Pheno- and genotypic characterization of Listeria monocytogenes clinical isolates from the southwestern region of the State of São Paulo, Brazil

Abstract

Considering the lack of information available in Brazil concerning listeriosis, the present study aimed to analyze phenotypic and genotypically Listeria monocytogenes clinical isolates from the Southwestern region of the State of São Paulo, Brazil. From January 1995 to May 2005, thirteen isolates of L. monocytogenes from twelve patients with listeriosis were sent to the Adolfo Lutz Institute (Campinas Regional Laboratory, São Paulo, Brazil). The antimicrobial susceptibility of the isolates was evaluated by the microdilution broth method for ampicillin, gentamicin, trimethoprim, sulfamethoxazole and vancomycin. They were also serotyped (Denka Seiken, Japan), and sub-typed by PFGE employing ApaI and AscI and the American CDC protocol. None of the isolates showed resistance to the antibiotics tested; however, seven of them presented increased values for sulfamethoxazole MICs. Ten isolates belonged to serotype 4b, two to serotype 1/2a and only one to serotype 1/2b. After digestion with ApaI and AscI, the strains were distributed in 3 different groups according to their profile. It was observed that the spatial or temporally unrelated strains exhibited similar PFGE profiles, indicating a possible clonal relationship among them.

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

“…The same result was obtained by LemesMarques et al 19 , although reports in the literature demonstrate resistance to trimethoprim 25 , as well as the combination of trimethoprim-sulfamethoxazole 26,27 . MICs with values up to 2μg/ ml reinforce the need for microbiological surveillance.…”

Molecular characterization of Listeria monocytogenes isolated from animal products in a city of Northern Brazil

“…However in Brazil, data from both human and environment samples isolation has been scarce, especially in the second case. Therefore, in our country, a map of the geographical and temporal distribution of the occurrence of L. monocytogenes (and much less of their pulsotypes) does not yet exist (LEMES-MARQUES et al, 2007).…”

“…Even though listeriosis can be caused by any of the 13 L. monocytogens serotypes (LEMES-MARQUES et al, 2007), it is known that 1/2a, 1/2b and 4b serotypes are responsible for almost 90% of outbreaks and sporadic cases worldwide (LÓPEZ et al, 2006). In this study, it was found that the isolates of L. monocytogenes serotypes 4b, 1/2a and 1/2b were strongly correlated within the same serotypes and, in some cases, between the different serotypes, indicating a common origin.…”

“…GRAVES et al (1999) Conventional techniques by themselves cannot detect the source of listeriosis outbreaks; however, molecular subtyping methods are an useful tool in this determination. Among these methods, pulsed-fi eld gel electrophoresis (PFGE) offers great sensitivity along with a high discriminatory power, and it is considered the gold standard method for L. monocytogenes subtyping (TENOVER et al 1997;FUGETT et al, 2007;LEMES-MARQUES et al, 2007). PFGE can also be used in long-term studies both to determine the persistence of a species in an environment, or for determining external contamination into an environment (SENCZEK et al, 2000;MORETRO & LANGSRUD, 2004).…”

“…Along with the lack of control and study of listeriosis in Brazil, LEMES-MARQUES et al (2007) include the diffi culties in tracing the bacterial types involved in the outbreaks, the lack of notifi cation and the delay in obtaining fi nal results in conventional medical tests.…”