Detection of viable but non-culturable legionella in hospital water network following monochloramine disinfection

BACKGROUND

Prevention of legionellosis remains a critical issue in healthcare settings where monochloramine (MC) disinfection was recently introduced as an alternative to chlorine dioxide in controlling Legionella spp. contamination of the hospital water network. Continuous treatments with low MC doses in some instances have induced a viable but non-culturable state (VBNC) of Legionella spp.

AIM

To investigate the occurrence of such dormant cells during a long period of continuous MC treatment.

METHODS

Between November 2010 and April 2015, 162 water and biofilm samples were collected and Legionella spp. isolated in accordance with standard procedures. In sampling sites where MC was <1.5mg/L, VBNC cells were investigated by ethidium monoazide bromide (EMA)-real-time polymerase chain reaction (qPCR) and 'resuscitation' test into Acanthamoeba polyphaga CCAP 1501/18. According to the Health Protection Agency protocol, free-living protozoa were researched in 60 five-litre water samples.

FINDINGS

In all, 136 out of 156 (87.2%) of the samples taken from sites previously positive for L. pneumophila ST269 were negative by culture, but only 47 (34.5%) negative by qPCR. Although no positive results were obtained by EMA-qPCR, four out of 22 samples associated with MC concentration of 1.3 ± 0.5mg/L showed VBNC legionella resuscitation. The presence of the amoeba A. polyphaga in the hospital water network was demonstrated.

CONCLUSION

Our study is the first report evidencing the emergence of VNBC legionella during a long period of continuous MC treatment of a hospital water network, highlighting the importance of keeping an appropriate and uninterrupted MC dosage to ensure the control of legionella colonization in hospital water supplies.

Silver zeolite antimicrobial activity in aluminium heating, ventilation and air conditioning system ducts

INTRODUCTION

Air pollution in confined environments is a serious health problem, in that most people spend long periods indoors (in homes, offices, classrooms etc.). Some people (children, the elderly, heart disease patients, asthmatic or allergic subjects) are at greater risk because of their conditions of frailty. The growing use of air-conditioning systems in many public and private buildings aggravates this health risk, especially when these systems are not correctly installed or regularly serviced. The aim of our study was to verify the capacity of Ag+ ions to stop the growth of bacteria and moulds inside the ducts of Heating, Ventilation and Air Conditioning system ducts (HVAC) systems when these ducts were lined with active Ag+ ions zeolite-coated panels.

MATERIAL AND METHODS

A Y-shaped HVAC model with two branches was used; one branch was made of traditional galvanized iron, as was the whole system, while the other was lined with active Ag+ zeolite-coated polyurethane panels. During the test, samples of dust present inside both ducts were collected and seeded in liquid and solid media to detect bacteria and moulds. The presence of bacteria was also sought in the air emerging from the outlets of both ducts.

RESULTS

Tests made on samples of particulate collected from the two different ducts revealed a lower total bacterial load in the samples collected from the Ag+ zeolite-coated duct than in the samples from the traditional Zn galvanized duct. In addition, the values of bacterial load found in the air emerging from the Ag+ ions zeolite-lined duct were 5 times lower than those found in the air from the traditional galvanized iron duct.

CONCLUSIONS

The utilization of Ag+ zeolite-coated panels in air-conditioning systems could improve the quality of the emerging air in comparison with traditional installations in galvanized iron. This innovation could prove particularly advantageous in the event of accidents during the installation of air-conditioning systems or of contaminated aerosols coming from outside.

Genetic diversity of bacterial strains isolated from soils, contaminated with polycyclic aromatic hydrocarbons, by 16S rRNA gene sequencing and amplified fragment length polymorphism fingerprinting

In order to study microbial diversity in a polycyclic aromatic hydrocarbon-impacted soil, 14 bacterial strains were analyzed by 16S rRNA gene sequencing and amplified fragment length polymorphism (AFLP) analysis. Bacterial strains isolated from two different hydrocarbon-polluted sites were identified to the species level by 16S rRNA full-gene sequencing using MicroSeq 16S rRNA gene sequencing. Their genome was subsequently analyzed by high-resolution genotyping with AFLP analysis, in order to monitor species variability and to differentiate closely related strains. Cluster analysis based on AFLP fingerprinting showed intra-specific polymorphism, even among strains with 100% 16S rRNA gene sequence identity. The results show that AFLP is a powerful, highly reproducible and discriminatory tool for revealing genetic relationships in bacterial populations. The ability to differentiate and track related closely microbes is fundamental for studying structure and dynamics of microbial communities in contaminated ecosystems.

