Pathogenesis and toxins Clostridium difficile infection among immunocompromised patients in Rio de Janeiro, Brazil and detection of moxifloxacin resistance in a ribotype 014 strain Danielle Angst Secco a, * , Ilana Teruszkin Balassiano b , Renata Ferreira Boente a , Karla Rodrigues Miranda a , Jon Brazier c , Val Hall c , Joaquim dos Santos-Filho a , Leandro Araujo Lobo a , Simone Aranha Nou  er d , Regina Maria Cavalcanti Pilotto Domingues a a Laborat orio de Biologia de Anaer obios, Departamento de Microbiologia M edica, Instituto de Microbiologia Prof. Paulo de G oes, Centro de Ci^ encias da Saúde, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, CEP 21941-900 Rio de Janeiro, RJ, Brazil b Laborat orio de Zoonoses Bacterianas, Instituto Oswaldo Cruz-Fiocruz, Rio de Janeiro, RJ, Brazil c Anaerobe Reference Unit, Public Health Wales Microbiology, University Hospital of Wales, Cardiff, Wales, United Kingdom d Coordenaç~ ao de Controle de Infecç~ oes Hospitalares - HUCCF/UFRJ, Rio de Janeiro, RJ, Brazil article info Article history: Received 11 February 2014 Received in revised form 21 May 2014 Accepted 25 May 2014 Available online 5 June 2014 Keywords: Clostridium difficile CDI Nosocomial infection Moxifloxacin resistance abstract Clostridium difficile is a Gram-positive spore forming anaerobic bacterium, often associated with noso- comial diarrhea and pseudomembranous colitis. The acquisition of this organism occurs primarily in hospitals through accidental ingestion of spores, and its establishment and proliferation in the colon results from the removal of members of the normal intestinal flora during or after antibiotic therapy. In this study, stool samples from patients admitted to the University Hospital Clementino Fraga Filho (HUCCF/UFRJ) were screened for C. difficile toxins with an ELISA test and cultured with standard tech- niques for C. difficile isolation. A total of 74 stool samples were collected from patients undergoing antibiotic therapy between August 2009 and November 2010, only two (2.7%) were positive in the ELISA test and culture. A third isolate was obtained from a negative ELISA test sample. All cases of CDI were identified in patients with acute lymphoid or myeloid leukemia. Genotypic and phenotypic character- ization showed that all strains carried toxins A and B genes, and belonged to PCR-ribotypes 014, 043 and 046. The isolated strains were sensitive to metronidazole and vancomycin, and resistant to ciprofloxacin and levofloxacin. Resistance to moxifloxacin, was present in the strain from PCR-ribotype 014, that showed an amino acid substitution in gyrB gene (Asp 426 / Asn). This is the first time that this mutation in a PCR-ribotype 014 strain has been described in Brazil. © 2014 Elsevier Ltd. All rights reserved. 1. Introduction Clostridium difficile is a Gram-positive spore forming anaerobic bacterium. C. difficile infection (CDI) is highly prevalent in hospitals and is the most common cause of nosocomial diarrhea in adults, mainly in elderly and immunocompromised patients [1,2]. CDI cases in solid organ transplant recipients, hematopoietic stem cell or bone marrow transplant recipients and HIV-seropositive in- dividuals are reported to be higher in units caring for these patients [3]. Proliferation of C. difficile in the colon results from the removal of members of the normal intestinal flora in consequence of anti- biotic therapy [4,5]. Practically any antibiotic can be associated with CDI, but the antibiotics most commonly associated are clindamycin, cephalosporins and penicillins [6,7]. However, many studies have also described a high association between fluoroquinolones use and CDI, that may be related, even in part, to the development of fluoroquinolones resistance among C. difficile isolates in the last years [8e12]. C. difficile pathogenic strains are able to produce two toxins, enterotoxin A (TcdA) and cytotoxin B (TcdB), which constitute the major virulence factors of this species [7]. These toxins elicit several effects on the host, such as chemokine and cytokine production, * Corresponding author. Tel.: þ55 21 2560 8344. E-mail address: daniangstsecco@gmail.com (D.A. Secco). Contents lists available at ScienceDirect Anaerobe journal homepage: www.elsevier.com/locate/anaerobe http://dx.doi.org/10.1016/j.anaerobe.2014.05.013 1075-9964/© 2014 Elsevier Ltd. All rights reserved. Anaerobe 28 (2014) 85e89