Predictors of outcome in patients with severe sepsis or septic shock due to extended-spectrum β-lactamase-producing Enterobacteriaceae

PURPOSE

There are few data in the literature regarding sepsis or septic shock due to extended-spectrum β-lactamases (ESBL)-producing Enterobacteriaceae (E). The aim of this study was to assess predictors of outcome in septic patients with bloodstream infection (BSI) caused by ESBL-E.

METHODS

Patients with severe sepsis or septic shock and BSI due to ESBL-E were selected from the INCREMENT database. The primary endpoint of the study was the evaluation of predictors of outcome after 30 days from development of severe sepsis or septic shock due to ESBL-E infection. Three cohorts were created for analysis: global, empirical-therapy and targeted-therapy cohorts.

RESULTS

367 septic patients were analysed. Overall mortality was 43.9% at 30 days. Escherichia coli (62.4%) and Klebsiella pneumoniae (27.2%) were the most frequent isolates. β-lactam/β-lactamase inhibitor (BLBLI) combinations were the most empirically used drug (43.6%), followed by carbapenems (29.4%). Empirical therapy was active in vitro in 249 (67.8%) patients, and escalation of antibiotic therapy was reported in 287 (78.2%) patients. Cox regression analysis showed that age, Charlson Comorbidity Index, McCabe classification, Pitt bacteremia score, abdominal source of infection and escalation of antibiotic therapy were independently associated with 30-day mortality. No differences in survival were reported in patients treated with BLBLI combinations or carbapenems in empirical or definitive therapy.

CONCLUSIONS

BSI due to ESBL-E in patients who developed severe sepsis or septic shock was associated with high 30-day mortality. Comorbidities, severity scores, source of infection and antibiotic therapy escalation were important determinants of unfavorable outcome.

Impact of Staphylococcus aureus phenotype and genotype on the clinical characteristics and outcome of infective endocarditis. A multicentre, longitudinal, prospective, observational study

OBJECTIVE

We aimed to evaluate the impact of Staphylococcus aureus phenotype (vancomycin MIC) and genotype (agr group, clonal complex CC) on the prognosis and clinical characteristics of infective endocarditis (IE).

METHODS

We performed a multicentre, longitudinal, prospective, observational study (June 2013 to March 2016) in 15 Spanish hospitals. Two hundred and thirteen consecutive adults (≥18 years) with a definite diagnosis of S. aureus IE were included. Primary outcome was death during hospital stay. Main secondary end points were persistent bacteraemia, sepsis/septic shock, peripheral embolism and osteoarticular involvement.

RESULTS

Overall in-hospital mortality was 37% (n = 72). Independent risk factors for death were age-adjusted Charlson co-morbidity index (OR 1.20; 95% CI 1.08-1.34), congestive heart failure (OR 3.60; 95% CI 1.72-7.50), symptomatic central nervous system complication (OR 3.17; 95% CI 1.41-7.11) and severe sepsis/septic shock (OR 4.41; 95% CI 2.18-8.96). In the subgroup of methicillin-susceptible S. aureus IE (n = 173), independent risk factors for death were the age-adjusted Charlson co-morbidity index (OR 1.17; 95% CI 1.03-1.31), congestive heart failure (OR 3.39; 95% CI 1.51-7.64), new conduction abnormality (OR 4.42; 95% CI 1.27-15.34), severe sepsis/septic shock (OR 5.76; 95% CI 2.57-12.89) and agr group III (OR 0.27; 0.10-0.75). Vancomycin MIC ≥1.5 mg/L was not independently associated with death during hospital nor was it related to secondary end points. No other genotype variables were independently associated with in-hospital death.

CONCLUSIONS

This is the first prospective study to assess the impact of S. aureus phenotype and genotype. Phenotype and genotype provided no additional predictive value beyond conventional clinical characteristics. No evidence was found to justify therapeutic decisions based on vancomycin MIC for either methicillin-resistant or methicillin-susceptible S. aureus.

Comparison of the clinical course of Clostridium difficile infection in glutamate dehydrogenase-positive toxin-negative patients diagnosed by PCR to those with a positive toxin test

OBJECTIVES

To evaluate the potential role of PCR-based assays in the over-diagnosis of Clostridium difficile infection (CDI) by using a validated diagnostic algorithm in daily clinical practice.

METHODS

We performed a retrospective cohort study evaluating all C. difficile-positive stool samples identified at our institution during a 12-month period, to compare outcomes and recurrence rates between patients with a positive enzyme immunoassay (EIA) for both glutamate dehydrogenase (GDH) and toxin A/B ('toxin-positive group'), with those with GDH-positive, toxin-negative samples in whom the diagnosis was made by a positive PCR-based assay ('toxin^-/PCR⁺ group'). Medical records were reviewed by two independent investigators blinded to the mode of diagnosis.

