Color-changing Units Research Articles

In vitro detection of Mycoplasma fermentans binding to B-lymphocytes in fresh peripheral blood using flow cytometry.

Previous reports have shown, using fluorescent probes conjugated to the organism, that Mycoplasma fermentans fuses with about 12% of peripheral blood lymphocytes. However, no lymphocyte subset was specified. To elucidate the specific subset of lymphocytes involved, we developed a three-color flow cytometric assay to detect M. fermentans binding to fresh peripheral blood cells. In our assay, two strains of M. fermentans were grown in SP4 glucose broth, mixed with fresh whole blood samples (n > 20), and incubated at 37 degrees C. The blood samples were then stained with a polyclonal antibody to M. fermentans, a monoclonal antibody to B-lymphocytes (CD19), and a monoclonal antibody to T-lymphocytes (CD3). Using three-color flow cytometry, we obtained data confirming binding of M. fermentans to 10%-15% of peripheral blood lymphocytes with minimal granulocyte or monocyte staining detected. Flow cytometric analysis showed that early binding appears predominantly directed towards B-lymphocytes (86.7 +/- 9.0%), and that this binding could not be blocked by antibodies directed towards common B lymphocyte cell surface antigens. M. fermentans binding to B-lymphocytes occurred within 5 min of in vitro inoculation, reached a maximum within 30-60 min (94-97%), and thereafter plateaued. The binding was concentration dependent over a three log dilution using 10(3) color changing units as standard. Binding to T-lymphocytes was minimal (<5% positive). B lineage tumor cells or peripheral blood B cells obtained from HIV infected individuals demonstrated reduced binding of M. fermentans. This assay provides a good method to study the cellular interactions of mycoplasma and may help to elucidate pathogenic mechanisms of mycoplasma infections.

Standardized Method of Aerosol Challenge for Testing the Efficacy of Mycoplasma gallisepticum Vaccines

A special chamber was constructed with the goal of controlling the process of aerosol infection of chickens with Mycoplasma gallisepticum (MG). The virulent Australian MG field strain Ap3AS was used in each of three experiments. The response to infection of layer-strain pullets was measured serologically, by the incidence and severity of gross lesions in tracheas and air sacs, and by the relative numbers of MG isolated from tracheas and air sacs 2 wk after challenge. In two of the experiments tracheal sections were assessed microscopically. Exposure to a nebulized, undiluted broth culture of MG for 10, 20, or 30 min produced uniformly severe lesions and serological responses. By contrast, results were less severe and less consistent when doses of up to 10(8) color-changing units (CCU) were injected directly into the abdominal air sacs. Gross air sac lesions were consistently produced in almost all pullets by exposure to an infectious aerosol containing 10(2)-10(3) CCU/liter of air for 10 min and an air flow rate of 40 liters/min. This can be achieved by nebulizing a 10(-3) dilution of a fresh, early stationary phase culture of MG strain Ap3AS. However, under the conditions of these experiments, this dose did not produce significant gross or histologic lesions in the trachea.

Experimentally induced septic arthritis in chimpanzees infected with Mycoplasma hominis, Mycoplasma pneumoniae, and Ureaplasma urealyticum.

