Abstract
The presence of amino acid changes in GyrA, GyrB, ParC, ParE, and in a proposed chromosomal chloramphenicol acetyl transferase (CAT), as well as mutations at 23S rRNA, were established by PCR and sequencing in 38 B. bacilliformis clinical isolates from four different areas in Peru. Eighteen out of 24 (75%) isolates showing ciprofloxacin resistance for both disk-diffusion and e-test presented amino acid substitutions in GyrA (G89C, six isolates, A91V, 1 isolate) GyrB (S474F, 10 isolates) or both (GyrA D95N and GyrB S474F, one isolate). Two out of 14 susceptible isolates presented amino acid substitutions at GyrB (S474F) or a double substitution GyrA D95N and GyrB S474F. Of note, ciprofloxacin-resistant isolates were recovered in the four areas studied. No amino acid change was observed at ParC or ParE. Only one isolate showed chloramphenicol resistance, but no alteration was present in either 23S rRNA or CAT. B. bacilliformis resistant to quinolones are extended throughout Peru, with amino acid substitutions at GyrA or GyrB as the main, albeit not exclusive, cause. B. bacilliformis seems to have an apparent facility to develop mutations on GyrB outside the classical positions 91, 95 of GyrA and 85, 88 of ParC.
Highlights
Bartonella bacilliformis is the etiological agent of Carrion’s disease, which is a biphasic illness, accounting for an acute, the so-called “Oroya fever”, and a chronic phase, namely “Peruvian Wart” [1]
The results showed that the quinolone resistance determining regions (QRDR) sequences belonging to 27 (71.1%) isolates were identical to those of Cond044 or Peru18
No differences were detected with the sequenced region of the 23S rRNA as it was identical in all the B. bacilliformis genomes
Summary
Bartonella bacilliformis is the etiological agent of Carrion’s disease, which is a biphasic illness, accounting for an acute, the so-called “Oroya fever”, and a chronic phase, namely “Peruvian Wart” [1]. Patterns have been described in B. bacilliformis [4], with the presence of two subspecies being proposed [5]. It has been proposed that isolates belonging to sequence type (STs) 1 to 7, 9 to 11 and 13 and 14 be classified within subsp. 1, with the strain KC583 being the representative strain [4,5] and STs 8 and 12 be classified within subsp. 2, with strain Ver as the representative strain [4,5]. Loparev et al proposed that B. bacilliformis subsp. 2 might be another species closely related to B. bacilliformis [6]. While the species or subspecies status of B. bacilliformis belonging to STs 8 and 12 remains to be firmly established, the subdivision subsp. While the species or subspecies status of B. bacilliformis belonging to STs 8 and 12 remains to be firmly established, the subdivision subsp. 1/subsp. 2 is followed in the text in order to classify the results obtained
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