- Email: [email protected]
Mycoplasma
1296
had completely healed and were dry. Her defunctioning ileostomy was closed and the fistula has remained healed. We recognise the difficulty that low pouch-vaginal fistulae are likely to cause as restorative pouch proctocolectomy becomes more widely accepted. Our technique seems to offer the prospect of a cure for female patients, and we recommend it to our colleagues. N. I. MARKHAM G. M. WATSON M. R. LOCK
Whittington Hospital, London N19 5NF, UK
1. Martius H. The repair of vesico-vaginal fistulae with interposition pedicle graft of labial tissue. Zautnalblatt Gynaekol 1928; 52: 480.
Mycoplasma SIR,-Your March 16 editorial (p 651) on Myocplasma pneumoniae did not mention reports of M genitalium and Mpnewnoniae in throat specimens of some individuals with mycoplasmal pneumonia.’ These observations could have important implications for the clinical and laboratory diagnosis of M pneumoniae infection, and may even raise some question about
genitalium in mycoplasmal pneumonia and the extrapulmonary complications of this disease. The isolation of Mgenitalium from the urethra in non-gonococcal
the role of M
urethritis (NGU) was first reported in The Lancet in 1981,2 and we now know more about the cytopathogenicity of this organism and about its ability to colonise the lower genital tract of both male and female chimpanzees.1 Unfortunately, a role for the organism in human NGU has yet to be established. We found failure to culture additional strains of M genitalium from the urogenital tract as suggestive that this was unlikely to be the primary colonisation site--m impression that seemed to be confirmed when M genitalium and M pneumoniae were simultaneously identified in the respiratory tract of some inpatients with mycoplasmal pneumonia.1 Discovery of both organisms was facilitated by work on adhesins, proteins on the surface of the specialised terminal structure of some myoplasmas that mediate attachment to host epithelial cells. The M pnewnoniae PI adhesin is quite distinct from the one found in M genitalium, so demonstration of both in cell protein profiles, with monoclonal antibodies,3 indicated the presence of both Mycoplasma spp. The mixed populations were separated by mycoplasma cloning and the purified isolates were confirmed by serological analysis and adhesin profiles. Further clinical evidence of mixed M pneumoniae and M genitalium comes from our observation (unpublished) of both organisms in the synovial fluid of a patient with polyarthritis after primary pneumonia. The isolate, cultivated on mycoplasma culture medium SP-4, was at first identified as M pneumoniae but when we re-examined the culture we purified from it both M pneumoniae and
M gerraitalium. We agree that
serological techniques are the primary means to diagnose M pneumoniae infection, and that the complement fixation test (CFT) lacks specificity and sensitivity. The CFT cannot distinguish M pneumoniae from M genitalium. The glycolipid antigens of these two organisms are very similar. Indeed, a CFT using M genitalium antigen will give antibody titres indistinguishable from a test using M pneumoniae CFT antigen in sera from patients with established M pneumoniae infection, or with various hyperimmune sera to this organism. Further evidence of shared cross-reactions in serological tests has been reported,4 including shared membrane proteins and cross-reacting epitopes between their adhesin proteins Earlier, CFT cross-reactions could perhaps have been dismissed as not relevant to the diagnosis of mycoplasmal pneumonia because M genitalium was thought to occur only in the human genital tract. However, it now seems clear that the
current
CFT will
never
differentiate between the
two
mycoplasmas. Your editorial mentions new serological and antigen detection techniques for M pneumrnriae that provide "a more reliable indicator of recent infection". However, all the reports we have reviewed either ignore M genitalium or dismiss it by citing the lack of evidence that it is involved in respiratory disease. It is difficult to see how aetiological relations can be worked out without a test to
