D. Merzbach

Nosocomial pseudomonas cepacia infection associated with chlorhexidine contamination

During the period of January to July 1980, a marked increase in the number of Pseudomonas cepacia isolates was observed in a microbiologic surveillance program. Although P. cepacia was isolated from wound specimens and vaginal cultures, the majority of isolates were of urinary origin from catheterized patients. Retrospective chart analysis of the patients failed to verify a causal pathogenic role for P. cepacia. However, fulminant sepsis subsequently developed in two hospitalized immunocompromised patients, with both blood and urine cultures positive for P. cepacia. Investigation revealed the presence of this organism in chlorhexidine (0.2 percent) mouthwash as well as other chlorhexidine antiseptic solutions used for routine urologic and obstetric procedures. The source of the P. cepacia was identified as the rubber tubing in the pharmacy through which deionized water passed during the dilution of concentrated (5 percent) chlorhexidine gluconate. In vitro tests demonstrated that P. cepacia was resistant to 0.2 percent chlorhexidine.

Phagocytosis-induced mutagenesis in bacteria.

Dark mutants of the luminous bacteria Photobacterium fischeri reverted to hereditary stable luminescent forms when incubated with human polymorphonuclear neutrophils (PMN). The maximal mutagenic effect occurred during the first 15 min of phagocytosis, and was dependent on the phagocyte:bacterium ratio as well as on the integrity of the PMN cells. Heat-killed phagocytes or disintegrated phagocytes did not show any mutagenic activity, whereas the supernatant of the phagocytosis reaction exerted mutagenic activity. Scavengers of hydroxyl radical such as mannitol or benzoate and scavengers of singlet oxygen such as beta-carotene, as well as the presence of superoxide dismutase, prevented the mutations. The role of reactive oxygen metabolites in the phagocyte-mediated mutagenic process is discussed.

Susceptibility of different yeast species to environmental toxic metals.

The purpose of the study reported here was to investigate the relative resistance of yeast species to various metallic and metalloid ions, with a view to gaining more knowledge on this subject, as resistant species may become dominant in habitats contaminated with the relevant metals. Saccharomyces cerevisiae, Candida albicans and Candida tropicalis were grown in media containing different concentrations of mercury (as HgCl(2)), cadmium (as CdCl(2)), lead (as Pb(CH(3)COO)(2)), arsenic (as Na(2)HAsO(4)) and selenium (as Na(2)SeO(3)) for various intervals. Invariably, the two Candida species turned out to be more resistant to all the metals studied than S. cerevisiae. The metal showing the highest toxicity for these species was mercury, with cadmium being the second, lead, the third and arsenic and selenium being the least toxic elements. Strains showing resistance to mercury were isolated, even in the case of S. cerevisiae.

Phagocytosis of mucoid and nonmucoid strains of Pseudomonas aeruginosa

In order to evaluate the role of mucoid coating of clinical isolates of Pseudomonas aeruginosa as a virulence factor, opsonophagocytosis of mucoid and nonmucoid strains of P. aeruginosa were studied by three different methods: uptake of [3H]adenine-labeled bacteria, oxygen consumption, and chemiluminescence production by phagocytosing polymorphonuclear leukocytes. All three methods showed a strong correlation with regard to phagocytosis of the bacterial isolates. As a group, the mucoid strains of P. aeruginosa demonstrated significantly reduced phagocytic uptake by leukocytes when compared to nonmucoid strains, although occasionally mucoid strains did exhibit normal uptake. In vitro growth of mucoid strains under nonstationary conditions was associated with reduced mucoid coating and with a corresponding increase in susceptibility to leukocyte phagocytosis. Although the overall bactericidal activity of human polymorphonuclear leukocytes for mucoid strains was diminished, this appears to be a function of reduced ingestion since the rate of intracellular killing was similar for mucoid and nonmucoid strains. The enhanced susceptibility of mucoid strains to spontaneous bactericidal activity of pooled human serum was confirmed. Mucoid-producing strains produced less protease in vitro; however, the role of this phenomenon in influencing phagocytosis is unknown.

Single-dose antimicrobial therapy in the treatment of asymptomatic bacteriuria in pregnancy

Fifty obstetric patients with asymptomatic bacteriuria were treated by single-dose antimicrobial therapy. The immediate cure rate was 84% and the recurrence rate was 12%. Seven of the eight patients in whom single-dose treatment failed responded to subsequent 7-day therapy with the same drug, indicating renal involvement. A 50% recurrence rate in the group of patients in whom single-dose treatment failed was compared with a 5% recurrence rate in the group cured by single-dose therapy, which indicates that failure with single-dose antimicrobial therapy can serve as a therapeutic test to identify patients at high risk for recurrent bacteriuria and its sequelae during pregnancy. It is concluded that single-dose antimicrobial therapy is a safe and effective way to treat asymptomatic bacteriuria in pregnant patients without urologic problems in their history.

