Search

We study the completion problem for simple k-Latin rectangles, which are a special case of the generalized latin rectangles studied for which embedding theorems are given by Andersen and Hilton (1980) in “Generalized Latin rectangles II: Embedding”, Discrete Mathematics 31(3). Here an alternative proof of those theorems are given for k-Latin rectangles in the “simple” case. More precisely, generalizing two classic results on the completability of partial Latin squares, we prove the necessary and suffisucient conditions for a completion of a simple m x n k-Latin rectangle to a simple k-Latin square of order n and we show that if m ≤ n/2, any simple partial k-Latin square P of order m embeds in a simple k-Latin square L of order n.

The microbiological quality of marketable ready-to-eat (RTE) salads was discussed in terms of Public Health concerns. Since RTE foods are edible without additional treatment, risks of foodborne outbreaks may be high. The initial quality and subsequent handling of these products appear to influence their microbiological safety and shelf life. The authors evaluated the microbiological quality of marketable RTE salads. A total of 100 samples of RTE mixed salads were collected from local supermarkets in Catania (Italy). The RTE packages were immediately transported to the laboratory and analyzed according to the international standard methods (ISO) for aerobic mesophilic count (AMC at 30°C), Escherichia coli, coliforms, Salmonella and Listeria monocytogenes. All the samples (100%) were positive for AMC (median concentrations 106-107 CFU/g), 25.00% were positive for coliforms (median concentrations 104-105 CFU/g) and 10.00% for E. coli (median concentrations

The aim of the present study was to ascertain frequency and persistence of Candida spp. oral and urinary carriage in asymptomatic, HAART-naive HIV-seropositive subjects who had not undergone therapy with antimycotic drugs, and whose CD4+ lymphocyte count was greater than 200/microl. Oral carriage was the most common Candida spp. carriage (63.0% of the subjects), while candiduria was more rarely observed (6.5%). C. albicans was recovered from the majority of the subjects examined (56.5%), followed by C. krusey (4.3%), C. tropicalis (2.2%) and C. dubliniensis (2.2%). C. albicans was also isolated from two urinary carriers (4.3%) and C. glabrata from another one (2.2%). The same C. albicans clone was repeatedly isolated from 14 out of 15 oral carriers while the same clone of C. dubliniensis was repeatedly isolated from one carrier, as shown by the persistence of RAPD fingerprint of serial isolates during one year of follow-up. Since persistence of Candida spp. carriage may influence the development of clinical candidiasis in immunocompromised hosts, monitoring of the carrier status could be useful for preventing clinical thrush in HIV-seropositive subjects.

This study evaluated the presence and extent of contamination with Legionella spp. in the hot water distribution systems of three hospitals in Catania (Italy). In total, 291 hot water samples were collected between September 2002 and August 2005 and these were examined in order to monitor the hospital distribution systems and evaluate the efficacy of decontamination measures. L. pneumophila was detected at variable concentrations up to over 10000 UFC/L at several collection sites in some hospital buildings and branches of the water distribution system while other buildings/branches were found to be free of contamination. The most frequently isolated serogroup was L. pneumophila serogroup 3, occasionally associated with serogroups 4, 5 and 6. Molecular typing of Legionella strains by pulsed-field gel electrophoresis of genomic DNA restriction fragments identified four different genotypes, each recovered from a different branch of the distribution system. Decontamination procedures, including shock hyperchloration and two different thermal shock methods, performed between October 2003 and August 2005, led to only temporary reductions in contamination. In fact, previous concentrations of the same L. pneumophila serogroup were found within 3 to 8 months of decontamination. In order to prevent and monitor Legionella infections, sterilizing filters were installed in water taps of all wards with high-risk patients and urinary antigen testing was performed on all patients diagnosed with nosocomial pneumonia. No cases of Legionella pneumonia were identified in 2005.