A European outbreak of Salmonella enterica serotype Typhimurium definitive phage type 204b in 2000

OBJECTIVE

To describe the clinical, epidemiologic and microbiological features of a large outbreak of infection with a multiresistant Salmonella enterica serotype Typhimurium definitive type DT204b infection involving at least 392 people in five European countries.

METHODS

Icelandic public-health doctors responded to a report on an Internet news site of an outbreak of infection with a multiresistant strain of Typhimurium DT104 in England by contacting the Public Health Laboratory Service (PHLS) Communicable Disease Surveillance Centre (CDSC). An international alert was sent out through Enter-net. All strains from England & Wales, The Netherlands, Scotland and Germany, and 17 of the outbreak isolates from Iceland, were phage-typed, screened for antimicrobial resistance, and subjected to molecular typing. Hypothesis-generating interviews were conducted, followed by case-control studies performed in Iceland and England.

RESULTS

Isolates from cases in Iceland, England and Wales, The Netherlands, Scotland and Germany were identified as Typhimurium DT204b. The antimicrobial resistance pattern was ACGNeKSSuTTmNxCpL. All strains tested displayed an identical plasmid profile. Strains from five cases in England & Wales and five cases in Iceland possessed identical pulsed-field profiles. Although a common source was suspected, only Iceland implicated imported lettuce as a vehicle, with an analytic epidemiologic study (OR = 40.8; P = 0.005; 95% CI 2.7-3175).

CONCLUSION

The identification of international outbreaks, necessary for investigation and control, can be facilitated by standardized phage-typing techniques, the electronic transfer of molecular typing patterns, formal and informal links established through international surveillance networks, and the early reporting of national outbreaks to such networks.

Urine D-arabinitol/L-arabinitol ratio in diagnosis of invasive candidiasis in newborn infants

Infants treated in neonatal intensive care units suffer an increased risk for invasive candidiasis, but the diagnosis is sometimes difficult. D-arabinitol is a metabolite of most pathogenic Candida species. An elevated urine D-arabinitol/L-arabinitol (DA/LA) ratio is a sensitive sign of invasive candidiasis in children with cancer, but the method has not been previously evaluated for newborn infants. We therefore enrolled 117 infants in a neonatal intensive care unit, and 411 urine samples were obtained on filter paper. The DA/LA ratio was measured by gas chromatography-mass spectrometry. For 81 infants with no suspicion of superficial or invasive candidiasis, the urine DA/LA ratio was 2.7 +/- 0.7 (mean +/- standard deviation [SD]). The upper cutoff level was set at 4.8 (mean plus 3 SD). Of 22 infants with mucocutaneous candidiasis and not given systemic antifungal treatment, two had elevated DA/LA ratios, which normalized after removal of intravascular catheters. Eight other infants were given empiric antifungal treatment but had negative cultures; five of these had repeatedly elevated DA/LA ratios. Six infants with culture-positive invasive candidiasis all had one or more samples with elevated ratios. For seven infants, three with suspected and four with confirmed invasive candidiasis (for which follow-up samples were available), ratios normalized during antifungal treatment. In conclusion, urine DA/LA ratio determination is a rapid test and can be used for newborns. It is possibly more sensitive than fungal blood cultures in the diagnosis of invasive candidiasis and can also be used for monitoring the effect of antifungal treatment.