[Evaluation of API Coryne System, version 2.0, for diphteroid gram-positive rods identification with clinical relevance]. / Evaluación del sistema API coryne, versión 2.0, para la identificación de bacilos gram-positivos difteroides de importancia clínica.

The ability of the API Coryne system, version 2.0, to identify 178 strains of gram-positive rods was evaluated. Seventy eight isolates belonged to genus Corynebacterium and one hundred to related genera, all strains were isolated from clinical samples at the Laboratory of Bacteriology, Hospital de Clínicas José de San Martin (UBA) between 1995 and 2004. The isolates were identified according to von Graevenitz and Funke's scheme. One hundred and sixty two out of 178 strains (91%) were correctly identified at genus and species level (IC95 = 85.6-94.6), in 44 of them (24.7%) additional tests were needed to final identification. Sixteen strains (9%) were not correctly identified (IC95 = 5.4-14.4); none of the 178 strains remained unidentified. The API Coryne system, version 2.0, is useful to identify the majority of Cory-nebacterium species with clinical relevance: Corynebacterium jeikeium, Corynebacterium urealyticum, Corynebacterium striatum, Corynebacterium pseudodiphtheriticum, Corynebacterium amycolatum and related species such as Arcanobacterium haemolyticum, Dermabacter hominis, Listeria monocytogenes, among others. Nevertheless for yellow-pigmented diphteroid gram-positive rods (Aureobacterium spp., Leifsonia aquatica, Microbacterium spp. and Cellulomonas spp.) and for acid fast gram-positive rods (Rhodococcus, Gordonia, Tsukamurella and Nocardia) the identification usefulness the system is limited.

Phenotypic and genotypic characterization of macrolide resistant Streptococcus pneumoniae recovered from adult patients with community-acquired pneumonia in an Argentinian teaching hospital.

Streptococcus pneumoniae isolates (n = 262) were recovered from adult patients with community-acquired pneumonia. Erythromycin-resistance levels increased from 9% (1997-1998) to 16% (2000-2002). Sampling for resistance mechanisms prevalent within 19 erythromycin-resistant S. pneumoniae showed mef(E) in 13/19 isolates while 4/19 carried the erm(B) gene (3/19 cMLS(B) and 1/19 iMLS(B) phenotype). MIC ranges for erythromycin and clindamycin were 0.5-16 mg/l and <0.008-0.063 mg/l for the M phenotype, 128-512 mg/l and 128-256 mg/l for the cMLS(B) phenotype, and 4 and <0.008 mg/l for the iMLS(B) phenotype. This is the first report studying the prevalence of macrolide resistance determinants in S. pneumoniae in our country.

Neumonia por Legionella pneumophila. Experiencia en un Hospital Universitario de Buenos Aires / Pneumonia due to Legionella pneumophila. Experience gathered in a University Hospital in Buenos Aires

Legionnaires' disease is a well recognized cause of community acquired pneumonia (CAP) all around the world. In Latin America its incidence remains unknown. This study analyzed a cohort of 9 patients with CAP due to Legionella pneumophila observed from 1997 to 2001, in the Hospital de Clínicas José de San Martin, University of Buenos Aires. Clinical history included recent illnesses, work exposure, physical exam, prior antibiotic use and severity of illness criteria. None of the 9 patients had a history of recent travels, and 4 of them required admission in intensive care unit (ICU). Seven patients had a cigarette smoking history, four of them also had COPD, and one patient had a non-Hodgkin lymphoma. This study confirms the low specificity of clinical and general laboratory criteria to predict this etiology. Legionella isolation is difficult, and serological testing allows retrospective diagnosis but takes several weeks, while urinary antigen test gives a bed-side diagnosis. When Legionella appears in isolated cases, as happens in Argentina, it should be necessary to have a high index of suspicion to successfully arrive at an etiological diagnosis. Legionella pneumophila is a pathogen causing CAP in our area. A surveillance should be established preferably focused on selected populations including severe CAP, immunocompromised hosts and patients with chronic obstructive pulmonary disease.

