Aura Lucía Leal

Nosocomial infections caused by community-associated methicillin-resistant Staphylococcus aureus in Colombia.

BACKGROUND Community-associated methicillin-resistant Staphylococcus aureus strains (CA-MRSA) have emerged as the causative agent of health care-associated infections. METHODS An observational and prospective study was carried out in 5 hospitals in Bogotá, Colombia; severe MRSA infections were identified, and their origin led to classification as health care-associated (HA-MRSA), community-associated, or nosocomial infections. MRSA isolates were analyzed by SCCmec, pulsed-field gel electrophoresis, multilocus sequence typing, and virulence factors. RESULTS Twenty-six (10.4%) CA-MRSA nosocomial infection-causing strains (eg, USA300) were detected in 250 MRSA infection isolates in mainly primary bacteremia and surgical site infections. The mortality related to nosocomial infection by CA-MRSA was 27%. CONCLUSION The presence of nosocomial infection by CA-MRSA in Colombia was confirmed.

Fungal bloodstream infections in tertiary care hospitals in Colombia

BACKGROUND Fungal infections have increased in critical care patients, causing high morbidity and mortality. AIMS Describe the frequency and responsible fungal species involved in bloodstream fungal infection from 2001 to 2007 in tertiary care level hospitals belonging to a surveillance network in Colombian cities. METHODS Data were collected from a microbiology surveillance network based on 27 hospital laboratories in five Colombian cities. Data were entered into a Whonet® version 5.4 database. Fungemia data were analyzed according to location (Intensive care unit -ICU- vs. non-ICU services). Frequency over time was also described. RESULTS Fungal infections corresponded to 4.1% of all bloodstream infections. Candidemia represented 3.7% and 5.2% of all isolates in non-ICU and ICU services, respectively. Over 99% of the isolates were yeasts, and Candida albicans was the most frequently isolated organism in and out of the ICU, showing a decreasing trend in the last few years. In the adult ICU and non-ICU services, the second organism most frequently isolated was C. tropicalis, while C. parapsilopsis was the most frequent in the pediatric and neonatal ICU, also showing an overall decreasing trend. Cryptococcus neoformans was the fourth mycotic organism most frequently identified. CONCLUSIONS In Colombia, epidemiology of fungal infections seems to be changing. C. albicans is the principal agent causing bloodstream fungal infection, but an increase of non-albicans species has been observed as well as high frequency of C. neoformans.

Canales Endémicos y Marcadores de Resistencia Bacteriana, en Instituciones de Tercer nivel de Bogota, Colombia

Objetivo Determinar los perfiles de resistencia bacteriana y los canales endemicos en 14 instituciones de tercer nivel. Metodos Poblacion. Bogota-Colombia, 14 hospitales pertenecientes al Grupo para el Control de la Resistencia Bacteriana de Bogota (GREBO). A partir de la informacion obtenida de los laboratorios de microbiologia de los centros participantes (metodos automatizados y manuales), se creo una base de datos usando los programas BacLink 2.0 y Whonet 5.3, durante los anos 2001, 2002 y 2003. Los perfiles de susceptibilidad fueron hallados acordes a las normas de la nCCLS (2003). Se realizo un analisis descriptivo de los diferentes marcadores de resistencia y se determino el canal endemico de la resistencia para los hospitales, utilizando los puntos entre los percentiles 25 y 75 %, para cada mes durante el periodo de estudio. Resultados Se analizaron 84664 aislamientos. Los mas frecuentes fueron Escherichia coli, Staphylococcus aureus, Staphylococcus coagulasa negativo, Klebsiella pneumoniae y Pseudomonas aeruginosa. La resistencia para los anos 2001, 2002 y 2003 fue respectivamente: S. aureus meticilino resistente: 41 %, 48 %, 48 %; Staphylococcus coagulasa negativo resistente a oxacilina: 75 %, 73 %, 72 %; E. faecium vancomicina resistente: 14 %, 9 %, 3 %; K. pneumoniae resistente a cefalosporinas de tercera generacion: 37 %, 25 %, 23 %; P. aeruginosa resistente a imipenem: 24 %, 22 %, 17 %; P. aeruginosa resistente a ciprofloxacina: 46 %, 46 %, 35 %, A. baumannii resistente a imipenem: 11 %, 29 %, 39 %. Los canales endemicos evidenciaron la problematica de la resistencia bacteriana, esta se centro en la presencia de S. aureus meticilino resistente y en el marcado incremento de la resistencia de A. baumanni a imipenem. Conclusiones Se destacan los altos porcentajes de resistencia para todos los marcadores de impacto epidemiologico a nivel hospitalario especialmente en Unidades de Cuidado Intensivo.

