Antimicrobial Resistance, Phenotypic Characteristics, and Biofilm Production in Citrobacter freundii Isolates Obtained from Urinary Tract Infections

Objective To evaluate the link between phenotypic traits, antimicrobial resistance, and biofilm-producing capacity of urinary isolates of Citrobacter freundii (C. Freundii). Methods Both pan-antibiotic-susceptible and -resistant C. freundii isolates (n = 120) obtained from laboratory-confirmed urinary tract infections were analyzed for their link between antimicrobial resistance, phenotypic characteristics, and biofilm production. Results Of the total C. freundii isolates (n = 120), 30% (37/120) of them formed large colonies. Among the total large colonies produced (n = 37), they were present in 21.62%, 10.81%, 13.5%, 16.2%, 21.62%, and 16.21% in the control group, CIP-group, FOS-group, COT-group, Gent-group, and ESBL groups, respectively. Compared to the pan-susceptible isolates, the occurrence of large-sized-colony-forming strains was relatively reduced in most of the drug-resistant groups. The overall distribution of mucoid colonies produced (n = 54) includes 9.25%, 18.51%, 16.66%, 18.51%, 20.3%, and 16.66% in the control group, CIP-group, FOS-group, COT-group, Gent-group, and ESBL groups, respectively. Of the total isolates that produced biofilm (n = 51), 11.76% of isolates showed biofilm formation in the control group. Alternatively, the rate was found to be 15.68%, 11.76%, 25.49%, 19.6%, and 15.68% in the CIP-group, FOS-group, SXT-group, Gen-group, and ESBL-groups, respectively. Conclusion This study correlates the association between phenotypic characteristics, antimicrobial resistance, and biofilm production, the three main characteristics of C. Freundii.

Etiologic identification and drug susceptibility analysis of a Citrobacter freundii food poisoning event / 中国热带医学

@#Abstract: Objective　In order to provide reference for emergency treatment of a sudden food poisoning incident, pathogen detection and drug resistance analysis were carried out. Methods　Diarrheal stool and surplus food samples were detected by GB 4789 and the isolates were identified by VITEK2 and matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), at the same time, the bacterial drug sensitivity test was carried out by using the method of microbroth dilution, and the isolates from different sources were molecularly classified by pulsed field gel electrophoresis (PFGE), and the correlation between the strains was analyzed by BioNumerics software. Results　Totaly 13 leftovers and 3 diarrhea patients were isolated and identified, The total number of colonies and coliforms in 7 leftovers samples all exceeded the standard, and Citrobacter freundii was detected in 5 leftovers and 2 stools. The results of drug sensitivity test showed that seven strains of Citrobacter freundii were sensitive to ciprofloxacin, tetracycline, chloramphenicol, gentamicin, amikacin, cefotaxime and meropenem, but completely resistant to ampicillin, and there was no multiple drug resistance. The results of pulsed field gel electrophoresis (PFGE) showed that 7 strains of Citrobacter freundii had the same PFGE bands and 100% homology, showing the same clone. Conclusions　This food poisoning incident was caused by Citrobacter freundii. The pathogen of food poisoning can be quickly and accurately determined by MALDI-TOF MS, which is beneficial to the early diagnosis and treatment of infectious diseases. It is suggested to strengthen the corresponding management, improve food safety awareness and prevent similar incidents.

Bio prospecting of Riboflavin producing bacteria from different riboflavin enriched food sources

Riboflavin is an essential, water-soluble vitamin (B2) and a component of basic cellular metabolism. The aim of the present study is to isolate and characterize riboflavin producing bacteria from different food sources. Ten different riboflavin enriched food sources were collected from Vellore district. Totally 72 bacterial strains were isolated and cultured on nutrient agar plates. Out of these, 43 strains were identified as riboflavin producers. Isolated bacterial strains HDS27, HDS07, HDS14, HDS18, HDS38 and HDS54 isolated from milk, mushroom, spinach, lamb kidney, beef liver and mackerel fish were found to be potent riboflavin producers. Based on morphological, biochemical and molecular characterization, the potent strains were identified as Lactobacillus plantarum (HDS27), Bacillus cereus (HDS07), Delftia tsuruhatensis (HDS14), Citrobacter freundii (HDS18), Enterobacter cloacae (HDS38) and Bacillus cereus (HDS54). The selected potent isolates HDS27 from milk and HDS07 from mushroom showed a maximum riboflavin production of 3.69 mg/L and 2.9mg/L respectively. The present study explores the riboflavin producing novel bacteria from different food sources. This is the first report that the Enterobacter cloacae isolated from beef liver, Delftia tsuruhatensis from spinach and Citrobacter freundii from lamb kidney has the ability to produce riboflavin. These potent strains could be a better starter for substituting the conventional bacteria for large scale production of riboflavin in industry.

Citrobacter freundii multirresistente como agente etiológico de infección de vías urinarias / Multiresistant Citrobacter freundii as an etiological agent of urinary tract infection

Citrobacter freundii, en ocasiones puede actuar como patógeno oportunista, se presenta un caso de este microorganismo aislado como agente etiológico de infección del tracto urinario, en un paciente con enfermedad pulmonar obstructiva crónica. El aislado fue multirresistente, mostrando resistencia a gentamicina, amikacina, trimetoprim sulfametoxazole, ciprofloxacino, ceftriaxona, ceftazidima, cefepime, imipenem, meropenem y doripenem y, susceptibilidad a tigeciclina y colistina, el estudio molecular demostró la presencia del gen blaKPC.

