The 7.5-kb plasmid present in Chlamydia trachomatis is not essential for the growth of this microorganism

An L2 serovar of Chlamydia trachomatis, isolated from a patient with proctocolitis, has been identified that does not contain the common C. trachomatis 7.5-kb plasmid. This isolate was propagated in vitro showing that this plasmid is not required for the growth of C. trachomatis.

Molecular techniques for the detection of Chlamydia trachomatis

A DNA probe assay (PACE; Gen-Probe, San Diego, Calif.) was compared with a culture reference method for the detection of Chlamydia trachomatis. Using stock isolates of each of the 15 serovars (A to K, Ba, L1, L2, and L3) of C. trachomatis, the lower limit of sensitivity for the DNA probe ranged between 1,086 inclusion-forming units (IFU) for serovar E (Bour) to 2,930 IFU for serovar L1 (440), with the only exception being serovar C (TW-3), with which 99 IFU was detected. There was no cross-reactivity with Chlamydia psittaci (Texas turkey) and Chlamydia pneumoniae (TWAR-183). Bacterial and fungal isolates representing 14 species of normal vaginal flora as well as Neisseria gonorrhoeae gave negative results with the DNA probe when tested at a level of 1.5 X 10(7) CFU/ml. In addition, the DNA probe, a direct fluorescent-antibody stain (DFA) (MicroTrak; Syva Corp., Palo Alto, Calif.), and an enzyme-linked immunosorbent assay (Chlamydiazyme; Abbott Laboratories, North Chicago, Ill.) were compared with culture for the detection of C. trachomatis, using 196 clinical cervical samples. Of the 196 samples, 20 (10%) were culture positive. Of the 176 culture-negative samples, 1 was not evaluated by DNA probe and 4, because of a lack of cellular material, were not evaluated by DFA. The sensitivities of the DNA probe, DFA, and enzyme-linked immunosorbent assay were 60, 75, and 85%, respectively, and specificities were 95, 99, and 97%, respectively. Of the false-positive direct results, there was only one specimen with which more than one direct method was positive, and with this specimen all three direct methods were positive. The majority of false-negative results by the direct methods were from specimens which by the culture method gave <100 IFU per culture.

Direct identification of Mycobacterium tuberculosis, Mycobacterium avium, and Mycobacterium intracellulare from amplified primary cultures in BACTEC media using DNA probes

DNA probes (Gen-Probe, San Diego, Calif.) directed at the Mycobacterium tuberculosis complex and Mycobacterium avium-M. intracellulare complex were used to identify acid-fast bacilli directly from specimens grown in BACTEC 12B bottles (Becton Dickinson and Co., Towson, Md.). Clinical specimens were inoculated directly or after decontamination into a BACTEC 12B bottle, Middlebrook 7H11 agar, and Lowenstein-Jensen medium. Conventional media were incubated at 37 degrees C in 5% CO2 and examined weekly for 6 weeks. Identification of isolates grown on conventional media by standard biochemicals, morphology, and growth characteristics served as the reference method for identification. BACTEC bottles were incubated at 37 degrees C, and a growth index was taken twice a week. When a growth index of greater than or equal to 100 was reached, 1 ml of BACTEC 12B medium was put into each of three microfuge tubes which were centrifuged for 15 min at 15,000 x g. Pellets were used in hybridization reactions with an M. tuberculosis complex probe, an M. avium probe, and an M. intracellulare probe. The results of the hybridizations of the three probes with the same sample were compared, and the highest percent hybridization was divided by the average of the lower hybridization values. If this value, the derived patient ratio (DPR), was greater than or equal to 3, then the specimen was considered positive for the organism giving the highest percent hybridization. Of the 1,988 specimens cultured, the results of conventional tests for the 190 conventional culture-positive specimens were 64 M. tuberculosis, 61 M. avium, 14 M. intracellulare, 30 other Mycobacterium spp., and 25 non-acid-fast bacilli. There were four cultures that each contained two different Mycobacterium spp. Directly probing the BACTEC 12B sediment, at DPR of >/= 3 the M. tuberculosis probe identified 83% (53 of 64) of M. tuberculosis isolates, the M. avium probe identified 92% (56 of 61) M. avium isolates, and the M. intracellulare probe identified 86% (12 of 14) of M. intracellulare isolates. There were no false-positive results at this DPR level. The false-negative results from probing the sediment from the BACTEC 12B bottle could not solely be attributed to the number of organisms present, the growth index, or antimicrobial therapy.

Evaluation of a new herpes simplex virus typing reagent for tissue culture confirmation

Monoclonal antibody typing reagents for herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) from California Integrated Diagnostics, Inc. (Berkeley, CA) were compared to two other commercially available HSV monoclonal antibody typing reagents. Of the 105 specimens tested, of which 81 were positive for HSV, there was 100% agreement with all three typing reagents.

