Molecular epidemiology and drug resistance of Acinetobacter baumannii isolated from a regional hospital in the Brazilian Amazon region

Abstract INTRODUCTION: In this study, we report a clonal dissemination of carbapenem resistant Acinetobacter baumannii isolates due to the acquisition of blaOXA-23 in a regional hospital located in Brazilian Amazon Region. METHODS: The isolates were identified by MALDI-TOF and the carbapenemase-encoding genes were detected by multiplex-PCR. The genetic similarity was investigated by pulsed-field gel electrophoresis (PFGE). RESULTS: Only 10 (55.6%) isolates harbored the gene bla OXA-23. PFGE analysis revealed that these isolates belong to a single clone. CONCLUSIONS: This dissemination strategy indicates the need for surveillance, adoption of control procedures defined in guidelines, and the careful administration of antimicrobials should be reinforced.

Temporal evolution of antimicrobial resistance among Neisseria gonorrhoeae clinical isolates in the most populated South American Metropolitan Region

A total of 124 Neisseria gonorrhoeae isolates recovered during a 12-year period (2003-2015) from outpatients assisted at Centro de Referência e Treinamento DST/AIDS-CRT of São Paulo city, Brazil, were analysed. The following resistance rates were observed: penicillin-59.6%, ciprofloxacin-15.3%, and azithromycin-6.7%. Although reduced susceptibility to these drugs was observed since 2003, no ceftriaxone-resistant isolates were detected. Ciprofloxacin- and azithromycin non-susceptible isolates were grouped in 11 clusters. Mutations were detected in GyrA and ParC of isolates 124 and 260, and a C2611T substitution on 23S rRNA alleles was also observed in isolate 260. Both isolates belonged to ST1901/ST6210 (MSLT/NG-MAST schemes).

Detection and analysis of different interactions between resistance mechanisms and carbapenems in clinical isolates of Klebsiella pneumoniae

Abstract Carbapenems are considered last-line agents for the treatment of serious infections caused by Klebsiella pneumoniae, and this microorganism may exhibit resistance to β-lactam antibiotics due to different mechanisms of resistance. We evaluated 27 isolates of K. pneumoniae resistant to carbapenems recovered from inpatients at the University Hospital of Santa Maria-RS from July 2013 to August 2014. We carried out antimicrobial susceptibility, carbapenemase detection, testing for the presence of efflux pump by broth microdilution and loss of porin by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Genetic similarity was evaluated by ERIC-PCR. High levels of resistance were verified by the minimum inhibitory concentration for the antimicrobials tested. The blaKPC gene was present in 89% of the clinical isolates. Blue-Carba and combined disk with AFB tests showed 100% concordance, while the combined disk test with EDTA showed a high number of false-positives (48%) compared with the gold-standard genotypic test. Four isolates showed a phenotypic resistance profile consistent with the overexpression of the efflux pump, and all clinical isolates had lost one or both porins. The ERIC-PCR dendrogram demonstrated the presence of nine clusters. The main mechanism of resistance to carbapenems found in the assessed isolates was the presence of the blaKPC gene.

Carbapenem-resistant and cephalosporin-susceptible: a worrisome phenotype among Pseudomonas aeruginosa clinical isolates in Brazil

Abstract The mechanisms involved in the uncommon resistance phenotype, carbapenem resistance and broad-spectrum cephalosporin susceptibility, were investigated in 25 Pseudomonas aeruginosa clinical isolates that exhibited this phenotype, which were recovered from three different hospitals located in São Paulo, Brazil. The antimicrobial susceptibility profile was determined by CLSI broth microdilution. β-lactamase-encoding genes were investigated by PCR followed by DNA sequencing. Carbapenem hydrolysis activity was investigated by spectrophotometer and MALDI-TOF assays. The mRNA transcription level of oprD was assessed by qRT-PCR and the outer membrane proteins profile was evaluated by SDS-PAGE. Genetic relationship among P. aeruginosa isolates was assessed by PFGE. Carbapenems hydrolysis was not detected by carbapenemase assay in the carbapenem-resistant and cephalosporin-susceptible P. aueruginosa clinical isolates. OprD decreased expression was observed in all P. aeruginosa isolates by qRT-PCR. The outer membrane protein profile by SDS-PAGE suggested a change in the expression of the 46 kDa porin that could correspond to OprD porin. The isolates were clustered into 17 genotypes without predominance of a specific PFGE pattern. These results emphasize the involvement of multiple chromosomal mechanisms in carbapenem-resistance among clinical isolates of P. aeruginosa, alert for adaptation of P. aeruginosa clinical isolates under antimicrobial selective pressure and make aware of the emergence of an uncommon phenotype among P. aeruginosa clinical isolates.

