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E. LEONI, G. DE LUCA, P.P. LEGNANI, R. SACCHETTI, S. STAMPI AND F. ZANETTI. 2004. Aims: An evaluation was made of the prevalence of Legionella species in hot water distribution systems in the city of Bologna (Italy) and their possible association with bacterial contamination (total counts and Pseudomonadaceae) and the chemical characteristics of the water (pH, Ca, Mg, Fe, Mn, Cu, Zn and Total Organic Carbon, TOC). Methods and Results: A total of 137 hot water samples were analysed: 59 from the same number of private apartments, 46 from 11 hotels and 32 from five hospitals, all using the same water supply. Legionella species were detected in 40AE0% of the distribution systems, L. pneumophila in 33AE3%. The highest colonization was found in the hot water systems of hospitals (93AE7% of samples positive for L. pneumophila, geometric mean: 2AE4 · 10 3 CFU l )1 ), followed by the hotels (60AE9%, geometric mean: 127AE3 CFU l )1 ) and the apartments with centralized heating (41AE9%, geometric mean: 30AE5 CFU l )1 ). The apartments with independent heating systems showed a lower level of colonization (3AE6% for Legionella species), with no evidence of L. pneumophila. Correlation analysis suggests that copper exerts an inhibiting action, while the TOC tends to favour the development of L. pneumophila .N o statistically significant association was seen with Pseudomonadaceae, which were found at lower water temperatures than legionellae and in individual distribution points rather than in the whole network. Conclusions: The water recirculation system used by centralized boilers enhances the spreading of legionellae throughout the whole network, both in terms of the number of colonized sites and in terms of CFU count. Significance and Impact of the Study: Differences in Legionella colonization between types of buildings are not due to a variation in water supply but to other factors. Besides the importance of water recirculation, the study demonstrates the inhibiting action of copper and the favourable action of TOC on the development of L. pneumophila.

Aims: The aim of this study was to compare the efficiency of peracetic acid with that of chlorine dioxide in the disinfection of wastewater from a sewage treatment plant (serving about 650 000 inhabitants) that has been using peracetic acid as a disinfectant since 1998. Methods and Results: A total of 23 samplings were made, each consisting of three samples: from secondary effluent, effluent disinfected with 2 mg l−1 of peracetic acid and effluent disinfected with 2·2 mg l−1 of chlorine dioxide (contact time 20 min). For each sample, measurements were made of the heterotrophic plate count at 36°C, total and faecal coliforms, Escherichia coli, enterococci, pH, suspended solids and chemical oxygen demand (COD). During the first phase of the experiment the peracetic acid was seen to be less efficient than chlorine dioxide. To improve the disinfectant action a system of mechanical agitation was added which led to a greater efficiency in the inactivation of bacteria of faecal origin. Conclusions: Both products were found to be influenced by the level of microbial contamination, the amount of suspended solids and COD but not by the pH of the effluent before disinfection. The immediate mixing of the wastewater and disinfectant caused a greater reduction in enterococci. Significance and Impact of the Study: Since peracetic acid was seen to produce a high abatement of micro-organisms, it can be considered as a valid alternative to chlorine dioxide in the disinfection of wastewaters.

Aims: Evaluation of the efficiency of peracetic acid in the disinfection of wastewater in a large treatment plant. Methods and Results: Over a period of 18 months 30 sample collections were made, each consisting of three samples taken from: raw incoming sewage, secondary effluent (after 10–12 h) and secondary effluent disinfected with 1·5–2 mg l–1 of peracetic acid (contact time: 20 min). Total coliforms and Escherichia coli declined from 107 MPN 100 ml–1 in the raw sewage to 102 in the disinfected effluent and the enterococci fell from 106 MPN 100 ml–1 to 702 MPN 100 ml–1. The reduction of bacteria increased with the rise in temperature and decreased with the rise in BOD5. Conclusions: Disinfection with peracetic acid reduced levels of faecal contamination by 97%, thus attaining the limit recommended by current Italian law (Escherichia coli≤ 5000 MPN 100 ml–1) for discharge into surface waters. Significance and Impact of the Study: The process of disinfection with peracetic acid is easier to manage than other more common methods and the tests performed confirm that from the bacteriological point of view good results can be obtained for urban effluents.

