In vitro susceptibility of fosfomycin in uropathogens with emerging resistance in Enterococcus isolates

Background: Urinary tract infection is a very common clinical entity and are the leading causes of nosocomial infections. The options for antibiotics especially for nosocomial infections are very limited. Fosfomycin a good drug to be used in UTI and is recommend as first line agents for acute uncomplicated UTIs. The emergence of resistance to fosfomycin is a concern. Limited resistance data for fosfomycin is available from India. This study was conducted in order to monitor the trends of resistance to fosfomycin in E coli and Enterococcus faecalis causing UTI. Methods: Urine samples received in the laboratory from all patients were included in the study. Microscopy of uncentrifuged urine sample was done. Culture and sensitivity was done as per the CLSI guidelines. Susceptibility testing of the isolates to fosfomycin was performed interpretation done as per CLSI. Results: Total 150 isolates were taken for the study which included 100 isolates of E. coli and 50 isolates of Enterococcus faecalis. None of the E. coli isolates were resistant to fosfomycin and 82.0% of the isolates were found to be sensitive to nitrofurantoin. None of the Enterococcus faecalis isolates were resistant to linezolid. The percentage susceptibility was 52 % and 70 % for nitrofurantoin and fosfomycin respectively. Conclusions: The increasing resistance to fosfomycin is a matter of concern. An increased fosfomycin resistance rate in E. faecalis was observed. Performing antimicrobial susceptibility testing should be the most important criteria before starting the antibiotic to avoid undue usage and more such studies need to be conducted.

Prevotella bloodstream infection:a 10-year single-center retrospective study / 中国感染控制杂志

Objective To improve clinicians'understanding on Prevotella bloodstream infection(BSI),reduce the rate of misdiagnosis and missed diagnosis,and broaden the ideas of diagnosis and treatment.Methods Clinical data of patients with Prevotella BSI at a hospital affiliated to a medical school of Nanjing University from May 2013 to May 2023 were collected.Risk factors,sources of infection,strains of infection,clinical manifestations,laboratory test results,treatment,and outcomes of patients with Prevotella BSI were retrospectively analyzed.Results A to-tal of 23 patients diagnosed with Prevotella BSI were included in analysis,15(65.2％)were males and 8(34.8％)were females.Most patients had related predisposing factors before BSI,such as surgical procedures(n=11,47.8％),malignant tumors(n=10,43.5％),diabetes(n=9,39.1％),and indwelling urinary catheter(n=10,43.5％),etc.There were 9 types of infected bacteria,mainly Prevotella buccalis(n=6,26.1％),Prevotella bivia(n=5,21.7％)and Prevotella intermedia(n=4,17.4％).The main sources of infection were hepatobiliary system(n=6,26.1％),abdominal and thoracic cavities(n=4,17.4％),as well as urogenital tract(n=4,17.4％).All pa-tients showed symptoms of chills and fever,with significantly elevated blood inflammation indicators.Four cases(17.4％)developed septic shock,and 18 cases(78.3％)had a good prognosis after appropriate anti-infection treat-ment.Conclusion When atypical BSI caused by Prevotella is suspected,predisposing factors should be removed as soon as possible,blood should be actively collected and performed culture,rational use of antimicrobial agents based on antimicrobial susceptibility testing is beneficial for rapid control of infection and improvement of prognosis.

Molecular Detection of Enterotoxigenic Staphylococcus aureus in Ready-to-eat Cowhide (‘Ponmo’) Collected from Lagos Metropolis, Nigeria

Aims: Ready-to-eat [RTE] animal products like ponmo are preferred by consumers due to its palatability and quality. However, foodborne pathogens particularly Staphylococcus aureus are sources of concern due to cross-contamination of raw and cooked cowhide. This study aimed to investigate the incidence of enterotoxigenic S. aureus in ready-to-eat locally processed cowhide. Methodology: Sixty (60) RTE cowhide samples were collected from different locations in Lagos, Nigeria and analyzed using conventional microbiological and molecular techniques for the detection of toxigenic S. aureus contamination. Suspected S. aureus isolates were confirmed by the presence of thermostable endonuclease [nuc] gene in their genome. Results: Result showed that 25 (41.67%) and 20 (33.50%) samples harbored coagulase-positive S. aureus and 20 other bacterial species different from S. aureus, respectively while 15 (24.83%) of the tested ponmo samples yielded no bacterial growth. Thirteen of the 15 randomly selected from the 25 suspected isolates were confirmed as S. aureus by the presence of thermostable endonuclease [nuc] gene in their genome. Enterotoxigenic genes were confirmed in all the 13 PCR detected S. aureus. Enterotoxin B gene is most prevalent in ponmo. Multiplex PCR detection of S. aureus enterotoxins [SE] genes revealed the molecular detection of different isolates carrying staphylococcal enterotoxin types A and B, mixed strain carrying both staphylococcal enterotoxins type A and type D. Antibiotic susceptibility of 20 S. aureus isolates revealed varying degrees of susceptibility patterns against the antimicrobial agents. Generally, gentamicin 70% (14/20), azithromycin 75% (15/20), co-trimoxazole 85% (17/20), levofloxacin 95% (19/20) were the most effective antibiotics to S. aureus. A low, ?50% susceptibility was recorded to chloramphenicol 55% (11/20) and nitrofurantoin 65% (13/20). A higher resistance to streptomycin (90%; 18/20) and ceftazidime (95%; 19/20) was identified, with resistance to ceftazidime being the highest (95%; 19/20). Conclusion: It can be concluded that RTE ponmo vended in the study sites is of low hygienic quality and may be of health risk to consumers. High level hygiene practice and good manufacturing practices are required during the production, distribution and marketing of ponmo to curb the potential health consequences of eating ponmo.

