11

BRUCELLOSISBRUCELLOSIS

22

Introduction & History

Brucellosis: Disease of domestic and wild animals Brucellosis: Disease of domestic and wild animals (zoonosis): Transmittable to humans. It has different (zoonosis): Transmittable to humans. It has different non-specific symptoms and signs “No disease, not non-specific symptoms and signs “No disease, not excepting tuberculosis and syphilis, is more protean excepting tuberculosis and syphilis, is more protean in its manifestations”..(Simpson).in its manifestations”..(Simpson).

Marston – Surgeon serving with Royal Artillery Marston – Surgeon serving with Royal Artillery during Crimean war-reported first accurate during Crimean war-reported first accurate description of human brucellosis.description of human brucellosis.

1886, Bruce isolated Micrococcus (later Brucella) 1886, Bruce isolated Micrococcus (later Brucella) Melitensis from spleens of malta fever victimsMelitensis from spleens of malta fever victims.

33

Introduction and History (Cont’d.)Introduction and History (Cont’d.) Zamit – maltese physician, identified native goats Zamit – maltese physician, identified native goats

as infection reservoir, during his work with as infection reservoir, during his work with Mediterranean fever commission 1904-1907. He Mediterranean fever commission 1904-1907. He also identified fresh goat’s milk as vehicle of also identified fresh goat’s milk as vehicle of transmitting disease from animals to humanstransmitting disease from animals to humans..

1895, Bang (Danish Veterinarian) identified 1895, Bang (Danish Veterinarian) identified Bacillus (later Brucella) abortus as cause of Bacillus (later Brucella) abortus as cause of contagious abortions in cattle. contagious abortions in cattle.

Evans (American bacteriologist) recognized Evans (American bacteriologist) recognized relation of Malta fever agent and Bang’s diseaserelation of Malta fever agent and Bang’s disease

44

Introduction and History (Cont’d.)Introduction and History (Cont’d.) Genus – Bacillus, micrococcus, causing Malta Genus – Bacillus, micrococcus, causing Malta

fever, renamed Brucella, to honor Bruce.fever, renamed Brucella, to honor Bruce. Traum, 1914, isolated Brucella Canis, from Traum, 1914, isolated Brucella Canis, from

aborted Kennel-bred dogs.aborted Kennel-bred dogs. Carmichael, 1966, isolated Brucella Canis, from Carmichael, 1966, isolated Brucella Canis, from

aborted Kennel-bred dogs.aborted Kennel-bred dogs. Brucella ovis from sheep and Brucella neotomae Brucella ovis from sheep and Brucella neotomae

from desert wood rats, added to Brucella species, from desert wood rats, added to Brucella species, but to date these two not shown to cause human but to date these two not shown to cause human infections.infections.

55

Introduction and History (cont’d.)Introduction and History (cont’d.)

1994, British and American workers, independ-1994, British and American workers, independ-

ently, isolated previuously unknown Brucellaently, isolated previuously unknown Brucella

organism from carcasses of marine mammals andorganism from carcasses of marine mammals and

cetaceans on Scotland coast, and from dolphin incetaceans on Scotland coast, and from dolphin in

California. These isolates-homogenous with California. These isolates-homogenous with

distinctive metabolic, sensitivities to dye, phagedistinctive metabolic, sensitivities to dye, phage

sensitivity-tentatively named Brucella Maris.sensitivity-tentatively named Brucella Maris.

66

THE PATHOGENTHE PATHOGEN Brucellae: Small, GN cocobacilli, non-motile, non-Brucellae: Small, GN cocobacilli, non-motile, non-

spore forming.spore forming. Brucellae grow aerobically.Brucellae grow aerobically. Some spp. Require supplemental carbon dioxide Some spp. Require supplemental carbon dioxide

for primary isolation.for primary isolation. Any high-quality peptone-based media enriched Any high-quality peptone-based media enriched

with blood or serum serve for in vitro cultivation.with blood or serum serve for in vitro cultivation. Isolation form clinical specimens require prolonged Isolation form clinical specimens require prolonged

(≥ 30 days) incubation.(≥ 30 days) incubation. Brucella strains always catalse-positive; but Brucella strains always catalse-positive; but

oxidase and urease and Hoxidase and urease and H22S production vary.S production vary.

77

The Pathogen (cont’d.)The Pathogen (cont’d.) Major Brucellae species and their biovars Major Brucellae species and their biovars

differentiated by selective inhibition of growth on differentiated by selective inhibition of growth on media containing dyes-e.g. Thionin and basic media containing dyes-e.g. Thionin and basic fuchsin.fuchsin.

Genus Brucella divided into six (possibly seven) Genus Brucella divided into six (possibly seven) nomen spp. on basis of preferred hosts and nomen spp. on basis of preferred hosts and cultural, metabolic and antigenic characteristics.cultural, metabolic and antigenic characteristics.

DNA-DNA hybridization studies shown DNA-DNA hybridization studies shown remarkable( >95%) homology between strains, remarkable( >95%) homology between strains, suggesting mono-specific gems with subspecies suggesting mono-specific gems with subspecies corresponding evolutionary lineage adapted to corresponding evolutionary lineage adapted to specific hosts.specific hosts.

88

The Pathogen (cont’d.)The Pathogen (cont’d.) Wilson and Miles, first described major cell wall Wilson and Miles, first described major cell wall

antigen and virulence factor of brucellae to be S-antigen and virulence factor of brucellae to be S-Lps containing A and M antigens.Lps containing A and M antigens.

Presence of 4-amino, 4,6 dideoxymannose in Lps Presence of 4-amino, 4,6 dideoxymannose in Lps is responsible for antigenic cross-reaction with is responsible for antigenic cross-reaction with other G.N.B. e.g. - vibrio cholerae 01 and Yersinia other G.N.B. e.g. - vibrio cholerae 01 and Yersinia 09.09.

Numerous protein antigens maybe important in Numerous protein antigens maybe important in inducing protective immunityinducing protective immunity..

