An optimized algorithm with improved turnaround time for detection of carbapenemase-producing Enterobacterales using the NG Test CARBA 5 in a routine laboratory.

Introduction. Rapid and reliable detection of carbapenemase-producing Enterobacterales (CPE) from surveillance cultures is critical in supporting a good infection control programme. We implemented a new algorithm for CPE detection incorporating the NG Test CARBA 5 in January 2019.Aim. Our goals were to compare turnaround time (TAT), costs and staff requirements between the old and new algorithm, and to evaluate the performance of the CARBA 5 test directly on colonies grown on CARBA Smart agar.Methodology. We analysed and compared the TAT of CPE surveillance cultures processed using the old and new CPE screening algorithm. The total actual reagent costs and staff requirements for the new CPE algorithm were compared with the estimated costs and staff requirements of the old CPE algorithm.Results. Of 197 isolates included in the evaluation of the new algorithm, 64 were positive for carbapenemases by both CARBA 5 and Xpert Carba-R assay. Of the 133 that were negative, two were found to harbour NDM and IMI genotypes. Significant improvements in TAT were achieved with 88.7 % of cultures with CPE, reported on the same day as growth was observed on CARBA Smart agar compared to none in the old algorithm. The new algorithm incurred lower costs and, based on our workload, the new algorithm is estimated to save 28.9 man-hours annually.Conclusion. CARBA 5 performs well on colonies growing on CARBA Smart agar and significant improvements in TAT can be achieved without incurring additional costs or staff requirements.

Audit of a multidisciplinary approach to improve management of community-acquired pneumonia.

BACKGROUND: Community-acquired pneumonia (CAP) is a frequent cause of morbidity, mortality and hospital admission worldwide. An adequate choice of empirical antibiotic treatment and appropriate severity assessment of the disease are key aspects in the management of CAP. OBJECTIVE: To audit the adherence to standards of care, such as empirical prescribing of antibiotics, and evaluate the current multidisciplinary approach to the management of CAP. METHOD: Records of patients with CAP were identified and examined for CURB65 score documentation, discussion notes with microbiology and prescribed antibiotic treatments. RESULTS: Out of the 62 patients identified, 32 had a CURB65 score documented in their medical notes and 59 had documented chest X-ray findings. 85.5% of cases were compliant with antibiotic prescribing guidelines. CONCLUSION: The multidisciplinary approach has considerably improved compliance with most of the standards, especially adherence to empirical antibiotic guidelines, and ultimately the standard of care for patients with CAP.

Diagnostic Accuracy of BD Phoenix CPO Detect for Carbapenemase Production in 190 Enterobacteriaceae Isolates.

The rapid and accurate detection of carbapenemase-producing Enterobacteriaceae (CPE) is necessary for patient management and infection control measures. We compared the performance of the BD Phoenix CPO Detect with that of a homemade Carba NP assay and a modified carbapenem inactivation method (mCIM) by challenging all 3 assays with 190 isolates of Enterobacteriaceae with meropenem MICs of >0.125 mg/liter. A total of 160 isolates produced KPC-, IMI-1-, NDM-, IMP-, and OXA-type carbapenemases, while 30 isolates were negative for carbapenemase production. The sensitivity and specificity were 90.6% (95% confidence interval [CI], 85.0% to 94.7%) and 100.0% (95% CI, 88.4% to 100.0%), respectively, for the Carba NP; 100.0% (95% CI, 97.7% to 100.0%) and 96.7% (95% CI, 82.7% to 99.9%), respectively, for the mCIM; and 89.4% (95% CI, 83.5% to 93.7%) and 66.7% (95% CI, 47.2% to 82.7%), respectively, for the BD Phoenix CPO Detect. In particular, the BD CPO Detect failed to detect a significant number of CPE with IMI-1. While the BD Phoenix CPO Detect is able to classify carbapenemases and is built into routine susceptibility testing with the potential to reduce the time to CPE detection, its low specificity means that a positive result will need confirmatory testing by another method.

Acid-suppression medications and bacterial gastroenteritis: a population-based cohort study.

AIMS: To investigate whether acid-suppression medicines (ASMs) increase the risk of bacterial gastroenteritis. METHODS: A population-based, propensity-score matched cohort study using a record-linkage database in Tayside, UK. The study consisted of 188 323 exposed to ASMs (proton-pump inhibitors and histamine-2 receptor antagonists) and 376 646 controls (a propensity-score matched cohort from the rest of population who were not exposed to ASMs) between 1999 and 2013. The main outcome measure was a positive stool test for Clostridium difficile, Campylobacter, Salmonella, Shigella or Escherichia coli O157. The association between ASMs and risk of bacterial gastroenteritis was assessed by a Cox regression model. RESULTS: There were 22 705 positive test results (15 273 C. difficile [toxin positive], 6590 Campylobacter, 852 Salmonella, 129 Shigella and 193 E. coli O157, not mutually exclusive) with a total of 5 729 743 person-years follow up time in Tayside, 1999-2013. The adjusted hazard ratios for culture positive diarrhoea for the proton-pump inhibitors and histamine-2 receptor antagonists exposed vs. unexposed cohort were 2.72 (95% confidence interval [CI] 2.33, 3.17) during follow-up time for samples submitted from the community and 1.28 (95% CI 1.08, 1.52) for samples submitted from hospitals. Compared with the unexposed cohort, patients in the exposed group had increased risks of C. difficile and Campylobacter [adjusted hazard ratios of 1.70 (95% CI 1.28, 2.25), 3.71 (95% CI 3.04, 4.53) for community samples, and 1.42 (95% CI 1.17, 1.71), 4.53 (95% CI 1.75, 11.8) for hospital samples, respectively]. CONCLUSIONS: The results suggest that community prescribed ASMs were associated with increased rates of C. difficile and Campylobacter positive gastroenteritis in both the community and hospital settings.

