Methodologic investigations and prevalence of genital mycoplasmas in pregnancy

Vaginal flora changes associated with Mycoplasma hominis

OBJECTIVE

The aim of this study was to investigate any association between vaginal carriage of Mycoplasma hominis and genital signs and symptoms, other microbial findings, and some risk behavior factors in women with and without bacterial vaginosis.

STUDY DESIGN

Women who had attended two family planning clinics and a youth clinic for contraceptive advice were divided depending on the result of vaginal culture for Mycoplasma hominis and the occurrence of bacterial vaginosis. The study population included 123 (12.3%) women who harbored Mycoplasma hominis. Those 873 (87.7%) with a negative culture for Mycoplasma hominis served as a comparison group. In the former group, 50 (40.7%) had bacterial vaginosis, which was also the case in 81 (9.3%) of the women in the comparison group. The groups were compared with regard to genital signs and symptoms, results of vaginal wet smear microscopy and other office tests, vaginal flora changes as detected by culture, and other means and detection of sexually transmitted diseases. Any history of sexually transmitted diseases and other genital infections, reproductive history, use of oral contraceptives, and smoking habits were registered.

RESULTS

Women who harbored Mycoplasma hominis had significantly more often complained of a fishy odor, had a positive amine test, a vaginal pH > 4.7, and clue cells than did the comparison group; all these statements were true before and after bacterial vaginosis had been excluded. Vaginal discharge was not significantly more often complained of, and a pathologic discharge was not more often detected in the Mycoplasma hominis carriers. Ureaplasma urealyticum occurred in 75% of the Mycoplasma hominis-positive women and in 59% of the comparison group (p = 0.001). The leukocyte/epithelial cell ratio did not differ significantly from that of the Mycoplasma hominis culture-negative controls.

CONCLUSION

The study suggests that Mycoplasma hominis is associated with a number of genital signs and symptoms even after exclusion of bacterial vaginosis.

Genital mycoplasmas in preterm infants: prevalence and clinical significance

The genital mycoplasmas: Ureaplasma urealyticum and Mycoplasma hominis have recently assumed an increasing importance as neonatal pathogens. The aim of the present survey was to determine the prevalence of infections with these organisms in preterm infants in two neonatal intensive care units in Israel. Among 99 preterm infants, 24 (24%) harboured mycoplasmas in their throats shortly after birth. U. urealyticum was the most common organism. M. hominis was isolated only from 3 infants. Six out of 27 (22%) mechanically ventilated infants secreted U. urealyticum in their lower airways. The rate of colonization was inversely correlated with gestational age; 80% of infants younger than 28 weeks gestation were found to be colonized as opposed to 17.9% at 28-36 weeks of gestation. No mycoplasmas were isolated in blood cultures drawn from 146 infants and CSF cultures obtained from 47 preterm infants. Neonatal mortality, respiratory complications and intraventricular haemorrhage grade 3-4 were significantly increased in colonized infants. However, above gestational age of 27 weeks, colonization with mycoplasmas was not associated with a worse prognosis. We conclude that colonization with U. urealyticum is common in Israeli preterm infants, correlates inversely with gestational age and has no detrimental effect on neonatal morbidity and mortality of infants older than 27 wks of gestation.

A study of three blood culture media for isolating genital mycoplasmas from obstetrical and gynaecological patients

Mycoplasma species are often found colonising the female genital tract. Their ability to become invasive and pathogenic, however, is often ignored, since attempts may not be made to culture these organisms from the bloodstream. We have investigated the ability of three types of blood culture media to support the growth of genital mycoplasmas. The media studied included brain-heart infusion broth, brain-heart infusion broth supplemented with 30% V/V sucrose and fastidious anaerobe broth. Genital mycoplasmas were cultured from the latter medium only. Since this was the sole medium which was liquoid-free, the inhibitory effects of liquoid on Mycoplasma spp. is discussed. This study comprised an investigation of 75 patients in obstetric and gynaecological wards with postpartum or post-operative fever. Genital mycoplasmas were isolated from five (6.7%) patients, four with Ureaplasma urealyticum and one with M. hominis. The value of considering these organisms in the differential diagnosis of fever in 'at risk' patients and of including appropriate media for their isolation is emphasised.

