BACKGROUND:Carbapenemase-producing Enterobacterales (CPE) have been designated by the World Health Organization as critical global priority pathogens. Their widespread dissemination and nosocomial outbreaks pose a major public health threat. This study examined the transmission patterns and genetic characteristics of CPE isolated in New Caledonia between 2013 and 2022. METHODS:A total of 214 CPE isolates were collected, comprising 199 non-duplicate clinical isolates from 164 patients and 15 environmental isolates from hospital surfaces. Isolates were characterized using phenotypic methods and whole-genome sequencing. RESULTS:Among clinical isolates, the most prevalent genera was Enterobacter (n = 68; 34%) and Klebsiella (n = 50; 25%), with 194 isolates (98%) harbouring IMP-type carbapenemases. WGS of 89 selected CPE revealed the predominance of the blaIMP-4 gene (n = 82; 92%). This gene was primarily associated with IncM2-type plasmids carrying a class 1 integron, identified in 65 sequenced isolates. Long-read sequencing resolved these plasmids into seven distinct variants, differentiated by integron structures and a 9305-bp insertion. Genomic, phenotypic, and epidemiological triangulation have identified 12 hospital spread events, with 10 linked to IMP-4 IncM2 plasmids, whose transferability is confirmed by conjugation assays. CONCLUSION:These results highlighted the pivotal role of plasmid-mediated dissemination in CPE spread and emphasize the urgency of enhanced surveillance to curb silent transmission. The study provided critical insights for targeted infection control strategies in New Caledonia healthcare system, with broader implications for regional antimicrobial resistance containment.

Leptospires, the etiological agents of leptospirosis, are fastidious slow-growing organisms. Here we describe the isolation and routine maintenance of leptospires from clinical (blood, urine, or tissue) and environmental (water or soil) samples. Using combinations of filtration, agar plating, and selective agents, leptospires can be isolated in pure cultures even from complex contaminated sources in standard EMJH culture medium.

Medical microbiology has used phenotypical and metabolic criteria to identify bacterial pathogens for decades. However, no such criteria have been applied to identify leptospires at the species level. In the recent years, matrix-assisted laser desorption/ionization time-of-flight (MALDI-ToF) mass spectrometry (MS) has emerged as new tool for the identification of bacterial species in the medical microbiology laboratory. This technology has rapidly gained more and more popularity. Actually, this technique is sensitive and economic, saving both labor and bench costs, but also rapid, significantly reducing turnaround time from isolation to identification. MALDI-ToF MS provides an unprecedented tool for the rapid identification of Leptospira at the species level.

Background:Antimicrobial resistance (AMR) issues have emerged in New Caledonia, particularly involving methicillin-resistant Staphylococcus aureus (MRSA), and carbapenem-resistant Acinetobacter baumannii (CR-AB). However, a comprehensive overall picture is still required to guide an antimicrobial stewardship. Methods:A prospective collection of antimicrobial susceptibility testing results was performed over a 20-year period (2005-2024) in the Territorial Hospital Center, the main hospital in New Caledonia. This surveillance encompassed 22 different pathogens and 28 antimicrobial agents, covering 157 pathogen-drug combinations. Resistance rates over time were analyzed using logistic models. A focus was placed on high-priority pathogens, including MRSA, CR-AB, vancomycin-resistant Enterococcus faecium, ceftazidime-resistant Pseudomonas aeruginosa, extended-spectrum β-lactamase Enterobacterales (ESBL-E), and carbapenemase-producing Enterobacterales (CPE). Multidrug-resistant (MDR) and possible extensively drug-resistant (pXDR) isolates were also identified and characterized. Findings:Across 111,022 included isolates, emergences of resistance were observed, notably to penicillins, third-generation cephalosporins, tetracycline, and fusidic acid. Temporal resistance trends were described, along with outbreaks of MRSA and CR-AB, and the emergence of ESBL-E and CPE, representing 3.7% [95% CI: 3.5-3.8] (N = 2208), and 0.1% [95% CI: 0.1-0.2] (N = 85) of the 59,954 Enterobacterales isolates, respectively. Overall, 11% [95% CI: 10.8-11.1] were MDR and 0.6% [95% CI: 0.5-0.6] were pXDR. Interpretation:Through trend analyses, this surveillance highlighted both the emergence and decline of AMR across diverse bacterial pathogens, helping inform which antibiotics may remain appropriate as first-line options and addressing the lack of data from Pacific Island settings. Funding:This work received financial support from the Pierre Ledoux Jeunesse Internationale scholarship (Fondation de France) and the Institut Pasteur, Paris.