99

EpidemiologyEpidemiology Brucellosis – zoonosis – all infections, derive Brucellosis – zoonosis – all infections, derive

directly or indirectly from animals exposure.directly or indirectly from animals exposure. Disease exists world-wide, esp. Mediterranean, Disease exists world-wide, esp. Mediterranean,

Arabic Peninsula, Indian subcontinent, parts of Arabic Peninsula, Indian subcontinent, parts of Mexico and Central South America.Mexico and Central South America.

B. abortus found mainly in cattle, but others spp. B. abortus found mainly in cattle, but others spp. like buffalo, camels, tales can be affected.like buffalo, camels, tales can be affected.

B. Melitensis primary affects goats and sheep. B. Melitensis primary affects goats and sheep. Camels can be important source in some Camels can be important source in some countries.countries.

B. Suis biovars 1-3 in domestic and feral swine, B. Suis biovars 1-3 in domestic and feral swine, cause abattoir-assoc. human disease.cause abattoir-assoc. human disease.

1010

Epidemiology (Cont’d.)Epidemiology (Cont’d.) B. Canis: Least common cause of human B. Canis: Least common cause of human

disease.disease. Animals: Brucellosis, Ch. Infection, persisting for Animals: Brucellosis, Ch. Infection, persisting for

life.life. Brucellae localization in reproductive organs, Brucellae localization in reproductive organs,

accounts for major manifestations – abortion and accounts for major manifestations – abortion and sterility.sterility.

Brucellae shed in large numbers in: Milk, urine, Brucellae shed in large numbers in: Milk, urine, cyetic products of infected animals.cyetic products of infected animals.

1111

Epidemiology (Cont’d.)Epidemiology (Cont’d.) Thus, Brucellosis constitutes occupational risk for: Thus, Brucellosis constitutes occupational risk for:

farmers, veterinarians, abattoirs and Laboratory farmers, veterinarians, abattoirs and Laboratory personnel.personnel.

Routes of transmission to human include:Routes of transmission to human include:

- Director contact with animals or their secretions,- Director contact with animals or their secretions,

through cuts and skin abrasions.through cuts and skin abrasions.

- Infected aerosols inhaled or inoculated into eye- Infected aerosols inhaled or inoculated into eye

conjunctival sac.conjunctival sac.

- Ingestion of unpasteurized dairy products.- Ingestion of unpasteurized dairy products.

1212

EpidemiologyEpidemiology (Cont’d.) (Cont’d.)- Meat products: rare source of infection- Meat products: rare source of infection

because: Meat is rarely eaten raw andbecause: Meat is rarely eaten raw and organisms are present in low number oforganisms are present in low number of

muscle tissue.muscle tissue. - Blood and bone marrow may transmit- Blood and bone marrow may transmit disease when ingested in some cultures.disease when ingested in some cultures. - Human-to-human transmission: Unusual, but- Human-to-human transmission: Unusual, but rare cases suspected to be sexuallyrare cases suspected to be sexually transmitted.transmitted.

1313

Epidemiology (cont’d.)Epidemiology (cont’d.)- One case reported recently, presumptively due- One case reported recently, presumptively due

to intra-uterine transmissionto intra-uterine transmission.. Aids patient, prone to infections by zoonoses, but Aids patient, prone to infections by zoonoses, but

Brucellosis occurred in very few of these patients.Brucellosis occurred in very few of these patients. If CDIf CD44 not severely depressed, course of not severely depressed, course of

brucellosis in Aids pts. not different from disease in brucellosis in Aids pts. not different from disease in immunocompetent pts.immunocompetent pts.

Brucellosis not rare in children as previously Brucellosis not rare in children as previously believed.believed.

Brucellosis manifests similarly in: Neonates, Brucellosis manifests similarly in: Neonates, children and adults.children and adults.

1414

PathogenesisPathogenesis B. melitensis and B. suis, more virulent than B. B. melitensis and B. suis, more virulent than B.

abortus and B. canis.abortus and B. canis. Infection with any B. species, including attenuated Infection with any B. species, including attenuated

vaccine strains can cause serious human disease.vaccine strains can cause serious human disease. Disease determined by:Disease determined by:

- Host nutritional and immune status.- Host nutritional and immune status.- Size of infectious inoculum.- Size of infectious inoculum.- Route of transmission.- Route of transmission.

Ex: -Low gastric juice PH, more effective inEx: -Low gastric juice PH, more effective in preventing B. abortus than B. melitensispreventing B. abortus than B. melitensis infection when administered by oral routeinfection when administered by oral route ..

1515

Pathogenesis (cont’d.)Pathogenesis (cont’d.)-Therefore, drugs that decrease gastric-Therefore, drugs that decrease gastric

acidity were implicated in food borneacidity were implicated in food borne

brucellosis.brucellosis. Once brucellae gain entry to body: PMN – Once brucellae gain entry to body: PMN –

Leukocytes attracted to inoculation site by Leukocytes attracted to inoculation site by chemotaxis.chemotaxis.

Normal human serum has limited bactericidal Normal human serum has limited bactericidal activity against brucellae, but it effectively activity against brucellae, but it effectively opsonizes bacteria for phagocytosis by PMN – opsonizes bacteria for phagocytosis by PMN – LeukocytesLeukocytes..

1616

Pathogenesis (cont’d.)Pathogenesis (cont’d.) Brucellae: Facultative intracellular, slowly dividing Brucellae: Facultative intracellular, slowly dividing

pathogens with capacity to survive and multiply pathogens with capacity to survive and multiply within host phagocytic cells.within host phagocytic cells.

Mechanism by which brucellae evade intracellular Mechanism by which brucellae evade intracellular killing by PMN-Leukocytes incompletely under-killing by PMN-Leukocytes incompletely under-stood, it is possible that bacteria property enable stood, it is possible that bacteria property enable themthem to escape detection.to escape detection.

Factors contributing to intracellular survival:Factors contributing to intracellular survival:- Production of adenine and guanine monophos-- Production of adenine and guanine monophos-

phate.phate.

