In vitro susceptibility to fosfomycin in clinical and environmental extended-spectrum beta-lactamase producing and/or ciprofloxacin-non-susceptible Escherichia coli isolates

ABSTRACT Extended-spectrum beta-lactamase producing and ciprofloxacin-non-susceptible Escherichia coli are clinical and environmental issues. We evaluated the susceptibility profile of fosfomycin in non-susceptible E. coli isolated from urine and the environment. We measured the activity of fosfomycin against 319 and 36 E. coli strains from urine and environmental isolates, respectively, collected from rivers. Fosfomycin resistance profiles were investigated using the minimal inhibitory concentration (MIC), according to the Clinical and Laboratory Standards Institute (CLSI) and the European Committee for Antimicrobial Susceptibility Testing (EUCAST) guidelines. Antibiotic susceptibility testing revealed that 5% and 6.6% of urine samples were non-susceptible to fosfomycin according to CLSI and EUCAST guidelines, respectively. The fosfomycin MIC50/90 was 0.5/4 mg/L. Of the 36 E. coli isolates from river water, 11.1% and 13,8% were non-susceptible to fosfomycin according to CLSI and EUCAST, respectively (range ≤0.25 ≥512 mg/L). All the isolates with MIC ≥512 mg/L for fosfomycin showed the fosA3 gene. Fosfomycin resistance was more frequent in the environment than in clinical samples.

Evaluation of in-vitro susceptibility of ß-lactam-resistant Gram-negative bacilli to ceftazidime-avibactam and ceftolozane-tazobactam from clinical samples of a general hospital in southern Brazil

ABSTRACT Background: The spread of carbapenemase- and extended-spectrum β-lactamase (ESBL)-producing gram-negative bacilli (GNB) represent a global public health threat that limits therapeutic options for hospitalized patients. This study aimed to evaluate the in-vitro susceptibility of β-lactam-resistant GNB to ceftazidime-avibactam (C/A) and ceftolozane-tazobactam (C/T), and investigate the molecular determinants of resistance. Methods: Overall, 101 clinical isolates of Enterobacterales and Pseudomonas aeruginosa collected from a general hospital in Brazil were analyzed. Susceptibility to the antimicrobial agents was evaluated using an automated method, and the minimum inhibitory concentrations (MIC50/90) of C/A and C/T were determined using Etest®. The β-lactamase-encoding genes were investigated using polymerase chain reaction. Results: High susceptibility to C/A and C/T was observed among ESBL-producing Enterobacterales (100% and 97.3% for CLSI and 83.8% for BRCAST, respectively) and carbapenem-resistant P. aeruginosa (92.3% and 87.2%, respectively). Carbapenemase-producing Klebsiella pneumoniae exhibited high resistance to C/T (80%- CLSI or 100%- BRCAST) but high susceptibility to C/A (93.4%). All carbapenem-resistant K. pneumoniae isolates were susceptible to C/A, whereas only one isolate was susceptible to C/T. Both antimicrobials were inactive against metallo-β-lactamase-producing K. pneumoniae isolates. Resistance genes were concomitantly identified in 44 (44.9%) isolates, with bla CTX-M and bla SHV being the most common. Conclusions: C/A and C/T were active against microorganisms with β-lactam-resistant phenotypes, except when resistance was mediated by metallo-β-lactamases. Most C/A- and C/T-resistant isolates concomitantly carried two or more β-lactamase-encoding genes (62.5% and 77.4%, respectively).

NDM-beta-lactamase-1: Where do we stand?

Multidrug-resistant (MDR) Gram-negative bacilli (GNB) have been playing havoc in the field of nosocomial as well as community-acquired infections. Of particular concern are the carbapenem-resistant GNBs, belonging to Enterobacteriaceae and encoding for New Delhi metallo-beta-lactamase-1 (NDM-1) gene. These strains spread rapidly and horizontally in the population, thus exhibiting MDR traits as these can harbour several resistance encoding genes to almost all antimicrobial groups. Several predisposing factors are responsible towards its spread, viz. excessive antibiotic usage, improper aseptic conditions by healthcare workers, lack of awareness, abruptly discontinuing medication course, alternative medications and vector-borne factors contributing to the unchecked harbouring of these super bugs in India. Thus, a bugle call has already been sounded worldwide especially in India, where the country has taken serious cognizance to build up strategy via implementation of several national programs to combat antimicrobial resistance covering human, animal, agriculture and environmental aspects. As there is an exponential rise in variants of NDM-1 harbouring strains, molecular epidemiological investigations of these strains using genotyping techniques are of paramount importance for a better understanding of this rampant spread and curbing resistance thereafter. This review explores the urgent need to develop a cost-effective, rapid molecular assay, viz. the loop-mediated isothermal amplification method for field detection of MBL harbouring bacterial strains, especially NDM-1 and its variants, thus targeting specific carbapenemase genes at a grass root level even to the remote and rural regions of the country.

