Teresa Cuna

Legionella spp. and legionellosis in southeastern Italy: disease epidemiology and environmental surveillance in community and health care facilities

BackgroundFollowing the publication of the Italian Guidelines for the control and prevention of legionellosis an environmental and clinical surveillance has been carried out in Southeastern Italy. The aim of the study is to identify the risk factors for the disease, so allowing better programming of the necessary prevention measures.MethodsDuring the period January 2000 - December 2009 the environmental surveillance was carried out by water sampling of 129 health care facilities (73 public and 56 private hospitals) and 533 buildings within the community (63 private apartments, 305 hotels, 19 offices, 4 churches, 116 gyms, 3 swimming pools and 23 schools). Water sampling and microbiological analysis were carried out following the Italian Guidelines. From January 2005, all facilities were subject to risk analysis through the use of a standardized report; the results were classified as good (G), medium (M) and bad (B). As well, all the clinical surveillance forms for legionellosis, which must be compiled by physicians and sent to the Regional Centre for Epidemiology (OER), were analyzed.ResultsLegionella spp. was found in 102 (79.1%) health care facilities and in 238 (44.7%) community buildings. The percentages for the contamination levels < 1,000, 1,000-10,000, > 10,000 cfu/L were respectively 33.1%, 53.4% and 13.5% for samples from health care facilities and 33.5%, 43.3% and 23.2% for samples from the community. Both in hospital and community environments, Legionella pneumophila serogroup (L. pn sg) 2-14 was the most frequently isolate (respectively 54.8% and 40.8% of positive samples), followed by L. pn sg 1 (respectively 31.3% and 33%). The study showed a significant association between M or B score at the risk analysis and Legionella spp. positive microbiological test results (p < 0.001). From clinical surveillance, during the period January 2001 - August 2009, 97 cases of legionellosis were reported to the OER: 88 of community origin and 9 nosocomial. The most frequent symptoms were: fever (93.8%), cough (70.1%), dyspnea (58.8%), shivering (56.7%). Radiological evidence of pneumonia was reported in 68%. The laboratory diagnostic methods used were: urinary antigen (54.3%), single antibody titer (19.8%), only seroconversion (11.1%), other diagnostic methods (14.8%).ConclusionsOur experience suggests that risk analysis and environmental microbiological surveillance should be carried out more frequently to control the environmental spread of Legionella spp. Furthermore, the laboratory diagnosis of legionellosis cannot be excluded only on the basis of a single negative test: some patients were positive to only one of the diagnostic tests.

Bloodstream infections by Malassezia and Candida species in critical care patients

Despite being considered an emerging yeast related to immunocompromised individuals, severe infections by Malassezia furfur have not been evaluated. During a one-year survey on yeasts fungemia, 290 neonatal and 17 pediatric patients with intravascular catheters, lipid parenteral nutrition, prolonged ward stay, and surgery were enrolled. In addition, the origin of the infection was investigated by swabbing hand skin of patients, parents, and healthcare workers and medical devices. All biological specimens and swabs were cultured on Sabouraud dextrose agar and Dixon agar. The yeasts identification was based on morphological and biochemical features and by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and confirmed by sequencing the internal transcribed spacer of nuclear ribosomal DNA. A higher prevalence of M. furfur (2.1%) over Candida spp. (1.4%) caused bloodstream infections (BSIs). Twelve fungemia episodes were recorded: 2 by M. furfur in a pediatric ward and 10 in a neonatal intensive care unit (6 caused by M. furfur and 4 by Candida spp.). M. furfur was also isolated from the skin of all patients with BSIs, from the hand skin of a parent, and from an incubator surface and sheet. Patients with Candida spp. and M. furfur BSIs were successfully treated with intravenous liposomal Amphotericin B. These findings highlight the need for a more accurate etiological diagnosis in high-risk patients by adding lipid-supplemented culture media for Malassezia in the current mycological routine as the clinical features, patient management, and outcomes in both Candida and Malassezia fungemia do not differ.