Mycoplasma hominis was isolated in pure culture from septic synovial aspirates from an individual (patient A) during 16 different bouts of exacerbation over a 70-month period of observation. Two isolates, 10(7) and also 10(6) color-changing units (CCU) of the 1620 isolate and 5 x 10(4) CCU of the 1628 isolate, caused inflammation in chimpanzees inoculated intraarticularly. Inflammation was also induced with 10(7) CCU of the 2010B isolate, serovar VII of Ureaplasma urealyticum, recovered from an agammaglobulinemic individual (patient B) with septic polyarthritis and with 3 x 10(6) CCU of the PI-1428 isolate of Mycoplasma pneumoniae. Inflammation persisted for up to 36 days and was self-limiting. The aspirates contained up to 220,000 white blood cells/mm3 and up to 10(7) CCU/mL. There was good correlation between the severity of inflammation and the numbers of organisms, but antibody was not detected in aspirates during the peak severity of disease. As the numbers of organisms, decreased, detectable levels of antibody increased, thus suggesting that antibody may have been bound to antigen. Chimpanzees previously infected with either the 1628 isolate of M. hominis or the 2010B isolate of U. urealyticum were protected on challenge with > 100 times the minimal dose causing arthritis. Chimpanzees showed little or no inflammation when inoculated intraarticularly with 5 x 10(8) CCU of the type strain PG-21 of M. hominis or with the type strain CO of U. urealyticum or when inoculated intravenously with 3 x 10(8) CCU of the arthrogenic 1620 isolate of M. hominis.

Ureaplasma diversum infection in vitro alters prostaglandin E2 and prostaglandin F2a production by bovine endometrial cells without affecting cell viability.

Bovine epithelial and stromal cells of the endometrium were inoculated with Ureaplasma diversum, pathogenic strain 2312, at 10(6) or 10(3) color-changing units (ccu)/ml in the presence of 1% fetal bovine serum (depleted of steroids by dextran-charcoal treatment) to assess the effect of infection on prostaglandin biosynthesis. When the inoculum of U. diversum was 10(6) ccu/ml, the concentration of U. diversum in the culture medium decreased with time. U. diversum was found on the epithelial and stromal cell monolayers, increasing in titer 100-fold, indicating that attachment and eventually growth occurred. When the inoculum was 10(3) ccu/ml, the titer of U. diversum remained the same or increased in the supernatant and increased on epithelial and stromal cells. The effect of infection was evaluated by measurement of the primary prostaglandin produced by each cell type, prostaglandin F2a for epithelial cells and prostaglandin E2 for stromal cells. Infection with U. diversum significantly decreased prostaglandin F2a accumulation, by 44.7% +/- 6.0% at 10(6) ccu/ml (P < or = 0.005) and 15.8% +/- 5.3% at 10(3) ccu/ml (P < or = 0.05) in epithelial cells. Prostaglandin E2 accumulation by stromal cells was decreased by 34.0% +/- 4.0% at 10(6) ccu/ml (P < or = 0.001) and by 13.5% +/- 2.7% at 10(3) ccu/ml (P < or = 0.005). Infection with 10(6) ccu/ml did not alter endometrial cell viability, as shown by protein measurement, trypan blue dye exclusion, and cell plating efficiency tests. Thus, alterations in prostaglandin production were not due to cell deterioration. These observations suggest that U. diversum can alter prostaglandin E2 and prostaglandin F2a patterns in primary cultures of bovine endometrial cells without affecting cell viability.

Rapid, sensitive PCR-based detection of mycoplasmas in simulated samples of animal sera.

A fast and simple method to detect mycoplasmal contamination in simulated samples of animal sera by using a PCR was developed. The following five mycoplasma species that are major cell culture contaminants belonging to the class Mollicutes were investigated: Mycoplasma arginini, Acholeplasma laidlawii, Mycoplasma hyorhinis, Mycoplasma orale, and Mycoplasma fermentans. After a concentration step involving seeded sera, genus-specific primers were used to amplify a 717-bp DNA fragment within the 16S rRNA gene of mycoplasmas. In a second step, the universal PCR was followed by amplification of variable regions of the 16S rRNA gene by using species-specific primers, which allowed identification of contaminant mycoplasmas. With this method, 10 fg of purified DNA and 1 to 10 color-changing units of mycoplasmas could be detected. Since the sensitivity of the assay was increased 10-fold when the amplification products were hybridized with an internal mycoplasma-specific 32P-labelled oligonucleotide probe, a detection limit of 1 to 10 genome copies per PCR sample was obtained. This highly sensitive, specific, and simple assay may be a useful alternative to methods currently used to detect mycoplasmas in animal sera.