Factors affecting sperm motility. VI. sperm viability under the influence of bacterial growth in human ejaculates

The influence of bacterial growth on human sperm motility and viability was evaluated objectively with the multiple-exposure photography method. Experimental semen specimens, obtained from normal donors bh nonaseptic means of masturbation, were incubated with antibiotics at room temperature or body temperature for 24 hours. Although bacteria, grew in control specimens, were totally eradicated in all antibiotic-treated specimens, no significant difference was found between these groups with regard to sperm motility throughout the time of incubation. Sperm survival was not inhibited, nor was it extended as a result of suppression of bacterial growth. In both groups, survival time was much shorter in specimens incubated at body temperature than in those kept at room temperature. Sperm motility was not affected after 2 hours of incubation of fresh specimens with concentrations of various pathogenic bacteria similar to those found in severe prostatitis. The question of whether the use of antibiotics in the treatment of asthenospermia per se has a prognostic value is discussed.

Intraamniotic infection in the very early phase of the second trimester

A total of 157 consecutive patients were studied in an effort to examine prospectively the incidence of asymptomatic intraamniotic infection in the early phase of the second trimester. All patients were referred for amniotic fluid karyotyping. In addition, the amniotic fluids were examined for Gram stain and were directly cultured on blood agar and MacConkey agar as well as in thioglycollate broth. We found positive amniotic fluid cultures in eight cases (5.09%); however, results of Gram stain examinations were negative in all amniotic fluid samples. The data indicate that there is no correlation between white blood cells in the amniotic fluid and positive amniotic fluid culture results. Only one pregnancy with positive amniotic fluid culture resulted in a septic abortion. Therefore we can suggest that intraamniotic infection can exist early in pregnancy, even with intact membranes, and in most cases without any clinical symptoms.

Evaluation of Direct Microscopic Examination Versus Culture in the Diagnosis of Superficial Fungal Infections

Summary: Five hundred eighty six samples of skin and nail scrapings or hair clinically suspected of superficial fungal infection were studied by direct smears and cultures. 366 (62.5%) of these samples were negative by both methods. Of the remaining 220 (37.5%) samples, 114 (51.8%) were positive by the direct KOH preparation, 6 (2.7%) by culture and 100 (45.5%) by both methods. Most (72.7%) of the 214 (97.3%) KOH positive smears showed a low to high hyphal content, and 4 (1.9%) of them were culturally negative although they possessed a very high amount of hyphae. Discrepancies between the direct microscopic examination and the subsequent culture are well known in the literature and therefore this study strongly suggests the necessity of both tests for the diagnosis of superficial mycoses.

Effect of calcium ions on growth and metabolism of Saccharomyces carlsbergensis.

Addition of calcium ions increased 2- to 3-fold the growth of Saccharomyces carlsbergensis 2I in a minimal glucose-containing medium. The minimal concentration enhancing growth was 25 to 50 mug/ml CaCl2. Other divalent and trivalent cations tested, except for strontium ions, did not duplicate the calcium effect. Actively growing and dividing cells took up 45Ca2+, while resting yeast cells did not. The radiocalcium taken up was incorporated into newly synthesized structural material, presumably into the membrane protein.

Effect of an Intravenous Gammaglobulin Preparation on the Opsonophagocytic Activity of Preterm Serum against Coagulase-Negative Staphylococci

ABSTRACT. Recent reports have described cases of septicaemia caused by coagulase‐negative staphylococci in preterm neonates, mainly due to the use of artificial intravenous devices. It was of interest to examine if intravenous immunoglobulin therapy, known to be effective in group B streptococcal infections of neonates, had a similar beneficial effect in coagulase‐negative staphylococcal infections. Opsonophagocytosis of coagulase‐negative staphylococci by normal polymorphonuclear leukocytes in the presence of cord blood serum supplemented with the commercial IgG preparation ‘Sandoglobulin’ was investigated, using luminol‐dependent chemiluminescence. It was found that with two different coagulase‐negative staphylococcal strains, Sandoglobulin had a concentration‐dependent enhancing effect on the chemiluminescent response. This effect was demonstrated in the presence of native as well as inactivated cord blood serum and in the presence of sera from preterm infants (28‐33 weeks). It is concluded that intravenous Sandoglobulin therapy may be effective in the treatment of preterm infants with severe coagulase‐negative staphylococcal infections.