Faculty Bibliography

BACKGROUND:Periprosthetic joint infection (PJI) remains one of the most challenging complications after total joint arthroplasty (TJA). While conventional culture remains the standard for identification of causative pathogens in PJI, rapid identification techniques such as polymerase chain reaction (PCR) are becoming increasingly popular, with little comparative data. METHODS:A retrospective review was performed on a database of consecutive patients who underwent workup for PJI at a tertiary referral center from January 1, 2023, to May 31, 2025. Patients who underwent both standard synovial fluid culture and a PCR panel on the same day were included. Synovial fluid culture was used as the reference standard, and test result concordance and turnaround time were assessed. RESULTS:Results from the PCR panel showed strong agreement with synovial fluid culture in the 225 cases analyzed, with 88% culture-positive agreement. The PCR false negatives were due to organisms not included in the PCR panel (n = six), a false-positive culture from contamination (n = one), and a patient who had a PJI due to Candida parapsilosis (n = two). When only considering true positives with organisms included in the panel, the PCR displayed a 97.1% culture-positive agreement. The panel also detected organisms in eight culture-negative cases (94.7% culture-negative agreement). Those cases each met the 2018 International Consensus Meeting definition of PJI, were treated as PJIs, and their negative culture results were hypothesized to be due to antibiotic use before culture. The panel's turnaround time (TAT) (median 8.4 hours) is significantly faster than both culture-positive (P < 0.001) (69.2 hours) and culture-negative (P < 0.001) (139.5 hours) results from synovial fluid culture. CONCLUSIONS:The high concordance between the panel and conventional culture techniques suggests that PCR may be added as an adjunctive diagnostic tool for PJI workup after TJA. Our results also suggest that PCR may be more accurate than fluid culture in patients who have current antibiotic usage. The PCR's advantage of rapid TAT is particularly helpful in the timely optimization of antibiotic therapy.

Rapid molecular assays guiding treatment of methicillin-resistant Staphylococcus aureus (MRSA) detect SCCmec (Xpert) or the SCCmec-orfX junction (BCID2). Sequence variation in this region can disrupt primer binding, yielding false-negative results. Investigation of a missed bloodstream infection linked escape to a CRISPR-Cas-associated SCCmec variant, leading to identification of 64 variants from 45 patients-2% of 2,432 screened. Misdiagnosis was restricted to clonal complex 5, a hospital-associated lineage; 11 of 40 SCCmec/junctions evaded detection by BCID2 or Xpert. Variants had mecA instability and circulated in healthcare settings. Our findings reveal a unique escape mechanism and underscore a threat to diagnostic accuracy.

Two unvaccinated infants residing in the same borough of New York, New York, USA, had Haemophilus influenzae type b meningitis develop 1 year apart. Whole-genome sequencing and phylogenetic analysis revealed the isolates shared a previously undescribed multilocus sequence type and were more closely related to each other than to other sequenced strains.

Syphilis screening during pregnancy is essential to prevent congenital syphilis, yet diagnostic challenges arise when clinical presentation, serologic results, and pathologic examination are discordant. We report the case of a 39-year-old pregnant patient with a reactive enzyme immunoassay (EIA) at delivery, despite prior nonreactive syphilis serologies and a negative confirmatory test postpartum. Placental examination revealed multiple intervillous abscesses and chronic villitis, raising concern for congenital syphilis. However, immunohistochemistry (IHC) for Treponema pallidum yielded conflicting results across laboratories. Despite the lack of confirmed maternal infection, the neonate underwent a full congenital syphilis evaluation and received penicillin treatment. This case highlights the complexities of interpreting isolated positive treponemal tests, the limitations of placental pathology in syphilis diagnosis, and the need for standardized management algorithms to prevent misclassification, overtreatment, and undue emotional and healthcare burden. Interdisciplinary communication and rapid confirmatory testing are critical to optimizing maternal and neonatal outcomes.

Inappropriate ordering practices, either under or over ordering of diagnostic tests, are recognized problems with possible negative downstream consequences. As the menu of clinical tests, especially molecular tests grows, it is becoming increasingly important to provide guidance to providers on the appropriate utilization. Diagnostic stewardship programs have been established at many institutions to help direct the appropriate utilization of laboratory testing to ultimately guide patient management and treatment decisions. Many molecular tests have now received Clinical Laboratory Improvement Amendments (CLIA)-waived status for use in a point-of-care (POC) setting; however, parallel diagnostic stewardship programs have not been established to help guide providers on how best to use these tests. In this article, we will discuss the available molecular POC tests and opportunities and challenges for establishing diagnostic stewardship programs for molecular testing performed in the POC setting.

We performed a retrospective survey of non-Candida albicans candidemia in patients with cancer, including those with solid tumors and those with hematological malignancies as well as transplants patients both, solid-organ transplant recipients and hematopoietic stem cell transplant recipients. The study was performed at two healthcare centers in New York City and covered the years 2018-2022. A total of 292 patients (318 isolates) were included in the study. In order of frequency, C. glabrata (38%) was the most common species recovered, followed by C. parapsilosis (19.2%), C. tropicalis (12.6%), C. krusei (10.7%), C. lusitaniae (5.7%), and C. guilliermondii (4.4%). Micafungin was the most common antifungal treatment and 18.5% of patients were on antifungal prophylaxis. The 30-day crude mortality was 40%. 4.5% of patients had more than one non-albicans species detected. In conclusion, this study represents one of the largest surveys of non-albicans species in cancer and transplant patients and provides data on the current epidemiology of these Candida species in this patient population.

Novel viral load monitoring strategies are needed to help individuals maintain an undetectable viral load (UVL). In 2018, U.S. MSM living with HIV with a past detectable VL received a dried blood spot (DBS) kit at baseline and 3-month follow-up and returned specimens to a research laboratory. Of 56 consenting participants, 91% returned specimens at baseline and 77% at 3-month follow-up; 74% who returned two specimens had UVL at both time points. At-home DBS collection and longitudinal VL monitoring is feasible among U.S. MSM with fluctuating viral load. This complementary approach to clinical care could improve viral suppression maintenance.

INTRODUCTION/BACKGROUND:Eikenella corrodens is a small, nonmotile Gram-negative rod that is part of the normal flora in the mouth, upper respiratory, gastrointestinal, and genitourinary tracts. It is classically found in human bite (fist to mouth) infections but is also seen in respiratory tract and head and neck infections. METHODS:We describe three cases of E. corrodens causing head and neck infections in children seen in our institution between 2013 and 2019. We also reviewed the available literature on pediatric head and neck infections caused by E. corrodens. RESULTS:All 3 children recovered and fit the trends identified in the 58 patients published in the literature from 1976 to 2019. CONCLUSIONS:E. corrodens is responsible for a range of head and neck infections in pediatric patients. It is a not infrequent cause of head and neck infections in children and should be considered when selecting presumptive antibiotic therapy.