RESUMEN
BACKGROUND: Stenotrophomonas maltophilia is a gram-negative bacillus and a nosocomial pathogen in immunocompromised patients. Trimethoprim/sulfamethoxazole (TMP/SMX) is the drug of choice for treating S. maltophilia infection; however, resistance to TMP/SMX is increasing. In this study, we investigated the relationship between the incidence of TMP/SMX resistance and the presence of sul genes and mobile elements. METHODS: A total of 120 S. maltophilia isolates were collected from 3 university hospitals between April 2007 and April 2009. Antimicrobial susceptibilities were determined using the disk diffusion method. PCR and DNA sequencing were conducted for the detection of sul1, sul2, class 1 integron, and ISCR2 element. Repetitive extragenic palindromic sequence-based PCR (REP-PCR) was carried out to evaluate the genetic relatedness. RESULTS: The TMP/SMX-resistant (R) isolates harbored a significantly higher proportion of sul1 gene and class 1 integron than TMP/SMX-susceptible (S) isolates (P<0.001). Seventeen of 28 isolates with sul1 also had a class 1 integron, but none of the isolates without sul1 had a class 1 integron. The identified gene cassettes within class 1 integrons include aacA4, aadA1, aac6'-II, and qac. None of the 120 isolates carried sul2, glmM, or ISCR2 element. REP-PCR did not show any genetic relatedness among the isolates. CONCLUSIONS: In Korea, the resistance of S. maltophilia isolates to TMP/SMX is due to sul1 within a class 1 integron rather than to sul2. The class 1 integron also harbors multiple antibiotic resistance genes in addition to sul1, and therefore it could mediate multidrug resistance in S. maltophilia.
Asunto(s)
Humanos , Antibacterianos/farmacología , Proteínas Bacterianas/genética , Proteínas Portadoras/genética , ADN Bacteriano/genética , Pruebas Antimicrobianas de Difusión por Disco , Farmacorresistencia Bacteriana Múltiple/genética , Integrones/genética , Reacción en Cadena de la Polimerasa , Stenotrophomonas maltophilia/efectos de los fármacos , Combinación Trimetoprim y Sulfametoxazol/farmacologíaRESUMEN
BACKGROUND: Extended-spectrum beta-lactamases (ESBLs) are cephalosporinases that confer resistance to a wide variety of oxyimino cephalosporins and create serious therapeutic problems. Although ESBLs have been reported with increasing frequency in Korea, their prevalence and genotypic distribution in Daejeon remain unknown. This study was designed to evaluate the occurrence and genotypic distributions of ESBL-producing Escherichia coli and Klebsiella pneumoniae in Daejeon. METHODS: We tested a total of 427 isolates of E. coli and K. pneumoniae at Chungnam National University Hospital during the period from March to September 2006. ESBL production was determined by the Clinical and Laboratory Standards Institute ESBL confirmatory test; minimum inhibitory concentrations of beta-lactam antibiotics were determined by the broth dilution method. The ceftazidime or cefotaxime resistance of the ESBL-producers was transferred to azide-resistant E. coli J53 by conjugation. Searches for ESBL genes were performed by PCR amplification, and the genotypes of ESBLs were determined by direct nucleotide sequence analysis of the amplified products. The pIs of ESBL were determined by isoelectric focusing. RESULTS: The proportion of ESBL-producers was 10% of the E. coli and 28% of the K. pneumoniae isolates. The prevalence of ESBL-positive isolates was 60% in the intensive care units and 18.7% in the general wards. The most prevalent ESBL genotype in E. coli isolates was blaCTX-M and in K. pneumoniae was blaSHV-12. CONCLUSIONS: E. coli and K. pneumoniae isolates producing SHV-12 or CTX-M-type ESBLs are widespread in Daejeon.
Asunto(s)
Humanos , Antibacterianos/uso terapéutico , Pruebas Antimicrobianas de Difusión por Disco , Farmacorresistencia Bacteriana , Escherichia coli/efectos de los fármacos , Infecciones por Escherichia coli/tratamiento farmacológico , Genotipo , Infecciones por Klebsiella/tratamiento farmacológico , Klebsiella pneumoniae/efectos de los fármacos , Corea (Geográfico) , Resistencia betalactámica , beta-Lactamasas/análisis , beta-Lactamas/uso terapéuticoRESUMEN
A 35 year old woman was admitted to the hospital owing to her nausea, vomiting, oliguria and petechia with re-administration of rifampin. Laboratory tests were performed and they showed a hemoglobin level of 8.6 g/dL, a leukocyte count of 7,660/microliter, a platelet count of 1,000/microliter, a blood urea nitrogen level of 92.3 mg/dL and a creatinine level of 10.6 mg/dL. The Direct Coombs' test and anti-platelet antibody test were positive. Hemolytic anemia combined with thrombocytopenia and acute renal failure related to rifampin was suspected. We proved the formation of immune complex with anti-rifampin antibody and rifampin by in vitro testing. Hemolytic anemia combined with thrombocytopenia and acute renal failure after treatment with rifampin is a rare condition. We report here on such a case along with a brief review of the related literature.