Rapid bacterial identification and antimicrobial susceptibility testing assay in positive blood cultures / 预防医学

Objective@#To establish a rapid bacterial identification and antimicrobial susceptibility testing assay in positive blood cultures, so as to provide insights into timely diagnosis and treatment of bloodstream infections.@*Methods@#A total of 1 154 blood culture samples were collected from inpatients in Zhejiang Hospital from February to May, 2022. The bacterial isolates were enriched and purified using improved separation gel method, and bacterial identification and antimicrobial susceptibility tests were performed using VITEK2 mass spectrometry system and VITEK2 Compact automated microbiology system. The accuracy of the new assay for bacterial identification and antimicrobial susceptibility tests was evaluated with the conventional VITEK 2 compact system as the standard. @*Results@#Of 1 154 blood culture specimens, the conventional VITEK 2 compact system detected 174 positives and 980 negatives. The new assay and the conventional VITEK 2 compact system identified consistent bacterial isolates in 165 out of 174 positive blood culture samples, and the accuracy of bacterial identification was 94.83% for the new assay, with a 99.21% accuracy for identifying Gram-negative bacteria and 82.22% for Gram-positive bacteria. Antimicrobial susceptibility tests were performed in 158 bacterial isolates, and the new assay presented a 90.17% accuracy, with a 90.27% accuracy for Gram-negative bacteria and 89.74% for Gram-positive bacteria. The conventional VITEK 2 compact system required 30 hours and longer to complete bacterial identification and antimicrobial susceptibility tests, and the new assay required 9 to 18 hours.@*Conclusions@#The new rapid bacterial identification and antimicrobial susceptibility testing assay shortens the time of bacterial culture, achieves rapid bacterial identification and antimicrobial susceptibility testing in blood culture specimens and has a high accuracy that meets clinical needs, which facilitates rapid diagnosis and treatment of bloodstream infections.

Evaluation of rapid identification methods for foodborne diarrhea Campylobacter and detection of drug resistance / 中华检验医学杂志

Objective:To explore and evaluate a appropriate suitable method for detection of Campylobacter and antibiotic sensitivity test for foodborne diarrhea in clinical laboratories. Methods:Pre-experiment:a total number of 400 fecal samples of patients with foodborne diarrhea were prospectively collected from the intestinal disease clinic of Beijing Tongren Hospital from September 2017 to January 2018. Double-hole filtration culture method and modified cefoperazone charcoal deoxycholate (CCD) agar culture method were used for fecal culture in micro-aerobic environment for 48 hours, and then suspicious colonies were identified by matrix assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry. Meanwhile, C. jejuni and C. coli were detected by real-time quantitative polymerase chain reaction(qPCR). Large sample verification: 2 062 fecal samples of patients with foodborne diarrhea in three hospitals of different levels in different areas of Beijing were collected for qPCR detection and culture from April 2018 to March 2019. The antimicrobial sensitivity test (AST) of C. jejuni and C. coli was performed according to the disk diffusion method and agar dilution method recommended by Clinical and Laboratory Standards Institute and National Antimicrobial Resistance Monitoring System for Enteric Bacteria. The results of the three detection methods and the consistency of the two antibiotic sensitivity tests were compared. Results:In the pre-experiment, the positive rates of Campylobacter ( jejuni/coli) detected of qPCR, double-hole filtration culture and modified CCD agar culture were 9.0% (36/400), 5.0% (20/400)and 3.5% (14/400), and the difference was statistically significant ( P<0.01). The samples with negative result of qPCR were negative by both culture methods. The total positive rates of Campylobacter detected by qPCR was 8.1% (168/ 2 062)including 7.0% (144/2 062) for C. jejuni and 1.2% (24/2 062) for C. coli. The samples with positive qPCR results were cultured by double-hole filtration culture method and the positive rate was 61.9%(104/168), among which, the positive rate of C. jejuni and C. coli were 58.3%(84/144) and 83.3%(20/24) respectively, which was not significantly different from the detection rate and culture positive rate in the pre-test ( P>0.1). The resistance rates of C. jejuni and C. coli to ciprofloxacin were 94.0%(94/100) and 100.0%(24/24) and to erythromycin were 6.0%(6/100) and 33.3%(8/24). The results from two antibiotic sensitivity test methods were consistent (Kappa>0.75). Conclusions:qPCR is rapid, sensitive and easy to operate, so it is suitable for routine development in clinical laboratories. The double-hole filtration culture method is beneficial to the acquisition of strains and is essential for the further study of Campylobacter. There was no significant difference between agar dilution method and disk diffusion method in antibiotic sensitivity test. Campylobacter showed a very high resistance rate to quinolones, which was no longer suitable for the treatment of Campylobacter foodborne diarrhea in Beijing area. Macrocyclic lipid antibiotics should be preferred.

