Early assessment of blood culture negativity as a potential support tool for antimicrobial stewardship.

Objective: To assess whether 48-h negative blood culture (BC) bottles are still negative at the classic 120-h incubation endpoint and whether 48 h might be the time to make antimicrobial therapy decisions. Methods: Data from the first collected bottles from bloodstream infection (BSI) episodes of single patients were retrospectively analyzed. Probabilities of bottles being negative at the classic endpoint were calculated from 0 to 120 h of incubation. Results: Among BC-negative episodes (4018/4901 [82.0%]), most (2097/4018 (52.2%) occurred in medicine patients. At 48 h, probability was 100.0% (95% CI, 99.9-100.0) for all 4018 patients. Of these, 1244 (31.0%) patients remained on antibiotics until 120 h. Excluding 401 (32.2%) patients who received antibiotics for another (non-bloodstream) infection, 843 (67.8%) of 1244 patients could have merited early (48-h) discontinuation of antibiotics. Stopping treatment in these patients would have led to saving 5201 days of access (943 [18.1%] days), watch (3624 [69.7%] days), or reserve (634 [12.2%]) AWaRe groups' antibiotics, which correspond to 65.6% (5201/7928) of days of administered antibiotics in all 1244 patients. Conclusion: As an early indicator of BC negativity, the 48-h endpoint could reliably support antimicrobial stewardship, but the clinical judgment remains imperative especially when BSI is highly suspected.

Usefulness of differential time to positivity between catheter and peripheral blood cultures for diagnosing catheter-related bloodstream infection: Data analysis from routine clinical practice in the intensive care unit.

PURPOSE: To assess the accuracy of differential time to positivity (DTP) method for the diagnosis of catheter-related bloodstream infections (CRBSI) in the routine practice of our intensive care unit (ICU). MATERIALS AND METHODS: Over a five-year study period, ICU patients with a central venous catheter in place for ≥48 h and undergoing DTP test with catheter tip culture were analyzed. We investigated: the accuracy of DTP test with the usual threshold of 120 min in confirming the clinical suspicion of CRBSI; the most accurate threshold value of DTP to detect CRBSI; the diagnostic accuracy of the ratio (rather than the difference) between times to positivity. RESULTS: Among 278 episodes of paired blood cultures, 13% were CRBSIs. DTP value ≥120 min used for the diagnosis of CRBSI yielded 41% sensitivity and 74% specificity. Performance of DTP values in predicting CRBSI was low (AUC = 0.60 [95%CI: 0.48-0.72]). Cutoff value of the ratio between times to positivity was 0.80, with 46% sensitivity and 79% specificity. CONCLUSIONS: The routine use of the DTP method at any cutoff point has inadequate accuracy in detecting CRBSI in the real every day clinical practice. Not even the ratio between times to positivity seems to be clinically useful.

Efficient Recovery of Candida auris and Five Other Medically Important Candida Species from Blood Cultures Containing Clinically Relevant Concentrations of Antifungal Agents.