Mycoplasma hominis in maternal and fetal infections

Although prevalence of M. hominis colonization during pregnancy varies from 12-50%, its role in infections of the mother and newborn infants is unclear. Definite correlations exist with chorioamnionitis and amniotic fluid infections, but as it is rarely isolated alone during these infections, its pathogenic role is uncertain. Its association with septic abortion is similarly questioned. Prevalence and antibody titers to M. hominis increase with increasing parity. Transient bacteremia occurs in approximately 2.5% of normal deliveries. M. hominis does have a significant role in postpartum fever. Women harboring the organism during labor with low predelivery antibody titers are at risk. Approximately 30% of exposed infants are colonized (4% of all infants) but there are only a few reports of neonatal meningitis, pneumonia, or skin abscesses due to M. hominis. Most recover without specific therapy. The role of antimicrobial therapy of M. hominis in pregnancy and the neonatal period is unclear. Further studies of these issues should simultaneously consider all potential genital tract pathogens.

Fetal body and breathing movements as predictors of intraamniotic infection in preterm premature rupture of membranes

A prospective study of fetal behavior in cases complicated with preterm premature rupture of membranes was conducted in 41 patients. The length of time and the number of fetal breathing and gross body movements were correlated with the amniotic fluid culture results. An episode of fetal activity (body movements and breathing movements) of greater than or equal to 30 seconds during 30 minutes of observation was associated with the absence of intraamniotic infection in 100% of the cases. On the other hand, the absence of fetal breathing movements and gross body movements of less than a 50 second duration during 30 minutes of observation was associated with positive amniotic fluid cultures in all cases. If an episode of fetal breathing movements was present but lasted less than 30 seconds and/or the total time of gross body movements was greater than 50 seconds, 64% of patients had an intraamniotic infection.

Non-occurrence of Mycoplasma genitalium in clinical specimens

Five hundred and thirteen clinical specimens, mainly from patients with urogenital inflammations, were examined for Ureaplasma urealyticum and mycoplasmas, including cultures for Mycoplasma genitalium. The study yielded 95 isolates of Ureaplasma urealyticum, 37 isolates of Mycoplasma hominis and two isolates of Mycoplasma fermentans, but no growth of Mycoplasma genitalium was obtained. It was concluded that Mycoplasma genitalium is a relatively rare inhabitant of the human urogenital tract in Israel.

Clinical and microbiologic risk evaluation for post-cesarean section endometritis by multivariate discriminant analysis: role of intraoperative mycoplasma, aerobes, and anaerobes

The clinical and microbiologic risk factors for postpartum endometritis were studied prospectively in 77 patients undergoing cesarean section without antibiotic prophylaxis at Harbor-University of California at Los Angeles Medical Center. Intraoperative cultures were obtained from the amniotic fluid, lower uterine segment, and abdominal wound for isolation of genital mycoplasmas, aerobes, and anaerobes. Postsection endometritis developed in 21 (27%) patients and was significantly associated with presence of either high-virulence bacteria (predominantly, coliforms, streptococci, anaerobic cocci, and bacteroides) (35% to 60% versus 10% to 24%; p less than 0.05) or Ureaplasma urealyticum (15% to 42% versus 0% to 10%; p less than 0.05) at any site compared with afebrile women. Multivariate analysis identified primary cesarean section, younger maternal age, presence of ruptured membranes, and presence of Ureaplasma as significant risk factors independent of other confounding variables (p less than 0.01). It is suggested that genital mycoplasmas could play a primary role in some cases of postsection endometritis or that they are cofactors or markers for the presence of other high-virulence aerobic and anaerobic bacteria.