Rapid bioluminescence method for bacteriuria screening

A study was performed to evaluate the UTIscreen (Los Alamos Diagnostics, Los Alamos, N. Mex.), a rapid bioluminescence bacteriuria screen. The UTIscreen was compared with three other rapid bacteriuria screens: the Bac-T-Screen (Vitek Systems, Hazelwood, Mo.), an automated filtration device; the Chemstrip LN (Boehringer Mannheim Diagnostics, BioDynamics, Indianapolis, Ind.), an enzyme dipstick; and the Gram stain. A semiquantitative plate culture was used as the reference method. Of the 1,000 specimens tested, 276 had colony counts of greater than 10(5) CFU/ml by the culture method. Of these, the UTIscreen detected 96% (265 of 276) using greater than or equal to 5% of the integrated light output of the standard reading as a positive interpretive breakpoint, the Bac-T-Screen detected 96% (266 of 276), the Chemstrip LN detected 90% (249 of 276), and the Gram stain detected 96% (264 of 276). Of the 214 probable pathogens isolated at greater than 10(5) CFU/ml, the UTIscreen detected 95% (204 of 214), the Bac-T-Screen detected 98% (210 of 214), the Chemstrip LN detected 92% (198 of 214), and the Gram stain detected 98% (209 of 214). The predictive values of negative test results at greater than 10(5) CFU/ml for the UTIscreen, the Bac-T-Screen, the Chemstrip LN, and the Gram stain were 98, 97, 93, and 98%, respectively. The overall specificities at greater than 10(5) CFU/ml for the UTIscreen, the Bac-T-Screen, the Chemstrip LN, and the Gram stain were 70, 48, 51, and 69%, respectively. There were 532 specimens with colony counts of >10(3) CFU/ml, and of these, the UTIscreen, the Bac-T-Screen, the Chemstrip LN, and the Gram stain detected 72, 81, 76, and 73%, respectively. Of the 249 probable pathogens isolated at >10(3) CFU/ml, the UTIscreen, the Bac-T-Screen, the Chemstrip LN, and the Gram stain detected 91, 95, 89, and 93%, respectively. The overall specificities at > 10(3) CFU/ml for these methods were 79, 55, 57, and 78%, respectively. The cost per test for detection was approximately $0.50 for the Chemstrip LN. Overall, the UTIscreen is rapid and easy to perform; its sensitivity compared favorably with those of the other screening methods; it had higher specificity than the Bac-T-Screen and Chemstrip LN; and it allowed for bathing of specimen.

Comparison of a single-antigen microimmunofluorescence assay and inclusion fluorescent-antibody assay for detecting chlamydial antibodies and correlation of the results with neutralizing ability

An inclusion fluorescent-antibody assay (IFA) with McCoy cells infected with Chlamydia trachomatis serovar L2 was compared with a single-antigen (L2) microimmunofluorescence (MIF) assay for the detection of antichalmydial antibodies. A total of 562 serum specimens were tested by both assays, and sera representing a range of titers were tested for their ability to neutralize the infectivity of C. trachomatis. Overall, there was poor correlation between the two assays (r2 = 0.62). With most sera the inclusion IFA was more sensitive. There was better correlation between IFA titer and ability to neutralize the five serovars tested (L2, L3, C, E, and F) than between the MIF assay and neutralization. In summary, the IFA appeared to be more sensitive than the MIF assay for detecting antibodies to C. trachomatis.

Cloning and characterization of a Chlamydia trachomatis L3 DNA fragment that codes for an antigenic region of the major outer membrane protein and specifically hybridizes to the C- and C-related-complex serovars

Chlamydia trachomatis L3 DNA was cloned and expressed in lambda gt11. A recombinant plaque that expressed an antigen that reacted with rabbit polyclonal antichlamydial L3 serum and with two monoclonal antibodies specific for serovars L3 and I was selected from this Chlamydia genomic library. The beta-galactosidase Chlamydia fusion protein was purified by immunoaffinity chromatography and injected into mice to produce monoclonal antibodies. These monoclonal antibodies reacted by Western (immuno-) blot with both the fusion protein and the major outer membrane protein from purified L3 elementary bodies. The chlamydial DNA fragment was shown by DNA sequence analysis to be 168 base pairs in length and to correspond to the constant regions 1 and 2 and the variable segment 1 of the major outer membrane protein gene. The recombinant chlamydial DNA fragment hybridized under stringent conditions by Southern and dot blot analysis exclusively with the DNA from the C- and C-related-complex C. trachomatis serovars.

Detection of herpes simplex virus by 8 h in shell vial cultures with primary rabbit kidney cells

Shell vial (SV) cultures for herpes simplex virus using primary rabbit kidney cells stained at 8 h after inoculation were compared with 20-h SV cultures as well as conventional tissue culture. Of the 326 clinical specimens examined, conventional culture detected 67, and of these, 61 (91%) and 42 (63%) were detected by 20-h SV cultures and 8-h SV cultures, respectively.

Role of endogenous gamma interferon in host defense against Chlamydia trachomatis infections

BALB/c mice (6 to 8 weeks old) infected with Chlamydia trachomatis serovar L1 were sacrificed, and the yield of Chlamydia inclusion-forming units from the liver and lungs was measured in HeLa 229 cells. The yield of inclusion-forming units reached a peak at 3 days postinfection and then progressively declined. The mice infected with C. trachomatis had no detectable levels of gamma interferon (IFN-gamma) in their sera. However, stimulation of their spleen cells with either concanavalin A or heat-killed C. trachomatis resulted in the release of high levels of IFN-gamma (600 to 900 IU/ml) at 5 to 8 days postinfection. The increased release of IFN-gamma from the spleen cells paralleled the clearance of chlamydia from the liver and lungs. Sera and spleen cells from animals immunized with live C. trachomatis were transferred to recipient mice that were subsequently challenged with C. trachomatis. Transfer of spleen cells resulted in a reduction of the infection in the recipient animal as measured by the yield of chlamydia from the spleen, but transfer of the sera did not confer protective immunity. In addition, mice infected with C. trachomatis serovar L1 were treated with a hamster neutralizing monoclonal antibody to recombinant murine IFN-gamma (MAb-MuIFN-gamma). In the animals receiving the MAb-MuIFN-gamma, the yield of chlamydia from the lungs, spleen, and liver was significantly higher than from the control groups of mice. Histopathological analysis of tissues from the chlamydia-infected mice showed that the animals treated with the MAb-MuIFN-gamma had a significantly more extensive inflammatory reaction in their lungs, liver, and spleen.

Activation of mouse peritoneal macrophages in vitro or in vivo by recombinant murine gamma interferon inhibits the growth of Chlamydia trachomatis serovar L1

Peritoneal mouse macrophages activated in vitro with recombinant murine gamma interferon (10 ng/ml) or in vivo (10 micrograms per mouse) showed a significant decrease in the growth and yield of Chlamydia trachomatis. The restriction of the growth of C. trachomatis paralleled the expression of Iad on the macrophages. Mice that received macrophages activated in vitro with recombinant murine gamma interferon showed a significant decrease in the yield of chlamydial infection-forming units from their spleens and peritoneal fluids.

