Page kidney after pediatric kidney transplantation: a case report. / Riñón de Page tras trasplante renal pediátrico: informe de un caso.

INTRODUCTION: Page kidney (PK) is a rare condition caused by parenchymal compression due to a subcapsular hematoma. Irreversible damage of the graft may occur if this condition is not recognized and treated properly. CLINICAL CASE: We describe the case of a 16-year-old man with chronic renal failure secondary to corticosteroid-resistant nephrotic syndrome (CRNS) caused by NPHS2 mutations. The patient underwent a 5th fifth living-related KT. The graft was placed intraperitoneally and reperfused well without complications. On the 4th postoperative day his labs demonstrated raising creatinine associated with refractory hypertension, gross hematuria and anemia. Urgent ultrasound revealed a subcapsular hematoma with signs of parenchymal compression. PK phenomenon was suspected and urgent surgical intervention decided. COMMENTS: PK is a rare but an emergence potentially treatable and reversible complication after pediatric KT. Early diagnosis based on clinical suspicion and suggestive imaging are the key points for a favorable outcome.

INTRODUCCION: El riñón de Page (RP) es una enfermedad rara provocada por compresión parenquimatosa debido a un hematoma subcapsular. El injerto puede sufrir daños irreversibles si la enfermedad no se reconoce y se trata de forma adecuada. CASO CLINICO: Describimos el caso de un varón de 16 años con fallo renal crónico secundario a síndrome nefrótico corticorresistente (SNCR) provocado por mutaciones del gen NPHS2. El paciente se somete a un quinto TR de donante vivo. El injerto se coloca en posición intraperitoneal, con una adecuada reperfusión, sin complicaciones. Al cuarto día postoperatorio, sus análisis revelan una subida de la creatinina asociada a hipertensión refractaria, hematuria macroscópica y anemia. La ecografía de urgencia revela hematoma subcapsular con signos de compresión parenquimatosa. Se sospecha RP y se decide intervención quirúrgica de urgencia. COMENTARIOS: El RP es una complicación rara y urgente, aunque a su vez tratable y reversible, tras TR pediátrico. El diagnóstico precoz basado en la sospecha clínica y las imágenes son claves a la hora de conseguir un resultado favorable.

Outcome of kidney transplantation from young pediatric donors (aged less than 6 years) to young size-matched recipients.

INTRODUCTION: Pediatric donation is underutilized because of presumed increased risk of vascular thrombosis (VT) and graft loss. Using young pediatric donors (YPDs) for young pediatric recipients (YPRs) is suggested to be even at greater risk and therefore precluded in many centers. The aim of this study was to analyze the outcome of kidney transplantation (KT) from YPD to age-matched YPR. PATIENT AND METHODS: A retrospective study of 118 pediatric KT performed between January 2007-July 2017. The authors identified KT with YPD (considered as those aged <6 years) and age-matched YPR. Organ allocation was performed based on the best paired size (YPR for YPR). Data were collected regarding donor and recipient characteristics, surgical and urological complications, graft loss, and outcomes. RESULTS: Forty cases of YPD to age-matched YPR were identified (33.89% of the cohort). Mean recipient and donor age were 2.9 years (SD 1.68) and 2.24 years (SD 1.5), respectively. Mean recipient and donor weight were 12.7 kg (SD 4.1) and 13.7 kg (SD 4.15), respectively. Thirty of those young recipients (75%) weighed <15 kg. The most frequent primary renal disease was the congenital nephrotic syndrome. Nine out of 40 patients (22.5%) had received a previous KT before. Three received a combined liver-KT. Eight (20%) were classified as high immunological risk and 19 (47.5%) as high thrombotic risk. All allografts were implanted extraperitoneally and anastomosed to the iliac vessels. Major complications requiring reintervention occurred in seven patients (17.5%): three VT, three bleeding episodes, and one ureteral necrosis. Remarkably, only one surgical complication (VT) resulted in graft loss. Regarding long-term urological complications, four patients (10%) all with obstructive uropathy-developed vesicoureteral reflux to the graft. Actuarial graft survival at 1,5, and 10 years in the YPD to age-matched YPR cohort was 83% -78% -78%, respectively. Mean follow-up was 3.6 years (SD 3.2) (r = 7-10). Over time, eight patients lost their graft, not related to surgical factors in seven out of eight cases. CONCLUSION: The authors suggest that KT using YPD for age-match YPR yields good results in expert centers, even in high-risk patients and is associated with good graft survival. In this series, surgical complications were rarely related to graft loss.

