Phase IIa trial of cilengitide (EMD121974) single-agent therapy in patients (pts) with recurrent glioblastoma (GBM): EMD 121974-009

2002

Background: Our phase IIa study evaluated the safety, toxicity, and clinical activity of the cyclic RGD pentapeptide cilengitide (EMD121974), an inhibitor of integrins avβ3 and avβ5, as a single agent at doses of 500 and 2000 mg in pts with recurrent GBM. Methods: In this multicenter, open-label, randomized, uncontrolled study, pts with GBM and measurable disease that had relapsed after previous temozolomide and radiotherapy were randomized to receive cilengitide at either 500 mg or 2000 mg i.v., 2x/week, until progression. Neurologic exams were performed after every cycle (4 weeks) and MRIs were performed every other cycle. Central, blinded pathology and radiology reviews were performed. The primary endpoint was Progression Free Survival (PFS) at 6 months (6-mth PFS). Secondary endpoints included response, survival, time to disease progression, safety, tolerability and pharmacokinetics (PK). Results: 81 pts accrued (median Karnofsky Performance Status 80%; median age 57 yrs) at 15 sites including 41 at the 500 mg and 40 at the 2000 mg dose levels. Demographic and pretreatment variables were comparable between dose level cohorts. The median number of infusions was 16 [range, 4–179]. PK studies revealed significantly greater exposures among the 2000 mg cohort. Treatment related NCI CTC grade 3 adverse events (AEs) included elevated transaminases (at 500 mg), arthralgia/ myalgia (at 500 mg), and weight increase/ edema (at 2000 mg) in 1 patient, respectively. No grade 4 therapy related AEs were reported. One CTC grade 2 cerebral hemorrhage was reported in a pt at progression. The 6- mth PFS was 16.1% (n=13/81 pts). 10 pts (12.3 %, n=4 with 500 mg, n=6 with 2000 mg) received 12 or more cycles. Six pts (7.4%) remain progression-free and on treatment. Median Overall Survival (mOS) was 6.5 mths [95% CI: 5.2–9.3 mths] in the 500 mg arm and 9.9 mths [95% CI, 6.3–15.7 mths] in the 2000 mg arm. Although not statistically significant, there was a trend towards better tumor control in pts receiving 2000 mg 2x/week. Conclusions: Cilengitide was well tolerated and demonstrated single agent activity in recurrent GBM, with long term disease stabilization in a subset of pts.

[Table: see text]

Development of a cytomegalovirus vaccine: lessons from recent clinical trials

Cytomegalovirus-caused diseases are preventable. We believe that both neutralising antibodies and cell-mediated immunity are necessary for prevention. Of the CMV proteins, gB and pp65 are the minimum requirements in a vaccine to induced neutralising antibodies and cytotoxic T-lymphocyte (CTL) responses. Immunisation with additional proteins, e.g., gH, gN for neutralising antibodies and IE1exon 4 and pp150 for CTL responses, would strengthen protective immune responses. Approaches to development of a safe and effective cytomegalovirus (CMV) vaccine for the prevention of CMV diseases include: a) a live attenuated vaccine (Towne strain); b) recombinant constructs of the attenuated Towne and the virulent Toledo CMV strains; c) subunit glycoprotein B (gB) adjuvanted with MF59 to induce neutralising antibodies; d) phosphoprotein 65 (pp65) peptide-based vaccines to induce (CTL) for use in therapeutic vaccination; e) canarypox-CMV recombinants, e.g., ALVAC-CMV(gB) and ALVAC-CMV (pp65) to induce neutralising antibodies and CTL responses, respectively; f) DNA plasmids containing the genes for gB and pp65; g) dense bodies containing the key antigens. The attenuated Towne strain, gB/MF59, ALVAC-CMV(gB) and ALVAC-CMV(pp65) approaches have already been tested in clinical trials. The Towne vaccine induced neutralising antibodies and cell-mediated immunity (including CTLs) mitigated CMV disease in seronegative renal transplant recipients and protected against a low-dose virulent CMV challenge in normal volunteers but did not prevent infection in mothers of children excreting CMV. Immunisation with gB/MF59 resulted in high levels of neutralising antibodies in seronegative subjects. ALVAC-CMV(gB) did not induce neutralising antibodies but primed the immune system to a Towne strain challenge, while ALVAC-CMV(pp65) induced long-lasting CTL responses in all originally seronegative volunteers, with CTL precursor frequency similar to naturally seropositive individuals. These results suggest that CMV diseases can be prevented or attenuated and that a vaccine combining ALVAC-CMV(pp65) with gB/MF59 may induce sufficient CTLs and neutralising antibodies to protect against CMV diseases. Meanwhile, other approaches such as DNA peptide and dense body vaccines, should enter Phase I trials. All candidate vaccines will have to demonstrate that immunogenicity provides protection. Combined vaccines containing canarypox (ALVAC) vectors to express CMV-pp65 to induce CTLs and of subunit gB, given together with an appropriate adjuvant to induce neutralising antibodies, should be tested in a target population for the prevention of CMV infection and disease.

