the Editor

MUCOCUTANEOUS REACTIONS DURING MYCOPLASMA PNEUMONIÆ INFECTION SIR,-Mycoplasma pneumonia is a common respiratorytract pathogen and a frequent cause of non-bacterial pneumonia.’ It can also give rise to symptoms outside the respiratory tract, and symptoms associated with a M. pneumonia, infection include abnormalities of the central nervous system,

pericarditis, myocarditis, arthritis, and,



reactions.!,2 An association between M. pneumonice infection and exanthemas may be more common than


is generally appreciated.3 At this laboratory we

test blood specimens for complement-fixing antibodies to M. pneumonia and for cold agglutinins for all hospitals and general practitioners in Denmark. The presence of M. pneumonia antibodies with cold agglutinins indicates a current M. pneumoniae infection.!,4 The incidence of such cases varies greatly over the years.5 For the period March 1, 1969, to Dec. 31, 1974, we asked for the clinical findings on patients whose blood had contained cold agglutinins, and we received information on 2544 patients. 869 of these had a positive M. pneumonice antibody test while this was negative in the remaining 1675 patients. The

table shows the distribution of various mucocutaneous syndromes and exanthemas among 100 patients (11.5%) in the mycoplasma-positive group and among 96 (5.7%) in the mycoplasma-negative group. Lesions of the skin and mucous membranes were significantly more frequent among mycoplasma-antibody-positive patients, and this was true of StevensJohnson syndrome and unspecified exanthema and urticaria but not of stomatitis (with or without urethritis), erythema multiforme, erythema nodosum, or Schonlein-Henoch purpura.

mycoplasma-positive patients were younger (average 9 than the mycoplasma-negative group (26 years), but reports of Stevens-Johnson syndrome were not exclusively agedependent, 16 mycoplasma-positive patients with this syndrome ranging in age from 6 to 48 (mean 15) while the 4 mycoplasma-negative patients were 8, 19, 34, and 69 years old. The figures for pneumonia in the two groups exclude a role for pneumonia as provocative factor for the mucocutaneous manifestations. The


1. Foy, H. M., Grayston, J. T. in Communicable and Infectious Diseases (edited by F. H. Top, P. F. Wehrle); p. 480. St. Louis, 1972. 2. Dorff, B., Lind, K. Scand.J. infect. Dis. 1976, 8, 49. 3. Cherry, J. D., Hurwitz, E. S., Welliver, R. C.J. Pediat. 1975, 87, 369. 4. Lind, K. Mycoplasma pneumoniœ Infection: Serological, Aetiological and Epidemiological Studies. Copenhagen, 1973. 5. Lind, K., Bentzon, M. W. Int. J. Epidemiol. 1976, 5, 267. 6. Foy, H. M., Kenny, G. E., McMahan, R., Mansy, A. M., Grayston, J. T. J. Am. med. Ass. 1970, 214, 1666.

Skin reactions did occur when no drug had been given but where there was an association the possibility that the drug might have provoked or intensified the skin or mucous membrane reactions cannot be ruled out. In a 5-year surveillance study in Seattle5 17% of 319 M. pneumoniae patients had a rash while this skin lesion was found in only 9% of 485 patients whose pneumonia was caused by some other organism. There were no cases of Stevens-John-

syndrome. Cherry reported


that 16 out of 20 patients with M. pneumonice infection associated with exanthem were males, a sex ratio which contrasts with ours (1:1). We concluded that symptoms of the skin and mucous mem-

branes, particularly Stevens-Johnson syndrome,



likely in a cold-agglutinin associated respiratory infection when it is caused by M. pneumonire rather than other pathogens. We do not know if these symptoms are more frequent in patients with M. pneumonice infections who have cold agglutinins than in those who do not. Mycoplasma Laboratory, Blood Bank and Blood Grouping Department, Statens Seruminstitut, DK 2300 Copenhagen

S, Denmark



SIR,-Transferability of drug resistance in streptococci of group D is common,1-4 but despite the extrachromosomal nature of resistance to several antibiotics in streptococci of group As·6conjugal transfer to or between group-A streptococci has not been achieved.4s We have investigated the transferability of some drug-resistance plasmids, originating from two Streptococcus fcecalis strains, io group A and B streptococci. No or very poor transfer of drug resistance was found when bacterial matings were done in liquid medium, but positive results were obtained in filter matings. The tetracycline resistance determinant from Strep. faecalis strain M 440 was transferred to group-A streptococci with low frequency and no further transfer from streptococcal group A was observed. No tetracycline resistance transfer to group B or D strains was found. However, the erythromycin resistance of strain M440 was transferable to the groups A, B, and D and could be retransferred to strains of all three serogroups. When donor and recipient were different in serogroup, the transfer frequency was low, but a highly efficient transfer was found between streptococci of the same group. The results may be 1. 2. 3. 4.

Jacob, A. E., Hobbs, S. J.J. Bact. 1974, 117, 863. Dunny, G. M., Clewell, D. B. ibid. 1975, 124, 784. Marder, H. P., Kayser, F. H. Antimocrob. Ag. Chemother. 1977, 12, 261. van Embden, J. D. A., Engel, H. W. B., van Klingeren, B. ibid. 1977, 11,

925. 5. Clewell, D. B., Franke, A. E. ibid. 1974, 5, 534. 6. Malke, H., Jacob, H. E., Stärl, K. Molec. gen. Genet. 1976, 144, 333.


