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Publications (58)
Rapidly growing non-tuberculosis mycobacteria are a rare cause of bacterial endocarditis. During the last decades, there has been an increase in infections due to rapidly growing mycobacteria, especially after trauma and postoperative procedures, both localized and disseminated, as well as nosocomial outbreaks due to contamination of medical equipm...
La infección por VIH incrementa la posibilidad de contraer tuberculosis; el riesgo resulta mayor para las formas extrapulmonares y dentro de estas, la meníngea. La infección por VIH no modifica las manifestaciones neurológicas pero disminuye significativamente la supervivencia. El método molecular GeneXpert MTB/RIF (CEPHEID, USA), implementado en 2...
The aim of this review is to present an update on the susceptibility of viridans group streptococci (VGS) to β-lactam antimicrobials, with emphasis on the Argentinean scenario. VGS are a heterogeneous group including five groups of species, each one exhibiting peculiar susceptibility patterns to penicillin (PEN). Species of the Streptococcus mitis...
Streptococcus pneumoniae is an important causal agent of pneumonia, meningitis, sepsis, bacteremia, and otitis media. Penicillin resistance rates in S. pneumoniae have remained stable in Argentina in the last years. In the late ‘90s more isolates with MIC of penicillin ≥2 μg/ml were observed; however, their frequency has decreased in recent years....
ABSTRACT
Objectives: In this study, we evaluated a rapid and simple protocol for direct identification of microorganisms
with Matrix-Assisted Laser Desorption/Ionization Time of Flight, Mass Spectrometry (MALDI-TOF MS) after
a short incubation in solid medium (3 to 5h).
Methods:We have examined a total of 1101 positive blood culture bottles from 78...
Abstract Enterococci are intrinsically resistant to several antimicrobial classes and show agreat ability to acquire new mechanisms of resistance. Resistance to �-lactam antibiotics isa major concern because these drugs either alone or in combination are commonly used forthe treatment of enterococcal infections. Ampicillin resistance, which is rare...
Rapidly growing non-tuberculosis mycobacteria are a rare cause of bacterial endocarditis. During the last decades, there has been an increase in infections due to rapidly growing mycobacteria, mainly after trauma and post-surgical procedures, both localized and disseminated, as well as nosocomial outbreaks due to contamination of medical equipment....
Enterococci are intrinsically resistant to several antimicrobial classes and show a great ability to acquire new mechanisms of resistance. Resistance to β-lactam antibiotics is a major concern because these drugs either alone or in combination are commonly used for the treatment of enterococcal infections. Ampicillin resistance, which is rare in En...
Group A (GAS), B (GBS), C (GCS) and G (GGS) β-hemolytic streptococci are important human pathogens. They cause infections of different severity and frequency. Nowadays, after 70 years of use, penicillin is still universally active against GAS, GCS and GGS. However, therapeutic failures have been recorded in 2-28% of pharyngitis cases (median: 12%)...
Case presentation:
We describe a case of bacteremia caused by M. hominis in a previously healthy woman after uterine curettage due to incomplete abortion. M. hominis could be an underestimated cause of bacteremia in immunocompetent patients. Mycoplasma organisms have fastidious growth requirements, are often difficult to culture on a cell-free med...
Background
Globally, Latin America ranks third among regions with most cases of AIDS related cryptococcal meningitis. In 2009, a lateral flow immunoassay (LFA) for the detection of cryptococcal antigen (CrAg) was developed as a potential point-of-care test for diagnosis of cryptococcal infection. In 2011 World Health Organizations recommended on Cr...
Bacteria in the genus Leuconostoc are very infrequent opportunistic pathogens. We report a case of
meningitis due to Leuconostoc mesenteroides sub sp. mesenteroides associated with central nervous
system tuberculosis in a patient with advanced HIV/AIDS infection.
