Acta Clinica Belgica International Journal of Clinical and Laboratory Medicine
ISSN: 1784-3286 (Print) 2295-3337 (Online) Journal homepage: http://www.tandfonline.com/loi/yacb20
Rapid Etiologic Diagnosis Of Bacterial Meningitis J.P. Butzler To cite this article: J.P. Butzler (1979) Rapid Etiologic Diagnosis Of Bacterial Meningitis, Acta Clinica Belgica, 34:2, 51-54, DOI: 10.1080/22953337.1979.11718668 To link to this article: http://dx.doi.org/10.1080/22953337.1979.11718668
Published online: 17 May 2016.
Submit your article to this journal
View related articles
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=yacb20 Download by: [Australian Catholic University]
Date: 04 August 2017, At: 06:20
51
RAPID ETIOLOGIC DIAGNOSIS OF BACTERIAL MENINGITIS
Downloaded by [Australian Catholic University] at 06:20 04 August 2017
J.P. Butzler*
Bacterial meningitis remains a life threatening infection despite the availability of effective antibiotics. If treatment is to be ucce ful, antibacterial therapy mu t be initiated before culture results become available. However the re ults of the cla ical examination of CSF may be inconclusive or totally misleading, especially in early bacterial meningitis. The examination of gram-stained mears of CSF for bacteria ha been hown to yield reliable information regarding the e tiological agent involved in only 60 to 80 % of ca e . The culture m e thod i somewh at low and often cumber ome and i not a lways productive. A number of new, rapid method ar b ecoming available to aid in th rapid diagnosi of meningiti . Th ese t t include : - nitroblue tetrazolium te - limulus I ate te t - creatinine phophokina e as ay - lac tic acid dchydrogena e - lactic acid oncentration - counter current immunoelectrophore i . Three of the c te t have been u ed with general su ce . The e arc the limu-
* Department
of Microbiolog Pieters Ho pita! Free University of Bru sel . t
!us lysate test, lactic acid in CSF and study of poly accharide antigens using counterimmunoelectrophore i . 1. -
LACTIC ACID IN THE CSF
Although it has been known for 50 years that CSF lactate is increa ed in ome ca e of bacterial meningitis, recent published reports (6, 13, 14) have hown the value of CSF lactate levels for the differential diagno i of bacterial, tuberculous or viral meningitis. It was ugge ted over 40 years ago that CSF lactic acid mea urements gave a more reliable index of the progre ion of infection than sugar content. Recently it ha b een hown that elevated lactic acid level came down within 72 hours of appropriate anti bacterial therapy. The explanation for increa ed concentration of lacti c a id in CSF during meningiti is far from being estab li shed. It has been sugge tcd that ome of kind " brain anemia» indu ced by increased intracranial pre sure disturbed brain irculation and resulted in incomplete oxygenation of th brain and formation of an exces of lactic acid after anaerobic glycolysi . Alt ration in metaboli m of white blood cells has been uggest d a its cau e, but in vitro experiment with leukocytes have only hown production of minute amount of lactic Acta Clinica Belgica, 34, 2 (1979)
Downloaded by [Australian Catholic University] at 06:20 04 August 2017
52
RAPID ETIOLOGIC DIAGNOSIS OF BACTERIAL MENINGITIS
acid. In some cases of non bacterial meningitis, normal concentrations of lactic acid were found in CSF despite the presence of many polymorphonuclear leukocytes. Bacterial metabolism could play a role in the production of lactic acid (17, 18, 19). However this hypothesis could not explain elevated lactic acid levels in the presence of non-viable bacteria in partially treated bacterial meningitis (13, 14 ). High concentrations of lactate have been found in other central nervous system diseases and in cases of brain anoxia induced by hypertensions. In these cases there were few leukocytes and no bacteria in the spinal fluid . It appears probable that brain hypoxia is the basis of the production of the excess CSF lactic acid found in cases of bacterial meningitis with possible contribution from leukocyte or bacterial metabolism.
lactic acid in differentiating tubercu lous from viral meningitis. CSF lactic acid increased in tuberculous meningitis and became normal only after several weeks of treatment. Here again, lactic acid was still elevated when complications occurred. Elevated CSF lactate levels have been reported in hypercapnia, hydrocephalus, brain abscesses, cerebral ischemia and in any clinical condition associated with reduced oxygenation of the brain and/or increased intracranial pressure. These conditions should be kept in mind when the lactate assay is interpreted. The finding of elevated lactate levels in bacterial meningitis is consistent with the hypothesis that inflammatory and edematous changes produce an accumulation of lactate that exceeds its rate of disposal.