Identification of São Paulo metallo-beta-lactamase-1-producing Pseudomonas aeruginosa in the Central-West region of Brazil: a case study

Abstract: Metallo-beta-lactamase production is an important mechanism for carbapenem resistance of Pseudomonas aeruginosa , which represents an emerging public health challenge. We report the case of a patient admitted to an intensive care unit, with sepsis caused by multidrug-resistant São Paulo Metallo-beta-lactamase-1-producing P. aeruginosa . This is the first case of infection by this pathogenic strain in the State of Mato Grosso do Sul, Brazil. Thus, infection control measures are required for preventing future spread and outbreaks.

Antimicrobial resistance in Enterobacteriaceae in Brazil: focus on ß-lactams and polymyxins

ABSTRACT During the last 30 years there has been a dissemination of plasmid-mediated β-lactamases in Enterobacteriaceae in Brazil. Extended spectrum β-lactamases (ESBL) are widely disseminated in the hospital setting and are detected in a lower frequency in the community setting. Cefotaximases are the most frequently detected ESBL type and Klebsiella pneumoniae is the predominant species among ESBL producers. Klebsiella pneumoniae carbapenemase-producing Enterobacteriaceae became widely disseminated in Brazil during the last decade and KPC production is currently the most frequent resistance mechanism (96.2%) in carbapenem resistant K. pneumoniae. To date KPC-2 is the only variant reported in Brazil. Polymyxin B resistance in KPC-2-producing K. pneumoniae has come to an alarming rate of 27.1% in 2015 in São Paulo, the largest city in Brazil. New Delhi metallo-β-lactamase was detected in Brazil in 2013, has been reported in different Brazilian states but are not widely disseminated. Antimicrobial resistance in Enterobacteriaceae in Brazil is a very serious problem that needs urgent actions which includes both more strict adherence to infection control measures and more judicious use of antimicrobials.

Antimicrobial resistance in Enterobacteriaceae in Brazil: focus on -lactams and polymyxins

ABSTRACT During the last 30 years there has been a dissemination of plasmid-mediated -lactamases in Enterobacteriaceae in Brazil. Extended spectrum -lactamases (ESBL) are widely disseminated in the hospital setting and are detected in a lower frequency in the community setting. Cefotaximases are the most frequently detected ESBL type and Klebsiella pneumoniae is the predominant species among ESBL producers. Klebsiella pneumoniae carbapenemase-producing Enterobacteriaceae became widely disseminated in Brazil during the last decade and KPC production is currently the most frequent resistance mechanism (96.2%) in carbapenem resistant K. pneumoniae. To date KPC-2 is the only variant reported in Brazil. Polymyxin B resistance in KPC-2-producing K. pneumoniae has come to an alarming rate of 27.1% in 2015 in São Paulo, the largest city in Brazil. New Delhi metallo--lactamase was detected in Brazil in 2013, has been reported in different Brazilian states but are not widely disseminated. Antimicrobial resistance in Enterobacteriaceae in Brazil is a very serious problem that needs urgent actions which includes both more strict adherence to infection control measures and more judicious use of antimicrobials.

KPC-2-producing Klebsiella pneumoniae in a hospital in the Midwest region of Brazil

The emergence of β-lactamase-producing Enterobacteriaceae in the last few decades has become major challenge faced by hospitals. In this study, isolates of Klebsiella pneumoniae carbapenemase-2 (KPC-2)-producing K. pneumoniae from a tertiary hospital in Mato Grosso do Sul, Brazil, were characterized. Bacterial identification was performed by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF; Bruker Daltonics, Germany) mass spectrometry. The minimum inhibitory concentrations of carbapenems were determined using the agar dilution method as recommended by the Clinical Laboratory Standards Institute guidelines. Carbapenemase production was detected using the modified Hodge test (MHT) and polymerase chain reaction (PCR), followed by DNA sequencing. Of 360 (12.2%) K. pneumoniae isolates obtained between May 2009 and May 2010, 44 (12.2%) were carbapenem nonsusceptible. Of these 44 isolates, thirty-six K. pneumoniae isolates that were positive by MHT and PCR carried the blaKPC-2 gene. Thus, KPC-2producing Klebsiella pneumoniae has been present in a Brazilian hospital located in the Midwest region since at least 2009.

