MICROCOCCUStETRAGENUSINFECTION

I. REVIEW OF THE LITERATURE, REPORTOF A NON-FATAL CASE WITH SEPTICEMIA,MENINGITIS AND ARTHRITIS, AND BACTERIOLOGIC STUDIES

BY HOBARTA. REIMANN(From Department of Medicine, University of Minnesota Hospital, Minneapolis)

(Received for publication November 28, 1934)

The appearance of only two or three reports(Greiwe, et al. (1), Steele (1)) of Micrococcustetragenus infection in American medical litera-ture would lead one to believe the disease to berare and of little importance. It is probably quitecommon, but often disregarded or unrecognizedin this country. More than 170 cases have beenreported in Italian, French, German, English andSpanish journals.

Micrococcus tetragenus, after its discovery in1881 by Koch and Gaffky, was believed to be aharmless saprophyte residing in the normal naso-pharynx and often in tuberculous cavities in thelung. Its pathogenicity was first recorded byJakowski (2) in 1886. Later Mya and Tram-busti (3) reported two cases of septicemia, andViquerat (4) produced suppuration by injectingcultures of M. tetragenus into blister sacs ontuberculous patients. The organism is, however,of comparatively low virulence and becomes in-vasive only under certain conditions in which theresistance of the host is reduced. When infec-tion does occur, it resembles the local suppura-tion or septicemia with metastatic localization dueto the closely related staphylococcus. The organ-ism appears to have a predilection for serousmembranes, but also invades parenchymatousorgans.

All of the published reports, except two, dealwith sporadic cases. Two small epidemics havebeen reported among soldiers during the WorldWar; one by Birks, Thornley and Fawcus (5)who observed 25 cases of septicemia, and one byTremolieres and Loew (5) with 45 cases. Inboth series the mortality rate was low and thegeneral features illustrated the importance ofpredisposing factors. In many of the cases, M.tetragenus was probably a secondary invader.

Clinically, the infection is characterized byfeatures common to pyogenic infections due to

other cocci. The case reported here conforms tothe prototype of the usual course. A brief sum-mary of certain salient features of the disease,taken from reports giving adequate data in avail-able journals, is given in Table I. Many Frenchand Italian articles (6) are short and devoid ofdetails.

The infection is apparently commonest inyoung adults. The onset is usually abrupt andis almost invariably preceded by some predispos-ing cause which presumably lowers resistance andmakes invasion possible. Sore throat and re-spiratory tract infections are the commonest, aswould be expected, since M. tetragenus often re-sides in the normal nasopharynx. Other pre-disposing factors are anemia (Mya and Tram-busti (3), Arullani (7), Brugnola (1)), abscesses(Jakowski (2), Viquerat (4), Achard and Gail-lard (8), Steele (1) and others) and urinarytract infections (Gayet (9) and others). Inter-esting cases have been observed both precedingand following typhoid fever (Anglada (7),Laignel-Lavastine and Baufle and Meltzer (1)),several accompanying septicemia due to strepto-cocci (Meltzer (1)) and one with brucelliasis(10). The course of the infection may be mild orsevere and is characterized by chills, sweats, re-mittent fever, moderate leukocytosis and often bysplenomegaly. Fulminating cases have endedfatally on the seventh day (Leschke (1)), andprotracted cases may last 7 months (Castaigne(1)). The mortality rate judged from 44 casesof septicemia in which the outcome is stated is50 per cent.