Assays of CSF lactate have been done by two methods; gasliquid chromatography (6, 13, 14) and enzymatic spectrophotometry (U.V. lactate kit - Boehringer). Both methods give similar results and a level above 30 mg/100 ml is indicative of untreated or partially treated pyogenic, tuberculous or fungal meningitis. Levels below 30 mg/100 ml are found in later stages of treatment. In our experience (13, 14) a level of 35 mg/100 ml of CSF lactic acid differentiates bacterial from viral meningitis. In all cases of viral meningitis, a concentration below 35 mg/100 ml was found, while a concentration above 35 mg/100 ml was found in all cases of meningitis proven by culture, even in pretreated cases. When cases improved, the CSF lactate levels returned to normal while they remained elevated in patients without clinical improvement and in those where neurological signs per isted. Lactate levels at different stages of treatment offer a potentially useful indication of the efficacy of antibiotic therapy in bacterial meningi tis. Lauwers (13, 14) demonstrated the usefulness of
The « Limulus Lysate Test » is based on the property of endotoxins to induce a gelation of the lysate of circulating cells (amoebocytes) of the arthropod Limulus polyphemus (15). In 1973 R. Nachum ( 16) studied the test in the early diagnosis of gram-negative meningitis and demonstrated its effectiveness. The test is very easy to perform. One just has to mix the limulus amoebocytes ( commercialized as the Iysate form with an aliquot of CSF). Results are read after one hour of incubation at 37°C. The test may be considered as positive if a gel is formed. The limulus test is negative in meningitis cau ed by gram-positive microorganisms. This means that Streptococcal meningitis group B (an increasingly common type in the neonatal period) and Streptococcus pneumoniae meningitis, the only gram-positive meningitides occuring with any degree of frequency, will be undiagnosed with the Iimulus assay. American authors (1, 11, 16, 19) have reported positive results in more than 95 % of gram-negative meningitides. Furthermore, they did not describe ny
Acta Clinica Belgica, 34, 2 ( 1979)
2. -
THE LIMULUS LYSATE TEST
Downloaded by [Australian Catholic University] at 06:20 04 August 2017
RAPID ETIOLOGIC DIAGNOSIS OF BACTERIAL MENINGITIS
false positive reaction. Clumeck et al (3, 4) in a study of 64 patients had only one false negative and no false positive result. The concentration of bacteria in the CSF of patients with purulent meningitis have varied from 4.500 to 300 x 10 6 per ml. A false negative result may occur if the bacterial concentration is less than 500 per ml ( 11) . Such low bacterial concentrations may occur early in the disease as wa the case in the study of Clumeck, or when the patient had been treated before admission to the hospital (19). The limulus ly ate test is most useful when the gram stain is negative, since it might uggest a specific therapy which might otherwise only be considered after the result of cultures were known. Furthermore a repeat test a few days after the beginning of the treatment allows an eva lu ation of the therapy and may b e helpful if a relapse is suspected ( 4). 3. -
POLYSACCHARIDES IDENTIFIED BY COUNTER CURRENT IMMUNOELECTROPHORESIS (C.1.E.)