Citrobacter freundii, sometimes it can act as opportunistic pathogen, a case of this isolated microorganism is presented as an etiological agent of urinary tract infection, in a patient with chronic obstructive pulmonary disease. The isolate was multiresistant to gentamicin, amikacin, trimetoprim sulfamethoxazole, ciprofloxacin, ceftriaxone, ceftazidime, cefepime, imipenem, meropenem and doripenem and it was susceptible to tigecycline and colistin, the molecular analysis showed the presence of the blaKPC gene.

Primer aislamiento de enterobacteria productora de carbapenemasa tipo-NDM en un hospital público de Rosario, Argentina PDF / First isolation of a NDM-like carbapenemase-producing Enterobacteriaceae in a public hospital in Rosario, Argentina

Introducción: La emergencia de enterobacterias productoras de carbapenemasas en el ámbito hospitalario representa un verdadero problema de salud pública mundial. Las carbapenemasas son enzimas que producen resistencia a los antibióticos carbapenémicos, teniendo un directo impacto en la disponibilidad de alternativas terapéuticas. En Argentina, a partir de 2013 han emergido carbapenemasas tipo-NDM (Nueva Delhi Metalo-ß-lactamasa, MßL), que constituyen una resistencia emergente a nivel global. Objetivo: Reportar el primer aislamiento clínico de enterobacteria portadora de NDM en nuestra institución. Materiales y métodos: El aislamiento estudiado fue recuperado de una muestra ósea de un paciente adulto. La identificación bacteriana y los ensayos de susceptibilidad antibiótica se realizaron mediante metodología manual y sistema automatizado Vitek 2C (Biomérieux). La detección y caracterización de carbapenemasas se efectuó por ensayos fenotípicos y moleculares. Resultados: Los ensayos revelaron que el aislamiento, tipificado como Citrobacter freundii, es productor de carbapenemasa tipo NDM. Resultó sensible a aztreonam, colistina y fosfomicina. No se detectó fenotípicamente la presencia de beta lactamasas de espectro extendido. Discusión: Se reporta el primer aislamiento de enterobacteria productor de MßL tipo-NDM en nuestro nosocomio, siendo multirresistente, con escasas alternativas terapéuticas. Dado que la presencia de este tipo de aislamiento es considerado de alto riesgo, se requiere un monitoreo activo de este mecanismo de resistencia y la instauración de medidas de control adecuadas para hacer frente a la amenaza que suponen

Introduction: the emergence of carbapenemase-producing Enterobaceriaceae in the hospital environment represents a major challenge for health care worldwide. Carbapene-mases are carbapenem-hydrolysing enzymes that confer resistance to these "last-line" antibiotics having a direct im-pact on the limited treatment options available. In Argentina, carbapenemases NDM-like (New DelhiMetallo-ß-lactamase, MßL) have emerged in 2013. This resistance has increased in frequency and it has disseminated around the world at unprecedented levels.Objective:report the first isolation of a NDM-producing En-terobacteriaceae in our hospital.Materials and methods: the isolate analysed in this study was recovered from a bone biopsy belonging to an adult patient. The bacterial identification and antimicrobial sus-ceptibility testings were performed using conventional methods and the automated system Vitek 2C (Biomérieux). Phenotypic and molecular techniques were carried out for the detection and characterization of carbapenemases.Results: it was confirmed that the isolate, identified as Citro-bacter freundii, produces the NDM enzyme. It showed sensi-bility to aztreonam, colistin and fosfomicyn. Extended-spec-trum beta-lactamases were not detected.Discussion: in this study we report the first isolation of NDM-like MßL in our institution, a multirresistant pathogen associ-ated with a lack of effective antimicrobial treatment options. Given the high risk of these infections, an active search of mechanisms of resistance is mandatory. In addition, the establishment of accurate control measures is a must to attempt to overcome this formidable threat

Empyema necessitatis due to Citrobacter freundii: Case report / Empiema necessitatis por Citrobacter freundii. Reporte de caso

Abstract Introduction: This paper presents the first case of empyema necessitatis secondary to infection with Citrobacter freundii (according to the databases consulted), and one of the few reports of this pathology in Colombia. Case presentation: This is the case of a 26-year-old patient from a rural area, with a history of severe cognitive deficit, who was taken to the emergency department due to a clinical picture of 15 days of evolution consisting of neurological deterioration associated with asthenia, adynamia, fever and cough with purulent expectoration. On admission, a chest x-ray was taken, finding pneumonia of the middle lobe with associated pleural effusion, for which empirical antibiotic management was initiated. The patient presented clinical deterioration and appearance of right pectoral mass, so a computed tomography of the thorax was performed, revealing empyema necessitatis. Close drainage and culture of the collection were made, with negative mycobacteria culture and positive report for C. freundii. The patient received specific antibiotic treatment for 8 weeks, with complete improvement of his clinical condition. Conclusion: Besides being the first case of empyema necessitatis by C. freundii that has been reported, this case is important because of the low amount of reports on this pathology in Colombia, considering that its main cause is tuberculosis, which is endemic in the country.

