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Letter
VanB-VanC1 Enterococcus
gallinarum, Italy
Caterina Mammina,*
Anna Maria Di Noto,† Antonella Costa,† and Antonino Nastasi‡
*Università degli Studi, Palermo, Italy; †Istituto Zooprofilattico Sperimentale
della Sicilia, Palermo, Italy; and ‡Università degli Studi, Florence,
Italy
Suggested
citation for this article
To the Editor: We report detecting a vanB determinant in
Enterococcus gallinarum in poultry in Italy. High-level vanA-mediated
glycopeptide resistance has been described for E. gallinarum and
E. casseliflavus (1–4), and vanB-mediated
vancomycin resistance has been frequently described for E. faecalis
and E. faecium. However, vanB-mediated resistance in isolates
of E. gallinarum has been described only in sporadic nosocomial
cases of infection or colonization (5,6).
In January 2005, a study of contamination by foodborne organisms in slaughtered
broiler carcasses was conducted in Sicily. To detect glycopeptide-resistant
enterococci (GRE), each carcass was placed in a bag with 100 mL sterile
buffered peptone water and shaken vigorously for 60 sec. After overnight
incubation at 37°C, 0.5 mL rinsate was added in duplicate to 5 mL
ethyl violet azide broth (Oxoid, Basingstoke, United Kingdom) with 4 mg/L
vancomycin. Broth cultures were further incubated at 37°C for 48 h,
and 0.1 mL aliquots were spread onto duplicate plates of VRE (commercial
denomination product, Oxoid) agar.
A vancomycin-resistant isolate of E. gallinarum was identified
in a carcass from a broiler farm in eastern Sicily. The biochemical tests
of API 20 Strep (bioMérieux, Marcy l'Etoile, France) and motility test
at 30°C were used to characterize the isolate at the species level.
The MICs of vancomycin and teicoplanin were 64 μg/mL and 1 μg/mL,
respectively. The isolate was subjected to a multiplex polymerase chain
reaction followed by an endonuclease cleavage of amplicons by MspI
(Invitrogen, Carlsbad, CA, USA) as previously described (7)
to detect van gene determinants; this process demonstrated a simultaneous
presence of vanC1 and vanB determinants.
E. gallinarum and the other motile enterococci are thought to
infrequently cause infection. However, the recent involvement of vanC1-vanA
E. gallinarum in person-to-person spread in a long-term-care facility
(8) and in an intensive care unit (2),
along with identification of vanC1-vanB isolates in some
patients treated with prolonged courses of glycopeptides (5,6),
suggests reassessment of their possible pathogenic role.
For the first time, 1 isolate of E. gallinarum has been found
harboring the vanB gene in poultry. Our findings confirm that E.
gallinarum can capture the genetic determinants of high-level glycopeptide
resistance, probably under selective pressure conditions that do not permit
survival of a host organism with constitutive low-level resistance (3).
Previous studies have demonstrated that E. gallinarum can transfer
these determinants to E. faecium by conjugation (2).
The role of food animals as reservoirs of GRE and the causes of their
persistently high prevalence in poultry carcasses in some European countries
are being investigated (9). Moreover, the public health
risk associated with consumer exposure to GRE when handling raw animal
foods is poorly understood. In Europe, the food chain is thought to be
the major source of GRE since avoparcin was used as a food additive for
animals until the European Union ban in 1997. Previous studies in Italy
showed that avoparcin withdrawal successfully reduced GRE contamination
of poultry meat products (10). However, our finding,
7 years after the European Union ban, highlights that resistance genotypes
in motile enterococci should be closely monitored (11).
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Suggested citation
for this article:
Mammina C, Di Noto
AM, Costa A, Nastasi A. VanB-vanC1 Enterococcus gallinarum,
Italy [letter]. Emerg Infect Dis [serial on the Internet]. 2005 Sep [date
cited]. Available from http://www.cdc.gov/ncidod/EID/vol11no09/05-0282.htm
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