Infection control and outpatient parenteral antibiotic therapy.

Outpatient procedures have become more complex, requiring outpatient providers to offer technical procedures in the home, office, and clinic. This shift in health care has brought about the need for staff members to become proficient in a variety of technical procedures that were once done only in the hospital setting. Outpatient i.v. therapy has caused home health care agencies, physicians' offices, and clinics to seek education and training regarding i.v. therapy and to develop basic infection-control guidelines and guidelines related to the insertion and maintenance of i.v. devices. The goals of the outpatient provider are to prevent i.v.-related complications and to provide quality patient care. These can be accomplished by strict adherence to sound infection-control guidelines and routine monitoring of procedure techniques and complications of care. Outpatient providers may wish to seek expertise and guidance from hospital infection-control personnel, infectious diseases specialists, or other infection-control consultants to meet the demands of the complexity of outpatient care.

Invasive infection due to Apophysomyces elegans in immunocompetent hosts.

A previously well 59-year-old man developed necrotizing, invasive cellulitis and subsequent osteomyelitis at what was judged to be the site of a bite or sting. The pathogen isolated was Apophysomyces elegans. Eventually, in addition to treatment with intravenous amphotericin B, en bloc resection was required for cure. Only six previous cases of A. elegans infection have been reported in the literature. The lack of underlying disease in six of the total of seven cases contrasts with the usual findings for other zygomycoses. This article describes all seven reported cases as well as the characteristics of this unique fungal pathogen.

Nosocomial Legionella micdadei pneumonia: 10 years experience and a case-control study.

Sixteen patients with nosocomial Legionella micdadei pneumonia, diagnosed between 1977 and 1988, were studied retrospectively to define clinical and epidemiological characteristics of the disease. Also, a case-control study was performed comparing the five patients with L. micdadei pneumonia during a cluster of cases in 1982, with uninfected patients with the same underlying diagnoses. No significant differences were noted in the case-control study with regard to age, presence of leucopenia, intensity or duration of immunosuppressive therapy, bed location, duration of hospital stay, frequency of transplant rejection or overall mortality. Legionella micdadei isolates from a sink on the renal transport ward, from hot water storage tanks, and one clinical isolate had identical cellular fatty acid composition. Extensive sampling of other potential sources failed to yield the organism. This indirect evidence suggests potable water as the source of infection.

Pneumonia treated with imipenem/cilastatin.

In an open, prospective, multicenter trial the efficacy and tolerance of imipenem/cilastatin for the treatment of bacterial pneumonia was investigated. Forty-three adults were studied: 29 with nosocomial and 14 with community-acquired infections. Significant underlying disease was present in 91 percent of patients. Nosocomial infection was frequently associated with endotracheal intubation (48 percent), prior antibiotic therapy (48 percent), and recent surgery (31 percent). Most frequent sputum isolates included Pseudomonas aeruginosa (10, all nosocomial), Hemophilus influenzae (10), Escherichia coli (eight), Staphylococcus aureus (seven), and Streptococcus pneumoniae (six). Treatment with imipenem/cilastatin was associated with clinical cure in 93 percent of patients. Two of three failures and one superinfection occurred in association with isolates of Pseudomonas aeruginosa resistant to imipenem. Overall, six of 10 strains of Pseudomonas aeruginosa isolated prior to therapy developed resistance to imipenem after an average of 10 days of therapy. Adverse effects occurred in nine patients (21 percent) and included one case of pseudomembranous colitis. Monotherapy with imipenem/cilastatin of serious lower respiratory tract infections was relatively safe and highly effective with the exception of disease associated with P. aeruginosa.

Anthrax toxin components stimulate chemotaxis of human polymorphonuclear neutrophils.

Effects of the three-component toxin of Bacillus anthracis on chemotaxis of human polymorphonuclear leukocytes (PMN) were investigated in an effort to determine the basis of the reported antiphagocytic effect of the toxin. The three toxin components, edema factor (EF), protective antigen (PA), and lethal factor (LF), were tested alone and in various combinations for their effect on PMN chemotaxis under agarose to formyl peptides and zymosan-activated serum. No component was active alone; combinations of EF + PA, LF + PA, and EF + LF + PA markedly stimulated chemotaxis (directed migration), but had little or no effect on unstimulated random migration. The toxin components were not themselves chemoattractants. EF in combination with PA had previously been identified as an adenylate cyclase in Chinese hamster ovary (CHO) cells. We found that EF + PA produced detectable cyclic adenosine 3'-5'monophosphate (cAMP) in PMN, but the level of cAMP was less than 1% of that produced in CHO cells by EF + PA, and in PMN by other bacterial adenylate cyclases. LF + PA (which stimulated chemotaxis to an equivalent extent) had no effect on cAMP levels. Thus, the enhancement of chemotaxis by anthrax toxin (at least by LF + PA) does not seem to be related to adenylate cyclase activity.

Interactions of Bacteroides fragilis and phagocytes: studies with whole organisms, purified capsular polysaccharide and clindamycin-treated bacteria.

Bacteroides fragilis plays a key role in the pathogenesis of anaerobic infections and is often found mixed with aerobic organisms. We explored the interactions of this organism with phagocytes in an attempt to discern additional information about its virulence factors. We confirm an earlier report that killing of aerobic organisms by polymorphonuclear leukocytes (PMN) is decreased in the presence of high numbers of Bact. fragilis but this effect could also be demonstrated with Bact. distasonis or Staphylococcus aureus. Our data support the concept that this phenomenon may be due to competition for opsonins. Virulence of Bact. fragilis has been associated with a polysaccharide capsule. We were unable to demonstrate any deleterious effect of the purified capsular polysaccharide of Bact. fragilis on phagocytosis, killing, or chemotaxis by PMN. We were not able to demonstrate any effect of subinhibitory levels of clindamycin on the interactions of neutrophils and Bact. fragilis.

Polymorphonuclear leukocytes: dedicated professional phagocytes.

Polymorphonuclear leukocytes are termed professional phagocytes because they are specially equipped to seek and destroy invading microorganisms. Polymorphonuclear leukocytes are formed in the bone marrow and released into the circulation, where they are transported to the tissues. At sites of tissue invasion by microorganisms, humoral factors are released that induce these cells to leave the bloodstream and enter the tissues. Chemotactic substances guide polymorphonuclear leukocytes to the infecting organisms. Antibody and complement can function as opsonins and enhance the ability of polymorphonuclear leukocytes to engulf microbes. Ingested organisms are killed by oxidative or nonoxidative systems. Defects in the various aspects of polymorphonuclear leukocyte function may be found in patients with recurrent, severe, or unusual infections. Evaluation of selected patients with recurrent infections should include tests of polymorphonuclear leukocyte function.

Exchange transfusion for sickle cell intrahepatic cholestasis.

Only one of eight previously described patients with sickle cell intrahepatic cholestasis (SCIH) survived. Death usually resulted from liver failure and/or a hemorrhagic diathesis. This report deals with the successful treatment of SCIH by partial blood-plasma exchange transfusion. This treatment led to regression of hepatic encephalopathy, impending bleeding diathesis, and noticeable clinical improvement withn 48 hours. Within six days, the serum bilirubin level decreased from 146 to 16 mg/dL. Partial blood-plasma exchange transfusion may be valuable for the treatment of SCIH.