P. aeruginosa bloodstream infections among hematological patients: an old or new question?

Prospective Evaluation of Infection Episodes in Cancer Patients in a Tertiary Care Academic Center: Microbiological Features and Risk Factors for Mortality

OBJECTIVE

We aimed to determine the frequency, type, and etiology of infections and the risk factors for infections and mortality in hospitalized cancer patients.

MATERIALS AND METHODS

We prospectively enrolled adult cancer patients hospitalized in the internal medicine wards of a tertiary care academic center between January and August 2004. Patients were followed during their hospitalization periods for neutropenia, infections, culture results, and mortality.

RESULTS

We followed 473 cancer patients with 818 hospitalization episodes and 384 infection episodes in total. Seventy-nine percent of the infections were nosocomial, and febrile neutropenia (FN) was observed in 196 (51%) of the infection episodes. Bacteremia was found in 29% of FN episodes and in 8% of nonneutropenic patients. Gram-positive bacteria were the leading cause of bacteremia in both neutropenic and nonneutropenic cases (70% and 58%, respectively). Presence of an indwelling central catheter increased bacteremia risk by 3-fold. The overall mortality rate was 17%, whereas 34% of the patients with bloodstream infections died. Presence of bacteremia and advanced disease stage increased overall mortality by 6.1-fold and 3.7-fold, respectively.

CONCLUSION

Nearly half of the cancer patients developed an infection during their hospital stays, with gram-positive bacteria being the predominant etiologic microorganisms. This demonstrates the changing trends in infections considering that, until 2004, gram-negative bacteria were the most predominant microorganisms among cancer patients in our institute.

Bloodstream infections in neutropenic cancer patients: A practical update

Bloodstream infections (BSI) are among the most frequent complications in neutropenic cancer patients and, if caused by Gram-negative rods, are associated with high mortality. Thus, fever during neutropenia warrants prompt empirical antibiotic therapy which should be active against the most frequent Gram-negatives. In the last decade, there has been a worldwide increase in multidrug resistant (MDR) strains. In these cases, the traditional choices such as oral therapy, ceftazidime, cefepime, piperacillin-tazobactam, or even carbapenems, might be ineffective. Therefore novel de-escalation approach has been proposed for patients who are at high risk for infections due to MDR bacteria. It consists of starting antibiotics which cover the most probable resistant strain but it is narrowed down after 72 hours if no MDR pathogen is isolated. With increasing bacterial resistance, the benefit of fluoroquinolone prophylaxis during prolonged neutropenia remains to be confirmed. Antibiotic stewardship and infection control programs are mandatory in every cancer center.

Bloodstream infections in patients with malignancies: implications for antibiotic treatment in a Ghanaian tertiary setting

Background

Bloodstream infections (BSI) remain a major cause of mortality in patients with malignancies. We present the first report on the microbiological profile of bacteraemia and fungaemia among cancer patients in Ghana.

Methods

From January 2010 through December 2013, we retrospectively analyzed the spectrum of bloodstream pathogens in cancer patients from Korle-Bu Teaching Hospital, Ghana—focusing on multidrug resistant isolates (MDRs).

Results

Overall BSI were confirmed in 22 % (n = 93/453) of total blood cultures. Our data highlights a co-dominance of Gram-negative (n = 49/93, 52.6 %) and Gram-positive (n = 40/93, 43.0 %) bacteria with the former less likely to infect children than adults [odds ratio (OR), 0.56; 95 % confidence interval (CI) 0.14–0.91; p value = 0.027]. Staphylococcus epidermidis was the most isolated bacteria (30.1 %; n = 28/93). About 61 % (n = 25/41) of Enterobacteriaceae isolates were resistant to cefotaxime; a majority (n = 24/25, 96 %) of which were MDRs and mostly susceptible to amikacin and levofloxacin. Four (80 %) penicillin resistant streptococci were found; 2 of which were MDRs and sensitive to erythromycin and cefuroxime. Methicillin resistant Staphylococcus aureus and vancomycin resistant enterococci were not identified. In multivariate analysis, the Enterobacteriaceae compared to other organisms were significantly associated with multidrug resistance (adjusted OR, 33.6; 95 % CI 6.41–88.73; p value 0.001).

Conclusion

MDRs, especially cefotaxime resistant Enterobacteriaceae, are common among patients with cancer in our institution but vary among different patient populations. The results show that empiric antibiotic treatment for cancer patients cannot be done effectively without regard for selective antimicrobial use based on local epidemiologic data.

