The population structure of 71 carbapenem-resistant Acinetobacter baumannii clinical isolates from several hospitals in Brazil was investigated by ApaI pulsed-field gel electrophoresis, bla OXA-51 -like subtyping, and multilocus sequence typing (Institute Pasteur scheme). In addition to the predominance of strains carrying bla OXA-23 , we detected the presence of bla OXA-72 and bla OXA-231 . We observed a predominance of clonal complex 1 (CC1), CC15, and CC79 and representative strains of the worldwide-disseminated international clone I. The epidemiology of carbapenem-resistant Acinetobacter baumannii (CRAB) strains indicates the predominance of major lineages around the world (1), reinforcing the need to monitor their spread. We evaluated the population structure of CRAB strains circulating in different hospitals in Brazil.Seventy-one CRAB strains, recovered from clinical specimens of nonrepetitive patients who attended 1 of 64 different health institutions located in 23 different cities across the state of São Paulo, Brazil, and were referred to Instituto Adolfo Lutz (a public health laboratory), were studied. Each strain was definitively identified as A. baumannii species (2), and resistances to imipenem and meropenem (Sigma-Aldrich, St. Louis, MO) were confirmed by the broth microdilution technique (3); the MIC 50 and MIC 90 were 16 and 32 g/ml, respectively, for both drugs. bla OXA group genes were detected by multiplex PCR (4, 5) and fully sequenced (6-8). The bla OXA-23 gene was detected in 68 strains (95.8%), and all of them were associated with ISAba1 upstream (9). The frequencies of bla and bla OXA-231 were 2.8% (two strains) and 1.4% (one strain), respectively; none of them were associated with upstream ISAba1. The bla OXA-58 -like gene was not detected. The bla KPC , bla NDM , bla SPM , bla VIM , and bla OXA-48 genes (10) were also not detected. Sequencing of the bla OXA-51 -like gene (11) revealed the predominance of the bla OXA-51 allele in 23 strains (32.4%), of bla OXA-69 in 21 strains (29.6%), and of bla OXA-65 in 21 strains (29.6%); three strains (4.2%) presented the bla OXA-64 allele, two (4.2%) presented the bla OXA-70 allele, and only one (1.4%) presented the bla OXA-88 variant. Pulsed-field gel electrophoresis (PFGE) (12) revealed the occurrence of 64 restriction profiles that were grouped into seven clusters (A to G) on the basis of a 70% cutoff. Multilocus sequence typing (MLST; Institute Pasteur scheme [see http://pubmlst.org/abaumannii/]) and the eBURST algorithm (http://eburst.mlst.net/) identified the predominance of three major clonal complexes (CC1, CC15, and CC79) comprising more than 90% (Table 1) of the CRAB strains circulating in different hospitals across the state of São Paulo in recent years. Considering that CC1, CC15, and CC79 in isolates of OXA-23-producing A. baumannii strains circulating in other regions of Brazil have already been described (14-18), we found evidence for the role of a limited number of clonal complexes of CRAB circulating in this subcontinental country...

Dissemination of carbapenem-resistant Acinetobacter baumannii is currently one of the priority themes discussed around the world, including in Brazil, where this pathogen is considered endemic. A total of 107 carbapenem-resistant A. baumannii (CRAB) isolates were collected from patients with bacteraemia attended at a teaching hospital in Brazil from 2008 to 2014. From these samples, 104 (97.2%) carried blaOXA−23−like, all of them associated with ISAba1 The blaOXA−231 (1.9%) and blaOXA−72 (0.9%) genes were also detected in low frequencies. All isolates were susceptible to minocycline, and 38.3% of isolates presented intermediate susceptibility to tigecycline (MIC = 4 μg/ml). Molecular typing assessed by multi-locus sequence typing demonstrated that the strains were mainly associated with clonal complexes CC79 (47.4%), followed by CC1 (16.9%), and CC317 (18.6%), belonging to different pulsotypes and in different prevalences over the years. Changes in the clones' prevalence reinforce the need of identifying and controlling CRAB in hospital settings to preserve the already scarce therapeutic options available.

