Hélène Pailhoriès

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.

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.

High prevalence of closely-related Acinetobacter baumannii in pets according to a multicentre study in veterinary clinics, Reunion Island

Our objective was to study the carriage of Acinetobacter baumannii (AB) in pets in Reunion Island (RI), a French territory in Indian Ocean. Overall, 138 pets were sampled (rectum, mouth, wounds if applicable) in 9 veterinary clinics (VC). The prevalence of AB carriage was 6.5% (95%CI; 2.4, 10.6) and 9 carriers were identified from 4 VC. Hospitalization in a VC and antimicrobial treatment administered within the 15 preceding days were significantly associated with AB carriage (P<0.01 and P<0.05, respectively). Despite the VC in which animals have been sampled were located all around RI, most isolates (8/9) were closely-related (>90% similarity by pulsed-field gel electrophoresis). Additional studies are needed to improve the understanding about interactions between the different reservoirs of AB in RI.

First report of carbapenemase-producing Acinetobacter baumannii carriage in pets from the community in France

Acinetobacter baumannii is responsible for nosocomial infections but can also cause community-acquired infections. Communityacquired infections are more prevalent in intertropical areas [1] and have been reported in survivors of natural disasters such as earthquakes or tsunamis as well as in soldiers and civilians duringwarfare. These latter observations support the assumption of an extrahospital reservoir of A. baumannii, but its epidemiology outside the hospital remains unclear. One potential community reservoir of A. baumannii is animals. A. baumannii is known as an agent of nosocomial infection in veterinarymedicine. By contrast, little is known regarding A. baumannii carriage incompanionanimals in thecommunity. Twopreviousstudies showed a high prevalence of A. baumannii carriage in companion animals of La Reunion Island (France) [2,3]. These studies were conducted in a tropical area, known as a potential predisposing factor for A. baumannii infection and carriage [1]. Conversely, few data are available for A. baumannii carriage in companion animals in temperate climates. The objective of this studywas to assessA. baumannii carriage in domesticated animals coming for a consultation in the veterinarian school of Nantes (ONIRIS), in metropolitan France. From April 2015 to June 2015, 150 pets (46 cats and 104 dogs) that consulted in the preventive medicine service were included in the study andwere sampled bymouth and rectal swabbing. A questionnaire about the animalwas also completedby theowner. Cultures were performed and A. baumannii colonies were identified using a VITEK®MS Plus Identification System (bioMérieux, Marcy-l’Étoile, France) and rpoB gene sequencing. Of the 150 animals, 4 carried A. baumannii (2.7%; 95% confidence interval 0.1–5.3%). These animals were dogs living in Nantes city or its surrounding areas (Table 1). Strains isolated from Dogs 1 and 2 were resistant to penicillins and penicillin/β-lactamase inhibitor combinations but remained susceptible to ceftazidime according to the Antibiogram Committee of the French Society for Microbiology (CASFM) recommendations (http://www.sfm-microbiologie.org/UserFiles/files/casfm/CASFMV2 _030915.pdf). They were also resistant to aminoglycosides, trimethoprim/sulfamethoxazole, ciprofloxacin and doxycycline. Both strains were highly resistant to imipenem [minimum inhibitory concentration (MIC) > 32 μg/mL], doripenem (MIC > 32 μg/mL) and meropenem (MIC > 32 μg/mL) as determined by Etest (bioMérieux). These strains were positive for the blaOXA-23 gene and were negative for blaOXA-24, blaOXA-58 and blaNDM by real-time PCR. Conversely, strains isolated from Dogs 3 and 4 were susceptible to the majority of antibiotics tested. Among the four A. baumannii strains, the Institut Pasteur multilocus sequence typing (MLST) scheme showed that the two carbapenem-resistant strains belonged to ST25; another strain belonged to ST250 and the last strain to a new sequence type, ST753. Pulsed-field gel electrophoresis (PFGE) analysis using the restriction enzyme ApaI revealed that the two ST25 A. baumannii strains had 100% homology, conclusive of a unique clone. The rate of A. baumannii carriage (2.7%) was lower than in La Reunion (6.5% [2] and 8.5% [3]). This difference may be partially explained by climate influence. Indeed, community-acquired A. baumannii infections are mainly reported in tropical climates [1]. La Reunion Island is located in a tropical climate, whilst the current study was conducted in metropolitan France, a temperate climate. Chen et al studied the impact of climatic variations on communityacquired A. baumannii pneumonia in humans and demonstrated that the prevalence of A. baumannii infections was higher during warm and humid months of the year [1]. We can suggest here that climate could also have an impact on A. baumannii carriage in companion animals. Further studies are necessary to assess this conclusion. Here we describe the first case of carbapenem-resistant A. baumannii carriage in non-hospitalised companion animals. The blaOXA-23 gene reported here has also been described in A. baumannii in animals, such as in hospitalised horses [4]. An OXA-23-producing A. baumannii strain has also been described in a cat hospitalised for a urinary tract infection [5]. This cat was infected and received antibiotherapy the month preceding the swabbing. Conversely, the pets included in the current study had no history of previous infections or antibiotic treatments. This observation raises questions about the extent of the circulation of carbapenemase-producing A. baumannii in companion animals in metropolitan France. The two carbapenem-resistant strains were similar by PFGE analysis. We do not exclude a potential cross-contamination of the two dogs. The two dogs, sampled the same day, could have been sampled in the same consultation box, hypothetically contaminated by this A. baumannii clone. No samplingwas performed in the boxes to verify this hypothesis. However, considering the practices of the professionals involved in the pet outpatient clinic, the risk of crosstransmission seems particularly weak. In conclusion, to our knowledge we describe here the first report of OXA-23-producing A. baumannii carriage in domesticated animals in metropolitan France. Further investigations must be conducted to assess A. baumannii carriage in pets in metropolitan France and to identify transmission mechanisms within the animals and also with their owners and their environment.

