High Pitt Bacteremia Score Research Articles

Should we treat patients with only one set of positive blood cultures for extensively drug-resistant Acinetobacter baumannii the same as multiple sets?

Acinetobacter species are not considered skin commensals and under-treatment is an overriding concern when caring for critically-ill patients who are mostly at risk of extensively drug-resistant Acinetobacter baumannii (XDRAB) infections. Hence even a single blood culture yielding XDRAB will tend to prompt intervention. However, field observations suggest that patients with single-positive blood cultures had milder disease and were more likely to be recruited in interventional studies than those with multiple-positive blood cultures, yet no distinction is made in current clinical or trial recruitment practices. To our knowledge, this is the first study to compare the clinical characteristics and outcomes of patients with single-positive versus multiple-positive blood cultures for XDRAB. In this multicenter prospective cohort study of XDRAB bacteremic patients from July 2010 to June 2015, only patients with at least two simultaneously drawn blood cultures were included. The patients were classified as having single-positive or multiple-positive blood cultures according to the number of positive blood cultures yielding XDRAB. The primary end-point was the 28-day mortality. Of a total of 155 patients enrolled, 69 had a single-positive and 86 had multiple-positive blood cultures. Leukopenia (37.2% vs. 16.2%; P = 0.004), thrombocytopenia (56.0% vs. 26.5%; P < 0.001), higher Pitt bacteremia scores (6.6 vs. 5.5, P = 0.03) and higher 28-day mortality rates (70.9% vs. 43.5%; P = 0.001) distinguished patients with multiple-positive from those with single-positive cultures. Multivariate logistic regression showed that multi-positivity independently predicted 28-day mortality (adjusted odds ratio, 2.34; 95% confidence interval (CI), 1.03–5.28; P = 0.04) and the Cox regression confirmed that multi-positivity (adjusted hazard ratio, 1.80; 95% CI, 1.13–2.85; P = 0.01) predicted rapid mortality. Patients with multiple versus single positive blood cultures yielding XDRAB had greater morbidity and mortality. Investigators and clinicians should be aware that the blood culture positivity rate impacts outcomes of XDRAB bacteremia.

Vancomycin-resistant Enterococcal Bloodstream Infections in Hematopoietic Stem Cell Transplant Recipients and Patients with Hematologic Malignancies: Impact of Daptomycin MICs of 3 to 4 mg/L

PurposeCase reports of treatment failure with standard-dose daptomycin (6 mg/kg) have recently surfaced in vancomycin-resistant Enterococcus (VRE) bloodstream infection (BSI) episodes with daptomycin MICs of 3 to 4 mg/L. The clinical implications of daptomycin MICs of 3 to 4 mg/L in VRE BSIs have not been elucidated. MethodsWe performed a single institutional retrospective analysis of adult stem cell transplant recipients and patients with hematologic malignancies diagnosed with VRE BSI from 2006 to 2014 and compared outcomes between those with daptomycin MICs of 3 to 4 mg/L those with 2 mg/L, as determined by Etest. FindingsForty-two daptomycin-treated VRE BSI episodes, all due to Enterococcus faecium were identified; 19 episodes with daptomycin MICs of 3 to 4 mg/L and 23 episodes with a daptomycin MIC of 2 mg/L. Patients in the higher daptomycin MIC group were more likely to be male, to be stem cell transplant recipients, and to have received high-dose daptomycin treatment (>6 mg/kg). In unadjusted analyses, microbiological failure in the daptomycin MICs 3 to 4 mg/L versus 2 mg/L groups (odds ratio = 1.79, 95% CI, 0.52–6.11; P = 0.35), the median duration of bacteremia (4 days in daptomycin MICs 3–4 mg/L vs 3 days in daptomycin MIC 2 mg/L; P = 0.18) and all-cause 30-day mortality (21% in daptomycin MICs 3–4 mg/L vs 35% in daptomycin MIC 2 mg/L group; P = 0.49) were not different. In adjusted analyses, the association between higher Pitt bacteremia scores and all-cause 30-day mortality was statistically significant (P = 0.0006), whereas the association between daptomycin MICs of 3 to 4 mg/L and all-cause 30-day mortality approached statistical significance (P = 0.06). ImplicationsDuration of bacteremia and microbiological failure rates did not differ by daptomycin MICs in VRE BSI episodes in our patients, composed of adult stem cell transplant recipients and patients with hematologic malignancies. There was a nonsignificant trend in multivariable analysis suggesting that all-cause 30-day mortality was lower in patients whose VRE bloodstream isolates were with daptomycin MICs of 3 to 4 mg/L.

