Despite known low sensitivity, culture of periprosthetic tissue specimens on agars and in broths is routine. Culture of periprosthetic tissue samples in blood culture bottles (BCBs) is potentially more convenient, but it has been evaluated in a limited way and has not been widely adopted. The aim of this study was to compare the sensitivity and specificity of inoculation of periprosthetic tissue specimens into blood culture bottles with standard agar and thioglycolate broth culture, applying Bayesian latent class modeling (LCM) in addition to applying the Infectious Diseases Society of America (IDSA) criteria for prosthetic joint infection. This prospective cohort study was conducted over a 9-month period (August 2013 to April 2014) at the Mayo Clinic, Rochester, MN, and included all consecutive patients undergoing revision arthroplasty. Overall, 369 subjects were studied; 117 (32%) met IDSA criteria for prosthetic joint infection, and 82% had late chronic infection. Applying LCM, inoculation of tissues into BCBs was associated with a 47% improvement in sensitivity compared to the sensitivity of conventional agar and broth cultures (92.1 versus 62.6%, respectively); this magnitude of change was similar when IDSA criteria were applied (60.7 versus 44.4%, respectively; P = 0.003). The time to microorganism detection was shorter with BCBs than with standard media (P < 0.0001), with aerobic and anaerobic BCBs yielding positive results within a median of 21 and 23 h, respectively. Results of our study demonstrate that the semiautomated method of periprosthetic tissue culture in blood culture bottles is more sensitive than and as specific as agar and thioglycolate broth cultures and yields results faster.

Recent studies have demonstrated the utility of blood culture methods over standard agar plate and broth methods for the isolation of microorganisms from synovial fluid (1-6). Two of those studies evaluated older versions of the BACTEC blood culture system (Becton Dickinson Diagnostic Instrument Systems, Sparks, Md.) (2, 5, 6). We are unaware of similar evaluations for more recent medium formulations and instrument upgrades for the BACTEC system. The objective of the present study was to evaluate the utility of culture with the BACTEC Peds Plus/F Bottle and the BACTEC 9240 blood culture system for the detection of microorganisms in synovial fluid specimens from patients suspected of having septic arthritis. We used the Peds Plus/F bottle because in our laboratory the quantity of synovial fluid available for culture is frequently in the range of 0.5 to 3.0 ml. This is an accepted specimen inoculum size for the BACTEC Peds Plus/F bottle. MATERIALS AND METHODSAll synovial fluid specimens were collected from patients at the Mayo Medical Center in Rochester, Minn., who were suspected of having septic arthritis. Specimens that were from patients who declined use of their specimens and medical histories for evaluation (Minnesota Statute 144.335) or that contained an inadequate volume were excluded from the study. The Mayo Medical Center consists of two large teaching hospitals (combined number of beds, Ϸ1,800) and a large subspecialty clinic.Synovial fluid was collected with a sterile syringe, and the sample was transported to the clinical microbiology laboratory within a 2-h period. After receipt in the laboratory, an aliquot of synovial fluid was inoculated directly onto 5% sheep blood agar and chocolate agar, which were incubated at 35°C with 5 to 7% CO 2 for 2 days. In addition, approximately 0.25 ml was inoculated into thioglycolate broth, which was incubated at 35°C with 5 to 7% CO 2 for 5 days. Residual volumes of synovial fluid between 0.5 and 3 ml were inoculated into a BACTEC Peds Plus/F bottle, which was loaded into the BACTEC 9240 instrument in the computer-assigned position and incubated for 5 days. The BACTEC 9240 instrument was observed at 4-h intervals for positive signals.Microorganisms isolated from positive cultures were identified by standard biochemical techniques. All microorganisms were classified as either pathogens or contaminants on the basis of a review of the medical record by two of the authors of the present paper (F.R.C. and R.P.), who are also infectious disease physicians.For each organism species detected (and overall), comparisons of the detection rates of the two systems were assessed by the sign test. All calculated P values were two sided, and P values of Յ0.05 were considered statistically significant. RESULTSA total of 805 synovial fluid specimens met the criteria for inclusion in the study. Results for positive specimens are provided in Table 1. Microbial growth was produced by 74 cultures (9.2%) from 60 patients, yielding a total of 77 microorganisms. On the basis of medical hi...

