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ABSTRACT: To compare the standard culture method with a new, rapid test (ScanVIT-Legionella™) using fluorescently labelled gene probes for the detection and enumeration of Legionella spp. The new technique was validated through experiments conducted on both artificially and naturally contaminated water and through an inter-laboratory comparison.
All samples were processed by the ScanVIT test according to the manufacturer's instructions and by a culture method (ISO 11731). ScanVIT detected significantly more positive samples, although concentrations were similar and a strong positive correlation between the two methods was observed (r = 0.888, P < 0.001). The new test was more accurate in identifying the co-presence of Legionella pneumophila and Leg. non-pneumophila. ScanVIT showed a slightly higher Legionella recovery from water samples artificially contaminated with Leg. pneumophila alone or together with Pseudomonas aeruginosa. Lastly, the inter-laboratory comparison revealed that the ScanVIT test exhibits a lower variability than the traditional culture test (mean coefficient of variation 8.7 vs 16.1%).
The results confirmed that the ScanVIT largely overlaps the reference method and offers advantages in terms of sensitivity, quantitative reliability and reduced assay time.
The proposed method may represent a useful validated alternative to traditional culture for the rapid detection and quantification of Legionella spp. in water.
Letters in Applied Microbiology 10/2010; 51(4):421-7. · 1.62 Impact Factor
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ABSTRACT: A prospective observational study was conducted during a two-year period to evaluate the prevalence of hospitalized pneumonia in six hospital units of the Bologna S.Orsola-Malpighi hospital (Italy). The selected units were: general surgery, general medicine, internal medicine, geriatrics, respiratory physiopathology and pneumology, with a total of 205 beds and around 4,800 admissions per year. Data were collected from the clinical cards and cases of pneumonia were distinguished by origin (community-acquired or hospital-acquired according to CDC definition), individual and clinical characteristics, and aetiology. The study involved 486 cases of pneumonia: 75 hospital-acquired and 411 community-acquired (84.6%). Patients affected by hospital-acquired pneumonia were older (average age 77 years) compared to community-acquired cases (74 years) and show a more homogeneous gender distribution (males: 48.0% vs 59.4%). Hospital stays (42 vs 21 days) and mortality rates (24.0% vs 11.7%) were significantly higher in hospital-acquired pneumonia. The incidence rate of nosocomial pneumonia was 7.4 per 1000 hospitalized patients and increased to 17-23 per 1000 in the pneumology and respiratory physiopathology units. Only 16.9% of cases had an aetiological diagnosis (14.1% community-acquired; 31.8% hospital-acquired); the most common isolates were S. aureus and P. aeruginosa. The hospital-acquired cases were caused by Gram-negative bacilli more often than the community-acquired cases, and infections were more frequently polymicrobial (37.5% vs 3.4%). In order to reduce morbidity and mortality due to pneumonia it is important to implement prevention measures in the community (i.e. specific vaccination campaigns), improve clinical protocols for aetiological diagnosis in hospitalised patients and increase epidemiological surveillance of hospital-acquired infections.
Le infezioni in medicina: rivista periodica di eziologia, epidemiologia, diagnostica, clinica e terapia delle patologie infettive 02/2009; 16(4):219-26.
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E Sturchio,
C Minoia,
M Zanellato,
A Masotti, E Leoni,
C Sottani,
G Biamonti,
A Ronchi,
L Casorri,
S Signorini,
M Imbriani
Giornale italiano di medicina del lavoro ed ergonomia 01/2009; 31(1):5-32.