Reports of more than 127 cases of septicemiaare available, many of which also show localiza-tion in various parts of the body. Cases withsepticemia alone are referred to in Table I andare reported in the papers of Mya and Trambusti(3), Arullani, Boni, Anglada, Tillaye, Marcora

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HOBARTA. REIMANN

TABLE I

Summary from literature of features of Micrococcus tetragenus infection

Sex Age Predisposing Onset Dura- outcome Septi- Arthritis Menin- Other | Otherfactor tion cemia gitis localization observations

Cases with arthritis

Chauffard, A., and F. 15 Influenza Gradual 11 days Fatal + + Endocardi- ExanthemRamond,F.,Arch. M. 18 Sudden 10 days Fatal + + tis Bronchitis, empy-de med. Exper., ema1896, 8, 304

Bertaux, A., cited M. 37 Sore throat Recovered + + Pneumonia,by Lartigau (13) phlebitis

Faisans and Le Da- Sore throat Fatal + Pneumonia,many, Semana empyema,m&d., 1897, 17, exanthem2S8

von Ofenheim, E., M. 38 Abscess Gradual S months Recovered + + Exanthem Typhoid fever andProc. Roy. Soc. rheumatic feverMed., Clin. Sect., first considered.1909, 2, 164 No specific agglu-

tinins; treatedwith vaccine

Stroebel, Beitr. z. M. 26 Thoracotomy Sudden Recovered + +klin. Chir., 1913,83, 718

Leschke, E., Spez. M. 23 Sore throat Sudden 7 days Fatal + + +Path. u. Therap.Kraus, Brugsch.,1919, 2, 1103

This report M. 46 Sore throat Sudden 7 weeks Recovered + + + Prostate Rheumatic feverand gonorrhealarthritis first con-sidered. No ag-glutinins. Skintest negative

Cases with pneumonia or empyema

Castaigne, J., Bull. F. Fractured leg Gradual 7 months Fatal + Spleen andSoc. Anat., 1897, kidney ab-11, 394 scess

Bosc, F. J., and M. 45 FatalGalavielle, L.,Arch. de med.Exper., 1899, 11,70

Bosc, F. J., Arch. M. 21 Long illness, Sudden Fatal + Peritonitis,de med. Exper., anemia entero-1900, 12, 159 colitis

Byers, J., and Hous- M. 11 A "cold" Sudden + Exanthemton, T., Lancet,1913, 1, 1723

Cases with meningitis

Bezancon, F., and F. 32 Following Fatal + +Liepage, Semana childbirthme'd., 1898, 18, 40

Greiwe, J. W., Fack- M. 35 Sudden 3 weeks Fatal +ler, G. A., andMitchell, E. W.,Phila. Month.Med. J., 1899, 1,528

Pende, N., Cen- F. 48 Previously well Sudden S weeks Fatal +tralbl. f. Bakt.,Ref., 1908, 41,294

Bonanno, A. M., M. 28 Sudden 4 weeks Recovered None + Believed at first toRif orma med., be brucelliasis1931, 47, 363

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MICROCOCCUSTETRAGENUSINFECTION

TABLE I (continued)

Sex Ae factor Onset Dumn Outcome Septi- Arthritis | Menin I Other Otherfacortion cemia gitis localization -observationsCases with sePticemia with miscdlaneous localisation

"vs.Luigi, Fornaca, Ri- M. 45 Sudden 6 months Recovered + Empyema

forma med., 1903,19, 309 and 346

Brugnola, A., Ri- F. 40 Anemia Gradual 6 weeks Recovered + Patient not ill,forma med., 1906, F. 21 Anemia Gradual - Recovered + afebrile22, 957

Debove, Presse F. 33 Old endocarditis Gradual Months Fatal + Acute endo-med., 1907, 15, 41 carditis

Ziegler. K., Miln- F. 17 Sore throat Sudden Recovered +chen med. Wchn-schr., 1908, 55,2487

Laignel-Lavastine F. 26 Typhoid fever Sudden 1 week Recovered + Occurred 12 daysand Baufle, P., after typhoid fe-Compt. rend. Soc. verde biol., 1909, 67,661

Caldera, C., and Pi- M. 16 Chronic mas- Sudden Fatal + Empyema,naroli, G., Arch. toiditis lung gan-ital. di otol., 1911, grene22, 34

