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Biomedical subjects

C J Fernandes

Publications and source records attributed to C J Fernandes.

At least 19 recordsLinked to original sources
PubMed2001

Red blood cell transfusion does not increase oxygen consumption in critically ill septic patients.

BACKGROUND: Red blood cell (RBC) transfusion is commonly used to increase oxygen transport in patients with sepsis. However it does not consistently increase oxygen uptake at either the whole-body level, as calculated by the Fick method, or within individual organs, as assessed by gastric intra-mucosal pH. AIM: This study evaluates the hemodynamic and oxygen utilization effects of hemoglobin infusion on critically ill septic patients. METHODS: Fifteen septic patients undergoing mechanical ventilation whose hemoglobin was <10 g% were eligible. Ten patients (APACHE II: 25.5 +/- 7.6) received an infusion of 1 unit of packed RBC over 1 h while sedated and paralyzed. The remaining five control patients (APACHE II: 24.3 +/- 6.0) received a 5% albumin solution (500 ml) over 1 h. Hemodynamic data, gastric tonometry and calorimetry were obtained prior to and immediately after RBC transfusion or 5% albumin infusion. RESULTS: Transfusion of RBC was associated with an improvement in left ventricular systolic work index (38.6 +/- 12.6 to 41.1 +/- 13.0 g/min/m2; P = 0.04). In the control group there was no significant change in the left ventricular systolic work index (37.2 +/- 14.3 to 42.2 +/- 18.9 g/min/m2). An increase in pulmonary vascular resistance index (203 +/- 58 to 238 +/- 49 dyne/cm5/m2; P = 0.04) was also observed, while no change was produced by colloid infusion (237 +/- 87.8 to 226.4 +/- 57.8 dyne/cm5/m2). Oxygen utilization did not increase either by Fick equation or by indirect calorimetry in either group. Gastric intramucosal pH increased only in the control group but did not reach statistical significance. CONCLUSION: Hemoglobin increase does not improve either global or regional oxygen utilization in anemic septic patients. Furthermore, RBC transfusion may hamper right ventricular ejection by increasing the pulmonary vascular resistance index.

APACHE↗
PubMed2001

Evaluation of the MRSA-Screen Test in detecting oxacillin resistance in community and hospital isolates of Staphylococcus aureus.

The MRSA-Screen Test (Denka Seiken Co., Japan), a latex agglutination test to detect penicillin-binding protein 2a, was compared with PCR for the detection of oxacillin resistance in Staphylococcus aureus. A total of 77 oxacillin-sensitive and 269 oxacillin-resistant (ORSA) isolates were evaluated. Of the ORSA isolates, 186 were non-multiresistant (NORSA), defined as being resistant to two or fewer antibiotics other than beta-lactams. Eighty-three were multiresistant ORSA (MORSA) strains. If PCR is considered the gold standard test, then the sensitivity, specificity, positive and negative predictive values of the MRSA-Screen Test were 100, 99, 99 and 100%, respectively. The endpoint was hard to read with NORSA strains that took longer than 60 s to react. MORSA strains took a median 12 s (range 5-60 s) to give a positive reaction with the MRSA-Screen Test, whereas NORSA strains took a median 30 s (range 5-180 s), a difference which was significantly different (P < 0.0001, two-tailed Mann-Whitney unpaired two sample test). NORSA strains had an MIC50 of 128 mg/l and MIC90 of 256mg/l, whereas MORSA strains had an MIC50 and MIC90 of >256mg/l. The time that the MRSA-Screen Test took to agglutinate with ORSA strains correlated weakly with the MIC (r2 = 0.26). Detection of methicillin resistance cost AUD$9 per isolate with the MRSA-Screen Test, compared with AUD$13 per isolate with mecA PCR. The MRSA-Screen Test gave excellent sensitivity and specificity, and was quicker and cheaper than PCR. The full 3 min should be allowed to elapse before calling a test negative. Organisms giving indeterminate reactions should be tested for the mecA gene by PCR.