Resistencia Antimicrobiana en Unidades de Cuidado Intensivo de Bogotá, Colombia, 2001-2003

Objetivos Determinar la resistencia antimicrobiana entre los aislamientos bacterianos identificados en pacientes hospitalizados en Unidades de Cuidado Intensivo. Metodos Se recolecto la informacion de los aislamientos de microbiologia provenientes de las Unidades de Cuidado Intensivo (UCI) de 14 instituciones de tercer nivel, pertenecientes al Grupo para el Control de la Resistencia Bacteriana de Bogota (GREBO), entre los anos 2001 y 2003. Se obtuvieron 27301 aislamientos y su perfil de susceptibilidad fue analizado por el programa Whonet 5.3. Resultados Los microorganismos aislados con mayor frecuencia fueron Staphylococcus aureus, Escherichia coli, Staphylococci coagulasa negativo (SCN), Pseudomonas aeruginosa y Klebsiella pneumoniae. Las tasas de resistencia de S. aureus y de SCN a oxacilina del 2001 al 2003 oscilaron entre 61 y 63 % y entre 78 y 83 %, respectivamente. La resistencia a cefalosporinas de tercera generacion en E. coli fue cercana a 10 % y a ciprofloxacina fue superior a 20 %. La resistencia a cefalosporinas de tercera generacion de K. pneumoniae fue superior a 30 % durante el 2001. La resistencia de P. aeruginosa a varios grupos de antibioticos supero 30 % y la frecuencia de cepas multirresistentes oscilo entre 16 y 24 %. Conclusion Las tasas de resistencia encontradas son superiores a las mostradas por estudios de vigilancia en E.E.U.U., Europa y otras ciudades de America Latina.

Emergencia de fenotipos resistentes a cefalosporinas de tercera generación en Enterobacteriaceae causantes de infección del tracto urinario de inicio comunitario en hospitales de Colombia

INTRODUCTION Urinary tract infection (UTI) is a common disease in the community, and a matter of concern due to the increasing resistance of microorganisms to first line antibiotics and the emergence of multiresistant strains producing extended spectrum beta lactamases (ESBL) in the community. METHODS An analytical case-control study was conducted over twelve months in 9 hospitals in Colombia. We collected isolates of E. coli, Klebsiella spp. and Proteus spp. from patients with community-onset UTI. The presence of ESBL, AmpC and KPC beta-lactamases were characterized by microbiological and molecular methods. The aim of this study was to determine factors related to the presence of these mechanisms of the resistance to third generation cephalosporins. RESULTS A total of 325 isolates (287 E. coli, 29 Klebsiella spp. and 9 Proteus spp.) were included. The most frequent comorbidities among the patients were hypertension (n=82; 25.2%) and diabetes mellitus (n=68; 20.9%). Previous use of antimicrobials was found in 23% of patients, and 29% had a previous UTI. Resistance to third and fourth generation cephalosporins varied between 3.4% and 6.3% in E. coli and between 6.9% and 17.8% in K. pneumoniae. Seven (2.4%) CTX-M-15 ESBL-producing E. coli isolates were detected; four of them belonged to ST 131 clone. In K. pneumoniae we detected three KPC-3 carbapenemases (10.3%). CONCLUSIONS This study confirms the emergence of resistance to third generation cephalosporins enterobacteriaceae as a cause of community-onset UTI. We emphasize the presence of ST 131 clone and KPC carbapenemases circulating in Colombia outside the hospital environment.

