Search

To describe Staphylococcus lugdunensis prosthetic joint infection (PJI) management and outcome.Adults with proven S. lugdunensis PJI were included in a multicentric retrospective cohort. Determinants for failure were assessed by logistic regression and treatment failure-free survival curve analysis (Kaplan-Meier).One hundred and eleven patients were included (median age 72.4 [IQR, 62.7-79.4] years), with a knee (n = 71, 64.0%) or hip (n = 39, 35.1%) PJI considered as chronic in 77 (69.4%) cases. Surgical management consisted in debridement, antibiotic with implant retention (DAIR; n = 60, 54.1%), two-stage (n = 28, 25.2%) or one-stage (n = 15, 13.5%) exchange. Total duration of antimicrobial therapy was 13.1 (IQR, 11.8-16.9) weeks. After a median follow-up of 99.9 (IQR, 53.9-178.1) weeks, 22 (19.8%) S. lugdunensis-related treatment failures were observed. Independent determinants for outcome were diabetes (OR, 3.741; p = 0.036), sinus tract (OR, 3.846; p = 0.032), DAIR (OR, 3.749; p = 0.039) and rifampin-based regimen (OR, 0.319; p = 0.043). Twenty-four (40.0%) of the 60 DAIR-treated patients experienced treatment failure, with hip location (OR, 3.273; p = 0.048), delay from prosthesis implantation (OR, 1.012 per month; p = 0.019), pre-surgical CRP level115 mg/L (OR, 4.800; p = 0.039) and mobile component exchange (OR, 0.302; p = 0.069) constituting additional determinants of outcome.Staphylococcus lugdunensis PJI are difficult-to-treat infections, with pivotal roles of an optimal surgical management.

The coronavirus disease 2019 (COVID-19) pandemic has radically altered priorities and planning in the global medical community with continuously increasing numbers of infected patients. Cardiovascular disease accounts for the most common comorbidity encountered in patients with COVID-19. Infective endocarditis (IE) represents a grave medical condition as it may compromise circulatory homeostasis, renal function, and lead to embolic complications. COVID-19 also causes coagulopathy-associated complications. In this report we describe the case of a patient presenting to the accident and emergency department with fever and chills. COVID-19 was confirmed and further workup revealed concomitant severe native valve IE with Staphylococcus lugdunensis. Medical community worldwide should remain alert and continue working towards early recognition of these intricate interactions.

Staphylococcus lugdunensis infective endocarditis (IE) is very rare in children. A female neonote presented with fever on the 29th postoperative day after undergoing a modified Norwood procedure (right ventricular-pulmonary artery [RV-PA] conduit). Blood cultures were positive for S. lugdunensis. Echocardiography did not demonstrate vegetation. Therefore, we made a diagnosis of catheter-related bacteremia instead of IE. Cultures were negative 3 days after treatment initiation with intravenous vancomycin. One month after discharge, she developed acute hypoxia and could not be revived because of obstruction of RV-PA conduit with large vegetation. Even in S. lugdunensis bacteremia without IE, surgical treatment should be considered early.

Background Staphylococcus lugdunensis is a commensal skin microorganism that, unlike other coagulase-negative staphylococci, presents increasing clinical importance. This species yields a metalloprotease called lugdulysin that may contribute to its higher degree of virulence. This study aimed to determine the biochemical characterization of the lugdulysin produced by S. lugdunensis clinical isolates and investigate its effect on the formation and disruption of biofilm of Staphylococcus aureus isolates. The protease was isolated and characterized for its optimal pH and temperature, activity in the presence of inhibitors and enzymatic kinetics. The influence of metal cofactor supplementation on proteolysis was also evaluated, with and without inhibitors. Finally, the protease capacity to inhibit and disrupt biofilms of different S. aureus lineages and biofilm matrix was analyzed. Results The protease optimal pH and temperature were 7.0 and 37° C, respectively. EDTA inhibited the protease, and the activity was not recovered by divalent ion supplementation. In addition, divalent ions did not change enzymatic activity without inhibitors, which was stable for up to 3 hours. Its structure was determined via homology modelling. The protease significantly inhibited the formation and disrupted established biofilms of S. aureus isolates with protein biofilm. Conclusions This study confirmed features of the lugdulysin metalloprotease and showed that this S. lugdunensis virulence factor may be a new competition mechanism and/or modulation of the staphylococcal biofilm.