The trends of isolation and antimicrobial susceptibility of group B Streptococcus in urine culture: a 7-years cross sectional study

Background: Group B Streptococcus (GBS)/Streptococcus agalactiae (S. agalactiae) is a common rectovaginal colonizer, thereby a potential agent of neonatal and maternal infection. This study estimates the trends of isolation of GBS, its antimicrobial profile in urine culture and the demographic characteristics of these patients over a 7-year period.Methods: A record-based study was conducted, which included all the urine culture reports of GBS/S. agalactiae from January 2014 to December 2020. The trend of occurrence of GBS bacteriuria, demographic characteristics and antimicrobial susceptibility pattern were analyzed.Results: Out of 137 urine samples which grew GBS/S. agalactiae, 55(40.15%) were from antenatal women. Most of the isolates were from females (72.26%), with a male preponderance noted among the elderly population (age>60 years). The predominant age group affected were adults between 20 to 59 years. The majority of the isolates (60.58%) were susceptible to all the four tested antibiotics, namely, ciprofloxacin, nitrofurantoin, ampicillin and vancomycin. Ciprofloxacin resistance was observed in 32.85% (45/137) isolates, 5.84% (8/137) isolates were resistant to ampicillin and 2.92% (4/137) were resistant to nitrofurantoin.Conclusions: All the isolates were susceptible to vancomycin. GBS/S. agalactiae is an important agent of bacteriuria in antenatal women as well as in non-pregnant population, especially the elderly males. Emerging resistance to various group of antibiotics warrants routine susceptibility testing.

Causative Microorganisms Isolated from Patients with Intra-Abdominal Infections and Their Drug Resistance Profiles: An 11-Year (2011-2021) Single-Center Retrospective Study / 生物医学与环境科学（英文）

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-spectrum β-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 IAIs 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.

Antimicrobial resistance of bacteria from pleural and peritoneal effusion:surveillance report from Hunan Provincial Antimicrobial Resistance Sys-tem,2012-2021 / 中国感染控制杂志

Objective To understand the distribution and antimicrobial resistance changes of bacteria isolated from pleural and peritoneal effusion in Hunan Province,and provide reference for correct clinical diagnosis and rational antimicrobial use.Methods Data reported by member units of Hunan Provincial Antimicrobial Resistance Survei-llance System from 2012 to 2021 were collected.Bacteria antimicrobial resistance surveillance method was imple-mented according to technical scheme of China Antimicrobial Resistance Surveillance System(CARSS),and WHO-NET 5.6 software was used to analyze the data of bacteria isolated from pleural and peritoneal effusion as well as antimicrobial susceptibility testing results.Results From 2012 to 2021,a total of 28 934 bacterial strains were iso-lated from specimens of pleural and peritoneal effusions from member units of Hunan Provincial Antimicrobial Re-sistance Surveillance System,with 5 752 strains from pleural effusion and 23 182 from peritoneal effusion.The top five bacteria isolated from pleural effusion were Escherichia coli(n=907,15.8％),Staphylococcus aureus(n=535,9.3％),Klebsiella pneumoniae(n=369,6.4％),Staphylococcus epidermidis(n=452,7.9％),and Staphy-lococcus haemolyticus(n=285,5.0％).The detection rate of methicillin-resistant Staphylococcus aureus(MR-SA)from pleural effusion was 24.3％-39.2％,and that of methicillin-resistant coagulase negative Staphylococcus(MRCNS)was 58.8％-77.1％.The top five bacteria isolated from peritoneal effusion were Escherichia coli(n=8 264,35.6％),Klebsiella pneumoniae(n=2 074,9.0％),Enterococcus faecium(n=1 458,6.3％),Staphylo-coccus epidermidis(n=1 383,6.0％),and Pseudomonas aeruginosa(n=1 152,5.0％).The detection rate of MRSA from peritoneal effusion was 22.1％-52.4％,which presented a decreasing trend(P=0.004).The detec-tion rate of MRCNS was 60.4％-79.4％.The resistance rates of Enterobacterales from peritoneal effusion to ce-fazolin,cefuroxime,ceftriaxone and cefepime all showed decreasing trends(all P＜0.05).Vancomycin-,linezo-lid-,and teicoplanin-resistant Staphylococcus strains were not found in pleural and peritoneal effusions.The resis-tance rates of Enterococcus faecium to most tested antimicrobial agents were higher than those of Enterococcus fae-calis.The resistance rates of Enterobacterales to imipenem and meropenem were ≤8.5％.The resistance rates of non-fermentative Gram-negative bacilli to imipenem and meropenem were ≤43.3％.Conclusion The data structure of Hunan Antimicrobial Resistance Surveillance System for pleural and peritoneal effusions from 2012 to 2021 is relatively complete.The constituent and antimicrobial susceptibility of isolated pathogenic bacteria vary in different years.

