Significance of appropriate techniques and media for isolation and identification of Ureaplasma urealyticum from clinical specimens

Submicron Particle and Cell Concentration in a Closed Chamber Surface Acoustic Wave Microcentrifuge

Preconcentrating particulate and cellular matter for their isolation or detection is often a necessary and critical sample preparation or purification step in many lab-on-a-chip diagnostic devices. While surface acoustic wave (SAW) microcentrifugation has been demonstrated as a powerful means to drive efficient particle concentration, this has primarily been limited to micron dimension particles. When the particle size is around 1 μm or below, studies on SAW microcentrifugation to date have shown that particle ring-like aggregates can only be obtained in contrast to the localized concentrated clusters that are obtained with larger particles. Considering the importance of submicron particles and bioparticles that are common in many real-world samples, we elucidate why previous studies have not been able to achieve the concentration of these smaller particles to completion, and we present a practical solution involving a novel closed chamber configuration that minimizes sample heating and eliminates evaporation to show that it is indeed possible to drive submicron particle and cell concentration down to 200 nm diameters with SAW microcentrifugation over longer durations.

Genital mycoplasmas in placental infections

Objective: The involvement of the genital mycoplasmas Ureaplasma urealyticum and Mycoplasma hominis in complications of pregnancy has remained controversial especially because these microorganisms are frequent colonizers of the lower genital tract. Recovery of bacteria from the placenta appears to be the sole technique to represent a true infection and not vaginal contamination. Therefore, we investigated the presence of genital mycoplasmas, aerobic and anaerobic bacteria, and fungi in human placentas and evaluated their association with morbidity and mortality of pregnancy.

Methods: We cultured placentas from 82 women with complicated pregnancies. One hundred placentas from women with uncomplicated pregnancies were evaluated as controls. When possible, placentas were examined histologically for presence of chorioamnionitis.

Results: Microorganisms were recovered from 52% of the placentas of complicated pregnancies and U. urealyticum was the microorganism isolated most frequently from the placenta. A significant association between positive mycoplasma culture of the placenta and complication of pregnancy was found, and chorioamnionitis was positively related to isolation of mycoplasmas.

Conclusions: These data suggest that genital mycoplasmas are able to infect the human placenta where they can cause chorioamnionitis. This infection of the placenta by genital mycoplasmas is related to preterm birth and fatal outcome of pregnancy.

Isolation of Mycoplasma species and Ureaplasma urealyticum from obstetrical and gynecological patients by using commercially available medium formulations

One hundred duplicate endocervical specimens from obstetrical and gynecological patients were cultured for Mycoplasma spp. and Ureaplasma urealyticum. Rates of recovery of these organisms from commercially prepared A7 medium and the Mycotrim-GU system were compared. We detected 14 (93%) of the total 15 isolates of Mycoplasma spp. on A7 plates and 11 (73%) in the Mycotrim-GU system. We detected 34 (89%) of the total 38 isolates of U. urealyticum on A7 plates and 32 (84%) in the Mycotrim-GU system. The times of detection for both types of organism were similar in the two systems. We conclude that cultivation on A7 medium as described is a more cost-effective method of recovery of Mycoplasma spp. and U. urealyticum than the Mycotrim-GU system.

Screening for Ureaplasma urealyticum infections in the neonate and the association with prematurity

Ureaplasma urealyticum has been implicated in gynaecological, obstetrical and neonatal pathology. Increased levels of C-reactive protein and total IgM concentrations in cord blood have often been used as a screening method for infectious disease in the fetus and the newborn. Analysis of the isolation rate of U. urealyticum in function of the concentrations of these two parameters in cord blood showed that U. urealyticum was significantly (P less than 0.05) more frequently isolated when CRP was above normal in cord blood. No correlation between the IgM level in the newborn and the presence of U. urealyticum could be established. A significant relationship was found (P less than 0.01) between Ureaplasma isolation in the urine of mother and child on the one hand and gestational age on the other hand, which supports the hypothesis that U. urealyticum may play a role in preterm delivery.

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.