Identification of viridans streptococci by three commercial systems

The API 20S (Analytab Products, Plainview, NY), the GPI card (Vitek Systems, St. Louis, MO) and the RapSTR system (Innovative Diagnostics, Atlanta, GA) were compared with conventional biochemicals for the identification of viridans streptococci. One hundred nine clinical isolates were tested that included the following species: intermedius (38) sanguis II (20), bovis (variant) (14), mitis (14), salivarius (11), sanguis I (6), constellatus (3), mutans (2), and uberis (1). With initial testing, a correct species call was made with 72% of the isolates with the GPI card, 62% with the RapSTR, and 50% with the API 20S. Identifications of viridans streptococci group or those that needed additional biochemicals for species identification occurred with 28% of isolates with the API 20S, 8% with the RapSTR, and 9% with the GPI card. Incorrect identifications occurred with 6% of the isolates tested by the GPI card, 20% with the API 20S, and 30% with the RapSTR. Most discrepancies with the RapSTR were with 66% of the intermedius isolates, whereas most, 55%, of misidentifications with the API 20S were with sanguis II isolates. No identifications were made with 2% and 13% of isolates with the API 20S and GPI, respectively.

Restriction endonuclease analysis of DNA from Chlamydia trachomatis biovars

DNA from a total of 60 Chlamydia trachomatis isolates was examined by restriction endonuclease analysis. Strains from all established biovars and serovars were tested. There was great diversity between the mouse biovar and the lymphogranuloma venereum (LGV) and trachoma biovars. The LGV and trachoma biovar isolates generated similar fragment patterns; however, distinct fragments appeared to be unique to both biovars, thus allowing differentiation of these two major groups. In most cases, strains of the same serovar could be differentiated from one another when a battery of restriction enzymes was used. In addition, in some cases, certain restriction fragments appeared to be characteristic of strains from a particular geographical location. The DNA patterns generated by all C. trachomatis isolates differed greatly from the DNA patterns generated from the Chlamydia psittaci isolates tested, including TWAR, a human C. psittaci strain.

Protective role of magnesium in the neutralization by antibodies of Chlamydia trachomatis infectivity

Neutralization of the infectivity of Chlamydia trachomatis was assessed by using polyclonal antisera and monoclonal antibodies (MAbs). Polyclonal antisera and a species-reactive MAb as well as a subspecies-specific MAb, both of which were directed toward the major outer membrane protein of C. trachomatis, reduced the number of chlamydial inclusion-forming units in an in vitro assay. Neutralization was dependent on the presence of complement. The species-specific MAb reacted with all 15 serovars by a microimmunofluorescence assay and a dot blot enzyme-linked immunosorbent assay with heat-treated elementary bodies. On the other hand, this same MAb reacted with all serovars, except those in the C complex, by the dot blot enzyme-linked immunosorbent assay with viable organisms and neutralized in vitro all 10 serovars tested, except those in the C complex. When neutralization assays were performed in a solution containing Mg2+, neutralization by both polyclonal antisera and MAbs was significantly reduced. A dose response to Mg2+ supplied as MgSO4 revealed that all concentrations tested from 50 to 800 microM had some effect. Concentrations of greater than or equal to 400 microM MgSO4 completely abolished neutralization at the lowest dilution of polyclonal antisera and species-reactive MAb tested. Although Mg2+ also blocked the neutralization effect of the subspecies-specific MAb, this neutralization was not as complete as that observed with the species-reactive MAb. Addition of Mg2+ to the assay over the initial 45 min of incubation of C. trachomatis with MAb and complement showed that the organisms could be rescued to some extent over the first 30 min of incubation, after which time neutralization of infectivity could not be reversed. C. trachomatis treated with Mg2+, the species-reactive MAb, and complement were lethal to mice in an in vivo toxicity and infectivity assay, whereas mice injected with organisms incubated with the same MAb and complement without Mg2+ survived.

Chlamydia parasitism: ultrastructural characterization of the interaction between the chlamydial cell envelope and the host cell

Ultrastructural analysis of the growth cycles of Chlamydia trachomatis and Chlamydia psittaci showed that the chlamydial cell envelope became rigid and septated at the time of the reorganization from reticulate to elementary body. This process occurred in the immediacy of the inclusion membrane and in close proximity with the mitochondria or the endoplasmic reticulum of the host cell.

Comparison of primary rabbit kidney and MRC-5 cells and two stain procedures for herpes simplex virus detection by a shell vial centrifugation method

By using a conventional tissue culture method as a standard, four shell vial centrifugation culture (SVC) formats were compared for herpes simplex virus (HSV) detection in 300 clinical samples. Both MRC-5 and primary rabbit kidney (PRK) cells were used in the conventional and SVC systems. In addition, both a direct monoclonal fluorescent antibody to HSV (MAb-FA; Syva Corporation, Palo Alto, Calif.) and an indirect HSV polyclonal antibody-horseradish peroxidase stain (poly-HRP; Difco Laboratories, Detroit, Mich.) were used to stain shell vials of both cell types. Conventional tubes were incubated for up to 7 days with daily examination for cytopathic effect, which was confirmed as HSV by staining with an MAb-FA. Shell vials were inoculated, centrifuged, incubated for 16 to 24 h, and stained directly with MAb-FA or indirectly with a poly-HRP stain. Of the 300 specimens examined, 82 (27%) were HSV positive by conventional tissue culture. PRK cells detected 81 (99%) positive specimens, compared with 74 (90%) specimens detected with MRC-5 cells. Of the 82 positive specimens by conventional culture, the SVC formats detected 68 by MRC-5 and MAb-FA, 74 by MRC-5 and poly-HRP, 64 by PRK and MAb-FA, and 77 by PRK and poly-HRP. Therefore, PRK stained by an indirect method with poly-HRP was the most sensitive of the SVC formats tested, detecting 94% of the positive specimens.