Cefotaxime in the treatment of female pelvic soft tissue infections

Forty-six females with pelvic soft tissue infections (recurrent salpingitis [n = 14], salpingitis with intrauterine contraceptive device [IUD] [n = 9], salpingitis with adnexal mass [n = 14], post-partum endomyoparametritis [n = 9]) were randomized for three antibiotic treatment regimens: cefotaxime (CTX) (n = 23), clindamycin and gentamicin (C + Gen) (n = 13), and clindamycin, gentamicin and penicillin (C + Gen + P) (n = 10). Patients were evaluated by diagnosis for clinical response to the three regimens and by pre-treatment bacterial susceptibility to the individual as well as the combination antibiotics. All 14 recurrent salpingitis patients responded satisfactorily to the assigned antibiotic regimen (CTX, n = 8; C + Gen, n = 3; C + Gen + P, n = 3). One of four patients with the diagnosis of salpingitis/IUD treated with CTX was a treatment failure, while three of three patients treated with C + Gen and two of two patients with C + Gen + P responded satisfactorily. Two of three patients with the diagnosis of salpingitis/adnexal mass failed therapy with C + Gen while the seven patients treated with CTX and the four patients with C + Gen + P responded satisfactorily. All nine patients with endomyoparametritis responded to their treatment regimen. Overall, there were no statistically significant differences in the responses by diagnosis and regimen, with the exception that C + Gen was significantly different (p less than 0.05) from CTX and C + Gen + P for the treatment of salpingitis with mass. Of the 141 bacterial isolates in all groups, 57 were aerobic or anaerobic gram-positive organisms.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of media for isolation of Ureaplasma urealyticum and genital Mycoplasma species

A total of 484 frozen patient specimens originally positive for Ureaplasma urealyticum or Mycoplasma spp. or both were recultured, and the results were compared on the following media: Shepard's A7 agar, modified phenol red-urea, SP-4-urea, modified phenol red-arginine, and SP-4-arginine broths. Of 351 specimens positive for U. urealyticum, 30 (8.5%) were detected only in one or more of the broth media, whereas 117 (33%) were positive only on A7 agar. Separate use of the SP-4-urea broth or modified phenol red-urea broth isolated all but 1 and 2, respectively, of the negative A7 agar cultures. Of the 76 specimens positive for large colony Mycoplasma spp., 58 (76.3%) were not grown on the primary plating (A7) agar. Of 73 broth isolates, 73 (100%) grew in SP-4-arginine broth, and 64 (87.7%) grew in modified phenol red-arginine broth. Modified SP-4 broth appears to be a useful supplement to the A7 plating medium commonly used in the diagnostic laboratory for the isolation of U. urealyticum and Mycoplasma spp.

Prevalence of six sexually transmitted disease agents among pregnant inner-city adolescents and pregnancy outcome

115 pregnant girls aged 13-17 years were investigated during the third trimester for endocervical infection with six sexually transmissible microorganisms. Specimens from 21 patients destroyed the tissue cell monolayers for propagation of Chlamydia trachomatis, but 11 were no longer toxic when recultured after freezing or with additional antimicrobial agents; Trichomonas vaginalis was present in 76% of the toxic specimens. C trachomatis was recovered from 37% of 105 specimens. T vaginalis was recovered from 34% of the 115 subjects, candida from 38%, Mycoplasma hominis from 70%, and Ureaplasma urealyticum from 90%. Neisseria gonorrhoeae was cultured from 1 of 12 girls infected earlier in pregnancy. T vaginalis infection, alone or with C trachomatis or candida, was associated with low gestational age and low birthweight. C trachomatis and candida infections alone had no effect on pregnancy outcome.