[Is the Mathieu urethroplasty a useful technique for urethrocutaneous fistula repair after hypospadias surgery?] / ¿Es la uretroplastia Mathieu una técnica útil para la reparación de fístulas uretrocutáneas en pacientes operados de hipospadias?

AIM: There are multiple surgical techniques for distal urethrocutaneous fistulas (DUCF) repair after hypospadias surgery. Our aim was to analyze our results of simple closure (SC) and salvage mathieu urethroplasty (MU). MATERIAL AND METHODS: Retrospective study (2014-2017) of pediatric patients with DUCF who underwent SC and MU. Only subcoronal to distal fistulas were collected, excluding the proximal ones non-tributary of MU. Demographics, clinical data, treatment and results were registered. MAIN RESULTS: Over 4 years, 177 hypospadias and 28 UCFs were repaired. 15/28 met the inclusion criteria. Hypospadias type: anterior (10, 66.7%), midshaft (3, 20%) and posterior (2, 13.3%). Mean age at primary urethroplasty was 31.9 months (SD: 16.2). The most common techniques in primary surgery were Thiersch-Duplay (6) and Snodgrass (4). Median time from primary surgery to apparition of the fistula was 5 months (rank: 0-14). The surgical technique used for fistula repair was: SC (7) and MU (8). DUCF succeeded in all patients treated with MU, while among those treated with SC, 71.4% recurred, and only 4 patients underwent finally successful repair with a median of 1.5 interventions. Median follow-up was 25 months (rank: 12-55). CONCLUSIONS: MU is a useful, effective and safe technique for DUCF repair. Most importantly, it is easily reproducible. The results of MU seem to be superior to CS and could be considered as a first choice.

OBJETIVO: Existen múltiples técnicas quirúrgicas para el cierre de fístulas uretrocutáneas distales (FUCD) secundarias a la corrección de hipospadias. Nuestro objetivo fue analizar nuestros resultados mediante el cierre simple (CS) y cierre con nueva uretroplastia por técnica de Mathieu (CUM). MATERIALES Y METODOS: Estudio retrospectivo (2014-2017) de pacientes pediátricos con FUCD tratadas mediante CS y CUM. Se incluyeron solo fístulas desde la región subcoronal a distal, excluyendo las fístulas proximales no candidatas de cierre por CUM. Se recogieron datos demográficos, clínicos, tratamiento y resultados. RESULTADOS: Durante 4 años se intervinieron 177 hipospadias y 28 FUC. 15/28 cumplieron los criterios de inclusión. Tipo hipospadias: distal (10; 66,7%), mediopeneano (3; 20%) y proximal (2; 13,3%). La media de edad de la cirugía primaria fue de 31,9 meses (DS:16,2). Las técnicas primarias más utilizadas fueron el Thiersch-Duplay (6) y el Snodgrass (4). La mediana de tiempo desde la cirugía primaria a la aparición de la fístula fue de 5 meses (rango: 0-14). La técnica utilizada para el cierre fue: CS (7) y CUM (8). Todos los pacientes tratados con CUM resolvieron la fístula en un solo tiempo; de los tratados con CS, recidivaron el 71,4%, resolviéndose finalmente 4 con una mediana de 1,5 intervenciones. La mediana de seguimiento fue de 25 meses (rango: 12-55). CONCLUSIONES: El CUM es una técnica útil, eficaz y segura para el tratamiento de la FUCD y, además, fácilmente reproducible. Los resultados del cierre por CUM parecen ser superiores al CS y podría considerarse la técnica de primera elección.

