Adriana Pereira Matos

Nosocomial infections with metallo-beta-lactamase-producing Pseudomonas aeruginosa: molecular epidemiology, risk factors, clinical features and outcomes.

BACKGROUND Metallo-β-lactamases (MBLs) have emerged as one of the most important bacterial resistance mechanisms because of their ability to hydrolyse virtually all β-lactam agents. MBL-producing Pseudomonas aeruginosa (MBL-PA) are an important cause of nosocomial infections, particularly in intensive care units (ICUs), where they are associated with serious infections and present a significant clinical risk. AIM To assess the molecular epidemiology, risk factors and outcomes of nosocomial infections caused by MBL-PA in a teaching hospital in Southern Brazil. METHODS From January 2001 to December 2008, 142 carbapenem-resistant P. aeruginosa strains were isolated from distinct clinical samples from hospitalized patients. These isolates were screened for MBLs, and underwent polymerase chain reaction, sequencing and pulsed-field gel electrophoresis (PFGE). Patients infected with carbapenem-resistant MBL-PA were considered as cases, and patients infected with non-MBL-PA were considered as controls. FINDINGS Eighty-four of 142 patients with positive carbapenem-resistant P. aeruginosa cultures met the criteria of the Centers for Disease Control and Prevention for infection. Fifty-eight patients were infected with MBL-PA (69%) and 26 patients were infected with non-MBL-PA (31%). Multi-variate analysis revealed that ICU stay [P = 0.003, odds ratio (OR) 4.01, 95% confidence interval (CI) 1.15-14.01] and urinary tract infection (P = 0.001, OR 9.67, 95% CI 1.72-54.48) were important risk factors for MBL-PA infection. Patients infected with MBL-PA showed faster onset of infection (P = 0.002) and faster progression to death (P = 0.04). CONCLUSIONS These results showed the severity of MBL-PA infections, and demonstrated the urgent need for strategies to improve infection control measures to prevent an increase in these nosocomial infections.

Identification of a New Integron Harboring blaIMP-10 in Carbapenem-Resistant Acinetobacter baumannii Clinical Isolates

We describe herein the characterization of a novel class 1 integron harboring the bla IMP-10 gene in Acinetobacter baumannii clinical isolates.…

Old Clinical Isolates of Acinetobacter seifertii in Brazil Producing OXA-58

The genus Acinetobacter comprises several groups of closely related species, including the Acinetobacter calcoaceticus-Acinetobacter baumannii complex ([1][1]) and a number of hemolytic species ([2][2]). Currently, the A. calcoaceticus-A. baumannii complex comprises five validly named species,

Serratia marcescens harboring SME-4 in Brazil: A silent threat

The intrinsic polymyxin resistance displayed by Serratia marcescens makes the acquisition of carbapenemase encoding genes a worrisome event. This study report a SME-4-producing S. marcescens isolate causing septic shock in Brazil. The insertion of novel resistance determinants and their consequent spread in our territory is noteworthy.

Comparison of phenotypic tests for the detection of metallo-beta-lactamases in clinical isolates of Pseudomonas aeruginosa

Metallo-β-lactamase (MBL)-producing gram-negative bacteria are an increasing public health concern worldwide. Screening tests for the rapid and specific identification of these pathogens are essential, and should be included among routine diagnostics in laboratories. This study aimed to determine the MBL frequency among carbapenem-resistant Pseudomonas aeruginosa isolates, and to evaluate the accuracy of different tests in screening for MBL production. From January 2001 to December 2008, a total of 142 imipenem-non-susceptible P. aeruginosa strains were isolated from distinct clinical samples from hospitalized patients. These isolates were examined by PCR, MBL E-test, double-disk synergy test (DDST), and combined disk (CD) test. The minimal inhibitory concentration (MIC; μg/mL) was determined by agar dilution, and pulsed field gel electrophoresis (PFGE) was performed on all samples. Sequencing was performed to confirm and define the MBL variant and subtype. Using PCR and DNA sequence analysis, 93 strains were confirmed positive for MBLs, 91 strains for the blaSPM-1 gene, 1 strain for the blaIMP-1 gene, and 1 strain for the blaIMP-16 gene. PFGE displayed a clonal pattern. The sensitivities, specificities, positive and negative predictive values were evaluated for all tests. The DDST assay (CAZ-MPA) was the optimal method for screening MBL production in P. aeruginosa strains. However, the results of the CD assay (IMP/EDTA) showed close agreement with those of the DDST. In addition, the CD assay allowed a more objective interpretation and did not require the use of a toxic substance.