Diversity of Acinetobacter baumannii strains isolated in humans, companion animals, and the environment in Reunion Island: an exploratory study

OBJECTIVES Acinetobacter baumannii can be responsible for community-acquired infections in tropical climates like that of Reunion Island. The epidemiology of these community-acquired A. baumannii infections is not well understood. The aim of this study was to characterize A. baumannii strains isolated from patients at the time of admission to the university hospital of Saint-Denis, from environmental samples, and from pets. METHODS In this exploratory study, samples were collected by swabbing the rectum and mouth. A. baumannii isolates from positive samples were identified by VITEK 2 system, blaOXA-51-like gene PCR, and partial sequencing of the rpoB gene. Antimicrobial susceptibility testing was then performed. Strains were further analysed by multilocus sequence typing and pulsed-field gel electrophoresis. RESULTS A high prevalence of A. baumannii carriage was found in pets (8.5%). Only one A. baumannii isolate was resistant to carbapenems (isolated from a patient). A wide variety of A. baumannii, assigned to different sequence types, were isolated from pets, humans, and the environment. CONCLUSIONS This study shows that A. baumannii strains are present outside the hospital setting in Reunion Island and show great diversity. Further studies are needed to explore these extra-hospital reservoirs of A. baumannii in Reunion Island in greater detail and to determine their possible means of dissemination.

Fortuitous diagnosis of NDM-1-producing Acinetobacter pittii carriage in a patient from France with no recent history of travel.