Candida auris and other Candida species (C. albicans, C. glabrata, C. parapsilosis, C. tropicalis, and C. krusei) are important causes of bloodstream infection. Early or prolonged treatment with antifungal agents is often required. The inhibitory effect of antifungal agents in the patients' bloodstream may compromise the sensitivity of blood culture (BC) to diagnose and/or monitor patients with candidemia. Using a clinical BC simulation model, we compared antimicrobial drug-neutralizing BC media in BacT/Alert FA PLUS (FAP) or Bactec Plus Aerobic/F (PAF) bottles with non-neutralizing BC media in Bactec Mycosis IC/F (MICF) bottles to allow Candida growth in the presence of 100%, 50%, or 25% peak serum level (PSL) antifungal concentrations. In total, 117 organism/antifungal combinations were studied, and Candida growth was detected after incubating bottles into BacT/Alert VIRTUO or Bactec FX BC systems. Compared to control (without antifungal) bottles, both FAP and PAF bottles with 100% PSL antifungal concentrations allowed 100% recovery for C. auris, C. glabrata, and C. parapsilosis, whereas recovery was below 100% for C. albicans, C. krusei, and C. tropicalis. MICF bottles were less efficient at 100%, 50%, or 25% PSL antifungal concentrations, for all Candida species, except for C. auris. While azoles and amphotericin B did not hinder Candida growth in FAP or PAF bottles, echinocandins allowed C. auris, C. glabrata, and C. parapsilosis to grow in FAP, PAF, or MICF bottles. Overall, the maximum time to detection was 4.6 days. Taken together, our findings emphasize the reliability of BCs in patients undergoing antifungal treatment for candidemia. IMPORTANCE While echinocandins remain the preferred antifungal therapy for candidemia, bloodstream infections caused by C. auris, C. glabrata, or, at a lesser extent, C. parapsilosis may be difficult to treat with these antifungal agents. This is in view of the high propensity of the above-mentioned species to develop antifungal resistance or tolerance during treatment. Azoles and amphotericin B are possible alternatives. Thus, optimizing the recovery of Candida from BCs is important to exclude the likelihood of negative BCs for Candida species, owing to the inhibitory effect of antifungal agents present in the blood sample with which BCs are inoculated. Consistently, our results about the recovery of medically important Candida species (including C. auris) from simulated BCs in BacT/Alert FAP, Bactec PAF, or Bactec MICF bottles containing clinically relevant antifungal concentrations add support to this research topic, as well as to the use of BCs for monitoring the clinical and therapeutic course of candidemia.

Chip-Based Molecular Evaluation of a DNA Extraction Protocol for Candida Species from Positive Blood Cultures.

The diagnosis of Candida bloodstream infection (BSI) may rely on a PCR-based analysis of a positive blood culture (PBC) obtained from the patient at the time of BSI. In this study, a yeast DNA extraction protocol for use on PBCs was developed and evaluated with the molecular mouse (MM) yeast blood (YBL) chip-based PCR assay, which allowed us to detect nine medically relevant Candida species. We studied 125 simulated or clinical PBCs for Candida species. A positive correlation between the DNA concentration and colony-forming unit count was found for simulated (Spearman's ρ = 0.58; p < 0.0001) and clinical (Spearman's ρ = 0.23, p = 0.09) PBCs. The extracted DNA yielded positive results with the MM YBL chip assay that agreed with the Candida species-level identification results for 63 (100%) of 63 isolates from simulated PBCs and 66 (99.5%) of 67 isolates from clinical PBCs. The false-negative result was for one C. tropicalis isolate that grew together with C. albicans in PBC. None of the 30 (Candida)-negative clinical BCs included as negative controls yielded a positive result with the MM YBL chip assay. Our DNA extraction protocol for the Candida species couples efficiency and simplicity together. Nevertheless, further studies are needed before it can be adopted for use with the MM YBL chip assay.

Susceptibility of Meropenem-Resistant and/or Carbapenemase-Producing Clinical Isolates of Enterobacterales (Enterobacteriaceae) and Pseudomonas aeruginosa to Ceftazidime-Avibactam and Ceftolozane-Tazobactam as Assessed by In Vitro Testing Methods.

This study aimed to assess the comparability of in vitro susceptibility testing methods to ceftazidime-avibactam (CZA) and ceftolozane-tazobactam (C/T). Meropenem-resistant and/or carbapenemase-producing clinical isolates of Enterobacterales (Enterobacteriaceae) and Pseudomonas aeruginosa were tested by both bioMérieux ETEST and VITEK-2 AST-N397 card and compared with a Micronaut AST-system broth microdilution (BMD) method. CZA and C/T MICs were interpreted using EUCAST breakpoints. Of the 153 Enterobacteriaceae isolates, 55.6% and 0.0% (VITEK 2) and 56.9% and 0.0% (ETEST and BMD) were susceptible to CZA and C/T, respectively. Of 52 P. aeruginosa isolates, 50.0% and 40.4% (VITEK 2, ETEST, and BMD) were susceptible to CZA and C/T, respectively. The essential agreement (EA) was 96.1% (197/205; VITEK 2 versus BMD) and 95.6% (196/205; ETEST versus BMD) for CZA testing, whereas EA was 98.0% (201/205; VITEK 2 versus BMD) and 96.6% (198/205; ETEST versus BMD) for C/T testing. The categorical agreement (CA) was 98.0% (201/205; VITEK 2 versus BMD) and 100% (ETEST versus BMD) for CZA testing, whereas CA was 100% (VITEK 2 versus BMD) and 100% (ETEST versus BMD) for C/T testing. Categorical errors regarded four Enterobacteriaceae isolates. VITEK 2 and ETEST yielded equivalent CZA and C/T susceptibility testing results, compared to the BMD method, in such a clinical context.

