Transposition of gram-positive transposon Tn916 in Acholeplasma laidlawii and Mycoplasma pulmonis.

Mycoplasma genetics has been limited by a lack of genetic tools such as selectable markers, methods to transfer DNA, and suitable vectors for cloning. Studies were undertaken to examine the potential of using the streptococcal transposon Tn916 as a mycoplasma genetic tool. The Escherichia coli plasmid pAM120, which contains Tn916, was transformed into Acholeplasma laidlawii and Mycoplasma pulmonis. Transposition of Tn916 into the mycoplasma chromosome apparently occurred by an excision-insertion mechanism. This example shows that newly introduced DNA from other bacteria can be successfully expressed in mycoplasma and that Tn916 should serve as a powerful genetic tool for the study of mycoplasmas.

Ureaplasmal pneumonia and sepsis associated with persistent pulmonary hypertension of the newborn.

Ureaplasma urealyticum was isolated from the lower respiratory tract of three infants with persistent pulmonary hypertension of the newborn. In one, cultures positive for U urealyticum were obtained on multiple occasions from trachea, blood, and pleural fluid prior to the infant's death on postnatal day 6. Autopsy findings confirmed the presence of severe pneumonia and the organism was again recovered from multiple sites. A second infant had no apparent predisposing factors for development of persistent pulmonary hypertension of the newborn but U urealyticum and Staphylococcus epidermidis were recovered from the trachea antemortem and from lung tissue obtained during autopsy on the 12th postnatal day. The third infant had persistent pulmonary hypertension of the newborn and a pulmonary infiltrate within hours after birth with tracheal cultures positive for both U urealyticum and Mycoplasma hominis. Erythromycin was given for ten days, and the infant gradually improved. Prolonged ventilation with supplemental oxygen was necessary, and chronic lung disease developed. This is the first report of neonatal ureaplasmal pneumonia with sepsis and persistent pulmonary hypertension of the newborn as well as the first time a microorganism other than streptococci has been specifically implicated in the pathogenesis of persistent pulmonary hypertension of the newborn. Respiratory infections with U urealyticum or other bacteria should be considered as possible causative or contributory factors in infants with persistent pulmonary hypertension of the newborn.

Association of genital mycoplasmas with exudative vaginitis in a 10 year old: a case of misdiagnosis.

A 10-year-old girl with a 1-year history of lower genitourinary tract symptoms suggestive of bacterial infection but with numerous negative urine cultures was referred to the University of Alabama urology clinic after empirical treatment with multiple antibiotics failed to resolve her symptoms. An extensive urologic evaluation revealed no structural or physiologic abnormalities, but an exudative vaginitis was noted and large numbers of Ureaplasma urealyticum and Mycoplasma hominis were isolated from the lower genital tract. Cultures for Chlamydia, viruses, and routine bacterial pathogens were negative. After initiation of tetracycline therapy, symptoms resolved and subsequent cultures for mycoplasmas were negative. In addition, a seroconversion was noted for M hominis but not for U urealyticum. Chlamydia serology was negative. It was later learned that the patient had been sexually molested just prior to the onset of symptoms. This case illustrates the necessity of early consideration of a mycoplasmal etiology in the patient with persistent genitourinary symptoms and no obvious bacterial pathogen, or in the patient whose condition is refractory to routine antibiotic therapy.

Infant pneumonitis associated with cytomegalovirus, Chlamydia, Pneumocystis, and Ureaplasma: a prospective study.

