Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-10-04T22:23:59Z No. of bitstreams: 1 BrunaCostaMouraDoVale_DISSERT.pdf: 1188349 bytes, checksum: a8d43623afa31dc2808818a05740b034 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-10-13T20:53:39Z (GMT) No. of bitstreams: 1 BrunaCostaMouraDoVale_DISSERT.pdf: 1188349 bytes, checksum: a8d43623afa31dc2808818a05740b034 (MD5) / Made available in DSpace on 2017-10-13T20:53:39Z (GMT). No. of bitstreams: 1 BrunaCostaMouraDoVale_DISSERT.pdf: 1188349 bytes, checksum: a8d43623afa31dc2808818a05740b034 (MD5) Previous issue date: 2017-06-29 / As infec??es relacionadas ? assist?ncia ? sa?de (IRAS) s?o atualmente um dos principais problemas de sa?de p?blica. Os estafilococos coagulase-negativa (ECN) est?o entre as esp?cies mais prevalentes neste tipo de infec??o, devido ? sua capacidade de colonizar dispositivos m?dicos invasivos. A clorexidina ? extensivamente utilizada no ambiente hospitalar como forma de preven??o e controle de IRAS. No entanto, a literatura relata a exist?ncia de cepas com susceptibilidade reduzida ocasionada possivelmente pela presen?a dos genes qacA/B. O objetivo do estudo foi investigar a susceptibilidade ? clorexidina e sua rela??o com a presen?a dos genes qacA/B em 211 isolados de ECN provenientes de diferentes hospitais da cidade do Natal-RN. As amostras foram identificadas por testes bioqu?micos convencionais; a susceptibilidade ? antimicrobianos foi realizada pela metodologia disco-difus?o; a determina??o da Concentra??o Inibit?ria M?nima (CIM) para a clorexidina foi avaliada pela t?cnica de dilui??o em ?gar; a t?cnica da PCR foi utilizada para pesquisar os genes qacA/B e o gene mecA. No total de 211 amostras de ECN, 69% foram isolados a partir hemoculturas. As esp?cies mais frequentes foram S. epidermidis, S. hominis hominis, S. auricularis e S. haemolyticus, respectivamente. As cepas apresentaram um perfil de resist?ncia a multidrogas de 87%, incluindo resist?ncia ? oxacilina; 31% demonstraram susceptibilidade reduzida ? clorexidina. Os genes qacA/B foram detectados tanto em amostras resistentes ? clorexidina (32/32) quanto em amostras suscept?veis (17/32). Grande parte das cepas com susceptibilidade reduzida ? clorexidina exibiram tamb?m multirresist?ncia aos antibi?ticos testados (94%). A identifica??o de cepas com susceptibilidade reduzida ? clorexidina nesse estudo representa uma amea?a as pr?ticas de controle de IRAS. Apesar de todas as cepas resistentes ? clorexidina possu?rem os genes qacA/B, sua presen?a n?o foi um fator determinante para a express?o da resist?ncia, necessitando de estudos adicionais. A diminui??o da susceptibilidade ? antiss?pticos pode levar ? persist?ncia bact?rias no ambiente hospitalar contribuindo, dessa forma, para a sobreviv?ncia de cepas multirresistentes. / Health Care Associated Infections (HAI) are currently a of major public health problem. The coagulase-negative Staphylococci (CNS) are among the most prevalent species in this type of infection due to their ability to colonize invasive medical devices. Chlorhexidine is extensively used in the hospital setting as a means of prevention and control of HAI. However, the existence of strains with reduced susceptibility caused possibly by the presence of the qacA/B genes has been reported in the literature. The main of this study was to investigate the susceptibility to chlorhexidine and its relation to the presence of the qacA/B genes in 211 isolates of ECN from diferente hospitals in the city of Natal-RN. Samples were identified by standard biochemical tests; the susceptibility to antimicrobials was performed using the disc-diffusion methodology; the susceptibility to chlorhexidine was evaluated by determining the Minimum Inhibitory Concentration (MIC) by the agar dilution technique; the PCR method was used to investigate the qacA/B genes and mecA gene. In total of 211 CNS samples, 69% were isolated from blood cultures. The most frequent species were S. epidermidis, S. hominis hominis, S. auricularis and S. haemolyticus, respectively. The strains had a multidrug resistance profile of 87%, including resistance to oxacillin; 31% demonstrated reduced susceptibility to chlorhexidine. The qacA/B genes were detected in both chlorhexidine resistant (32/32) and susceptible samples (17/32). Most of the strains with reduced susceptibility to chlorhexidine also showed multidrug resistance to the tested antibiotics (94%). Identification of strains with reduced susceptibility to chlorhexidine in this study poses a threat to HAIs control practices. Although all strains resistant to chlorhexidine had the qacA/B genes, their presence was not a determining factor for the expression of the resistance, requiring additional studies. The decrease in susceptibility to antiseptics may allow bacteria to persist in the hospital environment, thus contributing to the survival of multiresistant strains.