This study evaluated the incidence of Legionella pneumophila in dental unit water samples and investigated how the occurrence of these bacteria may be related to some physical, chemical and bacteriological characteristics of the water. The samples were taken from the incoming tap water, oral rinsing cup, air-water syringe, ultrasonic scaler, and the turbine of 23 dental units of private and public institutions. Apart from L. pneumophila (serogroup 1 and 3) isolated in 22 out of the 101 (21.8%) water samples tested, two other species were found: L. bozemanii and L. dumoffii. The highest densities and frequency of L. pneumophila were observed in the water coming into the units and in the dental units of public institutions. A negative association between L. pneumophila and 36 degrees C and 22 degrees C heterotrophic total plate counts and other gram-negative bacteria was found. An inverse association between the concentration of L. pneumophila and water temperature was also observed. The values of pH and total hardness did not show any significant difference in the L. pneumophila-positive and -negative dental unit waters. Finally, the chemical oxygen demand (COD) and residual chlorine were found to correlate positively with L. pneumophila.

The presence of thermophilic campylobacters and Arcobacter was investigated in four types of sewage sludge taken from the treatment plant in Bologna (Italy): primary, activated, thickened and anaerobically digested sludge. Campylobacter jejuni and Campylobacter coli . were more numerous during the March-September period and were found only in primary sludge (22.7%) with mean counts of 278 MPN/g dry matter and 1403 MPN/g dry matter respectively. Arcobacter butzleri were found in all types of sludge with frequencies of 80% in activated and thickened sludges and 41% in digested sludges. They were more numerous in the spring/summer period with peaks in April, May, June and September. They were less sensitive to anerobic digestion than fecal bacteria, probably due to their microaerophilic growth properties. However, since they are found in anaerobically digested sludges at mean values of 7649 MPN/g dry matter the land application of digested sludges may cause high risks of infection.

Thermophilic campylobacters and Arcobacter butzleri were looked for in 57 manually shelled egg samples and 130 raw meat samples. No bacteria were found in the egg samples, but they were, however, found in 16.1% of meat samples with a frequency varying from 2.4% (pork sausage) to 37.5% (poultry). A total of 21 strains were identified, one belonging to Arcobacter butzleri (pork) and 20 to Campylobacter. The most common species was C. jejuni ( 16 20 ) followed by C. coli ( 4 20 ) and in both species biotype I was the most frequently found. Regarding the methods employed for the isolation of bacteria, no substancial difference was seen between the three media (Butzler, CCDA and Preston) although CCDA medium gave better results than Butzler and Preston media. The variable which had the most influence was the incubation temperature. A higher number of strains was obtained at 42 °C than at 37 °C.

A study was carried out on alcohol intake among the students of the Schools for Trained Nurses in the province of Bologna by means of an anonymous especially prepared questionnaire. The series consisted of 1077 subjects: 753 females and 324 males aged between 16 and 40. 68.2% of males and 56.8% of females drank wine, l'81.3% of males and 61.8% of females drank beer and 65.3% of males and 46.2% of females drank spirits. While beer was the most popular drink, wine was on average drank in greater quantity. Alcohol intake was significantly related to sex (higher among males), area of origin (South) and cigarette smoking. The risk attributable to alcohol abuse are well known to almost all of the sample, above all those in the 2nd and 3rd years of their course. Nevertheless their alcohol consumption was not particularly different from that of students attending other High Schools. Regarding the sources, of their information about the risks, the 'mass media' was more quoted by the oldest students while 'family' was given by the younger students; the Nursing School was more often mentioned by both sexes in the 2nd and 3rd year of course. No relation however was found between the students knowledge of risks and actual consumption.

The investigation was carried out by evaluating the microbiological characteristics of the water before and after treatment with Er:YAG laser and turbine. The study was carried out in 2 dental surgeries. In both cases the laser and dental units were served by two independent circuits, fed by the same potable tap water. Samples were taken from the water supplying and the water leaving the turbine and laser before and after treatment on the same patient. Total heterotrophic plate count was measured at 36 degrees C and at 22 degrees C, and the presence of Staphylococcus species and non-fermenting Gram negative bacteria was investigated. Bacterial contamination was found within the circuit, especially in the laser device. Pseudomonas aeruginosa was detected in only 1 sample of supply water, in 11.1 % and in 19.4 % of the samples from the turbine and the laser respectively. No evidence of Staphylococcus aureus was found. The contamination of supply water was low, whereas that of the water leaving the handpieces of the 2 devices was high, especially in the laser. Attention should be paid to the control of the water leaving laser devices, given the increasingly wide use of such instruments in dental treatment exposed to risk of infection.

