Detección rápida de Enterobacterias productoras de carbapenemasas en hisopados rectales de pacientes neonatos colonizados / Rapid detection of carbapenemase-producing Enterobacteriaceae in rectal swabs of colonized neonatal patients

Resumen Objetivo: Detectar la presencia de Enterobacterias productoras de carbapenemasas en hisopados rectales de neonatos mediante técnica de nefelometría láser y caracterización del tipo de carbapenemasa mediante test inmunocromatográfico. Materiales y Métodos: Estudio descriptivo de corte transversal. Fueron incluidos 57 neonatos, tamizados al ingreso a UCI, mediante hisopado rectal, procesado por nefelometría laser HB&L Carbapenemase (Alifax®) y caracterización del tipo de carbapenemasa por inmunocromatografía rápida RESIST-3 (Coris BioConcept®). Resultados: Encontramos un alto porcentaje de colonización rectal (22.9%) correspondiente a 13 hisopados positivos y 44 (77.1%) fueron negativos por nefelometría láser. Por VITEK 2® se obtuvo identificación de Klebsiella pneumoniae resistente a carbapenémicos en los 13 aislamientos y el test inmunocromatográfico reveló la presencia de carbapenemasas blaKPC en estos aislamientos. Discusión: Estudios evidencian el aumento de la colonización por microorganismos productores de carbapenemasas en neonatos. Los resultados de este estudio demuestran que un porcentaje significativo de neonatos que ingresan a las Unidades de Cuidado Neonatal se encuentran colonizados con Enterobacterias productoras de carbapenemasas en tracto intestinal. Lo anterior constituye un riesgo potencial para su diseminación y posterior desarrollo de brotes, en donde surge la importancia de implementar estrategias de vigilancia activa como la tamización rectal para la detección oportuna de neonatos colonizados.

Abstract Objective: To detect the presence of carbapenemase-producing Enterobacteriaceae in rectal swabs of neonates by means of laser nephelometry technique and characterization of the type of carbapenemase by immunochromatographic test. Materials and Methods: Descriptive cross-sectional study. 57 neonatal patients were included; They underwent rectal screening upon admission to the ICU, using swabs which were processed by HB&L Carbapenemase laser nephelometry (Alifax®) and characterization of the type of carbapenemase by RESIST-3 rapid immu nochromatography (Coris BioConcept®). Results: We found a high percentage of rectal colonization (22.9%) corresponding to 13 positive swabs and 44 samples (77.1%) were negative by laser nephelome try. Identification of carbapenem-resistant Klebsiella pneumoniae was obtained by VITEK 2® in the 13 isolates and the immunochromatographic test revealed the presence of blaKPC carbapenemases in these isolates. Discussion: Studies show increased colonization by carbapenemase-producing microorganisms in neonates. The results of this study demonstrate that a significant percentage of neonates who enter Neonatal Care Units are colonized with Enterobacteriaceae that produce carbapenemases in the intestinal tract. This constitu tes a potential risk for its spread and subsequent development of outbreaks, where the importance of implementing active surveillance strategies such as rectal screening for the timely detection of colonized neonates arises.

Colonización vaginal/rectal por Streptococcus agalactiae en gestantes de Melena del Sur, Cuba / Vaginal and rectal Streptococcus agalactiae colonization in pregnant women from Melena del Sur municipality in Cuba

Introducción: en Cuba se desconoce el peso de la colonización vaginal o rectal por Streptococcus agalactiae o estreptococo ß-hemolítico grupo B (SGB) como factor de riesgo para el desarrollo de sepsis neonatal precoz. Objetivo: determinar la prevalencia de colonización vaginal/rectal por SGB entre la población de gestantes del municipio Melena del Sur, Mayabeque. Métodos: se realizó un estudio observacional de corte transversal entre febrero-agosto 2011, en el que se incluyeron 120 gestantes (35-37 semanas). Se obtuvieron muestras vaginales y rectales que se cultivaron en caldo Todd Hewitt y medio Granada y se calculó la sensibilidad y especificidad de ambos medios de cultivo para la recuperación de SGB. Se hizo seguimiento de las embarazadas hasta el momento del parto para conocer acerca de la aparición de factores de riesgo para el desarrollo de sepsis neonatal, sobre la imposición de profilaxis antibiótica intraparto y si se produjeron casos de sepsis neonatal (tipo y evolución). Resultados: la especificidad lograda con el medio Granada para el aislamiento de SGB fue superior (94,57 %) pero la sensibilidad fue de solo 60,71 %; la combinación de su empleo y el caldo Todd Hewitt permitió la demostración de colonización por SGB en el 27,5 % de las gestantes. Se constató la administración de tratamiento profiláctico a las embarazas colonizadas en las que se presentaron factores de riesgo en el momento del parto y se produjeron solo cuatro casos de sepsis neonatales, lo que realza el valor de esta estrategia en la intercepción de la transmisión vertical.

Introduction: the impact of vaginal or rectal colonization by Streptococcus agalactiae or group B hemolytic streptococcus as risk factor for the development of early neonatal sepsis is still unknown in Cuba. Objective: to determine the prevalence of group B hemolytic streptococcus colonization of the vagina and the rectum among the pregnant women of the Melena del Sur municipality in Mayabeque province, Cuba. Methods: observational and cross-sectional study conducted from February to August 2011, which covered 120 pregnant women (35 to 37 weeks of gestation). Vaginal and rectal samples were taken to be cultured in ToodHewitt broth and grenade medium and the sensitivity and specificity of both culturing media were then calculated for recovery of Group B hemolytic streptococcus. The pregnant women were followed-up up to the delivery time so as to learn about the occurrence of risk factors for developing neonatal sepsis, the application of antibiotic prophylaxis intrapartum and the occurrence of cases of neonatal sepsis (type and progress). Results: the specificity of the grenade medium for Group B streptococcus was higher (94.57 %), but sensitivity was just 60.71 %. The combination of grenade medium plus Todd Hewitt broth allowed showing the Group B hemolytic streptococcus colonization in 27.5 % of pregnant women. It was then confirmed that prophylactic treatment was given to colonized pregnant women who presented with risk factors at the time of delivery and that there were just four neonatal sepsis cases, which stressed the value of this strategy in halting the vertical transmission.