Steele, A. E., M. 24 14 Fatal + TibialJ.A.M.A., 1914, weeks abscess62, 930

Lfidke,H.,Mfinchen M. 21 Sore throat Gradual 17 days Recovered + Petechia Given specific vac-med. Wchnschr., M. 34 Typhoid fever Sudden Recovered + cine1920, 67, 454 M. 41 Sore throat Recovered +

Kramar, E., Arch. 31 3 months Recovered + Specific agglutininsf. Kinderh., 1930, mos. in serum, 1-64092, 248

Adel, F., Med. Klin., M. 31 A "cold" Gradual 2 months Fatal + Petechia, First believed to be1931, 27, 129 endocardi- tuberculosis

tisBattistini, G., Ri- F. 24 Sore throat Gradual 5 months Recovered + Arthralgia First believed to be

forma med., 1931, rheumatic fever.47. 646 Treated with vac-

cine

Meltzer, O., M. 35 Gradual 5 weeks Recovered + Specific agglutininsMtinchen medA in serum 1-500Wchnschr., 1910, F. 27 Postpartum Sudden 9 days Fatal + Streptococci in57, 743 blood

F. 24 Postpartum Sudden 4 months ? + Streptococci inblood

Looten, J., and Oui, F. 24 Difficult labor Gradual 6 weeks Recovered + Arthralgia Puerperal infectionAnn. d. Gynec.,1909, 6, 134

(7), Ceraulo-Vetrano (10), Tremolieres, Birks(5), Gayet (9) and others. Cases with localiza-tion in various parts of the body other than thoselisted in Table I are mentioned by the followingauthors: arthritis by Oettinger, Roger and Tre-molieres ( 11 ); meningitis by Vincent ( 12), Oet-tinger (11), Ramond (16), Rosenthal, vonRiemsdk and Blum (12); respiratory tract le-sions including mouth infections, pharyngitis,otitis media, bronchitis, pneumonia and empy-ema by Apert, Lewy, Lartigau, Park, Karlinsky,Steinhaus, Kapper, Netter, Delearde (13), Tre-molieres (5) and Kimmerle (14); endocarditis

by Sterling (15), Gaucher, Perfetti (16), Len-hartz, Meyer (17) and pericarditis by Benoit(13); puerperal infection by Cathala and Gueniot(18), Bondy, Hussy, Wegelius (7); peritonitisby Pane (3) and Muller (19); perinephritic ab-scess by Vease (16); and pyosalpinx by Woll-green (7). Battistini (1) reported glomerulone-phritis during septicemia and cultivated M. tetra-genus from the patient's urine. Exanthematahave been noted by Chauffard and Ramond, Fai-sans and Le Damany, Adel, von Ofenheim, Byersand Houston, Liidke and Stroebel (1). Gaucher(16) noted purpura.

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HOBARTA. REIMANN

Only a few immunologic studies on patientshave been made. Specific agglutinins were foundin the serum by Meltzer, Brugnola (1) Tre-molieres (5) and Kram'ar (1); von Of enheim andDebove (1) were unable to demonstrate signifi-cant titers. Several authors report beneficial ef-fects from vaccine therapy (Liidke, Battistini (1),Gayet (9)), others were unsuccessful (von Ofen-heim (1)). Vaccine therapy in experimentalanimals was ineffectual (Lambea (20)).

Diagnosis.-Since the infection follows otherdiseases, as it often does, it is difficult to recog-nize for there are no pathognostic features asidefrom those common to other pyogenic infections.It has been confused with rheumatic fever, gonor-rheal arthritis, tuberculosis, typhoid fever, malariaand sepsis due to other pyogenic cocci, especiallythe staphylococcus. At present, etiologic diag-nosis can only be made by the isolation and identi-fication of M. tetragenus from the blood or fromother foci of infection.

