Cutibacterium acnes clonal complexes display various growth rates in blood culture vials used for diagnosing orthopedic device-related infections.

OBJECTIVES: Blood culture bottles (BCBs) are commonly used for the diagnosis of infections associated with orthopedic devices. Although Cutibacterium acnes is an important pathogen in orthopedics, relatively little is known about its growth characteristics in BCBs. This prompted us to analyze the influence of bacterial genotype and clinical significance on time-to-detection (TTD) in BCBs. METHODS: We reviewed 59 cases of orthopedic device-related infections in which at least one intraoperative specimen yielded a pure C. acnes culture from anaerobic BCBs (BD Bactec Lytic/10 Anaerobic/F; Lytic-Ana) and/or solid media. A strain was considered infectant if the same genotype was present in two or more intraoperative samples. From these cases, we isolated a total of 72 unique C. acnes strains belonging to four multilocus sequence type clonal complexes (CCs): CC18, CC28, CC36 and CC53. Growth rate and TTD in Lytic-Ana BCB were studied under experimental conditions (inoculation of standard inoculum) and in clinical samples (inoculation of periprosthetic tissue samples). RESULTS: Median TTD values were shorter for CC53 compared to other CCs under experimental conditions (69 vs. 103 h; p < 0.001) and from clinical specimens (70 vs. 200 h; p = 0.02). Infectant strains had a shorter median TTD compared to contaminant strains in a clinical situation, while the difference was not observed under experimental conditions. CONCLUSIONS: The detection dynamics of C. acnes in Lytic-Ana BCBs were associated with genotype. Thus, TTD not only reflects the bacterial load in clinical samples, but may also reflect the intrinsic properties of the clonal complex of C. acnes.

Measurement of Serum Anti-staphylococcal Antibodies Increases Positive Predictive Value of Preoperative Aspiration for Hip Prosthetic Joint Infection.

BACKGROUND: Preoperative synovial fluid culture is pivotal in the early diagnosis of prosthetic joint infection (PJI) but may yield false-positive and false-negative results. We evaluated the predictive value of synovial fluid culture results combined with the measurement of serum anti-staphylococcal antibodies (SASA). QUESTIONS/PURPOSES: (1) For hip and knee PJI, does combining positive SASA results with preoperative synovial culture results improve the positive predictive value (PPV) of preoperative synovial fluid culture alone? (2) Does combining preoperative synovial fluid culture results with a positive cell count and differential result increase the PPV of preoperative synovial fluid culture alone? (3) What proportion of isolated organisms exhibit concordance in antibiotic susceptibility: preoperative aspiration versus intraoperative isolates? METHODS: A prospective study was conducted at two French reference centers that manage bone and joint infections and included 481 adult patients who had a revision or resection arthroplasty between June 25, 2012 and June 23, 2014. Exclusion criteria including no serum sample available for immunoassay, the lack of microbiological documentation, and the absence of preoperative aspiration reduced the patient number to 353. Seven patients with an undetermined SASA result were excluded from the analysis. We also excluded patients with PJI involving more than one Staphylococcus species (polystaphylococcal infection) and those in whom more than one Staphylococcus species was recovered from the preoperative synovial fluid culture (polystaphylococcal synovial fluid culture). In total, 340 patients were included in the analysis (no infection, 67% [226 of 340]; staphylococcal infection, 21% [71 of 340]; other infection, 13% [43 of 340]). The preoperative synovial fluid analysis included a cell count and differential and bacterial culture. SASAs were measured using a multiplex immunoassay. The diagnosis of PJI was determined using the Infectious Diseases Society of America (IDSA) criteria [] and intraoperative tissue culture at the time of revision surgery was used as the gold standard (at least one positive intraoperative sample for a "virulent" organism (such as S. aureus) or two positive samples for a "non-virulent" (for example S. epidermidis). RESULTS: SASA increased the PPV compared with synovial fluid culture alone (92% [95% CI 82 to 97] versus 79% [95% CI 68 to 87]; p = 0.04); when stratified by site, an increase in PPV was seen in hip infections (100% [95% CI 89 to 100] versus 77% [95% CI 63 to 88]; p = 0.01) but not in knee infections (84% [95% CI 66 to 95] versus 80% [95% CI 64 to 91]; p = 0.75). A positive cell count and differential result increased the PPV of staphylococcal synovial fluid cultures compared with synovial fluid culture alone (86% [95% CI 70 to 95] versus 79% [95% CI 68 to 87]; p = 0.36); when stratified by site, no difference in hip and knee infections was observed (86% [95% CI 67 to 96] versus 77% [95% CI 63 to 88]; p = 0.42) and 86% [95% CI 70 to 95] versus 80% [95% CI 64 to 91]; p = 0.74). CONCLUSION: SASA measurement improves the predictive value of synovial fluid cultures of the hip for all staphylococcal organisms, including coagulase-negative staphylococci, but the PPV of SASA plus synovial fluid culture it is not superior to the PPV of synovial fluid cell count/differential plus synovial culture for the knee. LEVEL OF EVIDENCE: Level III, diagnostic study.