Is donor age 6 years or less related to increased risk of surgical complications in pediatric kidney transplantation?

INTRODUCTION: Despite the widespread organ shortage dilemma, there is hesitancy regarding utilization of young donors (aged ≤6 years) because previous reports have suggested that this is associated with an increased risk of surgical complications and graft loss. OBJECTIVE: The aim of this study was to determine if donor age ≤6 years is related to increased risk of surgical complications or allograft loss in pediatric kidney transplantation (KT). STUDY DESIGN: A retrospective study of pediatric kidney transplants (KT) undertaken between January 2000 and July 2015. The incidence of surgical and urological complications, and allograft loss were analyzed and compared between donors aged ≤6 years (Group 1) and donors aged >6 years (Group 2). RESULTS: A total of 171 pediatric KTs were performed at the current center during the study period. Twenty-eight patients were excluded; as a result, the study comprised 143 patients: 60 (Group 1) and 83 (Group 2). Mean recipient weight was 17 kg (SD 9.7; range 3.2-47) in Group 1 and 38.2 kg (SD 15.3; range 7.8-73) in Group 2. Despite a significantly higher proportion of risk factors in Group 1, no significant between-group differences were observed in terms of: surgical complications (OR 0.4; range 0.1-1.2), early urological complications (OR 2.2; range 0.4-11), late urological complications (OR 0.3; range 0.8-1.4), lymphoceles (OR 6.2; range 0.7-51.7) and allograft loss (OR 1.5; range 0.7-3.1, summary Table). Graft survival at 1 and 5 years was: 81% and 70% (Group 1) and 92% and 79% (Group 2), respectively (P = 0.093). Mean follow-up was 90.13 ± 49.7 months. DISCUSSION: The main finding of this retrospective study was that pediatric donor kidneys from donors aged ≤6 years could safely be used in pediatric recipients without an increased risk of surgical and urological complications or graft loss. Nevertheless, KT with small donor kidneys is challenging and should be performed at experienced pediatric centers. CONCLUSION: In line with these results, the outcomes of KT using donors aged ≤6 years were encouraging and similar to those obtained with older donors. Thus, this study supported using kidney grafts from young donors, given the organ shortage and potential high mortality risk while awaiting KT.

Effect of antibiotics on biofilm inhibition and induction measured by real-time cell analysis.

AIMS: The purpose of the current work was to study the pattern and dynamics of biofilm formation in clinical isolates of Staphylococcus aureus and Staphylococcus epidermidis in the presence of 10 antibiotics with different action mechanisms. METHODS AND RESULTS: By using impedance measurements in microtitre plates with gold electrodes we have assessed the antibiotic effect on bacterial biofilm growth in real time. The impedance measurements appear to combine both cellular growth and matrix production, representing a measurement of total biofilm mass. Several clinical and reference strains were tested, showing different slopes and cell index values which correlated with their capacity to form biofilms as assessed by attachment to standard microtitre well plates and safranin staining. Biofilms were heavily reduced in biofilm mutants or by protease treatment in protein-based biofilm matrixes. Antibiotic resistance patterns of biofilms, which were very different to those obtained by traditional methods like epsilon-tests on solid media, revealed features that would pass unnoticed by end-point methods. CONCLUSIONS: Once the biofilm is formed, antibiotic efficacy dramatically reduced and sub-inhibitory concentrations of some antibiotics, such as linezolid and clarithromycin, stimulated biofilm growth, stressing the importance of studying antibiotic resistance under biofilm growth conditions in real time. SIGNIFICANCE AND IMPACT OF THE STUDY: Real-time biofilm analysis provides a promising tool to evaluate antibiotic therapy in clinical biofilm-mediated infections.