Molecular epidemiology and characterization of virulence genes of community-acquired and hospital-acquired methicillin-resistant Staphylococcus aureus isolates in Colombia

OBJECTIVE To determine the molecular epidemiology and presence of virulence genes in community-acquired (CA) and hospital-acquired (HA) methicillin-resistant Staphylococcus aureus (MRSA) isolates and their relationship to clinical outcomes. METHODS An observational and prospective study of infections caused by MRSA was conducted between June 2006 and December 2007 across seven hospitals in three Colombian cities. MRSA isolates were analyzed for SCCmec. Also, pulsed-field gel electrophoresis and multilocus sequence typing were performed and 25 virulence genes were identified. RESULTS Two hundred and seventy isolates were collected from 262 adult hospital patients with MRSA infections. Overall, 68% of the isolates were classified as HA-MRSA and 32% as CA-MRSA. We identified differences in the patterns of virulence genes: 85% of HA-MRSA isolates possessed the enterotoxin gene cluster (egc), whereas 92% of CA-MRSA isolates possessed the lukF-PV/lukS-PV genes. Multivariate analysis showed an increased risk of mortality for seg (p=0.001, odds ratio 4.73) and a protective effect for eta (p=0.018, odds ratio 0.33). CONCLUSIONS Our study confirms that three clones of MRSA predominantly circulate in Colombia: a Chilean clone, a pediatric clone that causes HA-MRSA infections, and a USA300-related clone (SCCmec IVc) in CA-MRSA infections, which differ in the content of clinically important virulence genes. This study confirms that PVL is not a determinant of severity or mortality in CA-MRSA infections.

Impacto de la resistencia a antimicrobianos y de serotipos de Streptococcus pneumoniae en la mortalidad de niños menores de 5 años con enfermedad invasora

