Assuntos
Cefalosporinas/farmacologia , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/enzimologia , Resistência beta-Lactâmica , beta-Lactamases/metabolismo , Chile , Farmacorresistência Bacteriana , Humanos , Infecções por Klebsiella/diagnóstico , Infecções por Klebsiella/tratamento farmacológico , Klebsiella pneumoniae/isolamento & purificação , Testes de Sensibilidade Microbiana , Sensibilidade e Especificidade , beta-Lactamases/efeitos dos fármacosRESUMO
BACKGROUND: The resistance of Shigella flexneri to antimicrobial agents can be associated to the presence of integrons that may contain and express antimicrobial resistance gene cassettes. AIM: To study antimicrobial resistance and the presence of integrons and antimicrobial gene cassettes in Shigella flexneri strains. MATERIAL AND METHODS: In vitro susceptibility to 27 antimicrobials was studied in twenty four Shigella flexneri strains isolated from stools. The presence of integrons class 1, 2 and 3 and antimicrobial resistance gene cassettes was investigated by polymerase chain reaction (PCR) using specific primers for each gene. RESULTS: Most strains were resistant to one of the following antimicrobials: ampicillin, sulphonamide, trimethoprim, tetracycline, streptomycin, sulfamethoxazole-trimethoprim or chloramphenicol. Twenty nine percent were simultaneously resistant to all these antimicrobials. Integrons class 1 and 2 were found in 19 strains (79 per cent). Class 3 integrons were not found. Gene cassettes dfrA1 and ant(3")I were associated to integrons class 2 in most strains (15/20, 75 per cent). Genes cat, tetB and blarTEM were detected in 18/24 (75 per cent), 7/24 (29 per cent) and 4/24 (17 per cent) of the strains, respectively and were not associated to any of the studied integrons. Genes that codify enzymes AAC(6')Ib and APH(3')VI were not detected in any strain. CONCLUSIONS: The high frequency of integrons found in the studied strains, could partly explain the increasing antimicrobial resistance of Shigella flexneri strains, isolated in Chile.
Assuntos
Humanos , Genes Bacterianos/efeitos dos fármacos , Integrons/genética , Farmacorresistência Bacteriana/genética , Shigella flexneri/efeitos dos fármacos , Dados de Sequência Molecular , Genes Bacterianos/genética , Oligonucleotídeos/genética , Reação em Cadeia da Polimerase , Farmacorresistência Bacteriana Múltipla/genética , Sequência de Aminoácidos , Shigella flexneri/genética , Testes de Sensibilidade MicrobianaRESUMO
Members of the family Enterobacteriaceae are responsible for a variety of nosocomial infections, treatment of which is limited due to their increasing resistance to antibiotics. Some bacterial genes encoding antibiotic resistance comprise the major part of gene cassettes, most of which are associated with integrons. In this work, the carriage of class 1, 2 and 3 integrons was investigated in 191 Enterobacteriaceae isolates from clinical specimens of hospitalized patients. Class 1 integrons were found to be the most common, whereas no class 3 integrons were detected. The variable regions of 13 class 1 integrons were characterized and four types were found. Type 1 harbours only ant(3")I, type 2 harbours ant(2")I and ant(3")I, type 3 harbours aac(6')Ib and ant(3")I and type 4 lacks inserted gene cassettes.
Assuntos
Antibacterianos/farmacologia , Enterobacteriaceae/genética , Integrons/genética , Aminoglicosídeos , Chile , DNA Bacteriano/genética , Farmacorresistência Bacteriana , Eletroforese em Gel de Poliacrilamida , Enterobacteriaceae/efeitos dos fármacos , Infecções por Enterobacteriaceae/microbiologia , Humanos , Testes de Sensibilidade Microbiana , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Resistance of Gram-negative bacilli to third-generation cephalosporins has been increasing due to the production of extended-spectrum beta-lactamases. In this work, the activities of cefepime, cefotaxime, ceftazidime, and aztreonam, alone and in association with clavulanic acid, against isolates of Klebsiella pneumoniae and Escherichia coli are compared. These isolates produce extended-spectrum beta-lactamases as shown by the synergy tests and by the decrease in the MICs of cephalosporins in the presence of clavulanic acid. Cefepime was the most active compound against these microorganisms. In addition, the microorganisms exhibited lower frequencies of resistance to this cephalosporin.
Assuntos
Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Klebsiella pneumoniae/efeitos dos fármacos , beta-Lactamases/metabolismo , Aztreonam/farmacologia , Cefepima , Cefotaxima/farmacologia , Ceftazidima/farmacologia , Cefalosporinas/farmacologia , Chile , Ácido Clavulânico/farmacologia , Sinergismo Farmacológico , Escherichia coli/enzimologia , Escherichia coli/isolamento & purificação , Infecções por Escherichia coli/microbiologia , Hospitais , Humanos , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/enzimologia , Klebsiella pneumoniae/isolamento & purificação , Testes de Sensibilidade MicrobianaRESUMO
Antibiotic resistant bacteria from commercial demersal and pelagic fish captured in the Concepción Bay, Chile were investigated. Viable counts of antibiotic resistant bacteria isolated from gill and intestinal content samples showed high frequencies of resistance to ampicillin, streptomycin and tetracycline, while the proportion of chloramphenicol resistance was rather low. A high incidence of resistance to ampicillin, streptomycin, tetracycline and nitrofurantoin, as well as almost an absence of resistance to gentamicin, amikacin and cotrimoxazole was found among selected isolates which represented the resistant bacterial population. These strains mainly belonged to Vibrionaceae and Enterobacteriaceae and were predominantly resistant to 3 and 4 antibacterials. Isolates from demersal fish exhibited resistance to as many as 8-10 compounds, whereas those from pelagic fish were resistant to seven or fewer antibiotics. These results suggest that Chilean commercial fishes residing in waters near the disposals of urban sewage might play a role as carriers of antibiotic resistant bacteria prompting a health risk to public health for fish consumers.