[Conservative management of liver trauma and its complications: current gold-standard]. / Tratamiento conservador de los traumatismos hepáticos y sus complicaciones: gold-standard actual.

INTRODUCTION: The liver is the second most frequently involved organ in abdominal trauma in children. The aim of this study was to review the characteristics of liver traumas (LT) in children, its treatment and complications. MATERIAL AND METHODS: Retrospective study of patients with LT treated between 2010-2014. We analyzed data regarding diagnosis, conservative management (CM), complications and treatment. RESULTS: Twenty-four patients of LT with a mean age of 9.8 years (SD: 3.4) were treated at our center. Liver injury degrees according to the Organ Injury Scale of American Association for Surgery of Trauma (AAST) were: grade I (4), grade II (6), grade III (8), grade IV (5) and grade V (1). CT angiography was performed in 23 patients. Four of the six patients with initial hemodynamic instability required blood transfusion; of those, two required angioembolization for active bleeding in extrahepatic locations and a third required damage control surgery. Three patients presented late-onset complications: 2 large size bilomas which underwent spontaneous resolution and a third patient with a right biloma and section of the left bile duct who required a multidisciplinary approach. Median hospital stay was 6 days (r 1-92). With a mean follow-up of 17.75 months (SD: 16.35) (r: 2-57) long-term survival was 96%. The patient who received surgery died due to a post-traumatic brain injury. CONCLUSION: CM seems to be the treatment of choice in LT regardless of injury degree. Surgery should be reserved for cases refractory to CM due to the associated high mortality.

INTRODUCCION: El hígado es el segundo órgano más afectado en traumatismos abdominales en edad pediátrica. El objetivo de este trabajo es revisar las características de los traumatismos hepáticos (TH), su tratamiento y complicaciones. MATERIAL Y METODOS: Estudio retrospectivo de pacientes con TH atendidos entre 2010 -2014. Analizamos datos referentes al diagnóstico, tratamiento conservador (TC), complicaciones y tratamiento de las mismas. RESULTADOS: Se trataron 24 casos de TH con una edad media de 9,8 años (DS: 3,4). Los grados de lesiones hepáticas según la Organ Injury Scale of American Association for Surgery of Trauma (AAST) fueron: grado I (4), grado II (6), grado III (8), grado IV (5) y grado V (1). Se realizó angio-TC en 23 pacientes. Cuatro de los 6 pacientes que presentaron inestabilidad hemodinámica inicial requirieron transfusión de hemoderivados; de éstos, 2 requirieron angioembolización por sangrado activo extrahepático y un tercero se intervino de forma urgente. Tres pacientes presentaron complicaciones tardías: 2 bilomas de gran tamaño que se resolvieron espontáneamente y un biloma derecho con sección de vía biliar izquierda que requirió un abordaje multidisciplinar. En los 3 casos se trataba de traumatismos de alto grado (2 grado IV, 1 grado V). La mediana de estancia hospitalaria fue de 6 días (r: 1-92). Con una media de seguimiento de 17,75 meses (DS: 16,35) (r: 2-57) la supervivencia global fue del 96%. El paciente que requirió cirugía falleció por el traumatismo craneoencefálico asociado. CONCLUSIONES: El TC parece ser de primera elección en los TH independientemente del grado aunque no está exento de complicaciones. La cirugía debe reservarse para los casos refractarios al TC dada la alta mortalidad que conlleva.

[Exceptional causes of hematuria in childhood and infancy]. / Causas excepcionales de hematuria en la infancia y en la adolescencia.

INTRODUCTION: Hematuria is not uncommon in pediatric patients, even though it remains a diagnostic challenge in many cases. In this study we aim to draw attention to health professionals to have in mind rare diseases as a cause of hematuria. CASE REPORTS: We report 3 representative clinical cases of hematuria from very different origins: traumatic, congenital and infectious, illustrating the broad spectrum of causes of hematuria. COMMENTS: There are exceptional causes of hematuria which should be considered in clinical practice. The study of hematuria should always include a complete personal and familiar medical history, a careful physical examination and urine cultures. It is important to try to propose an algorithm study, avoiding unnecessary and invasive diagnostic tests that can be associated with complications.