Purpose of Review This article presents a comprehensive narrative review of reactive arthritis (ReA) with focus on articles published between 2018 and 2020. We discuss the entire spectrum of microbial agents known to be the main causative agents of ReA, those reported to be rare infective agents, and those reported to be new candidates causing the disease. The discussion is set within the context of changing disease terminology, definition, and classification over time. Further, we include reports that present at least a hint of effective antimicrobial therapy for ReA as documented in case reports or in double-blind controlled studies. Additional information is included on microbial products detected in the joint, as well as on the positivity of HLA-B27. Recent Findings Recent reports of ReA cover several rare causative microorganism such as Neisseria meningitides, Clostridium difficile, Escherichia coli, Hafnia alvei, Blastocytosis, Giardia lamblia, Cryptosporidium, Cyclospora cayetanensis, Entamoeba histolytica/dispar, Strongyloides stercoralis, β-haemolytic Streptococci, Mycobacterium tuberculosis, Mycoplasma pneumoniae, Mycobacterium bovis bacillus Calmette-Guerin, and Rickettsia rickettsii. The most prominent new infectious agents implicated as causative in ReA are Staphylococcus lugdunensis, placenta- and umbilical cord–derived Wharton’s jelly, Rothia mucilaginosa, and most importantly the SARS-CoV-2 virus. Summary In view of the increasingly large spectrum of causative agents, diagnostic consideration for the disease must include the entire panel of post-infectious arthritides termed ReA. Diagnostic procedures cannot be restricted to the well-known HLA-B27-associated group of ReA, but must also cover the large number of rare forms of arthritis following infections and vaccinations, as well as those elicited by the newly identified members of the ReA group summarized herein. Inclusion of these newly identified etiologic agents must necessitate increased research into the pathogenic mechanisms variously involved, which will engender important insights for treatment and management of ReA. Supplementary Information The online version contains supplementary material available at 10.1007/s11926-021-01018-6.

Staphylococcus lugdunensis is an emerging coagulase-negative Staphylococcus regarded as a formidable pathogen capable of causing significant infections at various body sites including bone and joints. We report the case of a Caucasian elderly male with recurrent lumbar osteomyelitis due to S. lugdunensis. He had a history of chronic low back pain. Besides chronic kidney failure and need for hemodialysis, he had no other history of immunosuppression. He did not have fever or leukocytosis; however, the erythrocyte sedimentation rate was elevated, and repeated blood cultures from the periphery and the hemodialysis access (tunneled catheter) were continuously positive for S. lugdunensis. The diagnosis was made by bone biopsy and culture. The bacteremia cleared after removing of the dialysis catheter. The patient received 8 weeks of antibiotic therapy for the osteomyelitis.

Tubo-ovarian abscess may develop in women with endometrioma following assisted reproductive technology (ART). The infection, though rare, is typically late in onset and may present several months after the procedure, and in pregnancy—with the risks of abortion and premature labor. It is thought that transcutaneous oocyte retrieval during ART is the route for bacterial contamination resulting in infection of the endometrioma. Pathogens reported in the literature includeEscherichia coli(E. coli) and Group B streptococcus (GBS) butStaphylococcus lugdunensis(S. lugdunensis), a coagulase-negative staphylococcus (CoNS), and groin and perineal skin commensal was isolated from the endometrioma in this case. We discuss the challenges in diagnosis and treatment of this rare condition and the implications of the discovery that an organism previously dismissed as a contaminant has emerged as a causative organism in severe, deep-seated infections of soft tissues in recent literature.

Background Progress in contemporary medicine is associated with an increasing number of immunocompromised individuals. In this vulnerable group, the underlying disease together with long-term hospitalization and the use of medical devices facilitate infections by opportunistic pathogens, of which coagulase-negative staphylococci (CoNS) represent a prime example. Objectives The diversity of CoNS with species- and strain-specific differences concerning virulence and clinical impact is highlighted. A focus is on the ability of CoNS to generate biofilms on biotic and abiotic surfaces, which enables skin and mucosa colonization as well as establishment of CoNS on indwelling foreign bodies. Sources Literature about the virulence of CoNS listed in PubMed was reviewed. Content Most catheter-related and prosthetic joint infections as well as most other device-related infections are caused by CoNS, specifically by Staphylococcus epidermidis and Staphylococcus haemolyticus. A common theme of CoNS infections is a high antibiotic resistance rate, which often limits treatment options and contributes to the significant health and economic burden imposed by CoNS. Implications Breaching the skin barrier along with the insertion of medical devices offers CoNS opportunities to gain access to host tissues and to sustain there by forming biofilms on foreign body surfaces. Biofilms represent the perfect niche to protect CoNS from both the host immune response and the action of antibiotics. Their particular lifestyle, combined with conditions that facilitate host colonization and infection, has led to the growing impact of CoNS as pathogens. Moreover, CoNS may serve as hidden reservoirs for antibiotic resistance and virulence traits.

