Development of a plating medium for selection of Helicobacter pylori from water samples

The goal of this study was to develop a simple plating medium to allow large-scale screening of water samples for the presence of Helicobacter pylori. Five conventional plating media (brain heart infusion, brucella agar, Columbia blood agar base, campylobacter agar kit Skirrow, and HPSPA medium), each containing a commercial antibiotic supplement, were initially evaluated. Eight strains selected as common waterborne organisms (Acinetobacter, Aeromonas, Bacillus, Escherichia coli, Enterobacter, Enterococcus, Helicobacter pylori, and Pseudomonas strains) were individually plated onto each of these media. Three organisms (Acinetobacter, E. coli, and H. pylori) were able to grow on all five media. This growth was unacceptable since Helicobacter grows very slowly and competing organisms must be inhibited for up to 7 days. Therefore, a more selective medium (HP agar) containing a novel mixture of growth supplements plus amphotericin B and polymyxin B was developed. This medium also included a phenol red color indicator for urease production. Aliquots of nonsterile well water that contained native flora (Flavobacterium, Serratia, Citrobacter, Pasteurella, Ochrobactrum, Rahnella, and unidentified molds) and were further adulterated with the eight strains listed above (10(6) CFU of each strain per 100 ml) were spiked with H. pylori and were plated. In spite of the heavy mixed microbial load, only H. pylori colonies grew during 7 days of incubation at 37 degrees C. The color indicator system allowed presumptive identification of H. pylori colonies sooner (12 to 20 h) than the conventional media tested allowed. The HP formulation developed in this study provides a medium with superior selectivity for H. pylori from mixed microbial populations in water and reduces the time required to complete the assay.     

An evaluation of a nutrient medium for isolating and cultivating Helicobacter pylori

Selective Helicobacter agar containing the selective supplement and blood, adding ex tempore, for the isolation and cultivation of H. pylori was developed. The Helicobacter agar was studied with the use of 5 newly isolated H. pylori strains, 13 bacterial associated cultures, as well as 21 inoculated biopsy specimens of the gastric and duodenal mucosa of patients with peptic ulcer. The study revealed that Helicobacter agar ensured the growth of H. pylori and their isolation from clinical material. The positive results after the inoculation of the specimens of biopsy material on Helicobacter agar and control media was 85%. In addition, the study of Helicobacter agar showed that it also exhibited pronounced selective properties with respect to bacterial associations, not inhibiting the growth of Helicobacter organisms and retaining their main biological properties. It is possible to recommend Helicobacter agar for use in laboratory practice in diagnosing Helicobacter-associated diseases.     

Evaluation of a selective enrichment technique for the isolation of Campylobacter pylori

To cultivate Campylobacter pylori from contaminated biopsy specimens, Brucella broth was supplemented with 10% fetal calf serum, 1% Vitox, 1000 units/ml polymyxin B sulfate, 10 micrograms/ml vancomycin, and 2 micrograms/ml amphotericin B. Pseudomonas aeruginosa, Candida albicans, and Enterococcus fecalis were cocultivated with C. pylori. All four strains of C. pylori were recoverable at 24 h. When 21 C. pylori strains were studied in pure culture, 86% grew in the selective enrichment medium. In a clinical study, the selective enrichment technique resulted in isolation of C. pylori from 50% of patient samples, compared with isolation from only 36% of samples with agar cultivation. The selective enrichment technique may be more sensitive than techniques currently employed to isolate C. pylori from gastric tissue.     

Is Antrum or Corpus the Best Site for Culture of Helicobacter pylori?

