Role of gram-negative anaerobic cocci belonging to the genus Veillonella in infectious complications in cancer patients

We studied capabilities of the Bruker Microflex MALDI-TOF device for species identification of anaerobic gram-negative cocci isolated from clinical specimens of cancer patients. Seventy clinical isolates of Veillonella spp. and one Acidaminococcus spp were analyzed. All isolates were identified to the species level with a scores greater than 1.9. The most common species were V. parvula (37 strains), followed by V. dispar (16), V. atypica (16) and V. denticariosi (1). Susceptibilities of the isolates were determined by the E-test methodology. All Veillonella isolates were susceptible to imipenem, whereas high resistance rates were observed for penicillin G, amoxicillin/clavulanate and metronidazole. The proportion of resistant isolates of V. parvula, V. dispar and V. atypica to penicillin was 86 %, 85 % and 100 %, respectively. The resistance to amoxicillin/clavulanate was observed in 28.6 % of V. parvula isolates, 23.1 % of V. dispar isolates and in 6.7 % of V. atypica isolates. Resistance to metronidazole (MIC ≥ 8 µg/ml) of V. parvula, V. dispar and V. atypica was 88.6 %, 53.8 % and 40 %, respectively.