Dependence of the in vitro antiproliferative activity of recombinant human gamma-interferon on the concentration of tryptophan in culture media

In addition to its antiviral and antibacterial activities, recombinant human gamma-interferon (rHuIFN-gamma) can exert an antiproliferative effect on human cell lines. The mechanisms involved in this antiproliferative activity are poorly understood, but it is known that IFN-gamma can induce indoleamine 2,3-dioxygenase, which enhances tryptophan metabolism and thus depletes the cellular pool of this amino acid. In the present study we have examined the effect of different tryptophan concentrations on the antiproliferative activity of rHuIFN-gamma on four human tumor cell lines, HeLa 229, HEp-2, A549, and T24. Cells were grown in the presence of rHuIFN-gamma (0.01 to 100 ng/ml) and/or tryptophan (10 to 400 micrograms/ml) for 7 days at which time they were counted. rHuIFN-gamma (4 ng/ml) inhibited the growth of A549 and T24 cells by 50%. Hep-2 and HeLa 229 cells were more sensitive to the rHuIFN-gamma induced antiproliferative effects, requiring only 0.4 ng/ml for a 50% inhibition. Addition of tryptophan to the media at concentrations from 10 to 100 micrograms/ml resulted in a significant blockage of the antiproliferative activity of rHuIFN-gamma. For example, when 50 micrograms/ml of tryptophan were added to the media, 10 times more rHuIFN-gamma (4 ng/ml) was needed to inhibit HeLa 229 cells by 50% of the control. The A549 was the most sensitive cell line to the modulatory activity of the tryptophan. Addition of 10 micrograms/ml of tryptophan changed the amount of rHuIFN-gamma needed to produce a 50% inhibition from 4 ng/ml to 100 ng/ml. In summary, in the four human tumor cell lines tested, the antiproliferative activity of rHuIFN-gamma could be modulated by the concentration of tryptophan in the media.

Recombinant murine gamma interferon inhibits Chlamydia trachomatis serovar L1 in vivo

Chlamydia trachomatis serovar L1 injected intravenously in mice resulted in systemic nonlethal infections of the animals. Treatment of mice with recombinant murine gamma interferon resulted in a decrease in the number of infectious C. trachomatis organisms recovered from the lungs, spleens, and livers as well as in a decrease of the inflammatory reaction in those organs when assessed 3 and 5 days after challenge.

Evaluation of a shell vial centrifugation method for the detection of herpes simplex virus

A MRC-5 shell vial method was compared to a MRC-5 conventional tube cell culture method in 410 specimens, 88 of which were positive for herpes simplex virus. The shell vial had a sensitivity of 92% and a specificity of 99% when compared to conventional cell culture.

Rapid identification of pathogenic Neisseria species and Branhamella catarrhalis

Two systems, the Identicult-Neisseria (IDN; Scott Laboratories, Inc., Fiskeville, R.I.) strip and the Neisseria/Haemophilus Identification Test Kit (NHI; Vitek Systems, Inc., Hazelwood, Mo.) card, were compared with the 4-h Minitek system (BBL Microbiology Systems, Cockeysville, Md.) for their ability to rapidly identify 157 pathogenic Neisseria and Branhamella catarrhalis isolates. IDN, limited in its identification to four species, when incubated at 35 degrees C for 10 min identified 99% of the isolates. However, when IDN was incubated at 22 degrees C for 20 min, it identified only 92% of the isolates. The NHI card, a rapid semiautomated system with the ability to identify 25 organisms to the species level, correctly identified all of the isolates. A test for beta-lactamase production included in the NHI card identified the 12 Neisseria gonorrhoeae and 10 B. catarrhalis beta-lactamase-positive isolates included in the study. The IDN strip (35 degrees C) and the NHI card compared favorably with the Minitek system.

The antichlamydial, antiviral, and antiproliferative activities of human gamma interferon are dependent on the integrity of the C terminus of the interferon molecule

The effects of recombinant human gamma interferon (rHuIFN-gamma; two identical monomers of 140 residues in length) and of two re-engineered C-terminal variants, rHuIFN-gamma Tetra-Ser (residues 129 to 132 replaced by serine) and rHuIFN-gamma 125 (two identical monomers of 125 residues each with the last 14 residues plus an additional alanine from the C terminus deleted), were compared in terms of several in vitro biological activities. By using three different human cell lines (HeLa 229, HEp-2, and A549), the interferons were tested for their ability to inhibit: (i) growth of Chlamydia trachomatis; (ii) replication of encephalomyocarditis virus; and (iii) cell growth. rHuIFN-gamma restricted the growth of chlamydiae to 50% of the non-IFN-treated control at concentrations ranging from 0.01 to 0.05 ng/ml, depending on the cell type assayed. One of the modified proteins, rHuIFN-gamma Tetra-Ser, also decreased the growth of chlamydiae, but it required a concentration of approximately 0.5 ng/ml to produce 50% inhibition. rHuIFN-gamma 125 had the lowest antichlamydial activity of the three IFN-gamma variants tested; concentrations of 1 to 20 ng/ml were needed to reduce the growth of C. trachomatis to 50% of that of the control. The relative antiviral and antiproliferative activities of the three IFN-gamma preparations paralleled their antichlamydial activities in these three cell lines. The antiencephalomyocarditis virus activities of rHuIFN-gamma Tetra-Ser and rHuIFN-gamma 125 were reduced by approximately 10-fold and 10(2)- to 10(3)-fold, respectively, compared with the antiviral activity of rHuIFN-gamma. Proliferation of the three cell lines was restricted to approximately 50% of the control with 0.5 to 10 ng of rHuIFN-gamma per ml. Inhibition of cell growth by rHuIFN-gamma Tetra-Ser was significant only at concentrations equal to or greater than 30 ng/ml, and the rHuIFN-gamma 125 variant did not significantly decrease the growth of any of the three cell lines at the concentrations tested. These results suggest that the C-terminal portion of rHuIFN-gamma is critical for maintaining the conformation necessary for inducing the antichlamydial, antiviral, and antiproliferative activities of the molecule.