Empirical third-generation cephalosporin therapy for adults with community-onset Enterobacteriaceae bacteraemia: Impact of revised CLSI breakpoints

Third-generation cephalosporins (3GCs) [ceftriaxone (CRO) and cefotaxime (CTX)] have remarkable potency against Enterobacteriaceae and are commonly prescribed for the treatment of community-onset bacteraemia. However, clinical evidence supporting the updated interpretive criteria of the Clinical and Laboratory Standards Institute (CLSI) is limited. Adults with community-onset monomicrobial Enterobacteriaceae bacteraemia treated empirically with CRO or CTX were recruited. Clinical information was collected from medical records and CTX MICs were determined using the broth microdilution method. Eligible patients (n=409) were categorised into de-escalation (260; 63.6%), no switch (115; 28.1%) and escalation (34; 8.3%) groups according to the type of definitive antibiotics. Multivariate regression revealed five independent predictors of 28-day mortality: fatal co-morbidities based on McCabe classification [odds ratio (OR)=19.96; P<0.001]; high Pitt bacteraemia score (≥4) at bacteraemia onset (OR=13.91; P<0.001); bacteraemia because of pneumonia (OR=5.45; P=0.007); de-escalation after empirical therapy (OR=0.28; P=0.03); and isolates with a CTX MIC≤1mg/L (OR=0.17; P=0.02). Of note, isolates with a CTX MIC≤8mg/L (indicated as susceptible by previous CLSI breakpoints) were not associated with mortality. Furthermore, clinical failure and 28-day mortality rates had a tendency to increase with increasing CTX MIC (γ=1.00; P=0.01). Conclusively, focusing on patients with community-onset Enterobacteriaceae bacteraemia receiving empirical 3GC therapy, the present study provides clinically critical evidence to validate the proposed reduction in the susceptibility breakpoint of CTX to MIC≤1mg/L.

Time-to-positivity of blood culture: An independent prognostic factor of monomicrobial Pseudomonas aeruginosa bacteremia.

Pseudomonas aeruginosa bacteremia is an important cause of nosocomial infections with high morbidity and mortality. Time-to-positivity (TTP) of blood cultures is considered to be a predictor of the clinical outcome for bacteremia. The aim of the study is to investigate the relationship between TTP and clinical outcomes in patients with monomicrobial P. aeruginosa bacteremia. From January 2013 to June 2014, a retrospective cohort study was conducted in a 1200-bed tertiary care hospital. The cases of monomicrobial P. aeruginosa bacteremia were studied. TTP and clinical parameters were determined and analyzed. In 139 cases of P. aeruginosa bacteremia, TTP ≤ 13 hours was associated with higher Pitt bacteremia scores (5.3±4.2 vs. 2.3±2.8, p<0.001), severe sepsis (66.1% vs. 35.0%, p<0.001), higher 30-day mortality rate (54.2% vs. 15.0%, p<0.001), longer hospitalization in the survivors (25.6±48.5 days vs. 16.3±15.3 days, p=0.16), and more admission to intensive care unit (27.2% vs. 16.3%, p=0.14). Risk factors for 30-day mortality in the univariate analysis included corticosteroid exposure, primary bacteremia, concurrent pneumonia, a high Pitt bacteremia score, severe sepsis, and TTP ≤ 13 hours. In the multivariate analysis, primary bacteremia, a pulmonary origin of bacteremia, severe sepsis, and TTP ≤ 13 hours were independent risk factors for 30-day mortality. In cases of monomicrobial P. aeruginosa bacteremia, a short TTP (≤ 13 hours) provides prognostic information, in addition to clinical parameters.

Central line-associated bloodstream infections among critically-ill patients in the era of bundle care.

