The influence of gastric atrophy on Helicobacter pylori antibiotics resistance in therapy-naïve patients.

Background: Antibiotic susceptibility of Helicobacter pylori to antibiotics may vary among different niches of the stomach. The progression of chronic H. pylori gastritis to atrophy changes intragastric physiology that may influence selection of resistant strains. Aim: To study the antibiotic resistance of H. pylori taking the severity of atrophic gastritis in antrum and corpus into account. Methods: Helicobacter pylori-positive patients (n = 110, m = 32, mean age 52.6 ± 13.9 years) without prior H. pylori eradication undergoing upper gastrointestinal (GI) endoscopy for dyspeptic symptoms were included in a prospective study. Patients were stratified into three groups depending on the grade of atrophy: no atrophy (OLGA Stage 0), mild atrophy (OLGA Stage I-II) and moderate/severe atrophy (OLGA Stage III-IV). Two biopsies each from the antrum and the corpus and one from the angulus were taken and assessed according to the updated Sydney system. H. pylori strains were isolated from antrum and corpus biopsies and tested for antibiotic susceptibility (AST) for amoxicillin, clarithromycin, metronidazole, levofloxacin, tetracycline, and rifampicin by the agar dilution methods. A Chi-square test of independence with a 95% confidence interval was used to detect differences in the proportion of patients with susceptible and resistant H. pylori strains. Results: Among 110 patients, primary clarithromycin resistance (R) was 30.0%, both in the antrum and corpus; metronidazole resistance accounted for 36.4 and 34.5% in the antrum and corpus; and levofloxacin was 19.1 and 22.7% in the antrum and corpus, respectively. Resistance rates to amoxicillin, tetracycline, and rifampicin were below 5%. Dual antibiotic resistance rate was 21.8%, and triple resistance rate was 9.1%. There was a significant difference in the resistance rate distribution in antrum (p < 0.0001) and corpus (p < 0.0001). With increasing severity of atrophy according to OLGA stages, there was a significant increase in clarithromycin-R and metronidazole-R. Conclusion: In treatment-naïve patients, antibiotic resistance and heteroresistance were related to the severity of atrophy. The high clarithromycin resistance in atrophic gastritis suggests that H. pylori antibiotic susceptibility testing should always be performed in this condition before selecting the eradication regimen.

Analysis of bacterial distribution and antibiotic resistance in children with severe pneumonia through bronchoalveolar lavage fluid / 中国小儿急救医学

Objective:To realize the bacterial distribution and antibiotic resistance in children with severe pneumonia in this region.Methods:A total of 203 children with severe pneumonia diagnosed in Gansu Provincial People′s Hospital from April 2018 to March 2020 were divided into 0-1, 1-3, 3-7 and 7-14 years old groups.Bronchoalveolar lavage fluid was collected for bacterial culture and identification, and antibiotic susceptibility tests were performed.Results:The positive rate of pathogens was 69.5% (141/203), including 72.3% (102 strains) of Gram-negative bacteria and 30.5%(43 strains)of Gram-positive bacteria.The infection rates were highest in 0-1 years old group and the lowest in 7-14 years old group, which were 45.2%(19/42) and 16.9%(10/59), respectively.The infection rates of Haemophilus influenzae, Escherichia coli and Branhamella catarrhalis in the 1-3 years old group were 30.30%(10/33), 33.33% (11/33), and 21.21% (7/33), respectively, which showed significant differences compared with other groups( P<0.05). The infection rate of Streptococcus pneumoniae in the 0-1 years old group was 42.9%(18/42), which was significantly different compared with other groups ( P<0.001). The resistance rate of Haemophilus influenzae to trimethoprim/sulfamethoxazole was 89.5%(34/38), and the Streptococcus pneumoniae to trimethoprim/sulfamethoxazole and tetracycline were both 82.4%(28/34). The highest antibiotic resistance rate of Escherichia coli was 34.6%(9/26), and the Branhamella catarrhalis to clindamycin was 56.3%(9/16). Conclusion:The dominant bacteria for severe pneumonia in children are Haemophilus influenzae, Streptococcus pneumoniae, Escherichia coli and Branhamella catarrhalis.The bacterial infection rate is highest within 1 year old, but gradually decreases with the increase of age.Haemophilus influenzae and Streptococcus pneumoniae have severe resistance to several antibiotics.

Prevalence and antimicrobial resistance of Shigella flexneri serotype 2 variant in China.

Shigella flexneri serotype 2 variant (II:3,4,7,8) was isolated in 2008 and first reported in China in 2013. In the present study, epidemiological surveillance from 2003 to 2013 in China suggested that this serotype first appeared in Guangxi in 2003; it then emerged in Shanghai and Xinjiang in 2004 and in Henan in 2008. Of the 1813 S. flexneri isolates, 58 S. flexneri serotype 2 variant strains were identified. Serotype 2 variant has emerged as a prominent serotype in recent years, with 2a (32.6%), X variant (25.2%), 1a (9.4%), X (6.3%), 2b (5.4%), and 1b (3.6%). According to phenotypic and genotypic analysis, the serotype 2 variant originated from 2a to 2b. A higher antibiotic resistance rate was observed between 2009 and 2013 than that between 2003 and 2008. Among 22 cephalosporin-resistant isolates, bla TEM-1, bla OXA-1, bla CTX-3, bla CTX-14, and bla CTX-79 were detected. Among 22 fluoroquinolone-resistant isolates, a Ser80Ile mutation in parC was present in all of the isolates. Moreover, 21 isolates had three gyrA point mutations (Ser83Leu, His211Tyr, Asp87Asn, or Gly) and one isolate had two gyrA point mutations (Ser83Leu and His211Tyr). The prevalence of His211Tyr in the fluoroquinolone-resistant isolates is concerning, and the mutation was first reported in China. Besides, 22 isolates harbored the aac(6')-Ib-cr gene, and two isolates harbored qnrS1. In view of the increased epidemic frequency and multidrug-resistant strain emergence, continuous surveillance will be needed to understand the actual disease burden and provide guidance for shigellosis.

