PUBLICACIONES SOBRE ITUS Y SENSIBILIDAD DE UROPATOGENOS  
  Alexiou Z
Mouktaroudi M
Koratzanis G
Papadopoulos A
Kavatha D
Kanellakopoulou K
Giamarellou H
Giamarellos-Bourboulis EJ
 
  4th Department of Internal Medicine, University of Athens, Medical School, Athens, Greece;
1st Department of Internal Medicine, Thriaseio General Hospital, Elefsina, Greece.
  The significance of compliance for the success of antimicrobial prophylaxis in recurrent lower urinary tract infections: the Greek experience  
  Int J Antimicrob Agents. 2007 Jul;30(1):40-3. Epub 2007 Apr 24.

In an attempt to define the most important driver responsible for recurrence of cystitis in women, 181 records were retrospectively analysed among 1010 consecutive references in a tertiary centre for lower urinary tract infections (UTIs). All 181 women had more than three episodes of cystitis per year; 129 were under continuous prophylaxis and 52 were under postcoital prophylaxis. Analysis revealed that the most important factor affecting successful outcome of chemoprophylaxis was the compliance of patients (odds ratio 0.074; P<0.0001). Among women treated for >/=6 months, the most effective regimen was nitrofurantoin, with a success rate of 96.8% compared with 82.8% for trimethoprim/sulphamethoxazole and 72.3% for norfloxacin (P=0.046 between agents). Failure of chemoprophylaxis was observed in 51 women in total; in 26 of them resistance to the administered agent had developed. Results of this retrospective study revealed that the most important driver leading to failure of prophylaxis for recurrent lower UTIs was the lack of compliance of women with their medication. Nitrofurantoin was the most potent among the administered agents.

PMID: 17459663 [PubMed - in process]
 
   
 





Alós JI

García-Peña P
Tamayo J
  Servicio de Microbiología, Hospital de Móstoles, Móstoles, Madrid. España
nachoalos@microb.net
  Biological cost associated with fosfomycin resistance in Escherichia coli isolates from urinary tract infections
 

Rev Esp Quimioter. 2007 Jun;20(2):211-5

Resistance to fosfomycin develops rapidly in experimental conditions, although despite its frequent use in UTI, resistance in E. coli, the main uropathogen, is very low (1-3%), and has remained so for many years. The objective of this study was to ascertain whether E. coli fosfomycin-resistant strains have less fitness than those that are fosfomycin-sensitive in competing, and would therefore tend to disappear in their competition with fosfomycin-sensitive strains in the absence of antibiotics. Fosfomycin-resistant strains (n=11) with different phenotypes of resistance to other antibiotics were used. All but one were lactose (+). Fosfomycin-susceptible strains (n=15) that had the same phenotypes of resistance to other antibiotics as the resistant strains and which had the opposite pattern of lactose fermentation were also used. Thirty-three (33) competition experiments by pairs of strains were conducted in nutrient broth. Equal amounts of the strains were challenged (approx. 50% and approx. 50%) for 4 days, with a daily change to a new medium. Five differential counts were performed on days 0, 1, 2, 3 and 4. In 20 experiments (60.6%) there was a relative increase in the fosfomycin-sensitive strain. In 6 experiments (18.2%) there was a relative increase in the fosfomycin-resistant strain. In 7 experiments (21.2%), on the fourth day none of the strains reached 60%. When the data of the 26 (20+6) experiments in which there were changes were analyzed by the chi2 test there was a statistically significant difference (p=0.044). Resistance to fosfomycin could entail a biological cost (less fitness) for the majority of the E. coli strains assayed.

PMID: 17893758 [PubMed - indexed for MEDLINE]

   
 





Andersson M

Uhlin BE
Fällman E.
 

Department of Physics, Umeå University, Umeå, Sweden.

  The biomechanical properties of E. coli pili for urinary tract attachment reflect the host environment
  Biophys J. 2007 Nov 1;93(9):3008-14. Epub 2007 Aug 3.

