HTLV-I-associated myelopathy/tropical spastic paraparesis in the United States.

HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is endemic in the Caribbean basin and Japan. Because of the close proximity of the United States to the Caribbean and the presence of HTLV-I-seropositive persons in the United States, we sought reports of patients who were HTLV-I seropositive and had a slowly progressive myelopathy. Over a 2-year period, there were 25 patients reported, 19 of whom were black and 12 of whom had been born in the United States. All patients except two had become symptomatic while living in the United States. Six patients had no apparent risk factor for acquiring HTLV-I. These data demonstrate that HAM/TSP is occurring in the United States and that the diagnosis of HAM/TSP should be considered in patients with a slowly progressive myelopathy regardless of risk factors for acquiring HTLV-I.

Growth of gram-positive and gram-negative bacteria in platelet concentrates.

In 1986 the allowable platelet storage time was reduced from 7 to 5 days because of a recent increase in septic deaths associated with platelet transfusion. In this study, the growth curves of two gram-positive and two gram-negative organisms in platelets stored for 7 days in CLX and PL-732 bags were evaluated. Platelets in CLX bags were inoculated with 10(1), 10(2), and 10(3) organisms and 10(2) organisms were introduced into PL-732 bags. Test organisms were inoculated into trypticase soy broth as a control. All four bacteria grew rapidly in trypticase soy broth, reaching 10(9) organisms per mL within 48 hours. In both CLX and PL-732 bags, the growth pattern of gram-positive organisms was generally logarithmic during the first few days of storage. A concentration of 10(8) organisms per mL was present by Day 3 or 4, after which further proliferation was inhibited by the high density of bacteria in the platelets. In PL-732 bags, the proliferation of gram-negative organisms followed a pattern similar to that of the gram-positive bacteria. However, gram-negative organisms grew less well in CLX bags.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of direct fluorescent antibody, acridine orange, wet mount, and culture for detection of Trichomonas vaginalis in women attending a public sexually transmitted diseases clinic.

To define the performance characteristics of two newer tests for Trichomonas vaginalis (TV), the authors compared direct fluorescent antibody (DFA) (mixed monoclonal antibody, Integrated Diagnostics, Inc, Berkeley, CA) and acridine orange (AO) tests to standard wet mount (WM) preparations and culture (modified Diamond medium) of vaginal wash specimens in consecutively examined women presenting to a public sexually transmitted diseases (STD) clinic. Cultures for Neisseria gonorrhoeae (GC), Chlamydia trachomatis (CT), and yeast were also performed on all patients. Of 104 women, 59 (57%) were infected with one or more pathogens. Trichomonas vaginalis was detected by WM and/or culture in 38 (37%) women and was the most prevalent infection. Of the 38 patients with TV, 95% were detected by culture, 83% by DFA, 66% by AO, and 66% by WM. An additional patient was DFA positive but negative for TV by all other methods. The sensitivity of DFA was superior to AO and WM in women with TV infection alone (96% compared to 67% and 53%, respectively). It was comparable to AO and WM in women with multiple infections (67% compared to 53% and 73%). Even in the presence of other pathogens, DFA appears to be a reasonable alternative to culture for detection of TV. In addition, DFA is rapid, easy to perform, and relatively inexpensive.

Percutaneous central venous catheter colonization with Malassezia furfur: incidence and clinical significance.

Malassezia furfur colonization of central venous catheters has been implicated in the pathogenesis of systemic infections with this lipid-dependent yeast. To determine the incidence of catheter colonization in our neonatal intensive care unit (NICU), 25 consecutively removed percutaneous central venous catheters were examined by rinsing the lumen with saline and plating the rinse fluid on Sabouraud dextrose agar overlaid with olive oil. M furfur grew from the lumina of eight catheters (32%). Surveillance skin cultures were performed in the NICU on two occasions to determine the prevalence of skin colonization with M furfur. M furfur was found on the skin of 64% of the infants. In contrast, only 3% (1/33) of healthy, nonhospitalized infants 2 to 8 weeks of age had skin colonized with M furfur. During the 5-month study period, two NICU infants had evidence of systemic infection with M furfur. We conclude that M furfur frequently colonizes both the skin and percutaneous central venous catheters in NICU infants. Further studies are needed to determine the relationship between skin colonization and catheter colonization, and the factors contributing to systemic disease with this organism.

Identification and characterization of Yersinia intermedia isolated from human feces.

