) and Acinetobacter sp. TGC is not active on Pseudomonas aeruginosa. The microbiological laboratory from the university hospital of Angers participates in the Tigecycline Evaluation and Surveillance Trial (TEST) since 2006. The objective of this study is to evaluate the effectiveness of TGC and of various comparators against nosocomial and community-acquired pathogens. We also evaluated the effectiveness of TGC on a panel of strains isolated between 2006 and 2009 in the university hospital of Angers. Minimum inhibitory concentrations (MIC) were determined using the microdilution method. A total of 760 clinical strains were tested. TGC had a very good activity against Gram-positive bacteria, with 100 % of susceptibility for all the strains tested, irrespective of their resistance profile. Concerning Gram-negative bacteria, TGC was active against 93 % of Enterobacteriaceae, with a MIC 90 not exceeding 2mg/L. Whole of the 20 strains ESBL-producers tested were susceptible to TGC. Acinetobacter sp. were also inhibited at low concentrations of TGC, with a MIC 90 of 1mg/L. These results suggest that TGC can be a useful therapeutic alternative, especially for infections involving multiresistant bacteria.

[Surgical-site infections following varicose vein surgery according to a continuous series of 408 interventions in a teaching hospital]. / Infections du site opératoire sur ablation de varices d'après une série continue de 408 interventions réalisées dans un centre hospitalier universitaire.

OBJECTIVE: To determine the incidence of surgical-site infections (SSI) following varicose vein surgery in the vascular surgery ward of a French teaching hospital. PATIENTS AND METHODS: A prospective surveillance of SSI was conducted during one year, with a 30-day postoperative follow-up. SSI cases were identified by using the definitions of the Centers for Disease Control (CDC, USA). Data acquisition and analysis were performed with the Epi-Info 6.04 software (CDC). RESULTS: Three quarters of the 408 included interventions were characterized by a NNIS score equal to 0. All patients underwent a hair removing practice before intervention. Hair removing methods were very heterogeneous and often not in accordance with national recommendations (e.g. mechanic shaving for 44.6% of patients). The incidence of SSI was 1.2% (95% confidence interval=[0.2-2.2]). All infections were identified after hospital discharge. Four infected patients out of five presented obesity or excess weight, and two patients had diabetes mellitus. The mean age of infected patients was significantly higher than non-infected ones (70.4 years versus 52.0; p<0.01). All SSI had consequences like rehospitalization, reintervention, or antimicrobial therapy. CONCLUSION: According to our results, SSI following varicose vein surgery are scarce and mainly concerned high-risk patients. However, in an aim of prevention, it seems necessary to homogenize hair removing methods in this ward.

[Antibacterial activity against 224 clinical bacterial strains of JCA 250 and JCA 251 compounds containing essential oils provided from Aroma Technologies research]. / Étude de la sensibilité de 224 bactéries isolées d'infections hospitalières vis-à-vis des composés JCA 250 et JCA 251 à base d'huiles essentielles issus de la recherche Aroma Technologies.

OBJECTIVE: It was to determine the antibacterial spectrum of JCA 250 and JCA 251, two naturally occurring compounds from Aroma Technologies research, on a bacterial population isolated from clinical infections. METHOD: Two hundred and twenty-four bacterial strains were tested. The minimum inhibitory concentrations (MIC) of JCA 250 and JCA 251 were determined by agar dilution method. Tests were performed in triplicate. RESULTS: The mean MIC was 0.20% for JCA 250 and 0.15% for JCA 251. JCA 251 regularly exhibited greater activity. All Enterobacteriaceae were inhibited at concentrations less or equal to 0.15% for JCA 250 or JCA 251. For strict aerobes, the MIC values were more spread out. Two Pseudomonas aeruginosa strains differed from the population with JCA 251 MIC of 0.25 and 0.40%. Concerning Gram-positive cocci, all the strains were inhibited with less or equal to 0.25% of compound. The most resistant population were the Enterococci and the Lactobacilli, with MIC more or equal to 0.2% for JCA 250 or JCA 251. Anaerobes showed MIC closely grouped for a heterogeneous bacterial group. One Propionibacterium sp. strain came apart from the group and was inhibited with a MIC of 0.5%. CONCLUSION: The overall results showed an interesting antibacterial activity on bacteria isolated from clinical samples. Most of the bacterial strains were inhibited at a concentration of 0.2%. The highest mean values were obtained for commensal bacteria from the flora, which is of particular interest in this study.