Patients admitted to intensive care units (ICUs) are at high risk for central line-associated bloodstream infections (CLABSIs). Bundle care has been documented to reduce CLABSI rates in Western countries, however, few reports were from Asian countries and the differences in the epidemiology or outcomes of critically-ill patients with CLABSIs after implementation of bundle care remain unknown. We aimed to evaluate the incidence, microbiological characteristics, and factors associated with mortality in critically-ill patients after implementation of bundle care. Prospective surveillance was performed on patients admitted to ICUs at the National Taiwan University Hospital, Taipei, Taiwan from January 2012 to June 2013. The demographic, microbiological, and clinical data of patients who developed CLABSI according to the National Healthcare Safety Network definition were reviewed. A total of 181 episodes of CLABSI were assessed in 156 patients over 46,020 central-catheter days. The incidence of CLABSI was 3.93 per 1000 central-catheter days. The predominant causative microorganisms isolated from CLABSI episodes were Gram-negative bacteria (39.2%), followed by Gram-positive bacteria (33.2%) and Candida spp. (27.6%). Median time from insertion of a central catheter to occurrence of CLABSI was 8 days. In multivariate analysis, the independent factors associated with mortality were higher Pitt bacteremia score [odds ratio (OR) 1.41; 95% confidence interval (CI) 1.18-1.68] and longer interval between onset of CLABSIs and catheter removal (OR 1.10; 95% CI 1.02-1.20), respectively. In institutions with a high proportion of CLABSI caused by Gram-negative bacteria, severity of bacteremia and delay in catheter removal were significant factors associated with mortality.

Clinical and microbiologic analysis of the risk factors for mortality in patients with heterogeneous vancomycin-intermediate Staphylococcus aureus bacteremia.

The prevalence of the heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) phenotype among methicillin-resistant S. aureus (MRSA) blood isolates can reach 38%. hVISA bacteremia is known to be associated with vancomycin treatment failure, including persistent bacteremia. We conducted this study to evaluate risk factors for 12-week mortality in patients with hVISA bacteremia through a detailed clinical and microbiological analysis of a prospective cohort of patients with S. aureus bacteremia. All isolates were collected on the first day of bacteremia and subjected to population analysis profiling for hVISA detection, genotyping, and PCR analysis for 39 virulence factors. Of 382 patient with MRSA bacteremia, 121 (32%) had hVISA bacteremia. Deceased patients were more likely to have hematologic malignancy (P = 0.033), ultimately or rapidly fatal disease (P = 0.007), and a higher Pitt bacteremia score (P = 0.010) than surviving patients. The sequence type 239 (ST239) clonal type and definitive linezolid treatment were associated with a trend toward reduced mortality (P = 0.061 and 0.072, respectively), but a high vancomycin MIC (≥2 mg/liter) was not associated with increased mortality (P = 0.368). In a multivariate analysis, ultimately or rapidly fatal disease (adjusted odds ratio [aOR], 2.80; 95% confidence interval [CI], 1.14 to 6.85) and a high Pitt bacteremia score (aOR, 1.26; 95% CI, 1.07 to 1.48) were independent risk factors for mortality. Hematologic malignancy was associated with a trend toward increased mortality (P = 0.094), and ST239 was associated with a trend toward reduced mortality (P = 0.095). Our study suggests that ST239 hVISA is a possible predictor of survival in hVISA bacteremia.

Clinical Features and Treatment Outcomes of Bloodstream Infections Caused by Extended-Spectrum β-Lactamase-Producing Escherichia coli Sequence Type 131.

Despite the remarkable emergence of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli sequence type 131 (ST131), the clinical features and outcomes of infections caused by ST131 remain poorly described. From 2011 to 2012, we collected ESBL-producing E. coli isolates from patients with bloodstream infections in 13 hospitals in Korea and compared clinical characteristics and outcomes between ST131 and non-ST131 clones. Of the 110 ESBL-producing isolates, the most common ST was ST131 (30.9%). Multivariate analysis showed that recent operation was the only variable associated with the ST131 clone; other comorbid conditions and clinical features were similar between ST131 and non-ST131 clones. CTX-M-14 and CTX-M-15 were the predominant types of ESBLs, and CTX-M-15 was significantly associated with ST131. The rate of nonsusceptibility to ciprofloxacin was higher in ST131 than in non-ST131 clones (94.1% vs. 75.0%). No significant differences in 30-day mortality rates were found between ST131 and non-ST131 clones. Multivariate analysis revealed that older age (odds ratio [OR]=5.39, 95% confidence interval [CI] 1.22-23.89; p=0.027), nosocomial infection (OR=4.81, 95% CI 1.15-20.15; p=0.032), and higher Pitt bacteremia score (OR=7.26, 95% CI 1.41-37.42; p=0.018) were independent risk factors for 30-day mortality. The ESBL-producing E. coli ST131 clone has emerged and disseminated in Korea. Our findings reveal similarities in clinical and demographic characteristics between ST131 and non-ST131 clones. Although a more resistant profile has been detected in ST131, patients with the ST131 clone did not exhibit a higher mortality rate.

Epidemiology and microbiology of nosocomial bloodstream infections: analysis of 482 cases from a retrospective surveillance study.

