Epidemiology of bloodstream infections caused by Acinetobacter baumannii and impact of drug resistance to both carbapenems and ampicillin-sulbactam on clinical outcomes.

Acinetobacter baumannii has become a leading cause of bloodstream infections (BSI) in health care settings. Although the incidence of infection with carbapenem- and ampicillin-sulbactam-resistant (CASR) A. baumannii has increased, there is a scarcity of studies which investigate BSI caused by CASR A. baumannii. A retrospective cohort study was conducted on adult patients with BSI caused by A. baumannii and who were admitted to the Detroit Medical Center between January 2006 and April 2009. Medical records were queried for patients' demographics, antimicrobial exposures, comorbidities, hospital stay, and clinical outcomes. Bivariate analyses and logistic regression were employed in the study. Two hundred seventy-four patients with BSI caused by A. baumannii were included in the study: 68 (25%) caused by CASR A. baumannii and 206 (75%) caused by non-CASR A. baumannii. In multivariate analysis, factors associated with BSI caused by CASR A. baumannii included admission with a rapidly fatal condition (odds ratio [OR] = 2.83, 95% confidence interval [CI] = 1.27 to 6.32, P value = 0.01) and prior use of antimicrobials (OR = 2.83, 95% CI = 1.18 to 6.78, P value = 0.02). In-hospital mortality rates for BSI caused by CASR A. baumannii were significantly higher than those for non-CASR A. baumannii-induced BSI (43% versus 20%; OR = 3.0, 95% CI = 1.60 to 5.23, P value < 0.001). However, after adjusting for potential confounders, the association between BSI caused by CASR A. baumannii and increased risk of in-hospital mortality was not significant (OR = 1.15, 95% CI = 0.51 to 2.63, P value = 0.74). This study demonstrated that CASR A. baumannii had a distinct epidemiology compared to more susceptible A. baumannii strains; however, clinical outcomes were similar for the two groups. Admission with a rapidly fatal condition was an independent predictor for both CASR A. baumannii and in-hospital mortality.

Outbreak of colistin-resistant, carbapenem-resistant Klebsiella pneumoniae in metropolitan Detroit, Michigan.

Carbapenem-resistant Klebsiella pneumoniae has spread worldwide and throughout the United States. Colistin is used extensively to treat infections with this organism. We describe a cluster of colistin-resistant, carbapenem-resistant K. pneumoniae infection cases involving three institutions in Detroit, MI. A cluster of five cases of colistin-resistant, carbapenem-resistant K. pneumoniae was identified at Detroit Medical Center (DMC) from 27 July to 22 August 2009. Epidemiologic data were collected, and transmission opportunities were analyzed. Isolates were genotyped by using pulsed-field gel electrophoresis and repetitive extragenic palindromic PCR. Data regarding the use of colistin were obtained from pharmacy records. The index case of colistin-resistant, carbapenem-resistant K. pneumoniae was followed 20 days later by four additional cases occurring in a 6-day interval. All of the patients, at some point, had stayed at one particular institution. The mean number of opportunities for transmission between patients was 2.3 ± 0.5, and each patient had at least one opportunity for transmission with one of the other patients. Compared to 60 colistin-susceptible, carbapenem-resistant K. pneumoniae controls isolated in the previous year at DMC, case patients were significantly older (P = 0.05) and the carbapenem-resistant K. pneumoniae organisms isolated from them displayed much higher MICs to imipenem (P < 0.001). Colistin use was not enhanced in the months preceding the outbreak. Genotyping revealed two closely related clones. This report of a colistin-resistant, carbapenem-resistant K. pneumoniae outbreak is strongly linked to patient-to-patient transmission. Controlling the spread and novel emergence of bacteria with this phenotype is of paramount importance.

Butane Hash Oil Burns Associated with Marijuana Liberalization in Colorado.

Butane hash oil (BHO), also known as "amber," "dab," "glass," "honey," "shatter," or "wax," is a potent marijuana concentrate, containing up to 90 % tetrahydrocannabinol (THC). BHO is easily manufactured using highly volatile butane as a solvent. Our objective was to characterize hydrocarbon burns associated with BHO manufacture in Colorado. This was a cross-sectional study utilizing the National Burn Repository to capture all hydrocarbon burns reported to the local burn center from January 1st, 2008, through August 31st, 2014. We abstracted demographic and clinical variables from medical records for patients admitted for hydrocarbon burns associated with butane hash oil extraction. Twenty-nine cases of BHO burns were admitted to the local burn center during the study period. Zero cases presented prior to medical liberalization, 19 (61.3 %) during medical liberalization (Oct 2009-Dec 2013), and 12 (38.7 %) in 2014 since legalization. The majority of cases were Caucasian (72.4 %) males (89.7 %). Median age was 26 (range 15-58). The median total-body-surface-area (TBSA) burn size was 10 % (TBSA range 1-90 %). Median length of hospital admission was 10 days. Six required intubation for airway protection (21 %). Nineteen required skin grafting, eight wound care only, one required surgical fracture repair, and one required surgical debridement. Hydrocarbon burns associated with hash oil production have increased since the liberalization of marijuana policy in Colorado. A combination of public health messaging, standardization of manufacturing processes, and worker safety regulations are needed to decrease the risks associated with BHO production.

Outcomes and genetic relatedness of carbapenem-resistant enterobacteriaceae at Detroit medical center.

BACKGROUND: Carbapenem-resistant Enterobacteriaceae (CRE) are rapidly emerging in hospitals in the United States and are posing a significant threat. To better understand the transmission dynamics and the acquisition of resistant strains, a thorough analysis of epidemiologic and molecular characteristics was performed. METHODS: CRE isolated at Detroit Medical Center were analyzed from September 2008 to September 2009. bla(KPC) genes were investigated by polymerase chain reaction (PCR), and repetitive extragenic palindromic PCR (rep-PCR) was used to determine genetic similarity among strains. Epidemiologic and outcomes analyses were performed. RESULTS: Ninety-two unique patient CRE isolates were recovered. Sixty-eight strains (74%) were Klebsiella pneumoniae, 7 were Klebsiella oxytoca, 15 were Enterobacter species, and 2 were Escherichia coli. Fifteen isolates (16%) were resistant to colistin, 14 (16%) were resistant to tigecycline, and 2 were resistant to all antimicrobials tested. The mean ± standard deviation age of patients was 63 ± 2 years. Sixty patients (68%) were admitted to the hospital from long-term care facilities. Only 70% of patients received effective antimicrobial therapy when infection was suspected, with a mean time to appropriate therapy of 120 ± 23 hours following sample culturing. The mean length of hospitalization after sample culturing was 18.6 ± 2.5 days. Of 57 inpatients, 18 (32%) died in the hospital. Independent predictors for mortality were intensive care unit stay (odds ratio [OR], 15.8; P = .003) and co-colonization with CRE and either Acinetobacter baumannii or Pseudomonas aeruginosa (OR, 17.2; P = .006). Among K. pneumoniae CRE, rep-PCR revealed 2 genetically related strains that comprised 70% and 20% of isolates, respectively. CONCLUSIONS: In this large U.S. cohort of patients with CRE infection, which reflects the modern continuum of medical care, co-colonization with CRE and A. baumannii or P. aeruginosa was associated with increased mortality. Two predominant clones of K. pneumoniae accounted for the majority of cases of CRE infection.