[Pays de la Loire Pneumococcus Observatory: antimicrobial resistance of Streptococcus pneumoniae in 2007]. / Observatoire régional du pneumocoque en région Pays de la Loire: résistance de Streptococcus pneumoniae aux antibiotiques en 2007.

OBJECTIVES: Between 1st January and 31st December 2007, 331 Streptococcus pneumoniae strains were collected from 20 participating laboratories in the Pneumococcus Network Pays de la Loire county to assess their susceptibility to antibiotics and to evaluate serogroups of strains. METHOD: The coordinating centre performed MICs of penicillin G, amoxicillin and cefotaxime by the reference agar dilution method. Results were interpreted according to CA-SFM breakpoints. Sensitivity to other antibiotics were studied and serotyping of each strain performed. RESULTS: Three hundred and thirty one strains were isolated in 2007. They were collected from 30 cerebrospinal fluids, 239 blood samples, 53 middle ear fluids and nine pleural fluids. The percentage of pneumococci with decreased susceptibility to penicillin G (PDSP) was 39% and was higher in children (51%) than in adults (35%). The PDSP were often multidrug resistants especially with a high percentage of resistance to erythromycin (87.6% versus 8.4% for pneumococci sensitive to penicillin G). Finally, the most prevalent serogroup was the serogroup 19 (29.6% of isolates). CONCLUSION: A decrease of PDSP was observed since 2001 and high-level resistant strains to beta-lactams remain low. The rate of PDSP in Pays de la Loire is in the national average.

Management of an Acinetobacter baumannii outbreak in an intensive care unit.

INTRODUCTION: Acinetobacter baumannii is a ubiquitous pathogen resistant to desiccation and responsible for healthcare-associated infections (HAI), especially in intensive care units (ICU) where it is responsible for 5-10% of HAIs. An A. baumannii outbreak occurred in the ICU of the University Hospital of Angers, France. OBJECTIVES: To describe the A. baumannii outbreak and to evaluate the control measures taken. The secondary objective was to evaluate the impact of the electronic alert system on the incidence of multidrug resistance to antibiotics. METHODS: We performed a descriptive study of A. baumannii carriers during the outbreak. Case contacts and carriers were described using the epidemic curve and a case synopsis table. RESULTS: From August 2011 to September 2013, 49 patients presenting with an extended-spectrum beta-lactamase-producing A. baumannii infection were identified: thirty-four were colonized and 15 were infected. No death was due to the outbreak. Measures taken were: geographical and technical isolation of patients, dedicated team implementation, contact precaution implementation including hand hygiene measures, appropriate use of gloves, and reinforcement of bio-cleaning procedures. CONCLUSION: Some patients were re-admitted to hospital while still being carriers; this could explain epidemic peaks. The immersion mission of the hygiene nurse contributed to answering healthcare workers' queries and led to a better cooperation between the ICU and the hygiene team.

Impact of selective screening in the emergency department on meticillin-resistant Staphylococcus aureus control programmes.

Identification of the meticillin-resistant Staphylococcus aureus (MRSA) reservoir by active screening followed by the implementation of contact precautions is one of the major components of MRSA control programmes. The objective of this study was to evaluate the results of a programme of selective screening in an emergency department (ED) and the appropriateness of the contact precautions implemented. This was estimated by distinguishing necessary and unnecessary days of contact precautions. This estimation was performed for all days of contact precautions and, more specifically, for days of preventive contact precautions implemented before the availability of screening results. During a three-year period, screening of MRSA carriers was performed on 0.95% (N=605) of patients visiting the emergency ward. Among the 193 (31.9%) MRSA carriers identified, 159 were hospitalized in the short-length-hospitalization area (SLHA) of the ED and/or in other wards. Among the 140 patients admitted to the SLHA, 44 were hospitalized for at least 48 h, with a mean length of hospitalization of 5.9 days. The cumulative duration of hospitalization of carriers identified by screening was 1897 days. In total, 2370 days of contact precautions (including 924 days of preventive precautions) were implemented for patients screened in the ED. Considering the whole hospital, the appropriateness of this entire programme of contact precautions for patients screened in the ED was 80.0% (52.1% for the SLHA), whereas the specific appropriateness of preventive isolation days was 48.6% (43.6% for the SLHA). This study underscores the risk of MRSA cross-transmission in the SLHA, and the usefulness of implementing a control programme of screening carriers in the ED.