Evaluation of in vitro activity of ceftolozane-tazobactam against recent clinical bacterial isolates from Brazil - the EM200 study

ABSTRACT Background: The emergence of antibiotic resistance is increasing and there are few effective antibiotics to treat infections caused by resistant and multidrug resistant bacterial pathogens. This study aimed to evaluate the in vitro activity of ceftolozane-tazobactam against clinical bacterial isolates from Brazil. Methods: A total of 673 Gram-negative bacterial isolates including Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and other Enterobacterales collected from 2016 to 2017 were tested, most of them isolated from patients in intensive care units. Minimum inhibitory concentrations (MIC50/90) were determined by broth microdilution for amikacin, aztreonam, cefepime, cefotaxime, cefoxitin, ceftolozane-tazobactam, ceftazidime, ceftriaxone, ciprofloxacin, colistin, ertapenem, imipenem, levofloxacin, meropenem, and piperacillin-tazobactam using dried panels. Antimicrobial susceptibility results were interpreted according to Clinical and Laboratory Standards Institute criteria. Results: Susceptibility rates to ceftolozane-tazobactam ranged from 40.4% to 94.9%. P. aeruginosa susceptibility rate to ceftolozane-tazobactam was 84.9% (MIC50/90, 1/16 µg/mL) and 99.2% to colistin. For E. coli, ceftolozane-tazobactam inhibited 94.9% (MIC50/90, 0.25/1 µg/mL) of the microorganisms. The susceptibility rate of K. pneumoniae to ceftolozane-tazobactam was 40.4% (MIC50/90, 16/>32 µg/mL). Other Enterobacterales have shown susceptibility rates of 81.1% (MIC50/90, 0.5/16 µg/mL) to ceftolozane-tazobactam, 93.9% to meropenem, 90.9% to amikacin (90.9%), and 88.6% to ertapenem. In non-carbapenemase producing isolates, AmpC mutations were found three isolates. Conclusions: Ceftolozane-tazobactam has shown relevant activity against a large variety of the analyzed microorganisms collected from multiple centers in Brazil, showing promising results even in multidrug resistant strains.

A Study on Burden of Carbapenem-Resistant Pseudomonas aeruginosa and Acinetobacter baumannii Infections in a Tertiary Care Hospital of Eastern India

Introduction: Healthcare associated infections(HAI) bymulti-drug resistant organisms(MDRO) are major cause ofmortality and morbidity having significant impact on qualityof life and economic burden. HAI by carbapenem-resistantPseudomonas aeruginosa (CRPsA) and Acinetobacterbaumannii (CRAB) are emerging threat for their highantibiotic resistance and spread via mobile genetic elements.Objectives of this study were to detect prevalence of CRPsAand CRAB infections in a tertiary care hospital of EasternIndia and to determine their antimicrobial resistance profile.Material and methods: This observational study was done inDepartment of Microbiology from January 2018-June 2019.From HAI patients, different clinical samples were collected.Culture and identification by standard conventional methodsand antimicrobial susceptibility tests by modified KirbyBauer disc-diffusion method following CLSI guidelines wereperformed. CRPsA and CRAB cases were identified whenisolates were resistant to ≥1 carbapenem, 10µg imipenemdisc(zone diameter ≤15mm for P. aeruginosa or ≤18mm forA. baumanii) or meropenem disc (≤15mm for P. aeruginosa or≤14mm for A. baumanii).Result: From 27,043 clinical samples, 1785(6.6%)Acinetobacter baumannii and 777(2.87%) Pseudomonasaeruginosa were isolated. CRAB and CRPsA prevalencewere 74.17% and 62.29% respectively. Carbapenemresistance were further categorised into imipenem-resistantmeropenem-resistant (IRMR) (A. baumanii-63.19%, P.aeruginosa-51.61%), imipenem-resistant-meropenemsensitive (IRMS) (A. baumanii-10.48%, P. aeruginosa-9.13%), meropenem-resistant-imipenem-sensitive (MRIS)(A. baumanii -0.51%, P. aeruginosa -1.54%) phenotypes.Fourth category was imipenem-sensitive-meropenemsensitive (ISMS) (A. baumanii -25.82%, P. aeruginosa-37.71%). Carbapenem-resistant groups showed significantlyhigh resistance for all antibiotics excepting colistin.Conclusion: Carbapenems are often used for treatingMDRO. But high carbapenem-resistance in HAI is alarming,warranting judicious use of antibiotics.

