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.

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.

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.

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.

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.

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.

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.

Introduction of Clinical and Laboratory Standards Institute Antibiotic Susceptibility Testing Subcommittee Meeting / 대한임상미생물학회지

Laboratory medicine is a specialized division that supports physicians in the care of patients by providing rapid and accurate in vitro diagnostic tests. Standardization of every component of a specific test is essential for producing accurate results. The Clinical and Laboratory Standards Institute (CLSI) was founded to develop a formal consensus process for standardization in 1968, and has been publishing standards and guidelines covering all aspects of clinical, research, and other laboratory work. CLSI guidelines are widely used around the world for standardization. The CLSI antimicrobial susceptibility testing subcommittee (AST SC) consists of 6 standing and many ad hoc working groups. Members of the AST SC review submitted proposals and suggestions, decide on approving these submissions in face-to-face meetings held twice a year, and revise CLSI documents accordingly. As these face-to-face meetings are open to anyone who registers to attend, I strongly encourage the members of our Society to attend and actively participate in document development.

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 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.

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.

Same-Day Identification and Antimicrobial Susceptibility Testing of Bacteria in Positive Blood Culture Broths Using Short-Term Incubation on Solid Medium with the MicroFlex LT, Vitek-MS, and Vitek2 Systems

BACKGROUND: Early and appropriate antibiotic treatment improves the clinical outcome of patients with septicemia; therefore, reducing the turn-around time for identification (ID) and antimicrobial susceptibility test (AST) results is essential. We established a method for rapid ID and AST using short-term incubation of positive blood culture broth samples on solid media, and evaluated its performance relative to that of the conventional method using two rapid ID systems and a rapid AST method. METHODS: A total of 254 mono-microbial samples were included. Positive blood culture samples were incubated on blood agar plates for six hours and identified by the MicroFlex LT (Bruker Daltonics) and Vitek-MS (bioMeriéux) systems, followed by AST using the Vitek2 System (bioMeriéux). RESULTS: The correct species-level ID rates were 82.3% (209/254) and 78.3% (199/254) for the MicroFlex LT and Vitek-MS platforms, respectively. For the 1,174 microorganism/antimicrobial agent combinations tested, the rapid AST method showed total concordance of 97.8% (1,148/1,174) with the conventional method, with a very major error rate of 0.5%, major error rate of 0.7%, and minor error rate of 1.0%. CONCLUSIONS: Routine implementation of this short-term incubation method could provide ID results on the day of blood culture-positivity detection and one day earlier than the conventional AST method. This simple method will be very useful for rapid ID and AST of bacteria from positive blood culture bottles in routine clinical practice.

Antimicrobial resistance profile and fluoroquinolone resistance genes in Nocardia / 中国感染与化疗杂志

Objective To investigate the species, antimicrobial resistance, and fluoroquinolone resistance gene profiles of Nocardia in the General Hospital of Ningxia Medical University. Methods Nocardia isolates were collected in the General Hospital of Ningxia Medical University during the period from January 2013 to June 2017. Broth dilution method was used to determine the susceptibility of the Nocardia strains to 15 antibiotics. Fluoroquinolone resistance genes gyrA, parC, qnrA, qnrB and qnrS were detected by polymerase chain reaction. Results A total of 16 isolates of Nocardia were collected, including Nocardia cyriacigeorgica (62.6％, 10/16), Nocardia farcinica (18.7％, 3/16), and Nocardia otitidiscaviarum (18.7％, 3/16). Most Nocardia isolates (81.2％, 13/16) were resistant to ciprofloxacin. About 12.5％, 12.5％, 25.0％ and 18.7％ of the strains were resistant to ceftriaxone, tobramycin, gentamicin and cefepime. Overall, gyrA, parC, qnrA and qnrB were identified in 18.8％, 37.5％, 25.0％ and 18.7％ of the Nocardia strains. The qnrS gene was not found in any strain. Conclusions The most frequently Nocardia species in the hospital was Nocardia cyriacigeorgica. Fluoroquinolone resistance is serious in the Nocardia isolates.Fluoroquinolone resistance of Nocardia is likely associated with gyrA, parC, qnrA, and qnrB genes. We should pay close attention to the emergence and antimicrobial susceptibility of Nocardia infection.

