Contaminants in blood cultures: importance, implications, interpretation and prevention.

BACKGROUND: Despite the development of new microbiologic technologies, blood cultures (BCs) remain the first-line tool for the diagnosis of bloodstream infections. Their diagnostic value may be affected when a microorganism of questionable evidence is isolated-for example, coagulase-negative staphylococci, Bacillus spp., viridans group streptococci, Corynebacterium spp., Propionibacterium spp. and Micrococcus spp. Finally, making a correct diagnosis of pathogenicity (vs. contamination) is challenging. AIMS: To review the current ways of dealing with the problem of BC contaminants (BCCs) and to provide practical suggestions to decrease BCC rates. SOURCES: PubMed electronic databases and existing reviews were searched up to December 2017 to retrieve relevant publications related to the topic. CONTENTS: This review describes the burden of BCC and analyses the main current issues and controversies in interpreting the occurrence of potential BC contaminants. It focuses on the best-described approaches to decide whether BCC is present and discusses the different strategies of prevention in adults. IMPLICATIONS: Each institution should have an efficient policy to prevent BCC, emphasizing the importance of following guidelines for prescribing and collecting BCs. Training healthcare workers should focus on detrimental influence on patient care and highlight the work and costs due to contaminants. The accurate differentiation of a contaminant from a true pathogen relies on a multidisciplinary approach and the clinical judgement of experienced practitioners.

Severe cryptococcal-associated neurological immune reconstitution inflammatory syndrome in a renal transplant recipient treated with adalimumab.

Cryptococcosis is a major concern in organ transplant recipients. A decrease in immunosuppressants following the initiation of antifungal therapy is currently recommended, but can occasionally be complicated by the onset of immune reconstitution inflammatory syndrome (IRIS). We report on a case of cryptococcosis in a kidney transplant recipient, compounded by severe neurological IRIS, the outcome of which was unfavorable despite the use of anti-tumor necrosis factor-alpha monoclonal antibodies.

Non-carbapenem therapy of urinary tract infections caused by extended-spectrum ß-lactamase-producing Enterobacteriaceae.

PURPOSE: We determined the prevalence of ESBL Enterobacteriaceae in urinary tract infections among inpatients, identified risk factors of acquisition, and evaluated the effectiveness of alternatives to carbapenems. METHODS: The clinical, microbiological, and therapeutic data as well as the outcomes were recorded for all ESBL-E positive urine samples for three months. RESULTS: Thirty-one (4%) of the 762 Enterobacteriaceae positive cultures were ESBL producers. The predisposing conditions for being infected with those strains were: immunodepression (61%), recent hospitalization (52%), recent antibiotic therapy (52%), and urinary catheterization (61%). 19% of infections were community acquired. The seven cases of acute pyelonephritis and five of prostatitis were treated with piperacillin-tazobactam (5), fluoroquinolones (4), ceftazidime (2), or carbapenems (only 1) after specialized advice. Four (33%) patients relapsed at week 10: three were immunodepressed and three presented with bacteremia. CONCLUSIONS: Alternatives to carbapenems (especially piperacillin-tazobactam) seem to be a good option for non-bacteremic UTI in immunocompetent patients.

Unique blood culture for diagnosis of bloodstream infections in emergency departments: a prospective multicentre study.

Detection of microorganisms by blood cultures (BCs) is essential in managing patients with bacteraemia. Rather than the number of punctures, the volume of blood drawn is considered paramount in efficient and reliable detection of microorganisms. We performed a 1-year prospective multicentre study in adult emergency departments of three French university hospitals comparing two methods for BCs: a unique blood culture (UBC) collecting a large volume of blood (40 mL) and the standard method of multiple blood cultures (MBC). The performances of both methods for bacterial contamination and efficient microbial detection were compared, each patient serving as his own control. Amongst the 2314 patients included, three hundred were positive for pathogens (n=245) or contaminants (n=55). Out of the 245 patients, 11 were positive for pathogens by UBC but negative by MBC and seven negative by UBC but positive by MBC (p 0.480). In the subgroup of 137 patients with only two BCs, UBC was superior to MBC (p 0.044). Seven and 17 patients had contaminated BCs by UBC and MBC only, respectively (p 0.062). Considering the sums of pathogens missed and contaminants, UBC significantly outperformed MBC (p 0.045). Considering the complete picture of cost savings, efficient detection of microorganisms and decrease in contaminations, UBC offers an interesting alternative to MBC.

