Steven L. Berk

Meningitis Caused by Gram-Negative Bacilli

Thirty adults with meningitis caused by gram-negative bacilli were observed from 1968 to 1978 at four hospitals associated with Boston University School of Medicine. Equal numbers of two distinct types of gram-negative bacillary meningitis--spontaneously occurring meningitis and meningitis after neurosurgery--were found. Spontaneously occurring meningitis appeared to be caused most often by Escherichia coli and Haemophilus influenzae. Meningitis occurring after neurosurgical procedures was more insidious in onset, more protracted in course, and more often caused by organisms resistant to multilple antibiotics. Approaches to therapy are based on the differences in character of these two types of meningitis.

Pulmonary tuberculosis in elderly men

The clinical manifestations, predisposing factors, and diagnostic approach to 29 young men and 35 elderly men with pulmonary tuberculosis admitted to a Veterans Administration hospital were compared. Elderly men had a higher number of underlying conditions such as atherosclerosis, previous gastrectomy, and malignancy, whereas alcoholism was more prevalent in the younger group. The classic symptoms and signs of tuberculosis were noted in a significantly higher proportion of the younger group: fever (62 percent versus 31 percent), weight loss (76 percent versus 34 percent), night sweats (48 percent versus 6 percent), sputum production (76 percent versus 48 percent), and hemoptysis (40 percent versus 17 percent) (p less than 0.05). Abnormal mentation was more common in the elderly group (31 percent versus 10 percent) (p less than 0.05). Radiographic findings were similar in both groups. Mortality related to tuberculosis was 20 percent in elderly men versus 3 percent in the younger men (p less than 0.05). Tuberculosis is frequently not considered in the differential diagnosis when elderly patients present with multiple medical problems and nonspecific complaints. Since there are differences in the clinical presentation and the outcome of pulmonary tuberculosis in elderly patients, a high index of suspicion for the disease should be maintained.

Interferon-alpha Upregulates Gene Expression of Aquaporin-5 in Human Parotid Glands

Aquaporins are a family of homologous membrane proteins that function as highly selective water channels. Aquaporin-5 (AQP5) is uniquely present in lacrimal and salivary glands, where it accounts for normal tear and saliva production. We tested the hypothesis that orally administered human interferon-alpha (HuIFN-alpha) benefits persons with xerostomia by augmenting the production of AQP5 protein by parotid gland epithelium. Cells from three human parotid glands were cultured with and without human lymphoblastoid IFN-alpha, and assayed for AQP5 mRNA levels by reverse transcriptase polymerase chain reaction (RT-PCR), and AQP5 protein levels by Western blot. Intracellular localization of AQP5 protein was done using confocal microscopy. The functional integrity of the glandular tissue was confirmed by RT-PCR analysis of alpha-amylase 1 and basic proline-rich protein transcripts. AQP5 was constitutively expressed in human parotid gland tissue, with AQP5 protein restricted to the plasma membranes and cytoplasmic vesicles of acinar cells. IFN-alpha augmented AQP5 transcription and protein production in a concentration-dependent manner, and increased the size of intensity of staining of AQP5-containing cytoplasmic vesicles in acinar cells. We conclude that IFN-alpha upregulates AQP5 gene expression in human parotid acinar cells in vitro. To our knowledge, this is the first demonstration that IFN-alpha regulates the gene expression of an aquaporin.

In vitro activity of fosfomycin, alone and in combination, against methicillin-resistant Staphylococcus aureus.

We tested 148 strains of clinical isolates of methicillin-resistant Staphylococcus aureus against fosfomycin alone and in combination with methicillin, cefamandole, gentamicin, trimethoprim, and vancomycin. Fosfomycin inhibited 90% of the 148 methicillin-resistant S. aureus strains at a concentration of 4 micrograms/ml. Synergism was observed in 97 strains (66%) with fosfomycin-cefamandole and in 69 strains (46%) with fosfomycin-methicillin. The combinations of fosfomycin with vancomycin, gentamicin, and trimethoprim were indifferent in most strains.

Pulmonary strongyloidiasis. Diagnosis by Sputum Gram stain

Sputum Gram stain was diagnostic for pulmonary strongyloidiasis in four patients from Tennessee with chronic obstructive lung disease treated with steroids. The case reports of these patients and photomicrographs of the larval forms by Gram stain are presented. Sputum Gram stain may be a useful procedure to screen for pulmonary strongyloidiasis in steroid-treated patients with chronic lung disease who come from an endemic area.

In vitro susceptibilities and beta-lactamase production of 53 clinical isolates of Branhamella catarrhalis.

We tested 53 clinical isolates of Branhamella catarrhalis recovered from patients with respiratory symptoms to determine the susceptibility of the isolates to 25 antimicrobial agents, including the newer beta-lactam antibiotics. Of the 53 strains, 46 (86.7%) were beta-lactamase producers. All the strains were susceptible to the majority of the new penicillins and cephalosporins. The combinations of amoxacillin-clavulanic acid and ticarcillin-clavulanic acid were also very active against the beta-lactamase-producing strains.

Enterococcal pneumonia: Occurrence in patients receiving broad-spectrum antibiotic regimens and enteral feeding

Enterococcal pneumonia occurred as a superinfection in two patients who received broad-spectrum antibiotic therapy. Both patients were receiving enteral hyperalimentation by Dobb-Hoff tube. The organism was isolated from transtracheal aspirate in pure culture and gram-positive cocci were visible on gram-stained smear. Enterococcal pneumonia may occur in patients receiving cephalosporin-aminoglycoside therapy, and may be anticipated as a consequence of third-generation cephalosporin therapy.

Pneumonia caused by gram-negative bacilli

Gram-negative bacillary pneumonia has become an increasingly important disease in immunosuppressed, elderly, and hospitalized patients. The clinical features, etiologic agents, population at risk, treatment, and outcome in patients with well-documented gram-negative pneumonia were compared in two groups of patients: those with bacteremic pneumonia and those with nonbacteremic pneumonia documented by transtracheal aspiration. Clinical features were frequently subtle in both groups. A wide range of gram-negative bacilli were implicated as pathogens and pneumonias documented by transtracheal aspiration were frequently mixed infections. Pseudomonas aeruginosa and Serratia marcescens were the most common pathogens causing bacteremic pneumonias, whereas Escherichia coli and Klebsiella were more common in the nonbacteremic group. Gram-negative bacillary pneumonia was frequently a lethal disease despite two-drug therapy, particularly in bacteremic patients.

Necrotizing fasciitis and nonsteroidal anti-inflammatory drugs.

We have presented a case of fulminant necrotizing fasciitis that occurred after excessive NSAID intake with granulocytopenia. This case parallels those previously reported as outlined in the above discussion. We concur with previous investigators who have concluded that NSAIDs should be used with caution in patients with phlebitis or apparently benign inflammatory cutaneous lesions.

Emerging pathogens in nosocomial pneumonia

The organisms responsible for nosocomial pneumonia are continuously evolving. Gramnegative bacilli have become the most common etiologic agents over the past 20 years, and with this evolution has come a better understanding of the pathogenesis of gram-negative bacillary pneumonia. Some gram-positive cocci, such as enterococci, group B beta hemolytic streptococci and methicillin-resistantStaphylococcus aureus, haven taken on new significance in nosocomial respiratory infections.Streptococcus pneumoniae, nontypeableHaemophilus influenzae andBranhamella catarrhalis are increasingly reported in hospitalized patients with chronic lung disease. Etiologic agents will change as new antibiotics are introduced. A better understanding of etiologic agents and their pathogens may be the best tool toward preventing hospital-acquired pneumonia.