Seroprevalence of Listeria monocytogenes in HIV infected pregnant women from Brazil.

OBJECTIVE: To describe the prevalence and factors associated with serologic response to Listeria monocytogenes in HIV infected and uninfected pregnant women in Brazil. METHODS: Cross-sectional study, pregnant women after 14 weeks of gestational age were enrolled. Positive serologic test for L. monocytogenes was defined as titers >1:80 (agglutination test). Comparisons were performed using logistic regression. RESULTS: A total of 213 women were enrolled, 73 (34%) were HIV infected. 55 women were seroreactive for L. monocytogenes, 27 (37%) HIV-infected and 28 (20%) HIV-uninfected (p < 0.01). Considering the diet record, white cheese consumption was associated with seroreactivity (p < 0.01). In the group of pregnant women living with HIV, the variables associated with L. monocytogenes positive serology were: lower CD4+ cells count at study entry OR=4.8 (95%CI=1.1-19.8) and having neonates admitted to the intensive care unit OR=5.9 (95%CI=1.01-34.9). CONCLUSION: Positive serology for Listeria monocytogenes was associated with HIV infection. Brazilian women should avoid white cheese during pregnancy.

Prevalence of Listeria monocytogenes fecal carriers in HIV-infected and -uninfected pregnant women from Brazil.

OBJECTIVE: The aim of this study is to describe the prevalence of Listeria spp. in feces of HIV-infected and -uninfected pregnant women in Brazil. METHODS: Cross-sectional study. Women on their second or third trimester of pregnancy were submitted to a clinical questionnaire and feces collection. The feces were inoculated on selective media and identification by biochemical tests combined with PCR. RESULTS: A total of 213 pregnant women were enrolled: 73 (34%) HIV-infected and 140 (66%) -non-infected. The prevalence of Listeria spp. and L. monocytogenes in feces of HIV-infected women were 8.2% and 2.7%. In the HIV-uninfected were 8.6% and 2.9% (p-values = 0.98 and 0.66, respectively). CONCLUSION: The prevalence of fecal carriers of Listeria spp. and L. monocytogenes was not associated with HIV infection during pregnancy.

Evaluation of MALDI-TOF MS as a tool for detection of Listeria spp. directly from selective enrichment broth from food and stool samples.

We evaluated the detection of Listeria spp. using MALDI-TOF MS directly in enrichment broths, without isolated colonies, with naturally contaminated food and stool samples. The success rate was 77%. Considering the reduced time for diagnosis and the success rate, this is a promising screening tool, but more tests are needed to determine its viability.

Rapid detection of Yersinia enterocolitica serotype O:3 using a duplex PCR assay.

Yersinia enterocolitica, a member of the Enterobacteriaceae family, is a zoonotic agent that causes gastrointestinal diseases and some extraintestinal disorders in humans. Y. enterocolitica ssp. palearctica bioserotype 4/O:3 is the primary pathogenic bioserotype in Europe, where it has a high public health relevance. The isolation and identification of Y. enterocolitica from various sources on selective media have been seldom successful due to several reasons. In an attempt to overcome the problems associated with traditional culture-based methods, we developed a single duplex PCR assay for the detection of Y. enterocolitica ssp. palearctica bioserotype 4/O:3 using DNA extracted from a source. We combined the primer for tufA (elongation factor Tu) with the primer for rfbC (the biosynthesis of the O side chain) in one single reaction, which showed good results when we analyzed 88 Yersinia strains and when it was tested in the DNA from stool samples of two groups of pregnant women, one comprising HIV-positive women and the other comprising of HIV-negative women. Furthermore, the duplex PCR assay was found to be 16 times better in detecting Yersinia spp. in stool samples than the culture-based method. In addition, it was found to be a rapid screening method for the detection of Y. enterocolitica serotype O:3, and it could still detect other Y. enterocolitica serotypes and Yersinia species as well. We anticipate that the duplex PCR assay could be a useful tool for hospital and veterinary surveillance studies on Yersinia worldwide.