In many traditional Chinese medicine (TCM) hospitals, most patients are elderly with chronic diseases. Nosocomial bloodstream infections (nBSIs) are an important cause of morbidity and mortality. A retrospective surveillance study was performed to examine the epidemiology and microbiology of nBSIs in a TCM hospital from 2009 to 2011. A total of 482 patients with nBSIs were included in the study period. The incidence rate was 5.7/1000 admissions. Escherichia coli (25.5%) was the most common Gram-negative and coagulase-negative staphylococcus (CoNS) (14.1%) was the most common Gram-positive organism isolated. One-third of the E. coli and Klebsiella pneumoniae isolated from the nBSIs were the third-generation cephalosporin-resistant. Half of the Acinetobacter species isolates were resistant to imipenem. Of all the CoNS isolates, 90.7% were resistant to methicillin. Carbapenems and glycopeptide were the most frequently used for nBSI therapy. Only about one-third of patients (157/482) received appropriate empirical therapy. Septic shock, hemodialysis, Pitt bacteremia score >4, urinary tract infection, and appropriate empirical therapy were most strongly associated with 28-d mortality. The incidence of nBSIs was low in the TCM hospital but the proportion of nBSIs due to antibiotic-resistant organisms was high. A high Pitt bacteremia score was one of the most important risk factors for mortality in nBSIs. Therefore, the implementation of appropriate empirical therapy is crucial to improve the clinical outcome of nBSIs.

Group B streptococcal bacteremia in non-pregnant adults: results from two Korean centers.

Patients with liver cirrhosis (LC) have impaired immunity and are, thus, predisposed to infection. Few studies have attempted to evaluate group B streptococcal (GBS) bacteremia in LC patients. A retrospective study of patients with GBS bacteremia was performed at the Dongguk University Ilsan Hospital and National Health Insurance Service Ilsan Hospital over a 13-year period (October 2000 to July 2013). During the study period, 97 patients with GBS bacteremia were enrolled. The median age of the patients was 67 years and 54% were men. Among them, 23 (24%) patients were classified as LC patients. The 30-day mortality rate of LC patients was significantly higher than that of patients with other diseases (26% vs. 8%, p = 0.03). The multivariate analysis indicated that LC was associated with an increased risk of 30-day mortality [hazard ratio (HR) 5.0; 95% confidence interval (CI) 1.53-16.3; p = 0.008], as well as age (HR 1.07; 95% CI 1.03-1.13; p = 0.02) and high Pitt bacteremia score (HR 1.23; 95% CI 1.02-1.46; p = 0.03). The probability of survival at day 30 was significantly different for the Child-Pugh class C and the Child-Pugh classes A or B (44% vs. 93%, respectively; p = 0.01 by the log-rank test). The mortality rates of LC patients with GBS bacteremia were significantly higher than those of patients with other diseases. The severity of hepatic dysfunction plays an important role in the development of adverse events. Cirrhosis-specific scores such as the Child-Pugh class might be useful for predicting the prognosis of GBS bacteremia in LC patients.

Comparison of colistin–carbapenem, colistin–sulbactam, and colistin plus other antibacterial agents for the treatment of extremely drug-resistant Acinetobacter baumannii bloodstream infections

The purpose of this investigation was to compare the efficacy of colistin-based therapies in extremely drug-resistant Acinetobacter spp. bloodstream infections (XDR-ABSI). A retrospective study was conducted in 27 tertiary-care centers from January 2009 to August 2012. The primary end-point was 14-day survival, and the secondary end-points were clinical and microbiological outcomes. Thirty-six and 214 patients [102 (47.7%): colistin-carbapenem (CC), 69 (32.2%): colistin-sulbactam (CS), and 43 (20.1%: tigecycline): colistin with other agent (CO)] received colistin monotherapy and colistin-based combinations, respectively. Rates of complete response/cure and 14-day survival were relatively higher, and microbiological eradication was significantly higher in the combination group. Also, the in-hospital mortality rate was significantly lower in the combination group. No significant difference was found in the clinical (p = 0.97) and microbiological (p = 0.92) outcomes and 14-day survival rates (p = 0.79) between the three combination groups. Neither the timing of initial effective treatment nor the presence of any concomitant infection was significant between the three groups (p > 0.05) and also for 14-day survival (p > 0.05). Higher Pitt bacteremia score (PBS), Acute Physiology and Chronic Health Evaluation II (APACHE II) score, Charlson comorbidity index (CCI), and prolonged hospital and intensive care unit (ICU) stay before XDR-ABSI were significant risk factors for 14-day mortality (p = 0.02, p = 0.0001, p = 0.0001, p = 0.02, and p = 0.01, respectively). In the multivariable analysis, PBS, age, and duration of ICU stay were independent risk factors for 14-day mortality (p < 0.0001, p < 0.0001, and p = 0.001, respectively). Colistin-based combination therapy resulted in significantly higher microbiological eradication rates, relatively higher cure and 14-day survival rates, and lower in-hospital mortality compared to colistin monotherapy. CC, CS, and CO combinations for XDR-ABSI did not reveal significant differences with respect to 14-day survival and clinical or microbiological outcome before and after propensity score matching (PSM). PBS, age, and length of ICU stay were independent risk factors for 14-day mortality.