Influence of fluoride, hydrogen peroxide and lactic acid on the corrosion resistance of commercially pure titanium.

Titanium is widely used in dental implantology and orthopaedics due to its excellent corrosion resistance and mechanical properties. However, it has been reported that Ti is sensitive to F(-), H(2)O(2) and lactic acid. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to investigate the corrosion resistance of CP-Ti disks after 9 days immersion in different test solutions, based on artificial saliva containing F(-) (0.5% and 2.5%), H(2)O(2) (0.1% and 10%) and/or lactic acid. Because activated macrophages and bacteria can also release locally some of these oxidative compounds, we investigated the role of these cells when plated onto titanium disks. The surface roughness (R(a)) was highly increased when titanium disks were immersed in artificial saliva containing F(-), H(2)O(2) and lactic acid. After 21 days of cell culture, R(a) was significantly increased on disks incubated with activated-J774.2 cells or Streptococcus mitis. AFM appeared to be more sensitive than SEM in evaluating the corrosion of the titanium. Chemical species, either environmental or those released by macrophages and bacteria, can provoke a marked attack of the titanium surface.

Emergence of NDM-1 and OXA-72 producing Acinetobacter pittii clinical isolates in Lebanon.

Acinetobacter spp. have emerged as global opportunistic pathogen causing a wide range of infections. Emergence of carbapenem resistance in these organisms is a matter of great concern. We report here the first detection of Acinetobacter pittii clinical isolates in Lebanon carrying either the bla NDM-1 or the bla OXA-72 gene.

Demonstration of the interactions between aromatic compound-loaded lipid nanocapsules and Acinetobacter baumannii bacterial membrane.

Acinetobacter baumannii is an important nosocomial pathogen that is resistant to many commonly-used antibiotics. One strategy for treatment is the use of aromatic compounds (carvacrol, cinnamaldehyde) against A. baumannii. The aim of this study was to determine the interactions between bacteria and lipid nanocapsules (LNCs) over time based on the fluorescence of 3,3'-Dioctadecyloxacarbocyanine Perchlorate-LNCs (DiO-LNCs) and the properties of trypan blue to analyse the physicochemical mechanisms occurring at the level of the biological membrane. The results demonstrated the capacity of carvacrol-loaded LNCs to interact with and penetrate the bacterial membrane in comparison with cinnamaldehyde-loaded LNCs and unloaded LNCs. Modifications of carvacrol after substitution of hydroxyl functional groups by fatty acids demonstrated the crucial role of hydroxyl functions in antibacterial activity. Finally, after contact with the efflux pump inhibitor, carbonylcyanide-3-chlorophenyl hydrazine (CCCP), the results indicated the total synergistic antibacterial effect with Car-LNCs, showing that CCCP is associated with the action mechanism of carvacrol, especially at the level of the efflux pump mechanism.

Synergistic interactions between doxycycline and terpenic components of essential oils encapsulated within lipid nanocapsules against gram negative bacteria.

The combination of essential oils (EOs) with antibiotics provides a promising strategy towards combating resistant bacteria. We have selected a mixture of 3 major components extracted from EOs: carvacrol (oregano oil), eugenol (clove oil) and cinnamaldehyde (cinnamon oil). These compounds were successfully encapsulated within lipid nanocapsules (LNCs). The EOs-loaded LNCs were characterised by a noticeably high drug loading of 20% and a very small particle diameter of 114nm. The in vitro interactions between EOs-loaded LNCs and doxycycline were examined via checkerboard titration and time-kill assay against 5 Gram-negative strains: Acinetobacter baumannii SAN, A. baumannii RCH, Klebsiella pneumoniae, Escherichia coli and Pseudomonas aeruginosa. No growth inhibition interactions were found between EOs-loaded LNCs and doxycycline (FIC index between 0.7 and 1.30). However, when bactericidal effects were considered, a synergistic interaction was observed (FBC index equal to 0.5) against all tested strains. A synergistic effect was also observed in time-kill assay (a difference of at least 3 log between the combination and the most active agent alone). Scanning electron microscopy (SEM) was used to visualise the changes in the bacterial membrane. The holes in bacterial envelope and leakage of cellular contents were observed in SE micrographs after exposure to the EOs-LNCs and the doxycycline combination.