The challenge of antibiotic resistance in haematology patients

Bacterial infections were once a major obstacle to the treatment of acute leukaemia. Improvement in management strategies, including the use of broad-spectrum antibacterial drugs targeting Gram-negative bacteria, has reduced the mortality in neutropenic patients developing blood stream infections and other severe infections. In many countries these achievements are threatened by development of multi-resistant bacteria, such as Klebsiella pneumoniae, Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus. This review addresses the epidemiology, clinical importance and possible management of these multi-resistant organisms.

The prevention and management of infections due to multidrug resistant organisms in haematology patients

Infections due to resistant and multidrug resistant (MDR) organisms in haematology patients and haematopoietic stem cell transplant recipients are an increasingly complex problem of global concern. We outline the burden of illness and epidemiology of resistant organisms such as gram-negative pathogens, vancomycin-resistant Enterococcus faecium (VRE), and Clostridium difficile in haematology cohorts. Intervention strategies aimed at reducing the impact of these organisms are reviewed: infection prevention programmes, screening and fluoroquinolone prophylaxis. The role of newer therapies (e.g. linezolid, daptomycin and tigecycline) for treatment of resistant and MDR organisms in haematology populations is evaluated, in addition to the mobilization of older agents (e.g. colistin, pristinamycin and fosfomycin) and the potential benefit of combination regimens.

Alarming and increasing prevalence of multidrug-resistant Pseudomonas aeruginosa among healthcare-associated infections in China: A meta-analysis of cross-sectional studies

A number of studies have reported on the prevalence of multidrug-resistant Pseudomonas aeruginosa (MDR-PA) among healthcare-associated infections (HAIs) in China; however, the exact rate of MDR-PA is unclear due to different definitions. Therefore, this meta-analysis was conducted to explore the prevalence of MDR-PA among HAIs in China based on an international recommended standard. Medline, Ovid, Cochrane Library, China National Knowledge Infrastructure (CNKI) and Wanfang databases were systematically searched and papers published before February 2014 providing exact data on MDR-PA in the Chinese population were identified. Overall effects, subgroup analysis and sensitivity analysis were performed using Stata v.13.0 software. Twenty-six studies were finally included. The overall prevalence of MDR-PA was 29.0% (95% confidence interval 24.6-33.4%). The rate of MDR-PA increased over time (P<0.001). The prevalence of MDR-PA was higher among patients in intensive care units (ICUs) (41.4%) than among non-ICU patients (24.1%) (P<0.001). In conclusion, the present meta-analysis comprehensively evaluated the prevalence of MDR PA in China and the findings suggest that MDR-PA should receive more attention.

Evaluation of antibacterial activity, phytochemical constituents, and cytotoxicity effects of Thai household ancient remedies

AIM

Household ancient remedies reported here are described in the National List of Essential Medicines and have traditionally been used in Thailand to treat infection-related ailments. However, the safety and effectiveness of these remedies have been poorly evaluated. The aim of this study was to evaluate the antibacterial properties of these remedies against seven gram-positive and gram-negative multidrug-resistant bacteria species. Phytochemical constituents and cytotoxicity of these remedies were also determined.

METHODS

Seven remedies, consisting of Um-Ma-Luk-Ka-Wa-Tee, Chan-Ta-Lee-La, Kheaw-Hom, Learng-Pid-Sa-Mud, Pra-Sa-Chan-Dang, Dhart-Ban-Chob, and Tree-Hom, were prepared by a licensed traditional medical doctor using a mixture of medicinal plants. Antibacterial activity of ethanol extracts of the remedies was determined by using a broth microdilution method. Qualitative phytochemical screening analysis was carried out to identify the presence of major components. Cytotoxicity activities of the extracts against Vero cells were assessed by green fluorescent protein-based assay.

RESULTS

With the exception of Dhart-Ban-Chob extract, significant minimum inhibitory concentrations (MICs) of <16 to 32 μg/mL were observed for the remedy extracts depending on the bacterial strains. The Um-Ma-Luk-Ka-Wa-Tee extract was noncytotoxic against Vero cells and possessed the highest activity, with MICs of <16 to 31 μg/mL against all methicillin-resistant Staphylococcus aureus isolates.

CONCLUSIONS

Remarkable antibacterial activities against multidrug-resistant pathogens, as well as low toxicity on Vero cells, of Um-Ma-Luk-Ka-Wa-Tee support the use of this remedy in traditional medicine. Further investigation on other biological activities related to traditional applications, appropriate biomarkers, and treatment mechanisms of the household remedy are required.