Detection of Mycoplasma hominis antigen in clinical specimens by using a four-layer modification of enzyme immunoassay (EIA)

A 4-layer modification of enzyme immunoassay (EIA) was developed for the detection of Mycoplasma hominis antigen in clinical specimens. Microtiter plates were sensitized with rabbit anti-mycoplasma immunoglobulin, guinea pig anti-mycoplasma immunoglobulin was used as the secondary antibody, and horseradish peroxidase-conjugated anti-guinea pig immunoglobulin was used as the indicator antibody. The specificity of the assay was confirmed by using guinea pig immunoglobulins from preimmunization sera. The sensitivity of the assay is down to 10 ng/ml of antigen protein. Marked cross-reactivity was demonstrated for different strains within the species M. hominis, whereas the other genital mycoplasma species tested showed no reactivity in the assay. A comparison was made of EIA and conventional culture of vaginal specimens from 24 women. All 6 specimens positive by culture were also positive for M. hominis antigen by EIA. Antigen detection by EIA is a sensitive, rapid and simple method for the detection of M. hominis in clinical specimens.

Lack of association between genital mycoplasmas and infertility

We studied the relation between colonization with Mycoplasma hominis and Ureaplasma urealyticum, and the results of infertility studies in 205 women with involuntary infertility of at least one year's duration. Isolation of M. hominis (but not of U. urealyticum) was significantly (P = 0.002) more common in patients with a history of pelvic inflammatory disease. However, no relation could be shown between these genital mycoplasmas and any of the following: evidence of prior pelvic inflammatory disease as determined by hysterosalpingography and laparoscopy; cervical inflammation; numbers and motility of spermatozoa on postcoital test; pyosemia; quality of cervical mucus; whether the cause of infertility was related to male or female factors, both, or neither; and occurrence and outcome of subsequent pregnancy. Mycoplasmas were cultured from only 10 of 203 endometrial biopsy specimens (4.9 per cent), and in no instance was inflammation associated with this finding. Out studies do not support a role for genital mycoplasmas in the cause of infertility.

Evaluation of PPLO, A7B, E, and NYC agar media for the isolation of Ureaplasma urealyticum and Mycoplasma species from the genital tract

Four agar media (PPLO, NYC, A7B, and E) which are commonly used for the isolation of urogenital tract Mycoplasma species and Ureaplasma urealyticum were compared by culturing swabs of the endocervix of 334 pregnant women on all four media. To permit growth of both Mycoplasma and U. urealyticum, selective ingredients were omitted from the media tested. A7B and E agar were both satisfactory for the isolation of Mycoplasma species, recovering 92 and 82%, respectively, of all Mycoplasma species isolated. Only A7B agar was satisfactory for U. urealyticum isolation, recovering 96% of all isolates. Several modifications of PPLO, NYC, and E agar failed to significantly improve recovery of U. urealyticum on these media. A7B agar was clearly superior to all other media tested in terms of recovery rate, typical appearance of colonies, and ease of reading. A7B can be used for the isolation of both U. urealyticum and Mycoplasma species from urogenital sites.

Genitourinary infection with Ureaplasma urealyticum in women attending a sexually transmitted diseases clinic

Ureaplasma urealyticum was detected in the cervix of 49·9% and in the urine of 47·7% of women attending a department of genitourinary medicine. Isolation of U urealyticum was not related to diagnosis, nor was there any association between the presence of the organism and any symptoms or signs of genital tract disease. Fewer organisms were detected in the cervix of women who had a concurrent infection with Chlamydia trachomatis than in women who had not. A pathological role for U urealyticum has not been established.

Standardized method for determining antimicrobial susceptibility of strains of Ureaplasma urealyticum and their response to tetracycline, erythromycin, and rosaramicin

We describe a method for determining the minimal inhibitory concentrations (MICs) of antibiotics for Ureaplasma urealyticum which is compatible with current standard of susceptibility testing. A presumptive MIC is available after 24 h of incubation, and the definitive MIC is available at 48 h. The MICs for 9 serotype strains and 27 clinical isolates ranged from less than or equal to 0.5 to 256 microgram of tetracycline per ml, greater than or equal to 1 to 64 microgram of erythromycin per ml, and 0.031 to 4.0 microgram of rosaramicin per ml. Of an additional 555 isolates screened for their response to tetracycline, 2% required MICs of greater than 64 microgram/ml, which we believe is near the concentration at which in vivo resistance to this agent is expressed. After prolonged exposure to rosaramicin, the resistance of two of three serotype strains of U. urealyticum was increased 8- and 16-fold, but the MICs still did not exceed 1.0 microgram/ml.