Development and evaluation of the polymerase chain reaction method for diagnosis of Mycoplasma gallisepticum infection in chickens

A polymerase chain reaction (PCR) method specific for Mycoplasma gallisepticum (MG) was evaluated. The PCR method was found to detect as few as two colour changing units (CCU) of MG and did not give false positive reactions with other avian mycoplasmas. In chickens inoculated with either MG or Mycoplasma synoviae (MS), the PCR method was found to closely correlate with MG culture reisolation methods in chicken intranasally inoculated with MG. all chickens inoculated with MS tested negative using the MG PCR method.

Aerosol vaccination of pigs against Mycoplasma hyopneumoniae infection

Summary Aerosol vaccination is used effectively to immunize poultry against Newcastle disease, but to the authors’ knowledge, this vaccination procedure is not well studied in other species. The efficacy of im and aerosol vaccination of pigs against Mycoplasma hyopneumoniae infection was evaluated. Twenty-one pigs from a Mycoplasma-free herd were randomly allotted by litter and body weight into 3 groups. One group was given aerosolized phosphate-buffered saline solution (pbss) by inhalation. The second group (aero) was given aerosolized M hyopneumoniae vaccine by inhalation. The third group (im) was given the same vaccine by im injection. Vaccination by im administration was repeated once, and aerosol vaccination was repeated twice at 2-week intervals. Two weeks after the last vaccination, all pigs were intra-tracheally challenge-exposed with 3 ml of broth culture containing 107 color-changing units (ccu) of a low-passage strain of virulent M hyopneumoniae. Pigs were observed daily for coughing. Four weeks after challenge exposure, all pigs were necropsied. Percentage of lung affected by gross pneumonia was measured, bronchioalveolar lavage fluid (balf) cells were counted, and quantitative culture for mycoplasmas was performed on lung sections. Additionally, M hyopneumoniae-specific antibodies were measured in prevaccination, postvaccination, and postchallenge-exposure serum and balf by use of indirect elisa. Mean prevalence of persistent coughing in pigs of the aero group (4.6 d/pig) was not different from that in pigs of the pbss group (3.7 d/pig). Prevalence of coughing in im vaccinated pigs (1.0 d/ pig) was lower (P &lt; 0.05) than that in pigs of the pbss group. Mean gross lung lesion scores and balf cell counts were not different between the aero (15% pneumonia, 5,233 cells/μl) and pbss (11% pneumonia, 3,022 cells/μ1) groups, but were lower (P &lt; 0.05) in the im group (1.5% pneumonia, 400 cells/μl) than in the pbss group. Mean lung mycoplasmal counts were not significantly (P &lt; 0.05) different among the pbss (105.6 CCU/g), aero (105.3 CCU/g), and im (103.3 CCU/g) groups. Postvaccination M hyopneumoniae-specific IgG or IgA was not detectable in balf after either vaccination procedure. Postvaccination M hyopneumoniae-specific serum IgG concentration was not different among the 3 groups. Postchallenge exposure M hyopneumoniae-specific IgG and IgA were detectable in balf of all pigs, but were not different among the 3 treatment groups. Postchallenge exposure-specific serum IgG concentration was not different between the pbss (mean OD, 0.739) and aero (mean OD, 0.672) groups, but was higher (P &lt; 0.05) in the im group (mean OD, 1.185) than in the pbss group. Aerosol vaccination failed to induce local and systemic antibody responses detectable by elisa, and failed to protect pigs against mycoplasmal pneumonia. Intramuscular vaccination failed to induce local and systemic antibody responses detectable by elisa, but substantially reduced the clinical signs and lesions caused by challenge exposure to virulent M hyopneumoniae.