[Preventive measures suggested to protect health workers from the risk due to a potential exposure to SARS agents]

The Authors describe the personal and environmental preventive measures suggested to protect health workers from the risks due to a potential exposure to SARS agents. The Authors stress the need that workers are allowed to wear individual protective disposable complying with technical regulations in order to be assured the best protection.

Bronchial hyperresponsiveness in children and adolescents with Crohn's disease

Pulmonary manifestations have been described in Crohn's disease (CD). Bronchial responsiveness to methacholine (MCh) was evaluated in 14 children with CD with no evidence of airway disease, 10 asthmatics, and 10 healthy subjects. In patients with CD total blood eosinophils and serum IgE were 0.20 x 10(9) x L(-1) (95% CI -1.68 to 2.08) and 138.4 kU x L(-)(1) (95% CI 18.84 to 257.96), respectively. Three patients with CD had positive prick tests. Bronchial hyperresponsiveness (BHR) was demonstrated in 10 patients with CD (71%) and in the asthmatics, but not in control subjects. In patients with CD PD(20) appeared significantly greater than in asthmatics (699 microg [95% CI 238 to 1,115] versus 104 microg [95% CI 37.35 to 293]; p < 0.05), and was not related either to baseline FEV(1) or IgE or eosinophils (r = 0.32; r = -0.5; r = -0.15, p = NS, respectively). Neither activity nor treatment or duration of CD affected BHR. Five nonatopic CD patients underwent a second MCh challenge over a 25-mo period: the PD(20) appeared significantly greater than basal PD(20) (1,941 microg versus 575 microg, p < 0.05, respectively), in the absence of significant changes of disease activity. BHR might be the expression of subclinical airway inflammation, a phenomenon which can be responsible for the development of various pulmonary manifestations in CD.

In vitro effect of natural and semi-synthetic carbohydrate polymers on Chlamydia trachomatis infection

The effect of different natural and semi-synthetic polysaccharides on Chlamydia trachomatis multiplication in Hela 229 cells was evaluated. Some neutral, negatively and positively charged carbohydrates were able, in a dose-dependent fashion, to inhibit chlamydial infection by interfering mainly with the adsorption process. The inhibiting compounds, whose effect was shown within the concentration range of 8-200 micrograms/ml, were in order of action: dextran sulphate > glyloid sulphate 4327 > glycogen sulphate 4427 > arabic gum = glyloid > chitosan > glycogen. Data obtained suggested that antichlamydial activity was not only related to the electric charge of these molecules but could also be attributed to other features of their polymeric backbone. Since carbohydrate polymers have also been shown to inhibit the early stages of infection by viral agents causing sexually transmitted diseases, the employment of these molecules for prevention or treatment of mixed viral-C. trachomatis infections can be hypothesized.

In vitro study of a double infection by herpes simplex virus type 2 and Chlamydia trachomatis

Sexually transmitted diseases (STDs) may recognize multiple etiological agents. Among them, Chlamydia trachomatis (Ct) and herpes simplex virus type 2 (HSV-2) cause symptomatic, subclinical and asymptomatic infections of the urogenital tract which can lead to serious sequelae. In the present study the coinfection and superinfection by Ct and HSV-2 in epithelial cultured cells from human cervix (HeLa 229) are described. A double infection, followed by the intracellular synthesis of chlamydial and viral antigens, was established. Both synergistic and interfering phenomena were recorded: viral antigen synthesis resulted increased whereas Ct inclusion bodies were produced to a lower extent.

[Clinico-diagnostic considerations on various cases of lymphogranuloma venereum]

The authors report some recently observed cases of lymphogranuloma venereum and focus their attention on the complex approach to clinical and laboratory diagnosis. Furthermore they underline the importance and the spread of this disease in new geographical area, such as Europe.

Metabolic alkalosis due to the use of an oligoantigenic diet in infancy

A 7-month-old boy on an oligoantigenic diet because of multiple food intolerances presented with anorexia, failure to gain weight and severe hypochloremic metabolic alkalosis with hyperreninemia. Clinical symptoms and biochemical abnormalities disappeared after adequate dietary supplementation with potassium and sodium chloride. This case emphasizes that minimal daily mineral requirements must be provided in infant diets, and highlights the risk of nutritional deficiencies inherent in the prolonged use of oligoantigenic diets not adequately supplemented.

