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Purpose:To evaluate the minimum inhibitory concentration (MIC) of GTA against these microorganisms and alternative disinfectants for high-level disinfection (HLD). Methods: Reference mycobacteria and clinical M. massiliense strains were included in this study. Active cultures were submitted to susceptibility qualitative tests with GTA dilutions (ranging from 1.5% to 8%), and commercial orthophthaldehyde (OPA) and peracetic acid (PA) -based solutions, during the period of exposure as recommended by National Agency of Sanitary Surveillance for HLD. Results: All reference and M. massiliense non-BRA100 strains, recovered from sputum, were susceptible to any GTA concentration, OPA and PA solutions. M. massiliense BRA100 strains presented MIC of 8% GTA and were susceptible to OPA and PA. Conclusion: M. massiliense BRA100 strain is resistant to high GTA concentrations (up to 7%), which proves that this product is non-effective against specific rapidly growing mycobacteria and should be substituted by OPA or PA -based solutions for HLD. Key words: Mycobacterium Infections. Videolaparoscopy. Disinfection. Glutaraldehyde. RESUMOObjetivo: Avaliar a concentração mínima inibitória (CMI) de GTA frente a M. massiliense e a susceptibilidade a produtos alternativos para desinfecção de alto nível (DAN). Métodos: Cepas de M. massiliense de origem clínica e de referência foram incluídas no estudo. As culturas ativadas foram submetidas a testes qualitativos com diluições de GTA (de 1,5% a 8%) e com soluções comerciais de ortoftaldeído (OPA) ou ácido peracético (PA), utilizando os tempos de exposição recomendados pela Agência Nacional de Vigilância Sanitária para DAN. Resultados: Todas as cepas de referência e M. massiliense não-BRA100, obtida de escarro, foram susceptíveis às concentrações de GTA, e soluções de OPA e PA. As cepas de M. massiliense BRA100 apresentaram CMI de 8% para GTA e foram susceptíveis a OPA e PA. Conclusão: M. massiliense BRA100 é resistente a altas concentrações de GTA (até 7%), o que demonstra que esse composto não é eficaz, e deve ser substituído por OPA ou PA nos processos de DAN.

We appreciate the interest of Dr Saliou and colleagues in our study, and we congratulate them on their work that searches for the improvement of microbial quality surveillance of gastrointestinal endoscopes and automatic endoscope reprocessors. Endoscope surveillance through bacterial cultures can assess the sufficiency of reprocessing to prevent infectious outbreaks. Methodologic details vary among the published articles and guidelines, and certainly some adaptation of culturing procedures may yield better results. The main guideline recently published by the Centers for Diseases Control and Prevention 1 has suggested qualitative and quantitative protocols with 48 hours as the incubation time for recovering the usual pathogens. Although the same incubation time has been recommended by recently established protocols for reprocessing endoscopes, 2,3 evidence of outbreaks of infection has been reported despite microbiologic surveillance. 4,5 Many limitations have been associated with endoscope culturing protocols, including the lack of standardized sampling techniques, culture methods, and interpretation of results. 6 Hence, in our study, we focused on evaluating the procedures routinely used in the setting of an endoscopy unit. 3,7 Conversely, we agree that incubating the samples for more than 48 hours could result in better rates of bacterial recovery, especially those obtained from biofilms, as described by Saliou et al. 8 It is intriguing to notice, however, that some studies have described increased biofilm growth rates in comparison with planktonic (free-floating microorganisms) growth rates, whereas others have reported exactly the opposite. 9,10 Finally, we understand that the data from Sailou and colleagues are relevant, and they also appear to be complementary to our study. Together, both studies strongly reinforce the need for continuous adaptation of the guidelines and protocols regarding endoscope surveillance, particularly in the context of biofilm-forming instruments.