Background Leptospirosis is a neglected zoonosis transmitted through urine of infected hosts or contaminated environments. The transmission of bacteria between humans, animals, and the environment underscores the necessity of a One Health approach.Methods We conducted a systematic review to identify significant findings and challenges in One Health research on leptospirosis, focusing on studies involving sampling in >= 2 of the 3 compartments: human, animal, and environment. We searched in PubMed, Web of Science, Medline, Scopus, and ScienceDirect from 1 January 1918 to 31 December 2022. We assessed risk of bias in studies using Joanna Briggs Institute tools and performed a meta-analysis to identify links between One Health compartments.Results Of 1082 leptospirosis studies with sampling, 102 multicompartmental studies conducted between 1972 and 2022 were included: 70 human-Animal, 18 animal-environment, 4 human-environment, and 10 across all compartments. Various methodological weaknesses were identified, from study design to statistical analysis. Meta-regressions identified positive associations between human and animal seroprevalences, particularly with livestock and with wild nonrodent animals, and a link between the environmental positivity rate and domestic animal seroprevalence. Our analysis was constrained by the limited number of studies included and by the quality of protocols.Conclusions This 50-year overview of One Health field approach to leptospirosis highlights the critical need for more robust, well-supported One Health research to clarify the transmission dynamics and identify risk factors of zoonoses. Many studies exhibited methodological weaknesses from the design to the data analysis. Positive associations were found between human and animal, and animal and the environment. One Health is crucial to understand leptospirosis, but rigorous studies are needed.

BackgroundLeptospirosis is a neglected zoonosis. This spirochetal disease is common in tropical countries where rainfall and poor sanitation facilitate skin contact with environmental Leptospira shed in animal urine. Antibiotics are effective against spirochetes, although a harmful Jarisch-Herxheimer (JHR) reaction can occur within hours of treatment, with the onset of chills, fever and/or hypotension. However, the awareness and incidence of JHR in leptospirosis are poorly understood.MethodsThis prospective observational study enrolled 81 patients diagnosed with leptospirosis from four hospitals in New Caledonia between 2021 and 2024. To evaluate the patients' inflammatory status and identify risk factors for JHR, we collected data on clinical, socioeconomic, and biological factors (including blood cytokine levels) at admission and during the hours following treatment with different regimens of β-lactam antibiotics.Main resultsThe majority of the cohort were middle-aged men, most of them Melanesian farmers. They exhibited high levels of C-reactive protein (CRP), neutrophilia, thrombocytopenia, and elevated biochemical markers indicative of liver and kidney dysfunction, which are typical of leptospirosis. Unexpectedly, pro-inflammatory cytokine levels were low or undetectable upon admission, while high levels of the anti-inflammatory cytokine IL-10 were measured. After antibiotherapy, increased levels of the pro-inflammatory cytokines TNF and IL-6, as well as IL-10 were observed. Strikingly, there was no increase in IL-1ß, the main player in the "cytokine storm". JHR, identified with a new clinical score, occurred in 48% (possibly 61%) of patients and was associated with higher cytokine levels, as expected.Conclusion/significanceThis study confirms the stealth nature of leptospires, which induce a potent anti-inflammatory response rather than inflammation. It calls into question both the cytokine storm hypothesis, which is often cited in leptospirosis and the use of immunosuppressive drugs. The high incidence of JHR in New Caledonia suggests that the systematic use of ß-lactams as a first-line treatment should be reevaluated.