Background Isolating Helicobacter pylori on culture media and performing antibiotic susceptibility testing is potentially the most useful tool for guiding antibiotic therapy, especially when antimicrobial resistance is suspected. The aim of this study was to determine whether the yield of H. pylori culture was related to the site from which the gastric specimen was obtained either before or after therapy.
Methods. Gastric mucosal biopsies from the antrum and the corpus of the stomach were cultured. H. pylori status was determined by histological assessment using the Genta stain.
Results. Fifty-two patients with documented H. pylori infection were studied: Twenty-three were tested before antibiotic therapy and 29 after therapy had failed. In 47 patients (90%), both antral and corpus culture specimens were positive. In 5 patients (10%), only one site was positive, with three false-negative antral and two false negative corpus cultures. The overall sensitivity of culture in detecting H. pylori infection was 95% (95% confidence interval = 89–98%) and was not significantly different for the antrum or corpus, either before or after therapy.
Conclusion. Culture of gastric biopsies from either the antrum or the corpus has an excellent diagnostic yield even in patients who failed antimicrobial therapy.     

Mitomycin-supplemented washed blood agar for the isolation of Shiga toxin-producing Escherichia coli other than O157:H7

AIMS: Isolation and recognition of the prominent Shiga toxin (Stx)-producing strains of Escherichia coli (STEC) serovar O157:H7 can be confirmed easily by their late fermentation of sorbitol and lack of beta-glucuronidase activity, but there has been no culture method of choice for detecting non-O157 STEC strains because of their biochemical diversity. Apart from Stx, many STEC strains produce enterohaemolysin (Ehly) regardless of their serovars. METHODS AND RESULTS: Although washed blood agar media, with or without the addition of antibiotics (vancomycin, cefixime, and cefsulodin) (WBA and WBVCCA), have been used to detect Ehly, a proportion of STEC strains consistently failed to produce haemolysin on these media. Washed blood agar medium was therefore studied further in order to increase the yield of strains producing Ehly. CONCLUSION: It was found that the addition of 0.5 microg ml(-1) of mitomycin C to the agar medium (WBMA) markedly increased the number of such strains. Thus, of 185 STEC strains comprising 95 O157 and 90 non-O157 STEC consisting of 34 serovars. Ninety-seven per cent of these strains produced haemolysis on WBMA, compared with only 76% and 83%, respectively, on WBA and WBVCCA. SIGNIFICANCE AND IMPACT OF THE STUDY: The appearance of the Ehly zone of haemolysis that was easily distinguishable from that of alpha-haemolysin was enhanced by the incorporation of mitimycin C into washed-blood medium.     

Serum- and animal tissue-free medium for transport and growth of Helicobacter pylori

The important human gastric pathogen Helicobacter pylori is the subject of many studies, and as a consequence it is frequently being transported between national and international laboratories. Unfortunately, common bacterial growth and transport media contain serum- and animal tissue-derived materials, which carry the risk of spreading infectious diseases. We have therefore developed a growth and transport medium for H. pylori, designated 'Serum- and Animal Tissue-Free Medium' (SATFM), which does not contain serum- or animal tissue-derived components. SATFM supported growth of H. pylori isolates to similar levels as obtained with serum-supplemented Brucella medium, and SATFM with 0.5% agar supported transport and storage of H. pylori strains, as 4/4 reference strains and 11/11 clinical isolates survived for at least 3 days at room temperature in SATFM, with some strains (2/15) even surviving for up to 7 days. In conclusion, SATFM can be used both as transport and growth medium for H. pylori. The formulation of SATFM may allow its use in international transport of H. pylori, and may also allow certified use in immunization studies requiring growth of H. pylori and other bacterial pathogens.     

Identification of Campylobacter pylori in gastric biopsy smears

The use of gastric biopsy imprint smears to diagnose Campylobacter pylori was compared with the use of tissue sections and cultures. Multiple gastric biopsies were taken from the mucosa of 42 patients during endoscopy. Imprint smears were prepared from the samples used to make tissue sections; other samples were used for microbiologic culture. There was a good concordance (93%) between the morphologic diagnosis of C pylori in the air-dried, Giemsa-stained smears and the tissue sections; the cytologic preparations were clearly positive in six cases (14%) whose sections contained low numbers of the organisms. There was a concordance of 83% between the combined morphologic techniques and the bacteriologic culture. Six positive cases were detected only by the morphologic techniques while one positive case was detected only by bacteriologic culture. C pylori was identified in one or more preparations of the antral biopsy specimens in 23 (55%) of the 42 cases, including 23 (74%) of the 31 cases with a final diagnosis of gastritis or ulcer. These results show the usefulness of the cytologic study of gastric biopsy smears in diagnosing C pylori infections.     

