LETTERS land. Furthermore, Ct. felis often Acknowledgments felis in Ctenocephalides spp. feeds on humans. We thank Alex Davies and Anne , Brazil. Emerg Infect Dis 2002;8:317–9. Clinicians encountering patients Seabright for assistance with collecting 5. Marquez FJ, Munain MA, Perez JM, with fever or rash (or both) and a his- and processing the fleas and D. Raoult for Panchon J. Presence of Rickettsia felis in tory of contact or bites should providing Rickettsia felis. the cat flea from southwestern Europe. consider a diagnosis of R. felis. Emerg Infect Dis 2002;8:89–91. Novartis UK provided financial 6. Schriefer ME, Sacci JB Jr, Dumler JS, Laboratory confirmation of infection assistance with this project. Bullen MG, Azad AF. Identification of a is not easy, but in vitro culture of R. novel rickettsial infection in a patient diag- felis, and hence material for a sero- nosed with murine . J Clin Microbiol logic assay for the diagnosis of Martin J. Kenny,* 1994;32:949–54. Richard J. Birtles,† 7. Richter J, Fournier PE, Petridou J, human R. felis infections, has recent- Haussinger D, Raoult D. Rickettsia felis ly been described, and serology Michael J. Day,* infection acquired in Europe and docu- appears to be an accurate indicator of and Susan E. Shaw* mented by polymerase chain reaction. exposure (9). As with other spotted *University of Bristol, Langford, Somerset, Emerg Infect Dis 2002;8:207–8. 8. Zavala-Velazquez JE, Ruiz-Sosa JA, fever group rickettsial infections, United Kingdom; and †University of Liverpool, Leahurst, Neston, Cheshire, Sanchez-Elias RA, Becerra-Carmona G, molecular diagnostics may provide a United Kingdom Walker DH. Rickettsia felis in useful alternative approach to detect- Yucatan. Lancet 2000;356:1079–80. ing and identifying R. felis in infected 9. La Scola B, Meconi S, Fenollar F, Rolain References JM, Roux V, Raoult D. Emended descrip- tissues. In culture, R. felis has been tion of Rickettsia felis (Bouyer et al. 2001), 1. Azad AF, Sacci JB Jr, Nelson WM, Dasch shown to be resistant to erythromycin a temperature-dependent cultured bacteri- GA, Schmidtman ET, Carl M. Genetic um. Int J Syst Evol Microbiol (unlike other rickettsia), gentamicin, characterization and transovarial transmis- 2002;52:2035–41. amoxicillin, and trimethoprim-sul- sion of a novel typhus-like rickettsia found 10. Rolain JM, Stuhl L, Maurin M, Raoult D. in cat fleas. Proc Natl Acad Sci U S A famethoxazole. Thus, infection with Evaluation of antibiotic susceptibilities of 1992;89:43–62. this bacterium should be considered three rickettsial species including Rickettsia 2. Higgins JA, Radulovic S, Schriefer ME, felis by a quantitative PCR DNA assay. in cases of antibiotic-insensitive fever Azad AF. Rickettsia felis: a new species of Antimicrob Agents Chemother 2002; with a rash, especially in young, old, pathogenic rickettsia isolated from cat and immunosuppressed persons. The fleas. J Clin Microbiol 1996;34:671–4. 46:2747–51. organism is sensitive to doxycycline, 3. Bouyer DH, Stenos J, Crocquet-Valdes P, Moron CG, Popov VL, Zavala-Velazquez Address for correspondence: Susan E. Shaw, rifampicin, thiamphenicol, and fluo- JE, et al. Rickettsia felis: molecular charac- Department of Clinical Veterinary Sciences, roquinolones (10) terization of a new member of the spotted University of Bristol, Langford, Somerset, fever group. Int J Syst Evol Microbiol 2001;51:339–47. BS40 5DU, United Kingdom; fax: +44 (0)117 4. Oliveira RP, Galvao MA, Mafra CL, 9289505; email: [email protected] Chamone CB, Calic SB, Silva SU, et al.

Community studies detected ESBL in the evaluat- antibiotics was determined by the ed population (1,2). We performed disk-diffusion test, following recom- Transmission of three survey studies to determine the mendations of the National Extended-Spectrum incidence of Committee for Clinical Laboratory β-Lactamase strains producing ESBLs in the stools Standards (4,5). The interpretative of outpatients attending our hospital. reading of the antibiogram was per- To the Editor: The spread of mul- The first study was performed during formed according to standard guide- tiresistant gram-negative in a 4-month period (February–May lines (4–6). The MICs of cefotaxime the general population is a problem of 2001), the second during a 3 month- and ceftazidime, with and without paramount importance, but the period (April–June 2002), and the clavulanic acid, were later determined responsible mechanisms are poorly third during 1 month (October 2002). by Etest (AB Biodisk, Solna, understood. Several studies have Stool samples were spread onto Sweden). Strains producing ESBL focused on β-lactam resistance in plates of MacConkey agar containing were defined as strains showing syn- Enterobacteriaceae isolated from 2 mg/L of cefotaxime. A colony of ergism between amoxicillin-clavulan- stools in healthy people, but they did each distinct morphotype was ana- ic acid and cefotaxime, ceftazidime, not specifically investigate the lyzed further. Species were identified cefepime, or aztreonam (4,5). extended-spectrum β-lactamases according to conventional methods All strains suspected of carrying a (ESBL). Furthermore, none of these (3). The susceptibility to β-lactam resistance pattern compatible with

