Patel, Robin

SUMMARY Prosthetic joint infection (PJI) is a tremendous burden for individual patients as well as the global health care industry. While a small minority of joint arthroplasties will become infected, appropriate recognition and management are critical to preserve or restore adequate function and prevent excess morbidity. In this review, we describe the reported risk factors for and clinical manifestations of PJI. We discuss the pathogenesis of PJI and the numerous microorganisms that can cause this devastating infection. The recently proposed consensus definitions of PJI and approaches to accurate diagnosis are reviewed in detail. An overview of the treatment and prevention of this challenging condition is provided.

ABSTRACT We describe the first reported case of Ureaplasma parvum prosthetic joint infection (PJI) detected by PCR. Ureaplasma species do not possess a cell wall and are usually associated with colonization and infection of mucosal surfaces (not prosthetic material). U. parvum is a relatively new species name for certain serovars of Ureaplasma urealyticum , and PCR is useful for species determination. Our patient presented with late infection of his right total knee arthroplasty. Intraoperative fluid and tissue cultures and pre- and postoperative synovial fluid cultures were all negative. To discern the pathogen, we employed PCR coupled with electrospray ionization mass spectrometry (PCR/ESI-MS). Our patient's failure to respond to empirical antimicrobial treatment and our previous experience with PCR/ESI-MS in culture-negative cases of infection prompted us to use this approach over other diagnostic modalities. PCR/ESI-MS detected U. parvum in all samples. U. parvum -specific PCR testing was performed on all synovial fluid samples to confirm the U. parvum detection.

We assessed the in vitro activity of Manuka honey against biofilm bacteria in combination with antibiotics and visualized the effect of Manuka honey on bacterial biofilms using scanning electron microscopy. The fractional biofilm eradication concentration ( ∑ FBEC ) index for vancomycin plus Manuka honey against S. aureus IDRL-4284 biofilms was 0.34, indicating a synergistic interaction. The ∑ FBEC index for gentamicin plus Manuka honey against P. aeruginosa PAO1 biofilms was 0.78–0.82, indicating an additive interaction. Scanning electron microscopy of S. aureus IDRL-4284 and P. aeruginosa PAO1 biofilms exposed to Manuka honey and artificial honey containing the same sugar composition as Manuka honey showed that the former had more pronounced effects than the latter on both S. aureus and P. aeruginosa biofilms. Visualized effects included distorted cell morphologies for both bacteria and a decrease in P. aeruginosa extracellular matrix. In conclusion, Manuka honey has a synergistic interaction with vancomycin against S. aureus biofilms and an additive interaction with gentamicin against P. aeruginosa biofilms.

ABSTRACTA 75-year-old man was diagnosed with probableCampylobacter jejuniprosthetic knee infection after a diarrheal illness. Joint aspirate and operative cultures were negative, but PCR of prosthesis sonicate fluid was positive, as was stool culture. Nineteen additional cases ofCampylobacterprosthetic joint infection reported in the literature are reviewed.

ABSTRACT We compared PCR-electrospray ionization mass spectrometry (PCR-ESI/MS) to culture using sonicate fluid from 431 subjects with explanted knee ( n = 270) or hip ( n = 161) prostheses. Of these, 152 and 279 subjects had prosthetic joint infection (PJI) and aseptic failure, respectively. The sensitivities for detecting PJI were 77.6% for PCR-ESI/MS and 69.7% for culture ( P = 0.0105). The specificities were 93.5 and 99.3%, respectively ( P = 0.0002).

ABSTRACT We assessed the performance of a duplex real-time PCR assay for bla KPC and bla NDM performed directly (D-PCR) on perianal and perirectal swabs and stool. Spiked specimens and 126 clinical surveillance swabs (comprising a sensitivity panel of 46 perirectal double swabs previously determined to be culture positive for bla KPC -PCR-positive Enterobacteriaceae and a specificity panel of 80 perianal swabs from patients at risk of carbapenemase-producing Enterobacteriaceae [CPE] colonization) were studied. For the surveillance swabs, D-PCR was compared to PCR after broth enrichment (BE-PCR) and two culture-based methods: the HardyCHROM ESBL agar (HC-A) and the CDC screening (CDC-A) methods. PCR was performed on morphologically distinct colonies that were isolated by culture. All of the initial PCR testing was done without extraction using a simple lysis procedure. The analytical sensitivities of D-PCR for bla KPC were 9 CFU/μl (for swabs) and 90 CFU/μl (for stool), and for bla NDM , it was 1.9 CFU/μl (for both swabs and stool). In the clinical sensitivity panel, D-PCR and BE-PCR were initially positive for bla KPC in 41/46 (89.1%) and 43/46 (93.5%) swabs, respectively. The swabs that were initially negative by D-PCR ( n = 5) and BE-PCR ( n = 3) were visibly stool soiled; all swabs were bla KPC positive upon repeat testing after lysate extraction. The CDC-A and HC-A yielded bla KPC -positive Enterobacteriaceae from 36/46 (78.3%) and 35/46 (76.1%) swabs, respectively (sensitivities of D-PCR/BE-PCR postextraction of soiled specimens versus HC-A, P = 0.0009, and versus CDC-A, P = 0.0016). All swabs in the specificity panel were negative for CPE by all four methods. D-PCR allows for the timely detection of bla KPC and bla NDM carriage with excellent sensitivity when specimens visibly soiled with stool undergo preparatory extraction.

Abstract The critical role of the microbiology laboratory in infectious disease diagnosis calls for a close, positive working relationship between the physician and the microbiologists who provide enormous value to the health care team. This document, developed by both laboratory and clinical experts, provides information on which tests are valuable and in which contexts, and on tests that add little or no value for diagnostic decisions. Sections are divided into anatomic systems, including Bloodstream Infections and Infections of the Cardiovascular System, Central Nervous System Infections, Ocular Infections, Soft Tissue Infections of the Head and Neck, Upper Respiratory Infections, Lower Respiratory Tract infections, Infections of the Gastrointestinal Tract, Intraabdominal Infections, Bone and Joint Infections, Urinary Tract Infections, Genital Infections, and Skin and Soft Tissue Infections; or into etiologic agent groups, including Tickborne Infections, Viral Syndromes, and Blood and Tissue Parasite Infections. Each section contains introductory concepts, a summary of key points, and detailed tables that list suspected agents; the most reliable tests to order; the samples (and volumes) to collect in order of preference; specimen transport devices, procedures, times, and temperatures; and detailed notes on specific issues regarding the test methods, such as when tests are likely to require a specialized laboratory or have prolonged turnaround times. There is redundancy among the tables and sections, as many agents and assay choices overlap. The document is intended to serve as a reference to guide physicians in choosing tests that will aid them to diagnose infectious diseases in their patients.

We previously developed and validated a vortexing-sonication technique for detection of biofilm bacteria on the surface of explanted prosthetic joints. Herein, we evaluated this technique for diagnosis of infected breast tissue expanders and used it to assess colonization of breast tissue expanders. From April 2008 to December 2011, we studied 328 breast tissue expanders at Mayo Clinic, Rochester, MN, USA. Of seven clinically infected breast tissue expanders, six (85.7%) had positive cultures, one of which grewPropionibacteriumspecies. Fifty-two of 321 breast tissue expanders (16.2%, 95% CI, 12.3–20.7%) without clinical evidence of infection also had positive cultures, 45 growingPropionibacteriumspecies and ten coagulase-negative staphylococci. While vortexing-sonication can detect clinically infected breast tissue expanders, 16 percent of breast tissue expanders appear to be asymptomatically colonized with normal skin flora, most commonly,Propionibacteriumspecies.