Resumen Introducción. Según lo encontrado en las bases de datos consultadas, el presente es el primer caso de empiema necessitatis secundario a Citrobacter freundii. Además, constituye uno de los pocos reportes de esta patología en Colombia. Presentación del caso. Se trata de un paciente de 26 años procedente de área rural, con antecedente de déficit cognitivo severo, quien fue llevado al servicio de urgencias por cuadro clínico de 15 días de evolución consistente en deterioro neurológico asociado a astenia, adinamia, fiebre y tos con expectoración purulenta. Al ingreso se tomó radiografía de tórax, encontrando neumonía del lóbulo medio con derrame pleural asociado, por lo que se inició cubrimiento antibiótico empírico. El paciente presentó deterioro clínico y aparición de masa pectoral derecha, por lo que se realizó tomografía computarizada de tórax, evidenciando empiema necessitatis. Luego, se hizo drenaje de la colección, con cultivo negativo para micobacterias y aislamiento de C. freundii. Se dio tratamiento guiado por antibiograma durante ocho semanas, con posterior recuperación completa del cuadro clínico. Conclusión. Además de ser el primer caso de empiema necessitatis por C. freundii, este es importante por la escasa cantidad de reportes en Colombia, considerando que su principal causa es la tuberculosis, la cual es endémica en el país.

Study on plasmid-mediated blaNDM-1 gene in carbapenem-resistant Citrobacter freundii / 中国感染与化疗杂志

Objective To investigate the transmission of blaNDM-1 gene in carbapenem-resistant Citrobacter freundii. Methods A total of 18 strains of NDM-1-producing C. freundii were collected from the First Affiliated Hospital of Kunming Medical University during the period from June 2012 to October 2014. The isolates were identified and subjected to antimicrobial susceptibility testing with VITEK 2 System. Conjugation experiments, pulsed-field gel electrophoresis (PFGE) and Southern blot hybridization were performed to determine the transferability of plasmids. Results The antibiotic susceptibility results showed that all the NDM-1-producing C. freundii isolates were resistant to penicillins, cephalosporins and carbapenems. All isolates exhibited different level resistance to other antibiotics. Conjugation experiments revealed that the plasmids harboring blaNDM-1 in 13 strains were transformed into E. coli 600, and exhibited carbapenem resistance. PFGE and Southern blot hybridization found that blaNDM-1 was located on a 33.3 kb plasmid in 16 isolates and on 33.3-54.7 kb plasmid in 2 isolates. Conclusions Our findings suggest that plasmids contribute to the horizontal dissemination of blaNDM-1 gene in carbapenemresistant C. freundii.

Sudden Deaths of Neonates Receiving Intravenous Infusion of Lipid Emulsion Contaminated with Citrobacter freundii

At an intensive care unit, four neonates died consecutively within 80 minutes. Citrobacter freundii was isolated from blood samples of the 4 patients. It was also cultured from the leftover SMOFlipid that had been infused intravenously into the patients. In this in vitro study, we evaluated the bacterial growth kinetics and change in size of fat globules in SMOFlipid contaminated with C. freundii. Following the growth of bacteria, pH of SMOFlipid decreased to < 6, and the number of fat globules larger than 5 µm increased. Pulmonary fat embolism is proposed as a possible cause of the sudden deaths as well as fulminant sepsis.

Estudo genotípico e fenotípico de bacilos Gram-negativos produtores de carbapenemase do tipo New Delhi metalo-ß-lactamase / Genotypic and fenotypic study of Gram-negative bacilli producers carbapenemase type New Delhi metallo--ß-lactamase

Os carbapenêmicos são os antimicrobianos mais amplamente utilizados no tratamento empírico de infecções graves por bacilos Gram-negativos. A pressão seletiva gerada pelo uso desses antimicrobianos ao longo das últimas três décadas contribuiu para a disseminação de enterobactérias e Gram-negativos não fermentadores produtores de carbapenemases, particularmente as do tipo KPC e NDM. Os genes que codificam essas enzimas usualmente estão localizados em plasmídeos e/ou transpósons. A hipótese atualmente mais aceita é que o gene blaNDM-1 seja uma quimera criada em Acinetobacter baumannii. A NDM-1 foi descrita em paciente proveniente da Índia e subsequentemente evidenciou-se sua ampla disseminação nesse país. A epidemiologia que tem sido observada nos casos detectados na Europa e Estados Unidos tem sido viagem à Índia, ou seja, sem casos autóctones. No Brasil, os primeiros casos foram identificados no Rio Grande do Sul, e a seguir no Rio de Janeiro e em São Paulo. Diferentemente dos casos da Europa e América do Norte, os casos do Brasil não tem relação epidemiológica com a Índia. O sequenciamento integral dos plasmídeos e cromossomos albergando o gene blaNDM permitirá entender como ocorre a disseminação desse mecanismo de resistência no Brasil. Para isso, foi avaliado o perfil de susceptibilidade dos isolados, bem como a capacidade conjugativa e clonalidade. Das vinte e oito amostras utilizadas neste trabalho, treze delas pertencem à espécie Enterobacter hormaechei, uma à espécie Citrobacter freundii, sete à espécie Escherichia coli, quatro à Klebsiella pneumoniae e três ao gênero Acinetobacter spp. Os primeiros isolados incluídos neste estudo (Escherichia coli e Enterobacter hormaechei produzindo NDM-1) foram isolados em agosto de 2013, de uma mesma amostra de swab retal de um paciente do Rio de Janeiro que nunca viajou para o exterior. O sequenciamento completo do DNA plasmidial utilizando a plataforma Illumina e a anotação de ambos os plasmídeos albergando o gene blaNDM-1 revelou que estes pertencem a grupos de incompatibilidade diferentes, IncFIIK (E. hormaechei) e IncX3 (E. coli), e abrigam um novo transpóson composto designado Tn3000. A comparação da sequência nucleotídica do Tn3000 com aquelas disponíveis no GenBank evidencia que a mesma estrutura está presente em plasmídeos de isolados da cidade de Porto Alegre e também em diferentes continentes. As espécies de Acinetobacter (A. radioresistens, A. ursingii e A. guillouiae) isoladas em São Paulo e Porto Alegre, possuem o gene blaNDM-1 albergados em um mesmo plasmídeo não tipável de 41.087 pb. A avaliação da clonalidade dos isolados de Enterobacter hormaechei "subsp. oharae" mostrou dois perfis diferentes através da técnica de PFGE, sendo que todos os microrganismos foram isolados de um surto no mesmo hospital no Rio de Janeiro. Isolados de Klebsiella pneumoniae de uma mesma paciente internada em hospital em Salvador, de sítios distintos - swab retal, hemocultura e urina, em ordem cronológica - obtiveram o mesmo perfil clonal pela técnica de PFGE. O mesmo ocorreu com três isolados de Escherichia coli, de um mesmo paciente do Rio de Janeiro, em amostras de swab retal. Os achados deste estudo evidenciam que no Brasil, Nepal, Marrocos e Índia há uma disseminação do gene blaNDM-1 mediada por um novo elemento móvel designado Tn3000 em enterobactérias. A detecção de um mesmo plasmídeo em diferentes espécies de Acinetobacter evidencia que neste gênero bacteriano, no Brasil, a disseminação do gene blaNDM-1 ocorre por conjugação.