Experimentally induced Mycoplasma pneumoniae pneumonia in chimpanzees

Eight chimpanzees were examined. Two served as negative control and six inoculated with Mycoplasma pneumoniae became colonized. Colonization persisted for 28-68, 16-50 and 21 days with an average duration of 47, 32.5 and 21 days in the oropharyngeal, tracheal and lung tissues, respectively. Mycoplasma titers ranged from 108 to 101 color-changing units per specimen during the course of the infections. Seroconversion occurred within 12-15 days and peak antibody titers ranged from 1.256 to 1.1024 and developed between days 28 and 48 post-inoculation. Positive cold agglutinin titers were detected between 12 to 15 days and peak titers ranged from 1:80 to 1:640. Significant increases in sIgA and IgG immunoglobulin antibody levels were detected in lung lavage fluids. Unlike the many other experimentally infected animals examined, chimpanzees infected with M. pneumoniae had positive X-ray findings, developed cold agglutinins and showed overt signs of disease. These signs include persistent cough, low grade fever, rhinitis, oropharyngitis, diarrhea, and loss of appetite. Peak severity of disease corresponded with peak lung colonization, and the detection of cold agglutinins and positive X-ray findings. The microbiological, serological and clinical aspects of pneumonia induced in chimpanzees was similar to naturally occurring primary atypical pneumonia in humans.

Comparison of pathological signs of disease in specific-pathogen-free calves after inoculation of the respiratory tract with Ureaplasma diversum or Mycoplasma canis

To confirm the pathogenic role of Ureaplasma diversum in respiratory disease of calves, we inoculated caesarean-delivered, colostrum-deprived calves intranasally with a dose of 10(7) colour-changing units (CCU) or endobronchially with a dose of 10(10) CCU. Clinical signs of respiratory disease were not observed, but in the endobronchially inoculated calves, thick cuffs of round cells surrounded the bronchi, bronchioli and blood vessels, and a lobular catarrhal pneumonia developed. It was concluded that the pathogenicity of U. diversum can be demonstrated after endobronchial but not after intranasal inoculation. Similar calves were inoculated endobronchially with a dose of 2 x 10(10) colony-forming units of Mycoplasma canis. Clinical signs of respiratory disease were not observed. At day 2 after inoculation, only slight pathological signs of respiratory disease were detected, and these disappeared at day 9. M. canis was not recovered from the lungs. Hence, M. canis could not be clearly identified as a pathogen in respiratory disease of calves. By comparing the results of the various experiments, we concluded that thin cuffs of round cells in the lungs can indicate mycoplasma infections, but that these are not necessarily pathognomonic.

Identification of Mycoplasma hyopneumoniae with a DNA probe.

From a genomic library of Mycoplasma hyopneumoniae a 1.3 kb DNA fragment was cloned which showed specific Southern hybridization and dot hybridization with the type strain of several porcine and bovine Mycoplasma species. This probe selectively recognized M. hyopneumoniae sequences in purified DNA or in broth-grown organisms. The 35S-labelled probe could detect as little as 100 pg of DNA or 10(5) colour changing units. This is a possible alternative diagnostic procedure for enzootic pneumonia of pigs.

Safety of temperature sensitive mutant Mycoplasma gallisepticum vaccine

A temperature sensitive (ts) vaccine strain designated ts-11 was selected after exposure of a low passage culture of the immunogenic Australian field isolate (strain 80083) of Mycoplasma gallisepticum to 100 mg/ml of N-methyl-N-nitro-N-nitrosoguanidine. Viable counts (assayed as colour changing units (CCU)/25 microliters) of a thawed stock culture of ts-11 were typically log10 3 to log10 5 higher when incubated at 33 degrees C (the permissive temperature) than duplicate viable counts incubated at 39.5 degrees C (the restrictive temperature). Doses of approximately 2 x 10(7) CCU of ts-11 caused no gross lesions or loss of egg production when inoculated into the air sacs of susceptible chickens and no clinical or pathological signs of sinusitis when inoculated into the infraorbital sinuses of susceptible turkey poults, whereas the parent strain 80083 was demonstrably pathogenic. However, 1 of 10 poults inoculated intra-abdominally with approximately 2 x 10(7) CCU of ts-11 did show signs of mild airsacculitis. Eight-week-old pullets were vaccinated by eye drop with up to 1.4 x 10(7) CCU of ts-11 and simultaneously subjected to several stressful management practices, without apparent ill effects. Administration by coarse aerosol of 5 ml of ts-11 vaccine/25 day-old broilers, with or without 25 doses of infectious bronchitis virus vaccine caused no obvious signs of respiratory disease. The non virulent ts phenotype was maintained after 3 passages of strain ts-11 in chickens. Chickens vaccinated 3 weeks previously with ts-11 or with strain 80083 were placed in contact with susceptible chickens for a period of 2 weeks.(ABSTRACT TRUNCATED AT 250 WORDS)

