Infections Control And Contamination Of Daily Use Objects

Main Category: MRSA / Drug Resistance
Also Included In: Infectious Diseases / Bacteria / Viruses
Article Date: 21 Apr 2008 - 3:00 PDT

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ECCMID Opening Press Conference. "Microorganisms are everywhere. Bacteria and fungi contaminate our body, our houses (i.e. bedrooms, kitchens, and toilets) but also workplaces, pets and the whole environment" - said Prof. Andreas Voss (Canisius-Wilhelmina Hospital, The Netherlands). Fortunately, among many billions of bacteria, only 1,500 can be dangerous for our health, causing different diseases such as pneumonia or skin infections. "The real problem is that the number of bacterial strains which develop resistances towards disinfectants and especially antibiotics is increasing very fast", pointed out Prof. Voss. "Some of these resistant microorganisms are difficult to destroy, and can survive for a longer time on the floor and other surfaces". "This is the reason why just five years ago it was absolutely rare to find resistant bacteria outside hospitals or nursing homes, while resistant bacterial strains are now spreading also to our houses and other places where people live, work or spend their free time together".

"It seems like there are no safe objects" stated Prof. Voss. "Tables, utensils, computers, door knobs, gym equipments and other objects were shown be contaminated with potentially dangerous pathogens. Bacterial presence has been revealed also on mobile phones, and even on the mouse and keyboard of personal computers. All these items and surfaces can be a potential source for cross infections, transmitting microorganisms". "While this is in general not a problem within the community, we should be aware of it within the healthcare setting. Therefore, we should promote regular decontamination of daily use objects as part of an effective strategy to prevent the spread of multi-resistant pathogens and the occurrence of consequent infections", concluded Prof. Voss.

Some of the pathogens that cause problems in the healthcare setting are furthermore of importance in many common situations of our daily life in the community. There is an increasing concern about fungal corneal infections among young people wearing soft contact lenses, despite the use of disinfecting solutions. This happens because - according to the Food and Drug Administration (FDA) guidelines - disinfecting solutions are tested only against Fusarium solani, but their effectiveness on other environmental fungal isolates is not routinely evaluated.

This could be dangerous as poor compliance with lenses care procedures and rubbing of the eyes can introduce fungi into the eye. According to a study conducted in Hong Kong (C. Ma, M.V Boost, and P. Cho - ECCMID abstract no.2661) on young people aged 20-24, environmental fungal isolates detectable on contact lenses were found to be partially resistant to the commonly used multipurpose disinfecting solutions, despite FDA guidelines for the test strain of Fusarium solani were always fulfilled. Penicillium (38%) and Aspergillus (30%) species were the fungi most frequently isolated, the latter being a dangerous ocular pathogen. "The failure of disinfecting solutions to successfully reduce the number of viable fungi may increase the risk of ocular infection of fungal etiology in contact lens wearers, thus underlining the importance of a strictly adherence to all the necessary hygiene practices", pointed out Prof. Voss.

Some circumstances, such as visits to the dentistry, could represent a possible chance of bacterial contamination, continued Prof. Voss. A study conducted in Turkey (I. Türetgen, D. Göksay, A. Cotuk - ECCMID abstract no.544) analyzed the total microbial load of the water systems used in 41 dental centers, documenting that 39 of them were not able to respect the limit of 200 CFU/ml (Colony Forming Units per milliliter), representing the maximum value for the quality of drinking water in many European countries. Furthermore, the presence of Legionella pneumophila bacterium (a respiratory pathogen, which is responsible for Legionnaires' Disease) was confirmed in 5 out of 41 dental centers, and water systems of eight centers (filled with bottled drinking water) were found to be heavily contaminated. A French study (carried out by A. Bousseau, E. Cateau et al. - ECCMID abstract no.1259) has confirmed the possible contamination of the water we use when undergoing dental procedures, with various organisms having been isolated: free living amoebae, Candida albicans, Legionella pneumophila, and Pseudomonas aeruginosa. "These results could enhance the attention concerning microbiological quality of dental centers' water systems", said Prof. Voss. "Even though we cannot assume those data as universally applicable, there is the need to regularly control the water systems at dental centers in order to ensure an acceptable microbiologic quality, as patients and dental staff can be exposed to contaminated water and aerosols".

