New hosts for the mite Ornithonyssus bursa in Argentina.

The mite Ornithonyssus bursa (Berlese) (Mesostigmata: Macronyssidae) is considered a poultry pest causing important infestations in chickens and it is considered a potential vector of arbovirus. Despite being considered a common parasite in wild birds, there is scarce published information about its potential hosts and effects on them. Here we present new bird hosts for O. bursa, assess the presence of Alphavirus, Flavivirus and Bunyavirus in mites from three host species, and discuss its potential impact on wild bird populations. We found O. bursa infecting five raptor and six passerine wild bird species. For nine of these species, this is the first record of infection by O. bursa. Although all analysed mites were negative for the examined arboviruses, the small sample size of mites does not allow further conclusions at the present moment. Because of the general nature of this ectoparasite, its presence in migratory long dispersal and endangered bird species, and the seropositivity for arboviruses in some of the species studied here, we consider it critical to assess the role of O. bursa and other ectoparasites as vectors and reservoirs of pathogens and as potential deleterious agents in wild bird populations.

The application of cost effectiveness analysis to derive a formulary for urinary tract infections.

According to economic principles an inappropriate prescription is the choice of an antimicrobial with higher/equivalent cost and lower effectiveness (or higher cost and equivalent/lower efficacy) than an alternative (in this case, the former is specified as a "dominated" drug). To identify cost-effective antibiotics we applied the principles of incremental cost-effectiveness analysis (ICEA) to microbiological data of San Bortolo Hospital. Its 27 wards were grouped in 9 functional areas. The resistance patterns of 8 urinary pathogens in the 1997 microbiology data base were assessed. The measure of antibiotic effectiveness was expressed as the percentage of isolates susceptible to each antibiotic tested. The difference in cost (i.e. the incremental change) between each antibiotic and the next more expensive alternative was calculated, and compared with the incremental change in effectiveness. Calculations were made for each pathogen. The antibiotics remaining after exclusion of all "dominated" antibiotics were pooled on a list defined as "Specific Area Formulary". The implications of the use of economic principles within a general antimicrobial policy are discussed.

Three-times weekly teicoplanin in the outpatient treatment of acute methicillin-resistant staphylococcal osteomyelitis: a pilot study.

Treatment of osteomyelitis requires prolonged hospital stay, lengthy antibiotic therapy and adequate surgical debridement. Outpatient parenteral antibiotic therapy (OPAT) is a new approach to reduce patient discomfort and hospital costs. Teicoplanin, a glycopeptide antibiotic with a long half-life (72 hours), is one of the most useful drugs for OPAT. We performed a pilot study to assess the safety and efficacy of three-times weekly teicoplanin in the treatment of methicillin-resistant (MR) acute staphylococcal osteomyelitis. Ten patients with acute post-traumatic osteomyelitis were enrolled. Pathogens were MR Staphylococcus aureus (5 patients) and MR coagulase-negative staphylococci (5 patients). After a loading dose of 400 mg b.i.d. for 3 days, patients were treated with an intravenous dose of 1000 mg on Mondays and Wednesdays and with a 1200 mg dose on Fridays. Teicoplanin trough levels were maintained within a 10 to 20 mg/L range. If hardware removal had been possible at enrollment, treatment was carried out for at least 4 weeks. If, on the contrary, hardware removal had not been possible, teicoplanin was administered as suppressive therapy until hardware removal. Treatment was successfully performed in 9 out of 10 patients, whereas in one patient only improvement was achieved. Side effects were not recorded. Three times weekly teicoplanin seems to be a valuable option in the treatment of acute MR staphylococcal osteomyelitis. Further studies are warranted in order to better define the role of this new administration schedule in this field.

Epidemiological analysis of vancomycin-resistant enterococci in a large tertiary-care hospital in Northern Italy.