Uropathogenic Escherichia coli express pili that mediate binding to host tissue cells. We demonstrate with in situ force measuring optical tweezers that the ability of P and type 1 pili to elongate by unfolding under exposure to stress is a shared property with some differences. The unfolding force of the quaternary structures under equilibrium conditions is similar, 28 +/- 2 and 30 +/- 2 pN for P pili and type 1 pili, respectively. However, type 1 pili are found to be more rigid than P pili through their stronger layer-to-layer bonds. It was found that type 1 pili enter a dynamic regime at elongation speeds of 6 nm/s, compared to 400 nm/s for P pili; i.e., it responds faster to an external force. This possibly helps type 1 to withstand the irregular urine flow in the urethra as compared to the more constant urine flow in the upper urinary tract. Also, it was found that type 1 pili refold during retraction at two different levels that possibly could be related to several possible configurations. Our findings highlight functions that are believed to be of importance for the bacterial ability to sustain a basic antimicrobial mechanism of the host and for bacterial colonization.

PMID: 17675342 [PubMed - indexed for MEDLINE]
   
 





Andersson M
Uhlin BE
Fällman E.
  Department of Physics, Umeå University, Umeå, Sweden.

  The biomechanical properties of E. coli pili for urinary tract attachment reflect the host environment
  Biophys J. 2007 Nov 1;93(9):3008-14. Epub 2007 Aug 3.

Uropathogenic Escherichia coli express pili that mediate binding to host tissue cells. We demonstrate with in situ force measuring optical tweezers that the ability of P and type 1 pili to elongate by unfolding under exposure to stress is a shared property with some differences. The unfolding force of the quaternary structures under equilibrium conditions is similar, 28 +/- 2 and 30 +/- 2 pN for P pili and type 1 pili, respectively. However, type 1 pili are found to be more rigid than P pili through their stronger layer-to-layer bonds. It was found that type 1 pili enter a dynamic regime at elongation speeds of 6 nm/s, compared to 400 nm/s for P pili; i.e., it responds faster to an external force. This possibly helps type 1 to withstand the irregular urine flow in the urethra as compared to the more constant urine flow in the upper urinary tract. Also, it was found that type 1 pili refold during retraction at two different levels that possibly could be related to several possible configurations. Our findings highlight functions that are believed to be of importance for the bacterial ability to sustain a basic antimicrobial mechanism of the host and for bacterial colonization.

PMID: 17675342 [PubMed - indexed for MEDLINE]

   
 


Arreguín V

Cebada M
Simón JI
Sifuentes-Osornio J
Bobadilla-del Valle M
Macías AE
  Laboratorio Clinico, Centro Médico ABC, DF México
vickyarna@yahoo.com
  Microbiology of urinary tract infections in ambulatory patients. Therapeutic options in times of high antibiotic resistance
  Rev Invest Clin. 2007 Jul-Aug;59(4):239-45. Links

OBJECTIVE: To determine the antibiotic resistance of urinary pathogens in ambulatory patients from Mexico City, in order to infer therapeutic options in environments of high resistance. METHODS: Cross sectional survey performed between July 2006, and January 2007, in patients > or =3 year-old from a private institution. Cultured organisms were identified with a commercial biochemical system. For common antibiotics, susceptibility was performed by broth microdilution with a commercial system; for fosfomycin tromethamine, the disk diffusion test was performed. RESULTS: From 1685 urine specimens, 257 (15.3%) yielded a positive culture; 215 (83.7%) from women and 42 (16.3%) from men. Global resistance was the following: ampicillin, 68.4%; co-amoxiclav, 19.5%; ciprofloxacin, 36.3%; cephalothin, 64.7%; ceftriaxone, 12.2%; cefuroxime, 18.7%; nitrofurantoin, 19%; trimethoprim-sulphamethoxazol, 53.4%; gentamicin, 18.9%; and fosfomycin tromethamine, 0.8%. Escherichia coli was the main pathogen, with 203 (79%) isolations; its specific resistance was similar to the global one, and its production of extended-spectrum beta-lactamases (ESBLs) was 9.4%. CONCLUSIONS: The high resistance rate found is alarming; we have few options for the initial treatment of urinary tract infections in ambulatory patients. To control the problem, health authorities must regulate the indiscriminate use of antibiotics.

