Tags: Cefotaxime

Borrelia & Leptospira Species

BORRELIA SPECIES RELAPSING FEVER Essentials of Diagnosis The most common presentation is fever with rash, headache, shaking chills, myalgias, arthralgias, and — during the acute phase — hepatosplenomegaly. Louse-borne relapsing fever (LBRF) is epidemic, caused by B. recurrentis, and characterized by one or two relapses. Tick-borne relapsing fever (TBRF) is endemic, caused by several Borrelia species, and characterized by multiple clinical relapses. Organisms can be visualized in blood smears of febrile patients, unlike other spirochetal pathogens, using dark-field microscopy or Giemsa or Wright stains. Helical (3-10 spirals) spirochetes, 8-30 um × 0.3 um, motile (flagella). Weil-Felix reaction: Proteus OX-K agglutinin titers are elevated (this is more common in LBRF). General Considerations […]

Brucella, Francisella, Pasteurella, Yersinia, & Hacek

BRUCELLOSIS Essentials of Diagnosis Suspected in patients with chronic fever of unknown etiology who have a history of occupational exposure or come from a high prevalence area. Leukopenia. Blood culture or bone marrow cultures on appropriate media. Serum antibody titer = 1:160. Polymerase chain reaction. General Considerations Brucellosis (also called undulant fever, Mediterranean fever, Malta fever) is an infection that causes abortion in domestic animals. It is caused by one of six species of Brucella coccobacilli. It may occasionally be transmitted to humans, in whom the disease could be acute or chronic with ongoing fever and constitutional symptoms without localized findings. Epidemiology Brucellosis is transmitted to humans by either direct contact […]

Vibrio & Campylobacter

VIBRIO CHOLERAE INFECTIONS Essentials of Diagnosis History of exposure, particularly travel to endemic or epidemic locales. Acute onset of voluminous, watery diarrhea, with low-grade fever and mild abdominal pain, which are disproportionate to the amount of diarrhea. During outbreaks, the presence of straight-to-curved gram-negative bacilli, with a single polar flagellum, in the stool of infected patients. In wet preparations, these organisms demonstrate a characteristic darting or "shooting star" motility. The identification may be confirmed by motility inhibition with specific antisera. Cultures of V cholerae from stool with differential media, such as thiosulfate-citrate-bile salts-sucrose (TCBS) medium. Bacterial growth in nutrient broth, without 1% NaCl supplementation. This characteristic is useful for separating V […]

Extraintestinal Disease

Clinical Findings Signs and Symptoms Patients with septicemia, wound infections, or ear infections caused by a Vibrio species frequently have a history of shellfish ingestion or saltwater exposure. Clinical manifestations vary depending on the site of infection. Healing wounds, in appropriately exposed individuals, may become secondarily infected by marine vibrios. Suppuration may occur, and subcutaneous abscesses may form. A spreading, violaceous appearance around the wound, which is warm to the touch is indicative of cellulitis. The clinical findings of V alginolyticus-associated otitis media are nonspecific. Findings in V alginolyticus-associated otitis externa include a reddened, often painful external auditory canal. In immunocompromised and debilitated patients, especially those with liver cirrhosis, a septicemia […]

Haemophilus, Bordetella, & Branhamella Species

HAEMOPHILUS INFLUENZAE & OTHER HAEMOPHILUS SPECIES Essentials of Diagnosis Haemophilus influenzae is generally acquired via the aerosol route or by direct contact with respiratory secretions. The most common associated syndromes include otitis media, sinusitis, conjunctivitis, bronchitis, pneumonia, and, to a lesser extent, meningitis, epiglottitis, arthritis, and cellulitis. Gram stain shows pleomorphic gram-negative coccobacilli. In cases of meningitis, epiglottitis, arthritis, and cellulitis, organisms are typically recovered from blood, and type-b polysaccharide capsular material may be detected in the urine. Organisms and type-b polysaccharide capsule may also be present in other appropriate sterile body fluids, such as cerebrospinal fluid (CSF) in meningitis and joint fluid in arthritis. General Considerations Epidemiology Before 1990, strains […]