Epidemiological characteristics and risk prediction model of pulmonary infection in elderly patients in a hospital in Hebei Province / 公共卫生与预防医学

Objective To analyze the epidemiological characteristics and influencing factors of pulmonary infection in the elderly, and to construct a risk prediction model. Methods Stratified cluster sampling was used to randomly select 683 elderly patients in Zhangjiakou First Hospital as the investigation subjects. Sputum specimens were collected and sent for bacterial isolation, culture, identification, and drug sensitivity test. According to whether the patients had pulmonary infection, they were divided into pulmonary infection group (n=315) and non-pulmonary infection group (n=368). The clinical data of the two groups such as age, sex, COPD, and ICU admission were analyzed. Univariate analysis and logistic regression analysis were used to analyze the influencing factors of pulmonary infection in elderly patients, and a risk prediction model was established. Results A total of 331 strains of pathogenic bacteria were detected in 315 patients with pulmonary infection, and there were 207 strains (62.54%) of gram-negative bacteria detected, mainly including 95 strains (28.70%) of Acinetobacter baumannii and 71 strains (21.45%) of Klebsiella pneumoniae. There were 169 strains (26.28%) of gram-positive bacteria detected, mainly 68 strains (20.54%) of Staphylococcus aureus. In addition, there were 25 strains of fungi (7.55%). There were no significant differences in gender, smoking history, history of COPD, asthma, and stroke between the two groups (P>0.05). The proportion of patients aged≥70, mechanical ventilation, admission to ICU and recent respiratory tract infection in the experimental group was significantly higher than that in the control group (P<0.05). Multivariate logistic regression analysis showed that age, smoking history, mechanical ventilation, and ICU admission were independent risk factors for pulmonary infection in elderly patients (P<0.05). According to the above four independent influencing factors and corresponding regression coefficient of each factor, the prediction model of pulmonary infection in elderly patients was constructed, Z=-5.948+1.198× (age) +1.281×(smoking history) +2.029×(mechanical ventilation) +1.211×(ICU admission). Conclusion Lung infection in elderly patients in our hospital is dominated by gram-negative bacilli. Antibiotics should be rationally selected according to drug sensitivity results. Age≥70 years old and COPD can increase the risk of pulmonary infection in elderly patients, and the prediction model constructed can effectively predict the occurrence of pulmonary infection in elderly patients.

Molecular epidemiology and drug resistance of Acinetobacter baumannii isolated from a regional hospital in the Brazilian Amazon region

Abstract INTRODUCTION: In this study, we report a clonal dissemination of carbapenem resistant Acinetobacter baumannii isolates due to the acquisition of blaOXA-23 in a regional hospital located in Brazilian Amazon Region. METHODS: The isolates were identified by MALDI-TOF and the carbapenemase-encoding genes were detected by multiplex-PCR. The genetic similarity was investigated by pulsed-field gel electrophoresis (PFGE). RESULTS: Only 10 (55.6%) isolates harbored the gene bla OXA-23. PFGE analysis revealed that these isolates belong to a single clone. CONCLUSIONS: This dissemination strategy indicates the need for surveillance, adoption of control procedures defined in guidelines, and the careful administration of antimicrobials should be reinforced.

Distribution of pathogenic bacteria and analysis of drug sensitivity in acute dacryocystitis / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To explore the pathogenic bacteria and drug resistance of acute dacryocystitis, and to provide a guide for rational clinical medication.<p>METHODS: Lacrimal sac pus samples from 80 acute dacryocystitis cases were collected for bacterial culture and drug sensitivity test in Hebei Provincial Eye Hospital from January 2014 to October 2019. The change of detection rate of pathogenic bacteria in different years, the species of pathogenic bacteria of acute dacryocystitis, the main pathogenic bacteria, drug sensitivity and drug resistance of acute dacryocystitis, and the average detection rate of pathogenic bacteria in acute dacryocystitis were analyze.<p>RESULTS:Totally 56 samples were positive for pathogenic bacteria, including 55 cases of bacteria and 1 case of fungi. The average detection rate was 70%. The detection rate of pathogenic bacteria strains was gradually decreasing year by year, and there were various types of pathogenic bacteria strains detected from samples. In addition, Gram-positive cocci was the main pathogenic bacteria of acute dacryocystitis, accounting for 68%(38 cases), of which, staphylococcus aureus accounted for 38%(21 cases). What's more, most Gram-positive cocci were sensitive to rifampin, levofloxacin, and chloramphenicol, and Gram-negative bacilli were more sensitive to tobramycin, levofloxacin, ciprofloxacin, and gentamicin. Fifty-five cases of bacterial samples were obviously resistant to the first and second generation cephalosporins.<p>CONCLUSION: Gram-positive cocci constitute the main pathogenic bacteria of acute dacryocystitis, and levofloxacin can be used as the first choice of topical antibiotics for the treatment of acute dacryocystitis.

Presencia de Bacilos Gram-negativos y Candida albicans en provisionales de polimetilmetacrilato (PMM)en pacientes de Clínica Integrada de la Universidad Autónoma de Asunción / Presence of Gram-negative bacilli and Candida albicans in provisional polymethylmethacrylate in patients of the Integrated Clinic of the Autonomous University of Asunción

Las resinas a base de polimetilmetacrilato (PMM) son una solución para la reposición de estructuras dentarias. Este material ha sido muy utilizado debido a su buena estética, pero las rugosidades, grietas y defectos de este material son propicios para la proliferación de microrganismos que podrían constituir un riesgo para la salud de los pacientes. Estudio observacional descriptivo de corte transversal, donde se tomaron muestras de provisorios de PMM de 20 pacientes de la cátedra de Clínica Integrada de Odontología de la Universidad Autónoma de Asunción. Los datos sobre el crecimiento de los microorganismos fueron anotados en planillas Excel para análisis estadísticos. De los 20 pacientes que participaron en esta investigación, 50% fueron de sexo femenino y 50% masculino, el promedio de edad fue de 32,35 años (DE±11,94). Se analizaron un total de 7 pónticos (6 pónticos de 3 piezas y 1 de 6 piezas) y 19 coronas unitarias, el tiempo de permanencia en boca fue de entre 4 a 20 semanas con una media de 8,6 semanas. El 65% de las muestras dio positivo al cultivo microbiológico. En algunas muestras se aislaron más de un género de microorganismos. Se aislaron 5 especies de bacterias Gram-negativas, la más frecuente fue K. pneumoniae con un 40%. Se aisló C. albicans en un 10% de las muestras. En el proceso de elección de los materiales para rehabilitación es fundamental considerar la situación global de cada paciente, pues exponerlos a un material con grandes capacidades retentivas de microrganismos conlleva un peligro