PMID: 18019596 [PubMed - in process]
   
 






Aykut Arca E

Karabiber N
 

Türkiye Yüksek Ihtisas Egitim ve Araştirma Hastanesi, Mikrobiyoloji Laboratuvan, Ankara.

  Short communication: comparison of susceptibilities of Escherichia coli urinary tract isolates against fosfomycin tromethamine and different antibiotics
  Mikrobiyol Bul. 2007 Jan;41(1):115-9.

The aim of this study was to investigate the susceptibilities of Escherichia coli strains isolated from urine samples, against fosfomycin tromethamine and different antibiotics in the period of October-December 2004 in a local hospital in Ankara, Turkey. A total of 120 E. coli strains isolated from urine cultures of subjects who were admitted to outpatient clinics were included to the study. The identification and antimicrobial susceptibility tests (against amikacin, amoxicillin/clavulanate, ampicillin, cefepime, cefoxitin, cefotaxime, cefuroxime, cefalotin, ciprofloxacin, gentamicin, levofloxacin, meropenem, nitrofurantoin, piperacillin, piperacillin/tazobactam and trimethoprim/sulphametoxazole) were performed by a commercial automatized system (Phoenix, Becton Dickinson, USA). Fosfomycin tromethamine susceptibility was studied by Kirby Bauer disk diffusion method according to the CLSI criteria. Only one strain (0.8%) was found resistant to fosfomycin tromethamine, while no resistance was determined against amikacin and meropenem. Most of the isolates were found susceptible to nitrofurantoin (90%), cefoxitin (82.5%), gentamicin (81%), piperacillin/tazobactam (81%), cefepime (79%) and cefotaxime (%79%). All of the E. coli isolates which were resistant to ciprofloxacin and levofloxacin (44% and 43%, respectively) were found susceptible to fosfomycin tromethamine. In conclusion, since E. coli is by far the most prevalent community acquired urinary tract pathogen, fosfomycin tromethamine seems to be a reasonable alternative for the ampirical therapy of uncomplicated urinary tract infections.

PMID: 17427560 [PubMed - in process]
   
  Baba-Moussa L
Anani L
Scheftel JM
Couturier M
Riegel P
Haïkou N
Hounsou F
Monteil H
Sanni A
Prévost G.

  Laboratoire de Biochimie et Biologie Moléculaire, FAST, Université d'Abomey-Calavi, Cotonou, Bénin.
  Virulence factors produced by strains of Staphylococcus aureus isolated from urinary tract infections
  J Hosp Infect. 2007 Dec 5 [Epub ahead of print]

Staphylococcus aureus infections are widely prevalent in West Africa and are often associated with urinary tract infections (UTIs). Virulence factors from S. aureus have rarely been described for such infections. The purpose of the current study was to determine the prevalence of toxins and adhesion factors obtained from S. aureus isolated from presumed primary UTIs at the Cotonou University Hospital (CUH) in Benin as compared with the Strasbourg University Hospital (SUH) in France. Both ambulatory and hospitalised patients were included in the study. Sixty-five independent strains of S. aureus from CUH and 35 strains from SUH were obtained over a four-month period. Virulence factors were characterised by immunodetection or multiplex polymerase chain reaction, and meticillin susceptibility was recorded. Approximately 50% of all isolates produced at least one enterotoxin. No isolate from SUH produced Panton-Valentine leucocidin (PVL), whereas 21.5% of the S. aureus isolates from CUH produced PVL (P<0.01). Six of 14 (43%) PVL-positive isolates were meticillin-resistant. At SUH, the incidence of MRSA (57%) was significantly higher (P<0.01) than at CUH (14%). Genes encoding clumping factor B, and elastin and laminin binding proteins were detected in almost all isolates (80%), irrespective of the geographical origin. The results for elastin binding protein differed significantly from published data regarding isolates from other clinical origins. Staphylococcal toxins and adhesion factors may be important in the physiopathology of UTI.

