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Antimicrob Agents Chemother. Sep 2011; 55(9): 4494–4495.
PMCID: PMC3165347

Low Prevalence of blaOXA-143 in Private Hospitals in Brazil

LETTER

We read with great interest C. S. Antonio et al.'s letter describing the high prevalence of Acinetobacter baumannii carrying blaOXA-143 in Brazilian hospitals (1). Recently, we carried out a similar study, and although the blaOXA-143 gene was identified, its frequency was lower than that reported by Antonio et al. (1).

During 2008, a total of 803 Gram-negative bacillus isolates, 1 isolate per patient, were collected from 17 private hospitals located in eight cities from four distinct geographic Brazilian regions. Among them, 91 (11.3%) were A. baumannii isolates that were recovered mainly from the respiratory tract (70.3%) and bloodstream (24.2%). Susceptibility testing was performed by CLSI broth microdilution (3). The detection of metallo-β-lactamase (MβL)- and carbapenem-hydrolyzing class D β-lactamase (CHDL)-encoding genes was performed by multiplex PCR (5, 7, 9) and confirmed by sequencing. The presence of the insertion sequence ISAba1 upstream of the CHDL-encoding genes was also investigated. Genetic relatedness among CHDL-producing A. baumannii isolates, including the first OXA-23-producing A. baumannii clone isolated in Brazil (4), was evaluated by pulsed-field gel electrophoresis (PFGE).

A total of 83/91 (91.2%) isolates were resistant to carbapenems. We also observed low rates of susceptibility to amikacin (18.7%), ceftazidime (12.1%), cefepime (8.8%), piperacillin-tazobactam (3.3%), and ciprofloxacin (3.3%). In contrast, most A. baumannii isolates were susceptible to polymyxin B (MIC90, 1 μg/ml; 97.8% of the isolates were susceptible).

MβL-encoding genes were not identified in our study, as was also reported by Antonio et al. (1). However, we identified the blaOXA-23 gene in carbapenem-resistant isolates more frequently than in the former study (83.5% versus 41.7%). The blaOXA-23 gene was found in all carbapenem-resistant isolates from the cities of Belo Horizonte, Blumenau, Curitiba, and São Luís, followed by Rio de Janeiro (93.7%), Porto Alegre (80.0%), and São Paulo (69.0%). These results are in accordance with previous local reports (2, 4, 6) that emphasize that this gene is widespread in our country. The ISAba1 element was positioned upstream of blaOXA-23 in all isolates, whereas no insertion sequence was observed upstream of blaOXA-51. Although A. baumannii carrying blaOXA-58 and blaOXA-72 had recently been described in Brazil (1, 8), no isolates carrying these variants were found in our study.

Nine distinct PFGE clones were identified among the 76 OXA-23-producing A. baumannii isolates. The predominance of a single clone (clone A [36.8% of the isolates]) was observed in isolates collected from six distinct Brazilian cities. This clone exhibited a PFGE profile similar to that of the first Brazilian clone producer of OXA-23 (4). A. baumannii belonging to clones B (17.1%) and D (9.2%) were also identified in isolates collected from distinct cities, while other genotypes were identified in specific locations.

While Antonio et al. (1). reported a high prevalence of the blaOXA-143 gene (58.3%), we found that only 7 of 83 (8.4%) A. baumannii isolates carried this gene. These isolates were collected from a few hospitals located in the cities of São Paulo (n = 6) and Rio de Janeiro (n = 1). In both studies, the majority of OXA-143-producing A. baumannii isolates were recovered from cities located in São Paulo State. However, while Antonio et al. observed that 70% (21/30) of the isolates from this region carried the blaOXA-143 gene, in the present study, we identified this resistance determinant in only 20.7% (6/29) of isolates collected from São Paulo. Moreover, we have observed the predominance of a single PFGE clone among the seven OXA-143-producing A. baumannii isolates, which contrasts with results obtained by Antonio et al., in which 7 distinct enterobacterial repetitive intergenic consensus sequence (ERIC) PCR clones harbored the blaOXA-143 gene. Nevertheless, in their study, the high prevalence of OXA-143-producing isolates could also be partially justified by the intrahospital spread of a single clone, which corresponded to 57.1% of all OXA-143-producing isolates (1). The high prevalence of blaOXA-23 found in our study may also be justified by intra- and interhospital spread of endemic clones. The results of these two studies show that the prevalence of CHDLs may vary according to the disseminated clone in a specific hospital or region and emphasize the importance of appropriate adherence to infection control measures. Thus, wide national surveillance studies are necessary to analyze the real prevalence of CHDLs in Brazilian hospitals.

Contributor Information

Vitor Marguti, Laboratório ALERTA Division of Infectious Diseases Universidade Federal de São Paulo (UNIFESP) São Paulo, Brazil.

Líbera Dalla-Costa, Hospital de Clínicas Universidade Federal do Paraná Curitiba, Brazil.

Ana C. Gales, Laboratório ALERTA Division of Infectious Diseases Universidade Federal de São Paulo (UNIFESP) São Paulo, Brazil.