La identificación microbiológica por espectrometría de masas (EM) ha revolucionado el campo de la microbiología clínica. La tecnología MALDI-TOF ha sido desarrollada para la aplicación en el laboratorio clínico, por las empresas Shimadzu (BioMerieux) y Bruker (Becton Dickinson). La Red Nacional de Bacteriología ha evaluado el desempeño de MALDI-TOF...
La infección por VIH incrementa la posibilidad de contraer tuberculosis; el
riesgo resulta mayor para las formas extrapulmonares y dentro de estas, la
meníngea. La infección por VIH no modifica las manifestaciones neurológi-
cas pero disminuye significativamente la supervivencia. El método molecu-
lar GeneXpert MTB/RIF (CEPHEID, USA), implementad...
Rapid identification of microorganisms is critical in hospitalized infected patients. Blood culture is currently the gold standard for detecting and identifying microorganisms causing bacteremia or sepsis. The introduction of mass spectrometry by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF MS) in microbiology laboratories,...
Here we report that the genetic structure of Tn1331 remained conserved in Argentina since 1989 to 2013 (72/73), except for the plasmid-borne Tn1331-like transposon Tn6238 containing a new aac(6' )-Ib-cr allele recovered from a colistin resistant Klebsiella pneumoniae clinical isolate. Bioinformatic analysis of aac(6' )-Ib-like gene cassettes sugges...
Unlabelled:
We report the first case in Argentina of community-acquired methicillin-resistant Staphylococcus aureus with intermediate susceptibility to vancomycin and nonsusceptibility to daptomycin.
Case report:
A male patient with a history of chronic renal failure on hemodialysis and hip fracture osteosynthesis was admitted to hospital for pe...
We report the first case in Argentina of community-acquired methicillin-resistant Staphylococcus aureus with intermediate susceptibility to vancomycin and nonsusceptibility to daptomycin.Case report: A male patient with a history of chronic renal failure on hemodialysis and hip fracture osteosynthesis was admitted to hospital for persistent febrile...
Eighty one rectal swabs (RS) were cultured on CHROMagar KPC and the CDC method. Of the 81 samples, 9 were positive for KPC-producing Klebsiella pneumoniae on CHROMagar KPC, and 6 for the CDC method. CHROMagar KPC had two false positive (FP) results: 1 K. pneumoniae and 1 Acinetobacter sp. FP results on the CDC method were: 25 Acinetobacter spp., 2...
Multiple transposons, integrons and carbapenemases were found in Klebsiella pneumoniae colistin-resistant isolates as well as a genomic resistance island of the AbaR type in Acinetobacter baumannii colistin-resistant isolates from different hospitals from Buenos Aires City. PFGE analysis showed a polyclonal dissemination of antimicrobial resistance...
CHROMagar KPC. Comparison with the method proposed by the Centers for Disease Control and Prevention (CDC, USA) for rectal screening and evaluation of false positive results. Eighty one rectal swabs (RS) were cultured on CHROMagar KPC and the CDC method. Of the 81 samples, 9 were positive for KPC-producing Klebsiella pneumoniae on CHROMagar KPC, an...
Streptococcus agalactiae es una causa importante de morbimortalidad en mujeres embarazadas y neonatos en todo el mundo. El objetivo del presente trabajo fue determinar la utilidad del medio cromogénico chromID Strepto B de bioMérieux para detectar S. agalactiae en embarazadas cuando la muestra es sembrada directamente en dicho medio o después del e...
Streptococcus agalactiae is a significant worldwide cause of morbidity and mortality in pregnant women and their newborn infants. The objective of this work was to determine the usefulness of bioMerieux chromogenic medium chromID Strepto B (CR) for detecting S. agalactiae in pregnant women from the selective Todd-Hewitt broth (sel-THB ) against the...
From the blood culture of an HIV-positive patient with a febrile syndrome (CD4 count 385 cells/microL and viral load nondetectable), Brucella canis was isolated. The patient was presumptively infected from his dogs, which tested positive, and showed good outcome after the therapy with doxycycline-ciprofloxacin, and the HIV infection would seem not...