Comparison of techniques for the selection of bacteria-free sperm preparations

The authors compared the three most commonly used sperm preparation techniques--swim-up, fall-down, and Percoll gradient--for their ability to recover highly motile sperm and minimize bacterial contamination. Eleven human semen samples collected by masturbation were used and run in parallel with the three methods. A semiquantitative bacterial analysis was performed in all samples and results expressed in colony-forming units per milliliter (CFU/ml). The Percoll gradient technique resulted in an average sperm concentration of 5.81 +/- 4.4 X 10(6) ml, and the average bacterial concentration dropped from 8.66 +/- 12.96 X 10(3) CFU/ml in semen to 0.01 +/- 0.03 X 10(3) CFU/ml. The bacterial count was not significantly different when the raw semen was compared with the swim-up or the fall-down preparations. The authors conclude that the Percoll gradient method yields an adequate sperm concentration, with high motility and improved morphology, while eliminating bacterial contamination.

Ultrastructural analysis of the anti-chlamydial activity of recombinant murine interferon-gamma

The effect of murine interferon-gamma (MuIFN-gamma) on the developmental cycle of Chlamydia trachomatis in McCoy cells was analyzed by light and electron microscopy. Addition to the culture media of 10 ng/ml of MuIFN-gamma, either 24 hr before or immediately after Chlamydia infection, resulted in a significant inhibition of the growth of this organism. Microscopic analysis showed that with both treatments the majority of microorganisms were arrested at the elementary body stage. Only a few small chlamydial inclusions were detected at 48 hr postinfection and contained predominately reticulate bodies. Furthermore, the growth of Chlamydia was arrested in cells that were treated with MuIFN-gamma at various intervals following infection. Addition of MuIFN-gamma at 8 or 12 hr after infection resulted in the arrest of chlamydial growth before initiation of reticulate body fission. When the MuIFN-gamma was added 24 hr postinfection, we could detect, by electron microscopy, inhibition at the stage of reticulate body replication.

Rotavirus gastroenteritis in southern California

The epidemiology of rotavirus infections in Southern California was analyzed over a three year period, from January 1, 1981 through December 31, 1983. Data was available from patients seen at the University of California Irvine Medical Center (UCIMC), in addition to referral testing provided to the community in Orange County. Over the 3 yr period the laboratory performed 1172 rotavirus assays. Out of these, 345 were positive for an overall positive rate of 29.4%. The 643 stool specimens from UCIMC corresponded to 508 patients, of which 31.1% (158/508) were positive for rotavirus. The majority of patients with a positive rotavirus test were under 1 yr of age (117/158), with only ten cases found in the 2-15 yr old group. The distribution of the positive rotavirus tests was similar for the female and male population. Approximately 70% of the positive results occur during October through December, with the month of November having the highest incidence. The distribution of positive rotavirus tests did not appear to correlate with either the coldest or the driest month of the year in Southern California.

Oviductal cilial phagocytosis in patients undergoing tubal reanastomosis

Chronic salpingitis has been reported in patients undergoing reversal of sterilization. For investigation of a possible microbial etiology for this process and characterization of its ultrastructural features, segments from the midportion of the fallopian tubes of five patients who underwent sterilization reversal were studied by comprehensive tubal cultures, and light and electron microscopy. Three patients undergoing sterilization by partial salpingectomy were studied as controls. Chlamydial IgG and IgM antibody titers were performed on serum samples. No microbiologic or serologic evidence for active infection by known pathogens was found. In three of the study patients mild oviductal mural fibrosis was present. However, in two other study patients chronic salpingitis with phagocytosis of cilia by luminal macrophages was demonstrated. It is suggested that if this active process persists after tubal reanastomosis, it may result in impaired oviductal function.

Evaluation of the Cellmatics and direct monoclonal fluorescence antibody staining for detection of genital chlamydial infections

Three methods for Chlamydia trachomatis detection were compared: the Cellmatics (Difco Laboratories, Detroit, MI), a commercially available tissue culture system which contains a rat cell line; a direct fluorescent Chlamydia antibody (DFA) (Microtrak, Syva Corp., Palo Alto, California) stain; and a standard tissue culture isolation method employing McCoy cells. Of the 121 specimens in the study, 20 were positive by the standard cell culture. All 20 of these specimens were also positive by the Cellmatics but only 10 were positive by DFA.

Neonatal herpes simplex virus infection occurring in second twin of an asymptomatic mother. Failure of a modern protocol

A case of neonatal herpes that occurred after vaginal delivery in the absence of genital lesions is presented. The mother had a history of drug addiction and genital herpes. Asymptomatic shedding of herpes simplex virus type 2 from the cervix was noted in the second trimester of pregnancy. Despite being followed with a protocol of close surveillance and serial culturing of the genital tract, the patient gave birth to twins, one of whom developed herpes simplex virus type 2 in the postpartum period. This report presents discussion of this case and herpes surveillance protocols.

Determination of immune status in patients with low antibody titers for rubella virus

Three assays for detection of rubella antibodies, Rubella G (fluorescence immunoassay [FIA]), Rubacell (passive hemagglutination), and Rubaquick (passive hemagglutination with rotation), were compared with hemagglutination inhibition. A total of 100 serum specimens were selected, 68 of which had an FIA value of less than or equal to 25. On initial testing, among the four tests, there was agreement for 88 specimens for assignment of rubella immune status. On repeat testing, all the results agreed by the hemagglutination inhibition, passive hemagglutination, and passive hemagglutination rotation methods, and only one discrepant specimen remained by FIA.

Effect of holding temperature on isolation of Neisseria gonorrhoeae

The effect of holding temperature on the recovery of Neisseria gonorrhoeae was studied. From 300 specimens tested, Thayer-Martin medium plates inoculated and incubated in the presence of CO2 at 35, 22, and 4 degrees C for 24 h before incubation at 35 degrees C yielded 100, 96, and 95% of all isolates ultimately recovered from 82 positive specimens. Although there was a decrease in the quantity of organisms recovered, initial incubation of specimens under refrigeration or at room temperature yielded greater than or equal to 95% of the positive specimens.