INTRODUCCION: La hematuria es un signo frecuente en pediatría, siendo un reto diagnóstico en muchos casos. El objetivo de este trabajo es llamar la atención a los profesionales de la salud sobre la necesidad de tener presentes enfermedades infrecuentes como causa de hematuria. CASOS CLINICOS: Exponemos 3 tres casos clínicos representativos de formas de hematuria de orígenes muy distintos: traumático, congénito e infeccioso, que ilustran el amplio espectro de causas en la hematuria. COMENTARIOS: Existen causas de hematuria de presentación excepcional que debemos tener en cuenta en la práctica clínica. El estudio de la hematuria debe incluir siempre una completa anamnesis personal y familiar, una cuidada exploración física, análisis y cultivo de la orina. Es importante intentar proponer un algoritmo de estudio, evitando pruebas diagnósticas innecesarias e invasivas que no están exentas de complicaciones.

[Robotic pyeloplasty: first experiences]. / Pieloplastia robótica: primeras experiencias.

OBJECTIVE: To analyze our initial experience with the practice of robotic pyeloplasty and describe its advantages over laparoscopic and open surgery. PATIENTS AND METHODS: Retrospective study of the pediatric cases of pyeloplasty assisted by the robot da Vinci between March 2010 and May 2013. In all cases a transperitoneal approach was used with placement of 4 trocars (3 robotic trocars and 1 conventional laparoscopic). The technique used was the dismembered pyeloplasty Anderson-Hynes type. RESULTS: We operated 15 patients (12 men and 3 women) with a median age at surgery of 11 years (r: 5-18). The median weight was 40 kilos (r: 19-82). Five patients had a previous open pyeloplasty performed several years ago. All patients except but one were completed by robot. The only conversion to open surgery was performed because of difficulty in placing the double-J catheter due to a stenosis at the ureterovesical junction. They were no other intraoperative complications. The median operative time was 180 minutes (r: 110-252) and the median time for the robot docking 14 minutes (r: 4-50). The average hospital stay was 3.47 days (SD: 3). Mean follow-up was 16.97 months (SD: 10.24) and currently all patients are asymptomatic. CONCLUSIONS: Our initial experience seems to demonstrate that, coinciding with the literature, robotic pyeloplasty improves the results of laparoscopic pyeloplasty, retaining all its advantages and radically shortening the learning curve.

Relationship between bacterial load, morbidity and cagA gene in patients infected by Helicobacter pylori.

One hundred and seventy-six biopsies of the gastric corpus and antrum from 97 patients were processed using classical and molecular methods in order to study the relationship between the factor cagA of Helicobacter pylori, bacterial load and morbidity. Bacterial load in patients with cagA was greater than in patients without it, both in the antrum and corpus (p<0.01). There was a statistically significant association between cagA and consumption of proton pump inhibitors (adjusted odds ratio 3.11). Haemorrhage of the upper digestive tract was more associated with bacterial load than with the cagA gene (adjusted odds ratio 2.34 and 1.12, respectively), but none of these associations yielded statistical significance.

Activity of various drugs alone or in combination against Mycobacterium fortuitum.