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ABSTRACT: E. LEONI AND P.P. LEGNANI. 2001. Various sample pre-treatment techniques and different growth media for the isolation of Legionellae from hot water supplies in public buildings were compared. A total of 102 hot water samples from taps and showers was examined. The highest recovery frequency was obtained with the heat pre-treatment method and using the selective medium GVPC. However, the results differed according to the concentration of legionellas. In the case of low plate counts (≤5000 cfu l−1), the heat pre-treatment technique gave a significantly higher percentage of positive samples compared with other techniques (P < 0·05). With increasing concentration, the differences between the procedures decreased until they became statistically not significant for concentrations above 50 000 cfu l−1. The direct inoculum method allowed a significantly higher detection of concentrations (P < 0·001) compared with heat and acid decontamination methods, which brought about a 67–68% reduction in detectable Legionellae. Heat decontamination techniques show greater sensitivity and specificity. However, they underestimate the number of legionellas. In environmental surveillance programmes, this underestimate must be taken into consideration when assessing the health risk.
Journal of Applied Microbiology 07/2008; 90(1):27 - 33. · 2.34 Impact Factor
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ABSTRACT: To evaluate the effectiveness of different disinfection treatments in a spa water system contaminated by Legionella pneumophila and associated with a case of Legionella pneumonia.
During an 18-month period, the spa water was analyzed by taking samples from the well, the recirculation line, and the final distribution devices (nebulizers and nasal irrigators). Various attempts were made to eradicate Legionella organisms by chemical and thermal shock. The final protocol consisted of heat shock treatment at 70 degrees C-75 degrees C for 3 hours, 2 nights per week, followed by a lowering of the water temperature to 30 deg C+/-1 deg C for use in the plant. In addition, 3 times a week superheated steam (at a pressure of 1 atmosphere) was introduced for 1 hour into the nebulization machines.
A spa at which sulfurous water was used for hydrotherapy by means of aerosol and nasal irrigation.
A 74-year-old woman with legionnaires disease.
After the case of infection occurred, L. pneumophila was isolated from the recirculation line at a concentration of 400,000 cfu/L and from the nebulizers and nasal irrigators at levels ranging from 3,300 to 1,800,000 cfu/L. The colonizing organisms consisted of a mixture of L. pneumophila serogroup 1 (12%) and serogroup 5 (88%). The shock treatment with chlorine dioxide and peracetic acid resulted in the eradication of Legionella organisms from the recirculation line but not from the water generated from the final distribution devices. After the restructuring of the plant and the application of thermal shock protocol, an evaluation after 12 months revealed no evidence of Legionella contamination.
To prevent Legionella colonization, disinfection treatment is effective if associated with carefully selected materials, good circuit design, and good maintenance practices.
Infection Control and Hospital Epidemiology 08/2006; 27(7):716-21. · 3.67 Impact Factor
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ABSTRACT: 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).
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 40.0% of the distribution systems, L. pneumophila in 33.3%. The highest colonization was found in the hot water systems of hospitals (93.7% of samples positive for L. pneumophila, geometric mean: 2.4 x 10(3) CFU l(-1)), followed by the hotels (60.9%, geometric mean: 127.3 CFU l(-1)) and the apartments with centralized heating (41.9%, geometric mean: 30.5 CFU l(-1)). The apartments with independent heating systems showed a lower level of colonization (3.6% 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. No 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.
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.
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.
Journal of Applied Microbiology 02/2005; 98(2):373-9. · 2.34 Impact Factor
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ABSTRACT: The hot water supplies of 11 private healthcare facilities in the city of Bologna, Italy, were monitored for the presence of Legionella spp. Four samplings were made in each establishment over a period of one year and in total 121 samples were collected from distribution points situated near the water-boiler and inside the wards (taps and showers). Legionellae were recovered from all the water supplies in question: Legionella spp. in 86.8% of samples, L. pneumophila in 82.6% of samples. L. pneumophila was found in all the water supplies at levels averaging above 10(4)cfu/L in five health facilities and reaching a maximum concentration of 10(7)cfu/L. The only parameter to have affected the presence of legionellae was the water temperature, which was seen to be inversely correlated to the concentration of Legionella spp. Despite the high levels of contamination from L. pneumophila, no cases of nosocomial Legionnaires' disease were reported during the period of the study.
