Biomedical subjects
Publications and source records attributed to M L Corrado.
The first evidence of the potential pathogenicity of Mycobacterium thermoresistibile is presented. This mycobacterium, initially identified as Mycobacterium gordonae, was isolated repeatedly from sputum, a bronchoscopy specimen. and later, an open lung biopsy. The distinctive characteristics are described, including the unique ability of the organism to grow at 52 degrees C.
Three patients with Staphylococcus epidermis meningitis associated with cerebrospinal fluid (CSF) shunt devices were treated with a combination of intravenous vancomycin and oral rifampin. Two of the isolates were methicillin-resistant. All patients had a favorable clinical response. Time-kill curves showed that the addition of rifampin to vancomycin resulted in enhanced bactericidal activity against all isolates when compared to either antibiotic alone. This finding suggests that the combination of oral rifampin and intravenous vancomycin may be useful in the treatment of methicillin-resistant and recalcitrant methicillin-sensitive S. epidermis meningitis associated with CSF shunts. In vitro susceptibility testing should be performed.
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Group B streptococci (GBS) have been infrequently recognized as a cause of pharyngitis. We report three cases of GBS pharyngitis in patients with underlying diseases, two of whom were treated with and responded incompletely to oral beta-lactam antibiotics. The susceptibility of 20 clinical isolates of GBS was tested by a broth dilution method to six antibiotics which could conceivably be used in the therapy of GBS pharyngitis. Penicillin G, clindamycin, and erythromycin were most active with mean minimal inhibitory concentrations (MIC) of 0.06 μg/ml or less. Rifampin and cefaclor were least active with mean MICs of 0.71 ug/ml or more. Ampicillin was intermediate in its activity. Therapy traditionally used for Group A streptococcal (GAS) pharyngitis may, at times, be suboptimal for GBS pharyngitis in compromised patients. This may be due to higher minimal bactericidal concentrations (MBC) of GBS than GAS, to inadequate penetration of penicillins into pharyngeal tissues or to host factors. It is suggested that GBS can cause pharyngitis in adults, particularly the compromised patient, and that in cases where there is a poor response to penicillin or ampicillin therapy, alternative drugs (erythromycin or clindamycin) may be used.
Three cases of pyogenic liver abscess following blunt trauma to the torso are described. The association between blunt trauma with liver contusion and the development of bacterial pyogenic liver abscess is explored. Reported series of liver abscess are reviewed. It is suggested that physicians look for the development of liver abscess in patients who have had major blunt trauma to the torso. Physicians should also inquire about blunt trauma in patients with documented pyogenic liver abscesses.
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LY 127935, a new oxa beta-lactam with an expanded gram-negative spectrum, was administered intravenously to seven patients, including two patients with documented gram-negative bacillary meningitis. In the patients receiving continuous therapy (2 g intravenously every 8 hours) cerebrospinal fluid trough levels of LY were never less than 6 micrograms/ml. Peak cerebrospinal fluid levels of LY ranged from 25 to 39 micrograms/ml and occurred approximately 2.5 hours after the intravenous administration of the drug. Cerebrospinal fluid levels of LY were 19 per cent to greater than 100 per cent of simultaneous serum levels. Cerebrospinal fluid bactericidal activity was 1:4 to 1:256. Intravenous LY, because of its expanded gram-negative spectrum and excellent cerebrospinal fluid penetration, is a potentially useful antibiotic in the treatment of gram-negative bacillary meningitis.
Quantitative cultures were done on 149 intravenous catheters and 40 additional intravascular inserts. Intradermal and intravascular segments of the insert were cultured separately. The inserts were immersed in broth and flushed. The number of colony-forming units (cfu) per insert was estimated by surface culture of serial dilution of the broth. Nonquantitative culture of undiluted broth was also done. Since all inserts associated with bacteremia had at least 10(3) cfu, inserts greater than 10(3) cfu were considered infected. Staphylococcus epidermidis was more likely than more virulent organisms to colonize an insert without causing bacteremia. The inserts in one bacteremic patient were infected from a distant bloodstream focus; however, in the majority of patients, quantitative intradermal cultures suggested that the insertion site was the portal of entry. In bacteremic patients, either a positive quantitative or a nonquantitative culture identified an infected insert. However, only 33% of positive nonquantitative insert cultures from nonbacteremic patients were confirmed by quantitative insert culture.
