Neonatal sepsis due to NDM-1 and VIM-2 co-producing Pseudomonas aeruginosa in Morocco.

BACKGROUND: Carbapenem-resistant Pseudomonas aeruginosa are being increasingly described worldwide. Here, we investigated the molecular mechanisms underlying carbapenem resistance in an extremely drug-resistant P. aeruginosa isolate from a neonatal intensive care unit in Morocco. MATERIALS AND METHODS: P. aeruginosa strain O82J1 was identified using MALDI-TOF-MS. Carba NP, immunochromatographic assay NG Carba5 and antimicrobial susceptibility testing using disc diffusion and microbroth were performed. Whole-genome sequencing using the Illumina and MinION technologies and different software packages available at the Center of Genomic Epidemiology were used to predict the resistome, sequence type and plasmid types. RESULTS: P. aeruginosa O82J1 co-expressed two metallo-ß-lactamases, blaNDM-1 and blaVIM-2, and was susceptible to colistin and apramycin only. It belonged to ST773 that is frequently reported worldwide as a high-risk P. aeruginosa clone. The blaVIM-2 gene was integron-borne on a IncP-2 465-kb plasmid, whereas the blaNDM-1 gene was chromosomally encoded and embedded in an integrative conjugative element, probably at the origin of its acquisition. A total of 23 antimicrobial resistance genes were detected including a blaPER-1 ESBL gene, and an 16S-rRNA methyltransferase gene rmtB. CONCLUSIONS: The isolation of XDR P. aeruginosa isolates expressing several carbapenemases in a neonatal intensive care unit is of great concern due to the reduced treatment options, relying only on colistin, but not recommended in neonates, and apramycin, not yet approved for human therapy. Concerns were further elevated due to the resistance to cefiderocol and ATM/AVI, two novel and last-resort antibiotics recommended to treat infections caused by Gram-negative bacteria, particularly XDR P. aeruginosa in adults.

Systematic Review and Meta-analysis of Histological Gastric Biopsy Aspects According to the Updated Sydney System in Children.

OBJECTIVES: A descriptive and comparative study of gastric histological aspects according to the updated Sydney classification (USC), obtained from Helicobacter pylori-positive versus H pylori-negative children referred for upper gastrointestinal endoscopy. METHODS: The Prisma method was used to perform a systematic review and meta-analysis. Selection criteria were based on following key words USC, H pylori, children, endoscopy, or biopsy. Publication biases were assessed according to the Newcastle-Ottawa Scale, and a meta-regression analysis was done. The study was registered on the PROSPERO platform. RESULTS: Between 1994 and 2017, 1238 references were found; 97 studies were retained for the systematic review with a total number of 25,867 children; 75 studies were selected for the meta-analysis concerning 5990 H pylori-infected and 17,782 uninfected children.H pylori-positive versus H pylori-negative children, according to the USC, showed significantly higher relative risk for gastric antral and corpus chronic inflammation, presence of neutrophils, and of lymphoid follicles, and gastric mucosa atrophy, whereas, intestinal metaplasia showed a significantly higher RR only in antral biopsies. The meta-regression analysis showed that H pylori-positive versus H pylori-negative children had significantly higher risk only for corpus activity according to age, recurrent abdominal pain, and geographical area of low H pylori prevalence. CONCLUSIONS: H pylori infection in children was associated with higher relative risk for gastric antral and corpus chronic inflammation, presence of neutrophils, lymphoid follicles, and rare gastric mucosa atrophy, whereas, rare intestinal metaplasia was only significantly higher in the antral area.

Characteristics of Helicobacter pylori strains isolated from Mauritanian patients.