Early dissemination of OXA-72-producing Acinetobacter baumannii strain in Colombia: a case report

Nosocomial infections caused by carbapenem-resistant Acinetobacter baumannii isolates have reached epidemic levels in past decades. Currently this microorganism is responsible for outbreaks of difficult eradication and with high mortality rates worldwide. We herein report a rare case of an OXA-72-producing A. baumannii isolate colonizing a 47-year-old male patient with peritonitis due to abdominal stab wound, four years earlier than the first report of this carbapenemase in Acinetobacter pittii in Colombia. Although OXA-72 presents a low prevalence compared with OXA-23, our study demonstrated that A. baumannii isolates carrying the blaOXA-72 gene were present in the hospital environment in Colombia and could act as a reservoir for further spread to other Acinetobacter species, like A. pittii, causing carbapenem-resistance.

Antimicrobial susceptibility testing for Helicobacter pylori isolates from Brazilian children and adolescents: comparing agar dilution, E-test, and disk diffusion

Antimicrobial susceptibility testing for Helicobacter pylori is increasingly important due to resistance to the most used antimicrobials agents. Only agar dilution method is approved by CLSI, but it is difficult to perform routinely. We evaluated the reliability of E-test and disk diffusion comparing to agar dilution method on Helicobacter pylori antimicrobial susceptibility testing. Susceptibility testing was performed for amoxicillin, clarithromycin, furazolidone, metronidazole and tetracycline using E-test, disk-diffusion and agar dilution method in 77 consecutive Helicobacter pylori strains from dyspeptic children and adolescents. Resistance rates were: amoxicillin - 10.4%, 9% and 68.8%; clarithromycin - 19.5%, 20.8%, 36.3%; metronidazole - 40.2%33.7%, 38.9%, respectively by agar dilution, E-test and disk diffusion method. Furazolidone and tetracycline showed no resistance rates. Metronidazole presented strong correlation to E-test (r = 0.7992, p < 0.0001) and disk diffusion method (r=-0.6962, p < 0.0001). Clarithromycin presented moderate correlation to E-test (r = 0.6369, p < 0.0001) and disk diffusion method (r=-0.5656, p < 0.0001). Amoxicillin presented weak correlation to E-test (r = 0.3565, p = 0.0015) and disk diffusion (r=-0.3565, p = 0.0015). Tetracycline presented weak correlation with E-test (r = 0.2346, p = 0.04) and furazolidone to disk diffusion (r=-0.0288, p = 0.8038). E-test presented better agreement with gold standard. It is an easy and reliable method for Helicobacter pylori susceptibility testing. Disk diffusion method presented high disagreement and high rates of major errors.

Evaluation of MALDI-TOF MS in the microbiology laboratory / Avaliação da técnica de MALDI-TOF MS no laboratório de microbiologia

Rapid identification of microorganisms by the clinical microbiology laboratory is of crucial importance for optimal patients’ management and treatment. In general, bacterial identification by conventional methods requires 18-24 hours for colony isolation and at least 24 additional hours for species identification. New technologies in microbiology have focused on the rapid diagnosis of bloodstream infections, since they are associated with high morbidity and mortality rates.

A rápida identificação de microrganismos no laboratório de microbiologia clínica é de extrema importância para direcionar o manejo e o tratamento de pacientes. Geralmente, a identificação bacteriana por métodos bioquímicos convencionais necessita de 18 a 24 horas para o crescimento e o isolamento da colônia bacteriana e, pelo menos, 24 horas adicionais para a identificação da espécie. Novas tecnologias em microbiologia têm focado no desenvolvimento de métodos relacionados com o diagnóstico rápido das infecções da corrente sanguínea, uma vez que essas infecções são associadas à alta morbimortalidade.