1717

Pathogenesis (cont’d.)Pathogenesis (cont’d.)-These suppress myeloperoxide – H-These suppress myeloperoxide – H22OO22-halide-halide

system and cu-zn superoxide dismutase, whichsystem and cu-zn superoxide dismutase, which eliminates reactive oxygen intermediates.eliminates reactive oxygen intermediates. Spink compared brucellosis with typhoid fever Spink compared brucellosis with typhoid fever

because bacteria enter lymphatic and replicate because bacteria enter lymphatic and replicate within regional lymph nodes.within regional lymph nodes.

Hematogenous dissemination then followed by Hematogenous dissemination then followed by localization of bacteria within organs richlocalization of bacteria within organs rich in in reticuloendothelial system, e.g. liver, spleen and reticuloendothelial system, e.g. liver, spleen and B. marrow.B. marrow.

1818

Pathogenesis (Cont’d.)Pathogenesis (Cont’d.) Brucellae ingested by mononuclear phagocytes Brucellae ingested by mononuclear phagocytes

survive and replicate initially. Intracellular survival survive and replicate initially. Intracellular survival within macrophages facilitated by inhibition of within macrophages facilitated by inhibition of phagoxome-Lysosome fusion by soluble products phagoxome-Lysosome fusion by soluble products of brucellae, and production of stress-induced of brucellae, and production of stress-induced proteins.proteins.

Eventual elimination of virulent brucellae depends Eventual elimination of virulent brucellae depends on activation of macrophages through develop-on activation of macrophages through develop-ment of Th-1type cell-mediated immunity.ment of Th-1type cell-mediated immunity.

Cytokines contributing to anti-brucella activity of Cytokines contributing to anti-brucella activity of activated macrophages include: TNF-alpha, TNF-activated macrophages include: TNF-alpha, TNF-gamma, IL-1, IL-12.gamma, IL-1, IL-12.

1919

Pathogenesis (cont’d.)Pathogenesis (cont’d.) Major determinant of virulence and immuno-Major determinant of virulence and immuno-

dominant antigen of Brucella is S-Lps.dominant antigen of Brucella is S-Lps. Growth of B. abortus in cattle placental tissue Growth of B. abortus in cattle placental tissue

apparently enhanced by eruthritol, this may apparently enhanced by eruthritol, this may explain localization of brucellae in genital tracts of explain localization of brucellae in genital tracts of ungulates.ungulates.

2020

HOST IMMUNITYHOST IMMUNITY Genetic studies in various animals showed that Genetic studies in various animals showed that

resistance to intracellular pathogens is polygenic; resistance to intracellular pathogens is polygenic; but single genes recognized to have major effect on but single genes recognized to have major effect on immune-mediated resistance. Selected breeding of immune-mediated resistance. Selected breeding of cattle yielded evidence for genetic determination of cattle yielded evidence for genetic determination of resistance to bovine brucellosis.resistance to bovine brucellosis.

Data suggested that resistance reflected in Data suggested that resistance reflected in immunoglobulin allotypes and in difference in ability immunoglobulin allotypes and in difference in ability of macrophages to control B. abortus replication in of macrophages to control B. abortus replication in

vitrovitro..

2121

Host Immunity (Cont’d.)Host Immunity (Cont’d.) S-Lps is major deter of virulence of brucellae and S-Lps is major deter of virulence of brucellae and

dominates antibody response. Humoral anti-dominates antibody response. Humoral anti-bodies to S-Lps confer short-term protection as bodies to S-Lps confer short-term protection as shown by passive transfer experiments using shown by passive transfer experiments using monoclonal and polyclonal antibodies. Antibodies monoclonal and polyclonal antibodies. Antibodies to S-Lps used for diagnosis when bacterial to S-Lps used for diagnosis when bacterial isolation is unsuccessful.isolation is unsuccessful.

Variety of serologic tests used to measure anti-Variety of serologic tests used to measure anti-bodies to brucellae. Earliest was serum agglutina-bodies to brucellae. Earliest was serum agglutina-tion test (SAT), devised by Wright and Smith 1897.tion test (SAT), devised by Wright and Smith 1897.

SAT. Measures total quantity of agglutinating anti-SAT. Measures total quantity of agglutinating anti-bodies, but does not distinguish between immuno-bodies, but does not distinguish between immuno-globulin isotypes.globulin isotypes.

2222

HOST IMMUNITYHOST IMMUNITY (Cont’d.) (Cont’d.) In time, IgM antibodies titers decline, and with

treatment IgG antibodies titers fall consistent with recovery.

Failure of IgG titer to decline is prognostic of relapse or chronic infection.

Currently, there is interest in cytoplasmic protein antigens in both smooth and rough strains, which could be used for diagnostic purposes.

Reddin and colleagues modified SAT, by adding 2-mercapto-ethanol(2ME) to differentiate agglutina-tion by IgG-antibodies, and showed that IG antibodies correlated well with active infection.

2323

Host Immunity (cont’d.)Host Immunity (cont’d.) Combination of SAT and 2 ME test shown to be Combination of SAT and 2 ME test shown to be

useful to monitor Brucellosis course and response useful to monitor Brucellosis course and response to therapy.to therapy.

Application of enzyme-linked immunoabsorbent Application of enzyme-linked immunoabsorbent assay (ELISA) measures immune response to assay (ELISA) measures immune response to therapy.therapy.

IgM antibodies appear within 1IgM antibodies appear within 1stst week of infection week of infection and followed by switch to IgG synthesis after 2and followed by switch to IgG synthesis after 2ndnd week.week.

In time, IgM antibodies titers decline and with treat- In time, IgM antibodies titers decline and with treat- ment IgG antibodies, titers fall consistent with ment IgG antibodies, titers fall consistent with recovery.recovery.

2424

Host Immunity (cont’d.)Host Immunity (cont’d.)

Failure of IgG titer to decline is prognostic of Failure of IgG titer to decline is prognostic of relapse or chronic infection.relapse or chronic infection.