A canarypox vector-expressing cytomegalovirus (CMV) phosphoprotein 65 induces long-lasting cytotoxic T cell responses in human CMV-seronegative subjects

The major matrix phosphoprotein 65 (pp65) of cytomegalovirus (CMV) is an important target of HLA-restricted cytotoxic T cells (CTL) after natural infection. A canarypox-CMV pp65 recombinant was studied for its ability to induce CMV pp65-specific CTL, helper T lymphocytes, and antibodies in a phase I clinical trial. Twenty-one CMV-seronegative adult volunteers were randomized to receive immunizations at months 0, 1, 3, and 6 with either canarypox-CMV pp65 or placebo. In canarypox-CMV pp65-immunized subjects, pp65-specific CTL were elicited after only 2 vaccinations and were present at months 12 and 26 in all subjects tested. Cell-depletion studies indicated that the CTL were phenotype CD8(+). Peripheral blood mononuclear cells proliferated in response to stimulation with purified pp65, and antibodies specific for pp65 also were detected. Canarypox-CMV pp65 is the first recombinant vaccine to elicit CMV-specific CTL responses, which suggests the potential usefulness of this approach in preventing disease caused by CMV.

Preparing for elimination of congenital Rubella syndrome (CRS): summary of a workshop on CRS elimination in the United States

The goal of eliminating indigenous rubella and congenital rubella syndrome (CRS) in the United States in the near future is now within reach, because rubella incidence has been sustained at record-low levels since the mid-1990s. Effective prevention strategies to eliminate CRS and rubella require improvement in the surveillance of CRS and congenital rubella infection (CRI). The purpose of the workshop was to review rubella and CRS epidemiology, as well as current clinical, diagnostic, and laboratory practices, to determine whether new strategies are needed to achieve and document CRS elimination. Workshop participants agreed that surveillance for CRS must be strengthened, particularly through augmented laboratory capabilities, and the case definition for CRS must be revised to reflect the current scientific information available. Further studies of methods are needed to identify high-risk populations and geographic areas for rubella and CRS and to enhance identification of infants with CRS.

Cytotoxic T lymphocyte (CTL) responses to human cytomegalovirus pp65, IE1-Exon4, gB, pp150, and pp28 in healthy individuals: reevaluation of prevalence of IE1-specific CTLs

The prevalence of human cytomegalovirus (HCMV) pp65-, pp150-, IE1-exon4-, gB- and pp28-specific cytotoxic T lymphocyte (CTL) responses was compared among 34 healthy individuals, grouped by neutralizing antibody titers. Moderately and highly seropositive donors showed predominantly pp65- and IE1-exon4-specific CTL responses (92% and 76% of the donors, respectively), with similar precursor frequencies in the 2 donors tested. In addition, highly seropositive and a few moderately seropositive donors showed CTL responses to gB and pp150 (33% and 30% of the donors, respectively). No individual recognized pp28 as a target in the CTL assay. Phenotypic analysis revealed a mixed effector population of CD4+ and CD8+ (1 donor) or only CD8+ cells for pp65-specific effectors (2 donors). IE1-exon4- and pp150-specific effectors were CD8+ (2 donors and 1 donor, respectively), whereas gB-specific CTLs were CD4+ (1 donor). These data may help to design a cellular immunity-based vaccine effective against HCMV diseases.