Clarithromycin Resistance of Helicobacter pylori Strains Isolated from Children’ Gastric Antrum and Fundus as Assessed by Fluorescent In‐situ Hybridization and Culture on Four‐Sector Agar Plates

Aim: To assess validity of culture on four‐sector agar plates and fluorescent in‐situ hybridization (FISH) test, and clarithromycin resistance rate in Helicobacter pylori strains isolated from children in the last 10 years. Methods: In the last 5 years, gastric biopsy specimens from antrum and fundus were taken from 89 consecutive children (median age 9 years) with H. pylori gastritis and from 21 controls. Culture was performed on 176 gastric biopsies (89 from antrum, 87 from fundus) on four‐sector agar plates, and FISH test with DNA ProbeMix^®. After its validity was evaluated, FISH test was applied on additional 119 biopsies from 68 children (68 from the antrum, 51 from the fundus) stored in the Pathology archive in the previous 5 years. Results: Culture was positive in 157 of 176 biopsies (sensitivity: 89.2%, 95% confidence interval (CI) 85–94). In 33 of 89 children (37%) resistant strains were found in one or both gastric sites. FISH test was positive in 148 of 176 biopsies from infected children (sensitivity 84.1%, 95%CI 79–89) and in none of 42 biopsies from controls (specificity 100%). When applied on archive biopsies, FISH test was positive in 96 of 119 (80.7%, 95%CI 74–88). Total children harboring resistant strains in the last 10 years, as assessed by FISH test, were 66 of 157 (42%). Mixed infection with both sensitive and resistant strains were found in 40 children (25%) and in 12 of them resistant strains were in the fundus only. Conclusions: Culture on four‐sector agar plates and FISH test had a high sensitivity and specificity and showed co‐presence of sensitive and resistant strains. In one‐third of children with mixed infection, the resistant strains were in the fundus only. Clarithromycin resistance should be assessed in biopsies both from the antrum and the fundus, utilizing antral biopsies only can underestimate its prevalence.     

Culture of Helicobacter pylori: Effect of Preimmersion of Biopsy Forceps in Formalin

Background. Treatment of antibiotic-resistant Helicobacter pylori should be based on bacterial sensitivity testing that requires the ability to isolate the bacterium from gastric mucosal biopsies. The aim of this study was to determine whether the yield for detecting H. pylori infection by culture is reduced by immersion of biopsy forceps in formalin prior to obtaining the specimen.
Materials and Methods. Gastric antral mucosal biopsies (100 specimens) from 50 patients were obtained for culture of H. pylori. An antral biopsy was taken for culture, and with the same forceps a biopsy was taken for histological examination. The biopsy specimen was removed by shaking, whereas the forceps was immersed in 10% buffered formalin for the histological investigation. The forceps was then used without rinsing to obtain a second specimen for culture from an area adjacent to the first site. H. pylori status was determined by histological assessment with the Genta stain and a rapid urease test.
Results. Fifty patients with H. pylori infection documented by histological inquiry and positive rapid urease testing entered the study; 29 had duodenal ulcers, 5 had gastric ulcers, 1 had mucosal associated lymphoid tissue (MALT) lymphoma, and 15 were without ulcer disease. The results of culture both before and after immersion in formalin were identical. One patient had both cultures negative; the sensitivity of culture for detection of H. pylori infection was 98% (95% confidence interval =93%-100%).
Conclusion. Preimmersion of biopsy forceps in formalin does not adversely affect the ability to culture H. pylori.     