P009: Epidemiology, microbiology and outcome of community-οnset gram-negative bacteremias in a Greek University Hospital

Among 145 patients with gram-negative COB, 83 (57.2%) had HCAB and 62 (42.8%) had CAB. The frequency of malignant tumors, renal insufficiency and dementia was higher in patients with HCAB than with CAB. In both groups Escherichia coli was the mostcommon causative agent but the prevalence of Klebsiella pneumoniae in HCAB was significantly higher than CAB (19.3% vs. 4.8%). Patients with HCAB had higher Charlson score and higher Pitt bacteremia score, less frequent administration of appropriate empirical antibiotic treatment and higher probability of death than patients with CAB. The antimicrobial resistance in HCAB aι CAB patients respectively, was found 27/83 (32.5%) vs. 4/62 (6.5%) (P<.001) to third-generation cephalosporins (3GC), 22/83 (26.5%) vs. 7/62 (11.3%) (P=.021) to aminoglycosides, 29/83 (34.9%) vs. 9/62 (14.5%) (P=.005) to quinolones. Bacteria that produced ESBL were 16/76 (21.1%) vs. 2/59 (3.4%) (P=.003), and carbapenem-resistant were 10/83 (12.0%) vs. 2/62 (3.2%) (P=.056) in HCAB aι CAB patients respectively Conclusion There are significant differences in the severity of underly- ing diseases, causative pathogens, antibiotic resistance, outcome and treatment between the two groups. In our region 3GC, aminoglycosides or fluoroquinolones are pro- posed as appropriate empirical treatment for patients with CAB, whereas in patients with HCAB carbapenems should be the initial therapy. Disclosure of interest None declared.

Outcomes and risk factors for mortality in community-onset bacteremia caused by extended-spectrum beta-lactamase-producing Escherichia coli, with a special emphasis on antimicrobial therapy

Although extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli has emerged as a significant pathogen, there is little information regarding treatment outcomes in community-onset bacteremia due to ESBL E. coli. The purpose of this study was to evaluate treatment outcomes of community-onset bacteremia caused by ESBL-producing E. coli and the factors associated with mortality. A retrospective cohort study was performed, including 92 adult patients with community-onset bacteremia caused by ESBL-producing E. coli. The 30-day mortality rate was 10.9% (10/92). Independent risk factors for mortality were underlying liver disease and severity of illness (e.g., high Pitt bacteremia score, the presence of severe sepsis or septic shock; p < 0.05). Mortality in patients receiving inappropriate initial antimicrobial therapy was not significantly higher than mortality in those receiving appropriate empirical antimicrobial therapy (10.9 vs 10.7%; p = 0.975), if antimicrobial therapy was adjusted appropriately according to susceptibility results. Carbapenems, piperacillin/tazobactam, fluoroquinolones, and amikacin were the most effective antibiotics for community-onset bacteremia caused by ESBL-producing E. coli, although susceptibility profiles confirmed that alternatives to carbapenems are limited. Of 68 isolates in which the ESBLs and their molecular relationships were studied, all isolates produced ESBLs from the CTX-M family (CTX-M-14, 30 isolates; CTX-M-15, 22; and other CTX-M, 16). In patients with community-onset bacteremia caused by ESBL-producing E. coli, severe sepsis and underlying liver disease were significantly associated with mortality, and a delay in appropriate antimicrobial therapy was not associated with a higher mortality if therapy was adjusted appropriately according to the susceptibility results.