CASE REPORT

On June 14 and 15, G. J., a fisherman, aged 46, drankalcoholic liquor excessively and awoke on the morning ofthe sixteenth feeling ill with a severe sore throat, head-ache, and alternating chilliness and sweating. He wentto work, but soon became worse and retired because of

C39.9039.438.938.337.837.336.836.2

FMA

knee was slightly swollen and painful. The overlyingskin was neither reddened nor hot. The heart and lungswere normal. The prostate was tender but not enlargedand several drops of viscid white pus were expressedfrom the urethra on two occasions. No abnormal neu-rologic signs were noted. The clinical impression wasacute rheumatic fever or gonorrheal arthritis.

Course. The arthralgia and fever were uninfluencedby amidopyrine. On June 27, the tenth day of illness,the right knee became larger and 40 cc. of mucinous,lemon yellow, turbid pus was aspirated. The right wristwas aspirated but no pus was obtained. The knee wasaspirated again on the eighteenth and twenty-seconddays; 60 cc. and 9 cc. of pus were removed. The pa-tient's condition improved somewhat until the fifteenthday when generalized muscular twitching, irrationality,somnolence and pupillary inequality appeared. His neckwas held rigid, the deep reflexes were hyperactive, butBabinsky's sign was normal. Lumbar puncture revealedcloudy fluid under 18 mm. mercury pressure; 8 cc. werewithdrawn. Spinal drainage was repeated at intervals 10or 12 times thereafter. The patient voided involuntarilyand the stools were diarrhoeal for a day.

Irrationality and somnolence persisted with brief, ap-parently lucid intervals. On the seventeenth day he com-plained of severe pain in the left shoulder. His neckwas rigid and nystagmus was noted. He appeared to bemoribund on the eighteenth day, but thereafter graduallyimproved. On the twenty-fourth day two shaking chillsoccurred. At times he was irrational, but the tempera-ture gradually declined and remained normal after the

103102

10099

98-971

7 8 9 10 111213 14151617181920212223242526272293031323334355657 3839434742Dag OF diSease

FIG. 1. TEMPERATURECHARTOF PATIENT WITH M. tetragenus SEPTICEMIA,ARTHRITIS AND MENINGrIIS.

backache and pain in his limbs. Headache was severeand constant. There was transient earache and partialdeafness. After a day or two, pain localized in the rightknee, shoulder and arm. On several occasions thereafterthe backs of both hands became temporarily swollen andpainful. His condition remained unchanged until he en-tered the hospital on the seventh day of illness. Hispast history was irrelevant except for gonorrhea in 1931.

Physical examination revealed a moderately ill, febrilepatient evidently suffering from pain in his knee andshoulder. The pharyngitis had disappeared. There wastenderness and swelling of the right wrist, upper arm andshoulder, tenderness in the left shoulder, and the right

thirty-eighth day. The fever was remittent and ir-regular as shown in Figure 1. The pulse rate varied be-tween 70 and 110.

Laboratory observations. There was slight albumi-nuria. The leukocytes ranged between 12,000 and 18,000per cu. mm. The red cell count and hemoglobin wereunchanged. The blood Wassermann was negative. Thespinal fluid in the early period contained between 1400and 3400 cells, mostly polymorphonuclear neutrophils,between 8 and 40 mgm. sugar, and the Pandy and Nonnetests were positive. The cell count gradually diminishedto 21 on the sixty-fourth day when the last fluid waswithdrawn at which time 55 mgm. of sugar were present.

314

AMICROCOCCUST'ETRAGENUS INFECTION

BACTERIOLOGIC

Blood cultut-res. A bloodon the ninthl day showed grashaped cocci in sml-all clusteform after 24 hours at 3;tured on blood agar, a fesmall gramii-positive cocci vbe staphylococci grew in 2believed to be secondary invand were not studied furth(cultures in broth made on tteenth days were sterile, bplate two whitish coloniesThe colonies after a week atThe cocci composing eachof two distinct kinds, larg(occurred in tetrad formatioi

:S

AP BFIG. 2(A). LARGE AND SMALL

YELLOWCOLONYOBTAINED FROMTHE SIXTEENTH DAY OF ILLNEPLEOMORPHICCOCCI SURROUNDEDIN PUS FROMTHFE KNEE ASPIRAT](C) SMALL DIPLOCOCCI AND TOBTAINED FROM BROTH CULTURETHE FIFTEENTH DAY OF ILLNESS.