First report of Oxa-72-producing Acinetobacter calcoaceticus in Lebanon.

Emergence of carbapenem-resistant Acinetobacter spp. has been increasingly reported worldwide. We report here the first detection of an Acinetobacter calcoaceticus isolate from vegetables in Lebanon carrying the bla Oxa-72 gene. These findings show that the Lebanese environment may constitute a potential reservoir for this antibiotic resistance gene.

Clinical impact and pathogenicity of Acinetobacter.

Members of the genus Acinetobacter have been implicated in a wide spectrum of infectious diseases. Although this organism is associated primarily with nosocomial infections, it has also been involved in cases of community-acquired infection. Before the 1970s, Acinetobacter infections were mostly post-surgical urinary tract infections in patients hospitalised in surgical units. The significant improvement in resuscitation techniques during the last 30 years has changed the types of infection caused by Acinetobacter. Since the 1980s, Acinetobacter has spread rapidly among patients in intensive care units. Today, Acinetobacter accounts for c. 9% of nosocomial infections, with most Acinetobacter infections involving the respiratory tract. Transmission via the hands of hospital staff has become the most important contributory factor in patient colonisation. Acinetobacter baumannii is the species that is involved most frequently in infections of humans, but a natural reservoir for A. baumannii outside the hospital environment has not yet been identified. Community-acquired infection and infections acquired following war or natural disasters (e.g., earthquakes) have been described. Acinetobacter causes mild-to-severe illness, but can be fatal. The severity of Acinetobacter infection depends upon the site of infection and the patient's susceptibility to infection as a result of underlying disease. The circumstances that allow Acinetobacter to assume a pathogenic role are not really well-understood. As this organism is a low-grade pathogen, the pathogenesis of Acinetobacter infections probably involves numerous factors, including virulence determinants, which have yet to be investigated.

Impact of screening for MRSA carriers at hospital admission on risk-adjusted indicators according to the imported MRSA colonization pressure.

We evaluated the impact of the different components of a screening programme of methicillin-resistant Staphylococcus aureus (MRSA) carriers at hospital admission on the value of two risk-adjusted rates: the proportion of imported MRSA and an indicator of the MRSA colonization pressure (ICP), and the incidence of MRSA acquired and detected in our hospital. Indicators were calculated: (1) with no screening programme; (2) with a programme limited to the intensive care unit (ICU); (3) with a programme extended to patients with risk factors for MRSA carriage hospitalized in non-ICU wards. The programme included an automatic alert. Systematic sampling of patients with risk factors hospitalized in non-ICU settings detected nearly 50% of carriers at admission. The proportion of MRSA imported into our hospital varied from 35.4% without any screening programme to 71.8% when all components of our screening programme were considered (P<10(-4)). The ICP varied from 3.1% (31/985) with the complete programme to 10.4% (31/297) without any screening programme (P<10(-6)). Screening patients with risk factors for MRSA carriage hospitalized in non-ICU wards resulted in a 51% increase of the calculated proportion of imported strains and a 58% decrease of the ICP. The two studied indicators were strongly dependent on the screening strategy for MRSA carriers implemented at admission. The screening strategy for patients admitted to non-ICU wards who have risk factors for MRSA carriage seems to be the determinant for the interpretation of certain risk-adjusted indicators of MRSA cross-transmission. Comparisons of these indicators must consider the setting in which the screening programmes are implemented.

Estimation of methicillin-resistant Staphylococcus aureus transmission by considering colonization pressure at the time of hospital admission.

