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Biomedical subjects

J Smayevsky

Publications and source records attributed to J Smayevsky.

At least 19 recordsLinked to original sources

Prospective evaluation of in-house polymerase chain reaction for diagnosis of mycobacterial diseases in patients with HIV infection and lung infiltrates.

SETTING: Rapid diagnosis of tuberculosis (TB) in AIDS is critical for optimal treatment to reduce mycobacterial dissemination, HIV-1 replication and mortality. The inadequate sensitivity of Ziehl-Neelsen staining and its inability to distinguish atypical mycobacteria delays accurate diagnosis. OBJECTIVE: To evaluate the polymerase chain reaction (PCR) for diagnosis of TB in bronchoalveolar lavage (BAL), blood and extra-pulmonary samples from patients with AIDS and pulmonary infiltrates. DESIGN: Specimens from 103 HIV-1-infected patients were prospectively analysed using bacteriological methods and IS6110-PCR. Smear-positive samples were also tested using 16S ribosomal-DNA-PCR to identify Mycobacterium avium complex (MAC) infections. Gold standard diagnosis relied on positive cultures or treatment outcome. RESULTS: Thirty-four patients exhibited TB, one TB and MAC and four MAC. The sensitivity of IS6110-PCR was 100% in smear-positive samples, 81.8% in smear-negative BAL, 66.7% in extra-pulmonary samples and 42.9% in blood. Its specificity was 97.1% in BAL and 100% in extra-pulmonary and blood specimens. The 16S rDNA-PCR identified M. avium from all smear-positive samples that grew MAC. CONCLUSIONS: IS6110-PCR proved useful in evaluating episodes with probable clinical diagnosis of pulmonary or mixed TB and negative smears, whereas 16S rDNA-PCR would be helpful for prompt differential diagnosis of MAC in smear-positive specimens.

AIDS-Related Opportunistic Infections↗

Survey of infections due to Staphylococcus species: frequency of occurrence and antimicrobial susceptibility of isolates collected in the United States, Canada, Latin America, Europe, and the Western Pacific region for the SENTRY Antimicrobial Surveillance Program, 1997-1999.

Between January 1997 and December 1999, bloodstream isolates from 15,439 patients infected with Staphylococcus aureus and 6350 patients infected with coagulase-negative Staphylococcus species (CoNS) were referred by SENTRY-participating hospitals in the United States, Canada, Latin America, Europe, and the Western Pacific region. S. aureus was found to be the most prevalent cause of bloodstream infection, skin and soft-tissue infection, and pneumonia in almost all geographic areas. A notable increase in methicillin (oxacillin) resistance among community-onset and hospital-acquired S. aureus strains was observed in the US centers. The prevalence of methicillin (oxacillin)-resistant S. aureus varied greatly by region, site of infection, and whether the infection was nosocomial or community onset. Rates of methicillin resistance were extremely high among S. aureus isolates from centers in Hong Kong and Japan. Uniformly high levels of methicillin resistance were observed among CoNS isolates. Given the increasing multidrug resistance among staphylococci and the possible emergence of vancomycin-resistant strains, global strategies are needed to control emergence and spread of multiply resistant staphylococci.

Anti-Bacterial Agents↗

Multicentre study of the in vitro evaluation of moxifloxacin and other quinolones against community acquired respiratory pathogens.

The in vitro activity of moxifloxacin was compared with that of ciprofloxacin, levofloxacin, ofloxacin and trovafloxacin against 710 strains (180 Streptococcus pneumoniae, 180 Haemophilus influenzae, 160 Moraxella catarrhalis and 190 Streptococcus pyogenes) isolated from patients with community-acquired respiratory tract infections. MIC values for moxifloxacin, trovafloxacin were 0.25/0.25, 0.03/0.03, 0.06/0.03 and 0.125/0.0125 mg/l for S. pneumoniae, H. influenzae, M. catharralis and S. pyogenes. Based upon the MIC(90) values and the MIC distributions, moxifloxacin and trovafloxacin were the most active of the quinolones tested. They showed enhanced activity against Gram-positive organisms including penicillin non susceptible S. pneumoniae strains. Moxifloxacin was also highly active against ciprofloxacin-resistant S. pneumoniae strains.

