Primary antibiotic resistance and associated mechanisms in Helicobacter pylori isolates from Senegalese patients

Abstract

BackgroundAntibiotic combination therapy for Helicobacter pylori eradication must be adapted to local resistance patterns, but the epidemiology of H. pylori resistance to antibiotics is poorly documented in Africa. The aim was to determine the antibiotic resistance rates, as well as the associated molecular mechanisms, of strains isolated in Dakar, Senegal.MethodsOne hundred and eight H. pylori strains were isolated between 2007 and 2009 from 108 patients presenting with upper abdominal pain to the Gastroenterology Department of Le Dantec Hospital. Antimicrobial susceptibility testing was performed for amoxicillin, clarithromycin, metronidazole, levofloxacin and tetracyclin using the E-test method. Mutations in the 23S rRNA gene of clarithromycin-resistant strains and in gyrA and gyrB of levofloxacin-resistant strains were investigated.ResultsIsolates were characterized by no resistance to amoxicillin (0%), tetracycline (0%), and very low rate of resistance to clarithromycin (1%), but a high rate of resistance to metronidazole (85%). The clarithromycin-resistant strain displayed the A2143G mutation. A worrying rate of levofloxacin resistance was detected (15%). N87I and D91N were the most common mutations in the quinolone-resistance-determining region of gyrA.ConclusionsThe first-line empirical regimen for H. pylori eradication in Senegal should include clarithromycin. Increasing rates of fluoroquinolone resistance detected should discourage the use of levofloxacin-containing regimens without prior antimicrobial susceptibility testing.

Antibiotic treatment forHelicobacter pylori: Is the end coming?

“…In one study, clarithromycin resistance was reported in 47.5% of patients with dyspepsia in Turkey [41] . In sharp contrast to other Asian countries, no resistance to clarithromycin has been reported in Malaysia [42] and the prevalence of resistance to clarithromycin in Gambia and Senegal also remains very low [43,44] . Resistance to clarithromycin has also risen by > 20% in Southern Europe, although in Northern Europe the resistance rate is less than 10% [45] compared to 1.5% in a random adult Swedish population [46] and 7.5% in central Germany [47] .…”

“…In Vietnam, the resistance rate was 69.9% among 103 strains [40] . Unlike the clarithromycin resistance rate, there was a high prevalence of resistance to metronidazole (75.5%) in Malaysia [42] , a 76.8% rate in Iran [54] and a high resistance rate in Africa [43,44] . Another study showed that 80% of strains in Mexico were resistant to metronidazole [55] .…”

“…A study by Mégraud [62] of more than 2000 patients with H. pylori infection showed resistance rates of 14.1% for levofloxacin, with significantly higher fluoroquinolone resistance in Western/Southern Europe than in Northern Europe [62] . O'Connor et al [63] reported that 11.7% of patients had strains resistant to levofloxacin in Ireland and there was a 29.1% resistance rate in 2011 in Germany [64] , 15% in Senegal [44] and 23% in Brazil [65] .…”

Molecular detection of H. pylori antibiotic‐resistant genes and molecular docking analysis

“…Matsuzaki et al found amino acid 87 and 91 sites were located in the N-terminal region of GyrA protein combined with DNA. Seck et al also found no gyrA mutation in some LVX-resistant strains, 34 suggesting other resistance-related mechanisms such as efflux pump, 35 membrane permeability, autophagy, globular transformation, and even new resistant genes. 31,32 Some studies showed that sitafloxacin and garenoxacin may overcome the antibiotic resistance of H. pylori with gyrA mutation.…”

CTX-M-15-producing Morganella morganii from Hôpital Principal de Dakar, Senegal

“…However, while the dissemination and high prevalence of antibiotic resistance in Gram-negative bacilli has been described worldwide and could be associated with international travel and tourism 5, few studies have described the prevalence and mechanism of antibiotic resistance in Enterobacteriaceae from northern Africa, especially Senegal 3. Indeed, the few studies conducted in this region were on Enterobacteriaceae species including Shigella flexneri and Salmonella enterica , which are not classified as dominant nosocomial pathogens 6,7. In this region, we have recently described the emergence of clinical multidrug-resistant Gram-negative bacteria, especially Acinetobacter baumannii , resistant to all β-lactams including the carbapenems 8, which has never been reported before in Senegal.…”