Trends in Bloodstream Infections and Antimicrobial Susceptibilities at a University Hospital in Korea Between 2007 and 2016

BACKGROUND: Blood culture is an important method for identifying infectious microorganisms and confirming that a selected antimicrobial treatment is appropriate. In this study, we investigated the annual changes in the frequencies of blood isolates and antibiotic susceptibility test (AST) results. METHODS: We created a large database comprising data on all patient-unique blood cultures obtained from January 2007 through December 2016. Blood specimens were cultured using the BD BACTEC FX system, and species identification and AST were performed using the VITEK 2 system. RESULTS: During the 10-year study period, a total of 203,651 blood culture results were collected. Of these, gram-positive cocci, gram-negative rods, and fungi were isolated in 2.15%, 0.55%, and 0.12% of the blood cultures, respectively. Escherichia coli was the most commonly isolated species (22.8%), followed by Staphylococcus epidermidis (16.8%), Klebsiella pneumoniae (8.1%), and Staphylococcus aureus (8.0%). Fungal species were isolated in 3.0% of all positive blood cultures. Candida albicans was the most commonly isolated species (1.1%), followed by Candida parapsilosis (0.6%). Methicillin resistance was seen in 55.2% of S. aureus isolates. The frequencies of vancomycin-resistant Enterococcus (VRE) and carbapenem-resistant Pseudomonas aeruginosa (CRPA) were 13.1% and 10.9%, respectively. The isolation rates of MRSA, VRE, and CRPA showed different patterns each year. CONCLUSIONS: Among the isolates, E. coli was the most common, followed by S. epidermidis and K. pneumoniae. This study represents a long-term analysis of bloodstream infections, and the results can be used to identify trends in the microorganisms isolated and their drug resistance.

Investigation and analysis of infection and antibiotic resistance of Helicobacter pylori in armed policemen in Shaanxi province / 解放军医学杂志

Objective To investigate and analyze the situation of Helicobacter pylori (Hp) infection and antibiotic resistance in armed police officers and soldiers (APOSs) in Shaanxi province, and provide a theoretical basis for the rational selection of drugs for the eradication of Hp in the armed police forces in this region. Methods Two hundred and three APOS patients from the Shaanxi Armed Police Corps Hospital who underwent gastroscopy for gastrointestinal symptoms from June 2016 to December 2017 were enrolled in this study. Biopsy samples were extracted by gastroscope and Hp was isolated, identified and cultured. Four types of antibiotics were used to analyze the sensitivity of resistance to drugs: amoxicillin, clarithromycin, levofloxacin and metronidazole. Results A total of 119 Hp strains were isolated from 203 endoscopic biopsies. The positivity rate was 58.6%. The positivity rate of Hp isolation and culture in patients with peptic ulcer was 58.1% (36/62), which was significantly higher than that in patients with chronic gastritis (35.2%, 32/91, χ2=7.832, P=0.005); There was no statistical difference compared with other pathological types of diseases (P>0.05). The resistance rates of Hp to amoxicillin, clarithromycin, levofloxacin, and metronidazole were 1.7% (2/119), 10.1% (12/119), 14.3% (17/119) and 28.6% (34/119), respectively. There were 12 of 119 strains were detected to be resistant to two drugs, of them 7 were resistant to clarithromycin and metronidazole, and 5 were resistant to levofloxacin and clarithromycin. We did not find the strains which are antibiotic resistant to three or more drugs. There was no significant difference in Hp resistance between different pathological disease types (P>0.05). Conclusions The role of Hp in the development of peptic ulcers among local armed police officers is very important. The current first-line therapy should be selected for eradication treatment of APOS patients in the region.

Pathologic and microbiologic aspects of pet psittacine infected by Escherichia coli and Salmonella Typhimurium / Aspectos patológicos e microbiológicos de Psittaciformes de companhia infectados por Escherichia coli e Salmonella Typhimurium

The role of Escherichia coli in healthy microbiota of psittacine is controversial, and the presence of Salmonella sp. indicates possible disease. Therefore, this study aimed to identify the presence of E. coli and Salmonella spp. in a psittacine pet that died in Fortaleza, Brazil, correlating pathogenicity aspects of the isolates through the evaluation of lesions and antimicrobial susceptibility. Psittacine pets sent to the Laboratory of Ornithological Studies, State University of Ceará, that died in 2014 and 2015 were necropsied. Fragments of liver, kidneys, intestine, lung, heart, spleen and brain were collected for microbiological and histopathological analyses. Scores were attributed to lesions and isolated strains submitted to antimicrobial susceptibility test. From the seventy necropsied birds, nineteen were positive for E. coli and one for Salmonella Typhimurium. Congestive lesions and lymphoplasmocitic inflammatory infiltrate were observed varying from light to moderate and were the main findings. In the analyzed strains, multidrug resistance against different groups of antibiotics was observed. In conclusion, according to the results, E. coli strains and the Salmonella Typhimurium isolate produced significant lesions in the psittacine pets, and multidrug resistance may hinder treatments with antibiotics used in avian pet medicine.(AU)