In a prospective study of 104 infants between 1 and 3 months of age hospitalized with pneumonitis, 65 (63%) had evidence of infection with one or more potential respiratory pathogens. Single infections were noted in 48 (74%) whereas mixed infections occurred in 17 (26%) of 65 infected infants. The four most common infections were Chlamydia trachomatis (15/59, 25%), Ureaplasma urealyticum (8/38, 21%), cytomegalovirus (21/104, 20%), and Pneumocystis carinii (19/104, 18%). In sharp contrast, the incidence of these infections in control infants was 0% (0/25), 4% (2/49), 3% (3/97), and 0% (0/64), respectively. The clinical, radiologic, and laboratory characteristics of the pneumonitis syndrome associated with Chlamydia, cytomegalovirus, and Pneumocystis were indistinguishable from each other. Patients with mixed infections had a more severe pneumonitis as measured by the occurrence of apnea and the need of oxygen therapy an mechanical ventilation. The patients enrolled in this study are being followed-up to determine the longitudinal course of these infections.

Antibiotic susceptibilities and therapeutic options for Ureaplasma urealyticum infections in neonates.

The appreciation of Ureaplasma urealyticum as a human pathogen and documentation of antibiotic resistance have heightened interest in drug susceptibilities and treatment alternatives for patients infected with this organism. Neonates pose special problems when therapy must be considered because of potential toxicities, clinical unfamiliarity or lack of experience. Forty-three isolates of U. urealyticum obtained from the lower respiratory tracts of neonates were tested against chloramphenicol, ciprofloxacin, clindamycin, erythromycin, doxycycline, and gentamicin by a microbroth dilution technique in 10B broth. In vitro resistance was observed in 1 or more strains for each of the drugs tested, except for erythromycin (minimal inhibitory concentration (MIC) range, 0.125 to 4 micrograms/ml, MIC90 = 2 micrograms/ml). MIC90 values for the remaining five antibiotics were: doxycycline, 2 micrograms/ml; chloramphenicol, 8 micrograms/ml; ciprofloxacin, 8 micrograms/ml; clindamycin, 16 micrograms/ml; and gentamicin, 32 micrograms/ml. The effect of pH and/or media components on MICs was evaluated by comparing MICs of American Type Culture Collection reference strain Staphylococcus aureus 29213 obtained in Mueller-Hinton broth (pH 7.2 to 7.4) and 10B broth (pH 6.0). No appreciable effect was detected for ciprofloxacin, chloramphenicol or doxycycline, whereas gentamicin, erythromycin and clindamycin all had MICs elevated by one to several dilutions when tested in 10B broth. In some instances the difference was sufficient to alter the interpretation of the MIC. Clinical experience in treating neonatal ureaplasmal infections is reviewed along with recommendations for obtaining cultures, initiating and monitoring efficacy of therapy.

Neonatal serologic response at term to the genital mycoplasmas.

Genital mycoplasmas are frequently found in the amniotic fluid (AF) of women with ruptured membranes but are infrequent pathogens in the neonates born to these women. The serologic response to the genital mycoplasmas, Mycoplasma hominis and Ureaplasma urealyticum, was studied in 35 mother-baby pairs following term deliveries. Amniotic fluid and neonatal surface cultures were obtained in all cases, as were maternal and neonatal acute and convalescent sera. Despite significant maternal serologic response, there was essentially no neonatal response. Mothers with M. hominis in the AF were significantly more likely than those with negative cultures for M. hominis to exhibit IgG seroconversion and had significantly greater changes in IgG concentrations. Their infants, however, did not exhibit a significant seroresponse regardless of the AF and neonatal culture results. There was also a significant maternal seroresponse to U. urealyticum. However, this did not correlate with the presence of U. urealyticum in the AF. Significantly fewer neonates exhibited a seroresponse to U. urealyticum, again with no relation to culture results.

Mycoplasma pneumoniae and Chlamydia pneumoniae in pediatric community-acquired pneumonia: comparative efficacy and safety of clarithromycin vs. erythromycin ethylsuccinate.