Some bacterial antigens, mostly polysaccharides, may be detected in body fluids because of their resistance to enzymatic destruction. In C.I.E., by passage of an electric current (2.5 v/cm) through the agar substrate at pH 8.2, antigens move into contact with specific antisera, and a precipitin line is formed. In practice a drop of patients CSF is studied using evera l antisera, usually those against N. meningitidis A, B, C and 135, S. pneumoniae and Haemophilus type B. For each anti erum a pair of wells i used. Reading can be made within I hour and can give an etiologic diagnosi within 1 hour after the receipt of the sample. The C.l.E. allow identification of a causal agent in a case of meningitis where previous treatment has killed microorgani ms invol ed in the infection, because chemotherapy has no influence in the
53
detection of antigens in body fluids. The u sefulness of the technique depends on the quality of antisera. The cell wall polysaccharides of S. pneumoniae, H. influenzae type B and N. meningitidis groups A and C can easi ly be detected . On the contrary the cell wall polysaccharides of N. meningitidis group B cannot easily be detected with the commercialized antiserum and N. meningitidis group B is the most frequently encountered serotype in Belgium. Feigin et al (10) have increased diagnostic efficiency by studying blood and urine in addition to CSF. Recently Beuvery et al (2) have demonstrated that an ELISA technique (Enzyme Linked Immunosorbent Assay) can also be u sed in the diagnosis of meningitis. Because of the serological cross-reactivity between cell wal antigens from bacteria causing meningitis, e.g. N. meningitis group B antigen and E. coli capsular poly accharide K 1 , the interpretation of som e positive findings requires also results of direct microscopy (5, 7, 8, 9, 10, 12) . Finally, a negative C.l.E. test performed on CSF can in no way rule out meningitis caused by organi ms for which the sample was tested. Ther fore, it is our feeling that the choice of initial antibiotic coverage should be based on results from clinical condition and CSF cell s, sugar, protein and mear analyses (9). Discontinuation or modification of therapy hould be ba ed primarily on the results of CSF culture and on C.l.E. finding only if they are positive. CONCLUSIONS Three simple rapidly performed tests are an important contribution to the diagnosi of bacterial meningitis. 1. - A CSF lactic level of more than 35 mg/100 ml sugg sts bacterial meningitis if hypercapnia, hydrocephalus, brain abscess, cerebra l i chemia and other conditions associated with lowered cerebral oxygenation are excluded. Acta Clinica Belgica, 34, 2 (1979)
RAPID ETIOLOGIC DIAGNOSIS OF BACTERIAL MENINGITIS
Downloaded by [Australian Catholic University] at 06:20 04 August 2017
54
2. - The limulus lysate tests of CSF is positive with gram-negative meningitis and gives rarely fal se negative results. The assay is negative with m eningitis caused by gram-positive microorganisms. Coun te rimmunoelec trophoresis 3. us ing a ntisera agains t b ac te rial cell wa ll a nti gens gives a r apid e tiologic diagnosis, but ca n give false n ega tive results, especially in the case o f N. menin gitis group B m eningiti s. Because of serologic cross reac tion s, the r esult must o ften b e interpre ted in association with the stained smear of the CSF. These three rapid diagnosti c tes ts are most u seful when e tiologic ambiguities s till remain after examination of the gram s tained smear. As with mos t diagn os tic techniqu es these assays a re r ecommended only to supplement exis ting s ta nd a rd laboratory evalua tion a nd physicia n clinical assessment. REFERE NCES . SIEGEL, S.S., NACHUM , R., LIPSEY A. and LEEDOM, J . (1976). Cerebros pin al fluid endotoxin co nce ntra tions in gra mn ega ti ve bac teri a l menin gitis. J. Ped., 88, 553. BEUVERY , E .C., VAN ROSSUM, F., LAUWERS, S. and COIGNAU , H . (1979) . Comparison of Counterimmunolec tropho res is a nd Elisa for di agnosis of Bac teri al Menin gitis. Lancet, i, 208. CLUMECK, N., LAUWERS, S. a nd BUTZLER, J .P. ( 1977). Limulus test a nd menin gitis. Br. Med. I., 1, 777. CLUMECK, N ., LAUWERS , S., KAHN, A., MOMMENS, M. et BUTZLER J.P. (1977) . Appo r t du tes t limule a u di agnos ti c des endotoxinemies et des m enin gites a gramnegatif. La Nouv. Pr. Med., 6, 1451. GOLDING, H . and LIND , J. (1977 ). Counte rimmunoelec tropho res is in the Di agn osis of Bacterial Menin gitis. J. Clinical Micro b., 5, 405. CONTRONI, G., RODRIGUEZ, W.J., DEANE, C., ROSS, S., KHAN, W., PUIG, J .R. (1975). Ra pid di agnosis of menin gitis by gas liquid chrom a togr a phic an alys is of cerebrospioal fluid lac tic aci d. Clin. Proc. Children's Hosp. Nat . Med. Center, 9, 194.