Growth detection of Cutibacterium acnes from orthopaedic implant-associated infections in anaerobic bottles from BACTEC and BacT/ALERT blood culture systems and comparison with conventional culture media.

Cutibacterium acnes is a major etiologic agent of orthopaedic implant-associated infections (IAIs) and requires up to 14 days of incubation in an anaerobic atmosphere for growth detection. As blood culture (BC) systems are increasingly being used to monitor the growth of IAI specimens, we compared different BC media for growth detection of C. acnes. Non-duplicate C. acnes isolates (n = 99) obtained from sonicate-fluid cultures of orthopaedic IAIs from Slovenia (n = 54), conventional tissue samples of monomicrobial orthopaedic IAIs from France (n = 43) and two reference strains were inoculated to anaerobic BC bottles of two major BC systems and 3 conventional culture media types (thioglycolate broth, Schaedler and chocolate agar). Growth and time-to-detection (TTD) were recorded. Only Lytic (BACTEC) and SN (BacT/ALERT) bottles consistently detected growth of C. acnes within 14 days with 94% (n = 93) and 92% (n = 91) detection rates, respectively (p = 0.79). Lytic was superior to Plus BACTEC medium (p < 0.001), while SN was superior to all other BacT/ALERT media (p < 0.001). Mean TTD was 128 ± 43 h (61-336 h) for Lytic and 158 ± 65 h (77-336 h) for SN medium. Among the conventional media, 99% (n = 98) of the isolates grew on Schaedler agar, 96% (n = 95) in thioglycolate broth and 74% (n = 73) on chocolate agar. Inconsistent growth of C. acnes in different BC media can critically influence the detection of this major IAI pathogen. Only Lytic (BACTEC) and SN (BacT/ALERT) BC media types were consistently able to detect C. acnes within 14 days of incubation. However, visible growth was observed faster in thioglycolate broth and Schaedler agar media.

Molecular Typing of Multiple Isolates Is Essential to Diagnose Cutibacterium acnes Orthopedic Device-related Infection.

Cutibacterium acnes orthopedic device-related infections (ODRIs) range from obvious infections to solely culture-based diagnoses. Multilocus sequence typing of multiple isolates from the same procedure revealed that most cases with normal C-reactive protein levels that were classified as C. acnes ODRI would be considered contaminations when accounting for genotypic data.

Monomicrobial bone and joint infection due to Corynebacterium striatum: literature review and amoxicillin-rifampin combination as treatment perspective.

