Matthieu Eveillard

Evaluation of a strategy of screening multiple anatomical sites for methicillin-resistant Staphylococcus aureus at admission to a teaching hospital.

We compared the sensitivity of screening with nasal culture alone with that of a multiple-site screening method for the identification of carriers of methicillin-resistant Staphylococcus aureus at hospital admission. If nasal cultures alone had been used during the 1-year study, 27.0% of carriers of methicillin-resistant S. aureus would have been missed, which corresponds to 560 theoretical isolation days. If rectal screening had not been used, 431 theoretical isolation days would have been missed, and, if axillary screening had not been used, 99 theoretical isolation days would have been missed.

Seasonal and regional dynamics of M. ulcerans transmission in environmental context: deciphering the role of water bugs as hosts and vectors.

Background Buruli ulcer, the third mycobacterial disease after tuberculosis and leprosy, is caused by the environmental mycobacterium M. ulcerans. Various modes of transmission have been suspected for this disease, with no general consensus acceptance for any of them up to now. Since laboratory models demonstrated the ability of water bugs to transmit M. ulcerans, a particular attention is focused on the transmission of the bacilli by water bugs as hosts and vectors. However, it is only through detailed knowledge of the biodiversity and ecology of water bugs that the importance of this mode of transmission can be fully assessed. It is the objective of the work here to decipher the role of water bugs in M. ulcerans ecology and transmission, based on large-scale field studies. Methodology/Principal Findings The distribution of M. ulcerans-hosting water bugs was monitored on previously unprecedented time and space scales: a total of 7,407 water bugs, belonging to large number of different families, were collected over one year, in Buruli ulcer endemic and non endemic areas in central Cameroon. This study demonstrated the presence of M. ulcerans in insect saliva. In addition, the field results provided a full picture of the ecology of transmission in terms of biodiversity and detailed specification of seasonal and regional dynamics, with large temporal heterogeneity in the insect tissue colonization rate and detection of M. ulcerans only in water bug tissues collected in Buruli ulcer endemic areas. Conclusion/Significance The large-scale detection of bacilli in saliva of biting water bugs gives enhanced weight to their role in M. ulcerans transmission. On practical grounds, beyond the ecological interest, the results concerning seasonal and regional dynamics can provide an efficient tool in the hands of sanitary authorities to monitor environmental risks associated with Buruli ulcer.

Reservoirs of Acinetobacter baumannii outside the hospital and potential involvement in emerging human community-acquired infections.

The objective of the present report was to review briefly the potentially community-acquired Acinetobacter baumannii infections, to update information on the reservoirs of A. baumannii outside the hospital, and to consider their potential interactions with human infections. Most reports on potentially community-acquired A. baumannii have been published during the last 15 years. They concern community-acquired pneumonia, infections in survivors from natural disasters, and infected war wounds in troops from Iraq and Afghanistan. Although the existence of extra-hospital reservoirs of A. baumannii has long been disputed, the recent implementation of molecular methods has allowed the demonstration of the actual presence of this organism in various environmental locations, in human carriage, in pets, slaughter animals, and human lice. Although the origin of the A. baumannii infections in soldiers injured in Southwestern Asia is difficult to determine, there are some arguments to support the involvement of extra-hospital reservoirs in the occurrence of community-acquired infections. Overall, the emergence of community-acquired A. baumannii infections could be associated with interactions between animals, environment, and humans that are considered to be potentially involved in the emergence or re-emergence of some infectious diseases.

The virulence variability of different Acinetobacter baumannii strains in experimental pneumonia.

OBJECTIVES Our objective was to compare the virulence of 5 strains of Acinetobacter baumannii by using a mouse model of pneumonia. METHODS Six-week old female C3H/HeN mice were used. The pneumonia was inducted by intra-tracheal inoculation of 5.10(6) bacteria. Spontaneous outcome was evaluated by mortality, mice weight variations, and a clinical score. Bacterial counts in lungs, spleen and blood, and inflammatory response in lungs (dosages of tumor necrosis factor-alpha and macrophage inflammatory protein-2) were also measured. Lastly, a histological examination of lungs was performed for 3 strains, giving a histological score. RESULTS Global mortality varied from 13% to 79% (P<10(-4)). Bacterial counts in lungs within the 4 days following inoculation varied significantly according to different strains. The evolution curves of bacterial counts were also different. There was a significant correlation between the clinical score and mortality (P<0.05) but not between bacterial counts in lungs and mortality. The increase of pro-inflammatory mediator production in lungs and the histological score also varied according to strains. CONCLUSIONS These results demonstrate the variability of the virulence between strains, and suggest that bacterial proliferation is not the only virulence factor responsible for the pathogenesis in A. baumannii pneumonia.