A participação de Escherichia coli na microbiota saudável de Psicittaciformes e a de Salmonella spp. já indica possível doença. O objetivo deste estudo foi pesquisar a presença de E. coli e Salmonella spp. em psittaciformes de companhia na cidade de Fortaleza/Ceará, traçando os aspectos de patogenicidade destas cepas através das lesões e da sensibilidade antimicrobiana. Foram necropsiados os psittaciformes de companhia encaminhados ao Laboratório de Estudos Ornitológicos da Universidade Estadual do Ceará durante o período de 2014 a 2015. No momento da necropsia foram coletados fragmentos de fígado, rins, intestino, pulmão, coração, baço e encéfalo para posterior processamento microbiológico e histopatológico. As lesões foram graduadas e as cepas isoladas submetidas a antibiograma. Das setenta aves necropsiadas, dezenove foram positivas para E. coli e apenas uma para Salmonella Typhimurium. As lesões de congestão e infiltrado inflamatório linfoplasmocitário variaram de leve a moderado, e foram as principais lesões encontradas. Nas cepas analisadas foi constatada multiresistência a diferentes grupos de antibióticos testados. De acordo com os achados, pode-se concluir que os isolados de E. coli e Salmonella Typhimurium produziram lesões significativas em psittaciformes em Fortaleza, Brasil, e a multirresistência pode dificultar o tratamento com antibióticos usados na clínica de aves de companhia.(AU)

Preliminary exploration of redesigning positive blood culture specimen processing flow / 上海交通大学学报（医学版）

Objective·To directly detect the bacteria in positive blood culture specimens by the separation gel tube combined with MicroflexTM matrixassisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS),perform direct antimicrobial susceptibility test based on the results of mass spectrometry,and preliminary explore the redesign of conventional positive blood culture specimen processing flow.Methods·449 positive-alarm blood culture specimens of monobacterial infections in clinical microbiology laboratory of Xirhua Hospital affiliated to Shanghai Jiao Tong University School of Medicine from September 1,2015 to August 31,2016 were collected and prepared according to the new positive blood culture specimens processing flow.The new redesigned processing flow included smear staining and microscopy,separation gel/mass spectrometry direct identification,bacteria film/mass spectrometry identification,pure colony/mass spectrometry identification,direct antimicrobial susceptibility test,and conventional antimicrobial susceptibility test,etc.According to the results of microscopic examination,identification test,and antimicrobial susceptibility test,level Ⅰ direct microscopic examination report,positive blood culture level Ⅱ (direct identification/bacteria film identification or direct antimicrobial susceptibility) report,and level Ⅲ final report were provided sequentially.Results·With the new redesigned processing flow,bacterial specieslevel identification reports for 82.2％,95.8％,and 100％ of positive blood samples could be obtain at 10 am and 17 pm on the current day and 10 am in the next morning,respectively,and be sent to clinical departments.Initial antimicrobial susceptibility reports for the bacteria that were considered as clinical significant pathogens by preliminary assessment could be provided in the next day of blood culture positive alarm with a higher coincidence rate as compared to the results of traditional antimicrobial susceptibility tests.Conclusion·The time from blood culture positive alarm to the provision of initial identification and antimicrobial susceptibility reports is shorter by 1-2 d for the redesigned processing flow than for the traditional one,which can provide fast and accurate etiologic diagnosis evidence for bloodstream infections for clinicians and is important for improving early diagnosis and treatment of clinical bloodstream infections.

Serotypes and antimicrobial resistance profile of the Group B Streptococcus isolates in perinatal pregnant women during the period from 2013 to 2014 / 中国感染与化疗杂志

Objective To analyze the serotypes and antimicrobial susceptibility profile of Group B Streptococcus (GBS) in perinatal pregnant women.Methods The vaginal and rectal specimens were collected from pregnant women at 35 to 37 weeks of pregnancy for culture and identification.The serotypes were analyzed using agglutination assay.Antimicrobial susceptibility testing was conducted by using Kirby-Bauer method,and interpreted according to 2009 CLSI breakpoints.The data were analyzed via WHONET 5.6 software.Results The prevalence of GBS was 10.4％ (264/2 533) in the 2 533 perinatal pregnant women.Serotype Ⅲ,Ⅰa and Ⅰb was identified in 54.9％ (84/153),17.6％ (27/153) and 13.1％ (20/153) of the GBS,respectively.All the GBS isolates were susceptible to penicillin,cefiriaxone and vancomycin.But 32.9％,68.1％ and 62.1％ of the isolates were resistant to levofloxacin,erythromycin and clindamycin,respectively.The antibiotic resistance rate of serotype Ⅲ isolates to the above three antibiotics was significantly higher than the other serotypes.Conclusions GBS may colonize both vagina and rectum of pregnant women.Vaginal and rectal secretions should be sampled simultaneously for better screening GBS.GBS serotype Ⅲ was the predominant serotype.Penicillin can be used as the first-choice treatment for GBS infections in pregnant women and newborns.GBS-positive pregnant women should be given the intervention treatment immediately to ensure the health of perinatal infants.