The establishment and persistence of Ureaplasma urealyticum in oestradiol-treated female mice.

Administration of oestradiol to three strains of female mice induced the oestrous phase of the reproductive cycle in which there are few or no polymorphonuclear leucocytes (PMNL) in vaginal smears. This treatment rendered the mice susceptible to genital tract colonisation by serotype 8 of Ureaplasma urealyticum, inoculated intravaginally. BALB/c mice were the most susceptible, all of 10 becoming colonised; two other strains were less susceptible and untreated mice were resistant. The numbers of ureaplasmas recovered from the vagina ranged from 10(2) to 10(7) colour-changing units (ccu)/ml, irrespective of the strain of mice, and in some there was spread to the uterine horns and ovaries, and to the spleen in one mouse. Vaginal colonisation persisted for 21-163 days and subsequent failure to recover the organisms seemed to be associated with re-establishment of the oestrous cycle. There was no evidence of a genital tract PMNL response but some of the mice developed a four-fold or greater antibody response, measured by the metabolism-inhibition technique. This, however, was insufficient to protect mice against recolonization by the same serotype of U. urealyticum.

Factors influencing the in-vitro sensitivity of Ureaplasma urealyticum to tetracyclines.

The sensitivity of 23 strains of Ureaplasma urealyticum to doxycycline was measured by a metabolism-inhibition technique. The minimal inhibitory concentrations were not influenced by using, as inocula in the tests, organisms either directly from the patient or after culture, providing that the numbers of organisms in the inocula were about the same in both. All the strains were sensitive to doxycycline but an apparent increase in the resistance of the cultured organisms occurred when the number, expressed as colour-changing units (ccu), in the inoculum was 10(5) or more/ml. Tests may be undertaken on cultured organisms of U. urealyticum but it is recommended that a standard inoculum of 10(3)-10(4) ccu/ml should be used.

Incidence of Ureaplasma urealyticum in endourethral swabs compared with first voided urine from men.

The incidence of Ureaplasma urealyticum in endourethral swabs was compared with that in first voided urine specimens from 171 male patients. The organism was isolated from the urethras of 72 (42%) and from the urine of 66 (39%). The interval since last voiding urine did not significantly influence the incidence of infection or ureaplasma counts in either type of specimen. Urethritis was strongly associated with ureaplasma counts of greater than or equal to 5 x 10(5) colour changing units (ccu)/ml in the urethra and greater than or equal to 5 x 10(3) ccu/ml in urine.