Since May 1983, our laboratory has, upon request, cultured stools for Yersinia spp. by using direct plating on cefsulodin-irgasan-novobiocin agar and a 3-week cold enrichment procedure. We isolated bacteria identified as Y. intermedia from six adult patients. All isolates were recovered only by the cold enrichment procedure and misidentified as Y. enterocolitica by the API 20E system (Analytab Products, Plainview, N.Y.). Final identification was made on the basis of results obtained with conventional tube biochemical tests. The isolates were tested for the following characteristics associated with virulence in Y. enterocolitica: lack of pyrazinamidase activity, autoagglutinability, presence of a 40- to 50-megadalton plasmid, production of heat-stable enterotoxin, and mouse lethality. All isolates tested had pyrazinamidase activity, and none were autoagglutinable. However, one isolate possessed a 40-megadalton plasmid. None produced enterotoxin or were lethal for mice. Review of the medical histories of the patients revealed that four of the six had diarrhea; however, none had disease typical of that caused by Y. enterocolitica. Our data confirmed the limited pathogenic potential of Y. intermedia and suggested that its isolation was without clinical significance in our patients. Conventional biochemical tests were required for reliable identification of Y. intermedia.

Reliability of latex agglutination tests for identification of Staphylococcus aureus resistant to oxacillin.

Commercial latex agglutination tests (LATs) for the simultaneous detection of clumping factor and protein A are gaining increased acceptance as a means of identifying Staphylococcus aureus. We evaluated two LATs (Accu-Staph; Carr-Scarborough, Decatur, Ga.; Staphaurex; Wellcome, Dartford, England) with particular emphasis on their ability to correctly identify oxacillin-resistant S. aureus. We tested 59 oxacillin-resistant S. aureus, 136 oxacillin-susceptible S. aureus, and 92 coagulase-negative staphylococcal strains with the two LATs and with thermonuclease, slide clumping factor, tube coagulase, and protein A hemagglutination tests. Clumping factor and protein A were present in 96.9 and 82.1% of our S. aureus strains, respectively. Accu-Staph correctly identified 92.8% and Staphaurex correctly identified 91.3% of S. aureus strains. No significant difference in LAT positivity rates, presence of clumping factor, or presence of protein A was found between oxacillin-resistant and -susceptible S. aureus. Overall, there were 31 false-negative LATs for 20 S. aureus strains, 14 with Accu-Staph and 17 with Staphaurex. Ninety-five percent of these strains possessed either clumping factor or protein A or both when these factors were determined independently. There were five false-positive LATs for four strains of coagulase-negative staphylococci (three Staphylococcus epidermidis and one Staphylococcus warneri), four with Accu-Staph and one with Staphaurex. Clumping factor was present in one S. warneri strain. Thus, the specificities of Accu-Staph, Staphaurex, and the clumping factor test were 95.6, 98.9, and 98.9%, respectively. Our results indicated that LATs identify oxacillin-resistant and -susceptible S. aureus equally well; however, they offer no greater sensitivity or specificity than the clumping factor test for identification of S. aureus.

Rapid, direct antibiotic susceptibility testing of blood culture isolates using the Abbott Avantage system.

The Abbott Avantage (AV) is an updated version of the MS-2 system that provides antibiotic-susceptibility results in four to six hours. Although the system compared favorably with reference methods in several laboratory evaluations, little information exists regarding its performance with inocula obtained directly from blood cultures. The authors compared AV and a modified disk-diffusion test using standardized inocula obtained directly from the blood culture bottles for 58 isolates (46 patients). All isolates were also tested by the National Committee for Clinical Laboratory Standards standard disk-diffusion method, using inocula obtained from subcultures of the positive bottles. AV results for 553 antibiotic tests agreed with the direct disk results in 92.6% of the tests, and the agreement with the standard disk results was 88.2%. The concordance between direct and standard disk results was 93.5%. There were 2.2% very major, 1.8% major, and 7.8% minor discrepancies between results obtained with direct AV and standard disk methods. False sensitivity of Klebsiella pneumoniae to ampicillin and carbenicillin and induced clindamycin resistance in staphylococci were noted with AV. When one considers only the clinically meaningful antibiotic-organism combinations, direct AV is an acceptable, rapid alternative to direct disk susceptibility testing.

Role of pili in the virulence of Neisseria gonorrhoeae.

Gonococci of the colonial types that are associated with virulence, types 1 and 2, have pili that enable the bacteria both to attach in vitro to human epithelial cells and to resist phagocytosis by polymorphonuclear leukocytes. These piliated gonococci also agglutinate various mammalian and chicken erythrocytes. Gonococci of an avirulent colonial type, i.e., type 4, have no pili and neither attach to epithelial cells or erythrocytes nor resist phagocytosis. Like the type 4 bacteria, mechanically or enzymatically (trypsin) depiliated type 1 gonococci failed to attach to epithelial cells and erythrocytes and were susceptible to phagocytosis. Pili of types 1 and 2 gonococci were antigenically similar. Both type 1 gonococci and pili isolated from them induced in rabbits antibody that (i) precipitated gonococcal pili in immunodiffusion, (ii) reacted with piliated gonococci as tested by indirect immunofluorescent analysis, (iii) inhibited attachment of piliated gonococci to both human epithelial cells and erythrocytes, and (iv) opsonized piliated gonococci.