In vitro and in vivo antimicrobial activity of pimozide against Staphylo-coccus aureus / 中国感染控制杂志

Objective To explore the in vitro and in vivo antimicrobial activity of antipsychotic agent pimozide against Staphylococcus aureus(S.aureu).Methods The minimal inhibitory concentration(MIC)and minimum bactericidal concentration(MBC)of pimozide were determined by micro-dilution assay.Biofilm was cultured in 96-well cell culture plate,and the anti-biofilm activity of pimozide was detected by turbidimetry.The effect of pimozide on biofilm was further observed through laser confocal microscopy and SYTO9/PI staining.Combined antimicrobial effect of pimozide and other antimicrobial agents was detected by chessboard dilution method,and cytotoxicity of pimozide was detected by CCK-8 assay kit.A model of skin abscess was constructed,in vivo antimicrobial activity and toxicity of pimozide was tested.Results Pimozide showed significant dose-dependent antimicrobial activity against S.aureu,with a MIC of 8-16 μg/mL.It could significantly inhibit the formation of S.aureu biofilm and disperse the formed biofilm.The combination of pimozide and doxycycline has a synergistic antimicrobial effect in vitro,with a synergistic antimicrobial index of 0.5.It can significantly reduce the bacterial load in mouse abscess tissue in vivo,and reduce the live bacterial count from(8.25±0.13)lgarithmic value of CFU/abscess to(3.31± 0.81)logarithmic value of CFU/abscess(q=3.74,P＜0.05).The cytotoxicity of pimozide was extremely low,with a half inhibitory concentration of 64 μg/mL on cells.Conclusion Pimozide exhibits significant antimicrobial activity in vitro and in vivo with extremely low toxicity,thus is promising for the treatment of S.aureu-related local infection in psychiatric patients.

Spectrum of bacterial keratitis in North India: A retrospective analysis of six years at a tertiary care eye center

Purpose: To analyze the pattern of bacterial pathogens causing infective keratitis and their resistance to the recommended antibiotics over six years. Methods: It was a retrospective study of 9,357 cases of bacterial keratitis from January 2015 to December 2020, at a tertiary care ophthalmic center. A total of 9,547 corneal specimens were obtained from the study subjects. Demographic details of the patients, pathogenic bacteria isolated, and their antimicrobial susceptibility were noted and analyzed. Results: Bacterial pathogens were identified in 23.52% of the specimens. The most common isolates were coagulase?negative Staphylococci (60.75%), followed by Pseudomonas aeruginosa (14.23%), Staphylococcus aureus (13.92%), gram negative bacilli of the family Enterobacterales (8.64%), Streptococcus spp. (1.72%), Acinetobacter spp. (0.13%), and other non?fermenting gram?negative bacilli (0.57%). In Staphylococci, 55–80% of isolates were resistant to erythromycin, and 40–70% to fluoroquinolones, while no resistance was observed against vancomycin. 40–60% of isolates of P. aeruginosa were resistant to cephalosporins, 40–55% to fluoroquinolones, and 30–60% to aminoglycosides. Also, 40–80% of isolates of Enterobacterales were resistant to cephalosporins, and 50–60% to fluoroquinolones. Most gram?negative isolates were susceptible to carbapenems and polymyxin B. Conclusion: To the best of our knowledge, our study is the largest compilation of microbiological profile of bacterial keratitis from North India. It highlights the current trend of the bacterial pathogens that cause infectious keratitis. Staphylococci and Pseudomonas were found to be the most common pathogens. Increased resistance was seen against some of the commonly prescribed empirical antibiotics. Such evidence is useful for restructuring the empirical prescription practices from time to time.

