High Rate of Inappropriate Antibiotics in Patients with Hematologic Malignancies and Pseudomonas aeruginosa Bacteremia following International Guideline Recommendations

Optimal coverage of Pseudomonas aeruginosa is challenging in febrile neutropenic patients due to a progressive increase in antibiotic resistance worldwide. We aimed to detail current rates of resistance to antibiotics recommended by international guidelines for P. aeruginosa isolated from bloodstream infections (BSI) in patients with hematologic malignancies. Secondarily, we aimed to describe how many patients received inappropriate empirical antibiotic treatment (IEAT) and its impact on mortality. We conducted a retrospective, multicenter cohort study of the last 20 BSI episodes caused by P. aeruginosa in patients with hematologic malignancies from across 14 university hospitals in Spain. Of the 280 patients with hematologic malignancies and BSI caused by P. aeruginosa, 101 (36%) had strains resistant to at least one of the β-lactam antibiotics recommended in international guidelines, namely, cefepime, piperacillin-tazobactam, and meropenem. Additionally, 21.1% and 11.4% of the strains met criteria for MDR and XDR P. aeruginosa, respectively. Even if international guidelines were followed in most cases, 47 (16.8%) patients received IEAT and 66 (23.6%) received inappropriate β-lactam empirical antibiotic treatment. Thirty-day mortality was 27.1%. In the multivariate analysis, pulmonary source (OR 2.22, 95% CI 1.14 to 4.34) and IEAT (OR 2.67, 95% CI 1.37 to 5.23) were factors independently associated with increased mortality. We concluded that P. aeruginosa-causing BSI in patients with hematologic malignancies is commonly resistant to antibiotics recommended in international guidelines, which is associated with frequent IEAT and higher mortality. New therapeutic strategies are needed. IMPORTANCE Bloodstream infection (BSI) caused by P. aeruginosa is related with an elevated morbidity and mortality in neutropenic patients. For this reason, optimal antipseudomonal coverage has been the basis of all historical recommendations in the empirical treatment of febrile neutropenia. However, in recent years the emergence of multiple types of antibiotic resistances has posed a challenge in treating infections caused by this microorganism. In our study we postulated that P. aeruginosa-causing BSI in patients with hematologic malignancies is commonly resistant to antibiotics recommended in international guidelines. This observation is associated with frequent IEAT and increased mortality. Consequently, there is a need for a new therapeutic strategy.

mNGS facilitates the accurate diagnosis and antibiotic treatment of suspicious critical CNS infection in real practice: A retrospective study

Whether metagenomic next-generation sequencing (mNGS) could benefit patients with suspected severe central nervous system (CNS) infection in terms of diagnosis and antibiotic treatment remains unknown. We retrospectively analyzed 79 patients with suspected CNS infection and undertook mNGS. The value of mNGS was investigated in terms of identification of pathogen and guidance for the adjustment of antibiotic treatment. The relationship between the time of initiating mNGS since onset and the Glasgow Outcome Scale (GOS) score after 90-day follow-up were analyzed. Fifty out of 79 cases with suspicious severe CNS infection were finally diagnosed. Despite previous routine laboratory tests, mNGS further promoted the accurate identification of pathogens in 23 cases (47.9%). The sensitivity, specificity, and accuracy of mNGS test in this study were 84.0, 79.3, and 82.3%, respectively. Furthermore, mNGS facilitated the adjustment of empirical antibiotic treatments in 38 cases (48.1%). The time of taking mNGS since onset had an insignificant weak positive correlation with GOS after 90-day follow-up (r = -0.73, P = 0.08). mNGS facilitated the accurate identification of pathogens in suspicious severe CNS infections and promoted the accurate antibiotic therapy even empirical antibiotics were administrated. It should be taken as early as possible to improve the clinical outcome of patients with suspicious severe CNS infection.

Differing Microorganism Profile in Early and Late Prosthetic Joint Infections Following Primary Total Knee Arthroplasty - Implications for Empiric Antibiotic Treatment

BACKGROUND

Prosthetic joint infection (PJI) is the leading cause of revision following total knee arthroplasty (TKA). Prior to microorganism identification, the choice of the correct empiric antibiotics is critical to treatment success. This study aims to 1) compare the microorganism and resistance profile in early and late PJIs; 2) recommend appropriate empiric antibiotics.

METHODS

A multicentre retrospective review was performed over a 15-year period. First episode PJIs were classified by both the Tsukayama Classification and Auckland Classification. For each PJI case, the causative organism and antibiotic sensitivity were recorded.

RESULTS

Of eligible patients, 232 culture-positive PJI cases were included. Using either classification system, early PJIs (<4 weeks or <1 year since primary) were significantly more likely to be resistant and polymicrobial. The predominant organisms were coagulase-negative Staphylococci in early PJIs while Staphylococcus aureus was the most common in late PJIs. The distribution of gram-negative cases was higher in early Class-A than late Class-C PJIs (25% versus 6%, P = .004). Vancomycin provided significantly superior coverage when compared to Flucloxacillin for early infections, and addition of a gram-negative agent achieved coverage over 90% using both classification systems.

CONCLUSION

Based on the microbiological pattern in Tsukayama criteria, Vancomycin with the consideration of Gram-negative agent should be considered for Class-A infections given the high proportion of resistant and polymicrobial cases. For Class-C infections, Cephazolin or Flucloxacillin is likely sufficient. We recommend antibiotics to be withheld in Class-B infections until cultures and sensitivities are known.

