Plasmid-mediated mcr-1 in carbapenem-susceptible Escherichia coli ST156 causing a blood infection: an unnoticeable spread of colistin resistance in Brazil?

OBJECTIVE: We describe an IncX4 pHC891/16mcr plasmid carrying mcr-1 in a colistin-resistant and carbapenem-susceptible E. coli isolate (HC891/16), ST156, which caused a blood infection in a Brazilian patient with gallbladder adenocarcinoma. METHODS: Strain HC891/16 was subjected to whole genome sequencing using the MiSeq Platform (Illumina, Inc., USA). Assembly was performed using Mira and ABACAS. RESULTS: The isolates showed resistance only to ciprofloxacin, ampicillin and cefoxitin, and whole-genome sequencing revealed the presence of aac(6')Ib-cr and blaTEM1. CONCLUSION: Our findings warn of the possible silent dissemination of colistin resistance by carbapenem-susceptible mcr-1 producers, as colistin susceptibility is commonly tested only among carbapenem-resistant isolates.

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

Abstract 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.

Antimicrobial activity of doripenem against Gram-negative pathogens: results from INVITA-A-DORI Brazilian study

In vitro activity of doripenem and comparator antimicrobial agents was evaluated against Gram-negative bacilli recently isolated from Brazilian private hospitals that were enrolled in the INVITA-A-DORI Brazilian Study. A total of 805 unique Gram-negative bacilli were collected from patients hospitalized at 18 medical centers between May/08 and March/09. Each hospital was asked to submit 50 single Gram-negative bacilli isolated from blood, lower respiratory tract or intraabdominal secretions. Bacterial identification was confirmed and antimicrobial susceptibility testing was performed using Clinical Laboratory Standards Institute (CLSI) microdilution method at a central laboratory. CLSI M100-S21 (2011) or US-FDA package insert criteria (tigecycline) was used for interpretation of the antimicrobial susceptibility results. Doripenem was as active as meropenem and more active than imipenem against E. coli and K. pneumoniae isolates. A total of 50.0 percent of Enterobacter spp. isolates were resistant to ceftazidime but 85.7 percent of them were inhibited at doripenem MICs < 1 µg/mL. Polymyxin B was the only agent to show potent activity against Acinetobacter spp. (MIC50/90, < 0.5/1 µg/mL) and P. aeruginosa (MIC50/90, 1/2 µg/mL). Although high rates of imipenem (53.1 percent) and meropenem (44.5 percent) resistance were detected among P. aeruginosa, doripenem showed MIC50 of 16 µg/mL against imipenem-resistant P. aeruginosa and inhibited a greater number of imipenem-resistant P. aeruginosa (10.5 percent) at MIC values of < 4 µg/mL than did meropenem (0.0 percent). In this study, doripenem showed similar in vitro activity to that of meropenem and retained some activity against imipenem-resistant P. aeruginosa isolated from Brazilian medical centers.

Antimicrobial activity of ceftobiprole against Gram-negative and Gram-positive pathogens: results from INVITA-A-CEFTO Brazilian study

Ceftobiprole is a broad-spectrum cephalosporin with potent activity against staphylococci, including those resistant to oxacillin, as well as against most Gram-negative bacilli including Pseudomonas aeruginosa. In this study, the in vitro activity of ceftobiprole and comparator agents was tested against bacterial isolates recently collected from Brazilian private hospitals. A total of 336 unique bacterial isolates were collected from hospitalized patients between February 2008 and August 2009. Each hospital was asked to submit 100 single bacterial isolates responsible for causing blood, lower respiratory tract or skin and soft tissue infections. Bacterial identification was confirmed and antimicrobial susceptibility testing was performed using CLSI microdilution method at a central laboratory. The CLSI M100-S21 (2011) was used for interpretation of the antimicrobial susceptibility results. Among the 336 pathogens collected, 255 (75.9 percent) were Gram-negative bacilli and 81 (24.1 percent) were Gram-positive cocci. Although ceftobiprole MIC50 values for oxacillin resistant strains were two-fold higher than for methicillin susceptible S. aureus, ceftobiprole inhibited 100 percent of tested S. aureus at MICs < 4 µg/mL. Polymyxin B was the only agent to show potent activity against Acinetobacter spp. (MIC50/90, 0.5/1 µg/mL), and P. aeruginosa (MIC50/90, 1/2 µg/mL). Resistance to broad-spectrum cephalosporins varied from 55.3-68.5 percent and 14.3-28.5 percent among E. coli and Klebsiella spp. isolates, respectively; with ceftobiprole MIC50 > 6 µg/mL for both species. Our results showed that ceftobiprole has potent activity against staphylococci and E. faecalis, which was superior to that of vancomycin. Our data also indicates that ceftobiprole demonstrated potency comparable to that of cefepime and ceftazidime against key Gram-negative species.