We evaluated 260 previously healthy children ages 3 through 12 years who had clinical signs and symptoms of pneumonia, radiographically confirmed. Patients were randomized 1:1 to a 10-day course of either clarithromycin suspension 15 mg/kg/day divided twice a day or erythromycin suspension 40 mg/kg/day divided twice a day or three times a day. Evidence of infection with Chlamydia pneumoniae was detected in 28% (74) of patients: 13% (34) by nasopharyngeal culture and 18% (48) by serology with the microimmunofluorescence assay. Evidence of infection with Mycoplasma pneumoniae was detected in 27% (69) of patients: 20% (53) by nasopharyngeal culture or polymerase chain reaction and 17% (44) by serology with the use of enzyme-linked immunosorbent assay. Serologic confirmation of infection was observed in 23% (8) and 53% (28) of patients with bacteriologically detected C. pneumoniae and M. pneumoniae, respectively. Treatment with clarithromycin vs. erythromycin, respectively, yielded the following outcomes: clinical success 98% (121 of 124) vs. 95% (105 of 110); radiologic success 98% (109 of 111) vs. 94% (92 of 110); and eradication by pathogen, C. pneumoniae 79% (15 of 19) vs. 86% (12 of 14) and M. pneumoniae 100% (9 of 9) vs. 100% (4 of 4). Adverse events were primarily gastrointestinal occurring in almost one-fourth of patients in both groups, and were mild to moderate in severity. Clarithromycin and erythromycin were similarly effective and safe for the treatment of radiographically proved, community-acquired pneumonia in children older than 2 years old.(ABSTRACT TRUNCATED AT 250 WORDS)

Safety and efficacy of azithromycin in the treatment of community-acquired pneumonia in children.

OBJECTIVE: To compare the safety and efficacy of azithromycin with amoxicillin/clavulanate or erythromycin for the treatment of community-acquired pneumonia, including atypical pneumonia caused by Mycoplasma pneumoniae and Chlamydia pneumoniae. METHODS: Multicenter, parallel group, double blind trial in which patients 6 months to 16 years of age with community-acquired pneumonia were randomized 2:1 to receive either azithromycin for 5 days or conventional therapy for 10 days (amoxicillin/clavulanate if < or =5 years of age or erythromycin estolate if >5 years of age). Patients from 23 geographically diverse sites were evaluated for clinical outcomes and/or adverse events at Days 3 to 5, Days 15 to 19 and 4 to 6 weeks posttherapy. Microbiology (culture or polymerase chain reaction) was done at baseline and Days 15 to 19 for bacteria, Chlamydia pneumoniae and Mycoplasma pneumoniae. Serology for C. pneumoniae and M. pneumoniae was done at baseline and 4 to 6 weeks posttherapy. RESULTS: Of 456 patients enrolled during 17 consecutive months, 420 were evaluable. Clinical success at Study Days 15 to 19 was 94.6% in the azithromycin group and 96.2% in the comparative treatment group (P = 0.735) and at 4 to 6 weeks posttherapy 90.6 and 87.1%, respectively (P = 0.330). Evidence of infection was identified in 46% of 420 evaluable patients (1.9% bacteria, 29.5% M. pneumoniae and 15% C. pneumoniae). Microbiologic eradication was 81% for C. pneumoniae and 100% for M. pneumoniae in the azithromycin group vs. 100 and 57%, respectively, in the comparator group. Treatment-related adverse events occurred in 11.3% of the azithromycin group and 31% in the comparator group (P < 0.05). CONCLUSION: Azithromycin used once daily for 5 days produced a satisfactory therapeutic outcome similar to those of amoxicillin/clavulanate or erythromycin given three times a day for 10 days for treatment of community-acquired pneumonia. Azithromycin had significantly fewer side effects than comparator drugs.

Role of Ureaplasma urealyticum and other pathogens in the development of chronic lung disease of prematurity.

