Hyperthermia Prevents In Vitro and In Vivo Biofilm Formation on Endotracheal Tubes.

There is currently an urgent need to find new strategies to tackle antimicrobial resistance and biofilm-related infections. This study has two aims. First, we evaluated the in vitro efficacy of hyperthermia in preventing biofilm formation on the surfaces of polyvinyl chloride discs. Second, we assessed the in vivo efficacy of hyperthermia in preventing biofilm formation in endotracheal tubes (ETTs) of a rabbit model. For the in vitro studies, nine clinical extensively drug-resistant/multidrug-resistant Gram-negative isolates of Acinetobacter baumannii, Klebsiella pneumoniae, and Pseudomonas aeruginosa and three clinical methicillin-resistant Staphylococcus aureus strains were studied. For biofilm formation, an adhesion step of 30 or 90 min followed by a growth step of 24 h were performed with application of one, two, and three pulses at 42°C for 15 min each pulse after the adhesion step. For the in vivo studies, New Zealand rabbits were intubated with ETTs previously colonized with K. pneumoniae or P. aeruginosa strains, and three pulses at 42°C for 15 min were applied after the adhesion step. The application of three pulses at 42°C for 15 min each pulse was needed to achieve the prevention of the in vitro biofilm formation of 100% of the tested strains. The application of heat pulses in a rabbit intubation model led to biofilm prevention of 85% against two K. pneumoniae strains and 80% against two P. aeruginosa strains compared to the control group. Hyperthermia application through pulses at 42°C could be a new nonantibiotic strategy to prevent biofilm formation in ETTs. IMPORTANCE Biofilm-producing microorganisms are considered medically crucial since they cause 80% of the infections that occur in the human body. Medical devices such as endotracheal tubes (ETTs) can act as a reservoir for pathogens providing the surface to which microorganisms can adhere and cause biofilm-associated infections in critically ill patients. This biofilm has been related with the development of ventilator-associated pneumonia (VAP), with an incidence of 8 to 28%, a mortality rate up to 17% and its associated high extra costs. Although some VAP-preventive measures have been reported, they have not demonstrated a significant reduction of VAP incidence. Therefore, we present a new nonantibiotic strategy based on hyperthermia application to prevent biofilm formation inside ETTs. This technology could reduce VAP incidence, intubation duration, hospital and intensive care unit (ICU) length stays, and mortality rates. Consequently, this could decrease the antibiotics administered and influence the impact of antibiotic resistance in the ICU.

Ceftolozane/tazobactam for the treatment of XDR Pseudomonas aeruginosa infections.

PURPOSE: The aim of this study was to evaluate the effectiveness of ceftolozane/tazobactam (C/T) for treating extensively drug-resistant Pseudomonas aeruginosa (XDR-PA) infections, and to analyze whether high C/T dosing (2 g ceftolozane and 1 g tazobactam every 8 h) and infection source control have an impact on outcome. METHODS: Retrospective study of all consecutive patients treated with C/T for XDR-PA infection at a tertiary referral hospital (November 2015-July 2017). Main clinical and microbiological variables were analyzed. RESULTS: Thirty-eight patients were included. Median age was 59.5 years and Charlson Comorbidity Index was 3.5. Fourteen (36.8%) patients had respiratory tract infection, six (15.8%) soft tissue, and six (15.8%) urinary tract infection. Twenty-three (60.5%) received high-dose C/T and in 24 (63.2%) C/T was combined with other antibiotics. At completion of treatment, 33 (86.8%) patients showed clinical response. At 90 days of follow-up, 26 (68.4%) achieved clinical cure, and 12 (31.6%) had clinical failure because of persistent infection in one patient, death attributable to the XDR-PA infection in four, and clinical recurrence in seven. All-cause mortality was 5 (13.2%). Lower C/T MIC and adequate infection source control were the only variables significantly associated with clinical cure. CONCLUSIONS: C/T should be considered for treating XDR-PA infections, with infection source control being an important factor to avoid failure and resistance.

A Cohort Study of Risk Factors That Influence Empirical Treatment of Patients with Acute Pyelonephritis.