Antibodies, Monoclonal↗
PubMed2001

In vitro activities of ertapenem (MK-0826) against recent clinical bacteria collected in Europe and Australia.

Ertapenem (MK-0826, L-749,345) is a 1-beta-methyl carbapenem with a long serum half-life. Its in vitro activity was determined by broth microdilution against 3,478 bacteria from 12 centers in Europe and Australia, with imipenem, cefepime, ceftriaxone, and piperacillin-tazobactam used as comparators. Ertapenem was the most active agent tested against members of the family Enterobacteriaceae, with MICs at which 90% of isolates are inhibited (MIC(90)s) of < or =1 microg/ml for all species. Ertapenem also was more active than imipenem against fastidious gram-negative bacteria and Moraxella spp.; on the other hand, ertapenem was slightly less active than imipenem against streptococci, methicillin-susceptible staphylococci, and anaerobes, but its MIC(90)s for these groups remained < or =0.5 microg/ml. Acinetobacter spp. and Pseudomonas aeruginosa were also much less susceptible to ertapenem than imipenem, and most Enterococcus faecalis strains were resistant. Ertapenem resistance, based on a provisional NCCLS MIC breakpoint of > or =16 microg/ml, was seen in only 3 of 1,611 strains of the family Enterobacteriaceae tested, all of them Enterobacter aerogenes. Resistance was also seen in 2 of 135 anaerobes, comprising 1 Bacteroides fragilis strain and 1 Clostridium difficile strain. Ertapenem breakpoints for streptococci have not been established, but an unofficial susceptibility breakpoint of < or =2 microg/ml was adopted for clinical trials to generate corresponding clinical response data for isolates for which MICs were as high as 2 microg/ml. Of 234 Streptococcus pneumoniae strains tested, 2 required ertapenem MICs of 2 microg/ml and one required an MIC of 4 microg/ml, among 67 non-Streptococcus pyogenes, non-Streptococcus pneumoniae streptococci, single isolates required ertapenem MICs of 2 and 16 microg/ml. These streptococci also had diminished susceptibilities to other beta-lactams, including imipenem as well as ertapenem. The Etest and disk diffusion gave susceptibility test results in good agreement with those of the broth microdilution method for ertapenem.

Anti-Bacterial Agents↗
PubMed1999

Cardiac troponin: a new serum marker of myocardial injury in sepsis.

OBJECTIVE: Echocardiogram-derived left ventricular ejection fraction (LVEF) is usually utilized to evaluate left ventricular function, including that of septic patients. However, LVEF is greatly influenced by afterload. The aim of this study was to test the hypothesis that troponin I, a serum marker of myocardial injury, may be able to detect left ventricular involvement by the septic process, being at least as sensitive an indicator of left ventricular dysfunction as LVEF in these patients. DESIGN: Comparison of echocardiogram-derived LVEF with serum levels of troponin I in ten critically ill septic patients. SETTING: General intensive care unit in a tertiary care private hospital. PATIENTS: Ten critically ill septic patients with no previous documented heart disease. MEASUREMENTS AND RESULTS: Patients were simultaneously submitted to a two-dimensional echocardiogram and troponin I determinations. LVEFs and troponin I levels were analyzed in a two-by-two table in order to validate troponin I as a new biochemical marker of myocardial injury in sepsis. All the patients whose LVEF was < 0.5 had elevated troponin I levels (kappa = 0.61, p = 0.035). CONCLUSIONS: Identification of myocardial dysfunction in septic patients has been a challenging task. Troponin I, a serum marker of myocardial injury, may be of great help in the recognition of myocardial involvement by sepsis in a noninvasive and readily available way.

Adult↗
PubMed1997

A national collaborative study of the in vitro activity of oral cephalosporins and loracarbef (LY 163892). Australian Group for the Study of Antimicrobial Resistance (AGAR).

