Use of cefazolin for peritonitis treatment in peritoneal dialysis patients.

For over two decades, intraperitoneal administration of vancomycin and an aminoglycoside has been an accepted regimen for the empiric treatment of peritonitis in the peritoneal dialysis patient, until definite identification of the organism has been made. The recent emergence of vancomycin-resistant organisms has been of great concern in many centers. The current treatment recommendation therefore is to use cefazolin in place of vancomycin. We analyzed peritonitis data from January 1, 1996 to June 30, 1997, prior to switching over to cefazolin. Seventy-five percent (27 episodes) in 1997 as compared to 78% in 1996 were due to gram-positive organisms. Twenty-two percent (8 episodes) were due to gram- negative organisms in 1997, 21% in 1996, and 3% (1 episode) due to yeast in 1997, 3% in 1996. Staphylococcus epidermidis (SE) caused 33% of the gram-positive peritonitis episodes in 1997 as compared to 37% in 1996. Twenty-two percent of the gram-positive episodes were due to Staphylococcus aureus (SA) in 1997 and 46% in 1996. Enterococcal infections were 26% in 1997 and 1% in 1996. All of these were confined to only 1 patient. The antibiogram revealed 100% sensitivity of both SA and SE to vancomycin and 100% sensitivity of SA to cefazolin, but only 11% sensitivity of SE to cefazolin. The same patient population had a 48% sensitivity of SE to cefazolin in 1996, showing a sudden and substantial increase in resistance to SE. Even though SE is thought to be a less virulent organism, treating patients with a high probability of being infected by SE with an antibiotic showing 89% resistance is not warranted.

Pneumocystis carinii pneumonia diagnosed by non-induced sputum stained with a direct fluorescent antibody.

Non-induced expectorated sputum (NIS) stained with tinctorial stains is not considered useful in the diagnosis of Pneumocystis carinii pneumonia (PCP). The diagnostic yield of NIS was evaluated in human immunodeficiency virus (HIV)-infected patients, when stained with a more sensitive direct fluorescent antibody for PCP-direct fluorescent antibody (PC-DFA). A retrospective analysis was carried out on fifty-five HIV-infected patients with PCP, who had NIS submitted for staining with PC-DFA. Thirty had positive NIS with PC-DFA and all had clinical courses consistent with PCP. Twenty-five had negative NIS with PC-DFA and were diagnosed as having PCP, by autopsy (n = 2), by a positive bronchoalveolar lavage (n = 10), or by having a clinical course consistent with PCP (n = 13). Thus, the sensitivity of NIS stained with PC-DFA was 55 percent (30/55). This is within the range reported in the literature for induced sputum for the diagnosis of PCP. Non-induced sputum stained with PC-DFA can be useful for the diagnosis of PCP in HIV-infected patients.

Comparison of a new latex agglutination assay with indirect immunofluorescence to detect varicella-zoster antibodies.

A comparison of a latex agglutination assay with an immunofluorescence assay for the detection of varicella-zoster virus antibodies is described. The two tests were completely concordant in their results; therefore the latex agglutination test may be valuable for laboratories that require rapid turnaround time or have limited personnel and equipment.

Endophthalmitis caused by Enterobacter cloacae.

Cataract extraction with placement of intraocular lenses is the most common intraocular procedure done today, with endophthalmitis as its most devastating complication. To our knowledge, this is only the third reported case of postoperative endophthalmitis caused by the gram-negative bacillus, Enterobacter cloacae. The course of infection, the treatment, and the laboratory identification of this organism are presented. It is important to add this proven case of gram-negative endophthalmitis to our growing knowledge of causes of this disease because, despite aggressive treatment with vitrectomy and intravitreal antibiotics, the infection was so virulent that it led to eventual phthisis bulbi.

Enterobacter taylorae, a new opportunistic pathogen: report of four cases.

