Threefold Increase in the Number of Drug Resistant TB Cases after Introduction of Universal Drug Susceptibility Testing: Experiences from Two South India Districts

Background: In India, tuberculosis (TB) is a major public health problem, and the advent of drug resistance TB (DR-TB) has worsened the situation. The Revised National TB Control Programme (RNTCP) has introduced universal drug susceptibility testing (UDST) for all diagnosed TB cases in 2018. We conducted this study to know the advantage of implementing UDST when compared to selective testing existent in 2017 on key diagnostic cascade parameters and to identify the challenges in the implementation of UDST. Methods: The study was conducted in two districts of Karnataka, India during January 2017-December 2018. The quantitative part consisted of before-and-after design and the qualitative part consisted of descriptive design. Results: In 2017 (during selective testing/“before” period) out of the 2440 TB patients, 80 (3%) were diagnosed with Isoniazid and Rifampicin resistance patients;in contrast in 2018 (during UDST/“after” period) of the 5129 TB patients 258 (5%) were diagnosed with Isoniazid and Rifampicin resistance. However, the proportion of eligible patients tested for rifampicin resistance during the “after” period was 60% when compared to 100% during the “before” period and median turnaround time for testing was also longer during the “after” period when compared to the “before” period (32.5 days vs 27.5 days). Major reasons for these two gaps were found to be difficulties in collecting sputum specimens and transportation. Conclusion: The rollout of UDST has led to a three-fold increase in a number of DR-TB cases detected in the region. There is a need for the programme to increase the proportion tested for DST by increasing the laboratory capacity and address the challenges in sputum collection and transportation.

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.

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.

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.

Rapid antimicrobial susceptibility testing for mixed bacterial infection in urine by AI-stimulated Raman scattering metabolic imaging

Urinary tract infection with mixed microorganisms may lead to false-positive resistance detection.Current antimicrobial susceptibility testing(AST)performed in clinical laboratories is based on bacterial culture and takes a long time for mixed bacterial infections.Here,we propose a machine learning-based single-cell metabolism inactivation concentration(ML-MIC)model to achieve rapid AST for mixed bacterial infections.Using E.coli and S.aureus as a demonstration of mixed bacteria,we performed feature extraction and multi-feature analysis on stimulated Raman scattering(SRS)images of bacteria with the ML-MIC model to determine the subtypes and AST of the mixed bacteria.Furthermore,we assessed the AST of mixed bacteria in urine and obtained single-cell metabolism inactivation concentration in only 3 h.Collectively,we demonstrated that SRS imaging of bacterial metabolism can be extended to mixed bacterial infection cases for rapid AST.

Isolation,identification,and virulence gene analysis of pathogenic Aeromonas dhakensis in Macrobrachium rosenbergii and histopathological observation

To identify the cause of mass mortality of adult Macrobrachium rosenbergii in a farm in Gaoyou City,Jiangsu Province,China,a dominant strain named DKQ-1 was isolated from the hepatopancreas of dying M.rosenbergii and identified as Aeromonas dhakensis by purification culture,biochemical characterization,and 16S rRNA and gyrB gene sequence analysis.The results of the challenge test revealed that the strain was highly pathogenic and the 50%lethal dose(LD_(50))in 72 h to M.rosenbergii was 1.54×10^(5)CFU/mL.The amplification results of virulence genes show that strain DKQ-1 carried 9 virulence genes,including ascV,aexT,aer,act,lip,ompAI,gcaT,acg,and exu,supporting the strong virulence of strain DKQ-1 to M.rosenbergii.Histopathological observation of the hepatopancreas,gills,and intestines indicated that DKQ-1 injection into M.rosenbergii could cause serious tissue damage,which further supported the strong virulence of this strain.In addition,a drug susceptibility test revealed that strain DKQ-1 was sensitive to 16 kinds of antibiotics,resistant to 9 kinds of antibiotics,and had intermediate resistance to spectinomycin and kanamycin.This study is the first report of A.dhakensis isolated from M.rosenbergii and provided a reference for the pathogen identification of bacterial diseases in M.rosenbergii,and for the prevention and treatment caused by A.dhakensis.

