Giuseppina Caggiano

Environmental distribution of Cryptococcus neoformans and C. gattii around the Mediterranean basin

In order to elucidate the distribution of Cryptococcus neoformans and C. gattii in the Mediterranean basin, an extensive environmental survey was carried out during 2012-2015. A total of 302 sites located in 12 countries were sampled, 6436 samples from 3765 trees were collected and 5% of trees were found to be colonized by cryptococcal yeasts. Cryptococcus neoformans was isolated from 177 trees and C. gattii from 13. Cryptococcus neoformans colonized 27% of Ceratonia, 10% of Olea, Platanus and Prunus trees and a lower percentage of other tree genera. The 13 C. gattii isolates were collected from five Eucalyptus, four Ceratonia, two Pinus and two Olea trees. Cryptococcus neoformans was distributed all around the Mediterranean basin, whereas C. gattii was isolated in Greece, Southern Italy and Spain, in agreement with previous findings from both clinical and environmental sources. Among C. neoformans isolates, VNI was the prevalent molecular type but VNII, VNIV and VNIII hybrid strains were also isolated. With the exception of a single VGIV isolate, all C. gattii isolates were VGI. The results confirmed the presence of both Cryptococcus species in the Mediterranean environment, and showed that both carob and olive trees represent an important niche for these yeasts.

Invasive fungal infections in patients with hematologic malignancies (aurora project): lights and shadows during 18-months surveillance.

The aim of this multicenter prospective study was to evaluate the incidence of invasive fungal infections (IFIs) in adult and pediatric patients with hematologic malignancies, involving nine nosocomial facilities in Southern Italy over a period of 18 months. Furthermore, results of an environmental microbial surveillance routinely carried out in some of the enrolled hospitals are reported. A total of 589 onco-hematological patients were enrolled and 27 IFIs were documented. The main infections were caused by yeasts, more than filamentous fungi (overall incidence of 2.7% and 1.9%, respectively). The yeasts were mainly represented by Candida spp. (87.5%), all isolated by blood cultures; C. parapsilosis was the most common species. Among mould infections, the most frequent site was the lung, with regard to aspergillosis (81.8%). In six of the 10 patients with suspected aspergillosis, the diagnosis was made by the detection of galactomannan and (1,3)-β-d-glucan antigens. The microbiological surveillance carried out on 156 air, 312 water and 312 surface samples revealed low environmental contamination: Alternaria alternata was the only fungus isolated from two surface samples. Our data, especially the low occurrence of filamentous fungi, suggest a particular local epidemiology. Further studies are needed to confirm this microbiological trend in onco-hematological patients in Southern Italy, the results of which might be helpful to improve the management of these patients.

Candida Bloodstream Infections in Italy: Changing Epidemiology during 16 Years of Surveillance

Although considerable progress has been made in the management of patients with invasive fungal infections, Candida bloodstream infections are still widespread in hospital settings. Incidence rates vary geographically, often because of different patient populations. The aim of the present study was to describe the epidemiology of candidemia, to analyze the trend of species distribution, and to measure the in vitro susceptibility to antifungal drugs in a university Italian hospital from 1998 to 2013. The antifungal susceptibility for all Candida isolates was evaluated by broth microdilution assay (CLSI M27-A3 document). Of 394 episodes of candidemia, the average incidence was 3.06/10 000 admissions. C. albicans and non-albicans Candida species caused 44.2% and 55.8% of the episodes, respectively. C. parapsilosis (62.2%) was the most common non-albicans.   C. albicans predominated in almost all departments whereas C. parapsilosis was found in adult and paediatric oncohaematology units (34.8% and 77.6%, resp.). Overall, mortality occurred in 111 (28.2%) patients. Death occurred most often in intensive care units (47.1%) and specialist surgeries (43.7%). Most of the isolates were susceptible to antifungal drugs, but there was an upward trend for azole (P < 0.05). In conclusion, this study emphasizes the importance of monitoring local epidemiologic data and the diversity of patient groups affected.