I. BERMAN, N .S.,
2.
3.
4.
5.
6.
Acta Clinica B elgica, 34, 2 (1979)
7. DEMOL, P. ( 1972) . Acquisitions r ecentes dans le diag nosti c p rccoce des menin gites bac teri enn es. Br. Med ., ii, 583. 8. DENIS, F., SAMB, A., CHIRON, J .P., SOW, A. et DIOP MAR, I., (1977) . Detecti on ra pide e t ident ifi ca ti on specifique des anti genes bacter iens par e lec tro-immunodiffusion dans 80 meningites pu rul entes . La Nouv. Pr. Med ., 6, 3391. 9. ECKFELDT, J ., MARY ED ERER, G., OETJ EN, R.N. ( 1978). Cou nter-i mmun oelec trop horesis a nd Bacteri al Menin gitis. I AMA, 239, 615. 10. FE IGIN , R., WONG, M., SHACKELFORD, P.G., STECHENBERG, B.W., DURKLE, L.M . and KAPLAN , S. ( 1976). Countercurrcn t imm unoelec trop horcsis of ur ine as well as of C.S.F. and blood for di agnos is of bac te ri a l meningitis. J. Ped ., 89, 773. i I. FELDMAN, W.E . (1976). Con ce nt ra ti ons of bacte ri a in cereb ros pinal flui.d o.f pa ti ents with bacte ri a l menin gitis. J. Ped., 88, 549. 12. GESLIN, P., LEGRAND, P., SQUINAXI, F . et HAUSDORF, M. (1977). Recherche d'antigenes bacterie ns solubles da ns dive rs produi ts pat hologi ques pa r contre-immunoelectropho rese. N ou v. Pr. Med., 6, 1853. 13. LAUWERS S. ( 1978). Lac ti c acid concentrati on in cerebrospi nal fluid a nd differe nti al di agn osi of menin gitis. Lancet, ii, 163. 14. LAUWERS, S. (1977) . Apport du do age d'acide lac tiqu e da ns le L.C.R. au dia gnostic di ffere nt iel des meningites . Acta Clin. B elg., 32, 319. JS. LEVIN, J., BANG, F.B. (1968). Clo.tta ble protei n in limulus : its localization and kin etics of its coagul a ti on by endotoxin. Tromb. Diat h. Haem orrh., 19, 186. 16. NACHUM, R., LIPSEY, A., SIEGEL, S.S. ( 1973 ). Ra pid detection of gra m-nega ti ve bacterial menin gitis by the limulus lysa te tes t. N. Engl. J. Med., 289, 931. 17. NISHIMURA, K. (1924) . The lac ti c ac id content of blood 'and pinal fluid . Proc. Soc. Exp. B iol. Med. 22, 322. 18. PAULSON, P.B. e t al. (1972). Cerebral blood fl ow, cerebra l meta bolic rate of oxygen and CSF ac id-base pa rameters in p a ti ents with acu te pyoge ni c meningitis and with acute enceph aliti s. Acta N eur. S cand., 48, 407. 19. ROSS, S., RODRIGUEZ, W., CONTRONI, G., KORENGOLD, G., WATSON, S., KHAN, W. ( 1975). Limulu s lysa te tes t for gram-nega tive bac terial meningitis. J. Am. Med. Assoc. 233, 1366. 20. SUDRE, Y .. REISS, D. (1969) . Intere t du dosage de l'acide lactique du L.C.R. dans Jes meningites. Bordeaux Medical, 10, 2045.
ISSN: 1784-3286 (Print) 2295-3337 (Online) Journal homepage: http://www.tandfonline.com/loi/yacb20
Rapid Etiologic Diagnosis Of Bacterial Meningitis J.P. Butzler To cite this article: J.P. Butzler (1979) Rapid Etiologic Diagnosis Of Bacterial Meningitis, Acta Clinica Belgica, 34:2, 51-54, DOI: 10.1080/22953337.1979.11718668 To link to this article: http://dx.doi.org/10.1080/22953337.1979.11718668
Published online: 17 May 2016.