All magnified X 1150.

Pus froi11 the kniee. Inpus aspirated on the tenth d;positive, pleomorphic coccilonged search (Figure 2B)larger cocci were divided bThe clusters appeared to bestaining pink capsule-like n-agar plate inoculated with Icolony appeared composedmostly in tetrad formation.peared on plates streaked i

the eighteenth day. Cultuaspirated later were sterile.

Spinal flutid. Spinal flui(teenth day was inoculated in

STUDIES and on blood-agar plates. After 5 days incuba-

culture in broth mllade tion a slight stringy growth appeared at the bot-in-positive, irregularly tomii of 2 tubes. Smears from these culturesrs and a few in diplo- slhowed a few partly decolorized and some en-7° C. When subcul- tirely gram-negative cocci, irregular in shape andw minute colonies of size, mostly in tetrad formation. On subculturevhich were thought to from one tube on a blood-agar plate, 14 small24 hours. They were wlhite colonies appeared after 18 lhours, composedaders or contaminants of gram-positive smiiall tetrads. A halo sur-

er. Subsequent blood rounded the tetrads (Figure 2C) wlhiclh stuggestedhe sixteenth and nine- a capsule, but none was stained nor demonstrableut on one agar pour- with India ink. Organisms frolmi this colonyippeared after 3 days. were subcultured on blood-agar plates. After 48370 C. becamiie yellow. hours, large greenish colonies surrounded by a

of these colonies were green zone appeared. On several other blood-and small, and both agar plates, hemolysis was noted where the col-

n (Figure 2A). onies were crowded. On subculture on blood-agar or in blood-broth tubes hemolysis failed torecur. The colonies were composed of typicalgram-positive tetrads. Similar results were ob-tained from cultures of spinal fluiid obtained on

ps{t the eighteenth day. At this time, one large whitecolony appeared oIn a plain-agar plate after 48hours at 370 C. After centrifugation of a sam-

C ple removed on the twenty-seventh day, a fewdiplococci were seen for the first time in a direct

TETRADS COMPOSINGA smear. Thereafter, similar organisms were culti-A BLOOD CULTUREON vated from each of the subsequent samples of

BSSA (B) CLUSTERS OF spinal fluid by Dr. R. Koucky. The last culture

ED ON THE TENTH DAY. was obtained on August 20, three weeks afterETRADS (CAPSULATED?) the patient had become clinicallv well.E OF SPINAL FLUID ON Urethral puis. Pus expressed from the urethra

on two occasions showed a great predominanceof gram-positive cocci, arranged singly, in pairs,

a smear miade f rom in threes and many in tetrads and small clusters.

ay 3 clusters of gram- Cultures on plain-agar after 24 hours at 370 C.

were found after pro- formiied a heavy growth chiefly of whitish colonies

One or two of the composed of large gram-positive tetrads.y a transverse fissure. Rabbits, guinea pigs and white mice inoculated

enclosed in a faintly intraperitoneally with whole blood, spinal fluid,iaterial. On a blood- pus from the knee and with subcultures of thepus, one small whitish organism isolated fromii the three sources all sur-of gram-positive cocci vived. No agglutiniins for the organismii or any

Similar colonies ap- of its variant forms appeared in the patient'swith pus removed on blood obtained at 5 intervals during and after hisires made from pus illness. A dilute suspension of cocci killed by

heat at 600 C. for 1%, hour and injected intra-d obtained on the fif- cutaneously in the patient failed to cause ery-ito 3 plain-broth tubes thema. The general characteristics of the iso-