A prospective cohort study enrolling 107 infants weighing less than 1250 g was conducted between September 1, 1986, and November 15, 1987 in order to determine the role of microorganisms on the development of chronic lung disease (CLD). Ureaplasma urealyticum was isolated significantly more frequently from gastric aspirates and nasopharyngeal or endotracheal aspirates from 43 infants developing CLD than from 56 who did not (51% vs. 16%; P less than 0.005). Infants developing CLD, defined by radiographic and blood gas abnormalities, were significantly younger (26 vs. 29 weeks; P less than 0.0001), weighed significantly less (830 vs. 1050 g; P less than 0.0001) and required more ventilatory support (37 vs. 10 were being ventilated and 42 vs. 26 received oxygen supplementation on Day 7) compared with those who did not develop CLD. Viruses were isolated in association with U. urealyticum in two infants developing CLD and in one infant who did not develop CLD. Mycoplasma hominis was isolated from three infants who were colonized with U. urealyticum and developed CLD. Chlamydia trachomatis was not recovered from any patients. From a discriminant analysis it was found that U. urealyticum contributed to the development of CLD along with the effect of ventilatory support, gestational age and severity of initial respiratory disease. The effect of interventions directed against U. urealyticum on the development of CLD deserves further study.

Mycoplasmal infections of cerebrospinal fluid in newborn infants from a community hospital population.

Mycoplasma hominis or Ureaplasma urealyticum have previously been isolated from cerebrospinal fluid (CSF) in 13 of 100 newborn infants tested from a high risk university hospital population where the mothers were of predominantly lower income and socioeconomic status and had often received little or no prenatal care. We sought to determine whether such infections occur in neonates born to women cared for mainly through private obstetric practices and who delivered in 4 suburban community hospitals. CSF cultures were done in 318 infants during an 8-month period. M. hominis was isolated from 9 and U. urealyticum from 5 CSF cultures. Four infants infected with U. urealyticum and 3 infected with M. hominis were born at term. One infant infected with U. urealyticum had a birth weight of less than 1000 g. In 5 infants clearance of the infecting organism was documented without specific treatment. Twelve infants had good perinatal outcomes regardless of treatment and 2 died. One death in a 2240-g infant infected with M. hominis was associated with Haemophilus influenzae sepsis and pneumonia. The other death occurred 3 days after birth in a 630-g infant infected with U. urealyticum who had evidence of meningitis and intraventricular hemorrhage. Results of this study suggest that mycoplasmas are common causes of neonatal CSF infections, not only in high risk populations, but also in the general population.

Serum concentrations of erythromycin after intravenous infusion in preterm neonates treated for Ureaplasma urealyticum infection.

Erythromycin is receiving renewed attention as an alternative for treatment of neonatal infections caused by Ureaplasma urealyticum because of recently proved abilities of this organism to produce systemic disease in this population. Although erythromycin has been used clinically for almost 40 years, very little is known about its activity in the preterm neonate. Fourteen neonates, birth weights < or = 1500 g and < or = 15 days of age, from whom U. urealyticum was isolated from the lower respiratory tract were randomized to receive erythromycin lactobionate either 25 or 40 mg/kg/day in four divided doses at 6-hour intervals scheduled for a total of 10 days. Blood samples collected at multiple time points after initial and steady state doses were assayed for erythromycin by liquid chromatography. Minimal inhibitory concentrations (MICs) of erythromycin for the U. urealyticum isolates were determined. MICs ranged from 0.031 to 2 micrograms/ml; MIC90 = 2 micrograms/ml. Serum erythromycin concentrations met or exceeded most MICs, with peak values of 3.05 to 3.69 and 1.92 to 2.9 micrograms/ml for the 40- and 25-mg/kg/day dosage groups, respectively. Pharmacokinetic parameters were calculated after the initial dose and at steady state for both dosage groups and compared. No adverse effects thought to be related to administration of erythromycin were observed. These preliminary findings showed that erythromycin is well-tolerated, has favorable pharmacokinetic activity in the preterm neonate and should be further investigated for treatment of ureaplasmal infections.

Association of post-cesarean delivery endometritis with colonization of the chorioamnion by Ureaplasma urealyticum.

