Caracterização molecular dos mecanismos de resistência aos antibióticos β-lactâmicos em Klebsiella spp. isoladas de infecções de corrente sanguínea do Projeto SCOPE Brasil
Arquivos
Data
2009
Autores
Monteiro, Jussimara 
Orientadores
Pignatari, Antonio Carlos Campos
Tipo
Tese de doutorado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
Objetivos: Avaliar (i) o perfil de sensibilidade aos antimicrobianos e caracterizar os
tipos de β-lactamases de espectro ampliado, entre isolados clínicos de Klebsiella spp.
(KSP); (ii) os mecanismos de resistência em isolados clínicos de Klebsiella
pneumoniae (KPN) que apresentaram diminuição de sensibilidade aos carbapenens;
(iii) a acurácia do teste de Hodge para detecção de carbapenemases Material e
Métodos: Foram avaliadas 167 amostras de KSP isoladas do primeiro episódio de
infecção de corrente sanguínea (ICS) de pacientes hospitalizados em 15 centros
médicos de diferentes regiões do país, participantes do programa de vigilância SCOPE
Brasil, entre junho de 2007 e dezembro de 2008. Todas as amostras foram
submetidas a re-identificação e teste de sensibilidade pelo sistema automatizado BD
Phoenix. As amostras foram classificadas em dois grupos de acordo com a
sensibilidade in vitro aos agentes β-lactâmicos e detecção de ESβL: (i) KSP produtora
de ESβL e (ii) KSP não produtora de ESβL. As amostras representativas do grupo
KSP produtora de ESβL foram submetidas a testes fenotípicos e moleculares. Os
principais tipos de β-lactamases foram caracterizados pela reação em cadeia da
polimerase (PCR), seguido pelo sequenciamento dos produtos amplificados. Testes
adicionais foram realizados para o subgrupo KPN produtora de ESβL e resistente a
ertapenem (KPN-ESβL-RE). Resultados: As espécies mais comuns foram K.
pneumoniae (n=158), seguida por K. oxytoca (n=8) e K. ozaenae (n=1). Altas taxas de
resistência aos antimicrobianos foram constatadas, sendo que 56,3% das amostras
foram classificadas como produtoras de ESβL. As ESβL mais frequentes foram CTXM-2,
CTX-M-15, SHV-5 e SHV-12. Isolados clínicos contendo concomitantemente dois
tipos de ESβL (CTX e SHV) foram detectados somente nas regiões Nordeste e
Sudeste. O mecanismo de resistência detectado nas amostras KPN-ESβL-RE foi a
produção de cefotaximase, associada à alteração das porinas OmpK35 e/ou OmpK36.
O teste de Hodge apresentou baixa acurácia nessas amostras. Conclusões:
Evidenciamos a disseminação de CTX-M-2 e a emergência de CTX-M-15, associada a
alterações nas porinas OmpK35 e OmpK36 em amostras de KSP isoladas de ICS em
hospitais brasileiros. Nenhuma carbapenemase foi detectada
Objectives: To evaluate (i) the antimicrobial susceptibility profile of Klebsiella spp. (KSP) clinical isolates and characterize the extended spectrum β-lactamases. (ii) the resistance mechanisms in Klebsiella spp. clinical isolates that showed decrease of carbapenem susceptibility. (iii) the accuracy of the Hodge Test for carbapenemase activity detection. Material and Methods: 167 KPS strains were evaluated in this study. The strains were isolated from the first bloodstream infection episode of patients hospitalized at 15 medical centers from different regions of the country participating of SCOPE Brazillian surveillance program, between June, 2007 and December, 2008. The isolates were re-identified and susceptibility tested by the automated system BD Phoenix and classified in two groups according antimicrobial susceptibility profile and ESβL detection: (i) KSP ESβL-producing and (ii) KSP ESβL-non-producing. KSP ESβL-producing were submitted to phenotypic and molecular tests. The β-lactamase types were characterized by PCR, followed by DNA sequencing. Additional tests were performed for ertapenem resistant K. pneumoniae ESβL-producing (KPN-ESβL-ER). Results: The most common species were K. pneumoniae (n=158), followed by K. oxytoca (n=8) and K. ozaenae (n=1). High rates of antimicrobial resistance were observed and 56.3% of isolates were classified as ESβL-producing. The most frequent ESβL were CTX-M-2, CTX-M-15, SHV-5 and SHV-12. Clinical isolates with two ESβL types (CTX and SHV) were only detected in the northeast and southeast regions. The resistance mechanism detected in the KPN-ESβL-ER isolates was the cefotaximase production associated with OmpK35 and/or OmpK36 porin alteration. The Hodge test showed low accuracy in these isolates. Conclusions: We showed the dissemination of CTX-M-2 and emergence of CTX-M-15, associated with OmpK35 and OmpK36 porin modification, in KSP strains isolated from bloodstream infection in Brazilian hospitals. No carbapenemase was detected.
Objectives: To evaluate (i) the antimicrobial susceptibility profile of Klebsiella spp. (KSP) clinical isolates and characterize the extended spectrum β-lactamases. (ii) the resistance mechanisms in Klebsiella spp. clinical isolates that showed decrease of carbapenem susceptibility. (iii) the accuracy of the Hodge Test for carbapenemase activity detection. Material and Methods: 167 KPS strains were evaluated in this study. The strains were isolated from the first bloodstream infection episode of patients hospitalized at 15 medical centers from different regions of the country participating of SCOPE Brazillian surveillance program, between June, 2007 and December, 2008. The isolates were re-identified and susceptibility tested by the automated system BD Phoenix and classified in two groups according antimicrobial susceptibility profile and ESβL detection: (i) KSP ESβL-producing and (ii) KSP ESβL-non-producing. KSP ESβL-producing were submitted to phenotypic and molecular tests. The β-lactamase types were characterized by PCR, followed by DNA sequencing. Additional tests were performed for ertapenem resistant K. pneumoniae ESβL-producing (KPN-ESβL-ER). Results: The most common species were K. pneumoniae (n=158), followed by K. oxytoca (n=8) and K. ozaenae (n=1). High rates of antimicrobial resistance were observed and 56.3% of isolates were classified as ESβL-producing. The most frequent ESβL were CTX-M-2, CTX-M-15, SHV-5 and SHV-12. Clinical isolates with two ESβL types (CTX and SHV) were only detected in the northeast and southeast regions. The resistance mechanism detected in the KPN-ESβL-ER isolates was the cefotaximase production associated with OmpK35 and/or OmpK36 porin alteration. The Hodge test showed low accuracy in these isolates. Conclusions: We showed the dissemination of CTX-M-2 and emergence of CTX-M-15, associated with OmpK35 and OmpK36 porin modification, in KSP strains isolated from bloodstream infection in Brazilian hospitals. No carbapenemase was detected.
Descrição
Citação
MONTEIRO, Jussimara. Caracterização molecular dos mecanismos de resistência aos antibióticos β- Lactâmicos em Klebsiella spp. isoladas de infecções de corrente sanguínea do Projeto SCOPE Brasil. 2009. 145 f. Tese (Doutorado em Ciências) – Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, 2009.