Polymethylmethacrylate (PMM) based resins are a solution for the replacement of dental structures. This material has been widely used due to its good aesthetics, but the roughness, cracks and defects of this material are propitious for the proliferation of microorganisms that could constitute a risk to the health of patients. This was a descriptive cross-sectional observational study, where samples of PMM provisionals were taken from 20 patients of the Department of Integrated Dental Clinic of the Autonomous University of Asunción. Data on the growth of microorganisms were recorded in Excel spreadsheets for statistical analysis. Of the 20 patients who participated in this research, 50% was female and 50% male, and the average age was 32.35 years (SD±11.94). Seven pontics (6 pontics of 3 pieces and 1 of 6 pieces) and 19 unit crowns were analyzed, the time spent in the mouth was between 4 to 20 weeks with an average of 8.6 weeks. Sixty-five percent of the samples tested positive in the microbiological culture. In some samples, more than one genus of microorganisms was isolated. Five species of Gram-negative bacteria were isolated, the most frequent was Klebsiella pneumoniae with 40%. Candida albicans was isolated in 10% of the samples. In the process of choosing materials for rehabilitation, it is essential to consider the overall situation of each patient, since exposing them to a material with high retention capacities of microorganisms carries a danger

Primer reporte de bacterias y dinoflagelados marinos luminiscentes del Parque Nacional Isla del Coco, Costa Rica

Introducción: La bioluminiscencia es la capacidad de ciertos organismos para transformar la energía química en energía lumínica mediante varios procesos bioquímicos. Objetivo: El aislamiento e identificación por primera vez de bacterias luminiscentes en agua marina superficial y la identificación de dinoflagelados luminiscentes marinos del Parque Nacional Isla del Coco, Costa Rica. Metodología: Se colectaron muestras de agua marina obtenida por buceo a 20 m y a nivel superficial de 13 sitios en la Isla del Coco, Costa Rica. Por otra parte, se analizaron muestras de fitoplancton colectadas desde la superficie hasta los 30 m de profundudad en los alrededores de 8 sitios de la Isla del Coco, y se determinaron varias especies luminiscentes pertenecientes a los géneros Ornithocercus y Ceratocorys. Resultados: Se logró obtener 7 aislados bacterianos luminiscentes, se identificaron y caracterizaron bioquímicamente mediante una plataforma automatizada (Vitek) con altos niveles de confianza, se ubicaron taxonómicamente dentro del género Vibrio,2 especies: V. alginolyticus y V. parahaemolyticus, además, algunos aislados presentaron resistencia al antibiótico ampicilina y 100% capacidad hemolítica. Esta investigación muestra evidencia de la presencia de especies microscópicas marinas en Isla del Coco, Costa Rica, capaces de presentar el fenómeno de la luminiscencia, por lo que profundizar en su estudio sería relevante en cuanto a la importancia de estos microorganismos en la producción de metabolitos secundarios y como indicadores de floraciones algales nocivas, por lo que se hace necesario realizar más investigación científica para determinar su potencial biotecnológico. Conclusiones: De la misma forma, los resultados obtenidos en esta investigación sugieren expandir las localidades de colecta y aislamientos de microorganismos luminiscentes, acompañado de una caracterización bioquímica y molecular, con el fin de explorar la diversidad microbiana asociada a eventos de luminiscencia y determinar los ambientes en el que estas especies se desarrollan.

Introduction: Bioluminescence is the ability of certain organisms to transform chemical energy into light energy through various biochemical processes. Objective: Isolation and identification for the first time of luminescent bacteria of superficial marine water, and the identification of marine luminescent dinoflagellates of Isla del Coco National Park, Costa Rica. Methods: Samples of seawater obtained by diving at 20 m and at a surface level of 13 sites were collected. On the other hand, phytoplankton samples collected from the surface up to 30 m deep were analyzed in the surroundings of 8 sites of Cocos Island, and several luminescent species belonging to the genera Ornithocercus and Ceratocorys were determined. Results: Seven luminescent bacterial isolates were obtained, they were identified and characterized biochemically by means of an automated platform (Vitek) with high levels of confidence, they were taxonomically located within the genus Vibrio, 2 species: V. alginolyticus and V. parahaemolyticus, in addition, some isolates presented resistance to the antibiotic ampicillin and 100% hemolytic capacity. This research shows evidence of the presence of marine microscopic species in Cocos Island, Costa Rica, capable of presenting the phenomenon of luminescence, so that further study would be relevant in terms of the importance of these microorganisms in the production of metabolites secondary and as indicators of harmful algal blooms, so it is necessary to conduct more scientific research to determine their biotechnological potential. Conclusions: In the same way, the results obtained in this investigation suggest expanding the collection and isolation of luminescent microorganisms, accompanied by a biochemical and molecular characterization, in order to explore the microbial diversity associated with luminescence events and determine the environments in which that these species develop.