Tigecycline is a new antibiotic currently used in healthcare environments where multidrug resistance is prominent. Because there is a constant potential for resistance to emerge, survey studies are needed.
Isolates collected in 20 clinical laboratories from 4 states of Argentina between November 2005 and October 2006 were tested using the disk diff...
Background: Nocardia spp. are agents of systemic, respiratory and skin infections particularly in immunocompromised.Therapeutic efficacy in patients may depend on species identity and on in vitro susceptibility studies.The aim of this study was to assess the species distribution of Nocardia isolates in Argentina and to investigate whether the diffe...
Presentamos el caso de un hombre de 68 años que ingresó por mareos y sensación de pérdida de la conciencia. El examen clínico reveló una temperatura de 37.5 °C y un soplo de regurgitación mitral. El ecocardiograma mostró una insuficiencia mitral grave con dilatación de las cavidades izquierdas, y el ecocardiograma transesofágico una vegetación en l...
In order to study the enzymatic carbapenem resistance mechanisms in Acinetobacter baumannii isolates from Argentina, we performed molecular characterization on 41 epidemiologically unrelated strains isolated from 1995 to 2006 with diminished susceptibilities to imipenem and meropenem.
Acinetobacter baumannii isolates were identified with the ARDRA...
We present the clinical case of a man of 68 years who was admitted for dizziness and sensation of loss of conscience. The clinical examination revealed a body temperature of 37.5 degrees C and a murmur of mitral regurgitation. The echocardiogram showed a severe mitral regurgitation and left cavitie's dilatation; transesophageal echocardiogram showe...
La coinfección con el virus de hepatitis C (HCV) en individuos infectados con HIV está asociada con una mayor incidencia de injuria y descompensación hepática, y un menor tiempo de supervivencia respecto de la población mono-infectada por HIV. Mientras que diferentes estudios de prevalencia de la coinfección HIV/HCV se han llevado a cabo en Estados...
Trichosporon asahii is an opportunistic fungus considered the leading etiologic agent of trichospornosis, a disease that causes great morbidity/mortality among affected patients. The identification of the etiologic agent is generally obtained through physiological and morphological studies. Molecular investigations, such as species-specific primers...
To report a case of subretinal abscess due to Nocardia farcinica resistant to trimethoprim-sulfamethoxazole in a patient with systemic lupus erythematosus on immunosuppressive therapy.
Observational case report.
We retrospectively studied the medical record of a patient with nocardiosis.
The microorganism disseminated from the lungs (pneumonia) to...
Oesophageal candidiasis is an epithelial infection which requires an immune deficiency. C. albicans is commonly the cause, although other species may also be responsible. Resistance to fluconazole, drug of choice for treatment, is an emerging problem. The objectives of the current paper were: to determine the frequency of oesophageal candidiasis in...
Erythromycin (ERY) resistance in Streptococcus pyogenes has recently emerged as a problem of growing concern all through the world. We are presenting the comparison of results of the continuous surveillance of erythromycin resistance in S. pyogenes performed since 1989 in the Hospital de Pediatría J.P. Garrahan of Buenos Aires City, with independen...
We evaluated different methods for the routine identification of medically important yeasts. A total of 150 clinical isolates: 25 C. albicans, 25 C. tropicalis, 25 C. glabrata, 25 C. parapsilosis, 8 C. guilliermondii, 11 C. krusei and 31 Cryptococcus neoformans were tested by Yeast Biochemical Card bioMerieux Vitek (YBC), CHROMagar Candida (CHR). T...
Fifteen episodes of Mycobacterium tuberculosis laboratory cross-contamination suspected between 1996 and 2001 at 6 laboratories in Buenos Aires City and suburbs were investigated by IS6110 RFLP. Thirteen episodes were confirmed. Even though BACTEC 460 produced the highest number of confirmed episodes in a single laboratory, the most extended one oc...
