RESUMEN
OBJECTIVES: Enterococci have gained attention during the past decade as important nosocomial pathogens. Their increasing prevalence has been paralleled by the occurrence of multidrug-resistant and high-level aminoglycoside-resistant strains. This study isolated Enterococcus spp. from hospital samples and determined their antibiotic resistance profile, focusing on aminoglycosides, and associated resistance mechanisms. METHODS: A total of 195 enterococci from hospital samples in Tehran were studied. Isolates were identified by biochemical reactions. Antimicrobial resistance was determined by disk diffusion. The vancomycin MIC for vancomycin-resistant isolates was determined by agar dilution. Detection of aminoglycoside resistance genes and intI1 and intI2 gene was performed by PCR. RESULTS: The majority of isolates were Enterococcus faecalis (65.1%), followed by Enterococcus faecium (31.8%), Enterococcus gallinarum (2.6%) and Enterococcus solitarius (0.5%). According to antibiogram results, 42.1% of isolates were high-level gentamicin-resistant (HLGR) and 40.5% were high-level streptomycin-resistant (HLSR). There was a high prevalence of aac(6')-Ie-aph(2")-Ia (96.3%) among HLGR isolates. ant(6)-Ia and aadA were identified in 93.7% and 64.6% of HLSR isolates, respectively. aph(2'')-Ic was detected in 7 isolates (3.6%) and aph(2'')-Ib in only 4 isolates (2.1%); no isolates harboured aph(2'')-Id, intI1 or intI2. CONCLUSION: Multidrug resistance was higher among HLGR and HLSR isolates compared with non-HLGR and non-HLSR isolates, which may result in limited treatment options. More than 50% of isolates were susceptible to aminoglycosides, thus correct identification in clinical laboratories and administration of these antibiotics can result in decreased used of antibiotics such as vancomycin and linezolid and help to reduce the emergence of resistance to these drugs.
Asunto(s)
Aminoglicósidos/farmacología , Proteínas Bacterianas/genética , Farmacorresistencia Bacteriana Múltiple , Enterococcus/clasificación , Infecciones Urinarias/microbiología , Pruebas Antimicrobianas de Difusión por Disco , Enterococcus/efectos de los fármacos , Enterococcus/aislamiento & purificación , Gentamicinas/farmacología , Humanos , Irán/epidemiología , Filogenia , Prevalencia , Estreptomicina/farmacología , Infecciones Urinarias/tratamiento farmacológico , Resistencia a la VancomicinaRESUMEN
OBJECTIVE: To study virulence and regulatory genes (hlyA, ctxB, tcpI) in clinical strains of Vibrio cholerae (V. cholerae), simultaneously. METHODS: Three important genes, tcpI, hlyA and ctxB were used for detection of toxigenic and pathogenic V. cholera by chain reaction assay method. RESULTS: According to the results of the PCR, the incidence of hlyA, tcpI, and ctxB genes in clinical isolates was obtained as 94.7% (72 sample), 90.8% (69 sample), and 92.1% (70 sample), respectively. Five strains possessed all genes except ctxB, six strains possessed all genes except tcpI, four strains possessed all genes except hlyA, one strain possessed only hlyA and 60 strains contained a combination of three genes, Including hlyA, ctxB and tcpI. CONCLUSIONS: Result show that this method could be reliable to detect toxigenic-pathogenic strains of V. cholerae in Iran.
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Cólera/microbiología , Reacción en Cadena de la Polimerasa Multiplex/métodos , Vibrio cholerae/genética , Proteínas Bacterianas/genética , ADN Bacteriano/análisis , ADN Bacteriano/genética , Heces/microbiología , Genes Bacterianos/genética , Proteínas Hemolisinas/genética , Humanos , Irán , Proteínas Represoras/genética , Sensibilidad y Especificidad , Vibrio cholerae/clasificación , Vibrio cholerae/aislamiento & purificación , Virulencia/genéticaRESUMEN
BACKGROUND: Vancomycin-resistant enterococci pose an emerging health risk. The limitation in therapeutic options has resulted in the development of new drugs such as quinupristin/ dalfopristin and linezolid. AIM, SETTING AND DESIGN: This study investigated the species prevalence and antibacterial resistance among enterococci isolated in selected Tehran hospitals. MATERIALS AND METHODS: Between March 2006 and August 2007, 200 enterococcal isolates from urine, blood, stool and wound were recovered in 2 teaching hospitals of Tehran province. Susceptibility of all isolates was tested against vancomycin, teicoplanin and linezolid antibiotics by disk diffusion and agar dilution method. RESULTS AND CONCLUSION: Seventeen (8.5%), 6 (3%) and 4 (2%) of the isolates were resistant to vancomycin, teicoplanin and linezolid, respectively. Within the vancomycin-resistant isolates, 6 (35.2%), 4 (25%) and 1 (5.88%) showed vanA, vanB and vanC genotype patterns, respectively. Four (23.5%) of VRE isolates were resistant to linezolid with minimum inhibitory concentrations between 16 and 32 microg/mL. Two linezolid vancomycin resistant enterococci were E. faecium.
Asunto(s)
Acetamidas/farmacología , Antiinfecciosos/farmacología , Farmacorresistencia Bacteriana Múltiple , Enterococcus/efectos de los fármacos , Infecciones por Bacterias Grampositivas/microbiología , Oxazolidinonas/farmacología , Resistencia a la Vancomicina , Farmacorresistencia Bacteriana Múltiple/genética , Enterococcus/genética , Enterococcus/aislamiento & purificación , Infecciones por Bacterias Grampositivas/tratamiento farmacológico , Infecciones por Bacterias Grampositivas/epidemiología , Hospitales de Enseñanza , Humanos , Irán/epidemiología , Linezolid , Pruebas de Sensibilidad Microbiana , Prevalencia , Prueba Bactericida de Suero , Teicoplanina/farmacología , Resistencia a la Vancomicina/genéticaRESUMEN
Bordetella pertussis infects the respiratory tract of the human host and causes whooping cough in children. The nature of immunity against Bordetella pertussis infection and disease is poorly understood. The aim of this study was to investigate cell mediated immunity in mice immunized with outer membrane component of cell wall, of B. Pertussis. A group of mice were immunized with outer membrane complex (OMC) and killed whole cell (WCV) of B. pertussis, with an interval of 2 weeks. During a period of 7 weeks following the immunization, lymphocytes were isolated from lymph nodes of immunized mice. The in vitro proliferative response of isolated lymphocyte to stimulation with 20 ig of 30 and 69 kDa outer membrane protein (OMP) were measured as parameters for cell mediated immunity (CMI). The data were expressed as mean count per minute (CPM)x103 after subtraction of the CPM of unstimulated control cultures. Lymphoblastogenic response was observed in immunized mice with WCV and OMC. At 30 days of post immunization a significant increase in response to 30 and 69 kDa OMP was observed, a small decrease in the response was evident against P30 and P69 at 60 and 120 days of post immunization, but the response was still higher than what was observed in control mice. Current findings indicate strongly the potential of outer membrane protein component of B. perlussis in proliferating lymphocytes in the mice.