Dissemination of NDM-producing bacteria in Southern Brazil.

BACKGROUND: The dissemination of NDM-1 carbapenemases (New Delhi Metallo-ß-lactamase) is a global public health problem, mainly in developing countries. The aim of this study was to characterize the spread of NDM-producing bacteria in the Southern Brazilian states analyzing epidemiological, molecular, and antimicrobial susceptibility aspects. METHODS: A total of 10,684 carbapenem-resistant isolates of Enterobacterales, Pseudomonas spp. and Acinetobacter spp. obtained from several hospitals in eight cities in Southern Brazil were screened, and 486 NDM-producing bacteria were selected. RESULTS: The incidence varied from 0.5 to 77 cases/100.000 habitants. ST11, ST15, ST340 and ST674 were the most common in K. pneumoniae. A total of 5 plasmids were identified in one K. pneumoniae strain: Col440I, Col440II, IncFIA(HI1), IncFIB(K), IncFIB(pQil)/ IncFII(K), and IncR. CONCLUSIONS: The number of patients with NDM-producing bacteria has increased in Southern Brazil, whose gene is present in different plasmids, explaining the expansion of this enzyme.

Resolving taxonomic confusion: establishing the genus Phytobacter on the list of clinically relevant Enterobacteriaceae.

Although many clinically significant strains belonging to the family Enterobacteriaceae fall into a restricted number of genera and species, there is still a substantial number of isolates that elude this classification and for which proper identification remains challenging. With the current improvements in the field of genomics, it is not only possible to generate high-quality data to accurately identify individual nosocomial isolates at the species level and understand their pathogenic potential but also to analyse retrospectively the genome sequence databases to identify past recurrences of a specific organism, particularly those originally published under an incorrect or outdated taxonomy. We propose a general use of this approach to classify further clinically relevant taxa, i.e., Phytobacter spp., that have so far gone unrecognised due to unsatisfactory identification procedures in clinical diagnostics. Here, we present a genomics and literature-based approach to establish the importance of the genus Phytobacter as a clinically relevant member of the Enterobacteriaceae family.

Low level of polymyxin resistance among nonclonal mcr-1-positive Escherichia coli from human sources in Brazil.

We report 26 human isolates of mcr-1-positive Escherichia coli, most of them (65.4%) with a polymyxin B MIC of 2 mg/L. Seventeen out of the 24 mcr-1-positive E. coli proved to be nonclonal by rep-PCR which strengthens the hypothesis of environmental or animal origin of these strains and reinforces the one health context of antimicrobial resistance.

Emended description of the genus Phytobacter, its type species Phytobacter diazotrophicus (Zhang 2008) and description of Phytobacter ursingii sp. nov.

The species Phytobacter diazotrophicus and the associated genus Phytobacter were originally described by Zhanget al. [Arch Microbiol189 (2008), 431-439] on the basis of few endophytic nitrogen-fixing bacteria isolated from wild rice (Oryza rufipogon) in China. In this study, we demonstrate that a number of clinical isolates that were either described in the literature, preserved in culture collections, or obtained during a 2013 multi-state sepsis outbreak in Brazil also belong to the same genus. 16S rRNA gene sequencing, multilocus sequence analysis based on gyrB, rpoB, atpD and infB genes, as well as digital DNA-DNA hybridization support the existence of a second species within the genus Phytobacter. All isolates from the recent Brazilian outbreak, along with some older American clinical strains, were found to belong to the already described species Phytobacterdiazotrophicus, whereas three clinical strains retrieved in the USA over a time span of almost four decades, could be assigned to a new Phytobacter species. Implementation of an extended set of biochemical tests showed that the two Phytobacter species could phenotypically be discriminated from each other by the ability to utilize l-sorbose and d-serine. This feature was limited to the strains of the novel species described herein, for which the name Phytobacter ursingii sp. nov. is proposed, with ATCC 27989T (=CNCTC 5729T) as the designated type strain. An emended description of the species Phytobacter diazotrophicus and of the genus Phytobacter is also provided.