Metallo-β-lactamase-production in meropenem-susceptible Pseudomonas aeruginosa isolates: risk for silent spread

The aim of this study was to characterize two metallo-β-lactamases (MBLs)-producing Pseudomonas aeruginosa clinical isolates showing meropenem susceptibility. Antimicrobial susceptibility was assessed by automated testing and Clinical and Laboratory Standards Institute agar dilution method. MBL production was investigated by phenotypic tests. Molecular typing was determined by pulsed field gel electrophoresis (PFGE). MBL-encoding genes, as well as their genetic context, were identified by polymerase chain reaction (PCR) and sequencing. The location of blaIMP-16 was determined by plasmid electrophoresis, Southern blot and hybridization. Transcriptional levels of blaIMP-16, mexB, mexD, mexF, mexY, ampC and oprD were determined by semi-quantitative real time PCR. The P. aeruginosa isolates studied, Pa30 and Pa43, showed imipenem and meropenem susceptibility by automated testing. Agar dilution assays confirmed meropenem susceptibility whereas both isolates showed low level of imipenem resistance. Pa30 and Pa43 were phenotypically detected as MBL producers. PFGE revealed their clonal relatedness. blaIMP-16 was identified in both isolates, carried as a single cassette in a class 1 integron that was embedded in a plasmid of about 60-Kb. Pa30 and Pa43 overexpressed MexAB-OprM, MexCD-OprJ and MexXY-OprM efflux systems and showed basal transcriptional levels of ampC and oprD. MBL-producing P. aeruginosa that are not resistant to meropenem may represent a risk for therapeutic failure and act as silent reservoirs of MBL-encoding genes.

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.

Prevalence and clinical outcomes of episodes of ventilator-associated pneumonia caused by SPM-1-producing and non-producing imipenem-resistant Pseudomonas aeruginosa / Prevalência e evolução clínica de episódios de pneumonia associada à ventilação mecânica causada por Pseudomonas aeruginosa resistente a imipenem produtoras e não-produtoras de SPM-1

INTRODUCTION: Pseudomonas aeruginosa is a leading cause of ventilator-associated pneumonia (VAP) and exhibits high rates of resistance to several antimicrobial drugs. The carbapenens are usually the drugs of choice against this microorganism. However, the carbapenem resistance has increased among these strains worldwide. The presence of metallo-β-lactamases (MBL) has been pointed out as a major mechanism of resistance among these strains. No previous study addressed outcomes of respiratory infections caused by these strains. METHODS: Our group sought to analyze the epidemiology and clinical outcomes of patients with VAP caused by imipenem-resistant P. aeruginosa. A total of 29 clinical isolates of carbapenem-resistant Pseudomonas aeruginosa were screened for metallo-β-lactamase (MBL) genes. RESULTS: Demographic and clinical variables were similar between the SPM-1-producing and non-SPM-1-producing group. Five (17.2 percent) isolates were positive for blaSPM-1. No other MBL gene was found. All patients were treated with polymyxin B. The infection-related mortality was 40 percent and 54.2 percent for SPM-1-producing and -non-producing isolates, respectively. CONCLUSIONS: There were no differences in epidemiological and clinical outcomes between the two groups.

INTRODUÇÃO: Pseudomonas aeruginosa é uma importante causa de pneumonia associada à ventilação mecânica (PAV) e exibe altas taxas de resistência a vários antimicrobianos. Os carbapenens são usualmente as drogas de escolha para esse microorganismo. Contudo, a resistência a carbapenens tem crescido entre essas amostras em todo o mundo. A presença de metalo- β-lactamase (MBL) tem sido apontado como um importante mecanismo de resistência nessas cepas. Nenhum estudo prévio avaliou desfechos clínicos de infecções respiratórias causadas por essas amostras MÉTODOS: Nosso grupo analisou a epidemiologia e evolução clínica de episódios de PAV causada por P. aeruginosa resistente a imipenem. Um total de vinte e nove isolados clínicos de Pseudomonas aeruginosa resistente a carbapenem foram avaliados quanto à presença de genes para metalo-β-lactamase (MBL). RESULTADOS: Variáveis clínicas e demográficas foram similares entre o grupo produtor de SPM-1 e o não-produtor. Cinco (17,2 por cento) isolados foram positivos para blaSPM-1. Nenhum outro gene para MBL foi encontrado. Todos os pacientes foram tratados com polimixina B. A mortalidade relacionada à infecção foi de 40 por cento e 50 por cento respectivamente para os isolados produtores de SPM-1 e não-produtores de SPM-1. CONCLUSÕES: Nao houve diferença entre os dados epidemiológicos e a evolução clínica entre os dois grupos.