656 summarised a

as follows, transfer frequencies being recorded as proportion of the total recipients. Frequencies below 1 x 10-8


taken as "no transfer detectable".


erythromycin resistance determinant was transferred from Strep. fcecalis M440 as follows: (1) To group A (5 x 10-6) and then to both group B (3 x 10-’), with third and fourth transfers to group A (2 x 10-3 and 4 x 10-3 ,respectively), and to group D (4 x 10-s) also with third and fourth transfers to group A (4 x10-6 and 3 x 10-3). (2) To group B (3x10-’) with second transfer to group B (2x10-’) and D (3x10-). (3) To group D (1 x 10-2) with second transfer to group D (1 x 10-2). The tetracycline resistance determinant was transferred to group A (1x10) but not, in second transfers, to groups B or D, and first transfers to groups B and D also failed.

Conjugation seems the most likely mechanism of transfer, because transfer failed with cell-free filtrates of donor cultures, which makes transduction unlikely, and because transfer was not prevented by mating in the presence of high concentrations (300 g/ml) of D.N.A.se plus 10 mmol/1 magnesium chloride, indicating that transformation is also unlikely. Transfer of erythromycin resistance was accompanied by the gain of plasmid D.N.A. in recipient cells. Electron microscopy of this plasmid D.N.A. showed the presence of a homogeneous species corresponding to a molecular weight of 16-17 x 106. The size of this plasmid is close to the 20 x 106 found for two erythromycin resistance plasmids also originating from group-D streptococci and shown to be transferable to other group-D recipients.7 Erythromycin resistance plasmids of similar size have been found in other streptococci of group D28 and also in group A,5.6 but the plasmids tested seemed to lack the capacity to promote conjugal transfer. However, the mating conditions in these experiments (liquid medium) were unfavourable and transferability of plasmids cannot be ruled

Webb et al. claim to have measured the calibre of the portal vein at its broadest point, at the conjunction of the splenic and superior mesenteric veins: this is usually anterior to the vena cava or slightly to the left of it. We feel that this measurement should be made on ultrasonograms in which the portal vein appears in front of the vena cava; at this level it is always easily recognisable both in transverse and in longitudinal sections. We were surprised to see that in fig. 1 of Webb’s paper a liquid formation located in the right hypocondrium was indicated as a normal portal vein; the diameter of this liquid formation seems larger than the 6.3±2-3 mm indicated as the normal mean calibre. From its position and appearance this liquid formation could simply be a normal gallbladder. The portal vein is clearly visible in the same picture, in front of the vena cava.

To obtain

complete visualisation of the vessel we use progressively oblique scans until we get a longitudinal section that encloses the whole vessel (fig. 1). Webb et al. state that it is often possible to show the right and left branch division, but they do not say how this can be done: we suggest oblique scans parallel to the costal arch, inclining the transducer below it. Of the two branches, the right portal vein is sectioned transversely by the longitudinal scans, and it is always clearly recognisable near the porta hepatis because it is surrounded by a thick band of echoes, which disa



The transferability of resistance plasmids from group D to the virulent group A and group B streptococci could be a health hazard. The large-scale use of macrolide antibiotics and virginiamycin for growth promotion in animal husbandry might be undesirable. As we suggested earlier,4use of these antibiotics could result in the build-up of a reservoir of macrolide-resistant indigenous group-D streptococci in animals. This kind of selection happens with gram-negative enteric flora and it has also been found for group-D streptococci as a result of feeding tetracycline-containing-diets to broiler fowl.9 Silver has found that the use of virginiamycin in the diet of beagle dogs quickly led to the replacement of the sensitive flora by a population of enterococci resistant to erythromycin.’ Resistant enterococci might be transferred to man by consumption of contaminated meat products or animal handling. The host range of resistance plasmids might be of potential significance in human therapy because of the potential of transfer of resistance to pathogenic streptococci such as Strep. pyogenes (group A) or Strep. agalactiae (group B). The latter group also causes mastitis in certain livestock. J. D. A. VAN EMBDEN National Institute of N. SOEDIRMAN Public Health, P.O. Box 1, Bilthoven, Netherland

Fig. 1--Oblique section. The portal vein (white arrows)

is well visualised over a it passes just anterior to the vena cava (black arrows).

long stretch:


ULTRASONOGRAPHY IN ASSESSMENT OF PORTAL VENOUS SYSTEM et al.’ on the use of ultrasound visualise the splenic and portal veins is of great interest. We also believe that this simple, safe, and rapid technique has an important place in the diagnosis of extrahepatic portal venous obstruction and portal hypertension.

SIR,-The article by Webb


7. Silver, R. P. Personal communication. 8. Corb, M. M., Murray, M. L. F.E.M.S. microbiol. Letters, 1977, 1, 351. 9. Lebduska, J., Bartas, J. Docum. vet. Brno, 1975, 8, 179. 1. Webb, L. J., Berger, L. A., Sherlock, S. Lancet, 1977, ii, 675.

Fig. 2-Longitudinal section. Dilated superior mesentenc vein in patient with portal hypertension visualised as far as the conjunction with the portal vein.

(black arrows)

Transferable drug resistance to group A and group B streptococci.

655 Letters to the Editor MUCOCUTANEOUS REACTIONS DURING MYCOPLASMA PNEUMONIÆ INFECTION SIR,-Mycoplasma pneumonia is a common respiratorytra...
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