Clinical analysis of 214 strains of Staphylococcus aureus from skin and soft tissue infections / 国际检验医学杂志

Objective To investigate the separation rate ,clinical distribution ,antibiotic susceptibility rate of Staphylococcus au‐reus from skin and soft tissue infections and provide the reference for clinical diagnosis and treatment .Methods Retrospective sta‐tistical analysis of 214 strains of Staphylococcus aureus from skin and soft tissue infections from September 2011 to August 2014 by Whonet 5 .6 .Results 1 228 pathogens were isolated from 2 152 cases of the secretion of operative and skin wound ,of which there were 214 strains of Staphylococcus aureus ,which accounted for 17 .43% ,48 strains of MRSA ,which accounted for 22 .43% ;Mainly distributed in bone surgery ,burns orthopaedic ,breast surgery ,with skin venereal division ,accounting for 40 .2% ,22 .3% ,12 .1% , 8 .4% respectively .The resistance rate of Staphylococcus aureus to penicillin ,erythromycin ,clindamycin were 96 .3% ,46 .7% , 37 .4% respectively ,high sensitivity to vancomysin ,linezolid ,fusidic acid ,mupirocin .Conclusion Surgical infection rates of SSTIs are high in our hospital .It should be according to SAU susceptibility analysis results to choose high sensitivity of the first and sec‐ond generation cephalosporins for treatment in clinic ,and vancomycin ,linezolid only in severe Staphylococcus aureus(including MR‐SA) infection to choose .

Clinical features and drug sensitivity of lower respiratory tract infection induced by Streptococcus pneumoniae in children / 临床儿科杂志

Objective To explore clinical features and drug sensitivity of Streptococcus pneumoniae (SP) isolated from pediatric patients with lower respiratory tract infection, and to provide evidence for clinical use of antibiotics. Methods A total of 6 358 clinical SP isolates from children with lower respiratory tract infection from January 2008 to December 2012 were col-lected and retrospectively analyzed. The antibiotic sensitivity was done by Kirby-Bauer method and E-test, and all results were in strict accordance with the rules of CLSI. Results The isolated SP strains were mainly from different departments of pediatrics. All clinical cases with SP infection mainly included pneumonia and bronchitis. The resistance rates of 6 358 SP strains to penicil-lin, cefotaxime, erythromycin, clindamycin, cotrimoxazole, tetracycline, chloramphenicol, levolfoxacin, vancomycin were 5.0%, 12.9%, 98.7%, 96.0%, 92.2%, 7.3%, 5.6%, 0.2%and 0.0%respectively, and the resistance rate to penicillin and cefotaxime was signiifcantly different in every years (all P<0.05). The resistance rates of the 318 penicillin-resistant SP strains to the above anti-biotics were 100.0%, 42.6%, 100.0%, 100.0%, 99.2%, 23.6%, 6.8%, 0.6%, 0.0%respectively, and the resistance rate to penicillin and cefotaxime was signiifcantly different (P=0.001). Conclusions The antibiotic resistance rates of SP strains isolated from children with lower respiratory tract infection were higher to erythromycin, clindamycin, cotrimoxazole and tetracycline, and an increasing rate in drug resistance to cefotaxime was observed in recent years. Appropriate antibiotics should be selected for the treatment of infection according to drug sensitivity.

Analysis of the Antibiotic Resistance Rate of Helicobacter Pylori / 医学研究杂志

Objective To investigate the antibiotic resistance rate of Helicobacter pylori,and to provide reliable evidence of choosing optimal drugs for clinical therapy.Methods Overall 3304 patients were enrolled from February 2006 to March 2007 who accepted gastroscopy followed by Helicobacter pylori culture of the gastric mucosa from biopsy.The antimicrobial susceptibilities of Helicobacter pylori strains for six antibiotics including metronidazole,amoxicilin,gentamycin,levofloxacin,furazolidone,clarithromycin were observed by Kirby-Bauer disk diffusion test.Results 1171(35.4%)biopsy clinical specimens were proved to be Helicobacter pylori positive when cultured in vitro and identified by conventional assays.The metronidazole resistance rate(99.32%)of Helicobacter pylori was significantly higher than that of any of the other 5 antibiotics,and the levofloxacin resistance rate(0.51%)was the lowest.Furthermore there were no significantly change in the tendency of resistance rate for the two above antibiotics from February 2006 to March 2007.However,Helicobacter pylori was resistant to amoxicilin,gentamycin,furazolidone,clarithromycin,and the resistance rate was 61.06%、4.78%、21.35% and 39.45% respectively.Meanwhile,the resistance rates corresponding to four antibiotics were different obviously.Conclusions With the application of antibiotics for Helicobacter pylori eradication,the antibiotic resistance rate increased perceptibly.The rate of resistance to metronidazole appeared to be the highest among six antibiotics applied to clinical treatment.Drug susceptibility testing was valuable to eradicate Helicobacter pylori in clinical therapy.