Temporal evolution of polymyxin B-resistant Klebsiella pneumoniae clones recovered from blood cultures in a teaching hospital during a 7-year period

The polymyxins have become one of the last resorts to treat serious infections caused by KPC-2-producing Klebsiella pneumoniae worldwide. However, the increase of polymyxin consumption has favored the emergence of resistance to these compounds. In this study, we observed an increase in polymyxin B resistance rates from 0 to 30.6% among 224 K. pneumoniae isolates recovered from blood cultures between 2009 and 2015. Only gentamicin, tigecycline and fosfomycin remained active against the polymyxin B-resistant K. pneumoniae (PMB-R-KPN) isolates, which were classified as extensively drug-resistant (XDR; 83.3%), multidrug-resistant (MDR; 13.9%), or pan-drug resistant (2.8%). Most PMB-R-KPN clones belonged to CC258 (ST11, ST258, ST340, and ST437). A C7/ST258 XDR clone carrying distinct resistance determinants (blaSHV-11, blaTEM-1, blaCTX-M-15, blaCTX-M-14, blaKPC-2, and rmtB-1) was introduced in 2014. Twelve of 36 PMB-R-KPN isolates showed disruption of mgrB. No mcr-1-positive isolate was found. The rapid detection of PMB-R-KPN isolates allied to implementation of effective infection control measures are of crucial importance to avoid the dissemination of high-risk PMB-R-KPN clones.

Detection of blaVIM-7 in an extensively drug-resistant Pseudomonas aeruginosa isolate belonging to ST1284 in Brazil

We described for the first time an extensively drug-resistant Pseudomonas aeruginosa isolate belonging to ST1284 carrying a plasmid-mediated blaVIM-7 in Brazil. The blaVIM-7 was harbored by an integron that also carried aacA4 and blaOXA-46. Multiple virulence factors were also detected.

Detection of OXA-58-Producing Acinetobacter seifertii Recovered from a Black-Necked Swan at a Zoo Lake

Ana Clara Narciso,a Willames M. B. S. Martins,a Rodrigo Cayô,a Adriana Pereira de Matos,a Stéfanie Vanessa Santos,a Patrícia Locosque Ramos,b João Batista da Cruz,c Ana Cristina Galesa Universidade Federal de São Paulo UNIFESP, Laboratório Alerta, Division of Infectious Diseases, Department of Internal Medicine, Escola Paulista de Medicina EPM, São Paulo, SP, Brazila; Departamento de Pesquisas Aplicadas, Fundação Parque Zoológico de São Paulo, São Paulo, Brazilb; Fundação Parque Zoológico de São Paulo—FPZSP, São Paulo, Brazilc

Occurrence of IMP-1 in non-baumannii Acinetobacter clinical isolates from Brazil

The aim of this study was to characterize the presence of carbapenemase-encoding genes in distinct species of Acinetobacter spp. isolated from Brazilian hospitals. Five carbapenem-resistant Acinetobacter spp. isolates (two Acinetobacter pittii, two Acinetobacter bereziniae and one Acinetobacter junii) recovered from two distinct hospitals between 2000 and 2016 were included in this study. All of the isolates harboured blaIMP-1, which was inserted into In86, a class 1 integron. Pulsed field gel eletrophoresis analysis showed that both A. pittii were identical, while the two A. berezinae isolates were considered to be clonally related. In this study, we demonstrated that mobile elements carrying carbapenemase-encoding genes such as In86 may persist for a long period, allowing their mobilization from A. baumannii to other Acinetobacter spp. that are usually susceptible to multiple antimicrobials.