Forty clinical isolates of Pseudomonas aeruginosa were tested for their susceptibility to cefoperazone, cefotaxime, moxalactam, piperacillin, N-formimidoyl thienamycin (MK0787), and gentamicin at three different inocula. At an inoculum of 5 x 10(3) colony-forming units (CFU) per ml, the minimum inhibitory concentrations (in micrograms per milliliter) for 90% of isolates (MIC90) were as follows: gentamicin, 1; N-formimidoyl thienamycin, 2; cefoperazone, 4; piperacillin, 8; moxalactam, 16; and cefotaxime, 16. When the inoculum was increased to 5 x 10(5) CFU/ml, the MIC90 for all drugs tested increased. Among the beta-lactam antibiotics, N-formimidoyl thienamycin and cefoperazone had the lowest MIC90 (8 micrograms/ml) at this inoculum. When the inoculum was increased further to 5 x 10(7) CFU/ml, an MIC90 could be determined only for gentamicin and N-formimidoyl thienamycin (4 and 8 micrograms/ml, respectively). Indeed, the MIC50 for moxalactam, cefotaxime, cefoperazone, and piperacillin was 128 micrograms/ml or more at this inoculum. The minimum bactericidal concentration for 90% of isolates (MBC90) at an inoculum of 5 x 10(5) CFU/ml ranged from 8 micrograms/ml for gentamicin and N-formimidoyl thienamycin to 128 micrograms/ml for cefotaxime. At the highest inoculum, however, whereas the MBC90 for gentamicin and N-formimidoyl thienamycin remained at 8 micrograms/ml, the MBC90 for each of the other drugs was greater than 128 micrograms/ml. N-Formimidoyl thienamycin was the only drug tested for which an MIC100 and MBC100 (MIC and MBC for 100% of isolates) could be determined, and these were not significantly different from the MIC90 and MCB90.
We report three cases of serious non-group b Haemophilus influenzae infections. The significance of these isolates with respect to both biotypes and serotypes is discussed.
Two patients are described with subcutaneous infections due to Phialophora richardsiae. Both were diabetics and originally came from subtropical areas. One of the patients had a cystic lesion which was well encapsulated while the other had a large ulcerating lesion with draining sinus tracts. The organisms were found to be susceptible to cycloheximide but resistant to 5-fluorocytosine, miconazole and amphotericin B. There was some variability in the degree of resistance depending upon whether the primary or secondary phialoconidia were tested. While simple excision appears curative for the solitary cystic type of lesion, therapy of the ulcerating form of the disease remains problematic.
A case of nasopalatine mucormycosis in a patient with chronic renal failure is reported. Early recognition is contingent on histopathological examination of tissue and culturing. Vigorous treatment with amphotericin B and surgical intervention averted possible orbital-cranial involvement and effected a cure. When a chronically debilitated patient has signs of intraoral necrosis or facial swelling and necrosis, or both, the clinician should be alert to the possibility of a mucormycotic infection.
The antimicrobial susceptibilities were determined for 14 strains of Yersinia enterocolitica, 28 strains of Eikenella corrodens, 10 strains of penicillin-resistant Streptococcus pneumoniae, and 10 strains of penicillin-susceptible S. pneumoniae. Y. enterocolitica was found to be susceptible to the aminoglycosides tested and to chloramphenicol, moxalactam, cefoperazone, and cefotaxime but resistant to ampicillin and variably susceptible to carbenicillin, cefoxitin, and cefazolin. On a weight basis, cefotaxime and moxalactam were the most active agents against E. corrodens. Most strains of E. corrodens were resistant to the aminoglycosides tested: gentamicin, tobramycin, kanamycin, and amikacin. Penicillin-resistant S. pneumoniae was most susceptible to cefotaxime and moxalactam. Cefotaxime was consistently active against all tested strains of Y. enterocolitica, E. corrodens, and penicillin-resistant S. pneumoniae, three unusual but clinically significant pathogens.
Results of the treatment of gram-negative bacillary meningitis have been disappointing: mortality is extremely high, and treatment with chloramphenicol has shown a high failure rate. This failure rate for chloramphenicol is consistent with the wide gap between minimal inhibitory concentration and minimal bactericidal concentration of this drug for Escherichia coli, Klebsiella, and other Enterobacteriaceae. Cefotaxime, a new cephalosporin, is cidal for most gram-negative bacteria at concentrations of less than 0.25 microgram/ml. By late 1981, 137 patients with meningitis due to a variety of bacteria had been treated with this agent. Bacteriologic cure rates were 93% for meningitis due to Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae and 88% for meningitis due to gram-negative bacteria (94.4% for meningitis due to E. coli and Klebsiella). This new antibiotic shows considerable promise in the treatment of these forms of meningitis.