Comparative Analysis of Carbapenem-Resistant Acinetobacter baumannii Sequence Types in Southern Brazil: From the First Outbreak (2007-2008) to the Endemic Period (2013-2014).

Acinetobacter baumannii is considered an important pathogen of clinical significance that is responsible for a wide range of nosocomial infections. Carbapenem resistance among A. baumannii isolates has increased dramatically in the Past years because of the emergence and dissemination of specific epidemic clones. We aimed to characterize the population structure of A. baumannii isolates from Porto Alegre city, Southern Brazil, in two distinct periods: during the first carbapenem-resistant A. baumannii (CRAB) outbreak (2007-2008) and 5 years later when the CRAB reached endemic levels (2013-2014). The study included 49 CRAB isolates collected in two periods: 2007-2008 (31 isolates) and 2013-2014 (18 isolates). Multilocus sequence typing (MLST) was performed according to Institute Pasteur, followed by eBURST analysis. PCR was used to detect integrase gene, blaNDM, and oxacillinase genes, and also to detect the ISAba1 element upstream blaOXA-23. The eBURST analysis identified the clonal complexes (CCs) CC15, CC32, CC79, CC216, CC221, and CC464 in the first period (2007-2008) and CC1, CC2, CC15, CC79, and CC162 during the endemic period (2013-2014). Molecular analysis by MLST identified 13 new sequence types. As we found A. baumannii with the blaOXA-23 gene of several CCs, it can be concluded that the increase of CRAB infections are not related to a specific clone. Furthermore, the high-risk CC15 and CC79 were related to the first CRAB outbreak and these CCs persisted up to 2014 in Porto Alegre city. The international clones CC1 and CC2 were observed for the first time in only the second period (2013-2014), alerting to the emergence of these clones in Southern Brazil.

Genetic Background of ß-Lactamases in Enterobacteriaceae Isolates from Environmental Samples.

The prevalence of ß-lactamase-producing Enterobacteriaceae has increased worldwide. Although antibiotic-resistant bacteria are usually associated with hospitals, there are a growing number of reports of resistant bacteria in other environments. Concern about resistant microorganisms outside the hospital setting highlights the need to investigate mechanisms of antibiotic resistance in isolates collected from the environment. The present study evaluated the resistance mechanism to ß-lactam antibiotics in 40 isolates from hospital sewage and surface water from the Dilúvio Stream, Porto Alegre City, Southern Brazil. The multiplex PCR technique was used to detect several resistance genes of ß-lactamases: extended-spectrum ß-lactamases (ESBLs), carbapenemases, and ß-lactamase AmpC. After genes, detection amplicons were sequenced to confirm their identification. The clonal relationship was established by DNA macrorestriction using the XbaI enzyme, followed by pulsed-field gel electrophoresis (PFGE). The results indicated that resistance genes were present in 85% of the isolates. The most prevalent genes encoded narrow-spectrum ß-lactamase, such as TEM-1 and SHV-1 with 70% of the strains, followed by carbapenemase KPC and GES (45%), ESBL types SHV-5 and CTX-M-8 (27.5%), and AmpC (ACT-1/MIR-1) (2.5%). Twelve isolates contained only one resistance gene, 14 contained two, and eight isolates had three resistance genes. PFGE indicated a clonal relationship among K. pneumoniae isolates. It was not possible to establish a clonal relationship between Enterobacter sp. isolates. The results highlight the potential of these resistance genes to spread in the polluted environment and to present a health risk to communities. This report is the first description of these resistance genes present in environmental samples other than a hospital in the city of Porto Alegre/RS.

High prevalence of Neisseria meningitidis hypervirulent lineages and emergence of W135:P1.5,2:ST-11 clone in Southern Brazil.

OBJECTIVES: The aim of this study was to characterize Neisseria meningitidis strains causing invasive disease in Rio Grande do Sul (RS), during 2003-2005, monitoring the occurrence of hypervirulent lineages, as well as to determine the diversity of PorA VR types for the corresponding isolates and clinical specimens. METHODS: Isolates and clinical specimens were characterized by MLST and PorA VR typing. RESULTS: This study demonstrated high prevalence of some hypervirulent lineages and emergence of new ones, including the emergence of lineages W135:P1.5,2:ST-11 complex, and C:P1.22,14-6:ST-103 complex. These lineages are probably responsible for the increasing incidence of serogroups C and W135, despite the overall decrease in serogroup B cases during the period. The most prevalent complex was serogroup B ST-32/ET-5 complex. The most prevalent PorA types found for serogroup B were P1.19,15, P1.7,16, and P1.18-1,3, representing a different distribution of PorA types compared to other states of Brazil. CONCLUSIONS: This study highlights the importance of monitoring each population, even within the same country. The different distribution of PorA VR types in RS has implications in vaccine design and efficacy. Detailed and accurate meningococcal characterization is an important element in studies of meningococcal epidemiology, population biology, and evolution and provides information for the design of control strategies.