Yu Mi Wi

Clinical significance and predictors of community-onset Pseudomonas aeruginosa bacteremia.

BACKGROUND Pseudomonas aeruginosa bacteremia is a serious and possibly fatal condition. It is important to determine the likelihood of P. aeruginosa bacteremia when Gram-negative sepsis is suspected in community-onset infection. METHODS We performed a retrospective cohort study to identify the risk factors for P. aeruginosa infection in community-onset Gram-negative bacteremia. RESULTS A total of 106 patients with P. aeruginosa bacteremia and a total 508 patients with E. coli bacteremia were included in this study. Factors associated with P. aeruginosa bacteremia in the multivariate analysis included presentation with neutropenia, presentation with septic shock, indwelling central venous catheter, and health-care-associated infection (all P <.05). The 30-day mortality rate was 26.4% in patients with P. aeruginosa and 13.6% in those with E. coli bacteremia (P <.001). Multivariate analysis demonstrated that risk factors for mortality included a P. aeruginosa bacteremia, inappropriate initial antimicrobial therapy, a higher Charlsons weighted index of comorbidity, and a higher Pitt bacteremia score (all P <.05). In addition, urinary tract infection and benign pancreatobiliary disease were found to be protective factors for mortality based on multivariate analysis (all P <.05). CONCLUSIONS Our data suggest that initial empirical antimicrobial coverage of P. aeruginosa should be seriously considered in patients with neutropenia, presentation with septic shock, indwelling central venous catheter, or health-care-associated infection, when Gram-negative sepsis is suspected in community-onset infection.

Epidemiology and Risk Factors of Community Onset Infections Caused by Extended-Spectrum β-Lactamase-Producing Escherichia coli Strains

ABSTRACT Limited clinical information is available regarding community onset infections caused by extended-spectrum β-lactamase (ESBL)-producing Escherichia coli. A case-control study was performed to evaluate the epidemiology and risk factors of these types of infections. A case patient was defined as a person whose clinical sample yielded ESBL-producing E. coli. For each case patient, one control was randomly chosen from a group of outpatients from whom non-ESBL-producing E. coli had been isolated and for whom a clinical sample had been sent to the same laboratory for culturing during the following week. Of 108 cases of ESBL-producing E. coli, 56 (51.9%) were classified as health care associated (HCA). Univariate analysis showed male gender, HCA infection, severe underlying illness, and a prior receipt of antibiotics to be associated with ESBL-producing E. coli. In the multivariate analysis, HCA infection (odds ratio [OR], 3.18; 95% confidence interval [CI], 1.67 to 6.06; P < 0.001) and previous use of antibiotics (OR, 4.88; 95% CI, 2.08 to 11.48; P < 0.001) were found to be significantly associated with the ESBL group. In a multivariate analysis that included each antibiotic, previous use of fluoroquinolone (OR, 7.32; 95% CI, 1.58 to 34.01; P = 0.011) was significantly associated with ESBL-producing E. coli. Of 101 isolates in which ESBLs and their molecular relationships were studied, all isolates produced ESBLs from the CTX-M family (CTX-M-14, 40 isolates; CTX-M-15, 39 isolates; and other members of the CTX-M family, 22 isolates). In conclusion, this study confirms that ESBL-producing E. coli strains are a notable cause of community onset infections in predisposed patients. HCA infection and previous use of fluoroquinolone were significant factors associated with ESBL-producing E. coli in community onset infections.

Clinical and Molecular Epidemiology of Community-Onset Bacteremia Caused by Extended-Spectrum β-Lactamase-Producing Escherichia coli over a 6-Year Period

Although extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC) has emerged as a significant community-acquired pathogen, there is little epidemiological information regarding community-onset bacteremia due to ESBL-EC. A retrospective observational study from 2006 through 2011 was performed to evaluate the epidemiology of community-onset bacteremia caused by ESBL-EC. In a six-year period, the proportion of ESBL-EC responsible for causing community-onset bacteremia had increased significantly, from 3.6% in 2006 to 14.3%, in 2011. Of the 97 clinically evaluable cases with ESBL-EC bacteremia, 32 (33.0%) were further classified as healthcare-associated infections. The most common site of infection was urinary tract infection (n=35, 36.1%), followed by biliary tract infections (n=29, 29.9%). Of the 103 ESBL-EC isolates, 43 (41.7%) produced CTX-M-14 and 36 (35.0%) produced CTX-M-15. In the multilocus sequence typing (MLST) analysis of 76 isolates with CTX-M-14 or -15 type ESBLs, the most prevalent sequence type (ST) was ST131 (n=15, 19.7%), followed by ST405 (n=12, 15.8%) and ST648 (n=8, 10.5%). No significant differences in clinical features were found in the ST131 group versus the other group. These findings suggest that epidemic ESBL-EC clones such as CTX-M-14 or -15 type ESBLs and ST131 have disseminated in community-onset infections, even in bloodstream infections, which are the most serious type of infection.

