[Removal of Cryptosporidium and Giardia in drinking water treatment in a Tuscan area]. / Rimozione di Cryptosporidium e Giardia in impianti di potabilizzazione dell'Area Vasta Fiorentina.

Five drinking water treatment plants in the Tuscan area, differing in relation to the treatments employed, were monitored for the presence of Cryptosporidium and Giardia (oo)cysts in order to estimate their removal capacity of each works. Twenty-eight water samples (16 from inflow raw water and 12 from outflow drinking water) were analysed during the one-year survey. The US EPA 1623 method was used, obtaining, according to the PHLS quality control system, a recovery rate of 51.3 +/- 22.9% for Cryptosporidium oocysts and 48.8 +/- 20.7% for Giardia cysts. The results showed that both the protozoa were present in surface raw waters: Cryptosporidium in 62.5% and Giardia in 87.5% of the samples. Considering the outflow drinking waters, the removal capacity varied from 100% in the technologically more complex plant (which supplies most of the area), to at least 90% in the remaining four plants, where less complex treatments are carried out. The occurrence of (oo)cysts was not associated with seasonality, turbidity or Clostridium perfringens (Cl. perfringens seems to be related with Cryptosporidium oocysts in surface raw waters; in this respect, our legislation states that the protozoa have to be searched for whenever a water sample is positive for Cl. perfringens). We confirmed the validity of the US-EPA 1623 method in assessing and managing the risk associated with waterborne protozoa, thus a valid tool to safeguard the population from exposure to such pathogens.

Performance of horizontal subsurface-flow treatment wetlands in fecal bacteria removal.

This work evaluated sub-surface flow (SSF) constructed wetlands and activated sludge plant efficiency in pathogen removal. The two were also compared. The removal of fecal bacteria (total coliforms, fecal coliforms, fecal streptococci) was evaluated. Analysis was carried out during one year by determining the amount of bacteria in the inflow and the outflow of four systems: three SSF systems (two were pilot plants and one a fully operating plant) and an activated sludge plant. MPN techniques were used to determine the quantity-value of the microorganisms. Percentages of fecal bacteria removal in wetlands systems were as good as (and sometimes better than) those recorded in the activated sludge plant. Optimal values of these bacteria were obtained in the outflow of the post-treatment pilot plant: very high bacterial removal percentages (>99%) were recorded. SFS constructed wetlands are a valid solution for the final treatment of the outflow of existing plants.

Nontuberculous mycobacteria in hospital water systems: application of HPLC for identification of environmental mycobacteria.

Nontuberculous mycobacteria (NTM), ubiquitous in water environments, are increasingly recognized as nosocomial pathogens. Our study reports a one-year survey of the water system of two hospitals, A and B, in a small town near Florence, Italy. NTM were found throughout the study period in both settings, but B showed a significantly higher mycobacterial load. Mycobacterium gordonae and Mycobacterium fortuitum were the most frequent species isolated. Identification was carried out by conventional techniques and by high performance liquid chromatography (HPLC) analysis of cell wall mycolic acids. HPLC profiling could be used as a first-choice method for identification of environmental mycobacteria.

Determination of carbonyl compounds in water by derivatization-solid-phase microextraction and gas chromatographic analysis.

The solid-phase microextraction (SPME) technique was evaluated for the determination of 23 carbonyl compounds in water. The carbonyl compounds in water were derivatized with omicron-(2,3,4,5,6-pentafluorobenzyl)-hydroxylamine hydrochloride (PFBHA), extracted with SPME from liquid or headspace and analyzed by GC with electron capture detection (GC-ECD). The effects of agitation techniques and the addition of salt (NaCl) on extraction, the absorption-time and absorption-concentration profiles were examined. The precision of the SPME technique for the determination of carbonyl compounds was evaluated with spiked bidistilled water, ozonated drinking water, and rain water. The relative standard deviations obtained from different spiked water matrix were similar, and in the range of 5.7-21.1%. The precision can be further improved by using an internal standard. With 4 ml of water sample, the limits of detection for most of the tested carbonyl compounds using liquid or headspace SPME-GC-ECD were similar and in the range of 0.006-0.2 micrograms/l, except for glyoxal and methylglyoxal, which showed low sensitivity when using headspace SPME. In the analysis of an ozonated drinking water sample, the SPME techniques gave comparable results to those of the conventional liquid-liquid extraction method.