Carbapenems are the antimicrobials most widely used in the empirical treatment of severe infections caused by Gram-negative bacilli. The selective pressure generated by the use of these antibiotics over the last three decades has contributed to the spread of enterobacteria and Gram-negative non-fermenting producing carbapenemases, mainly KPC and NDM. Genes encoding these enzymes are usually located in plasmids and/or transposons. Currently the most accepted hypothesis is that the blaNDM-1 gene is a chimera created in Acinetobacter baumannii. The NDM-1 was described in a patient from India and subsequently was reported to be broadly disseminate in this country. The epidemiology that has been observed in cases detected in Europe and United States is traveling to India, but no autochthonous cases. In Brazil, the first cases were identified in Rio Grande do Sul, and then in Rio de Janeiro and São Paulo. Differently from the cases described in Europe and North America, the cases from Brazil have no epidemiological link with India. The complete sequencing of plasmids and chromosomes harboring blaNDM gene will understanding how the dissemination of this resistance mechanism in Brazil occurs. In this work we will be evaluate the susceptibility profile of the isolates, and their conjugal capacity and clonality. Of the twenty-eight samples used in this study, thirteen of them belong to the species Enterobacter hormaechei, one to Citrobacter freundii, seven to Escherichia coli, four to Klebsiella pneumoniae and three to the genus Acinetobacter sp. The first two isolates included in this study (Escherichia coli and Enterobacter hormaechei) were isolated in August 2013, from the same rectal swab sample from a patient from Rio de Janeiro that never traveled abroad. Complete sequencing of plasmid DNA using Illumina platform and annotation of both plasmids harboring the blaNDM-1 gene revealed that they belong to different incompatibility groups, IncFIIK (E. hormaechei) and IncX3 (E. coli), and are harbor to a new transposon designated Tn3000. The comparison of the Tn3000 nucleotide sequence with those available at GenBank shows that the same structure is present in plasmids from other Porto Alegre and also in different continents. The Acinetobacter species (A. radioresistens, A. ursingii and A. guillouiae) isolated in São Paulo and Porto Alegre, have the blaNDM-1 gene harbored in a single non-typing plasmid of 41,087 bp. The evaluation of clonal relationship of Enterobacter hormaechei "subsp. oharae" showed two different profiles by PFGE technique; of note all microorganisms were isolated from an outbreak in the same hospital in Rio de Janeiro. Isolates of Klebsiella pneumoniae from a single patient hospitalized in Salvador, from different anatomical sites - rectal swab, blood culture and urine, in chronological order - obtained the same clonal profile by the PFGE technique. The same occurred with three Escherichia coli isolates, from the same patient from Rio de Janeiro, in swab rectal strains. Our findings suggest that in Brazil, Nepal, Morocco and India there is a spread of blaNDM-1 gene mediated by Tn3000 in enterobacteria. The detection of a same plasmid in different species of Acinetobacter shows that in this bacterial genus, in Brazil, the dissemination of the blaNDM-1 gene occurs by conjugation.