Comparison of Hemodynamic Response and Vasopressor Requirement Following Spinal Anesthesia between Normotensive and Hypertensive Women Undergoing Elective Cesarean Section

Introduction: Spinal anesthesia (SA) is the technique of choice in cesarean sections, but it is not widely accepted in hypertensiondue to fear of sudden and extensive sympathetic blockade. Sympathetic blockade induced hypotension may occur in up to64–100% of pregnant women who have been given spinal anesthesia for cesarean delivery, especially when hyperbaric solutionsare used. Severely pre-eclamptic patients were previously believed to be at high risk of severe hypotension, with maternaland fetal consequences because of reduced plasma volume and because of the need to limit i.v. fluids to avoid iatrogenicpulmonary edema.Methodology: The present study, “comparison of hemodyanamic response and vasopressor requirement following spinalanesthesia between normotensive and hypertensive women undergoing elective cesarean section” 100 women of age20–35 years, the American Society of Anesthesiologists physical Status Ι and ΙΙ carrying a singleton pregnancy and scheduledto have elective cesarean section in Netaji Subhash Chandra Bose Medical College, Jabalpur, were enrolled into two groups.GroupA: 50 were normotensive women and Group B: 50 were hypertensive women. All patients received a standard subarachnoidblock under all aseptic precautions with 12.5 mg 0.5% hyperbaric bupivacaine.Results: Based on the data from our study, it could be concluded that after spinal anesthesia in patients undergoing electivecesarean section-hypertensive group of parturients had less fall in mean systolic blood pressure (SBP), diastolic BP, and meanarterial BP in comparison to normal healthy pregnant women which were statistically significant (P < 0.05). Hypertensive group ofpatients required less ephedrine to treat hypotension in comparison to normotensive patients which were statistically significant(P < 0.05). The incidence of hypotension was almost 7 times less in hypertensive parturients than healthy parturients (oddsratio = 23.14, relative risk of hypotension in Group A = 7.2, confidence interval = 7.6–70.3).Conclusion: To summarize, our results showed that hypotension following SA administered for cesarean section wassignificantly less in hypertensive patient than in healthy pregnant women. In addition, vasopressor requirements were also lessin hypertensive parturients and neonatal outcome was comparable between the two groups. Therefore, subarachnoid blockis an acceptable technique to perform in hypertensive parturients due to its virtue of simplicity, rapidity, cost-effectiveness,and intensity of block.

Bacteriological Profile and Antimicrobial Susceptibility Patterns of Bacteria Isolated from Surgical Site Infections of Patients Attending a Tertiary Care Hospital

Introduction: Surgical site infections (SSIs) are one of themajor causes of morbidity and mortality in developing countriesdespite recent advances in aseptic techniques. The SSIs dueto emerging multidrug resistance (MDR) bacteria isolates areconsidered as grave threats to the public health worldwide.Each hospital has specific type of microbial flora from whichinfection initiates. In such condition microorganism showsunique type of antibiotic susceptibility and resistance pattern.In this study we report on the microbiological spectrum ofSSIs and the antimicrobial susceptibility pattern with a viewto provide guide to the clinicians for making rational decisionover the choice of antibiotics in the management of surgicalsite infection.Material and Methods: This cross-sectional study wascarried out in a tertiary care hospital and the 560 sampleswere collected, processed in the microbiology laboratory andevaluated for the study.Results: Out of 376 growth positive samples, Gram NegativeBacilli (GNB) were isolated from 271 (72%) samples andGram Positive Cocci (GPC) were isolated from 105 (28%)samples. Among the isolated GNB, only 5 to 10% weresensitive to third generation Cephalosporins. Sensitivity toFluroquinolones (Ciprofloxacin and Levofloxacin) was alsolow (Only 5% to 10% were sensitive). Only 3 to 15% of theGNB were found sensitive to Co-amoxiclav and 6.5% to 23%were sensitive to Ampicillin-Sulbactam. About 60% of thePseudomonas aeruginosa and about 40% of the Klebsiellaspp and Acinetobacter baumanii were found resistant toMeropenem.Conclusion: Gram Negative Bacilli predominated overGram Positive Cocci in surgical site infections in our setup. Very low sensitivity to 3rd generation Cephalosporins,Ampicillin, Co-amoxiclav and Fluroquinolones was notedamong GNB isolates and an increasing pattern of resistanceto Aminoglycosides and Carbapenems was also noted amongMDR Pseudomonas aeruginosa and Acinetobacter baumaniiisolates. More than 50% of the MDR Acinetobacter spp.were was found sensitive to Ampicillin- Sulbactam andMinocycline.

Analysis of Distribution and Drug Resistance of Non-fermentative Gram-negative Bacilli in a Tertiary Hospital from 2010 to 2019 / 中国药房

OBJECTIVE：To provide reference for clinical empirical treatme nt of non-fermentative Gram-negative bacilli （NFGNB）infection. METHODS ：All kinds of clinical specimens were collected from Jan. 2010 to Dec. 2019 in a tertiary hospital from Hanzhong city of Shaanxi province ；the distribution and drug resistance of NFGNB were analyzed retrospectively. RESULTS ： A total of 26 386 strains of pathogenic bacteria were detected in the hospital during 2010-2019，including 4 077 strains of NFGNB （15.45％），mainly from patients ≥60 years old （1 836 strains，45.05％）. During the 10 years，the detection rate of NFGNB decreased from 20.14％ in 2010 to 15.36％ in 2019 （P＜0.001）. Acinetobacter baumannii （1 359 strains），Pseudomonas aeruginosa （1 269 strains），Stenotrophomonas maltophilia （447 strains） and Burkholderia cepacia （351 strains） were main pathogens. The detected NFGNB mainly came from hospitalized patients （4 001 strains），and most of them were found in ICU （17.05％），neurosurgery department （14.52％），respiratory department （12.41％），and respiratory tract （66.69％），secretion （7.80％）specimens. The detection rates of A. baumannii and P. aeruginosa in oncology department ，blood specimens and urine specimens showed an overall upward trend ，while the detection rates in ICU of the hospital showed a downward trend （P＜0.05）； the detection rate of P. aeruginosa in neurosurgery department showed an upward trend （P＜0.05），and that of A. baumannii in respiratory department showed an upward trend （P＜0.05）. The resistance rate of A. baumannii to carbapenems increased from about 10％ in 2010 to about 75％ in 2019，and the guyh3201@163.com resistance rate to cephalosporins exceeded 78％. The resistance rates of P. aeruginosa to imipenem and me ropenem were lower than 35％ and 30％ respectively，and the trend of drug resistance did not change significantly （P＞0.05）；the resistance rates to 12 kinds of clinically commonly used antibiotics as piperacillin and aztreonam were lower than 40％. The resistance rate of S. maltophilia to compound sulfamethoxazole showed a decreasing trend （P＜0.001），and the resistance rate to ceftazidime was high （54.70％-74.10％）. The resistance rates of B. cepacia to compound sulfamethoxazole，meropenem and ceftazidime showed a downward trend （P＜0.01），and were lower than 15％ after 2014. CONCLUSIONS：Although the detection rate of NFGNB in our hospital showed a downward trend ，the multi-drug resistance and pan-drug resistance of A. baumannii are serious ，and the resistance rate to carbapenems is increased. Sensitive drugs such as cefoperazone/sulbactam，amikacin，levofloxacin and ceftazidime should be selected for NFGNB infection according to the results of drug sensitivity tests.