Risk factors for mortality in patients with ventilator-associated pneumonia caused by carbapenem-resistant Enterobacteriaceae

Abstract Background: The ideal therapeutic option for ventilator associated pneumonia caused by carbapenem-resistant Enterobacteriaceae is not defined. The aim of this study was to assess mortality-associated risk factors in patients with VAP by CRE and determine the outcome of several treatment options. Methods: This was a retrospective study performed in two tertiary hospitals involving patients with VAP caused by CRE between January 2010 and August 2014. The outcomes were mortality within 30 days of VAP diagnosis and overall mortality during hospital admission. Risk factors for mortality were assessed by comparing variables of survivors and non-survivors. Results: One hundred and twelve patients with CRE-VAP were included, 73 (65%) male, median age 56 years. The 30-day mortality was 57.1% and the overall hospital mortality was 67%. In the binary logistic regression analysis, only age >50 years was independently associated to increased mortality. Polymyxin was the most used drug (47.5%), followed by tigecycline (29.2%) and aminoglycosides (2.4%). Combined therapy with two active drugs was used by 17 patients (20.8%). No therapeutic option was independently associated to survival. However, combined therapy with two active drugs was superior to the therapy with a single active drug when inappropriate therapy was the comparator (p = 0.044). The addition of carbapenem was not associated with increased survival. Conclusion: The best therapeutic option for VAP by CRE is still not completely defined, but the therapy with at least two active drugs was superior in this study.

Risk factors for mortality in patients with ventilator-associated pneumonia caused by carbapenem-resistant Enterobacteriaceae.

BACKGROUND: The ideal therapeutic option for ventilator associated pneumonia caused by carbapenem-resistant Enterobacteriaceae is not defined. The aim of this study was to assess mortality-associated risk factors in patients with VAP by CRE and determine the outcome of several treatment options. METHODS: This was a retrospective study performed in two tertiary hospitals involving patients with VAP caused by CRE between January 2010 and August 2014. The outcomes were mortality within 30 days of VAP diagnosis and overall mortality during hospital admission. Risk factors for mortality were assessed by comparing variables of survivors and non-survivors. RESULTS: One hundred and twelve patients with CRE-VAP were included, 73 (65%) male, median age 56 years. The 30-day mortality was 57.1% and the overall hospital mortality was 67%. In the binary logistic regression analysis, only age >50 years was independently associated to increased mortality. Polymyxin was the most used drug (47.5%), followed by tigecycline (29.2%) and aminoglycosides (2.4%). Combined therapy with two active drugs was used by 17 patients (20.8%). No therapeutic option was independently associated to survival. However, combined therapy with two active drugs was superior to the therapy with a single active drug when inappropriate therapy was the comparator (p=0.044). The addition of carbapenem was not associated with increased survival. CONCLUSION: The best therapeutic option for VAP by CRE is still not completely defined, but the therapy with at least two active drugs was superior in this study.

KPC-producing Enterobacter aerogenes infection.

BACKGROUND: Enterobacter is a common nosocomial microorganism and its carbapenem's resistance has increased. The management of these cases is unclear. OBJECTIVE: We evaluated 16 patients with KPC-producing Enterobacter aerogenes infections, detailing the site of infection, therapy, clinical and epidemiological data. METHODS: A retrospective and descriptive study. Clinical data were revised and KPC-2 detection was by molecular methods. Risk factors associated with mortality were compared using appropriate tests according to variable type with a significance level of 0.05. RESULTS: The 30-day mortality rate was 37.5% with no association with inadequate treatment. Age (p=0.004) and Charlson score of comorbidities (p=0.048) were independent risk factors associated with death in the multivariate analysis. The odds ratio for age >43 years was 3.00 (95% CI: 1.02-9.32) and for Charlson score >3 was 2.00 (95% CI: 1.08-3.71). Five strains were pan-resistant based on automated susceptibility tests. All patients were treated with monotherapy. CONCLUSION: The clinician should be alert to carbapenem-resistant Enterobacteriaceae infection in older patients with comorbidities. The mortality is high and we believe that prompt and adequate therapy must be employed.