Coexistence of SHV-4- and TEM-24-Producing Enterobacter aerogenes Strains before a Large Outbreak of TEM-24-Producing Strains in a French Hospital

ABSTRACT In 1996, a monitoring program was initiated at the teaching hospital of Amiens, France, and carried out for 3 years. All extended-spectrum β-lactamase (ESBL)-producing Enterobacter aerogenes isolates recovered from clinical specimens were collected for investigation of their epidemiological relatedness by pulsed-field gel electrophoresis and enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) and determination of the type of ESBL harbored by isoelectric focusing and DNA sequencing. Molecular typing revealed the endemic coexistence, during the first 2 years, of two clones expressing, respectively, SHV-4 and TEM-24 ESBLs, while an outbreak of the TEM-24-producing strain raged in the hospital during the third year, causing the infection or colonization of 165 patients. Furthermore, this strain was identified as the prevalent clone responsible for outbreaks in many French hospitals since 1996. This study shows that TEM-24-producing E. aerogenes is an epidemic clone that is well established in the hospitals ecology and able to spread throughout wards. The management of the outbreak at the teaching hospital of Amiens, which included the reinforcement of infection control measures, failed to obtain complete eradication of the clone, which has become an endemic pathogen.

Methicillin-resistant Staphylococcus aureus carriage in a long-term care facility: hypothesis about selection and transmission

BACKGROUND many studies have identified long-term care facilities (LTCFs) as reservoirs of patients carrying methicillin-resistant Staphylococcus aureus (MRSA). However, few data about the mechanisms of MRSA diffusion in these settings are available. OBJECTIVES the purpose of our study was to suggest hypothesis on the possible ways of MRSA transmission to residents in or outside a LTCF. METHODS data concerning patients on the day of the survey and within the preceding year were collected. Multivariate analysis was performed by logistic regression to identify characteristics associated with MRSA carriage. MRSA strains were analysed by pulsed-field gel electrophoresis (PFGE) and the relatedness between DNA patterns was studied with Gel Compar software. RESULTS the prevalence of MRSA carriage was 37.6%. Treatment with fluoroquinolones or third-generation cephalosporins [odds ratio (OR) = 12.07; 95% confidence interval (CI) = 5.90-24.7], treatment with other antimicrobial agents (OR = 4.40; 95% CI = 2.43-7.97), at least one medical imaging session (OR = 5.08; 95% CI = 2.66-9.69) within the 12 preceding months, and the presence of a subcutaneous catheter on the day of the survey (OR = 3.09; 95% CI = 1.87-5.10) were independently associated with MRSA carriage. Twenty-eight of the 38 strains tested were clustered in two major groups. In each of these groups, strains had at least a 90% relatedness. These strains were isolated in patients hospitalised in different areas of the LTCF. CONCLUSION we identified that both molecular and epidemiological arguments support the hypothesis of the possibility of MRSA cross-transmission inside the LTCF. Further studies are needed to confirm and explain the association identified between MRSA carriage and medical imaging.

First report of blaNDM-1-producing Acinetobacter baumannii isolated in Lebanon from civilians wounded during the Syrian war

OBJECTIVES The emergence of carbapenem-resistant Acinetobacter baumannii has been observed worldwide. We describe the first detection of A. baumannii carrying the blaNDM-1 gene in Lebanon, isolated from Syrian patients wounded during the civil war. METHODS Four carbapenem-resistant A. baumannii strains isolated in 2012 in the Tripoli Government Hospital, Lebanon, from civilians wounded during the Syrian war, were analysed. Susceptibility was determined by disk diffusion testing, and resistance to carbapenems was confirmed by Etest. The presence of blaOXA-23-like, blaOXA-24-like, blaOXA-58-like, blaOXA-143-like, and blaNDM was investigated by PCR. Clonal relationships were studied by pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and blaOXA-51 sequence-based typing. RESULTS All isolates harboured the blaNDM-1 gene and were negative for other tested carbapenemases. They all belonged to the sequence type 85 and formed a single cluster by PFGE. Finally, blaOXA-51-like gene sequencing revealed the presence of the blaOXA-94 variant in all four isolates. CONCLUSION These findings show that Syria constitutes a reservoir for NDM-1-producing bacteria. These results also highlight the need for effective measures to stop the threatening spread of such strains.

