Changes in the early mortality of adult patients with carbapenem-resistant Acinetobacter baumannii bacteremia during 11 years at an academic medical center.

BACKGROUND: In the past decade, carbapenem-resistant Acinetobacter baumannii (CRAB) has emerged as a major pathogen of serious infections in critically ill adult patients. Despite very limited antimicrobial options, clinicians have sought to reduce the mortality of patients with serious CRAB infections. To determine whether these long-term efforts effectively lessened the mortality of such patients, we investigated changes in the early mortality of adult patients with CRAB bacteremia and related clinical factors. METHODS: We reviewed clinical data from 111 adult patients with monomicrobial CRAB bacteremia admitted to an academic medical center between 2006 and 2016. RESULTS: The 14-day mortality rate from 2013 to 2016 was lower than that from 2009 to 2012 (43.4% vs. 71.1%, p = 0.01). When the clinical characteristics of adult patients with CRAB bacteremia from 2013 to 2016 were compared to those of the patients from 2009 to 2012, chronic lung disease (6.7% vs. 24.4%, p = 0.01), a recent history of mechanical ventilation (38.3% vs. 57.8%, p = 0.048), and pneumonia (48.3% vs. 68.9%, p = 0.04) were less frequent in 2013-2016, while neurological disease (43.3% vs. 22.2%, p = 0.02), central venous catheter infection (20.0% vs. 6.7%, p = 0.05), and early appropriate antimicrobial therapy (46.7% vs. 24.4%, p = 0.01) were more frequent. CONCLUSION: The 14-day mortality rate of adult patients with CRAB bacteremia was reduced during 2013-2016. This decrease was associated with early appropriate antimicrobial therapy and a lower proportion of patients with bacteremic pneumonia, which seemed to result from improved hospital infection control during that time period.

Usefulness of national respiratory virus surveillance data for clinicians who manage adult patients.

The Korean Centers for Disease Control and Prevention (KCDC) provides weekly respiratory virus (RV) surveillance reports on its website (the KCDC data). Clinicians in clinical settings wherein the use of PCR for RVs is not a routine laboratory test for adult patients with acute respiratory illness (ARI) may question the clinical utility of such a national RV surveillance dataset in predicting RV outbreaks among their adult patients. We compared the KCDC data to the RV PCR data of adult patients who visited a tertiary care center. During a period of 108 weeks, a total of 6955 (5598 pediatric and 1257 adult) patients underwent RV PCR tests for ARI; most of these tests were administered while the patients were admitted (n = 6,920; 99.5%). From the KCDC website, we collected the RV PCR test results of 22 540 patients. Three graphs of weekly positivity rates were made for adults, children, and the KCDC data per each RV, and these graphs were then compared with one another. Whereas RV outbreaks were coincident between the KCDC and the adult graph with respect to influenza virus, respiratory syncytial virus, human metapneumovirus, and human coronavirus, the same was not true for human bocavirus, parainfluenza virus, rhinovirus, and adenovirus. However, a negative predictive value of the KCDC data in the prediction of the occurrence of an outbreak in the adult graph was high for the respective eight RVs (85-100%). A national RV surveillance dataset may be useful in identifying RV outbreaks in adult patients with severe ARI.

Utility of Magnetic Resonance Imaging for Differentiating Necrotizing Fasciitis from Severe Cellulitis: A Magnetic Resonance Indicator for Necrotizing Fasciitis (MRINEC) Algorithm.

We developed a new magnetic resonance indicator for necrotizing fasciitis (MRINEC) algorithm for differentiating necrotizing fasciitis (NF) from severe cellulitis (SC). All adults with suspected NF between 2010 and 2018 in a tertiary hospital in South Korea were enrolled. Sixty-one patients were diagnosed with NF and 28 with SC. Among them, 34 with NF and 15 with SC underwent magnetic resonance imaging (MRI). The MRINEC algorithm, a two-step decision tree including T2 hyperintensity of intermuscular deep fascia and diffuse T2 hyperintensity of deep peripheral fascia, diagnosed NF with 94% sensitivity (95% confidence interval (CI), 80-99%) and 60% specificity (95% CI, 32-84%). The algorithm accurately diagnosed all 15 NF patients with a high (≥8) laboratory risk indicator for necrotizing fasciitis (LRINEC) score. Among the five patients with an intermediate (6-7) LRINEC score, sensitivity and specificity were 100% (95% CI, 78-100%) and 0% (95% CI, 0-84%), respectively. Finally, among the 29 patients with a low (≤5) LRINEC score, the algorithm had a sensitivity and specificity of 88% (95% CI, 62-98%) and 69% (95% CI, 39-91%), respectively. The MRINEC algorithm may be a useful adjuvant method for diagnosing NF, especially when NF is suspected in patients with a low LRINEC score.

Clinical and Microbiological Analysis of Risk Factors for Mortality in Patients With Carbapenem-Resistant Acinetobacter baumannii Bacteremia.

BACKGROUND: Carbapenem-resistant Acinetobacter baumannii (CRAB) infection is associated with significant mortality, causing worldwide concern, yet there are limited data on contributing microbiological factors. This study aimed to identify the clinical and microbiologic risk factors for mortality in CRAB bacteremia. METHODS: Adult patients with monomicrobial CRAB bacteremia in a 2700-bed tertiary hospital between December 2012 and December 2018 were retrospectively enrolled. Risk factors for 30-day mortality were evaluated. All isolates collected on the first day of bacteremia were subjected to colistin susceptibility testing by broth microdilution and to genotyping by multilocus sequence typing. RESULTS: A total of 164 patients were enrolled, and 90 (55%) died within 30 days. The most common genotype among the isolates was ST191 (49%), and 12 isolates (7%) were resistant to colistin. Genotype, colistin minimum inhibitory concentration, and colistin resistance were not significantly associated with mortality, in contrast to several clinical factors. In multivariable analysis, ineradicable or not-eradicated focus (adjusted odds ratio [aOR], 4.92; 95% CI, 1.95-12.42; P = .001), septic shock (aOR, 4.72; 95% CI, 2.12-10.49; P < .001), and inappropriate antimicrobial therapy (aOR, 2.54; 95% CI, 1.05-6.16; P = .04) were independent risk factors for mortality. Among antibiotic strategies, colistin combined with tigecycline or other antibiotics were significantly associated with lower mortality after adjustment for confounding factors. CONCLUSIONS: Clinical factors such as the nature of the infection source and source control, severity of bacteremia, and appropriateness of antibiotics, rather than microbiological factors, contribute to mortality in CRAB bacteremia. A specific antibiotic combination may help improve outcomes.