La enfermedad de los legionarios es una causa de neumonía adquirida en la comunidad (NAC)reconocida en todo el mundo. En Latinoamérica su incidencia es desconocida. En este estudiose analizó a 9 pacientes con NAC por Legionella pneumophila atendidos entre 1997 y 2001 en el Hospital deClínicas José de San Martín de la Universidad de Buenos Aires. Se registraron datos de antecedentes, enfermedad actual, contactos, exposición laboral, examen físico, pruebas de laboratorio y uso previo de antibióticos, y se tomó en cuenta la presencia de criterios de gravedad. Nueve pacientes presentaron diagnóstico de NAC por Legionella, ninguno refirió antecedentes de viajes recientes; cuatro de ellos debieron ser internados en unidades de cuidado intensivo. Siete pacientes tenían antecedentes de tabaquismo, 4 tenían EPOC y un paciente linfoma no-Hodgkin. Nuestra casuística corrobora la baja especificidad de la clínica y estudios complementarios para predecir esta etiología. El aislamiento de Legionella es dificultoso, la seroconversión permite eldiagnóstico retrospectivo y requiere plazos prolongados y el antígeno urinario aporta un diagnóstico inmediato.Cuando la legionelosis aparece en casos aislados, como ocurriría en Argentina, si no se piensa en esta etiologíano se llegará al diagnóstico. Legionella pneumophila es un patógeno de NAC en nuestro medio, debe buscarsemejor, particularmente en pacientes graves, inmunodeprimidos y en fumadores con enfermedad pulmonarobstructiva crónica (EPOC).

Neumonia por Legionella pneumophila. Experiencia en un Hospital Universitario de Buenos Aires / Pneumonia due to Legionella pneumophila. Experience gathered in a University Hospital in Buenos Aires

Legionnaires disease is a well recognized cause of community acquired pneumonia (CAP) all around the world. In Latin America its incidence remains unknown. This study analyzed a cohort of 9 patients with CAP due to Legionella pneumophila observed from 1997 to 2001, in the Hospital de Clínicas José de San Martin, University of Buenos Aires. Clinical history included recent illnesses, work exposure, physical exam, prior antibiotic use and severity of illness criteria. None of the 9 patients had a history of recent travels, and 4 of them required admission in intensive care unit (ICU). Seven patients had a cigarette smoking history, four of them also had COPD, and one patient had a non-Hodgkin lymphoma. This study confirms the low specificity of clinical and general laboratory criteria to predict this etiology. Legionella isolation is difficult, and serological testing allows retrospective diagnosis but takes several weeks, while urinary antigen test gives a bed-side diagnosis. When Legionella appears in isolated cases, as happens in Argentina, it should be necessary to have a high index of suspicion to successfully arrive at an etiological diagnosis. Legionella pneumophila is a pathogen causing CAP in our area. A surveillance should be established preferably focused on selected populations including severe CAP, immunocompromised hosts and patients with chronic obstructive pulmonary disease.(AU)

La enfermedad de los legionarios es una causa de neumonía adquirida en la comunidad (NAC)reconocida en todo el mundo. En Latinoamérica su incidencia es desconocida. En este estudiose analizó a 9 pacientes con NAC por Legionella pneumophila atendidos entre 1997 y 2001 en el Hospital deClínicas José de San Martín de la Universidad de Buenos Aires. Se registraron datos de antecedentes, enfermedad actual, contactos, exposición laboral, examen físico, pruebas de laboratorio y uso previo de antibióticos, y se tomó en cuenta la presencia de criterios de gravedad. Nueve pacientes presentaron diagnóstico de NAC por Legionella, ninguno refirió antecedentes de viajes recientes; cuatro de ellos debieron ser internados en unidades de cuidado intensivo. Siete pacientes tenían antecedentes de tabaquismo, 4 tenían EPOC y un paciente linfoma no-Hodgkin. Nuestra casuística corrobora la baja especificidad de la clínica y estudios complementarios para predecir esta etiología. El aislamiento de Legionella es dificultoso, la seroconversión permite eldiagnóstico retrospectivo y requiere plazos prolongados y el antígeno urinario aporta un diagnóstico inmediato.Cuando la legionelosis aparece en casos aislados, como ocurriría en Argentina, si no se piensa en esta etiologíano se llegará al diagnóstico. Legionella pneumophila es un patógeno de NAC en nuestro medio, debe buscarsemejor, particularmente en pacientes graves, inmunodeprimidos y en fumadores con enfermedad pulmonarobstructiva crónica (EPOC).(AU)