Cristaluria masiva asociada a infección urinaria ureolítica: un caso exepcional / Massive crystalluria associated whit ureolitic urynary infection: an exceptional

Introducción y Objetivos. Las infecciones urinarias por gérmenes ureolíticos se asocian generalmente con la eliminación y/o formación de cálculos infectivos de estruvita (fosfato amónico magnésico, fosfato triple). Sin embargo no tenemos conocimiento de que se haya comunicado ningún caso de emisión masiva de cristales con visualización macroscópica y recuperación de las arenillas en el "poso seco" del sedimento de la orina. El objetivo de este breve artículo es comunicar un infrecuente caso de cristaluria masiva de fosfato amónico magnésico secundaria a infección urinaria por la asociación de dos gérmenes: Citrobacter freundii (no ureolítico) y Morganella morgagnii (ureolítica). Caso Clínico. Mujer de 72 años sin antecedentes urológicos previos que consultó por presentar desde hace 1 año expulsión de gran cantidad de arenillas en las micciones, hasta el punto de que en alguna ocasión le ocluían momentáneamente la uretra. La paciente aportó una muestra de la cristaluria (arenilla) recuperada del poso seco del sedimento de su orina, donde se aprecia un gran volumen de polvo y arena (microcristales). El estudio del sedimento urinario mostró PH 8, densidad de 1035 (n 1005-1030), nitritos (+), bacteriuria y abundante cantidad de cristales incoloros en forma de prisma o "ataúd" sugestivos de corresponder a cristales de fosfato amónico magnésico. En el urinocultivo existían 500.000 UFC/ml y se aislaron 2 gérmenes uno no ureolítico (Citrobacter freundii) y otro ureolítico (Morganella morgagnii). Radiografía simple de aparato urinario y ecografía normales. El análisis químico de la arenilla mostró una composición de 80 por ciento fosfato amónico magnésico y 20 por ciento oxalato cálcico. Se instauró tratamiento según antibiograma con ciprofloxacino 500 mg cada 12 horas 7 días y se acidificó la orina con vitamina C (ácido ascórbico) 500 mg día 20 días, consiguiendo erradicar la infección urinaria, normalizar el PH urinario a 5, y frenar definitivamente la expulsión de cristales. En un control a los 6 meses permanecía asintomática y con urinocultivo estéril. Conclusiónes. Este caso es una forma de presentación excepcional de una infección urinaria ureolítica, sin los síntomas clásicos habituales. Su única manifestación clínica fue la expulsión de gran cantidad de cristales (arenilla) en las micciones que en ocasiones provocaban obstrucciones intermitentes de uretra de resolución espontánea. Este singular caso demuestra que escuchando a los pacientes, a veces nos cuentan hechos casi imposibles y la mayoría de las veces son verídicos (AU)

Background and Objetives. Ureolytic urinary tract infections are generally associated with the elimination and / or formation of struvite infective stones (magnesium ammonium phosphate, triple phosphate). However, we are not aware of any reports of massive emission of crystals with macroscopic visualization and recovery of the sand in the "dry" sediment of the urine. The objective of this brief article is to report an infrequent case of massive crystalluria of magnesium ammonium phosphate secondary to urinary infection due to the association of two germs: Citrobacter freundii (non ureolytic) and Morganella morgagnii (ureolytic). Clinical Case. A 72-year-old woman with no prior urological history who consulted for the past 1 year of expulsion of a large amount of sand in the micturition, to the point that she had occasion ally occluded the urethra. The patient provided a sample of the crystalluria (sand) recovered from the dry sediment of her urine, where a large volume of dust and sand (microcrystals) was seen. The study of the urine sediment showed PH 8, density of 1035 (n 1005-1030), nitrites (+), bacteriuria and abundant amount of colorless crystals in the form of prism or "coffin" suggestive of corresponding magnesium ammonium phosphate crystals. In the urinoculture there were 500,000 CFU / ml and two non-ureolytic (Citrobacter freundii) and one ureolytic (Morganella morgagnii) were isolated. Simple x-ray of normal urinary system and ultrasound. The chemical analysis of the grit showed a composition of 80 pertcent magnesium ammonium phosphate and 20 pertcent calcium oxalate. Therapy was initiated according to antibiogram with ciprofloxacin 500 mg every 12 hours 7 days and the urine was acidified with vitamin C (ascorbic acid) 500 mg day 20, succeeding in eradicating the urinary tract infection, normalizing the urinary pH to 5, and finally stopping expulsion Of crystals. In a control at 6 months, he remained asymptomatic and with sterile urine culture. Conclusions. This case is an exceptional presentation of a urethritic urinary infection, without the usual classic symptoms. Its only clinical manifestation was the expulsion of large amounts of crystals (sand) in micturitions that occasionally caused intermittent urethral obstructions of spontaneous resolution. This unique case demonstrates that listening to patients, sometimes tell us almost impossible facts and most of the time are true.(AU)

Detection of integrons and ISCR1 in and genotyping of NDM-1-producing Citrobacter freundii / 中国感染与化疗杂志

Objective To investigate the distribution of integrons and ISCR1 elements in NDM-l-producing Citrobacterfreundii isolates,and analyze the genotypes of these strains to understand their homology.Methods A total of 18 strains of NDM-1-producing Citrobacterfreundii were collected from the First Affiliated Hospital of Kunming Medical University during the period from June 2012 and October 2014.The isolates were identified and subjected to antimicrobial susceptibility testing with VITEK 2 System.Class Ⅰ,Ⅱ,and 1Ⅲ integrons and ISCR1 elements were detected by PCR.Clonal relatedness was assessed by pulsed field gel electrophoresis (PFGE).Results Most (77.8％,14/18) strains were positive for class Ⅰ integron conserved region,27.8％ (5/18) isolates were positive for ISCR1 conserved region.No class Ⅱ or Ⅲ integron was detected.Most (72.2％,13/18) isolates were positive for class Ⅰ integron variable region.None of the strains harbored class Ⅱ integron or ISCR1 variable region.Integron variable regions included gene cassette encoding resistance to aminoglycosides (aadA1,aadA5,aac(6')-Ib-cr) and trimethoprim-sulfamethoxazole (dfrA,dfrA15,dfrA17).PFGE revealed 17 clusters among 18 NDM-l-producing Citrobacter freundii isolates.Conclusions The clonal dissemination of NDM-l-producing Citrobacterfreundii isolates is not significant.Class I integron is prevalent in NDM-l-producing Citrobacter freundii.The presence of ISCR1 is relatively rare.The two mobile elements are not related to the spread of NDM-1 gene in this hospital.