differentiate the two organisms. In many reports documentation of infection with isolation of the organism(s) was based on suboptimum medium formulations and appeared to lack quality contol on medium ingredients. We think it unlikely that a diagnostic test based on serum antibodies or existing antigen detection methods will be specific enough to separate immune responses to each organism or sensitive enough to detect 100-1000 mycoplasmas in clinical specimens. cDNA probe procedures may have similar deficiencies. The most widely used commercial kit (’Gen-Probe’) cannot distinguish between Mgenitalium and M pneumrnziae and can detect levels only from 50 000-100 000 organisms.s The diagnostic technique of the future, to establish M pneumoniae and/or Mgenitalium infectons, will probably involve genome amplification procedures. The full nucleotide sequences of the dominant adhesin proteins are known, and gene fragments specific for each organism can be selected as primers. Preliminary reports on this approach have been published.6-8 Another diagnostic approach could make use of unique epitopes on the adhesins3 or other components of these mycoplasmas9 as antigens in serological testing. Eventual application of these techniques to clinical testing should include laboratory cultivation of both M pneumoniae and Mgenitalium (on recommended medium formulations) from respiratory tract specimens. These laboratory techniques and clinical studies could then provide important new information on the role of M genitalium in the respiratory tract and other tissue sites and on its interactions with M pneumoniae in the aetiology of
mycoplasmal pneumonia. Mycoplasma Section, National Institute of Allergy and Infectious Diseases, Frederick Cancer Research
Development Center, Frederick, Maryland 21701, USA
JOSEPH G. TULLY
Department of Microbiology, University of Texas Health Science Center, San Antonio, Texas
JOEL B. BASEMAN
1. Baseman JB, Dallo SF, Tully JG, et al. Isolation and characterization of Mycoplasma genitalium strains from the human respiratory tract. J Clin Microbiol 1988; 26: 2266-69. 2. Tully JG, Taylor-Robinson D, Cole RM, et al. A newly discovered mycoplasma in the human urogenital tract. Lancet 1981; i: 1288-91. 3. Morrison-Plummer J, Lazzell A, Baseman JB. Shared epitopes between Mycoplasma pneumomae major adhesin protein P1 and a 140 kilodalton protein of Mycoplasma gemtalium. Infect Immun 1987; 55: 49-56. 4. Taylor-Robinson D, Furr PM, Tulley JG. Serological cross-reactions between Mycoplasma genitalium and M pneumomae. Lancet 1983; i: 527. 5. Shaw SB. DNA probes for the detection of Legionella species, Mycoplasma pneumomae, and members of the Mycobacterium tuberculosis complex. In. DNA probes for infectious diseases. Boca Raton: CRC Press, 1989: 101-17. 6. Bernet C, Garret M, De Barbeyrac B, et al. Detection of Mycoplasma pneumoniae by using the polymerase chain reaction. J Clin Microbiol 1989; 27: 2492-96. 7. Jensen JS, Uldum SA, Sondergard-Andersen J, et al. Polymerase chain reaction for detection of Mycoplasma genitalium in clinical samples.J Clin Microbiol 1991; 29: 46-50. 8. Palmer HM, Gilroy CB, Furr PM, et al. Development and evaluation of the polymerase chain reaction to detect Mycoplasma genitalium. FEMS Microbiol Lett 1991; 77: 199-204. 9. Morrison-Plummer J, Jones DH, Daly K, et al. Molecular characterization of Mycoplasma genitalium species-specific and cross-reactive determinants: identification of an immunodominant protein of M genitalium. Israel J Med Sci
1987; 23: 453-57.
Abnormal transcranial
pregnant
doppler pattern in a during orthostatic hypotension
woman
SIR,-Cerebral blood-flow (CBF) velocity can be evaluated by transcranial doppler ultrasonography. Middle cerebral artery (MCA) blood-flow velocity is lower with the patient in the upright than in the horizontal position,l and orthostatic hypotension has been associated with transient reductions of mean MCA blood-flow velocities and inconsistent changes of CBF (table). We know of no reports of CBF velocity waveforms during an acute episode of orthostatic hypotension. A 28-year-old primipara with no evidence for cardiac, cerebral, or cerebrovascular disease had an uneventful pregnancy until the 30th
had completely healed and were dry. Her defunctioning ileostomy was closed and the fistula has remained healed. We recognise the difficulty that low pouch-vaginal fistulae are likely to cause as restorative pouch proctocolectomy becomes more widely accepted. Our technique seems to offer the prospect of a cure for female patients, and we recommend it to our colleagues. N. I. MARKHAM G. M. WATSON M. R. LOCK
Whittington Hospital, London N19 5NF, UK
1. Martius H. The repair of vesico-vaginal fistulae with interposition pedicle graft of labial tissue. Zautnalblatt Gynaekol 1928; 52: 480.
