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Enterobacteria-producing extended-spectrum ß-lactamases (ESBL) play an important role in healthcare infections, increasing hospitalization time, morbidity and mortality rates. Among several ESBLs that emerge from these pathogens, CTX-M-type enzymes had the most successful global spread in different epidemiological settings. Latin America presents high prevalence of CTX-M-2 in ESBL-producing enterobacterial infections with local emergence of the CTX-M-1 group. However, this high prevalence of the CTX-M-1 group has not yet been reported in Chile. The aim of this study was to identify ESBLs among enterobacteria isolated from clinical samples of critically ill patients from southern Chile. One-hundred thirty seven ESBL-producing bacteria were isolated from outpatients from all critical patient units from Hernán Henríquez Aravena Hospital. Phenotype characterization was performed by antibiogram, screening of ESBL, and determination of minimum inhibitory concentration (MIC). PCR was used for genetic confirmation of resistance. Molecular typing was performed by ERIC-PCR. ESBL-producing isolates were identified as Klebsiella pneumoniae (n=115), Escherichia coli (n=18), Proteus mirabilis (n=3), and Enterobacter cloacae (n=1), presenting multidrug resistance profiles. PCR amplification showed that the strains were positive for blaSHV (n=111/81%), blaCTX-M-1 (n=116/84.7%), blaTEM (n=100/73%), blaCTX-M-2 (n=28/20.4%), blaCTX-M-9 (0.7%), blaPER-1 (0.7%), and blaGES-10 (0.7%). The multiple production of ESBL was observed in 93% of isolates, suggesting high genetic mobility independent of the clonal relationship. The high frequency of the CTX-M-1 group and a high rate of ESBL co-production are changing the epidemiology of the ESBL profile in Chilean intensive care units. This epidemiology is a constant and increasing challenge, not only in Chile, but worldwide.

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ABSTRACT Enterobacteria-producing extended-spectrum β-lactamases (ESBL) play an important role in healthcare infections, increasing hospitalization time, morbidity and mortality rates. Among several ESBLs that emerge from these pathogens, CTX-M-type enzymes had the most successful global spread in different epidemiological settings. Latin America presents high prevalence of CTX-M-2 in ESBL-producing enterobacterial infections with local emergence of the CTX-M-1 group. However, this high prevalence of the CTX-M-1 group has not yet been reported in Chile. The aim of this study was to identify ESBLs among enterobacteria isolated from clinical samples of critically ill patients from southern Chile. One-hundred thirty seven ESBL-producing bacteria were isolated from outpatients from all critical patient units from Hernán Henríquez Aravena Hospital. Phenotype characterization was performed by antibiogram, screening of ESBL, and determination of minimum inhibitory concentration (MIC). PCR was used for genetic confirmation of resistance. Molecular typing was performed by ERIC-PCR. ESBL-producing isolates were identified as Klebsiella pneumoniae (n = 115), Escherichia coli (n = 18), Proteus mirabilis (n = 3), and Enterobacter cloacae (n = 1), presenting multidrug resistance profiles. PCR amplification showed that the strains were positive for blaSHV (n = 111/81%), blaCTX-M-1 (n = 116/84.7%), blaTEM (n = 100/73%), blaCTX-M-2 (n = 28/20.4%), blaCTX-M-9 (0.7%), blaPER-1 (0.7%), and blaGES-10 (0.7%). The multiple production of ESBL was observed in 93% of isolates, suggesting high genetic mobility independent of the clonal relationship. The high frequency of the CTX-M-1 group and a high rate of ESBL co-production are changing the epidemiology of the ESBL profile in Chilean intensive care units. This epidemiology is a constant and increasing challenge, not only in Chile, but worldwide.

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We monitored Streptococcus pneumoniae serotypes causing invasive infections in patients admitted to one hospital in southern Chile during a 10-year period (1994 to 2004). All specimens isolated from patients with invasive S. pneumoniae infections were serotyped at the CDC in Atlanta, GA. A total of 508 isolates belonged to 58 serotypes. There were 95 infections in patients <2 years old, 33 infections in patients 2 to 4 years old, 61 infections in patients 5 to 14 years old, 66 infections in patients 15 to 44 years old, 134 infections in patients 45 to 64 years old, and 120 infections in patients >or=65 years old. The 10 serotypes isolated with the highest frequency in all groups were, in decreasing order, 1, 3, 14, 5, 19F, 6B, 7F, 12F, 23F, and 6A. The 10 most frequent isolates in children under 2 years of age were 1, 6B, 14, 19F, 5, 23F, 6A, 9V, and 7F. In patients >or=65 years old, the most common serotypes were 3, 7F, 1, 14, 19A, 23F, 19F, 35B, 4, and 5. Penicillin resistance was detected in 14 (2.7%) clinical specimens isolated since 1998, with 13 resistant strains identified since 2001. Vaccine coverage for the 7-valent conjugate vaccine was 42% for children <2 years of age. This study is important for the design of vaccines for this region and to evaluate public health measures to decrease pneumococcal infections.

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BACKGROUND: The permanent surveillance of antimicrobial susceptibility of Shigella sp in the Temuco Regional Hospital, allowed us to define the empirical use of antimicrobials in dysenteric syndrome. AIM: To study antimicrobial susceptibility of Shigella strains collected from 1997 to May 2001 and compare the results with those reported in 1990. MATERIAL AND METHODS: Two hundred and seventeen Shigella strains, coming from stool cultures of pediatric patients, were studied. RESULTS: In the period 1989-1990 Shigella flexneri was the main species isolated (83%) whereas, in the period 1997-2001, Shigella sonnei (55.8%) predominated. In the second period, an increase of antimicrobial resistance, as compared with the period 1989-1990, was observed for ampicillin (74.5 and 42% respectively), for cotrimoxazol (57.5 and 45% respectively) and tetracycline (64 and 8% respectively). Chloramphenicol resistance increased from 0 to 57.5%. In the second period no resistance to ciprofloxacin was detected. There was simultaneous resistance to four drugs in 30% of the strains, predominating multiresistance in S flexneri (52.1%). CONCLUSIONS: In the two periods studied, a significant increase was detected in the resistance of Shigella strains to antimicrobials.

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Se analizan 14 casos de pacientes hospitalizados con diagnóstico de M.B. en el Servicio de Pediatría del Hospital Regional Temuco, durante el período Mayo-Septiembre de 1985, para evaluar la utilidad de la prueba de Aglutinación del Látex en relación al cultivo y Gram en Líquido Celaforraquídeo (LCR). Las edades de los niños fluctuaron entre 3 meses y 8 años; el 53% fueron mujeres y 91% eutróficos. En 2 casos que se descartó el diagnóstico de M.B. por examen citoquímico, Gram y cultivo de LCR, el Látex también fue negativo. 10 niños tuvieron reacción del Látex(-), 8 cultivos (-) y en 6 la tinción de Gram fue (-). La sensibilidad de la reacción del Látex fue del 90,0%, en tanto que la del cultivo y Gram 66,6% y 54,5% respectivamente. La especificidad del método en estudio fue 100%, no registrándose falsos positivos ni negativos. El látex fue el único método de pesquisa etiológica en 3 niños (25%)

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