4

315

I

HOBARTA. REIJIANN

TABLE II

Cultural characteristics of M. tetragenus according to several authorities compared with the strain isolated from the case reported

Acid in

Atitlor Forim Coloniies on agar Growtli in brothi w C

Sterling, S., Centralbi. f. Capsuilated tetrads in Yellow, round + 0Bakt., 1896, 19, 141 blood ctulture

Leschke, E. (1) Tetrads, capsule present Greyish-wlhite, slimy. 0 + +in vivo and on solid Zone of hemolysismedia on blood-agar

Bergey, D. H., Mlantual of Tetrads in vivo, pairs or Whiite, smootlh, glis- Clear, gray se(imenit 0 A A A -4- 0 +Determinative Bacteri- irregular masses in me- teningology, Williams and dia, pseudocapsuleWilkins Co., Baltimore,1925, 2nd ed.

System of Bacteriology, Large capstulated tetrads Suirrouniided by greein Clotuding first then 0 Variable +Med. Res. Council, in vivo; smaller and area on l)lood-agar a depositLondon, 1929, 2, 26 single or pairs or groups

on media

Principles of Bacteriology Capstulated tetrads Gltutinouis, diffictult Tlhick, weedy gltuti- 0 A A A A +and Immunology, Top- to eimiulsify nous depositley, W. W. C., and Wil-son, G. S., Arnold, Lon-don, 1929, 1, 393

Textbook of Bacteriol- Capstilated tetradIs Transparent at first, Evenly clotuded 0 A +ogy, Zinsser, H., and later grayish-whiteBayne-Jones, S., Ap-pleton-Century Co.,New York, 1934, 7thied., p. 310

Thlis report WXVite colonies-large WhN'lite, occasionally Granular sedillelt. A) A A A 0 + () ()cocci in tetrads or in with greenish tinge Spirals on shlakinggroups. No capsule and halo on blood-

agarYellow colonies-large Yellow large Granuilar yellow sed- + in 0 0 0 0 0 0 0 0

cocci, usually all in tet- iment 3 wks.rads. No capsule

Translucent colonies- Smaller, yellow%-blue Diffuse with sedi- + in A A A 0 0 0 + 0cocci pleomorplhic, not iridescence mnent. Spirals on 2 daysin tetrads. No cap- shakingstole

lated micrococcus are summarized in the lowerportion of Table II.

Variaitioni of thc isol(tcd organiismnThe striking variations observed in the morpho-

logic characteristics of the cocci and of the coloniesat once suggested the oleration of dissociativephenomena. On one blood-culture agar-platethe colonies were composed of large and smallcocci (Figure 2A). \Nhen cocci from this colonvwere spread on another agar-plate, two types ofcolony appeared, large porcelain-like cream-col-ored colonies and a sparse growth of small whitecolonies (Figure 3B). An agar-plate seededfrom a large white colony was permitted to age

at room temperature. After 48 hours many ofthe isolated colonies became sulfur yellow whilethose crowded together renmainel smaller andwhite. After 5 days, opaque yellow " daughter"colonies appeared on somle of the large yellow

forms. On the twelfth day the colonies were alla golden yellow, and composed of large tetrads.A whitish halo appeared around some of thesmaller forms. On the halo, white " daughter"colonies grew and in the yellow center, yellow

daughter " colonies (Figure 3A) developed.\V7hen organisms from the small colonv were

seeded on agar, small opaque white colonies slowlyal)peared. The cocci were single, in diploform orin small clusters, pleomorphic and metachromatic(Figure 3E). WNhen the plate was examined witha 10 X hand lens after 72 hours, numerous minutetransparent colonies less than 0.1 mm. in diameterbecame visible scattered among the larger (1.5mm.) whitish ones. Cocci from these colonieswere markedly pleomorphic and many were com-l)letely decolorized by Gram's method. The coccivaried in size f rom those as large as the onesillustrated in Figure 3D to oines just within therange of vision of the oil imimersion system (Fig-