OBJECTIVE: To determine if asymptomatic antenatal colonization of the chorioamnion with Ureaplasma urealyticum is a risk factor for the development of post-cesarean delivery endometritis. METHODS: The chorioamnion was cultured at cesarean delivery for aerobic and anaerobic bacteria, mycoplasmas, Chlamydia trachomatis, and Trichomonas vaginalis in 575 singleton gestations with intact membranes. Culture results were compared with the clinical outcome. Postoperative endometritis was defined as a temperature of 38C with uterine tenderness and without other nonpelvic sources of fever. RESULTS: Fifty-eight (10%) of the 575 women developed endometritis. Women with spontaneous labor developed endometritis twice as often as those delivered for medical or obstetric indications (17 versus 8%, P = .002). Endometritis occurred in 28% of women with U urealyticum present in the chorioamnion at cesarean delivery, compared with only 8.4% if the culture was negative and 8.8% if only bacteria other than U urealyticum were isolated (P < .001). Gestational age less than 34 weeks, spontaneous labor, and a vertical uterine incision were all associated with endometritis (P < or = .002). Regression analysis controlling for gestational age and incision type revealed a threefold increased risk of endometritis if the chorioamnion was colonized with U urealyticum at cesarean (odds ratio [OR] 3.0, 95% confidence interval [CI] 1.1-8.3) and an eightfold risk (OR 7.7, 95% CI 1.9-31.5) in women in whom the onset of labor was spontaneous. CONCLUSION: Colonization of the chorioamnion with U urealyticum in women with intact membranes being delivered by cesarean is a significant, independent predictor of subsequent endometritis.

Mycoplasma hominis septic thrombophlebitis in a patient with multiple trauma: a case report and literature review.

Mycoplasma hominis was recovered from the site of a septic thrombophlebitis on the left cephalic veins of a patient with pelvic and other multiple trauma. The organisms were initially isolated from routine cultures in conventional blood agar media incubated anaerobically. The absence of other demonstrable pathogens and the patient's serologic response to the isolate support the role of the organism as the cause of this previously unreported mycoplasmal infection. M. hominis should be considered a possible cause of sepsis in selected cases of infections following pelvic trauma or manipulations of the genitourinary tract.

Comparative susceptibility of Mycoplasma pneumoniae to erythromycin, ciprofloxacin, and lomefloxacin.

Lomefloxacin was found to be comparable to ciprofloxacin in its ability to inhibit the in vitro growth of Mycoplasma pneumoniae (MIC range 2-8 mcg/ml), but it was significantly less active than erythromycin. Although 30 different strains from widely differing geographic areas and isolation time periods were examined, no macrolide-resistant strains were observed.

Evaluation of the Etest for detection of tetracycline resistance in Mycoplasma hominis.

The Etest was compared with microbroth dilution for performing in vitro susceptibility tests in 38 isolates of Mycoplasma hominis chosen to represent a wide range of MIC values. MIC50s were 4 micrograms/ml for both methods; whereas, MIC90s were 64 and > 256 micrograms/ml for broth and Etest, respectively. Etest MICs determined on SP 4 agar were usually two or more dilutions greater than microbroth MICs in SP 4 broth, and values were prone to change by one to two dilutions when different inoculum densities were used. Inocula of 10(5) to 10(6) color-changing units/ml gave the most consistently readable MICs, with discrete colony formation surrounding the ellipse. Etest MICs for 5 isolates tested a second time at the same inoculum on SP 4 agar agreed with the original value within 1 dilution. For 12 isolates tested on A 8 agar simultaneously with SP 4 agar, MICs for 10/12 agreed within one dilution; whereas, in the other 2 isolates, MICs varied by two dilutions. These findings suggest that the Etest, when properly controlled, can be used to determine tetracycline MICs for M. hominis.

Phylogenetic analysis of Mycoplasma penetrans, isolated from HIV-infected patients.

A novel mycoplasmal species designated as Mycoplasma penetrans has recently been isolated from patients infected with human immunodeficiency virus. The 16S rRNA gene from this mycoplasma was cloned and its nucleotide sequence determined. This sequence was aligned with previously published homologous sequences from several mycoplasmas and with related Gram-positive bacteria and a phylogenetic tree was constructed. The results indicate that M. penetrans belongs to the evolutionary group Pneumoniae.