Evaluation of negative results of BacT/Alert 3D automated blood culture system

Although automated continuous-monitoring blood culture systems are both rapid and sensitive, false-positive and false-negative results still occur. The objective of this study, then, was to evaluate negative results occurring with BacT/Alert 3D blood culture systems. A total of 1032 samples were cultured with the BacT/Alert 3D automated blood culture system, using both aerobic (FA) and anaerobic (FN) [corrected] media, and 128 of these samples yielded positive results. A total of 904 negative blood samples were then subcultured in 5% sheep blood agar, eosin methylene blue, chocolate agar, and sabouraud-dextrose agar. Organisms growing on these subcultures were subsequently identified using both Vitek32 (bioMerieux, Durham, NC) and conventional methods. Twenty four (2.6%) of the 904 subcultures grew on the subculture media. The majority (83.3%) of these were determined to be gram-positive microorganisms. Fourteen (58.3%) were coagulase-negative staphylococci, two (8.3%) were Bacillus spp., one (4.2%) was Staphylococcus aureus, and one (4.2%) was identified as Enterococcus faecium. Streptococcus pneumoniae and Neisseria spp. were isolated together in two (8.3%) vials. Gram-negative microorganisms comprised 12.5% of the subcultures, of which two (8.3%) were found to be Pseudomonas aeruginosa, and one (4.2%) was Pseudomonas fluorescens. The other isolate (4.2%) was identified as Candida albicans. We conclude that the subculture of negative results is valuable in the BacT/Alert 3D system, especially in situations in which only one set of blood cultures is taken.     

Eicosanoid synthesis and Helicobacter pylori associated gastritis: increase in leukotriene C4 generation associated with H. pylori colonization.

The importance of pro-inflammatory leukotriene C4 in Helicobacter pylori (H. pylori) associated gastritis in man is unknown. Fresh gastric biopsy specimens from 28 dyspeptic patients were obtained: 10 showed normal antral histology with no evidence of H. pylori, the remaining 18 patients exhibited histological gastritis and were H. pylori positive as assessed by histology, culture and urease test. Twelve of these 18 patients received 240 mg twice daily colloidal bismuth subcitrate for four weeks before re-endoscopy. Gastric biopsies from H. pylori positive patients were incubated under basal and Ca(2+)-ionophore mediated conditions: Radioimmunoassay analysis of the supernatant showed basal release of prostaglandin E2 and leukotriene C4 was slightly but not significantly elevated in H. pylori positive mucosa. However in H. pylori positive mucosa there was an 85% increase in leukotriene C4 synthesis when biopsies were incubated with ionophore, compared to only 13% increase in H. pylori negative mucosa (p less than 0.02). After eradication of H. pylori by colloidal bismuth subcitrate, there was a clearance of inflammatory cell infiltrate as assessed by histology and a significant reduction in ionophore-mediated leukotriene C4 formation compared with before treatment (p less than 0.02). These results suggest that H. pylori gastritis is associated with increased capacity to generate leukotriene C4, which may amplify the damaging effects of the bacteria on gastric mucosa.     

A positive assay for identification of cagA negative strains of Helicobacter pylori

A new PCR protocol was developed for the positive identification of cagA negative Helicobacter pylori strains. Amplification of a portion of the genome across the insertion point of the cag pathogenicity island (the ES-"empty site") generated a 106-bp fragment, which produces a positive signal for cagA negative strains. Combined with the results of the cagA assay, the signals for ES allowed the complete characterization of the patients' cagA status. DNA sequencing analysis confirmed the identity of the ES fragment. The new protocol and cagA assay were applied to 22 DNA preparations isolated from stools from H. pylori infected adult patients and to 21 DNA preparations isolated from stools from H. pylori infected children. The same analysis was also performed on nine colonies of H. pylori derived from gastric biopsies of nine of the adult patients. The total number of cagA positive cases from adult patients was 14 or 63.6% (11 mono- and 3 mixed) and of the cagA negative cases (or ES positive) was 9 or 40.9% (6 mono- and 3 mixed). Of the 21 stool DNA samples from children, 6 (28.6%) were cagA positive, 12 (57.1%) were cagA negative and 3 (14.3%) were positive for cagA and for the ES simultaneously. The proportions of mixed cagA positive and cagA negative H. pylori infections were almost equal in adults and children (13.6% and 14.3%, respectively). No reaction products of the proper fragment sizes for cagA or the empty site (ES) were obtained from any of the stool DNA samples of 10 H. pylori uninfected subjects (100% specificity). This noninvasive assay discriminates consistently cagA negative cases from cagA positive strains and from amplification failures. It can be a useful tool for clinical and epidemiological studies of H. pylori infection.     