Diagnostic Performance of 1→3-β-D-Glucan in Neonatal and Pediatric Patients with Candidemia

Fungal sepsis is one of the major problems in neonatal and pediatric care unit settings. The availability of new diagnostic techniques could allow medical practitioners to rapidly identify septic patients and to improve their outcome. The aim of this study was to evaluate the performance of the 1→3-β-d-glucan (BDG), individually and in comparison with the Candida mannan (CM) antigen, in ten preterm infants and five onco-haematological pediatric patients with Candida bloodstream infections already proven by positive culture. The serum levels of BDG were >80 pg/mL on the same day as a positive blood culture in all examined patients, while CM antigen was negative in the patients with C. parapsilosis fungemia and in one further case due to C. albicans. These results suggest that a regular monitoring of serum circulating antigens (i.e., 1→3-β-d-glucan) combined with other microbiological and clinical information, may allow earlier and accurate diagnosis. However, further studies are necessary to confirm its usefulness in routine clinical practice.

Observational study on candidaemia at a university hospital in southern Italy from 1998 to 2004

In an observational study on candidaemia in hospitalised patients, conducted in a southern Italy hospital during 1998–2004, 155 cases were noted. Candida albicans (CA) was isolated in 71 (45.8%) cases involving mainly patients recovered in ICU, General Surgery and Neonatology. Candida non‐albicans (CnA) species were isolated by 84 (54.2%) candidaemic patients, and in particular, Candida parapsilosis was the most frequent species isolated in Pediatric Oncology. 91.6% of the patients had a central venous catheter and only 46.4% were receiving antifungal prophylaxis. Among these patients, 87.5% (63) developed CnA infections; in particular, 41 patients had a C. parapsilosis bloodstream infection. During our study, we observed a variable drift from 1998 to 2003; we registered an evident increment of CnA candidaemia (76.9%) and a decrease of CA cases (23%) only in 2004. The mortality was 26.7%, and we observed that CA was associated with the highest rate of mortality (53.6%). Although Candida infections are correlated primarily with risk factors, their resolution depends on timely diagnosis and early therapy.

Candida Colonization Index in Patients Admitted to an ICU

Multiple-site colonization with Candida spp. is commonly recognized as a risk factor for invasive fungal infection in critically ill patients. We carried out a study to determine the relationship between Candida colonization and invasive infection in neurological patients admitted to an ICU. At admission (T0) and every three days for two weeks, different samples (pharynx swab, tracheal secretions, stomach contents, etc.) were collected for mycological surveillance. Candida mannan antigen and Candida anti-mannan antibodies were assayed. The Colonization Index (CI) and Corrected Colonization Index were calculated for each time point. Of all patients 70% was already colonized by Candida spp. at T0 and six of them had CI ≥ 0.5. Three patients developed candidemia; they had CI ≥ 0.5 before infection. Positive values of Candida mannan antigen and anti-mannan antibodies were found only in the patients with candidemia. The sensitivity and specificity of the Candida mannan test were 66.6% and 100%, respectively, while the sensitivity and specificity of the anti-mannan antibody test were 100%. In accordance with other authors, we find the surveillance cultures are useful to monitor the Candida colonization in ICU patients. In addition, the sequential observation of anti-mannan antibodies could contribute to early diagnosis of candidiasis more than Candida mannan antigen in immunocompetent patients.

Oral nystatin prophylaxis in surgical/trauma ICU patients: a randomised clinical trial

IntroductionCandida prophylaxis in ICU is still a matter of debate. Oral chemoprophylaxis has been advocated to reduce the incidence of Candida colonisation and infection.MethodsWe performed a randomised trial studying a single drug (nystatin) versus control in surgical/trauma ICU patients. Multiple-site testing for fungi was performed in each patient on ICU admission (T0) and subsequently every 3 days (T3, T6, T9, and so forth). The primary evaluation criterion was the time course of the corrected colonisation index.ResultsNinety-nine patients were enrolled. At admission, 69 patients exhibited Candida colonisation: the most frequently colonised body sites were the stomach and the pharynx. The most frequent isolated species was Candida albicans. The corrected colonisation index was similar in the two groups at T0 (P = 0.36), while a significant statistical difference was observed between the treatment and control groups at T6 (median 0.14 and 0.33, respectively; P = 0.0016), at T9 (median 0.00 and 0.28, respectively; P = 0.0001), at T12 (median 0.00 and 0.41, respectively; P = 0.0008), and at T15 (median 0.00 and 0.42, respectively; P < 0.0003). The same results were obtained in the subgroup of patients already colonised at ICU admission.ConclusionThis trial shows that nystatin prophylaxis significantly reduces fungal colonisation in surgical/trauma ICU patients, even if already colonised.Trial registrationClinicalTrials.gov: NCT01495039

The role of the laboratory in the diagnosis of invasive candidiasis.