A retrospective cohort study was conducted to determine the impact of antimicrobial resistance of Streptococcus pneumoniae and of capsular types on mortality in children under 5 in Colombia. Data were from the Pan American Health Organizations Regional System for Vaccines study of S. pneumoniae serotypes. Severe pneumonia and meningitis caused by S. pneumoniae continue to be associated with high mortality rates. Clinical records of 245 children under 5 treated for invasive disease caused by S. pneumoniae between 1994 and 1996 in hospitals in Bogota Cali and Medellin were analyzed. There were 124 cases of pneumonia 104 of meningitis 8 of peritonitis and 6 of arthritis. 29 of the 245 children died including 13 of the 82 girls (15.9%) and 16 of the 163 boys (9.8%). 20 (19.2%) died of meningitis 8 (6.4%) of pneumonia and 1 (5.9%) of peritonitis. No significant differences between those dying and surviving were found in univariate analysis of age sex underlying disease or concordance of antimicrobial treatment. Variables associated with mortality in the univariate analysis included diagnosis of meningitis; resistance to penicillin trimethoprim-sulfamethoxazole (TMS) or erythromycin; multiresistance; and serotypes 6 23F 7F 8 and 35B. Factors associated with mortality in logistic regression were serotypes 7F (OR = 7.13 P = 0.04) and 8 (OR = 13.8 P = 0.07) meningitis (R = 5.02 P = 0.0001) resistance to TMS (OR = 2.62 P = 0.02) and polypnea (OR = 2.74 P = 0.03). Antimicrobial resistance was the factor most associated with mortality in meningitis patients while serotype was most consistently associated in pneumonia patients.Las enfermedades invasoras ocasionadas por Streptococcus pneumoniae han sido por mucho tiempo una causa importante de mortalidad. Si bien se sabe que la resistencia de S. pneumoniae a la penicilina y otros antimicrobianos se ha incrementado con el tiempo, aun no se ha esclarecido el efecto de este cambio sobre la mortalidad. Se desconoce igualmente el impacto de la virulencia de los tipos capsulares del microorganismo en la mortalidad. El objetivo de este estudio de cohorte retrospectivo fue determinar los factores de riesgo de mortalidad por enfermedad neumococica en ninos menores de 5 anos. Durante un estudio de serotipificacion de S. pneumoniae patrocinado por el Sistema Regional de Vacunas de la OPS se revisaron con este fin las fichas epidemiologicas de 245 pacientes de esa edad en quienes se diagnostico enfermedad invasora por S. pneumoniae entre 1994 y 1996 en Colombia. De los 245 pacientes, 29 (11%) fallecieron. En el analisis univariado no se establecieron diferencias significativas entre los pacientes que murieron y aquellos que sobrevivieron en cuanto a edad, sexo, procesos patologicos subyacentes al ingresar, o concordancia del tratamiento antimicrobiano recibido. Las variables que se asociaron con la mortalidad fueron un diagnostico de meningitis; infeccion por S. pneumoniae resistente a la penicilina, trimetoprima-sulfametoxazol (TMS) o eritromicina; multirresistencia, y los tipos capsulares 6, 23F, 7F, 8 y 35 B. En el analisis por regresion logistica siguieron mostrando asociacion con la mortalidad los tipos capsulares 7F (razon de posibilidades u odds ratio [OR]) = 7,13; P = 0,04) y 8 (OR = 13,8; P = 0,07), la polipnea (OR = 2,74; P = 0,03), el diagnostico de meningitis (OR = 5,02; P = 0,0001) y la resistencia a TMS (OR = 2,62; P = 0,02). En los casos de neumonia, el factor que mas se asocio con la mortalidad fue el tipo capsular, mientras que en los casos de meningitis, dicho factor fue la resistencia a antimicrobianos. En el desarrollo de una vacuna deberian tenerse en cuenta las diferencias de mortalidad segun los serotipos, a fin de lograr un mayor impacto en la morbilidad y mortalidad infantiles por enfermedad de origen neumococico.Severe pneumonia and meningitis caused by Streptococcus pneumoniae have been persistently associated with high mortality rates, despite advances in antimicrobial therapy and the development of vaccines. Resistance to penicillin and other antimicrobial agents is increasing and spreading worldwide. Even though risk factors for development of antimicrobial resistance have been identified, their influence on mortality has not been clarified. With regard to virulence, differences among serotypes have been determined, but their impact on mortality is unknown. The aim of this study was to determine the risk factors associated with mortality in children with invasive pneumococcal disease. Clinical records for 245 children under 5 years of age with invasive disease due to S.pneumoniae were reviewed. Children were diagnosed between 1994 and 1996 in Colombia, during the study of S.pneumoniae capsular types conducted by the Pan American Health Organizations Regional System for Vaccines. Of the 245 patients whose charts were examined, 29 (11%) died. No significant differences in age, gender, underlying disease, nor antimicrobial treatment concordance were found. Variables associated with mortality in the univariate analysis were a diagnosis of meningitis; antimicrobial resistance to penicillin, trimethoprim-sulfamethoxazole (TMS), or erythromycin; multiresistance, and serotypes 6, 23F, 7F, 8, and 35B. In the logistic regression, serotypes 7F (OR = 7.13; P = 0.04) and 8 (OR = 13.8; P = 0.07), polipnea (OR = 2.74; P = 0.03), meningitis (OR = 5.02; P = 0.0001) and TMS resistance (OR = 2.62; P = 0.02) continued to be associated with mortality. In patients with pneumonia, serotype was the factor most consistently associated with mortality; in meningitis patients, it was antimicrobial resistance. Differences in mortality according to serotype must be taken into account in developing a vaccine if a substantial impact on pneumococcal disease morbidity and mortality is to be achieved.