Epidemiology and clinical outcomes of bloodstream infections caused by extended-spectrum β-lactamase-producing Escherichia coli in patients with cancer.

Patients with cancer can be vulnerable to infection with antimicrobial-resistant pathogens such as extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae. A cohort study was performed to evaluate the epidemiology and impact of ESBL-producing Escherichia coli (ESBL-EC) bacteraemia on the outcomes of adult patients with cancer. During the 2.5-year study period, a total of 350 cases of E. coli bacteraemia were documented in cancer patients, of which 95 (27.1%) were due to ESBL-EC. Significant factors associated with ESBL-EC bacteraemia were liver disease, immunosuppressant use, recent surgery, and prior use of cephalosporins or fluoroquinolones. The overall 30-day mortality rate was 14.9% (52/350), and the mortality rate was higher in patients with ESBL-EC than in those without ESBL-EC (22.1% vs.12.2%; P=0.02). Multivariate analysis showed that ESBL-EC was an independent risk factor for mortality (odds ratio=3.01, 95% confidence interval 1.45-6.28; P=0.003), along with the presence of septic shock, mechanical ventilation, the severity of underlying diseases, and pneumonia as a source of bacteraemia. Of the 69 isolates in which ESBLs and their molecular relationships were studied, 68 (98.6%) produced CTX-M-type and 51 (73.9%) produced CTX-M-14 and/or CTX-M-15. Twenty-four sequence types (STs) were identified among CTX-M-14- and CTX-M-15-producing E. coli isolates, with ST131 being the most prevalent (12/51; 23.5%). In conclusion, this study confirms that CTX-M-producing E. coli and ST131, which have been shown to be an emerging public health threat, are widely prevalent in cancer patients and can adversely affect the outcome of E. coli bacteraemia in these patients.

Clinical implications of healthcare-associated infection in patients with community-onset acute pyelonephritis

Abstract Background: Clinical and microbiological characteristics of healthcare-associated acute pyelonephritis (HCA-APN) have not been described in detail yet. We sought to delineate the differences between community-associated (CA)- and HCA-APN with specific interest in antibiotic resistance of causative microorganisms. Methods: We conducted a retrospective cohort study during a 1-y period at a large referral center. Patients who visited the emergency department with symptoms and signs of APN were included in the study population. Results: Among 319 cases with community-onset APN, 201 cases (63%) were classified as HCA-APN. Patients with HCA-APN had higher SOFA (sequential organ failure assessment) scores, longer length of hospital stay and a lower rate of complete response to antimicrobial therapy. Patients with complicated APN also had characteristics similar to those seen in HCA-APN. However, 14-day mortality rates were not different between CA-APN vs HCA-APN and between uncomplicated APN vs complicated APN. With regard to microbiological characteristics, Escherichia coli were less common in HCA-APN than in CA-APN (62.7% vs 93.2%, p < 0.001). Among E. coli isolates, quinolone resistance and extended-spectrum beta-lactamase (ESBL) production were more common in HCA-APN than in CA-APN (38.9% vs 12.7%, p < 0.001; 15.9% vs 0.8%, p < 0.001, respectively). Conclusions: HCA-APN, and complicated APN, represents a distinct subset of urinary tract infections with more antibiotic-resistant pathogens and worse outcomes, which physicians should consider to provide optimal treatment.

Tacrolimus as a risk factor for tuberculosis and outcome of treatment with rifampicin in solid organ transplant recipients.

The purpose of this study was to investigate the incidence, risk factors, and treatment outcome of tuberculosis (TB) in solid organ transplant (SOT) recipients treated with rifampicin.

High vancomycin minimum inhibitory concentration is a predictor of mortality in meticillin-resistant Staphylococcus aureus bacteraemia.

Failure of vancomycin in the treatment of meticillin-resistant Staphylococcus aureus (MRSA) bacteraemia has been reported despite full susceptibility of the organism to vancomycin. A retrospective observational cohort study including 137 patients with MRSA bacteraemia was performed at two centres in South Korea during 2009-2010. A total of 137 patients with MRSA bacteraemia receiving vancomycin therapy were enrolled during the study period. Isolates from 13 (9.5%) of the 137 patients had minimum inhibitory concentrations (MICs) ≥1 μg/mL. The 30-day cumulative survival was 53.8% for patients infected with isolates having a MIC≥1 μg/mL and 79.8% for patients infected with isolates having a MIC<1 μg/mL (log-rank test, P=0.026). Vancomycin MIC≥1 μg/mL [hazard ratio (HR)=7.0, 95% confidence interval (CI) 2.2-22.1; P=0.001], nosocomial acquisition of bacteraemia (HR=5.4, 95% CI 1.4-20.1; P=0.013), rapidly fatal underlying diseases (HR=20.5, 95% CI 3.9-106.4; P<0.001), presentation with septic shock (HR=8.4, 95% CI 3.0-23.3; P<0.001), presence of complicated infections (HR=5.6, 95% CI 2.0-15.8; P=0.001) and persistent MRSA bacteraemia for ≥3 days (HR=4.2, 95% CI 1.4-12.7; P=0.012) were independent predictors of 30-day mortality in patients with MRSA bacteraemia. In patients with high Pitt bacteraemia scores (Pitt score ≥2), the delay in initiation of vancomycin therapy was significantly different between non-survivors and survivors (2.4 days vs. 1.1 days; P=0.012). Vancomycin MIC≥1 μg/mL had a significant impact on mortality of patients with MRSA bacteraemia. These findings support early consideration of alternative anti-MRSA agents in patients with MRSA bacteraemia who have high vancomycin MICs as well as prompt initiation of anti-MRSA treatment in patients with MRSA bacteraemia, especially those with high Pitt scores.