The aim of the study was to assess the efficiency of low doses of peracetic acid against viral and bacterial indicators in wastewater and to evaluate if the treatment allows regulatory requirements to be satisfied. A total of 31 samplings were carried out, each involving the collection of secondary effluent and of effluent disinfected with 1.2 or 1.5 mg l(-1) of peracetic acid (contact time 20 minutes). In each sample were measured: somatic coliphages, F-specific RNA bacteriophages, Escherichia coli, total and faecal coliforms, enterococci. Peracetic acid disinfection showed significant differences between the reductions of the microorganisms tested: E. coli showed the highest reduction (1.78 and 2.43 Log respectively with 1.2 and 1.5 mg l(-1) of peracetic acid) and phages the lowest (ranging between 0.52 and 0.60 Log). Only a concentration of 1.5 mg l(-1) of peracetic acid would enable the effluent to be discharged into surface waters in compliance with Italian regulations. The variability of microbial resistance against the peracetic acid disinfection treatment, underlines the importance of assessing disinfection efficiency by using more than one indicator microorganism. The detection of E. coli could be usefully accompanied by tests for more resistant microorganisms such as enterococci or coliphages. In conclusion, peracetic acid can be used for the disinfection of effluents even at low doses, with the advantage of reducing costs and preventing the formation of significant amounts of genotoxic by-products.

A cross-sectional multicenter survey of Italian hotels was conducted to investigate Legionella spp. contamination of hot water. Chemical parameters (hardness, free chlorine concentration, and trace element concentrations), water systems, and building characteristics were evaluated to study risk factors for colonization. The hot water systems of Italian hotels were strongly colonized by Legionella ; 75% of the buildings examined and 60% of the water samples were contaminated, mainly at levels of ≥10 3 CFU liter −1 , and Legionella pneumophila was the most frequently isolated species (87%). L. pneumophila serogroup 1 was isolated from 45.8% of the contaminated sites and from 32.5% of the hotels examined. When a multivariate logistic model was used, only hotel age was associated with contamination, but the risk factors differed depending on the contaminating species and serogroup. Soft water with higher chlorine levels and higher temperatures were associated with L. pneumophila serogroup 1 colonization, whereas the opposite was observed for serogroups 2 to 14. In conclusion, Italian hotels, particularly those located in old buildings, represent a major source of risk for Legionnaires' disease due to the high frequency of Legionella contamination, high germ concentration, and major L. pneumophila serogroup 1 colonization. The possible role of chlorine in favoring the survival of Legionella species is discussed.

Background Since vaccinations are an effective prevention tool for maintaining the health of society, the monitoring of immunization coverage allows us to identify areas where disease outbreaks are likely to occur, and possibly assist us in predicting future outbreaks. The aim of this study is the investigation of the coverage achieved for compulsory (diphtheria, tetanus, polio, hepatitis B,) and recommended (pertussis, Haemophilus influenzae, measles-mumps-rubella) vaccinations between 1998 and 2002 in the municipality of Bologna and the identification of the subjects not complying with compulsory and recommended vaccinations. Methods The statistics regarding vaccinal coverage were elaborated from the data supplied by the Bologna vaccinal registration system (1998–2000) and the IPV4 program (2001–2002). To calculate the coverage for compulsory vaccinations and cases of non-compliance reference was made to the protocol drawn up by the Emilia Romagna Regional Administration. The reasons for non-compliance were divided into various categories Results In Bologna the levels of immunization for the four compulsory vaccinations are satisfactory: over 95% children completed the vaccinal cycle, receiving the booster for anti-polio foreseen in their 3rd year and for anti-dyphteria, tetanus, pertussis at 6 years. The frequency of subjects with total non-compliance (i.e. those who have not begun any compulsory vaccinations by the age of one year) is generally higher in Bologna than in the region, with a slight increase in 2002 (2.52% and 1.06% in the city and the region respectively). The frequency of the anti-measles vaccination is higher than that of mumps and rubella, which means that the single vaccine, as opposed to the combined MMR (measles-mumps-rubella) was still being used in the period in question. The most common reason for non compliance is objection of parents and is probably due to reduction of certain diseases or anxiety about the possible risks. Conclusion In Bologna the frequency of children aged 12 and 24 months who have achieved compulsory vaccination varied, in 2002, between 95% and 98%. As regards recommended vaccinations the percentage of coverage against Haemophilus influenzae is 93.3%, while the levels for measles, mumps and pertussis range from 84% to approx. 92%. Although these percentages are higher if compared to those obtained by other Italian regions, every effort should be made to strengthen the aspects that lead to a successful vaccinal strategy.