Impact of a computerized alert system for bacteremia notification on the appropriate antibiotic treatment of Staphylococcus aureus bloodstream infections

A computerized alert system (CAS) has been introduced to notify bacteremia in real time. We evaluated the impact of the CAS on the administration of appropriate antibiotics in patients with Staphylococcus aureus bloodstream infections (BSIs). We retrospectively reviewed the medical records of patients with S. aureus BSI for each 1-year control and intervention periods, before and after the implementation of the CAS. The proportions of appropriate antibiotic treatment were compared between the control and intervention periods. The 30-day mortality of S. aureus bacteremia was also assessed in the study population. A total of 313 patients were included in the study. Appropriate antibiotics were initiated 7 h earlier in the intervention period (mean time, 13.5 h vs. 20.0 h; p = 0.136). The administration of appropriate antibiotics within the 24 h after blood acquisition was similar between the two periods, but this significantly increased from 3.3% in the control period to 10.6% in the intervention during the 24-36 h interval (p = 0.012). In the subgroup analysis, similar trends were observed in patients with methicillin-resistant isolates (6.7% vs. 18.2%; p = 0.032) and hospital-onset infection (3.5% vs. 17.1 %; p = 0.004). The independent risk factors for 30-day mortality of S. aureus bacteremia were age, a high Pitt bacteremia score, an increased Charlson's weighted index of comorbidity, and hospital-onset infection, although the appropriateness of antibiotic therapy within 36 h and the CAS were not identified as predictors. The CAS increased the proportion of appropriate antimicrobial therapy during the 24-36 h interval after bacteremia onset in patients with S. aureus BSIs.

Impact of acute kidney injury on mortality and medical costs in patients with meticillin-resistant Staphylococcus aureus bacteraemia: a retrospective, multicentre observational study

Despite the frequent occurrence of acute kidney injury (AKI) associated with meticillin-resistant Staphylococcus aureus (MRSA) infection during treatment, the adverse impact of renal injury on clinical and economic outcomes has not been evaluated. To study the clinical and economic burdens of MRSA bacteraemia and the impact of AKI occurring during treatment on outcomes. Medical records of patients hospitalized for MRSA bacteraemia between March 2010 and February 2011 in eight hospitals in Korea were reviewed retrospectively to evaluate the risk factors for AKI and mortality. Direct medical costs per patient of MRSA bacteraemia during treatment were estimated from the medical resources consumed. In all, 335 patients were identified to have MRSA bacteraemia. AKI occurred in 135 patients (40.3%) during first-line antibiotic therapy. Independent risk factors for AKI were male sex, underlying renal disease, intra-abdominal and central venous catheter infection, and increase in Pitt bacteraemia score. Seventy-seven (23.0%) patients died during the study period. Underlying solid tumour, high Pitt bacteraemia score, and occurrence of AKI were independent risk factors for mortality. The mean total medical cost per MRSA patient was estimated as South Korean Won 5,435,361 (US$4,906), and occurrence of AKI and ICU admission were identified as independent predictors of increased direct medical costs. Compared with patients who retained their baseline renal function, patients with AKI had a 45% increase in medical costs. Patients who developed AKI showed significantly higher mortality rate andgreater direct medical costs compared with patients who retained baseline renal function.

Clinical impact of inappropriate initial antimicrobial therapy on outcome in bacteremic biliary tract infections

The marked increase in the incidence of biliary tract infections due to antimicrobial-resistant pathogens in recent years is of great concern, as patients infected by these isolates might initially receive antibiotics ineffective against the responsible pathogens. A retrospective cohort study including 556 episodes of bacteremic biliary tract infection was designed to evaluate the impact of inappropriate initial antimicrobial therapy on the clinical outcomes of patients with biliary tract infections. Of 556 episodes, 257 (46.2%) received inappropriate initial antimicrobial therapy. Although Escherichia coli and Klebsiella species are the most common pathogens, the pathogens that were most frequently associated with inappropriate therapy were Pseudomonas aeruginosa and Enterococcus spp. In multivariable analysis, inappropriate initial antimicrobial therapy was found to be independently associated with increased mortality (odds ratio (OR) 2.25, 95% confidence interval (CI) 1.13-4.48; p = 0.021), along with pancreaticobiliary tract cancer, liver cirrhosis, Enterobacter infection, and a high Pitt bacteremia score (All p < 0.05). Subgroup multivariate analyses showed that inappropriate initial therapy was not a significant factor associated with mortality in cases where therapeutic decompression or drainage procedures were employed (OR 1.24, 95% CI 0.43-3.54; p = 0.691) or in cases with appropriate definitive antimicrobial therapy (OR 1.61, 95% CI 0.69-3.72; p = 0.270) after adjustment for other variables. Our findings suggest that the administration of inappropriate initial antimicrobial therapy might be associated with an adverse outcome in patients experiencing bacteremic biliary tract infections, and that the impact of inappropriate therapy on the outcome may be dependent on therapeutic drainage and appropriate definitive antimicrobial therapy.