Establishment of a database of in vitro combined drug efficacy against multi-drug resistant Gram-negative bacilli / 中华微生物学和免疫学杂志

Objective To study the synergistic and additive effects of commonly used antibiotics on multi-drug resistant Gram-negative bacilli and to establish a database of combined pharmacodynamics in vitro. Methods Seven antibiotics including fosfomycin (PHOS), levofloxacin (LEV), ceftazidime ( CAZ ) , compound sulfamethoxazole ( SMZ ) , piperacillin/tazobactam ( TZP ) , cefoperazone/sulbactam ( SCF) and imipenem ( IMP) were selected and grouped into 21 drug pairs. Based on the results of extended spectrum β-lactamases ( ESBLs) test and modified carbapenem inactivation method ( mCIM) , a total of 172 strains of multidrug-resistant Gram-negative bacilli were divided into four groups:20 strains of carbapenem-resistant Klebsiella pneumoniae ( group A) , 50 strains of pan-resistant Acinetobacter baumannii ( group B) , 62 strains of ESBLs-producing Enterobacter ( group C) and 40 strains of carbapenem-resistant Pseudomonas aeruginosa ( group D) . Chessboard dilution method was used to detect the in vitro combined efficacy of 21 drug pairs on drug-resistant bacteria from the four groups. Whonet 5. 6 was used for statistical analysis. Re-sults All 172 strains were single drug resistant to the seven antibiotics. Results of the combined drug effi-cacy test showed that no antagonism was found in the four groups. In group A, ten drug pairs, especially the combination of PHOS+LEV (30％, 6/20), had synergistic effects and 14 showed partial synergistic effects,but no additive effect was detected. Synergistic effects, partial synergistic effects and additive effects were respectively achieved by 12, ten and three drug pairs in group B. The LEV+SMZ combination had synergis-tic effects against 56％ (28/50) of the strains, which was the highest among all combinations. There were 14, 17 and 16 drug pairs showing synergistic effects, partial synergistic effects and additive effects in group C, respectively, and the strongest synergistic effects were achieved by the IMP+LEV combination (30. 6％, 19/62). There were 12, 14 and 13 drug pairs having synergistic effects, partial synergistic effects and addi-tive effects in group D, respectively, and the strongest synergistic effects were achieved by the IMP+LEV combination (20％, 8/40). Conclusions The combined use of quinolones, carbapenems, sulfonamides and PHOS could have good synergistic effects against multi-drug-resistant gram-negative bacilli. Monitoring the in vitro combined efficacy before treatment would improve the accuracy of antibiotic use and is of great clinical value.

Establishment of a database of in vitro combined drug efficacy against multi-drug resistant Gram-negative bacilli / 中华微生物学和免疫学杂志

Objective@#To study the synergistic and additive effects of commonly used antibiotics on multi-drug resistant Gram-negative bacilli and to establish a database of combined pharmacodynamics in vitro.@*Methods@#Seven antibiotics including fosfomycin (PHOS), levofloxacin (LEV), ceftazidime (CAZ), compound sulfamethoxazole (SMZ), piperacillin/tazobactam (TZP), cefoperazone/sulbactam (SCF) and imipenem (IMP) were selected and grouped into 21 drug pairs. Based on the results of extended spectrum β-lactamases (ESBLs) test and modified carbapenem inactivation method (mCIM), a total of 172 strains of multidrug-resistant Gram-negative bacilli were divided into four groups: 20 strains of carbapenem-resistant Klebsiella pneumoniae (group A), 50 strains of pan-resistant Acinetobacter baumannii (group B), 62 strains of ESBLs-producing Enterobacter (group C) and 40 strains of carbapenem-resistant Pseudomonas aeruginosa (group D). Chessboard dilution method was used to detect the in vitro combined efficacy of 21 drug pairs on drug-resistant bacteria from the four groups. Whonet 5.6 was used for statistical analysis.@*Results@#All 172 strains were single drug resistant to the seven antibiotics. Results of the combined drug efficacy test showed that no antagonism was found in the four groups. In group A, ten drug pairs, especially the combination of PHOS+ LEV (30%, 6/20), had synergistic effects and 14 showed partial synergistic effects, but no additive effect was detected. Synergistic effects, partial synergistic effects and additive effects were respectively achieved by 12, ten and three drug pairs in group B. The LEV+ SMZ combination had synergistic effects against 56% (28/50) of the strains, which was the highest among all combinations. There were 14, 17 and 16 drug pairs showing synergistic effects, partial synergistic effects and additive effects in group C, respectively, and the strongest synergistic effects were achieved by the IMP+ LEV combination (30.6%, 19/62). There were 12, 14 and 13 drug pairs having synergistic effects, partial synergistic effects and additive effects in group D, respectively, and the strongest synergistic effects were achieved by the IMP+ LEV combination (20%, 8/40).@*Conclusions@#The combined use of quinolones, carbapenems, sulfonamides and PHOS could have good synergistic effects against multi-drug-resistant gram-negative bacilli. Monitoring the in vitro combined efficacy before treatment would improve the accuracy of antibiotic use and is of great clinical value.

