Antimicrobial susceptibility testing for Helicobacter pylori in times of increasing antibiotic resistance

The gram-negative bacterium Helicobacter pylori(H.pylori)causes chronic gastritis,gastric and duodenal ulcers,gastric cancer and mucosa-associated lymphoid tissue lymphoma.Treatment is recommended in all symptomatic patients.The current treatment options for H.pylori infection are outlined in this review in light of the recent challenges in eradication success,largely due to the rapid emergence of antibiotic resistant strains of H.pylori.Antibiotic resistance is a constantly evolving process and numerous studies have shown that the prevalence of H.pylori antibiotic resistance varies significantly from country to country,and even between regions within the same country.In addition,recent data has shown that previous antibiotic use is associated with harbouring antibiotic resistant H.pylori.Local surveillance of antibiotic resistance is warranted to guide clinicians in their choice of therapy.Antimicrobial resistance is assessed by H.pylori culture and antimicrobial susceptibility testing.Recently developed molecular tests offer an attractive alternative to culture and allow for the rapid molecular genetic identification of H.pylori and resistance-associated mutations directly from biopsy samples or bacterial culture material.Accumulating evidence indicates that surveillance of antimicrobial resistance by susceptibility testing is feasible and necessary to inform clinicians in their choice of therapy for management of H.pylori infection.

Detection of Beta-Lactamase and Extended-Spectrum Beta-Lactamase of Pathogens Isolated from Pig and Chicken and Their Antibiotic Susceptibility Test

The antibacterial activity of beta-lactam antibiotics or their combinations with inhibitor sulbactum against non-lactamase- producing strains, lactamase-producing and ESBLs-producing isolates was evaluated with twofold dilution method after pathogens isolated from pigs and chickens were detected, respectively, for beta-lactamase and extended-spectrum beta- lactamases （ESBLs）, The results revealed that most of 43 clinically isolated strains could produce beta-lactamase and 3 strains of shigella isolated from chicken samples produced ESBLs. All of 30 lactamase-producing strains isolated and only one of 16 non-lactamase-producing strains were resistant to amoxicillin and ampicillin. MICs of ampicillin against lactamaseproducing isolates decreased 10-40 and 10-20 times respectively, when it was conbined with sulbactam at ration of 1：2 and 1：4. All clinical isolates were susceptible to third-generation cephalosporins. The MICs of third-generation cephalosporins against lactamase-producing isolates did not change when they were conbined with sulbactam. MICs of ceftiofur and ceftriaxone against ESBLs-producing isolates decreased 2-4 times when they were conbined with sulbactam.

Isolation,Identification and Antibiotics Susceptibility Test of Citrobacter freundii from Procambarus clarkia

This experiment was conducted to clarify species and drug resistance of pathogen from the diseased Procambarus clarkia. Pathogenic bacteria from hepatopancreas of the diseased P. clarkia were examined using conventional methods,and then were isolated. The further tests and analysis of the isolated strain were developed,including the regression experiment to P. clarkia,the morphology,physiological and biochemical characteristics,sequence analysis of their 16 S rRNA and gyr B genes,and the susceptibility test to antibiotics. Large colonies with similar morphology and color were obtained. Strain X120523 was identified as Citrobacter freundii,proved to have strong pathogenicity,and was susceptible to quinolones and aminoglycosides.

Antibiotic Susceptibility Patterns of Isolated Bacteria from Otitis Media in Children at Mohamed Aden Sheikh Children Teaching Hospital in Hargeisa, Somaliland