Background Leptospirosis is a neglected zoonotic disease prevalent worldwide, particularly in tropical regions experiencing frequent rainfall and severe cyclones, which are further aggravated by climate change. This bacterial zoonosis, caused by the Leptospira genus, can be transmitted through contaminated water and soil. The Pacific islands bear a high burden of leptospirosis, making it crucial to identify key factors influencing its distribution. Understanding these factors is vital for developing targeted policy decisions to mitigate the spread of Leptospira. Methodology/Principal findings This study aims to establish a precise spatio-temporal risk map of leptospirosis at a national scale, using binarized incidence rates as the variable to predict. The spatial analysis was conducted at a finer resolution than the city level, while the temporal analysis was performed on a monthly basis from 2011 to 2022. Our approach utilized a comprehensive strategy combining machine learning models trained on binarized incidences, along with descriptive techniques for identifying key factors. The analysis encompasses a broad spectrum of variables, including meteorological, topographic, and socio-demographic factors. The strategy achieved a concordance metric of 83.29%, indicating a strong ability to predict the presence of contamination risk, with a sensitivity of 83.93%. Key findings included the identification of seasonal patterns, such as the impact of the El Niño Southern Oscillation, and the determination that rainfall and humidity with a one-month lag are significant contributors to Leptospira contamination. Conversely, soil types rich in organic matter may reduce bacterial presence and survival. Conclusions/Significance The study highlights the significant influence of environmental factors on the seasonal spread of Leptospira, particularly in tropical and subtropical regions. These findings are crucial for public health planning, providing insights for targeted policies to reduce leptospirosis, while advanced machine learning models serve as a robust tool for improving disease surveillance, and risk assessment, which ultimately supports the development of an early warning system.

The global priorities in the field of infectious diseases are constantly changing. While emerging viral infections have regularly dominated public health attention, which has only intensified after the COVID-19 pandemic, numerous bacterial diseases have previously caused, and continue to cause, significant morbidity and mortality-deserving equal attention. Three potentially life-threatening endemic bacterial diseases (leptospirosis, melioidosis, and rickettsioses) are a huge public health concern especially in low- and middle-income countries. Despite their continued threat, these diseases do not receive proportionate attention from global health organizations and are not even included on the WHO list of neglected tropical diseases (NTDs). This, in turn, has led to a vicious circle of neglect with continued, yet conceivably preventable, hospitalizations and deaths each year especially in the vulnerable population. This is a call from a group of multi-institutional experts on the urgent need to directly address the circle of neglect and raise support in terms of funding, research, surveillance, diagnostics, and therapeutics to alleviate the burden of these 3 diseases.

La leptospirose, causée par des bactéries de la famille des spirochètes, fait partie des zoonoses bactériennes les plus menaçantes au monde, avec plus d'un million de cas et près de 60 000 décès chaque année. Les recommandations OMS consistent en l'administration d'antibiotiques à dose pleine, quel que soit le stade ou la sévérité de la pathologie. L'antibiothérapie des infections à spirochètes peut déclencher une réaction de Jarisch-Herxheimer (JHR), syndrome inflammatoire transitoire qui survient dans les 24h qui suivent la première dose d'antibiotique. Ce syndrome conjugue l'installation brutale d'une fièvre, de tremblements, de frissons, de myalgies et/ou une hypotension artérielle. Peu étudiée dans la leptospirose, la JHR peut entrainer une aggravation de l'état du patient. Sur notre territoire, certains centres de santé appliquent un protocole d'introduction par doses croissantes d'antibiotiques pour limiter l'incidence de la JHR. Des anti-inflammatoires stéroïdiens y sont parfois associés.Il existe très peu de données de l'effet de ces différents traitements sur l'incidence de la JHR ni de leur impact sur l'évolution de la pathologie. Le projet LEPJAR-NC, étude prospective observationnelle, a pour but d'évaluer l'incidence de la JHR chez les patients atteints de leptospirose en recueillant des données cliniques et biologiques au moment de la suspicion de leptospirose et dans les 6 heures suivant l'initiation de l'antibiothérapie. Les données obtenues fourniront également des informations sur l'efficacité et l'inocuité des protocoles thérapeutiques. Depuis décembre 2021, 77 patients ayant eu une leptospirose confirmée par PCR ont été inclus dans le projet LEPJAR-NC. Une méthode de scoring-JHR a été mise au point et validée par les collaborateurs de l'étude. Le pourcentage de patients ayant développé une JHR est supérieur à 50%, contre les 9 à 12% décrits dans la littérature. Les niveaux de cytokines pro- (IL-6 et TNF-a) et anti- (IL-10) inflammatoires augmentent significativement au cours des heures qui suivent la première prise d'antibiotiques chez les patients ayant fait une JHR. Ces niveaux de cytokines sont moins élevés lorsque le protocole à doses croissantes est mis en place. Les données cliniques et biologiques sont encore en cours de recueil et les inclusions se poursuivent. Les données de ce projet permettront d'estimer l'incidence de la JHR chez les patients atteints de leptospirose et de standardiser les critères de définition de la JHR, en partie grâce à des biomarqueurs non considérés à ce jour. Nos résultats permettront aussi de mieux estimer les risques associés à cette réaction et d'harmoniser les pratiques de prise en charge. Aucun lien d'intérêt