Evaluation of four anti-microbic susceptibility testing systems for gram-negative bacilli

A total of 200 clinical isolates were assayed by five anti-microbic susceptibility testing systems. Two frozen minimal inhibitory concentration (MIC) systems (MicroScan and Pasco), an automated MIC system (AMS, Vitek Systems), and the standard disk diffusion were compared with a reference broth dilution method. Organisms tested included 100 resistant clinical stock strains and 100 fresh random clinical isolates. Overall, there were 1,600 anti-microbic-organism combinations analyzed. The Pasco and MicroScan systems had no major discrepancies, the AMS system had seven, and the disk diffusion two. The number of very major discrepancies were as follows: AMS, 11; disk diffusion, 9; MicroScan, 5; Pasco, 2. Of the total 36 major or very major discrepancies in the study, 33% (12 of 36) were with an aminoglycoside and 44% (16 of 36) occurred with a second-generation cephalosporin, of which 10 of 16 were with cefamandole. Overall, there was a greater than 98.8% essential agreement with all systems compared with the reference method.

Improvement of positive blood culture detection by agitation

To evaluate the advantages of agitation in reducing the detection time and increasing the recovery rate of positive blood cultures, 1,000 three-bottle sets of tryptic soy broth on adult inpatients were analyzed. Two bottles were transiently vented, one of which was agitated (250 rpm) for 7-19 hr at 35 degrees C. The other vented bottle and the anaerobic bottle were incubated stationary at 35 degrees C. Smears and subcultures were performed 7-19 hr after collection on both agitated and nonagitated vented bottles. Subcultures were done on all bottles at 72 hr and smears were performed on the anaerobic bottle. There were 137 of 1000 (13.7%) positive cultures from 90 patients. The agitated bottle detected 112 of 137 (81.8%) positive cultures, was the first or only means of detection in 57 of 137 cultures (41.6%), and was the only positive bottle in 30 of 137 (21.9%) cultures. The nonagitated vented bottle detected 89 of 137 (65.0%) of positive cultures and was the only means of detection in 13 of 137 (9.5%), but was never the first means of detection. The anaerobic bottle detected 76 of 137 (55.5%) of positive cultures, was the first or only means of detection in 11 of 137 (8.0%), and was the first means of detection in one of 137 (0.7%) cultures. When both the agitated and nonagitated bottle were positive, the agitated bottle was positive on the average 35 hr earlier. We conclude that agitation of the vented bottle in a conventional blood culture system significantly decreases the detection time of positive blood cultures and increases the number of positive blood cultures detected.

Recovery of microorganisms from the pelvic cavity after intracervical or intrauterine artificial insemination

To assess the risk of introducing microorganisms into the peritoneal cavity during intracervical or intrauterine insemination, we cultured the cervix and semen from 19 couples before insemination and the peritoneal fluid from the female partner after insemination. The peritoneal cultures taken before hydrotubation grew organisms in one of ten intracervical inseminations and five of the nine intrauterine inseminations (P less than 0.05). In four of the five positive peritoneal cultures from the intrauterine group, the organism was also cultured from the semen specimen obtained before insemination and not from the cervical sample. Therefore, intrauterine insemination appears to increase the risk of introducing microorganisms into the upper genital tract and the peritoneal cavity. The clinical significance of this finding remains to be established.

Evaluation of five cell types for the isolation of herpes simplex virus

Five cells were evaluated in a comparative analysis for sensitivity, specificity, and rapidity in detecting the presence of herpes simplex virus HSV-1 and HSV-2. Included in this study were human embryonic kidney (HEK), rabbit kidney (RK), MRC-5, mink lung (ML), and Microtus agrestis (UMMA). A total of 274 specimens from genital, throat, skin, or other sources that were submitted for HSV isolation were used in the study. The sensitivity of the different cells was assessed by the total number of positive cultures detected by all the cells under evaluation. At 48 hr, HEK and RK detected 80% of the positives, ML detected 79%, MRC-5 detected 73%, and UMMA detected 60%. All cells tested were satisfactory; however, the choice of which cell to use for isolation of HSV depends upon the needs of the specific laboratory.

Typing of herpes simplex virus with synthetic DNA probes

Three single-stranded oligonucleotide probes, 22 bases long, homologous to unique regions of herpes simplex virus (HSV) types 1 (HSV-1) and 2 (HSV-2) and a region common to both were chemically synthesized with use of a modified phosphochloridite protocol. For hybridization experiments each probe was labeled with use of polynucleotide kinase and [gamma-32P] ATP to a specific activity of approximately 2 X 10(9) cpm/micrograms. Two hundred one clinical isolates of HSV (96 HSV-1 and 105 HSV-2) collected from vesicles in the mucocutaneous junction of the mouth or from the genital area were analyzed. There was a 99% (199 of 201) agreement between hybridization and monoclonal antibody typing; the two discrepant isolates of HSV-2 that were negative by monoclonal antibody typing were confirmed as HSV-2 by restriction endonuclease analysis. The probes detected between 10(4) and 10(5) HSV infectious units and from 150 to 600 HSV-infected Vero cells. No binding was detected between any of the three probes and isolates of cytomegalovirus, Epstein-Barr virus, and varicella-zoster virus.

The anti-chlamydial and anti-proliferative activities of recombinant murine interferon-gamma are not dependent on tryptophan concentrations

The effect of recombinant murine interferon-gamma on the growth of Chlamydia trachomatis was analyzed in a mouse fibroblast cell line (McCoy cells). Murine interferon-gamma had a very potent anti-chlamydial activity, although minimally affecting cellular proliferation. Over 95% inhibition of chlamydial inclusions was obtained at a concentration of 1 U/ml of interferon. At a concentration of 1 U/ml of murine interferon-gamma, there was minimal inhibition of the proliferative capacity of McCoy cells. Approximately 50% inhibition of cell growth was obtained with a concentration of 10 U/ml of interferon. Varying concentrations of tryptophan in the medium did not alter either the anti-chlamydial or the anti-proliferative activity of the interferon.