Mycoplasma SIR,-Your March 16 editorial (p 651) on Myocplasma pneumoniae did not mention reports of M genitalium and Mpnewnoniae in throat specimens of some individuals with mycoplasmal pneumonia.’ These observations could have important implications for the clinical and laboratory diagnosis of M pneumoniae infection, and may even raise some question about
genitalium in mycoplasmal pneumonia and the extrapulmonary complications of this disease. The isolation of Mgenitalium from the urethra in non-gonococcal
the role of M
urethritis (NGU) was first reported in The Lancet in 1981,2 and we now know more about the cytopathogenicity of this organism and about its ability to colonise the lower genital tract of both male and female chimpanzees.1 Unfortunately, a role for the organism in human NGU has yet to be established. We found failure to culture additional strains of M genitalium from the urogenital tract as suggestive that this was unlikely to be the primary colonisation site--m impression that seemed to be confirmed when M genitalium and M pneumoniae were simultaneously identified in the respiratory tract of some inpatients with mycoplasmal pneumonia.1 Discovery of both organisms was facilitated by work on adhesins, proteins on the surface of the specialised terminal structure of some myoplasmas that mediate attachment to host epithelial cells. The M pnewnoniae PI adhesin is quite distinct from the one found in M genitalium, so demonstration of both in cell protein profiles, with monoclonal antibodies,3 indicated the presence of both Mycoplasma spp. The mixed populations were separated by mycoplasma cloning and the purified isolates were confirmed by serological analysis and adhesin profiles. Further clinical evidence of mixed M pneumoniae and M genitalium comes from our observation (unpublished) of both organisms in the synovial fluid of a patient with polyarthritis after primary pneumonia. The isolate, cultivated on mycoplasma culture medium SP-4, was at first identified as M pneumoniae but when we re-examined the culture we purified from it both M pneumoniae and
M gerraitalium. We agree that
serological techniques are the primary means to diagnose M pneumoniae infection, and that the complement fixation test (CFT) lacks specificity and sensitivity. The CFT cannot distinguish M pneumoniae from M genitalium. The glycolipid antigens of these two organisms are very similar. Indeed, a CFT using M genitalium antigen will give antibody titres indistinguishable from a test using M pneumoniae CFT antigen in sera from patients with established M pneumoniae infection, or with various hyperimmune sera to this organism. Further evidence of shared cross-reactions in serological tests has been reported,4 including shared membrane proteins and cross-reacting epitopes between their adhesin proteins Earlier, CFT cross-reactions could perhaps have been dismissed as not relevant to the diagnosis of mycoplasmal pneumonia because M genitalium was thought to occur only in the human genital tract. However, it now seems clear that the
current
CFT will
never
differentiate between the
two
mycoplasmas. Your editorial mentions new serological and antigen detection techniques for M pneumrnriae that provide "a more reliable indicator of recent infection". However, all the reports we have reviewed either ignore M genitalium or dismiss it by citing the lack of evidence that it is involved in respiratory disease. It is difficult to see how aetiological relations can be worked out without a test to
