Genetic diversity and clonal characteristics of ciprofloxacin-resistant Campylobacter jejuni isolated from Chilean patients with gastroenteritis.

Campylobacter jejuni is a major cause of acute gastroenteritis worldwide. However, it has also been associated with other diseases such as bacteremia and with several post-infection sequelae. Although campylobacteriosis is usually a self-limited infection, antibiotics are indicated for severe and chronic conditions. Unfortunately, several industrialised nations have reported a substantial increase in antibiotic resistance of C. jejuni. However, there is still a lack of knowledge about the epidemiology of resistance developed by this pathogen in the developing world. For this reason, our objective was to determine the resistance of clinical C. jejuni strains to ciprofloxacin and erythromycin in Chile and their associated genotypes. Fifty C. jejuni isolates recovered from fecal samples of people with acute gastroenteritis, in central and southern Chile between 2006 and 2015, were analysed. Resistance to erythromycin and ciprofloxacin was assessed by disk diffusion and agar dilution methods. Furthermore, these strains were genotyped by Multilocus Sequence Typing (MLST). Only one of the isolates was resistant to erythromycin. However, 48% of them were resistant to ciprofloxacin. The minimal inhibitory concentration of these ciprofloxacin-resistant isolates was in the range between 4 and 32 µg/ml. Moreover, MLST analyses showed that most ciprofloxacin-resistant strains were grouped into three dominant clonal complexes (ST-21, ST-48 and ST-353), while the unique strain resistant to both antibiotics belonged to the ST-45 complex. Our results evidence a high ciprofloxacin resistance and suggest that there is a dissemination of resistant clonal lineages responsible for cases of campylobacteriosis in Chile. Further studies should elucidate the origin of these resistant genotypes.

Ciprofloxacin resistance in uropathogenic Escherichia coli isolates causing community-acquired urinary infections in Brasília, Brazil.

OBJECTIVES: Considering the global concern of ciprofloxacin resistance, the aim of this study was to evaluate the characteristics of ciprofloxacin-resistant (CIP-R) Escherichia coli isolated from patients with community-acquired urinary tract infections (UTIs) in Brasília, Brazil. METHODS: CIP-R E. coli isolated from different outpatients between July 2013 and April 2014 in a tertiary hospital were analysed for antibiotic resistance profile, phylotype, uropathogenic E. coli (UPEC) virulence genes, clonal relationship by enterobacterial repetitive intergenic consensus PCR (ERIC-PCR), and multilocus sequence typing (MLST). RESULTS: Among the 324 UPEC analysed, 263 (81.2%) were ciprofloxacin-sensitive and 61 (18.8%) were CIP-R. Antibiogram analysis of the 61 CIP-R strains showed that 45 (73.8%) were also multidrug-resistant. The most prevalent phylogroups were A and B2 (26/61 and 18/61, respectively). traT (53/61) and aer-traT (24/61) were the most common gene and genotype observed. Dendrogram analysis found that multidrug resistance and virulence genes were distributed among CIP-R strains independently of clonality and phylogroup. Six ERIC clusters (strains sharing ≥85% genetic similarity) were observed. MLST analysis of all strains of each cluster identified sequence types (STs) associated with worldwide antimicrobial resistance dissemination, including B2-ST131 and ST410, as well as STs not yet associated with antimicrobial resistance propagation, such as ST1725 and ST179. CONCLUSIONS: These results demonstrate that ciprofloxacin resistance dissemination by UPEC causing community-acquired UTIs was associated with multidrug resistance and was promoted by pandemic and non-pandemic STs, a concerning scenario for the local population.

Molecular basis of high-level ciprofloxacin resistance in Neisseria gonorrhoeae strains from Shandong Province, China.

In the study, the ciprofloxacin resistance rate was 100%. High-level ciprofloxacin resistance rate was 63.55%. Sixteen different mutation patterns involved in the formation of ciprofloxacin resistance were identified. The most prevalent were patterns P7 (25.2%), P8 (15.0%), P9 (11.2%), P1 (10.3%), and P5 (10.3%). All of the 107 NG isolates analyzed for mutations in the study have demonstrated a change of Ser-91 → Phe in the gyrA gene, and all except one have demonstrated a change in position 95 of the amino acid sequence. All of the 68 high-level QRNG isolates had double mutations in gyrA gene combined with a single or two mutations in parC gene. It is most important that a new mutation site of Ile-97 → Met in gyrA and a new mutation of Leu-106 → Ile in parC were found in the study, both leading to high-level ciprofloxacin resistance (MIC values, 8 µg/mL, 32 µg/mL, respectively). Therefore, we confim that gyrA mutations are necessary for the fluoroquinolone resistance phenotype and parC mutations are correlated intimately with high-level fluoroquinolone resistance. In China fluoroquinolone resistance in Neisseria gonorrhoeae strains is very serious and the new mutation sites in the fluoroquinolone resistance-determining regions emerge more and more quickly. Hence, in China fluoroquinolones, which are used to treat gonorrhoea presently, should be substituted by a new antibiotics.

Molecular basis of high-level ciprofloxacin resistance in Neisseria gonorrhoeae strains from Shandong Province, China

In the study, the ciprofloxacin resistance rate was 100%. High-level ciprofloxacin resistance rate was 63.55%. Sixteen different mutation patterns involved in the formation of ciprofloxacin resistance were identified. The most prevalent were patterns P7 (25.2%), P8 (15.0%), P9 (11.2%), P1 (10.3%), and P5 (10.3%). All of the 107 NG isolates analyzed for mutations in the study have demonstrated a change of Ser-91 → Phe in the gyrA gene, and all except one have demonstrated a change in position 95 of the amino acid sequence. All of the 68 high-level QRNG isolates had double mutations in gyrA gene combined with a single or two mutations in parC gene. It is most important that a new mutation site of Ile-97 → Met in gyrA and a new mutation of Leu-106 → Ile in parC were found in the study, both leading to high-level ciprofloxacin resistance (MIC values, 8 µg/mL, 32 µg/mL, respectively). Therefore, we confim that gyrA mutations are necessary for the fluoroquinolone resistance phenotype and parC mutations are correlated intimately with high-level fluoroquinolone resistance. In China fluoroquinolone resistance in Neisseria gonorrhoeae strains is very serious and the new mutation sites in the fluoroquinolone resistance-determining regions emerge more and more quickly. Hence, in China fluoroquinolones, which are used to treat gonorrhoea presently, should be substituted by a new antibiotics.