Journal of Hospital Infection 04/2002; 50(3):220-3. · 3.39 Impact Factor
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ABSTRACT: A study was carried out to evaluate the prevalence of bacteria of the Legionella genus in the water from the pools and showers of 12 swimming pools in the city of Bologna (Italy). Sampling took place four times for every establishment, once for each season of the year. Legionella spp. were found in 2 of the 48 pool water samples (L. micdadei and L. bozenanii) and in 27 of the 48 samples taken from the hot water of the showers: 19 were positive for L. pneumophila (10-19,250 cfu/l) and 18 for other species (20-6000 cfu/l). The contamination was seen to be consistent throughout the year, since the same species of legionellae were isolated at different samplings and in concentrations that did not reveal any seasonal trend. The legionellae and the Gram negative bacteria were not found in shower water with a temperature above 43 degrees C. However, in the samples of shower water with a lower temperature a statistically significant inverse correlation was seen between legionellae and Pseudomonas aeruginosa (r = -0.51; p<0.01) as well as between legionellae and Gram negative bacteria (r = -0.70; p<0.01). The potential risk of contracting infections from Legionella spp. in the swimming pool environment does not seem to be linked to the pool water, but to that of the showers. The water temperature of showers should therefore be maintained at a level high enough to prevent the reproduction of these bacteria.
Water Research 10/2001; 35(15):3749-53. · 4.86 Impact Factor
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ABSTRACT: Various sample pre-treatment techniques and different growth media for the isolation of Legionellae from hot water supplies in public buildings were compared. A total of 102 hot water samples from taps and showers was examined. The highest recovery frequency was obtained with the heat pre-treatment method and using the selective medium GVPC. However, the results differed according to the concentration of legionellas. In the case of low plate counts (< or =5000 cfu l(-1)), the heat pre-treatment technique gave a significantly higher percentage of positive samples compared with other techniques (P < 0.05). With increasing concentration, the differences between the procedures decreased until they became statistically not significant for concentrations above 50 000 cfu l(-1). The direct inoculum method allowed a significantly higher detection of concentrations (P < 0.001) compared with heat and acid decontamination methods, which brought about a 67-68% reduction in detectable Legionellae. Heat decontamination techniques show greater sensitivity and specificity. However, they underestimate the number of legionellas. In environmental surveillance programmes, this underestimate must be taken into consideration when assessing the health risk.
Journal of Applied Microbiology 01/2001; 90(1):27-33. · 2.34 Impact Factor
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ABSTRACT: In August 1997, an outbreak of gastroenteritis from Salmonella Hadar phage type 2 occurred among customers of a restaurant in Rimini (Emilia-Romagna region, Italy). Twenty-nine people who had eaten food prepared in the restaurant on 2 or 3 August had symptoms of acute gastroenteritis. The infection was culture-confirmed in 24 cases and the stool specimens of four healthy people were positive for Salmonella Hadar. Twelve people had to be hospitalized and a 3-year old girl died. The case-control study identified roast rabbit as the likely vehicle of infection (OR: 6.00; CI 95%: 1.65-22.83). The microbiological investigation carried out on food taken from the restaurant confirmed high levels of Salmonella Hadar in a sample of roast rabbit. Since the rabbit was well cooked, the food contamination likely occurred after cooking. Poor hygienic conditions found in the restaurant, together with inappropriate food-handling practices and inadequate storage temperatures may have contributed to spread to other foods and the severity of the outbreak.
