G. Prats

Antibiotic resistance trends in enteropathogenic bacteria isolated in 1985-1987 and 1995-1998 in Barcelona.

ABSTRACT Trends in resistance to antimicrobial agents used for therapy have been evaluated with 3,797 enteropathogenic bacteria,Campylobacter, Salmonella,Shigella, and Yersinia, between 1985–1987 and 1995–1998. The greater increase in the rate of resistance was observed in Campylobacter jejuni for quinolones (from 1 to 82%) and tetracycline (from 23 to 72%) and in gastroenteric salmonellae for ampicillin (from 8 to 44%), chloramphenicol (from 1.7 to 26%), and trimethoprim-sulfamethoxazole and nalidixic acid (from less than 0.5 to 11%). Multidrug resistance was detected in several Salmonella serotypes. In the 1995–1998 period, 76% of Shigella strains were resistant to trimethoprim-sulfamethoxazole, 43% were resistant to ampicillin, and 39% were resistant to chloramphenicol. Seventy-two percent ofYersinia enterocolitica O3 strains were resistant to streptomycin, 45% were resistant to sulfonamides, 28% were resistant to trimethoprim-sulfamethoxazole, and 20% were resistant to chloramphenicol.

Cloning and Sequence of the Gene Encoding a Novel Cefotaxime-Hydrolyzing β-Lactamase (CTX-M-9) from Escherichia coli in Spain

ABSTRACT A new CTX-M-type β-lactamase (CTX-M-9) has been cloned from a clinical cefotaxime-resistant Escherichia coli strain. Despite the close identity that exists between the CTX-M-9 and Toho-2 β-lactamases (88%), the 35 amino acids located between residues Ala-185 and Ala-219 are totally different in both enzymes. Outside of this region there are only six amino acids substitutions between both proteins.

First Detection of a Carbapenem-Hydrolyzing Metalloenzyme in Two Enterobacteriaceae Isolates in Spain

ABSTRACT Two strains of Enterobacteriaceae, Escherichia coli and Klebsiella pneumoniae, producing VIM-1 were isolated for the first time in Spain. In both strains, blaVIM-1 was found to be carried on a gene cassette inserted into a class 1 integron. The blaVIM-1-containing integron was located on a transferable plasmid.

Phage Types and Genotypes of Shiga Toxin-Producing Escherichia coli O157:H7 Isolates from Humans and Animals in Spain: Identification and Characterization of Two Predominating Phage Types (PT2 and PT8)

ABSTRACT Phage typing and DNA macrorestriction fragment analysis by pulsed-field electrophoresis (PFGE) were used for the epidemiological subtyping of a collection of Shiga toxin-producing Escherichia coli (STEC) O157:H7 strains isolated in Spain between 1980 and 1999. Phage typing distinguished a total of 18 phage types among 171 strains isolated from different sources (67 humans, 82 bovines, 12 ovines, and 10 beef products). However, five phage types, phage type 2 (PT2; 42 strains), PT8 (33 strains), PT14 (14 strains), PT21/28 (11 strains), and PT54 (16 strains), accounted for 68% of the study isolates. PT2 and PT8 were the most frequently found among strains from both humans (51%) and bovines (46%). Interestingly, we detected a significant association between PT2 and PT14 and the presence of acute pathologies. A group of 108 of the 171 strains were analyzed by PFGE, and 53 distinct XbaI macrorestriction patterns were identified, with 38 strains exhibiting unique PFGE patterns. In contrast, phage typing identified 15 different phage types. A total of 66 phage type-PFGE subtype combinations were identified among the 108 strains. PFGE subtyping differentiated between unrelated strains that exhibited the same phage type. The most common phage type-PFGE pattern combinations were PT2-PFGE type 1 (1 human and 11 bovine strains), PT8-PFGE type 8 (2 human, 6 bovine, and 1 beef product strains), PT2-PFGE subtype 4A (1 human, 3 bovine, and 1 beef product strains). Nine (29%) of 31 human strains showed phage type-PFGE pattern combinations that were detected among the bovine strains included in this study, and 26 (38%) of 68 bovine strains produced phage type-PFGE pattern combinations observed among human strains included in this study, confirming that cattle are a major reservoir of strains pathogenic for humans. PT2 and PT8 strains formed two groups which differed from each other in their motilities, stx genotypes, PFGE patterns, and the severity of the illnesses that they caused.

Dissemination of extended-spectrum β-lactamase-producing bacteria: the food-borne outbreak lesson

OBJECTIVES Commensal and opportunistic bacteria producing extended-spectrum beta-lactamases (ESBL-PB) have undergone a broad and rapid spread within the general population; however, the routes of dissemination have not been totally elucidated. The aim of this study was to determine whether individuals involved in an outbreak of acute gastroenteritis, in addition to the enteropathogenic microorganism, share an ESBL-PB as indirect demonstration of its transmission from a common food source. METHODS From 2003 to 2004 in Barcelona, Spain, stool samples from 905 people involved in 132 acute gastroenteritis outbreaks and 226 food handlers related to the outbreaks were investigated. RESULTS In 31 outbreaks, 58 diners carrying one or more ESBL-PB were detected. In 10 outbreaks, two or more diners shared the same ESBL-PB, and in four of them, the strain was shared with the food handlers. CONCLUSIONS This study provides circumstantial evidence that foods can be a transmission vector for ESBL-PB, probably from two reservoirs, food animals and food handlers.