BACKGROUND: Helicobacter pylori (H pylori) is responsible for various diseases including cancer It co-evolved with humans, and human migrations shaped the expansion and the diversity of strains around the world. The risk of developing a disease depends on virulence factors, mainly the cytotoxin-associated gene A protein (CagA). The aim of this study was to determine the cagA status in H pylori strains from Mauritanian patients and to search for a relationship with endoscopic and histologic findings. MATERIAL AND METHODS: H pylori was searched in gastric biopsies taken during endoscopy in patients with gastro-duodenal symptoms. RT-PCR was used for the diagnosis and resistance to clarithromycin. The cagA status was determined with PCR and the EPIYA-cagA polymorphism with sequencing. RESULTS: At all, 76/78 (97.4%) biopsies were positive. The rate of clarithromycin resistance was 4/76 (5.26%) due to the A2143G mutation, with a mixed population in 2 cases. The cagA gene was present in 23/76 (30.26%) biopsies, and the EPIYA motif was ABC in 21 (91.3%). High bacterial load and inflammation were significantly associated with cagA-positive status (P < .01). Phylogenetic analysis of the glmM and hspA genes highlighted a mixture of African and European genes in strains of H pylori isolated from patients of Moor origin. CONCLUSION: We report a high prevalence of H pylori infection in Mauritanian patients, a low rate of clarithromycin resistance (5.26%) and high bacterial load and inflammation associated with cagA-positive status. The phylogenetic analysis highlights the mix of different populations leading to the Moor ethnicity.

Risk Factors for Infant Colonization by Hypervirulent CC17 Group B Streptococcus: Toward the Understanding of Late-onset Disease.

BACKGROUND: In infants, the mode of acquisition of CC17 group B Streptococcus (GBS), the hypervirulent clone responsible for late-onset disease (LOD), remains elusive. METHODS: In a prospective multicenter study in France, we evaluated GBS colonization in mother-baby pairs with 2 months of follow-up between 2012 and 2015. Criteria included positivity for GBS colonization at antenatal screening or at delivery. Maternal vaginal samples and infant oral cavity and stool samples were analyzed at delivery, 21 ± 7 days (D21), and 60 ± 7 days (D60) post-delivery. RESULTS: A total of 890 mother-baby pairs were analyzed. GBS colonized 7%, 21%, and 23% of the infants at birth, D21, and D60, respectively, of which 10%, 11%, and 13% were identified as CC17 GBS. Concordance between maternal and infant GBS type was 96%. At D21, the main risk factors for infant colonization by GBS were simultaneous maternal colonization of the vagina (odds ratio [OR], 4.50; 95% confidence interval [CI], 1.69-15.61) and breast milk (OR, 7.93; 95% CI, 3.81-17.14). Importantly, 38% (95% CI, 23%-56%) of infants colonized by CC17 GBS appeared colonized for the first time at D60 vs 18% (95% CI, 14%-24%; P < .049) of infants colonized by non-CC17 GBS. Multivariate analysis showed a higher risk for de novo infant colonization by CC17 at D60 than by other GBS (OR, 2.45; 95% CI, 1.02-5.88). CONCLUSIONS: The high incidence of CC17 GBS in LOD is likely due to an enhanced post-delivery mother-to-infant transmission.

Molecular diagnosis of Helicobacter pylori infection in gastric biopsies: Evaluation of the Amplidiag® H. pylori + ClariR assay.