Estudio de la Inhibición de formación de biopelículas en cepas de Pseudomonas aeruginosa en presencia de própolis / Inhibition study of biofilms production of Pseudomonas aeruginosa strains in the presence of propolis

Uno de los principales fracasos de los tratamientos antibióticos de las infecciones por P. aeruginosa, es debido a la producción de biopelículas. El objetivo de este trabajo fue estudiar la inhibición de formación de biopelículas en cepas de Pseudomonas aeruginosa en presencia de própolis. A todas las cepas se les determinó el perfil de susceptibilidad y se hicieron pruebas de sinergismo. Se detectó el nivel de producción de biopelículas sobre membranas de nitrocelulosa y por microscopía electrónica de transmisión. Se estudió la inhibición de las biopelículas por própolis por dilución en placas. En el hospital de Cumaná, "Dr. Julio Rodríguez", se aislaron cepas de P. aeruginosa, de diferentes procesos infecciosos, principalmente, pie diabético. Todas las cepas produjeron biopelículas a diferentes niveles (leve 60%, moderado 24% e intenso 16%). Sesenta por ciento de las cepas son productoras de MBL y 49% de AmpC. El antibiotipo predominante fue la resistencia a aminoglucósidos y fluoroquinolonas (XII). Siete cepas fueron resistentes a colistin. Las biopelículas tratadas con própolis (10 µg/ml), fueron inhibidas con éxito en su casi totalidad. En conclusión, el própolis logró erradicar la formación de biopelículas in vitro, rompiendo las barreras de los diferentes mecanismos de resistencia a los antibióticos expresados por las cepas de P. aeruginosa estudiadas en este trabajo

One of the main failures of antibiotics treatments of P. aeruginosa infections is due to the production of biofilms. The objective of this work was to study the inhibition of biofilm production in Pseudomonas aeruginosa strains in the presence of propolis. Susceptibility testing and synergism were performed in all strains. Biofilm production level was determined onto nitrocellulose membranes and transmission electronic microscopy. Biofilm inhibition propolis was did on plate dilution. "Dr. Julio Rodríguez" hospital, in Cumaná, P. aeruginosa strains were isolated from different infectious processes, mainly diabetic foot. All the strains produced biofilm at different levels (60% mild, 24% moderate and 16% high). Sixty percent of the strains are producers of MBL, and 49% of AmpC. The predominant antibiotype was resistance to aminoglycosides and fluoroquinolones (XII). Seven strains were resistant's to colistin. Biofilms treated with propolis (10 µg/ml) were almost completely inhibited. In conclusion, the propolis achieved to eradicate the in vitro biofilm production, breaking the barriers of the different mechanisms of resistance to the antibiotics expressed by the P. aeruginosa strains studied in this work

Quality microbiological diagnostics and antimicrobial susceptibility testing, an essential component of antimicrobial resistance surveillance and control efforts in Pacific island nations

Problem@#Emerging bacterial antimicrobial (antibiotic) resistance (AMR) is a global threat to human health. However, a majority of lower income countries do not have microbiological diagnostic testing for prompt, reliable confirmation of bloodstream infection and identification of AMR.@*Context@#Clinicians in Pacific island nations are increasingly challenged by patients who have infection due to antimicrobialresistant bacteria. Treatment of infection remains empirical because of a lack of diagnostic testing capacity and may follow guidelines that were formulated without reference to local measures of AMR prevalence. There is limited understanding among clinicians of microbiology testing and test interpretation.@*Action@#Examine the lessons learnt from pilot laboratory development programmes in two Pacific island nations that focused on establishing standard procedures for micrological diagnostics and antimicrobial susceptibility testing (AST) and on improving the training of clinicians to increase their use of laboratory services.@*Outcome@#The pilot programmes addressed a range of logistical difficulties and evaluated two blood culture systems. They also examined and improved internal QC implementation and evaluated the prevalence of AMR.@*Discussion@#Continued development of microbiological diagnostic capability in the Pacific region is paramount. Pacific Island nations need to develop the capability of at least one central laboratory to culture AMR pathogens and subject them to quality-controlled AST or arrange for suitable referral to a nearby country.

