Clarithromycin resistance and prevalence of Helicobacter pylori virulent genotypes in patients from Southern México with chronic gastritis

In developing countries, clarithromycin resistance and frequency of re-infection are factors that contribute to high prevalence of Helicobacter pylori infection. The aim of this research was determine the prevalence of clarithromycin resistance and its relation with A2142G, A2142C and A2143G mutations in the domain V of the 23S rRNA gene of H. pylori isolates in patients from Southern Mexico with chronic gastritis. Another purpose of this work was to study the prevalence of virulent genotypes and distribution of resistant strains according to the vacA/cagA/babA2 H. pylori genotypes. One hundred forty-four patients with chronic gastritis were studied. Forty-five H. pylori strains were isolated and clarithromycin susceptibility was determined by the disk-diffusion method. The 82.2% of the strains had the combination of alleles vacA s1 m1 and the cagA gene was detected in 77.8% and 40% of the strains were babA2 positive. The vacA s1 m1 genotype was detected more frequently in cagA⁺ strains, vacA s1m1/cagA⁺/babA2^- genotype was more frequent than vacA s1m1/cagA⁺/babA2⁺, 37.8% and 33.3%, respectively. Eight strains were clarithromycin resistant, in three of these, point mutations were identified, but only in one strain the A2143G mutation associated with clarithromycin resistance was found. Other point mutations (A1821G, G1826A, T1830C, A2089G, T1600C, C1601T, C1602T, T1610C, A1611C and T1633G) that have not been associated with clarithromycin resistance were identified. The highest proportion of resistant strains was vacA s1m1/cagA⁺ (62.5%). In patients from southern Mexico with chronic gastritis, the prevalence of clarithromycin resistance is within internationally accepted range (17.8%) and allows continued use of triple therapy for H. pylori eradication. However, it is necessary to monitor the evolution of clarithromycin resistance in this area. The largest proportion of resistant H. pylori strains is not harboring the A2142G, A2142C and A2143G mutations in the 23S rRNA gene (87.5%). The vacA s1m1/cagA⁺ genotype was the most prevalent and among clarithromycin-resistant strains, this was the predominant.     

Phenotypic and Genetic Characterization of Antimicrobial Profiles of Helicobacter pylori Strains in Cuba

The study evaluated the antibiotic resistance patterns of Helicobacter pylori strains against metronidazole and clarithromycin in a hospital in Havana, Cuba. Eighty-five percent, 22.5%, and 10% of 40 H. pylori strains investigated were resistant to metronidazole, ciprofloxacin, and clarithromycin respectively but all were susceptible to amoxicillin and tetracycline. RdxA truncation was found only in metronidazole-resistant strains. In such strains, reported are eight and two novel mutations in the rdxA and frxA genes respectively. Two-point mutations in the 23S rRNA genes of clarithromycin-resistant strains were detected. A high prevalence of metronidazole resistance was found in Cuban H. pylori strains. Mutations in the rdxA gene may contribute more significantly than frxA gene to the high level of resistance to metronidazole. This study supports the need to continue monitoring the antibiotic susceptibility in H. pylori in Cuba to guide the treatment of such infection.Key words: Antibiotic resistance, Gene mutations, Helicobacter pylori, Cuba     

Efficacy of a tailored PCR-guided triple therapy in the treatment of Helicobacter pylori infection