Haemophilus Influenzae: Clinical Syndromes

H influenzae was first isolated during the 1892 influenza pandemic and was originally believed to be the causative agent of influenza. Although subsequent studies revealed the fallacy of this idea, H influenzae has proved to be a common cause of localized respiratory tract and systemic disease, including meningitis, epiglottitis, pneumonia, pyogenic arthritis, cellulitis, otitis media, and sinusitis, among others (Box 1). MENINGITIS Meningitis is the most common and serious form of invasive H influenzae type-b disease. In the mid-1980s, before the introduction of effective vaccines, ~ 10,000-12,000 cases of H influenzae type-b meningitis occurred in the United States each year, and 95% of cases involved children < 5 years old. Nowadays, […]

Neisseria Meningitidis

Essentials of Diagnosis Transmission in crowded or closed populations. Meningitis most common, but bacteremia, pneumonia, and other syndromes can occur in absence of meningitis. Disease often associated with petecchial or purpuric rash, which may involve palms and soles. Neutrophil-predominant cell profile in CSF, with low-glucose and high-protein concentrations. Gram-negative diplococci inside neutrophils on stained smears of CSF and aspirated skin lesions. Fastidious organism requires special media and growth conditions. Blood and CSF most useful specimens for recovery of organism. Improved sensitivity of detection with PCR in CSF, but not widely available. General Considerations Epidemiology N meningitidis is found only in humans and is a member of the normal oropharyngeal flora in […]

Streptococcus Dysgalactiae Subspp. Equisilimis & Streptococcus Zooepidemicus: Clinical Syndromes

PHARYNGITIS The symptoms of pharyngitis caused by these organisms mimic those of S pyogenes pharyngitis (Box 50-1; see also site). Poststreptococcal glomerulonephritis has been described following S dysgalactiae subspp. equisimilis and S zooepidemicus pharyngitis. Notably, however, no antistreptolysin O antibody response will be detected as these organisms do not produce streptolysin O. S dysgalactiae subspp. equisimilis pharyngitis has been associated with sterile reactive arthritis. Acute rheumatic fever, however, has not been described in association with S dysgalactiae subspp. equisimilis and S zooepidemicus pharyngitis. SKIN & SOFT TISSUE INFECTIONS Cellulitis, wound infections, pyoderma, erysipelas, impetigo, and cutaneous ulcers can be caused by these organisms (see site). Breaches in skin integrity may provide […]

Other Gram-Positive Cocci

VIRIDANS GROUP STREPTOCOCCI, INCLUDING ABIOTROPHIA DEFECTIVA & ABIOTROPHIA ADJACENS Essentials of Diagnosis Facultatively anaerobic gram-positive cocci, catalase negative, coagulase negative. a or ß hemolytic on blood agar. Abiotrophia defectiva and Abiotrophia adjacens require pyridoxal or thiol group supplementation. Streptococcus milleri group organisms often exhibit Lancefield antigens A, C, F, or G and often have a butterscotch odor. General Considerations Epidemiology Viridans streptococci are part of the normal microbial flora of humans and animals and are indigenous to the upper respiratory tract, the female genital tract, all regions of the gastrointestinal tract, and, most significantly, the oral cavity. Clinically significant species that are currently recognized as belonging to the viridans group of […]

Streptococcus Pneumoniae

Essentials of Diagnosis Most common infections include pneumonia, meningitis, sinusitis, and otitis media. Predisposing factors include extremes of age (ie, infants and elderly) and underlying host defects in antibody, complement, and splenic function. Transmission is human to human both in the community and nosocomially. Pneumonia: productive cough, fever, chills, sweats, and dyspnea; lobar or segmental consolidation on chest x-ray; lancet-shaped gram-positive diplococci on Gram stain of sputum or growth of S pneumoniae from sputum, blood, or pleural fluid. Meningitis: headache, stiff neck, fever, chill, and photophobia; nuchal rigidity, Kernig's or Brudzinski's sign; lancet-shaped gram-positive diplococci on Gram stain of cerebrospinal fluid (CSF), growth of S pneumoniae from CSF or blood, or […]