Antibiotic-resistant gram-negative bacterial infections in patients with cancer

Patients with cancer are at high risk for infections caused by antibiotic resistant gram-negative bacteria. In this review, we summarize trends among the major pathogens and clinical syndromes associated with antibiotic resistant gram-negative bacterial infection in patients with malignancy, with special attention to carbapenem and expanded-spectrum β-lactam resistance in Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia--all major threats to our cancer patients. Optimal therapy for these antibiotic-resistant pathogens still remains to be determined.

New Insight on Epidemiology and Management of Bacterial Bloodstream Infection in Patients with Hematological Malignancies

Bloodstream infections (BSI) are a significant cause of morbidity and mortality in onco-hematologic patients. The Gram-negative bacteria were the main responsible for the febrile neutropenia in the sixties; their impact declined due to the use of fluoroquinolone prophylaxis. This situation was followed by the gradual emergence of Gram-positive bacteria also following the increased use of intravascular devices and the introduction of new chemotherapeutic strategies. In the last decade, the Gram-negative etiology is raising again because of the emergence of resistant strains that make questionable the usefulness of current strategies for prophylaxis and empirical treatment. Gram-negative BSI attributable mortality is relevant, and the appropriate empirical treatment significantly improves the prognosis; on the other hand the adequate delayed treatment of Gram-positive BSI does not seem to have a high impact on survival. The clinician has to be aware of the epidemiology of his institution and colonizations of his patients to choose the most appropriate empiric therapy. In a setting of high endemicity of multidrug-resistant infections also the choice of targeted therapy can be a challenge, often requiring strategies based on off-label prescriptions and low grade evidence.

In this review, we summarize the current evidence for the best targeted therapies for difficult to treat bacteria BSIs and future perspectives in this topic. We also provide a flow chart for a rational approach to the empirical treatment of febrile neutropenia in a multidrug resistant, high prevalence setting.

Is admission screening for Pseudomonas aeruginosa useful in haematologic patients? A prospective study with 1310 patients

Screening for Pseudomonas aeruginosa is recommended to guide empirical antimicrobial therapy in patients on high-risk units. However, evidence for this approach is scarce. We therefore screened 1310 patients with severe haematologic diseases for P. aeruginosa colonization at admission: 108 (8.2%) were positive, but only nine (0.7%; six with the same clone as in the screening isolate) subsequently developed a P. aeruginosa bloodstream infection (positive predictive value of screening, 8.6%; negative predictive value of screening, 99.5%). Routine screening for P. aeruginosa at admission did not sufficiently predict subsequent bloodstream infections caused by P. aeruginosa.

Risk factors for multidrug-resistant bacteremia in hospitalized cancer patients with febrile neutropenia: a cohort study

We conducted a prospective cohort study in a single tertiary hospital with the aim of assessing predictors of multidrug-resistant bacteremia in 307 cases of febrile neutropenia in adult patients with cancer. On multivariate analysis using stepwise logistic regression, age (P = .009), duration of neutropenia (P = .022), and presence of an indwelling central venous catheter (P = .022) were associated with bloodstream infection by multidrug-resistant bacteria.

Relapsing bloodstream infections during treatment of acute leukemia

Acute leukemia (AL) patients may experience more than one episode of bloodstream infection (BSI) caused by the same pathogen during the entire chemotherapy program. In order to identify factors influencing BSI recurrence (R-BSI) during subsequent phases of treatment, we analyzed all BSIs occurring to consecutively treated AL patients during a period of active epidemiologic surveillance at our institution between 2004 and 2011. Two hundred and fifty BSIs were observed in 138 patients receiving more than 1 cycle of chemotherapy. BSI due to the same pathogen recurred in 39/138 (28.3 %) patients. Gram-negative rods (GNRs) accounted for 59.6 % and Gram-positive cocci (GPCs) for 34.4 % of BSI. Four pathogens were involved in R-BSI: Escherichia coli, Pseudomonas aeruginosa, coagulase-negative staphylococci, and Streptococcus viridans. GNRs were significantly more frequent among R-BSI compared to non-relapsing BSI (nR-BSI) [69/94 (73.4 %) vs 70/156 (50.6 %), p < 0.0001]; in particular, E. coli accounted for 67 % of R-BSI vs 32.1 % of nR-BSI (p < 0.0001). Receiving more than four chemotherapy courses and having an extended spectrum β-lactamase (ESBL)-producing E. coli BSI at any time of treatment were significantly associated to R-BSI. A trend toward a higher mortality among R-BSI patients in comparison with nR-BSI was observed (17.9 and 7.1 %, respectively, p = 0.12). Among AL patients, R-BSI is a frequent phenomenon, which may contribute to the shift of epidemiology toward GNR and to a higher mortality. This should significantly impact the strategies of antibiotic prophylaxis and treatment in patients with AL.