EXTREMELY LOW FREQUENCY MAGNETIC FIELD SUSCEPTIBILITY OF VISUAL DISPLAY UNITS

Extremely low frequency (ELF) magnetic field susceptibility is an index of visual display unit (VDU) quality and performance. This paper provided field measured data on the susceptibility for a large variety of VDUs. A test rig was built to study the susceptibility of VDUs to magnetic fields at fundamental and third harmonic frequencies. It was found that the susceptibility level is largely dependent on refresh rate of the VDU and the orientation of the external ELF field. It was also found that the VDU susceptibility is significantly increased in the presence of harmonic frequency magnetic fields. About 30% of the tested samples have susceptibility levels higher than that stated in IEC 1000-4-8 standard.

A Retrospective Study on the Pyogenic Pathogens and Their Antibiotic Susceptibility Patterns along with the ES<i>β</i>L Production

Pyogenic infections are caused by various pathogens leading to pus formation and that can be attributed due to a wound either through accident or during surgery leading to infection spread. There are pathogenic strains that are not uncommon in hospital settings like Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter etc., that are multidrug resistant (MDR) and are a cause of concern. The bacteriological profile in the pyogenic infections tends to be same but there is a vast difference with the antibiotic resistant patterns in different hospital settings. Hence, the aim was to study the antibiotic susceptibility profiles and Extended spectrum βeta Lactamases (ESβL) production in these pathogens. A prospective study was carried out in Silchar Medical College and Hospital Assam, India, over a four-month period from February to May 2021. The samples were processed using Blood and MacConkey’s agar. Further, these isolated pathogens were identified by standard morphological, cultural and biochemical tests. The antibiotic susceptibility test was conducted by Kirby Bauer disc diffusion method and ESβL production was detected by using combined disk diffusion test. It was observed that the identified pathogens had an incidence rate of 84.2% and further revealed that Gram negative had a higher incidence rate compared to Gram positive with 59.8%. The pathogens isolated from pus samples had a maximum of Klebsiella sps (19.64%) and the lowest was E. coli with 5.36%. Antibiotic susceptibility test (AST) of Gram-negative bacterial isolates showed the highest incidence with aztreonam (40.6%) and the lowest was observed in Piperacillin/Tazobactam with 7.5%. The only Gram positive was observed in our study, Staphylococcus aureus had the highest resistance in amikacin with 80% and interestingly, all the isolates were sensitive to Linezolid with 100%. There is a high rise and spreading with the multi-drug resistance (MDR) strains along with ESβL production and it was observed in our studies that these pathogens had an incidence rate of 18.5%. The highest was 58.1% in Pseudomonas sps. None of Proteus sps were found to be ESβL producers. To combat resistance, the irrational use of antibiotics should be avoided and surveillance of the rising multidrug species regularly helps in implementing better therapeutic options to reduce the morbidity and mortality.

Intraprocedural gastric juice analysis as compared to rapid urease test for real-time detection of Helicobacter pylori