Methicillin-resistant Staphylococcus lugdunensis (MRSL) is increasingly recognized in healthcare and community settings. To obtain a better understanding of the emergence of MRSL, this study characterized the structure and content of the SCCmec elements harboured by 36 MRSL isolates obtained from diverse sources in Hong Kong from 2008 to 2017. The isolates were investigated by whole-genome sequencing. SCCmec types and subtypes were assigned according to the guidelines from the International Working Group on the Classification of Staphylococcal Cassette Chromosome Elements. The sequence type (ST)–SCCmec combinations in the 36 MRSL isolates were as follows: ST3–SCCmec IV (n=2), ST3–SCCmec V (n=28), ST27–SCCmec V (n=5) and ST42–SCCmec V (n=1). The two SCCmec IV elements were highly similar to the SCCmec IV element harboured by the community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strain, JCSC6668. The J3–mec complex–J2 regions in the SCCmec V elements were highly similar to the corresponding regions in the CA-MRSA strains PM1 (n=13) or WIS (n=21). Based on the J1 to J3 sequences, the SCCmec V elements can be categorized into nine different subtypes. Our findings highlight the diversified structures of SCCmec elements among MRSL strains and their close relationship with SCCmec elements harboured by CA-MRSA.

Nosocomial infections, also known as health care-associated infections (HAIs) are infections that appear in patients under medical care in hospitals or other health care facilities and were absent at the time of admission. From 5 to 7 thousand cases of HAIs are registered in Ukraine every year, but according to experts, the actual number is 900 thousand cases per year. Intensive care unit (ICU) represents a prominent tool in HAIs control and quality assurance in many developed countries. In this respect, the US Center for Disease Control and Prevention (CDC) recommends monitoring HAI as a leading tool for the reduction of HAIs. Therefore, the aim of this research was to investigate microbiological profile of nosocomial infections in ICU of public hospitals in Lviv, Ukraine. Material and methods. 105 clinical materials from 50 patients in two public hospitals in Lviv (Lviv Regional clinical hospital and Military Medical Clinical Center of the Western Region) were analyzed during July-December 2018. 114 strains of pathogens were isolated. HAIs was defined as an infection that appeared in patients later than 48 hours after admission to the hospital. Urinary tract infections (UTI), blood stream infection (BI), respiratory tract infection (RTI) and surgical site infections (SSI) were diagnosed using the criteria defined by the CDC and clinical protocols. Causative bacterial strains were isolated and identified using standard methods and chromogenic media CHROMID*S.aureusElite, CHROMID*VRE, CHROMID*MRSASMART, CHROMID*CARBASMART, CHROMID* ESBL, CHROMID*OXA-48, CHROMID*Candida (Biomerieux) and biochemical identification kitsMIKRO-LA-TESTNEFERMtest24, ENTEROtest24, CANDIDAtest21, STAPHYtest24, STREPTOtest24 (ErbaLacema, Czech Republic). Antibiotic sensitivity test was done using Kirby-Bauer disc diffusion technique. (Ethical Committee or Institutional Animal Care and Use Committee Approval Danylo Halytsky Lviv National Medical University: 25/06/2018 № 6). HAIs structure was as follows: Staphylococcus lentus (22%), Eschrichia coli (22%), Klebsiella pneumoniae subsp.ozaenae (9.8%), Pseudomonas aeruginosa (43.9%), Klebsiella pneumoniae subsp.pneumonia (8.8%), Srreptococcus spp. (7.0%), Burkholderia pseudomallei (5.3%), Staphylococcus haemolyticus (3.5), Staphylococcus aureus (3.5%). There were several types of HAIs which are rarely found, such as Staphylococcus lentus, Staphylococcus simulans, Staphylococcus lugdunensis, Aerococcus viridans, Pragia fontium, Aeromonasichthiosmia, Raoultella terrigena, Macrococcus caseolyticus. Conclusions. In the era of antibiotics, HAIs are still uncontrollable. It is assessed that over 90.0% of HAIs are not recognized as epidemics. It is important to remember this fact when attempting to design prevention or control strategy to reduce HAIs either at WHO level, or at the level of local health care unit.