IntroductionResistance to clarithromycin and fluoroquinolones is increasing in many countries. We aimed to assess the efficacy of a tailored PCR-guided triple therapy versus an empirical triple therapy in the treatment of H. pylori infection.Patients and methodsFrench multicenter prospective open-label randomized study to assess H. pylori and resistance to clarithromycin and levofloxacin with GenoType HelicoDR® test. Patients of the control group were treated with empirical therapy of proton pump inhibitor (PPI), amoxicillin, and clarithromycin for 7 days. Patients of the experimental group with clarithromycin-susceptible strains, clarithromycin-resistant/levofloxacin-susceptible strains, and with clarithromycin-resistant/levofloxacin-resistant strains received tailored therapy of PPI, amoxicillin, and clarithromycin for 7 days, PPI, amoxicillin, and levofloxacin for 10 days, and PPI, amoxicillin, and metronidazole for 14 days, respectively. H. pylori eradication was assessed by ¹³C urea breath test at least 28 days after the end of treatment.ResultsWe included 526 patients: 260 (49.4%) were randomly assigned to empirical triple therapy and 266 (50.6%) to tailored therapy. Clarithromycin and levofloxacin resistances were 23.3% and 12.8%, respectively. Follow-up urea breath test was available for 415 (78.9%) patients. Tailored therapy was superior to empirical therapy in terms of eradication (85.5% vs. 73.1%, RR = 1.85, 95%CI [1.25–2.78], p = 0.003). Findings were consistent in the susceptibility analysis using multiple imputation (RR = 1.61, 95%CI [1.14–2.27], P = 0.003) and per-protocol analysis (RR = 1.89, 95%CI [0.25–2.78], p = 0.003).ConclusionIn a country with a high level of clarithromycin resistance, tailored PCR-guided therapy was superior to empirical triple therapy for H. pylori eradication (https://www.ClinicalTrials.gov: NCT01168063).     

Multiple and mixed Helicobacter pylori infections: Comparison of two epidemiological situations in Tunisia and France

Individuals can be infected by either a single or multiple strains of Helicobacter pylori. Multiple infection with genetically different isolates and particularly mixed infection with both antibiotic-susceptible and resistant isolates are difficult to detect and should impact the effectiveness of eradication treatment. It is largely assumed that multiple infections are more frequent in developing countries but an actual comparison developing/developed using a single methodology has never been reported. To compare the prevalence of multiple and mixed H. pylori infection in Tunisia and France, we conducted a prospective study including 42 H. pylori-culture positive infected patients (21 Tunisian and 21 French) never previously treated for H. pylori infection. One gastric biopsy was collected from antrum. Three to eleven (mean = 9) colonies were isolated from each biopsy. A total of 375 different isolates were genotyped using RAPD fingerprinting and antimicrobial susceptibility testing was performed on amoxicillin, clarithromycin, ciprofloxacin, rifampicin, tetracycline and metronidazole with E-tests. Multiple infection was defined by different RAPD fingerprintings among the different isolates from a single patient. Mixed infection was defined by different resistance profiles among the different isolates from a single patient. Multiple H. pylori infection is more prevalent in Tunisia than in France. It occurred in ten (48%) Tunisian patients and in one (5%) French patient (p < 0.001). Mixed infection is common (24%), it occurred in 4 (19%) Tunisian patients and in 6 (29%) French patients (p = 0.46) and was mainly (8/10) due to genetically related clones in single infection.     

Aktuelle Daten und Trends zur Antibiotikaresistenzentwicklung von Clostridium difficile

Clostridium difficile is the most common pathogen causing antibiotic-associated diarrhea. Antibiotic therapy also favors the development and the epidemic spreading of multiresistant strains. In this present retrospective study clinical isolates from the University of Saarland Medical Center and of other German isolate referring hospitals were characterized by genotyping and antibiotic resistance testing. The most prevalent strains were ribotypes 001 (18%), 014 (16%) and 027 (15%). Sensitivity to metronidazol and vancomycin was demonstrated for 99.7?% of the clinical isolates independent of the genotype. Of the isolates 96?% were rifampicin susceptible; however, significantly more cases of rifampicin resistance were found among 027 strains (12?%). Of the isolates 58% were clarithromycin sensitive and 57% moxifloxacin sensitive. In contrast to the various sporadic genotypes the majority of epidemic strains were macrolide or fluoroquinolone resistant (001, 027 and 078); however, discrimination between epidemic strains by antibiotic resistance profiles could not be discerned. A combination of consistent adherence to hygiene management guidelines and to a prudent and rational use of antimicrobials (antibiotic stewardship) may help to reduce the total number of C. difficile infections (CDI) and also the selection of multiresistant strains. On the other hand in the collection of isolates the sensitivity towards the standard oral antibiotic agents used for C. difficile treatment appears to be unimpaired by the global changes of C. difficile resistant profiles.     