This study was performed to identify which disinfection procedures are currently used in dental offices and to evaluate staff knowledge regarding infection control. Information was collected by means of a questionnaire to which 226 subjects responded. Glutaraldehyde was found to be the most commonly used disinfectant for surfaces/drill units, handpieces and instruments; however, half of the respondents did not specify which disinfectants they used. Eighty-four percent of the respondents reported contact times, which in some cases were found to be insufficient; 43,4% stated that containers are washed and disinfected each time the disinfectant is replaced; 58.8% reported that dental handpieces and instruments are precleaned prior to sterilization while 73% believe that increased attention during performance of work practices could reduce the risk of infection. These findings suggest that dental health care personnel need to be better sensitized toward infection control measures and should be offered periodical training on the proper implementation of practice guidelines.

Tests for Escherichia coli and E. coli O157 were carried out on meat samples collected from randomly chosen stores throughout the city of Bologna and suburban areas. The samples consisted of 25 g of loose minced beef, sometimes already shaped into meatballs or hamburgers, some of which were mixed with vegetables. The meat was purchased from retail outlets, open market stalls, and supermarket chains during 25 sampling visits from October 2000 to December 2001. For E. coli detection, Tryptone soya broth (TSB) supplemented with novobiocin and C-EC agar were used. Immunomagnetic separation with SMAC-BCIG-CT agar and chromogenic E. coli O 157 agar, API 20E system and agglutination latex test were used to detect E. coli O157; Vero cell assay and polymerase chain reaction (PCR) were used to assess toxin production and the presence of virulence genes. E. coli were detected in 45 (30.2%) of the 149 samples examined, mainly in the hamburger samples mixed with vegetables and in the loose minced beef. E. coli O157 was found in one sample of hamburger and two samples of hamburger mixed with vegetables (2%) collected from three different butcher's stores between July and October. All the strains of E. coli O157 and most cases of E. coli were found in meat from small retailers. The three strains of E. coli O157 were positive for verocytotoxin production. PCR analysis revealed genes coding for vt2 and one strain possessed the gene for eae A. Chromogenic E. coli O157 agar was found to be more selective and differential, allowing easier identification of suspected colonies with mixed flora and producing less false-positive colonies.

Aims: Transmission of microbial pathogens to patients from water in dental units is a concern. To reduce this risk, the decontaminating efficiency of hydrogen peroxide was evaluated. Methods and Results: Three percent hydrogen peroxide diluted 1 : 4 in distilled water (contact time 15 min) was used daily to disinfect the waterlines of a pilot unit previously contaminated with Pseudomonas aeruginosa or Staphylococcus aureus. The behaviour of the test bacteria was seen to differ over time. Staph. aureus numbers slowly decreased until only low numbers were recovered, after which the levels remained stable. Ps. aeruginosa abatement was more rapid and the density of the bacteria reached a peak when the circuit was empty. Conclusions:Staph. aureus and Ps. aeruginosa treated with hydrogen peroxide fell from 6 to 4 log. Significance and Impact of the Study: Treatment of dental unit waterlines with hydrogen peroxide was seen to be able to keep the number of the bacteria under control, as long as the treatment was repeated daily.

Since some coagulase-negative staphylococci species are involved in clinical and environmental situations, the authors carried out a study on the spread of these bacteria in the air of a sewage treatment plant. For these purposes a total of 196 samples were taken from 16 sampling stations, 11 during the day and 5 at night (only at 4 points), using the settle plate technique. Altogether 13 species of coagulase negative staphylococci were isolated: S. haemolyticus, S. xylosus and S. cohnii were particularly common. Station no. 2 (an area almost always kept closed containing the fine screens) was found to be the most contaminated. The presence of coagulase negative staphylococci was favoured by high temperatures and low humidity. No differences were found due to variations in wind speed and direction or between day and night.