Simulated Pediatric Blood Cultures to Assess the Inactivation of Clinically Relevant Antimicrobial Drug Concentrations in Resin-Containing Bottles.

The bacteremia level as well as the administration of antibiotics before blood collection may significantly affect the recovery of bacterial pathogens from pediatric blood cultures in BacT/Alert Virtuo or Bactec FX BC systems, which remain the common techniques to diagnose bacteremia in pediatric patients. We simulated pediatric blood cultures with low or intermediate bacteremia level to evaluate BacT/Alert PF Plus and Bactec Peds Plus blood culture bottles for resin-based inactivation of 16 antibiotic-bacterium combinations. Overall, 105/192 (54.7%) of BacT/Alert PF Plus bottles and 69/192 (36.0%) of Bactec Peds Plus bottles allowed organisms to grow when exposed to antibiotics. In particular, both BacT/Alert PF Plus and Bactec Peds Plus bottles proved to be effective with piperacillin/tazobactam and Pseudomonas aeruginosa or with oxacillin and methicillin-susceptible Staphylococcus aureus (100% growth), whereas no effectiveness was apparent with ceftriaxone and Escherichia coli, Streptococcus agalactiae, or Streptococcus pneumoniae or with cefepime and E. coli (0% growth). In some relevant instances (e.g., with vancomycin and methicillin-resistant S. aureus or Streptococcus pneumoniae), BacT/Alert PF Plus bottles were superior to Bactec Peds Plus bottles. Together, these findings underscore the potentiality of resin-containing bottles to enhance diagnosis of bacteremia in pediatric patients on antimicrobial therapy. This is particularly true with one of the evaluated BC systems and with simulated intermediate bacteremia level only.

Risk Factors for Mortality in Adult COVID-19 Patients Who Develop Bloodstream Infections Mostly Caused by Antimicrobial-Resistant Organisms: Analysis at a Large Teaching Hospital in Italy.

The aim of this study was to characterize COVID-19 (SARS-CoV-2-infected) patients who develop bloodstream infection (BSI) and to assess risk factors associated with in-hospital mortality. We conducted a retrospective observational study of adult patients admitted for ≥48 h to a large Central Italy hospital for COVID-19 (1 March to 31 May 2020) who had or had not survived at discharge. We included only patients having blood cultures drawn or other inclusion criteria satisfied. Kaplan-Meier survival or Cox regression analyses were performed of 293 COVID-19 patients studied, 46 patients (15.7%) had a hospital-acquired clinically relevant BSI secondary to SARS-CoV-2 infection, accounting for 58 episodes (49 monomicrobial and 9 polymicrobial) in total. Twelve episodes (20.7%) occurred at day 3 of hospital admission. Sixty-nine species were isolated, including Staphylococcus aureus (32.8%), Enterobacterales (20.7%), Enterococcus faecalis (17.2%), Candida (13.8%) and Pseudomonas aeruginosa (10.3%). Of 69 isolates, 27 (39.1%) were multidrug-resistant organisms. Twelve (54.5%) of 22 patients for whom empirical antimicrobial therapy was inappropriate were infected by a multidrug-resistant organism. Of 46 patients, 26 (56.5%) survived and 20 (43.5%) died. Exploring variables for association with in-hospital mortality identified > 75-year age (HR 2.97, 95% CI 1.15-7.68, p = 0.02), septic shock (HR 6.55, 95% CI 2.36-18.23, p < 0.001) and BSI onset ≤ 3 days (HR 4.68, 95% CI 1.40-15.63, p = 0.01) as risk factors independently associated with death. In our hospital, mortality among COVID-19 patients with BSI was high. While continued vigilance against these infections is essential, identification of risk factors for mortality may help to reduce fatal outcomes in patients with COVID-19.