An Integrated Model for the Management of Co-Occurring Psychiatric and Substance Disorders in Managed-Care Systems

Objective: To use the System of Objectified Judgement Analysis (SOJA) method for the rational selection of Helicobacter pylori eradication therapies for formulary inclusion. Design: Drug selection for the eradication therapy of H. pylori is made by means of the SOJA method. In this formulary decision-making model, selection criteria for a given class of drugs are prospectively defined and weighted by a panel of experts. The following criteria (relative weight) were used: variability of pharmacokinetics; drug interactions; resistance to antibacterials; efficacy; general adverse effects; complexity of the regimen; acquisition cost and clinical documentation. Only published studies with at least 30 evaluable patients were considered, at least 3 studies had to be available per treatment regimen and efficacy had to be assessed on an intent-to-treat basis. Main outcome measures and results: The regimens containing clarithromycin and an imidazole antibacterial in combination with omeprazole or ranitidine bismutrex showed the highest scores for eradication of H. pylori. The combinations amoxicillin/clarithromycin and omeprazole or lansoprazole showed slightly lower eradication rates and were more costly. The eradication rates obtained with 2-drug regimens were low, resulting in a low overall SOJA score. No quadruple regimens could be included, as none of the regimens fulfilled the inclusion criteria. This was also true for the classical triple therapy with bismuth/metronidazole/tetracycline. Conclusion: The present score is specific for the Netherlands, as Dutch acquisition costs and data on resistance were used. In other countries, with different degrees of imidazole and clarithromycin resistance, other regimens may be more appropriate. The SOJA score will be regularly updated through the internet to include relevant new studies or new successful eradication regimens. The interactive program offers groups of physicians the opportunity to discuss the optimal H. pylori eradication regimen, based on their weighting of the criteria.     

Determination of Helicobacter pylori CagA EPIYA types in Iranian isolates with different gastroduodenal disorders

Helicobacter pylori (H. pylori) cytotoxin-associated gene A protein (CagA) is the first bacterial oncoprotein identified in human gastric cancer. The carboxy terminus (C-terminus) of CagA may undergo polymorphisms to give different types of EPIYA motifs, which may exist in single or combination form within the infected host. Sequence variations in the 3′ region of the cagA impose a functional impact to the translated CagA protein. In this study, we characterize the diversity of the H. pylori CagA EPIYA types, their associations with their hosts’ clinical status, and the potential of using the whole 3′ region of cagA as a genetic marker for the identification of Iranian isolates from different geographic locations. H. pylori was detected in 71 out of 177 examined Iranian patients with different gastroduodenal disorders. Genotyping of the cagA variable EPIYA motif was screened by polymerase chain reaction and gene sequencing was performed for all the detected cagA positive isolates. Out of 44 cagA-positive isolates, there were EPIYA motifs of ABC (30 isolates), ABCC (4 isolates), ABCCC (1 isolate), mixed types (6 isolates) and new types (3 isolates). We termed the newly identified EPIYA segment as EPIYA- A-B/C. Sequence analysis also showed the presence of uncommon EPIYA-like motifs (EPIYT and QPIYP) in some isolates. It is postulated that EPIYA type conversion through the presence of different repetitive sequences give rise to these new strains. We also identified 3 sequence motifs which may be applied as genetic markers for Iranian strains. Furthermore, EPIYA types ABCC and EPIYA- A-B/C showed association with duodenitis and gastric cancer, respectively. Further study with a larger number of strains is necessary to confirm the proposed associations and the identified sequence motifs as genetic markers. In conclusion, our study demonstrates the dominancy of Western type cagA gene and the diversity of the CagA C-terminal region in the tested Iranian strains.     

The Association between Serum Vitamin D Levels and Helicobacter pylori Presence and Eradication

