Outbreak of carbapenem-resistant Providencia rettgeri in a tertiary hospital.

The emergence of resistance to multiple antimicrobial agents in pathogenic bacteria is a significant public health threat, as there are limited effective antimicrobial agents for infections caused by multidrug-resistant (MDR) bacteria. Several MDR bacteria are now frequently detected. Carbapenem resistance in Enterobacteriaceae is often plasmid mediated, necessitating stringent infection control practices. Wedescribe an outbreak of carbapenem-resistant Providencia rettgeri involving 4 patients admitted to intensive care and high-care units at a tertiary hospital. Clinical and demographic characteristics of 4 patients with carbapenem-resistant P. rettgeri were documented. All P. rettgeri isolated in these cases had a carbapenem-resistant antibiogram, with resistance to imipenem, ertapenem and meropenem. These cases could be epidemiologically linked. A multiprong approach, simultaneously targeting antibiotic stewardship, universal precautions and appropriate transmission-based precaution practices, is integral to prevention and control of nosocomial infections.

Fluoride release from four visible light-cured orthodontic adhesive resins.

Decalcification of enamel during fixed orthodontic appliance treatment remains a problem. This study determined the in vitro fluoride (F) release from four light-cured orthodontic adhesives since cariostatic potential of such adhesives is related to their F releasing ability. Two nonfluoride and two fluoride-containing adhesives were tested. By means of the potentiometric analytical method, the F release of each resin was determined daily for 7 days and thereafter weekly for a month and then monthly until week 85. The data were analyzed with Kruskal-Wallis, Mann-Whitney, and Wilcoxon matched-pairs tests. The F release of all the resins were characterized by an initial burst of F release during the first day, followed by a tapering down in magnitude. FluorEver (MacroChem, Billerica, Mass.) outperformed the other adhesives in all aspects of F release and continued to release F for up to 85 weeks. Fluorapatite formation resulting from F release from orthodontic adhesives could be more advantageous in reducing decalcification during fixed appliance treatment than other preventive modalities.

The strength of two reinforced glass ionomer materials.

Preformed stainless steel crowns survive longer than multi-surface amalgams on deciduous molars. With the use of reinforced glass ionomers the bulk of the lost tooth structure can be replaced and the stainless steel crown cemented simultaneously. The purpose of this study was to compare two glass ionomer cements with regard to their shear bond strength (SBS) to the dentine of extracted primary molars and to their diametral tensile strength (DTS). The results showed that Vitremer was significantly (p < 0.01) stronger (DTS:x = 19.21; SBS:x = 7.63) than Ketac-Silver (DTS:x = 8.94; SBS:x = 2.92).

The fluoride concentration in the drinking water of towns in the Transvaal, Orange Free State and Natal.

In previous studies the water fluoride content of the larger cities in South Africa, and smaller towns in the Cape Province were recorded. This project was extended to include smaller towns (500 or more inhabitants) in the Transvaal, Orange Free State and Natal. Drinking water was collected in polypropylene containers and the fluoride content determined potentiometrically. The information obtained made it possible to compile a table setting out the fluoride content of the drinking water in these smaller towns. The study confirms a previous observation that water from boreholes has the highest (p < 0.05), and fountains the lowest fluoride content.

Two outbreaks of fluorosis in cattle and sheep.

Two outbreaks of fluorosis in cattle and sheep were investigated in the Northern Transvaal. The animals exhibited severe dental lesions, lameness and exostoses. Plasma fluoride concentrations were high and there was an inversion of the albumin/globulin ratio. Alkaline phosphatase activity was elevated. Drinking water from boreholes contained excessive amounts of fluoride and upon irrigation, pastures were also contaminated with fluoride.

The fluoride content of enamel as a diagnostic aid in fluorosis.

This study was undertaken to compare the fluoride content ([F]) of sound and hypoplastic enamel of dogs' teeth for use as a diagnostic aid for fluorosis. Enamel biopsies (0.5N HClO4; 15 seconds; 3.143 mm2) were conducted on macroscopically sound areas of the middle buccal surfaces of the right upper canine teeth. The [F], and the calcium concentrations of the etching solutions were determined using the potentiometric analytical method and the flame spectrophotometer respectively. Depth of etch (DOE) was calculated. The results of the study showed that the higher [F] in the hypoplastic enamel when compared to that of sound enamel (p > 0.05), was more a result than a cause of the hypoplasia. In this study, the [F] of the enamel was used successfully to exclude the possibility of fluorosis.