Background: Otitis media (OM) is a group of inflammatory diseases of the middle ear. OM is a prevailing problem among children in Hargeisa. The antibiotic susceptibility of etiologic bacteria is not investigated in Somaliland which hinders the effective treatment of OM cases in children. Objective: This study aimed at determining the etiologic bacteria and its antibiotic susceptibilities in children presenting with OM to a pediatric referral hospital in Hargeisa for the period March 2013-May 2017. Methods: A cross-sectional retrospective study was conducted on a random sample of 270 children with OM. The laboratory used standard microbiological techniques for bacterial isolation and Kirby Bauer disk diffusion method for antibiotic susceptibility testing. Data were entered and analyzed using Epi Info 7 and any associations among the study variables tested with Chi2 test with confidence level of 95% and p value of Results: The rate of bacterial isolation was 96.3%. The predominant bacterial isolate was S. aureus (31.48%) followed by P. aeruginosa (24.81%) and P. mirabilis (15.93%) respectively while the least prevalent isolates were coagulase negative Staphylococcus (1.48%), S. pyogenes (0.74%) and Enterobacter spp. (0.37%) in descending order. Age group 0 - 3, χ2 (143,270 = 223.245, p = 0.000) showed highest bacterial isolation. There was no significant relationship between bacterial isolate and gender, χ2 (11,270 = 9.2283, p = 0.6008). S. aureus showed highest sensitivity towards ciprofloxacin (85.7%), amikacin (76.5%), and gentamicin (73.8%). All isolates showed mixed resistance pattern. Conclusion: S. aureus, P. aeruginosa and P. mirabilis were the leading causative pathogens of otitis media. No association was established between isolate distribution and gender. Both the isolated gram-positive and gram-negative bacteria showed greatest sensitivity towards ciprofloxacin while the highest resistance was observed to penicillins, tetracyclines and sulfonamides. The Otitis Media among children in Hargeisa could be possibly treated, based on the antibiogram of the major associated bacteria, with topical and systemic formulations of the following antibiotic groups: fluoroquinolones, aminoglycosides and 3rd gen. cephalosporins.

Causative bacteria of ventilator-associated pneumonia in intensive care unit in Bahrain:Prevalence and antibiotics susceptibility pattern

BACKGROUND Ventilator-associated pneumonia(VAP)is defined as pneumonia that occurs two calendar days following endotracheal intubation or after that.It is the most common infection encountered among intubated patients.VAP incidence showed wide variability between countries.AIM To define the VAP incidence in the intensive care unit(ICU)in the central gove-rnment hospital in Bahrain and review the risk factors and the predominant bacterial pathogens with their antimicrobial susceptibility pattern.METHODS The research was a prospective cross-sectional observational study over six months from November 2019 to June 2020.It included adult and adolescent patients(>14 years old)admitted to the ICU and required intubation and mechanical ventilation.VAP was diagnosed when it occurred after 48 h after endotracheal intubation using the clinical pulmonary infection score,which considers the clinical,laboratory,microbiological,and radiographic evidence.RESULTS The total number of adult patients admitted to the ICU who required intubation and mechanical ventilation during the study period was 155.Forty-six patients developed VAP during their ICU stay(29.7%).The calculated VAP rate was 22.14 events per 1000 ventilator days during the study period,with a mean age of 52 years±20.Most VAP cases had late-onset VAP with a mean number of ICU days before the development of VAP of 9.96±6.55.Gram-negative contributed to most VAP cases in our unit,with multidrug-resistant Acinetobacter being the most identified pathogen.CONCLUSION The reported VAP rate in our ICU was relatively high compared to the international benchmark,which should trigger a vital action plan for reinforcing the implementation of the VAP prevention bundle.

A comparative study on antimicrobial susceptibility of uroculturome of humans in health and urinary tract infections