Effect of Delays in Concordant Antibiotic Treatment on Mortality in Patients With Hospital-Acquired Acinetobacter Species Bacteremia: Emulating a Target Randomized Trial With a 13-Year Retrospective Cohort

Delays in treating bacteremias with antibiotics to which the causative organism is susceptible are expected to adversely affect patient outcomes. Quantifying the impact of such delays to concordant treatment is important for decision-making about interventions to reduce the delays and for quantifying the burden of disease due to antimicrobial resistance. There are, however, potentially important biases to be addressed, including immortal time bias. We aimed to estimate the impact of delays in appropriate antibiotic treatment of patients with Acinetobacter species hospital-acquired bacteremia in Thailand on 30-day mortality by emulating a target trial using retrospective cohort data from Sunpasitthiprasong Hospital in 2003–2015. For each day, we defined treatment as concordant if the isolated organism was susceptible to at least 1 antibiotic given. Among 1,203 patients with Acinetobacter species hospital-acquired bacteremia, 682 had 1 or more days of delays to concordant treatment. Surprisingly, crude 30-day mortality was lower in patients with delays of ≥3 days compared with those who had 1–2 days of delays. Accounting for confounders and immortal time bias resolved this paradox. Emulating a target trial, we found that these delays were associated with an absolute increase in expected 30-day mortality of 6.6% (95% confidence interval: 0.2, 13.0), from 33.8% to 40.4%.

Appropriateness of diagnosis and antibiotic use in sepsis patients admitted to a tertiary hospital in Indonesia

OBJECTIVE

To evaluate the diagnostic and antibiotic treatment strategies for patients suspected of sepsis, in a tertiary hospital in Indonesia. This can identify areas for improvement in care provided, and inform diagnostic and antimicrobial stewardship activities within the hospital.

METHODS

Retrospective review of medical records with regards to the diagnosis and management of adult patients with sepsis admitted to a tertiary hospital in Indonesia. We assessed the diagnostic process, and whether or not the antibiotic treatment provided was appropriate for the diagnosis. Appropriateness of antibiotic treatment was classified as being definite appropriate, probable appropriate, inappropriate, or unknown.

RESULTS

The study included 535 adult patients, of whom 295 (55%) were diagnosed with a community-acquired sepsis, and 240 (45%) with a hospital-acquired sepsis. A specimen for culture and antimicrobial susceptibility testing was collected from three out of four patients (392/535). All but 10 patients had information on antibiotic treatment at the time of sepsis diagnosis. Of those, nearly 50% (257/525) of the patients received antibiotic treatment with unknown appropriateness because no cultures were taken (n = 141) or all cultures were negative (n = 116). Just 3.4% and 9.1% of the patients received definite or probable appropriate antibiotic treatment, respectively.

CONCLUSIONS

There is a clear need in encouraging attending physicians to obtain the much-required blood cultures, or cultures from the suspected source of infection before empirical antibiotic treatment is started. This will improve the use of appropriate antibiotic treatment strategies, and contribute to antimicrobial stewardship.

Daptomycin versus Vancomycin as Post-Operative Empirical Antibiotic Treatment for Prosthetic Joint Infections: A Case-Control Study

Purpose: To compare safety and efficacy of Vancomycin (Van) versus Daptomycin (Dap) as post-operative empirical antibiotic treatment (PEAT) in patients with periprosthetic joint infections (PJIs).

Methods: Medical charts of patients treated empirically with Van or Dap in the post-operative period of total hip/knee prosthesis septic revision until the results of intra-operative culture were reviewed. Cefotaxime, cefepime or aztreonam were used in combination with Dap or Van.

Results: Twenty Dap patients were matched with 20 other Van patients according to the age and type of prosthesis. The ASA score and the distribution of the pathogens was similar in the two groups especially regarding the number of methicillin-resistant staphylococci. The mean duration of the PEAT was 6.07 ± 0.85 days. A total of 17 episodes of adverse events (AE) in 10 patients (25%) were recorded during the PEAT which led to discontinue the treatment in 5 patients, all of them treated with Van (P=0.02). At the end of a mean post-treatment follow-up of 618 +/- 219 days, 36 patients remained in remission of infection; 2 patients failed in each group.

Conclusions: Our observations suggest that PEAT with Van for septic revision of PJIs is associated with a higher discontinuation rate due to AE but with a similar outcome than it is with Dap.

Risk factors, outcome and impact of empirical antimicrobial treatment in extended-spectrum β-lactamase-producing Escherichia coli bacteraemia

BACKGROUND

To investigate patient characteristics and empirical antimicrobial treatment of extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC) bacteraemia, to determine risk factors, outcome and impact of empirical antimicrobial treatment.

METHODS

We performed a retrospective case-control study of all patients diagnosed with ESBL-EC from January 2011 to September 2012. The control group consisted of patients with non-ESBL E. coli bacteraemia. The groups were compared with respect to empirical treatment, risk factors and outcome, using univariate and multivariate analysis.

RESULTS

The study consisted of 70 consecutive cases of ESBL-producing and 140 controls of non-ESBL-producing E. coli bacteraemia. ESBL-EC prevalence of bloodstream invasive E. coli isolates was 6.1%. The independent risk factor found for ESBL-EC bacteraemia was a prior culture with ESBL production (p < 0.001). A higher frequency of inappropriate empirical antibiotic treatment (p < 0.001) and a trend towards worse outcome was observed in patients infected with ESBL-EC and empirical guidelines were more often not followed (p = 0.013). If the guidelines were followed this was associated with adequate initial antibiotic treatment (p < 0.001).

CONCLUSIONS

Patients with ESBL-EC frequently received inappropriate empirical treatment and guidelines were more often not followed. A prior culture of ESBL-producing bacteria was an independent predictor and risk factor for ESBL-EC bacteraemia. Since the prevalence of ESBL-producing E. coli is increasing the importance of adequate guidelines must be emphasized.