The anti-chlamydial and anti-proliferative activities of recombinant murine interferon-gamma are not dependent on tryptophan concentrations

The effect of recombinant murine interferon-gamma on the growth of Chlamydia trachomatis was analyzed in a mouse fibroblast cell line (McCoy cells). Murine interferon-gamma had a very potent anti-chlamydial activity, although minimally affecting cellular proliferation. Over 95% inhibition of chlamydial inclusions was obtained at a concentration of 1 U/ml of interferon. At a concentration of 1 U/ml of murine interferon-gamma, there was minimal inhibition of the proliferative capacity of McCoy cells. Approximately 50% inhibition of cell growth was obtained with a concentration of 10 U/ml of interferon. Varying concentrations of tryptophan in the medium did not alter either the anti-chlamydial or the anti-proliferative activity of the interferon.

Evaluation of Mycotrim-GU for isolation of Mycoplasma species and Ureaplasma urealyticum

The Mycotrim-GU (Hana Biologics, Berkeley, Calif.) biphasic culture system and a conventional system were compared for their ability to detect Ureaplasma urealyticum and Mycoplasma species in 100 clinical specimens. Both systems detected 18 Mycoplasma spp. isolates. The average colony detection time was 1.9 days with the Mycotrim-GU and 2.3 days with the conventional system. The Mycotrim-GU agar detected all 33 U. urealyticum isolates recovered in the study, and the conventional agar detected 31. In addition to the U. urealyticum isolates recovered from the agar, there were several specimens that, although they did not grow colonies on the agar, gave an alkaline broth change. Of these specimens, two were found with the conventional system and seven were found with the Mycotrim-GU. The average detection time of U. urealyticum colonies was 2.0 days for the conventional agar and 1.7 days for the Mycotrim-GU. The Mycotrim-GU offers several advantages over the conventional system: it is commercially available, consists of a one-flask system which is ready to use, has a significantly longer shelf life, and is cost competitive. This study showed the Mycotrim-GU to be an effective system for detecting the genital mycoplasmas.

Microorganisms in semen used for artificial insemination

The effect of freezing semen in a cryopreservative media consisting of egg yolk glycerol with or without erythromycin was tested for its effect on the viability of microorganisms present in donor semen and on sexually transmitted pathogens seeded into semen. All donor semen contained two or three species of microorganisms that could be considered skin flora. Five of ten donor semen specimens contained Ureaplasma urealyticum that was not affected by either freezing or antimicrobial treatment. Some strains of Neisseria gonorrhoeae, when seeded into semen, survived all conditions except freezing in egg yolk glycerol containing erythromycin. Chlamydia trachomatis was erradicated when erythromycin was present in the cryopreservative. There was no detectable effect of any treatment tested on the survival of herpes simplex virus.

Detection of bacteriuria and pyuria within two minutes

A study was performed to evaluate two rapid urine screening methods, Bac-T-Screen (Marion Laboratories, Inc., Kansas City, Mo.) and Chemstrip LN (Boehringer Mannheim Diagnostics, BioDynamics, Indianapolis, Ind.), for their ability to screen for bacteriuria and pyuria within 2 min. A total of 1,000 urine specimens were tested with the Bac-T-Screen and the Chemstrip LN and compared with a semiquantitative plate culture method. Of the 1,000 specimens tested, 249 had colony counts of greater than or equal to 10(5) CFU/ml by the culture method. Of these, the Bac-T-Screen detected 94.8% (236 of 249) and the Chemstrip LN detected 84.7% (210 of 249). There were 120 pure cultures of probable pathogens of which the Bac-T-Screen detected 97.5% (117 of 120) and the Chemstrip LN detected 91.7% (110 of 120). Leukocyte counts were performed on all specimens, and both methods have the ability to detect greater than 10 leukocytes per mm3 in a majority (greater than 93%) of the specimens. The cost per test for a negative screen is approximately $1.30 for the Bac-T-Screen and $0.40 for the Chemstrip LN. Overall there is a similar negative predictive value with both methods for bacteriuria and pyuria.

Interferon-induced inhibition of Chlamydia trachomatis: dissociation from antiviral and antiproliferative effects

The yield of infectious Chlamydia trachomatis was analyzed in human (HeLa) and mouse (McCoy) cell lines treated with the human interferon (IFN) subtypes IFN-alpha A and IFN-alpha D, with their hybrids [IFN-alpha AD (BglII), IFN-alpha AD (PvuII), and IFN-alpha DA (BglII)] constructed in vitro from their expression plasmids, or with IFN-beta 1 or buffy coat IFN. In HeLa cells, a significant inhibition of Chlamydia infectivity was obtained with IFN-alpha D, IFN-alpha DA (BglII), and buffy coat IFN. In McCoy cells, IFN-alpha AD (BglII) and IFN-alpha AD (PvuII) induced a strong degree of inhibition of Chlamydia infectivity. In McCoy cells, there was a correlation among the antichlamydial, antiviral, and antiproliferative activities of the different IFNs tested. In HeLa cells, however, the ability of a particular IFN subtype to inhibit Chlamydia infectivity did not always correlate with its inhibitory effects on encephalomyocarditis virus replication or with its antiproliferative activity.

Effect of the B-D Urine Culture Kit on an automated bacteriuria screen

The effect of urine collected in the B-D Urine Culture Kit (BDT; Becton, Dickinson & Co., Rutherford, N.J.) on the Autobac urine screen (General Diagnostics, Warner-Lambert Co., Morris Plains, N.J.) was investigated. Upon collection, 1,000 clean-voided urine specimens were divided into sterile urine tubes and BDTs. Within 24 h of collection, urine from each tube was cultured by a semiquantitative plate method and screened by the Autobac system. Overall, when screened by the Autobac system, urine collected in the BDT gave fewer false-positive results: 14.4 compared with 22.7% from the sterile urine tubes. However, in comparison with the sterile urine tubes, the BDT false-negative rate was 10.5 versus 4.7%, the detection time was longer, and the cost was increased.