Anaesthetic management of caesarean section in a parturient with acute myelodysplastic syndrome.

A 34-year-old pregnant woman developed a myelodysplastic syndrome during pregnancy which resulted in a refractory anaemia and an extreme thrombocytopenia. The report describes the anaesthetic management of elective caesarean section and successful childbirth in this patient. Following replacement therapy with packed red cells and platelets, general anaesthesia was used for the procedure.

Dissolution of Barium from Barite in Sewage Sludges and Cultures of Desulfovibrio desulfuricans.

High concentrations of total barium, ranging from 0.42 to 1.58 mg(middot)g(sup-1) (dry weight) were found in sludges of two sewage treatment plants near Florence, Italy. Barium concentrations in the suspended matter decreased as redox potential values changed from negative to positive. An anoxic sewage sludge sample was aerated, and 30% of the total barium was removed in 24 h. To demonstrate that barium was solubilized from barite by sulfate-reducing bacteria, a strain of Desulfovibrio desulfuricans was used to study the solubilization of barium from barite under laboratory conditions. During cell growth with different concentrations of barite from 0.01 to 0.3 g(middot)liter(sup-1) (the latter is the MIC) as the only source of sulfates in the cultures, the D. desulfuricans strain accumulated barium up to 0.58 (mu)g(middot)mg(sup-1) (dry weight). Three times the quantity of barium was dissolved by bacteria than in the uninoculated medium (control). The unexpectedly low concentration of soluble barium (1.2 mg of Ba(middot)liter(sup-1)) with respect to the quantity expected (109 mg of Ba(middot)liter(sup-1)), calculated on the basis of the free H(inf2)S evolved from the dissimilatory reduction of sulfate from barite, was probably due to the formation of other barium compounds, such as witherite (BaCO(inf3)) and the transient species barium sulfide (BaS). The D. desulfuricans strain, growing on barite, formed visible aggregates. Confocal microscopy analysis showed that aggregates consisted of bacteria and barite. After 3 days of incubation, several autofluorescent crystals surrounded by a dissolution halo were observed. The crystals were identified as BaS by comparison with the commercial compound.

Single umbilical artery: analysis of Doppler flow indices and arterial diameters in normal and small-for-gestational age fetuses.

In this study we examined the value of Doppler flow measurements of the umbilical artery in distinguishing normal fetuses from those with single umbilical artery, and studied the Doppler flow differences and the compensatory arterial dilatation in appropriate (AGA) and small-for-gestational-age (SGA) fetuses with single umbilical artery. The Doppler flow indices (pulsatility index, S/D ratio) and the arterial diameters were prospectively and serially measured in 26 and 15 fetuses with single umbilical artery and without congenital malformations, respectively. Longitudinal changes in Doppler flow indices in normal and SGA fetuses with single umbilical artery are comparable, and are within normal reference ranges for three-vessel cords; there is a fairly constant widening of the single umbilical artery throughout gestation and a mean increase in size of about 1 mm over that found in normal cords from 20 weeks onward. In fetuses with single umbilical artery at mid-gestation, an umbilical artery diameter of more than 4 mm occurred in only 5/15 cases and is therefore not a reliable criterion for single umbilical artery screening prior to 26 weeks of gestation. Doppler flow measurements in normal and SGA fetuses with single umbilical artery are not significantly different from normal fetuses. Compensatory arterial dilatation may prevent fetuses with single umbilical artery from becoming growth retarded.

Normal pregnancy in primary alveolar hypoventilation treated with nocturnal nasal intermittent positive pressure ventilation.

Nocturnal nasal intermittent positive pressure ventilation (NIPPV) is increasingly used to treat chronic respiratory failure in a wide variety of conditions (myopathies, Ondine's curse, kyphoscoliosis, etc.) and allows a normal everyday life. Some of these diseases affect women of childbearing age. We report on a young woman suffering from primary alveolar hypoventilation, who presented with limitation of daytime activities, severe oxygen desaturation during sleep, polycythaemia and pulmonary hypertension. These abnormalities completely reversed after a few months of NIPPV applied through a nasal mask. Whilst under ventilatory assistance during sleep, she had an uneventful pregnancy and delivery of a normal baby. We suggest that in selected patients requiring NIPPV, pregnancy can be contemplated with a reasonable level of safety both for the mother and the child, provided that adequate mechanical ventilatory assistance during sleep is maintained throughout pregnancy.