Corynebacterium striatum is a ubiquitous colonizer of human skin and mucous membranes. It is increasingly involved in infections, especially with prosthetic devices or in immunocompromised individuals. Microbiological diagnosis is challenging and bacterial resistance is a major concern. We performed a retrospective study of monomicrobial bone and joint infections (BJI) due to C. striatum in two referral centers from April 2012 to July 2017. We collected the patients' clinical and microbiological characteristics and outcomes. We also performed a literature review of BJI due to C. striatum. We identified 12 cases (nine prosthetic joint infections, one osteosynthetic device infection, one non-union, and one arthritis) in 11 patients, five of which were immunocompromised. Microbiological diagnosis was performed with prolonged culture media. Ten out of 12 strains were susceptible to aminopenicillin, a drug class not recommended for testing by the EUCAST/CASFM guidelines, and 8/12 patients were treated with amoxicillin-rifampicin. The cure rate was 8/12, after a median follow-up period of 487.5 days (IQR 140.3-1348.5). Twelve cases of BJI due to C. striatum were previously reported. Among them, 5/12 patients were immunocompromised, 3/12 cases were acute BJI, and 2/12 were device-related infections. The diagnosis was performed by PCR in one case, and 10/12 patients were treated with glycolipopeptides, with a cure rate of 11/12. We report the largest cohort of monomicrobial BJI with C. striatum. Determination of aminopenicillin susceptibility is essential since it is frequently active in our experience, even in BJI. The cure rate of this infection seems high.

In-Host Adaptation of Salmonella enterica Serotype Dublin during Prosthetic Hip Joint Infection.

Genome degradation has been central to the adaptation of Salmonella enterica serotypes to their hosts throughout evolution. We witnessed the patho-adaptation of a strain of Salmonella Dublin (a cattle-adapted serotype) to a human host during the course of a recurrent prosthetic hip joint infection evolving over several years.

Ruminococcus gnavus total hip arthroplasty infection in a 62-year-old man with ulcerative colitis.

We report the case of a total hip arthroplasty infection caused by Ruminococcus gnavus in a 62-year-old man with ulcerative colitis. The bacterium was perfectly identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry.

Single-stage revision for total shoulder arthroplasty infection. Results at a minimum 2 years follow-up.

INTRODUCTION: Similar to the management of periprosthetic joint infections of the lower limb, one-stage revision in total shoulder arthroplasty (TSA) infections is an option that has been highlighted in scientific publications since the early 2010s. However, there are only a few studies which validate this treatment and determine its scope of application in relation to two-stage treatment. HYPOTHESIS: Single-stage revision for infected TSA is a reliable treatment allowing good infection control and satisfactory functional results. METHODS: This single-center retrospective series of 34 consecutive patients operated on between 2014 and 2020 for a one-stage prosthetic revision was evaluated at a minimum of 2 years of follow-up. All of the patients included underwent revision shoulder arthroplasty during this period with the diagnosis of infection confirmed by microbiological analysis of surgical samples. Patients who did not benefit from a bipolar revision were excluded. All patients were followed at least 2 years after the intervention. Clinically suspected recurrence of infection was confirmed by a periprosthetic sample under radiographic guidance. Functional clinical outcomes as well as mechanical complications were also reported. RESULTS: The average follow-up was 40.4 months (24-102±21.6). A septic recurrence was observed in three patients (8.8%). A mechanical complication was present in four patients (14.7%), and three (11.8%) required at least one surgical revision. The mean Constant-Murley score at the last follow-up was 49 (42-57±21.83). DISCUSSION: Single-stage revision for shoulder periprosthetic joint infection results in a success rate of 91.2% with satisfactory functional results after more than 2 years of follow-up. LEVEL OF EVIDENCE: IV; retrospective study.

A prospective multicentre evaluation of BioFire® Joint Infection Panel for the rapid microbiological documentation of acute arthritis.

OBJECTIVES: To assess the performance of the rapid syndromic BioFire® Joint Infection Panel (BF-JIP) to detect bacterial and fungal pathogens, as well as antibiotic resistance genes, directly in synovial fluid specimens collected from patients with acute arthritis. METHODS: The study was conducted in six French bacteriological laboratories. To assess the performances of BF-JIP, results were compared with those of synovial fluid 14-day culture and, in case of discrepancy, with those of complementary molecular methods and intraoperative samples. A total of 308 synovial fluid specimens were tested after collection from 308 adults and children presenting with clinical and biological suspicion of acute arthritis; patients presenting with acute periprosthetic joint infection were included according to the European Bone and Joint Infection Society 2021 criteria. RESULTS: Only one specimen failed (no result). On the basis of the consolidated data, the BF-JIP was concordant with the 14-day culture in 280 (91.2%) of the 307 specimens finally included in the study. The positive percentage agreement was 84.9% (95% CI, 78.8-89.8%) and the negative percentage agreement was 100% (95% CI, 97.2-100%). The positive predictive value was extremely high (100%; 95% CI, 97.6-100%), whereas the negative predictive value was lower (82.6%; 95% CI, 75.7-88.2%), partially explained by the missing target species in the panel. DISCUSSION: The BF-JIP showed high performances to detect pathogens involved in acute arthritis.