Colonization and risk of infection by multidrug-resistant bacteria in hemodialysis patients: a topic of concern / Colonización e infección por bacterias multirresistentes en pacientes en hemodiálisis: un tema de preocupación

Antimicrobial resistance worsens the prognosis in patients with chronic diseases. Patients on hemodialysis have infection rates that exceed those reported in other types of patients. Colonization has been suggested as a risk factor for the development of infections. However, the majority of the studies that have evaluated this association have methodological limitations that have called into question the validity of the results; such as the lack of use of molecular methods to confirm that the colonizing species are the same as that which causes infection, the measurement of exposure only at the beginning of the study, the absence of follow-up, the evaluation of bacteremia as the only important outcome and the focus only on Staphylococcus aureus, without including other resistant bacteria of clinical importance such as multidrug-resistant Gram-negative bacteria. This lead to the need to use molecular epidemiology methods for refine the association between colonization and infection in endemic countries like Colombia, where the high rates of antimicrobial resistance demand accurate prevention strategies in susceptible patients.

La resistencia antimicrobiana empeora el pronóstico en pacientes con enfermedades crónicas. Los pacientes en hemodiálisis son un grupo particularmente afectado con porcentajes de infección bacteriana que exceden las reportadas en otro tipo de pacientes. La colonización ha sido sugerida como un factor de riesgo para el desarrollo de infecciones. Sin embargo, los estudios que han evaluado esta asociación presentan limitaciones metodológicas que han cuestionado la validez de los resultados; como la falta de utilización de métodos moleculares que confirmen que la especie que coloniza es la misma que causa infección, la medición de la exposición solo al inicio del estudio, la ausencia de seguimiento y la evaluación de bacteriemia como el único desenlace de importancia. Así mismo, la mayoría de los estudios se han enfocado solo en Staphylococcus aureus sin incluir otras bacterias resistentes de importancia clínica como son los bacilos Gram negativos multirresistentes. Lo anterior lleva a la necesidad de utilizar métodos de epidemiología molecular que permitan refinar el análisis de la asociación entre colonización e infección, más aún en países endémicos como Colombia, en el que los altos porcentajes de resistencia demandan estrategias de prevención más certeras en pacientes susceptibles.

Endocarditis infecciosa por bacilos gram negativos no HACEK. Experiencia en un centro de alta complejidad de la República Argentina (1998-2016) / Infective endocarditis due to non-HACEK gram-negative bacilli in a Level III cardiovascular center in Argentina (1998-2016)

Los bacilos gram negativos (BGN) que no pertenecen al grupo HACEK son una causa infrecuente de endocarditis infecciosa. Los aspectos epidemiológicos, diagnósticos y pronósticos de esta entidad son poco conocidos y la experiencia aún es limitada. Nuestros objetivos fueron analizar las características clínicas y microbiológicas de las endocarditis infecciosas (EI) por BGN no HACEK diagnosticadas en un centro de alta complejidad de Argentina en el período 1998-2016 y conocer su evolución hospitalaria, a fin de compararlas con las EI debidas a otros microorganismos.

Non-HACEK Gram-negative bacilli are a rare cause of infective endocarditis. Epidemiological, diagnostic and prognostic aspects of this entity are little known, and there is limited experience. The aim of this study was to analyze the clinical, microbiological and in-hospital outcomes of non-HACEK Gram negative bacilli endocarditis and to compare them with those due to other microorganisms.

Prevalence of Non Fermenting Gram Negative Bacilli with Their in vitro Antibiotic Sensitivity Profile in RIMS, Ranchi

Background: Non fermenting Gram Negative Bacilli arediverse and complex group of bacteria that possess very fewdefined characteristics. They are aerobic, non-fermentingGram negative bacilli which were initially considered ascontaminants but have come up with life threatening infectionsin hospitals as multidrug resistant organisms posing a threatbecause of their inherent and acquired drug resistance nature.Aims: Isolation and identification of NFGNB in clinical samplesand determination of their antibiotic sensitivity profile.Materials and Methods: The study was conducted in theDepartment of Microbiology, RIMS, Ranchi from February2017-July 2017. Various clinical samples reaching theBacteriology section of the Department of Microbiology wereprocessed and NFGNB were isolated and identified usingstandard procedure and their antibiotic susceptibility wasperformed.Results: A total of 3581 samples were received out of which2246 were culture positive and 217 were identified as NFGNB.The isolation rate of NFGNB was 9.6%. Number of malesaffected by NFGNB was 121 and that of females was 96.Analysed by specimen NFGNB were isolated from 91 urine, 74pus, 11 ear swab, 6 sputum, 8 body fluid, 21 blood culture and6 catheter tip samples. Urine was most common specimenaccounting for 42% followed by pus (34%), blood (9%), earswab (5%), body fluid (4%), sputum and catheter tip (3%each).The clinical samples from indoor patients yielded highestpercentage of NFGNB (38%) followed by ICU patients (36%)and outdoor patients (26%). Among the NFGNB isolatedPseudomonaas aeruginosa (51%) was the most commonfollowed by Acinetobacter baumanii (22%), Pseudomonas spp(19%), Acinetobacter spp, Stenotrophomonas maltophila,Burkholderia cepacia (2% each), Ralstonia spp &Sphingobacterium spp (1%). Non fermenters were highlysensitive to Imipenem accounting for 91.5% followed byPiperacillin-tazobactam (71.5%), cefoperazone sulbactam(67.7%) & Amikacin (55.6%) on an average.Conclusion: NFGNB considered being contaminants in thepast have now emerged as important health care associatedinfections. In our setting Imipenem can be used for thepreliminary treatment of infections caused by nonfermenters.As these organisms are important opportunistic andnosocomial pathogens causing infections inimmunocompromised patients, better infection control policiesin our settings and its implementation is a must.