Chlamydia trachomatis genitourinary infections: laboratory diagnosis and therapeutic aspects. Evaluation of in vitro and in vivo effectiveness of azithromycin

Chlamydia trachomatis (C.t.) cell culture represents a sensitive method for the diagnosis of chlamydial infection and the only one which makes it possible to determine the susceptibility of an isolate to antibiotics so that an appropriate drug can be selected for individual treatment. In 11 patients, affected by urethroprostatitis and suspected of treatment failure with standard drug regimens, either due to lack of compliance with therapy or antibiotic resistance, C.t. was isolated in McCoy cell culture from urethral swabs, after prostatic massage. The in vitro activity of azithromycin against these isolates and the in vivo efficacy of the drug in the patients treated with a single 1 g dose have been evaluated. All the C.t. strains tested were susceptible to the action of azithromycin (MIC range 0.125-1.0 microgram/ml). Bactericidal values were one dilution higher (MBC range 0.25-2.0 microgram/ml). These in vitro results are consistent with clinical observations as all the patients treated had negative culture at a 4-week follow-up visit.

Lack of association between clinical and environmental isolates of Pseudomonas aeruginosa in hospital wards

Seventy-three environmental and clinical isolates of Pseudomonas aeruginosa recovered from a single hospital over a 6-month period were compared for epidemiological type characteristics. Environmental isolates were obtained from sinks, taps and water, in rooms where patients were treated. The strains represented only six O-antigenic types and 8.2% of them were not typable. Serotype 011 was most frequent in the environment, whereas serotypes 06, 012 and 02,5 predominated among clinical isolates. More than 60% of all isolates belonged to four pyocin types (1, 10, 33 and 45), and approximately 80% were phage typable. Environmental isolates were more sensitive to antibiotics than clinical isolates. There was little correspondence between the types of strains of P. aeruginosa isolated from patients and those isolated from the environment. However, isolates of identical type were frequently recovered from different patients within the same clinic and were found to be related in time and location. We conclude that the environment was not an important source of P. aeruginosa infection and that transfer of organisms was mainly from patient-to-patient.

Changes in protein C, factor VII and endothelial markers after autologous bone marrow transplantation: possible implications in the pathogenesis of veno-occlusive disease

In a recent prospective study of allogenic bone marrow transplantation we reported that decreases in factor VII and protein C were predictive markers for high risk of veno-occlusive disease (VOD). In order to determine the relative involvement of endothelial and hepatocyte injury in the genesis of VOD, 34 consecutive patients undergoing autologous bone marrow transplantation (BMT) were studied. Conditioning was performed by chemotherapy alone or associated with total body irradiation (TBI). Protein C and factor VII, the endothelial markers Von Willebrand factor (vWF and t-PA, fibrinogen and fibronectin were measured weekly before and after BMT. Protein C and factor VII were within the normal range before BMT, decreased significantly on day 7 to 73 and 64% respectively (p < .01) and then returned to normal values. Fibrinogen increased to 7 g/l (p < .001) on day 7 but then returned to normal levels. Fibronectin was abnormally high (p < .001) before BMT and decreased thereafter, while vWF increased (p < 0.001) for three consecutive weeks. t-PA was low (p < 0.001) before conditioning but increased thereafter. These results demonstrate the presence of endothelial lesions before BMT and acute hepatic and endothelial lesions after conditioning. Although VOD was never observed in our patients, this complication could well arise from preexisting vascular lesions due to previous chemotherapy and/or from acute hepatocytic injury, which could also be of endothelial origin, after conditioning.

[Infection of the vascular prosthesis. The diagnostic, preventive and treatment protocols: preliminary results]

A number of strategies for the management of vascular graft infections are described in literature. Nevertheless, this serious compliance is still burdened with high rates of morbidity and mortality. At the present the principal efforts are therefore directed towards prevention and early diagnosis. In this view, the authors propose their protocol of study, on the basis of the encouraging results till now obtained.

Calcium and phosphorus metabolism in full-term infants

Appropriate intake of dietary calcium and phosphorus is essential for the maintenance of mineral homeostasis and support of adequate bone mineralization in growing infants. Disturbances of calcium homeostasis such as newborn hypocalcemia, have been shown to be secondary to high oral phosphate intake. The incidence of hypocalcemic tetany has changed from epidemic proportions in newborns, who were formerly fed evaporated cow's milk formula, to the present sporadic occurrence in newborns who are now fed humanized cow's milk formula, with a calcium concentration of about 50 mg/dl and a phosphorus concentration of about 35 mg/dl. Human milk, provided vitamin D intake is adequate, has been shown to maintain calcium-phosphorus homeostasis and support adequate bone mineralization at least in the first 6 months of life. After this, the phosphorus content of breast milk could limit mineral accretion in exclusively breast fed infants. The present concentration of calcium and phosphorus in the humanized cow's milk formulas support adequate mineral homeostasis and bone mineralization throughout the first year of life. As bone calcium content is proportional to calcium intake, feeding whole cow's milk from early infancy onward is associated with abnormal bone mineralization. The adequacy of bone mineralization in infants fed soy formula is still controversial.