The epidemiology of vancomycin-resistant enterococci (VRE) was studied in a large tertiary-care hospital in northern Italy from February 1993 to December 1999. Sixteen cases of bacteraemic and 17 cases of nonbacteraemic active infections caused by VRE were recorded. Fifteen of the bacteraemic and four of the nonbacteraemic infections occurred in patients in the haematology department, while the remainder were registered in other departments of the same hospital. Active surveillance for the presence of VRE in stools led to identification of 51 noninfected carriers over the 1994-1999 period; of these, 32 were haematology patients and the remainder were patients admitted to other departments. All VRE isolates carried the vanA gene. Forty-one Enterococcus faecium isolates and eight Enterococcus faecalis isolates collected in the 1993-1996 period were typed by pulsed-field gel electrophoresis. Twenty-nine isolates of Enterococcus faecium shared either indistinguishable or strictly or possibly related patterns. Of these, 26 were isolated from patients in the haematology department. This is believed to be the first study on the epidemiology of VRE carried out in a large hospital in Italy over a period of several consecutive years. It reports an increase in VRE due to the epidemic spread of genetically related strains and sporadic infections or colonisation by unrelated VRE. It also documents the success of surveillance and of the measures adopted for preventing the spread of VRE in patients at risk.

Molecular analysis of vanA enterococci isolated from humans and animals in northeastern Italy.

A total of 53 vancomycin-resistant vanA-positive enterococci isolates from poultry farms (17 Enterococcus faecium; 8 Enterococcus durans) and from different hospitals (23 E. faecium; 5 Enterococcus faecalis) in northeastern Italy were compared on the basis of their antibiotic susceptibilities, their SmaI pulsed-field gel electrophoresis (PFGE) patterns, and the organization of their Tn1546-related elements. Ampicillin resistance was similar in both groups of isolates (52 and 60.7%, respectively), whereas human strains were more resistant to high-level gentamicin and streptomycin. A total of 52% of animal strains and 60% of human strains were resistant to tetracycline, and 56% and 46.4% to quinupristin/dalfopristin, respectively. In E. faecium and E. durans animal isolates, nine and six distinct PFGE patterns, respectively, were found: in two instances indistinguishable isolates were found from different farms. In E. faecium and E. faecalis human isolates, nine and six distinct PFGE patterns, respectively, were found; among E. faecium strains, 12 were identical or closely related and were isolates from the same hospital. Elements mediating vanA-glycopeptide resistance were characterized by PCR with primers that amplified 10 overlapping fragments of Tn1546. A total of 84.6% of animal strains and 64.2% of human strains contained elements indistinguishable from the prototype Tn1546. In addition, nine different types were identified, but none was common to animal and human strains.

[Setting priorities in the prevention and control of nosocomial infections: an economic perspective] / Definizione delle priorita e degli obiettivi nei programmi di prevenzione e controllo delle infezioni ospedaliere: il punto di vista economico.

Nosocomial infections are a good indicator of the quality of health care provided by hospitals. Despite their cost-effectiveness, nosocomial infection programs are rarely applied in Italy. Epidemiological surveillance is the simplest measure to adopt because it allows us to monitor the baseline endemic rates, identify new epidemics and assess the improvements achieved by interventions provided. The presence of continuous epidemiological surveillance must be considered the exception rather than the rule in Italy. In this paper, the prevention of nosocomial infections was analysed through two economic evaluation techniques (i.e. cost-benefit and cost effectiveness). A hierarchy of intervention based on cost effectiveness, hospital size and organisational setting was also provided. The main conclusions are the following: 1. Benefits associated to prevention of nosocomial infections are considered small because of the uncertainty associated to the future. Therefore a discount factor must be applied. 2. Local factors and specific reasons are usually advocated to explain the simple fact that infection control programs are only formally implemented and usually limited to the constitution of a nosocomial infections committee. 3. The prevention of nosocomial infections must be provided for under specific laws which take into account the various organisations and structures found in different hospitals.