Mycobacterium xenopi Infections in the Acquired Immunodeficiency Syndrome

Abstract To the Editor:Several cases of infection due toMycobacterium xenopihave been reported (1, 2). This organism has been cultured frequently in samples from hot-water generators and storage ta...

Immunochemical localization of major hydatid fluid antigens in protoscoleces and cysts of Echinococcus granulosus from human origin

Summary Monospecitic rabbit an user a obtained through experimental immunization with previously purified proteins were used in the structural localization of two hydatid fluid antigens, antigen 5 and antigen B, in cyst membranes and protoscoleces of E. granulosus from human origin. The antigen‐antibody reaction was revealed by an avidin‐biotin‐peroxidase technique. Antigen 5 was not evident in the laminated membrane of the cyst wall, but it was associated with the germinal membrane of the cyst wall and brood capsules. The parenchyma of invaginated and evaginated protoscoleces was heavily labelled. The tegument, the calcareous corpuscles, the suckers and the hooks did not contain antigen 5. Degenerated protoscoleces were also labelled. Antigen B localization was essentially identical to antigen 5. but degenerated protoscoleces were not recognized by anti‐antigen B anliserum. Technical aspects and differences with previously published work arc discussed.

EVALUATION OF CULTURE TECHNIQUES FOR DIAGNOSIS OF CATHETER-RELATED SEPSIS IN CRITICALLY ILL PATIENTS

In a previous study we reported that culture of the external surface of the catheter tip alone using the semiquantitative culture technique seems to be the best method for diagnosing catheter-related septicemia in unselected populations. However, it is not clear whether these results can be extrapolated to non-bacteremic catheter-related sepsis. Furthermore, this question should be studied independently in highly selected populations such as critically ill patients. We now present the results of a prospective study evaluating the usefulness of culture of both the external and intralumenal surfaces of intravascular catheters in critically ill patients with suspected catheter-related sepsis.

Resistencia a quinolonas y betalactámicos en Salmonella enterica, y su relación con mutaciones en las topoisomerasas, alteraciones en la permeabilidad celular y expresión de un mecanismo de expulsión activa

Antecedentes Se ha estudiado la implicacion de distintos mecanismos de resistencia a quinolonas y betalactamicos en cepas de Salmonella enterica resistentes a ambos grupos de antimicrobianos aisladas secuencialmente de pacientes tratados con fluoroquinolonas durante un largo periodo. Metodos La clonalidad de las distintas cepas se determino mediante serotipado y macrorrestriccion genomica en campo pulsante. En el estudio de la sensibilidad se calcularon los valores de la CIM a betalactamicos, quinolonas, cloranfenicol y tetraciclina. Para la caracterizacion de los mecanismos de resistencia implicados se descarto la presencia de betalactamasas mediante tecnica colorimetrica; se secuenciaron las regiones determinantes de resistencia a quinolonas de los genes gyrA, gyrB, parC y parE, realizandose estudios de complementacion para evaluar la importancia de las mutaciones encontradas; se obtuvo el perfil de proteinas de la membrana externa, se determino el efecto de fenil-arginil-naftilamida (FAN, 20 mg/l) en la CIM de varias quinolonas y se midio la acumulacion de norfloxacino en presencia y en ausencia de un inhibidor metabolico. Resultados Se han detectado mutaciones en gyrA (Asp87 → Gly; Ser83 → Phe; Asp87 → Lys), gyrB (Ser463 → Phe) y parC (Glu84 → Gly); alteraciones en la expresion de las porinas (disminucion de la porina equivalente a OmpF en Escherichia coli) y tanto en una cepa clinica como en un mutante obtenido in vitro, se observo la expresion de un mecanismo de expulsion activa de norfloxacino. En presencia de FAN las CIM de acido nalidixico disminuyeron (salvo en una cepa) de 4 a 32 veces, las de pefloxacino disminuyeron 4-16 veces en 5 de 9 cepas evaluadas, y las de norfloxacino y ciprofloxacino no variaron o lo hicieron en una sola dilucion. Conclusion La resistencia a quinolonas se expresa por la combinacion de mutaciones en los genes que codifican las topoisomerasas, alteraciones de la permeabilidad y una expulsion activa. Estos dos ultimos mecanismos tambien contribuirian a la disminucion de la sensibilidad a betalactamicos.

Ultrastructural localization of major hydatid fluid antigens in brood capsules and protoscoleces of Echinococcus granulosus of human origin

Monospecific rabbit antisera obtained through experimental immunization with previously purified proteins were used in the ultrastructural localization of two hydatid fluid antigens, in brood capsules and protoscoleces of Echinococcus granulosus of human origin. The antigen‐antibody reaction was revealed by a colloidal gold based method. Reaction was evident in the connective region of the germinal membrane and in the parenchyma of the protoscoleces. Both antigen 5 and antigen B were located in the interstitial material between the parenchymal cells and precisely associated with disorganized areas. The brood capsule wall and the brood capsule contents, the tegument of the protoscoleces, the parenchymal cells, the muscle cells, the calcareous corpuscles and the hooks did not contain antigen 5 or antigen B. Label was not observed in the lumen of the collecting ducts or in the flame cells, although antigen 5 was evident in the periluminal cytoplasm. The origin of the antigens and their release are discussed.