El Zein, Said

Abstract Background Chronic Q fever, caused by Coxiella burnetii, presents significant diagnostic and management challenges due to its variable presentation and high morbidity, especially among patients with underlying cardiac or vascular disease. In the United States, cases are rising, often without identifiable exposures, and diagnostic delays remain common. Methods We conducted a retrospective cohort study of chronic Q fever cases at the Mayo Clinic from 2007 to 2023. Patients with clinical evidence and a phase I IgG titer ≥1:1024 and/or positive PCR for C. burnetii were included. Data were abstracted from electronic health records, including demographics, exposures, clinical manifestations, diagnostics, treatments, and outcomes. Statistical analyses assessed factors influencing diagnostic delay and treatment response. Results We identified 33 patients with chronic Q fever (median age 56; 88% male). Median time to diagnosis was 99 days with 11.4 days between Infectious Diseases (ID) evaluation and diagnosis. Animal exposure was reported in 17 patients (52%), while eight (24%) had no identifiable exposure. Patients primarily presented with prosthetic valve endocarditis (n=14, 42%), or vascular graft infection (n=9, 27%). The majority were treated with doxycycline and hydroxychloroquine (n=25, 75%) and 14 patients (42%) required surgical intervention. Mortality attributable to chronic Q fever was 6% (n=2). Conclusions Chronic Q fever remains under-recognized, with substantial diagnostic delays prior to treatment. Cardiovascular infection predominates, and surgical intervention is often required despite prolonged antimicrobial therapy. Early specialist evaluation and standardized diagnostic pathways may improve outcomes.

Abstract Background The number of arthroplasty procedures and infection-related complications, including prosthetic joint infections (PJIs) and surgical site infections (SSIs), continues to rise. Although current guidelines recommend cefazolin or cefuroxime as the first-line perioperative prophylactic antibiotic, substitutions with non-cephalosporins remain common, especially among patients with reported β-lactam allergies. These substitutions may increase infection risk and healthcare costs. Evidence comparing outcomes across antibiotic classes remains variable. Methods We conducted a systematic review and meta-analysis of studies comparing single-agent cephalosporin versus single-agent non-cephalosporin prophylaxis in adults undergoing primary arthroplasty. Cochrane, Embase, Medline, Scopus, and Web of Science were searched from database inception through January 2025. Random-effect or fixed-effect models were used to estimate pooled odds ratios (OR) and 95% confidence intervals (CI). Subgroup analyses stratified results by cephalosporin type, study era, and risk of bias. Results Twenty-three studies (7 randomized controlled trials and 16 observational studies) were included, encompassing 191 527 arthroplasties in the cephalosporin arm and 20 058 in the non-cephalosporin arm. The odds of PJI were lower with cephalosporins (OR 0.59; 95% CI, .46–.75). No overall difference was observed for SSI (OR 0.70; 95% CI, .36–1.36), though post-2013 studies and the cefazolin subgroup demonstrated a significant protective effect. Randomized trial estimates were limited and heterogeneous and did not reach statistical significance. Certainty of evidence was graded as moderate. Conclusions Cephalosporins, particularly cefazolin or cefuroxime, remain the preferred prophylactic agents for primary arthroplasty. This quantitative synthesis reinforces their protective association against prosthetic joint infection and supports adherence to guideline-endorsed prophylaxis.