Multidrug resistant, extensively drug resistant and pan drug resistant gram negative bacteria at a tertiary care centre in Bhubaneswar

Background: Multidrug resistance has emerged as a challenge in health care settings. Again increasing prevalence of multidrug resistant (MDR), extensively drug resistant (XDR) and pan drug resistant (PDR) gram negative bacteria is making the condition more critical because of limited options of antibiotics, increasing morbidity, mortality and hospital stay of the patients. The present study is carried out with an aim to estimate the prevalence of MDR, XDR, PDR gram negative bacteria in a tertiary care hospital.Methods: Total of 912 gram negative bacterial isolates obtained from various samples of indoor patients in a tertiary care hospital, were studied over a period of six months. The bacteria were identified by conventional methods. Antibiotic sensitivity testing was done by Kirby Bauer disc diffusion method. Minimum inhibitory concentration (MIC) of antibiotics for the resistant isolates were detected by Vitek-2 automated method. MDR, XDR and PDR were determined according to the definitions suggested by European Centre for Disease Prevention and Control (ECDC), and Centers for Disease Control and Prevention (CDC). Prevalence of extended spectrum beta lactamase (ESBL) producers was estimated.Results: Out of 912 isolates, prevalence of MDR, XDR and PDR were 66.12%, 34.32% and 0.98% respectively. Prevalence of MDR and XDR were higher in ICUs than clinical wards (p<0.0001). Prevalence of ESBL producers was 48.4%.Conclusions: The study highlights increased prevalence of multidrug resistant and extensively drug resistant strains in our hospital. Stringent surveillance, proper implementation of hospital infection control practices and antimicrobial stewardship will help in limiting the emergence and spread of drug resistant strains.

Identification of bacterial urinary tract pathogens from urine samples using conventional methods and matrix-assisted laser desorption ionization-time of flight mass spectrometry

Background: Early diagnosis of urinary tract infections (UTIs) is essential to avoid inadequate or unnecessary empirical antibiotic therapy. In this study, we evaluate the coincidence rate between conventional method for the diagnosis of UTIs (plate cultures and identification based on biochemical characteristics) and a fast method based on Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS). In recent years, proteomic techniques have achieved a relevant role in the identification of microorganisms in the field of clinical microbiology. MALDI-TOF MS has been suggested as a fast and reliable method for bacterial identification.Methods: Around 50 midstream urine samples submitted to Microbiology laboratory for Gram staining and bacterial culture were analyzed. Samples were microscopically tested, characterized, and identified using different media such as blood agar and Mac Conkey agar and by applying suitable biochemical tests. Urine specimens showing a significant bacteriuria on culture and single morphological type by Gram staining were then processed by MALDI-TOF MS.Results: Of 50 specimens, colony growth was observed in 43(86%) specimens, and 38(88.3%) specimens had growth of single-colony morphological type in culture. 32(84.2%) of them had colony counts of >105 colony forming units (CFUs)/ml. 7(14%) samples were negative in culture, and all of them were also negative by MALDI-TOF MS. Microorganism identifications in this group were coincident at the species level in 28(87.5%) specimens. The most frequent microorganism identified was Escherichia coli, followed by Klebsiella species and Acinetobacter baumanii. MALDI-TOF MS identified Providencia stuartii in 3 samples and Pseudomonas putida in 1 of them; which were not in accordance with the conventional method used for identification.Conclusions: Present study results show that MALDI-TOF MS allows bacterial identification from infected urine in a short time, with high accuracy, and especially when uncommon uropathogens are involved.

Avaliação da multirresistência a antibióticos e produção de ESBL e carbapenemases em bacilos gram-negativos de efluente hospitalar e urbano / Evaluation of antibiotic multi-resistance and production of ESBL and carbapenemases in gram-negative bacilli of hospital and urban effluent