BACKGROUND: Adapted treatments for Helicobacter pylori infection, guided by determining antimicrobial resistance, are associated with high eradication rates. We evaluated the performance of the Amplidiag® H. pylori + ClariR PCR assay (Amplidiag® ) for detecting H. pylori and its clarithromycin resistance from gastric biopsies taken during endoscopy in comparison to culture and our "in-house" PCR. MATERIALS AND METHODS: A total of 127 gastric biopsies were analyzed (98 adults; 29 children). Culture, PCR Amplidiag® , and in-house PCR were performed in parallel. The in-house PCR combined amplification and sequencing of a 267-bp fragment of the H. pylori 23S rRNA gene. Discrepancies were controlled by amplification of glmM gene. RESULTS: For detection of H. pylori, Amplidiag® and the in-house PCR were concordant in 118 of 127 of cases: 66 negative and 52 positive. Discrepancies were observed in nine cases, all with low bacterial load: Amplidiag® did not detect seven biopsies positive on in-house PCR but detected two positive biopsies that were negative on in-house PCR. Among the 19 of 52 (36%) H. pylori cases resistant to clarithromycin, only four biopsies with mixed populations exhibited discordant results between the two PCR methods. The A2142T mutation was not detected by Amplidiag® . With the in-house PCR and amplified glmM gene as the reference method, the sensitivity and specificity of Amplidiag® was 88.5% (95% confidence interval 83-94.1) and 100%. CONCLUSION: This study demonstrated the high sensitivity of the PCR-based Amplidiag® H. pylori test, especially with low H. pylori load, and the probability of its clarithromycin resistance analysis. For clinical use, a well-designed trial with a large scale of samples may still be needed.

Biofilm production by Haemophilus influenzae and Streptococcus pneumoniae isolated from the nasopharynx of children with acute otitis media.

BACKGROUND: Biofilm production by Haemophilus influenzae and Streptococcus pneumoniae has been implicated in the pathogenesis of otitis media, mainly in chronic and recurrent cases. We studied the "in vitro" biofilm production by these 2 species isolated alone or together from the nasopharynx of children with acute otitis media. METHODS: The studied strains were from 3 pneumococcal conjugate vaccine (PCV) periods: pre-PCV7, post-PCV7/pre-PCV13 and post-PCV13. A modified microtiter plate assay with crystal violet stain was used to study the biofilm production of 182 H. influenzae and 191 S. pneumoniae strains. RESULTS: Overall, 117/181 (64.6%) H. influenzae and 128/191 (66.8%) S. pneumoniae strains produced biofilm. The proportion of biofilm-producing H. influenzae strains was greater with than without the isolation of S. pneumoniae in the same sample (75.5% vs 52.3%, p = 0.001). Conversely, the proportion of biofilm-producing S. pneumoniae strains was not affected by the presence or not of H. influenzae (66.3% vs 67.4%). S. pneumoniae serotypes 6B, 15B/C, 19A, 35F and 35B were the better biofilm producers (80%). Serotypes 11A, 14, 15A, 19F and 19A were more associated with H. influenzae biofilm-producing strains. Overall, 89/94 (94.6%) of cases with combined isolation showed biofilm production by S. pneumoniae or H. influenzae. CONCLUSION: This study emphasizes the high proportion of biofilm production by H. influenzae and S. pneumoniae strains isolated from the nasopharynx of children with acute otitis media, which reinforces the results of studies suggesting the importance of biofilm in the pathogenesis of acute otitis media.

Molecular characterization of Helicobacter pylori resistance to rifamycins.

INTRODUCTION: Antibiotic resistance is a major contributing factor in treatment failure of Helicobacter pylori eradication. Rifabutin (RB) is a rescue treatment and rifampicin (RP) is used to screen RB resistance in vitro. The aim of this study was to evaluate the rate of rifamycins resistance and to determine the mutations in the rpoB gene conferring resistance to discuss the current break point. METHODS: Antimicrobial susceptibility to RP was first determined by E-test for 1015 H. pylori isolates. RP and RB MICs were then determined by agar dilution method for strains with MIC of RP > 1 mg/L, and the rpoB gene was sequenced. RESULTS: Overall, 54 of 1015 strains exhibited a RP MIC > 1 mg/L by agar dilution method. Among these 54 strains, 10 had MICs of RP > 4 mg/L and RB ≥ 1 mg/L. They all carried at least one mutation in the rpoB gene at codons 530, 538, 540, 525 in the RP resistance-determining region (RRDR). Implication of the mutation L547F was confirmed by site-directed mutagenesis experiment. In contrast, among the 44 H. pylori isolates with a MIC of RP comprised between 2 and 4 mg/L, only 4 of 44 (9%) strains exhibited a mutation in rpoB, but outside RRDR (codons 470, 499, 636, or 657). For 31 of 44 tested strains, the RB MICs were ≤0.064 mg/L. CONCLUSION: These results suggest that H. pylori isolates should be classified as resistant to RP for MICs > 4 mg/L. We considered that the optimal cut off for RB was ≥0.125 mg/L. We report a new mutation responsible for rifamycins, resistance, L547F.

