Abbott ARCHITECT Syphilis TP Chemiluminescent Immunoassay Accurately Diagnoses Past or Current Syphilis in Pregnancy.

OBJECTIVE: We evaluate diagnostic accuracy of the ARCHITECT chemiluminescent immunoassay (CIA) screening test in pregnancy, and evaluate pregnancy outcomes among screen-positive women. STUDY DESIGN: Samples from routine prenatal rapid plasma reagin (RPR) tests were collected between June 22 and August 18, 2017 and frozen. Samples were batch-tested with the Abbott ARCHITECT syphilis TP immunoassay (CIA, index test). We calculated sensitivity, specificity, predictive value, and false positivity. We compared pregnancy and neonatal outcomes among screen-positive women. RESULTS: Of 1,602 specimens, 35 (2.2%) were RPR + ; of those, 24 (69%) were CIA +/Treponema pallidum particle agglutination assay (TPPA)+ and 11 (31%) were CIA-/TPPA-. Of 1,567 RPR- specimens, 14 (0.9%) were CIA + ; of those, 13 (93%) were TPPA + , and one (7%) had a false positive CIA test. Sensitivity of the CIA (95% CI) was 100% (90.5-100%), specificity 99.9% (99.6-100%), positive predictive value 97.4% (86.2-99.9%), and false positive rate 0.06% (0.002-0.4%) for current or past syphilis. Among 37 CIA +/TPPA+ women, seven (19%) had RPR-negative status (Group 1), 11 (30%) had previously treated syphilis (Group 2), and 19 (51%) had active infection (Group 3). One stillbirth occurred in a woman with early, active syphilis identified at delivery; no adverse perinatal outcomes occurred among women in Groups 1 or 2. CONCLUSION: The ARCHITECT syphilis TP immunoassay accurately diagnoses current or past syphilis in pregnancy. Clinical history and staging remain essential using a reverse algorithm.

Multidrug-resistant Pseudomonas aeruginosa from sputum of patients with cystic fibrosis demonstrates a high rate of susceptibility to ceftazidime-avibactam.

PURPOSE: Ceftazidime-avibactam is a novel antimicrobial combining a third-generation cephalosporin with a non-ß-lactam ß-lactamase inhibitor that was recently approved to treat Gram-negative hospital- and ventilator-acquired pneumonia. The use of ceftazidime-avibactam to treat Pseudomonas aeruginosa respiratory infections in patients with cystic fibrosis (CF) has not been evaluated. In this study, we assessed the ceftazidime-avibactam susceptibility of multidrug-resistant (MDR) P. aeruginosa sputum isolates from adults with CF. METHODS: Sputum was collected from individuals with CF, aged ≥18 years, known to be colonized with MDR P. aeruginosa, and tested for susceptibility to 11 different antipseudomonal antimicrobial agents. Isolates were included in the analysis if they were resistant to both ceftazidime and at least one agent in ≥3 different antimicrobial categories routinely used to treat P. aeruginosa. Subject demographics and clinical characteristics were collected. Ceftazidime-avibactam-resistant isolates were screened for the presence of ß-lactam-resistant mechanisms. RESULTS: Thirty-two P. aeruginosa isolates were analyzed, of which 23 isolates were sensitive to ceftazidime-avibactam (71.9%). Ten of the isolates were mucoid and 22 isolates were nonmucoid, both demonstrating >70% susceptibility to ceftazidime-avibactam. The most notable difference in the subjects with resistant strains was an older age and lower body mass index (BMI). Ceftazidime-avibactam-resistant strains showed elevated AmpC expression in >60% of the strains and loss of OprD detection in >70% of the strains. CONCLUSION: Ceftazidime-avibactam demonstrated a significant in vitro activity against highly resistant P. aeruginosa sputum isolates from individuals with CF. Further evaluation of the cause of resistance and clinical impact of ceftazidime-avibactam in CF patients with MDR P. aeruginosa is warranted.

Ceftolozane/tazobactam sensitivity patterns in Pseudomonas aeruginosa isolates recovered from sputum of cystic fibrosis patients.

Ceftolozane/tazobactam is a combination intravenous antibiotic with potentially important activity against drug-resistant Gram-negative organisms. Ceftolozane/tazobactam's in vitro activity was evaluated in 30 samples collected from 23 adult cystic fibrosis patients with extended and pan-resistant Pseudomonas aeruginosa in 2015. Testing results demonstrated that 30% of the isolates were susceptible,13% were intermediate, and 57% were resistant. This suggests that ceftolozane/tazobactam may be a useful antibiotic in carefully selected, multidrug-resistant Pseudomonas isolates.

Evaluation of the Accelerate Pheno System: Results from Two Academic Medical Centers.

Rapid diagnostic tests are needed to improve patient care and to combat the problem of antimicrobial resistance. The Accelerate Pheno system (Accelerate Diagnostics, Tucson, AZ) is a new diagnostic device that can provide rapid bacterial identification and antimicrobial susceptibility test (AST) results directly from a positive blood culture. The device was compared to the standard of care at two academic medical centers. There were 298 blood cultures included in the study, and the Accelerate Pheno system provided a definitive identification result in 218 instances (73.2%). The Accelerate Pheno system provided a definitive and correct result for 173 runs (58.1%). The Accelerate Pheno system demonstrated an overall sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 94.7%, 98.9%, 83.7%, and 99.7%, respectively. An AST result was available for analysis in 146 instances. The overall category agreement was 94.1% with 12 very major errors, 5 major errors, and 55 minor errors. After a discrepancy analysis, there were 5 very major errors and 4 major errors. The Accelerate Pheno system provided an identification result in 1.4 h and an AST result in 6.6 h; the identification and AST results were 41.5 h and 48.4 h faster than those with the standard of care, respectively. This study demonstrated that the Accelerate Pheno system is able to provide fast and accurate organism identification and AST data. A limitation is the frequency with which cultures required the use of alternative identification and AST methods.

Bacteremia and Septic Arthritis due to a Nontoxigenic Strain of Clostridium difficile in a Patient With Sickle Cell Disease.

A 22-year-old female with sickle cell disease presented with fevers, bilateral knee pain, and lethargy. Laboratory data revealed a leukocytosis and lactic acidosis. Blood and synovial fluid cultures grew a non-toxin-producing strain of Clostridium difficile. This case highlights the fact that nontoxigenic Clostridium difficile can cause significant disease.