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.

[French recommendations on control measures to reduce the infectious risk in immunocompromised patients]. / Quelles mesures pour maîtriser le risque infectieux chez les patients immunodéprimés ? Recommandations formalisées d'experts.

The increase use of immunosuppressive treatments in patients with solid cancer and/or inflammatory diseases requires revisiting our practices for the prevention of infectious risk in the care setting. A review of the literature by a multidisciplinary working group at the beginning of 2014 wished to answer the following 4 questions to improve healthcare immunocompromised patients: (I) How can we define immunocompromised patients with high, intermediate and low infectious risk, (II) which air treatment should be recommended for this specific population? (III) What additional precautions should be recommended for immunocompromised patients at risk for infection? (IV) Which global environmental control should be recommended? Based on data from the literature and using the GRADE method, we propose 15 recommendations that could help to reduce the risk of infection in these exposed populations.

Practices of infectious control management during neutropenia: A survey from 149 French hospitals.

OBJECTIVE OF THE STUDY: Neutropenic patients represent a growing and fragile population in our hospitals. Numerous treatments induce neutropenia in haematology wards and elsewhere. Although strict isolation is recommended during post-haematopoietic stem cell transplantation neutropenia, this may not be the current practice in other situations. In this study, our objective was to analyse what protective measures are applied in neutropenic patients in a French survey. MATERIELS AND METHODS: A questionnaire was sent out to infection control teams of 400 public and private French hospitals to enquire about their local recommendations regarding infection prevention in neutropenic patients. RESULTS: Among the 166 (41%) responders, 134 (81%) managed neutropenic patients. All of the centres recommended protective isolation for neutropenic patients. However, only 46 (34%) had clearly defined patients warranting specific isolation measures in terms of the level of neutropenia. All of the centres recommended several barrier measures, but these were highly variable according to the type of air treatment in the wards (note that only 72% of haematology wards are equipped with air treatment). Gowns, gloves, masks, hats and shoe covers were respectively recommended in 128 (95%), 79 (59%), 132 (98%), 87 (65%), and 34 (25%) of the establishments. Surprisingly, the recommendations vary both among hospitals and within the same hospital among different clinical wards. CONCLUSION: In conclusion, protective measures for neutropenic patients are applied variably and urgently require a consensus to homogenize practices.

Contribution of tap water to patient colonisation with Pseudomonas aeruginosa in a medical intensive care unit.

This study examined tap water as a source of Pseudomonas aeruginosa in a medical intensive care setting. We prospectively screened specimens of patients, tap water and hands of healthcare workers (HCWs) over a six-month period in a 16-bed medical intensive care unit. Molecular relatedness of P. aeruginosa strains was investigated by pulsed-field gel electrophoresis. A total of 657 tap water samples were collected from 39 faucets and 127 hands of HCWs were sampled. P. aeruginosa was found in 11.4% of 484 tap water samples taken from patients' rooms and in 5.3% of 189 other tap water samples (P<0.01). P. aeruginosa was isolated from 38 patients. Typing of 73 non-replicate isolates (water samples, hands of HCWs and patients) revealed 32 major DNA patterns. Eleven (52.4%) of the 21 faucets were contaminated with a patient strain, found before isolation from tap water in the corresponding room in nine cases, or from the neighbouring room in two cases. Among seven P. aeruginosa strains isolated from HCW hands, the genotype obtained was the same as that from the last patient they had touched in six cases, and in the seventh with the last tap water sample used. More than half of P. aeruginosa carriage in patients was acquired via tap water or cross-transmission. Carriage of P. aeruginosa by patients was both the source and the consequence of tap water colonisation. These results emphasise the need for studies on how to control tap water contamination.

[Reservoirs and transmission of Pseudomonas aeruginosa in intensive care unit]. / Réservoirs et transmission de Pseudomonas aeruginosa en réanimation médicale.