Recent Trends in Methicillin-resistant Staphylococcus aureus Infection and Antibiotic Treatment in Staphylococcal Scalded Skin Syndrome in Patients in Childhood: A Single-center Study / 대한피부과학회지

BACKGROUND: Staphylococcal scalded skin syndrome (SSSS) is a blistering disease of superficial skin mediated by Staphylococcus aureus (S. aureus) exfoliative toxin. Generally, SSSS affects mainly infants and children younger than 5 years and has a good prognosis. However, an increasing number of cases of methicillin-resistant S. aureus (MRSA) have been reported recently. OBJECTIVE: The purposes of this study were to evaluate the clinical features and course, to investigate the microbiological manifestations, and to perform antimicrobial susceptibility testing of SSSS among Korean children. METHODS: From March 2003 to July 2016, a total of 141 children were included in this study. The patients were divided into two different groups according to time of onset of their disease: before or after September 2011. We retrospectively reviewed medical records, microbiological results, bacterial detection sites, and antimicrobial susceptibility tests of all participating children. The results of comparison between the two groups were evaluated using the chi-square test. RESULTS: S. aureus infections were identified in all patients. Among all cultured S. aureus specimens, 63.1% (89/141) showed methicillin resistance. Beginning in September 2011, MRSA infection showed a significantly higher prevalence than that previously demonstrated (71.7% vs. 38.8%; p=0.0010). Moreover, MRSA infections were detected on the skin and neck and in the nose (each detected on 61, 41, and 18 occasions, respectively) with overlap observed in many cases. CONCLUSION: In conclusion, since the prevalence of MRSA infection has been gradually increasing in recent years, careful consideration is needed in the selection of antibiotics covering MRSA.

Change of pathogens in patients with biliary tract infection treated in a single center during the past 30 years / 中华肝胆外科杂志

Objective To investigate the changes of pathogens and antimicrobial susceptibility in patients with biliary tract infection during the past 30 years.Methods During the periods of 1981-1984,1988-1998 and 2003-2013,each 100 patients treated with common bile duct exploratoration were selected from every period.Biopsied bile specimens were performed with bacteria culture and antimicrobial susceptibility tests.This study reviewed the changes in bilary pathogens and antimicrobial susceptibility test.Results From 1981 to 1984,the most common pathogens were Escherichia coli (59.2％) and Klebsiella pneumonia (28.9％).Mixed infection of these pathogens accounted for 16.9％.From 1988 to 1998,the types of pathogens significandy increased.Escherichia coli (33.1％) and Klebsiella pneumonia (16.5％) accounted for less than 50％.Mixed infection with Escherichia coli and Pseudomonas aeruginosa was the most common type.From 2003 to 2013,gram-negative bacteria were still the main pathogens,accounting for 61.8％.Escherichia coli and Pseudomonas aeruginosa accounted for 20.1％ and 10.4％,respectively.Gram-positive bacteria increased sigrnificantly.Enterococcusfaecium (22.2％) ranked the first.Mixed infection increased (36％),of which more than 50％ was mixed pathogens of Escherichia coli and Enterococcusfaecium.The incidence of fungi infection also increased (5.6％).Conclusions There was a remarkable change of pathogen category in the biliary infections over the past years.With an increase of gram-positive bacteria and fungi infection in clinical practice,antimicrobial susceptability results could be considered in choosing appropriate drug to avoid bacterial resistance.

Prevalence and antibiotic resistance proifle ofHelicobacter pylori in Shanghai / 中国感染与化疗杂志

Objective To examine the prevalence ofHelicobacter pylori in Shanghai and relevant risk factors, evaluate the resistance proifle ofH. pylori isolates to antibiotics used in ifrst-line therapy in two hospitals in Shanghai.MethodsH. pylori were isolated from the biopsy samples of gastric mucosa collected from September 2013 to January 2015. Antimicrobial susceptibility test was performed by E-test method for 131H. pylori strains to 4 antibiotics, clarithromycin, metronidazole, amoxicillin and tetracycline. Results A total of 955 patients receiving gastroscopy were enrolled. And 248 (26.0%)H. pylori strains were isolated from the biopsy samples of gastric mucosa. Overall, 14.5%, 64.1%, 0 and 0.8% of the strains were resistant to clarithromycin, metronidazole, amoxicillin and tetracycline, respectively. Resistance to two drugs was found in 10.7%(14/131) of the strains, and majority (92.8%, 13/14) of which were resistant to clarithromycin and metronidazole.Conclusions The prevalence ofH. pylori in gastric mucosa is rather lower compared with the data reported previously. It is associated with the sex, age and clinical outcome of patients, however, antibiotic resistance profile is not related to these factors.H. pylori eradication therapy should be individualized according to the results of susceptibility test in Shanghai.

