Clinical and prognostic features of prosthetic joint infections caused by Enterococcus spp

OBJECTIVE

Pathogens colonizing the intestinal or urinary tract such as enterococci or Gram-negative bacilli can cause prosthetic joint infection (PJI).

PATIENTS AND METHODS

PJI undergoing 2-stage exchange, referred to the Department of Infectious Diseases of the Cotugno Hospital of Naples and the Fondazione Policlinico Gemelli of Rome over a 7-year period (2009-2015) for Infectious Diseases (ID) consultation were included. Demographic data, detailed information about previous or underlying diseases, findings of the clinical examination, and results of laboratory investigations were analyzed. The cure was defined by the disappearance of clinical, laboratory, and radiological evidence of PJI 96 week after the discontinuation of antibiotic treatment.

RESULTS

Thirty-one cases of PJI sustained by Enterococci were included (16 early infections, 13 delayed infections, and 2 late infections). Median age was 73 years (range 39-83), 39% were males. Comorbidities related to an increased risk of infection were reported in 17 (55%) cases. Joint pain interfering with daily living was reported in 27 (87%) cases, fever in 7 with early infection and in no case with delayed or late infection (7/17 vs. 0/14, Odds ratio undefined, p=0.01). Local inflammation and joint effusion were reported in 29 (93%) cases, sinus tract in 25 (81%). Enterococcus faecalis was the etiologic agent in 28 (90%) cases, E. faecium in 2 (6%), E. casseliflavus in 1 (3%). Eleven cases were polymicrobial. Favourable outcome was reported in 20 (65%) cases. Patients with comorbidities reported more frequently an unfavourable outcome (9/17 vs. 2/14, Odds ratio 6.7, 95% CI 1.1-39.8; p=0.06).

CONCLUSIONS

Comorbidities should arise the suspect of infection by enterococci. Associative protocols, considering drugs active against biofilm should be considered in the cases with enterococcal infection.

Systemic antibiotic treatment of chronic osteomyelitis in adults

Chronic osteomyelitis is a difficult to treat infection of the bone, which requires a combined medical and surgical approach and often persists intermittently for years, with relapses and failures. The optimal type, route of administration, and duration of antibiotic treatment remain controversial, and the emergence of multi-drug resistant organisms poses major therapeutic challenges. Identification of the causative agent and subsequent targeted antibiotic treatment has a major impact on patients' outcome. In this review, we summarize which intravenous and oral antibiotics are the best options available for the treatment of chronic osteomyelitis, according to specific aetiologies.

Epidemiological and clinical features of prosthetic joint infections caused by gram-negative bacteria

OBJECTIVE

To review the clinical literature focusing on epidemiology, clinical presentation and outcomes of prosthetic joint infections (PJIs) due to gram-negative bacteria (GNB) and to report the experience of a multicentric cohort.

PATIENTS AND METHODS

A retrospective, observational, cohort study was performed in three Italian hospitals. All consecutive PJIs caused by GNB over a 12-year period (from May 2007 to March 2018) were enrolled. Epidemiological, clinical, microbiological and therapeutic features were described. Factors related to treatment failure (defined as the occurrence of death, amputation or starting long-term antimicrobial suppression therapy) were analysed with a Cox regression model.

RESULTS

A total of 82 PJIs due to GNB (42.7% men; median age 73 years) were studied. The implants included 65 (79.3%) hip, 16 (19.5%) knee and one (1.2%) shoulder. An early PJI was diagnosed in 16.2% of patients, a delayed PJI in 29.4% and a late PJI in 54.4%. The most common isolated organisms were Escherichia coli (21.7%) and Pseudomonas spp. (20.9%). 13.4% of the isolates were carbapenem-resistant bacteria (CRB). In 53.8% of cases a two-stage exchange arthroplasty was performed and in 32.5% a Girdlestone excision arthroplasty. The average therapeutic failure occurred in 17.7% of cases. The therapeutic failure rate of the two-stage was 10%. PJI due to CRB was identified as a potential risk factor for failure (aHR 4.90; IC 95%, 0.96-25.08; p=0.05). The therapeutic failure rate in the CRB group was 50%.

CONCLUSIONS

The treatment with the two-stage procedure for PJIs caused by GNB seems to be associated with a low rate of failure, while PJI due to CRB seems to be related to the worst outcome.

Procalcitonin is useful in driving the choice of early antibiotic treatment in patients with bloodstream infections

OBJECTIVE

To evaluate whether PCT levels could be used to distinguish among different bacterial and fungal etiologies in patients with documented bloodstream infection (BSI).

PATIENTS AND METHODS

Monocentric retrospective cohort study on patients admitted to the Fondazione Policlinico Gemelli Hospital between December 2012 and November 2015 with BSI. Those who had undergone PCT determination within 48 hours of when the first positive blood culture was sampled were included in the study.

RESULTS

Four hundred and one patients were included in the study. Both the 24h and 48h PCT values were significantly higher in patients with Gram-negative (GN) BSI than in those with Gram-positive (GP) or candida BSI (p at ANOVA = 0.003). A PCT value of > 1 ng/ml was found in 31.5% of patients with GN BSI. Less than 7% of people with candida BSI had PCT level of > 1 ng/ml. At multivariable regression analysis, GN BSI, septic shock, and plasma creatinine were significantly correlated with PCT values.

CONCLUSIONS

PCT may be of value in distinguishing GN BSI from GP, and fungal BSI and PCT values of > 1 ng/ml could be used to prevent unnecessary antifungal treatment.

A 72-h intervention for improvement of the rate of optimal antibiotic therapy in patients with bloodstream infections

Antimicrobial stewardship programs are implemented to optimize the use of antibiotics and control the spread of antibiotic resistance. Many antimicrobial stewardship interventions have demonstrated significant efficacy in reducing unnecessary prescriptions of antibiotics, the duration of antimicrobial therapy, and mortality. We evaluated the benefits of a combination of rapid diagnostic tests and an active re-evaluation of antibiotic therapy 72 h after the onset of bloodstream infection (BSI). All patients with BSI from November 2015 to November 2016 in a 1100-bed university hospital in Rome, where an Infectious Disease Consultancy Unit (Unità di Consulenza Infettivologica, UDCI) is available, were re-evaluated at the bedside 72 h after starting antimicrobial therapy and compared to two pre-intervention periods: the UDCI was called by the ward physician for patients with BSI and the UDCI was called directly by the microbiologist immediately after a pathogen was isolated from blood cultures. Recommendations for antibiotic de-escalation or discontinuation significantly increased (54%) from the two pre-intervention periods (32% and 27.2%, p < 0.0001). Appropriate escalation also significantly increased (22.5%) from the pre-intervention periods (8.1% and 8.2%, p < 0.0001). The total duration of antibiotic therapy decreased with intervention (from 21.9 days [standard deviation, SD 15.4] in period 1 to 19.3 days [SD 13.3] in period 2 to 17.7 days in period 3 [SD 11.5]; p = 0.002) and the length of stay was significantly shorter (from 29.7 days [SD 29.3] in period 1 to 26.8 days [SD 24.7] in period 2 to 24.2 days in period 3 [SD 20.7]; p = 0.04) than in the two pre-intervention periods. Mortality was similar among the study periods (31 patients died in period 1 (15.7%), 39 (16.7%) in period 2, and 48 (15.3%) in period 3; p = 0.90). Rapid diagnostic tests and 72 h re-evaluation of empirical therapy for BSI significantly correlated with an improved rate of optimal antibiotic therapy and decreased duration of antibiotic therapy and length of stay.