L’UNAM Université, Université d’Angers, ATOMycA, Inserm Equipe Avenir, CRCNA, Inserm U892, 6299 CNRS – IRIS, CHU, 4 rue Larrey, 49933 Angers cedex, France; Laboratoire de Bactériologie, Institut de Biologie en Santé—PBH, CHU, 4 rue Larrey, 49933 Angers cedex, France; Unité de recherche sur les maladies infectieuses et tropicales émergentes (URMITE), UM 63, CNRS 7278, IRD 198, INSERM 1095, IHU Méditerranée Infection, Faculté de Médecine et de Pharmacie, Aix-Marseille Université, Marseille, France; Service de Maladies Infectieuses et Tropicales—CHU, 4 rue Larrey, 49933 Angers cedex, France

Using Vitek MALDI-TOF mass spectrometry to identify species belonging to the Acinetobacter calcoaceticus–Acinetobacter baumannii complex: a relevant alternative to molecular biology?

Acinetobacter baumannii belongs to the Acinetobacter calcoaceticus-baumannii complex (Acb) containing 2 other pathogenic species: Acinetobacter pittii and Acinetobacter nosocomialis. Identification of these bacteria remains problematic despite the use of matrix-assisted laser ionization time-of-flight mass spectrometry (MALDI-TOF MS). Here, we enriched the SARAMIS™ database of the Vitek MS® plus mass spectrometer to improve the identification of species of the Acb complex. For each species, we incremented reference spectra. Then, a SuperSpectrum was created based on the selection of 40 specific masses. In a second step, we validated reference spectra and SuperSpectra with 100 isolates identified by rpoB gene sequencing. All the isolates were correctly identified by MALDI-TOF MS with the database we created as compared to the identifications obtained by rpoB sequencing. Our database enabled rapid and reliable identification of the pathogen species belonging to the Acb complex. Identification by MALDI-TOF MS with our database is a good alternative to molecular biology.

A case report of Mycoplasma hominis brain abscess identified by MALDI-TOF mass spectrometry.

We report the case of a 43-year-old man with a Mycoplasma hominis brain abscess occurring after a cranial trauma, which was identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The presence of colonies on classic blood agar plates and the use of MALDI-TOF MS, a valuable diagnostic tool that identified M. hominis due to its presence in the VITEK MS database, allowed the rapid diagnosis of this infection.

Discordance in the minimal inhibitory concentrations of ertapenem for Enterobacter cloacae: Vitek 2 system versus Etest and agar dilution methods

Our objective was to compare the ertapenem minimal inhibitory concentrations (MICs) for Enterobacter cloacae isolates categorized intermediate or resistant to ertapenem when measured with the Vitek 2 system, with the MICs for these isolates when measured by two methods performed in agar medium: the Etest and agar plate dilution method (APDM). Overall, 50 E. cloacae isolates were included in the study. The mean MIC of ertapenem was 2.92±1.77μg/ml according to the Vitek 2 system, 0.94±0.84μg/ml according to the Etest strips, and 0.93±0.62μg/ml according to the APDM. Furthermore, the MICs determined by the Vitek 2 system were higher than the MICs determined by the two other methods for 96% of strains. Lastly, according to the Etest strips and APDM, 42% of E. cloacae were susceptible to ertapenem. No carbapenemase was identified by the screening method used. Using the Vitek 2 system to determine ertapenem MICs for E. cloacae can have potential consequences in terms of additional carbapenemase-detecting tests and antimicrobial therapy. It would be interesting to determine if the Vitek 2 system is more effective for the detection of carbapenemase producers with low-level carbapenem resistance than the two methods performed in agar medium.

First case of OXA-24-producing Acinetobacter baumannii in cattle from Reunion Island, France

