Antibiotics associated with acquisition of carbapenem-resistant Pseudomonas aeruginosa in ICUs: a multicentre nested case-case-control study.

Background: Carbapenem-resistant Pseudomonas aeruginosa (CRPA) strains are involved in severe infections, mostly in ICUs. Exposure to antibiotics other than carbapenems may be associated with isolation of CRPA; therefore, we aimed to identify those antibiotics using the case-case-control study design. Methods: A case-case-control study was conducted in 2015 in a prospective multicentre cohort that included 1808 adults hospitalized in 2009 in 10 French ICUs. Patients were screened for P. aeruginosa at admission to the ICU and then weekly. Cases were patients with CRPA and patients with carbapenem-susceptible P. aeruginosa (CSPA) isolation. Controls were patients without P. aeruginosa isolation, matched with each case according to centre, length of stay and hospitalization period. Effects of antibiotic exposure were explored, after adjusting for prior treatment with carbapenems and confounding factors comprising colonization pressure with two logistic regression models. The two models were compared to identify specific risk factors for CRPA isolation. Results: Fifty-nine CRPA, 83 CSPA and 142 controls were compared. In adjusted multivariable analyses, exposure to carbapenems and to antibiotics belonging to the group of ß-lactams inactive against P. aeruginosa were independent risk factors for CRPA isolation (OR, 1.205; 95% CI, 1.079-1.346 and OR, 1.101; 95% CI, 1.010-1.201, respectively). Conversely, exposure to ß-lactams active against P. aeruginosa was an independent protective factor for CSPA isolation (OR, 0.868; 95% CI, 0.772-0.976). Conclusions: Besides carbapenem exposure, exposure to ß-lactams inactive against P. aeruginosa was a specific risk factor for CRPA isolation. Clinicians should counterweigh the potential benefits of administering these antibiotics against the increased risk of CRPA infection.

Contributory conditions for unexpected COVID-19 cases and nosocomial COVID-19 infection cases identified from systematic investigation in a French University Hospital.

INTRODUCTION: Nosocomial case (NC) of COVID-19 infections is a challenge for hospitals. We report the results of a seven-month prospective cohort study investigating COVID-19 patients to assess unexpected cases (UC) (no COVID-19 precautionary measure application since admission) and NC. PATIENTS AND METHODS: Investigation by an infection control team of 844 patients with COVID-19 infection hospitalized for more than 24 hours (cases). RESULTS: A total of 301 UC were identified (31% after contact tracing) with a total of 129 contact patients, and 27 secondary cases for 59 of them. In geriatric wards, 50% of cases were UC. NC represented 18% of cases (37% in geriatric wards), mainly identified after contact tracing of wandering cases. CONCLUSION: A rapid infection control response is essential to contain nosocomial transmission, along with detailed contact tracing and screening policy. Dealing with wandering elderly patients remain challenging for HCWs.

Carbapenem stewardship program in a French university children's hospital.

INTRODUCTION: Carbapenems, last-resort antibiotics, are widely used as first-line treatment in patients carrying extended-spectrum beta-lactamases (ESBL) Enterobacteriaceae, including in a pediatric setting. We aimed to implement an antibiotic stewardship program (ASP) to improve the use of carbapenems. METHODS: We implemented an ASP at the Bordeaux Children's University Hospital with 6-month audits on prescribing practice before and after an intervention (revision of antibiotic treatment protocols, a half-day educational session with feedback of the first study period). The number of carbapenem prescriptions was analyzed and two criteria were used to assess conformity of the indication for carbapenem prescription and conformity of the reassessment. A logistic regression was used to assess the overall compliance of carbapenem prescriptions over the two periods adjusted for ESBL carriage. RESULTS: A total of 57 patients were included with 37 carbapenem prescriptions before the intervention and 23 after. Overall carbapenem consumption decreased from 0.54 prescriptions per 100 admissions to 0.32 (p = 0.06). Conformity increased during the study for indication (46-87%, p = 0.004) and for reassessment (48-78%, p = 0.04) and was significantly associated with the second study period, after adjustment for ESBL carriage. CONCLUSION: Our intervention contributed to a significant improvement in the compliance to indications for carbapenem indication and in the reassessment of the prescription.

Exogenous acquisition of Pseudomonas aeruginosa in intensive care units: a prospective multi-centre study (DYNAPYO study).

BACKGROUND: Pseudomonas aeruginosa remains one of the most common nosocomial pathogens in intensive care units (ICUs). Although exogenous acquisition has been widely documented in outbreaks, its importance is unclear in non-epidemic situations. AIM: To elucidate the role of exogenous origin of P. aeruginosa in ICU patients. METHODS: A chronological analysis of the acquisition of P. aeruginosa was performed using samples collected in 2009 in the DYNAPYO cohort study, during which patients and tap water were screened weekly. Molecular relatedness of P. aeruginosa isolates was investigated by pulsed-field gel electrophoresis. Exogenous acquisition was defined as identification of a P. aeruginosa pulsotype previously isolated from another patient or tap water in the ICU. FINDINGS: The DYNAPYO cohort included 1808 patients (10,402 samples) and 233 water taps (4946 samples). Typing of 1515 isolates from 373 patients and 375 isolates from 81 tap water samples identified 296 pulsotypes. Analysis showed exogenous acquisition in 170 (45.6%) of 373 patients. The pulsotype identified had previously been isolated from another patient and from a tap water sample for 86 and 29 patients, respectively. The results differed according to the ICU. CONCLUSION: Exogenous acquisition of P. aeruginosa could be prevented in half of patients. The overall findings of this survey support the need for studies on routes of transmission and risk assessment approach to better define how to control exogenous acquisition in ICUs.