Abstract Background Although recent guidance recommends early surgical debridement for native joint septic arthritis (NJSA), supporting data, particularly on long-term outcomes, remains scarce. Methods We conducted a retrospective multicenter cohort study of adults (≥18 years) with NJSA who underwent surgery across Mayo Clinic campuses between 2012 and 2021. Clinical outcomes at 1 year were assessed using a 9-level Desirability of Outcome Ranking (DOOR) scale, incorporating survival, treatment failure (relapse, reinfection, readmission, or significant surgical events), and joint recovery. Time to surgery from hospital admission was analyzed both as a continuous variable and as categories: < 1, 1–2, or ≥3 days. Results Among 268 patients, 30% underwent surgery <1 day from admission, 47% in 1–2 days, and 24% in ≥3 days. At 1 year, 57% achieved full recovery without unfavorable events (DOOR score 1), while treatment failure occurred in 34%. In unadjusted analyses, longer surgical delay was significantly associated with higher (worse) DOOR scores (per IQR increase [from 0 to 2 days], OR: 1.5; 95% CI: 1.0–2.1; P = .026), increased 1-year mortality (HR: 1.7; 95% CI: 1.1–2.6; P = .019) and treatment failure (HR: 1.5; 95% CI: 1.1–2.0; P = .007). Even after adjusting for age and Charlson comorbidity index, the association between surgical delay and treatment failure remained significant (HR: 1.5; 95% CI, 1.1–2.0; P = .016). Conclusions The finding that delayed surgical intervention is associated with an increased risk of treatment failure reinforces current expert recommendations for timely surgical management in NJSA.

Background Identifying a microorganism in patients with native vertebral osteomyelitis presents diagnostic challenges. Microorganism identification through culture-based methods is constrained by prolonged processing times and sensitivity limitations. Despite the availability of molecular diagnostic techniques for identifying microorganisms in native vertebral osteomyelitis, there is considerable variability in reported sensitivity and specificity across studies, leading to uncertainty in their clinical utility. Questions/purposes What are the sensitivity, specificity, and diagnostic odds ratios for 16S broad-range PCR followed by Sanger sequencing (16S) and metagenomic next-generation sequencing (NGS) for detecting bacteria in native vertebral osteomyelitis? Methods On June 29, 2023, we searched Cochrane, Embase, Medline, and Scopus for results from January 1970 to June 2023. Included studies involved adult patients with suspected native vertebral osteomyelitis undergoing molecular diagnostics—16S bacterial broad-range PCR followed by Sanger sequencing and shotgun or targeted metagenomic NGS—for bacteria detection. Studies involving nonnative vertebral osteomyelitis and cases of brucellar, tubercular, or fungal etiology were excluded. The reference standard for the diagnosis of native vertebral osteomyelitis was a composite clinical- and investigator-defined native vertebral osteomyelitis diagnosis. Diagnostic performance was assessed using a bivariate random-effects model. Risk of bias and diagnostic applicability were evaluated using the revised Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. After a manual screening of 3403 studies, 10 studies (5 on 16S, 5 on NGS) were included in the present analysis, from which 391 patients were included from a total of 958 patients overall. Quality assessment via QUADAS-2 criteria showed moderate risk of bias and good applicability. Results 16S showed 78% (95% confidence interval [CI] 95% CI 31% to 96%) sensitivity and 94% (95% CI 73% to 99%) specificity, whereas NGS demonstrated 82% (95% CI 63% to 93%) sensitivity and 71% (95% CI 37% to 91%) specificity. In addition, the diagnostic ORs were 59 (95% CI 9 to 388) and 11 (95% CI 4 to 35) for 16S and NGS, respectively. Summary receiver operating characteristic curves showed high test performance for 16S (area under the curve for 16S 95% [95% CI 93% to 97%] and for NGS 89% [95% CI 86% to 92%]). Certainty in estimates was moderate because of sample size limitations. Conclusion This meta-analysis found moderate-to-high diagnostic performance of molecular methods on direct patient specimens for the diagnosis of native vertebral osteomyelitis. When used as a complementary test to microbiological analyses, a positive 16S result rules in the diagnosis of native vertebral osteomyelitis, while further studies are needed to understand the role of NGS in the diagnosis of native vertebral osteomyelitis. When available, these tests should be used in addition to conventional microbiology, especially in complex cases with extensively negative standard microbiological test results, to detect fastidious bacteria or to confirm the causative bacteria when their isolation and pathogenicity are unclear. A large sample size is needed in future research to understand the use of these techniques as standalone tests for diagnosis. Level of Evidence Level III, diagnostic study.