Background: The successful introduction of new methods for managing medically unexplained symptoms in primary care is dependent to a large degree on the attitudes, experiences and expectations of practitioners. As part of an exploratory randomised controlled trial of reattribution training, we sought the views of participating practitioners on patients with medically unexplained symptoms, and on the value of and barriers to the implementation of reattribution in practice.

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Background‘Neoliberal’ work policies, austerity, NHS restructuring, and increased GP consultation rates provide the backdrop against increasing reports of GP burnout and an impending shortage of GPs.AimTo explore GPs’ experiences of workplace challenges and stresses, and their coping strategies, particularly focusing on understanding the impact of recent NHS workplace change.Design and settingStudy design was qualitative, with data collected from two focus groups and seven one-to-one telephone interviews.MethodFocus groups and one-to-one telephone interviews explored the experiences of GPs currently practising in England, recruited through convenience sampling. Data were collected using a semi-structured interview approach and analysed using thematic analysis.ResultsThere were 22 GP participants recruited: focus groups (n = 15) and interviews (n = 7). Interviewees understood GPs to be under intense and historically unprecedented pressures, which were tied to the contexts in which they work, with important moral implications for ‘good’ doctoring. Many reported that being a full-time GP was too stressful: work-related stress led to mood changes, sleep disruption, increases in anxiety, and tensions with loved ones. Some had subsequently sought ways to downsize their clinical workload. Workplace change resulted in little time for the things that helped GP resilience: a good work–life balance and better contact with colleagues. Although some GPs were coping better than others, GPs acknowledged that there was only so much an individual GP could do to manage their stress, given the external work issues they faced.ConclusionGPs experience their emotional lives and stresses as being meaningfully shaped by NHS factors. To support GPs to provide effective care, resilience building should move beyond the individual to include systemic work issues.

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The results for 281,797 blood culture sets of specimens collected from adult patients at the Mayo Clinic over an approximately 8-year period (1 November 1984 through 30 November 1992) were analyzed in order to determine whether there were differences in the types of microorganisms isolated over this time and to assess the usefulness of anaerobic culturing of blood. Each blood culture set consisted of two aerobic blood cultures (Septi-Chek [Becton Dickinson, Sparks, MD] and Isolator [Wampole Laboratories, Cranbury, NJ]) and one anaerobic culture (nonvented tryptic or trypticase soy broth [NVTSB; Difco Laboratories, Detroit, or Becton Dickinson]). The relative frequency of isolation of aerobic and facultatively anaerobic gram-positive bacteria and obligately anaerobic bacteria increased over the second half of the 1984-1992 surveillance period. The value of the NVTSB anaerobic blood culture was demonstrated for diagnosing bloodstream infections caused by certain facultatively anaerobic bacteria in addition to obligately anaerobic bacteria and supported the inclusion of the NVTSB anaerobic blood culture as a standard part of the three-component blood culture set used at this institution.

We recently demonstrated improved sensitivity of prosthetic joint infection (PJI) diagnosis using an automated blood culture bottle system for periprosthetic tissue culture [T. N. Peel et al., mBio 7(1):e01776-15, 2016, https://doi.org/ 10.1128/mBio.01776-15]. This study builds on the prior research by examining the optimal number of periprosthetic tissue specimens required for accurate PJI diagnosis. Current guidelines recommend five to six, which is impractical. We applied Bayesian latent class modeling techniques for estimating diagnostic test properties of conventional culture techniques (aerobic and anaerobic agars and thioglycolate broth) compared to inoculation into blood culture bottles. Conventional, frequentist receiver operating characteristic curve analysis was conducted as a sensitivity analysis. The study was conducted at Mayo Clinic, Rochester, MN, from August 2013 through April 2014 and included 499 consecutive patients undergoing revision arthroplasty from whom 1,437 periprosthetic tissue samples were collected and processed. For conventional periprosthetic tissue culture techniques, the greatest accuracy was observed when four specimens were obtained (91%; 95% credible interval, 77 to 100%), whereas when using inoculation of periprosthetic tissues into blood culture bottles, the greatest accuracy of diagnosis was observed when three specimens were cultured (92%; 95% credible intervals, 79 to 100%). Results of this study show that the greatest accuracy of PJI diagnosis is obtained when three periprosthetic tissue specimens are obtained and inoculated into blood culture bottles or four periprosthetic tissue specimens are obtained and cultured using standard plate and broth cultures. Increasing the number of specimens to five or more, per current recommendations, does not improve accuracy of PJI diagnosis.