ABSTRACT
In the province of Gipuzkoa, Spain (≈700,000 inhabitants), 7-12 episodes of human listeriosis were recorded annually during 2009-2012. However, during January 2013-February 2014, 27 episodes were detected, including 11 pregnancy-associated cases. Fifteen cases in 2 epidemiologically unrelated outbreaks were caused by a rare type of Listeria monocytogenes, sequence type 87 serotype 1/2b.
Subject(s)
Disease Outbreaks , Listeria monocytogenes/classification , Listeriosis/epidemiology , Listeriosis/microbiology , Population Surveillance , Aged , Aged, 80 and over , Female , Humans , Infant, Newborn , Listeriosis/transmission , Male , Middle Aged , Molecular Typing , Pregnancy , Serotyping , Spain/epidemiologyABSTRACT
The detection of hepatitis A virus in shellfish by reverse transcription-nested polymerase chain reaction (RT-nested PCR) is hampered mainly by low levels of virus contamination and PCR inhibitors in shellfish. In this study, we focused on getting a rapid and sensitive processing procedure for the detection of HAV by RT-nested PCR in clam samples (Tapes spp.). Two previously developed processing methods for virus concentration in shellfish have been improved upon and compared. The first method involves acid adsorption, elution, polyethylene glycol (PEG) precipitation, chloroform extraction and PEG precipitation. The second method is based on elution with a glycine buffer at pH 10, chloroform extraction and concentration by ultracentrifugation. Final clam concentrates were processed by RNA extraction or immunomagnetic capture of viruses (IMC) before the RT-nested PCR reaction. Both methods of sample processing combined with the RNA extraction from the concentrates were very efficient when they were assayed in seeded and naturally contaminated samples. The results show that the first method was more effective in removal inhibitors and the second was simpler and faster. The IMC of HAV from clam concentrates processed by method 1 was revealed to be a very effective method of simultaneously removing residual PCR inhibitors and of concentrating the virus.
Subject(s)
Bivalvia/virology , Hepatitis A virus/isolation & purification , RNA, Viral/isolation & purification , Reverse Transcriptase Polymerase Chain Reaction/methods , Shellfish/virology , Animals , Chemical Precipitation , Consumer Product Safety , Food Microbiology , Immunomagnetic Separation/methods , RNA, Viral/analysis , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
From January 1981 to December 2003, susceptibility to nalidixic acid was tested in 10,504 nontyphoid Salmonella enterica isolates from patients with acute enteric disease in Gipuzkoa, Spain. The prevalence of nalidixic acid resistance steadily increased from less than 0.5% before 1991 to 38.5% in 2003, mainly due to the increase in resistance among isolates of the most prevalent serovar, S. enterica serovar Enteritidis. For nalidixic acid-resistant isolates, the ciprofloxacin MIC was eightfold higher than that for susceptible isolates, and the nalidixic acid-resistant isolates contained a single point mutation in the gyrA gene (at codons for Ser83 or Asp87). The same mutations were found in a sample of nalidixic acid-resistant nontyphoid Salmonella strains isolated between 1999 and 2003 from retail food for human consumption. In 2003, we identified five S. enterica serovar Typhimurium clinical isolates with high-level fluoroquinolone resistance (ciprofloxacin MIC, 16 microg/ml) with two point mutations in the gyrA gene (coding for Ser83-->Phe and Asp87-->Asn) and one point mutation in the parC gene (coding for Ser80-->Arg). Strict sanitary controls are needed to avoid the spread of ciprofloxacin-resistant serovar Typhimurium isolates, and a more efficient veterinary policy must be adopted to decrease the large burden of Salmonella serovar Enteritidis infections in humans in our region.