Long-term contamination of sink drains by carbapenemase-producing Enterobacterales in three intensive care units: characteristics and transmission to patients.

This study aimed to describe the contamination of sink drains (SDs) with carbapenemase-producing Enterobacterales (CPE) in three intensive care units (ICUs), and to assess the risk of transmission to hospitalized patients. All SDs were sampled monthly for CPE screening by culture. Rectal screening for CPE carriage was conducted weekly for hospitalized patients. CPE were isolated from 22% of SD samples. Some SDs remained colonized with the same strain for several months. No CPE acquisition occurred among hospitalized patients during the study. Certain strategies, such as systematic sampling of SDs in ICUs for screening for contamination by CPE, should be discouraged apart from during outbreaks.

High prevalence of closely-related Acinetobacter baumannii in pets according to a multicentre study in veterinary clinics, Reunion Island.

Our objective was to study the carriage of Acinetobacter baumannii (AB) in pets in Reunion Island (RI), a French territory in Indian Ocean. Overall, 138 pets were sampled (rectum, mouth, wounds if applicable) in 9 veterinary clinics (VC). The prevalence of AB carriage was 6.5% (95%CI; 2.4, 10.6) and 9 carriers were identified from 4 VC. Hospitalization in a VC and antimicrobial treatment administered within the 15 preceding days were significantly associated with AB carriage (P<0.01 and P<0.05, respectively). Despite the VC in which animals have been sampled were located all around RI, most isolates (8/9) were closely-related (>90% similarity by pulsed-field gel electrophoresis). Additional studies are needed to improve the understanding about interactions between the different reservoirs of AB in RI.

Assessment of new chemical disinfectants for HBV virucidal activity in a cell culture model.

Several new chemical disinfectants were processed for Hepatitis B virus (HBV) virucidal activity in a cell culture model. A pooled HBV infected human plasma with 10(10.4) HBV DNA copies/mL was treated with the tested disinfectant. It was then subjected, for three days at several dilutions, to cell culture using the human hepatoma cell line, HepG2, with 4% polyethyleneglycol and 3 mM sodium butyrate. Thirty-seven assays were performed on 12 products, with up to 3 concentrations and 3 time exposures for each product tested. The mean viral titre without disinfectant was 10(5.18) infectious units per mL. Our results showed that products all four hand rubs examined, two of the three surface disinfectants and two of the three instrument disinfectants were highly active whatever concentrations and time exposures, reducing viral times by factors of 10(3)-10(4). However, other products such as one of the surface disinfectants was only active at concentrations above 0.5% for 15 min. Similarly the skin disinfectant, one of the instrument disinfectants and the hand wash agent (diluted to 50%) were less or not active (of <10(3) fold reduction). This is the first study using a cell culture model to assess virucidal activity against HBV of new disinfectants. It showed that most 9/12 products were active by either HBs antigen alteration (8/9) or probable envelope disruption (1/9). Further studies are in progress using this model to assess the activity of other chemical disinfectants such as peracetic acid against HBV.

Inactivation of hepatitis B virus in plasma by hospital in-use chemical disinfectants assessed by a modified HepG2 cell culture.

Because of the difficulties of the chimpanzee model and the genetic differences using the duck model, we developed a cell culture method to measure human hepatitis B virus (HBV) inactivation in vitro. Pooled HBV-infected human plasma that had been exposed to a disinfectant was left in contact for three days with a cell culture of the human hepatoma cell line, HepG2, with 4% polyethyleneglycol and 3 mM sodium butyrate. The mean log10 of the viral titre of unexposed plasma was 4.87 infectious units per mL. Our results showed that 1% glutaraldehyde, sodium hypochlorite at 4700 ppm free chlorine and an iodophor-detergent disinfectant containing 3.6% povidone-iodine reduced viral titres by factors exceeding 10(3)-10(4). However, sodium hypochlorite at 1000 ppm free chlorine had minimal activity and povidone-iodine at 9, 5 and 3.6% had no measurable activity (less than 10-fold reduction). This is the first study using a cell culture model to assess disinfectant activity against HBV. It demonstrates more rapidly than the chimpanzee model that glutaraldehyde and sodium hypochlorite, using standard concentrations and exposure times compatible with clinical practice, were highly active against HBV. However, unexpectedly for an enveloped virus, we found no antiviral activity for iodine in the absence of detergent.