A national collaborative study involving the laboratories of 17 Australian hospitals examined the in vitro activity of loracarbef, cefaclor, cephalexin, amoxycillin and amoxycillin/clavulanate against 2661 recently isolated common bacterial pathogens. Loracarbef was the most active agent against Escherichia coli (MIC90 = 1 mg/l) and had activity comparable to other agents against Klebsiella pneumoniae and Proteus mirabilis. Like the oral cephalosporins, it had no activity against species of Enterobacter and Serratia. beta-lactamase-producing Staphylococcus aureus and Haemophilus influenzae were moderately sensitive to loracarbef (MIC90 = 8 mg/l for both species). Streptococcus pneumoniae was moderately sensitive to loracarbef (MIC90 = 2 mg/l) but strains which were insensitive to penicillin were often highly resistant.

Administration, Oral↗
PubMed1995

Multi-centre collaborative study for the in vitro evaluation of new macrolides dirithromycin and erythromycylamine. Australian Group for Antimicrobial Resistance (AGAR).

A national study was conducted to determine the in vitro activity of 2 newer macrolides, dirithromycin and erythromycylamine compared with that of erythromycin, tetracycline and penicillin. Nineteen major teaching hospitals participated in the study. Minimal Inhibitory Concentrations (MICs) were determined by agar dilution, mostly using Iso-Sensitest Agar and an inoculum of 10(4) cells per spot. 2284 clinically significant strains were isolated in late 1991 and early 1992, comprising 1736 Gram-positive cocci, 355 Haemophilus influenzae, 97 Moraxella catarrhalis, 32 Listeria monocytogenes, 25 Neisseria meningitidis and 39 Neisseria gonorrhoeae were tested. The study indicates that dirithromycin and erythromycylamine possess antibacterial activity equivalent to that of erythromycin against most Gram-positive cocci and M. catarrhalis. Strains resistant to erythromycin were also resistant to dirithromycin and to erythromycylamine. Tetracycline was as active as the macrolides against both penicillin-resistant and penicillin-susceptible strains of Staphylococcus aureus. Coagulase-negative penicillin-resistant staphylococci, compared with tetracycline, were relatively resistant to the macrolides. H. influenzae was less susceptible than the Gram-positive cocci.

Anti-Bacterial Agents↗
PubMed1994

Erythropoietin in very preterm infants.

Three neonates (a male and two females of gestational ages 27, 27 and 29 weeks with birthweight 985, 660 and 1130 g), born to parents who are Jehovah's Witnesses, were admitted to our neonatal intensive care unit over a 2 month period in 1992. Human recombinant erythropoietin (rHuEpo, 200 u/kg sc. on alternate days for 6-8 weeks) was started early in conjunction with strict control of blood sampling in an attempt to avoid the need for blood transfusion. The lowest haemoglobin recorded was 95 g/L at 35 days of age in the first infant. The amount of blood withdrawn for sampling was 21.4 mL, 20.7 mL and 5.5 mL, respectively. All were discharged near their expected birthdate, never having received a blood transfusion in the Nursery. It is possible to manage sick, very preterm, very low birthweight neonates in a neonatal intensive care setting without the use of blood transfusions by the early use of rHuEpo in conjunction with strict control of blood sampling.

Anemia, Neonatal↗
PubMed1991

Clinical profile of severe birth asphyxia.

In this retrospective analysis, 56 babies with Apgar score 3 and less were studied. In 33, successful bag-mask ventilation was carried out. Seventeen babies received endotracheal IPPV. In 9 out of them bag-mask ventilation was never tried whereas in 8 bag-mask ventilation had failed. In 6 babies physical stimulation and blast of oxygen on the face was adequate. Following this experience, in the subsequent years, endotracheal intubation was required mainly in extremely low birth weight babies or babies with Apgar score 0 at birth. During the study period, drugs were used in about 50% babies. In subsequent years this figure has come down to 10%, that too in special situations. This study helped us to evolve a policy in resuscitations severely asphyxiated babies. Bag-mask ventilation is the first choice. Failure to achieve progressively improving Apgar score by 1 minute, usually 4-5, is an indication for endotracheal intubation. Drugs are required in special situations only.