Currently, there is interest in cytoplasmic protein Currently, there is interest in cytoplasmic protein antigens in both smooth and rough strains, which antigens in both smooth and rough strains, which could be used for diagnostic purposes.could be used for diagnostic purposes.

2525

Clinical Manifestation Symptoms of Brucellosis: non-specific, e.g. fever,

sweats, malaise, anorexia, headache, backpain. Onset: acute or insidious, beginning within 2 to 4

weeks after inoculation. An “Undulant” fever pattern observed if patients go

untreated for long periods. Some patients c/o malodorous sweat and peculiar

mouth taste. Depression common and often out of proportion to

severity of symptoms. In comparison to plethora of somatic complaints,

physical abnormalities are few. Mild lymphadenopathy reported in 10 to 20% of

cases.

2626

Clinical Manifestation Splenomegaly or hepatomegaly in 20 to 30% of Splenomegaly or hepatomegaly in 20 to 30% of

cases.cases. Brucellosis: systemic infection in which any organ Brucellosis: systemic infection in which any organ

or system of the body can be involved.or system of the body can be involved. Attempts to categorize the disease into acute, Attempts to categorize the disease into acute,

subacute and chronic, according to symptoms, subacute and chronic, according to symptoms, length and severity are purely arbitrary.length and severity are purely arbitrary.

Disease referred to focal or localized when Disease referred to focal or localized when involvement of specific organ predominates. involvement of specific organ predominates. However, there is little evidence that such However, there is little evidence that such complication representcomplication represent distinct subset of patients.

2727

Clinical Manifestation (cont’d.)Clinical Manifestation (cont’d.) When CNS or heart involved, such cases: difficult When CNS or heart involved, such cases: difficult

to treat and outcome can be affected.to treat and outcome can be affected. Problem in interpreting literature on brucellosis is Problem in interpreting literature on brucellosis is

differentiating acute and chronic forms of differentiating acute and chronic forms of brucellosis. Because of necessity to treat patients brucellosis. Because of necessity to treat patients for prolonged periods, relapse not uncommon, for prolonged periods, relapse not uncommon, especially if therapy discontinued prematurely.especially if therapy discontinued prematurely.

Most relapses occur within 3 to 6 months of Most relapses occur within 3 to 6 months of discontinuing therapy.discontinuing therapy.

Disease considered chronic if infection persistsDisease considered chronic if infection persists

more than 12 months (arbitrary definition).more than 12 months (arbitrary definition).

2828

Clinical Manifestation (cont’d.)Clinical Manifestation (cont’d.) Chronic Brucellosis usually caused by persisting Chronic Brucellosis usually caused by persisting

deep foci of infection, e.g. suppurative lesions in deep foci of infection, e.g. suppurative lesions in bone, joints, liver, spleen or kidneys.bone, joints, liver, spleen or kidneys.

In contrast, some patients experience delyaed In contrast, some patients experience delyaed convalescence after treatment, with persisting convalescence after treatment, with persisting non-specific complaints of ill health, notably non-specific complaints of ill health, notably fatigue.fatigue.

Such disease distinguished from true chronic Such disease distinguished from true chronic brucellosis by absence of objective signs of brucellosis by absence of objective signs of disease, as fever, in addition, chronic brucellosis disease, as fever, in addition, chronic brucellosis characterized by persistently high IgG antibodies characterized by persistently high IgG antibodies titres in serum, but:-titres in serum, but:-

2929

Clinical Manifestation (cont’d.)Clinical Manifestation (cont’d.) Patients with delayed convalescence: poorly Patients with delayed convalescence: poorly

understood, some authorities attribute that to pre-understood, some authorities attribute that to pre-existing psychoneurosis exacerbated by existing psychoneurosis exacerbated by brucellosis.brucellosis.

Such patients present diagnostic dilemma, Such patients present diagnostic dilemma, because their complaints resemble brucellosis, but because their complaints resemble brucellosis, but further antimicrobial therapy, ineffective, and further antimicrobial therapy, ineffective, and patients often believe they suffer from incurable patients often believe they suffer from incurable brucellosisbrucellosis..

3030

Clinical Manifestation (cont’d.)Clinical Manifestation (cont’d.) Patients with delayed convalescence: poorly Patients with delayed convalescence: poorly

understood, some authorities attribute that to pre-understood, some authorities attribute that to pre-existing psychoneurosis exacerbated by existing psychoneurosis exacerbated by brucellosis.brucellosis.

Such patients present diagnostic dilemma, Such patients present diagnostic dilemma, because their complaints resemble brucellosis, but because their complaints resemble brucellosis, but further antimicrobial therapy, ineffective, and further antimicrobial therapy, ineffective, and patients often believe they suffer from incurable patients often believe they suffer from incurable brucellosis.brucellosis.

Relapse not usually caused by antibiotic Relapse not usually caused by antibiotic resistance, because strains of brucellae isolated resistance, because strains of brucellae isolated during relapse have antibiogram identical to during relapse have antibiogram identical to original infecting strains.original infecting strains.

3131

ComplicationsComplications

Nervous SystemNervous System

Direct CNS invasion by brucellosis less than 5%Direct CNS invasion by brucellosis less than 5% although depression and mental inattention occuralthough depression and mental inattention occur commonly in brucellosis.commonly in brucellosis. CNS Complications:-CNS Complications:- - Meningitis- Meningitis - Encephalitis- Encephalitis - Myelitis – radiculoneuritis- Myelitis – radiculoneuritis

3232

Complications (cont’d.)Complications (cont’d.)- Brain abscess- Brain abscess

- Epidural abscess- Epidural abscess - Demyelinating syndromes- Demyelinating syndromes - Meningovascular syndromes- Meningovascular syndromes - Acute and chronic meningitis: Most frequent- Acute and chronic meningitis: Most frequent CNS complication, and can be presentingCNS complication, and can be presenting finding, or occur late in disease course.finding, or occur late in disease course.