Assuntos
Resistência a Medicamentos , Enterobacteriaceae/efeitos dos fármacos , Peixes/microbiologia , Vibrionaceae/efeitos dos fármacos , Animais , Chile , Enterobacteriaceae/isolamento & purificação , Enterobacteriaceae/fisiologia , Monitoramento Ambiental , Pesqueiros , Humanos , Saúde Pública , Eliminação de Resíduos , Medição de Risco , Esgotos , Vibrionaceae/isolamento & purificação , Vibrionaceae/fisiologiaRESUMO
BACKGROUND: Acinetobacter baumannii is an important etiological agent causing nosocomial infections. High level of resistance for different kind of antimicrobials has been observed, including beta-lactam antibiotics. This feature, chromosomal or plasmid encoded, has been associated to integrons harbouring antibiotic resistance gene cassettes. AIMS: To investigate the presence of integrons among clinical isolates resistant to third generation cephalosporins (3GC). MATERIAL AND METHODS: One hundred A. baumannii strains isolated from several Chilean hospitals were included in this study. Minimal inhibitory concentrations (MIC) of 3GC by an agar dilution method were carried out. Integrons class 1, 2 and 3 were investigated by colony blot hybridisation and confirmed by PCR. RESULTS: High level of resistance to all assayed 3GC was observed. On the other hand, integrón class 2 was the most prevalent (77% of isolates) followed by integron class 1 (52%). Forty six percent of isolates hybridised with probes for both of them. However, no positive hybridisation was detected for integron class 3. CONCLUSIONS: Nevertheless, most isolates harboured one or both class of integron; there was no direct relationship between the presence of these genetic structures and the resistance to this kind of beta-lactam antibiotics.
Assuntos
Acinetobacter/efeitos dos fármacos , Acinetobacter/genética , Cefoxitina/farmacologia , Ceftazidima/farmacologia , Ceftriaxona/farmacologia , Resistência às Cefalosporinas/genética , Chile , DNA Bacteriano/genética , Testes de Sensibilidade Microbiana , Hibridização de Ácido Nucleico , Reação em Cadeia da PolimeraseRESUMO
BACKGROUND: Bacterial vaginosis (BV) is a common disease in reproductive-age women and is associated to important gynecologic and obstetric complications. AIM: To study the occurrence of BV in apparently healthy women attending family planning clinics, using Amsel and Nugent diagnostic criteria. MATERIAL AND METHODS: Two hundred thirty nine women consulting for symptoms associated to cervicovaginitis, were studied. A sample from the lateral walls of the vagina was obtained with a sterile swab for microscopic analysis, Gram stain and amine test. RESULTS: According to Amsel and Nugent criteria a 31.1% and 31.8% BV prevalence was observed. The sensitivity and specificity of Nugent criteria, compared with Amsel criteria were 83.3% and 92.1%, respectively. CONCLUSIONS: The high prevalence of BV found in this study suggests that this vaginal infection should be diagnosed with standardized methods. Nugent criteria are economic easy to perform and sensitive and we propose that they should be used in local health centers.
Assuntos
Esfregaço Vaginal/métodos , Vaginose Bacteriana/diagnóstico , Chile/epidemiologia , Feminino , Humanos , Valor Preditivo dos Testes , Prevalência , Sensibilidade e Especificidade , Vaginose Bacteriana/epidemiologia , Vaginose Bacteriana/patologiaAssuntos
Infecções por Acinetobacter/microbiologia , Acinetobacter calcoaceticus/efeitos dos fármacos , Acinetobacter/efeitos dos fármacos , Antibacterianos/farmacologia , Acinetobacter/isolamento & purificação , Acinetobacter calcoaceticus/isolamento & purificação , Ampicilina/farmacologia , Chile , Quimioterapia Combinada/farmacologia , Humanos , Testes de Sensibilidade Microbiana , Penicilinas/farmacologia , Sulbactam/farmacologiaRESUMO
The activity of two carbapenem compounds, imipenem and meropenem, against 447 strains of Acinetobacter baumannii isolated between 1990 and 1998 in different Chilean hospitals was determined. MIC ranges, MIC(50) and MIC(90), were determined by an agar dilution method. Similar antibacterial activities were observed for both antibacterials; however, a slight increase in the MIC(50) of imipenem and meropenem, and in the MIC(90) of meropenem was found among strains isolated from 1997-1998. Although A. baumannii remains susceptible to these antibiotics, the MIC(50) and MIC(90) have increased in recent years.