Phenotypic and molecular characterization of 942 carbapenem-resistant Enterobacteriaceae (CRE) in southern Brazil.

Carbapenem-resistant Enterobacteriaceae (CRE) is a major international health problem, and its identification in developing countries is based exclusively on phenotypic methods. The aim of this study was to assess the sensitivity and related parameters of the modified Hodge test (MHT). The assessment was performed in a large number of isolates obtained from different hospitals in several cities of a south Brazilian state. Bacterial species were identified using an automated method. The MHT was performed according to the guidelines set by the CLSI. The gene blaKPC was amplified in order to confirmation CRE expression. The sensitivity, specificity, positive, and negative predictive values were calculated. A total of 942 isolates were submitted to the reference laboratory for confirmation; 143 showed a negative MHT (15.18%) result, while 784 were positive (83.23%), and 15 samples displayed an indeterminate MHT (1.59%) result. All samples expressed the KPC-2 enzyme. Sensitivity, specificity, positive, and negative predictive percentiles were 99%, 89%, 98%, and 99% respectively. We conclude that the modified Hodge test is a reliable test for the prediction of KPC-producing bacteria.

Molecular epidemiology of Klebsiella pneumoniae carbapenemase-producing Enterobacteriaceae in different facilities in Southern Brazil.

BACKGROUND: Klebsiella pneumoniae carbapenemase-producing K pneumoniae (KPC-KP) outbreaks have been reported in many countries, including Brazil. The incidence of KPC-KP infection has increased in the first semester of 2011 in Curitiba, the capital of Parana, in Southern Brazil.The aim of this study was to characterize the infections and clonal diversity of KPC-KP isolates from several institutions in Curitiba. METHODS: KPC-KP from several clinical samples and rectal swabs taken between April 2010 and July 2012 were included. One isolate per patient was evaluated. All isolates were submitted to polymerase chain reaction (PCR) for blaKPC. The genetic relatedness was evaluated using strain clustering by an automated repetitive extragenic palindromic (rep) PCR-based typing system. RESULTS: There were 641 samples that were positive for K pneumoniae carbapenemase-2 carbapenemase. There were 129 samples randomly selected for clonality evaluation. PCR and strain clustering by the automated rep PCR-based typing system identified 7 clones (A-C and E-H). Clone E was identified in only 1 hospital, and all other clones were found in >2 hospitals. Clones C and G were the most disseminated among hospitals. The infection and colonization occurred in 14 out of the 32 main hospitals in town. Similar clones were found in 2 hospitals that are administered by the same group. Another clone (H) was found in 2 hospitals receiving patients from the same municipal emergency unit. CONCLUSION: The KPC-KP outbreak in Curitiba is polyclonal, and the source is unknown. Some hospitals share the same clones.

Validação do teste de inibição pelo ácido aminofenilborônico para triagem de Klebsiella pneumoniae carbapenemases (KPC) / Validation of inhibition test by aminophenyl boronic acid to Klebsiella pneumoniae carbapenemases (KPC) screening

INTRODUÇÃO: A produção de enzimas Klebsiella pneumoniae carbapenemase (KPC) tem se tornado um importante e preocupante mecanismo de resistência, e ensaios que combinem alta sensibilidade e alta especificidade para a detecção dessas enzimas são escassos. OBJETIVO: Validar o teste de inibição pelo ácido 3-aminofenilborônico como método de triagem fenotípica de cepas produtoras de enzima KPC, comparando os resultados obtidos com os de testes confirmatórios por reação em cadeia da polimerase (PCR). METODOLOGIA: Avaliou-se o uso do ácido 3-aminofenilborônico impregnado em discos de antibióticos de imipenem, meropenem e ertapenem. Foram testadas 36 cepas positivas e 12 negativas, todas confirmadas por PCR. Foram ainda testadas três concentrações diferentes de ácido borônico: 300, 400 e 600 µg. RESULTADOS: Entre as cepas positivas testadas, o resultado mais adequado se deu com a adição do composto em disco contendo ertapenem, com especificidade de 100%, porém com sensibilidade de apenas 50%. CONCLUSÃO: Novos estudos são necessários, sobretudo no que diz respeito à padronização da técnica e aos insumos utilizados, pois o método se revela promissor na triagem de cepas produtoras de KPC.