Sexually transmitted conditions among women college students

We studied 500 unselected young women who consulted a gynecologist in a student health service. Most participants were symptom-free and had normal physical examinations. Few sexually transmitted infections were encountered. Neisseria gonorrhoeae was recovered from two and Trichomonas vaginalis was obtained from 14 of 500 women. Chlamydia trachomatis was recovered from 20 (4.6%) of 439 participants. Genital warts, genital herpes, and molluscum contagiosum, respectively, were noted in seven, four, and one of the 500 participants. There was no cases of syphilis, scabies, or pediculosis pubis. Mycoplasma hominis and Ureaplasma urealyticum, respectively, were recovered from 17.6 and 56.8% of the subjects. Prevalent vaginal bacteria included lactobacilli, streptococci, Staphylococcus epidermidis, and diphtheroids. Gardnerella vaginalis was isolated from the vaginal specimens of about one third of the participants.

Infection with Mycoplasma hominis in postpartum fever

A follow-up of 535 patients after vaginal delivery showed that 9% had a fever of 37.7 degrees C or greater, and 2% had a fever of 38 degrees C or more, on two days. The commonest cause of both categories of fever was Mycoplasma hominis infection as defined by a fourfold or greater rise in mycoplasmacidal antibody titre. Among women for whom sera were available this agent caused 50% (14/28) of all fevers and 71% (5/7) of the higher fevers. Absence or low titre (< 1:8) of antibody against M. hominis was the strongest single predictor of otherwise unexplained fever (16/40 patients with low antibody titre were febrile vs 7/50 with high antibody titre, p < 0.01). Among women with absent or low antibody titres, both rise in titre of antibody to this organism and lochial colonisation by it were significantly associated with fever (p < 0.001, p < 0.025, respectively). Standard microbiological and clinical techniques identified probable causes in only 18% (5/28) of all fevers and 29% (2/7) of higher fevers. Patients who had postpartum infection caused by M. hominis remained in hospital 31% longer than the non-infected patients (4.57 vs 3.49 days, p < 0.001). Low antibody to and lochial colonisation with M. hominis occurred together in 17% of patients, who accounted for 71% of all higher fevers. Since these risk factors for postpartum fever can be identified before delivery, prophylactic measures applied selectively to women with these risk factors may prevent a large proportion of postpartum fevers and the excess hospital stay associated with them.

Fourteen serotypes of ureaplasma urealyticum (T-mycoplasmas) demonstrated by the complement-dependent mycoplasmacidal test

Previously, we found that strains of Ureaplasma urealyticum could be divided into 11 serotypes using the mycoplasmacidal (MC) method for serotyping. Subsequent study has shown that two pairs of these strains were sufficiently closely related to cause us to revise the typing scheme into nine distinct serotypes. Other investigators, using different methods to detect serotypic diversity, have found eight serotypes. We have now compared our nine strains with the eight prototype strains developed by Ford and Black, and we have used reciprocal MC titers of antisera for the comparison. Three pairs of strains from our group and the group prepared by Ford and Black were found to be serologically closely related or identical, leaving six serotypes in our series and five in the other series that were serologically unique. Thus 14 serotypes of U. urealyticum have been identified in these studies, and a 15th strain that is apparently serologically distinct from the others, has recently been described in Vancouver.