Helicobacter pylori infection in children.

Helicobacter pylori infection in children differs from that in adults, from the point of view of epidemiology, host response, clinical features, related diseases, and diagnosis, as well as treatment strategies. The prevalence of H. pylori infection, in both children and adults, is decreasing in the Western World as well as in some developing countries, which contrasts with the increase in childhood asthma and allergic diseases. Recurrent abdominal pain is not specific during H. pylori infection in children. The role of H. pylori infection and failure to thrive, children's growth, type I diabetes mellitus (T1DM) and celiac disease remains controversial. The main initial diagnosis is based on upper digestive endoscopy with biopsy-based methods. Nodular gastritis may be a pathognomonic endoscopic finding of childhood H. pylori infection. The infection eradication control is based on validated noninvasive tests. The main cause of treatment failure of H. pylori infection is its clarithromycin resistance. We recommend standard antibiotic susceptibility testing of H. pylori in pediatric patients prior to the initiation of eradication therapy. H. pylori treatment in children should be based on an evaluation of the rate of eradication in the local population, a systematic use of a treatment adapted to the susceptibility profile and a treatment compliance greater than 90%. The last meta-analysis in children did not show an advantage for sequential therapy when compared to a 14-day triple therapy. Finally, the high rate of antibiotic resistance responsible for therapy failure in recent years justifies the necessity of a novel vaccine to prevent H. pylori infection in children.

Myeloid HIF-1 is protective in Helicobacter pylori-mediated gastritis.

Helicobacter pylori infection triggers chronic inflammation of the gastric mucosa that may progress to gastric cancer. The hypoxia-inducible factors (HIFs) are the central mediators of cellular adaptation to low oxygen levels (hypoxia), but they have emerged recently as major transcriptional regulators of immunity and inflammation. No studies have investigated whether H. pylori affects HIF signaling in immune cells and a potential role for HIF in H. pylori-mediated gastritis. HIF-1 and HIF-2 expression was examined in human H. pylori-positive gastritis biopsies. Subsequent experiments were performed in naive and polarized bone marrow-derived macrophages from wild-type (WT) and myeloid HIF-1α-null mice (HIF-1(Δmyel)). WT and HIF-1(Δmyel) mice were inoculated with H. pylori by oral gavage and sacrificed 6 mo postinfection. HIF-1 was specifically expressed in macrophages of human H. pylori-positive gastritis biopsies. Macrophage HIF-1 strongly contributed to the induction of proinflammatory genes (IL-6, IL-1ß) and inducible NO synthase in response to H. pylori. HIF-2 expression and markers of M2 macrophage differentiation were decreased in response to H. pylori. HIF-1(Δmyel) mice inoculated with H. pylori for 6 mo presented with a similar bacterial colonization than WT mice but, surprisingly, a global increase of inflammation, leading to a worsening of the gastritis, measured by an increased epithelial cell proliferation. In conclusion, myeloid HIF-1 is protective in H. pylori-mediated gastritis, pointing to the complex counterbalancing roles of innate immune and inflammatory phenotypes in driving this pathology.

A one-step immune-chromatographic Helicobacter pylori stool antigen test for children was quick, consistent, reliable and specific.

