João Nobrega de Almeida

Carbapenem stewardship: positive impact on hospital ecology

INTRODUCTION Excessive group 2 carbapenem use may result in decreased bacterial susceptibility. OBJECTIVE We evaluated the impact of a carbapenem stewardship program, restricting imipenem and meropenem use. METHODS Ertapenem was mandated for ESBL-producing Enterobacteriaceae infections in the absence of non-fermenting Gram-negative bacilli (GNB) from April 2006 to March 2008. Group 2 carbapenems were restricted for use against GNB infections susceptible only to carbapenems and suspected GNB infections in unstable patients. Cumulative susceptibility tests were done for nosocomial pathogens before and after restriction using Clinical and Laboratory Standards Institute (CLSI) guide-lines.Vitek System or conventional identification methods were performed and susceptibility testing done by disk diffusion according to CLSI.Antibiotic consumption (t-test) and susceptibilities (McNemars test) were determined. RESULTS The defined daily doses (DDD) of group 2 carbapenems declined from 61.1 to 48.7 DDD/1,000 patient-days two years after ertapenem introduction (p = 0.027). Mean ertapenem consumption after restriction was 31.5 DDD/1,000 patient-days. Following ertapenem introduction no significant susceptibility changes were noticed among Gram-positive cocci. The most prevalent GNB were P. aeruginosa, Klebsiella pneumoniae, and Acinetobacter spp. There was no change in P. aeruginosa susceptibility to carbapenems. Significantly improved P. aeruginosa and K. pneumoniae ciprofloxacin susceptibilities were observed, perhaps due to decreased group 2 carbapenem use. K. pneumoniae susceptibility to trimethoprim-sulfamethoxazole improved. CONCLUSION Preferential use of ertapenem resulted in reduced group 2 carbapenem use, with a positive impact on P. aeruginosa and K. pneumoniae susceptibility.

First report of a clinical isolate of Candida haemulonii in Brazil

The spectrum of Candida species associated with invasive fungal infections is evolving. New microbiology diagnostic tools, the increasing number of immunosuppressed patients with invasive devices and the use of prophylaxis with fluconazole could contribute to this phenomenon (1). In recent years, an increasing number of rare species with reduced susceptibility to antifungal molecules have been described, including C. ciferrii, C. inconspicua, C. guilliermondii, C. humicola, C. lambica, C. lipolytica, C. norvegensis, C. palmioleophila, C. rugosa, C. valida, C. fermentati, and C. lusitaniae (2)-(5). Data from the SENTRY Antimicrobial Surveillance Program-Fungal Objective (5) concerning bloodstream infections from 2008 and 2009 show that 4.5% of 348 episodes from 10 centers in Latin America were caused by species other than C. albicans, C. glabrata, C. parapsilosis, C. tropicalis, and C. krusei. In 1984, Lavarde et al. (6) reported the first clinical isolate of C. haemulonii from a blood culture. Since then, rare cases of human infections with C. haemulonii have been reported worldwide, including central venous catheter (CVC)-related bloodstream infections in patients from Argentina, Korea, and China (7)-(11); in preterm neonates receiving parenteral nutrition in Kuwait (12); and in a 37-year-old French patient with osteomyelitis of the left hallux (13). This pathogen has not been identified in previous reports of candidemia from Brazil (14)-(17). The present paper reports for the first time a case of fungemia caused by C. haemulonii in a tertiary hospital in the city of Sao Paulo. Clinical features and laboratory analyses, including phenotypic and molecular identification and antifungal susceptibility testing (AST), are described.

Emergence of colistin resistance in the largest university hospital complex of São Paulo, Brazil, over five years

Colistin resistance involving Gram-negative bacilli infections is a challenge for health institutions around of the world. Carbapenem-resistance among these isolates makes colistin the last therapeutic option for this treatment. Colistin resistance among Enterobacteriaceae, Acinetobacter spp., and Pseudomonas spp. was evaluated between 2010 and 2014 years, at Hospital das Clínicas, São Paulo, Brazil. Over five years 1346 (4.0%) colistin resistant Gram-negative bacilli were evaluated. Enterobacteriaceae was the most frequent (86.1%) pathogen isolated, followed by Acinetobacter spp. (7.6%), and Pseudomonas spp. (6.3%). By temporal analysis there was a trend for an increase of colistin resistance among Enterobacteriaceae, but not among non-fermentative isolates. Among 1346 colistin resistant isolates, carbapenem susceptibility was observed in 21.5%. Colistin resistance in our hospital has been alarmingly increased among Klebsiella pneumoniae isolates in both KPC positive and negative, thus becoming a therapeutic problem.

Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Differentiation of the Dimorphic Fungal Species Paracoccidioides brasiliensis and Paracoccidioides lutzii

ABSTRACT Isolates of Paracoccidioides brasiliensis and Paracoccidioides lutzii, previously characterized by molecular techniques, were identified for the first time by matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS). All isolates were correctly identified, with log score values of >2.0. Thus, MALDI-TOF MS is a new tool for differentiating species of the genus Paracoccidioides.

Evaluation of the MALDI-TOF VITEK MS™ system for the identification of Candida parapsilosis, C. orthopsilosis and C. metapsilosis from bloodstream infections

Twenty-nine Candida parapsilosis, seventeen Candida orthopsilosis and two Candida metapsilosis bloodstream isolates were submitted for identification by VITEK-MS™ mass spectrometer. Four isolates, two C. orthopsilosis and two C. metapsilosis, were not identified. Inclusion of Superspectra of both species in this database is required to improve its discrimination power.