Background:The uroculturome indicates the profile of culturable microbes inhabiting the urinary tract,and it is often required to do a urine culture to find an effective antimicrobial to treat urinary tract infections(UTIs).Methods:This study targeted to understand the profile of culturable pathogens in the urine of apparently healthy(128)and humans with clinical UTIs(161)and their antimicrobial susceptibility.All the urine samples were analyzed to quantify microbial load and determine the diversity and antimicrobial susceptibility of microbes following standard microbiological methods.Results:In urine samples from UTI cases,microbial counts were 1.2×10^(4)±6.02×10^(3) colony-forming units(cfu)/mL,while in urine samples from apparently healthy humans,the average count was 3.33±1.34×10^(3) cfu/mL.In eight samples(six from UTI cases and two from apparently healthy people,Candida(C.albicans 3,C.catenulata 1,C.krusei 1,C.tropicalis 1,C.parapsiplosis 1,C.gulliermondii 1)and Rhizopus species(1)were detected.Candida krusei was detected only in a single urine sample from a healthy person and C.albicans was detected both in urine of healthy and clinical UTI cases.Gram-positive(G+ve)bacteria were more commonly(Odds ratio,1.98;CI99,1.01-3.87)detected in urine samples of apparently healthy humans,and Gram-negative(G−ve)bacteria(Odds ratio,2.74;CI99,1.44-5.23)in urines of UTI cases.From urine samples of 161 UTI cases,a total of 90 different types of microbes were detected and,73 samples had only a single type of bacteria.In contrast,49,29,3,4,1,and 2 samples had 2,3,4,5,6 and 7 types of bacteria,respectively.The most common bacteria detected in urine of UTI cases was Escherichia coli(52 samples),in 20 cases as the single type of bacteria,other 34 types of bacteria were detected in pure form in 53 cases.From 128 urine samples of apparently healthy people,88 types of microbes were detected either singly or in association with others,from 64 urine samples only a single type of bacteria was detected while 34,13,3,11,2 and 1 sample yielded 2,3,4,5,6 and seven types of microbes,respectively.In the urine of apparently healthy humans too,E.coli was the most common bacteria,(10 samples)followed by Staphylococcus haemolyticus(9),S.intermedius(5),and S.aureus(5),and similar types of bacteria also dominated in cases of mixed occurrence,E.coli was detected in 26,S.aureus in 22 and S.haemolyticus in 19 urine samples,respectively.G+ve bacteria isolated from urine samples’irrespective of health status were more often(P<0.01)resistant than G−ve bacteria to ajowan oil,holy basil oil,cinnamaldehyde,and cinnamon oil,but more susceptible to sandalwood oil(P<0.01).However,for antibiotics,G+ve were more often susceptible than G−ve bacteria to cephalosporins,doxycycline,and nitrofurantoin.Conclusion:The study concludes that to understand the role of good and bad bacteria in the urinary tract microbiome more targeted studies are needed to discern the isolates at the pathotype level.Further,the study suggests the use of antibiotics by observing good antibiotic stewardship following antibiotic susceptibility testing only.

Assessment of Clinical Presentation, Performance of Diagnostic Methods and Antibiotic Susceptibility Testing for Salmonella among Patients Attending Kangema Sub-County Hospital, Kenya

Background: Typhoid disease remains a major public health problem globally, especially in developing countries in sub-Saharan Africa. Symptoms associated with typhoid disease mimic those of other febrile illnesses and are thus difficult to make an accurate diagnosis. A confirmed diagnosis requires the determination or isolation of the bacteria in well-equipped laboratories. Developing countries are faced with a huge limitation of the laboratory infrastructure to diagnose typhoid disease, which would otherwise guide in treating, managing, controlling, and halting the spread of drug resistant mutants. Objective: This study, therefore, was aimed at determining the clinical presentation, performance of diagnostic tests and antibiotic susceptibility testing of Salmonella among adults attending Kangema Sub-County Hospital. Study Population: The study population was residents of Kangema Sub-County in Murang’a County, Kenya while the target population was adults. Methods: The study adopted a cross-sectional study design that employed a systematic random sampling procedure. The study took place between April and June 2021. The sample size was 97 respondents who all consented and were enrolled in the study. Interviewing the respondents was carried out by administering structured questionnaires to collect quantitative data. Stool samples were obtained and cultured in Cary Blair transport media and then cultured in appropriate media at the Murang’a County Referral Hospital Laboratory. A rapid Salmonella Antigen (SAT) test was also performed on all the stool samples. Data Analyses: Word Statistics and Data (STATA) v 13 was used for statistical analysis. Results: The prevalence of Typhoid Fever was at 6.2% (95% CI) which included S. Typhi (n = 1;16.7%) and S. Paratyphi B (n = 5;83.3%). No isolate showed resistance to Ciprofloxacin. The sensitivity of SAT is 100% and a specificity of 98.9% with a kappa statistic of almost perfect agreement (0.9641) with culture. Patients who had fever p = 0.001, abdominal distention p = 0.028, diarrhoea p = 0.038, loose or watery stool p = 0.021 and mild general condition p = 0.02 remained independently associated with Salmonella infection. Conclusion: Typhoid Fever being endemic, laboratory diagnosis was a key for confirmation after clinical diagnosis. SAT can accurately be used to detect the disease where culture is unavailable. However, antibiotic sensitivity tests were crucial when determining the drug of choice as Salmonella isolates were multi-drug resistant. Establishment of prescribing antimicrobial policies and guidelines can periodically monitor the antibiogram patterns.