Growth of Helicobacter pylori in various liquid and plating media

The objectives of this research were to compare commonly used liquid and plating media to elucidate whether one medium provided superior growth of Helicobacter pylori in vitro. The liquid media compared were Mueller-Hinton broth, brain heart infusion broth and H. pylori special peptone broth, formulated in this laboratory. No significant differences in growth rates were noted and shaking during the incubation of broths was not essential for good growth. The plating media compared included Columbia agar, Mueller-Hinton agar, modified Glupczynski's Brussels campylobacter charcoal agar, Johnson-Murano agar and H. pylori special peptone agar (HPSPA). None of the non-specific plating media that have been used historically to culture H. pylori exhibited any particular advantage. However, HPSPA provided an obvious advantage in colony size. Helicobacter pylori special peptone agar enhances the cultivation of H. pylori and could improve the recovery of the bacterium from clinical samples in vitro.     

Detection of Helicobacter species DNA by quantitative PCR in the gastrointestinal tract of healthy individuals and of patients with inflammatory bowel disease

In many animal species different intestinal Helicobacter species have been described and a few species are associated with intestinal infection. In humans, the only member of the Helicobacter family which is well described in literature is Helicobacter pylori. No other Helicobacter-associated diseases have definitely been shown in humans. We developed a sensitive quantitative PCR to investigate whether Helicobacter species DNA can be detected in the human gastrointestinal tract. We tested gastric biopsies (including biopsies from H. pylori positive persons), intestinal mucosal biopsies and fecal samples from healthy persons, and intestinal mucosal biopsies from patients with inflammatory bowel disease (IBD) for the presence of Helicobacter species. All gastric biopsies, positive for H. pylori by culture, were also positive in our newly developed PCR. No Helicobacter species were found in the mucosal biopsies from patients with IBD (n = 50) nor from healthy controls (n = 25). All fecal samples were negative. Our study suggests that Helicobacter species, other than H. pylori, are not present in the normal human gastrointestinal flora and our results do not support a role of Helicobacter species in IBD.     

手工和仪器两种血培养结果差异性分析

目的对手工法双相血培养瓶和BACTEC9120全自动血培养仪的阳性率作回顾性分析。方法将血液标本同时接种双相血培养基和BACTEC9120全自动血培养仪配套血瓶中,将阳性结果移种血平板,如为阴性再移种巧克力平板。结果370例血培养,双相血培养瓶阳性25例,阳性率为6．76％（25／370）,树脂需氧（儿童）瓶BACTEC9120报警显示阳性59例,阳性率为15．9％（59／370）,阳性标本移种到血平板及巧克力平板阳性54例,阳性率为14．6％（54／370）,假阳性5例,假阳性率为1．4％（5／370）,共有29例树脂需氧（儿童）瓶阳性,而双相血培养瓶为阴性,P〈0．001。结论BACTEC9120全自动血培养仪提高阳性率,缩短阳性的报告时间优于传统的双相血培养基。     

Effect of Helicobacter pylori infection and eradication on gastric epithelial cell proliferation and apoptosis.