Asymptomatic carriage of Acinetobacter baumannii has been identified in animals in Reunion Island, France [1,2]. The first study found 6.5% of pets sampled in veterinary clinics colonised with closely related A. baumannii assigned to sequence type 25 (ST25) [1], and another study identified a similar prevalence associated with high strain diversity [2]. These studies demonstrated the presence of A. baumannii outside the hospital setting on this island. Therefore, we wanted to explore other potential extrahuman reservoirs of A. baumannii in this area. The objective here was to report the results of a screening campaign performed on a sample of cattle to identify A. baumannii carriage on a farm on Reunion Island. On one day, the cattle heads inspected by a veterinarian on a single farm during routine examination were sampled by mouth swabbing. Swabs were inoculated in UTI agar medium (Oxoid Ltd., Basingstoke, UK), CHROMagarTM Acinetobacter agar medium (CHROMagar, Paris, France) and chromIDTM BLSE agar medium (bioMérieux, Marcy-l’Étoile, France). The agar media were incubated for 48 h at 37 °C. Suspected A. baumannii colonies on culture were identified using a VITEK®2 system (bioMérieux) and by partial sequencing of the rpoB gene as reported previously [2]. Antimicrobial susceptibility was determined by the disk diffusion method according to the recommendations of the French Society for Microbiology (http://www.sfm-microbiologie.org). Multilocus sequence typing (MLST) and determination of the presence of carbapenemaseencoding genes (blaOXA-23, blaOXA-24, blaOXA-58 and blaNDM-1) were performed as previously described [2]. From the 50 cattle heads of the farm, 6 were sampled. A. baumannii carriage was identified in five animals. Surprisingly, one isolate was resistant to carbapenems due to presence of the blaOXA-24 gene. All isolates remained susceptible to aminoglycosides, colistin, rifampicin and ciprofloxacin. The A. baumannii isolates were assigned to different STs: four to STs never identified previously (ST479, ST480, ST482 and ST587) and one to ST278. This is the first report of carbapenem-resistant A. baumannii isolated in cattle in France. This isolate belongs to a new ST (ST587). Carbapenem-resistant Acinetobacter spp. and A. baumannii have already been identified in cattle in France and Lebanon, respectively [3,4]. In those studies, the isolates recovered from animals produced OXA-23 or a combination of OXA-23 and OXA-58 enzymes. In the current study, the A. baumannii isolate produced OXA-24. Within the last years, OXA-24-like enzymes were more commonly detected among A. baumannii isolates from Southern Europe, but also from the USA and the UK. It is noteworthy that no carbapenemaseproducingA. baumanniihadbeen isolated inour twopreceding studies conducted in companion animals from Reunion Island. One hypothesis for the presence of carbapenemase-producing A. baumannii in cattle could be the wide use of antibiotics in foodproducing animals that could be responsible for the selection of resistant bacteria, including carbapenemase-producing A. baumannii. For example, a recent study within the European Union and European Economic Area showed that a wide range of antimicrobial agents is used in these countries (i.e. tetracyclines, penicillins, macrolides, fluoroquinolones and others) [5]. A second interesting result is the diversity of the strains isolated in this study. Indeed, this is not consistent with the hypothesis of the spread of a unique strain from animal to animal, or with the presence of a unique strain in the environment of the farm that could have contaminated all of the animals. It is also noteworthy that the blaOXA-24 gene harboured by the carbapenem-resistant isolate did not disseminate to other A. baumannii isolates collected on the same cattle farm. These results are in accordance with our previous study conducted among pets from Reunion Island, with high strain diversity [2]. Overall, this study tends to confirm in livestock animals the result obtained in our preceding study conducted in pets, that A. baumannii is a micro-organism widely disseminated among animals living on Reunion Island. To our knowledge, this is also the first report of such A. baumannii strain diversity recorded from cattle living in the same environment. Further studies are needed to confirm these results. This study raises some questions: (i) what was the prevalence of A. baumannii carriage in the farm?; (ii) could this prevalence and strain diversity be recovered from all farms on Reunion Island?; and (iii) what could explain the strain diversity recorded in a few animals living in the same environment? Indeed, here the five A. baumannii isolates were assigned to different STs, among which four had never been described previously. This result suggests that a huge diversity of STs could be found in the cattle reservoir, maybe with isolates very different from those isolated in humans. One STs was already described, but has never been reported in the literature as isolated in humans or animals. Therefore, other investigations should be initiated to improve our understanding regarding the extrahospital transmission of these bacteria. Lastly, this first report of carbapenem-resistant A. baumannii in animals in France is a serious cause of concern.