Background: The success of Helicobacter pylori (H. pylori) eradication depends on several host and treatment factors. Serum vitamin D levels may be associated with H. pylori infection and eradication rates. We investigated the association between vitamin D and H. pylori infection and eradication, using a large electronic database based on medical records from a population-based health maintenance organization. Methods: Data regarding adults who underwent H. pylori testing and had vitamin D measurements within one month of H. pylori testing were collected. H. pylori infection was ascertained using urea breath or stool antigen tests. A negative H. pylori test following a positive result implied eradication. Multivariate regression models were constructed to assess associations between H. pylori infection, eradication, and vitamin D. Results: Among 150,483 members who underwent H. pylori testing from 2009 to 2018, 27,077 (18%) had vitamin D measurements. Vitamin D levels were inversely associated with H. pylori infection, p < 0.001. The odds of a positive H. pylori test were 31% higher among patients with vitamin D levels <20 ng/mL, compared with those with levels ≥20 ng/mL (OR 1.31, 99% CI 1.22–1.4, p < 0.001). Purchase of vitamin D supplements was associated with a negative subsequent H. pylori test (p < 0.001). Mean vitamin D levels were moderately higher in those with successful vs. failed H. pylori eradication (19.34 ± 9.55 vs. 18.64 ± 9.61, p < 0.001). Conclusions: Vitamin D levels are associated with H. pylori infection. Increased vitamin D levels are associated with successful H. pylori eradication. Vitamin D may have a role in H. pylori eradication.     

中国幽门螺杆菌基因组多样性与种群结构分析

目的 了解中国幽门螺杆菌（Helicobacter pylori,HP）基因组特征及种群结构。方法 利用中国不同地域不同疾病分离的10株HP的基因组序列,并整合公共数据库中其他地域的HP基因组数据,通过比较基因组和生物信息学方法分析中国HP的基因组与种群结构特征。结果 中国HP核心基因为1 203个。菌株特异基因为19～32个,这些基因可能与中国HP在不同地域、不同疾病宿主中的适应性进化有关。基因组变异较大区域主要集中在编码限制修饰系统的基因和编码四型分泌系统的基因。基于核心基因组单核苷酸多态性（SNP）的种群分析确定中国菌株均属于hpEastAsia群,hspEAsia亚群,且不同地域菌株具有地域聚集性特点。在3株中国HP基因组序列中发现了前噬菌体序列,携带噬菌体组装所需的必要元件。结论 基于核心基因组SNP分析中国菌株均属于hpEastAsia群,hspEAsia亚群,且具有地域聚集性。为深入挖掘中国不同地域不同疾病相关HP的遗传特征及研究噬菌体在HP进化与致病中的作用奠定了基础。     

The changing phenotypes and genotypes of invasive pneumococcal isolates from children in Shenzhen during 2013–2017

BackgroundThe phenotypes and genotypes of Streptococcus pneumoniae isolated from invasive pneumococcal diseases (IPDs) were changing all the time. To monitor these changes of phenotypes and genotypes of S. pneumoniae isolates from children, we examined antibiotic susceptibility, serotype distribution and sequence types (STs) of S. pneumoniae, which were isolated before the 13-valent pneumococcal conjugate vaccine (PCV13) introduced into China.MethodsStrains were isolated from children less than 14 years old between January 2013 and May 2017 from Shenzhen Children’s Hospital. Serotypes, antibiotic resistance, and genotypes of these isolates were determined using capsular swelling, E-test, and multi-locus sequence typing, respectively.ResultsA total of 94 S. pneumoniae strains were isolated, which belonged to 15 serotypes. The five most prevalent serotypes were 19F (25.5%), 19A (19%), 14 (17%), 23F (7.5%), and 6B (9.6%). We found 42 STs for these isolates. The most abundant STs were ST271 (24.4%), ST876 (17%), and ST320 (10.6%), mainly related to 19F, 14, and 19A, respectively. The potential coverage of PCV13 was 87.2%. Among non-meningitis isolates, the resistance rates to penicillin and ceftriaxone were 0% and 2%. However, the meningitis isolates showed high resistance to penicillin (80%) and ceftriaxone (20%). Most of these isolates (95.7%) were resistant to erythromycin, and 66 (70.2%) strains carried the ermB gene and 24 (25.5%) strains carried both the ermB and mefA/E genes. Serotype 19A showed the highest mean minimum inhibitory concentration (MIC) for penicillin (MIC = 1.486) than the other serotypes, but no significant difference in penicillin MIC among the three main STs (ST271, ST320, and ST876).ConclusionsThe phenotypes and genotypes of invasive pneumococcal isolates from Shenzhen Children’s Hospital have changed with the passage of time. Compared with PCV7, PCV13 can more effectively protect Chinese children from IPDs. To some extent, these changes are possibly related to the usage of antibiotics and vaccines.     