Apgar Score↗
PubMed1988

In vitro activity of A-56619 and A-56620 against multi-resistant and routine clinical isolates.

A-56619 and A-56620 are two new quinolone compounds that are currently being studied. They were found to be active against multi-resistant and routine isolates of Staphylococcus aureus, enterobacteria, aminoglycoside-sensitive and resistant strains of Pseudomonas aeruginosa. Most of the enterobacteria were inhibited by 0.5-1 mg/l of A-56620. A-56619 was less active, concentrations of 1-4 mg/l being needed for 90% inhibition. Both the compounds were active at concentrations of 0.5-1 mg/l against staphylococci, including multi-resistant S. aureus. The MIC90 for P. aeruginosa was 1-2 mg/l for A-56620 and 8 mg/l for A-56619.

Anti-Bacterial Agents↗
PubMed1986

In vitro antibacterial activity of enoxacin (CI-919).

Antibacterial activity of enoxacin was evaluated against more than 3,700 clinical isolates using the agar-dilution method and an inoculum of 10(4)-10(5) cells per site. For comparison other antibiotics appropriate for each species were also included. For most enterobacteria and for Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa, the MIC90 of enoxacin was below 2 mg/l. Serratia marcescens was more resistant; the MIC90 being 4 mg/ml. Enoxacin also showed high activity against Campylobacter jejuni and Neisseria gonorrhoeae. Streptococci were comparatively resistant, 32 mg/l to 64 mg/l of the compound being required to inhibit 90% of strains.

Anti-Bacterial Agents↗
PubMed1985

A replicator method for the combined determination of minimum inhibitory concentration and minimum bactericidal concentration.

Minimal bactericidal concentrations (MBCs) of nine antimicrobial agents were determined for clinical isolates by a replica plating method. Membranes were placed on the antibiotic-containing plates and the organisms replicated onto the membranes. After 18 h incubation the minimal inhibitory concentrations (MICs) were determined, the membranes were transferred to antibiotic-free plates and incubated a further 18 h and the MBCs determined. MICs and MBCs were also determined in broth. The reproducibility of the 'membrane' method and the agreement of these results for MIC and MBC with the agar and/or broth methods was satisfactory for most antibiotics, within one two-fold dilution. With sulphamethoxazole, trimethoprim and co-trimoxazole the results were less satisfactory, especially with Gram-negative rods, but agreement within two dilutions could be achieved.

Anti-Bacterial Agents↗
PubMed1985

Comparative antibacterial activities of new beta-lactam antibiotics against Pseudomonas aeruginosa.

In vitro activity of nine new cephalosporins and penicillins was determined against 417 isolates of Pseudomonas aeruginosa. Carbenicillin, ticarcillin, gentamicin, tobramycin and netilmicin were also included in the study. Imipenem showed highest activity. More than 90% of the isolates were susceptible to ticarcillin, piperacillin, azlocillin, cefoperazone, cefsulodin and to tobramycin. 57 isolates included in the study were resistant to gentamicin (MIC greater than 4 mg/l); of these, none were resistant to imipenem, and more than 80% were susceptible to piperacillin, azlocillin, cefoperazone and cefsulodin.

Anti-Bacterial Agents↗
PubMed1983

An evaluation of recently developed antibiotics.

A number of newer antibiotics, broad-spectrum penicillins and cephalosporins, have been evaluated against Gram-negative rods. The organisms were selected for multi-resistance and transferable resistance factors. None of the broad-spectrum penicillins was much use against most of the organisms. Ceftriaxone, cefotaxime, latamoxef (moxalactam) and N-formimidoyl thienamycin were all highly effective against most multi-resistant Gram-negative bacilli; cefoperazone being inferior to them. Enterobacter and Serratia strains were relatively resistant to all the agents mentioned and against Acinetobacter only N-formimidoyl thienamycin showed much activity. Thus, use of these drugs may increase the proportion of infections due to organisms such as Serratia or Acinetobacter.

Acinetobacter↗