Bad bug, no test: Tigecycline susceptibility testing challenges and way forward

Tigecycline is a reserve antibiotic increasingly used for the treatment of multidrug-resistant bacteria, especially Klebsiella pneumoniae and Acinetobacter baumannii. At present, there are concerns regarding the testing and interpretation of tigecycline susceptibility to bugs such as K. pneumoniae and A. baumannii, which limit clinicians in appropriate usage. Use of appropriate method for testing such as broth microdilution is essential. In addition, tigecycline susceptibility testing is a challenge due to inconsistent results from various antimicrobial susceptibility testing automated platforms. There is a great need to define a suitable methodology along with interpretive criteria, especially for K. pneumoniae and A. baumannii. The European Committee on Antimicrobial Susceptibility Testing (EUCAST) and the Food and Drug Administration (FDA) breakpoints show wide variation and are defined for different set of organisms. Non-species-related pharmacokinetic/pharmacodynamic (PK/PD) breakpoints defined by the EUCAST can be used for organisms such as K. pneumoniae and A. Baumannii.

Performance Evaluation of the Newly Developed BD Phoenix NMIC-500 Panel Using Clinical Isolates of Gram-Negative Bacilli

BACKGROUND: The emergence of carbapenem resistance among gram-negative bacilli (GNB), mediated by carbapenemase production, has necessitated the development of a simple and accurate device for detecting minimum inhibitory concentrations (MICs) and resistance mechanisms, especially carbapenemase production. We evaluated the performance of the BD Phoenix NMIC-500 panel (BD Diagnostic Systems, Sparks, MD, USA) for antimicrobial susceptibility testing (AST) and carbapenemase-producing organism (CPO) detection. METHODS: We used 450 non-duplicate clinical GNB isolates from six general hospitals in Korea (409 Enterobacteriaceae and 41 glucose non-fermenting bacilli [GNFB] isolates). AST for meropenem, imipenem, ertapenem, ceftazidime, and ceftazidime/avibactam, and CPO detection were performed using the Phoenix NMIC-500 panel. Broth microdilution was used as the reference method for AST. The rates of categorical agreement (CA), essential agreement (EA), minor error (mE), major error (ME), and very major error (VME) were calculated in each antimicrobial. In addition, PCR and sequencing were performed to evaluate the accuracy of CPO detection by the BD Phoenix NMIC-500 panel, and the rate of correct identification was calculated. RESULTS: The CA rates were >90% for all antimicrobials tested with the Enterobacteriaceae isolates, except for imipenem (87.2%). The GNFB CA rates ranged from 92.7% to 100% for all antimicrobials. The ME rates were 1.7% for Enterobacteriaceae and 0% for GNFB. The panel identified 97.2% (243/250) of the carbapenemase-producing isolates. CONCLUSIONS: The BD Phoenix NMIC-500 panel shows promise for AST and CPO detection.

In vitro combination antimicrobial susceptibility of fosfomycin sodium / 中国感染控制杂志

Objective To evaluate in vitro antimicrobial effect of fosfomycin sodium single use and combination with other antimicrobial agents on clinically isolated Staphylococcus aureus (S.aureus), Klebsiella pneumoniae (K.pneumoniae) and Pseudomonas aeruginosa (P.aeruginosa) in China.Methods Combined antimicrobial susceptibility testing was performed with checkerboard method, minimal inhibitory concentrations (MICs) were detected by two-fold agar dilution method, susceptibility of S.aureus (n=113 strains), K.pneumoniae (n=108 strains), and P.aeruginosa (n=110 strains) isolated from 18 hospitals in China in recent three years was determined by single and combined antimicrobial susceptibility testing.Results MIC50 value of fosfomycin sodium single use were all≤32 mg/L against all tested strains, regardless of whether strains were resistant to other antimicrobial agents or not.The synergistic rate of fosfomycin sodium with levofloxacin, minocycline, oxacillin, and clindamycin against methicillin-resistant S.aureus (MRSA) was＞43％.Synergistic rate of fosfomycin sodium with levofloxacin and imipenem against imipenem-nonsusceptible P.aeruginosa was＞35％, synergistic rates of fosfomycin sodium with tested antimicrobial agents against imipenem-susceptible P.aeruginosa were all＞35％.Conclusion Fosfomycin sodium still has good antimicrobial activity against common clinical drug-resistant bacteria, such as MRSA, extended-spectrumβ-lactamase-producing K.pneumoniae and so on, it has synergistic effect with many other kinds of antimicrobial agents, suggesting that in the limited treatment of infection caused by drug-resistant bacteria, fosfomycin in combination with other antimicrobial agents may be a useful choice.