Evaluation of VITEK 2 for discriminating Trichosporon species: misidentification of Trichosporon non–T. asahii

The VITEK 2 system was evaluated for the identification of 74 Trichosporon invasive and non-invasive clinical isolates, comparing its results with the IGS1 sequencing. The system correctly identified Trichosporon asahii but not non-T. asahii isolates, which represented nearly 50% of the invasive infections in our nosocomial setting.

Candida blankii : an emergent opportunistic yeast with reduced susceptibility to antifungals

In 1968, Buckley and van Uden described the nonfermenting yeast Candida blankii (C. blankii) found in the organs of a mink. Until recently, this microorganism had only been the subject of biotechnological research. However, in 2015, Zaragoza et al. reported a 14-year-old male patient with cystic fibrosis (CF), who had pulmonary exacerbations with repeated isolation of C. blankii from respiratory samples. This finding raised the hypothesis that this yeast could be a relevant pathogen for CF patients.This paper corroborates this initial observation by describing a bloodstream infection by C. blankii in a CF patient who underwent lung transplantation. A 16-year-old female with CF was referred to our lung transplant center in March 2016. Her recent medical history was notable for severe pulmonary exacerbations, which required prolonged hospitalization and mechanical ventilation. Her most recent preadmission sputum cultures collected by the referring hospital showed positive for Staphylococcus aureus, Pseudomonas aeruginosa, Burkholderia cepacia, Aspergillus sp., including positive samples for Candida sp. (negative germ tube, isolates not available) collected after itraconazole therapy (200 mg/day) used to treat the pulmonary exacerbations. In June 2016, she underwent bilateral lung transplantation at the Hospital das Clínicas, University of São Paulo, Brazil, under antimicrobial prophylaxis consisting of teicoplanin, meropenem, cotrimoxazole and liposomal amphotericin B (L-AMB, 200 mg/day). However, during the infusion of L-AMB, the patient presented hypotension, leading to the discontinuation of the antifungal treatment. On the first postoperative day (POD), the patient developed sepsis, and so blood cultures were collected (Bactec aerobic and anaerobic/Plus, BD). Peripheral and central venous catheter blood cultures became positive for yeasts after 41 (anaerobic bottle) and 72 (aerobic bottles) hours of incubation, respectively. On the third POD, due to the provisional report of yeasts on blood cultures, micafungin (100 mg/day) was prescribed. Blood cultures collected 72 h after the introduction of micafungin became negative; transthoracic echocardiography and fundoscopic eye exam did not show any significant results. The yeast isolate showing pale pink colonies on chromogenic medium (BBL CHROMagar, BD, Sparks, USA) were not identified by MALDI-TOF mass spectrometry (Vitek MSTM, IVD library, bioMérieux, Marcy-L ́Etoile, France). Because clinical improvement was observed, micafungin was maintained for 14 days. The patient was discharged on the 39th POD. The clinical isolate (HCFMUSP01) was later identified as C. blankii after sequence analysis of the internal transcribed spacer 1 (ITS1, GenBank accession no. MF573785) and D1D2 region from the 26S subunit (D1D2, GenBank accession no. MF940140) of the rRNA. Since little is known about this microorganism as an opportunistic pathogen, we further characterized this species in terms of genetic and proteomic diversity, antifungal susceptibility, biofilm production, and in vivo virulence by analyzing the clinical isolate and the strains (IIC1M.1, BX90C, BX81A) from the yeast collection at the Federal University of Minas Gerais, Brazil.

Lomentospora prolificans fungemia in hematopoietic stem cell transplant patients: First report in South America and literature review

Lomentospora prolificans is a filamentous fungus and an emerging pathogen in immunocompromised patients. It is encountered most commonly in Australia, Spain, and USA. We described the first case of Lomentospora prolificans fungemia in South America. The patient was a hematopoietic stem cell transplantation (HSCT) recipient who developed the infection 37 days after stem cells infusion. In addition, we performed a literature review of invasive lomentosporiosis in HSCT patients.

Colistin susceptibility testing and Vitek-2 (TM): is it really useless?

In this study we evaluated the performance of Vitek-2TM (bioMérieux, MarcyL’Etoile, France) on determination of colistin susceptibility in comparison with gold standard broth microdilution method. The Vitek-2 showed 90.1% of essential agreement (EA) and 91.4% categorial agreement (CA), for Enterobacteriaceae isolates. In addition, 0.7% of major errors (ME) and 7.94% of very major errors (VME) was observed. However, K. pneumoniae and E. coli, the Vitek-2 showed better performance for isolates with ≤ 0.5 or ≥ 16 μg/mL MICs. For P. aeruginosa isolates, colistin resistant isolates must be confirmed. For Acinetobacter spp. and Enterobacter spp., all colistin MICs should be confirmed and attention for borderline MICs (2 to 8 μg/mL) should be taken, confirming with a reference method for all specie. ACCEPTED MANUSCRIPT

Emergence of Trichosporon mycotoxinivorans (Apiotrichum mycotoxinivorans) invasive infections in Latin America

We report the first two cases of Trichosporon mycotoxinivorans infections in Latin America. We also conducted a literature review and a microbiological investigation, including that of clinical and environmental isolates. A 30-year-old man with chronic renal failure had disseminated infection after dialysis and a 15-year-old boy with cystic fibrosis (CF) had pulmonary exacerbations with positive respiratory samples. A review of the relevant literature revealed that deep-seated infections were related to immunosuppression or invasive devices, while most of the CF patients showed a decline in lung function after positive cultures. Phylogenetic analyses revealed three distinct circulating genotypes. MALDI-TOF mass spectrometry analysis showed similar spectral profiles and correctly identified all strains/isolates. Biofilm production was documented in a bloodstream isolate and biofilm-producing cells showed high minimum inhibitory concentrations against antifungals.