Research Review on Antifungal Drug Resistance Mechanisms in Candida Spp / 现代检验医学杂志

In recent years,the epidemiology of Candida infection has changed.Although Candida albicans is still the main pathogens causing invasive candidiasis,non-albicans Candida species are increasingly encountered.Different Candida species show distinct sensitivity of different drugs.The emergence of drug resistance has become the main problem of Candida in-fection treatment.Antifungal resistance of clinical Candida infections often lead to treatment failure.The review of resistance mechanisms and the effect on clinical treatment is very significant to improve the prognosis of patients and strengthen the control of infection.This text reviews the present state of the detection of mechanisms of resistance in Candida spp .

Surveillance on the etiology and molecular epidemiology of Shigella sonnei isolated in Henan province from 2011 to 2014 / 中华流行病学杂志

Objective To detect and analyze the distribution of virulence factors,antimicrobial resistance and pulsed field gel electrophoresis (PFGE) patterns of Shigella sonnei,isolated in Henan province from 2011 to 2014.Methods Samples of diarrhea patients were collected and isolated with SS selective culture medium in 37 ℃ for 18-24 hours.All strains were identified under the Kligler iron agar/motility-indol-urea biochemical action and API20E biochemical system.Serological typing and prepared DNA template were carried out with thermal cracking method and multiplex PCR,to detect the virulence genes of Shigella sonnei.According to the molecular typing method and K-B drug susceptibility testing method published by the international PulseNet bacterial infectious disease monitoring network and USA clinical and Laboratory Standards Institute,antimicrobial susceptibility tests and PFGE molecular characteristics of these positive strains isolated from sentinel hospitals patients stool samples were analyzed.Results Among the 98 strains of Sonnei type Ⅰ and 118 strains of Sonnei type Ⅱ,all the strains carried carry different virulence genes including SHET-1B,SHET-2,ial,ipaH genes,with 4 kinds of virulence gene combination types.All the 216 strains of Shigella sonnei belonged to the multi-drug resistant strains,including 34 isolates resistant to 2-4 kinds of antibiotics (15.7％),147 isolates to 5-8 kinds of antibiotics (68.1％),24 to 9-10 kinds of antibiotics (11.1％),7 to 11 kinds of antibiotics (3.2％),and 4 to 13 kinds of antibiotics (1.9％).A total of 100 strains of Shigella sonnci were divided into 31 molecular patterns,digested by Xba Ⅰ and PFGE.Each pattern contained 1-13 strains with similarities ranged from 68.6％-100.0％.Conclusions All the Shigella sonnei strains carried virulence pathogenic factors,presenting serious status on drug resistance.PFGE fingerprinting patterns showed high polymorphism and dominant characteristics.PFGE patterns of partial strains and corresponding antidrug spectrum presented certain relevance and with same aggregation relationship.

MOLECULAR IDENTIFICATION AND ANTIMICROBIAL RESISTANCE PATTERN OF SEVEN CLINICAL ISOLATES OF Nocardia spp. IN BRAZIL / Identificação molecular e perfil de sensibilidade a antimicrobianos de sete isolados clínicos de Nocardia spp. no Brasil

Nocardia is a ubiquitous microorganism related to pyogranulomatous infection, which is difficult to treat in humans and animals. The occurrence of the disease is on the rise in many countries due to an increase in immunosuppressive diseases and treatments. This report of cases from Brazil presents the genotypic characterization and the antimicrobial susceptibility pattern using the disk-diffusion method and inhibitory minimal concentration with E-test® strips. In summary, this report focuses on infections in young adult men, of which three cases were cutaneous, two pulmonary, one neurological and one systemic. The pulmonary, neurological and systemic cases were attributed to immunosuppressive diseases or treatments. Sequencing analysis of the 16S rRNA segments (1491 bp) identified four isolates of Nocardia farcinica, two isolates of Nocardia nova and one isolate of Nocardia asiatica. N. farcinica was involved in two cutaneous, one systemic and other pulmonary cases; N. nova was involved in one neurological and one pulmonary case; and Nocardia asiatica in one cutaneous case. The disk-diffusion antimicrobial susceptibility test showed that the most effective antimicrobials were amikacin (100%), amoxicillin/clavulanate (100%), cephalexin (100%) and ceftiofur (100%), while isolates had presented most resistance to gentamicin (43%), sulfamethoxazole/trimethoprim (43%) and ampicillin (29%). However, on the inhibitory minimal concentration test (MIC test), only one of the four isolates of Nocardia farcinica was resistant to sulfamethoxazole/trimethoprim.