[Evaluation of API 20 NE (version 6.0) in rare Gram-negative non-glucose-fermenting bacilli]. / Evaluación de API 20 NE (versión 6.0) en bacilos gram-negativos no fermentadores de glucosa infrecuentes.

The ability of the API 20 NE method (6.0 version, bio-Mérieux, Marcy L'Etoile, France) to identify 188 strains of gram negative nonfermentative bacilli (NFB) was evaluated (Fenazinic pigment producing Pseudomonas aeruginosa and Acinetobacter spp. were excluded). These were isolated from patients treated at the Hospital de Clínicas José de San Martín of the University of Buenos Aires during the period 1996-2001. Strains were identified according to the Schreckenberger P testing method. Out of 188 NFB strains, 175 (93.09%) were correctly identified by the API 20 NE method at the genus and species level (IC95 = 88.47-96.27) while 61 (32.45%) required additional testing for correct identification. Thirteen strains (6.91%; IC95 3.73-11.53) could not be correctly identified and none of them were classified as "non identified". The API 20 NE method is a practical, easy to handle, fast and useful system for the identification of NFB since conventional manual methods take longer and require many biochemical, enzymatic and physiological tests which are sometimes not available depending on the size and capability of the laboratory. Although it is easy to handle, the API 20 NE identification system must be interpreted by an expert microbiologist who must compare the results obtained by this system with the information provided by the distinctive cultures and mobility patterns of these organisms.

Evaluación de API 20 NE (versión 6.0) en bacilos gram-negativos no fermentadores de glucosa infrecuentes / [Evaluation of API 20 NE (version 6.0) in rare Gram-negative non-glucose-fermenting bacilli]

The ability of the API 20 NE method (6.0 version, bio-Mérieux, Marcy L’Etoile, France) to identify 188 strains of gram negative nonfermentative bacilli (NFB) was evaluated (Fenazinic pigment producing Pseudomonas aeruginosa and Acinetobacter spp. were excluded). These were isolated from patients treated at the Hospital de Clínicas José de San Martín of the University of Buenos Aires during the period 1996-2001. Strains were identified according to the Schreckenberger P testing method. Out of 188 NFB strains, 175 (93.09

) were correctly identified by the API 20 NE method at the genus and species level (IC95 = 88.47-96.27) while 61 (32.45

) required additional testing for correct identification. Thirteen strains (6.91

; IC95 3.73-11.53) could not be correctly identified and none of them were classified as [quot ]non identified[quot ]. The API 20 NE method is a practical, easy to handle, fast and useful system for the identification of NFB since conventional manual methods take longer and require many biochemical, enzymatic and physiological tests which are sometimes not available depending on the size and capability of the laboratory. Although it is easy to handle, the API 20 NE identification system must be interpreted by an expert microbiologist who must compare the results obtained by this system with the information provided by the distinctive cultures and mobility patterns of these organisms.