- Brucella meningitis difficult to distinguish from- Brucella meningitis difficult to distinguish from other causes of meningitis.other causes of meningitis.

3333

Complications (cont’d.)Complications (cont’d.) Nuchal rigidity occurs in <50% of cases.Nuchal rigidity occurs in <50% of cases. Brucella meningitis difficult to distinguish from Brucella meningitis difficult to distinguish from

other causesother causes CSF: Lymphocytic pleocytosis, elevated protein, CSF: Lymphocytic pleocytosis, elevated protein,

low to normal glucose.low to normal glucose. G. stain usually negative.G. stain usually negative. Culture positive <25% of cases.Culture positive <25% of cases. Diagnosis made by finding specific antibodies in Diagnosis made by finding specific antibodies in

CSFCSF

3434

Histologic findingsHistologic findings::

- Inflammation of leptomeninges- Inflammation of leptomeninges

- Adhesive arachnoiditis- Adhesive arachnoiditis

- Vasculitis- Vasculitis

- Leukoencephalitis- Leukoencephalitis

GIT 70% of patients with brucellosisGIT 70% of patients with brucellosis

- Anorexia, abd. Pain, nausea, vomiting, diarrhea

or constipation.

3535

GIT 70% of patients with brucellosis (cont’d)

- Pathologic lesions:- Pathologic lesions:

- Intestinal mucosa hyperemia with peyer’s- Intestinal mucosa hyperemia with peyer’s

patches inflammation.patches inflammation.

- Acute ileitis radiologically and histologically- Acute ileitis radiologically and histologically

in patients with colitis B. melitensis.in patients with colitis B. melitensis.

Hepatobiliary system (HPS)Hepatobiliary system (HPS)

- Liver, largest reticuloendothelial organ, probably- Liver, largest reticuloendothelial organ, probably

always involved in brucellosis.always involved in brucellosis.

- LFT, usually slightly elevated.- LFT, usually slightly elevated.

3636

Hepatobiliary system (HPS)Hepatobiliary system (HPS) - Brucella hepatitis pathologic findings- Brucella hepatitis pathologic findings spectrum is variable.spectrum is variable. - B. abortus infection: Granulomas- B. abortus infection: Granulomas indistinguishable from sarcoidosis.indistinguishable from sarcoidosis. - In contrast: B. melitensis: Lesions - In contrast: B. melitensis: Lesions range from small, almost insignificantrange from small, almost insignificant mononuclear cell aggregates surroundingmononuclear cell aggregates surrounding foci of necrosis scattered throughout foci of necrosis scattered throughout parenchyma, to diffuse non-specificparenchyma, to diffuse non-specific inflammation resembling viral hepatitis.inflammation resembling viral hepatitis.

3737

Hepatobiliary system (HPS) (cont’d.)Hepatobiliary system (HPS) (cont’d.)- Occasionally: Collections of mononuclear- Occasionally: Collections of mononuclear

cells forming loose granuloma may be cells forming loose granuloma may be found.found.

- Suppurative abscess of liver and spleen- Suppurative abscess of liver and spleen common with B. suis infection, andcommon with B. suis infection, and occasionally with B. melitensis.occasionally with B. melitensis.

- Hepatic lesions resolve with antimicrobial- Hepatic lesions resolve with antimicrobial therapy, and in absence of other causestherapy, and in absence of other causes (HCVm HBV, alcohol abuse). No cirrhosis,(HCVm HBV, alcohol abuse). No cirrhosis,

despite inflammation severity. despite inflammation severity.

3838

Hepatobiliary system (HPS) (cont’d.)Hepatobiliary system (HPS) (cont’d.)- Brucella rarely causes acute cholecystitis,- Brucella rarely causes acute cholecystitis,

pancreatitis and spontaneous bacterial pancreatitis and spontaneous bacterial peritonitis (SBP). peritonitis (SBP).

MSSMSS- Osteoarticular complications reported in 20-60%

of pts. infected with brucellosis. - Bone and joint lesions include:- ▪ Arthritis

▪ Spondylitis

3939

MSSMSS- Osteoarticular complications reported in 20-60%- Osteoarticular complications reported in 20-60%

of pts. infected with brucellosis.of pts. infected with brucellosis.- Bone and joint lesions include:- Bone and joint lesions include:

▪ ▪ ArthritisArthritis▪ ▪ SpondylitisSpondylitis▪ ▪ OsteomyelitisOsteomyelitis▪ ▪ TenosynovitisTenosynovitis▪ ▪ BursitisBursitis▪ ▪ Sacroiliitis most commonly reportedSacroiliitis most commonly reported

complication.complication.

4040

MSS (cont’d.)MSS (cont’d.)- Synovial fluid analysis from brucella effusions reveal:- Synovial fluid analysis from brucella effusions reveal: ▪ ▪ Mononuclear cells predominance, and brucellaeMononuclear cells predominance, and brucellae recovered in about 50% of casesrecovered in about 50% of cases.

▪ ▪ Reactive post infectious spondyloarthropathyReactive post infectious spondyloarthropathy described in some pts. This may be caused bydescribed in some pts. This may be caused by circulating immune complexes, but no associationcirculating immune complexes, but no association found with specific HLA phenotype.found with specific HLA phenotype.

▪ ▪ Spondylitis, predominantly, involving lumbar spineSpondylitis, predominantly, involving lumbar spine more common among elderly pts. and rarelymore common among elderly pts. and rarely associated with paraspinal abscess.associated with paraspinal abscess.

4141

MSS (cont’d.)MSS (cont’d.)▪ ▪ Radiographic abnormality generally occur late,Radiographic abnormality generally occur late,

but bone scans may detect inflammation earlybut bone scans may detect inflammation early in disease.in disease.

▪ ▪ Bone scan useful in differentiating sacroiliitisBone scan useful in differentiating sacroiliitis from hip joint involvement.from hip joint involvement.

