ABSTRACT
Mycobacterium tuberculosis strains resistant to streptomycin (SM), isoniazid (INH), and/or rifampin (RIF) as determined by the conventional Lõwenstein-Jensen proportion method (LJPM) were compared with the E test, a minimum inhibitory concentration susceptibility method. Discrepant isolates were further evaluated by BACTEC and by DNA sequence analyses for mutations in genes most often associated with resistance to these drugs (rpsL, katG, inhA, and rpoB). Preliminary discordant E test results were seen in 75 percent of isolates resistant to SM and in 11 percent to INH. Discordance improved for these two drugs (63 percent) for SM and none for INH when isolates were re-tested but worsened for RIF (30 percent). Despite good agreement between phenotypic results and sequencing analyses, wild type profiles were detected on resistant strains mainly for SM and INH. It should be aware that susceptible isolates according to molecular methods might contain other mechanisms of resistance. Although reproducibility of the LJPM susceptibility method has been established, variable E test results for some M. tuberculosis isolates poses questions regarding its reproducibility particularly the impact of E test performance which may vary among laboratories despite adherence to recommended protocols. Further studies must be done to enlarge the evaluated samples and looked possible mutations outside of the hot spot sequenced gene among discrepant strains.
Subject(s)
Humans , Antitubercular Agents , Mycobacterium tuberculosis , Base Sequence , Drug Resistance, Microbial , Isoniazid , Microbial Sensitivity Tests , Rifampin , StreptomycinABSTRACT
We used a slide culture technique to detect tubercle bacilli surviving in sputum smears (n=46) after conventional heat fixation and Ziehl-Neelsen staining. In all heat-fixed sputum smears, tubercle bacilli survived after time 0 (n=22), 24 h (n=7), 48 h (n=7), 72 h (n=4), and seven days (n=6). None of the stained sputum smears showed growth on slide cultures. Viable tubercle bacilli remaining in heat-fixed sputum smears for at least seven days may present an infection risk to laboratory staff. Thus, sputum smears should be stained immediately by the Ziehl-Neelsen method or stored in a safe container to avoid transmission of tuberculosis
Subject(s)
Humans , Coloring Agents , Hot Temperature , Nontuberculous Mycobacteria/growth & development , Sputum/microbiology , Mycobacterium Infections, Nontuberculous/diagnosis , Mycobacterium Infections, Nontuberculous/transmission , Time Factors , Tuberculosis, Pulmonary/diagnosis , Tuberculosis, Pulmonary/transmissionABSTRACT
O efeito de saböes e preparaçöes anti-sépticas foi avaliado quanto à remoçäo de amostras de Klebsiella pneumoniae e Staphylococcus aureus, procedentes de pacientes hospitalizados, artificialmente aplicadas sobre as mäos de voluntários humanos. Os experimentos foram realizados segundo 4 blocos aleatorizados 4 x 3, e os resultados determinados por análise de variância, tendo como variável resposta o log do fator de reduçäo (log da contagem inicial menos o log da contagem final). No 1§ e 2§ bloco näo foi evidenciada diferença nos tratamentos com sabäo de coco, hexaclorofeno e álcool 70% (p > 0,05), ao contrário do observado no 3§ e 4§ experimento, onde a polivinilpirrolidona-iodo mostrou diferenças altamente significativas (p << 0,05) em relaçäo à clorohexidina e ao sabäo medicinal a base de triclorocarbanilida. Todos os produtos mostraram-se eficientes, reduzindo 88-99% das populaçöes bacterianas aplicadas sobre as mäos