Mycoplasma infection and infertility

Attempts were made to isolate mycoplasmas from the uterine cervix of infertile women and normal pregnant and nonpregnant women to investigate the relationship of genital mycoplasma infection to infertility. Ureaplasma urealyticum was demonstrated in 63% of patients with infertility, 68% of normal pregnant women, and 62% of normal nonpregnant women. The incidence of Mycoplasma hominis infection was found to be noticeably lower, with corresponding isolation rates of 10%, 11%, and 6%, respectively. The differences in rate of isolation for U. urealyticum and for M. hominis among the three groups did not reach statistical significance. During a follow-up period of more than 12 months without any treatment for mycoplasma infection in the infertile cases, 11 women (27.5%) became pregnant. These included 7 (28%) of 25 women with positive U. urealyticum cultures. The results demonstrate a fairly high incidence of female genital infection with U. urealyticum which, as the data would indicate, cannot be directly associated with infertility.

Genital mycoplasmas and birth weight in offspring of primigravid women

The relationship between colonization of pregnant women by Ureaplasma and Mycoplasma and the outcome of pregnancy in a study of 104 women is reported. There were eight abortions but no multiple births or stillbirths. Excluding abortions, the mean gestational length was 39.6 weeks and the corrected mean birth weight was 3.28 kilograms. There was no relationship between maternal colonization by genital mycoplasmas and reduction in birth weight of the offspring, but five of the eight women who aborted harbored Ureaplasma, suggesting an increased trend toward abortion in women harboring Ureaplasma.

Genital mycoplasma infections

Three different species of mycoplasmas--M. hominis, M. fermentans, and Ureaplasma urealyticum--have been found to infect human genitalia. In the man, mycoplasmas appear to play a role in the etiology of nonspecific urethritis and prostatis. Mycoplasmas repeatedly have been cultured from the tubes of patients with acute salpingitis and a significant antibody response to the organisms during recovery has been reported. Obstetric infections and puerperal sepsis occasionally seem to be caused by mycoplasmas. These organisms also appear to induce spontaneous abortion as well as cause infertility in a small proportion of couples.

Microbiological investigation of Bartholin's gland abscesses and cysts

Percutaneous aspirates from intact Bartholin's gland cysts (12) and abscesses (34) were examined for bacteria and genital mycoplasmas. Aspirates from 10 of the 12 patients with Bartholin's gland cysts were sterile. Aspirates from the other two cysts contained organisms that are part of the vaginal microbial flora. Of the 34 abscesses, 24 (70.6 per cent) contained bacteria. Eight abscesses contained gram-negative rods in pure culture and four contained gonococci in pure culture. Twelve abscesses contained one or more vaginal organisms including anaerobic gram-negative rods (eight isolates), anaerobic gram-positive cocci (eight), Staphylococcus epidermidis (four), and microaerophilic streptococci (three). Although most of the patients had genital mycoplasmas isolated from vaginal cultures, Mycoplasma hominis was isolated from only one and Ureaplasma urealyticum from none of the aspirates.

Puerperal infection in the antibiotic era

Developments in etiology and treatment of puerperal infection in the last 20 years are reviewed. Emphasis is placed upon predisposing factors, microbiology and antibiotics, unusual sources of severe infection, special complications, and prophylactic antibiotics.

Prevalence of Mycoplasma hominis and Ureaplasma urealyticum (T strains) in urine of adolescents

Adolescent children were surveyed for colonization with Mycoplasma hominis and Ureaplasma urealyticum by culturing urine specimens. Rates were compared between three study groups: (i) 397 children attending parochial schools, (ii) 293 children attending an adolescent clinic specializing in adjustment problems, and (iii) 86 children attending a renal clinic. The recovery rate was higher among postpubertal girls attending the renal clinic (33%) and the adolescent clinic (26%) than among students attending parochial high school (males 2%, females 8%). Girls had approximately eightfold higher rates than boys of the same age. Isolation of Mycoplasmataceae was associated with certain sociological determinants, such as dating, cigarette smoking, and coming from a broken home, but also with abnormal findings (protein, leucocytes) in urine.

