Exposure of Metal Oxide Nanoparticles on the Bioluminescence Process of Pu- and Pm-lux Recombinant P. putida mt-2 Strains.

Comparison of the effects of metal oxide nanoparticles (NPs; CuO, NiO, ZnO, TiO2, and Al2O3) on different bioluminescence processes was evaluated using two recombinant (Pm-lux and Pu-lux) strains of Pseudomonas putida mt-2 with same inducer exposure. Different sensitivities and responses were observed according to the type of NPs and recombinant strains. EC50 values were determined. The negative effects on the bioluminescence activity of the Pm-lux strain was greater than for the Pu-lux strains for all NPs tested. EC50 values for the Pm-lux strain were 1.7- to 6.2-fold lower (corresponding to high inhibition) than for Pu-lux. ZnO NP caused the greatest inhibition among the tested NPs in both strains, showing approximately 11 times less EC50s of CuO, which appeared as the least inhibited. Although NPs showed different sensitivities depending on the bioluminescence process, similar orders of EC50s for both strains were observed as follows: ZnO > NiO, Al2O3 > TiO2 > CuO. More detailed in-depth systematic approaches, including in the field of molecular mechanisms, is needed to evaluate the accurate effect mechanisms involved in both bioluminescence metabolic processes.

Evaluation of the Efficacy and Superiority of Different Vial Rubber Closure Disinfection Techniques.

Contamination of sterile products has caused significant adverse outcomes in patients, including death. Limited research has been conducted on the efficacy and/or superiority of sterile isopropyl alcohol disinfection techniques of rubber stopper surfaces in sterile compounding. The objective of this evaluation was to investigate the efficacy and/or superiority between the following three disinfecting techniques of vial rubber tops when utilizing sterile isopropyl alcohol wipes: Intervention 1) three swipes back and forth using the same surface; Intervention 2) three swipes in a unidirectional manner using the same surface; Intervention 3) three swipes in a unidirectional manner using a different side of wipe with each swipe. The rubber stopper surfaces of 90 vials were contaminated with bacteria. Thirty vials were disinfected with each assigned technique, swabbed after drying, and plated. After plates were incubated for 48 hours, colonies were quantified, and the different techniques compared. When comparing the varying disinfection techniques to the positive control, Intervention 1 and Intervention 3 techniques showed statistical significance (P=0.00). The Intervention 2 technique showed no difference in colony counts from the positive control (P=0.259). Comparing the different techniques side by side, both Intervention 1 and Intervention 3 techniques were statistically different from the Intervention 2 technique (P=0.027, P=0.00). There was no statistical significance noted between the Intervention 1 and Intervention 3 disinfecting techniques (P=0.141). Disinfecting vials with three swipes in one direction with a different surface of the sterile alcohol wipe or disinfecting vials with a back and forth motion three times is superior to either not disinfecting the vial or disinfecting the vial with three swipes in one direction using the same surface of the sterile alcohol wipe during sterile compounding.

Does current cefazolin dosing achieve adequate tissue and blood concentrations in obese women undergoing cesarean section?