Cefepime versus extended spectrum β-lactamase-producing Enterobacteriaceae

The objective of this study was to evaluate the susceptibility to cefepime of a large group of ESBL- producing enterobacteria recently isolated in a Brazilian teaching hospital . The study included 280 strains of ESBL-producing enterobacteria, isolated between 2005 and 2008. The presence of the genes blaCTX-M, blaTEM and blaSHV was determined by PCR and confirmed by nucleotide sequencing. Susceptibility testing for cefepime was performed by disc-diffusion, agar dilution method and E-test®. Among the isolates, 34 (12.1 percent) presented a cefepime inhibition zone > 21 and MIC < 8 mg/L by agar dilution and E-strip methods. The use of cefepime for the treatment of infections caused by ESBL-producing bacteria has been controversial. Some studies of PD/PK show the probability of achieving the required PD parameters for cefepime, when the MICs were < 8 mg/L, whereas others have reported therapeutic failure with the same MIC. Additional data is essential to come to terms about the report and treatment with cefepime in ESBL-producing organisms especially when these microorganisms are isolated from sterile sites and from critically ill patients.

Avaliação das metodologias M.I.C.E.®, Etest® e microdiluição em caldo para determinação da CIM em isolados clínicos / Evaluation of M.I.C.E.TM, Etest® and CLSI broth microdilution methods for antimicrobial susceptibility testing of nosocomial bacterial isolates

INTRODUÇÃO: As fitas Oxoid® M.I.C.Evaluator® (M.I.C.E., Thermo Fisher Scientific, Basingstoke, UK), recém-lançadas no mercado brasileiro, representam uma alternativa rápida para a realização de testes de sensibilidade a antimicrobianos (TSA). OBJETIVO: Avaliar o desempenho da metodologia M.I.C.E. em relação à microdiluição em caldo (teste de referência) e ao Etest® (BioMérieux, Marcy l'Étoile, France). Material e métodos: Foram selecionados 160 isolados bacterianos, sendo P. aeruginosa (20), Acinetobacter spp. (20), K. pneumoniae (20), E. coli (20), S. aureus (20), Staphylococcus coagulase-negativa (20), E. faecalis (20) e E. faecium (20). Os TSAs foram realizados por microdiluição em caldo, Etest e M.I.C.E., seguindo-se as recomendações do Clinical Laboratory Standards Institute (CLSI, 2009) e dos respectivos fabricantes. Os resultados foram interpretados segundo os critérios estabelecidos pelo CLSI e comparados por análise de regressão. RESULTADOS: Avaliando-se todas as combinações de antimicrobianos vs. a espécie bacteriana, o desempenho da metodologia M.I.C.E. foi muito bom, apresentando uma concordância geral (variação na concentração inibitória mínima [CIM] ± 1-log2) > 90 por cento, exceto para cefotaxima (85 por cento) e vancomicina (76,3 por cento), quando em comparação com os resultados da metodologia de referência. Quando comparado com o Etest, a metodologia M.I.C.E. apresentou concordância geral > 96 por cento, com exceção para a combinação amoxicilina/ácido clavulânico (67,5 por cento). CONCLUSÃO: Os resultados do TSA obtidos pela metodologia M.I.C.E. apresentaram boa correlação com aqueles obtidos pela microdiluição em caldo e pelo Etest, indicando que essa metodologia é uma alternativa rápida para a determinação da CIM pelos laboratórios de microbiologia clínica. Atenção especial deve ser dada á determinação da CIM para a combinação amoxicilina/ácido clavulânico.