OBJECTIVES: the effect of Helicobacter pylori infection on gastric epithelial cell proliferation and apoptosis is still controversial. Our aim was to evaluate the effect of H. pylori infection on cell kinetic parameters in normal gastric epithelium, gastritis with/without intestinal metaplasia and gastric cancer. PATIENTS AND METHODS: antral biopsies were taken from 121 patients (61 women, 60 men, mean age 58.5+/-14.3 years of age) who underwent routine gastroscopy for upper gastrointestinal symptoms. Sections were scored for normal epithelia (n=15), gastritis without intestinal metaplasia (n=74), gastritis with intestinal metaplasia (n=24), and gastric adenocarcinoma (n=8). Fifty-two patients had H. pylori positive gastritis, and success of H. pylori eradication therapy was controlled in 12 cases, all with intestinal metaplasia. To characterize cell proliferation and assess apoptosis, immunohistochemistry [Proliferating Cell Nuclear Antigen (PCNA)], histochemistry [Argyrophil Nucleolar Organizer Regions (AgNOR)], and terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridinetriphosphate (dUTP) nick end-labeling (TUNEL) were used, respectively. RESULTS: both cell proliferation and apoptosis is was higher in chronic gastritis when compared with normal epithelia, but neither PCNA LI (54.79+/-19.1 vs. 53.20+/-20.7) nor AgNOR counts (291.43+/-44.3 vs. 277.8+/-57.54) were different in H. pylori positive versus negative chronic gastritis. A significant positive correlation (P<0.05) was found in this group between PCNA and AgNOR techniques. Apoptosis was significantly higher (P<0.05) in H. pylori positive cases only when intestinal metaplasia was not present. Cell proliferation in intestinal metaplasia decreased to the activity of normal epithelium after successful eradication of H. pylori but remained high if eradication therapy failed. CONCLUSIONS: epithelial cell proliferation does not depend on H. pylori status in chronic gastritis. H. pylori increases apoptosis only in the absence of intestinal metaplasia.     

Comparison of Media for the Enumeration of Clostridium perfringens

For the enumeration of viable vegetative cells and spores of Clostridium perfringens, noncommercial (laboratory prepared) sulfite-polymyxin-sulfadiazine (SPS) agar, tryptone-sulfite-neomycin (TSN) agar, and Shahidi-Ferguson-perfringens (SFP) agar were statistically compared to SPS agar without antibiotics. The selectivities of these four media were also evaluated on the basis of their ability to inhibit the growth of pure cultures of a variety of other organisms. The average recovery of vegetative cells of 10 strains of C. perfringens with SFP agar was not significantly higher than with SPS agar with 10(4) organisms per g, but with 10(6) organisms per g it yielded significantly higher recoveries than SPS agar. TSN agar yielded significantly lower recoveries at both inoculum levels. SFP agar gave significantly higher recoveries of spores than SPS and TSN agars. Average plate counts of spores in SFP agar were 75% as high as in SPS agar without antibiotics, but only 45% of the spores grew in SPS agar and 25% in TSN agar. TSN agar was the most selective of the three media, but the selectivity of SPS agar approached that of TSN agar under the test conditions. SFP agar, which was the least selective of the media, allowed growth to some extent of nearly all of the facultative anaerobes tested.     

Detection of Helicobacter pylori and determination of clarithromycin susceptibility using formalin-fixed, paraffin-embedded gastric biopsy specimens by fluorescence in situ hybridization

BACKGROUND: Clarithromycin resistance and poor compliance to therapy are often responsible for Helicobacter pylori eradication therapy failure. AIM: To evaluate fluorescence in situ hybridization (FISH) as a nonculture method to simultaneously detect H. pylori and to identify clarithromycin resistance. METHODS: Fifty-four patients with dyspepsia (17 male, 37 female subjects; mean age, 46.5; range, 21-78 years) were studied. Two antrum and corpus biopsies were taken from each patient. Positive rapid urease test (RUT) and histopathologic examinations defined H. pylori positivity. A total of 108 formalin-fixed paraffin-embedded gastric mucosal biopsies were examined retrospectively by the FISH (seaFAST H. pylori Combi-Kit) method. RESULTS: Forty-five patients (83.3%) were H. pylori positive and 43 (95.5%) were also positive by FISH. There were two false-positive FISH results. Fourteen patients (31.1%) had clarithromycin-susceptible strains, 4 (8.9%) resistant strains, and 27 (60%) both susceptible and resistant strains. CONCLUSION: FISH results correlated well with H. pylori infection and were able to identify clarithromycin-susceptible and -resistant strains. This technique will be helpful in determining the bacterial density and the success of treatment where clarithromycin has been widely used in populations to increase the efficacy of the treatment and to clarify the treatment failure in vitro.     