Research Progress of Radical Treatment of Helicobacter Pylori Based on Drug Sensitivity Test as First-Line Treatment

Helicobacter pylori (HP) infection is a global problem that affects about half of the world’s population and requires sufficient attention in clinical and scientific work. Due to differences in economic and medical conditions among countries around the world, there is currently no unified treatment plan for anti-HP. In China, empirical quadruple therapy is mainly used. With the abuse of antibiotics, many patients face the problem of secondary eradication after failure, and the resistance rate of HP is gradually increasing. After eradication failure, drug sensitivity cultivation is carried out to choose sensitive antibiotics for treatment. A new strategy is currently needed to address how to improve the eradication rate of HP during the first eradication. This article aims to discuss the first-line treatment plans and research progress for eradicating HP based on drug sensitivity testing before eradication. Compared with traditional empirical therapies, treatment based on drug sensitivity results can effectively improve the eradication rate of HP, and reduce drug resistance rates, and adverse reactions, among other benefits. .

Identification and Susceptibility Test of Ralstonia solanacearum Isolated from White Burley

[ Objective ] The paper was to isolate and identify Ralstonia solanacearum from white burley, and determine its susceptibility to 6 fungicides. [ Mcth- od] Using the combination method of semiselective medium （PCCG） and apolymerase chain reaction （PCR） technique, R. solanacearum in stalk of white burley from Dazhou City in Sichnan Province was isolated, and its biochemical type was identified. Through susceptibility test, the susceptibility of R. solanacearum to bismerthiazol, ethylicin, streptomycin, lime sulfur, 47% polylysine, 99% kojic acid was studied in laboratory. [Result] A total of 23 strains OfR. solanacearum were isolated, all belonging to biochemical type Ill. R. solanacearum obtained in the test were more susceptible to ethylicin, streptomycin and bismerthiazol, and ethylicin had good control effect against R. solanacearum with ECso of 0.086 ml/L. [ Conclusion ] The study provide theoretical basis for control of R. solanaceanon in white burley.

Is the Potential Interconnection between Antibiotic Susceptibility and Disinfectant Resistance a Threat to Food Safety?

The prevalence of antibiotic susceptibility and disinfectant resistance in bacterial pathogens causes a serious problem not only to food safety but also to public health, which directly or indirectly leads to treatment and disinfection failures. In this review, multidrug resistance, the mechanism of disinfectant resistance, the methods for detecting disinfectant resistance and the cross-resistance between an- tibiotics and disinfectants are summarized. More efforts should be devoted to explor- ing the professional guidance of using antibiotics and disinfectants, and to develop- ing the comprehensive detection with genetic and molecular methods is highly ex- pected.

Different antibiotic susceptibility between antrum and corpus of the stomach,a possible reason for treatment failure of Helicobacter pylori infection

AIM: To assess whether antibiotic resistance varies between the antrum and corpus of the stomach of patients that are either Helicobacter pylori (H. pylori) therapy-naive or pre-treated.

