Antibiotic resistance among Helicobacter pylori clinical isolates in Lima, Peru

Figures & data

Table 1 Quality control ranges for ATCC 43504 and 25922

Antibiotic	Helicobacter pylori strain 43504 QC ranges, mg/L	Escherichia coli strain 25922 QC ranges, mg/L
Tetracycline	0.12–1	–
Amoxicillin	0.015–0.12	–
Metronidazole	64–256	–
Clarithromycin	0.015–0.12	–
Levofloxacin	–	0.008–0.06
Rifampicin	–	4–16

Note: E-test strip quality control ranges for antibiotics used in this study.

Abbreviation: QC, quality control.

Table 2 Primary antibiotic resistance of clinical isolates from Lima, Peru

	Amoxicillin	Clarithromycin	Tetracycline	Levofloxacin	Metronidazole	Rifampicin
Resistance cutoff (mg/L)	>0.125	≥0.5	>1	>1	>8	>1
Isolates susceptible (%)	51/76 (67.1)	49/76 (64.5)	73/76 (96.1)	35/76 (46.1)	29/76 (38.2)	41/76 (53.9)
Isolates resistant (%)	25/76 (32.9)	27/76 (35.5)*	3/76 (3.9)	41/76 (53.9)	47/76 (61.8)	35/76 (46.1)
MIC50 (mg/L)	0.0555	0.094	3	0.048	256	0.875
MIC90 (mg/L)	256	256	32	0.125	256	32
MIC range (mg/L)	0–256	0–256	0.25–32	0.032–32	0.25–256	0–256

Notes: Results of MIC testing using E-test strips from bioMérieux. Susceptibility and resistance were determined using EUCAST standards.

* Five isolates had a 0.5-µg/mL MIC for clarithromycin, which falls between the susceptible and resistant cutoffs for clarithromycin. For the purposes of this analysis, they were considered resistant.

Abbreviation: MIC, minimum inhibitory concentration.

Table 3 Primary resistance to >1 antibiotic among clinical isolates

	No. resistance	1	2	3+	Resistant to clarithromycin and amoxicillin
Number of isolates, n/N (%)	2/76 (2.6)	21/76 (27.6)	22/76 (28.9)	31/76 (40.8)	8/76 (10.5)

Notes: Nearly all isolates were resistant to at least one antibiotic, and 70% were resistant to two or more. Eight of 76 isolates were resistant to both clarithromycin and amoxicillin, which are both used in the triple therapy.

Table 4 Reported primary antibiotic resistance among Helicobacter pylori isolates from Peru using EUCAST guidelines

	Amoxicillin, %	Clarithromycin, %*	Tetracycline, %	Levofloxacin, %	Metronidazole, %	Rifampicin, %
Vasquez et al^Citation16	N/A	38.9 (7/18)	0 (0/5)	N/A	27.8 (5/18)	N/A
Berg et al^Citation17	N/A	4.2 (1/24)	N/A	N/A	63.6 (49/77)	N/A
Mochizuki Tamayo et al^Citation15	N/A	N/A	N/A	36.8 (35/95)	N/A	N/A
Totals, including present study	32.9 (25/76)	29.7 (34/118)	3.7 (3/81)	44.4 (76/171)	59.1 (101/171)	46.1 (35/76)

Notes: Meta-analysis of primary antibiotic resistance among isolates from all studies in Peru.

* Six isolates had a clarithromycin MIC of 0.5 mg/L. For the purposes of this meta-analysis, we counted them as resistant.

Abbreviations: MIC, minimum inhibitory concentration; N/A, not applicable.

Mochizuki TamayoHNoriega AldaveAPAntimicrobial susceptibility of helicobacter pylori to levofloxacin determined in a miniwell format and disk diffusion tests using egg yolk agarRev Gastroenterol Peru2011313224229 Spanish22086316

 PubMedGoogle Scholar

VasquezAValdezYGilmanRHMetronidazole and clarithromycin resistance in Helicobacter pylori determined by measuring MICs of antimicrobial agents in color indicator egg yolk agar in a miniwell formatAm Soc Microbiol199634512321234

 Google Scholar

PilcoPPayetECáceresEGastric cancer in LimaRev Gastroenterol Peru2006264377385 Available from: http://europepmc.org/abstract/med/17211488Accessed September 25, 2015 Spanish17211488

 PubMedGoogle Scholar