Clinical evaluation of direct drug sensitivity test for blood culture positive broths / 中华检验医学杂志

Objective:To evaluate the clinical performance of direct antimicrobial susceptibility test in blood culture-positive broth, and to provide a basis for optimizing the antibiotic use strategy in clinical bloodstream infection.Methods:A retrospective analysis was conducted on 780 blood culture-positive samples collected in Peking University People′s Hospital from May 2017 to December 2021. The direct antimicrobial susceptibility test was performed by disk diffusion method on blood culture-positive broth. The antimicrobial susceptibility breakpoints were in accordance with Clinical and Laboratory Standards Institute (CLSI) M100 S32 edition document.Results:In this study, a total of 331 strains of Gram-negative bacteria (139 strains of Escherichia coli, 79 strains of Klebsiella pneumoniae, 35 strains of Pseudomonas aeruginosa, 21 strains of Acinetobacter baumannii) and 396 strains of Gram-positive cocci (25 strains of Staphylococcus aureus, 316 strains of coagulase-negative staphylococci, 47 strains of Enterococcussp.) were collected, after excluding 53 cases with two or more isolates. Compared with the routine antimicrobial susceptibility test (AST), the rates of category agreement (CA), major error (ME), and very major error (VME) of Gram-negative bacteria were 86.0% (1368/1 591), 8.7% (139/1 591), and 0.5% (8/1 591), respectively. On the other hand, the CA%, ME%, and VME% of Gram-positive cocci were 89.2% (960/1 076), 7.5% (81/1 076), and 1% (11/1 076), respectively. Regarding the individual antimicrobial agents, the CA% of Escherichia coli was 16/17 for imipenem, 90.1% (109/121) for meropenem, and 70.8% (85/120) for cefepime. For Klebsiella pneumoniae, the CA% of was 10/13 for imipenem, 80.9% (55/68) for meropenem, and 80.3% (53/66) for cefepime. The CA% of meropenem in Pseudomonas aeruginosa and Acinetobacter baumannii were 96.0% (24/25) and 16/16. The CA% of linezolid and cefoxitin in Staphylococcus aureus were 100% (25/25) and 100% (24/24), respectively. The CA% of linezolid, cefoxitin and gentamicin in coagulase-negative staphylococci were 98.9% (269/272), 94.5% (277/293) and 71.6% (194/271) respectively. Finally, for Enterococcus sp., the CA% of vancomycin and ampicillin were 91.5% (43/47) and 94.7% (36/38), respectively. Conclusion:Compared with the conventional AST, the blood culture-positive broth direct AST exhibited high category agreement and low error rates for both Gram-negative bacteria and Gram-positive cocci, which can serve a rapid alternative for AST in cases of clinical bloodstream infection.

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.

Comparación de los perfiles de resistencia antimicrobiana de Escherichia coli uropatógena e incidencia de la producción de betalactamasas de espectro extendido en tres establecimientos privados de salud de Perú / Comparison of Escherichia coli antibiotic-resistance profiles and incidence of beta- lactamase phenotypes in three private health facilities in Perú

Introducción. La aparición de enterobacterias multirresistentes y productoras de betalactamasas de espectro extendido en pacientes ambulatorios con infecciones urinarias representa un problema de salud pública en Perú. Objetivo. Comparar los perfiles de resistencia de Escherichia coli uropatógenas e identificar los fenotipos de cepas productoras de betalactamasas de espectro extendido en tres establecimientos privados de salud localizados en las regiones de la costa, la sierra y la selva de Perú. Materiales y métodos. Se llevó a cabo durante el 2016 un estudio descriptivo de 98 muestras de orina de pacientes con infección urinaria, 35 procedentes de Lima (costa), 38 de Juliaca (sierra) y 25 de Iquitos (selva), en el que se determinó la sensibilidad antimicrobiana utilizando ocho discos antibióticos. Asimismo, se evaluó la producción de betalactamasas de espectro extendido con discos de cefotaxima, de ceftazidima o de su combinación, con ácido clavulánico en agar Mueller-Hinton. Resultados. Se identificaron 18 perfiles de resistencia que incluían desde los sensibles a todos los antibióticos hasta los resistentes simultáneamente a siete antibióticos, con el 18,4 % de aislamientos resistentes a un antibiótico y el 54,0 % de multirresistentes. Se detectó producción de betalactamasas en el 28,6 % de las cepas procedentes de la región de Puno. También, se observó un mayor número de casos en el rango de edad de 31 a 45 años con resistencia a ceftazidima, ceftriaxona, gentamicina y trimetoprim-sulfametoxazol en el establecimiento de salud de Puno. Conclusión. Los perfiles de resistencia variaron según la localización geográfica del establecimiento de salud, observándose mayor resistencia a los antibióticos en la región de la sierra de Perú, con el 28,6 % de cepas productoras de betalactamasas de espectro extendido.

