Hand Disinfection ; standards ; Hand Hygiene ; methods ; Humans ; Infection Control ; methods

Disinfectants ; analysis ; Disinfection ; Drinking Water ; analysis ; Environmental Monitoring ; methods

In-depth knowledge of disinfection and sterilization is a key component of infection control. Sterilization completely removes a spore, whereas disinfection cannot. Disinfectants are classified as oxidants and non-oxidants. The decision regarding which method to apply is based on Spaulding's classification. In this article, disinfection and sterilization are thoroughly reviewed, and extensive information from basic to practical points is discussed.
Classification ; Disinfectants ; Disinfection* ; Infection Control ; Methods ; Oxidants ; Spores ; Sterilization*

In-depth knowledge of disinfection and sterilization is a key component of infection control. Sterilization completely removes a spore, whereas disinfection cannot. Disinfectants are classified as oxidants and non-oxidants. The decision regarding which method to apply is based on Spaulding's classification. In this article, disinfection and sterilization are thoroughly reviewed, and extensive information from basic to practical points is discussed.
Classification ; Disinfectants ; Disinfection* ; Infection Control ; Methods ; Oxidants ; Spores ; Sterilization*

Experimental model of Pseudomonas aeruginosa biofilm was established in vitro by using biofilm reactor. The aim of this study was evaluating the removal effect of two kinds of water flowing through bactericide resin on Pseudomonas aeruginosa biofilm, and exploring the effectiveness of continuous treatment with low concentration disinfection factor on dental unit waterlines. The experimental group selected 1-2 mg/L iodinated resin (IR) filtered water and bromined hydantoin resin (BHR) filtered water with the control group selecting the sterile distilled water. Biofilms were treated by using the immersion method for 3, 7, 10, 20, and 40 days. Total viable count (TVC) and laser confocal microscopy method (CLSM) were selected to evaluate the biofilm removal effect. The result of TVC showed that in group IR, the bacterial clearance after the treatment of 3, 7, 10, and 20 days was lower than 99.9% and unqualified. The bacterial clearance after the treatment of 40 days was 99.9%,which is qualified. In group BHR, it was lower than 99.9% and unqualified after the treatment of 3, 7, and 10 days. It was and 99.99%, 100.00% after the treatment of 20, 40 days, respectively. The result of CLSM showed that before treatment, Pseudomonas aeruginosa biofilm showed a sheet and mass distribution. The bacterial coverage was 19.24%±1.97%. The proportion of viable bacteria was 93.91%±1.39%, and the biofilm matrix coverage was 17.69%±1.11%. After 20 days of treatment, the biofilm was decreased in the IR group, with the biofilm bacterial coverage reducing to 6.77%±1.61%, the proportion of live bacteria reducing to 54.85%±5.65%, and the biofilm matrix coverage reducing to 2.41%±0.85%.There was significant difference from the pre-treatment and the control (F=359.996,P<0.001). No biofilm-like structure was found in the BHR group. After 40 days of treatment, there was still a small amount of biofilm matrix residue in the IR group, with no bacterial coverage observed. The biofilm matrix coverage was 0.67%±0.47% (F=1 021.373,P<0.001). No biofilm-like structure was found in the BHR group. In conclusion, the continuous application of BHR filter water has more advantages in killing microorganisms in biofilms, removing live and dead bacteria and biofilm matrix in biofilms. Treatment water containing corresponding low concentration disinfection factors can play an important role in the field of biofilm control in dental unit waterlines.
Humans ; Disinfection/methods* ; Pseudomonas aeruginosa ; Biofilms ; Water/pharmacology*

Experimental model of Pseudomonas aeruginosa biofilm was established in vitro by using biofilm reactor. The aim of this study was evaluating the removal effect of two kinds of water flowing through bactericide resin on Pseudomonas aeruginosa biofilm, and exploring the effectiveness of continuous treatment with low concentration disinfection factor on dental unit waterlines. The experimental group selected 1-2 mg/L iodinated resin (IR) filtered water and bromined hydantoin resin (BHR) filtered water with the control group selecting the sterile distilled water. Biofilms were treated by using the immersion method for 3, 7, 10, 20, and 40 days. Total viable count (TVC) and laser confocal microscopy method (CLSM) were selected to evaluate the biofilm removal effect. The result of TVC showed that in group IR, the bacterial clearance after the treatment of 3, 7, 10, and 20 days was lower than 99.9% and unqualified. The bacterial clearance after the treatment of 40 days was 99.9%,which is qualified. In group BHR, it was lower than 99.9% and unqualified after the treatment of 3, 7, and 10 days. It was and 99.99%, 100.00% after the treatment of 20, 40 days, respectively. The result of CLSM showed that before treatment, Pseudomonas aeruginosa biofilm showed a sheet and mass distribution. The bacterial coverage was 19.24%±1.97%. The proportion of viable bacteria was 93.91%±1.39%, and the biofilm matrix coverage was 17.69%±1.11%. After 20 days of treatment, the biofilm was decreased in the IR group, with the biofilm bacterial coverage reducing to 6.77%±1.61%, the proportion of live bacteria reducing to 54.85%±5.65%, and the biofilm matrix coverage reducing to 2.41%±0.85%.There was significant difference from the pre-treatment and the control (F=359.996,P<0.001). No biofilm-like structure was found in the BHR group. After 40 days of treatment, there was still a small amount of biofilm matrix residue in the IR group, with no bacterial coverage observed. The biofilm matrix coverage was 0.67%±0.47% (F=1 021.373,P<0.001). No biofilm-like structure was found in the BHR group. In conclusion, the continuous application of BHR filter water has more advantages in killing microorganisms in biofilms, removing live and dead bacteria and biofilm matrix in biofilms. Treatment water containing corresponding low concentration disinfection factors can play an important role in the field of biofilm control in dental unit waterlines.
Humans ; Disinfection/methods* ; Pseudomonas aeruginosa ; Biofilms ; Water/pharmacology*

OBJECTIVETo develop and evaluate the efficiency of air purification and sterilization instrument based on nano-sized TiO(2) photocatalytic technique.