European Journal of Epidemiology 02/2000; 16(7):613-8. · 4.71 Impact Factor
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ABSTRACT: A 5-year study was carried out on the growth curve of two strains of P. aeruginosa inoculated at a density of 10(2) cfu/ml into samples of natural mineral water with different levels of dissolved solids (TDS at 180 degrees C: 72.5 and 382 mg/l) and low organic content (TOC: 0.17 and 0.35 mg/l). The resulting growth curves were similar for both strains, with only slight differences depending on the different amounts of dissolved solids in the water. After 4-5 days counts were increased by 3 log units. This level was maintained until 70-100 days from inoculation, after which a slow decrease began, culminating in the death of one of the strains after 5 years. No difference in recovery was observed between the method using direct inoculation on Cetrimide Agar and the resuscitation technique (preincubation in Tryptone Soya Agar followed by inoculation on Cetrimide Agar) in the exponential phase of the growth curve. During the stationary and death phases, however, the enrichment technique gave statistically slightly higher counts than the selective technique, indicating the presence of damaged P. aeruginosa cells. The use of a resuscitation step when using Cetrimide Agar to assess bottled water quality is recommended.
International Journal of Food Microbiology 01/2000; 53(2-3):153-8. · 3.33 Impact Factor
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ABSTRACT: A study was performed to evaluate the prevalence of non-tubercular mycobacteria in swimming pool environments. The bacteria in question were found in 88.2% of pool water samples. The most frequent species were Mycobacterium gordonae (73.5% of samples; range 1-840 cfu 100 ml - 1), M. chelonei (38.2% 2-360 cfu 100 ml - 1) and M. fortuitum (35.3% 2-250 cfu 100 ml - 1). The same species were also recovered from the water at the different phases of the treatment cycle, with relative percentages similar to those of the pool water. Shower floors and pool edges also presented high concentrations of the mycobacteria (100% of samples) and M. marinum was isolated from the surfaces of pool edges on two occasions (4.5% of samples). The swimming pool environment provides a suitable habitat for the survival and reproduction of mycobacteria. Although mycobacteria are common in swimming pools, human mycobacterial disease associated with their use is rare. Apart from superficial infections with M. marinum, the risk of more serious diseases in subjects with weakened immune systems should not be underestimated, given the widespread presence of mycobacteria that are possible opportunistic pathogens and the direct contact bathers have with the water and aerosol.
Journal of Applied Microbiology 12/1999; 87(5):683-8. · 2.34 Impact Factor
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ABSTRACT: Twelve public swimming pools in Bologna (Emilia-Romagna region, Italy) were investigated for the microbiological quality of water and surfaces of the pool edges, showers and changing rooms. At the same time a cross-sectional study was carried out on the health of 238 users (bathers) compared with 238 controls who practised sports other than swimming. Data regarding duration and frequency of exposure, behaviour and recent medical history were gathered by means of a questionnaire. All participants also underwent a medical examination. Compliance of the pool water to the microbiological standards set by Italian regulations was generally good; compliance was total when free chlorine residual was within the recommended limits. However, when analysis was extended to the various surfaces, potentially pathogenic bacteria such as P. aeruginosa and C. albicans were isolated. Eye burning and diarrhoea were the only declared symptoms and verrucas the only diagnosed disease showing statistically significant differences between bathers and controls. Verrucas tended to increase in proportion to exposure. Athlete's foot had a very high prevalence among both bathers (34 %) and controls (27.3%) and controls (27%). The environmental and epidemiological investigations both confirmed the risk of infection, mainly associated with the contamination of surfaces.
Public Health 10/1999; 113(5):227-32. · 1.35 Impact Factor
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ABSTRACT: Shellfish (mussels and clams) and shellfish-growing waters were examined for indicator bacteria according to the EC regulations, Salmonella spp., coliphages and anti-Salmonella phages. Samples were collected both from natural-growing areas along the coast and from authorized shellfish-harvesting beds. The coastal area was affected by organic pollution and extensive faecal contamination and, according to the legal requirements, was unsuitable for shellfish farming. The shellfish collected along the coast also showed faecal contamination at levels which did not conform to legal standards. No significant differences were observed between the frequency of isolation of somatic coliphages and indicator bacteria from sea water. In contrast, both the authorized and wild coastal shellfish were contaminated by coliphages at a significantly higher level than the corresponding bacterial indicators for faecal contamination (chi 2 test, P < 0.01). Coliphage concentrations were significantly correlated with faecal indicators in marine waters (P < 0.001) and sediments (P < 0.05), but no correlation was found in shellfish, thus showing their low specificity as indicators of faecal pollution of human origin in shellfish of economic importance.