Biochemical characters and antibiotic susceptibility of Staphylococcus aureus isolates

Objective:To observe the biochemical characters and antibiotic susceptibility of isolated Staphylococcia aureus(S.auerus) strains against some conventional and traditional antibiotics. Methods:Thirty post operative pathogenic isolated S.aureus strains were used in this study. Bacterial culture was done in Mueller-Hinton broth at 37 ℃.Characters of these strains were determined by traditional biochemical tests such as hydrolysis test of gelatin,urea,galactose, starch and protein,and fermentation of lactose and sucrose.Antibiotic susceptibility were carried out by minimum inhibilory concentration test,minium bactericidal concentration test,disc agar diffusion test and brain heart infusion oxacillin screening agar.Results:Prom this study,it was observed that 100%S.aureus isolates showed positive results in gelatin,urea and galactose hydrolysis test.50%isolates were positive in starch hydrolysis test,35%in protein hydrolysis test. 100%isolates in lactose fermenting test,but no isolate was positive in sucrose fermenting test. Antibiotic susceptibility testing suggested that 20%of isolates were resistant to kanamycin and 46.67%were resistant to oxacillin.Conclusions:These findings show that all these isolates have gelatin,urea,galactose hydrolysis and lactose fermenting activity.20%of these isolates were resistant to kanamvcin and 46.67%were resistant to oxacillin.

Bile anaerobic bacteria detection and antibiotic susceptibility in patients with gallstone

OBJECTIVE: To detect bile anaerobic bacteria and antibiotic susceptibility in 59 patients with gallstoneswho had had cholecystectomy.METHODS: BACT/ALERT 120 microbe detection system and SCEPTOR microbe detection system wereused to detect bile anaerobic bacteria, antibiotic susceptibility.RESULTS: The ratio of anaerobic bacteria to the patients examined was 52.5% (31/59). Obligateanaerobe bile culture showed positive results in 4 patients. B. fragilis (37.8%) was the major type ofanaerobic bacteria in bile. Most (81.8%) of anaerobic bacteria were sensitive to metronidazole, andimipenem was suitable for β-lactamase bacteria.CONCLUSIONS: Culture of anaerobic bacteria in logarithmic phase can improve the positive rate of theculture. There are some relations between anaerobic infection and gallstone formation.

Breath and string test: A diagnostic package for the identification of treatment failure and antibiotic resistance of Helicobacter pylori without the necessity of upper gastrointestinal endoscopy

AIM: Helicobacter pylori (H pylori) resistance after failed eradication has a major impact on the outcome of a further treatment regimen. The aim of this study was to assess the validity of a non-invasive strategy using the 13C-urea breath test (UBT) and the gastric string test in identifying post-treatment resistance of H pylori. METHODS: The UBT was routinely performed 4 to 6 wk after H pylori eradication therapy. Forty-two patients (24 females, 18 males, mean age 48 years) with a positive UBT were included in the study. A gastric string test using a capsule containing a 90 cm-long nylon fiber was performed. Before the capsule was swallowed, the free end of the string was taped to the cheek. After one hour in the stomach, the string was withdrawn. The distal 20 cm of the string was inoculated onto an agar plate and processed under micro-aerophilic conditions. Following the string test, upper gastrointestinal endoscopy was performed to obtain gastric biopsies for conventional culture. RESULTS: H pylori was successfully cultured from the gastric string in 34 patients (81%), but not in 5 patients due to contamination with oropharyngeal flora. H py/oriwas cultured from the gastric biopsies obtained at endoscopy in 39 patients (93%). CONCLUSION: The UBT followed by the gastric string test in the case of treatment failure is a valid diagnostic strategy with the aim of determining the post-therapeutic antibiotic resistance of H pylori with little inconvenience to the patient. Upper Gl-endoscopy can be avoided in several cases by applying consequently this diagnostic package.