▪ ▪ Earliest radiographic findings in spondylitis:Earliest radiographic findings in spondylitis: straightening of spine and narrowing of diskstraightening of spine and narrowing of disk

space. space. ▪ ▪ CT scan useful for detecting:CT scan useful for detecting:

- Joint destruction- Joint destruction - Vertebral osteomyelitis- Vertebral osteomyelitis - Paraspinal abscess- Paraspinal abscess

4242

C.V.S.

- Endocarditis occurs in less than 2% of cases,Endocarditis occurs in less than 2% of cases, but accounts for majority of brucellosis-relatedbut accounts for majority of brucellosis-related deaths.deaths.

- Before effective therapy, including valve replace-- Before effective therapy, including valve replace- ment surgery, Brucella endocarditis is nearlyment surgery, Brucella endocarditis is nearly always fatal.always fatal. - Aortic valve is affected more often than mitral- Aortic valve is affected more often than mitral valve.valve.

- Both native and prosthetic valve infections- Both native and prosthetic valve infections reported.reported.

4343

C.V.S. (cont’d.)C.V.S. (cont’d.)

- Mycotic aneurysms of brain, aorta and other vessels are secondary complications, especially in B. suis infections.

4444

Respiratory SystemRespiratory System

- Airborne transmission of brucellosis common- Airborne transmission of brucellosis common

in abbatoirs.in abbatoirs.

- Respiratory tract involvement ranges from flu-- Respiratory tract involvement ranges from flu-

like illness with normal chest radiograph resultslike illness with normal chest radiograph results

to bronchitis, broncopneumonia, lung nodules,to bronchitis, broncopneumonia, lung nodules,

miliary lesions, hilar adenopathy and pleuralmiliary lesions, hilar adenopathy and pleural

effusions.effusions.

- Rarely brucellae identified by stain or culture- Rarely brucellae identified by stain or culture

of expectorated sputumof expectorated sputum.

4545

G. U. T.G. U. T.- Renal involvement is rare, although brucella- Renal involvement is rare, although brucella

have been recovered from urine.have been recovered from urine. - Interstitial nephritis, pyelonephritis, exudative- Interstitial nephritis, pyelonephritis, exudative glomerulonephritis, and IgA nephropathy haveglomerulonephritis, and IgA nephropathy have been reported.been reported.

- Orchitis occurs in up 20% of men with- Orchitis occurs in up 20% of men with brucellosis. brucellosis.

- Testes or epididymis infiltrated with lympho-- Testes or epididymis infiltrated with lympho- cytes and plasma cells and there is atrophy ofcytes and plasma cells and there is atrophy of seminiferous tubules.seminiferous tubules.

4646

G.U.T. cont’d.)G.U.T. cont’d.)- In women, rare cases salpingitis, cervicitis and- In women, rare cases salpingitis, cervicitis and

pelvic abscess reported.pelvic abscess reported.

- Principal brucellosis in animals is spontaneous- Principal brucellosis in animals is spontaneous

abortion and presence of erythritol in tissues ofabortion and presence of erythritol in tissues of

susceptible animals, thought to play role insusceptible animals, thought to play role in

localization of brucellae in genital tract.localization of brucellae in genital tract.

- Brucellosis can result in human abortions, but- Brucellosis can result in human abortions, but

unclear whether it is more frequent than withunclear whether it is more frequent than with

other bacteremic infections. other bacteremic infections.

4747

Hematologic ComplicationsHematologic Complications- Hematologic manifestations of brucellosis

include: anemia, leukopenia, thrombo- cytopenia and clotting disorders.

- Granulomas found in B. marrow in up to 75% of cases, but they are small and indistinct. - Severe thrombocytopenia with cutaneous purpura reported and maybe associated with antiplatelets antibodies, or hemophagocytic histiocytes in bone marrow.

4848

Cutaneous Complications

- Cutaneous lesions occur in 5% of patients with

brucellosis.

- Many transient, nonspecific lesions described,

including rashes, papules, ulcers, petechiae,

purpura, and vasculitis.

4949

Ocular ComplicationsOcular Complications- Many ocular complications reported in patients- Many ocular complications reported in patients

with brucellosis.with brucellosis.

- Uveitis, late manifestation, consisting of chronic- Uveitis, late manifestation, consisting of chronic

iridocyclitis, mummular keratitis, multifocaliridocyclitis, mummular keratitis, multifocal

choroiditis, and optic neuritis.choroiditis, and optic neuritis.

- Brucella uveitis considered non-infectious- Brucella uveitis considered non-infectious

immune response that response to topicalimmune response that response to topical

and systemic corticosteroid therapy.and systemic corticosteroid therapy.

- Rare cases of endophthalmitis reported, in - Rare cases of endophthalmitis reported, in

which brucellae isolated from vitreous humor.which brucellae isolated from vitreous humor.

5050

DiagnosisDiagnosis

- - Because sx. of brucellosis nonspecific, it isBecause sx. of brucellosis nonspecific, it is

important to:important to:

▪ ▪ Obtain detailed history including:Obtain detailed history including:

- Occupation, exposure to animals, travel to- Occupation, exposure to animals, travel to

enzootic areas, and ingestion of high-riskenzootic areas, and ingestion of high-risk

foods, as unpasteurized dairy products.foods, as unpasteurized dairy products.

- WBC: normal or low, and may not suggest- WBC: normal or low, and may not suggest

infectious process.infectious process.

- Anemia, leukopenia, and thrombocytopenia,- Anemia, leukopenia, and thrombocytopenia,

common findings.common findings.

5151

Diagnosis (cont’d.)Diagnosis (cont’d.)- - E.S.R. variable and of little diagnostic value.E.S.R. variable and of little diagnostic value.

- Diagnosis of brucellosis made with certainty,- Diagnosis of brucellosis made with certainty,

when brucellae recovered from blood, bonewhen brucellae recovered from blood, bone

marrow, or other tissues.marrow, or other tissues.

- Rate of isolation from blood ranges from 15-- Rate of isolation from blood ranges from 15-

70% depending on methods used and70% depending on methods used and

incubation period.incubation period.