Submit your article to this journal
View related articles
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=yacb20 Download by: [Australian Catholic University]
Date: 04 August 2017, At: 06:20
51
RAPID ETIOLOGIC DIAGNOSIS OF BACTERIAL MENINGITIS
Downloaded by [Australian Catholic University] at 06:20 04 August 2017
J.P. Butzler*
Bacterial meningitis remains a life threatening infection despite the availability of effective antibiotics. If treatment is to be ucce ful, antibacterial therapy mu t be initiated before culture results become available. However the re ults of the cla ical examination of CSF may be inconclusive or totally misleading, especially in early bacterial meningitis. The examination of gram-stained mears of CSF for bacteria ha been hown to yield reliable information regarding the e tiological agent involved in only 60 to 80 % of ca e . The culture m e thod i somewh at low and often cumber ome and i not a lways productive. A number of new, rapid method ar b ecoming available to aid in th rapid diagnosi of meningiti . Th ese t t include : - nitroblue tetrazolium te - limulus I ate te t - creatinine phophokina e as ay - lac tic acid dchydrogena e - lactic acid oncentration - counter current immunoelectrophore i . Three of the c te t have been u ed with general su ce . The e arc the limu-
* Department
of Microbiolog Pieters Ho pita! Free University of Bru sel . t
!us lysate test, lactic acid in CSF and study of poly accharide antigens using counterimmunoelectrophore i . 1. -
LACTIC ACID IN THE CSF
Although it has been known for 50 years that CSF lactate is increa ed in ome ca e of bacterial meningitis, recent published reports (6, 13, 14) have hown the value of CSF lactate levels for the differential diagno i of bacterial, tuberculous or viral meningitis. It was ugge ted over 40 years ago that CSF lactic acid mea urements gave a more reliable index of the progre ion of infection than sugar content. Recently it ha b een hown that elevated lactic acid level came down within 72 hours of appropriate anti bacterial therapy. The explanation for increa ed concentration of lacti c a id in CSF during meningiti is far from being estab li shed. It has been sugge tcd that ome of kind " brain anemia» indu ced by increased intracranial pre sure disturbed brain irculation and resulted in incomplete oxygenation of th brain and formation of an exces of lactic acid after anaerobic glycolysi . Alt ration in metaboli m of white blood cells has been uggest d a its cau e, but in vitro experiment with leukocytes have only hown production of minute amount of lactic Acta Clinica Belgica, 34, 2 (1979)
Downloaded by [Australian Catholic University] at 06:20 04 August 2017
52
RAPID ETIOLOGIC DIAGNOSIS OF BACTERIAL MENINGITIS
acid. In some cases of non bacterial meningitis, normal concentrations of lactic acid were found in CSF despite the presence of many polymorphonuclear leukocytes. Bacterial metabolism could play a role in the production of lactic acid (17, 18, 19). However this hypothesis could not explain elevated lactic acid levels in the presence of non-viable bacteria in partially treated bacterial meningitis (13, 14 ). High concentrations of lactate have been found in other central nervous system diseases and in cases of brain anoxia induced by hypertensions. In these cases there were few leukocytes and no bacteria in the spinal fluid . It appears probable that brain hypoxia is the basis of the production of the excess CSF lactic acid found in cases of bacterial meningitis with possible contribution from leukocyte or bacterial metabolism.
lactic acid in differentiating tubercu lous from viral meningitis. CSF lactic acid increased in tuberculous meningitis and became normal only after several weeks of treatment. Here again, lactic acid was still elevated when complications occurred. Elevated CSF lactate levels have been reported in hypercapnia, hydrocephalus, brain abscesses, cerebral ischemia and in any clinical condition associated with reduced oxygenation of the brain and/or increased intracranial pressure. These conditions should be kept in mind when the lactate assay is interpreted. The finding of elevated lactate levels in bacterial meningitis is consistent with the hypothesis that inflammatory and edematous changes produce an accumulation of lactate that exceeds its rate of disposal.