Time to Positivity of Blood Cultures Could Inform Decisions on Antibiotics Administration in Neonatal Early-Onset Sepsis.

(1) Background: Empirical antibiotics for suspected neonatal early-onset sepsis are often prolonged administered, even in the absence of clinical signs of infection, while awaiting the blood cultures results. The C-reactive protein is widely used to guide antibiotic therapy, although its increase in the first hours of life is not always evidence of infection. The aim of this study was to evaluate the time to positivity (TTP) of blood cultures (BC) that develop pathogens in our population of neonates and determine whether TTP could safely inform the decisions on empirical antibiotic discontinuation in neonatal early-onset sepsis and reduce the use of unnecessary antibiotics. (2) Methods: We retrospectively collected data of all newborns ≥ 34 weeks admitted to the Neonatal Intermediate-Care Unit at Policlinico "A. Gemelli" University Hospital (Rome, Italy) from 2014 to 2018, with suspected early-onset sepsis (EOS). The TTP was the time in hours from the first BC inoculation to the bacterial growth. We defined as positive BC only those with a pathogenic organism. (3) Results: In total, 103 out of 20,528 infants born in the five-year study period were admitted to our Neonatal Intermediate-Care Unit because of a suspected EOS and enrolled into the study. The mean TTP of pathogenic organisms was 17.7 ± 12.5 h versus 80.5 ± 55.8 h of contaminants (p = 0.003). We found ten positive BCs. The TTP of BC was lower than 12, 36, and 48 h in 80%, 90%, and 100% of cases, respectively. CRP levels on admission were similar in infants with a positive and negative BC (p = 0.067). The discontinuation of therapy in asymptomatic infants 48 h after initiation would have resulted in a saving of 217 days of antibiotics (31.1% of total days administered). (4) Conclusion: From our data, the TTP of blood cultures that develop pathogens is less than 48 h in 100% of cases. Therefore, in late preterm and full-term infants with suspected EOS, stopping empiric antibiotics 48 h after initiation may be a safe practice to reduce unnecessary antibiotic use, when blood cultures are negative and infants asymptomatic.

Implementation of the eazyplex® CSF direct panel assay for rapid laboratory diagnosis of bacterial meningitis: 32-month experience at a tertiary care university hospital.

We aimed to report a 32-month laboratory experience with the eazyplex® CSF direct panel assay for the rapid diagnosis of meningitis due to six most common bacterial species (Escherichia coli, Haemophilus influenzae, Listeria monocytogenes, Neisseria meningitidis, Streptococcus agalactiae, and Streptococcus pneumoniae). We included all cerebrospinal fluid (CSF) samples from patients admitted with a clinical suspicion of meningitis/encephalitis between May 2016 and December 2018 at our hospital. In addition to the eazyplex® assay, both Gram stain microscopy and culture were performed, and results were confirmed with 16S rRNA PCR/sequencing. Patients' demographics and relevant clinical information were collected. Of 135 studied patients, 44 (32.6%) had a microbiologically documented diagnosis of meningitis. Overall, we identified 21 S. pneumoniae, 10 N. meningitidis, 6 L. monocytogenes, 3 E. coli, 2 Streptococcus pyogenes, 1 S. agalactiae, and 1 Citrobacter koseri as aetiological agents. The eazyplex® assay allowed identification in 40 (90.9%) cases, with four not identified cases due to microorganisms not included in the panel at the time of testing. Thirty-two (72.7%) cases had positive culture results, whereas 28 (63.6%) cases had positive Gram stain results. Notably, combining Gram stain and eazyplex® assay allowed identification in 100% of cases. After notification of rapid results, physicians modified the empiric antibiotic therapy, which became appropriate in three patients (all with L. monocytogenes meningitis). The eazyplex® CSF panel assay worked better than culture in detecting the most common agents of bacterial meningitis and accelerated the diagnosis leading to timely initiation or continuation of appropriate antibiotic therapy.