Our objective was to evaluate the accuracy of a methicillin-resistant Staphylococcus aureus (MRSA) rate using the imported MRSA reservoir identified at the time of hospital admission. Two indicators were used: the number of imported MRSA patient-days/total number of patient-days [representing colonization pressure (CP) at the time of admission] and the incidence of hospital-acquired MRSA isolated from clinical samples expressed as density/100 patient-days for carriers identified at the time of admission [representing the incidence taking CP into account (ICP)]. The variations of these indicators were analysed and compared with two more common indicators: percentage of MRSA acquired in our hospital and the incidence of hospital-acquired MRSA isolated from clinical samples expressed as density/1000 patient-days within three four-month periods during 2002. Common indicators varied similarly, with marked decline during the third period; first-period CP was twice that of other periods (P<10(-6)) and the highest (>two-fold) ICP was seen in the summer (second) period (P<0.001) when the personnel/patient ratio was the lowest. Thus, comparison of different indicators within four-month periods underlines important differences between common and novel indicators. Despite several limitations, ICP should be helpful in the interpretation of MRSA surveillance data, particularly for estimating the extent of MRSA transmission.

Practical recommendations for the drug treatment of bacterial infections of the male genital tract including urethritis, epididymitis and prostatitis.

Bacterial infections of the male genital tract in young men (<35 years old) are primarily caused by sexually transmissible bacteria like Chlamydia trachomatis, Neisseria gonorrhoeae but also Mycoplasma or Haemophilus spp. In men aged over 35 years, Enterobacteriaceae are more frequently involved in urethritis, epididymitis and prostatitis. The traditional treatments suggested like tetracyclines or erythromycin are less effective since bacterial resistance is increasingly frequent, particularly in N. gonorrhoeae. Moreover, patient compliance with these drug treatments are frequently not well observed. New therapies including short term therapy with fluoroquinolones or azalides (e.g. azithromycin) are very effective and easy to use and thus eliminate any problem of compliance. However, we have to be vigilant for the emergence of resistant strains to these agents.

Usefulness of quantitative cultures of BAL fluid for diagnosing nosocomial pneumonia in ventilated patients.

STUDY OBJECTIVE: To evaluate the role of quantitative cultures of BAL for diagnosing nosocomial pneumonia in mechanically ventilated patients. DESIGN: Cohort study. SETTING: Medical ICU, Hôpital Bichat, Paris, France, an academic tertiary care center. PATIENTS: A total of 141 episodes of suspected lung infection in 84 consecutive patients mechanically ventilated for 48 h or more. MEASUREMENTS AND RESULTS: Microbiologic findings obtained using BAL were compared with those obtained with protected specimen brush (PSB) samples and their operating characteristics were determined. The level of qualitative agreement between BAL and PSB specimen cultures was high, with 83% of the organisms isolated in PSB specimens being recovered simultaneously from BAL fluid. In addition, the results of quantitative BAL and PSB cultures were significantly correlated (rho = 0.46, p < 0.0001). Fifty-seven cases of pneumonia were diagnosed based on the following criteria: PSB sample yielding > or = 10(3) cfu/mL of at least one microorganism and/or > or = 5% of cells containing intracellular bacteria on direct examination of BAL. The operating characteristics of BAL fluid cultures were determined using different ways to report the results and over a range of values. The discriminative value of 10(4) cfu/mL was found to be an optimal threshold, with a sensitivity of 82% (95% confidence interval [CI], 76 to 88) and a specificity of 84.5% (95% CI, 79 to 90). CONCLUSIONS: These results indicate that BAL fluid cultures can offer a sensitive and specific means to diagnose pneumonia in ventilated patients and may provide relevant information about the causative pathogens.

Nosocomial bacteremia in HIV patients: the role of peripheral venous catheters.

A retrospective case-control study compared 40 human immunodeficiency virus (HV)-infected patients with 43 nosocomial bacteremias (NB) to 77 HIV-infected patients without NB. Presence of a peripheral venous catheter (PVC) was associated with occurrence of NB and was significantly more frequent in NB without an identified source. PVCs probably are an underestimated source of NB in HIV-infected patients.

Microbiological evaluation of central venous catheter administration hubs.

We compared, in three intensive care units, colonization of hubs with hub protection boxes or hubs with needleless closed connectors; 137 central venous catheters and 451 hubs were randomized in two groups with similar characteristics. Catheter and hub colonization were not different between the two groups. Among 30 colonized catheters, the same isolate was found in only two hubs; hub contamination rarely is responsible for catheter colonization in short-term catheters. Further studies are required to evaluate the benefit of protected hubs compared with unprotected hubs.