Audit of the management of patients at high risk of carbapenemase-producing enterobacteriaceae (CPE): Are we ready?

BACKGROUND: Incidence of carbapenemase-producing enterobacteriaceae (CPE) in the UK is increasing. In 2013, Public Health England (PHE) published a toolkit to control spread of CPE within healthcare settings. AIM: To assess compliance to hospital CPE policy (adapted from PHE) in the identification, isolation and screening of suspected CPE patients. METHODS: Admission booklets of 150 patients were evaluated to see whether the relevant section had been completed to identify high-risk CPE patients. Where necessary, patients were interviewed or their GPs were contacted to assess their CPE risk. Additionally, 28 patients screened for CPE were audited to assess compliance to screening and isolation. FINDINGS: Only 23 patients out of 147 (15.6%) were risk assessed on admission. Risk status of 27 (18.4%) patients could not be assessed due to lack of data. Fifteen patients out of 28 (54%) screened for CPE were identified and isolated on admission. Ten out of 19 patients (53%) had three screens 48 h apart. DISCUSSION: This audit highlights difficulties in screening based on individual risk factors as the majority of patients were not screened on admission and documentation on isolation and screening was poor. More needs to be done to raise awareness of the requirements for routine assessment, isolation and screening.

Value of repeat testing using Cepheid GeneXpert CT/NG for indeterminate PCR results when diagnosing Chlamydia trachomatis and Neisseria gonorrhoeae.

Nucleic acid amplification tests (NAATs) are the most sensitive method for diagnosing chlamydia and gonorrhoea. We use the COBAS 4800 CT/NG combined assay (Roche Molecular Diagnostics, CA, USA), and whilst the majority of samples yield definitive results, a small proportion are reported as indeterminate. In these instances, it is usual practice to request repeat samples which delays diagnosis. This audit was twofold: first to establish the proportion of indeterminate results with current NAAT testing requiring re-sampling. Second, to determine whether a second NAAT such as Cepheid GeneXpert CT/NG assay (Cepheid, CA, USA) could be used on initial indeterminate samples to resolve indeterminate results, therefore reducing need for repeat sampling. During 2012, 144/21,931 (0.66%) samples were indeterminate for Neisseria gonorrhoeae, Chlamydia trachomatis or both, and a repeat sample was received in only 51.77% of patients with final results being delayed for more than 24 h. Over the next six months, there were 77/9472 (0.81%) indeterminate results. After an evaluation and introduction of the Cepheid assay, the number of indeterminate results fell to 9 (0.10%). Thus, use of the Cepheid assay significantly reduced indeterminate results, reduced reliance on a repeat sampling and significantly improved turnaround time, laboratory workflow and patient experience.

Aggregatibacter aphrophilus in a patient with recurrent empyema: a case report.

INTRODUCTION: Aggregatibacter aphrophilus (formerly Haemophilus aphrophilus and H. paraphrophilus) is classically associated with infective endocarditis. Other infections reported in the literature include brain abscess, bone and joint infections and endophthalmitis. There are only two cases of empyema ever reported due to this organism. We report the isolation of A. aphrophilus from pleural fluid on three separate hospital admissions in a patient with recurrent empyema. CASE PRESENTATION: A 65-year-old female patient of Caucasian origin presented with a three-week history of fever, shortness of breath and dry cough. She was found to have a pleural empyema so a chest drain was inserted and a sample of pus was sent to the microbiology laboratory. After overnight incubation, a chocolate blood agar plate incubated in 5% carbon dioxide showed a profuse growth of small, round, glistening colonies which were identified as Gram-negative coccobacilli. They were oxidase- and catalase-negative. Biochemical testing using RapID NH confirmed the identity of the organism as A. aphrophilus. It was susceptible to amoxicillin, levofloxacin and doxycycline. Our patient was treated with intravenous amoxicillin with clavulanic acid and clarithromycin followed by oral doxycycline, but was re-admitted twice over the next three months with recurrent empyema and the same organism was isolated. Each episode was managed with chest drainage and a six-week course of antibiotic--doxycycline for the second episode and amoxicillin for the third episode, after which she has remained well. CONCLUSION: This is the first case report of recurrent empyema due to A. aphrophilus. Our patient had no underlying condition to explain the recurrence. Although our isolate was doxycycline susceptible, our patient had recurrent infection after treatment with this antibiotic, suggesting that this antibiotic is ineffective in treatment of deep-seated A. aphrophilus infection. This organism can be difficult to identify in the laboratory because, unlike closely related Haemophilus spp., it is oxidase-negative, catalase-negative and X and V independent.