International journal of hygiene and environmental medicine 

About: International journal of hygiene and environmental medicine is an academic journal. The journal publishes majorly in the area(s): Population & Fecal coliform. Over the lifetime, 449 publications have been published receiving 3873 citations.

[Acanthamoeba, naturally intracellularly infected with Pseudomonas aeruginosa, after their isolation from a microbiologically contaminated drinking water system in a hospital].

Abstract: The drinking water system of a new hospital building that was highly contaminated with bacteria before opening was investigated too for the prevalence of small free living amoebae. Germ counts resulted in > 100 CFU/ml in 100% of the cold water samples, that showed also growth of P. aeruginosa, whereas E. coli and coliforme bacteria could not be identified. The investigation of 37 water samples for protozoa revealed growth of small freeliving amoebae in 20 samples (54%) belonging to 10 species of the genus Acanthamoeba, Naegleria, Hartmannella, Echinamoeba among others. In addition 2 Ciliate- and 2 Microflagellate-species could be observed. While all Naegleria strains isolated belonged to the N. gruberi-complex two of 16 Acanthamoeba-isolates proved to be pathogenic for laboratory mice. From 7 watersamples positive with P. aeruginosa 5 Acanthamoeba- and 2 Echinamoeba strains could be isolated which revealed intracellular multiplication of P. aeruginosa. Because of their well known resistances against chlorine, the amoebae and their cysts are considered to be vectors for these intracellular bacteria. A complete sanitation of the incriminated drinking water system was accomplished by combined chemical and thermic disinfection measures.

Generation of Pseudomonas aeruginosa aerosols during handwashing from contaminated sink drains, transmission to hands of hospital personnel, and its prevention by use of a new heating device.

Abstract: Pseudomonas aeruginosa was isolated from sinks of washing basins, showers, toilets and bathtubs, from the personnel and patients of a mixed infectious disease ward in a German children's hospital during a prospective 4-week epidemiological study. 81% of all sinks were contaminated with P. aeruginosa strains. Upon entering the hospital, all personnel hand cultures were P. aeruginosa-negative. However, during duty, 42.5% of the personnel members carried different P. aeruginosa strains on their hands. Detection of P. aeruginosa strains in sinks preceding the isolation of identical genotypes from personnel hands suggested a transmission route from sinks to hands. Opening of water taps generated aerosols containing P. aeruginosa sink organisms which contaminated hands during hand washing. Survival times of various P. aeruginosa strains in aerosols was dependent on strain characteristics, light and humidity, and t 1/2 differed between 3-76 min. Heating of washing basin sinks to 70 degrees C with a new, safe and inexpensive device inhibited bacterial growth in sinks, generation of P. aeruginosa aerosols, and resulted in hand cultures negative for P. aeruginosa after washing.

Survival of E. coli and Salmonella populations in aerobic thermophilic composts as measured with DNA gene probes.

Abstract: Aerobic, thermophilic composting is a widely practiced method for disposal of organic wastes. The wastes which are composted include biosolids from waste water treatment plants (WWTP), and biowastes (food scraps and yardwaste). Important hygiene issues are involved in composting since many potential pathogens may be present in the fresh wastes. In this study, the survival of Salmonella and Escherichia coli is examined during aerobic composting of municipal solid wastes, municipal wastewater sludge and biowastes. A laboratory compost was prepared by inoculating with 10(7) Salmonella typhimurium Q and Escherichia coli B. In both industrial and laboratory trials, gene probes were used to determine at what time during the composting and at what temperature these bacteria became undetectable. It was observed that Salmonella and E. coli survived for 59 days at about 60 degrees C in an industrial compost. The bacteria became undetectable after the temperature decreased from 62 degrees C to about 40 degrees C in the compost curing. The bench scale trials showed that E. coli B survived for at least 9 days at 60-70 degrees C in a biowaste (food waste) compost or a waste water sludge compost. Salmonella typhimurium Q survived for at least 9 days over 60 degrees C in the food biowaste compost and at least 5 days in the waste water sludge compost. Data collected show that the temperature or the time of high temperature is difficult to correlate to the destruction of the pathogen, Salmonella, or the pathogen indicator, E. coli. These results suggest that the mechanism for removal of these microorganisms during aerobic composting is complex and not simply the result of a thermal physical environment.

Mycobacteria in biofilms

Abstract: The objective of this study was to elucidate the role of biofilms as the habitat of aquatic mycobacteria. Investigations were carried out on a biofilm which grew on the inner surface of a silicone tube constantly perfused by water of a distribution system known to be contaminated with Mycobacterium kansasii and M. flavescens. The biofilm yielded 2 x 10(5) cfu/cm2 of M. kansasii and 7 x 10(4) cfu/cm2 of M. flavescens after 10 months of perfusion. Microscopic examination revealed that approximately 1/4 to 1/3 of the biofilm organisms visualized by the Ziehl-Neelsen procedure were acid-fast bacteria, most of which occurred in densely packed microcolonies. These findings indicate that biofilms are an important habitat and site for proliferation of aquatic mycobacteria. Biofilms may be an explanation for the problems of controlling mycobacterial contamination of water distribution systems by means of chemical disinfection.

Risk factors for Campylobacter enteritis in Switzerland.

Abstract: From February to December 1991, 167 sporadic cases of Campylobacter enteritis in Switzerland and 282 controls were enrolled in a case-control study using self-administered questionnaires. In the multivariate matched analysis, travel abroad was identified as the most important risk factor for an infection with Campylobacter (adjusted odds ratio [OR] = 21.2, 95% confidence interval [CI]7.6-56.2). Having foreign citizenship also increased the risk (OR = 6.7, 95% CI 1.3-34.5). Among food items consumed within five days before onset of illness, consumption of poultry liver was shown to be a risk factor (OR = 5.7, 95% CI 1.4-22.8), while the consumption of curd or cottage cheese lowered the risk (OR = 0.5, 95% CI 0.3-0.9). The unmatched analysis confirmed travel abroad and the consumption of poultry liver as risk factors and the consumption of curd or cottage cheese as being protective, and, in addition, identified the consumption of poultry as a risk factor (OR = 2.0, 95% CI 1.1-3.3). The study showed the feasibility of using self-administered questionnaires for this type of analysis. The method is logistically simple and reduces the cost of case-control studies.