Differences in characteristics between healthcare-associated and community-acquired infection in community-onset Klebsiella pneumoniae bloodstream infection in Korea

BackgroundHealthcare-associated (HCA) infection has emerged as a new epidemiological category. The aim of this study was to evaluate the impact of HCA infection on mortality in community-onset Klebsiella pneumoniae bloodstream infection (KpBSI).MethodsWe conducted a retrospective study in two tertiary-care hospitals over a 6-year period. All adult patients with KpBSI within 48 hours of admission were enrolled. We compared the clinical characteristics of HCA and community-acquired (CA) infection, and analyzed risk factors for mortality in patients with community-onset KpBSI.ResultsOf 553 patients with community-onset KpBSI, 313 (57%) were classified as HCA- KpBSI and 240 (43%) as CA-KpBSI. In patients with HCA-KpBSI, the severity of the underlying diseases was higher than in patients with CA-KpBSI. Overall the most common site of infection was the pancreatobiliary tract. Liver abscess was more common in CA-KpBSI, whereas peritonitis and primary bacteremia were more common in HCA-KpBSI. Isolates not susceptible to extended-spectrum cephalosporin were more common in HCA- KpBSI than in CA-KpBSI (9% [29/313] vs. 3% [8/240]; p = 0.006). Overall 30-day mortality rate was significantly higher in HCA-KpBSI than in CA-KpBSI (22% [70/313] vs. 11% [27/240]; p = 0.001). In multivariate analysis, high Charlson’s weighted index of co-morbidity, high Pitt bacteremia score, neutropenia, polymicrobial infection and inappropriate empirical antimicrobial therapy were significant risk factors for 30-day mortality.ConclusionsHCA-KpBSI in community-onset KpBSI has distinctive characteristics and has a poorer prognosis than CA-KpBSI, but HCA infection was not an independent risk factor for 30-day mortality.

Stenotrophomonas maltophilia bloodstream infection: Comparison between community-onset and hospital-acquired infections

Stenotrophomonas maltophilia has been recognized as an important nosocomial pathogen, but few reports have discussed S. maltophilia infection in the community settings. This study aimed to reveal characteristics of patients with community-onset S. maltophilia bloodstream infection (SMBSI), to specify the subgroup of healthcare-associated (HCA) infection in the community-onset group and to compare them with hospital-acquired (HA) SMBSI patients. Medical charts of adult patients with SMBSI presenting to a medical center in southern Taiwan from May 2008 to October 2011 were reviewed and analyzed retrospectively. Among 153 patients, we observed a high percentage (38.6%) of SMBSI to be community onset. Among community-onset SMBSI, 45.8% were community-acquired (CA) and 54.2% were HCA. The crude mortality rates were 11.1%, 18.8%, and 60.6% in the CA, HCA, and HA groups, respectively. Structural/mechanical abnormalities were observed in 32.7% of all cases, and 60% of those were related to malignancy. Independent risk factors for mortality in community-onset SMBSI were liver cirrhosis, liver metastasis, and a high Pitt bacteremia score, whereas structural/mechanical abnormalities and a high Pitt bacteremia score related to increased mortality in HA SMBSI. Community-onset S. maltophilia infection deserves attention. Patients with community-onset SMBSI have reduced disease severity and lower mortality rate when compared to HA SMBSI. Underlying structural/mechanical abnormalities, especially those caused by malignancies, are common in SMBSI cases and should be investigated when bacteremia occurs.

Discrepancy between effects of carbapenems and flomoxef in treating nosocomial hemodialysis access-related bacteremia secondary to extended spectrum beta-lactamase producing klebsiella pneumoniaein patients on maintenance hemodialysis

