The Threat Called Candida haemulonii Species Complex in Rio de Janeiro State, Brazil: Focus on Antifungal Resistance and Virulence Attributes.

Although considered rare, the emergent Candida haemulonii species complex, formed by C. haemulonii sensu stricto (Ch), C. duobushaemulonii (Cd) and C. haemulonii var. vulnera (Chv), is highlighted due to its profile of increased resistance to the available antifungal drugs. In the present work, 25 clinical isolates, recovered from human infections during 2011-2020 and biochemically identified by automated system as C. haemulonii, were initially assessed by molecular methods (amplification and sequencing of ITS1-5.8S-ITS2 gene) for precise species identification. Subsequently, the antifungal susceptibility of planktonic cells, biofilm formation and susceptibility of biofilms to antifungal drugs and the secretion of key molecules, such as hydrolytic enzymes, hemolysins and siderophores, were evaluated by classical methodologies. Our results revealed that 7 (28%) isolates were molecularly identified as Ch, 7 (28%) as Chv and 11 (44%) as Cd. Sixteen (64%) fungal isolates were recovered from blood. Regarding the antifungal susceptibility test, the planktonic cells were resistant to (i) fluconazole (100% of Ch and Chv, and 72.7% of Cd isolates), itraconazole and voriconazole (85.7% of Ch and Chv, and 72.7% of Cd isolates); (ii) no breakpoints were defined for posaconazole, but high MICs were observed for 85.7% of Ch and Chv, and 72.7% of Cd isolates; (iii) all isolates were resistant to amphotericin B; and (iv) all isolates were susceptible to echinocandins (except for one isolate of Cd) and to flucytosine (except for two isolates of Cd). Biofilm is a well-known virulence and resistant structure in Candida species, including the C. haemulonii complex. Herein, we showed that all isolates were able to form viable biofilms over a polystyrene surface. Moreover, the mature biofilms formed by the C. haemulonii species complex presented a higher antifungal-resistant profile than their planktonic counterparts. Secreted molecules associated with virulence were also detected in our fungal collection: 100% of the isolates yielded aspartic proteases, hemolysins and siderophores as well as phospholipase (92%), esterase (80%), phytase (80%), and caseinase (76%) activities. Our results reinforce the multidrug resistance profile of the C. haemulonii species complex, including Brazilian clinical isolates, as well as their ability to produce important virulence attributes such as biofilms and different classes of hydrolytic enzymes, hemolysins and siderophores, which typically present a strain-dependent profile.

Ceftazidime-Avibactam as Salvage Therapy for Infections Caused by Enterobacteriales Coresistant to Carbapenems and Polymyxins.

In this article, we report a case series of patients with infections caused by Enterobacteriales coresistant to carbapenems and polymyxins who were treated with ceftazidime/avibactam (CAZ-AVI) salvage therapy on a compassionate-use protocol. We enrolled 29 adult patients in 3 centers that had an infection due to a resistant microorganism and for whom the treatments available were considered ineffective, treated them with CAZ-AVI, and assessed clinical and microbiological cure at the end of treatment and all-cause mortality at 14 days and 30 days. The antimicrobial susceptibility profile was determined using broth microdilution, and total genomic DNA was sequenced. Twelve (41.4%) patients had bacteremia, and 48.3% (14/29) of the infections were treated with combination therapy. All strains were producers of KPC-2 and were susceptible to CAZ-AVI (MIC90, 1 µg/ml). Clinical success was high (24/29 [82.7%; 95% confidence interval, 64.2 to 94.2%]), even for the bacteremic cases (75%). The 14-day and 30-day mortality rates were 9/29 (31%) and 15/29 (51.7%), respectively. The 14-day mortality rate for pneumonia was the same as that for bloodstream infections (33.3%) and although not significant, we found that patients with renal impairment that received adjusted doses of CAZ-AVI had high mortality (4/9 [44%]; P = 0.22). We concluded that CAZ-AVI is an option for the treatment of severe infections due to difficult-to-treat drug-resistant Enterobacteriales.

Mupirocin for controlling methicillin-resistant Staphylococcus aureus: lessons from a decade of use at a university hospital.

BACKGROUND: From 1990 to 1995 at Hospital Universitário Clementino Fraga Filho, patients colonized or infected with methicillin-resistant Staphylococcus aureus (MRSA) were treated with mupirocin to eliminate MRSA carriage. In 1995, 65% of MRSA patients at this hospital had mupirocin-resistant isolates. Starting in 1996, mupirocin use was restricted to patients colonized, but not infected, with MRSA. OBJECTIVES: To describe the use of mupirocin for controlling MRSA over a decade and to analyze the molecular epidemiology of mupirocin-resistant MRSA infections at this hospital. SETTING: A 490-bed, tertiary-care university hospital. METHODS: The incidence densities of patients with MRSA and acquisition of mupirocin by the hospital were calculated for the period 1992-2001. S. aureus isolates from 1999-2000 were analyzed by pulsed-field gel electrophoresis. Mupirocin-resistant MRSA isolates from 1994-1995 and 1999-2000 were analyzed for ileS-2 gene background polymorphisms. RESULTS: The incidence density of MRSA patients increased slightly over time, whereas the purchase of mupirocin decreased dramatically. Mupirocin-resistant MRSA infections decreased from 65% in 1994-1995 to 15% in 1999-2000. The MRSA Brazilian clone, detected in 1992, was still highly prevalent. The same ileS-2 encoding plasmid found in 1994-1995 persisted in three identical MRSA isolates from 1999-2000 belonging to the Brazilian clone. CONCLUSIONS: After mupirocin use decreased, the ileS-2 encoding plasmid persisted in only a few Brazilian clone isolates. Our data on mupirocin-resistant MRSA incidence and mupirocin use strongly suggested that restricted use was related to decreased rates of mupirocin resistance at our hospital.