Introduction: The appearance of multidrug-resistant and beta-lactamase producing enterobacteria in outpatient care facilities represent a public health problem in Perú. Objective: To compare the resistance profiles of uropathogenic Escherichia coli and to identify extended-spectrum beta-lactamase-producing phenotypes in three private health facilities located in the Peruvian coast, Andean and jungle regions. Materials and methods: We conducted a descriptive study on 98 urine samples from Lima (coast), Juliaca (Andean region) and Iquitos (jungle region) during 2016. We determined the antimicrobial susceptibility in 35 samples from Lima, 38 from Juliaca and 25 from Iquitos using eight antibiotic disks in samples from patients diagnosed with urinary infection. We also evaluated the production of extended-spectrum beta-lactamases with cefotaxime and ceftazidime disks and a combination of both with clavulanic acid on Mueller-Hinton agar. Results: We identified 18 resistance profiles ranging from those sensitive to others simultaneously resistant to seven antibiotics: 18.4% resistant to one and 54.0% to multiple antibiotics. We detected beta-lactamase production in 28.6% of the strains from the Puno region. Likewise, we observed a greater number of cases with resistance to ceftazidime, ceftriaxone, gentamicin, and trimethoprim-sulfamethoxazole in Puno's health facility in patients within the 31 to 45 year age range. Conclusion: Resistance profiles varied according to the geographical location of the health facilities under study. Resistance to antibiotics was higher in the Andean region with 28.6% of strains producing extended-spectrum beta-lactamases.

In silico and in vitro assay of Hexagamavunon-6 analogs, Dibenzilyden-N-Methyl-4-piperidone as antibacterial agents

A new series of analogs Hexagamavunon-6 (HGV-6) was prepared and screened for antibacterial activity againstStreptococcus mutans (ATCC 25175), Escherichia coli (ATCC 25922), Bacillus subtilis (ATCC 6633), Psedomonasaeruginosa (ATCC 27853), Klebsiella pneumoniae, and Enterococcus faecalis (ATCC 29212) using disk diffusionmethod. The antibacterial results showed that 3,5-Bis-(2',4'-dichlorobenzilyden)-N-methyl-4-piperidone (1c)compound display significant inhibition and broad-spectrum antibacterial activity. This is in accordance with the insilico evaluation showing that compound 1c has a lower docking score than both compounds 1a and 1b. None of thetested compounds were as active as the reference standard drug Amoxicillin.

Antimicrobial activity of oregan and clove essential oils against some foodborne pathogens / Atividade antimicrobiona dos óleos essenciais de orégano e cravo frente a patógenos alimentares

The tendency to replace synthetic antimicrobials for natural ones in food industry and an increase in bacterial resistance to antibiotics resulted in a necessity to find new alternatives, and essential oils are emerging as promising substitutes for synthetic chemicals in food preservation. The objective of this work was to test the antimicrobial activity of oregano (OEO) and clove (CEO) essential oils over a range of bacteria, molds and yeast of importance as pathogens or food spoilage. The antimicrobial activity of oregano and clove essential oils were analyzed by disk diffusion method and broth microdilution test (MIC) of OEO and CEO were determined for each tested microorganism. OEO and CEO were evaluated in natura (IN) and after thermal processing (TP) at 120 o C for 5 min. Both OEO and CEO presented the same inhibition zones for IN and TP samples, for all tested microorganisms, indicating that these oils can be thermally processed maintaining their antimicrobial activity. For OEO and CEO, the more sensitive microorganisms were the fungi (Aspergillus niger, Penicillium citrinum and Candida albicans), followed by Staphylococcus aureus, Bacillus cereus and Methicillin - resistant Staphylococcus aureus (MRSA); the lowest antimicrobial activities were observed against Streptococcus mutans and Enterococcus faecalis. In general, OEO resulted in higher inhibition zones and lower MIC values for all tested microorganisms, suggesting that it was more effective as an antimicrobial agent than CEO (AU)

A preferência mundial para alimentos mais saudáveis e livres de aditivos químicos pelos consumidores, associada ao aumento da resistência bacteriana, resultaram na necessidade de medidas alternativas no setor de alimentos. Os óleos correspondem a antimicrobianos naturais e constituem uma classe emergente como substitutos dos produtos químicos sintéticos na conservação de alimentos. O objetivo deste trabalho foi avaliar a atividade antimicrobiana de óleos essenciais de orégano (OEO) e cravo (CEO ) frente a bactérias, fungos e leveduras de importância no setor de alimentos. OEO e CEO foram avaliados in natura (IN) e após processamento térmico (TP) a 120 o C por 5 minutos. Para avaliar a atividade antimicrobiana frente a cada microrganismo empregou-se o método de discodifusão e o teste de microdiluição em caldo (MIC). Tanto o OEO quanto o CEO apresentaram zonas de inibição semelhantes para amostras IN e TP, indicando que a atividade antimicrobiana desses óleos são resistentes a altas temperaturas. Os microrganismos mais sensíveis para ambos os óleos essenciais foram os fungos (Aspergillus niger, Penicillium citrinum e Candida albicans), seguidos por Staphylococcus aureus, Bacillus cereus e Staphylococcus aureus resistente à meticilina (MRSA). Já as cepas Streptococcus mutans e Enterococcus faecalis apresentaram uma maior resistência frente à atividade antimicrobiana dos óleos essenciais. Em geral, os maiores halos de inibição e menores valores de MIC foram obtidos quando empregado o OEO, sugerindo uma maior atividade microbiana do mesmo quando comparado ao CEO. (AU)