Antibiotic susceptibility profiling and virulence potential of Campylobacter jejuni isolates from different sources in Pakistan

Objective:To determine antibiotic resistance patterns and virulence potential of Campylobacter jejuni(C.jejuni) isolates from clinical human diarrheal infections,cattle and healthy broilers.Methods:Antibiotic sensitivity patterns of C.jejuni isolates were determined by Kirby Bauer Disc Diffusion assay.These isolates were then subjected to virulence profiling for the detection of map A(membrane-associated protein).cadF(fibronectin binding protein).wlaN(beta-1.3-galaclosyltransferase) and neu AB(sialic acid biosynthesis gene).Further C.jejuni isolates were grouped by random amplification of polymorphic DNA(RAPD) profiling.Results:A total of436 samples from poultry(n=88).cattle(n=216) and humans(n=132) from different locations were collected.Results revealed percentage of C.jejuni isolates were 35.2%(31/88).25.0%(54/216) and 11.3%(15/132) among poultry,cattle and clinical human samples respectively.Antibiotic susceptibility results showed that similar resistance patterns to cephalothin was ie.87.0%,87.1%and 89%among humans,poultry and cattle respectively,followed by sulfamethoxazolc+trimcthoprim 40.0%,38.7%and 31.0%in humans,poultry and cattle and Ampicillin 40%,32%and 20%in humans,poultry and cattle respectively.Beta-lactamase activity was detected in 40.00%humans.20.37%cattle and 32.25%in poultry C.jejuni isolates.CadF and mapA were present in all poultry,cattle and human C jejuni isolates.wlauN was not detected in any isolate and neu AB was found in 9/31(36%) poultry isolates.RAPD profiling results suggested high diversity of C.jejuni isolates.Conclusions:Detection of multidrug resistant C.jejuni strains from poultry and cattle is alarming as they can be potential hazard to humans.Moreover,predominant association of virulence factors,cadF and map A(100%each) in C.jejuni isolates from all sources and neuAB(36%) with poultry isolates suggest the potential source of transmission of diverse types of C.jejuni to humans.

Breath test for differential diagnosis between small intestinal bacterial overgrowth and irritable bowel disease:An observation on non-absorbable antibiotics

AIM： To estimate the prevalence of small intestine bacterial overgrowth （SIBO） among patients with an earlier diagnosis of irritable bowel disease （IBS） in our geographical area, and to collect information on the use of locally acting non-absorbable antibiotics in the management of SIBO. METHODS： A non-interventional study was conducted in 73 consecutive patients with a symptom-based diagnosis.. RESULTS： When the patients underwent a ＂breath test＂, 33 （45.2%） showed the presence of a SIBO. Arcer treatment with rifaximin 1200 mg/d for seven days in 32 patients, 19 （59.4%） showed a negative ＂breath test＂ one week later as well as a significant reduction of symptoms, thus confirming the relationship between SIBO and many of the symptoms claimed by patients. In the other 13 patients, ＂breath test＂ remained positive, and a further cycle of treatment with ciprofloxacin 500 mg/d was given for 7 additional days, resulting in a negative ＂breath test＂ in one patient only. CONCLUSION： （1） about half of the patients with a symptomatic diagnosis of IBS have actually SIBO, which is responsible for most of the symptoms attributed to IBS; （2） only a ＂breath test＂ with lactulose （or with glucose in subjects with an intolerance to lactose） can provide a differential diagnosis between IBS and SIBO, with almost identical symptoms; and （3） the use of non-absorbable antibiotics may be useful to reduce the degree of SIBO and related symptoms; it must be accompanied, however, by the correction of the wrong alimentary habits underlying SIBO.