A diagnosis of invasive candidiasis can be achieved using conventional approaches (microscopy, culture, serology), as well as new methods, including antigen detection and polymerase chain reaction (PCR) assays. Most of the conventional approaches lack sensitivity, especially for obtaining a diagnosis of invasive candidiasis in immunocompromised patients. Antigen detection and PCR assays represent a valid alternative, in terms of their high potential sensitivity and specificity, but these procedures still need to be standardized and evaluated in a large number of patients.

In vitro activities of amphotericin B deoxycholate and liposomal amphotericin B against 604 clinical yeast isolates

We determined the in vitro antifungal activity of liposomal amphotericin B (L-AmB) against 604 clinical yeast isolates. Amphotericin B deoxycholate (D-AmB) was tested in parallel against all the isolates. Susceptibility testing was performed according to the Clinical and Laboratory Standards Institute (CLSI) M27-A3 method. Overall, L-AmB was highly active against the isolates (mean MIC, 0.42 µg ml−1; MIC90, 1 µg ml−1; 97.2 % of MICs were ≤1 µg ml−1) and comparable to D-AmB (mean MIC, 0.48 µg ml−1; MIC90, 1 µg ml−1; 97.3 % of MICs were ≤1 µg ml−1). The in vitro activity of D-AmB and L-AmB was correlated (R2 = 0.61; exp(b), 2.3; 95 % CI, 2.19–2.44, P<0.001). Candida albicans (mean MICs of D-AmB and L-AmB, 0.39 µg ml−1 and 0.31 µg ml−1, respectively) and Candida parapsilosis (mean MICs of D-AmB and L-AmB, 0.38 µg ml−1 and 0.35 µg ml−1, respectively) were the species most susceptible to the agents tested, while Candida krusei (currently named Issatchenkia orientalis) (mean MICs of D-AmB and L-AmB, 1.27 µg ml−1 and 1.13 µg ml−1, respectively) was the least susceptible. The excellent in vitro activity of L-AmB may have important implications for empirical treatment approaches and support its role in treatment of a wide range of invasive infections due to yeasts.

Molecular Identification and Echinocandin Susceptibility of Candida parapsilosis Complex Bloodstream Isolates in Italy, 2007–2014

The Candida parapsilosis group encompasses three species: C. parapsilosis, C. orthopsilosis, and C. metapsilosis. Here, we describe the incidence and echinocandin susceptibility profile of bloodstream isolates of these three species collected from patients admitted to an Italian university hospital from 2007 to 2014. Molecular identification of cryptic species of the C. parapsilosis complex was performed using polymerase chain reaction amplification of the gene encoding secondary alcohol dehydrogenase, followed by digestion with the restriction enzyme BanI. Minimum inhibitory concentrations were determined using the broth microdilution method according to European Committee for Antimicrobial Susceptibility Testing (EUCAST EDef 7.2) and Clinical Laboratory Standards Institute (CLSI M27-A3) guidelines, and the results were compared with those obtained using the E-test and Sensititre methods. Of the 163 C. parapsilosis complex isolates, 136 (83.4%) were identified as C. parapsilosis, and 27 (16.6%) as C. orthopsilosis. The species-specific incidences were 2.9/10,000 admissions for C. parapsilosis and 0.6/10,000 admissions for C. orthopsilosis. No resistance to echinocandins was detected with any of the methods. The percent essential agreement (EA) between the EUCAST and E-test/Sensititre methods for anidulafungin, caspofungin, and micafungin susceptibility was, respectively, as follows: C. parapsilosis, 95.6/97.8, 98.5/88.2, and 93.4/96.3; C. orthopsilosis, 92.6/92.6, 96.3/77.8, and 63.0/66.7. The EA between the CLSI and E-test/Sensititre methods was, respectively, as follows: C. parapsilosis, 99.3/100, 98.5/89.0, and 96.3/98.5; C. orthopsilosis, 96.3/92.6, 100/81.5, and 92.6/88.9. Only minor discrepancies, ranging from 16.9% (C. parapsilosis) to 11.1% (C. orthopsilosis), were observed between the CLSI and E-test/Sensititre methods. In conclusion, this epidemiologic study shows a typical C. parapsilosis complex species distribution, no echinocandin resistance, and it reinforces the relevance of using commercially available microbiological methods to assess antifungal susceptibility. These data improve our knowledge of the national distribution of species of the psilosis group, as there are very few studies of these species in Italy.