ANTIMICROBIALAGENTS ANDCHEMOTHERAPY, Sept. 2011, p. 4494–4495 Vol. 55, No. 9 0066-4804/11/$12.00 doi:10.1128/AAC.00295-11
Copyright © 2011, American Society for Microbiology. All Rights Reserved.
Low Prevalence of
bla
OXA-143in Private Hospitals in Brazil
We read with great interest C. S. Antonio et al.’s letter describing the high prevalence ofAcinetobacter baumannii car-ryingblaOXA-143in 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 An-tonio et al. (1).
During 2008, a total of 803 Gram-negative bacillus iso-lates, 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. bau-manniiisolates that were recovered mainly from the respi-ratory tract (70.3%) and bloodstream (24.2%). Susceptibil-ity testing was performed by CLSI broth microdilution (3). The detection of metallo--lactamase (ML)- and carbap-enem-hydrolyzing class D -lactamase (CHDL)-encoding genes was performed by multiplex PCR (5, 7, 9) and con-firmed by sequencing. The presence of the insertion se-quence ISAba1upstream of the CHDL-encoding genes was also investigated. Genetic relatedness among CHDL-pro-ducing 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 carbap-enems. We also observed low rates of susceptibility to ami-kacin (18.7%), ceftazidime (12.1%), cefepime (8.8%), pip-eracillin-tazobactam (3.3%), and ciprofloxacin (3.3%). In contrast, most A. baumannii isolates were susceptible to polymyxin B (MIC90, 1 g/ml; 97.8% of the isolates were susceptible).
ML-encoding genes were not identified in our study, as was also reported by Antonio et al. (1). However, we identified the
blaOXA-23gene in carbapenem-resistant isolates more fre-quently than in the former study (83.5% versus 41.7%). The
blaOXA-23gene was found in all carbapenem-resistant iso-lates from the cities of Belo Horizonte, Blumenau, Curitiba, and Sa˜o Luís, followed by Rio de Janeiro (93.7%), Porto Alegre (80.0%), and Sa˜o Paulo (69.0%). These results are in accordance with previous local reports (2, 4, 6) that empha-size that this gene is widespread in our country. The ISAba1
element was positioned upstream ofblaOXA-23in all isolates, whereas no insertion sequence was observed upstream of
blaOXA-51. Although A. baumannii carrying blaOXA-58 and blaOXA-72had 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-producingA. baumanniiisolates. 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 iden-tified in specific locations.
While Antonio et al. (1). reported a high prevalence of the
blaOXA-143gene (58.3%), we found that only 7 of 83 (8.4%)A. baumanniiisolates carried this gene. These isolates were col-lected from a few hospitals located in the cities of Sa˜o Paulo (n ⫽ 6) and Rio de Janeiro (n ⫽ 1). In both studies, the majority of OXA-143-producingA. baumanniiisolates were recovered from cities located in Sa˜o Paulo State. However, while Antonio et al. observed that 70% (21/30) of the iso-lates 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 Sa˜o Paulo. Moreover, we have observed the predominance of a single PFGE clone among the seven OXA-143-producingA. bau-mannii isolates, which contrasts with results obtained by Antonio et al., in which 7 distinct enterobacterial repetitive intergenic consensus sequence (ERIC) PCR clones har-bored theblaOXA-143gene. 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-pro-ducing isolates (1). The high prevalence ofblaOXA-23found 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 in-fection control measures. Thus, wide national surveillance studies are necessary to analyze the real prevalence of CHDLs in Brazilian hospitals.
REFERENCES
1.Antonio, C. S., et al.2011. High prevalence of carbapenem-resistant Acineto-bacter baumanniicarrying theblaOXA-143gene in Brazilian hospitals.
Antimi-crob. Agents Chemother.55:1322–1323.
2.Carvalho, K. R., et al.2009. Dissemination of multidrug-resistant Acinetobac-ter baumanniigenotypes carryingblaOXA-23collected from hospitals in Rio de
Janeiro, Brazil. Int. J. Antimicrob. Agents34:25–28.
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 Acineto-bacter baumanniiproducing the OXA-23 enzyme in Curitiba, Brazil. J. Clin. Microbiol.41:3403–3406.