Corrigendum: In vitro Evaluation of BACT/ALERT® VIRTUO®, BACT/ALERT 3D®, and BACTEC™ FX Automated Blood Culture Systems for Detection of Microbial Pathogens Using Simulated Human Blood Samples.

[This corrects the article DOI: 10.3389/fmicb.2019.00221.].

Simplified Testing Method for Direct Detection of Carbapenemase-Producing Organisms from Positive Blood Cultures Using the NG-Test Carba 5 Assay.

We directly tested 484 organisms from clinical (n = 310) and simulated (n = 174) positive blood cultures using the NG-Test Carba 5 assay for carbapenemase-producing Enterobacterales detection. The assay identified all but 4 of the KPC (170/171), OXA-48-like (22/22), VIM (19/21), and NDM (14/15) producers with no false positives. Among the clinical Klebsiella pneumoniae organisms tested, 122 of 123 KPC, 1 of 1 OXA-48-like, and 1 of 2 VIM producers were detected by the assay. Some VIM and NDM producers yielded scant but still-readable bands with the assay. No organisms produced the IMPs that the assay was designed to detect.

Direct use of eazyplex® SuperBug CRE assay from positive blood cultures in conjunction with inpatient infectious disease consulting for timely appropriate antimicrobial therapy in Escherichia coli and Klebsiella pneumoniae bloodstream infections.

Objectives: To describe a rapid workflow based on the direct detection of Escherichia coli (Ec) and Klebsiella pneumoniae (Kp) producing CTX-M extended-spectrum ß-lactamase (ESBL) and/or carbapenemases (eg, KPC, VIM) from blood cultures (BCs) and the infectious disease (ID) consulting for timely appropriate antimicrobial therapy. Methods: This observational, retrospective study included adult patients with a first episode of Ec or Kp bloodstream infection (BSI) in a large Italian university hospital, where an inpatient ID consultation team (IDCT) has been operational. Results from the BCs tested for detecting bla CTX-M, bla KPC, bla NDM, bla OXA-48-like, and bla VIM genes by the eazyplex® SuperBug CRE assay in Ec and Kp organisms had been notified for antimicrobial therapy consulting. Results: In 321 BSI episodes studied, we found that 151 (47.0%) of Ec or Kp organisms harbored bla CTX-M and/or bla KPC and/or bla VIM (meantime from BC collection: 18.5 h). Empirical antimicrobial treatment was appropriate in 21.8% (33/151) of BSIs, namely 5.9% (3/51) of BSIs caused by KPC/VIM producers and 30.0% (30/100) of BSIs caused by CTX-M producers. After notification of results, the IDCT modified antimicrobial therapy (mean time from BC collection: 20 h) such that the proportion of appropriate treatments increased to 84.8% (128/151) of BSIs, namely 70.6% (36/51) of BSIs caused by KPC/VIM producers and 92.0% (92/100) of BSIs caused by CTX-M producers. Conclusion: Our study shows that a rapid diagnostic-driven clinical strategy allowed for early prescription of potentially effective antimicrobial therapy in BSIs caused by CTX-M ESBL- and/or KPC/VIM carbapenemase-producing Ec and Kp organisms.

In vitro Evaluation of BACT/ALERT® VIRTUO®, BACT/ALERT 3D®, and BACTEC™ FX Automated Blood Culture Systems for Detection of Microbial Pathogens Using Simulated Human Blood Samples.

