[Necrotizing fasciitis and group A streptococcal toxic shock syndrome in two patients without risk factors]. / Fascitis necrotizante y choque tóxico en infección por estreptococo grupo A.

Necrotizing fasciitis associated to group A streptococcus (S. pyogenes) infection is a deep-seated infection of the subcutaneous tissue that results in progressive destruction of fascia and fat, with a high mortality rate due to a rapid progression of the illness to shock and multiple organ dysfunction. The challenge is to perform a prompt diagnosis because it is often confused with a minor soft-tissue infection. This infection should be aggressively treated with systemic antimicrobials, surgical debridement, and critical care. We present two cases of necrotizing fasciitis associated to infection with Streptococcus pyogenes patients developed myonecrosis and toxic shock syndrome within the following 24 hours after admission. In addition, we reviewed the pathogenic mechanism, diagnosis and treatment of this syndrome and discuss published treatment recommendations.

[Catheter-associated bloodstream infections. Review of five-year surveillance among hospitalized patients]. / Bacteriemia asociada con catéter venoso central. Revisión de cinco años de vigilancia en pacientes hospitalizados.

BACKGROUND: Catheter related infections (CRI) and bloodstream infection (BSI) associated to central venous catheter (CVC) is cause of frequent hospital-acquired infection (HAI) and a major reason of morbidity and mortality among patients and it is itself an indicator of quality health care. OBJECTIVE: To determine the incidence of CRI and BSI and to identify the hospital areas where they occurred over a five-year period. METHODS: A prospective study from 2004 to 2008 in a population of hospitalized patients who required the use of CVC was made. The HAI team detected the appearance of CRI during a daily routine surveillance. RESULTS: During the period of observation, 176 BSI were detected, accounting for 11 % of all HAI, and represented the third place in frequency. Incidence rate for 1000 catheter-days varied from 2.7 in 2006 to 5.4 in 2008; 57 % of these BSI were detected in the intensive care units. Candida spp. accounted as the more frequently isolated microorganism with predominance of C. parapsilosis. CONCLUSIONS: Our results and the incidence rate found in our study occurred within rates established in other studies.

MGIT and other methods for diagnosing tuberculosis in a private hospital system with low incidence / MGIT y otros métodos para diagnosticar tuberculosis en un sistema hospitalario privado con baja incidencia

Background: Tuberculosis (TB) is still a threat to public health; in 2014 caused 1.5 million deaths worldwide; in hospitals where the prevalence of TB is low, it is appropriate to evaluate the effectiveness of tests to diagnose it. Methods: We reviewed reports of airway clinical specimens sent for studies of tuberculosis to the microbiology laboratory from Tec Salud System private hospitals (400 beds) in the metropolitan area of ​​Monterrey, NL, from May 2012 to December 2015. In conjunction with Ziehl-Neelsen (ZN) stain, and solid Lowenstein-Jensen medium (LJ), our laboratory resources also include fluorescent LED microscopy (Carl Zeiss Microscopy Products), MGIT 320 (Mycobacteria Growth Indicator Tube liquid culture detection system, Becton Dickinson), and recently incorporated a real-time PCR system the Xpert MTB/RIF test (Cepheid, Sunnyvale, CA). Results: In 731 respiratory specimens from 510 patients, M. tuberculosis was isolated from 78 samples belonging to 50 patients on LJ and MGIT LJ 42 (84%) and MGIT 49, (98%) of the samples. From 41 patients identified, 26 (63.4%) were positive to fluorescein, and 25 (60.9%) with Ziehl-Neelsen stain. Real time PCR (Xpert TB) was positive in 13 out of 17 patient-airway samples (76.4%). Conclusions: Usefulness of liquid culture (MGIT) and solid culture (LJ) is shown; the first can significantly cut incubation times.

Introducción: la tuberculosis (TB) aún es una amenaza para la salud pública; en 2014 causó 1.5 millones de muertes a nivel mundial. En hospitales donde la prevalencia de TB es baja, resulta conveniente evaluar la efectividad de las pruebas para diagnosticarla. Métodos: revisamos los informes de resultados de muestras de vías respiratorias enviadas para estudios de tuberculosis de mayo de 2012 a diciembre de 2015 al laboratorio de Microbiología del Sistema Tec Salud (400 camas) en el área metropolitana de Monterrey. Además de la tinción de Ziehl-Neelsen (ZN) y cultivo sólido de Lowenstein-Jensen (LJ); se realizó fluorescencia LED, cultivo en medio líquido MGIT 320 y más recientemente el Xpert MTB/RIF test. Resultados: se cultivaron en LJ y MGIT 731 muestras de vías respiratorias de 510 pacientes; en las muestras de 50 de ellos se identificó M. tuberculosis, 49 en MGIT (98%) y 42 en LJ (84%). De las muestras correspondientes a 41 pacientes, 26 (63.4%) fueron positivas con fluoresceína, y 25 (60.9%) con ZN. En las muestras de 17 pacientes se hizo PCR en tiempo real (Xpert MTB), 13 fueron positivas (76.4%). Conclusiones: se demuestra la utilidad del cultivo en medio liquido (MGIT) y del LJ en medio sólido; el primero, además de ser más sensible, permite acortar en forma importante los tiempos de incubación.

[Role of anaerobic blood culture in the simultaneous blood culture taking for the diagnosis of bacteremia]. / Papel del hemocultivo anaeróbico en la toma simultánea de hemocultivos para el diagnóstico de bacteriemia.