Anti-Infective Agents↗

Vaginal microflora associated with bacterial vaginosis in nonpregnant women: reliability of sialidase detection.

OBJECTIVE: To determine the prevalence of Gardnerella vaginalis, anaerobic bacteria and Mycoplasma hominis in vaginal specimens of women with and without bacterial vaginosis (BV) as well as to determine the sensitivity and specificity of the direct sialidase assay of vaginal fluid as a rapid test for diagnosing this syndrome. METHODS: Vaginal cultures were obtained from 109 nonpregnant women (mean age 33 +/- 7.1 years), 47 of them with clinical signs of BV (BV+) and 62 of them without BV (BV-). In addition, we determined the vaginal sialidase activity in both groups, which may serve as a feature of this syndrome. RESULTS: Anaerobic bacteria were isolated in 91% and 18% of the BV+ and BV- groups, respectively (p < 0.001). Peptostreptococcus spp., Prevotella bivia and Porphyromonas spp. were strongly associated with BV. P. bivia and Prevotella spp. represented 44% of all the anaerobes isolated in the BV+ group. All the isolated P. bivia strains presented sialidase activity. G. vaginalis and M. hominis were isolated in 76% and 42% of the BV+ and 1% and 0% of the BV- women, respectively (p < 0.001). Mobiluncus morphotypes were observed in 34% of the BV+ and 0% of BV- women. Sensitivity, specificity, positive predictive value and negative predictive value of sialidase activity were 81%, 94%, 90% and 86%, respectively. CONCLUSIONS: Our data demonstrate a strong association between G. vaginalis, M. hominis, and P. bivia and BV. Sialidase activity and Gram stain of vaginal fluid represent accurate methods for diagnosing BV.

Adult↗

Rationale for treating community-acquired lower respiratory tract infections with amoxicillin/sulbactam combination through pharmacodynamic analysis in the setting of aminopenicillin-resistant organisms.

In order to establish a rationale for treating community-acquired lower respiratory tract infections, we assess here the pharmacodynamics of amoxicillin/sulbactam, 500mg/500mg, a formulation marketed in Argentina since 1988 and currently available in 17 countries, against the major pathogens, in comparison with that of a novel formulation (875mg/125mg, see J Chemother 2000; 12: 223-227). In time-kill studies, both bactericidal and inhibitory activity were seen in the 1.5- and 6-h sera, obtained from 12 volunteers after a single oral dose, against both a penicillin-susceptible and an -intermediate Streptococcus pneumoniae strain, as well as against Moraxella catarrhalis and a beta-lactamase-negative Haemophilus influenzae strain. Only the 1.5-h sera proved bactericidal against a penicillin-resistant S. pneumoniae strain (MIC, 2 microg/ml) and a beta-lactamse-positive H. influenzae isolate. This study suggests that amoxicillin/sulbactam (500mg/500mg) is still a suitable option for treating community-acquired lower respiratory tract infections, allowing a b.i.d. dosing schedule. Caution should be taken with pneumonia caused by beta-lactamase-positive H. influenzae or penicillin-resistant (MIC > or =2 microg/ml) S. pneumoniae isolates. Either shorter dosing intervals (t.i.d.) or a higher amoxicillin content in the formulation (i.e. 875 mg) may be required in these situations.

Administration, Oral↗

Activity of gatifloxacin compared to those of seven agents against bacteria recovered from outpatients with respiratory tract infection.