The aim of the current study was to compare community-acquired acute pyelonephritis (CA-APN) with health care-associated acute pyelonephritis (HCA-APN), describe the outcomes, and identify variables that could predict antimicrobial susceptibility. We conducted an observational study that included all consecutive episodes of acute pyelonephritis (APN) in adults during 2014 at a Spanish university hospital. From each episode, demographic data, comorbidities, clinical presentation, microbiological data, antimicrobial therapy, and outcome were recorded. A multivariable logistic regression model was performed to define the variables associated with antimicrobial resistance. A total of 607 patients, 503 (82.9%) with CA-APN and 104 (17.1%) with HCA-APN, were included in the study. Patients with HCA-APN were older than patients with CA-APN (70.4 versus 50.6 years; P < 0.001) and had higher rates of previous urinary tract infections (UTIs) (56.5% versus 24.5%; P < 0.001) and previous antibiotic use (56.8% versus 22.8%; P < 0.001). Escherichia coli was more frequently isolated from patients with CA-APN than from patients with HCA-APN (79.9% versus 50.5%; P < 0.001). The rates of resistance of Escherichia coli strains from CA-APN patients versus HCA-APN patients were as follows: amoxicillin-clavulanic acid, 22.4% versus 53.2% (P = 0.001); cefuroxime, 7.7% versus 43.5% (P = 0.001); cefotaxime, 4.3% versus 32.6% (P < 0.001); ciprofloxacin, 22.8% versus 74.5% (P < 0.001); and co-trimoxazole, 34.5% versus 58.7% (P = 0.003). The site of acquisition, recurrent UTIs, and previous antibiotic use were independent risk factors for antimicrobial resistance. Relapse rates were significantly higher when definitive antimicrobial treatment was not adequate (37.1% versus 9.3% when definitive antimicrobial treatment was adequate; P < 0.001). Our study reflects the rise of resistance to commonly used antibiotics in acute pyelonephritis. In order to choose the adequate empirical antibiotic therapy, risk factors for resistance should be considered.

Invasive pneumococcal disease in patients infected with HIV: still a threat in the era of highly active antiretroviral therapy.

We studied all human immunodeficiency virus (HIV)-infected patients with invasive pneumococcal disease who received their diagnosis during 1996-2002 to investigate the incidence of this disease in the highly active antiretroviral therapy era and to study the influence of CD4 lymphocyte count on the clinical presentation and outcome of disease. The overall incidence of invasive pneumococcal disease was 11.3 cases per 100,000 person-years in adult patients without known HIV infection and 677 cases per 100,000 person-years in HIV-infected patients. This incidence remained stable over the study period. Clinical presentation, severity of illness, and number of recurrent episodes were similar in patients with CD4+ cell counts of >200 or < or =200 cells/ microL. Patients receiving trimethoprim-sulfamethoxazole (TMP-SMZ) were more likely to present with TMP-SMZ-resistant pneumococci than were those who were not receiving this agent (76.7% vs. 43.6%; P=.007). The mortality rate was high (21%).

Efficacy of ampicillin combined with ceftriaxone and gentamicin in the treatment of experimental endocarditis due to Enterococcus faecalis with no high-level resistance to aminoglycosides.

OBJECTIVE: This study tests the usefulness of ceftriaxone combined with ampicillin as an alternative to ampicillin plus gentamicin for the treatment of experimental endocarditis due to Enterococcus faecalis without high-level resistance to aminoglycosides. It also determines whether adding ceftriaxone to ampicillin and gentamicin increases the effectiveness against experimental enterococcal endocarditis resulting from E. faecalis. METHODS: Animals with catheter-induced endocarditis were infected intravenously with 108 cfu of the EF91 strain of E. faecalis and were treated for 3 days with ampicillin 2 g every 4 h administered as 'human-like' (H-L) pharmacokinetics, plus gentamicin 1 mg/kg every 8 h H-L, or ceftriaxone 2 g every 12 h H-L alone or combined with gentamicin 6 mg/kg every 24 h administered subcutaneously. RESULTS: The results of therapy for experimental endocarditis resulting from EF91 showed that the combination of ampicillin plus ceftriaxone was as effective as ampicillin plus gentamicin. The triple combination did not improve on the overall efficacies of the two-drug combinations. CONCLUSIONS: Because of its lower nephrotoxicity, ampicillin plus ceftriaxone may be a useful alternative therapy for E. faecalis endocarditis in selected patients.