BACKGROUND Endofaster is an innovative technology that can be combined with upper gastrointestinal endoscopy(UGE)to perform gastric juice analysis and real-time detection of Helicobacter pylori(H.pylori).AIM To assess the diagnostic performance of this technology and its impact on the management of H.pylori in the real-life clinical setting.METHODS Patients undergoing routine UGE were prospectively recruited.Biopsies were taken to assess gastric histology according to the updated Sydney system and for rapid urease test(RUT).Gastric juice sampling and analysis was performed using the Endofaster,and the diagnosis of H.pylori was based on real-time ammonium measurements.Histological detection of H.pylori served as the diagnostic gold standard for comparing Endofaster-based H.pylori diagnosis with RUT-based H.pylori detection.RESULTS A total of 198 patients were prospectively enrolled in an H.pylori diagnostic study by Endofasterbased gastric juice analysis(EGJA)during the UGE.Biopsies for RUT and histological assessment were performed on 161 patients(82 men and 79 women,mean age 54.8±19.2 years).H.pylori infection was detected by histology in 47(29.2%)patients.Overall,the sensitivity,specificity,accuracy,positive predictive value,and negative predictive value(NPV)for H.pylori diagnosis by EGJA were 91.5%,93.0%,92.6%,84.3%,and 96.4%,respectively.In patients on treatment with proton pump inhibitors,diagnostic sensitivity was reduced by 27.3%,while specificity and NPV were unaffected.EGJA and RUT were comparable in diagnostic performance and highly concordant in H.pylori detection(κ-value=0.85).CONCLUSION Endofaster allows for rapid and highly accurate detection of H.pylori during gastroscopy.This may guide taking additional biopsies for antibiotic susceptibility testing during the same procedure and then selecting an individually tailored eradication regimen.

Causative Microorganisms Isolated from Patients with Intra-Abdominal Infections and Their Drug Resistance Profiles:An 11-Year(2011–2021)Single-Center Retrospective Study

Objective To investigate the distribution and antimicrobial susceptibility of causative microorganisms recovered from patients with intra-abdominal infections(IAIs).Methods A total of 2,926 bacterial and fungal strains were identified in samples collected from 1,679 patients with IAIs at the Peking Union Medical College Hospital between 2011 and 2021.Pathogenic bacteria and fungi were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.Antimicrobial susceptibility testing(AST)was performed using the VITEK 2 compact system and the Kirby–Bauer method.AST results were interpreted based on the M100-Ed31 clinical breakpoints of the Clinical and Laboratory Standards Institute.Results Of the 2,926 strains identified,49.2%,40.8%,and 9.5%were gram-negative bacteria,gram-positive bacteria,and fungi,respectively.Escherichia coli was the most prevalent pathogen in intensive care unit(ICU)and non-ICU patients;however,a significant decrease was observed in the isolation of E.coli between 2011 and 2021.Specifically,significant decreases were observed between 2011 and 2021 in the levels of extended-spectrumβ-lactamase(ESBL)-producing E.coli(from 76.9%to 14.3%)and Klebsiella pneumoniae(from 45.8%to 4.8%).Polymicrobial infections,particularly those involving co-infection with gram-positive and gram-negative bacteria,were commonly observed in IAI patients.Moreover,Candida albicans was more commonly isolated from hospital-associated IAI samples,while Staphylococcus epidermidis had a higher ratio in community-associated IAIs.Additionally,AST results revealed that most antimicrobial agents performed better in non-ESBL-producers than in ESBL-producers,while the overall resistance rates(56.9%–76.8%)of Acinetobacter baumanmii were higher against all antimicrobial agents than those of other common gram-negative bacteria.Indeed,Enterococcus faecium,Enterococcus faecalis,S.epidermidis,and S.aureus were consistently found to be susceptible to vancomycin,teicoplanin,and linezolid.Similarly,C.albicans exhibited high susceptibility to all the tested antifungal drugs.Conclusion The distribution and antimicrobial susceptibility of the causative microorganisms from patients with IAls were altered between 2011 and 2021.This finding is valuable for the implementation of evidence-based antimicrobial therapy and provides guidance for the control of hospital infections.