Determination of Colistin Resistance by Simple Disk Diffusion Test Using Modified Mueller-Hinton Agar

BACKGROUND: Colistin has become a last-resort antibiotic for the management of multidrug-resistant gram-negative bacteria. The disk diffusion test is cheap and easy to perform but may be unreliable for colistin susceptibility testing due to poor diffusion of the large colistin molecule. An improved agar diffusion test would increase the reliability of colistin susceptibility testing. This study aimed to modify Muller-Hinton agar (MHA) to improve colistin diffusion in agar.METHODS: MHA was modified by reducing the agar concentration from 100% to 30% and supplementing with protamine. We tested 60 gram-negative clinical isolates of Pseudomonas aeruginosa (N=27) and Acinetobacter calcoaceticus-baumannii complex (N=33). Disk diffusion test results were interpreted based on minimum inhibitory concentrations determined by broth microdilution.RESULTS: The modified MHA yielded the best performance metrics, including 94.7% sensitivity, 100% specificity, and an area under the curve of 0.995 (95% confidence interval, 0.982–1.000), P<0.001, at a cut-off point of 13 mm.CONCLUSIONS: A reduction of the agar concentration from 100% to 30% and the addition of protamine improved colistin diffusion in agar and allowed routine colistin susceptibility testing in a clinical microbiology laboratory, but should be handled with caution.

Isolation, identification and antibiogram profiling of bacteria isolated from water, seafood, and macroplastic samples from Baseco Beach, Manila Bay

Background and Objective@#Manila Bay plays an important role both in economics and ecology because it serves as the major economic center of the Philippines and as it harbors different habitats and biodiversity. Unfortunately, it is threatened by various pollutions including the unregulated discharge of wastewater from industrial, agricultural, and household sectors and improper disposal of trash such as macroplastics among others. All these contributes to the current state of Manila Bay. This study identified bacteria isolated from water, seafood and floating macroplastic samples from Baseco Beach, Manila Bay and determined their antibiogram profiles. @*Methodology@#Bacterial isolates were obtained from water, seafoods and macroplastic samples from Baseco Beach, Manila Bay using conventional culture techniques. Identification of the isolates was done using Vitek-2 Automated System and antibiogram profiling was done using Kirby-Bauer Disk Diffusion Susceptibility Test. @*Results and Conclusions@#A total of 30 bacterial isolates were obtained from different samples from water, seafood and macroplastic samples from Baseco Beach, Manila Bay. These isolates were identified and found to belong to 13 different bacterial species with Bacillus spp. comprising 33.33% of the isolates (10 out of 30), and Vibrio alginolyticus comprising 23.33% of the isolates (7 out of 30) and the other species comprise the remaining 43.34% (Pseudomonas spp., Vibrio fluvialis, Klebsiella pneumoniae, Shewanella alga, Sphingomonas paucimobilis, Staphylococcus haemolyticus, Chryseobacterium indologenes, Myroides sp. and Aeromonas salmonicida). Of these, six out of 30 isolates (20%) showed susceptibility to all six representative antibiotics used (Cefazolin 30μg, Gentamicin 10 μg, Chloramphenicol 30 μg, ampicillin 10 μg, Cefuroxime 30 μg, Ceftazidime 30 μg) while 7 isolates (23.33%) were resistant to only one class of antibiotic. Moreover, 17 out of 30 isolates (56.66%) were resistant to two or more classes of antibiotic while only one isolate (3.33%) was found to be resistant to gentamicin. All 30 isolates (100%) were susceptible to chloramphenicol. Interestingly, three antibiotic resistant (AMR) bacteria were isolated from macroplastics namely Pseudomonas oleovorans (S2), Vibrio alginolyticus (S5), and Pseudomonas alcaligenes (S29) which were all resistant to ampicillin and cefazolin. This is the first study in the Philippines to isolate AMR bacteria from macroplastics from Manila Bay. The presence of AMR bacteria in macroplastics shows that these materials can be a reservoir for its dynamics and distribution. Lastly, with the emergence of antimicrobial resistant bacteria, the elucidation of the antibiogram profile of bacteria is necessary to determine its implication sand threats to public health. This study served as a baseline study of presence of AMR bacteria in macroplastic samples from Manila Bay.

Antimicrobial susceptibility and minimal inhibitory concentration of bacteria isolated from the eyes of dogs with keratoconjunctivitis sicca / Susceptibilidade antimicrobiana e concentração inibitória mínima de bactérias isoladas dos olhos de cães com ceratoconjuntivite seca