Perfil microbiológico de aislamientos en unidades neonatales en un hospital de tercer nivel de Bogotá, Colombia

OBJECTIVES: Investigating the prevalence and sensitivity of germs isolated from newborn in a referral hospital in Bogota. Suggesting an empirical antibiotic treatment for neonatal infection. METHODS: Cultures taken between February and December 2002 were analysed. Blood cultures were processed using BacT/ALERT (Durham, NC), urine cultures by UROCULT (Bio-Bacter) and catheter tips in thioglycollate. BBL CRYSTAL identification system (BD, Sparks, MD) was used for identifying germs. Antibiotic sensitivity was determined by disk diffusion. RESULTS: There were 1,097 positive aerobic and facultative aerobic germ cultures; 64,3% were Gram-positive, 30,6% Gram-negative and 4,9% were yeasts. Gram-positive germs consisted of coagulase-negative staphylococci (64,2%), enterococcus (13,8%) and coagulase-positive staphylococci (13,3%). The most frequent Gram-negatives were Klebsiella (45,2%), Eschericha coli (30,9%) and Serratia (10,1%). Staphylococcus epidermidis accounted for 64% of the coagulase-negative staphylococci. S. epidermidis susceptibility to vancomycin was 100%. Coagulase-negative staphylococci susceptibility to rifampin and amikacin was 59% and 67,4% (respectively). Coagulase-negative staphylococci resistance to beta-lactams was 86,4% (95% CI: 82,3-89,9). Coagulase-positive staphylococci sensitivity to vancomycin was 100%. Gram-negative susceptibility to imipenem was 98,1% (95% CI: 89,9-99,9), 78,1% to gentamicin (95% CI: 64,9-88,2) and 46,6% to amikacin (95% CI: 28,3-65,7). CONCLUSIONS: There was high coagulase-negative staphylococci prevalence in neonatal infection (particularly S. epidermidis). All S. epidermidis and coagulase-positive staphylococci were sensitive to vancomycin. There was increasing coagulase-negative staphylococci and Gram-negative resistance to oxacillin and amikacin, respectively.

Frequency of microorganisms isolated in patients with bacteremia in intensive care units in Colombia and their resistance profiles

OBJECTIVE The aim of this study was to describe the most frequently found bacterial microorganisms in bloodstream isolates taken from patients in intensive care units in Colombia and their resistance profiles. METHODS This was a multicentre descriptive observational study that was carried out between January 2001 and June 2008 with laboratory data from 33 participating hospitals in a surveillance network. RESULTS The most frequently found microorganisms were coagulase-negative Staphylococci 39.6%, Staphylococcus aureus 12.3%, Klebsiella pneumoniae 8.2%, Escherichia coli 5.7%, Acinetobacter baumannii, 4.0% and Pseudomonas aeruginosa 3.8%. Coagulase-negative Staphylococci registered greater than 70% oxacillin resistance rate. S. aureus presented a change in its multiresistance profile during the years of follow-up. There was a trend towards a lower resistance rate among E. coli and K. pneumoniae isolates during the study period while A. baumannii carbapenem resistance rate exceeded 50%. DISCUSSION There has been a change in the frequency of species being isolated with a higher frequency of enterobacteriaceae compared to Gram-positive microorganisms, in general with a high resistance rate.

Early dissemination of OXA-72-producing Acinetobacter baumannii strain in Colombia: a case report

Nosocomial infections caused by carbapenem-resistant Acinetobacter baumannii isolates have reached epidemic levels in past decades. Currently this microorganism is responsible for outbreaks of difficult eradication and with high mortality rates worldwide. We herein report a rare case of an OXA-72-producing A. baumannii isolate colonizing a 47-year-old male patient with peritonitis due to abdominal stab wound, four years earlier than the first report of this carbapenemase in Acinetobacter pittii in Colombia. Although OXA-72 presents a low prevalence compared with OXA-23, our study demonstrated that A. baumannii isolates carrying the blaOXA-72 gene were present in the hospital environment in Colombia and could act as a reservoir for further spread to other Acinetobacter species, like A. pittii, causing carbapenem-resistance.