Measurement and interpretation of hand hygiene compliance rates: importance of monitoring entire care episodes.

Our objective was to assess the importance of monitoring hand hygiene compliance (HHC) during series of successive contacts with patients or surroundings for measurement and interpretation of the compliance rates. A direct observational study of HHC was performed in four intensive care units (ICUs) and four healthcare settings with non-intensive care wards (NICWs). Hand hygiene (HH) opportunities were differentiated into two categories: extra-series opportunities (ESOs) (before or after a single contact, and before the first contact or after the last contact of a series of successive contacts) or as intra-series opportunities (ISOs) (from the opportunity following the first contact to the opportunity preceding the last in the same series). In all, 903 opportunities of HH were performed in ICUs and 760 in NICWs. The proportion of ISOs was 46.0% in ICUs and 22.9% in NICWs. The overall HHC was significantly higher in NICWs than in ICUs (61.2% vs 47.5%, P<0.00001). The HHC was significantly higher for ESOs than for ISOs (67.7% vs 28.5%, P<0.00001). The HHC for ISOs was significantly higher in ICUs (32.2% vs 19.0%, P<0.005). If the distribution of categories of HH opportunities observed in NICWs had been the same as in ICUs, the overall HHC would have been similar in NICWs (46.4%) and in ICUs (47.5%). Monitoring HHC during entire care episodes in series of successive contacts is necessary to avoid a strong overestimation of the overall compliance rates. Concurrently, comparison of compliance data should take into account the proportion of ISOs included in the evaluation study.

Extrahuman Epidemiology of Acinetobacter baumannii in Lebanon

ABSTRACT The presence of Acinetobacter baumannii outside hospitals is still a controversial issue. The objective of our study was to explore the extrahospital epidemiology of A. baumannii in Lebanon. From February 2012 to October 2013, a total of 73 water samples, 51 soil samples, 37 raw cow milk samples, 50 cow meat samples, 7 raw cheese samples, and 379 animal samples were analyzed by cultural methods for the presence of A. baumannii. Species identification was performed by rpoB gene sequencing. Antibiotic susceptibility was investigated, and the A. baumannii population was studied by two genotyping approaches: multilocus sequence typing (MLST) and bla OXA-51 sequence-based typing (SBT). A. baumannii was detected in 6.9% of water samples, 2.7% of milk samples, 8.0% of meat samples, 14.3% of cheese samples, and 7.7% of animal samples. All isolates showed a susceptible phenotype against most of the antibiotics tested and lacked carbapenemase-encoding genes, except one that harbored a bla OXA-143 gene. MLST analysis revealed the presence of 36 sequence types (STs), among which 24 were novel STs reported for the first time in this study. bla OXA-51 SBT showed the presence of 34 variants, among which 21 were novel and all were isolated from animal origins. Finally, 30 isolates had new partial rpoB sequences and were considered putative new Acinetobacter species. In conclusion, animals can be a potential reservoir for A. baumannii and the dissemination of new emerging carbapenemases. The roles of the novel animal clones identified in community-acquired infections should be investigated.

Differences in Acinetobacter baumannii Strains and Host Innate Immune Response Determine Morbidity and Mortality in Experimental Pneumonia

Despite many reports documenting its epidemicity, little is known on the interaction of Acinetobacter baumannii with its host. To deepen our insight into this relationship, we studied persistence of and host response to different A. baumannii strains including representatives of the European (EU) clones I–III in a mouse pneumonia model. Neutropenic mice were inoculated intratracheally with five A. baumannii strains and an A. junii strain and at several days morbidity, mortality, bacterial counts, airway inflammation, and chemo- and cytokine production in lungs and blood were determined. A. baumannii RUH875 and RUH134 (EU clone I and II, respectively) and sporadic strain LUH8326 resulted in high morbidity/mortality, whereas A. baumannii LUH5875 (EU clone III, which is less widespread than clone I and II) caused less symptoms. A. baumannii type strain RUH3023T and A. junii LUH5851 did not cause disease. All strains, except A. baumannii RUH3023T and A. junii LUH5851, survived and multiplied in the lungs for several days. Morbidity and mortality were associated with the severity of lung pathology and a specific immune response characterized by low levels of anti-inflammatory (IL-10) and specific pro-inflammatory (IL-12p40 and IL-23) cytokines at the first day of infection. Altogether, a striking difference in behaviour among the A. baumannii strains was observed with the clone I and II strains being most virulent, whereas the A. baumannii type strain, which is frequently used in virulence studies appeared harmless.