Combined antrum and corpus biopsy protocol improves Helicobacter pylori culture success

BACKGROUND Helicobacter pylori(H.pylori)causes chronic gastritis,peptic ulcer disease,gastric adenocarcinoma and mucosa-associated lymphoid tissue lymphoma.Eradication rates have fallen,mainly due to antimicrobial resistance.Consensus guidelines recommend that first-line treatment is based on the local prevalence of antimicrobial resistance and that rescue therapies are guided by antimicrobial susceptibility testing(AST).However,H.pylori culture is challenging and culture-based AST is not routinely performed in the majority of hospitals.Optimisation of H.pylori culture from clinical specimens will enable more widespread AST to determine the most appropriate antimicrobials for H.pylori eradication.AIM To determine whether dual antrum and corpus biopsy sampling is superior to single antrum biopsy sampling for H.pylori culture.METHODS The study received ethical approval from the joint research ethics committee of Tallaght University Hospital and St.James’s Hospital.Patients referred for upper gastrointestinal endoscopy were invited to participate.Biopsies were collected in tubes containing Dent’s transport medium and patient demographics were recorded.Biopsies were used to inoculate Colombia blood agar plates.Plates were incubated under microaerobic conditions and evaluated for the presence of H.pylori.Statistical analyses were performed using Graphpad PRISM.Continuous variables were compared using the two-tailed independent t-test.Categorical variables were compared using the two-tailed Fisher exact test.In all cases,a P value less than 0.05 was considered significant.RESULTS In all,samples from 219 H.pylori-infected patients were analysed in the study.The mean age of recruited patients was 48±14.9 years and 50.7%(n=111)were male.The most common endoscopic finding was gastritis(58.9%;n=129).Gastric ulcer was diagnosed in 4.6%(n=10)of patients,while duodenal ulcer was diagnosed in 2.7%(n=6).Single antrum biopsies were collected from 73 patients,whereas combined antrum and corpus biopsies were collected from 146 patients.There was no significant difference in age,sex or endoscopic findings between the two groups.H.pylori was successfully cultured in a significantly higher number of cases when combined antrum and corpus biopsies were used compared to a single antrum biopsy[64.4%(n=94/146)vs 49.3%(36/73);P=0.04)].CONCLUSION Combined corpus and antrum biopsy sampling improves H.pylori culture success compared to single antrum biopsy sampling.

Comparative Analyses of the Efficacy of Dry and Fresh <i>Mangifera indica</i>Ethanolic Extracts on <i>E. coli</i>and <i>S. aureus</i>

Background: The need to identify and characterize new antimicrobial agents is important due to the increasing development of resistance by microorganisms to the existing antimicrobial agents. Aim: This study examined the efficacies of Mangifera indica on Escherichia coli and Staphylococcus aureus. Method: Three parts (leaf [L], root [R], and bark [B]) of the plant were analyzed. The extraction of the samples was performed by aseptically grinding the samples, dissolving in absolute ethanol, and filtering through whatman filter paper. The efficacy of the extracts bothsingle and combined was determined using agar well diffusion assay with gentamycin [10 μl] (E. coli) and vancomycin [30 μl] (S. aureus) as control antibiotics. Results: The higher concentration (C2 = 3.0 g/ml) showed more antibacterial effectiveness than the lower concentration (C1 = 1.5 g/ml) against both bacterial isolates with significant differences (P < 0.05) in all extracts except for single extracts (E. coli dry leaf extract;fresh bark extract), double extracts (S. aureus: dry and fresh leaf extracts) and triple extract (E. coli and S. aureus dry extracts). For the single extracts the bacteria has the following significant results: E. coli L (dry 6.3 ± 2.5 mm, fresh 14.7 ± 0.6 mm, P = 0.0050), R (dry 11.3 ± 1.5 mm, fresh 7.3 ± 1.5 mm, P = 0.0327);for S. aureus L (dry 7.0 ± 1.7 mm, fresh 11.0 ± 1.0 mm, P = 0.0257), R (dry 7.0 ± 2.0 mm, fresh 11.7 ± 1.5 mm, P = 0.0325), and B (dry 5.0 ± 1.0 mm, fresh 16.0 ± 1.0 mm, P = 0.0002). For the double extracts the bacteria has the following significant results: E. coli L + R (dry 15.7 ± 2.3 mm, fresh 1.7 ± 1.5 mm, P = 0.0070), R + B (dry 18.7 ± 1.5 mm, fresh 9.7 ± 1.5 mm, P = 0.0020), and L + B (dry 9.7 ± 1.5 mm, fresh 6.3 ± 0.6 mm, P = 0.0241);S. aureus L + R (dry 14.7 ± 1.5 mm, fresh 7.0 ± 1.0 mm, P = 0.0019), R + B (dry 15.3 ± 1.5 mm, fresh 11.7 ± 1.5 mm, P = 0.0424). For the triple extracts, the fresh leaves showed significantly higher levels of efficacy than the dry for both E. coli L + R + B (P = 0.0101) and S. aureus (P = 0.0307). The fresh extracts showed higher levels of efficacy than dry extracts against both bacteria for all the single and three combined conditions. Conclusions: Fresh extracts show better efficacies against E. coli while dry extracts show greater efficacies against S. aureus for both single and triple combined extracts. The reverse is true for double combined extracts.