Acinetobacter baumannii is a leading cause of complicated infections in the hospital environment, particularly among severely ill patients [1]. The crude mortality attributed to Acinetobacter species causing bloodstream infections is higher than 50 % [2]. Carbapenems have been one of the main antimicrobial classes used against A. baumannii infections [3], but the emergence and dissemination of carbapenemases have diminished the utility of this class of drugs from an already limited list of existing treatment options [4]. In Brazil, it is known that carbapenem-resistant A. baumannii is considered endemic [5], and the main lineages circulating in that country are those belonging to the clonal complexes (CCs) CC1, CC15 and CC79 [6,7]. Among the alternatives for the treatment of infections due to carbapenem-resistant A. baumannii, polymyxins and other non-blactam agents, such as tetracyclines, may be valuable options [3]. Given the increasing rates of multidrug-(MDR) and extensively drug-resistant (XDR) A. baumannii [8], determination of the antimicrobial susceptibility of alternative agents is needed to assess the availability of potential therapeutic options. Thus, the aim of this study was to assess the in vitro activity of antimicrobial agents against carbapenemresistant A. baumannii isolates recovered from clinical specimens of patients from several hospitals in the state of São Paulo, Brazil.A total of 71 A. baumannii isolates recovered from clinical specimens of non-duplicate patients attending 64 different health institutions located in 23 different cities across the state of São Paulo, Brazil, referred to the Instituto Adolfo Lutz from 2008 to 2013 were evaluated. The Instituto Adolfo Lutz, a public health laboratory of São Paulo State, Brazil, receives MDR pathogens, as a reference laboratory, from hospitals across the state of São Paulo on an ongoing and voluntary basis for identification and antimicrobial susceptibility testing. Isolates were mostly recovered from blood or vascular catheter (47.9 %), cerebrospinal fluid (21.9 %), tracheal secretion (13.7 %) and urine (12.3 %); remaining sources were bronchoalveolar lavage, peritoneal fluid and unidentified source (1.4 %, each). Species identification was confirmed by sequencing analysis of the 16S-23S rRNA gene spacer region (internal transcribed spacer) [9]. Antimicrobial susceptibility was determined by disc diffusion methodology [10] for amikacin, gentamicin, tobramycin, ciprofloxacin, levofloxacin, piperacillin-tazobactam, ticarcillin-clavulanate, cefotaxime, cefepime, ceftazidime and trimethoprim-sulfamethoxazole. The MIC values were determined for imipenem, meropenem, ampicillin-sulbactam and minocycline (Sigma-Aldrich) using the broth microdilution technique [11]. Polymyxin B and colistin susceptibilities were determined by agar dilution [11]; tigecycline susceptibility was assessed by Etest (bioM erieux) in freshly prepared Mueller-Hinton agar (Oxoid). MIC values that inhibited 50 % (MIC 50 ) and 90 % (MIC 90 ) of the population were calculated, ...

Atypical enteropathogenic Escherichia coli (aEPEC) strains are unable to produce the bundle-forming pilus (BFP), which is responsible for the localized adherence pattern, a characteristic of the pathogenicity of typical EPEC strains. The lack of BFP in aEPEC strains suggests that other fimbrial or non-fimbrial adhesins are involved in their adhesion to the host cells. The aim of this study was to investigate the distribution of major subunit fimbrial genes known to be important adherence factors produced by several E. coli pathotypes in a collection of 72 aEPEC strains. Our results demonstrate that a high percentage (94–100%) of aEPEC strains harbored ecpA, fimA, hcpA, and lpfA fimbrial genes. Other fimbrial genes including pilS, pilV, sfpA, daaC, papA, and sfa were detected at lower frequencies (1–8%). Genes encoding fimbrial subunits, which are characteristic of enteroaggregative E. coli or enterotoxigenic E. coli were not found. No correlation was found between fimbrial gene profiles and adherence phenotypes. Since all aEPEC strains contained ecpA, the major pilin gene of the E. coli common pilus (ECP), a subset of ecpA+ strains was analyzed for transcription of ecpRABCDE and production of ECP upon growth in three different culture conditions at 37°C. Transcription of ecpRABCDE occurred in all conditions; however, ECP production was medium dependent. In all, the data suggest that aEPEC strains are highly heterogeneous in terms of their fimbrial gene profiles. Despite lacking BFP production, other mechanisms of cell adherence exist in aEPEC strains to ensure host colonization, e.g., mediated by other prevalent pili such as ECP. Moreover, the production of ECP by aEPEC strains might be influenced by yet unknown post-transcriptional factors.

Acinetobacter baumannii is the main species of the Acinetobacter genus; however, non-baumannii Acinetobacter (NBA) species causing infections have been described for the past years, as well as antimicrobial resistance. In this study, we describe the occurrence of two multidrug-resistant (MDR) IMP-1-producing Acinetobacter bereziniae isolates recovered from bloodstream infections in different patients but in the same intensive care unit among 134 carbapenem-resistant Acinetobacter screened. Antimicrobial susceptibility testing revealed resistance to carbapenems, extended spectrum, and antipseudomonad cephalosporins, amikacin, and trimethoprim-sulfamethoxazole. Both A. bereziniae isolates shared the same ApaI-pulsed-field gel electrophoresis (PFGE) pattern. Whole-genome sequencing of both isolates revealed that bla IMP-1 was embedded into an In86 Class I integron carrying also sul1, aac(6¢)-31, and aadA genes. A new sequence type (ST1309 Pasteur) was deposited. The virulence genes lpxC and ompA, seen in A. baumannii, were detected in the A. bereziniae strains. Recognition of A. bereziniae causing invasive MDR infection underscores the role of NBA species as human pathogens especially in at-risk patients.