A DNA probe for detecting Mycoplasma genitalium in clinical specimens

Despite decades of careful study, the etiologies of all cases of pelvic inflammatory disease (PID) and non-gonococcal urethritis (NGU) have yet to be described. Mycoplasma genitalium is a newly described organism which has been implicated as a cause of both PID and NGU. Because of fastidious growth requirements, prolonged incubation time and frequent overgrowth in clinical specimens by Mycoplasma hominis, non-culture methods need to be developed for its detection. We have cloned M. genitalium DNA by transfection into Escherichia coli using M13 as the vector. Using these segments as templates, we synthesized radiolabelled cDNAs that were tested for specific hybridization with M. genitalium, and clinically isolated genital mycoplasmas presumptively identified as M. hominis, and Ureaplasma urealyticum. A 256 base-pair segment was found to hybridize with M. genitalium with a sensitivity of 10 2 colour-changing units (CCUs). No cross-hybridization was observed with M. hominis, and cross-hybridization was observed only with large concentrations (>10 6 CCUs) of U. urealyticum. Because of our choice of M13 as the vector, which contains the Lac Operon of E. coli, slight hybridization occurred with E. coli as well. This cDNA can be used against clinical specimens to determine the ecologic niche and spectrum of disease caused by M. genitalium.

Enzyme immunoassay for detection of Mycoplasma bovis antigens in bull semen and preputial washings.

A capture enzyme immunoassay was developed for the detection of Mycoplasma bovis antigens in bull semen or preputial washings. IgG prepared from rabbits immunised with M bovis was passively adsorped to 96-well polystyrene plates. This antibody captured M bovis antigens which were then detected by using an IgG preparation from an immunised cow and murine monoclonal antibody to the bovine L-chain conjugated with horseradish peroxidase. The sensitivity of the assay was approximately 200 colour changing units (ccu)/ml and the specificity was excellent in that other species of mycoplasma, ureaplasma or acholeplasma did not react. A blind study of bull semen experimentally contaminated with M bovis detected all specimens with more than 200 ccu/ml.

Morbidity after termination of pregnancy in first trimester.

The outcome of termination of pregnancy was observed in relation to the preoperative clinical and microbiological findings in 167 women attending a day care abortion unit in Liverpool. Before termination, Chlamydia trachomatis was isolated from the cervix of 19 (11%) of the patients and high counts (greater than 10(4) colour changing units (ccu) per ml of specimen) of mycoplasmas were found in 30 (18%). Coexistent infections with chlamydiae and high counts of mycoplasmas occurred in only seven (4%) women. Trichomonas vaginalis, yeasts, or pathogenic bacteria were found in vaginal swabs from 30 (18%) women. After undergoing termination, seven (4%) women developed pelvic inflammatory disease (PID), five (71%) of whom had yielded C trachomatis before undergoing termination. A further 13 (8%) patients developed minor morbidity of the upper genital tract; high count mycoplasmal infection had been found in seven (54%) and chlamydial infection in three (23%) of these women before termination. In contrast, C trachomatis had been isolated from only 11 (8%) and high counts of mycoplasmas from 23 (16%) of the 147 women who had uneventful recoveries after undergoing termination. No correlation was apparent between the presence of vaginal pathogens before termination and the development of untoward sequelae postoperatively. Neither the history nor clinical examination before termination would have indicated that chlamydial or mycoplasmal infections were present, or that postoperative complications were likely to occur. Abnormal cervical cytology, however, was found in 86 (52%) of women overall, including 15 (79%) of the 19 women with chlamydial infection.

The Prevalence and Level of Colonisation by Mycoplasma Dispar and other Mycoplasmas on Calf Rearing Farms