Co-harboring of mcr-1 and β-lactamase genes in Pseudomonas aeruginosa by high-resolution melting curve analysis (HRMA): Molecular typing of superbug strains in bloodstream infections (BSI)

BackgroundColistin resistance in P. aeruginosa (CRPA) is due to the appearance of superbug strains. As this pathogen gains more transferrable resistance mechanisms and continues to adapt to acquire additional resistance mechanisms during antimicrobial therapy rapidly, we face the growing threat of CRPA in bloodstream infections (BSI). This study designed to evaluate the frequency of CRPA strains producing different β-lactamases by the High-Resolution Melting Curve Analysis (HRMA) method in BSI and to characterize the different types by multilocus sequence typing (MLST).Material and methodsSixty-nine (69) P. aeruginosa isolates were collected from blood culture. MIC E-test methods examined the antimicrobial susceptibilities of the bacterial isolates. Detection of resistant strains performed by using HRMA assay.ResultsThe strains resistant to amikacin (n = 11; 15.94%) and colistin (n = 10; 14.49%) were the least abundant and the gentamicin (n = 56; 82.6%) and ciprofloxacin (n = 67; 97.10%) resistant strains were the most frequent. Also, 39 isolates (56.52%) considered as multidrug-resistant (MDR), 20 isolates (28.98%) as extensively drug resistant (XDR), and 11 isolates (15.94%) as Pandrug Resistance (PDR). Further, 32 isolates (46.37%) considered as AmpC producer, and 28 isolates (40.57%) were considered an MBL producer. According to HRMA results, the blaSPM gene was detected in 19 isolates (27.53%), blaNDM gene in 11 isolates (15.94%), blaFOX gene in 31 isolates (44.92%), mcr-1 gene in 10 isolates (14.49%), blaACC and blaVIM genes in 27 isolates (39.13%), and blaTEM gene was reported in 20 isolates (28.98%). Furthermore, P. aeruginosa PASGNDM699, ST3340, and ST235 identified in 1.44%, 11.59% and 17.39% isolates, respectively.ConclusionCRPA strains play an essential role in the spread of antibiotic resistance in BSI. Likewise, the HRMA method was sensitive and specific for the detection of superbugs. Moreover, MLST analysis of a diverse collection of P. aeruginosa from blood culture suggests that particular strains or clonal complexes are associated with antibiotic resistance profile.     

Prevalence and Spread of Multidrug Resistant Escherichia coli Isolates Among Nursing Home Residents in the Southern Part of the Netherlands

ObjectivesEmpiric antibiotic treatment should be based on recent surveillance data. Therefore, we conducted a surveillance of (multidrug) resistance of Escherichia coli and antibiotic use among Dutch nursing home (NH) residents. Pulsed-field gel electrophoresis and multilocus sequence typing were used to describe the spread of multidrug-resistant strains.DesignObservational study.SettingFive NHs in the southern part of the Netherlands.ParticipantsA total of 337 NH residents from both somatic and psychogeriatric wards.MeasurementsThe prevalence and spread of antibiotic resistance and multidrug resistant E. coli isolates collected from urine samples and antibiotic use among the NH residents were investigated.ResultsA total of 208 E. coli isolates were collected from 308 urine samples. Resistance to amoxicillin-clavulanic acid was 23% and resistance to ciprofloxacin was 16%. Resistance to trimethoprim-sulfamethoxazole was 19%, whereas nitrofurantoin resistance was less than 1%. Multidrug resistance was observed in 28 of the 208 isolates (13%). Several isolates showed a similar pulsed-field gel electrophoresis pulsotype and multilocus sequence typing type. Sequence type (ST) 131 was the most prevalent (48%) and was demonstrated in all NHs and with four different pulsotypes. Consumption of antibiotics for systemic use was 64.4 defined daily dose (DDD)/1000 residents/day. Amoxicillin-clavulanic acid was most frequently prescribed (20.92 DDD/1000 residents/day), followed by the quinolones (14.8 DDD/1000 residents/day).ConclusionWe observed a high prevalence of antibiotic resistance and antibiotic use. In particular, the use of and resistance to fluoroquinolones is concerning. Because of the high prevalence of resistance, many agents are no longer suitable for empiric treatment. E. coli ST131, which has also been demonstrated in this study, poses a potential risk to this vulnerable population. We have clearly demonstrated that the resistance among NH residents is different from elderly living at home and hospitalized patients, and with the emergence of resistant strains, such as ST131, NHs are a potential reservoir for multidrug resistant bacteria.     