PMID: 18069084 [PubMed - as supplied by publisher]
   
 

Bayrak O

Cimentepe E
Inegöl I
Atmaca AF
Duvan CI
Koç A
Turhan NO.
  Department of Urology, Fatih University School of Medicine, Alpaslan Türkeş cad., 06510 Emek, Ankara, Turkey. omerbayrak69@yahoo.com
  Is single-dose fosfomycin trometamol a good alternative for asymptomatic bacteriuria in the second trimesterof pregnancy?
  Int Urogynecol J Pelvic Floor Dysfunct. 2007 May;18(5):525-9. Epub 2006 Aug 29.

Untreated asymptomatic bacteriuria has been associated with acute pyelonephritis, which may have a role in many maternal and fetal complications. Acute pyelonephritis in pregnancy is related to anemia, septicemia, transient renal dysfunction, and pulmonary insufficiency. A randomized study was conducted to assess the clinical and microbiological efficacy of a single dose of fosfomycin trometamol for the treatment of asymptomatic bacteriuria in the second trimester of pregnancy compared with a 5-day regimen of cefuroxime axetyl. Forty-four women received fosfomycin trometamol and 40 women received cefuroxime axetyl. There were no statistically significant differences between both groups regarding the mean age and mean duration of pregnancy. Therapeutic success was achieved in 93.2% of the patients treated with fosfomycin trometamol vs 95% of those treated with cefuroxime axetyl. A single dose of fosfomycin trometamol is a safe and effective alternative in the treatment of asymptomatic urinary tract infections in the second trimester of pregnancy.

PMID: 16941068 [PubMed - indexed for MEDLINE]

   
 



Cantón Ra
Valverde Aa
Novais Aa
Baquero Fa
Coque Ta
  aServicio de Microbiología. Hospital Universitario Ramón y Cajal. Madrid. España.
  Infecciones por microorganismos productores de betalactamasas de espectro extendido (BLEE): un desafío epidemiológico y terapéutico. Evolución y panorama actual de las BLEE
  Enferm Infecc Microbiol Clin 2007; 25: 2 - 10

Las betalactamasas de espectro extendido (BLEE), enzimas capaces de hidrolizar las cefalosporinas de amplio espectro y los monobactams, pero no las cefamicinas o los carbapenemes, fueron detectadas por primera vez en Alemania en 1983, y en España a partir del año 1988. Suponen un modelo de evolución y un escalón más en el incremento de la resistencia a los antimicrobianos. A las enzimas inicialmente descritas de las familias SHV y TEM se han unido otras con mayor dispersión, las CTX-M, y otras con menor prevalencia (PER, BES, GES, IBC, BEL). La epidemiología de las BLEE ha tenido diferentes períodos desde su descripción, que incluyen epidemias, casos esporádicos, situaciones de alodemia (policlonalidad) y epidemias de elementos genéticos (plásmidos) asociados a ellas. La distribución actual de los microorganismos con BLEE y de estas enzimas varía de unas zonas geográficas a otras, aunque debido a un aumento en su dispersión asistimos a una situación pandémica. En general, se detectan mayoritariamente en Escherichia coli, sobre todo en pacientes con infecciones adquiridas en la comunidad, produciéndose un flujo de aislados desde este ambiente al medio hospitalario. El incremento de los microorganismos con BLEE atendería a un proceso multifactorial que incluiría tanto los elementos y estructuras genéticas asociadas a los genes blaBLEE como a los microorganismos que las producen, sus resistencias asociadas y los procesos de coselección.

Palabras clave: Betalactamasas de espectro extendido. Infección adquirida en la comunidad. Escherichia coli.
   
 




Caro Narros MRa
Hernando Real Sa
Carrero González Pa
García Carbajosa Sa
  aSección de Microbiología. Servicio de Análisis Clínicos. Complejo Asistencial de Segovia. Segovia. España.