BACKGROUND: Prophylactic administration of antibiotics preceding cesarean delivery is the most effective measure taken for preventing postpartum infection. While obese women are at greater risk for infection than non-obese women, evidence-based recommendations for modifying dosing in these women are limited. OBJECTIVES: The purpose of this study was to determine whether obese women undergoing cesarean delivery similarly reach adequate cefazolin concentrations within tissue and blood when weighing <120kg and dosed 2g versus weighing ≥120kg and dosed 3g. STUDY DESIGN: We prospectively studied women ≥18 years old with body mass index ≥30kg/m2 who underwent scheduled cesarean delivery with singleton pregnancy from August 2014 through March 2016. Women were dosed with 2g and 3g of cefazolin for body weights <120kg and ≥120kg, respectively. Samples of subcutaneous adipose tissue (following skin incision and before skin closure), myometrial tissue, fetal cord blood, and maternal blood were collected to assess whether cefazolin concentrations were adequate, i.e., at/above the minimum inhibitory concentration (MIC). Concentrations, based on inhibition zones for Streptococcus sanguinis, were calculated per gram of solid tissue and milliliter of blood. For all sample types, log-transformed concentrations were compared between dosage groups. Using a range of published MICs (1-8µg/mL or µg/g), odds ratios, describing differential odds of falling below the MIC between dosage groups, were also computed. RESULTS: Women who received 2g (n=65) versus 3g (n=19) of cefazolin did not significantly differ by maternal or gestational age, race/ethnicity, pre-operative hemoglobin, estimated blood loss, fluid administration, duration of surgery, or timing of sample collections relative to cefazolin administration (Ps>0.05). Dosage groups also did not differ in cefazolin concentration (median [interquartile range]) within adipose tissue following skin incision (5.30µg/g [3.00-9.60] vs. 6.35µg/g [3.90-8.40]; P=0.551), adipose tissue before skin closure (4.45µg/g [2.78-7.25] vs. 6.90µg/g [2.60-10.6]; P=0.342), myometrial tissue (13.1µg/g [8.60-19.6] vs. 15.7µg/g [10.8-21.7]; P=0.116), or maternal blood (41.6µg/mL [26.3-57.0] vs. 45.3µg/mL [36.7-68.3]; P=0.143). However, cord blood concentrations differed significantly (19.5µg/mL [13.7-28.5] vs. 27.9µg/mL [15.8-39.4]; P=0.032), and, in 3 of 5 sample types, group concentrations differed at the dosing cut-point of 120kg (Ps<0.02). Within the range of MICs considered, differences in the odds of concentration inadequacy were not detected between dosage groups for any sample type. Across all patients, inadequate concentrations in one or more solid tissue types were observed in 1.19%, 17.9%, 59.5%, and 86.9% of patients, given the MICs of 1µg/g, 2µg/g, 4µg/g and 8µg/g, respectively. In adipose tissues, specifically, and both dosage groups, mean concentrations were significantly lower than the MIC of 8µg/g (Ps<0.03). Concentrations in one or both blood sample types were inadequate for only 8.33% of patients, given the 8-µg/mL MIC. CONCLUSIONS: Adequate cefazolin concentrations were achieved in blood for the majority of our patients. However, concentration adequacy was not achieved in solid tissue for a nearly equally large proportion of patients. Larger scale studies for determining modified protocols for dosing and applying MICs are warranted.

Biosensors of bacterial cells.

Biosensors are devices which utilize both an electrical component (transducer) and a biological component to study an environment. They are typically used to examine biological structures, organisms and processes. The field of biosensors has now become so large and varied that the technology can often seem impenetrable. Yet the principles which underlie the technology are uncomplicated, even if the details of the mechanisms are elusive. In this review we confine our analysis to relatively current advancements in biosensors for the detection of whole bacterial cells. This includes biosensors which rely on an added labeled component and biosensors which do not have a labeled component and instead detect the binding event or bound structure on the transducer. Methods to concentrate the bacteria prior to biosensor analysis are also described. The variety of biosensor types and their actual and potential uses are described.

A novel molecular pattern for methicillin-resistant Staphylococcus aureus in Milwaukee, WI clinical isolates.

Methicillin-resistant Staphylococcus aureus is a significant problem in healthcare settings around the world. To effectively track different strains, we used a number of genetic procedures. In this study, 252 clinical isolates from the Milwaukee, WI, area were analyzed by the multiplex polymerase chain reaction (PCR) method to determine which of the described types were present. Most strains were categorized into one of the known groups, although types III and IIIA strains were not found. An unusual variant was found in 17% of the samples. This variant (v1) contains an 800-base pair amplimer that was created from a unique configuration of 2 primers from different sets in the multiplex PCR procedure. Although superficially similar to a type I pattern, sequencing of the amplimer demonstrated that it is identical to a sequence from the USA300 strain, a type IV strain. It is suggested that this variant may have resulted from acquisition of an IS431 element near the dcs region. There is potential for misidentification of strains because of slight genetic alterations such as this one. Statistical analysis using a chi(2) contingency table demonstrated that amoxicillin/clavulanic acid resistance was significantly lower in types I and IA when compared with the other types, whereas erythromycin resistance was significantly lower in type I when compared with other types. However, there was not a significant difference for any of the new variants.