Rapid detection of tetM in Mycoplasma hominis and Ureaplasma urealyticum by PCR: tetM confers resistance to tetracycline but not necessarily to doxycycline.

Tetracycline resistance in Mycoplasma hominis and Ureaplasma urealyticum has been associated with the tetM determinant and has recently been increasing in incidence. We report here a rapid method for detection of the tetM determinant based on the use of the polymerase chain reaction (PCR) to amplify a 397-bp DNA fragment from the tetM gene and verification of specificity using the restriction enzyme TaqI. Analysis of 42 U. urealyticum and 49 M. hominis isolates indicates that the PCR method may be clinically useful for determination of tetracycline sensitivity, as tetM is presently the only known determinant associated with tetracycline resistance in these two organisms. All of the tetM-positive M. hominis isolates were sensitive to doxycycline, indicating that tetM does not necessarily confer resistance to this antibiotic.

The effects of three serotypes of Ureaplasma urealyticum on spermatozoal motility and penetration in vitro.

The effects of incubation of spermatozoa with three serotypes of Ureaplasma urealyticum on spermatozoal motility and penetration in vitro were investigated. Using computer-assisted video microscopy, three parameters of motility were determined: individual path lengths, individual vectorial distances, and percentage motility. Polyacrylamide gels were used as a medium for assessment of spermatozoal penetration. Ureaplasma-infected spermatozoa did have significantly greater path lengths and individual distances than did uninfected controls, but ureaplasma infection had no significant effect on percentage motility. Overall, there were no significant differences in penetration distances between ureaplasma-infected spermatozoa and their corresponding uninfected controls. Our conclusion is that the ureaplasmas did not adversely affect motility or penetration when spermatozoa were incubated with ureaplasmas for 45 minutes at ureaplasma:sperm ratios as high as 100:1.

Three views on faculty tenure in medical schools.

Three distinguished academicians share their thoughts on tenure and its future in academic medicine. Paul J. Friedman, from the University of California, San Diego, School of Medicine, explains and defends tenure as practiced in medical schools. He examines the question of giving tenure to clinical faculty, explains posttenure academic review, reports that the impending end of mandatory retirement will not have a significant effect on faculty turnover, and suggests that medical schools make the status of emeritus faculty more attractive. Next, Gail H. Cassell, from the University of Alabama School of Medicine, examines various beliefs about tenure and tenured faculty in the light of available studies, and concludes that many of the negative "myths" about the effect of tenure (e.g., promoting mediocrity and discouraging productivity) are not borne out by research findings. While she supports tenure, she maintains that better criteria are needed for awarding it; that the evaluation of faculty members' teaching needs much improvement; and that more research on tenure is needed. Finally, Richard A. Cooper, from the Medical College of Wisconsin, states that tenure should not continue, because the purposes of tenure (e.g., ensuring freedom of expression; providing long-term financial security and stability) should be and can be accomplished in other ways for all faculty, not just tenured faculty. A different system is needed, one that respects the value of all faculty, that responds to their diverse objectives, is fiscally responsible, and fosters the continuing culture and vitality of medical schools.(ABSTRACT TRUNCATED AT 250 WORDS)

Perinatal mycoplasmal infections.

Maternal infections are known to play a major role in perinatal morbidity and mortality. Ureaplasma urealyticum and Mycoplasma hominis are sexually transmissible microorganisms associated with a number of pathologic conditions in the pregnant woman including chorioamnionitis and postpartum fever. They are rapidly gaining recognition as significant causes of perinatal infection, especially in infants born prematurely. This review summarizes current knowledge regarding the epidemiology, pathology, disease spectrum, and clinical manifestations of mycoplasmal and ureaplasmal perinatal infections and presents guidelines for proper diagnosis and treatment.