5.Higgins, P. G., L. Poirel, M. Lehmann, P. Nordmann, and H. Seifert.2009. OXA-143, a novel carbapenem-hydrolyzing class D beta-lactamase in
Acinetobacter baumannii. Antimicrob. Agents Chemother. 53:5035– 5038.
6.Martins, A. F., et al.2009. Carbapenem-resistantAcinetobacter baumannii
producing the OXA-23 enzyme: dissemination in southern Brazil. Infection
37:474–476.
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.
8.Werneck, J. S., R. C. Pica˜o, C. G. Carvalhaes, J. P. Cardoso, and A. C. Gales.
2011. OXA-72-producingAcinetobacter baumanniiin Brazil: a case report. J. Antimicrob. Chemother.66:452–454.
9.Woodford, N., et al.2006. Multiplex PCR for genes encoding prevalent OXA carbapenemases inAcinetobacterspp. Int. J. Antimicrob. Agents27:
351–353.
Je´ssica S. Werneck* Renata C. Pica˜o Raquel Girardello Rodrigo Cayoˆ Vitor Marguti
Laborato´rio ALERTA Division of Infectious Diseases
Universidade Federal de Sa˜o Paulo (UNIFESP) Sa˜o Paulo, Brazil
Líbera Dalla-Costa
Hospital de Clínicas
Universidade Federal do Parana´ Curitiba, Brazil
Ana C. Gales
Laborato´rio ALERTA Division of Infectious Diseases
Universidade Federal de Sa˜o Paulo (UNIFESP) Sa˜o Paulo, Brazil
*Phone and fax: 55 (11) 55764748 E-mail: jessica.s.werneck@gmail.com
Authors’ Reply
The foregoing letter by Werneck et al. provides additional information on the occurrence of carbapenem-hydrolyzing class D-lactamase (CHDL)-encoding genes among Acineto-bacter baumannii isolates collected from private hospitals in Brazil. In the results, the authors reported a lower prevalence ofblaOXA-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-producingA. bauman-nii 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-producingA. baumanniiin Rio de Janeiro (second-largest metropolitan area in Brazil after Sa˜o Paulo), which is worri-some, since, apparently, strains of A. baumannii carrying
blaOXA-143 have been restricted to hospitals located in Sa˜o 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 thatA. baumanniistrains carryingblaOXA-143genes are
spread-ing 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-producingPseudomonas aerugi-nosastrains 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. baumanniiisolates. The rapid emergence of these isolates and their potential spread require very close monitoring and surveillance.
REFERENCES
1.Antonio, C. S., et al.2011. High prevalence of carbapenem-resistant Acineto-bacter baumanniicarrying theblaOXA-143gene in Brazilian hospitals.
Antimi-crob. Agents Chemother.55:1322–1323.
2.Gales, A. C., L. C. Menezes, S. Silbert, and H. S. Sader.2003. Dissemination in distinct Brazilian regions of an epidemic carbapenem-resistant Pseudomo-nas aeruginosaproducing SPM metallo-beta-lactamase. J. Antimicrob. Che-mother.52:699–702.
3.Higgins, P. G., L. Poirel, M. Lehmann, P. Nordmann, and H. Seifert.2009. OXA-143, a novel carbapenem-hydrolyzing class D beta-lactamase in Acin-etobacter baumannii. Antimicrob. Agents Chemother.53:5035–5038. 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.
Charline S. Antonio Patrícia R. Neves Micheli Medeiros Elsa M. Mamizuka
Department of Clinical Analysis School of Pharmacy
Universidade de Sa˜o Paulo Sa˜o Paulo, Brazil
Maria R. Elmor de Arau´jo
Laboratory of Clinical Microbiology Hospital Beneficeˆncia Portuguesa Sa˜o Paulo, Brazil
Nilton Lincopan*
Department of Microbiology Institute of Biomedical Sciences Universidade de Sa˜o Paulo CEP 05508-000
Sa˜o Paulo, Brazil
*Phone: 55 (11) 3091 7296 Fax: 55 (11) 3091 7354 E-mail: lincopan@usp.br
