RESUMO
Extended-Spectrum Beta-lactamase producing Enterobacteriales (ESBL-PE) in fecal carriage have become a global health concern. Detection of putative virulent ESBL-producing E.coli (ESBL-EC) isolates among asymptomatic carriers is a threatening issue in public health. The aim of this study was to investigate the intestinal carriage of ESBL-EC, phylo-groups and clonal relatedness among putative virulent groups of ESBL-EC isolated from fecal carriages. A total of 120 rectal swabs; 50.8% (61/120) from inpatients of intensive care unit (ICU) and 49.2% (59/120) from outpatients were collected. The ESBL-EC screening was performed by using MacConkey agar supplemented with cefotaxime. PCR assays were applied for determination of phylo-groups, detection of ESBL and carbapenemase genes. Conjugation experiment, plasmid replicon typing and Multilocus Sequence Typing (MLST) were performed for putative virulent phylo-groups. Totally, of 120 studied individuals, 60.0% (72/120) were carrier for ESBL-EC. The rate of blaCTX-M-15, blaTEM, blaSHV was 90.2% (65/72), 50.0% (36/72) and 5.5% (4/72), respectively. The frequency of phylo-groups A, B1, B2, C, D, and F were 20.8% (15/72), 6.9% (5/72), 20.8% (15/72), 2.7% (2/72), 13.8 (10/72) and 12.5% (9/72), respectively. In conjugation experiments, of 6 tested isolates, 5 had conjugative plasmids. The most prevalent plasmid types belonged to IncF incompatibility groups. The MLST analysis showed that the main sequence types among ESBL-EC isolates were ST769 and ST472. The current study provides novel information about the presence of the ESBL-EC isolates, particularly putative virulent phylo-groups among fecal carriages in Iran. Our data revealed that there was almost high ST heterogeneity among putative ESBL-EC isolates. In order to implementation of effective infection control program, detection of fecal carriage in appropriate time typically at the beginning of admission to the hospital is recommended.
Assuntos
Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Fezes/microbiologia , Resistência beta-Lactâmica/genética , beta-Lactamases/metabolismo , Adolescente , Adulto , Idoso , Criança , Escherichia coli/enzimologia , Escherichia coli/genética , Escherichia coli/patogenicidade , Feminino , Regulação Bacteriana da Expressão Gênica , Regulação Enzimológica da Expressão Gênica , Humanos , Masculino , Pessoa de Meia-Idade , Filogenia , Virulência , Adulto Jovem , beta-Lactamases/genéticaRESUMO
Acinetobacter baumannii is considered as a major cause of nosocomial infection worldwide. Various vaccine formulations have been mostly studied based on secreted or surface-exposed proteins of A. baumannii in murine models. Serum resistance proteins are critical virulence factors in bloodstream infections. AbOmpA and PKF are two major factors involved in serum resistance and could be considered as promising vaccine targets. In this study IgG1, IgG2c, Total-IgG concentrations, survival rates and spleen bacterial loads were studied in C57/BL mice model according to PKF, AbOmpA and AbOmpA + PKF vaccine formulations. The findings showed significant raises of IgG2c and Total-IgG in all three vaccinated groups in comparison with the control group. Whereas, there were low concentrations of IgG1 in all immunization plans. Colony counts of mice spleen showed the bacterial load of PKF plan had the most decrease of bacterial load (DBL = 5 log10â¯CFU/g). Taken together, this evaluation indicated that PKF vaccination plan induced a polarized Th1 response and rendered an effective protection against bloodstream infection caused by A. baumannii.
Assuntos
Infecções por Acinetobacter/imunologia , Infecções por Acinetobacter/prevenção & controle , Acinetobacter baumannii/patogenicidade , Formação de Anticorpos/imunologia , Proteínas da Membrana Bacteriana Externa/imunologia , Fatores R/sangue , Sepse/microbiologia , Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/genética , Animais , Carga Bacteriana , Proteínas da Membrana Bacteriana Externa/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Vacinas Bacterianas/imunologia , Clonagem Molecular , Modelos Animais de Doenças , Genes Bacterianos/genética , Imunização , Imunoglobulina G/sangue , Camundongos , Camundongos Endogâmicos C57BL , Fatores R/imunologia , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Baço/imunologia , Taxa de Sobrevida , Vacinas Sintéticas/genética , Vacinas Sintéticas/imunologia , Fatores de Virulência/genética , Fatores de Virulência/imunologiaRESUMO
Successful clones of Acinetobacter baumannii cause a variety of nosocomial infections through serum resistance, biofilm formation, and antimicrobial resistance as virulence capabilities. Fifty clinical isolates of multidrug-resistant (MDR) A. baumannii were analyzed for clonal relatedness, serum resistance, biofilm formation, and in vivo assays. Furthermore, some virulence genes, sequence variation of ompA, and its expression were studied. The MLST (multilocus sequence typing) results showed that there were three sequence types among MDR isolates including ST2 (64%, 32/50), ST513 (30%, 15/50), and ST1 (6%, 3/50). The data showed that the clinical isolates recovered from sputum had mostly high biofilm-formation capacity, while isolates recovered from host interior fluids had high serum resistance. The results of PCR assays and in silico analysis represented patterns of virulence genes and even ompA sequence variations among MDR isolates which were clonally dependent. While quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analysis showed that bacteremia-producing strains in C57/BL6 mice significantly overexpress ompA (P < 0.05) and have a direct relation with the level of IL-6 in bloodstream of mice. Moreover, the expressions of ompA among indistinguishable clones (ST2 or ST513) were clonally independent.
