William E. Maher

Revised interpretation of oxacillin MICs for Staphylococcus epidermidis based on mecA detection.

In 1992 and 1993, at The Ohio State University Medical Center, a larger proportion of Staphylococcus epidermidis strains required oxacillin MICs of 1 to 2 micrograms/ml than did Staphylococcus aureus strains. mecA genotype was correlated with antimicrobial susceptibility for selected clinical S. epidermidis strains. All 14 strains that required oxacillin MICs of < or = 0.25 microgram/ml and 2 of 5 strains that required oxacillin MICs of 0.5 microgram/ml were susceptible by 1-microgram oxacillin disk test and were mecA negative. Three of 5 strains that required oxacillin MICs of 0.5 microgram/ml and all 18 strains that required oxacillin MICs of > or = 1.0 microgram/ml were resistant by oxacillin disk test and were mecA positive. Current National Committee for Clinical Laboratory Standards MIC interpretive criteria may underestimate methicillin resistance among S. epidermidis strains.

Cerebellar Atrophy Associated With Human Immunodeficiency Virus Infection

A 30-YEAR-OLD WOMAN known to have human immunodeficiency virus infection for 10 years presented with a 3-month history of stumbling, poor coordination, falls, and dysarthria. She had been starting and stopping use of several human immunodeficiency virus medications since her diagnosis, including a combination of lopinavir and ritonavir and a combination of zidovudine, lamivudine, and abacavir sulfate, but had not taken any medications for 3 years before presentation. She had no family history of similar illness. The results of physical examination were notable for severe dysarthria, nystagmus, finger-nosefinger and heel-knee-shin dysmetria, intention tremor, and impaired rapid alternating movements. She had severe truncal ataxia and was unable to stand. She had no cognitive, sensory, or motor deficits. Head computed tomography (Figure 1) and magnetic resonance imaging (Figure 2) revealed severe cerebellar atrophy. Fluid-attenuated inversion recovery magnetic resonance images, T2 sequences, and postcontrast images revealed no abnormalities except for cerebellar atrophy. Cerebrospinal fluid analysis revealed no pleocytosis, with a protein level of 0.053 g/dL (to convert to grams per liter, multiply by 10.0), and the patient had a negative VDRL test result. Her CD4 cell count was 186/μL, and her human immunodeficiency virus RNA viral load was 210 000 copies/mL. The results of her toxicology screening, autoimmune screening, and paraneoplastic antibody panel were negative; vitamin B12, vitamin E, and thyrotropin levels were normal.

Disseminated Gonococcal Infection and Eculizumab—a “high Risk” Connection?

A 28-year-old woman who was undergoing treatment with eculizumab for paroxysmal nocturnal hemoglobinuria presented to the hospital with fevers, chills, headache, and a swollen left index finger. Blood cultures returned positive for Neisseria gonorrhoeae. We report the second case of disseminated gonococcal infection associated with the use of eculizumab.

A rare case of Neisseria bacilliformis native valve endocarditis

Neisseria bacilliformis has most often been associated with infections of the oral cavity and the respiratory tract. We report a case of N. bacilliformis mitral valve endocarditis in a previously healthy adult which required valve replacement, thus confirming the opportunistic nature and pathogenic potential of this novel organism.

Naturally-occurring, osmo-remedial variants of Escherichia coli

Two clones of Escherichia coli O27:K1:H31 and O2:H7, isolated from patients with urinary tract infection or bacteraemia, failed to grow in a synthetic minimal medium (MM) of low osmolality. They were considered to be osmo-remedial because they grew well when sufficient amounts of NaCl, mannitol or sucrose were added to raise the osmolality of the medium to > 300 mOsm/kg. The defect could also be corrected by nicotinamide or its precursors quinolinic and aspartic acids. Each clone had a unique DNA restriction enzyme profile, fimbriae and antibiotic susceptibility patterns. The osmo-remedial variants were unstable and underwent phenotypic modulation to form mixtures with osmo-tolerant forms when grown in MM. They tended to form satellites of small colonies around large colonies of osmo-tolerant cells on MM agar plates. The penicillin method of Davis was used to separate the two forms. Nicotinamide induced the expression of ompF when the osmo-remedial strains were grown under conditions of low osmolality. It is possible that the variants are defective in the synthesis of membrane-derived oligosaccharides or outer-membrane proteins, but this has yet to be determined.