Chorioamnionitis and colonization of the newborn infant with genital mycoplasmas

To study the role of Mycoplasma hominis and T-mycoplasmas (Ureaplasma urealyticum) in chorioamnionitis, we obtained culture from 249 puerperal women and their babies. The placentas were examined histologically. Infants whose placentas showed inflammation (chorioamnionitis) had cultures positive for T-mycoplasmas more frequently (37.5 per cent) than those with normal placentas (19.0 per cent) (P = 0.021). Colonization with M. hominis was found in 16.0 per cent of the babies and was not significantly associated with chorioamnionitis. Material colonization with mycoplasmas was more frequent (73.4 per cent) and was not correlated with placental inflammation. We conclude that a substantial proportion of cases of chorioamnionitis may be caused by prenatal infection with T-mycoplasmas. The fact that these organisms are not highly virulent could explain the frequent finding of inflammed placentas from otherwise normal pregnacies. No adverse clinical effects of the placental lesions or of mycoplasmal colonization could be detected in this small study.

Isolation of genital mycoplasmas from blood obtained shortly after vaginal delivery

Blood obtained from three hundred and twenty-seven women within a few minutes of vaginal delivery was cultured for genital mycoplasmas (Mycoplasma hominis and T mycoplasmas). Twenty-six (8%) of the women had genital mycoplasmas isolated from their blood. Ten women had blood-cultures which contained M. hominis. Fifteen women had blood-cultures which contained T mycoplasmas. Both M. hominis and T mycoplasmas were isolated from the blood of one woman. Only one of two hundred and seventy-three blood-cultures obtained 1 or more days after delivery contained mycoplasmas. The isolation of M. hominis, but not of T mycoplasmas, from the blood was associated with vaginal colonisation and a serological response to the homologous isolate. Two of ten women whose blood contained M. hominis gave birth to stillborn infants. In contrast, there were only four (1.3%) stillbirths among the infants born to the three hundred and one women whose blood did not contain mycoplasmas. This difference is statistically significant.

Doxycycline treatment and human infertility

The role of mycoplasmas in infertility was studied in 120 couples. During the twelve months of the study 27 couples (22-5%) conceived. T mycoplasmas were isolated from 63% of these couples, and Mycoplasma hominis from 18%, compared with 56% and 13%, respectively, in those who did not conceive. 88, with primary infertility of unascertained cause, took part in a controlled trial with doxycycline. The couples in the trial were allocated randomly to three groups: 30 received doxycycline, 28 received a placebo, and 30 couples were untreated. Although a twenty-eight-day course of doxycycline eradicated M. hominis and T-strain mycoplasmas from 27 (96%) of the 28 couples harbouring them, the rate of conception was no higher in those treated with the drug than in control groups. It is concluded that mycoplasmas are not associated with primary infertility and that, although doxycycline eradicates them, this drug is of no benefit in the treatment of primary infertility of unascertained cause.

Prolonged stationary-phase growth of T-strain mycoplasmas in broth culture

Growth of T-strain mycoplasmas in standard broth cultures has been characterized by rapid growth to peak titers of 10(6) to 10(7) color change units/ml at 20 to 24 hr, followed by a sharp decline in the viability over the next few hours. In a vacuum-flow (V-F) system utilizing negative pressure equal to 10 cm of water and air flow on the surface of broth, T strains were seen to enter the stationary phase of growth after 24 hr, and viability titers after 72 hr were >/= 10(4) color change units/ml. Maintenance of organisms in the stationary phase required both vacuum and air flow, a medium depth of 1 mm, and 1% urea in the broth. Concentration of ammonia in broth cultures under V-F remained below 200 mug/ml during 72 hr of observation. Ammonia levels in standard broth cultures exceeded 200 mug/ml after 24 hr, coincident with the decline in viability. Air passed over the medium surface in the V-F system contained large amounts of ammonia; the amount increased during each succeeding 24-hr period of observation.