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.

Verification Process of American CLSI M52-Commercial Microbial Identification System and Antimicrobial Susceptibility Testing System / 现代检验医学杂志

Before performing patient testing with commercial microbial test systems,each laboratory must verify that it can obtain performance specifications comparable to those of the manufacturer.This includes trueness,precision (reproducibility),and reportable range of test results,and verifying that the manufacturer's reference ranges are appropriate for the laboratory's patient population.American Clinical and Laboratory Standards Institute has set up a committeeto develop a verification process and a quality assurance program for commercial microbial identification system and antimicrobial susceptibility testing system,in order to provide recommendations for US Food and Drug Administration (FDA).This guidance is applicable to instrument systems widely used in clinical laboratories and can also be used for manual testing of microbiological identification and antimicrobial susceptibility testing.The aim of this article is to provide advice for the microbial identification system and antimicrobial susceptibility testing system verification process,based on principles of microbiological identification and antimicrobial susceptibility and CLSI M52 guideline.

Pathogens resulting in acute exacerbation of chronic obstructive pulmonary disease in patients in Ordos area / 中国感染控制杂志

Objective To understand the distribution and antimicrobial resistance of pathogens isolated from patients with acute exacerbation of chronic obstructive pulmonary disease(AECOPD)in Ordos area,so as to provide guidance for rational antimicrobial use.Methods Sputum culture and antimicrobial susceptibility testing results of 372 patients with AECOPD in Ordos area in 2013-2015 were analyzed,and the quality of life before acute exacerbation was assessed.Results A total of 296 strains of pathogens were isolated from 372 patients,252(85.14%)of which were gram-negative bacteria,the major were Pseudomonas aeruginosa(n=58,19.59%),Klebsiella pneumoniae(n=51,17.23%),Acinetobacter baumannii(n=50,16.89%),Stenotrophomonas maltophilia(n=22,7.43%),Escherichia coli(n=19,6.42%),and Enterobacter cloacae(n=16,5.41%);27(9.12%)were fungi,the major was Candida albicans(n=19,6.42%);17(5.74%)were gram-positive bacteria,the predominant species was Staphylococcus aureus.Patients with CAT(COPD assement test)score≥10 had higher proportion of isolating Pseudomonas aeruginosa and Acinetobacter baumannii than those with CAT score<10.Conclusion The main pathogens from patients with AECOPD are gram-negative strains,CAT score prior to exacerbation may be related to the emergence of pathogens at AECOPD.

Pathogen distribution and susceptibility profile of fungal isolates from bloodstream infections during the period from 2013 through 2015 / 中国感染与化疗杂志

Objective To investigate the pathogen distribution and susceptibility profile of fungal isolates from bloodstream infections,and valuate the clinical utility of G test in diagnosis of fungal infections for the purpose to improve antifungal therapy.Methods A retrospective analysis was carried out to analyze the fungal pathogens isolated from bloodstream infections in the First Affiliated Hospital of Nanjing Medical University during the period from January 2013 through December 2015 and their antimicrobial susceptibility.Results A total of 114 fungal strains were isolated from bloodstream infections during the 3-year period,most of which were Candida (99/114,86.8％),especially Candida albicans (30.7％).About 41.2％ (47/114) of the fungal strains were isolated from Department of Thoracic Surgery (10,5 and 4 strains in 2013,2014 and 2015),Hematology (11 strains in 2014),and ICU (7 strains in 2014).Antimicrobial susceptibility testing showed that all the fungal strains (100％) were susceptible to amphotericin B,but 83.5％ susceptible to itraconazole (the lowest).G test was positive before the result of blood culture in 13 of the 54 patients who received G test.Conclusions Candida was the most common fungus in fungal bloodstream infection.Amphotericin B is the most active antifungal agent in vitro.Blood culture combined with serological test can provide clinicians an earlier and reliable diagnosis.