Severe nosocomial infections due to Enterobacter taylorae (formerly known as CDC Enteric Group 19) are described in four patients. Unlike most members of the Enterobacter genus, the isolates were not susceptible to penicillins or cephalosporins. Restriction endonuclease analysis of E. taylorae DNA obtained from three patients identified two distinct strains. One strain was found in two patients, suggesting a common source which we were not able to identify. We postulate that in patients harboring E. taylorae, the combination of cephalosporin therapy and instrumentation enables this organism to become an opportunistic pathogen.

Prevention of transfusion-associated cytomegalovirus infection in neonatal patients by the removal of white cells from blood.

The usual methods employed to reduce the risk of transfusion-associated cytomegalovirus (TA CMV) disease have been to transfuse blood or cellular blood components that are CMV antibody-negative or to administer deglycerolized frozen red cells. To determine if the reduction of white cells (WBCs) in blood by filtration will also eliminate TA CMV disease in a high-risk population, 48 surviving very low birth weight (less than 1250 g) neonatal infants born to CMV-seronegative mothers at three participating institutions in the Hartford, Connecticut area and receiving at least one CMV-seropositive blood transfusion were studied. The incidence of TA CMV disease in 26 neonatal patients who received blood prepared by a modified spin-cool-filter technique and in 22 neonatal patients who received blood filtered through a WBC-reduction filter was compared with the incidence of transfusion-associated disease in similar populations reported in other studies. The CMV antibody prevalence of the blood donor population was found to be 37 percent. At the time of discharge of the individual neonatal infants in the population studied, and/or 2 to 6 months later, 47 of the 48 who had undergone transfusion had CMV antibody-negative serologic tests and/or urine culture. The other infant transiently seroconverted because of passive transfer of the antibody. None of the 48 neonatal infants had clinical evidence of CMV infection. This study indicates that WBC reduction of donor blood can reduce and perhaps prevent TA CMV disease in high-risk neonatal patients.

Cytomegalovirus antibody detection in blood donors and mothers of very low birth weight neonates by using three serologic methods.

We compared three serologic methods for cytomegalovirus (CMV) antibody detection and determined the CMV antibody seroprevalence of blood donors and mothers of very low birth weight (less than 1250 g) neonates in the Greater Hartford region. CMV serology was determined for 577 healthy blood donors as well as for 147 mothers of premature infants. Plasma from blood donors and sera from mothers were tested by either latex agglutination (LA) or by an immunofluorescent antibody assay (IFA), and results were compared with those from an enzyme-linked immunosorbent assay (ELISA). Sensitivity and specificity for LA to ELISA were significantly better than for IFA to ELISA [sensitivity 79/81 (97%) vs 171/202 (85%), and specificity 90/94 (96%) vs 257/347 (74%), p less than 0.01]. These differences remained whether plasma or sera were tested. Borderline values explained only two (33%) of six LA-ELISA as well as only 70 (58%) of 121 IFA-ELISA discordance. CMV seroprevalence rate for the donor blood population was 38%, and for the mothers was 53%. The LA assay is superior to the IFA assay for CMV screening of blood donors and maternal populations.

Mycobacterium avium intracellulare as a marker of human immunodeficiency virus disease.

Between January 1981 and December 1986, 4,178 patients were cultured for mycobacteria at a community teaching hospital in Hartford. The number of patients with positive cultures totaled 278 (6.65%). Mycobacterium other than tuberculosis (MOTT) was isolated from 228 (82%). MOTT isolation increased yearly from 1.5% of the patients in 1981 to 14.5% of the patients in 1986. Mycobacterium avium intracellulare (MAI) was the most common MOTT species isolated (197/228). Fifty-nine patients were under the age of 50, but 23 had predisposing factors for MOTT. Of the 36 who did not have an underlying condition, 25 had the human immunodeficiency virus (HIV). The isolation of MAI preceded the diagnosis of AIDS/ARC in nine patients, in 10 others it coincided with their diagnosis and in six it followed the diagnosis. Isolation of MAI in a patient under the age of 50 with no predisposing factors may suggest concommitant HIV disease.

Acute arthritis in caprine arthritis-encephalitis virus challenge exposure of vaccinated or persistently infected goats.