Evaluación de API 20 NE (versión 6.0) en bacilos gram-negativos no fermentadores de glucosa infrecuentes. / [Evaluation of API 20 NE (version 6.0) in rare Gram-negative non-glucose-fermenting bacilli]

The ability of the API 20 NE method (6.0 version, bio-Mérieux, Marcy LEtoile, France) to identify 188 strains of gram negative nonfermentative bacilli (NFB) was evaluated (Fenazinic pigment producing Pseudomonas aeruginosa and Acinetobacter spp. were excluded). These were isolated from patients treated at the Hospital de Clínicas José de San Martín of the University of Buenos Aires during the period 1996-2001. Strains were identified according to the Schreckenberger P testing method. Out of 188 NFB strains, 175 (93.09

) were correctly identified by the API 20 NE method at the genus and species level (IC95 = 88.47-96.27) while 61 (32.45

) required additional testing for correct identification. Thirteen strains (6.91

; IC95 3.73-11.53) could not be correctly identified and none of them were classified as [quot ]non identified[quot ]. The API 20 NE method is a practical, easy to handle, fast and useful system for the identification of NFB since conventional manual methods take longer and require many biochemical, enzymatic and physiological tests which are sometimes not available depending on the size and capability of the laboratory. Although it is easy to handle, the API 20 NE identification system must be interpreted by an expert microbiologist who must compare the results obtained by this system with the information provided by the distinctive cultures and mobility patterns of these organisms.

Cefotaxime-hydrolysing beta lactamases in Morganella morganii.

The frequency of enterobacterial isolates with high resistance to expanded-spectrum beta-lactam antibiotics (mainly cefotaxime or ceftriaxone) has increased notoriously in Argentina, mainly because of the spread of extended-spectrum beta-lactamases. The aim of this work was the study of extended-spectrum beta-lactamases in several Morganella morganii isolates with unusually high resistance to ceftriaxone. These strains produced at least two beta-lactamases, of apparent pIs of 5.4 and 8.2, molecular weight 23 000, well inhibited by clavulanate, compatible with a broad-spectrum beta-lactamase - perhaps TEM-1 - and an extended-spectrum beta-lactamase, respectively. The extended-spectrum beta-lactamase was identified as a CTX-M-type beta-lactamase - probably CTX-M-2 - by polymerase chain reaction, restriction profile analysis and DNA-DNA hybridisation. The remaining isolates studied produced either the broad-spectrum beta-lactamase plus the ubiquitous AmpC beta-lactamase (13 strains), or the AmpC beta-lactamase only (10 strains).

Argentinian collaborative study on prevalence of erythromycin and penicillin susceptibility in Streptococcus pyogenes. The Argentinian Streptococcus Study Group.

Two monthly studies on the prevalence of penicillin and erythromycin susceptibility of Streptococcus pyogenes were performed in May and October of 1994 in Argentina. A total of 58 centers from 27 cities participated in these studies. A total of 1072 isolates were tested by a diffusion method, although 595 isolates were tested both by the diffusion and an agar dilution method (n = 1767 isolates). No penicillin-resistant streptococci were found in our study (MIC100 = 0.03 microgram/ml). Only four isolates were confirmed as erythromycin resistant S. pyogenes (prevalence 0.14 and 0.28% in May and October 1994, respectively). Resistance in three isolates was due to an inducible mechanism, although in one strain a different phenotype was observed.

[Ceftizoxime: in vitro evaluation]. / Ceftizoxima: evaluación in vitro.

The effect of ceftizoxime, a new aminothiazolil-syn-methoxy-iminocephalosporin has been evaluated on 169 strains of Gram negative bacilli isolated from hospitalized patients and compared with that of cefotaxime and of ceftriaxone. The effect of these 3 cephalosporins and of cefalotin was also evaluated on 50 strains of staphylococcus. CIM50 of ceftizoximel was as follows: K. pneumoniae less than .032, aureus and S. epidermidis less than .2 CIM90 for the same species was: K. pneumoniae less than .25, E. coli less than .63, E. Cloacae and S. marcescens less than 8, S. aureus less than 32, S. epidermidis less than 16. The values obtained with cefotaxime and ceftriaxone were similar. Cefalotin was clearly more active on staphylococcus strains with CIM50 and CIM90 for both species of less than .25 and less than .2 respectively.

[Activity of cefpirome against bacteria isolated from hospitalized patients]. / Actividad de cefpiroma sobre bacterias aisladas de pacientes internados.