The objective of this study was to evaluate the antimicrobial susceptibility profile of bacteria isolated from the eyes of dogs with keratoconjunctivitis sicca (KCS). We evaluated 65 dogs diagnosed with KCS and 30 healthy dogs (Control Group). Conjunctival swab samples were collected after KCS was diagnosed. Microbiological examinations were performed, including aerobic culture, antimicrobial susceptibility testing and minimum inhibitory concentration (MIC) determination for chloramphenicol, tobramycin, ofloxacin and moxifloxacin. MICs of the fifteen most resistant strains of Staphylococcus pseudintermedius (Staphylococcus intermedius Group, SIG) and the fifteen most resistant strains of gram-negative bacteria were determined. By percentage, the microorganisms exhibited the highest susceptibility to polymyxin B, tobramycin and chloramphenicol and the lowest to tetracycline. Three multi-drug-resistant strains of SIG were detected: one displayed isolated susceptibility to cefazolin, another to vancomycin, and another to polymyxin B and amikacin. The species of bacteria isolated from the eyes of dogs with KCS presented variable susceptibility to the antibiotics tested. We found evidence of the emergence of quinolone-resistant strains of SIG and further evidence of increased ocular prevalence. These findings reinforce the need to identify the bacteria involved and their antimicrobial susceptibility profile, as secondary infections can serve as exacerbating and perpetuating factors in KCS.(AU)

O objetivo deste estudo foi avaliar o perfil de susceptibilidade antimicrobiana de bactérias isoladas de olhos de cães com ceratoconjuntivite seca (CCS). Foram avaliados 65 cães com diagnóstico de CCS e 30 cães saudáveis ​​(Grupo Controle). Depois do diagnosticado de CCS, suabes conjuntivais foram coletados. Exames microbiológicos foram realizados, incluindo cultura aeróbia, teste de susceptibilidade antimicrobiana e determinação da concentração inibitória mínima (CIM) para cloranfenicol, tobramicina, ofloxacina e moxifloxacina. Para determinar a CIM, foram selecionadas as quinze cepas mais resistentes de Staphylococcus pseudintermedius (Staphylococcus intermedius Group-SIG) e as quinze cepas mais resistentes de bactérias gram-negativas. Os microrganismos apresentaram maior suscetibilidade percentual à polimixina B, tobramicina e cloranfenicol e menor suscetibilidade à tetraciclina. Três cepas de SIG resistentes a múltiplos medicamentos foram detectadas, do quais um demonstrou suscetibilidade isolada à cefazolina, outro à vancomicina e outro à polimixina B e à amicacina. As espécies de bactérias isoladas dos olhos de cães com CCS apresentaram suscetibilidade variável aos antibióticos testados. Encontramos evidências do surgimento de cepas resistentes à quinolona de S. pseudintermedius e outras evidências de aumento da prevalência ocular. Esses achados reforçam a necessidade de identificar as bactérias envolvidas e seu perfil de susceptibilidade aos antimicrobianos, pois as infecções secundárias podem servir como fatores exacerbantes e perpetuantes na CCS.(AU)

Resistencia inducible a clindamicina en Staphylococcus aureus resistentes a meticilina aislados de pacientes pediátricos en Paraguay / Inducible resistance to clindamycin in methicillin-resistant Staphylococcus aureus isolated from Paraguayan children

Resumen Introducción: El método de difusión de doble disco se presenta como una alternativa diagnóstica que permite identificar aislados de Staphylococcus aureus susceptibles a clindamicina, ante el aumento de resistencia a meticilina, reduciendo así la posibilidad de fallo en el tratamiento. Objetivo: Determinar la frecuencia de resistencia a clindamicina inducida por eritromicina en S. aureus resistentes a meticilina (SARM) aislados de niños paraguayos. Materiales y Métodos: Estudio observacional, descriptivo, de corte transversal. Se colectaron 145 aislados S. aureus que causaron infecciones de piel y tejidos blandos y osteo-articulares en pacientes pediátricos del Hospital Central del Instituto de Previsión Social en el período de diciembre-2012 a noviembre-2013. La resistencia a clindamicina se determinó por métodos automatizados y de difusión de doble disco. Se realizó reacción de polimerasa en cadena para genes ermA, ermB, ermC y msrA de aislados representativos. Resultados: La resistencia global a meticilina y clindamicina fue de 67 y 13%, respectivamente (11% atribuible al mecanismo de resistencia a clindamicina inducible). Los genes ermC y msrA fueron detectados individualmente en 25 y 17% de los aislados, respectivamente, mientras que un aislado presentó ambos genes en simultáneo. Discusión: La frecuencia de mecanismo de resistencia inducible a clindamicina señala la importancia de los métodos de difusión de doble disco en la práctica microbiológica, así como se encuentran en los límites de puntos de cortes considerados como aceptables para el uso de este antimicrobiano para infecciones cutáneas y osteo-articulares causadas por SARM.

Background: The double disc diffusion method is an alternative diagnostic that allows the identification of Staphylococcus aureus isolates apparently susceptible to clindamycin but that may develop resistance due to an induction phenomena, mainly asociated to the increase in resistance to methicillin, thus increasing the possibility of failure in the treatment. Aim: To determine the frequency of induced clindamycin resistance in methicillin-resistant S. aureus (MRSA) isolated from Paraguayan children. Materials and Methods: In this cross sectional study, we collected 145 S. aureus isolates that caused skin and soft tissue and osteoarticular infections in pediatric patients of the Central Hospital I.P.S. in the period from December-2012 to November-2013. Resistance to clindamycin was determined by automated methods and double disc diffusion. PCR was performed for ermA, ermB, ermC and msrA genes from representative isolates. Results: The global resistance to methicillin and clindamycin was 67 and 13%, respectively (11% attributable to the inducible mechanism). The ermC and msrA genes were detected individually in 25 and 17% of the isolates respectively while an isolate presented both genes simultaneously. Discussion: The frequency of inducible resistance to clindamycin indicates the importance of double disc diffusion methods in microbiological practice, as well as being within the cut off points considered acceptable for the use of this antibiotic for skin infections. and osteoarticular caused by MRSA.