BACKGROUND: Harboring a high mortality, the incidence of sepsis is increasing; thus detection, identification and susceptibility tests of the involved microorganisms become urgent. METHODS: We reviewed the records from January 2013 until July 2014 of a total of 4110 blood culture bottles taken from adult patients in a private tertiary hospital. RESULTS: Growth of microorganisms was observed in 559 bottles (12.6%). We emphasize that 2648 blood cultures (60%) were taken in two paired aerobic and anaerobic bottles drawn at the same time (1324 pairs); from these, growth was observed in 182 inoculated bottles drawn from two different sites at the same time from 135 patients (13.7%). In 86 pairs of bottles with samples from 54 patients (40%), growth occurred only in the aerobic blood culture bottles. Also, growth of microorganisms was observed only in anaerobic bottles in 24 pairs (13.19%), corresponding to 21 patients (15.5%, p<0.05%). In blood cultures from 32 out of 60 patients with growth in both media (53%), microbial growth was detected first in the anaerobic bottle. CONCLUSIONS: The usefulness of blood cultures for anaerobes for the identification of obligate anaerobic bacteremia which rarely occur is low (2.2% of patients with bacteremia); however, in 15.55% of the patients the risk of completely overlook bacteremia was present, and in 53% of patients with positive cultures, bacteremia was established earlier, and thus permitted earlier and accurate decision making.

Introducción: la frecuencia de la septicemia va en aumento y su mortalidad es alta; por lo tanto, su detección, la identificación del microorganismo causal y su susceptibilidad son perentorias. Metodos: se revisaron los registros de 4110 botellas de cultivo de sangre obtenida de enero de 2013 a julio de 2014 de pacientes adultos en un hospital privado de tercer nivel. Resultados: se observó crecimiento de microorganismos en 559 cultivos (12.6 %). En 2648 hemocultivos (60 %) inoculados en pares de frascos uno con medio aeróbico y el otro anaeróbico (1324 sets), se detectó crecimiento en 182 frascos a los que les fueron inoculadas las muestras tomadas al mismo tiempo a 135 pacientes (13.7 %). En 86 pares de frascos con las muestras de 54 pacientes (40 %), el crecimiento solamente se dio en el frasco aeróbico (47.5 %); en 24 pares de frascos (13.19 %) tomados a 21 pacientes (15.5 %, p < 0.05), solamente hubo crecimiento en el frasco anaeróbico. En los hemocultivos de 32 de 60 pacientes con crecimiento en ambos frascos (53 %), el crecimiento se detectó primero en el frasco anaeróbico. Conclusiones: los hemocultivos anaeróbicos tienen una utilidad baja para la detección de bacteriemias por anaerobios estrictos; no obstante, en el 15.55 % de los pacientes estuvo presente el riesgo de pasar por alto la presencia de bacteriemia, y en 53 % de los pacientes con hemocultivos positivos, el diagnóstico de bacteriemia pudo establecerse de manera más temprana, lo que permitió anticipar con mejor precisión la toma de decisiones.

[Necrotizing fasciitis, myositis, arthritis, and streptococcal toxic shock syndrome caused by group G Streptococcus. Report of one case]. / Fascitis necrotizante, miositis y síndrome de choque tóxico secundario a estreptococo del grupo G. Reporte de un caso.

BACKGROUND: Necrotizing fasciitis (NF), myositis, and streptococcal toxic shock syndrome (STSS) associated with group G ß-hemolytic streptococcus (GGS) occasionally coincide. CLINICAL CASE: We describe a case of GGS simultaneously occurring with NF, myositis, arthritis, and STSS in an 83-year-old woman with sequelae of cerebrovascular disease, hospitalized after two days of fever and with a painful swollen left foot. She was hypotensive, her foot had purplish discoloration, which showed blisters spreading to the lower third of the leg, and no crepitus was present. Fluid, vasopressive support, tigecyclin, and clindamycin were used. Debrided tissue and fluid aspirated from the knee joint revealed Gram-positive cocci. The patient developed renal and respiratory failure on the fifth day, requiring support. She underwent amputation above the knee of the left leg, after which her condition improved. She was discharged one month later. CONCLUSION: GGS can cause life-threatening infections such as NF, myositis, and/or STSS. GGS usually afflicts aging patients with comorbid states, and occasionally healthy subjects.

Introducción: ocasionalmente concurren la fascitis necrotizante (FN), con miositis, y síndrome de choque tóxico post-estreptocócico (SSTE) asociados con infección por estreptococo ß-hemolítico del grupo G (EGG). Caso clínico: presentamos un caso de infección en el que concurren simultáneamente FN, miositis, artritis y SSTE en una mujer de 83 años con secuelas de enfermedad cerebrovascular, hospitalizada tras dos días de fiebre y dolor, así como hinchazón del pie izquierdo. Se encontraba hipotensa y el pie mostraba coloración púrpura con flictenas que se extendían hacia el tercio inferior de la pierna; no había crepitación a la presión digital. Se empleó hidratación parenteral, vasopresores, tigeciclina y clindamicina. Tanto el tejido desbridado como el líquido aspirado de la articulación de la rodilla revelaron cocos gram positivos. Al quinto día la paciente desarrolló falla renal y respiratoria que requirieron de apoyo. La paciente fue sometida a amputación supracondílea de la pierna izquierda; después de eso, su condición mejoró. Un mes después fue dada de alta. Conclusiones: el EGG puede causar infecciones potencialmente mortales, como FN, miositis, y/o SSTE. El EGG por lo general afecta a pacientes ancianos con estados comórbidos y ocasionalmente a sujetos sanos.