differentiate the two organisms. In many reports documentation of infection with isolation of the organism(s) was based on suboptimum medium formulations and appeared to lack quality contol on medium ingredients. We think it unlikely that a diagnostic test based on serum antibodies or existing antigen detection methods will be specific enough to separate immune responses to each organism or sensitive enough to detect 100-1000 mycoplasmas in clinical specimens. cDNA probe procedures may have similar deficiencies. The most widely used commercial kit (’Gen-Probe’) cannot distinguish between Mgenitalium and M pneumrnziae and can detect levels only from 50 000-100 000 organisms.s The diagnostic technique of the future, to establish M pneumoniae and/or Mgenitalium infectons, will probably involve genome amplification procedures. The full nucleotide sequences of the dominant adhesin proteins are known, and gene fragments specific for each organism can be selected as primers. Preliminary reports on this approach have been published.6-8 Another diagnostic approach could make use of unique epitopes on the adhesins3 or other components of these mycoplasmas9 as antigens in serological testing. Eventual application of these techniques to clinical testing should include laboratory cultivation of both M pneumoniae and Mgenitalium (on recommended medium formulations) from respiratory tract specimens. These laboratory techniques and clinical studies could then provide important new information on the role of M genitalium in the respiratory tract and other tissue sites and on its interactions with M pneumoniae in the aetiology of
mycoplasmal pneumonia. Mycoplasma Section, National Institute of Allergy and Infectious Diseases, Frederick Cancer Research
Development Center, Frederick, Maryland 21701, USA
JOSEPH G. TULLY
Department of Microbiology, University of Texas Health Science Center, San Antonio, Texas
JOEL B. BASEMAN
1. Baseman JB, Dallo SF, Tully JG, et al. Isolation and characterization of Mycoplasma genitalium strains from the human respiratory tract. J Clin Microbiol 1988; 26: 2266-69. 2. Tully JG, Taylor-Robinson D, Cole RM, et al. A newly discovered mycoplasma in the human urogenital tract. Lancet 1981; i: 1288-91. 3. Morrison-Plummer J, Lazzell A, Baseman JB. Shared epitopes between Mycoplasma pneumomae major adhesin protein P1 and a 140 kilodalton protein of Mycoplasma gemtalium. Infect Immun 1987; 55: 49-56. 4. Taylor-Robinson D, Furr PM, Tulley JG. Serological cross-reactions between Mycoplasma genitalium and M pneumomae. Lancet 1983; i: 527. 5. Shaw SB. DNA probes for the detection of Legionella species, Mycoplasma pneumomae, and members of the Mycobacterium tuberculosis complex. In. DNA probes for infectious diseases. Boca Raton: CRC Press, 1989: 101-17. 6. Bernet C, Garret M, De Barbeyrac B, et al. Detection of Mycoplasma pneumoniae by using the polymerase chain reaction. J Clin Microbiol 1989; 27: 2492-96. 7. Jensen JS, Uldum SA, Sondergard-Andersen J, et al. Polymerase chain reaction for detection of Mycoplasma genitalium in clinical samples.J Clin Microbiol 1991; 29: 46-50. 8. Palmer HM, Gilroy CB, Furr PM, et al. Development and evaluation of the polymerase chain reaction to detect Mycoplasma genitalium. FEMS Microbiol Lett 1991; 77: 199-204. 9. Morrison-Plummer J, Jones DH, Daly K, et al. Molecular characterization of Mycoplasma genitalium species-specific and cross-reactive determinants: identification of an immunodominant protein of M genitalium. Israel J Med Sci
1987; 23: 453-57.
Abnormal transcranial
pregnant
doppler pattern in a during orthostatic hypotension
woman
SIR,-Cerebral blood-flow (CBF) velocity can be evaluated by transcranial doppler ultrasonography. Middle cerebral artery (MCA) blood-flow velocity is lower with the patient in the upright than in the horizontal position,l and orthostatic hypotension has been associated with transient reductions of mean MCA blood-flow velocities and inconsistent changes of CBF (table). We know of no reports of CBF velocity waveforms during an acute episode of orthostatic hypotension. A 28-year-old primipara with no evidence for cardiac, cerebral, or cerebrovascular disease had an uneventful pregnancy until the 30th