Sensibilidad a los antimicrobianos de aislamientos de Streptococcus equi subsp. equi de la provincia de Buenos Aires, Argentina / Antimicrobial susceptibility in isolates of Streptococcus equi subsp. equi from Buenos Aires province, Argentina

Streptococcus equi subsp. equi es el agente etiológico de la adenitis equina, una enfermedad infecciosa que afecta al tracto respiratorio superior y linfonódulos de cabeza y cuello de equinos. La terapia antimicrobiana tradicional incluye como antibiótico de primera elección a la penicilina G (PEN), a la que los estreptococos suelen ser sensibles. El objetivo de este trabajo fue estudiar el perfil de sensibilidad a distintos antimicrobianos de cepas de S. equi que circulan en la provincia de Buenos Aires, Argentina. Se estudiaron 92 aislamientos mediante el método de difusión con discos; los antimicrobianos evaluados fueron PEN, cefotaxima, eritromicina, tetraciclina, enrofloxacina (ENR), trimetroprima-sulfametoxazol (TMS), ciprofloxacina, clindamicina (CLI), estreptomicina (STR) y florfenicol. Se determinó la concentración inhibitoria mínima (CIM) de la PEN y de aquellos antimicrobianos frente a los cuales S. equi mostró resistencia o sensibilidad intermedia. Se obtuvieron altos porcentajes de sensibilidad a todos los antimicrobianos por el método de difusión y valores de CIM por debajo de los puntos de corte para PEN, TMS y CLI. Se identificaron cepas resistentes a ENR y STR, con CIM50, CIM9o y rangos de CIM por encima de los puntos de corte. Los resultados confirman que la PEN podría utilizarse empíricamente, ya que las cepas circulantes en Buenos Aires no mostraron resistencia a este antimicrobiano. Se enfatiza en la relevancia del uso racional de los antibióticos para lograr éxito terapéutico, evitar la cronicidad, la recidiva de infecciones y la aparición de resistencia.

Streptococcus equi subsp. equi is the etiologic agent of strangles, an infectious disease affecting the upper respiratory tract and head and neck lymph nodes of equines. Routine antimicrobial therapy includes penicillin (PEN) as antibiotic of first choice. Streptococci are usually susceptible to PEN and only a few antimicrobial studies had been performed. The aim of this work was to study the antimicrobial susceptibility profile of S. equi from Buenos Aires, Argentina. Ninety-two isolates were studied by the single disk method to PEN, cefotaxime, erythromycin (ERY), tetracycline, enrofloxacin (ENR), trimethoprim sulfamethoxazole (TMS), ciprofloxacin, clindamycin (CLI), streptomycin (STR) and florfenicol. Minimum inhibitory concentration (MIC) to PEN and antibiotics with resistance and intermediate susceptibility were tested. High percentages of susceptibility were obtained by the disk diffusion method and MIC values of PEN, TMS and CLI were found to be under the breakpoint values. Resistant strains of ENR and STR with MIC50, MIC90 and MIC ranges above breakpoints were identified. These findings confirm that PEN may be used empirically because resistant strains were not found in Buenos Aires. Emphasis is placed on the rational use of antibiotics to achieve therapeutic success, to prevent chronicity, recurrence of infections and the emergence of resistance.

Clinical features of children with burkholderia gladioli bloodstream infection and drug susceptibility of burkholderia gladioli / 第二军医大学学报

Objective To explore the clinical features of children with Burkholderia gladioli (B. gladioli) bloodstream infection and the drug susceptibility of B. gladioli. Methods The clinical data of 63 children with B. gladioli bloodstream infection admitted to Wuhan Children’s Hospital, Tongji Medical College of Huazhong University of Science and Technology from Jan. 2015 to Jan. 2016 were retrospectively analyzed, and 81 children with non-bacterial infectious diseases in the same period were enrolled as controls. The C-reactive protein (CRP) level, procalcitonin (PCT) level and white blood cell (WBC) counts of children were compared between the two groups. B. gladioli was isolated from the blood samples of children and cultured for preliminary identifying by Phoenixtm100 automatic microorganism identification instrument and confirming by MALDI-TOP MS mass spectrometer. The in vitro antimicrobial susceptibility testing of B. gladioli were performed by Kirby-Bauer method. Results The children infected with B. gladioli were mainly infants, with 52 cases (82.54%) being three years old or below. All cases had serious underlying diseases, including bronchitis, pneumonia and leukemia. Compared with the control group, the PCT level, CRP level, and WBC counts in the children of the B. gladioli group were significantly increased (all P<0.05). According to the drug susceptibility criteria of Pseudomonas aeruginosa, the isolated B. gladioli was highly sensitive to amikacin, gentamycin, tetracycline, minocycline, cotrimoxazole, ciprofloxacin, levofloxacin, imipenem, meropenem, cefepime, piperacillin, piperacillin/tazobactam and cefoperazone/sulbactam, but had low resistance to chloramphenicol and high resistance to ceftazidime and aztreonam. Conclusion Children infected with B. gladioli are mainly infants aged≤3 years old, with low immunity and poor resistance. Blood culture and CRP level, PCT level and WBC counts can be used as diagnostic indicators of disease outcomes. Piperacillin/tazobactam and cefoperazone/sulbactam should be the first selected drugs for the treatment of children with B. gladioli bloodstream infection.