- When brucellosis is suspected, - When brucellosis is suspected, Lab. should beLab. should be

informed to maintain cultures for minimum of informed to maintain cultures for minimum of

4 weeks.4 weeks.

5252

Diagnosis (cont;d.)Diagnosis (cont;d.)

- Bone marrow cultures have higher yield than- Bone marrow cultures have higher yield than

blood.blood.

- Most Labs. Now use rapid isolation techniques,- Most Labs. Now use rapid isolation techniques,

(e.g. BACTEC, Dupont Isolator…etc.), which (e.g. BACTEC, Dupont Isolator…etc.), which

are satisfactory for recovering brucellae.are satisfactory for recovering brucellae.

- Faster isolation time reported for lysis- Faster isolation time reported for lysis

concentration method.concentration method.

- Preliminary studies using PCR, with random or- Preliminary studies using PCR, with random or

selected primers, are promising, but requireselected primers, are promising, but require

additional evaluation.additional evaluation.

5353

Diagnosis (cont’d.)Diagnosis (cont’d.) - Presumptive identification of brucella spp. Made- Presumptive identification of brucella spp. Made

on the basis of morphologic, cultural, and sero-on the basis of morphologic, cultural, and sero- logic features, but confirmation requires:logic features, but confirmation requires:

- Oxidative metabolism- Oxidative metabolism- Phage-typing, or genotyping procedures.- Phage-typing, or genotyping procedures.

- Results of rapid bacterial identification system- Results of rapid bacterial identification system

should be interpreted with caution, becauseshould be interpreted with caution, because some brucella isolates misidentified assome brucella isolates misidentified as moraxella phenylpyruvica.moraxella phenylpyruvica.

5454

Diagnosis (cont’d.)Diagnosis (cont’d.)- In the absence of bacteriologic confirmation, - In the absence of bacteriologic confirmation,

presumptive diagnosis made on the basis of high presumptive diagnosis made on the basis of high or rising titers of specific antibodies.or rising titers of specific antibodies.

- Variety of serologic tests applied to brucellosis, - Variety of serologic tests applied to brucellosis, SAT, most widely used.SAT, most widely used.

- No single titer of brucella antibodies always - No single titer of brucella antibodies always “diagnostic”, but, most cases of active infection, “diagnostic”, but, most cases of active infection, have titer have titer higher than 1:160higher than 1:160..

- Rose Bengal test, rapid screening method, but - Rose Bengal test, rapid screening method, but positive sera positive sera should always be confirmed by SAT.should always be confirmed by SAT.

5555

Diagnosis (cont’d.)Diagnosis (cont’d.)

- “Febrile agglutinin” tests insensitive, and should- “Febrile agglutinin” tests insensitive, and should not be relied on for diagnosis.not be relied on for diagnosis.

- False-negative reactions in SAT, result from- False-negative reactions in SAT, result from prozone phenomenon, and false-positive resultsprozone phenomenon, and false-positive results from cross-reaction with antibodies to yersinia,from cross-reaction with antibodies to yersinia, cholera, and tularemia.cholera, and tularemia.

- False-negative and false-positive reactions,- False-negative and false-positive reactions, avoidable by routinely diluting serum beyondavoidable by routinely diluting serum beyond 1:320.1:320.

5656

Diagnosis (cont’d.)Diagnosis (cont’d.)

- V. rarely, presence of blocking antibodies causes- V. rarely, presence of blocking antibodies causes

negative reaction, but, blocking substancesnegative reaction, but, blocking substances

identifiable by coombs test or blocking assayidentifiable by coombs test or blocking assay..

- Brucella “ELISA” can be definitive, when aggluti-- Brucella “ELISA” can be definitive, when aggluti-

nation tests equivocal. nation tests equivocal.

5757

TreatmentTreatment- Antimicrobial therapy of brucellosis relieves- Antimicrobial therapy of brucellosis relieves

symptoms, shortens illness duration, andsymptoms, shortens illness duration, and reduces complication incidence, some of thesereduces complication incidence, some of these complications be life-threatening.complications be life-threatening. - Variety of agents active against brucellae, but- Variety of agents active against brucellae, but in vitro susceptibility results do not alwaysin vitro susceptibility results do not always predict clinical efficacy, e.g. Beta-Lactam anti-predict clinical efficacy, e.g. Beta-Lactam anti- biotics active in vitro, yet often clinicallybiotics active in vitro, yet often clinically ineffective.ineffective.

5858

Treatment (cont’d.)Treatment (cont’d.)- Intracellular localization of brucellae, believed to - Intracellular localization of brucellae, believed to

offer some protection against antimicrobials, thusoffer some protection against antimicrobials, thus drugs with good intra-cellular penetration are drugs with good intra-cellular penetration are necessary for cure.necessary for cure.

- Tetracyclines among most active drugs for- Tetracyclines among most active drugs for treating brucellosis, but, relapse rate unaccept-treating brucellosis, but, relapse rate unaccept- ably high with single-drug therapy, thus combi-ably high with single-drug therapy, thus combi- nation therapy is recommended.nation therapy is recommended.

- Many studies showed tetracycline (500 mg PO x- Many studies showed tetracycline (500 mg PO x 4 times daily combined with streptomycin4 times daily combined with streptomycin (1 g/day I.M.) for three weeks is the most(1 g/day I.M.) for three weeks is the most effective treatment.effective treatment.

5959

Treatment (cont’d.)Treatment (cont’d.)- Doxycycline, given (200 mg PO/day), has fever- Doxycycline, given (200 mg PO/day), has fever

GIT side effects, thus becomes tetracyline ofGIT side effects, thus becomes tetracyline of

choice.choice.

- WHO, 1986, recommended use of - WHO, 1986, recommended use of DoxycyclineDoxycycline

200 mg, once daily orally, combined with200 mg, once daily orally, combined with

RifampicinRifampicin (600-900 mg once daily orally), both (600-900 mg once daily orally), both

given for 6 weeks, as combination of choice.given for 6 weeks, as combination of choice.