AIM: This French study assessed a quick, noninvasive, immuno-chromatographic, Helicobacter pylori (H. pylori) stool antigen test for detecting infections in children. METHODS: We enrolled 158 children, with a median age of 8.5 years (range eight months to 17 years), with digestive symptoms suggesting upper gastrointestinal tract disease. Upper digestive endoscopy was performed with gastric biopsy specimens for histology, a rapid urease test, culture test and quantitative real-time polymerase chain reaction. The H. pylori stool antigen test was performed twice for each child and the results were compared to the reference method. RESULTS: The reference methods showed that 23 (14.6%) of the 158 children tested were H. pylori positive. The H. pylori stool antigen test showed 91.3% sensitivity, with a 95% confidence interval (95% CI) of 86.9-95.6 and 97% specificity (95% CI 94.3-99.6), 30.84 positive likelihood ratio and 0.09 negative likelihood ratio. The test accuracy was 96.2% (95% CI 93.2-99.1). The two blinded independent observers produced identical H. pylori stool antigen test results and the Kappa coefficient for the H. pylori stool antigen test was one. CONCLUSION: The H. pylori stool antigen test was found to be a consistent, reliable, quick and specific test for detecting the H. pylori infection in children.

Diagnosis of Helicobacter pylori recurrence: relapse or reinfection? Usefulness of molecular tools.

BACKGROUND AND AIMS: Infection due to Helicobacter pylori causes many gastrointestinal diseases including peptic ulcers and gastric carcinoma. Their treatment and prevention depends on the successful eradication of H. pylori. However, even after a well-conducted treatment, H. pylori persists in about 10-30% of patients. Recurrent infections can correspond to relapse or to re-infection and require appropriate medical care. In this study, we explore retrospectively three clinical cases using molecular methods, and propose new guidelines for the diagnosis of recurrence. MATERIAL AND METHODS: Ten colonies of H. pylori were selected from the primary culture of biopsy samples taken from the antrum and fundus for each patient. The genotype of each isolated colony was determined by analyzing the polymorphism of two housekeeping genes, hspA and glmM. The genome-wide composition of H. pylori strains was studied using in house macro-arrays designed. RESULTS: Relapses were demonstrated by the stability of genotypes and the slight genetic variability of strains on macro-arrays. Two patients suffered from relapses, one and three years after H. pylori treatment. For the third patient, both the polymorphism of glmM and hspA genotypes and the diversity of CDSs identified on macro-arrays suggested that several episodes of re-infection occurred, 1-8 years after eradication. CONCLUSION: For the three clinical cases, molecular methods allowed identifying the causes of recurrent infections. We suggest to study genotype to distinguish between relapse and re-infection in order to adapt the treatment and the follow-up of patients to the nature of recurrence.

Staphylococcus aureus osteo-articular infection: usefulness of the determination of daptomycin serum concentration to explain a treatment failure.

We report two cases of treatment failure in patients with osteoarticular infection associated with Staphylococcus aureus bacteremia and receiving daptomycin. Using a published population-pharmacokinetic model and daptomycin blood level in these patients, area under the curve (AUC) was calculated and compared to the pharmacological target. For the first patient, treated with 6 mg/kg every 48 hours due to acute renal failure and then every 24 hours, the AUC was 820 mg×h×L-1, with a minimal concentration of 23.5 mg/L confirming the right dose adjustment and the absence of underdosing. The methicillin-resistant Staphylococcus aureus (MRSA) strain was still susceptible to daptomycin, but it was not sufficient to observe a favorable outcome. For the second patient, treated with 10 mg/kg/d, the steady state residual concentration was 10.4 mg/L, and the calculated AUC value was 550 mg×h×L-1. AUC/MIC values evolved during treatment to be under the cut-off for bactericidal effects (> 800 hours), and the Staphylococcus aureus (SA) strain became daptomycin resistant. This study highlights the inter-individual pharmacokinetic variation leading sometimes to drug underdosing. Drug monitoring should be encouraged in order to avoid treatment failure.

Lack of evidence for an unmet need to treat Clostridium difficile infection in infants aged <2 years: expert recommendations on how to address this issue.