Assays of CSF lactate have been done by two methods; gasliquid chromatography (6, 13, 14) and enzymatic spectrophotometry (U.V. lactate kit - Boehringer). Both methods give similar results and a level above 30 mg/100 ml is indicative of untreated or partially treated pyogenic, tuberculous or fungal meningitis. Levels below 30 mg/100 ml are found in later stages of treatment. In our experience (13, 14) a level of 35 mg/100 ml of CSF lactic acid differentiates bacterial from viral meningitis. In all cases of viral meningitis, a concentration below 35 mg/100 ml was found, while a concentration above 35 mg/100 ml was found in all cases of meningitis proven by culture, even in pretreated cases. When cases improved, the CSF lactate levels returned to normal while they remained elevated in patients without clinical improvement and in those where neurological signs per isted. Lactate levels at different stages of treatment offer a potentially useful indication of the efficacy of antibiotic therapy in bacterial meningi tis. Lauwers (13, 14) demonstrated the usefulness of
The « Limulus Lysate Test » is based on the property of endotoxins to induce a gelation of the lysate of circulating cells (amoebocytes) of the arthropod Limulus polyphemus (15). In 1973 R. Nachum ( 16) studied the test in the early diagnosis of gram-negative meningitis and demonstrated its effectiveness. The test is very easy to perform. One just has to mix the limulus amoebocytes ( commercialized as the Iysate form with an aliquot of CSF). Results are read after one hour of incubation at 37°C. The test may be considered as positive if a gel is formed. The limulus test is negative in meningitis cau ed by gram-positive microorganisms. This means that Streptococcal meningitis group B (an increasingly common type in the neonatal period) and Streptococcus pneumoniae meningitis, the only gram-positive meningitides occuring with any degree of frequency, will be undiagnosed with the Iimulus assay. American authors (1, 11, 16, 19) have reported positive results in more than 95 % of gram-negative meningitides. Furthermore, they did not describe ny
Acta Clinica Belgica, 34, 2 ( 1979)
2. -
THE LIMULUS LYSATE TEST
Downloaded by [Australian Catholic University] at 06:20 04 August 2017
RAPID ETIOLOGIC DIAGNOSIS OF BACTERIAL MENINGITIS
false positive reaction. Clumeck et al (3, 4) in a study of 64 patients had only one false negative and no false positive result. The concentration of bacteria in the CSF of patients with purulent meningitis have varied from 4.500 to 300 x 10 6 per ml. A false negative result may occur if the bacterial concentration is less than 500 per ml ( 11) . Such low bacterial concentrations may occur early in the disease as wa the case in the study of Clumeck, or when the patient had been treated before admission to the hospital (19). The limulus ly ate test is most useful when the gram stain is negative, since it might uggest a specific therapy which might otherwise only be considered after the result of cultures were known. Furthermore a repeat test a few days after the beginning of the treatment allows an eva lu ation of the therapy and may b e helpful if a relapse is suspected ( 4). 3. -
POLYSACCHARIDES IDENTIFIED BY COUNTER CURRENT IMMUNOELECTROPHORESIS (C.1.E.)