Ureaplasma urealyticum: subcultures invalid for antibiotic susceptibility tests

We tested the antibiotic susceptibilities of 100 Ureaplasma urealyticum strains from 99 patients using a broth-disk method and two types of inocula: urine sediments and overnight broth subcultures of the sediments. Of the 100 ureaplasma-positive urine sediments tested, nine (9%) of the ureaplasmas were found resistant to all four tetracyclines. When overnight broth cultures were used as the inoculum, 54 (54%) were found to be resistant to all four tetracyclines, an increase in resistance of 45 (45%). Thirty-seven susceptible strains remained susceptible upon subculture. The nine resistant strains remained resistant. Loss of susceptibility was not related to the pH or titer of ureaplasmas in the urine sediment inoculum but was related to the pH and titers when subcultures were used as the inoculum. Results of cultures following treatment, available for 53 patients, showed that treatment successes and treatment failures were significantly related to antibiotic susceptibility tests done with urine sediments but not to those done with broth subcultures as the inocula. Because reliable susceptibility testing is essential for appropriate therapy for U. urealyticum infections, all factors influencing this test need to be recognized and defined.

Correlation of postcoital evaluation with in vitro sperm cervical mucus determinations and ureaplasma cultures

Fifteen trials were completed in 14 couples during an infertility evaluation. The postcoital test (PCT) was accomplished in a standardized manner. Also, standardized determinations of the sperm-cervical mucus penetration test (SCMPT) with the addition of cross-testing (X-test) utilizing bovine cervical mucus (BCM) and normal donor semen (NDS) were done. Male and female samples were also cultured for Ureaplasma urealyticum using U9-B indicator broth and A-7 agar. The PCT and SCMPT agreed in 87% (13/15) of the cases. Utilizing BCM and NDS, where possible, the causative factor was the cervical mucus in 54% (7/13); semen factor in 15% (2/13); both factors in 8% (1/13); and undetermined in 23% (3/13). U. urealyticum cultures were positive in 40% (6/15) of the cases. Analysis of the results revealed: (1) significant correlation between PCT and SCMPT (P less than 0.01); (2) no significant difference among the PCT, SCMPT, and X-test, indicating that the cervical mucus was the causative factor; and (3) no U. urealyticum correlation with the PCT or the SCMPT. Thus, laboratory SCMPT and X-test correlated with the PCT, providing additional information concerning the causative factor in infertility. The U. urealyticum status in cervical mucus and semen cannot be determined from the PCT nor the SCMPT.

Nonspecific urethritis in men

The epidemiology, diagnostic criteria, and etiology of nonspecific urethritis in men are discussed. Microbiological examinations have indicated that in the vast majority of these patients Chlamydia trachomatis and Ureaplasma urealyticum are the main causes for the disease. Treatment of the disorder has centered on the use of tetracyclinelike drugs, and with proper treatment cure can be obtained in the majority of patients.

Association of Ureaplasma urealyticum in the placenta with perinatal morbidity and mortality

We investigated the presence of ureaplasmas, mycoplasmas, chlamydiae, fungi, aerobic and anaerobic bacteria, and cytomegalovirus in fetal membranes and evaluated their association with perinatal morbidity and mortality. We cultured 801 placentas from three groups of subjects (144 who died in the perinatal period, 452 neonates admitted to the intensive-care unit, and 205 controls). Ureaplasma urealyticum, Mycoplasma hominis, or both were isolated from 21 per cent of placentas of premature and term infants who died in the perinatal period, 25 per cent of those admitted to intensive care, and 11 per cent of controls. Gestational age and birth weight were inversely related to isolation of ureaplasma, and chorioamnionitis was positively related to isolation. The presence of ureaplasmas in the placenta suggests the transcervical migration of these microorganisms from the lower genitourinary tract. These data show a strong association between ureaplasma infection of the placenta and low birth weight of the neonate and suggest that the association is causal.

Urine as a specimen for diagnosis of sexually transmitted diseases

The case of specimen collection has led to the suggestion that urine might be a useful specimen for the isolation of sexually transmitted disease agents. It would only be an appropriate specimen for agents that infect the urethra, such as Neisseria gonorrhoeae or Chlamydia trachomatis. Comparative tests have shown that culture of urine for chlamydiae (from men with urethritis) or for gonococci from women is an insensitive procedure. Gonococci can be isolated from urine from men at rates essentially equivalent to culture of urethral swabs. If specimens can be processed promptly (to avoid bactericidal effects of urine), culture of urine can likely be useful for screening asymptomatic men for gonococcal infection.