[Fluoride status of a community and fluoride concentration in its drinking water]. / Fluoriedstatus van'n gemeenskap met'n lae fluoriedioonkonsentrasie in die drinkwater.

Despite the low fluoride (F) content of the drinking water (less than 0.05 mg/l), an optimum to above optimum daily F intake was shown for the community in Tshikundamalema (Republic of Venda, Southern Africa). In order to evaluate the biological availability of fluoride in the diet, the assimilation of the fluoride ion in enamel was tested. Six age groups (selected according to WHO criteria) consisting of 10 individuals each were used in the study. Enamel biopsies (2N HCl0(4); 3,143 mm2; 8 seconds) were conducted on the mid-labial surfaces of the central maxillary incisors. The fluoride concentrations of the etching solutions were analyzed according to the potentiometric analytical method. The calcium concentrations were determined by means of a flame spectrophotometer. The F content of the outer 10 microns in the enamel of the community was examined in relation to the total daily intake of fluoride for the community. The results obtained from the study showed that, the F content of the enamel of the community (x = 1,133 pg/micrograms; 10 microns depth of etch) correlated with the F intake of the community (x = 3.15 mg F/day). Thus the F content of the diet was biologically available to the body. However, between age groups and sexes, no correlation could be found between the fluoride status and the fluoride intake.

[In vitro uptake of fluoride from South African fluoride gel dentifrices]. / Die in vitro fluoriedopname van 'n Suid Afrikaanse-vervaardigde oppervlaksfluoriedgel.

An increasingly difficult situation in obtaining imported products has led to the development of a locally-manufactured topical fluoride gel. In order to evaluate the anticariogenic potential of the gel an in vitro study was conducted to compare the fluoride (F) uptake into the enamel from the locally-manufactured gel with that of two overseas products. Sound, unerupted third molar teeth were used in the study. One half of the buccal surface of each tooth was used as a control and the remaining half for conducting the experiment. Enamel biopsies (0.5 N HCLO4 3,143 mm2; 15 sec) were conducted prior to the F treatment (control halves) as well as 24 hours after F treatment (experimental halves). The fluoride concentrations ([F]) of the etching solutions were analyzed according to the potentiometric analytical method. The calcium concentrations were determined by means of a flame spectrophotometer. The [F] of the control halves of the teeth were used as a reference to determine the actual F uptake in the experimental halves after F treatment. The results obtained from the study showed that the teeth treated with the locally-manufactured F gel, revealed a significant uptake of fluoride in the enamel as well as an increased resistance to acid dissolution. Only one of the imported products showed a statistically significant higher fluoride uptake than the acidulated South African manufactured phosphate fluoride gel. There was a favourable overall comparison of the locally manufactured F gel with that of the overseas products.

[Fluoride intake in a community with low fluoride concentration in drinking water]. / Fluoriedinname van'n gemeenskap met 'n lae fluoriedioonkonsentrasie in die drinkwater.

The fluoride content of representative samples of the drinking water and diet of the inhabitants of Tshikundamalema (Republic of Venda, southern Africa) was determined according to the potentiometric method of fluoride analysis. The mean daily intake of fluoride of the inhabitants was compared with the recommended daily intake of fluoride, as advocated by the Mayo Clinic (USA). Despite the low fluoride ion concentration ([F-]) of the drinking water (less than 0.05 mg/l), there exists an optimum to above optimum (3,54-5,32 mg F-) daily intake of fluoride for the adults in Tshikundamalema. The main source of fluoride intake was from beer and green leafy vegetables. The intake of fluoride for the children in Tshikundamalema is sub-optimal (0.598 mg F-/day).

[Semi-microanalytical method of fluoride determination in enamel biopsies]. / Semi-mikro-analitiese metode vir fluoriedbepaling in glasuurbiopsies.

When making use of potentiometric micro-analytical methods in fluoride determination, only a portion of the lantanium fluoride (LaF) crystal of the fluoride electrode is employed. Although there is no difference in sensitivity when using either the total surface or a part of the surface of the LaF crystal, there are advantages in using the total surface of the crystal. For the purpose of utilizing these advantages to a maximum, a semi-micro-analytical method of fluoride determination was developed. A perspex electrode container with a specimen capacity of 50 microliters was designed and constructed in order to bring the total surface of the LaF crystal into contact with the testing solution. Due to the inexpensive and simple design of the containers there are practically no restrictions on the number that could be employed. The solution obtained from a single enamel biopsy could be used for at least two or three analyses. The results obtained by employing the technique described, showed that the method is precise and accurate. The semi-microanalytical method offers an alternative to the micro-analytical method of fluoride determination in enamel biopsies.