The role of Clostridium difficile in causing disease in infants is unclear, and the existence of C. difficile infection (CDI) in this population is controversial. As part of the drug licensing process for new CDI therapies, a pediatric investigation plan is required to define studies in infants aged <2 years. This assumes an unmet medical need, even though clinical trials in this age group may not be feasible. Three pharmaceutical companies developing CDI treatments came together to seek advice from a panel of experts. Our unanimous opinion is that the existence of CDI is questionable in infants, and if it exists, is rare. There is therefore no unmet need for CDI treatment in this population. Interventional studies are not feasible with the current level of knowledge, and studies should be limited to noninterventional studies or open-label pharmacokinetic and safety studies to better define CDI in infants.

Usefulness of Gastric Biopsy-Based Real-Time Polymerase Chain Reaction for the Diagnosis of Helicobacter pylori Infection in Children.

OBJECTIVES: The aim of the study was to assess the usefulness of gastric biopsy-based quantitative real-time polymerase chain reaction (qPCR) for the detection of Helicobacter pylori infection and the identification of clarithromycin-resistant strains in children. METHODS: A gastric biopsy-based qPCR for the detection of H pylori infection and the identification of clarithromycin-resistant strains in children was evaluated in 62 children with infection and 341 children without infection. H pylori infection was considered by the "reference method" when culture was positive for both histology and rapid urease test (RUT). Results were compared with those obtained using the qPCR. RESULTS: The reference method versus H pylori qPCR positivity showed 95% confidence interval sensitivity 100% versus 100%, specificity 93.2% (86.9-99.4) versus 100%, positive predictive value 59.7% (47.4-71.9) versus 100%, negative predictive value 100% versus 100%, and, finally, test accuracy of 59.6% (47.3-71.8) versus 100%. Sixty-two children were found to be H pylori positive, based on the qPCR results. Among those, 31 children had both positive qPCR and culture with concordant antimicrobial susceptibility testing results, whereas 31 children had negative culture and positive qPCR. The qPCR showed a bacterial load ≥10 copies per milliliter when culture, histology, and RUT were all positive (29/31 children) versus <10 copies per milliliter when culture, histology, and RUT were all negative (25/31 children). Grades 2 and 3 histological gastritis were associated with a bacterial load ≥10 copies per milliliter for 28/35 of children versus 27/27 of grade 0 to 1 <10 copies per milliliter. CONCLUSIONS: H pylori qPCR positivity is a more precise test than the routine culture, histology, RUT alone and allows detecting low bacterial loads.

Group A Streptococcus endometritis following medical abortion.

Medical abortion is not recognized as a high-risk factor for invasive pelvic infection. Here, we report two cases of group A Streptococcus (GAS; Streptococcus pyogenes) endometritis following medical abortions with a protocol of oral mifepristone and misoprostol.

Non typable-Haemophilus influenzae biofilm formation and acute otitis media.

BACKGROUND: Non-typable Haemophilus influenzae (NT-Hi) infection is frequently associated with acute otitis media (AOM) treatment failure, recurrence or chronic otitis media. Persistence of otopathogens in a biofilm-structured community was implicated in these situations. Here, we compared biofilm production by H. influenzae strains obtained by culture of middle ear fluid (MEF) from children with AOM treatment failure and by strains isolated from nasopharyngeal (NP) samples from healthy children or those with AOM (first episode or recurrence). We aimed to evaluate an association of clinical signs and in vitro biofilm formation and establish risk factors of carrying a biofilm-producing strain. METHODS: We used a modification of the microtiter plate assay with crystal violet staining to compare biofilm production by 216 H. influenzae strains: 41 in MEF from children with AOM treatment failure (group MEF), 43 in NP samples from healthy children (NP group 1), 88 in NP samples from children with a first AOM episode (NP group 2, n = 43) or recurrent (NP group 3, n = 45) and 44 in NP samples from children with AOM associated with conjunctivitis (NP group 4). RESULTS: At all, 106/216 (49%) H. influenzae strains produced biofilm as did 26/43 (60.5%) in NP samples from healthy children. Biofilm production in MEF samples and NP samples did not significantly differ (40.5% vs 60.5%, 55.8%, 56.8% and 31.1% for NP groups 1, 2, 3 and 4, respectively). On multivariate analysis, only presence of conjunctivitis was significantly associated with low biofilm production (OR = 0.3, CI [0.16-0.60], p = 0.001). The ampicillin resistance of H. influenzae produced by penicillin-binding protein modification was significantly associated with low biofilm production (p = 0.029). CONCLUSION: We found no association of biofilm production and AOM treatment failure or recurrence. Biofilm production was low from H. influenzae strains associated with conjunctivitis-otitis syndrome and from strains with modified penicillin-binding protein.