Spontaneous Bacterial Peritonitis due to Ochrobactrum anthropi : A Case Report

We report a case of spontaneous bacterial peritonitis from Ochrobactrum anthropi. O. anthropi is recognized as an emerging pathogen in immunocompromised patients. In contrast to most previously described cases, the patient reported here had no indwelling catheter. To our knowledge, no case of O. anthropi spontaneous bacterial peritonitis has been reported in the medical literature until now.

Bloodstream infections in adult patients with cancer: clinical features and pathogenic significance of Staphylococcus aureus bacteremia

ObjectivesThe aim of this study was to more precisely delineate the characteristics and outcomes of bloodstream infections in adult cancer patients.MethodsUsing a database for nationwide surveillance of bacteremia, we analyzed data related to bacteremia in adult patients with cancer in order to evaluate clinical features and outcomes and to define predictive factors for mortality.ResultsOf 1,246 patients, 896 (71.9%) had solid tumors, 328 (26.3%) had hematologic malignancies, and 22 (1.8%) had both. The following conditions were more common in the neutropenic group than in the non-neutropenic group: nosocomial acquisition, hematologic malignancy, corticosteroid use, immunosuppressant use, primary bacteremia, and pneumonia (all P < 0.05). The infections were caused by Gram-negative bacilli in 55.6% and by Gram-positive cocci in 32.7%. Gram-negative pathogens were more frequently isolated from neutropenic patients than from non-neutropenic patients (61.9% vs. 53.5%, P = 0.010), with a significant predominance of Escherichia coli and Klebsiella pneumoniae. Among 1,001 patients whose outcomes could be evaluated, the overall 30-day mortality rate was 24.1%, and multivariate analysis showed that Staphylococcus aureus bacteremia was a significant factor associated with mortality (odds ratio (OR), 1.80; 95% confidence interval (CI), 1.03–3.15), along with nosocomial acquisition, pneumonia, severe sepsis or septic shock, and higher Pitt bacteremia score (all P values <0.05).ConclusionThis study represents the comprehensive assessment of bloodstream infections in neutropenic versus non-neutropenic cancer patients. Given the pathogenic significance of S. aureus bacteremia in adult patients with cancer, additional strategies for the management of S. aureus bacteremia in cancer patients are needed to improve outcomes.

Risk Factors for Multidrug Resistance in Nosocomial Bacteremia Caused by Extended-Spectrum β-Lactamase-Producing Escherichia coli and Klebsiella pneumoniae

Increasing multidrug resistance (MDR) among extended-spectrum β-lactamase-producing Escherichia coli and Klebsiella pneumoniae (ESBL-EK) is of a great concern, because the therapeutic options are severely limited. Thus, we performed a case-control study to evaluate risk factors for MDR among nosocomial bacteremia caused by ESBL-EK. All adult patients with ESBL-EK bacteremia from January 2009 through December 2010 were identified at our institution. MDR was defined as ESBL-EK that demonstrated in vitro resistance to trimethoprim-sulfamethoxazole (TMP-SMX), fluoroquinolone (FQ), and gentamicin. Case patients were those with an MDR ESBL-EK isolate, and control patients were those with a non-MDR ESBL-EK isolate. Among a total of 123 ESBL-EK isolates (74 [60.2%] E. coli and 49 [39.8%] K. pneumoniae) causing nosocomial bacteremia, 33 (26.8%) cases were due to MDR ESBL-EK. In a univariate analysis, the factors significantly associated with acquisition of MDR ESBL-EK were neutropenia, immunosuppressant use, urinary tract infection, and prior use of antibiotics, especially FQ (all p<0.05). A multivariable analysis showed that a prior receipt of FQ (odds ratio [OR]=2.93; 95% confidence interval [CI]=1.07-8.01; p=0.036), percutaneous tube insertion (OR=4.04; 95% CI=1.56-10.75; p=0.005), and neutropenia (OR=4.22; 95% CI=1.56-11.45; p=0.005) were independent risk factors for MDR among ESBL-EK bacteremia in hospitalized patients. The CTX-M-15 enzyme was predominant in both the MDR ESBL-EK and non-MDR ESBL-EK groups (55% [11/20] vs. 55.6% [15/27]). Our data suggest that strategies designed to reduce MDR in ESBL-EK bacteremia should focus on limiting the use of FQ and minimizing invasive procedures such as tube insertion.