Interest in Mycobacterium fortuitum has increased since it was recognized as an emergent pathogen. The objective of this study was to screen a large number of drug combinations in order to evaluate the activity of classical and new potentially useful antibiotics against M. fortuitum. Twenty M. fortuitum clinical isolates were studied with 51 combinations of two drugs and 47 combinations of three drugs belonging to different families: fluoroquinolones, linezolid, macrolides, rifamycins, aminoglycosides, and carbapenems. Activity was determined in Mueller Hinton broth by seeing whether the cultures were negative after 4 days of incubation with the combination of antibiotics. The most active drugs were moxifloxacin and gatifloxacin, which were active against 15 of the 20 strains studied, followed by amikacin (14 of the 20). The combinations of gatifloxacin with rifampicin or rifabutin, moxifloxacin with rifampicin or amikacin, and ciprofloxacin with amikacin were the most useful against M. fortuitum, as they showed activity in 18 of the 20 strains studied. Linezolid, imipenem, and ertapenem showed poor activity in this experimental model when they were used on their own. Larger studies, both in vitro and in vivo, should be done to confirm the true usefulness of the new fluoroquinolones, alone or in combination, in the treatment of M. fortuitum.

A possible novel Francisella genomic species isolated from blood and urine of a patient with severe illness.

Two identical isolates were recovered in pure culture from the blood and urine of a patient suffering from severe septicaemia associated with obstructive pyelonephritis secondary to lithotripsy. Preliminary phenotypic and genotypic characterizations based on serological, biochemical and sequence analyses following PCR amplification of selected gene regions indicate that this organism represents a potential new Francisella genomic species.

Real-time PCR with internal amplification control for detecting tuberculosis: method design and validation.

Real-time PCR has been a major development in the diagnosis of tuberculosis. However, most tests do not include an internal amplification control (IAC), which therefore limits it clinical application. In this study a new, easy to perform real-time PCR test with IAC was designed and validated in clinical samples. The primers amplified a 163-bp fragment of IS6110 of Mycobacterium tuberculosis and the IAC was designed with a fragment of a different microorganism (Chlamydia trachomatis). The interassay and intraassay variation of this test were very low (0.45-1.65% and 0.18-1.80%, respectively). The detection accuracy was validated in 50 samples (25 urine, 25 sputum) with different concentrations of M. tuberculosis, 18 clinical isolates of non-tuberculous mycobacteria and 148 samples with clinical suspicion of pulmonary tuberculosis. The specificity was 100%. The detection limit of this PCR test without IAC was approximately 15 bacteria and with IAC approximately 32 bacteria. This real-time PCR with IAC assay can improve the detection of M. tuberculosis and contribute to standardization of this diagnostic technique.

[Resistant mutant prevention concentration of fluoroquinolones in clinical isolates of extended spectrum beta-lactamase (ESBL) producing and non-producing strains of Escherichia coli]. / Determinación de la concentración preventiva de mutantes resistentes a fluoroquinolonas en aislamientos clínicos de Escherichia coli productoras y no productoras de betalactamasas de espectro extendido.

The aim of this job is to study the capacity of ciprofloxacin and levofloxacin in restricting the development of resistant mutants in strains of Escherichia coli by determining the mutant prevention concentration (MPC). Ninety-nine isolates of E. coli with different fluoroquinolone susceptibilities were studied and divided into ESBL-producing (n = 60) and non-ESBL producing (n = 36) groups. MPC values were determined using an inoculum of 1010 cfu/ml on Mueller-Hinton plates with serial dilutions of the antibiotics. No significative differences were detected in MIC of ESBL-producing and non-ESBL producing strains of E. coli. Ciprofloxacin susceptible ESBL-producing strains exhibit higher MPC for ciprofloxacin and levofloxacin than non-ESBL producing strains. Our study helps to explain the frequent fluoroquinolone resistance found in ESBL-producing strains. In this context, doubts emerge about the advisability of using fluoroquinolones to treat infections caused by ESBL-producing strains.

[Rehbein's procedure versus De la Torre in Hirschsprung's disease]. / Rehbein versus De la Torre en la enfermedad de Hirschsprung.