Journal of Applied Microbiology 12/1998; 85(5):790-8. · 2.34 Impact Factor
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ABSTRACT: A study was made of the occurrence of Aeromonas spp. in drinking water supplies in a mountain area in northeast Italy (the Dolomites). On account of its location, the water in question is exposed to a low level of pollution and systematic chemical disinfection is not necessary. Out of 7395 water samples analysed over a 3 year period, 1623 (21 x 95%) were found to be positive for Aeromonas, with levels ranging from 1 to 240 cfu 100 ml-1; 72 x 4% of the strains were identified as Aer. hydrophila, 14 x 7% as Aer. caviae and 12 x 9% as Aer. sobria. The percentage of recovery from surface water (approximately 40%) was found to be higher than that of ground water (springs: 24 x 9%; wells : 28x 6%). Aeromonas spp. were isolated from 21 x 7% of samples from the distribution network and showed no significant variations compared with water from reservoirs. There was no evidence, therefore, of after-growth in the distribution system. No correlation was found between the concentration of Aeromonas spp. and faecal indicator organisms. As the distribution of Aeromonas spp. was unrelated to anthropic pollution, it is believed that the search for these micro-organisms should be adopted as a further indicator of drinking water quality, especially in waters such as those in the present investigation not undergoing systematic purification treatment.
Journal of Applied Microbiology 09/1998; 85(2):271-6. · 2.34 Impact Factor
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ABSTRACT: An outbreak of hepatitis A is described involving thirteen cases in a town in central-northern Italy. The consumption of infected clams, caught in a polluted coastal area of the Adriatic Sea, caused hepatitis A in all five members of a family consisting of mother, father and children, two of whom attended primary school. The epidemic subsequently spread to the primary school with a secondary attack rate of 7.9%, 0 for female pupils and 18.9% for males. The epidemiological and environmental investigations showed that the critical exposure took place in the boys' toilet in the primary school (OR: 32.79, 95% CI: 6.83-157.45). To prevent the spreading of contagion, extra disinfection was carried out in the whole school and health education campaigns were mounted. The good basic hygienic conditions of the homes, together with the cooperation of school staff in surveillance and providing information, allowed the epidemic to be controlled.
European Journal of Epidemiology 03/1998; 14(2):187-92. · 4.71 Impact Factor
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ABSTRACT: Wash water from self-service washing machines in three commercial launderettes of Bologna (Italy) were examined to verify which factors affect their bacterial contamination and to determine which procedures in the laundering process have the most significant effects on the removal of bacteria. Four washing formulas were compared: a delicates cycle (programmed temperature 25-30 degrees C; actual temperature: 28-31 degrees C); a whites cycle (programmed temperature: 80-90 degrees C; actual temperature: 50-57.5 degrees C); a delicates cycle with the addition of an oxygen-based bleach safe for delicate fabrics and a whites cycle with the addition of an oxygen-based bleach. Bacterial contamination of washing machines was higher in the launderette most heavely used, and, furthermore, it was in relation with the washing temperature and the use of bleaches. The low temperature laundering cycle (20-30 degrees C) did not guarantee elimination of bacterial content from either the inside of the washing machine or from the fabric being washed. Washing with water at a higher temperature, of about 55 degrees C, or adding an oxygen-based bleach to the low temperature cycle did ensure a significant reduction in bacterial recovery from water samples and fabrics, but did not prevent bacteria such as P. aeruginosa from surviving inside the washing machine. Only the addition of bleaches to the hot water program ensured the almost total elimination of bacteria and also guaranteed their elimination from protected parts of the drum.