The increasing production of goat milk and its derivatives is affected by the occurrence of intramammary infections, which are highly associated with the presence of Staphylococcus species, including some with zoonotic potential. Staphylococci in general can exchange mobile genetic elements, a process that may be facilitated by the isolate's capacity of forming biofilms. In this study we identified, to the species level, Staphylococcus isolated from goat milk samples by MALDI-TOF and confirmed the identification by sequencing housekeeping genes (rrs and tuf). Eight species were identified, more than half being either Staphylococcus epidermidis or Staphylococcus lugdunensis. The isolates were shown by pulsed-field gel electrophoresis to be genetically diverse between the studied herds. Resistance to ampicillin and penicillin was widespread, and 2 Staph. epidermidis isolates contained the methicillin-resistance gene mecA. Most of the isolates that were resistant to at least 1 of the 13 antimicrobials tested harbored plasmids, one of which was demonstrated to be conjugative, being transferred from a Staph. epidermidis to a Staphylococcus aureus strain. Biofilm formation was observed in almost every isolate, which may contribute to their capacity of exchanging antimicrobial resistance genes in addition to acting as a physical barrier to the access of drugs. Our results showed that antimicrobial resistance among goat staphylococci may be emerging in a process facilitated by the exchange of mobile genetic elements between the bacteria and the establishment of biofilms, which calls for careful monitoring and more effective control therapies.

Staphylococcus lugdunensis is a coagulase-negative staphylococcus (CoNS) with unusual pathogenicity resembling that of S. aureus. Unlike other CoNS, S. lugdunensis remains susceptible to most antibiotics. The resistance to penicillin varies widely (range, 15–87% worldwide), whereas methicillin resistance is still rare. We aimed to evaluate treatment options for infections caused by S. lugdunensis and more specifically to investigate whether penicillin G could be a better treatment choice than oxacillin. Susceptibility testing was performed using the disc diffusion method for penicillin G, cefoxitin, trimethoprim/sulfamethoxazole, erythromycin, clindamycin, gentamicin, norfloxacin, fusidic acid, rifampicin, and fosfomycin. Isolates susceptible to penicillin G were further tested with a gradient test for penicillin G and oxacillin. Of the 540 clinical isolates tested, 74.6% were susceptible to penicillin G. Among these penicillin-susceptible isolates, the MIC50 and MIC90 values for penicillin G were threefold lower than that for oxacillin. A majority of the isolates were susceptible to all other antibiotics tested. Breakpoints for fosfomycin have not yet been defined, and so no conclusions could be drawn. Two isolates were resistant to cefoxitin and carried the mecA gene; whole-genome sequencing revealed that both harbored the SCCmec element type IVa(2B). S. lugdunensis isolated in Sweden were susceptible to most tested antibiotics. Penicillin G may be a more optimal treatment choice than oxacillin. Although carriage of the mecA gene is rare among S. lugdunensis, it does occur. Electronic supplementary material The online version of this article (10.1007/s10096-019-03571-6) contains supplementary material, which is available to authorized users.

Background Staphylococcus lugdunensis is a significant pathogen that causes community-acquired and nosocomial infections. The high prevalence of oxacillin-resistant S. lugdunensis (ORSL) is of major concern. Resistance to β-lactams is caused by acquisition of the staphylococcal cassette chromosome mec (SCCmec) element. The cassette is highly diverse, both structurally and genetically, among CoNS. Isolates carrying SCCmec II-ST6 are the major persistent clones in hospitals. Objectives To investigate the structure and evolutionary origin of a novel type II SCCmec element in an endemic ST6 S. lugdunensis clone. Methods The structure of the SCCmec II element carried by ST6 strain CGMH-SL118 was determined by WGS and compared with those reported previously. Results A novel 39 kb SCCmec element, SCCmecCGMH-SL118, with a unique mosaic structure comprising 41 ORFs integrated into the 3′ end of the rlmH gene, was observed. Some regions of SCCmecCGMH-SL118 were homologous to SCCmec IIa of the prototype MRSA strain N315. The structure of SCCmecCGMH-SL118 was similar to that of SCCmec IIb of the MRSA strain, JCSC3063, mainly lacking the aminoglycoside resistance determinant pUB110 in the J3 region but containing the insertion sequence IS256 in the J2 region. Notably, SCCmecCGMH-SL118 deletions in the J1 region compared with SCCmec types IIa and IIb, and a high homology to SCCmec elements of Staphylococcus aureus JCSC4610 and Staphylococcus haemolyticus strain 621 were found. Conclusions The genetic diversity of the type II SCCmec element in ORSL suggests that CoNS is a potential reservoir for interspecies transfer of SCCmec to S. aureus in hospitals.