316

MICROCOCCUSTETRAGENUSINFECTION

41" SF~

FIG. 3(A). COLONIES 2 WEEKSOLD WHICHORIGINALLY WEREWHITE LIKE THOSEOF

B. After aging they became yellow and later developed a whitish halo-like outgrowth. Onthe yellow center are yellow " daughter " colonies, on the halo are white " daughter " colonies.(B) LARGEAND SMALL WHITE COLONIES. (C) LARGEAND SMALL TRANSLUCENTCOLONIES.(All slightly magnified.) (D) LARGECOCCI IN TETRADSCOMPOSINGTHE YELLOWCOLONIES.(E) SMALL COCCI SINGLE AND IN CLUSTERS COMPOSINGYOUNGWHITE COLONIES. (F)PLEOMORPHIC, METACHROMATICCOCCI COMPOSINGTHE TRANSLUCENTCOLONIES.

ure 3F). After 5 days incubation, the minutecolonies increas% 4 to 1 mm. in size and becametranslucent with a yellow-blue iridescence. Sub-culture produced colonies which grew more rapilyand were translucent. At various times duringsubsequent subcultures an occasional large whitecolony or a large yellow one would appear among

the myriads of translucent colonies.Thus from the blood culture at least three dis-

tinct, fairly stable forms of colony were obtained,(1) white, (2) yellow and (3) translucent.Other less stable varieties were observed. Bvspecial methods to be reported elsewhere, thetranslucent form was induced to dissociate into a

shell-pink variety and an orange-buff variety, eachof which bred true on repeated subculture. Therewas evidence of constant reversion of one forminto another. Similar results were observed withthe organism isolated from the spinal fluid andknee pus, and with several strains of M. tetragenusobtained from culture collections in Vienna andChicago.

The biological reactions of the organisms com-

posing the three varieties of colony varied con-

siderably as shown in Table II. Cocci from thewhite colonies were large, usually occurred inclusters or tetrads, produced greenish color on

blood-agar, did not liquefy gelatin, but fermenteddextrose, sucrose, maltose and lactose, and re-

duced potassium nitrate. Cocci from the yellowcolonies were in large and small tetrad formation,were chromogenic, liquefied gelatin slightly after3 weeks, did not ferment any sugar, or reducenitrate. Cocci from the translucent colonies were

markedly pleomorphic and rarely occurred intetrads; they liquefied gelatin in 2 days, fermenteddextrose, sucrose and maltose but not lactose, didnot reduce nitrate and were hemolytic. None ofthe strains fermented mannite, acidified milk nor

formed indol. None were pathogenic for mice.Capsules could never be demonstrated with cer-

tainty.

Classification, of thlc organism

Criteria for the identification of M. tetragenusvary considerably according to different authori-

*bi

D

317

38TOBARTA. REIJIANN

ties as a glance at Table II will reveal. No twocigree in all respects. In general, the organism issai(l to occur in large gram-positive, capsulatedtetrads in vivo and to become smiialler and lose1)oth capsule and tendency to group in fours onsubculture in vitro; the coloniies are glistening-wlhite; gelatin is not liquefied, milk is not co-agulated. blood cells are not hemolized, an(l nogas is produced in various sugar media. Thepoints of variance are the production of yellowand red pigment (Chauffard and Ramond (1),Sterling (2), Boschi and Bellei (13), Laignel-Lavastine and Baufle (1), Roger and Tremolieres(5), Brugnola (1, 8, 20, 21, 22) ; lack of virulencefor animals (Teissier, Boutron (22), Debove,Brugnola, Ziegler, KramAtr (1)); liquefaction ofgelatin (Sterling (15), Jacobelli (22). Chauffardand Ramond, Laignel-Lavastine and Baufle (1));coagulation of milk (Bergev, Zinsser an(d Bavne-Jones (15)); hemolvsis (Leschke (1)) and cap-sule formation (Bergey (15)).