Goats vaccinated with inactivated caprine arthritis-encephalitis virus (CAEV) developed more severe arthritis after infectious CAEV challenge exposure than did goats vaccinated with tissue culture medium. Arthritis also developed more rapidly in the group vaccinated with inactivated virus. In another experiment, goats with persistent CAEV infection developed acute arthritis after at least 2 injections of infectious CAEV at monthly intervals. In this experiment, the control group consisted of goats with persistent CAEV that were given tissue culture medium. Seemingly, the immune response to CAEV is an important cause of the CAEV-induced arthritis.

A sequential study of virus expression in retrovirus-induced arthritis of goats.

Persistent infection by the retrovirus caprine arthritis--encephalitis virus (CAEV) induces arthritis in goats which closely resembles rheumatoid arthritis. To examine the relationship between virus expression and development of clinical disease, ten goat kids were inoculated with CAEV and examined at successive intervals through 18 months post-infection. Virus was monitored in cell-free synovial fluid cells, serum and peripheral blood cells by titration, co-cultivation and immunofluorescent techniques. Virus was readily recovered from the synovial cavity of all animals during the first 4 weeks of infection, followed by a reduction and fluctuation in virus titres and ability to detect virus. Recovery of CAEV from peripheral blood cells occurred at low frequency while viraemia was rare. Results obtained over a period of 18 months indicate a positive association between virus expression in the synovial cavity and development of clinically detectable disease.

Immune rabbit sera do not recognize antigenic variants of caprine arthritis-encephalitis virus isolated during persistent infection.

Isolates of caprine arthritis-encephalitis virus recovered 12 to 18 months after infection of goats were tested for neutralization by using rabbit antisera directed to the original inoculum virus. Only slight differences in neutralization kinetics between the long-term isolates and the original virus were detected, indicating that heterologous rabbit antisera do not detect antigenic variation of the neutralizing epitopes of caprine arthritis-encephalitis virus.

Transmission and control of caprine arthritis-encephalitis virus.

Caprine arthritis-encephalitis virus was isolated from goat milk and transmitted most efficiently to kids through both milk and colostrum. In addition, it appeared that transmissions through other secretions of the doe occurred, but were less important than transmission in milk and colostrum. Intrauterine infection may have occurred in 2 of 32 cesarean-derived goats, but postpartum horizontal transmission could not be ruled out. Transmission by the aerosol route was not demonstrated, and even short-term direct contact between virus-infected bucks and virus-free does during breeding did not result in transmission. Prolonged direct contact for over 12 months between weaned cesarean-derived goats and virus-infected goats was necessary before horizontal transmission could be demonstrated under nondairy conditions. However, when uninfected does were milked with infected does, a high percentage became infected in less than 10 months. Heat inactivation (56 C) reduced approximately 10(5) median tissue culture infective doses of caprine arthritis-encephalitis virus to below titratable levels, and virus was not transmitted to kids fed virus-infected colostrum that had been heated at 56 C for 1 hour. A program of eradication is discussed in which kids are removed from their dams at birth, fed safe sources of colostrum and milk, and isolated from other goats until weaning.

Preferential immune response to virion surface glycoproteins by caprine arthritis-encephalitis virus-infected goats.

Six months after inoculation with caprine arthritis-encephalitis virus, the serum and synovial fluid of virus-infected goats had antibodies to [35S]methionine-labeled viral proteins with apparent molecular weights of 125,000, 90,000, 28,000, and 15,000. The 125,000-, 90,000-, and 15,000-molecular-weight methionine-labeled proteins were identified as virion surface glycoproteins by lactoperoxidase iodination and galactose oxidase-boro[3H]hydride reduction labeling techniques. Radioimmunoassay antibody titers to purified p28, the most abundant viral structural protein, averaged 1:182 in synovial fluid and 1:67 in serum 6 months after inoculation. High dilutions of serum and synovial fluid reacted with gp90 and gp125 electroblotted onto nitrocellulose paper from polyacrylamide gels. Anti-gp90 activity was detected at dilutions with an immunoglobulin G content of 0.02 to 11 micrograms, whereas antibody to p28, when detectable on Western blots, was present in samples with an immunoglobulin G content of 0.1 to 2 mg, representing 100- to 1,000-fold-greater titers of antibody to the surface glycoprotein. Synovial fluids often contained more anti-gp90 antibody than did sera. Immunoprecipitation of lactoperoxidase-iodinated virus confirmed the presence of high antibody titers to the two virion surface glycoproteins. Because antiviral gp90 and gp125 antibody is abundant in the synovial fluid of infected goats, it probably contributes to the high immunoglobulin G1 concentrations seen at this site 6 months after caprine arthritis-encephalitis virus infection.