INTRODUCTION: The production of Klebsiella pneumoniae carbapenemases enzymes (KPC) has become an important and worrisome resistance mechanism. Furthermore, tests that combine high sensitivity and high specificity for the detection of these enzymes are scarce. OBJECTIVE: To validate the inhibition test by 3-aminophenyl boronic acid as a phenotypic screening method for KPC-producing strains by comparing the results with confirmatory polymerase chain reaction testing (PCR). METHODS: We evaluated the use of 3-aminophenyl boronic acid applied on disks with imipenem, meropenem and ertapenem antibiotics. 36 strains were positive and 12 were negative, all confirmed by PCR. Three different concentrations of boronic acid were also tested: 300, 400 and 600 µg. RESULTS: Among the positive strains, the results were more accurate with the addition of the compound to the ertapenem disk, presenting 100 % specificity and 50% sensitivity. CONCLUSION: Further studies are required, mainly regarding the standardization of the technique and materials, since the method seems to be promising as to the screening of KPC strains.

Risk factors for KPC-producing Klebsiella pneumoniae bacteremia

The molecular epidemiology of carbapenemase-producing Klebsiella pneumoniae (KPC) has been largely investigated, but limited clinical information is available. A case-control study was performed to evaluate the risk factors for KPC bacteremia in hospitalized patients. Cases were patients with KPC bacteremia and controls were patients with non-KPC bacteremia. A total of 85 patients were included, 18 (21.2%) were KPC, and 67 (78.8%) were non-KPC (40 [59.7%] of them were extended-spectrum beta-lactamase producers). All KPC isolates were type 2 producers. These isolates belong to five distinct clones. Multivariate analysis showed that age (odds ratio [OR], 1.06; 95% confidence interval [CI], 1.02 - 1.11; p = 0.004), presence of mechanical ventilation (OR, 11.1; 95% CI, 1.92 - 63.3; p = 0.007) and fluoroquinolone exposure during hospitalization (OR, 28.9; 95% CI, 1.85 - 454.6; p = 0.02) were independent risk factors for KPC in patients with K. pneumoniae bacteremia. Factors associated with severity of illness, such as age and mechanical ventilation, seem to be the main risks factors for KPC. Fluoroquinolones use might be a risk factor for KPC bacteremia. Further investigations on risk factors for KPC are warranted.

Risk factors for KPC-producing Klebsiella pneumoniae bacteremia.

The molecular epidemiology of carbapenemase-producing Klebsiella pneumoniae (KPC) has been largely investigated, but limited clinical information is available. A case-control study was performed to evaluate the risk factors for KPC bacteremia in hospitalized patients. Cases were patients with KPC bacteremia and controls were patients with non-KPC bacteremia. A total of 85 patients were included, 18 (21.2%) were KPC, and 67 (78.8%) were non-KPC (40 [59.7%] of them were extended-spectrum beta-lactamase producers). All KPC isolates were type 2 producers. These isolates belong to five distinct clones. Multivariate analysis showed that age (odds ratio [OR], 1.06; 95% confidence interval [CI], 1.02 - 1.11; p = 0.004), presence of mechanical ventilation (OR, 11.1; 95% CI, 1.92 - 63.3; p = 0.007) and fluoroquinolone exposure during hospitalization (OR, 28.9; 95% CI, 1.85 - 454.6; p = 0.02) were independent risk factors for KPC in patients with K. pneumoniae bacteremia. Factors associated with severity of illness, such as age and mechanical ventilation, seem to be the main risks factors for KPC. Fluoroquinolones use might be a risk factor for KPC bacteremia. Further investigations on risk factors for KPC are warranted.