Stimulation of the growth of cutaneous strains of Peptococcus saccharolyticus by iron, haematin and blood

The growth of nine strains of Peptococcus saccharolyticus was assessed quantitatively by culture Trypticase Soy/yeast extract/Tween 80 agar (TSY-TW) with and without supplementation with iron or haematin and on blood agar, in aerobic, reduced 02 (3% O2 with 8% CO2, 8% H2 and 81% N2) and anaerobic atmospheres. All strains grew better anaerobically and under reduced O2 conditions than aerobically on supplemented or unsupplemented TSY-TW.Supplementation of TSY-TW with iron or haematin resulted in an average 4.4-fold increase in bacterial count in a reduced O2 atmosphere and an average 4.2-fold increase under anaerobic conditions. Under aerobic conditions the increase in count ranged from O to greater than 5000-fold, as some strains failed to grow on unsupplemented TSY-TW but responded well to the supplements of iron or haematin. The highest bacterial counts were obtained on Columbia blood agar incubated anaerobically. However, P. saccharolyticus failed to grow aerobically on plain or heated Columbia blood agar with or without supplements. TSY-TW blood agar supported the growth of the one strain tested under all three atmospheric conditions. The type strain (ATCC 14953) differed from all others in its failure to grow aerobically or in a reduced O2 atmosphere on supplement or unsupplemented media. Colony size varied greatly on different media, in different atmospheres and from strain to strain, being greatest in a reduced O2 atmosphere on Columbia blood agar. There was no correlation between the viable bacterial count and colony size.     

86例患儿幽门螺杆菌感染情况及其耐药性

目的 了解儿童幽门螺杆菌(H. pylori)感染情况及其耐药性,为儿童H. pylori治疗提供参考信息。 方法 选取2017年1月至2018年10月(男性45例,女性41例)因上消化道不适症状于首都儿科研究所就诊的86名患儿为研究对象,所有患儿行胃镜检查,并使用快速尿素酶试验检测显示H. pylori阳性。入选患儿取胃黏膜样品,使用哥伦比亚琼脂液进行H. pylori培养,阳性培养菌株使用酶生化反应进行鉴定,采用E test法对分离出的H. pylori菌株进行药敏试验。 结果 共分离出H. pylori菌株17株,分离阳性率为19.8%(17/86),其中男性和女性患儿H. pylori阳性率分别为22.2%(10/45)和17.1%(7/41),差异无统计学意义(χ2=0.359,P=0.549)。分离出的17株H. pylori对甲硝唑耐药率最高(70.6%,12/17),其次为克拉霉素(35.3%,6/17)、阿莫西林(23.5%,4/17)、左氧氟沙星(17.6%,3/17)、利福平(11.8％,2/17)和四环素(5.9％,1/17)。其中H. pylori对甲硝唑+克拉霉素双重耐药率为11.8％(2/17);对甲硝唑+阿莫西林双重耐药率为11.8％(2/17);对甲硝唑+左氧氟沙星双重耐药率为5.9％(1/17)。还有1株H. pylori对甲硝唑+克拉霉素+阿莫西林三重耐药,三重耐药率为5.9％(1/17)。 结论 儿科门诊患儿H. pylori感染阳性率较低,其H. pylori菌株对甲硝唑、克拉霉素和阿莫西林耐药率较高,且观察到双重和多重耐药。应提前了解就诊患儿H. pylori感染情况,根据菌株耐药情况选择个体化疗法,以提高根治率,减少菌株耐药性。