Background. Surgery for gynecologic cancer with lymphadenectomy and pelvic radiotherapy can produce lymphoceles that sometimes complicate with infection, resulting in abscesses. The true pathogenic bacteria of abscesses are not always found because of false-negative results due to administered antibiotics and difficulty with detection, including for anaerobic bacteria. Analyzing bacteria flora by next-generation sequencing (NGS) using 16S ribosomal DNA may reveal the true pathogenic bacteria in abscesses. This is the first report on causative pathogens for infectious lymphocele using this technology. Methods. The subjects were patients who developed infectious lymphocele after surgery for gynecologic cancer at our hospital from July 2015 to September 2016. NGS analyses of bacterial flora were performed using specimens preserved at -80°C. Two steps of PCR were performed for purified DNA samples to obtain sequence libraries. Processing of sequence data, including operational taxonomic unit (OTU) definition, taxonomy assignment, and an OTU BLAST search were performed. All patients gave written informed consent and the study was approved by the institutional research ethics committee. Results. Six patients underwent puncture and drainage. The result in most cases indicated a single causative pathogen, including Staphylococcus lugdunensis, Streptococcus dysgalactiae, Streptococcus equinus, Enterococcus saccharolyticus, and Escherichia coli. Conclusions. NGS revealed that the causative bacteria in lymphocele infection are normally a single strain, such as a surface Gram-positive coccus or enteric bacteria. Antibiotics should be chosen as appropriate for elimination of these respective bacteria.

Introduction: Staphylococcus lugdunensis is a skin commensal and its association with bone infections is rare. This case is first of its kind in literature where phalangeal osteomyelitis was caused by S. lugdunensis. Case Report: A 56-year-old man presented with a chronic history of index fingertip pain to the orthopedic clinic. There was a partial resolution of symptoms earlier when commenced on anti-inflammatory and antibiotics in community by the general practitioner. A thorough clinical and radiological evaluation followed by a surgical debridement completely cured his symptoms. S. lugdunensis was isolated on culture in this case. Conclusion: Chronic finger-tip infections can be quite challenging to treat and one should have a high index of suspicion in treating such infections, especially with respect to the virulence of commensal micro-organisms.

Introduction: Staphylococcus lugdunensis (SL), a tube coagulase negative Staphylococcus , is known to be pathogenic in adults, causing mainly skin infections. Gap Statement: Previous studies assessing SL's role in paediatric populations are sparse and are mainly limited to case reports. Aim: Present the clinical characteristics consistent with SL infections and its putative role as a pathogen in the paediatric population. Methodology: A retrospective multicentre study was conducted in four paediatric medical centres in Israel. Patients with isolates of SL presenting between 2009–2019 were included. Results: SL was isolated from 40 patients. Average (±SD) age at presentation was 5.9 (±6.2) years, with 22 (55 %) being female. Skin, soft tissue and musculoskeletal infections were the most common (n=20, 50%) followed by ear infections (n=13, 32.5%). Five cases of urine isolates and two isolates from blood culture samples were also reported. Skin abscess was the most common infection among skin and soft tissue isolates, reported in 17 children (85%) with SL being the only pathogen in 15 (75%). Otitis media was the most common ear infection accounting for 12 (92%) of all cases with SL as the only isolate reported in 6 (46%). Five cases of SL isolates from urine specimens were reported, all of which with poor growth of bacteria and normal urinalysis. Two cases of SL growth in blood culture were found in children presenting with signs and symptoms consistent with invasive blood stream infection. Conclusions: In the paediatric population, studied infections caused by SL are increasingly observed. The results of this study highlight its role as a pathogen in soft tissue infections and its putative role in otitis media and invasive blood stream infections. However, the role of SL as an uropathogen was not established.