In Vivo Emergence of Dual Resistance to Rifampin and Levofloxacin in Osteoarticular Cutibacterium avidum.

Cutibacterium avidum is an emerging causative agent of orthopedic device-related infections (ODRIs). There are no guidelines for the antimicrobial treatment of C. avidum ODRI, but oral rifampin is frequently used in combination with a fluoroquinolone following intravenous antibiotics. We describe the in vivo emergence of combined resistance to rifampin and levofloxacin in a C. avidum strain isolated from a patient with early-onset ODRI treated with debridement, antibiotic treatment, and implant retention (DAIR) using rifampin combined with levofloxacin as the oral treatment. Whole-genome sequencing of C. avidum isolates before and after antibiotic exposure confirmed strain identity and identified new mutations in rpoB and gyrA, leading to amino acid substitutions previously reported to be associated with resistance to rifampin (S446P) and fluoroquinolones (S101L), respectively, in other microbial agents, in the posttherapy isolate. Aside from the molecular insights reported here, this study highlights potential limitations of the combination of oral rifampin and levofloxacin in patients undergoing a DAIR procedure for C. avidum ODRI and the potential need to evaluate specific optimal therapy for emerging ODRI pathogens. IMPORTANCE In this study, we report for the first time the in vivo emergence of dual resistance to levofloxacin and rifampin in C. avidum isolated from a patient who received both antibiotics orally in the setting of a salvage debridement and implant retention of an ODRI. Aside from the molecular insights reported here, this study highlights potential limitations of the combination of oral rifampin and levofloxacin in patients undergoing these surgical procedures and the potential need to evaluate specific optimal therapy for emerging ODRI pathogens.

Non-Legionella pneumophila serogroup 1 pneumonia: Diagnosis of a nosocomial legionellosis with the Biofire Pneumonia plus panel.

We report a nosocomial case of Legionella pneumophila pneumonia caused by a serogroup 10 strain diagnosed with the Biofire® Pneumonia plus panel. Molecular investigations of the environment of the patient allowed us to identify the source of contamination.

Clinical Cutaneous Features of Patients Infected With SARS-CoV-2 Hospitalized for Pneumonia: A Cross-sectional Study.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of a current pandemic worldwide. This virus can reach all organs and disturbs the immune system, leading to a cytokine storm in severe forms. We aimed to report cutaneous features among coronavirus disease 2019 (COVID-19) hospitalized patients. METHODS: We performed a cross-sectional study on 1 given day among all patients hospitalized in acute care for COVID-19 and included all patients with cutaneous features. Follow-up 48 hours later was obtained. RESULTS: Among 59 adult patients hospitalized on the day of the study in an infectious diseases ward for SARS-CoV-2 infection who were confirmed by molecular assay and/or radiological findings (computed tomography scan), 40 were included. Several cutaneous manifestations were found: macular exanthema (80%), face edema (32%), livedo (13%), urticarial rash (8%), purpura (5%), oral lichenoid lesions (33%), and conjunctivitis (18%). Cutaneous biopsy was performed in 17 patients. Histological findings showed mast cell hyperplasia (100%), superficial perivascular infiltrate of lymphocytes (94%), and superficial edema (47%) consistent with capillary leak. CONCLUSIONS: Various dermatological signs can be encountered during COVID-19. A macular rash was the most frequent. All cutaneous features could be related to a vascular leak process.

Epidemiology of extended-spectrum beta-lactamase-producing Enterobacteriaceae in an intensive care unit with no single rooms.

