Prevalence of Genetic Determinants and Phenotypic Resistance to Ciprofloxacin in Campylobacter jejuni from Lithuania

Abstract

Recently, the number of reports on isolation of ciprofloxacin resistant Campylobacter jejuni has increased worldwide. The aim of this study was to determine the prevalence of resistance to ciprofloxacin and its genetic determinants among C. jejuni isolated from humans (n = 100), poultry products (n = 96) and wild birds (n = 96) in Lithuania. 91.4% of the C. jejuni isolates were phenotypically resistant to ciprofloxacin. DNA sequence analyses of the gyrA gene from 292 isolates revealed that a change in amino acid sequence, Thr86Ile, was the main substition conferring resistance to ciprofloxacin. This change was significantly associated with isolates from poultry products (P < 0.05) and humans (P < 0.05). A total of 26.7% of C. jejuni isolates from human (n = 47), poultry products (n = 30) and wild bird (n = 1), had a mutation from Ser at position 22, and six had an additional mutation from Ala at position 39. Eight isolates from poultry and two isolates from human, corresponding to 67.0% of isolates with MICs ≥128 μg/ml, showed missense mutations Thr86Ile (ACA → ATA) and Ser22Gly (AGT → GGT) together, whereas isolates without these mutations showed lower MIC values (from 4 to 64 μg/ml). Two hundred forty-five C. jejuni isolates showed one or more silent mutations, and 32.4% of examined isolates possessed six silent mutations. In addition to the ciprofloxacin resistant isolates harboring only Thr86Ile point mutation (110 isolates), the current study identified resistant isolates (n = 101) harboring additional point mutations (Ser22Gly, Ala39Ser, Arg48Lys, Thr85Ala Ala122Ser, Glu136Asp, Vall49Ile), and strains (n = 57) having only Glu136Asp point mutation. The study highlight the potential public health problem with elevated ciprofloxacin resistance in Campylobacters from poultry meat, wild birds and humans, and the need for extensive surveillance enabling to follow changes of antimicrobial resistance development in this species.

Antimicrobial susceptibility of clinical isolates of Campylobacter jejuni from New South Wales, Australia

“…Resistance to fluoroquinolones in Campylobacter spp., while associated with many single amino acid substitutions is predominantly associated with a nucleotide mutation in the gyrA gene which leads to a T86I substitution in the expressed protein [20,34]. In the current study, this substitution was detected in most isolates resistant to ciprofloxacin.…”

Characterization and Phylogenetic Analysis of Campylobacter Species Isolated from Paediatric Stool and Water Samples in the Northwest Province, South Africa

“…However, some bacteria have developed resistance to this set of antibiotics by substituting amino acids at the quinolone resistance-determining region (QRDR) of the topoisomerase [3]. In Campylobacter , resistance to quinolones is primarily mediated by a single point mutation in the QRDR of the gyrA gene at codon 86 (that is, an alteration of the nucleotide from ACA to ATA), leading to isoleucine substitution for threonine [90,91]. Although there are different types of amino acid substitutions, the most frequently observed is the C 257 T mutation in the gyrA gene which leads to Thr86Ile substitution in the gyrase and confers a high level of resistance to this class of antibiotics [90].…”

“…In Campylobacter , resistance to quinolones is primarily mediated by a single point mutation in the QRDR of the gyrA gene at codon 86 (that is, an alteration of the nucleotide from ACA to ATA), leading to isoleucine substitution for threonine [90,91]. Although there are different types of amino acid substitutions, the most frequently observed is the C 257 T mutation in the gyrA gene which leads to Thr86Ile substitution in the gyrase and confers a high level of resistance to this class of antibiotics [90]. In the current study, 18.4% of the human and 25% of the water Campylobacter isolates harboured the gryA gene.…”

“…Previous studies have reported a similarly high occurrence of the gryA gene in C. jejuni strains. For example, a study conducted in Europe reported that over 41% of C. jejuni isolated from humans, poultry products, water and wild bird carcasses expressed the gyrA gene [90]. Pere-boto et al also reported that the gyrA gene is the most prevalent resistance gene in clinical isolates collected from 10 different provinces in Spain, and was expressed mostly in C. jejuni isolates that exhibited high ciprofloxacin MIC [14].…”

“…Pere-boto et al also reported that the gyrA gene is the most prevalent resistance gene in clinical isolates collected from 10 different provinces in Spain, and was expressed mostly in C. jejuni isolates that exhibited high ciprofloxacin MIC [14]. Previous studies have reported that most ciprofloxacin-resistant Campylobacter spp., especially C. jejuni strains, express the Thr86Ile amino acid substitution in the QRDR of gyrA [40,90,92]. The CDC, in 2013, reported that fluoroquinolone resistance among Campylobacter strains comes with a heavy economic burden because infections caused by fluoroquinolone-resistant strains stay longer and can in most cases lead to death [68].…”