Study on drug resistance mechanism in carbapenem-resistant Citrobacter freundii and treatment strategies / 重庆医学

Objective To explore the drug resistance mechanisms of carbapenem-resistant Citrobacter freundii (C.freundii) and its treatment strategies.Methods Clinical data of 17 strains of carbapenem-resistant C.freundii from this hospital were collected.Carbapenemase resistant genes were amplifies by polymerase chain reaction (PCR).The agar dilution method and the broth dilution method were used to determine the minimal inhibition concentration (MIC) of single antimicrobial drug and drug combination,the partial inhibitory concentration index (Σ FICI) was calculated.Results Eight strains were found to produce blaNDM-1 and 9 strains produced blaIMP,blaKPC,blaSPM and blaoxA-48 were not detected in the study.Furthermore,the synergistic effect and addictive effect of fosfomycin combined imipenem accounted for 75.00％,in which,the synergistic effect was up to 56.25 ％.the synergistic effect and addictive effect of fosfomycin and cefoperazone/sulbactam accounted for 50.00％.Conclusion Fosfomycin combined with imipenem or cefoperazone/sulbactam has good antibacterial activity in vitro,but imipenem combined with fosfomycin may have better effect.

Study on drug resistance mechanism in carbapenem-resistant Citrobacter freundii and treatment strategies / 重庆医学

Objective To explore the drug resistance mechanisms of carbapenem-resistant Citrobacter freundii (C.freundii) and its treatment strategies.Methods Clinical data of 17 strains of carbapenem-resistant C.freundii from this hospital were collected.Carbapenemase resistant genes were amplifies by polymerase chain reaction (PCR).The agar dilution method and the broth dilution method were used to determine the minimal inhibition concentration (MIC) of single antimicrobial drug and drug combination,the partial inhibitory concentration index (Σ FICI) was calculated.Results Eight strains were found to produce blaNDM-1 and 9 strains produced blaIMP,blaKPC,blaSPM and blaoxA-48 were not detected in the study.Furthermore,the synergistic effect and addictive effect of fosfomycin combined imipenem accounted for 75.00％,in which,the synergistic effect was up to 56.25 ％.the synergistic effect and addictive effect of fosfomycin and cefoperazone/sulbactam accounted for 50.00％.Conclusion Fosfomycin combined with imipenem or cefoperazone/sulbactam has good antibacterial activity in vitro,but imipenem combined with fosfomycin may have better effect.

Distribution and Drug Resistance of Carbapenem-resistant Citrobacter Freundii from 2012 to 2014 / 昆明医科大学学报

Objective To investigate the distribution and susceptibility of carbapenem resistant citrobacter freundii for rational antimicrobial therapy.Methods The C.freumdii were collected between January 2011 and December 2014 from inpatients.The minimum inhibitory concentration (MIC) were detected by an automated analyzer (VITEK 2) to analyze the characteristic of tested bacteria.Results (1) Of the 21 strains of carbapenemresistant citrobacter freundii,95％ were collected from urine,among which most of the strains were isolated from the Department of Transplantology (66.7％) and Urology (19％);(2) Antimicrobials Susceptibility test showed that Citmbacter freund were highly resistant to Cephalosporins and relevant beta-lactamase inhibitors.Even carbapenem were highly resistant.Imipenem had a resistance rate of 90％ (95％ confidence interval:70 to 99),Meropenem 85.7％ (95％ confidence interval:64 to 97),The drug resistance rate to Amikacin was only 4.8％,followed by Nitrofuran toin (10.5％) and Fosfomycin (15％).Conclusions Carbapenem resistant citrobacter freundii,which often causes urinary tract infection in our hospital,was characterized by multi-drug resistant (MDR).Monitoring of the Citrobaeter freundii should be strengthened to control the prevalence of drug resistance.

Analysis of the etiology and drug resistance of hospital infection in critically ill patients caused by 132 Citrobacter freundii / 国际检验医学杂志

Objective To analysis of the causes and drug resistance characteristics in ICU patients with Citrobacter freundii hos‐pital infections ,for the future of clinical treatment and prevention of Citrobacter freundii infection provides the basis .Methods Col‐lected our hospitals from December 2011 to November 2014 clinical samples of ICU patients ,conventional isolation and culture of bacteria ,K‐B disk diffusion susceptibility test ,using Whonet5 .6 software analysis processing tentative data .Results Isolated from Critically ill patients Citrobacter freundii lower respiratory tract ,accounted for 64 .4% ;ESBLs producing high ,accounted for 35 .6% ;susceptibility testing showed the bacteria to imipenem ,meropenem ,nitrofurantoin ,kanamycin ,amikacin ,cefoperazone/sul‐bactam and piperacillin/tazobactam were more sensitive ,drug resistance rates were 3 .8% ,4 .5% ,8 .3% ,9 .1% ,17 .4% ,18 .1% and 22 .7% ,the rest of antimicrobial drug resistance rates more than 25 .0% .Conclusion Citrobacter freundii caused critically ill pa‐tients hospital infection have become increasingly serious ,lower respiratory tract was the main site of infection ,the bacteria used in the clinic for cephalosporin ,quinolones ,aminoglycosides and a variety of internal β‐lactam antibiotics were highly resistant ,clinicians should strengthen monitoring of drug resistance ,to reduce the resistant strains produced and spread within the hospital .