Results of bacterial resistance surveillance in a Guangdong hospital during 2015-2017 / 中国感染与化疗杂志

Objective To investigate the susceptibility profile of clinical isolates in the First Affiliated Hospital of Guangzhou Medical University during 2015-2017. Methods Susceptibility test was carried out using Kirby-Bauer method or automated systems. Results were analyzed according to CLSI 2017 breakpoints. Results A total of 17 645 clinical isolates were isolated from January 2015 to December 2017, including 3 091(17.5％)gram positive and 14 554(82.5％)gram negative bacteria. Methicillinresistant S. aureus(MRSA)and coagulase-negative Staphylococcus(MRCNS)accounted for 50.7％ and 77.9％, respectively. No staphylococcal isolates were found resistant to vancomycin, teicoplanin or linezolid. E. faecalis strains showed much lower resistance rate to most drugs tested than E. faecium. Nine(0.8％)E. faecalis isolates were found resistant to vancomycin. A total of 227 strains of the non-meningitis S. pneumoniae were tested, 44.1％ of which were isolated from adults and 55.9％ from children. Most of the S. pneumoniae isolated from adults and children were susceptible to penicillin(88.0％ and 81.1％, respectively). E. coli showed the highest proportion in three years. ESBLs were produced in 53.3％ of E. coli and 28.5％ of Klebsiella spp. A total of 255 strains of carbapenem-resistant Enterobacteriaceae(3.7％), 665 strains of carbapenem-resistant Pseudomonas aeruginosa(26.2％)and 900 strains of carbapenem-resistant Acinetobacter baumannii(57.5％)were identified. The annual change of prevalence was insignificant. A total of 141 strains of extensively-drug resistant Pseudomonas aeruginosa(5.6％)and 458 strains of extensively-drug resistant A. baumannii(29.3％)were identified, showing decreasing prevalence from 2015 to 2017. Conclusions The bacterial resistance in this hospital is relatively stable in the past three years, but it is still necessary to strengthen hospital infection control and management, and maintain good practice in surveillance of bacterial resistance.

Surveillance of bacterial resistance in Yongzhou Central Hospital of Hunan in 2016 and 2017 / 中国感染与化疗杂志

Objective To investigate the susceptibility and resistance profile of clinical isolates in Hunan Yongzhou Hospital during 2016 and 2017. Methods Antimicrobial susceptibility testing was carried out according to a unified protocol using KirbyBauer method or automated systems. Results were analyzed according to CLSI 2016 breakpoints. Results A total of 6 354 clinical isolates were collected from January 2016 to December 2017, of which 4 876(76.7％)were gram-negative bacteria, and 1 478(23.3％)were gram-positive bacteria. The top five bacterial species were Escherichia coli(33.0％), Klebsiella(17.0％), Staphylococcus aureus(9.6％), Acinetobacter(8.6％), and Pseudomonas aeruginosa(7.4％). The prevalence of methicillin-resistant Staphylococcus aureus(MRSA)was 33.8％, and prevalence of methicillin-resistant coagulase negative Staphylococcus(MRCNS)was 76.2％. The resistance rates of methicillin resistant strains(MRSA and MRCNS)to most of the tested drugs were significantly higher than those of methicillin sensitive strains(MSSA and MSCNS). No vancomycin or linezolid resistant staphylococci were identified. The resistance rate of Enterococcus faecium to most antimicrobial agents was significantly lower than that of Enterococcus faecium. No enterococcal isolate was resistant to vancomycin or linezolid. The non-meningitis S. pneumoniae strains isolated from children showed slightly higher resistance rate to penicillin(20.8％)than the strains isolated from adults(13.3％). The prevalence of extended spectrum beta-lactamases(ESBLs)in Escherichia coli and Klebsiella pneumoniae was 48.0％ and 35.7％, respectively. Most Enterobacteriaceae strains were highly sensitive to carbapenem antibiotics, showing lower resistancerate(<4％). The prevalence of carbapenem-resistant Klebsiella pneumoniae was 18.8％, and the prevalence of carbapenem-resistant E. cloacae was 14.5％. The prevalence of Acinetobacter baumannii strain resistant to imipenem and meropenem was 76.4％ and 78.6％, respectively. Conclusions Bacterial resistance is still serious. It is necessary to strengthen the monitoring of bacterial resistance, infection control, and rational use of antibiotics.