Clinical and microbiological characterization of KPC-producing Klebsiella pneumoniae infections in Brazil

In 2008 isolates of KPC-producing Klebsiella pneumoniae (KPC-KPN) were detected for the first time at Hospital Heliópolis, São Paulo, Brazil. The aim of this study was to characterize the clinical and microbiological outcomes of infections caused by KPC-KPN. A historical cohort of patients from whom KPC-KPN strains were isolated was performed. Isolates were identified as resistant to ertapenem by automated broth microdilution system and screened as carbapenemase producers by the modified Hodge test. The beta-lactamase resistance gene blaKPC was detected by PCR. The genetic relatedness of isolates was determined by PFGE. The study provides early clinical experience in treating KPC-KPN infections in a Brazilian tertiary center.

Análise microbiológica de pontas de cateteres venosos centrais provenientes de pacientes internados no Hospital Universitário da Universidade Estadual de Londrina / Microbiological analysis of the central venous catheter tips from hospitalized patients at Hospital Universitário of Universidade Estadual de Londrina

Cateteres venosos centrais (CVC) são utilizados na terapia intravenosa com a finalidade de facilitar o diagnóstico e o tratamento do paciente, pois permitem a administração de edicamentos, nutrição parenteral, além de serem usados como acesso vascular para hemodiálise. Entretanto, o uso desses cateteres oferece riscos de infecção local e sistêmica, incluindo endocardite e bacteremia. O presente estudo teve por objetivo isolar microrganismos de CVC, utilizando a técnica de cultura semi-quantitativa,e identificar os mesmos, mediante provas bioquímicas convencionais e por sistema automatizado. Neste estudo, 198 pontas de CVC foram avaliadas e 105 (53%) foram consideradas positivas, ou seja, apresentaram crescimento microbiano ³ 15 UFC. Os microrganismos encontrados foram os seguintes:63,8% de bactérias Gram-positivas; 30,5% de bactérias Gram-negativas e 5,7% de leveduras. Os microrganismos predominantes foram: Staphylococci coagulase-negativa (35,2%), Staphylococcus aureus (25,7%), Klebsiella pneumoniae (8,5%), Pseudomonas aeruginosa (7,6%), Acinetobacter baumannii (7,6%) e Candida albicans (4,7%). O aumento da incidência de infecção relacionada a cateter tem sido observado mundialmente, e decorre do aumento de procedimentos médicos invasivos, utilizados para o tratamento de pacientes. Este estudo possibilitou identificar os microrganismos predominantes em pontas de CVC, em um hospital escola da região de Londrina-PR. A identificação destes microrganismos é de extrema importância para otimizar o tratamento da infecção e estabelecer medidas preventivas.

Microbiologia convencional, ELISA e PCR para detecção de Salmonella em abatedouro de frango totalmente automatizado, semi-automatizado de grande porte e semi-automatizado de pequeno porte / Conventional microbiology, ELISA and PCR for detention of Salmonella in abattoirs of chicken total automatized, half-automatized of great half-automatized and of small transport

O presente estudo teve como objetivo realizar uma análise comparativa das técnicas de Reação em Cadeia por Polimerase (PCR) e Ensaio Imunoenzimático (ELISA – SALVIA), com o método microbiológico convencional, para detecção de Salmonella em três categorias de abatedouros: um com abate totalmente automatizado (ATA) e dois com abate semi-automatizado, sendo um de grande porte (ASAGP) e outro de pequeno porte (ASAPP). Foram coletadas amostras de 20 lotes, distribuídos em 20 pools de suabes cloacais de 100 aves, 20 carcaças de frango após a evisceração e antes do chiller e 20 carcaças de frango após o chiller, totalizando 60 lotes e 180 amostras. Os resultados mostraram que na microbiologia convencional (MC) foram isoladas 47/180 amostras positivas (26 por cento), ELISA 32/180 (17,8 por cento) e PCR 22/180 (12,2 por cento). Houve diferença estatística significativa entre as três técnicas, sendo que a MC apresentou eficácia superior (p=0,05) na detecção de Salmonella em relação às demais técnicas. Foi também investigada a presença de Salmonella em diferentes etapas do processamento industrial das três categorias de matadouro avícola. No abatedouro ATA foram identificadas 30/60 (50 por cento) amostras positivas para Salmonella, sendo 12/20 (60 por cento) no suabe cloacal, 14/20 (70 por cento) antes de chiller e 4/20 (20 por cento) após o chiller. No abatedouro ATAGP, 4/20 (20 por cento) amostras foram positivas no suabe cloacal, 5/20 (25 por cento) antes do chiller e 8/20 (40 por cento) após o chiller, totalizando 17/60 (28,3 por cento) amostras positivas, enquanto que no abatedouro ASAPP não houve isolamento de Salmonella.