Distribution and Antibiotic Susceptibility Pattern of Bacterial Pathogens Causing Urinary Tract Infection in Mubi General Hospital, Yola-Nigeria.

Aims: This study was conducted to determine the distribution and antimicrobial susceptibility of uropathogens among patients attending Mubi general hospital as well as to determine the effect of gender on the etiology of bacterial uropathogens. Study Design: Distributions of urinary isolates and their antibiogram Place and Duration of Study: Mubi General Hospital, Adamawa State, between April, 2013 and January, 2014 Methodology: Urine samples of 101 patients comprised of 46 males and 55 females were analyzed for bacterial growth, antibiogram and multiple antibiotic resistance index. Results: Females showed higher prevalence of UTI than males. Gram negative bacteria (61.7%) were found in high prevalence than Gram positive (29.3%). Staphylococcus aureus (58.3%) has the highest prevalence rate among Gram positive organisms, while Citrobacter freundii (25.3%) was the most prevalent Gram negative isolates. Citrobacter freundii (17.9%) was the most prevalent uropathogens closely followed by S. aureus (17.1%). Antimicrobial susceptibility was performed on all isolated bacteria by the disc diffusion method employing multiple antibiotic discs differently for both Gram positive and Gram negative isolates. The results showed that S. aureus and Coagulase Negative Staphylococci (CoNS) were more susceptible to Chloramphenicol (83%), followed by Streptomycin and Amoxicillin (78%). While their resistance profile showed that S. aureus and CoNS are more resistant to Ampiclox, Gentamycin and Rifampicin (31%). Susceptibility to all the antibiotics by Gram positive organisms was significantly higher than their resistance to the same antibiotics (p< 0.05). Gram negative organisms are more susceptible to Streptomycin (62%), followed by Ciprofloxacin (47%) and Ofloxacin (44%), while their resistance profile showed that they are more resistance to Nalixidic acid (79%) followed by Augmentin (76%), Ampicillin (75%) and Reflacine (74%). Resistance to all the antibiotics by Gram negative organisms is significantly higher than their susceptibility to the same antibiotics (p<0.05). Using spearman correlation, the results further showed significant correlation in resistance between P. vulgaris, Escherichia coli and P. agglomerans (p<0.01). Also, there was significant correlation in resistance between E. coli, Klebsiella sp., Citrobacter diversus and P. vulgaris (p<0.05). The multiple antibiotic resistances (MAR) index of each antibiotic was calculated. The MAR index for Gram positive antibiotics was significantly lower than that of Gram negative antibiotics (p<0.05). Conclusion: In this study, we found multidrug resistance strains which are resistant to most of the antimicrobials agent tested more especially the Gram negative uropathogens. This reflected the fact that Nalixidic acid, Augmentin, Ampicillin, Reflacine, Ceporex and Septrin were the most commonly prescribed antibiotics in the hospital even before the results of urine analyses and also the most easily available in the market without prescription and because they were also very cheap in terms of cost. Consequently, the widespread use or misuse of antimicrobial drugs has led to a general rise in the emergence of resistant bacteria.

Emphysematous Pyelonephritis Caused by Citrobacter freundii in a Patient with Type 2 Diabetes and Neurogenic Bladder / 감염과화학요법

Emphysematous pyelonephritis (EPN) is a rare, life-threatening complication of upper urinary tract infections that is characterized by the presence of gas in the renal parenchyma and perirenal space. It commonly occurs in diabetic patients. Escherichia coli are the most common causative organisms, with few reports implicating Citrobacter freundii as the etiologic agent in EPN. A 57-year-old woman with diabetes and neurogenic bladder visited at our department with confused mentality, myalgia, and general weakness. Further investigation revealed that the patient suffered from unilateral EPN with sepsis caused by C. freundii. The patient's condition was improved considerably with percutaneous drainage and use of intravenous antibiotics for several weeks. However, renal function eventually deteriorated to permanent renal failure, which required hemodialysis. In conclusion, C. freundii may be the causative pathogen of EPN in a patient with type 2 diabetes and neurogenic bladder.

Celulitis facia odontogénica severa infrecuent causada por citrobacter freunddii productora de ampc en un paciente con diabetes mellitus 2. reporte de caso / Uncmmon severe oodontogenic facial cellulitis caused by ampcproducing citrobacter freundii in a patient with type 2 diabetes mellitus. case report / Celulite facial odontogênica sevea infrequente causada por citrobacter freundii produtora de ampc em um paciente com diabetes mellitus 2. relatório e caso

El manejo de la celulitis facial odontogénica no deja de ser un tema controversial en el campo de la cirugía oral y maxilofacial; los principios quirúrgicos y terapéuticos han sido sometidos a modificacio nes basadas en los hallazgos clínicos, imagenológicos y microbiológicos a través del tiempo. En pacientes con diabetes mellitus 2 se incrementa el riesgo a sufrir infecciones bacterianas oportunistas con tiempos de hospitalización más prolongados que la población no diabética. La literatura es clara estableciendo las diferencias clínicas y microbiológicas de la celulitis facial odontogénica en este grupo de pacientes, sin embargo, no existe un protocolo médico quirúrgico destinado a ellos. El microorganismo comúnmente aislado es Klebsiella pneumoniae, mientras Citrobacter freundii es inusual en las infecciones odontogénicas, su capacidad para producir betalactamasas de amplio espectro (AmpC) le permite bloquear la acción de los antibióticos de uso empírico en Cirugía Oral y Maxilofacial. A continuación, presentamos el caso de una paciente de 61 años con diabetes Mellitus tipo 2 y celulitis facial odontogénica por Citrobacter freundii productora de AmpC.