Nocardia é um microorganismo ubiquitário relacionado a infecções piogranulomatosas, com difícil resolução tecidual em humanos e animais. A doença é mundialmente emergente devido ao aumento de doenças e tratamentos imunossupressores. Este relato de casos ocorridos no Brasil visa apresentar a identificação molecular dos isolados e o padrão de sensibilidade a antimicrobianos por disco-difusão e concentração inibitória mínima (CIM) através de fitas E-test®. Os casos ocorreram em homens, em idade adulta. Três quadros foram cutâneos, dois pulmonares, um neurológico e um sistêmico. O quadro respiratório, o neurológico e um sistêmico estavam associados à doença ou terapia imunossupressoras. O sequenciamento do gene 16S rRNA (1491pb) possibilitou a identificação de quatro isolados de Nocardia farcinica, dois de Nocardia nova e um de Nocardia asiatica. N. farcinica foi observada em dois casos dermatológicos, um pulmonar e um quadro sistêmico, N. nova foi isolada de um caso neurológico e outro pulmonar; e N. asiatica em um caso dermatológico. O teste de disco-difusão mostrou que amicacina (100%), amoxicilina/clavulanato (100%), cefalexina (100%) e ceftiofur (100%) foram mais efetivos; enquanto gentamicina (43%), sulfametoxazol/trimetoprim (43%) e ampicilina (29%) foram menos efetivos. No entanto, no teste de concentração inibitória mínima (CIM), apenas um dos quatro isolados da espécie Nocardia farcinica mostrou-se resistente a sulfametoxazole-trimetropina.

Bacterial isolates and in vitro antimicrobial susceptibility in blepharitis / 中华实验眼科杂志

Background Blepharitis is an induce factor for multiple ocular surface diseases.Research showed that bacteria play an important role in the pathogenesis of blepharitis.To make sure the pathogenic bacteria and effective antimicrobial agents are of clinical significance for the prevention and treatment of blepharitis.Objective The purpose of this study was 1o investigate the bacterial isolates of conjunctival sac secretion and meibomian secretion in the patients with blepharitis and study their in vitro antimicrobial susceptibility.Methods Forty-five patients with anterior blepharitis and 45 cases with posterior blepharitis were included in Beijing Chaoyang Hospital from December 2006 to December 2012,and 45 patients for laser in situ keratomileusis were enrolled in the same period as control group.The secretions of the conjunctival sac and meibomian were collected with sterile cotton swab,and bacterial isolates were cultured in bouillon culture-medium.The number of eyes with different bacteria was examined and calculated.Then the bacteria were switched to blood agar plates,and antimicrobial susceptibility test to erythromycin,gentamicin,tobramycin,rifampin,levofloxacin were performed by M ueller Hinton (M-H) medium paper method.Results The total germiculture positive rates were 81.1％,76.1％ and 65.0％ in the anterior blepharitis group,posterior blepharitis group and the control group,showing a significant difference among them (x2 =12.80,P=0.00).The germiculture positive rates in meibomian secretion were 84.4％ and 78.8％ in the anterior blepharitis group and the posterior blepharitis group,which were significantly higher than 67.8％ in the control group (x2=7.30,P =0.03).There was no statistically significant difference in the germiculture positive rate of conjunctival sac section among the three groups (77.8％,73.3％ and 62.2％) (x2 =5.60,P=0.06).The main bacteria in conjunctival sac secretion and meibomian secretion were staphylococcus epidermidis,staphylococcus aureus and corynebacterium in all the subjects,but streptococcus pneumoniae and gram-negative bacillus were not detected in the control group.Staphylococcus showed the highest susceptibility to gentamicin,tobramycin and rifampicin,with the sensitive rate ＞70％.Corynebacterium was susceptible to various drugs.Streptococcus pneumoniae had susceptibility to erythromycin and tobramycin.However,Gram-negative bacillus was not susceptible to all the drugs above.Conclusions Bacteria participate in the pathogenesis of blepharitis,but the germiculture positive rate,bacterial species and drug susceptibility of bacteria are obviously different between patients with blepharitis and normal population.Reasonable application of antimicrobial agents is important to blepharitis.

Analysis of bacterial drug susceptibility of common enterobacteriaceae in pediatric patients / 国际检验医学杂志

Objective To summarize the bacterial drug susceptibility of common enterobacteriaceae in pediatric patients and the epidemic status of the extended spectrum beta‐lactamases(ESBLs) during 2013 and 2014 in our hospital in order to guide the clini‐cal application of antibacterial drugs .Methods Routine methods of isolation and culture were performed and the distribution of en‐terobacteriaceae with resistance were statistically analyzed with the software .Results A total of 530 isolates were collected in the hospital in which was 32 .08% Klebsiella pneumonia and 38 .87% Escherichia coli .The most sensitive drug of Enterobacteriaeeae was carbapenems .ESBLs positive rate in Escherichia coli and Klebsiella pneumonia were 32 .04% and 20% .The difference was sta‐tistically significant (P<0 .05) .Conclusion Escherichia coli and Klebsiella pneumonia were the common enterobacteriaceae in pedi‐atric patients .Carbapenems remained very high activity against Enterobacteriaceae .However ,the carbapenems resistance strains have been appeared that should pay attention .Antibiotic therapy should be based on the guidance of bacteriology to select sensitive drugs .