Evidence-Based Use of Antibiotics in Veal Calves with Diarrhea

Diarrhea is the leading cause of mortality in beef and dairy calves during the first week of life and results in substantial financial loss [1]. Diarrhea is a multifactorial disease and can be infectious or non-infectious. However, in the majority of calves, infectious organisms, especially Cryptosporidium parvum, rotavirus, coronavirus, and E. coli, are the primary cause [2]. The aim of this study was to generate a decision tree, based on prevalence, diagnostic testing and treatment and to estimate associated costs or risk. For each of the four main pathogens, two principal approaches are outlined and compared. The first approach relies on a detailed diagnostic workup and allows for specific etiological treatment. The second approach relies on the trial-and-error method, which involves the use of a first-choice antibiotic, followed by a second- and third-choice antibiotic if the previous ones failed to resolve the disease. In Switzerland, the prevalence of diarrheic calves infected with E. coli is approximately 1% suggesting that the use of antimicrobials for the treatment of scouring calves, in the absence of a diagnostic workup, is not always justified. However, for all four major pathogens, the trial-and-error method affords cheaper treatment compared with treatment based on an etiological diagnosis. This creates a quandary in view of the current worldwide efforts to reduce the use of antibiotics in animal agriculture.

Isolation of Pathogenic Gram-Negative Bacteria from Urinary Tract Infected Patients

This study investigated the susceptibility pattern of different bacteria isolated from urinary tract infection to different antibiotics. 83 uropathogen bacteria were isolated from 300 urine samples taken from patients attended to Tikrit Teaching Hospital from March, 2011 through February, 2012. The patients were males and females aged between 4 days to 95 years. Bacteria obtained from urine samples were cultured and tested for antimicrobial susceptibility to 16 kinds of antibiotics. Urine samples were cultured on different media and incubated, thereafter bacteria were isolated and purified by streaking four times on the same media;isolates were identified depending on morphological, microscopic, and biochemical characteristics. The isolated strains of bacteria were tested for their susceptibility to some antibiotics using disk diffusion method. The antagonistic activity was evaluated by observing a clear zone of inhibition growth. The results showed that the bacterial species of Eschericia coli, Proteus mirabilis, Klebsiella pneumonia, Citrobacter diversus, Citrobacter freundii, Enterobacter aerogenes, Yersinia pestis, Pseudomonas aeruginosa, Klebsiella oxytoca and Hafnia alvei were identified in 44 (53%), 18 (21.7%), 4 (4.8%), 4 (4.8%), 3 (3.6%), 3 (3.6%), 3 (3.6%), 2 (2.4%), 1 (1.2%) and 1 (1.2%), respectively, of the isolates. The results of antimicrobial susceptibility test showed that 83 (100%) isolates were resistant to Ampicillin, Rifampicin and Erythromycin. 75 (90.3%) isolates were resistant to Cefotaxime, 67 (80.7%) isolates were resistant to Tobramyci. 66 (79.5%), 65 (78.3%), 56 (67.4%) and 48 (57.8%) isolates showed susceptibility to Nalidixic acid, Tetracycline, Nitrofurantoin, Chloramphenicol, respectively. 45 (54.2%) isolates were resistant to Azithromycin, Norfloxacin and Ciprofloxacin. Meropenem, Gentamicin, Amikacin, and Imipenem show significant effect on 35 (42.1%), 32 (38.5%), 27 (32.5%) and 1 (1.2%) isolates, respectively. In conclusion, significant bacteria count isolated from urine samples is pathogenic. The most effective antibiotic in inhibiting the bacterial growth was Imipenem while Ampicillin, Rifampicin and Erythromycin showed no effect on all 83 isolates (100%).