A multirresistência aos antibióticos observada em bacilos gram-negativos é um grave problema de saúde pública devido a alta morbidade e mortalidade apresentada, especialmente em instituições assistenciais de saúde. Como consequência do intenso uso de antibióticos, a multirresistência a esses fármacos é principalmente mediada por enzimas hidrolisantes, onde destaca-se as enzimas ?-lactamases, principal mecanismo de resistência aos ?-lactâmicos verificado em bacilos gram-negativos. Os esgotos de origem hospitalar e de estações de tratamento de esgoto (ETE) são considerados como reservatórios de bactérias multirresistentes pela presença de antibióticos que as selecionam e por favorecem a transmissão de determinantes de resistência. Nesse sentido, o presente estudo objetivou avaliar a multirresistência a antibióticos e a produção de enzimas ?-lactamases em bacilos gram-negativos isolados de efluente hospitalar e da estação de tratamento de esgoto, na cidade de Ribeirão Preto, SP. No hospital terciário, amostras de esgotos foram coletadas dos ambulatórios, das enfermarias e da junção do esgoto hospitalar. Na ETE, amostras foram coletadas na caixa de entrada do esgoto bruto e após ao tratamento. Dez microlitros foram semeados em ágar MacConkey, SalmonellaShigella, Cetrimide e TCBS e a identificação dos bacilos gram-negativos foi realizada pelo kit Bactray®. O teste de susceptibilidade aos antibióticos foi realizado pelo método de discodifusão em ágar. A detecção fenotípica de bacilos produtores de ESBL foi realizada pelos testes de sinergia de disco-duplo e disco combinado com ácido clavulânico, e para detecção de isolados produtores de carbapenemases foi utilizado os testes de disco combinado com ácido fenilborônico e EDTA e o teste Blue Carba. A PCR foi utilizada para amplificação dos genes codificadores de ESBL e carbapenemases. No total, 45 bacilos gram-negativos foram isolados, sendo as espécies Klebsiella pneumoniae e Pseudomonas aeruginosa as de maiores prevalências. Ampla resistência foi verificada aos antibióticos ?-lactâmicos, sendo a resistência ao aztreonam, a cefepime e a cefotaxima mais expressiva nos isolados do esgoto hospitalar, com diferenças estatisticamente significante (p<0,05). O fenótipo multidroga resistente foi atribuído a 33,3%, nos isolados exclusivamente do esgoto hospitalar, com diferença estatisticamente significante (p = 0,0025) em relação aos isolados do esgoto da ETE. Genes de ?-lactamases foram encontrados em 35,6% das bactérias, sendo o blaKPC e blaTEM os de maiores ocorrências, ambos em 17,8% dos isolados, e os genes blaSHV e blaCTX-M em 13,3% e 8,9%. Somente em um isolado de Enterobacter cloacae no esgoto tratado da ETE foi identificado o gene blaSHV, os demais isolados portadores dos genes de ?-lactamases foram encontrados no esgoto hospitalar. Os dados obtidos neste estudo são importantes levando em consideração que no Brasil o esgoto hospitalar pode ser lançado in natura na rede coletora municipal, no entanto, acredita-se que tal permissão favorece a disseminação da multirresistência bacteriana, posto que, os resultados demonstram alta frequência de bactérias portadoras de genes de resistência a antibióticos no esgoto hospitalar estudado. Assim, a implementação do tratamento de efluentes hospitalares, especialmente os de hospitais terciários, e adicionalmente ao tratamento da ETE evitaria a propagação dessas bactérias no ambiente e de impactar negativamente os recursos hídricos

Antibiotic multi-resistance observed in Gram-negative bacilli is a serious public health problem due to high morbidity and mortality, especially in health care institutions. As a consequence of the intense use of antibiotics, multi-resistance to these drugs is mainly mediated by hydrolyzing enzymes, in which ?-lactamases, the main ?-lactam resistance mechanism observed in Gramnegative bacilli, are prominent. Hospital sewage and wastewater treatment plants (WWTP) are considered reservoirs of multiresistant bacteria by the presence of antibiotics that select these bacteria and favor the transmission of resistance determinants. In this sense, the present study aimed to evaluate the antibiotics multi-resistance and the production of ?-lactamase enzymes in Gram-negative bacilli isolated from hospital effluent and the wastewater treatment plants in Ribeirão Preto city, SP. In the tertiary hospital, sewage samples from the outpatient clinics, rooms patients and the hospital sewage junction were collected. In the WWTP, raw and treated sewage were collected. Ten microliters were seeded on MacConkey, Salmonella-Shigella, Cetrimide and TCBS agar and the identification of Gram-negative bacilli was performed by the Bactray® kit. Antibiotic susceptibility test was performed by agar-diffusion method. Phenotypic detection of ESBL-producing bacilli was performed by double-disc and discsynergy tests combined with clavulanic acid, and for the detection of carbapenemase-producing isolates the combined disk tests with phenylboronic acid and EDTA and Blue Carba test were used. PCR amplification of ESBL and carbapenemases-encoding genes was used. In total, 45 Gram-negative bacilli were isolated, and Klebsiella pneumoniae and Pseudomonas aeruginosa being the most prevalent. Extensive resistance was verified to ?-lactam antibiotics and resistance to aztreonam, cefepime and cefotaxime was more pronounced in hospital sewage isolates, with statistically significant differences (p<0.05). Multidrug-resistant phenotype was attributed to 33.3% in isolates exclusively from hospital sewage, with a statistically significant difference (p = 0.0025) in relation to the sewage isolates from the WWTP. ?-lactamase genes were found in 35.6% of the bacteria, with blaKPC and blaTEM having the highest occurrences, both in 17.8% of the isolates, and the blaSHV and blaCTX-M genes in 13.3% and 8, 9%. Only in an isolate of Enterobacter cloacae in the treated sewage from WWTP was the blaSHV gene identified, the other isolates carrying the ?-lactamases genes were found in hospital sewage. The data obtained in this study are important considering that in Brazil the hospital sewage can be released in nature in municipal collection network, however, it is believed that such permission favors the dissemination of bacterial multi-resistance, since, the results show high frequency of bacteria carrying antibiotic resistance genes in the hospital sewer studied. Thus, the implementation of treatment of hospital effluents, especially those in tertiary hospitals, and in addition to the treatment of WWTP would prevent the spread of these bacteria in the environment and negatively impact water resources

Evaluation of a Carbapenem-Saving Strategy Using Empirical Combination Regimen of Piperacillin-Tazobactam and Amikacin in Hemato-Oncology Patients

We implemented a carbapenem-saving strategy in hemato-oncology patients from 2013, using an empirical combination of piperacillin-tazobactam and amikacin for high-risk hemato-oncology patients with febrile neutropenia, who remain hemodynamically unstable > 72 hours despite initial cefepime treatment. All-cause mortality was not different between the two periods (6.54 and 6.57 deaths per 1,000 person-day, P = 0.926). Group 2 carbapenem use significantly decreased after strategy implementation (78.43 vs. 67.43 monthly days of therapy, P = 0.018), while carbapenem-resistant gram-negative bacilli did not show meaningful changes during the study period. Our carbapenem-saving strategy could effectively suppress carbapenem use without an increase of overall mortality.