Metagenomic analysis of microbial communities and antibiotic resistance genes in spoiled household chemicals.

Many outbreaks of Burkholderia cepacia complex (Bcc) infections are associated with contaminations in personal care products (PCPs). This study aimed to analyze a collection of Bcc isolates in PCPs and assess the susceptibility of preservatives, including dimethoxy dimethyl hydantoin (DMDMH), methylisothiazolinone-chloromethylisothiazolinone (MIT/cMIT), and methyl 4-hydroxybenzoate (MH). The Bcc isolates collected during the 3-year (2015-2017) study period were further examined by biochemical identification system, phylogenetic analysis based on recA nucleotide sequences, and multilocus sequence typing analysis. Preservatives susceptibility testing of Bcc bacteria were evaluated by minimum inhibitory concentration and minimum bactericidal concentration. A total of seven distinct sequence types (STs) were identified, which belonged to four different Bcc species: Burkholderia cenocepacia (ST621, ST258, and novel ST), Burkholderia lata (ST339 and ST336), Burkholderia contaminans (ST482), Burkholderia cepacia (ST922). For DMDMH and MH, the maximum permitted concentrations according to the safety specification of cosmetics (0.6% and 0.4%) were able to inhibit or kill all Bcc strains, but 40% of Bcc isolates could survive at higher than maximum permitted concentrations of MIT/cMIT (of a mixture in the ratio 3:1 of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one). The PCPs contamination of Bcc strains should be given more attention by manufacturers because of its diversity in molecular epidemiology and its low susceptibility to preservatives such as MIT/cMIT.

Burkholderia Cepacia Complex in Personal Care Products: Molecular Epidemiology and Susceptibility to Preservatives.

The invention discloses a method for detecting the particulate matter removal rate of an air purifier. The concentrations of PM1.0 particles in test chambers of a experimental group running a purifiermodel machine to be tested and a blank control group without the purifier model machine to be tested are tested respectively after the initial time and a same action time, and the effective removal rate of the particles is calculated according to measured data to finally obtain the particle purification effect of the purifier model machine to be tested. The method uses PM1.0 particles as a test index to reduce the test workload, can also judge the test performance of the purifier in a constant and unified time, and meanwhile judges the test result with a reduction rate or an effective removalrate, thereby simplifying the operation steps, improving the detection efficiency, allowing consumers to intuitively judge the ability to remove particles of the purifier in a specific time and space, and being more acceptable to consumers.

Wen Xia

Papers

Burkholderia Cepacia Complex in Personal Care Products: Molecular Epidemiology and Susceptibility to Preservatives.

Method for detecting particulate matter removal rate of air purifier