Life-threatening Leptospira interrogans navigate a dual existence: surviving in the environment and infecting mammalian hosts. Biofilm formation is presumably an important survival strategy to achieve this process. Understanding the relation between biofilm and virulence might improve our comprehension of leptospirosis epidemiology. Our study focused on elucidating Leptospira’s adaptations and regulations involved in such complex microenvironments. To determine the transcriptional profile of Leptospira in biofilm, we compared the transcriptomes in late biofilms and in exponential planktonic cultures. While genes for motility, energy production, and metabolism were downregulated, those governing general stress response, defense against metal stress, and redox homeostasis showed a significant upsurge, hinting at a tailored defensive strategy against stress. Further, despite a reduced metabolic state, biofilm disruption swiftly restored metabolic activity. Crucially, bacteria in late biofilms or resulting from biofilm disruption retained virulence in an animal model. In summary, our study highlights Leptospira’s adaptive equilibrium in biofilms: minimizing energy expenditure, potentially aiding in withstanding stresses while maintaining pathogenicity. These insights are important for explaining the survival strategies of Leptospira, revealing that a biofilm lifestyle may confer an advantage in maintaining virulence, an understanding essential for managing leptospirosis across both environmental and mammalian reservoirs.

Background Leptospirosis is a neglected zoonosis which remains poorly known despite its epidemic potential, especially in tropical islands where outdoor lifestyle, vulnerability to invasive reservoir species and hot and rainy climate constitute higher risks for infections. Burden remains poorly documented while outbreaks can easily overflow health systems of these isolated and poorly populated areas. Identification of generic patterns driving leptospirosis dynamics across tropical islands would help understand its epidemiology for better preparedness of communities. In this study, we aim to model leptospirosis seasonality and outbreaks in tropical islands based on precipitation and temperature indicators. Methodology/Principal findings We adjusted machine learning models on leptospirosis surveillance data from seven tropical islands (Guadeloupe, Reunion Island, Fiji, Futuna, New Caledonia, and Tahiti) to investigate 1) the effect of climate on the disease’s seasonal dynamic, i.e., the centered seasonal profile and 2) inter-annual anomalies, i.e., the incidence deviations from the seasonal profile. The model was then used to estimate seasonal dynamics of leptospirosis in Vanuatu and Puerto Rico where disease incidence data were not available. A robust model, validated across different islands with leave-island-out cross-validation and based on current and 2-month lagged precipitation and current and 1-month lagged temperature, can be constructed to estimate the seasonal dynamic of leptospirosis. In opposition, climate determinants and their importance in estimating inter-annual anomalies highly differed across islands. Conclusions/Significance Climate appears as a strong determinant of leptospirosis seasonality in tropical islands regardless of the diversity of the considered environments and the different lifestyles across the islands. However, predictive and expandable abilities from climate indicators weaken when estimating inter-annual outbreaks and emphasize the importance of these local characteristics in the occurrence of outbreaks.

Carbapenemase-producing Enterobacterales (CPE) have been identified by the World Health Organization as global priority pathogens. The dissemination of these bacteria and outbreaks within healthcare facilities are of serious concern. This study investigated the transmission patterns and genetic characteristics of CPE isolated in New Caledonia from 2013 to 2022. The isolates were identified and characterized both phenotypically and whole-genome sequencing (WGS). In total 214 CPE were isolated: 199 non duplicate clinical isolates from 164 patients and 15 from hospital environmental surface. The most common genera in clinical samples were Enterobacter (34%) and Klebsiella (25%), with 194 isolates (98%) carrying IMP-type carbapenemase. WGS of 89 isolates revealed the dominance of the blaIMP-4 carbapenemase gene, found in 82 isolates. The blaIMP-4 was primarily predicted to be carried by IncL/M-type plasmid, found in 69% of the sequenced isolates. Our work revealed the circulation of 12 bacterial clusters with 61 strains involved in outbreaks or persistent over time. Genomic, phenotypic and clinical approaches identified 12 distinct outbreaks involving IMP producers. These results highlight the importance of studying plasmid transmission to better prevent silent spread of CPE. Ultimately, this study provides new guidelines for limiting the clinical spread of CPE in New Caledonia.