INTRODUCTION: The Oxoid® M.I.C.EvaluatorTM methodology (M.I.C.E., Thermo Fisher Scientific, Basingstoke, UK), recently released into the market, represents a rapid alternative to antimicrobial susceptibility testing. OBJECTIVE: The objective of this study was to evaluate the performance of M.I.C.E. methodology in relation to broth microdilution (reference test) and Etest® (BioMérieux, Marcy l'Étoile, France). Material and method: A total of 160 bacterial isolates were collected comprising the following species: P. aeruginosa (20), Acinetobacter spp. (20), K. pneumoniae (20), E. coli (20), S. aureus (20), coagulase-negative Staphylococcus (20), E. faecalis (20) and E. faecium (20). Following Clinical Laboratory Standands Institute (CLSI) standards (2009) and the manufacturers' recommendations, antimicrobial susceptibility testing was performed using broth microdilution method, Etest and M.I.C.E. The results were interpreted according to the criteria established by CLSI and compared through regression analysis. RESULTS: All antimicrobial combinations vs. bacterial species were evaluated and M.I.C.E. methodology yielded good results with general correlation (MIC variation ± 1-log2) > 90 percent, except for cefotaxime (85 percent) and vancomycin (76.3 percent) when compared with the reference method. The M.I.C.E. results compared to Etest showed general correlation (> 96 percent), except for amoxicillin/clavulanic acid (67.5 percent) combination. CONCLUSION: AST results obtained from M.I.C.E. methodology showed a good correlation with those from broth microdilution and Etest, which corroborates its time effectiveness in the determination of MIC. However, the combination of amoxicillin/clavulanic acid requires further attention.

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.

Antimicrobial effect of two endodontic medicaments with different exposure times, and the morphologic alterations caused to Enterococcus faecalis / Efeito antimicrobiano de dois medicamentos endodônticos com diferentes exposições, e as alterações morfológicas causadas a Enterococcus faecalis

PURPOSE: The aim of this study was to verify the antimicrobial effect of calcium hydroxide and iodoform on Enterococcus faecalis with different exposure times evaluating the bacterial morphologic alterations. METHODS: The antibacterial action was investigated in culture broth after zero, seven, fourteen and twenty-one days. Five mL samples were analyzed morphologically on the seventh day by transmission electron microscopy. The data of the antibacterial test were analyzed by Fisher's exact test. RESULTS: The results revealed that between the seventh and fourteenth day, there was a decrease in bacterial growth with both medicaments (P=0.098), where they were eliminated between the fourteenth and twenty-first day. Transmission electronic microscopy showed alterations in the morphologic structures. CONCLUSION: It concluded that both medicaments kill Enterococcus faecalis, with an exposure time of 7 to 14 days, where no cell viability is seen after this period due to irreversible alterations in bacterial cell morphology.

OBJETIVO: O presente estudo verificou o efeito antibacteriano do hidróxido de cálcio e do iodofórmio em Enterococcus faecalis com diferentes tempos de exposição, avaliando as alterações morfológicas bacteriana. MÉTODOS: A ação antibacteriana foi investigada através de caldo de cultura após zero, sete, 14 e 21 dias, e assim, 5 mL das amostras do sétimo dia foram analisadas morfologicamente por microscopia eletrônica de transmissão. Os dados da ação antibacteriana em caldo foram analisados pelo teste Exato de Fisher. RESULTADOS: Os resultados revelaram que entre o 7º e o 14º dia houve diminuição do crescimento bacteriano com ambos os medicamentos (P=0,098), onde a eliminação bacteriana ocorreu entre o 14º e 21º dia. A microscopia eletrônica de transmissão apresentou alterações na estutura morfolófica bacteriana. CONCLUSÃO: Pode-se concluir que ambos os medicamentos destroem o Enterococcus faecalis com tempo de exposição de 7 a 14 dias, onde a viabilidade celular não é observada após este período devido alterações irreversíveis na morfologia celular bacteriana.

Carbapenem-resistant Pseudomonas aeruginosa: clonal spread in southern Brazil and in the state of Goiás

This study evaluated the clonal spread of carbapenem-resistant P. aeruginosa producing SPM-1 type metallo-β-lactamase (MBL), at the university hospital of Florianópolis, Santa Catarina, Brazil, compared to an epidemic clone previously reported, as well as strains collected in other three Brazilian states. Among the isolates, 17 (62 percent) were clonal and highly related to strains from other regions of Brazil. Six clonal strains harbored the blaSPM-1 gene. The finding of a unique SPM-1 producer clone suggests that its dissemination has contributed to the high resistance to carbapenems in Brazilian hospitals.