ABSTRACT A total of 1,925 Corynebacterium isolates were tested for antimicrobial susceptibility at the Mayo Clinic Microbiology laboratory (Rochester, Minnesota) from January 2012 to March 2023, with C. striatum (35.6%) and C. amycolatum (24.4%) identified as the predominant species. Species known to potentially carry diphtheria toxin were excluded. Common sources of isolation included skin and soft tissue (56.8%), bone and/or native joint synovial fluid (14.2%), urine (13.1%), sputum (6.1%), and blood (5.9%). For penicillin, susceptibility decreased from 47.5% (58 of 122) in 2012 to 20.6% (14 of 68) in 2023. Isolates also showed a decrease in susceptibility to erythromycin from 22.4% (26 of 116) in 2012 to 13.2% (9 of 68) in 2023. Susceptibility to trimethoprim-sulfamethoxazole averaged around 50% throughout the period. Notably, linezolid and vancomycin were universally effective in vitro against all species. The highest susceptibility rates among tested oral agents were to linezolid and doxycycline for non- C . striatum species. Daptomycin minimal inhibitory concentrations (MICs) of >256 µg/mL were observed for one C. amycolatum isolate, one C. tuberculostearicum isolate, and for seven C. striatum isolates, all from patients with prior daptomycin exposure. Daptomycin MICs of 2 µg/mL (nonsusceptible) were observed in one C. striatum isolate recovered from a daptomycin-naïve patient and in six C. jeikeium isolates, from both daptomycin-exposed and non-exposed patients. Significant variation in susceptibility profiles across different Corynebacterium species underscores the importance of performing antimicrobial susceptibility testing to guide effective treatment. Moreover, multidrug resistance observed in C. striatum poses substantial therapeutic challenges especially in patients requiring prolonged or chronic antibiotic suppression.

The incidence of culture-negative NVO (CN-NVO) cases is increasing, presenting significant diagnostic and therapeutic challenges due to the inability to isolate causative organisms with conventional microbiological methods. Factors influencing the diagnosis of CN-NVO include prior antimicrobial therapy, low pathogen burden, fastidious or intracellular organisms, technical issues, and non-infectious mimickers. Diagnosis often relies on imaging modalities like magnetic resonance imaging (MRI) and computed tomography (CT)-guided biopsy, though these methods can sometimes fail to yield positive microbiological results. Advanced diagnostic tools, such as polymerase chain reaction (PCR), metagenomic next-generation sequencing (mNGS), and cell-free DNA analysis, may be necessary to identify the pathogen. The causative pathogen cannot be isolated in some patients, among which an empirical antimicrobial therapy should be initiated. This narrative review discusses the management, monitoring, surgical indications, and outcomes for patients with CN-NVO.

Abstract Managing pelvic osteomyelitis (POM) in the setting of stage IV pressure injuries requires multidisciplinary evaluation as well as patient and caregiver engagement and is complicated by the lack of high-evidence data to guide best practices. In this review, we describe our approach to pressure injury and POM evaluation and management through multidisciplinary collaboration and highlight areas of future research that are necessary to enhance patient outcomes, reduce healthcare costs, and improve the quality of life of those affected by POM.

Abstract Managing pelvic osteomyelitis (POM) in the setting of stage IV pressure injuries requires multidisciplinary evaluation as well as patient and caregiver engagement and is complicated by the lack of high-evidence data to guide best practices. In this review, we describe our approach to pressure injury and POM evaluation and management through multidisciplinary collaboration and highlight areas of future research that are necessary to enhance patient outcomes, reduce healthcare costs, and improve the quality of life of those affected by POM.

Abstract We examined the effect of preoperative antibiotic exposure and duration on synovial fluid samples from patients with native joint septic arthritis of the hip/knee. While exposure before diagnostic arthrocentesis did not affect fluid parameters, increased duration was associated with a decreased total nucleated cell count, underscoring the complex antibiotic effects on synovial fluid parameters.