Susceptibility of blood-derived monocytes and macrophages to caprine arthritis-encephalitis virus.

Permissiveness of blood-derived caprine monocytes to infection by caprine arthritis-encephalitis virus increased during in vitro cultivation and differentiation into macrophages, as evidenced by immunofluorescence and release of extracellular infectious virus. The degree of cell susceptibility to virus infection varied among individual goats, independent of age or breed. Caprine arthritis-encephalitis virus infection of macrophages in vitro resulted in no alteration of five characteristic functional activities.

Neutralizing antibody response of rabbits and goats to caprine arthritis-encephalitis virus.

Rabbits were immunized with purified caprine arthritis-encephalitis virus and examined for neutralizing activity. Analysis of virus-antiserum interaction at 37 degrees C demonstrated little loss of viral infectivity after incubation with heat-inactivated rabbit antiserum for 60 min. However, sensitization of virus (as assessed by the addition of complement) occurred almost immediately and was 95% complete after 10 min. The complement-dependent neutralizing activity was associated with the immunoglobulin G fraction of rabbit antiserum. Addition of goat anti-rabbit immunoglobulin G to the immune rabbit serum-caprine arthritis-encephalitis virus mixture also resulted in neutralization of infectivity when unbound antibody was removed before addition of the anti-immunoglobulin. Serum from most caprine arthritis-encephalitis virus-infected goats contains antibody activity to the core protein p28, as demonstrated by immunodiffusion and enzyme-linked immunosorbent assay. However, attempts to demonstrate neutralizing activity in the serum of goats up to 1.5 years post-inoculation or in serum of hyperimmunized goats were unsuccessful when the sera were examined alone or in combination with complement or rabbit anti-goat immunoglobulin or both.

Caprine arthritis-encephalitis virus is distinct from visna and progressive pneumonia viruses as measured by genome sequence homology.

Competitive inhibition of hybridization between (125)I-labeled caprine arthritis-encephalitis viral RNA and homologous cDNA by heterologous viral RNA shows that the caprine retrovirus shares <20% genome sequence homology with visna and progressive pneumonia viruses. These viruses, however, are indistinguishable in immunodiffusion reactions involving the major structural protein (p28).

Antigenic stimulation of T lymphocytes in chronic nononcogenic retrovirus infection: equine infectious anemia.

Equine infectious anemia is a chronic disease of horses caused by a nononcogenic retrovirus. Studies were undertaken to determine the types of cells involved in the in vitro lymphoproliferative response to viral antigens and the dynamics of this reaction. It was observed that reactive lymphocytes were present at unpredictable times in the peripheral blood of infected horses. This reaction was shown to be specific for the interaction of equine infectious anemia virus and T lymphocytes. Enriched B-lymphocyte populations did not divide when exposed to equine infectious anemia virus. Macrophages were depleted from the reaction by two methods: adherence to Sephadex and a combination of binding to Sephadex and adherence to complement-coated erythrocytes. Both methods reduced the number of monocytes, but only the combination of Sephadex and complement-coated cells removed the accessory cells needed for lymphocyte proliferation. We conclude that during the chronic stages of equine infectious anemia the number of antigen-reactive T lymphocytes fluctuates within the peripheral blood and that these cells require a complement-binding cell for reaction. The relationship of these cells to the lymphoproliferative stages of this disease is discussed.