Synergistic effect of anti-Helicobacter pylori urease immunoglobulin Y from egg yolk of immunized hens and Lactobacillus johnsonii No.1088 to inhibit the growth of Helicobacter pylori in vitro and in vivo

Helicobacter pylori is a pathogenic bacterium that infects the stomach, causing chronic gastritis; and it is also considered to be related to the occurrence of gastric cancers. Although some eradication regimens including multiple antibiotics have been developed, the emergence of resistance to antibiotics becomes problematic. Therefore, other approaches to compensate or augment the effects of standard regimens are needed. In this study, we examined the possible synergistic effects of anti-H. pylori urease IgY and Lactobacillus johnsonii No.1088 (LJ88) both in vitro and in vivo. Anti-H. pylori urease IgY was purified from egg yolks laid by the hens immunized with urease purified from H. pylori. LJ88 is a unique strain of lactic acid bacterium isolated from human gastric juice, and it has been reported to inhibit H. pylori both in vitro and in vivo. The in vitro mixed culture study showed that anti-H. pylori urease IgY augmented the anti-H. pylori activity of LJ88 against both clarithromycin-sensitive and -resistant H. pylori strains. In a germ-free mice infection model, combined administration of daily anti-H. pylori urease IgY and weekly living LJ88 significantly reduced H. pylori infections, whereas either monotherapy did not. In an in vivo human gut microbiota-associated mice model, not only daily administration of living LJ88 but also heat-killed one significantly reduced an H. pylori infection in the stomach when combined with anti-H. pylori urease IgY. The extent of reduction of the stomach H. pylori by such a combination therapy was larger than that reported for LJ88 monotherapy. These results taken together revealed a synergistic effect of anti-H. pylori urease IgY and living or heat-killed LJ88, thus suggesting that such a combination might be a promising therapy to possibly compensate and/or augment standard anti-H. pylori regimens.     

Serotype distribution and antibiotic resistance of 140 pneumococcal isolates from pediatric patients with upper respiratory infections in Beijing, 2010

In the present study, the serotype distribution and antibiotic resistance of S. pneumoniae from pediatric patients with upper respiratory infections in Beijing, 2010 were described. 140 pneumococcal isolates were obtained, and the prevailing five serotypes were 19F (18.6%), 23F (9.3%), 14 (9.3%), 15 (9.3%), and 6A (7.1%). The vaccine coverage of PCV7, PCV10, and PCV13 were 43.6%, 43.6%, and 60.0%, respectively. According to the CLSI 2010 criteria, 99.3% of the S. pneumoniae isolates were susceptible to penicillin. The resistance rates to erythromycin and azithromycin were 96.4% and 97.1%, respectively. Meanwhile, 64.3% (90/140) of all pneumococcal isolates were multidrug-resistant S. pneumoniae (MDRSP). PCV13 covered 68.9% (62/90) of MDRSP strains, whereas it was 47.8% (43/90) for PCV7. ErmB was the dominant macrolide-resistance gene, whereas 30.4% pneumococcal isolates expressed both ermB and mefA. No isolate expressed ermTR. The potential coverage of PCV13 is higher than PCV7 and PCV10 because high rates of serotypes 6A and 19A, and the conjugate vaccines could prevent the spread of MDRSP. S. pneumoniae is still sensitive to penicillin. The resistance rate of S. pneumoniae to macrolides is high and ermB is the dominant macrolide-resistance gene in China, so continued surveillance of the antimicrobial susceptibility of S. pneumoniae may be necessary.     

