ABSTRACT
The present study aimed to improve the rate of detection of blood-borne microbes by using PCRs with pan-bacterial and Candida specificity. Seventeen per cent of the blood samples (n=178) collected from 107 febrile patients with haematological malignancies were positive using standard culture (BacT/Alert system). Candida PCR was positive in 12 patients, only one of whom scored culture-positive. Bacterial PCR using fresh blood samples was often negative, but the detection rate increased when the blood was pre-incubated for 2 days. These data indicate that PCR assays might be a complement for the detection of blood-borne opportunists in immunocompromised haematology patients.
Subject(s)
Bacteremia , Blood/microbiology , Candida/isolation & purification , Fungemia , Gram-Negative Bacteria/isolation & purification , Gram-Positive Bacteria/isolation & purification , Hematologic Neoplasms/complications , Polymerase Chain Reaction/methods , Bacteremia/epidemiology , Bacteremia/microbiology , Candida/classification , Candida/genetics , Candida albicans/genetics , Candida albicans/isolation & purification , Candida glabrata/genetics , Candida glabrata/isolation & purification , Candidiasis/microbiology , Culture Media , DNA, Bacterial/analysis , DNA, Fungal/analysis , Fever , Fungemia/epidemiology , Fungemia/microbiology , Gram-Negative Bacteria/genetics , Gram-Positive Bacteria/genetics , Humans , Immunocompromised Host , Neutropenia , Opportunistic Infections/epidemiology , Opportunistic Infections/microbiologyABSTRACT
This is the first report of a major foodborne outbreak of enterohaemorrhagic Escherichia coli (EHEC) in Sweden. It occurred among the nursing staff at a children's hospital with approximately 1600 employees. Contaminated lettuce was the most likely source of infection. Nine persons were culture-positive for Escherichia coli (E. coli) O157 and verocytotoxin-positive by PCR and a further two were verocytotoxin-positive by PCR only. All 11 EHEC-positive individuals had attended a party for approximately 250 staff members, which was held at the hospital. In a questionnaire 37 persons stated that they had symptoms consistent with EHEC infection during the weeks after the party. There was no evidence of secondary transmission from staff to patients. The value of PCR as a sensitive and fast method for diagnosis is discussed in this paper. Pulsed-field gel electrophoresis (PFGE) was used to ascertain that staff members were infected by the same clone, and that two patients with E. coli O157 infection were not.
Subject(s)
Disease Outbreaks/statistics & numerical data , Electrophoresis, Gel, Pulsed-Field/methods , Escherichia coli Infections/diagnosis , Escherichia coli Infections/epidemiology , Escherichia coli O157 , Foodborne Diseases/diagnosis , Occupational Diseases/diagnosis , Occupational Diseases/epidemiology , Personnel, Hospital , Polymerase Chain Reaction/methods , DNA, Bacterial/analysis , DNA, Bacterial/genetics , Disease Outbreaks/prevention & control , Electrophoresis, Gel, Pulsed-Field/standards , Epidemiologic Methods , Escherichia coli Infections/microbiology , Escherichia coli Infections/prevention & control , Escherichia coli Infections/transmission , Escherichia coli O157/classification , Escherichia coli O157/genetics , Feces/microbiology , Food Microbiology , Foodborne Diseases/epidemiology , Foodborne Diseases/microbiology , Hospitals, Pediatric , Humans , Infection Control/methods , Lactuca/microbiology , Mass Screening/methods , Occupational Diseases/microbiology , Occupational Diseases/prevention & control , Occupational Health , Personnel, Hospital/statistics & numerical data , Polymerase Chain Reaction/standards , Sensitivity and Specificity , Serotyping , Shiga Toxin 1/genetics , Shiga Toxin 2/genetics , Sweden/epidemiology , Time FactorsABSTRACT
The aims of the present investigation were to evaluate the microbiological diagnostic procedures, especially polymerase chain reaction (PCR) versus culture and seroagglutination, in relation to the clinical features of enterohaemorrhagic Escherichia coli (EHEC) infection and to study the status of EHEC in the western part of Sweden. During 1997 and 1998, stool specimens from 3,948 patients were analysed by PCR for the presence of EHEC with verotoxin (VT)1- and/or VT2-producing DNA sequences. The stool specimens were also cultured for Escherichia coli O157:H7, Salmonella, Campylobacter, Shigella and Yersinia. Fifty-five patients were positive by PCR. Thirty-nine patients were positive for EHEC by PCR and culture. Of these, 29 were infected with EHEC serogroup O157:H7 strains. All EHEC isolates were analysed by pulsed-field gel electrophoresis (PFGE); 17 different clones were identified. Studies on the duration of the presence of EHEC in the gut showed that EHEC often disappears rather quickly, i.e. within 2 weeks. In one patient, however, EHEC remained for several months. In conclusion, PCR, rather than culture and agglutination, should be the method of choice for microbiological diagnosis of EHEC infection. PCR is more sensitive than culture for detecting EHEC in the gut.