  Estudio de multirresistencia antibiótica de Escherichia coli en urocultivos
  Med Clin (Barc) 2007; 129: 409 – 411

Fundamento y objetivo: La aparición de resistencias en las infecciones del tracto urinario causadas por Escherichia coli constituye un importante problema terapéutico que requiere estudiar su evolución en el tiempo para instaurar un tratamiento empírico adecuado. Nuestro objetivo fue conocer la sensibilidad antimicrobiana de los aislamientos de E. coli en urocultivos en nuestra área. Material y método: Se analizaron retrospectivamente 5.247 aislamientos de E. coli procedentes de urocultivos de pacientes hospitalarios y extrahospitalarios en la provincia de Segovia. Se estudió la sensibilidad antibiótica de los aislamientos realizados en 2000-2005 y se analizaron 6 patrones fenotípicos de resistencia a betalactámicos: salvaje, producción de penicilinasa, hiperproducción de penicilinasa, productor de IRT (inhibitor resistant TEM mutants), hiperproducción de adenosinmonofosfato cíclico (AMPc) y betalactamasas de espectro extendido (BLEE), así como la diferencia de sensibilidad entre cepas productoras y no productoras de BLEE a la nitrofurantoína, la fosfomicina, el ciprofloxacino, la gentamicina y la trimetoprima-sulfametoxazol. Resultados: Un 57% fue resistente a ampicilina; un 23%, a ciprofloxacino y un 31%, a trimetoprima-sulfametoxazol. Un 48% fue productor de penicilinasa; un 6,6%, de penicilinasa incrementada; un 1,2%, de IRT; un 1,1%, de AMPc hiperproducido y un 2,2%, de BLEE, sin diferencias estadísticamente significativas en cuanto a la procedencia de la muestra. Se encontraron porcentajes de resistencia combinada a ciprofloxacino y trimetoprima-sulfametoxazol muy superiores en cepas productoras de BLEE, y se observó un incremento paulatino en la expresión de este mecanismo de resistencia durante el período estudiado. Conclusiones: Ampicilina, ciprofloxacino y trimetoprima-sulfametoxazol no son recomendables en el tratamiento empírico de las infecciones urinarias no complicadas en nuestra área. Los estudios de sensibilidad son esenciales con el fin de instaurar tratamientos empíricos correctos.

Palabras clave: Infección urinaria. Escherichia coli. Sensibilidad antibiótica. Fenotipos. Multirresistencia.
   
 








Cisneros JMa
Cordero Ea

  aServicio de Enfermedades Infecciosas. Hospital Universitario Virgen del Rocío. Sevilla. España.
  Infecciones por microorganismos productores de betalactamasas de espectro extendido (BLEE): un desafío epidemiológico y terapéutico

Relevancia de las BLEE en el pronóstico y coste de las infecciones
  Enferm Infecc Microbiol Clin 2007; 25: 48 - 53

La diseminación de las enterobacterias productoras de betalactamasas de espectro extendido (BLEE) es un problema creciente. La principal consecuencia de esta circunstancia ha sido la pérdida de eficacia de la hasta ahora principal familia de antibacterianos usados en las infecciones graves: las cefalosporinas de tercera y cuarta generación. En este capítulo se hace una revisión de las consecuencias de este nuevo mecanismo de resistencia en el pronóstico de las infecciones producidas por estas bacterias. Los aspectos relacionados con el pronóstico que se discuten son: a) la relación entre el pronóstico y la producción de BLEE, b) la virulencia de las cepas, c) los factores pronósticos de las infecciones por bacterias productoras de BLEE, d) la relación del pronóstico y el tratamiento empírico inapropiado y el tipo de antibiótico utilizado, e) la relación con la especie de enterobacteria productora de BLEE, y f) el impacto económico de las infecciones por cepas productoras de BLEE.

Palabras clave: Pronóstico. BLEE. Coste. Enterobacterias.
   
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