Importance of antimicrobial susceptibility testing for the management of eradication in Helicobacter pylori infection

The management of Helicobacter pylori(H. pylori) infection treatment differs from the common treatment protocol for other infectious diseases. Because culture-or molecular-guided approaches face several practical issues, such as the invasive procedures required to obtain gastric biopsy specimens and the lack of availability of routine laboratory testing in some places, H. pylori treatment includes the administration of two or three empirically selected antibiotics combined with a proton pump inhibitor rather than evidence-based eradication treatment. The efficacy of empirical therapy is decreasing, mostly due to increasing multiple resistance. Multiresistance to levofloxacin, clarithromycin, and metronidazole, which are commonly used in empirical treatments, appears to have increased in many countries. Mutations play a primary role in the antimicrobial resistance of H. pylori, but many different mechanisms can be involved in the development of antibiotic resistance. Determining and understanding these possible mechanisms might allow the development of new methods for the detection of H. pylori and the determination of antimicrobial resistance. A treatment based on the detection of antimicrobial resistance is usually more effective than empirical treatment. Nevertheless, such an approach before treatment is still not recommended in the Maastricht guidelines due to the difficulty associated with the routine application of available cultureor molecular-based susceptibility tests, which are usually administered in cases of treatment failure. The management of first and rescue treatments requires further research due to the steadily increase in antimicrobial resistance.

Oblique Y-groove cracking test of the welding cold cracking susceptibility of domestic X-70 pipeline steel

Gas Transmitting From West to East Project' is significant. It should ensure the welding quality and safety of pipeline. The task is very arduous to guarantee the quality of the project in the condition of long line, complex weather and geology features. In this paper, the welding cold cracking susceptibility of domestic X 70 pipeline steel adopted by the project, which is one of the most interesting questions of welding quality about petrol pipeline, was studied by means of oblique Y groove cracking test. The crack ratio of surface and section was tested under the conditions of different welding materials and preheat temperature .The thickness of plate steel was 14.7 mm and 10.3 mm . The results reveal that X 70 pipeline steel has good crack resistance. The research has important value for the construction of large scale pipeline engineering and the application of domestic X 70 pipeline steel.

Drug Susceptibility Test of Volatile Oil of Artemisiaargyi to Avian Pathogenic Escherichia coli

The volatile oil of Artemisia argyi was extracted by ultrasonic assisted extraction, and the extraction rate of volatile oil was 0.68%. Thevolatile oil of A. argyi was emulsified with 1% Tween-80, and drug susceptibility test was conducted with avian Escherichia coli. The results showedthat the volatile oil of A. argyi had antibacterial effect against avian E. coli, and the minimal inhibitory concentration was 50 mg/mL. Taking sixcommon antibiotics as the control, drug susceptibility test was conducted with volatile oil of A. argyi. The results showed that 10 strains of E. coliwere sensitive to the volatile oil of A. argyi, three of which had different degrees of resistance and one had the tendency of resistance.

Expert Consensus on Polymyxin Antimicrobial Susceptibility Testing and Clinical Interpretation

The polymyxins are important antimicrobial agents against antibiotic-resistant gram-negative bacilli.In 2020,the Clinical and Laboratory Standards Institute modified the clinical breakpoints for polymyxin susceptibility test by eliminating the"susceptible"interpretive category,only reporting intermediate(≤2 mg/L)and resistant(≥4 mg/L).However,the European Committee on Antimicrobial Susceptibility Testing recommended the use of clinical breakpoints of W2 mg/L as susceptible and>2 mg/L as resistant.The first-line laboratorians and clinicians in China have been perplexed by the inconsistence of international polymyxin clinical breakpoints and discouraged by the difficulty of conducting polymyxin susceptibility testing.Therefore,it is urgently needed to make it clear for the laboratorians in China to know how to accurately carry out polymyxin susceptibility testing and standardize the interpretation of susceptibility testing results.To this end,the experts from relevant fields were convened to formulate this consensus statement on the testing and clinical interpretation of polymyxin susceptibility.Relevant recommendations are proposed accordingly for laboratorians and clinicians to streamline their daily work.