The prevalence and level of colonisation by respiratory mycoplasmas, especially by Mycoplasma dispar (M. dispar), in calves on 24 Finnish calf rearing farms were studied by using nasal swabs. A minimum of 5 calves from each farm was examined and 91.3 % of the 206 calves examined were 1 to 5 months old. Nine herds were selected on account a diagnosed respiratory disease problem, the others without anamnestic knowledge of their health condition. All 24 farms and 96.1 % of the calves examined were found to harbour one or more species of mycoplasma. M. dispar, M. bovirhinis and Acholeplasma laidlawii were isolated from 23, 19 and 3 farms or from 91.7, 51.9 and 3.4 % of the calves investigated, respectively. The prevalence for M. dispar was 97.8 % and the geometric mean titer 4.9 log10 color changing units (ccu) among 1- to 5-month old calves belonging to the infected farms. The prevalence in the age-group of 6- to 12-month old calves was significantly lower (40 %). No significant difference was found in the level of colonisation by M. dispar among the one-month age-groups of the 1- to 5-month old calves. A high degree of colonisation among 1- to 2-month old calves was indicative of the high ability of M. dispar to spread and colonise the respiratory pathway of young calves in the conditions described. The same state still prevailing in calves aged 4 to 5 months supported the concept of a relatively long duration of a heavy colonisation by this mycoplasma. The prevalence of M. bovirhinis among 1-to 5-month old calves was lower than that of M. dispar. Any decrease in the level of colonisation of M. bovirhinis could not be demonstrated in older calves. The titer levels of both M. dispar and M. bovirhinis as well as the prevalence of M. bovirhinis were significantly higher in herds having a current respiratory disease problem than in healthy or mildly affected herds. The same relationship applied to the husbandry method of common pens as compared with individual pens. A causal relationship of increased colonisation level, either as cause or effect, to the respiratory disease is suggested, as well as a probably more indirect one to the common pen husbandry type.

Growth and interaction of Mycoplasma bovirhinis and Mycoplasma dispar in vitro

Two mycoplasmas were grown in pure and mixed cultures in glucose calf-serum broth with initial pH 7.8. Sensitivity to pH was also tested. The main data for Mycoplasma bovirhinis and Mycoplasma dispar, respectively, in pure cultures were as follows: lag phase, days: <1, 1–2; log phase: 1–2, 1–4; relatively stationary phase: 0–1, 2–4; decline phase (to the extent roughly logarithmic): 2–6, 5–10; maximal titers: 5 × 10 7 to 10 9, 5 × 10 6 to 10 8 color changing units per 0.2 ml; highest pH, approximately, at which decline started: 7.7 and 7.0; definitely toxic initial pH: 5.6, 6.8; relative production of acidity; less, more. Decline either shortly ended in loss of viability or, correlated with higher pH levels, led to a prolonged maintenance in lower numbers. The decline of M. bovirhinis was postulated to be essentially caused by an autotoxic product/products other than H +. In mixed cultures an antagonistic effect due to the faster growing M. bovirhinis against M. dispar was recorded. The effect varied according to the initial numbers of organisms and their ratio. Two mechanisms seemed to be active: 1. decrease of pH somewhat below neutrality led to the death of the sensitive M. dispar; 2. M. dispar, when present in relatively high initial numbers, was inhibited by M. bovirhinis during the latter's logarithmic growth at pH-levels above 7.0, the inhibition ending shortly afterwards. A rapidly inactivated product/products of M. bovirhinis metabolism, inhibitory to M. dispar was posited. The results offer an improved insight into diagnostic practices for M. dispar.

Prevalence of Chlamydia trachomatis and other micro-organisms in women seeking abortions in Pittsburgh, Pennsylvania, United States of America.

The prevalence of Chlamydia trachomatis, Ureaplasma urealyticum, Mycoplasma hominis, group B streptococcus, herpes simplex virus, and Neisseria gonorrhoeae from cervical cultures obtained from 210 women seeking abortion in Pittsburgh, Pennsylvania, United States of America was 9.3%, 72.9%, 25.2%, 4.3%, 0.9%, and 0.9% respectively. Cultures from 40/203 (19.7%) patients failed to produce any of these organisms. C trachomatis isolation was not associated with age, race, marital status, average family income, number of sexual partners, history of gonorrhoea or syphilis, or previous pregnancies, live births, or abortions, and 82.4% of women with chlamydial infections had had no urogenital symptoms in the preceding six months. The highest concentration of U urealyticum was 10(5) colour changing units (ccu)/ml, and about half of the positive ureaplasma cultures produced less than 10(3) ccu/ml of this organism. Screening for C trachomatis, is encouraged to prevent neonatal morbidity and the common complication of pelvic inflammatory disease after abortion.