Some bacterial antigens, mostly polysaccharides, may be detected in body fluids because of their resistance to enzymatic destruction. In C.I.E., by passage of an electric current (2.5 v/cm) through the agar substrate at pH 8.2, antigens move into contact with specific antisera, and a precipitin line is formed. In practice a drop of patients CSF is studied using evera l antisera, usually those against N. meningitidis A, B, C and 135, S. pneumoniae and Haemophilus type B. For each anti erum a pair of wells i used. Reading can be made within I hour and can give an etiologic diagnosi within 1 hour after the receipt of the sample. The C.l.E. allow identification of a causal agent in a case of meningitis where previous treatment has killed microorgani ms invol ed in the infection, because chemotherapy has no influence in the
53
detection of antigens in body fluids. The u sefulness of the technique depends on the quality of antisera. The cell wall polysaccharides of S. pneumoniae, H. influenzae type B and N. meningitidis groups A and C can easi ly be detected . On the contrary the cell wall polysaccharides of N. meningitidis group B cannot easily be detected with the commercialized antiserum and N. meningitidis group B is the most frequently encountered serotype in Belgium. Feigin et al (10) have increased diagnostic efficiency by studying blood and urine in addition to CSF. Recently Beuvery et al (2) have demonstrated that an ELISA technique (Enzyme Linked Immunosorbent Assay) can also be u sed in the diagnosis of meningitis. Because of the serological cross-reactivity between cell wal antigens from bacteria causing meningitis, e.g. N. meningitis group B antigen and E. coli capsular poly accharide K 1 , the interpretation of som e positive findings requires also results of direct microscopy (5, 7, 8, 9, 10, 12) . Finally, a negative C.l.E. test performed on CSF can in no way rule out meningitis caused by organi ms for which the sample was tested. Ther fore, it is our feeling that the choice of initial antibiotic coverage should be based on results from clinical condition and CSF cell s, sugar, protein and mear analyses (9). Discontinuation or modification of therapy hould be ba ed primarily on the results of CSF culture and on C.l.E. finding only if they are positive. CONCLUSIONS Three simple rapidly performed tests are an important contribution to the diagnosi of bacterial meningitis. 1. - A CSF lactic level of more than 35 mg/100 ml sugg sts bacterial meningitis if hypercapnia, hydrocephalus, brain abscess, cerebra l i chemia and other conditions associated with lowered cerebral oxygenation are excluded. Acta Clinica Belgica, 34, 2 (1979)
RAPID ETIOLOGIC DIAGNOSIS OF BACTERIAL MENINGITIS
Downloaded by [Australian Catholic University] at 06:20 04 August 2017
54
2. - The limulus lysate tests of CSF is positive with gram-negative meningitis and gives rarely fal se negative results. The assay is negative with m eningitis caused by gram-positive microorganisms. Coun te rimmunoelec trophoresis 3. us ing a ntisera agains t b ac te rial cell wa ll a nti gens gives a r apid e tiologic diagnosis, but ca n give false n ega tive results, especially in the case o f N. menin gitis group B m eningiti s. Because of serologic cross reac tion s, the r esult must o ften b e interpre ted in association with the stained smear of the CSF. These three rapid diagnosti c tes ts are most u seful when e tiologic ambiguities s till remain after examination of the gram s tained smear. As with mos t diagn os tic techniqu es these assays a re r ecommended only to supplement exis ting s ta nd a rd laboratory evalua tion a nd physicia n clinical assessment. REFERE NCES . SIEGEL, S.S., NACHUM , R., LIPSEY A. and LEEDOM, J . (1976). Cerebros pin al fluid endotoxin co nce ntra tions in gra mn ega ti ve bac teri a l menin gitis. J. Ped., 88, 553. BEUVERY , E .C., VAN ROSSUM, F., LAUWERS, S. and COIGNAU , H . (1979) . Comparison of Counterimmunolec tropho res is a nd Elisa for di agnosis of Bac teri al Menin gitis. Lancet, i, 208. CLUMECK, N., LAUWERS, S. a nd BUTZLER, J .P. ( 1977). Limulus test a nd menin gitis. Br. Med. I., 1, 777. CLUMECK, N ., LAUWERS , S., KAHN, A., MOMMENS, M. et BUTZLER J.P. (1977) . Appo r t du tes t limule a u di agnos ti c des endotoxinemies et des m enin gites a gramnegatif. La Nouv. Pr. Med., 6, 1451. GOLDING, H . and LIND , J. (1977 ). Counte rimmunoelec tropho res is in the Di agn osis of Bacterial Menin gitis. J. Clinical Micro b., 5, 405. CONTRONI, G., RODRIGUEZ, W.J., DEANE, C., ROSS, S., KHAN, W., PUIG, J .R. (1975). Ra pid di agnosis of menin gitis by gas liquid chrom a togr a phic an alys is of cerebrospioal fluid lac tic aci d. Clin. Proc. Children's Hosp. Nat . Med. Center, 9, 194.
I. BERMAN, N .S.,
2.
3.
4.
5.
6.
Acta Clinica B elgica, 34, 2 (1979)
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