2004: : Ixodes ricinus as a potential vector of Pasteurella for humans

1: Ann Agric Environ Med. 2004;11(2):319-22. Related Articles, Links


Studies on the occurrence of Gram-negative bacteria in ticks: Ixodes
ricinus as a potential vector of Pasteurella.

Stojek NM, Dutkiewicz J.

Department of Occupational Biohazards, Institute of Agricultural
Medicine, Jaczewskiego 2, 20-090 Lublin, Poland.
nina@xxxxxxxxxxxxxxxxxxx

A total of 372 Ixodes ricinus ticks (101 females, 122 males, and 149
nymphs) collected by flagging in 6 mixed woodlands of eastern Poland
were examined by culture for the presence of internal Gram-negative
bacteria other than Borrelia burgdorferi. Adult ticks were examined in
pools of 2 specimens each and nymphs were examined in pools of 3-5
specimens each. Ticks were disinfected in 70 % ethanol and homogenized
in 0.85% NaCl. The diluted homogenate was inoculated onto 3 kinds of
agar media: buffered charcoal yeast extract (BCYE-alpha) for isolation
of fastidious Gram-negative bacteria, eosin methylene blue agar (EMB)
for isolation of enterobacteria, and tryptic soya agar for isolation of
all other non-fastidious Gram-negative bacteria. The Gram-negative
isolates were identified with the API Systems 20E and NE microtests. A
total of 9 species of Gram-negative bacteria were identified, of which
the commonest were strains determined as Pasteurella
pneumotropica/haemolytica, which were isolated on BCYE-alpha agar from
ticks collected in all 6 examined woodlands. The total number of these
strains (49) exceeded the total number of all other strains of
Gram-negative bacteria recovered from ticks (30). Of the total number
of examined ticks, the minimum infection rate with Pasteurella
pneumotropica/haemolytica was highest in females (18.8%), and slightly
lower in males (12.3%) and nymphs (10%). Besides Pasteurella
pneumotropica/haemolytica, the following species of Gram-negative
bacteria were isolated from examined ticks: Pantoea agglomerans,
Serratia marcescens, Serratia plymuthica on EMB agar and Aeromonas
hydrophila, Burkholderia cepacia, Chromobacterium violaceum,
Pseudomonas aeruginosa, and Stenotrophomonas maltophilia on tryptic
soya agar. Minimal infection rates with these bacteria were low,
ranging from 0.7-5.9%. Of the isolated bacteria, Chromobacterium
violaceum, Pasteurella pneumotropica/haemolytica, Pseudomonas
aeruginosa, and Serratia marcescens are potentially pathogenic for man
and/or animals. In particular, the common occurrence of Pasteurella
pneumotropica/haemolytica in Ixodes ricinus ticks poses a potential
risk of pasteurellosis for humans and animals exposed to tick bites.

PMID: 15627343 [PubMed - indexed for MEDLINE]

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