Biofilm formation by

Staphylococcus lugdunensis is a species of coagulase-negative staphylococcus (CoNS) that causes serious infections in humans akin to those of S. aureus. It was often misidentified as S. aureus, but this has been rectified by recent routine use of matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) in diagnostic laboratories. It encodes a diverse array of virulence factors for adhesion, cytotoxicity, and innate immune evasion, but these are less diverse than those encoded by S. aureus. It expresses an iron-regulated surface determinant (Isd) system combined with a novel energy-coupling factor (ECF) mechanism for extracting heme from hemoproteins. Small cytolytic S. lugdunensis synergistic hemolysins (SLUSH), peptides related to phenol-soluble modulins of S. aureus, act synergistically with β-toxin to lyse erythrocytes. S. lugdunensis expresses a novel peptide antibiotic, lugdunin, that can influence the nasal and skin microbiota. Endovascular infections are initiated by bacterial adherence to fibrinogen promoted by a homologue of Staphylococcus aureus clumping factor A and to von Willebrand factor on damaged endothelium by an uncharacterized mechanism. S. lugdunensis survives within mature phagolysosomes of macrophages without growing and is released only following apoptosis. This differs fundamentally from S. aureus, which actively grows and expresses bicomponent leukotoxins that cause membrane damage and could contribute to survival in the infected host. S. lugdunensis is being investigated as a probiotic to eradicate S. aureus from the nares of carriers. However, this is contraindicated by its innate virulence. Studies to obtain a deeper understanding of S. lugdunensis colonization, virulence, and microbiome interactions are therefore warranted.

Staphylococcus lugdunensis has been reported to cause a wide variety of serious infections to include infective endocarditis, peritonitis and osteomyelitis. This report describes our patient who developed aorto bifemoral graft infection with Staphylococcus lugdunensis not previously described in the literature. Bangladesh Crit Care J September 2021; 9 (2): 116-117

During the infectious process, pathogens such as Staphylococcus lugdunensis have to cope with the condition of host-induced iron-limitation. Using the RNAseq approach, we performed the first global transcriptomic analysis of S. lugdunensis cells incubated in the absence and presence of iron chelator. One hundred and seventy-five genes were identified as members of the iron-limitation stimulon (127 up- and 48 downregulated). Six gene clusters known or likely required for the acquisition of iron have been identified. Among them, a novel Energy-Coupling Factor type transporter (ECF), homologous to the lhaSTA operon, has been found into a 13-gene putative operon and strongly overexpressed under iron-limitation condition. Moreover, the transcription of genes involved in resistance to oxidative stress (including catalase), virulence, transcriptional regulation, and hemin detoxification were also modified. These data provide some answers on the cellular response to the iron-limitation stress that is important for the opportunistic behavior of this pathogen.

My PhD project on the study of opportunistic factors in Staphylococcus lugdunensis aimed to better un- derstand how this commensal bacterium can be responsible for serious infections. The first part of our work was the construction of the ΔagrA and ΔRNAIII mutants of S. lugdunensis, encoding regulators potentially involved in virulence, to phenotypically characterize them and to identify the members of the regulons by global transcriptomic and proteomic analyzes. Our results have shown that AgrA is the major regulator of the Agr system in S. lugdunensis and that it controls the expression of genes allowing it to be more virulent, to adapt to environmental stresses (especially osmotic and oxidative stresses), to induce the formation of biofilm as well as the synthesis of carotenoid pigments. The second part of our work con- sisted in evaluating the impact of iron limitation, which represents a stress encountered by bacteria during infection, on the expression of the pathogenicity of S. lugdunensis. Phenotypic, transcriptomic and pro- teomic approaches were undertaken and the method for evaluating the pathogenicity of S. lugdunensis in a model of infection of Galleria mellonella larvae was developed. Our data revealed that iron deficiency in S. lugdunensis is a stress that promotes its ability to form biofilm while decreasing its resistance to oxidative stress as well as its virulence. Moreover, in response to this condition, S. lugdunensis is able to set up several mechanisms of iron acquisition, which probably provides it an advantage during infection and may partly explain the opportunistic behavior of this pathogen., Mon projet de thèse portant sur l’étude des facteurs d’opportunisme chez Staphylococcus lugdunensis avait pour but de mieux comprendre comment cette bactérie commensale peut être responsable d’in- fections graves. La première partie de nos travaux a consisté en la construction chez S. lugdunensis de mutants ΔagrA et ΔARNIII, codant des régulateurs potentiellement impliqués dans la virulence, afin de les caractériser phénotypiquement et d’identifier les membres des régulons par des analyses transcripto- mique et protéomique globales. Nos résultats ont mis en évidence que AgrA est le régulateur majeur du système Agr chez S. lugdunensis et qu’il contrôle l’expression de gènes lui permettant d’être plus virulent, de s’adapter aux stress environnementaux (notamment les stress osmotique et oxydatif), d’induire la formation de biofilm ainsi que la synthèse des pigments caroténoïdes. La seconde partie de nos travaux a consisté à évaluer l’impact de la limitation en fer, qui représente un stress rencontré par les bactéries pendant l’infection, sur l’expression de la pathogénicité de S. lugdunensis. Des approches phénotypique, transcriptomique et protéomique ont été entreprises et la méthode d’évaluation de la pathogénicité de S. lugdunensis en modèle d’infection de larves de Galleria mellonella a été mise au point. Nos données ont révélé que la carence en fer chez S. lugdunensis est un stress qui favorise sa capacité à former du biofilm tandis qu’il diminue sa résistance au stress oxydatif ainsi que sa virulence. De plus, en réponse à la condition de limitation en fer, S. lugdunensis est capable de mettre en place plusieurs mécanismes d’acquisition du fer, ce qui lui apporte vraisemblablement un avantage lors de l’infection et peut expliquer en partie le caractère opportuniste de ce pathogène.