Ultrastructural analysis of the growth cycle of Chlamydia trachomatis in mouse cells treated with recombinant human alpha-interferons

The effect of two recombinant human hybrid interferons (IFNs), IFN-alpha AD (BglII) and IFN-alpha DA (BglII), on the growth cycle of Chlamydia trachomatis in a murine (McCoy) cell line was investigated. Ultrastructural analysis indicated that IFN-alpha AD inhibited the growth of chlamydia while IFN-alpha DA-treated cells did not significantly differ from the control monolayers. Treatment of the chlamydia-infected monolayers with IFN-alpha AD resulted in an inhibition in the transformation of elementary bodies to reticulate bodies with a consequent marked decrease in the number of chlamydia inclusions. Furthermore, chlamydial inclusions in the IFN-alpha AD-treated cells contained fewer and more immature chlamydial forms than the control or the IFN-alpha DA-treated cells. Secondary infection occurred in the IFN-alpha DA and in the control monolayer, but no such phenomena was detected in the IFN-alpha AD-treated McCoy cells indicating a loss of infectivity of the chlamydial organisms. From this study it can be concluded that purified recombinant human hybrid IFNs may exert an inhibitory effect on the growth cycle of C. trachomatis in a mouse cell line. This inhibition occurs primarily at the point of transformation from elementary to reticulate body.

Hemagglutination treponemal test for syphilis

Sera from 290 hospital patients were tested to compare the sensitivity, specificity, and reproducibility of the hemagglutination treponemal test for syphilis (HATTS) with the fluorescent treponemal antibody absorption test (FTA-ABS). Complete agreement was obtained between the methods when 142 syphilitic sera from patients with various stages of syphilis were tested. By using clinical histories, the specificity with 148 nonsyphilitic sera was determined to be 100% for the HATTS and 96.6% (143 of 148) for the FTA-ABS. Satisfactory reproducibility was obtained with both methods. Compared with the FTA-ABS, the HATTS was more specific, easier, and more economical to perform. We therefore recommend the HATTS as a suitable alternative to the FTA-ABS.

Rapid detection of positive blood cultures

A study of 16,108 blood cultures investigated the value of performing early smears in addition to the inspection of early subcultures after 12 h of incubation. The early smear and subculture detected 44.6% of 1,236 positive cultures; of those detected by the early subculture, 57.3% grew after 12 h of incubation.

Evaluation of a two-minute test for urine screening

A study was conducted to evaluate the ability of a urine filtration system (Bac-T-Screen, Marion Laboratories, Inc., Kansas City, Mo.) to detect negative urine cultures within 2 min. A total of 1,000 urine specimens were tested with the Bac-T-Screen and compared with a standard semiquantitative culture plate method and the Autobac system (General Diagnostics, Warner-Lambert Co., Morris Plains, N.J.). Of the 1,000 clean voided urine specimens tested, 246 specimens had colony counts greater than or equal to 10(5) CFU/ml by the culture plate method. Of these, the Bac-T-Screen detected 65.4% (161 of 246), and the Autobac detected 63.0% (155 of 246). When pure cultures of diphtheroids, lactobacilli, and viridans streptococci other than group D and cultures containing multiple organisms were considered to be contaminants and, therefore, were excluded, there were 106 pure cultures of probable pathogens of which the Bac-T-Screen detected 76.4% (81 of 106) and the Autobac detected 90.6% (96 of 106). Some 133 specimens were uninterpretable with the Bac-T-Screen because 36 clogged the filter and 97 left a residual pigment on the filter. A majority of those clogging the filter (69.4%) had positive plate counts, whereas the majority of the pigmented urines had negative plate counts. Of those urine specimens tested. 754 were negative by the culture plate method. The false-positive rates for Bac-T-Screen and Autobac were 16.2 and 5.8%, respectively. As a urine screen, the Bac-T-Screen has a negative predictive value comparable to the Autobac system and has the advantage of being a 2-min test.

Characterization of Chlamydia DNA by restriction endonuclease cleavage

The DNA from six serovars of Chlamydia trachomatis, lymphogranuloma venereum (LGV) I, LGV II, LGV III, B, C, and D, and from Chlamydia psittaci was extracted, treated with restriction endonuclease enzymes, and run on agarose gels. By using this technique, the DNA of C. trachomatis could be clearly differentiated from C. psittaci DNA. A comparison of the DNA from the different serovars of C. trachomatis revealed similar patterns with and without detectable differences. LGV I, LGV II, LGV III, B, and C revealed no differences when treated with BamHI, HaeIII, XbaI, and XhoI. LGV III DNA, when cleaved with EcoRI and HhaI, had a major band migrating faster than the other two LGV serovars. Serovar D had a different pattern from all other strains tested when cleaved with BamHI, EcoRI, HhaI, HincI, and XhoI. When treated with SacI and HgaI, LGV II displayed a unique band not seen in the other LGV serovars. Differences in strains could be attributed to both chromosomal and plasmid DNA.

Comparison of cultureset to a conventional tissue culture-fluorescent-antibody technique for isolation and identification of herpes simplex virus

The isolation and identification of herpes simplex virus types 1 and 2 from clinical specimens with a 48-h system was compared with a conventional tissue culture detection method.

Fluorescence immunoassay and passive latex agglutination as alternatives to hemagglutination inhibition for determining rubella immune status

Three different assays for detection of rubella antibodies, hemagglutination inhibition (HAI), fluorescence immunoassay (FIA), and passive latex agglutination (PLA) were used to test 297 human serum samples. Overall agreements for immune status were as follows: HAI versus FIA, 95.3% (283 of 297); HAI versus PLA (1:10 dilution), 96.3% (286 of 297); HAI versus PLA (undiluted), 93.9% (279 of 297); PLA (1:10 dilution) versus FIA, 94.9% (282 of 297); and PLA (undiluted) versus FIA, 97.9% (291 of 297). The HAI test is the most time consuming, subjective, and technically difficult to perform. The FIA and PLA tests are very rapid and less labor intensive. In addition, the FIA offers an objective determination of the patient's rubella antibody level.