REFERENCES

1. Antonio C. S., et al. 2011. High prevalence of carbapenem-resistant Acinetobacter baumannii carrying the blaOXA-143 gene in Brazilian hospitals. Antimicrob. Agents Chemother. 55:1322–1323 [PMC free article] [PubMed]
2. Carvalho K. R., et al. 2009. Dissemination of multidrug-resistant Acinetobacter baumannii genotypes carrying blaOXA-23 collected from hospitals in Rio de Janeiro, Brazil. Int. J. Antimicrob. Agents 34:25–28 [PubMed]
3. Clinical and Laboratory Standards Institute 2009. Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically, 8th ed Approved standard M07-A8. Clinical and Laboratory Standards Institute, Wayne, PA
4. Dalla-Costa L. M., et al. 2003. Outbreak of carbapenem-resistant Acinetobacter baumannii producing the OXA-23 enzyme in Curitiba, Brazil. J. Clin. Microbiol. 41:3403–3406 [PMC free article] [PubMed]
5. Higgins P. G., Poirel L., Lehmann M., Nordmann P., Seifert H. 2009. OXA-143, a novel carbapenem-hydrolyzing class D beta-lactamase in Acinetobacter baumannii. Antimicrob. Agents Chemother. 53:5035–5038 [PMC free article] [PubMed]
6. Martins A. F., et al. 2009. Carbapenem-resistant Acinetobacter baumannii producing the OXA-23 enzyme: dissemination in southern Brazil. Infection 37:474–476 [PubMed]
7. Mendes R. E., et al. 2007. Rapid detection and identification of metallo-beta-lactamase-encoding genes by multiplex real-time PCR assay and melt curve analysis. J. Clin. Microbiol. 45:544–547 [PMC free article] [PubMed]
8. Werneck J. S., Picão R. C., Carvalhaes C. G., Cardoso J. P., Gales A. C. 2011. OXA-72-producing Acinetobacter baumannii in Brazil: a case report. J. Antimicrob. Chemother. 66:452–454 [PubMed]
9. Woodford N., et al. 2006. Multiplex PCR for genes encoding prevalent OXA carbapenemases in Acinetobacter spp. Int. J. Antimicrob. Agents 27:351–353 [PubMed]
Sep 2011; 55(9): 4494–4495.

Authors' Reply

REPLY

The foregoing letter by Werneck et al. provides additional information on the occurrence of carbapenem-hydrolyzing class D β-lactamase (CHDL)-encoding genes among Acinetobacter baumannii isolates collected from private hospitals in Brazil. In the results, the authors reported a lower prevalence of blaOXA-143 (8.4%) among their study isolates than among the isolates in our previous report (58.3%), which included carbapenem-resistant A. baumannii isolates collected from public hospitals (1). In this regard, there are several factors to be considered for the apparently discordant results, besides hospital type. In fact, as mentioned by Werneck et al., in our study, the high prevalence of OXA-143-producing A. baumannii isolates could partially be justified by the intrahospital spread of a single clone. Regardless, valuable information in the letter by Werneck et al. was the identification of OXA-143-producing A. baumannii in Rio de Janeiro (second-largest metropolitan area in Brazil after São Paulo), which is worrisome, since, apparently, strains of A. baumannii carrying blaOXA-143 have been restricted to hospitals located in São Paulo (1). In this regard, the prevalence of CHDLs may also vary according to specific region. Thus, although data on OXA-143 are currently few (1, 3), there is supportive evidence that A. baumannii strains carrying blaOXA-143 genes are spreading in Brazilian hospitals (N. Lincopan et al., unpublished data).

Surprisingly, like the SPM-1 metallo-beta-lactamase, the novel OXA-143 enzyme was identified for the first time in Brazil (3, 4). Currently, SPM-1-producing Pseudomonas aeruginosa strains are endemic to and highly prevalent in Brazilian hospitals (2). So, for Brazil, the widespread occurrence of SPM-1 should provide a salutary lesson from which to draw experience in order to avoid the spread of OXA-143-producing A. baumannii isolates. The rapid emergence of these isolates and their potential spread require very close monitoring and surveillance.

Contributor Information

Elsa M. Mamizuka, Department of Clinical Analysis School of Pharmacy Universidade de São Paulo São Paulo, Brazil.

Maria R. Elmor de Araújo, Laboratory of Clinical Microbiology Hospital Beneficência Portuguesa São Paulo, Brazil.

Nilton Lincopan, Department of Microbiology Institute of Biomedical Sciences Universidade de São Paulo CEP 05508-000 São Paulo, Brazil.

REFERENCES

1. Antonio C. S., et al. 2011. High prevalence of carbapenem-resistant Acinetobacter baumannii carrying the blaOXA-143 gene in Brazilian hospitals. Antimicrob. Agents Chemother. 55:1322–1323 [PMC free article] [PubMed]
2. Gales A. C., Menezes L. C., Silbert S., Sader H. S. 2003. Dissemination in distinct Brazilian regions of an epidemic carbapenem-resistant Pseudomonas aeruginosa producing SPM metallo-beta-lactamase. J. Antimicrob. Chemother. 52:699–702 [PubMed]
3. Higgins P. G., Poirel L., Lehmann M., Nordmann P., Seifert H. 2009. OXA-143, a novel carbapenem-hydrolyzing class D beta-lactamase in Acinetobacter baumannii. Antimicrob. Agents Chemother. 53:5035–5038 [PMC free article] [PubMed]
4. Toleman M. A., et al. 2002. Molecular characterization of SPM-1, a novel metallo-beta-lactamase isolated in Latin America: report from the SENTRY Antimicrobial Surveillance Programme. J. Antimicrob. Chemother. 50:673–679 [PubMed]

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