Isolation and Identification of Bacterial Pathogens of Proteus vulgaris and Chryseobacterium meningosepticum from Peodiscus sinensis and Observation on the Histopathology

Two dominant strains of bacteria Lb18-01 and Lb18-02 were isolated and purified from scabies,liver and intestine of diseased Peodiscus sinensis.By artificial infection test,the two strains were verified as pathogenic strains with similar characters to that of natural infectious cases.The strains Lb18-01 and Lb18-02 showed strong pathogenicity to healthy P.sinensis in the artificial infection experiment,so they were the pathogenic strain of the disease.According to the morphology,physicochemical characteristics,16 S rDNA sequence analysis and phylogenetic tree clustering,the pathogenic strains Lb18-01 and Lb18-02 were identified as Proteus vulgaris and Chryseobacterium meningosepticum which were tolerant to 20 drugs such as penicillin,tetracycline and ampicillin.Histopathological observation on diseased P.sinensis showed the pathological symptoms of sepsis such as hemorrhage and congestion of liver,spleen and intestine,and glomerular disintegration.

Susceptibility-guided bismuth quadruple therapies for resistant Helicobacter pylori infections

Increasing Helicobacter pylori resistance to antibiotics has ledthat molecular testing is appropriate as a sub to adoption of seven different bismuth quadruple therapies(BQT)in China without differentiation of first-line or second-line regimens.The objective of this study was to evaluate the efficacy of susceptibility-guided BQT for patients who had experienced previous treatment failures.A total of 133 patients was included and H.pylori was successfully cultured from 101 patients(75.9%)for subsequent antimicrobial susceptibility testing(AST).Based on the AST results,88 patients completed one of five AST-guided 14-day BQT regimens:esomeprazole and bismuth colloidal pectin,along with either,amoxicillin and clarithromycin(EBAC),amoxicillin and levofloxacin(EBAL),amoxicillin and furazolidone(EBAF),amoxicillin and tetracycline(EBAT),or tetracycline and furazolidone(EBTF).H.pylori eradication rateswere 100%for EBAC(5/5),EBAL(13/13),EBAF(14/14),and EBTF(43/43),but 76.9%for EBAT(10/13).The three patients that failed the EBAT regimenwere all cured after subsequent treatment with the EBTF regimen.Our study demonstrates the excellent efficacy of the AST-guided BQT for referred H.pylori patients,and that the current EBAT regimen,used in clinics,needs to be optimized.In addition,57 of the isolates were subjected to whole-genome sequencing.Analysis of the sequences revealed that point mutations in 23S rRNA correlated well with the phenotypic clarithromycin resistance with a concordance of 91.2%,while the concordance between phenotypic levofloxacin resistance and gyrA point mutations was 82.3%.This suggests that molecular testing is appropriate as a substitute for AST as a more rapid and cost-effective method for determining clarithromycin and levofloxacin resistance in Chinese patients.