BackgroundHemodialysis (HD) patients are susceptible to extended spectrum beta-lactamase (ESBL)-producing bacterial infections. Because the optimal treatment and clinical significance of ESBL-producing Klebsiella pneumoniae (ESBL-Kp) HD access-related bacteremia remain unclear, we conducted this retrospective study to determine the clinical outcomes of patients treated with either flomoxef or a carbapenem.MethodsThe eligibility criterion was fistula or graft- or catheter- related ESBL-Kp bacteremia in patients on maintenance HD. The clinical characteristics and antibiotic management were analyzed. Outcome was determined by mortality resulting from bacteremia during the 14‐day period after the first positive blood culture for flomoxef-susceptible ESBL-Kp.ResultsThe 57 patients studied were predominantly elderly, malnourished, with a history of severe illnesses and broad-spectrum antibiotic use before the onset of bacteremia, and with severe septicemia as determined by the Pitt bacteremia score (PBS). The study population comprised 7 fistula, 8 graft, and 42 HD catheter-related bacteremia (CRB) cases, and the mortality rate was high (36/57, 63.2%) in these 57 patients. Of 42 patients with CRB, those in the deceased group (27/42, 64.3%) had significantly lower levels of serum albumin, longer prior hospital stay and duration of catheter-dependent HD, and higher PBS than patients in the survived group. Failure to receive effective antibiotics (flomoxef or a carbapenem) within 5 days after onset of bacteremia and treatment with flomoxef both significantly contributed to higher mortality. Multivariate analyses revealed that flomoxef use, PBS, and catheter-dependent HD >30 days were independently associated with increased mortality (OR, 3.52; 95% CI, 1.19–58.17, OR, 2.92; 95% CI, 1.36–6.26 and OR, 5.73; 95% CI, 1.21–63.2, respectively).ConclusionsConsidering the high mortality rate, ESBL-Kp should be recognized as a possible pathogen in patients on maintenance HD at high risk of acquiring HD access infections associated with ESBL-producing bacteria. Carbapenems rather than flomoxef should be the therapy of choice in these critically vulnerable patients.

Clinical characteristics and prognostic factors of Acinetobacter nosocomialis bacteraemia in patients with solid tumours

The clinical characteristics and risk factors for 28-day mortality in 120 patients with solid tumours with Acinetobacter nosocomialis bacteraemia were retrospectively analysed. Eighty-one patients (67.5%) had advanced-stage cancer. Most of the bacteraemia (37.5%) did not have an identified source. The bacteraemia episodes developed at a median of 15 days after hospitalization, and most during a non-neutropenic period (97.5%). Although only half of the patients received appropriate antimicrobial therapy, the mortality was relatively low (11.7%). High Pitt bacteraemia score and receipt of chemotherapy within the month before bacteraemia onset were independently associated with 28-day mortality.

Frequent detection of plasmid-mediated quinolone resistance (qnr) genes in multidrug-resistant Enterobacteriaceae blood isolates, Hong Kong

Plasmid-mediated quinolone resistance (qnr) genes confer low-level resistance but provide background for selection of highly-resistant strains. We investigated their prevalence and significance in clinical Enterobacteriaceae bacteremic isolates in Hong Kong. A prospective, hospital-based study was conducted (January 2008 to March 2009). Consecutive, non-duplicate blood isolates of extended-spectrum-β-lactamase (ESBL) and/or plasmid-mediated AmpC (PMAmpC) β-lactamase-producing Enterobacteriaceae were collected and subjected to qnr genes detection using multiplex PCR. Direct sequencing was performed to characterize the qnr and the co-existing bla genes. Clinical and microbiological variables, including antimicrobial resistance profiles, were compared between infections by 'qnr-positive' and 'qnr-negative' Enterobacteriaceae. Altogether 199 ESBL/PMAmpC-producing Enterobacteriaceae isolates were studied. qnr genes were detected in 20 % (qnrB, n = 24; qnrS, n = 16; qnrA, n = 0), of which 85% were Klebsiella spp. There was a strong association with PMAmpC genes (qnrB and DHA-1; p < 0.001). 'qnr-positive' isolates were more commonly hospital-acquired (60.0% vs 35.8%; adjusted OR 2.68, 95%CI 1.32-5.46) and multidrug-resistant (e.g. amoxicillin-clavulanate 90-100%, piperacillin-tazobactam 40-57%, ceftazidime 53-78%; sulfamethoxazole/trimethoprim 60-70%; ciprofloxacin 53-65%, levofloxacin 35-48%). Patients with 'qnr-positive' Enterobacteriaceae bacteremia had a higher 30-day mortality (45% vs 22%, p = 0.003). High Pitt bacteremia score, development of pneumonia, and failure to receive susceptible fluoroquinolone (adjusted HR 4.27; 95%CI 1.45-12.61) or carbapenem (adjusted HR 3.04; 95%CI 1.49-6.20) treatment were independent factors associated with death. A high proportion of ESBL/PMAmpC-producing Enterobacteriaceae (typically Klebsiella) bacteremic isolates carried qnr. These strains were multidrug-resistant, which was associated with inappropriate treatment and high fatality. Further dissemination of qnr and selection of fluoroquinolone/β-lactam-resistant strains should be closely monitored and controlled.