METHODSThe nano-sized TiO(2) photocatalytic air purification and sterilization instrument was designed and a sample had been prepared. The sterilization efficiencies for E.coli and Klebsiella by the nano-sized TiO(2) photocatalytic instrument and ultraviolet (UV) were measured in closed labs. The on-site efficiency of the instrument was evaluated, too.

RESULTSThe nano-sized TiO(2) photocatalytic air purification and sterilization instrument was composed of five units: rough filter, nano-sized TiO(2) photocatalytic unit, activated carbon fiber filter, negative ion generator, and programmed control unit. The E.coli killing rates by the nano-sized TiO(2) photocatalytic instrument were 76.0%, 81.8%, 77.5%, and 80.7% at 30, 60, 90, and 120 minutes, respectively. There was no significant difference between the E.coli killing rates of the instrument and UV (P > 0.05), except the 120 minutes timepoint. The Klebsiella killing rates by the instrument were 78.4%, 79.5%, 67.3%, and 58.5% at 30, 60, 90, and 120 minutes, respectively. The Klebsiella killing efficiencies of the instrument at 30 and 60 minutes were better than that of UV (P < 0.01). There was no significant difference between the Klebsiella killing efficiencies of the instrument and UV (P > 0.05).

CONCLUSIONThe air sterilization efficiency of the nano-sized TiO(2) photocatalytic instrument should be equivalent or better as compared with the UV. This instrument might be used for the air purification and sterilization of the public locations.

Air Pollution ; prevention & control ; Decontamination ; methods ; Disinfection ; methods ; Nanostructures ; Photochemistry ; Titanium

OBJECTIVETo introduce synergetic inactivation of microorganisms in drinking water by short-term free chlorination for less than 15 minutes followed by monochloramination.

METHODSIndicator microorganisms such as Escherichia coli, Staphylococcus aureus, Candida albicans, and spores of Bacillus subtilis were used to assess the efficiency of sequential chlorination and free chlorination.

RESULTSThe sequential chlorination was more efficient in inactivating these microorganisms than free chlorination, indicating that synergy was provided by free chlorine and monochloramine. Ammonia addition time, temperature and pH had influences on this synergy.

CONCLUSIONSThe possible mechanism of this synergy might involve three aspects: free chlorine causing sublethal injury to microorganisms and monochloramine further inactivating them; different ability of free chlorine and monochloramine to penetrate and inactivate microorganism congeries; and higher concentration of residual chlorine in sequential chlorination than in free chlorination.

Chloramines ; chemistry ; pharmacology ; Chlorine ; chemistry ; Disinfection ; methods ; Halogenation ; Water ; chemistry ; Water Microbiology ; Water Purification ; methods

The objective of the investigation was to study the application of ultrasound reactor technology (USRT) as a disinfectant for reduction of fungi from sewage effluent. Fungi are carbon heterotrophs that require preformed organic compounds as carbon sources. USRT is an attractive means to improve water quality because of the system simplicity and no production of toxic by-products. An ultrasound reactor produces strong cavitation in aqueous solution causing shock waves and reactive free radicals by the violent collapse of the cavitation bubble. These effects should contribute to the physical disruption of microbial structures and inactivation of organisms. There was significant reduction in fungal growth, with decreased fungal growth with increasing USRT. In this study, ultrasound irradiation at a frequency of 42 kHz was used to expose suspensions of fungi to evaluate the disinfection efficacy of the ultrasound reactor. Also, this study showed that in this system more than 99% reduction of sewage fungi was achieved after 60 min.
Colony Count, Microbial ; Disinfection ; methods ; Fungi ; growth & development ; isolation & purification ; Sewage ; microbiology ; Ultrasonics

OBJECTIVETo study the effects of 4 different methods for disinfection of simple breathing vesicles and microbial residue.

METHODSThe disinfection tests were divided into 4 groups: G1 group (43 cases) with 500 mg/L chlorine dioxide spray, G2 group (28 cases) with alcohol spray, G3 group (47 cases) with 50 mg/L trichloroisocyanuric acid (TCCA) immersion, and G4 group (46 cases) with 50 mg/L chlorine dioxide solution immersion. After 30 min of disinfection, each group was examined by bacterial culture and colony count. The residual bacteria were identified and typed.

RESULTSThe 4 methods showed significant differences in bacterial colony count (P<0.001). The rate of bacterial residue was 0% in G1 group, 53.6% in G2 group, 27.7% in G3 group, and 21.7% in G4 group, showing significant differences between the 4 groups (P<0.001). The residual bacteria included antibiotic-resistant common opportunistic pathogen such as Pseudomonas aeruginosa, Acinetobacter baumannii and Staphylococcus haemolytic.

CONCLUSIONSDisinfection with 500 mg/L chlorine dioxide spray is the best for simple breathing vesicles. Prolonged immersion in TCCA may lead to the growth of drug-resistant pathogens in the breathing vesicles.

Bacteria ; isolation & purification ; Colony Count, Microbial ; Disinfection ; methods ; Drug Resistance, Bacterial ; Ventilators, Mechanical