Leptospirosis is a zoonosis caused by Leptospira bacteria present in the urine of mammals. Leptospira is able to survive in soils and can be resuspended during rain events. Here, we analyzed the pathogenic Leptospira concentration as a function of hydrological variables in a leptospirosis hot spot. A total of 226 samples were collected at the outlet of a 3 km2 watershed degraded by ungulate mammals (deer and feral pigs) and rats which are reservoirs for leptospirosis. Water samples collected at the beginning of a rain event following a dry period contained high concentrations of pathogenic Leptospira. The concentration was generally correlated with the water level and the suspended matter concentration (SMC) during the main flood event. A secondary peak of pathogenic Leptospira was sometimes detected after the main flood and in slightly turbid waters. Lastly, the pathogenic Leptospira concentration was extremely high at the end of a wet season. The pathogenic Leptospira concentrations could not be explained by a linear combination of hydrological variables (e.g. the rainfall, water level, SMC and soil moisture). However, nonlinear machine learning models of rainfall data only provided a fair fit to the observations and explained 75 % of the variance in the log10-transformed pathogenic Leptospira concentration. A comparison of identical machine learning models for the water level, SMC and pathogenic Leptospira concentration showed that the residual error in the Leptospira concentration was due to not only the small dataset but also the intrinsic characteristics of the signal. Our results support the hypothesis whereby pathogenic Leptospira survive at different depths in soils and superficial river sediments (depending on their water saturation) and are transferred to surface water during erosion. These results might help to refine leptospirosis warnings given to the local population. Future research should be focused on larger watersheds in more densely populated areas.

Leptospira is a complex bacterial genus which biodiversity has long been overlooked. In the recent years however, environmental studies have contributed to shed light on its original and current environmental habitat. Although very fragile bacteria in laboratories, Leptospira have been shown to successfully occupy a range of soil and freshwater habitats. Recent work has strongly suggested that biofilm formation, a multicellular lifestyle regulated by the second messenger c-di-GMP, might be one strategy developed to overcome the multiple challenges of environmental survival. Within the genus, a minority of pathogenic species have developed the ability to infect mammals and be responsible for leptospirosis. However, most of them have retained their environmental survival capacity, which is required to fulfill their epidemiological cycle. Indeed, susceptible hosts, such as human, suffer from various symptoms, while reservoir hosts stay asymptomatic and release bacteria in the environment. In this review, we discuss how c-di-GMP might be a central regulator allowing pathogenic Leptospira to fulfill this complex life cycle. We conclude by identifying knowledge gaps and propose some hypotheses that should be researched to gain a holistic vision of Leptospira biology.

Leptospirosis is a zoonosis caused by pathogenic Leptospira shed in the urine of mammals, able to survive in water and soils and remobilized during rainy events. Pathogenic Leptospira (PL) concentrations were measured together with hydrological variables in the upper Thiem river, near the Touho village, a hot spot for leptospirosis in the main island of New Caledonia (a small tropical island itself a hot spot for leptospirosis). Two hundred twenty-six water samples were collected at the outlet of as 3 km2 sub-watershed, which is frequented by invasive mammals (rodents, deer and wild pigs) known to be animal reservoirs for leptospirosis. The main features of our results highlight that (i) samples collected at the beginning of a rain event occurring after a dry period may contain high PL concentrations (ii) PL concentrations at the heart of a wet period exhibit significant correlation with rainfall, water level and suspended matter concentration (SMC) (iii) elevated PL concentration may be observed a few days after the main flood event and within weakly turbid waters, (iV) the largest PL concentrations were observed in the middle and at the end of a wet rain season. Comparison of PL concentrations with hydrological data (rainfall, water level, SMC, soil moisture) reveals that they cannot be explained by a linear combination of hydrological variables. Indeed, nonlinear machine learning models provided a fair fit to observed data (99% of explained variance on their decimal logarithm and a mean ratio of 2.5 between raw observed data and modeled values). Comparison of identical machine learning models of water levels, SMC and PL concentration shows that the remaining error in PL concentration data does not only result from the limited dataset but rather from the intrinsic characteristics of the Leptospira signal. Our results may help to refine recommendations for leptospirosis control towards local populations. Further studies in larger watersheds draining in more populated areas will be conducted to confirm and extend these findings