Comparative Evaluation of the Vitek 2 Yeast Susceptibility Test and CLSI Broth Microdilution Reference Method for Testing Antifungal Susceptibility of Invasive Fungal Isolates in Italy: the GISIA3 Study

ABSTRACT The newly available AST-YS01 Vitek 2 cards were evaluated, and the results were compared with those obtained by the CLSI M27-A2 microdilution reference method. Clinical fungal isolates, including 614 isolates of Candida spp., 10 Cryptococcus neoformans isolates, 1 Geotrichum capitatum isolate, and 2 quality control strains, were tested for their susceptibilities to amphotericin B, fluconazole, and voriconazole using both methods. The majority of fungal isolates were susceptible to all antifungal agents tested: the MIC90 values determined by the Vitek 2 and CLSI methods were 0.5 and 1 μg/ml, respectively, for amphotericin B; 8 and 16 μg/ml, respectively, for fluconazole; and <0.12 and 0.25 μg/ml, respectively, for voriconazole. Overall there was excellent categorical agreement (CA) between the methods (99.5% for amphotericin B, 92% for fluconazole, 98.2% for voriconazole), but discrepancies were observed within species. The CAs for fluconazole were low for Candida glabrata and Candida krusei when the results of the CLSI method at 48 h were considered. Moreover, the fully automated commercial system did not detect the susceptibility of Cryptococcus neoformans to voriconazole. The Vitek 2 system can be considered a valid support for antifungal susceptibility testing of fungi, but testing of susceptibility to agents not included in the system (e.g., echinocandins and posaconazole) should be performed with other methods.

Comparative evaluation of the Vitek 2 yeast susceptibility test and CLSI broth microdilution reference method for antifungal susceptibility testing of invasive yeast isolates in Italy: the GISIA3 study

ABSTRACT The newly available AST-YS01 Vitek 2 cards were evaluated, and the results were compared with those obtained by the CLSI M27-A2 microdilution reference method. Clinical fungal isolates, including 614 isolates of Candida spp., 10 Cryptococcus neoformans isolates, 1 Geotrichum capitatum isolate, and 2 quality control strains, were tested for their susceptibilities to amphotericin B, fluconazole, and voriconazole using both methods. The majority of fungal isolates were susceptible to all antifungal agents tested: the MIC90 values determined by the Vitek 2 and CLSI methods were 0.5 and 1 μg/ml, respectively, for amphotericin B; 8 and 16 μg/ml, respectively, for fluconazole; and <0.12 and 0.25 μg/ml, respectively, for voriconazole. Overall there was excellent categorical agreement (CA) between the methods (99.5% for amphotericin B, 92% for fluconazole, 98.2% for voriconazole), but discrepancies were observed within species. The CAs for fluconazole were low for Candida glabrata and Candida krusei when the results of the CLSI method at 48 h were considered. Moreover, the fully automated commercial system did not detect the susceptibility of Cryptococcus neoformans to voriconazole. The Vitek 2 system can be considered a valid support for antifungal susceptibility testing of fungi, but testing of susceptibility to agents not included in the system (e.g., echinocandins and posaconazole) should be performed with other methods.

A multicenter study of viable PCR using propidium monoazide to detect Legionella in water samples

Legionella quantification in environmental samples is overestimated by qPCR. Combination with a viable dye, such as Propidium monoazide (PMA), could make qPCR (named then vPCR) very reliable. In this multicentre study 717 artificial water samples, spiked with fixed concentrations of Legionella and interfering bacterial flora, were analysed by qPCR, vPCR and culture and data were compared by statistical analysis. A heat-treatment at 55 °C for 10 minutes was also performed to obtain viable and not-viable bacteria. When data of vPCR were compared with those of culture and qPCR, statistical analysis showed significant differences (P < 0.001). However, although the heat-treatment caused an abatement of CFU/mL ≤1 to 1 log10 unit, the comparison between untreated and heat-treated samples analysed by vPCR highlighted non-significant differences (P > 0.05). Overall this study provided a good experimental reproducibility of vPCR but also highlighted limits of PMA in the discriminating capability of dead and live bacteria, making vPCR not completely reliable.