Analysis of multi-resistant organisms in the hospital during the past 4 consecutive years / 国际检验医学杂志

Objective To investigate the change trend and the drug resistance rate of the multi-resistant organisms in the hospi-tal during the past four years,so as to guide the clinical medication,and strengthen the management of antibiotics application.Meth-ods Kirby-Bauer test which was recommended by the clinical and laboratory standards institute was used to conduct the suscepti-bility test,with the results evaluated based on US Clinical and Laboratory Standards Institute.Results Strains of bacteria were de-tected from January 201 1 to December 2014 in each year for the basic trend.The gram-negative bacterium was in the dominant posi-tion.The bacteria in the top five were:Escherichia coli,Staphylococcus epidermidis,Staphylococcus aureus,Pseudomonas aeruginosa and Pneumonia crayresearch coli.In each year,the overall situation of bacteria distribution had little changed.From the antimicrobial susceptibility test results,425 strains of multi-resistant bacteria were detected during the past four years.The detection rate and constituent ratio of multi-resistant bacteria then fell slightly in the first three years,but rebound in 2014.There was no statistically significant difference between the four years.Conclusion In the past four years,our hospital actively participates in monitoring and controlling the multiple drug-resistant bacteria,but nosocomial infection of the multiple drug-resistant bacteria has not been effec-tively controlled because of a variety of factors.We should continue to strengthen monitoring the clinical multiple drug-resistant bacteria,and understand the change tendency.In order to strengthen the management of the use of antibiotics and to guide clinical rational drug use,the drug sensitive test and the resistance situation of the hospital should be considered for the reasonable selection of antimicrobial agents.Strengthening the biological monitoring of clinical departments,enhancing the consciousness of sterile oper-ation of clinicians can help prevent the spread of drug-resistant strains.

Establishing Quality Control Ranges for Antimicrobial Susceptibility Testing of Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus: A Cornerstone to Develop Reference Strains for Korean Clinical Microbiology Laboratories

Quality control (QC) processes are being performed in the majority of clinical microbiology laboratories to ensure the performance of microbial identification and antimicrobial susceptibility testing by using ATCC strains. To obtain these ATCC strains, some inconveniences are encountered concerning the purchase cost of the strains and the shipping time required. This study was focused on constructing a database of reference strains for QC processes using domestic bacterial strains, concentrating primarily on antimicrobial susceptibility testing. Three strains (Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus) that showed legible results in preliminary testing were selected. The minimal inhibitory concentrations (MICs) and zone diameters (ZDs) of eight antimicrobials for each strain were determined according to the CLSI M23. All resulting MIC and ZD ranges included at least 95% of the data. The ZD QC ranges obtained by using the CLSI method were less than 12 mm, and the MIC QC ranges extended no more than five dilutions. This study is a preliminary attempt to construct a bank of Korean QC strains. With further studies, a positive outcome toward cost and time reduction can be anticipated.

Annual Report on External Quality Assessment Scheme in Clinical Microbiology in Korea (2013) / 임상검사와정도관리

Annual external quality assessment was performed three times for clinical microbiology division of The Korean Association of Quality Assurance for Clinical Laboratory. For each trial, three sets composed of different combinations of four bacteria and one yeast were distributed for culture, identification, and antimicrobial susceptibility tests. A total of 340 laboratories were enrolled and 330 (97.0%), 331(97.4%), and 331(97.4%) returned the results on trial I, II, and III, respectively. For bacterial identification, the correct identification of gram-negative bacilli, Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus capitis, Streptococcus agalactiae, Listeria monocytogenes, and Candida species was greater than 95%. However, correct identification of Staphylococcus lugdunensis, Corynebacterium striatum, Vibrio vulnificus, Aeromonas hydrophila, Cryptococcus neoformans, and Malassezia pachydermatis was relatively less accurate, with values of 95.4%, 89.9%, 50.7%, 91.3%, 93.6%, and 93.9%, respectively. Surveillance cultures for vancomycin-resistant enterococci and methicillin-resistant S. aureus were correctly determined by 95.4% and 93.9% of the respondents, respectively. False carbapenem-resistance due to AmpC beta-lactamase, disk diffusion testing for vancomycin in Staphylococcus species, oxacillin and penicillin susceptibility testing in S. lugdunensis and false imipenem-resistance in Proteus species were common sources of inaccurate results. The accuracy of species identification for Corynebacterium species and Vibrio species requires improvement. Consistent problems occurred with antimicrobial susceptibility testing of vancomycin for Staphylococcus species using the disk diffusion method.