Impact of human migrations on diversity of Helicobacter pylori in Cambodia and New Caledonia.

BACKGROUND: Helicobacter pylori is a major gastric bacterial pathogen, presumed to have established itself in the human stomach approximately 100,000 years ago. Helicobacter pylori co-evolved with its host, and human migrations shaped the expansion and the diversity of strains around the world. Here, we investigated the population structure and the genomic diversity of H. pylori in New Caledonia and Cambodia, where humans of different origins are living. METHODS: Both multilocus sequence typing (MLST) and macro-array experiments were performed to assess polymorphism of housekeeping genes and to compare differences in gene contents among strains of H. pylori. RESULTS: The macro-array analysis based on variations of the flexible gene pools was consistent with the contribution of ancestral H. pylori populations to modern strains. Most of the CDS variably present encode proteins of unknown function, selfish DNA, and transposases. In New Caledonia-where humans are of several ethnic origins-strains belonged to four different genetic populations, reflecting the diversity of human populations. Melanesians and Polynesians were infected mainly by strains assigned to hspMaori, whereas Caucasians were infected by hspWAfrica, hpEurope, and hpNEAfrica strains. In contrast, strains from Khmer patients belonged to only two subpopulations: hspEAsia and hpEurope. In the two countries, both ancient and recent human migrations may have influenced the diversity of H. pylori. CONCLUSION: Our present results are consistent with the possibility of admixture of strains in multiethnic communities. This increases the global polymorphism of H. pylori without evidence of functional change or impact on fitness and virulence.

Comparative evaluation of 29 commercial Helicobacter pylori serological kits.

BACKGROUND: Serology is a noninvasive diagnostic method for the detection of Helicobacter pylori infection. Many commercial kits are now on the market. It is necessary to assess their performances to help the user to choose the most appropriate. MATERIAL AND METHODS: The performances of 29 commercial serological tests detecting antibodies to Helicobacter pylori (17 enzyme-linked immunosorbent assay and 12 near-patient tests) were evaluated using sera from 108 patients prospectively selected from gastroenterology departments of five French hospital centers. These patients were infected (45) or uninfected (47) by H. pylori, or had doubtful results (16), according to the gold standard (culture or histology plus rapid urease test or urea breath test). The tests were evaluated by determining the usual parameters of performance: sensitivity, specificity, positive predictive value, negative predictive value, and accuracy. Two analyzes were performed including or not the 16 patients with doubtful infection as uninfected or not analyzed. RESULTS: Depending on the type of analysis, four or two of the 17 enzyme-linked immunosorbent assay tests presented excellent results with the five performance parameters >90%. Calculation of the Youden index allowed to show significantly better performances for one of the 4. Performances of the 12 near-patient tests were lower with accuracies <90% for all except one test. CONCLUSION: These data should help the users to choose the kit the most appropriate to their goals.

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

BACKGROUND: Antibiotic 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. METHODS: One 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. RESULTS: Isolates 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. CONCLUSIONS: The 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.