-- Subsequent studies concluded that:Subsequent studies concluded that:

- Doxycycline + Streptomycin - Doxycycline + Streptomycin is more effectiveis more effective

than than

6060

Treatment (cont’d.)Treatment (cont’d.)- Doxycycline + Rifampicin, especially for pts. with- Doxycycline + Rifampicin, especially for pts. with

complications such as spondylitis.complications such as spondylitis.

- Rifamcpicin reported effective for treating- Rifamcpicin reported effective for treating

brucellosis during pregnancy.brucellosis during pregnancy. - Inclusion of aminoglycosides in treatment- Inclusion of aminoglycosides in treatment

regimen suggested, by studies, to be synergisticregimen suggested, by studies, to be synergistic

with other agents in vitro and clinical use.with other agents in vitro and clinical use.

6161

Treatment (cont’d.)Treatment (cont’d.) - Streptomycin used as preferred aminoglycoside- Streptomycin used as preferred aminoglycoside by most studies, reasons exist to use Gentaminby most studies, reasons exist to use Gentamin instead, because Gentamicin is more active ininstead, because Gentamicin is more active in vitro, less toxic, and can be given as single dailyvitro, less toxic, and can be given as single daily dose (SDD). However, more studies needed todose (SDD). However, more studies needed to establish optimal schedule and compare bothestablish optimal schedule and compare both agents (Strept. & Genta.)agents (Strept. & Genta.)

- Cotrimoxazole (TMP + SMX), gained initial- Cotrimoxazole (TMP + SMX), gained initial enthusiasm, but subsequent comparativeenthusiasm, but subsequent comparative

studies revealed unacceptable relapse rate.studies revealed unacceptable relapse rate.

6262

Treatment (cont’d.)Treatment (cont’d.)- Cotrimoxazole + Aminoglycoside reported to be- Cotrimoxazole + Aminoglycoside reported to be successful in treating children younger than 8successful in treating children younger than 8

years of age, an age in which teeth stainingyears of age, an age in which teeth staining contraindicates Tetracycline use.contraindicates Tetracycline use.

- Quinolones use found disappointing, despite in- Quinolones use found disappointing, despite in vitro activity and good cellular penetration. vitro activity and good cellular penetration.

Thus,Thus, these agents are best reserved as adjunctivethese agents are best reserved as adjunctive therapy.therapy.

- Special problems arise in treating brucella- Special problems arise in treating brucella complications, as meningitis, endocarditis, andcomplications, as meningitis, endocarditis, and no consensus of opinions regarding optimalno consensus of opinions regarding optimal regimen.regimen.

6363

Treatment (cont’d.)Treatment (cont’d.)

- Most authorities recommend: Doxycycline in- Most authorities recommend: Doxycycline in

combination with two or more other drugs withcombination with two or more other drugs with

treatment continued for many months dependingtreatment continued for many months depending

on response.on response.

- Doxycycline crosses BBB, better than generic - Doxycycline crosses BBB, better than generic

Tetracycline, and use successfully withTetracycline, and use successfully with

Cotrimoxazole (TMP/SMX) and Rifampicin forCotrimoxazole (TMP/SMX) and Rifampicin for

brucella meningitis and endocarditis.brucella meningitis and endocarditis.

6464

Treatment (cont’d.)Treatment (cont’d.)

- Third generation cephalosporins achieve high - Third generation cephalosporins achieve high

concentration in CSF, but brucella spp.concentration in CSF, but brucella spp.

susceptibility variable, thus in vitro sensitivitysusceptibility variable, thus in vitro sensitivity

should be ensured.should be ensured.

- Despite cure of brucella endocarditis, cases- Despite cure of brucella endocarditis, cases

with antibiotic alone, most cases requirewith antibiotic alone, most cases require

combined medical-surgical approach.combined medical-surgical approach.

- Corticosteroids often recommended from- Corticosteroids often recommended from

neurobrucellosis, but, in the absence ofneurobrucellosis, but, in the absence of

controlled studies, their efficacy is unproved.controlled studies, their efficacy is unproved.

6565

** In K.S.A., because Rifampicin is one of theIn K.S.A., because Rifampicin is one of the

essential first line drugs for treating tuberculosis,essential first line drugs for treating tuberculosis,

its use in brucellosis, should be reserved for its use in brucellosis, should be reserved for specific indications (e.g. neurobrucellosis, specific indications (e.g. neurobrucellosis, Brucella endocarditis and Brucellosis during Brucella endocarditis and Brucellosis during pregnancypregnancy..

6666

PreventionPrevention

- Prevention of human brucellosis depend on:- Prevention of human brucellosis depend on:

Control and elimination of Brucellosis in domesticControl and elimination of Brucellosis in domestic

animals.animals.

- Effective attenuated live bacterial vaccines exist- Effective attenuated live bacterial vaccines exist

for:for:

- B. abortus (Strain 19)- B. abortus (Strain 19)

- B. melitensis (Strain Rev-1)- B. melitensis (Strain Rev-1)

- No vaccines for B. suis and B. canis- No vaccines for B. suis and B. canis

- On rare occasions, accidents with 19 and Rev-1- On rare occasions, accidents with 19 and Rev-1

caused human brucellosis.caused human brucellosis.

6767

Prevention (cont’d.)Prevention (cont’d.)- B. abortus strain RB51 (stable rough mutant)- B. abortus strain RB51 (stable rough mutant)

largely replaced strain 19 as preferred bovinelargely replaced strain 19 as preferred bovine

vaccine (USA).vaccine (USA).

- Strain RB51, has advantage of protecting cattle- Strain RB51, has advantage of protecting cattle

without inducing antibody response, and RB51without inducing antibody response, and RB51

appears to lack virulence for humans andappears to lack virulence for humans and

despite accidents, no proven cases of humandespite accidents, no proven cases of human

RB51 infection.RB51 infection.

- No licensed human vaccine again on brucellosis- No licensed human vaccine again on brucellosis

to deal.to deal.