1024 Emerging Infectious Diseases • Vol. 9, No. 8, August 2003 LETTERS hyperproduction of the chromosomal with other microorganisms (9–11). 5. National Committee for Clinical enzymes, as well as resistant strains Many questions remain unanswered Laboratory Standards. Supplemental tables: disk diffusion. Document M100-S10. without synergy, were disregarded. regarding the diffusion mechanisms Wayne (PA): The Committee; 2000. During the first period, 15 (2.1%) of of this resistance in the community. 6. Livermore DM. β-Lactamases in laboratory 707 outpatients were carriers of Confirmation of community-based and clinical resistance. Clin Microbiol Rev (14 patients) or transmission of ESBL would indicate 1995;8:557–84. 7. Sabaté M, Miró E, Navarro F, Vergés C, (1 patient) with a need for heightened vigilance and Aliaga R, Mirelis B, et al. Beta-lactamases ESBL. This percentage increased dur- further studies to determine the reser- involved in resistance to broad-spectrum ing the second period, when 17 voirs and vehicles for dissemination cephalosporins in Escherichia coli and (3.8%) of 454 outpatients were carri- of ESBL within the community. Klebsiella spp. clinical isolates collected between 1994 and 1996, in Barcelona ers of E. coli with ESBL, and again in (Spain). J Antimicrob Chemother the third period, when 12 (7.5%) of Beatriz Mirelis,*† Ferran Navarro,*† 2002;49:989–97. 160 were carriers of E. coli (11 Elisenda Miró,* Raul Jesús Mesa,* 8. Hernández JR, Pascual A, Cantón R, patients) or (1 Pere Coll,*† and Guillem Prats*† Martínez-Martínez L, Grupo de Estudio de Infección Hospitalaria (GEIH). Escherichia *Hospital de la Santa Creu i Sant Pau, patient) with ESBL. Characterization coli y productores Barcelona, Spain; and †Universitat of the different ESBL isolated during de betalactamasas de espectro extendido en Autònoma de Barcelona, Barcelona, Spain the three study periods is in process. hospitales españoles (Proyecto GEIH- Although Klebsiella pneumoniae car- BLEE 2000). Enferm Infecc Microbiol Clin References 2003;21:77–82. rying ESBL has been detected in our 9. Chambers HF. The changing epidemiology hospital (7), as well as in other hospi- 1. Briñas L, Zarazaga M, Saenz Y, Ruiz- of Staphylococcus aureus? Emerg Infect tals in Barcelona (8), no ESBL-pro- Larrea F, Torres C. β-Lactamases in ampi- Dis 2001;8:178–82. cillin-resistant Escherichia coli isolates ducing K. pneumoniae strains were 10. Garau J, Xercavins M, Rodríguez- from foods, humans, and healthy animals. Carballeira M, Gómez-Vera JR, Coll I, identified in this survey. Antimicrob Agents Chemother Vidal D, et al. Emergence and dissemina- Although we did not disregard 2002;46:3156–63. tion of quinolone-resistant Escherichia coli either the patients’ previous treatment 2. Österblad M, Hakanen A, Manninen R, in the community. Antimicrob Agents Leistevuo T, Peltonen R, Meurman O, et al. with antibiotics or previous hospital- Chemother 1999;43:2736–41. A between-species comparison of antimi- 11. Tomasz A. New faces of an old : ization, these patients came to the crobial resistance in enterobacteria in fecal emergence and spread of multidrug-resist- hospital from the community carrying flora. Antimicrob Agents Chemother ant Streptococcus pneumoniae. Am J Med strains that express ESBL. Moreover, 2000;44:1479–84. 1999;107:55S–62S. 3. Murray P, Baron E, Pfaller M, Tenover F, during these three periods we Yolken R. Manual of clinical microbiology. Address for correspondence: Beatriz Mirelis, observed a significant increase in the 7th ed. Washington: American Society for frequency of ESBL carriers (from Microbiology; 1999. Departament de Microbiologia, Hospital de la 2.1% to 7.5%; p<0.005). These data 4. National Committee for Clinical Santa Creu i Sant Pau, Av. Sant Antoni Laboratory Standards. Performance stan- MªClaret, 167, 08025 Barcelona, Spain; fax: 34 suggest that the community could be a dards for antimicrobial disk susceptibility 93 2919070; email: [email protected] reservoir for these enzymes, as occurs test. Document M2-A7. 7th ed. Wayne (PA): The Committee; 2000.

Polymyxin- ance rates to carbapenems have (7). In addition, the disk diffusion increased, reaching rates approxi- technique was reported to be an unre- Resistant mately 12% or higher in some liable method for evaluating the sus- Acinetobacter spp. Brazilian hospitals (1,3,4). Thus, ceptibility to polymyxins (8). Since Isolates: What Is more toxic agents such as polymyxins Acinetobacter clinical specimens have been used as alternative thera- exhibiting high MICs for polymyxins Next? peutic drugs against multidrug-resist- (MIC, 8–32 µg/mL) were recently To the Editor: In Brazilian hospi- ant Acinetobacter infections (5,6). detected, we searched for the frequen- tals, Acinetobacter spp. has been an The clinical use of polymyxins has cy of occurrence of Acinetobacter important etiologic agent of nosoco- been based on antimicrobial suscepti- spp. strains exhibiting reduced sus- mial infections, mainly bility results and previous clinical ceptibility to polymyxin B among 100 (1–3). In general, ampicillin/sulbac- experience. However, the National bloodstream isolates of Acinetobacter tam and carbapenems remain the last Committee for Clinical Laboratory spp. (8). The bacterial isolates were therapeutic options for treatment of Standards (NCCLS) documents do consecutively collected between such infections (3,4). However, resist- not currently provide interpretative September 1999 and December 2000 criteria for the testing of polymyxins from a tertiary Brazilian hospital,

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