Antimicrobial Susceptibility StudiesAntimicrobial resistance among Gram-negative bacilli isolated from Latin America: results from SENTRY Antimicrobial Surveillance Program (Latin America, 2008–2010)
Introduction
Infections caused by multidrug-resistant isolates are associated with increased costs, length of hospitalization, and, especially, morbidity and mortality rates (Evans et al., 2007). Resistance among Gram-negative organisms is of great concern, since few antimicrobial agents are effective to treat infections caused by these pathogens and a limited number of antimicrobial agents are in late stage of development. Surveillance studies are undertaken to help direct antimicrobial use, particularly empiric therapy, based on the local resistance patterns of organisms, and implementation of infection control measures (Jones, 1996). From a public health perspective, surveillance data can be employed to identify points for intervention to control bacterial resistance and, subsequently, to assess the effectiveness of these interventions (Jones, 1996).
A limited number of Latin American countries possess a nationwide surveillance programs for monitoring antimicrobial resistance like Argentina, Chile, and Colombia (Briceno et al., 2010, Garcia, 2003, Rossi et al., 1999). Unfortunately, other countries like Brazil and Mexico do not have a national program for monitoring antimicrobial resistance in the hospital setting yet, making it even more difficult to estimate the real prevalence and burden of disease caused by antimicrobial resistant bacteria (Okeke et al., 2005). The SENTRY Antimicrobial Surveillance Program has been monitoring the predominant pathogens and antimicrobial resistance patterns of nosocomial- and community-acquired infections via a broad network of sentinel hospitals since 1997 (Pfaller et al., 1998). The monitored infections include bloodstream infections (20 consecutive isolates per month), pneumonia (100 consecutive isolates collected in a 6-month period each year), and skin and soft tissue infections including surgical wound infections (100 consecutive isolates collected in a 6-month period each year).
More recently, with broader dissemination of Klebsiella pneumoniae carbapenemase (KPC)–producing Enterobacteriaceae and oxacillinase (OXA)-carbapenemase–producing Acinetobacter spp. isolates, a rapid decrease in the susceptibility to carbapenems has been noticed in many parts of the world, including Latin America. The objective of this study was to update the frequency and resistance rates of Gram-negative pathogens isolated from Latin American sites enrolled in the SENTRY Program between 2008 and 2010 and summarize molecular characterization data for subsets of carbapenemase-producing strains.
Section snippets
Bacterial strains
A total of 12,811 bacterial isolates, including 5704 (44.5%) Gram-negative bacilli, from hospitalized patients with serious community-acquired or nosocomial-acquired infections were recovered between January 2008 and December 2010 and submitted to the SENTRY Program. The organisms were consecutively collected from various infection sites and only 1 isolate per patient was included in the study. The medical centers were guided by common protocols. All isolates were identified in the participant
Results
A total of 5704 (44.5%) of 12,811 bacterial isolates collected from Latin American medical centers were identified as Gram-negative bacilli. They were collected from Argentina (19.6%), Brazil (40.9%), Chile (18.4%), and Mexico (18.4%). Most of these isolates were collected from patients diagnosed with bloodstream infections (BSI; 52.6%); skin and soft tissue infections, including surgical wound infections (SSTI; 22.9%); and pneumonia (13.1%). The most common causes of BSI were Staphylococcus
Discussion
In this study, we have confirmed that Gram-negative bacilli account for a significantly higher proportion of etiologic agents of infections in Latin America compared to the USA and Canada. An even more striking difference is the very high percentage of infections caused by P. aeruginosa and Acinetobacter spp. compared to North American medical centers (Pfaller et al., 1998). This difference could be explained by the geographic location of Latin America since most of it lies in the tropical zone
Acknowledgments
The authors would like to thank the following investigators for kindly contributing strains to the study: José M. Casellas (Sanatorio Parque y Niño, Rosario, Santa Fe, Argentina); Jorgelina Smayevsky (Laboratorio CEMIC, Buenos Aires, Argentina); Ana C. Gales (Federal University of São Paulo, São Paulo, Brazil); Cássia Zoccoli (Laboratório Médico Santa Luzia, Florianópolis, Brazil); Afonso Barth (Hospital de Clínicas, Porto Alegre, Brazil); Julival Ribeiro (Hospital de Base, Brasília, Brazil);
References (23)
The emergent needs for basic research, education, and surveillance of antimicrobial resistance. Problems facing the report from the American Society for Microbiology Task Force on Antibiotic Resistance
Diagn Microbiol Infect Dis
(1996)- et al.
Hospital outbreak caused by Klebsiella pneumoniae producing KPC-2 beta-lactamase resistant to colistin
J Hosp Infect
(2010) - et al.
Antimicrobial resistance in developing countries: Part II. Strategies for containment
Lancet Infect Dis
(2005) - et al.
Four-year evaluation of frequency of occurrence and antimicrobial susceptibility patterns of bacteria from bloodstream infections in Latin American medical centers
Diagn Microbiol Infect Dis
(2002) - et al.
Increasing prevalence of extended-spectrum-beta-lactamase among Gram-negative bacilli in Latin America—2008 update from the Study for Monitoring Antimicrobial Resistance Trends (SMART)
Braz J Infect Dis
(2011) - et al.
Antimicrobial resistance of Gram-negative bacilli isolated from tertiary-care hospitals in Colombia
Biomedica
(2010) - et al.
Cloverleaf test (modified Hodge test) for detecting carbapenemase production in Klebsiella pneumoniae: be aware of false positive results
J Antimicrob Chemother
(2010) - et al.
Trends in carbapenemase-producing Escherichia coli and Klebsiella spp. from Europe and the Americas: report from the SENTRY Antimicrobial Surveillance Programme (2007–09)
J Antimicrob Chemother
(2011) - et al.
Expansion of clonal complex 258 KPC-2-producing Klebsiella pneumoniae in Latin American hospitals: report of the SENTRY antimicrobial surveillance program
Antimicrob Agents Chemother
(2012) Performance standards for antimicrobial susceptibility testing: 18th informational supplement (M100-S18)
(2008)