A bloodstream infection due to Candida haemulonii afflicting a patient with fever and a medical history of megaloblastic anemia is reported. The clinical isolate was misidentified
by the API 20C and VITEK identification systems. The results of susceptibility tests showed that the MIC of amphotericin B
for C. haemulonii was 4 μg/ml. Additional susce...
Infection with Cryptococcus neoformans is an increasing problem in immunocompromised patients, particularly those with acquired immune deficiency syndrome (AIDS). Amphotericin B and fluconazole are currently acceptable therapies for cryptococcal meningitis; however, their effects remain suboptimal and recurrence or treatment failure is still a prob...
The in vitro activities of three antifungal drugs alone and in combination were evaluated against five isolates of Cryptococcus neoformans using time-kill curves (TKC). The isolates were from AIDS patients who had either died or had failed to show a clinical response during amphotericin B (AMB) treatment. AMB, fluconazole (FCZ) and flucytosine (5FC...
Histoplasmosis is a deep mycosis which is increasingly seen in HIV disease. It has emerged as a relatively common infection in Argentina, mainly in HIV-infected and other immunocompromised persons, and is often disseminated (DH).
The aim of this study was to describe 32 HIV-I-seropositive patients with AIDS who had DH, 21 of whom presented orofacia...
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...
Administration of either amikacin (1985) or gentamicin (1984, 1986-1991) as first-choice aminoglycoside did not decrease the high incidence of amikacin-resistant Serratia marcescens (ARSm) isolates responsible for nosocomial infections at the J.A. Fernández Hospital of Buenos Aires (42% in 1984, 31% in 1985 and 41% in 1987, differences not signific...
During 17 months, 73 HIV-positive patients with diarrhea lasting at least for 14 days, were studied prospectively. The patients had stool specimen examinations negative for enteric pathogens, or positive for one of them, but with no response to specific treatment. All patients were subcomitted to digestive endoscopy and biopsies were taken for micr...
We evaluated an agar disc diffusion test for the detection of high-level (> or = 2000 mg/L) and moderately high-level resistance to gentamicin (MIC, > or = 128- < or = 1024 mg/L) and streptomycin (MIC, > or = 256- < or = 1024 micrograms/ml) with 70 clinical isolates of Enterococcus faecium. Results obtained using disks containing 120 micrograms gen...
Serovars of Salmonella resistant to ampicillin, third-generation cephalosporins and aminoglycosides but sensitive to chloramphenicol, cefoxitin and ceftibuten emerged in one pediatric hospital of Buenos Aires. All isolates expressed AAC(6')-I and AAC(3)-V enzyme activities, making them resistant to all aminoglycosides marketed in Argentina by the t...
Administration of either gentamicin or amikacin induced an increase in the number of amikacin-resistant (AR) isolates of certain Enterobacteriaceae and Acinetobacter species in a hospital in Buenos Aires. A total of 127 AR isolates was selected to study the molecular mechanisms of resistance involved. The aac(6')-Ic gene was found by dot-blot hybri...
The aim of the present report was to study microbiological aspects, laboratory diagnosis and management of community-acquired bacterial acute pneumoniae, with special considerations to analysis of the most frequent etiologic agents isolated in the city of Buenos Aires. In 3213 samples of sputum from ambulatory immunosufficient or immunosuppressed p...
A total of 103 patients (P) with infectious endocarditis (IE) were treated during the period 1982-1993; 72% of them were male. Mean age was 46.4 (SD 19.7). Eighteen patients were intravenous drug addicts (D) (17.5%). The first case of drug addiction in the IE group was seen in 1986; since then, there was a steady increase of this condition, reachin...
Plasmid pPG1 from Staphylococcus aureus coding for ampicillin (Apr), gentamicin (Gmr) and amikacin (Akr) resistance was transformed into Escherichia coli. Transformation efficiency was about 2 x 10(3) transformants/micrograms of plasmid DNA. The plasmids present in the E. coli transformants were identical to pPG1 according to their restriction patt...