The activity of cefpirome (HR 810) was evaluated against 247 strains isolated from patients developing their infections while in a hospital in Buenos Aires. Its activity against Gram negative bacilli was compared with ceftriaxone, ceftazidime, cephalotin, piperacillin, amikacin, gentamicin and norfloxacin. In terms of MIC50 and MIC90 (mg/l) it was as follows: Klebsiella pneumoniae: less than 0.125, less than 2.0; Pseudomonas aeruginosa: less than 8, less than 16; Escherichia coli: less than 0.016, less than 0.063; Serratia marcescens: less than 0.063, less than 1.0; Enterobacter cloacae: less than 0.125, less than 1.0. Cefpirome was more active than the other cephalosporins against P. aeruginosa: at 16 mg/l, this drug inhibited 95% of strains versus 60% for ceftazidime and 32% for ceftriaxone. Activity of norfloxacine against Gram negative bacilli was similar to cefpirome, while piperacillin and the aminoglycosides were less active. Cefpirome was more active than cepahallotin against Streptococcus faecalis (2.0, 32) although less active than ampicillin, piperacillin, rifampicin and vancomycin. Against methicillin-susceptible Staphylococcus aureus (less than 0.25, less than 1.0) it was more active than cephalotin and the other drugs evaluated (piperacillin, erythromycin, chloranphenicol, aminogycosides). Like cephalotin, the activity of cefpirome against methicillin-resistant strains was variable (1.0, 32).

Ceftizoxima: evaluación in vitro. / [Ceftizoxime: in vitro evaluation]

The effect of ceftizoxime, a new aminothiazolil-syn-methoxy-iminocephalosporin has been evaluated on 169 strains of Gram negative bacilli isolated from hospitalized patients and compared with that of cefotaxime and of ceftriaxone. The effect of these 3 cephalosporins and of cefalotin was also evaluated on 50 strains of staphylococcus. CIM50 of ceftizoximel was as follows: K. pneumoniae less than .032, aureus and S. epidermidis less than .2 CIM90 for the same species was: K. pneumoniae less than .25, E. coli less than .63, E. Cloacae and S. marcescens less than 8, S. aureus less than 32, S. epidermidis less than 16. The values obtained with cefotaxime and ceftriaxone were similar. Cefalotin was clearly more active on staphylococcus strains with CIM50 and CIM90 for both species of less than .25 and less than .2 respectively.

Actividad de cefpiroma sobre bacterias aisladas de pacientes internados. / [Activity of cefpirome against bacteria isolated from hospitalized patients]

The activity of cefpirome (HR 810) was evaluated against 247 strains isolated from patients developing their infections while in a hospital in Buenos Aires. Its activity against Gram negative bacilli was compared with ceftriaxone, ceftazidime, cephalotin, piperacillin, amikacin, gentamicin and norfloxacin. In terms of MIC50 and MIC90 (mg/l) it was as follows: Klebsiella pneumoniae: less than 0.125, less than 2.0; Pseudomonas aeruginosa: less than 8, less than 16; Escherichia coli: less than 0.016, less than 0.063; Serratia marcescens: less than 0.063, less than 1.0; Enterobacter cloacae: less than 0.125, less than 1.0. Cefpirome was more active than the other cephalosporins against P. aeruginosa: at 16 mg/l, this drug inhibited 95

of strains versus 60

for ceftazidime and 32

for ceftriaxone. Activity of norfloxacine against Gram negative bacilli was similar to cefpirome, while piperacillin and the aminoglycosides were less active. Cefpirome was more active than cepahallotin against Streptococcus faecalis (2.0, 32) although less active than ampicillin, piperacillin, rifampicin and vancomycin. Against methicillin-susceptible Staphylococcus aureus (less than 0.25, less than 1.0) it was more active than cephalotin and the other drugs evaluated (piperacillin, erythromycin, chloranphenicol, aminogycosides). Like cephalotin, the activity of cefpirome against methicillin-resistant strains was variable (1.0, 32).