M.T. Fera

New triazoles and echinocandins: mode of action, in vitro activity and mechanisms of resistance

Different types of mycoses, especially invasive mycoses caused by yeasts and molds, are a growing problem in healthcare. The most notable explanation for this increase is a rise in the number of immunocompromised patients owing to advances in transplantation, the emergence of AIDS and a rise in the number of invasive surgical procedures. Despite advances in medical practice, some therapeutic problems remain. In addition, intrinsic or acquired antifungal resistance may pose a serious problem to antifungal therapy. A new generation of triazole agents (voriconazole, posaconazole, isavuconazole, ravuconazole and albaconazole) and the recent class of the echinocandins (caspofungin, micafungin and anidulafungin) have become available, and represent an alternative to conventional antifungals for serious fungal infection management. Currently, only two of the recent triazole generation (voriconazole and posaconazole) and all three echinocandins are available for clinical use. More precisely, voriconazole and posaconazole are indicated for the treatment of invasive fungal infections and the echinocandins for the treatment of specific candidiasis. Voriconazole and posaconazole have a very broad spectrum of antifungal activity that includes Candida species, and filamentous and dimorphic fungi. Their activity extends to both fluconazole- and itraconazole-resistant strains of Candida. A major difference between posaconazole and voriconazole is that posaconazole has activity against Zygomycetes including Mucor spp., Rhizopus spp. and Cunninghamella spp., and voriconazole has no activity against this class of fungi. Ravuconazole, isavuconazole and albaconazole have shown very potent in vitro activity against species of Candida, Cryptococcus and Aspergillus, and they are currently in various stages of development. All three echinocandin agents, caspofungin, micafungin and anidulafungin, are similar in their spectrum of activity. Echinocandins do not possess in vitro activity against important basidiomycetes, including Cryptococcus, Rhodotorula and Trichosporon. This review attempts to deliver the most up-to-date knowledge on the mode of action and mechanisms of resistance to triazoles and echinocandins in fungal pathogens. In addition, the in vitro activity data available on triazoles and echinocandins are reported.

Distribution of potentially pathogenic bacteria as free living and plankton associated in a marine coastal zone

Aims:  To determine the abundance of faecal and nonfaecal bacteria related to human and animal health, as free living or associated with small (>64 μm) and large (>200 μm) plankton, samples were collected monthly from the coastal zone at Messina (Italy).

Detection of Arcobacter spp. in the Coastal Environment of the Mediterranean Sea

ABSTRACT The occurrence of Arcobacter spp. was studied in seawater and plankton samples collected from the Straits of Messina, Italy, during an annual period of observation by using cultural and molecular techniques. A PCR assay with three pairs of primers targeting the 16S and 23S rRNA genes was used for detection and identification of Arcobacter butzleri, Arcobacter cryaerophilus, and Arcobacter skirrowii in cultures and environmental samples. Only one of the Arcobacter species, A. butzleri, was isolated from seawater and plankton samples. With some samples the A. butzleri PCR assay gave amplified products when cultures were negative. A. cryaerophilus and A. skirrowii were never detected by culture on selective agar plates; they were detected only by PCR performed directly with environmental samples. Collectively, our data suggest that culturable and nonculturable forms of Arcobacter are present in marine environments. The assay was useful for detecting Arcobacter spp. both as free forms and intimately associated with plankton. This is the first report showing both direct isolation of A. butzleri and the presence of nonculturable Arcobacter spp. in the coastal environment of the Mediterranean Sea.

In vitro susceptibility of Arcobacter butzleri and Arcobacter cryaerophilus to different antimicrobial agents.

Seventeen strains of Arcobacter butzleri and thirteen of Arcobacter cryaerophilus, were tested for their antimicrobial susceptibility to 26 antimicrobial agents. Among beta-lactams agents in this study, imipenem was the most active agent against both A. butzleri and A. cryaerophilus isolates with MIC(90) values of 2 and 4 mg/l, respectively. The most active cephalosporin tested was cefepime, although it was more active against A. butzleri (MIC(90) 8 mg/l) than A. cryaerophilus (MIC(90) 64 mg/l). Levofloxacin, marbofloxacin, enrofloxacin and ciprofloxacin were the best-performing fluoroquinolones against these species. Of the aminoglycosides, amikacin was the most active agent against both A. butzleri and A. cryaerophilus strains with MIC(90) values of 64 and 16 mg/l, respectively. All isolates showed high levels of resistance to penicillins, macrolides, chloramphenicol, trimethoprim and vancomycin.

Pet cats as carriers of Arcobacter spp. in Southern Italy

Aims:  To evaluate the presence of Arcobacter spp. in different biological samples from domestic cats in Southern Italy by using a species‐specific PCR assay and thus to elucidate their potential significance as sources of human infection.

Occurrence of Helicobacter pylori DNA in the coastal environment of southern Italy (Straits of Messina)

Aims:  The occurrence of Helicobacter pylori in the coastal zone of the Straits of Messina (Italy) as free‐living and associated with plankton was studied.

New and Investigational Triazole Agents for the Treatment of Invasive Fungal Infections

Abstract The incidence of invasive fungal infections (IFIs) caused by both common and uncommon opportunistic fungi is increasing along with emerging fungal resistance. Since traditional agents (amphotericin B, fluconazole, itraconazole) are limited by an inade-quate spectrum of activity, drug resistance or toxicity, there is a great interest in the development of new antifungal agents for treatment of IFIs in high-risk populations. In recent years a number of systemic antifungal drugs have become available and options for treatment of IFIs have expanded. A new generation of triazole agents (voriconazole, posaconazole, isavuconazole, ravuconazole and albaconazole), with a broad spectrum of activity and sufficient improvements in potency to overcome resistance have emerged and represent an alternative to conventional antifungals for the prevention and treatment of IFIs. This article focuses on the microbiology, pharmacology, clinical efficacy and safety of the new antifungal triazole generation.

Induction and Resuscitation of Viable Nonculturable Arcobacter butzleri Cells

ABSTRACT Two strains of Arcobacter butzleri, ATCC 49616 and an environmental isolate, became nonculturable in seawater microcosms at 4°C by 20 days and at room temperature by 14 days. Nonculturable cells were viable for up to 270 days of incubation in microcosms. Resuscitation of A. butzleri cells from microcosms at both temperatures was achieved 9 days after nutrient addition.

Specific detection of Arcobacter spp. in estuarine waters of Southern Italy by PCR and fluorescent in situ hybridization.

Aim:  To evaluate the reliability of culture‐independent methods in comparison with culture‐dependent ones for the detection of Arcobacter spp. in estuarine waters of Southern Italy.

Adherence of environmental Arcobacter butzleri and Vibrio spp. isolates to epithelial cells in vitro

The objective of this study was to explore the ability of environmental Arcobacter butzleri and Vibrio spp. strains to adhere and induce cytotoxicity in cultured epithelial cells. A total of 27 of marine environment isolates, 17 A. butzleri and 10 Vibrio spp., were tested individually for the adhesive capacity to HEp-2 and HeLa line cells. Next, the ability of these strains to secrete toxic factors capable of producing morphological changes on Vero cells, was tested. Only six out of 17 of the A. butzleri strains were able to adhere to both cell lines. 57% of the V. alginolyticus strains were able to adhere to HEp-2 and HeLa cell lines. None of the Vibrio strains produced toxic factors. However, five out of the six of the A. butzleri strains that were shown to adhere both cell lines, also secreted toxic factors. It is apparent from this study that toxigenic and adhesive strains of A. butzleri can be isolated from aquatic environments in Messina (Italy).