Épidémiologie de la flore nasopharyngée au cours des otites moyennes aiguës de l'enfant de décembre 2000 à mars 2001

Method. – A French multicentric survey was made between December 2000 and March 2001 on 734 children (6 months–6 years) presenting with acute otitis media (AOM).Results. – A total of 1133 bacterial strains were isolated from nasopharyngeal secretions, the 3 main pathogens were S. pneumoniae (409 isolates, 36%), H. influenzae (328 isolates, 29%) and M. catarrhalis (275 isolates, 24%). The overall NP carriage rate for S. pneumoniae reached 56%. Among the 409 pneumococcal strains, 63% showed reduced susceptibility to penicillin (PRSP). Thirty two percent of PRSP isolates belonged to serotype 19, the other predominant resistant serotypes were 23, 6, 14 and 9. The analysis of PRSP strain distribution showed that resistance concerned all of France and was homogeneous, with an incidence superior to 50% in all regions, except for Alsace. H. influenzae was isolated from nasopharyngeal flora in 45% of children. 43% of H. influenzae isolates produced a β-lactamase with large variations in regional distribution (13–64 % of isolates). The overall NP carriage rate for H. influenzae was 19%. Less than 1% of H. influenzae isolates were ampicillin-resistant without producing β-lactamase. Nasopharyngeal carriage rate for M. catarrhalis was 37%, with 97% of isolates producing β-lactamase.Conclusion. – Evidence of geographical variation in the incidence of PRSP and β-lactamase-producing H. influenzae stresses the need of therapeutic policies adapted to regional epidemiology. The introduction of the heptavalent pneumococcal conjugate vaccine and the diversification of first-line antibiotherapy can only have beneficial effects in terms of cost and bacterial epidemiology.     

Design and immunological properties of Helicobacter pylori glycoconjugates based on a truncated lipopolysaccharide lacking Lewis antigen and comprising an α-1,6-glucan chain

To investigate the vaccine potential of H. pylori lipopolysaccharide (LPS), truncated LPS of H. pylori strain 26695 HP0826::Kan lacking O-chain polysaccharide and comprising an extended α-1,6-linked glucan chain was conjugated to tetanus toxoid (TT) or bovine serum albumin (BSA). Two approaches were used for delipidation or partial delipidation of H. pylori LPS: (1) mild hydrolysis resulting in delipidated LPS (dLPS) and (2) treatment with anhydrous hydrazine resulting in removal of O-linked fatty acids (LPS-OH). Both LPS-OH and dLPS were covalently linked through a 2-keto-3-deoxy-octulosonic acid (Kdo) residue to a diamino group-containing spacer, followed by conjugation to thiolated TT or BSA to give conjugates LPS-OH-TT, dLPS-BSA and dLPS-TT, respectively. The LPS-OH-TT, dLPS-BSA and dLPS-TT conjugates were immunogenic in both rabbits and mice, inducing strong and specific IgG responses against homologous and heterologous strains of H. pylori. Moreover, the rabbit post-immune sera showed cross-reactivity against clinical isolates of H. pylori in a whole-cell indirect ELISA, which was further confirmed by indirect immunofluorescent microscopy. A tenfold stronger IgG immune response to the immunizing antigen was generated in mice and rabbits that received dLPS-containing conjugate. The post-immune sera of rabbits immunized with LPS-OH-TT, dLPS-BSA or dLPS-TT displayed significant bactericidal activity against mutant and wild-type α-1,6-glucan-expressing strains and selected clinical isolates of H. pylori. Finally, partial protection against H. pylori challenge was demonstrated in mice vaccinated with dLPS-TT conjugate adjuvanted with cholera toxin. In summary, this study shows that glycoconjugates based on delipidated or partially delipidated LPS from H. pylori 26695 HP0826::Kan mutant induce broadly cross-reactive functional antibodies in immunized animals and should be considered for further vaccine development and testing.     

Helicobacter pylori outer membrane protein Q allele distribution is associated with distinct pathologies in Pakistan