The aim of this study was to investigate the smoking habits of a sample of second year high school students in Romagna (Northern Italy) by means of an anonymous self-administered questionnaire and the efficiency of a previous health education campaign. A sample of 2,691 16-year-old pupils (74% of the school population of this age) was randomly selected. Of these, 863 (32.1%) had participated in a prevention campaign while attending middle school. 19.1% of the students who had taken part in the campaign were smokers compared to 23.2% of those who had not. The students' smoking habits were found to be influenced by the type of school and by the role models (parents, siblings, friends, teachers). The campaign appears to have had good results, especially in places where it was carried out on a wide scale. Suggestions are made for making such campaigns more efficient.

Samples of drinking water were examined in order to evaluate the occurrence of two gram-negative bacteria: Burkholderia pseudomallei and B. cepacia. A total of 85 samples were collected from public and private buildings in the province of Bologna (Italy). Other bacteriological indicators (heterotrophic plate count at 22 and 36 degrees C) were also examined, together with physical and chemical parameters (temperature, pH, residual chlorine, total hardness and chemical oxygen demand (COD)). High levels of B. pseudomallei were recovered (mean value = 578 cfu/100 ml) in about 7% of samples, while B. cepacia was recovered in 3.5% (mean value = < 1) of the samples. The two microorganisms were found to correlate positively with heterotrophic plate counts at 22 and 36 degrees C, but not with the physical and chemical parameters taken into consideration.

A study was carried out to evaluate the extent of the colonization of dental water systems by Comamonas acidovorans and to investigate how the occurrence of these bacteria is related to certain water characteristics. The 152 water samples were collected from the oral rinsing cup, air-water syringe, turbine and supply lines to dental units. Comamonas acidovorans was found most frequently and in greatest quantities in samples taken from water entering the units and in samples with a lower total bacterial count at 22 degrees C, higher temperature, lower content of organic matter and, in general, higher concentrations of residual chlorine.

A study was carried out to evaluate the extent of contamination by Staphylococcus spp. and in particular by Staphylococcus aureus in dairy products on sale in the Bologna area. Staphylococcus aureus was found in 16.30% of the 135 cheese samples examined: 8.3% in soft cheese, 17.60% in blue cheese, 18.9% in semi-soft cheese and 25.0% in mozzarella-type cheese. The mean concentration was 2699 CFU/g in the 22 positive samples. The most commonly found species were Staphylococcus epidermidis (14.8%), Staphylococcus hominis (19.5%), Staphylococcus xylosus 2 (19.2%) and Staphylococcus cohnii (16.3%). Staphylococcus aureus was found mostly during the hot months while the other common species were found mostly in the period October-March.

SUMMARYMicroaerophilic organisms were monitored in sewage effluent undergoing two secondary treatments: air and oxygen-activated sludge. The mean numbers ofArcobacter cryaerophilusand thermophilic campylobacters detected in incoming sewage were 5639/100 ml and 1720/100 ml respectively.Secondary treatment in air tanks reduced the population ofA. cryaerophilusby 97.1% and of thermophilic campylobacters by 99.08%, whereas treatment in oxygen tanks reduced the bacteria 97.8% and 99.63% respectively, showing that oxygen-activated sludge treatment was more effective. Subsequent tertiary treatment with 2 p.p.m. chlorine dioxide evidenced the removal ofA. cryaerophilusto 99.9% and eliminated thermophilic campylobacters.Campylobacter jejuniandC. coliconstituted 54.1% and 45.9% of 74 thermophilic campylobacter strains isolated. In air-activated sludge effluentC. jejuniwas found more often, thus appearing more sensitive to oxygen.The most probable number assay used for detection of campylobacters, blood medium for enrichment and blood-free medium for plating, also appeared to be fit forA. cryaerophilus, the high density of which in urban sewage may be due to inflows from slaughterhouses.

We investigated Legionella and Pseudomonas contamination of hot water in a cross-sectional multicentric survey in Italy. Chemical parameters (hardness, free chlorine, and trace elements) were determined. Legionella spp. were detected in 33 (22.6%) and Pseudomonas spp. in 56 (38.4%) of 146 samples. Some factors associated with Legionella contamination were heater type, tank distance and capacity, water plant age, and mineral content. Pseudomonas presence was influenced by water source, hardness, free chlorine, and temperature. Legionella contamination was associated with a centralized heater, distance from the heater point >10 m, and a water plant >10 years old. Furthermore, zinc levels of 50 microg/L appeared to be protective against Legionella colonization [corrected]. Legionella species and serogroups were differently distributed according to heater type, water temperature, and free chlorine, suggesting that Legionella strains may have a different sensibility and resistance to environmental factors and different ecologic niches.