Evaluation of in vitro antimicrobial susceptibility of Bacillus anthracis strains isolated during anthrax outbreaks in Italy from 1984 to 2017

Anthrax, caused by Bacillus anthracis, is a non-contagious infectious disease that affects a wide range of animal species (primarily ruminants) including humans. Due to the often-fatal outcome in humans, quick administration of definitely effective antimicrobials is crucial either as prophylaxis or as a clinical case therapy. In this study, 110 B. anthracis strains, temporally, geographically, and genetically different, isolated during anthrax outbreaks in Italy from 1984 to 2017, were screened using a broth microdilution method to determine their susceptibility to 16 clinically relevant antimicrobial agents. The strains were isolated from various matrices (human, animal, and environmental samples) and were representative of thirty distinct genotypes previously identified by 15-loci multiple-locus variable-number of tandem repeats analysis. The antimicrobials tested were gentamicin, ceftriaxone, streptomycin, penicillin G, clindamycin, chloramphenicol, vancomycin, linezolid, cefotaxime, tetracycline, erythromycin, rifampin, amoxicillin, ciprofloxacin, doxycycline, and trimethoprim. All isolates were susceptible to most of the tested antimicrobials, with the exception of trimethoprim for which all of them showed high minimal inhibitory concentration values. An intermediate level of susceptibility was recorded for ceftriaxone and cefotaxime. Although the Centers for Disease Control and Prevention recommend the use of doxycycline, ciprofloxacin, penicillin G, and amoxicillin for treatment of human cases and for post-exposure prophylaxis to anthrax spores, this study shows a high degree of in vitro susceptibility of B. anthracis to many other antimicrobials, suggesting the possibility of an alternative choice for prophylaxis and therapy.

Antimicrobial resistance profile of clinical isolates in hospitals across China: report from the CHINET Surveillance Program, 2017 / 中国感染与化疗杂志

Objective To investigate the antimicrobial resistance profile of the clinical isolates collected from selected hospitals across China. Methods Twenty-nine general hospitals and five children's hospitals were involved in this program. Antimicrobial susceptibility testing was carried out according to a unified protocol using Kirby-Bauer method or automated systems. Results were interpreted according to CLSI 2017 breakpoints. Results A total of 190 610 clinical isolates were collected from January to December 2017, of which gram negative organisms accounted for 70.8％ (134 951/190 610) and gram positive cocci 29.2％ (55 649/190 610). The prevalence of methicillin-resistant strains was 35.3％ in S. aureus (MRSA) and 80.3％ in coagulase negative Staphylococcus (MRCNS) on average. MR strains showed much higher resistance rates to most of the other antimicrobial agents than MS strains. However, 91.6％ of MRSA strains were still susceptible to trimethoprim-sulfamethoxazole, while 86.2％ of MRCNS strains were susceptible to rifampin. No staphylococcal strains were found resistant to vancomycin. E. faecalis strains showed much lower resistance rates to most of the drugs tested (except chloramphenicol) than E. faecium. Vancomycin-resistant Enterococcus (VRE) was identified in both E. faecalis and E. faecium. The identified VRE strains were mainly vanA, vanB or vanM type based on phenotype or genotype. The proportion of PSSP or PRSP strains in the non-meningitis S.pneumoniae strains isolated from children decreased but the proportion of PISP strains increased when compared to the data of 2016. Enterobacteriaceae strains were still highly susceptible to carbapenems. Overall, less than 10％ of these strains (excluding Klebsiella spp.) were resistant to carbapenems. The prevalence of imipenem-resistant K. pneumoniae increased from 3.0％ in 2005 to 20.9％ in 2017, and meropenem-resistant K. pneumoniae increased from 2.9％ in 2005 to 24.0％ in 2017, more than 8-fold increase. About 66.7％ and 69.3％ of Acinetobacter (A. baumannii accounts for 91.5％) strains were resistant to imipenem and meropenem, respectively. Compared with the data of year 2016, P. aeruginosa strains showed decreasing resistance rate to carbapenems. Conclusions Bacterial resistance is still on the rise. It is necessary to strengthen hospital infection control and stewardship of antimicrobial agents. The communication between laboratorians and clinicians should be further improved in addition to surveillance of bacterial resistance.

Surveillance of antimicrobial resistance in Peking Union Medical College Hospital in 2017 / 中国感染与化疗杂志