Virulence determinants in Pseudomonas aeruginosa strains from urinary tract infections

A total of 121 uropathogenic Pseudomonas aeruginosa strains were examined for production of several virulence-related factors. These strains were distributed in five predominant O-serotypes, i.e. O 4, O 12, O 11, O 6 and O 5, which accounted respectively for 23.9, 23.1, 12.3, 8.2 and 5.7% of isolates. Pyochelin and pyoverdin siderophores were produced by most of the isolates, defective variants occurring at very low frequency (2.4% for pyochelin and 7.4% for pyoverdin). Adherence to uroepithelial cells and production of cytotoxins was demonstrated in 52.8 and 67.7% of the strains, respectively, with higher frequencies for epidemiologically related strains belonging to serotypes O 4 and O 12. Titration of total proteases, elastase and phospholipase C revealed a high degree of heterogeneity among isolates. However, examination of individual O-serotypes by exoenzyme production showed that elevated levels of total proteases and elastase were characteristics of serotypes of minor numerical importance, i.e. O 1, O 10, O 11 and O 17, whilst low levels of elastase were produced by strains belonging to the predominant serotypes, namely O 4 and O 12. Moreover, epidemiologically related strains belonging to serotypes O 4 and O 12 appeared more homogeneous than the whole serogroup, when compared with other groups on the basis of exoenzyme levels.

Epidemiological typing of uropathogenic Pseudomonas aeruginosa strains from hospitalized patients

One hundred and twenty-one clinical isolates of Pseudomonas aeruginosa from patients with hospital-acquired urinary tract infections (UTIs) were studied to determine their major epidemiological markers, including API 20NE profile, O-serotype, pyocin type, phage type, lysogenic state and antibiotic susceptibility. Serotypes O4, O12, O11, O6 and O5 were found with a high frequency, accounting respectively for 23.9%, 23.1%, 12.3%, 8.2% and 5.7% of isolates. Pyocin type 10 was most common (32.2%) followed by types 1 (10.7%), 33 (7.5%) and 105 (4.1%); subtype h was predominant being characteristic of 34.7% of isolates. Most of the strains (69.4%) were either not phage typable or sensitive to phages 68 and 119x. Resistance to gentamicin, tobramycin, amikacin, imipenem and ciprofloxacin was more frequent among strains belonging to serotype O12. The O-serotypes were combined with API 20NE profiles, pyocin and phage types, lysogenic states and antibiotic resistance in order to identify epidemiologically related clones. Within predominant serotypes--O4 and O12--most strains displayed similar but not identical type characteristics, whereas other serotypes were less homogeneous. Our results support the concept that a combination of current typing techniques allows the identification of epidemiologically related P. aeruginosa isolates.

Role of membrane glycosphingolipids as Pseudomonas aeruginosa adhesin receptor in rabbit bladder mucosa

The adhesiveness of a mucous strain of Pseudomonas aeruginosa to rabbit bladder mucosa was studied after preincubation of the microorganism with several glycolipids with different carbohydrate moieties to investigate their importance in the interaction with bacterial adhesins. Vesical cells were also treated with lectins (limulin and soybean) to confirm the role of saccharides as membrane receptor. The results obtained showed that galactose-containing glycolipids were able, in varying degrees, to reduce bacterial binding. The most active compounds were glycosphingolipids with negatively charged terminal groups. Lectin treatment of bladder mucosal cells confirmed the importance of galactose and sialic acid as mucosal cell membrane receptors for P. aeruginosa.

Utilization of 12-step theme groups in a short-term chemical dependence treatment unit

At Eagleville Hospital, staff have found that utilizing the theme-group process facilitates patient acceptance of 12-Step programs within a relatively short (three weeks) treatment program. Providing a comprehensive orientation to the 12-Step programs increases the likelihood of patients continuing with 12-Step programs as part of their aftercare programs. As previously noted, this is crucial for continued success and sobriety. It is hoped that this description of the use of 12-Step theme groups as part of a comprehensive treatment program will be of help to others.