Comparative evaluation of media for isolation of ureaplasma urealyticum and genital mycoplasma species

Two media systems were compared for isolation of Ureaplasma urealyticum and genital Mycoplasma sp. System 1 (S-1) consisted of arginine agar and an arginine biphasic medium for isolation of Mycoplasma sp. and urea agar and urea broth for isolation of U. urealyticum. System 2 (S-2) utilized Boston broth, which is a urea-containing broth, and A7 agar, both of which support the growth of both species. Urine samples, some freshly collected and some known-positive frozen samples, were used as inocula for the two media systems. With S-1, U. urealyticum was recovered in 68% of U. urealyticum-positive cultures: 58% were detected in urea broth, and 60% were identified on urea agar. When the S-2 system was used for culture of the same samples. U. urealyticum was recovered in 98% of the cultures, with 94% detected in Boston broth and 92% identified on A7 agar. Mycoplasma sp. was recovered in S-1 and S-2 in 97 and 100% of Mycoplasma sp.-positive cultures, respectively. The S-1 arginine broth gave positive results for 89% of the cultures, and the arginine agar was positive for 97% of the cultures. The S-2 Boston broth and A7 agar gave positive results for 92 and 97% of the cultures, respectively. For the isolation of U. urealyticum, colony counts were higher, growth was seen sooner, and colonies were larger when the S-2 media system was used. Overall, the cost per test of the S-2 system was less both in technologist time and in reagent costs.

Effect of gaseous conditions on isolation and growth of Ureaplasma urealyticum on agar

Five laboratory-adapted strains of Ureaplasma urealyticum showed comparable colony counts when incubated in eight gaseous environments including air, in different concentrations of carbon dioxide, and under anaerobiosis. For primary isolation on genital mycoplasma agar 95% N2-5% CO2 gave 100% correlation with growth in bromothymol blue broth, whereas certain strains failed to grow on agar incubated in air, the TABCO2 system (Lab-Tek Division, Miles Laboratories, Ltd., Rexdale, Canada), 100% CO2, or under anaerobiosis.

Ureaplasma urealyticum incriminated in perinatal morbidity and mortality

Perinatal morbidity and mortality are associated with colonization of the chorionic surface of the placenta by Ureaplasma urealyticum or Mycoplasma hominis or both. These organisms are more strongly associated with unfavourable gestational outcome than group B streptococci. Chlamydia trachomatis does not appear to be important in the etiology of reproductive casualties. The mechanisms linking the mycoplasmas to perinatal disorders and death are not clear but merit investigation.

Antimicrobial susceptibility of Ureaplasma urealyticum

An antimicrobial susceptibility test, a tow-tube broth dilution and disk elution method for Ureaplasma urealyticum, was modified to incorporate some of the standard procedures followed in traditional antimicrobial testing. The susceptibility pattern of the species was reevaluated by determining the effect of various antimicrobial agents on 21 vaginal isolates. All isolates were inhibited by tetracycline congeners (1 to 6 micrograms/ml) and killed by methenamine mandelate (0.6 mg/ml). All but one isolates were inhibited by erythromycin (0.4 to 3 micrograms/ml). Only eight isolates were inhibited by nalidixic acid (1 to 6 micrograms/ml), and seven were inhibited by nitrofurantoin (20 to 60 micrograms/ml), whereas all isolates were resistant to rifampin (1 microgram/ml) and trimethoprim-sulfamethoxazole (5 micrograms/ml). The in vitro technique described can readily be performed on individual patient isolates before the initiation of antimicrobial therapy.

Survival of Ureaplasma urealyticum on different kinds of swabs

The survival of Ureaplasma urealyticum on five different types of swabs routinely used for obtaining clinical specimens is limited to 1 h. Wooden applicator sticks inhibit the alkaline color change in broth and result in a significant loss of isolates if broth alone is used.