Blood culture (BC) is still the standard for diagnosing bloodstream infections (BSIs), especially those caused by bacteria and fungi. Infection-complicating sepsis or septic shock often occurs at BSI onset, making necessary to improve the diagnostic yield of positive BCs. Among the BC systems currently available, the BACT/ALERT® VIRTUO® (VIRTUO) system has been developed to shorten time to detection (TTD) of positive BCs. In this study, we assessed TTD for 330 clinically relevant species including 14 Gram-positive, 14 Gram-negative, and 5 yeast isolates in spiked human blood samples that were tested in parallel with VIRTUO BACT/ALERT® 3D (BTA3D) and BACTEC™ FX (BACTEC) systems. We inoculated 30 colony-forming unit (CFU) from each microbial suspension into BACT/ALERT® Plus or BACTEC™ Plus (aerobic/anaerobic or pediatric) BC bottles, and we used two different blood volumes to simulate, respectively, the BCs collected from adult and pediatric patients. Of 2,610 bottles tested, 2,600 (99.6%) signaled positive in the three systems. Only the BACTEC system did not detect Staphylococcus lugdunensis isolates in anaerobic bottles. Among adult simulated cultures, the median TTD was significantly shorter for aerobic/anaerobic bottles incubated in VIRTUO (11.6 h and 10.1 h) compared to bottles incubated in either BTA3D (13.3 and 12.3 h) or BACTEC (13.5 and 12.2 h) system. Among pediatric simulated cultures, the median TTD was significantly shorter for bottles incubated in VIRTUO (11.2 h) compared to bottles incubated in either the BTA3D (13.0 h) or BACTEC (12.5 h) system. Compared to BTA3D and/or BACTEC systems, VIRTUO allowed faster growth detection for most of the 33 microbial species tested. Notable examples were Salmonella spp. (7.4 h by VIRTUO vs. 10.1 h and 9.2 h by either BTA3D or BACTEC) and Streptococcus agalactiae (8.1 h by VIRTUO vs. 10.3 and 9.4 h by either BTA3D or BACTEC). The few notable exceptions included Stenotrophomonas maltophilia and some Candida species. Together, these findings confirm that VIRTUO has greater potential of improving the laboratory detection of bacteremia and fungemia than the progenitor BTA3D or the competitor BACTEC system.

Age-related Trends in Adults with Urinary Tract Infections Presenting to the Emergency Department: A 5-Year Experience.

INTRODUCTION: Urinary tract infections (UTIs) are among the most common bacterial infections, affecting 150 million people worldwide each year. Importantly, the incidence of UTI increases markedly with age. The increasing resistance to empirically prescribed antimicrobial agents complicates the management of this disease. This makes UTI an important issue in increasingly aging population and updated epidemiological investigation is advisable. To understand the epidemiological variation in UTI resistance patterns among differently aged populations, we conducted a retrospective study among patients presenting to the emergency department (ED) of a large tertiary-care hospital in Italy during January 2013 and June 2017. METHODS: 1281 patients who presented with UTI symptoms to the ED, were stratified into four age categories: young adults (18-44 years old;), adults (45-64), the elderly (65-84), and the oldest old (≥ 85). Inclusion criteria were urine collected in ED patients with UTI symptoms and first positive culture from one given patient in a given year. RESULTS: 362 (28.2%) patients had a urine culture with positive result, leading to a total of 459 germs isolated, stratified into four categories: young adults (58 isolates, 12.6%), adults (98, 21.4%), the elderly (174, 37.9%), and the oldest old (129, 28.1%). Escherichia coli represents the 60% of all monomicrobial infections, followed in frequency by Klebsiella pneumoniae (15%), and Enterococcus faecalis (5%). The other 20% of the infections are caused by various germs. The most common association of germs in polymicrobial is E. coli + E. faecalis, accounting for the 28% of all infections. Overall, we found a peak of susceptibility to amoxicillin (AMX) in the oldest old ( 81%), significantly higher compared to young adults (54%), adults (47%) and elderly (35%) (p<0,001). For ciprofloxacin (CIP) there is a greater susceptibility in the young adult (55.5%), but not so marked compared to the other three groups; for fosfomicin (FOS) the susceptibility was greater in the group of adults (60%) compared to young adults, elderly and the oldest old. Also for trimethoprim/ sulfamethoxazole (TMP-SMX) we found greater susceptibility in the adult group (60%), followed by the oldest old (57,6%), young adults (49%) and elderly (47%). CONCLUSION: Age-related differences in antimicrobial-resistant microorganisms were evident for adults with UTI, and could potentially contribute to the risk of inappropriate empirical therapy in elderly patients. Thus, different empirical antimicrobial regimens should be considered for distinct age groups.

Incidence and antimicrobial resistance trends in bloodstream infections caused by ESKAPE and Escherichia coli at a large teaching hospital in Rome, a 9-year analysis (2007-2015).