The increase in carbapenem-resistant Enterobacterales (CRE) is mostly driven by the spread of carbapenemase-producing (CP) strains. In New Caledonia, the majority of carbapenemases found are IMP-type carbapenemases that are difficult to detect on routine selective media. In this study, a culture-based method with ertapenem selection is proposed to distinguish non-CRE, non-CP-CRE, and CP-CRE from samples with very high bacterial loads. Firstly, assays were carried out with phenotypically well-characterized β-lactam-resistant Enterobacterales isolates. Then, this approach was applied to clinical and environmental samples. Presumptive CP-CRE isolates were finally identified, and the presence of a carbapenemase was assessed. In a collection of 27 phenotypically well-characterized β-lactam-resistant Enterobacterales, an ertapenem concentration of 0.5 µg·mL−1 allowed distinguishing CRE from non-CRE. A concentration of 4 µg·mL−1 allowed distinguishing CP-CRE from non-CP-CRE after nine hours of incubation. These methods allowed isolating 18 CP-CRE from hospital effluents, including the first detection of a KPC in New Caledonia. All these elements show that this cost-effective strategy to distinguish β-lactam-resistant Enterobacterales provides fast and reliable results. This could be applied in the Pacific islands or other resource-limited settings, where limited data are available.

OBJECTIVE:Carbapenemase-producing Enterobacteriaceae (CRE) and Enterococcus faecium resistant to vancomycin (VRE) constitute major threats to public health worldwide. The Pacific area is concerned and has implemented strategies to control antimicrobial resistance (AMR). However, accurate epidemiological data are rarely reported. Our study aimed to present the strategies applied to prevent and control the spread of highly resistant bacteria in the Pacific territory of New Caledonia.PATIENTS AND METHODS:Cohort prospective study of all cases of highly resistant bacteria (HRB) isolated in New Caledonia from September 2004 to December 2020. Evaluation of the impact of the infection control measures implemented in healthcare settings: screening strategy, cohorting unit, IT tools and control of antibiotic prescriptions.RESULTS:A total of 346 patients with HRB were identified. Most of them (63.0%) were infected or colonized by VRE (n=218) and 128 by CRE. While the number of CREs significantly increased from 2013 to 2020 (P<0.0001), control procedures have limited their dissemination. Most patients were colonized by IMP-4-CRE (n=124/128). The incidence density of VRE significantly decreased from 38.52 for 100,000 hospitalisation-days in 2015 to 4.19 for 100,000 hospitalisation-days in 2019 due to systematic screening of patients before sanitary repatriation from Australia and cohorting implementation. The risk of VRE diffusion is now well under control.CONCLUSIONS:Our study confirms that it is possible to control the spread of AMR in a circumscribed territory by means of a global control strategy involving screening, cohorting unit, IT tools and antibiotic prescription controls.

OBJECTIVES:Since 2014, Staphylococcus aureus methicillin resistance has been rapidly increasing in New Caledonia and is associated with potential serious clinical repercussions. In the present study, we investigated the epidemiology of methicillin-resistant S. aureus (MRSA) in New Caledonia and the possible emergence of a particular clonal strain.METHODS:An overview of the distribution of MRSA in New Caledonia in 2019 is presented. We collected and analysed 171 clinical MRSA isolates from New Caledonia medical laboratories during August and September 2019. Among this collection, 49 representative isolates were analyzed by the French National Reference Center for Staphylococci using the StaphyType DNA microarray, allowing genetic characterization of the isolates.RESULTS:Among the 1144 S. aureus isolated over the year 2019, 442 isolates (39%) were resistant to methicillin, and 62% of these isolates were resistant to fusidic acid (FA). During the inclusion period, FA resistance rate was similar (60%). Genetic characterization evidenced CC6 as the predominant clonal complex (70%) with 26 isolates (53%) identified as CC6-MRSA-[IV+fus] (PVL+).CONCLUSIONS:These findings demonstrated a low diversity of MRSA in New Caledonia, with the dominance of a clonal complex not reported previously. The frequent fusidic acid (FA) resistance in MRSA was associated with a high prevalence of fusC gene, suggesting that FA misuse contributed to driving the selection of this clone. Our findings suggest the recommendation to stop the topical use of FA to control the emergence of this severe MRSA clone and decrease the rate of MRSA in New Caledonia.