Surveillance and correlation of antimicrobial usage and resistance of Pseudomonas aeruginosa: a hospital population-based study

This retrospective study evaluated trends and association between resistance of Pseudomonas aeruginosa isolated from patients with hospital-acquired infections (HAIs) and hospital antimicrobial usage from 2003 through 2011 in a tertiary care hospital in northeast China. HAI was defined as occurrence of infection after hospital admission, without evidence that infection was present or incubating (≦48 h) on admission. In vitro susceptibilities were determined by disk diffusion test and susceptibility profiles were determined using zone diameter interpretive criteria, as recommended by Clinical and Laboratory Standards Institute (CLSI). Data on usage of various antimicrobial agents, expressed as defined daily dose (DDD) per 1,000 patients-days developed by WHO Anatomical Therapeutical Chemical (ATC)/DDD index 2011, were collected from hospital pharmacy computer database. Most of 747 strains of P. aeruginosa were collected from respiratory samples (201 isolates, 26.9%), blood (179, 24.0%), secretions and pus (145, 19.4%) over the years. Time series analysis demonstrated a significant increase in resistance rates of P. aeruginosa to ticarcillin/clavulanic acid, piperacillin/tazobactam, cefoperazone/sulbactam, piperacillin, imipenem, meropenem, ceftazidime, cefepime, ciprofloxacin, and levofloxacin except aminoglycosides over time in the hospital (P<0.001). The rates of carbapenem-resistant P. aeruginosa (CRPA) isolated from patients with HAIs were 14.3%, 17.1%, 21.1%, 24.6%, 37.0%, 48.8%, 56.4%, 51.2%, and 54.1% over time. A significant increase in usage of anti-pseudomonal carbapenems (P<0.001) was seen. ARIMA models demonstrated that anti-pseudomonal carbapenems usage was strongly correlated with the prevalence of imipenem and meropenem-resistant P. aeruginosa (P<0.001). Increasing of quarterly CRPA was strongly correlated at one time lag with quarterly use of anti-pseudomonal carbapenems (P<0.001). Our data demonstrated positive correlation between anti-pseudomonal antimicrobial usage and P. aeruginosa resistance to several classes of antibiotics, but not all antimicrobial agents in the hospital.

Recent changes in bacteremia in patients with cancer: a systematic review of epidemiology and antibiotic resistance

Bacteremia remains a major cause of life-threatening complication in patients with cancer. Significant changes in the spectrum of microorganisms isolated from blood culture have been reported in cancer patients over the past years. The aim of our systematic review was to inventory the recent trends in epidemiology and antibiotic resistance of microorganisms causing bacteremia in cancer patients. Data for this review was identified by searches of Medline, Scopus and Cochrane Library for indexed articles and abstracts published in English since 2008. The principal search terms were: "antimicrobial resistance", "bacteremia", "bacterial epidemiology", "bloodstream infection", "cancer patients", "carbapenem resistance", "Escherichia coli resistance", "extended-spectrum β-lactamase producing E. coli", "febrile neutropenia", "fluoroquinolone resistance", "neutropenic cancer patient", "vancomycin-resistant Enterococcus", and "multidrug resistance". Boolean operators (NOT, AND, OR) were also used in succession to narrow and widen the search. Altogether, 27 articles were selected to be analyzed in the review. We found that Gram-negative bacteria were the most frequent pathogen isolated, particularly in studies with minimal use of antibiotic prophylaxis. Another important trend is the extensive emergence of antimicrobial-resistant strains associated with increased risk of morbidity, mortality and cost. This increasing incidence of antibiotic resistance has been reported in Gram-negative bacteria as well as in Gram-positive bacteria. This exhaustive review, reporting the recent findings in epidemiology and antibiotic resistance of bacteremia in cancer patients, highlights the necessity of local continuous surveillance of bacteremia and stringent enforcement of antibiotic stewardship programs in cancer patients.