Practicallv all of these apparent contradictionscan be explained on the basis of microbic dissocia-tion. Much confusion could have been avoidedhad the early studies of Boschi and Bellei (13)and Jacobelli (22) been more seriously considered.These observers anticipated the modern concep-tion of bacterial variation nearly 40 y-ears agowhen they showed that coloniies of Ill. tetra geniufs,aged on agar plates, formed yellow p)igment andthat after subsequent transfer, while coloniesagain appeared. Teissier (22) in 1896 evennoted the formation of " dauglhter " colonies.For a time it was controversial as to whethermany (lifferent strains existed or if the differentforms were all variants of a single strain. Itseemlls nlow that both views were correct; numer-ous strains exist and each may dissociate intovrarious forms.

There has been considerable difficulty in differ-entiating ll. tetragenius from the staphyloccus towhich it is closely related. The differences be-tween typical undissociated strains of either typeare distinct. The dissociated forms of one may,however, resemble either the undissociate(d formof the.other or its variants so closely that identifi-cationi is almost impossible, except if reversions tothe original form occur. For example, Hoffstadtan(l Youmans (23) have (lissociated the Staphylo-CoCctS aureus into n 1ll1lmler of variant forms,

some of which were no longer chromogenic, nolonger liquefied gelatini and no longer causedhemolvsis. These are reactionls also characteristicof A1l. tetragieiius. On the other hand, as I haveshown, one of the dissociated forms of 3l. tetr,a-genus liquefied gelatin. cause(l hemolvsis and itscocci grew in clusters and( p)roducedl colonies witha blue-yellow iri(lescence; it was thus in(listini-gTuishable from the staphylococcus except thatmilk was not acidified and( that occasionial rever-sions to the original form occurred.

COMMENT

Increased knowledge of microbic (lissociationhas explained many of the older difficulties in theclassification of bacteria. WNhen comp)aring onespecies of organisms with another it is necessaryto deal with known variants of each. As shownin this study, the " typical " undissociatedl formsof Ml. tetragenu ls andl S. aures are distinct.whereas the dissociated forms of one maylbe in-distinguishable from those of the other. Similarphenomena have been encountered in the study ofother bacteria. The relation of microbic dissocia-tion to infection, disease and recovery is but littleunderstood. It is of interest to speculate as to theform or phase or cyclostage in which Al. tetra-gen1u1s existe(l in the patient described in view ofthe fact that the organism was seen in its " atvl)i-cal ( ?) form in the pus from the knee andl spiinalfluid and because of its slow growth on first sub-culture ancd its presence in the spinal fluid afterthe patient ha(l a)pparently recovered. Furtherstudies in this regard and a dletailedl descriptionof the five variant forms will be presented else-where.

The isolation of a bacterium which grew incolonies of different character each composed ofcocci of different size, shape, arrangement andbiologic reactions from the same patient wouldlead one to suspect a mixed infection or con-tamination. It became evident that a single spe-cies with its variant forms was concerned afterthe transformation of one form of colony into an-other on culture media had been watched. It ispossible that cases of Al. tetragenus infection areoccasionallv missed because of the variability ofthe isolated organism, or without further studycases are easily mistaken for staphylococcus in-f ection .

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MICROCOCCUSTETRAGENUSINFECTION

SUMMARY

A nonfatal case of M. tetragenus infection withsepticemia, purulent arthritis and meningitis isdescribed. The organisms isolated from the pa-

tient's blood, pus from the knee and from thespinal fluid conformed in general to the criteriaestablished for the species Gaffkya tetragena.From the typical white colonies isolated, twovariant forms developed, one yellow, the othertranslucent; each form of colony was composedof cocci of different but constant characteristics.Reversion or transformation of one form into an-

other on culture media was observed. The bio-logic characteristics of the variant forms vary

considerably, which helps to explain the appar-

ently contradictory criteria of numerous authori-ties regarding the differentiation of M. tetragenusfrom staphylococci.

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