Sensibilidad a los antimicrobianos de aislamientos de Helicobacter pylori aislados de lesiones gástricas / Antimicrobial susceptibility of Helicobacter pylori strains isolated from gastric lesions

Se evaluó la sensibilidad a los antimicrobianos de 30 aislamientos de Helicobacter pylori aislados de biopsias gástricas mediante los métodos de difusión por discos y tiras de E-test. Los antimicrobianos evaluados fueron amoxicilina, claritromicina, metronidazol y ciprofloxacina. No se encontraron cepas resistentes a amoxicilina, el 17% (5/30) fueron resistentes a claritromicina, el 20% (6/30) a ciprofloxacina por ambos métodos, y el 37% (11/30) a metronidazol por E-test. Si bien el número de cepas estudiadas fue reducido, hubo una sola discrepancia en la interpretación de la sensibilidad cuando se compararon ambos métodos: el metronidazol fue categorizado como sensible por E-test e intermedio por el método de difusión por discos. No pudo determinarse una asociación estadísticamente significativa entre el tipo de lesión histológica y el patrón de resistencia encontrado.

Antimicrobial susceptibility was evaluated by two diffusion methods: E-test strips to determine minimum inhibitory concentration (MIC) and disk diffusion for amoxicillin, clarithromycin, metronidazole and ciprofloxacin in 30 Helicobacter pylori strains isolated from gastric biopsies. No strains were resistant to amoxicillin, 17% (5/30) were resistant to clarithromycin, 20% (6/30) ciprofloxacin by both methods, and 37% (11/30) to metronidazole by the E-test. Although the number of strains studied was reduced, there was a single mismatch in interpreting susceptibility when both methods were compared; the same mismatch was observed for metronidazole, being categorized as sensitive by the E-test and as intermediate by disk diffusion. No association between the histological type of lesion and the resistance pattern found could be determined.

Study on in vitro drug susceptibility test of biomembrane-producing Klebsiella pneumoniae / 国际检验医学杂志

Objective To study the difference of in vitro drug susceptibility test of biomembrane-producing Klebsiella pneumoni-ae to provide accurate drug reference for clinical treatment.Methods The drug susceptibility test was carried out in clinically isola-ted and screened16 strains of biomembrane-producing Klebsiella pneumoniae by K-B paper diffusion method ,and the results at 24 , 48 ,72 h were recorded.Then the strains were reproduced for several generations until not producing biofilm.Then the above opera-tions were taken again.Finally ,the results of twice drug susceptibility tests were performed the contrastive analysis.Results The mm number of inhibition zone of biomembrane-producing Klebsiella pneumoniae at 24 h had statistical difference compared with that at 48 ,72 h(P<0.05).Conclusion When the in vitro drug susceptibility test of biomembrane-producing Klebsiella pneumoniae is conducted by K-B paper diffusion method ,it is suitable to report the results after 48 h ,this has a certain reference value for pre-venting this bacterium.

Antimicrobial susceptibility of Brazilian Clostridium difficile strains determined by agar dilution and disk diffusion

Abstract Clostridium difficile is a leading cause of diarrhea in hospitalized patients worldwide. While metronidazole and vancomycin are the most prescribed antibiotics for the treatment of this infection, teicoplanin, tigecycline and nitazoxanide are alternatives drugs. Knowledge on the antibiotic susceptibility profiles is a basic step to differentiate recurrence from treatment failure due to antimicrobial resistance. Because C. difficile antimicrobial susceptibility is largely unknown in Brazil, we aimed to determine the profile of C. difficile strains cultivated from stool samples of inpatients with diarrhea and a positive toxin A/B test using both agar dilution and disk diffusion methods. All 50 strains tested were sensitive to metronidazole according to CLSI and EUCAST breakpoints with an MIC90 value of 2 μg/mL. Nitazoxanide and tigecycline were highly active in vitro against these strains with an MIC90 value of 0.125 μg/mL for both antimicrobials. The MIC90 were 4 μg/mL and 2 μg/mL for vancomycin and teicoplanin, respectively. A resistance rate of 8% was observed for moxifloxacin. Disk diffusion can be used as an alternative to screen for moxifloxacin resistance, nitazoxanide, tigecycline and metronidazole susceptibility, but it cannot be used for testing glycopeptides. Our results suggest that C. difficile strains from São Paulo city, Brazil, are susceptible to metronidazole and have low MIC90 values for most of the current therapeutic options available in Brazil.