The authors perform a retrospective study with a 4 years follow up of 46 patients operated of Hirschsprung's disease (HD). In 36 cases by with staplers Rehbein technique (TR) and in 10 others with De la Torre endorectal pull-through (TEPT). In all them diagnosis was achieved by mean of radiology, manometry, and hystochemical procedures. During the surgical procedure was performed in all cases biopsies to confirm the neuronal integrity of the colon descended. In the TR group, 16.6% of patients presented rectal achalasia with constipation due to 3 cms. aganglionic rectum remnant, while in the TEPT group this circumstance are not presented because all aganglionic rectum was eliminated. Otherwise TEPT technique permits an earlier application, diminuend the hospitalization time,shortening the start of feeding and with a good cosmetic result. None of this patients presented infection, stenosis, bleeding or incontinence.

Screening for sterilizing activity of antibiotic combinations in an acid model of rapidly growing mycobacteria during the stationary phase of growth.

BACKGROUND: In view of the problems of correlation between the data provided by classical microbiological studies and clinical response, we designed an in vitro method to screen for the sterilizing activity of various antibiotics, individually or in combinations, against clinical isolates of various rapidly growing mycobacteria in the stationary phase. MATERIAL AND METHODS: We screened a large number of antibiotic combinations (4-16 microg/ml) for their sterilizing capacity in 26 Mycobacterium fortuitum clinical isolates, 7 Mycobacterium chelonae and 2 Mycobacterium abscessus clinical isolates (10(5) CFU). RESULTS: The best results against M. fortuitum were obtained with moxifloxacin, both on its own (13/26 strains) and in combination. This drug is also very active against M. chelonae (3/7 strains), and in combination with clarithromycin and amikacin exhibits sterilizing activity against all the strains studied. Combinations of clarithromycin with moxifloxacin or linezolid at high doses (16 microg/ml) exhibit activity against M. abscessus. CONCLUSIONS: The most relevant finding of our study is the good activity of moxifloxacin against these microorganisms in the stationary phase. This indicates the need to confirm these data in animal models or clinical trials in order to determine their true clinical importance.

[In vitro generation of mutants of Klebsiella pneumoniae following exposure to fluorquinolones. Relationship with the presence of extended spectrum betalactamases]. / Generación in vitro de mutantes de Klebsiella pneumoniae tras exposición a fluoroquinolonas. Relación con la presencia de betalactamasas de espectro extendido.

In order to provide data that may help to explain the relationship between production of extended spectrum betalactamases and fluorquinolone resistance in Klebsiella pneumoniae, we have developed an in vitro model of exposure to sub-inhibitory concentrations of various fluorquinolones (ciprofloxacin, levofloxacin and moxifloxacin) in two strains, one of which is a producer of extended spectrum betalactamases (ESBL). Our data show that mutants with reduced fluorquinolone susceptibility appear in both cases, but that they appear earlier in ESBL-producing strains (13.3 days versus 14.4 days), especially following exposure to ciprofloxacin (12.5 days versus 14.9 days for levofloxacin and 14.2 days for moxifloxacin). Therefore, our data help explain the greater fluorquinolone resistance in ESBL-producing strains and confirm the need to administer the correct doses of fluoroquinolones, especially in the case of ciprofloxacin, in order to prevent the emergence of resistant mutants. This is particularly important if the strain is an ESBL-producer.

In vitro bactericidal activity of antibiotic combinations against clinical isolates of Mycobacterium chelonae.

Mycobacterium chelonae is one of the most antibiotic-resistant species of the pathogenic, rapidly-growing mycobacteria. The objective of this study was to evaluate the bactericidal activity of classical and new potential drugs, alone and in combinations, against clinical isolates of Mycobacterium chelonae. Clarithromycin was seen to be the most bactericidal drug. In drug combinations, this compound is most useful with gentamicin, fluoroquinolones, rifampicin, linezolid, other aminoglycosides, doxycyline and carbapenems. The combination of tobramycin with ciprofloxacin or moxifloxacin also exhibits similar activity. In conclusion, this study on bactericidal activity of drug combinations against Mycobacterium chelonae confirms the utility of clarithromycin associated with other drugs, and, of the new drugs, the value of moxifloxacin and linezolid.