Colonization Rate, Risk Factor for Acquisition and Genetic Diversity of Vancomycin-Resistant Enterococci (VRE) Isolated from Rectal Culture of Patients in Intensvie Care Units from Ten Large Hospitals in Korea / 감염

BACKGROUND: VRE have become an emerging nosocomial pathogen in Korea, but there has not been nationwide study on the colonization of VRE among high risk groups of hospitalized patients. The purpose of this study was to determine the prevalence of rectal colonization of VRE among patients hospitalized in the intensive care unit (ICU), to study the risk factors for nosocomial acquisition of VRE among those patients, to define the genetic diversity of VRE strains in major hospitals in Korea. METHODS: Between January the 20th and 30th of 2000, a point surveillance study was conducted in the ICU of the ten large hospitals, which were located nationwide. Surveillance rectal swab cultures for detecting VRE were obtained among 214 patients admitted to the ICU during the study period. To isolate VRE, rectal swab cultures were performed on Enterococcosel(R) agar that containing 6 microgram/mL of vancomycin. Minimal inhibitory concentrations (MICs) of vancomycin and teicoplanin were determined by agar dilution method. For the genotyping of VRE isolates, the detection of vanA, vanB, vanC1 and vanC2 gene by polymerase chain reaction was done. Pulsed-field gel electrophoreis (PFGE) was used for elucidating the genetic relatedness of VRE isolates. To identify the risk factors for rectal VRE colonization, patients harboring VRE were compared to patients who were not colonized with this organism. RESULTS: The rectal colonization rate of VRE was variable from 9.7% to 51.9% according to hospital. 64 VRE strains which were isolated from 63 patients included 37 E. feacium. 26 E. gallinarum and 1 E. casseliflavus isolates. Therefore the colonization rate of clinically significant vanA type VRE was 17.3% (37/ 214). 37 E. feacium. 26 E. gallinarum and 1 E. casseliflavus isolates were presented as vanA, vanC1 and vanC2 genotypes, respectively. Risk factors for rectal VRE colonization included the presence of chronic illness, previous use of broad spectrum antibioitcs es-pecillay vancomycin, and prolonged stay in ICU. Various PFGE patterns are noted among vanA type VRE isolates, so individual acquisition of VRE during stay in the majority of ICUs were suggested. But there is some evidence of focal VRE spread within the ICU and between hospitals. CONCLUSION: This study demonstrated the high rectal colonization rate (17.3%) of clinically significant vanA type VRE among patients admitted to the ICUs of ten large hospitals located nation-widely. This study suggested that practicing HICPAC guidelines, restricted vancomycin usage and periodic surveillance cultures in patients with high risk factors are important in preventing the emergence and spread of VRE infection among ICU patients.

Rectal Surveillance Culture of Vancomycin-resistant Enterococci (VRE) Colonization among Patients Hospitalized in the Intensive Care Unit (ICU) / 감염

BACKGROUND: VRE (vancomycin-resistant enterococci) have been an important nosocomial pathogen in the United States in the 1990s. VRE are usually multidrug-resistant and currently there is no effective antimicrobial agent for the treatment of such organisms. Recently, VRE have become an emerging nosocomial pathogen in Korea, but there have been few studies on the epidemiologic investigation of the infection or colonization of VRE among hospitalized patients with high risk factors. The purpose of this study was to determine the prevalence of rectal colonization of VRE among patients hospitalized in the intensive care unit (ICU), to study the risk factors for nosocomial acquisition of VRE, and to obtain the baseline data for controlling the spread of VRE infection within the hospital. METHODS: Between August 1 and October 12 (10 weeks) 1998, a prospective surveillance study was conducted in the ICU at Korea University, Guro Hospital. Surveillance rectal swab cultures for detecting VRE were obtained at weekly intervals among 93 patients admitted to the ICU during the study period. To obtain the VRE, rectal swab cultures were performed on Enterococcosel agar (BBL Microbiology Systems, Cockeysville, Md., USA) containing 6 microgram/mL of vancomycin. Minimal inhibitory concentrations (MICs) of vancomycin and teicoplanin were determined by agar dilution method. For the genotyping of isolated VRE, detection of vanA, vanB, vanC1 and vanC2 gene by polymerase chain reaction was done. Patients harboring VRE were compared to patients who were not colonized with this organism to identify the risk factors associated with rectal colonization. RESULTS: The rectal colonization rate of VRE was 23.7% (22/93 patients), but no patients had VRE infection during the study period. Twenty-six strains of VRE, which were isolated from 22 patients, included 2 E. faecium, 18 E. gallinarum and 6 E. casseliflavus isolates. Two vancomycin-resistant E. faecium (VREF) isolates were vanA genotype. All E. gallinarum, and all E. casseliflavus isolates demonstrated vanC1 and vanC2 genotype, respectively. Risk factors for rectal colonization of VRE included diabetes, catheterization of arterial and central venous lines, and vancomycin usage. CONCLUSION: This study demonstrated the low rectal colonization rate of clinically significant VREF (2.2%:2/93 patients) isolates among patients admitted to the ICU. This study suggests that maintaining HICPAC guidelines, restricted vancomycin usage and periodic surveillance in patients with high risk factors are important in preventing the emergence and spread of VRE infection among ICU patients in a university- affiliated hospital.