Staphylococcus lugdunensis, originally identified in 1988, is a coagulase negative staphylococcus (CNS) that has become a significant human pathogen. It has been found as a source of skin and soft tissue infection, endocarditis, urogenital tract infection, joint infection, and meningeal infection. Rarely, it manifests as scrotal infections or complications. Correct identification of the bacterial organism and prompt treatment is crucial in these cases, as delayed intervention can lead to complications requiring orchiectomy. We describe a rare case of a young male who presented with scrotal pain and swelling and was found to have epididymo-orchitis with scrotal pyocele on imaging. He underwent scrotal exploration with incision and drainage and did not require an orchiectomy. Wound cultures grew S. lugdunensis, and the patient clinically improved after being treated with appropriate antibiotics. To our knowledge, this is the first reported case of scrotal abscess and epididymo-orchitis with pyocele formation caused by S. lugdunensis.

Case We describe the case of a 74-year-old man who developed severe hip pain several days after an intra-articular methylprednisolone injection to his right hip. Culture of the ipsilateral iliopsoas bursa revealed a Staphylococcus lugdunensis infection, which was successfully eradicated through irrigation and debridement as well as antibiotics. Conclusion Infection after hip injection is a known theoretical risk but is rarely reported in the literature. We present a case of septic bursitis after corticosteroid injection. Readers should be mindful that these complications do occur in clinical practice and portend significant morbidity.

Background Coronary artery embolism is an infrequent cause of type 2 myocardial infarction which can be due to arterial thromboembolism or septic embolism. While systemic embolization is one of the most acknowledged and threatened complications of infective endocarditis, coronary localization of the emboli causing acute myocardial infarction is exceedingly rare occurring in Case summary A 52-year-old man with a history of Bentall procedure and redo aortic valve replacement due to prosthetic degeneration (11 years prior to the current presentation) presented to the emergency department with high-grade fever and myalgias. Shortly after his arrival, he experienced typical chest pain and an electrocardiogram demonstrated signs of inferior ST-elevation myocardial infarction: coronary angiography showed a lesion of presumed embolic origin at the level of the mid-distal circumflex coronary artery which was treated with embolectomy. Transthoracic and transoesophageal echocardiography highlighted the presence of a periaortic abscess. The final diagnosis of infective endocarditis as the cause of septic coronary artery embolization was confirmed with a Positron Emission Tomography-Computed Tomography (PET-CT) exam and by the growth of Staphylococcus lugdunensis on repeated blood cultures. The patient underwent successful redo Bentall surgery the good outcome was confirmed at 1-month follow-up. Discussion Type 2 myocardial infarction caused by coronary embolism is a rare presentation of infective endocarditis and requires a high level of suspicion for its diagnosis. Prosthetic heart valves are a predisposing factor for infective endocarditis: aortic root abscess requires surgery as it rarely regresses with antibiotic therapy.