OBJECTIVE: The authors had for aim to study reservoirs and transmission of Pseudomonas aeruginosa in an intensive care unit. DESIGN: A 6-month prospective descriptive study was made on water samples, samples from hands of health care workers, and clinical samples. P. aeruginosa strains were compared by pulsed-field gel electrophoresis. RESULTS: Among the 211 patients hospitalized during the study, 14 (6.6%) were infected by P. aeruginosa. Out of 494 water samples, 80 were contaminated by P. aeruginosa. The regularly disinfected water taps were more rarely contaminated than the others (P<10(-5)). Out of 140 hand samples, one showed contamination from an infected patient. CONCLUSIONS: aeruginosa cross transmission was observed during this study. We should follow strict hygienic precautions such as wearing gloves and performing thorough alcoholic rub disinfection. Water taps are often contaminated and require regular disinfection.

[Is length of stay in the recovery room a risk factor for cross infections?]. / Le séjour en salle de surveillance postinterventionnelle peut-il être à l'origine de transmissions croisées?

OBJECTIVE: To assess cross contamination for patients at the time of their stay in the recovery room (RR). STUDY DESIGN: Prospective study. PATIENTS AND METHODS: A prospective survey over 3 weeks with 75 adult patients admitted to RR after thoracic or neck surgery. Samples for bacterial analysis were systematically taken from all patients before they left the operating theatre and just before discharge of RR (nose-throat and skin adjacent to the surgical wound). During this period, hand's health care workers (HCW) and environmental surfaces were sampled. RESULTS: There were 3 groups of patients: endoscopy (41%), thoracic surgery (39%). And thyroidectomy (20%), 392 samples were analysed. Potentially pathogenic floras were found on the admission for 25 patients and at discharge for 31 patients. A pathogenic flora was detected at discharge in 13 patients, whereas none was found at admission in RR. These patients were principally in the thyroidectomy group and their stay in RR was longer than 20 minutes. There is no significant difference concerning the nosocomial risk between 3 groups. Pathogenic flora was found in 19% of HCW (8 of 42). CONCLUSION: Cross contamination can exist in recovery room and educative measures are to be taken regarding handwhashing, isolation precautions and environmental cleaning.

Investigation of an outbreak due to Alcaligenes xylosoxydans subspecies xylosoxydans by random amplified polymorphic DNA analysis.

In 1999, over a 3-week period, Alcaligenes xylosoxydans subsp. xylosoxydans was isolated from five blood cultures and one cerebrospinal fluid specimen from five children hospitalized in a pediatric hematology ward as well as from two respiratory therapy devices of two children hospitalized in an intensive care unit. The infection control unit of the hospital conducted an epidemiological investigation and identified a detergent-disinfectant solution as the source of contamination. Conventional biochemical tests, antimicrobial susceptibility tests and random amplified polymorphic DNA (RAPD) fingerprinting were used to compare clinical and environmental isolates. RAPD analysis proved to be more discriminant than biotyping or antibiotyping in this context and identified the common source of the outbreak.

Electronic ventilator temperature sensors as a potential source of respiratory tract colonization with Stenotrophomonas maltophilia.

Stenotrophomonas maltophilia (S. maltophilia) is an important cause of nosocomial infection among ventilated and immunocompromised patients, and among patients receiving broad-spectrum antimicrobials. We report a cluster of patients in a surgical intensive care unit who were colonized or infected with S. maltophilia. An epidemiological investigation was initiated after surveillance data revealed that eight patients were culture-positive from sputum for S. maltophilia in the preceding month. Review of respiratory care procedures revealed that when mechanical ventilators were serviced between patients, the electronic temperature probes used with servo-controlled humidifiers were wiped with inadequate disinfection. We collected cultures of case-patient room surfaces, sinks and ventilator equipment. S. maltophilia was recovered from room surfaces, ventilator expiratory circuits and a temperature sensor which had been kept in ambient air after disinfection. Patients and environmental isolates were examined by RAPD-PCR. Three clinical isolates and one environmental isolate had the same profile, which suggests cross-contamination or common source exposure. The outbreak was controlled by adequate disinfection of the temperature sensors. No single epidemic strain was identified but several observations support the conclusion that the temperature probes contributed to the outbreak.