Helicobacter pylori (H. pylori) strains expressing outer membrane protein Q (HopQ) promote adherence to the gastric epithelial cell. We characterized HopQ alleles in relation to H. pylori-related disease, histology and virulence markers. Gastric biopsies were obtained at esophagogastroduodenoscopy from patients with upper gastrointestinal symptoms. H. pylori culture, histology and polymerase chain reaction (PCR) for HopQ types, cagA, cagA-promoter and vacA alleles were performed. DNA extracted was used for PCR. Sequencing of PCR products of HopQ types 1 and 2 was followed by BLAST query. We examined 241 H. pylori isolates. HopQ type 1 was positive in 70 (29%) isolates, type 2 in 60 (25%) isolates, while both type 1 and type 2 in 111 (46%) H. pylori isolates, respectively. Nonulcer dyspepsia (NUD) was associated with HopQ type 2 in 48 (41%) isolates, while gastric carcinoma (GC) in 37 (53%) (P < 0.001) with type 1 isolates. Gastric ulcers (GU) were 39 (46%) (P < 0.001) in H. pylori infection with multiple HopQ alleles compared to 6 (23%) in HopQ type 1. Multivariate analysis demonstrated that multiple HopQ alleles were associated with GU OR 2.9 (1.07–7.8) (P = 0.03). HopQ type 1 was associated with cagA 58 (84%) (P < 0.001) and cagA-promoter 58 (83%) (P < 0.001) compared to 14 (23%) and 17 (28%) respectively, in type 2. VacAs1a was associated with HopQ type 1 in 59 (84%) isolates compared to HopQ type 2 in 35 (58%) (P = 0.002) isolates. VacAm1 was associated with HopQ type 1 in 53 (76%) isolates compared to HopQ type 2 in 32 (53%) (P = 0.004) isolates. H. pylori infection with multiple HopQ alleles was predominant. H. pylori infection with single HopQ type 1 was associated with GC in the presence of other H. pylori virulence markers.     

Prevalence of Antimicrobial Resistance in Escherichia coli Strains Isolated from Fishery Workers

ObjectivesThis study aimed to characterize the prevalence of antibiotic resistance in Escherichia coli isolates from the fecal samples of fishery workers who work in fish farms and often use antibiotics for the feeding fishes.MethodsSeventy-three E. coli strains isolated from the fecal samples of fishery workers and 180 isolates from a control group of restaurant workers were tested for antibiotic resistance by agar disk diffusion with 16 antimicrobial agents.ResultsAbout 30% of isolates from each group showed antimicrobial resistance to ampicillin, and 60% of isolates from fishery workers and 41% from restaurant workers were resistant to tetracycline. The isolates showed higher resistance to cephalothin and cefoxitin than to other cephem antibiotics and to gentamicin than to other aminogycosides. Our data indicated that fecal E. coli isolates from fishery workers showed higher antibiotic resistance than those of non-fishery workers (restaurant workers), especially to cephalothin, tetracycline, and trimethoprim–sulfamethoxazole (p < 0.05). However, rates of multidrug resistance were similar among the fishery workers and restaurant workers.ConclusionFrequent use of antibiotics may cause increased antibiotic resistance in the human microbiome.     

Individual hosts carry H. pylori isolates with different cagA features – motifs and copy number

BackgroundH. pylori strains with different genetic contents may infect different or an individual human host. Genetic diversity of cagA is thought to contribute to differences in H. pylori strains pathogenicity. In this study, diversity of cagA genotype, EPIYA motif and copy number was assessed in H. pylori single colonies isolated from individual patients.Materials and methodsGastric biopsies from 14H. pylori-positive dyspeptic patients were cultured on selective brucella blood agar and incubated at 37 °C under microaerobic conditions. Four single colonies were obtained from each biopsy subculture on brucella blood agar under similar incubation condition. Presence of cagA and types of EPIYA motifs was determined by polymerase chain reaction (PCR) and cagA copy number by quantitative real-time (RT) PCR.ResultsSingle colonies of 5 patients showed no variation in cagA genotype, EPIYA motif and copy number. Out of the remaining 9 patients, 1 patient showed presence or absence of cagA gene, 2 patients had mixed EPIYA motifs, 2 patients had different cagA copy number, 1 patient showed absence or presence of cagA and mixed motifs, 2 patients had cagA genes with different nucleotide sequences, 1 patient showed presence or absence of cagA and difference in cagA nucleotide sequence. Four isolates that contained multiple copies of cagA, carried EPIYA-ABC motif.ConclusionGenetic diversity of cagA among single colonies isolated from individual patients represents evidence that gastric mucosa of every individual is colonized with a specific and heterogeneous population of H. pylori. Future studies on patients in different disease groups may elucidate the role of mixed populations of H. pylori in development of gastric diseases.