The in vitro activity of gatifloxacin and levofloxacin, ciprofloxacin, penicillin, ampicillin, ampicillin-sulbactam, ceftriaxone and clarithromycin was evaluated against 173 S. pneumoniae strains (128, penicillin-susceptible strains; 32, intermediate penicillin- resistant strains and 13, penicillin-resistant strains), 163 H. influenzae strains (128, beta-lactamase non-producer; 35, beta-lactamase producers), 111 M. catarrhalis (9, beta-lactamase non-producer; 102, beta-lactamase producers), 95 Streptococcus pyogenes and 116 S. aureus strains (96, methicillin-susceptible; 20, methicillin-resistant) recovered from outpatients with respiratory tract infection. Based upon the MICs at which 50% and 90% of the isolates were inhibited we concluded that gatifloxacin proved to be the most active antibiotic against respiratory pathogens, including all the penicillin-resistant pneumococci and H. influenzae or M. catarrhalis producing beta-lactamase. Furthermore, their MICs against S. pneumoniae and methicillin-resistant S. aureus were lower than those of levofloxacin and ciprofloxacin.Therefore, this new fluoroquinolone displayed in vitro features that make it suitable for treating community-acquired respiratory tract infections.

Anti-Bacterial Agents↗

Comparison of several methods to determine methicillin-resistance in Staphylococcus aureus with focus on borderline strains.

We compared the performance of several phenotypic tests to detect methicillin-resistant Staphylococcus aureus, with special focus on borderline strains. The reliability of the agar screen oxacillin and BBL Crystal tests was asserted for all methicillin-susceptible (n = 25), -resistant (n = 29) and borderline beta-lactamase-hyperproducer (n = 10) strains. Whereas these tests failed to detect 4 of 5 rare borderline strains containing few cells with high-level methicillin resistance (i.e., a frequency of 10(-7)-10(-8)), a "two-temperature" disk diffusion method, performed simultaneously at 35 and 42 degrees C, detected all of such strains.

Ampicillin↗

Comparative in vitro bactericidal activity between cefepime and ceftazidime, alone and associated with amikacin, against carbapenem-resistant Pseudomonas aeruginosa strains.

Fifteen unique isolates of carbapenem-resistant Pseudomonas aeruginosa were selected for time-kill studies to assess the bactericidal activity of cefepime (CFP) and ceftazidime (CZD) (at 4 and 16 microg/mL), alone and associated with amikacin (AMK) (4 microg/mL). CFP proved more active than CZD (p < 0.05, Student's t test). Bactericidal activity after 24-h incubation was only achieved by the combination of CFP (16 microg/mL) plus AMK. The higher in vitro activity of cefepime over that of ceftazidime against imipenem-resistant P. aeruginosa strains highlights the differences of these drugs beyond Enterobacterspp. and Staphylococcus aureus.

Amikacin↗

A pharmacodynamic model to support a 12-hour dosing interval for amoxicillin/sulbactam, a novel oral combination, in the treatment of community-acquired lower respiratory tract infections.

We evaluated, by time-kill studies, the pharmacodynamics of amoxicillin/sulbactam (AMX/SUL, 875 mg/125 mg), a novel oral combination, against the major respiratory pathogens in 12 volunteers receiving a single dose. The sera corresponding to 50% of a 12-h dosing interval displayed either bactericidal or inhibitory activity against both a penicillin-susceptible and a penicillin-intermediate Streptococcus pneumoniae strain (penicillin MIC of 0.03 and 0.25 microg/ml, respectively), as well as against a beta-lactamase-positive Moraxella catarrhalis and a beta-lactamase-negative Haemophilus influenzae strain. Both the peak samples and those corresponding to 4 h after dose (i.e. 33% of a 12-h dosing interval) proved active against both a penicillin-resistant S. pneumoniae (MIC, 2 microg/ml) and a beta-lactamase-positive H. influenzae strain. The AMX-SUL formulation evaluated in this study showed pharmacodynamic features that support clinical trials to assess its efficacy in the treatment of lower respiratory tract infections with a 12-h dosing interval regimen.

Administration, Oral↗

Efficacy and pharmacodynamics of teicoplanin given daily during the first 3 days and then on alternate days for methicillin-resistant Staphylococcus aureus infections.

