Antimicrobial susceptibilities of Listeria monocytogenes human strains isolated from 1970 to 2008 in Brazil

Abstract

INTRODUCTION: Listeria monocytogenes is the causative agent of listeriosis, a foodborne illness that affects mainly pregnant women, the elderly and immunocompromised patients. The primary treatment is a combination of ampicillin with an aminoglycoside, in addition to a second-choice drug represented by chloramphenicol, erythromycin, tetracycline and rifampicin. The aim of this study was to analyze the antimicrobial susceptibility profile of strains isolated from human sources in the last four decades. METHODS: Sixty-eight strains were selected from the culture collection of the Laboratory of Bacterial Zoonoses/LABZOO/FIOCRUZ isolated in different regions of Brazil from 1970 to 2008 and primarily isolated from cerebrospinal fluid and blood culture. Susceptibility tests to antimicrobials drugs were evaluated using the criteria established by Soussy using the Kirby-Bauer method and E-Test strips were used to determine the minimum inhibitory concentration (MIC). RESULTS: Among the strains tested, serovar L4b (60.3%) was the most prevalent, followed by serovar 1/2a (20.6%), 1/2b (13.2%) and the more uncommon serovars 1/2c, 3b and 4ab (5.9%). All strains were susceptible to ampicillin, cephalothin, erythromycin, gentamicin, teicoplanin and vancomycin. Only one strain (1.5%) showed resistance to rifampin, and two (3%) were resistant to trimethoprim-sulfamethoxazole. MICs with values up to 2μg/ml reinforce the need for microbiological surveillance. CONCLUSIONS: The study demonstrated low prevalence of strains resistant to the antimicrobial drugs indicated in the treatment of human listeriosis. Monitoring antimicrobial resistance profile is still very important to determine adequate treatment, especially in immunocompromised patients.

Characterization of antibiotic resistance in Listeria spp. isolated from slaughterhouse environments, pork and human infections

“…[13]. In Brazil, this resistance profile has not been commonly observed, and Listeria isolates are susceptible to most antibiotics [26][27][28]. For this reason, the study of antibiotic resistance in Listeria has not progressed to the point that the molecular mechanisms of resistance should receive significant attention.…”

“…For this reason, the study of antibiotic resistance in Listeria has not progressed to the point that the molecular mechanisms of resistance should receive significant attention. However, the emergence of clindamycin, oxacillin, and fluoroquinolone resistance is noteworthy [28,29] and demands attention due to the risk of increasing multidrug resistance in Listeria and the possibility of its transference to other bacteria.…”

An overview of Listeria monocytogenes contamination in ready to eat meat, dairy and fishery foods

“…al., 2012;ANDRADE et al, 2014;RISTORI et al, 2014) as well as its isolation in hospitalized patients, but without associating with the consumption of a particular food (CRUZ et al, 2008;MARTINS et al, 2010;REIS et al, 2011), it can be inferred that there is a possibility of non notification of listeriosis human cases in Brazil. So, despite these reports, there is not enough data about the occurrence of the disease in population and implied food.…”

Panorama de la infección por Listeria monocytogenes

“…Autores brasileños estudiaron muestras de pacientes con infección por L. monocytogenes aisladas desde 1970 a 2008, siendo 100% de éstas susceptibles a ampicilina 59 , lo mismo ocurrió en aislados a partir de alimentos en Colombia 60 . Sin embargo, en México se ha reportado cepas multi-resistentes en muestras tomadas de pescados y agua de mar, que podrían ser una amenaza potencial para el ser humano 61 .…”