Citations

ABSTRACT Culture of periprosthetic tissue specimens in blood culture bottles is more sensitive than conventional techniques, but the impact on laboratory workflow has yet to be addressed. Herein, we examined the impact of culture of periprosthetic tissues in blood culture bottles on laboratory workflow and cost. The workflow was process mapped, decision tree models were constructed using probabilities of positive and negative cultures drawn from our published study (T. N. Peel, B. L. Dylla, J. G. Hughes, D. T. Lynch, K. E. Greenwood-Quaintance, A. C. Cheng, J. N. Mandrekar, and R. Patel, mBio 7:e01776-15, 2016, https://doi.org/10.1128/mBio.01776-15 ), and the processing times and resource costs from the laboratory staff time viewpoint were used to compare periprosthetic tissues culture processes using conventional techniques with culture in blood culture bottles. Sensitivity analysis was performed using various rates of positive cultures. Annualized labor savings were estimated based on salary costs from the U.S. Labor Bureau for Laboratory staff. The model demonstrated a 60.1% reduction in mean total staff time with the adoption of tissue inoculation into blood culture bottles compared to conventional techniques (mean ± standard deviation, 30.7 ± 27.6 versus 77.0 ± 35.3 h per month, respectively; P < 0.001). The estimated annualized labor cost savings of culture using blood culture bottles was $10,876.83 (±$337.16). Sensitivity analysis was performed using various rates of culture positivity (5 to 50%). Culture in blood culture bottles was cost-effective, based on the estimated labor cost savings of $2,132.71 for each percent increase in test accuracy. In conclusion, culture of periprosthetic tissue in blood culture bottles is not only more accurate than but is also cost-saving compared to conventional culture methods.

ABSTRACT 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.

ABSTRACT 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. IMPORTANCE Prosthetic joint infections are a devastating complication of arthroplasty surgery. Despite this, current microbiological techniques to detect and diagnose infections are imperfect. This study examined a new approach to diagnosing infections, through the inoculation of tissue samples from around the prosthetic joint into blood culture bottles. This study demonstrated that, compared to current laboratory practices, this new technique increased the detection of infection. These findings are important for patient care to allow timely and accurate diagnosis of infection.

ABSTRACTA 57-year-old woman with common variable immune deficiency and liver failure of unknown etiology presented with recurrent fevers over a 5-month period. She was found to haveHelicobacter canisbacteremia. Immunocompromised hosts with exposure to cats or dogs may be at risk for infection with this organism, which may be challenging to diagnose.

In gene-targeted mouse models for cystic fibrosis (CF), the disease is mainly manifested by mucus obstruction in the intestine. To explore the mucus composition, mucins insoluble and soluble in 6M guanidinium chloride were purified by three rounds of isopycnic ultracentrifugation from the small and large intestines of CF mice (Cftrm1UNC/Cftrm1UNC) and compared with wild-type mice. The amino acid composition was typical of that for mucins and showed increased amounts of the insoluble (2.5-fold increase) and soluble (7-fold increase) mucins in the small intestine of the CF mice compared with wild-type mice. Mucins from the large intestine of both wild-type and CF mice showed a high but constant level of fucosylation. In contrast, the insoluble and soluble mucins of the small intestine in CF mice revealed a large increase in fucose, whereas those of wild-type mice contained only small amounts of fucose. This increased fucosylation was analysed by releasing the O-linked oligosaccharides followed by GC-MS. NMR spectroscopy revealed that the increased fucosylation was due to an increased expression of blood group H epitopes (Fucα1-2Gal-). Northern-blot analysis, using a probe for the murine Fucα1-2 fucosyltransferase (Fut2), showed an up-regulation of this mRNA in the small intestine of the CF mice, suggesting that this enzyme is responsible for the observed increase in blood group H-type glycosylation. The reason for this up-regulation could be a direct or indirect effect of a non-functional CF transmembrane conductance regulator (CFTR) caused by the absence of CFTR channel.

ABSTRACT An evaluation was undertaken to determine the utility of the BACTEC Peds Plus/F bottle and the BACTEC 9240 instrument (Becton Dickinson Diagnostic Instrument Systems, Sparks, Md.) for the detection of clinically significant microorganisms in synovial fluid specimens. The Peds Plus/F bottle was used because in our laboratory the quantity of synovial fluid available for culture is frequently in the range of 0.5 to 3.0 ml. The culture results obtained with the Peds Plus/F bottle were compared to those obtained by a conventional agar plate method for a total of 805 synovial fluid specimens. Microbial growth was produced by 74 cultures (9.2%) from 60 patients, yielding a total of 77 microorganisms. Organisms were classified as pathogens ( n = 62), contaminants ( n = 12), or indeterminate ( n = 3) on the basis of a review of the patients' medical histories. Culture using BACTEC Peds Plus/F bottle detected statistically significantly more pathogens overall (62 versus 51 pathogens [ P = 0.001]) and statistically fewer contaminants overall (1 versus 11 contaminants [ P = 0.006]) than culture by the agar plate method. These results indicate the superior performance of the BACTEC Peds Plus/F bottle over the conventional agar plate method for the detection of clinically significant microorganisms from synovial fluid specimens.