Fifteen evaluable patients (mean age, 67 years) were enrolled to assess the efficacy of teicoplanin, 6 mg/kg given daily during the first 3 days and then on alternate days, for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections. Eight patients had soft tissue infections, four catheter-associated bacteraemia, two osteomyelitis and one pneumonia. Clinical cure was observed in 13 of 15 patients. Both clinical and bacteriological failures were shown in the two patients with osteomyelitis. The mean serum levels of teicoplanin (mg/L) were 22, 8 and 6.7 for peak, 24 h and 48 h troughs, respectively. The dosage employed in this study proved effective in non-deep-seated MRSA infections.

Adult↗

Species belonging to the "Streptococcus milleri" group: antimicrobial susceptibility and comparative prevalence in significant clinical specimens.

The association between the three species belonging to the "Streptococcus milleri" group and different sites of isolation was examined for 73 successive strains recovered from clinically significant, purulent infections. Susceptibility testing was performed on 64 of these strains. The present study supports the association of particular species with different clinical sources. Susceptibility data suggest that emerging penicillin resistance among Streptococcus anginosus and Streptococcus intermedius isolates may represent a potential clinical problem in the therapeutic management of infections caused by these species.

Anti-Bacterial Agents↗

Synergy characterization for Enterococcus faecalis strains displaying moderately high-level gentamicin and streptomycin resistance.

Synergy of 14 Enterococcus faecalis strains displaying moderately high-level aminoglycoside resistance (MICs, 500 and 256 to 1,000 micrograms/ml for gentamicin and streptomycin, respectively) was characterized by time-kill studies. All strains proved resistant to penicillin plus the respective aminoglycoside. Strains with moderately high-level aminoglycoside resistance should be considered to exhibit high-level resistance in severe infections.

Drug Resistance, Microbial↗

Abscess caused by vancomycin-resistant Lactobacillus confusus.

Several isolates of vancomycin-resistant Lactobacillus confusus from human sources have been described, but to our knowledge, no well-documented infection attributable to this organism has been published. A thumb abscess caused by this bacterium in a healthy 49-year-old male is reported here. He was successfully treated by surgical drainage and cephalothin.

Abscess↗

[Endocarditis due to Corynebacterium xerosis].

Corynebacterium sp. are found as normal flora in skin and mucosal sites. They have been isolated in empyemas, brain abscesses, blood cultures and ventricular shunts. About 9-10% of early-onset and 4-5% late-onset prosthetic valve endocarditis are due to different species of the so-called "diphteroids". A 30 year-old white female was admitted after 30 days with fever of undetermined origin. A mitral prosthesis had been fitted in 1977. On physical examination a protomesosystolic mitral murmur, petechiae, retinal hemorrhages and hepatosplenomegaly were detected. Laboratory tests showed 37% hematocrit, 14,800/mm3 white blood cells, 78 mm ESR, urinary sediment: less than 30/h.p.f. red blood cells. A new first-degree A-V block was detected. Blood cultures were negative. Due to persistent fever, progressive anemia, leukocytosis and new vegetations on echocardiogram, surgery was performed. A mitral valve ring abscess was found. Corynebacterium xerosis was isolated from surgical specimens. The strain was found susceptible to penicillin, ampicillin, oxacillin, ticarcillin, piperacillin, cephalotin, cefoxitin, cefoperazone, rifampin, gentamicin, amikacin, and norfloxacin. Studies with clindamycin, disclosed MIC and MBC = 0.25 mg/l. The patient received 1800 mg/day clindamycin for 4 weeks. Serum cidal studies showed a peak concentration 1/128 and a titre of trough 1/4. Negative control blood cultures were obtained. She has remained well for nine months after treatment. Corynebacterium sp. can cause "apparently" negative blood cultures. Blood samples should be incubated for more than 15 days before they can be considered negative. Almost 50% of previously described cases have been detected during the six months after cardiac surgery. Mortality has been high (48%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