Although the possibility of resistant bacteria transmission from animals to humans has been demonstrated in several studies and despite the number of infections which can be transmitted by domestic pets, resistant bacteria can be also spread from humans to animals and even kill our pets. An Italian study (conducted in Rome area by M. Corrente, M. D'Abramo, F. Latronico et al.. ECCMID abstract no.2634) has documented an outbreak of neonatal mortality in dogs, due to a methicillin-resistant Staphylococcus aureus (MRSA), and the possible role of their human owners as reservoirs of the infection which killed the pets.

The bacteriological analysis carried out in this study revealed the presence of MRSA in 12 pups who died within 10 days, presenting signs of severe septicaemia and multifocal hemorrhagic lesions in several organs. In order to investigate the source of the MRSA infection, bacteriological analyses were extended to the dogs and persons living in the household. Swabs from several parts of the body were taken from the parents of the pups, from the 2 owners (a man and his wife), and from a woman who occasionally looked after the animals. Both the man and this woman worked as medical attendants at the same hospital. The analyses succeeded in isolating MRSA in all the samples, for a total of 17 strains (resistant to more than 3 classes of antibiotics), while the genetic patterns of all the bacterial strains suggested a common origin. "In this study - said Prof. Voss - a single MRSA clone was isolated from dogs and humans living in the same household". Since two of the persons were healthcare professionals, and the dogs had no contact with other animals or persons, we can assume that resistant bacteria, carried from the hospital to the household, caused a fatal infection in the pets. "While this is an interesting case of human to animal transmission, the main future concern is the transmission of pathogens from animals to humans, especially if animals become a permanent source of multi-drug resistant pathogens, such as MRSA", concluded Prof. Voss.

"The rise of new zoonotic sources of MRSA may have a severe impact on the epidemiology of community acquired MRSA and negative consequences on the MRSA diffusion control", especially in those countries where the prevalence of this infection is currently low. "Survaillance programs should be started immediately, with the aim of identifying and destroying all new reservoirs". Several studies presented at ECCMID concern farm animals (especially pigs and calves) as a source of MRSA - a phenomenon first recognized in the Netherlands (and presented for the first time at ECCMID last year) that is now accepted in many European countries and internationally.

Overall 25% of humans are likely to carry S. aureus, but this colonization may be transient or persistent. However, the incidence of S. aureus carriage has been documented to be higher in health care workers (HCW) and their families. In a study conducted analyzing cultures of nasal swabs, D. Lo, M.V. Boost and colleagues (ECCMID abstract no.740) have shown that 11.4% of 342 health care workers' relatives were persistently colonized by MRSA, 26.9% only transiently colonized, and 61.7% have never been infected. Persistent carriage resulted more common in HCW relatives aged <10 or >60 years old. Two families consisted only of persistent carriers, while in 29 families were detected only non-carriers subjects. Mothers/spouses were the most frequently colonized family members. In sixteen out of 57 HCW families with one or more colonized members, at least another family member was positive to the same MRSA strain. MRSA colonization remained low in families with no health care workers (range 0.3-1.1%). Two cases of MRSA transmission between mothers and sons were confirmed. As a strong relationship with objects' and hands' contamination has been demonstrated, hand hygiene might decrease healthcare-associated infection rates. "Hands hygiene still remains the single most effective measure to reduce infections related to healthcare workers' activity, even if epidemic diffusion of new bacterial strains requires more specific precautions".

Over the years researchers have tried various methods to increase hands hygiene compliance among health-care workers, that even include the successful use of "promotional toilet paper" as a reminder to healthcare-workers to disinfect their hands. Despite that, a recent study involving almost 300 health care workers (F. Verhoeven et al. - ECCMID abstract no.1187) showed inadequate levels of knowledge (97%) and risk perception (24%) about safe work practices, and negative attitudes (63%) toward complying with these practices. The lack of knowledge was also related to misinformation about MRSA transmission routes (14%), and negative attitudes were caused by HCWs questioning the usefulness of adhering to safe work practices (14%). "These factors lead to non-compliance with safe work practices, which must be improved especially among people working at hospitals or nursing homes", concluded Prof. Voss

European Congress of Clinical Microbiology and Infectious Diseases