BACKGROUND: The transmission of extended-spectrum beta-lactamase-producing enterobacteriaceae (ESBL) is prevented by additional contact precautions, mainly relying on isolation in a single room and hand hygiene. Contact isolation cannot be achieved in our 12-bed ICU, which has only double rooms. We report the epidemiology of ESBL imported, acquired and transmitted in an ICU with no single rooms. METHODS: We prospectively conducted an observational and non-interventional study in a French 12-bed ICU. Inclusion criteria were patients >18 years of age treated by at least two successive nursing teams. Patient characteristics at admission and clinical data during hospital stay were collected prospectively. ESBL carriage was monitored using rectal swabs collected at admission and once weekly during the ICU stay. Potential cross-transmission was studied (1) by identifying index patients defined as possible ESBL sources for transmission, (2) by classifying each ESBL strain according to the cefotaximase München (CTXM) 1 and 9 groups and (3) by gene sequencing for remaining cases of possible transmission. RESULTS: From June 2014 to April 2015, of 550 patients admitted to the ICU, 470 met the inclusion criteria and 221 had at least two rectal swabs. The rate of ESBL colonization, mainly by Escherichia coli, at admission was 13.2%. The incidence of ESBL acquisition, mainly with E. coli too, was 4.1%. Mortality did not differ between ESBL carriers and non-carriers. In univariate analysis, ESBL acquisition was associated with male gender, SAPS II, SOFA, chronic kidney disease at admission, duration of mechanical ventilation, need for catecholamine and the ICU LOS. In multivariate analysis, SAPS II at admission was the only risk factor for ESBL acquisition. We confirmed cross-transmission, emanating from the same index patient, in two of the nine patients with ESBL acquisition (0.8%, 2/221). No case of cross-transmission in the same double room was observed. DISCUSSION AND CONCLUSION: Prevalence of ESBL colonization in our ICU was 13.2%. Despite the absence single rooms, the incidence of ESBL acquisition was 4.1% and cross-transmission was proven in only two cases, resulting from the same index patient who was not hospitalized in the same double room.

Pasteurella infection after muraenidae bite in an HIV infected patient.

We report a case of Pasteurella dagmatis wound infection in an immunocompromised HIV infected patient after bite by a marine carnivore in Caribbean Sea (Dominican Republic), presumably a muraenidae. Identification of the Pasteurella species from wound sampling was obtained twice by mass spectrometry and confirmed by 16S RNA sequencing.

Outbreak of multidrug-resistant Klebsiella pneumoniae carrying qnrB1 and blaCTX-M15 in a French intensive care unit.

BACKGROUND: The prevalence of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae is increasing globally and is a major clinical concern. Between June 2008 and September 2009, 4% of patients in an intensive care unit (ICU) were found to be colonized or infected by strains of Klebsiella pneumoniae multiresistant to ceftazidime, ciprofloxacin, and tobramycin; an investigation was initiated and isolates were characterized by molecular typing and resistance patterns. METHODS: Antibiotic susceptibilities were determined by Vitek2®, Etest®, and agar dilution. Gene encoding beta-lactamases and plasmid-mediated quinolone resistance PMQR determinants (qnr, aac(6')-Ib) were characterized by PCR, sequencing, and transfer assays. DiversiLab® fingerprints were used to study the relatedness of isolates. RESULTS: Fourteen isolates co-expressing blaCTX-M15, qnrB1, and aac(6')-Ib-cr were identified. Genotypic analysis of these isolates identified 12 clonally related strains recovered from 10 patients. The increased prevalence of blaCTX-M15-qnrB1-aac(6')-Ib-cr-producing K. pneumoniae coincided with the presence in the ICU of a patient originally from Nigeria. This patient was infected by a strain not clonally related to the others but harbouring qnrB1 and aac(6')-Ib-cr genes, a finding not hitherto observed in France. We suspected transmission of resistance plasmids followed by rapid dissemination of the multiresistant K. pneumoniae clone by cross-transmission. CONCLUSION: This study highlights the importance of microbiological screening for multidrug-resistant strains in ICUs, particularly among patients from regions in which multidrug-resistant bacteria are known to exist.