Objective To investigate the antimicrobial resistance of clinical bacterial isolates in Peking Union Medical College Hospital (PUMCH) in 2017. Methods A total of 9 515 non-duplicate clinical isolates were collected from January 1 to December 31, 2017. Disc diffusion test (Kirby-Bauer method) and E-test method were employed to determine antimicrobial susceptibility. Results Gram-negative bacilli and gram-positive cocci accounted for 68.2％ and 31.8％, respectively among the 9 515 clinical isolates. Methicillin-resistant strains in S. aureus (MRSA) and coagulase-negative Staphylococcus (MRCNS) accounted for 25.6％ and 73.3％, respectively. Extended-spectrum β-lactamases (ESBLs) -producing strains accounted for 47.6％ (877/1 842), 27.6％ (335/1 213) and 33.0％ (59/179) in E. coli, Klebsiella spp (K. pneumoniae and K. oxytoca) and P. mirabilis, respectively. Enterbacteriaceae strains were still highly susceptible to carbapenems, with an overall resistance rate of ≤ 3.8％. The resistance rates of K. pneumoniae to imipenem and meropenem were 8.5％ and 8.2％, respectively. About 72.7％ and 70.4％ of A. baumannii isolateswere resistant to imipenem and meropenem. The resistance rate of P. aeruginosa to imipenem and meropenem was 14.8％ and 10.0％, respectively. The prevalence of extensively drug-resistant strains in A. baumannii, P. aeruginosa and K. pneumoniae was 31.7％ (239/753), 1.0％ (10/1 035), and 3.0％ (33/1 117), respectively. Conclusions The common bacterialisolates show various level of resistance to antimicrobial agents. Laboratory staff should improve communication with clinicians to prevent the spread of resistant strains.

Surveillance of antibiotic resistance in clinical isolates from the First Affiliated Hospital of Anhui Medical University during 2017 / 中国感染与化疗杂志

Objective To investigate the antibiotic resistance of clinical isolates in the First Affiliated Hospital of Anhui Medical University during 2017. Methods Antimicrobial susceptibility testing was carried out according to a unified protocol using automated system or Kirby-Bauer method. Results were interpreted according to the breakpoints of CLSI 2017. The data were analyzed by WHONET 5.6 software. Results A total of 6 495 non-duplicate clinical isolates were collected in 2017. There were 1 727 strains (26.6％) of gram-positive bacteria and 4 768 strains (73.4％) of gram-negative bacteria. The most frequently isolated microorganisms were E. coli (19.8％), followed by Klebsiella pneumoniae and Acinetobacter baumannii. The strains were mainly isolated from respiratory tract (37.0％) and urine (23.1％). The prevalence of MRSA and MRCNS in Staphylococcus aureus and coagulase-negative Staphylococcus was 50.1％ and 82.1％, respectively. No Staphylococcus strains were found resistant to vancomycin or linezolid. E. faecalis and E. faecium accounted for 49.9％ and 40.4％ of total Enterococcus isolates. The prevalence of ESBLs-producing strains was 57.6％ in E. coli, 27.1％ in Klebsiella spp. and 33.0％ in Proteus mirabilis. Enterobacteriaceae strains were still highly susceptible to carbapenems antibiotics. The Klebsiella pneumoniae isolates in 2017 showed significantly higher resistance rate to imipenem and meropenem than the strains in 2016. However, Pseudomonas aeruginosa and Acinetobacterbaumannii strains showed lower resistance rates to carbapenems than the strains in 2016. Conclusions The bacterial isolates in 2017 pose serious threat to clinical antibiotic therapy. More attention should be paid to rational use of antimicrobial agents and infection control measures.

Surveillance of antimicrobial resistance in Dongguan Tungwah Hospital during 2016 / 中国感染与化疗杂志

Objective To investigate the antimicrobial resistance profile of clinical isolates in Dongguan Tungwah Hospital during 2016.Methods Antimicrobial susceptibility testing was carded out for the clinical isolates collected from Dongguan Tungwah Hospital according to a unified protocol using Kirby-Bauer method or automated systems.Result were analyzed according to CLSI 2016 breakpoints.Results Of the 3 482 clinical isolates,gram positive cocci and gram negative bacilli accounted for 34.4％ (1 199/3 482) and 65.6％ (2 283/3 482),respectively.The prevalence of methicillin-resistant strains was in 28.7％ (86/300) in S.aureus and 77.7％ (300/386) in coagulase-negative Staphylococcus isolates.No staphylococcal strains were found resistant to vancomycin or linezolid.Overall,one E.faecium strain was identified as resistant to vancomycin by instrument method and confirmed by vancomycin E test.The prevalence of ESBLs-producing strains was 59.6％ (337/565) in E.coli and 29.8％ (115/386) in Klebsiella spp.(K.pneumoniae and K.oxytoca).Enterobacteriaceae strains were still highly susceptible to carbapenems.Overall,0.4％ and 0.2％ of the Enterobacteriaceae strains were resistant to imipenem and meropenem,respectively.About 38.3％ and 36.9％ of Acinetobacter strains were resistant to imipenem and meropenem,respectively.Conclusions Surveillance of antimicrobial resistance is most important and valuable for understanding the changing resistant pattern in local hospital and rational selection of antimicrobial agents.More attention should be paid to surveillance of antimicrobial resistance to avoid the spread of drug resistant strains.