Fumagillin-induced aseptic meningoencephalitis in a kidney transplant recipient with microsporidiosis.

Microsporidiosis is an opportunistic infection in organ transplant recipients and patients with other cellular immunodeficiency. Fumagillin is an effective treatment against Enterocytozoon bieneusi, one of the two main species causing the microsporidiosis involved in human diseases. We report the first case, to our knowledge, of a probable drug-induced aseptic meningoencephalitis, after administration of fumagillin in a kidney transplant recipient with microsporidiosis.

[Epidemiology of candidemia: a one-year prospective observational study in the west of France]. / Epidémiologie des candidémies: étude observationnelle prospective d'un an dans l'Ouest de la France.

OBJECTIVE: A one-year prospective, observational study was conducted in the west of France, to evaluate the epidemiology of candidemia. METHOD: During the year 2004, each patient with at least one blood culture yielding Candida sp. was included. For each episode of candidemia, mycological, demographical, clinical, and therapeutic data, as well as outcome, were collected. RESULTS: One hundred and ninety-three strains of Candida sp. were isolated in 186 patients, Candida albicans accounting for 54.9%, Candida glabrata for 18.7%, Candida parapsilosis for 12.9%, Candida tropicalis for 4.7% and Candida krusei for 4.1% of these isolates. A percentage of 84% of the Candida isolates were fully susceptible to fluconazole in vitro. Dose-dependent susceptibility or resistance to fluconazole was detected in more than one third of the Candida glabrata strains, of which 36% were also resistant to voriconazole. Two-thirds of the patients were males, and the mean age was 61.5 years. A percentage of 37% of patients were hospitalized in intensive care units. The main predisposing factors for candidemia were broad-spectrum antibiotics (75.8%), central venous catheter (72.6%), cancer or hematologic malignancy (47.3%), recent surgery (42.5%), total parenteral nutrition (37.6%). One hundred and fifty-four patients were treated with antifungal therapy, two-thirds of whom received fluconazole as first-line agent. Mortality was 49% overall, and was significantly higher in case of septic shock, advanced age, and absence of catheter removal.

[Pyogenic-liver abscess: diagnosis and management]. / Abcès à pyogènes du foie. Diagnostic et prise en charge.

Pyogenic-liver abscesses are due to bacteria mostly from the portal and biliary tracts. There is usually only one located in the right liver, but they may be found in the left liver, be multiple or multilocular. Diagnosis, based on ultrasound and/or computed tomography scan, is confirmed by percutaneous-needle aspiration to identify the bacteria causing the disease. Global management includes the treatment of sepsis and the aetiology of the liver abscess: biliary lithiasis, diverticular disease, colon cancer, appendicitis or other intra-abdominal infections. However, no cause is found in 20% of cases. Treatment is based on antibiotics and, sometimes, percutaneous drainage while the cause may be treated immediately or later if the sepsis is controlled. Interventional radiology is often used. Surgery may be performed in case of failure of initial treatment and to cure the cause of the abscess. Prognosis may be poor, especially if there are associated-risk factors, such as diabetes and immunodepression, even though the outcome has improved with a multidisciplinary approach.

[Acute renal failure with acyclovir in a 42-year-old patient without previous renal dysfunction]. / Insuffisance rénale aiguë sous aciclovir chez un patient de 42 ans sans atteinte rénale préalable.

INTRODUCTION: Herpetic meningoencephalitis is treated with acyclovir (15 mg/kg/8 h). This higher dosage enhance the risk of acute renal failure. CASE REPORT: We report the case of a previously healthy 42 years old man treated by intravenous aciclovir 1g/8 h for a herpetic meningoencephalitis. He presented an acute renal failure and an acute confusional state at the end of the treatment. Renal function and neurologic status improved rapidly with increased hydration and stop of the antiviral therapy. CONCLUSION: If acyclovir is usually well tolerated, there is also a risk of acute nephropathy, especially dose-dependent. We point out the need to monitor renal function when high dosage of acyclovir is indicated.