Faropenem Susceptibility of Multidrug-resistant Contemporary Clinical Isolates from Zhejiang Province, China

Alternative antimicrobial therapies are urgently needed for a variety of multidrug-resistant bacterial pathogens.Faropenem is an orally available b-lactam in the class of carbapenem antibiotics.Thus far,little information is available on faropenem susceptibility of multidrug-resistant clinical isolates from China.Therefore,in the current study 141 contemporary clinical isolates,including methicillin-resistant Staphylococcus aureus(MRSA:n=18),coagulase-negative staphylococci(CNS:n=16),Enterococcus faecalis(n=14),Enterococcus faecium(n=7),Pseudomonas aeruginosa(n=25),Klebsiella pneumoniae(n=21),Escherichia coli(n=20),and Acinetobacter baumannii(n=20),were collected between March 2018 and March 2019 and tested for susceptibility to faropenem and other antimicrobials using the broth microdilution method.All E.faecium,P.aeruginosa,and A.baumannii isolates were fully resistant to faropenem.However,most of the MRSA,CNS,E.faecalis,K.pneumonia,and E.coli isolates appeared to be susceptible to faropenem,with minimal inhibitory concentration90 values of 4mg/L,2mg/L,2mg/L,4mg/L,and 2mg/L,respectively.Therefore,faropenem could be considered as alternative therapy for future treatment of multidrug-resistant MRSA,CNS,E.faecalis,K.pneumonia,and E.coli infections in China.

Rapid, automated, and reliable antimicrobial susceptibility test from positive blood culture by CAST‐R

Antimicrobial susceptibility tests(ASTs)are pivotal in combating multidrug resistant pathogens,yet they can be time‐consuming,labor‐intensive,and unstable.Using the AST of tigecycline for sepsis as the main model,here we establish an automated system of Clinical Antimicrobials Susceptibility Test Ramanometry(CAST‐R),based on D2O‐probed Raman microspectroscopy.Featuring a liquid robot for sample pretreatment and a machine learning‐based control scheme for data acquisition and quality control,the 3‐h,automated CAST‐R process accelerates AST by>10‐fold,processes 96 paralleled antibiotic‐exposure reactions,and produces high‐quality Raman spectra.The Expedited Minimal Inhibitory Concentration via Metabolic Activity is proposed as a quantitative and broadly applicable parameter for metabolism‐based AST,which shows 99%essential agreement and 93%categorical agreement with the broth microdilution method(BMD)when tested on 100 Acinetobacter baumannii isolates.Further tests on 26 clinically positive blood samples for eight antimicrobials,including tigecycline,meropenem,ceftazidime,ampicillin/sulbactam,oxacillin,clindamycin,vancomycin,and levofloxacin reveal 93%categorical agreement with BMD‐based results.The automation,speed,reliability,and general applicability of CAST‐R suggest its potential utility for guiding the clinical administration of antimicrobials.

Helicobacter pylori infection is an infectious disease and the empiric therapy paradigm should be changed

Helicobacter pylori infection is an infectious disease.Given the alarmingly high antibiotic resistance in H.pylori,gastroenterologists should change the empiric H.pylori treatment paradigm to an antimicrobial susceptibility testing-guided precision treatment.Antimicrobial stewardship programs for H.pylori should be implemented locally,regionally,and nationally to monitor the antibiotic resistance pattern.

Recent advances in droplet microfluidics for microbiology

Advances in microbiology rely on innovations in technology. Droplet microfluidics, as a versatile and powerful technique that allows high-throughput generation and manipulation of subnanoliter volume droplets, has become an indispensable tool shifting experimental paradigms in microbiology. Droplet microfluidics has opened new avenues to various microbiological research, from resolving single-cell heterogeneity to investigating spatiotemporal dynamics of microbial communities, from precise quantitation of microbiota to systematic decipherment of microbial interactions, and from isolating rare and uncultured microbes to improving genetic engineered strains. In this review, we present recent advances of droplet microfluidics in various fields of microbiology: i) microbial cultivation, ii) microorganism detection and characterization, iii) antibiotic susceptibility testing, iv) microbial interactions, v) microbial biotechnology.We also provide our perspectives on the challenges and future directions for droplet microfluidic-based microbiology research.