Zentralblatt für Hygiene und Umweltmedizin = International journal of hygiene and environmental medicine 11/1997; 200(4):319-33.
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ABSTRACT: The efficiency of a number of tertiary treatment systems--filtration, ozonation, chlorination with low levels (TRC < 0.2 ppm) and high levels (TRC < 1 ppm) of residual chlorine--in the disinfection of secondary effluent was assessed in a purification plant treating mixed sewage of municipal (83%) and industrial mainly textile origin (17%). Maximum purification effect was observed when, following secondary treatment with biological oxidation, the sewage was submitted to combined filtration--ozonation treatment (reduction in bacterial indicators of from 4.9 to 7.2 log10 units) or with chlorination with high levels of residual chlorine (reduction in the bacterial indicators of between 2.8 and 4.6 log10 units). However, only ozonation reduced viral indicators with respect to inflow sewage by more than 3 log10 units, the limit considered acceptable for a biological treatment system with supplementary tertiary disinfection treatment. Ozonation however did not complete control all the biological forms present in the sewage, in particular the viruses, present in 36% of ozonized samples at concentrations of from 1 to 480 PFU/100 mL. Ozonation and high-concentration chlorination do not seem to be unfavorably influenced by wastes from laundry and deyng processing; achieving a complete decolorization of the treated effluent, they prove to the suitable treatments for mixed sewage of municipal and industrial mainly textile origin.
Zentralblatt für Hygiene und Umweltmedizin = International journal of hygiene and environmental medicine 07/1996; 198(6):552-66.
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ABSTRACT: Indoor climate indices and microbiological airborne contamination were evaluated in a department of a general hospital in Bologna only partially equipped with an air conditioning system. To determine the environmental parameters, an ANADATA (LSI) climate analyzer with relative transducers was used. The Effective Temperature (ET), the New Effective Temperature (ET*) and the Fanger indices (PMV-PPD) were calculated using the parameters measured. Microbial count measurements were taken with an S.A.S. (Surface Air System) sampler, to ascertain the total bacterial count at 37 degrees C, and the fungal particle, Staphylococcus aureus and Pseudomonas aeruginosa counts. Carbon dioxide air concentrations were also measured to evaluate the efficacy of air exchange. The Fanger indices were not within the range of thermal comfort in most rooms (52% in winter, 62% in summer). Air microbial counts were higher in the hospital wards and surgeries than in the offices and laboratories. In particular, coagulase-positive staphylococci were present only in the air of the patients' rooms. The microbial contamination was not correlated with the air conditioning system, but probably caused by the turnover in the hospital population, the number of people and their behaviour. However the most important measure to prevent airborne contamination and to reduce the number of microorganisms in the air is an efficient source control. Better management of the air conditioning system, by means of adequate air exchange and thermal adjustment, would lead to a notable improvement in indoor air quality, especially in units with hospitalized patients.
Zentralblatt für Hygiene und Umweltmedizin = International journal of hygiene and environmental medicine 08/1993; 194(4):405-18.
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ABSTRACT: In response to a request from the personnel of a credit bank that had been moved into a new building, an evaluation was made of employee health complaints. The prevalence of symptoms was determined using a self-administered questionnaire. Ventilation effectiveness, contaminant concentrations (which included chemicals and bioaerosols) and microclimate were studied to establish their relationship to environmental discomfort and to the health problems mentioned by the employees. Indoor air quality--which was assessed in different seasons--revealed relatively high levels of carbon dioxide and bioaerosols in areas occupied by employees as compared with other places. Temperature and humidity were considered to be satisfactory. Although a causative agent was not isolated, the authors conclude that an ineffective rate of room air exchange, possibly in interaction with chemical contaminants, may be responsible for the discomfort and, perhaps, for the health symptoms experienced by workers in fully enclosed rooms.
Archiv für Gewerbepathologie und Gewerbehygiene 02/1991; 63(4):233-9. · 1.89 Impact Factor