The management of odontogenic facial cellulitis is still a controversial issue in the field of Oral and Maxillofacial Surgery. Surgical and therapeutic principles have undergone modifications based on clinical findings, imaging and microbiological over time. In patients with type 2 Diabetes Mellitus the risk of opportunistic bacterial infections is increased thus suffering longer hospitalization periods than the nondiabetic population. The literature is clear by setting the clinical and microbiological differences of odontogenic facial cellulitis in this group of patients, but there is no surgical medical protocol for them. Klebsiella pneumoniae is the most common microorganism isolated while Citrobacter freundii is unusual in relation to oral infections; their ability to produce ESBLs (AmpC) allows them to block the action of empirical antibiotics used in Maxillofacial Surgery. We present the case of a 61 year old patient with type 2 Diabetes Mellitus and odontogenic facial cellulitis caused by AmpCproducing Citrobacter freundii.

O tratamento da celulite facial odontogênica não deixa de ser um tema controverso no campo da Cirurgia Oral e Maxilofacial; os princípios cirúrgicos e terapêuticos foram submetidos a modificações baseadas nos descobrimentos clínicos, imagenológicos e microbiológicos através do tempo. Em pacientes com Diabetes Mellitus 2 aumenta o risco de sofrer infecções bacterianas oportunistas com tempos de hospitalização mais prolongados que na população não diabética. A literatura é clara estabelecendo as diferenças clínicas e microbiológicas da Celulite Facial Odontogênica neste grupo de pacientes; porém, não existe um protocolo médico cirúrgico destinado a eles. O microrganismo comunmente isolado é o Klebsiella pneumoniae, enquanto que o Citrobacter freundii é inusual nas infecções odontogênicas, sua capacidade para produzir betalactamases de amplo espectro (AmpC) lhe permite bloquear a ação dos antibióticos de uso empírico em Cirurgia Oral e Maxilofacial. A seguir apresentamos o caso de uma paciente de 61 anos com Diabetes Mellitus tipo 2 e celulite facial odontogênica por Citrobacter freundii produtora de AmpC.

Abdominal Aortic Aneurysm Infection Caused by Citrobacter freundii

Citrobacter freundii is frequently isolated in antimicrobial-resistant nosocomial infections. Many strains of Citrobacter freundii are capable of producing an inducible broad-spectrum beta-lactamase. We report a case of an abdominal aortic aneurysm infected with Citrobacter freundii. A 55-year-old woman presented with acute lower back pain. Contrast enhanced computed tomography revealed a saccular aneurysm of the infrarenal abdominal aorta, with impending rupture. She underwent emergency surgery, during which a segment of aneurysmal aorta and infected tissue were completely removed and an in situ graft was placed for vascular reconstruction. The anastomotic site and inserted graft were wrapped with greater omentum. Citrobacter freundii was isolated by tissue culture from the resected aneurysmal wall.

Cloning, Sequence Analysis and Expression of dhaT Gene from Citrobacter freundii and Purification and Property of Corresponding Recombinant Enzyme / 中国生物工程杂志

1,3-propanediol (1,3-PD) is an important material for chemical industry, therefore, there is much interest in the production of 1,3-PD. The gene dhaT encoding 1, 3-propanediol dehydrogenase ( PDOR) of Citrobacter freundii was amplified by PCR. Sequence analysis of the similarity at the nucleotide and amino acid level between the gene encoding C. freundii PDOR and that of C. freundii ( U09771 ) were 78% and 90% , respectively. The recombinant plasmid pSE-dhaT was constructed by inserting dhaT gene into expression vector pSE380 and then transformed E. coli JM109. The recombinant strain was induced by IPTG to express dhaT. Further more the recombinant enzyme was purifed from recombinant E. coli by Ni-nitrilotriacetate affinity chromatography followed by Sephacral S-300 gel filtration. A single obvious protein about 42kDa could be obtained by the sodium dodecyl sulfate-polyacrylamide gel electrophoresis of recombinant enzyme. The purified enzyme was used to determined enzyme property on the substrate of propionaldehyde and 1, 3-PD. The optimal temperature and optimal pH of the purified enzyme were 37℃, 8.0 for reduction and 25℃, 10. 5 for oxidation, respectively; and the kinetic property of PDOR about Km and V max were 10. 05mmol/L, 37. 27?mol/min/mg for propionaldehyde and 1. 28mmol/L, 25. 55?mol/min/mg for 1,3-PD, respectively; The deduced dhaT gene product (388 amino acids) showed a specific reduction activity of 49. 50U/mg and oxidation activity of 79. 92U/ mg. There also have a putative iron-binding motif ( G-XX-H-X-X-A-H-X-X-G-X-X-X-X-X-P-H-G) as a fingerprint pattern in the recombinant enzyme, the motif is fully conserved among these 1, 3-propanediol dehydrogenase. It is beneficial to the researches of high producing 1, 3-propanediol by gene engineering strain.