The proportion of antimicrobial resistance (AMR) among the ESKAPE and Escherichia coli (ESKAPEEc) pathogens causing bloodstream infection (BSI) increased worldwide. We described longitudinal trends in ESKAPEEc BSI and AMR over 9 years (2007-2015) at a large teaching hospital in Italy. Of 9720 unique BSI episodes, 6002 (61.7%) were caused by ESKAPEEc pathogens. The majority of these episodes (4374; 72.9%) were hospital-onset infections. The most frequent pathogen was E. coli (32.8%), followed by Staphylococcus aureus (20.6%), Klebsiella pneumoniae (16.1%), and Pseudomonas aeruginosa (11.6%). There was a significant increase of hospital-onset K. pneumoniae (from 2.3 to 5.0 per 10,000 patient-days; P = 0.001) and community-onset E. coli (from 3.3 to 9. 1 per 10,000 emergency admissions; P = 0.04) BSIs. Among hospital-onset BSIs, increases of extended-spectrum ß-lactamase (ESBL)-producing E. coli (from 25.4 to 35.2%, P = 0.006), carbapenemase-producing K. pneumoniae (from 4.2 to 51.6%, P < 0.001), and methicillin-resistant S. aureus (from 33.9 to 44.4%, P < 0.001) BSIs were observed between the 2007-2009 and 2010-2012 study periods. In contrast, a decrease of BSIs caused by P. aeruginosa resistant to ceftazidime (from 45.5 to 28.2%, P < 0.001), ciprofloxacin (from 46 to 36.3%, P = 0.05), and meropenem (from 55 to 39.9%, P = 0.03) was observed through all 9 years of the study period. Among community-onset BSIs, increases of BSIs caused by ESBL-producing E. coli (from 28.6 to 42.2%, P = 0.002) and carbapenemase-producing K. pneumoniae (from 0 to 17.6%) were observed between the 2007-2009 and 2010-2012 study periods. Our findings show increased rates of BSI and relative AMR for specific pathogen-health care setting combinations, and call for continued active surveillance and infection control policies.

A rapid diagnostic workflow for cefotaxime-resistant Escherichia coli and Klebsiella pneumoniae detection from blood cultures by MALDI-TOF mass spectrometry.

BACKGROUND: Nowadays, the global spread of resistance to oxyimino-cephalosporins in Enterobacteriaceae implies the need for novel diagnostics that can rapidly target resistant organisms from these bacterial species. METHODS: In this study, we developed and evaluated a Direct Mass Spectrometry assay for Beta-Lactamase (D-MSBL) that allows direct identification of (oxyimino)cephalosporin-resistant Escherichia coli or Klebsiella pneumoniae from positive blood cultures (BCs), by using the matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) technology. RESULTS: The D-MSBL assay was performed on 93 E. coli or K. pneumoniae growing BC samples that were shortly co-incubated with cefotaxime (CTX) as the indicator cephalosporin. Susceptibility and resistance defining peaks from the samples' mass spectra were analyzed by a novel algorithm for bacterial organism classification. The D-MSBL assay allowed discrimination between E. coli and K. pneumoniae that were resistant or susceptible to CTX with a sensitivity of 86.8% and a specificity of 98.2%. CONCLUSION: The proposed algorithm-based D-MSBL assay, if integrated in the routine laboratory diagnostic workflow, may be useful to enhance the establishment of appropriate antibiotic therapy and to control the threat of oxyimino-cephalosporin resistance in hospital.

Susceptibility Testing of Common and Uncommon Aspergillus Species against Posaconazole and Other Mold-Active Antifungal Azoles Using the Sensititre Method.

We tested 59 common and 27 uncommon Aspergillus species isolates for susceptibility to the mold-active azole antifungal agents itraconazole, voriconazole, and posaconazole using the Sensititre method. The overall essential agreement with the CLSI reference method was 96.5% for itraconazole and posaconazole and was 100% for voriconazole. By the Sensititre method as well as the CLSI reference method, all of 10 A. fumigatus isolates with a cyp51 mutant genotype were classified as being non-wild-type isolates (MIC > epidemiological cutoff value [ECV]) with respect to triazole susceptibility.