Toxicological, phytochemical, and antibacterial assessment of Chlorella vulgaris and Spirulina platensis powder in albino rats. A preliminary study

Objectives: To describe acute toxicity, antibacterial activity and phytochemical assessment of Chlorella vulgaris and Spirulina platensis powders. Material and Methods: FeCl3 test, Wagner test, Keller Killiani test, frothing test, alkaline solution and dilute acid; concentrated sulphuric acid were used for phytochemical analysis. Antibacterial screening of the extracts was conducted using the disc gel diffusion method in E. coli, S. aureus and B. cereus clinical strains. In order to evaluate acute toxicity and its effects on haematological and biochemical parameters; 15 albino rats were grouped into five groups: I (powder of aqueous extract of Chlorella vulgaris), II (powder of methanol extract of Chlorella vulgaris), III (powder of aqueous extract of Spirulina platensis), IV (powder of methanol extract of Spirulina platensis) and V (control). The dosage was 25g/day/rat. After six days, haematological and biochemical parameters and gross pathologic changes were evaluated. Results: Alkaloids and flavonoids were detected from the methanol extracts of both Chlorella vulgaris and Spirulina platensis (Arthrospira). Only cardiac glycosides and steroids were detected from Spirulina's extracts. Chlorella vulgaris extracts significantly inhibited B. cereus. Rats fed with Chlorella vulgaris and Spirulina platensis powder showed an increase in white blood cell counts and haemoglobin level compared to negative control rats (p<0.001). Serum glumatic oxalate transaminase (SGOT) and serum glutamate pyruvate transaminase (SGPT) had normal values but significative differences between groups (p<0.001). Conclusion: This powder is rich in bioactive phytochemicals but only Chlorella's extracts have shown antibacterial effect. Signs of toxicity weren't found in any parameter.

Objetivos: Describir la toxicidad aguda, efecto antibacteriano y análisis fitoquímico de los polvos de Chlorella vulgaris y Spirulina platensis. Materiales y métodos: Se realizaron las pruebas de FeCl3, Keller Killiani, de saponinas, solución alcalina y de concentración de ácido sulfúrico para el análisis fitoquímico. El efecto antibacteriano de los extractos fue evaluado mediante el método de difusión con discos en cepas de E. coli, S. aureus y B. cereus. Para evaluar la toxicidad aguda y los efectos del polvo en parámetros hematológicos y bioquímicos, se agruparon 15 ratas albinas en cinco grupos: I (polvo de extracto acuoso de Chlorella vulgaris); II (polvo de extracto metanólico de Chlorella vulgaris); III (polvo de extracto acuoso de Spirulina platensis); IV (polvo de extracto metanólico de Spirulina platensis), y V (grupo control). La dosis usada fue de 25 g/día/rata. Después de seis días, se evaluaron todos los parámetros y cambios macroscópicos en los órganos. Resultados: Se encontraron alcaloides y flavonoides en los extractos metanólicos de Chlorella vulgaris y Spirulina platensis (Arthrospira). Se detectaron glucósidos cardiacos y esteroides en los extractos de Spirulina platensis. Los extractos de Chlorella vulgaris inhibieron el crecimiento de Bacillus cereus. Las ratas alimentadas con los polvos de Chlorella vulgaris y Spirulina platensis incrementaron el conteo de leucocitos y los valores de hemoglobina comparados con el grupo control (p<0,001). Las transaminasas (SGOT y SGPT) se encontraron en valores normales, pero con diferencias significativas entre los grupos (p<0,001). Conclusiones: Estos polvos son ricos en componentes fitoquímicos activos, pero solo los extractos de Chorella vulgaris mostraron efecto antibacteriano. No se encontraron signos de toxicidad aguda en ningún parámetro.

Difference in antimicrobial susceptibility of common clinical pathogens to different ratios of cefoperazone/sulbactam antimicrobial disks / 中国感染控制杂志

Objective To understand the antimicrobial resistance of common clinical pathogens to antimicrobial disks containing different ratios of cefoperazone/sulbactam,so as to provide basis for rational application of cefoper-azone/sulbactam in clinic.Methods 1 141 pathogens isolated from clinical specimens in a hospital in the first half year of 2014 were collected,disk diffusion method was adopted to detect antimicrobial activity of two kinds of cef-operazone/sulbactam disks (70/35 μg and 75/75 μg).Results Of 1 141 pathogenic strains,675 (59.16%)were En-terobacteriaceae,447 (39.18%)were non-fermentative bacteria,and 19 (1 .66%)were other gram-negative bacilli. Resistance rates of pathogens to 70/35μg and 75/75 μg cefoperazone/sulbactam antimicrobial disks were as follows:extended-spectrumβ-lactamases(ESBLs)-producing Escherichia coli (n=221)were 7.69% and 2.26% respective-ly,ESBLs-producing Klebsiella pneumoniae (n=92)10.87% and 3.26% respectively,imipenem-resistant Acineto-bacter baumannii (IRAB,n=295)54.92% and 11 .19%respectively;there were significant differences in antimicrobial activity between two ratios of antimicrobial disks(P 0.05).Conclusion Antimicrobial activity of two different ratios of cefoperazone/sulbactam antimicrobial disks to ESBLs-producing Enterobacteriaceae and IRAB is different,attention should be paid to ratios of cefoperazone/sulbactam during the treatment ,so as to achieve the desired therapeutic effect.