RESULTS

We analysed 231 first CDI episodes (106 (45.8 %) in the 'toxin-positive group' and 125 (54.1%) in the 'toxin^-/PCR⁺ group'). Both groups had similar baseline characteristics. Patients in the 'toxin-positive group' presented more frequently with a severe/severe complicated form than those in the 'toxin^-/PCR⁺ group' (36 (33.9%) versus 24 (19.2%); p 0.011) and had more recurrences (27 (25.5%) versus 9 (7.2%); p 0.001). Diagnosis of CDI based on a GDH/toxin-positive EIA independently predicted severe/severe-complicated course (adjusted OR 2.11; 95% CI 1.06-4.22; p 0.033) and recurrence (adjusted OR 3.79; 95% CI 1.65-8.69; p 0.002). There were no differences in all-cause mortality (12.3% versus 12.0%; p 0.95) or CDI-attributable mortality (4.7% versus 4.8%; p 0.93).

CONCLUSIONS

Toxin-positive patients were more likely to have severe-complicated forms of CDI and recurrences. Nevertheless, CDI-related complications may still occasionally occur among toxin-negative patients diagnosed by PCR, which stresses the need for individualized clinical evaluation.

Should Asymptomatic Bacteriuria Be Systematically Treated in Kidney Transplant Recipients? Results From a Randomized Controlled Trial

The indication for antimicrobial treatment of asymptomatic bacteriuria (AB) after kidney transplantation (KT) remains controversial. Between January 2011 and December 2013, 112 KT recipients that developed one episode or more of AB beyond the second month after transplantation were included in this open-label trial. Participants were randomized (1:1 ratio) to the treatment group (systematic antimicrobial therapy for all episodes of AB occurring ≤24 mo after transplantation [53 patients]) or control group (no antimicrobial therapy [59 patients]). Systematic screening for AB was performed similarly in both groups. The primary outcome was the occurrence of acute pyelonephritis at 24-mo follow-up. Secondary outcomes included lower urinary tract infection, acute rejection, Clostridium difficile infection, colonization or infection by multidrug-resistant bacteria, graft function and all-cause mortality. There were no differences in the primary outcome in the intention-to-treat population (7.5% [4 of 53] in the treatment group vs. 8.4% [5 of 59] in the control group; odds ratio [OR] 0.88, 95% confidence interval [CI] 0.22-3.47) or the per-protocol population (3.8% [1 of 26] in the treatment group vs. 8.0% [4 of 50] in the control group; OR 0.46, 95% CI 0.05-4.34). Moreover, we found no differences in any of the secondary outcomes. In conclusion, systematic screening and treatment of AB beyond the second month after transplantation provided no apparent benefit among KT recipients (NCT02373085).

Progressive increase of resistance in Enterobacteriaceae urinary isolates from kidney transplant recipients over the past decade: narrowing of the therapeutic options

BACKGROUND

Antibiotic resistance is an emerging phenomenon in kidney transplantation (KT).

METHODS

We compared species distribution and antimicrobial susceptibility patterns in 1052 isolates from urine cultures obtained in 2 different cohorts of kidney transplant recipients in a single center (Cohort A: 189 patients undergoing KT between January 2002 and December 2004 [336 isolates]; Cohort B: 115 patients undergoing KT between January 2011 and December 2013 [716 isolates]).

RESULTS

Asymptomatic bacteriuria accounted for most of the isolates (86.9% in Cohort A and 92.3% in Cohort B). Klebsiella pneumoniae (9.5% vs. 15.6%), Pseudomonas aeruginosa (1.8% vs. 7.9%), and Enterobacter cloacae (0.6% vs. 3.1%) were significantly more common in Cohort B. The isolation of K. pneumoniae in Cohort B was associated with the occurrence of acute pyelonephritis (9.8% of all K. pneumoniae isolates vs. 2.8% of the remaining uropathogens; P = 0.001). Non-susceptibility rates among Enterobacteriaceae in Cohort B were higher for every class of antibiotics (P ≤ 0.003) with the exception of fosfomycin. Compared to Cohort A, significant increases were seen in isolates from Cohort B for multidrug-resistant (MDR) (43.9% vs. 67.8%, respectively; P = 0.001), extended-spectrum beta-lactamase (ESBL)-producing (6.6% vs. 26.1%; P = 0.001), and carbapenemase-producing Enterobacteriaceae strains (0.0% vs. 5.0%; P = 0.001). Such differences were mostly attributable to K. pneumoniae (as 54.5% and 13.4% of isolates in Cohort B were ESBL-producing and carbapenemase-producing, respectively). MDR isolates were responsible for 69.1% of episodes of symptomatic urinary tract infection in Cohort B.

CONCLUSION

The increase in resistance rates among Enterobacteriaceae uropathogens is significant and may have an effect on KT programs.