Polymerase Chain Reaction Assay for Detection of Stenotrophomonas maltophilia in Cheese Samples Based on the smeT Gene.

Stenotrophomonas maltophilia is an emerging opportunistic pathogen linked not only to bacteremia, sepsis, and pneumonia but also to severe chronic enteritis. Persons with the impaired immune system are prone to be infected by S. maltophilia since its pathogenicity seems to be more associated with the host immune system than with the acquisition of specific virulence genes. In the dairy chain, S. maltophilia is linked to clinical and subclinical bovine mastitis in dairy cows, and it has been identified in cheese, and raw and pasteurized milk. There are reports of misidentification of S. maltophilia by commercial systems and PCR assays using primers based on the 23S rRNA and smeD genes, so the smeT gene is an alternative to identifying S. maltophilia by PCR due to its specificity to the S. maltophilia species. The present study reports an alternative species-specific PCR assay based on the smeT gene designed to identify S. maltophilia in cheese samples. We performed in silico and in vitro analyses to check the specificity of the primer pair. In silico analysis showed specificity of the primer pair to the species level. In vitro analysis was performed by testing the primer pair against pools of bacteria grown from 33 fresh Minas cheese samples acquired in the city of Rio de Janeiro, Brazil, without unspecific amplification.

Assessment of microbiological contamination of fresh, minimally processed, and ready-to-eat lettuces (Lactuca sativa), Rio de Janeiro State, Brazil.

UNLABELLED: This study aimed to assess the microbiological contamination of lettuces commercialized in Rio de Janeiro, Brazil, in order to investigate detection of norovirus genogroup II (NoV GII), Salmonella spp., total and fecal coliforms, such as Escherichia coli. For NoV detection samples were processed using the adsorption-elution concentration method associated to real-time quantitative polymerase chain reaction (qPCR). A total of 90 samples of lettuce including 30 whole fresh lettuces, 30 minimally processed (MP) lettuces, and 30 raw ready-to-eat (RTE) lettuce salads were randomly collected from different supermarkets (fresh and MP lettuce samples), food services, and self-service restaurants (RTE lettuce salads), all located in Rio de Janeiro, Brazil, from October 2010 to December 2011. NoV GII was not detected and PP7 bacteriophage used as internal control process (ICP) was recovered in 40.0%, 86.7%, and 76.7% of those samples, respectively. Salmonella spp. was not detected although fecal contamination has been observed by fecal coliform concentrations higher than 10(2) most probable number/g. E. coli was detected in 70.0%, 6.7%, and 30.0% of fresh, MP, and RTE samples, respectively. This study highlights the need to improve hygiene procedures at all stages of vegetable production and to show PP7 bacteriophage as an ICP for recovering RNA viruses' methods from MP and RTE lettuce samples, encouraging the evaluation of new protocols that facilitate the establishment of methodologies for NoV detection in a greater number of food microbiology laboratories. PRACTICAL APPLICATION: The PP7 bacteriophage can be used as an internal control process in methods for recovering RNA viruses from minimally processed and ready-to-eat lettuce samples.

The presence of qacA/B gene in Brazilian methicillin-resistant Staphylococcus aureus.

A total of 74 methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from three government hospitals in 2002 and 2003 were examined concerning the distribution of qacA/B gene, which is the determinant of resistance to quaternary ammonium compounds largely employed in hospital disinfection. By polymerase chain reaction the qacA/B gene was found in 80% of the isolates, which is a significant result considering it is the first time that qacA/B gene is being reported for Brazilian MRSA strains and it is presented at a high rate.

The presence of qacA/B gene in Brazilian methicillin-resistant Staphylococcus aureus

A total of 74 methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from three government hospitals in 2002 and 2003 were examined concerning the distribution of qacA/B gene, which is the determinant of resistance to quaternary ammonium compounds largely employed in hospital disinfection. By polymerase chain reaction the qacA/B gene was found in 80 percent of the isolates, which is a significant result considering it is the first time that qacA/B gene is being reported for Brazilian MRSA strains and it is presented at a high rate.