Nosocomial candidiasis in Rio de Janeiro State: Distribution and fluconazole susceptibility profile

One hundred and forty-one Candida species isolated from clinical specimens of hospitalized patients in Rio de Janeiro, Brazil, during 2002 to 2007, were analized in order to evaluate the distribution and susceptibility of these species to fluconazole. Candida albicans was the most frequent species (45.4%), followed by C. parapsilosis sensu lato (28.4%), C. tropicalis (14.2%), C. guilliermondii (6.4%), C. famata (2.8%), C. glabrata (1.4%), C. krusei (0.7%) and C. lambica (0.7%). The sources of fungal isolates were blood (47.5%), respiratory tract (17.7%), urinary tract (16.3%), skin and mucous membrane (7.1%), catheter (5.6%), feces (2.1%) and mitral valve tissue (0.7%). The susceptibility test was performed using the methodology of disk-diffusion in agar as recommended in the M44-A2 Document of the Clinical and Laboratory Standards Institute (CLSI). The majority of the clinical isolates (97.2%) was susceptible (S) to fluconazole, although three isolates (2.1%) were susceptible-dose dependent (S-DD) and one of them (0.7%) was resistant (R). The S-DD isolates were C. albicans, C. parapsilosis sensu lato and C. tropicalis. One isolate of C. krusei was resistant to fluconazole. This work documents the high susceptibility to fluconazole by Candida species isolated in Rio de Janeiro, Brazil.

Incidence of carbapenem resistant nonfermenting gram negative bacilli from patients with respiratory tract infections among intensive care units.

Background: Non fermenting gram negative bacilli that were considered to be contaminants in the past have now emerged as important healthcare- associated pathogens. Pseudomonas aeruginosa and Acinetobacter species are now known to be the common nosocomial pathogens. Carbapenems are one of the essential antibiotics in the armamentarium against, serious nosocomial infections. Development of resistance against these is a cause of concern. Misuse and inappropriate duration of antibiotic therapy helps in development of resistance. Methods: A total of 200 endo tracheal aspirates and sputum samples were collected from patients of all age groups with clinical evidence of lower respiratory tract infection from Medical, surgical, pediatric ICUS. Non fermenting gram negative bacilli isolated and identified according to CLSI guidelines and antibiotic sensitivity test was performed by Kirby Bauer disc diffusion method. Results: Out of 200 samples 50 Acinetobacter spp. and 38 Pseudomonas aeruginosa were isolated. Among 38 Pseudomonas isolates (42%) 16 were resistant to imipenem and 11 (29%) were resistant to meropenem. Among 50 Acinetobacter isolates 14 (28%) were resistant to imipenem and 12 (24%) were resistant to meropenem. Conclusions: Our study documents an increase in the carbapenem resistance. Reduction in antimicrobial resistance in the ICUS has been a goal for all ICUS as it improves outcome and cost of patient care. Carbapenem must be used judiciously to prevent further resistance or else this would erode the strength of life saving antibiotics.

Speciation of clinically significant coagulase negative staphylococci and their antibiotic resistant patterns in a tertiary care hospital.

Background: Coagulase negative Staphylococci (CONS) are normal human microbiota and sometimes cause infections, often associated with implanted devices, such as joint prosthesis, shunts and intravascular catheters, especially in very young, old and immunocompromised patients. These infections are difficult to treat because of the risk factors and the multiple drug resistant nature of the organisms. The study is undertaken to speculate CONS isolates from various clinical samples and to determine antibiotic susceptibility pattern of CONS by Kirby Bauer disc diffusion method. Methods: A total of 134 clinically significant CONS isolated from pus, urine, blood, fluid, sputum, ear swabs, endotracheal tube, ophthalmic, semen and nail samples. These isolates initially identified by colony morphology, Gram staining, catalase test, slide coagulase test, tube coagulase test and mannitol fermentation. Speciation of CONS was done by novobiocin resistance test, urease activity, ornithine decarboxylase and aerobic acid production from mannose. Results: S. epidermidis is the most frequent isolate 62 (46.3%) followed by S. saprophyticus 38(28.4%), S. haemolyticus 27(20.1%), S. lugdunensis 3(2.2%). S. warneri 3(2.2%), S. cohinii 1(0.7%). Antibiotic susceptibility testing of the isolates showed maximum resistance to penicillin 128 (95.5%) and ampicillin118 (88%) followed by erythromycin 96 (71.6%), cefoxitin 89 (66.4%), gentamicin 33(24.6%), piperacillin & tazobactam 31(23.8%), amoxicillin & clavulanic acid 25 (18.7%), linezolid 23 (17.2%), levofloxacin 9 (6.7%), vancomycin & teicoplanin 2 (1.5%), tigecycline 1 (0.7%). Conclusion: S. epidermidis is the more common isolate identified and CONS are often resistant to multiple antibiotics (Penicillin, ampicillin) & glycopeptides have been considered as the drugs of choice for the management of infections caused by these organisms.