Lessons learned from a review of the development of selected vaccines. National Vaccine Advisory Committee

BACKGROUND

Although the vaccine research and development network in the United States remains vibrant, its continued success requires maintaining harmonious interaction among its many components. Changing one component is likely to affect the system overall. An examination of case studies of the development of selected vaccines would allow an examination of the network as a whole. This article presents conclusions drawn from the case study review undertaken.

OBJECTIVE

Successful development of vaccines is a time-intensive process requiring years of commitment from a network of scientists and a continuum of regulatory and manufacturing entities. We undertook this work to shed light on how well the vaccine development system in the United States performs.

METHOD

The National Vaccine Advisory Committee examined the research and development pathways of several vaccines that reached licensure expeditiously (hepatitis B vaccine, Haemophilus influenzae type b conjugate vaccines); some that became licensed only after considerable delay (oral typhoid Ty21a vaccine, varicella vaccine); some that are at the point of imminent or recent licensure (reassortant Rhesus rotavirus vaccine, which was licensed by the Food and Drug Administration on August 30, 1998) or near submission for licensure (intranasal cold adapted influenza vaccine); and one for which clinical development is slow because of hurdles that must be overcome (respiratory syncytial virus vaccines).

RESULTS

Some common themes emerged from the reviews of these vaccine "case histories": the expediting influence of a strong scientific base and rationale; the need for firm quantitation of disease burden and clear identification of target populations; the critical role played by individuals or teams who act as "champions" to overcome the inevitable obstacles; availability of relevant animal models, high-quality reagents and standardized assays to measure immune response; the absolute requirement for well designed, meticulously executed clinical trials of vaccine safety, immunogenicity, and efficacy; postlicensure measurements of the public health impact of the vaccine and a track record of the vaccine's safety and acceptance with large-scale use; and the critical need for international collaborations to evaluate vaccines against diseases of global importance that are rare in the United States (eg, typhoid fever). It was clear that the critical step-up from bench scale to pilot lots and then to large-scale production, which depends on a small group of highly trained individuals, is often a particularly vulnerable point in the development process.

CONCLUSIONS

One fundamental lesson learned is that within the varied and comprehensive US vaccine development infrastructure, multiple and rather distinct paths can be followed to reach vaccine licensure. The National Vaccine Advisory Committee review process should be conducted periodically in the future to ascertain that the US vaccine development network, which has been enormously productive heretofore and has played a leadership role globally, is adapting appropriately to ensure that new, safe, and efficacious vaccines become available in a timely manner.

Safety and immunogenicity of a live recombinant canarypox virus expressing HIV type 1 gp120 MN MN tm/gag/protease LAI (ALVAC-HIV, vCP205) followed by a p24E-V3 MN synthetic peptide (CLTB-36) administered in healthy volunteers at low risk for HIV infection. AGIS Group and L'Agence Nationale de Recherches sur Le Sida

A live recombinant canarypox vector expressing HIV-1 gpl20 MN tm/gag/protease LAI (ALVAC-HIV, vCP205) alone or boosted by a p24E-V3 MN synthetic peptide (CLTB-36) was tested in healthy volunteers at low risk for HIV infection for their safety and immunogenicity. Both antigens were well tolerated. ALVAC-HIV (vCP205) induced low levels of neutralizing antibodies against HIV-1 MN in 33% of the volunteers. None of them had detectable neutralizing antibodies against a nonsyncytium-inducing HIV-1 clade B primary isolate (Bx08). After the fourth injection of vCP205, CTL activity was detected in 33% of the volunteers and was directed against Env, Gag, and Pol. This activity was mediated by both CD4+ and CD8+ lymphocytes. On the other hand, the CLTB-36 peptide was poorly immunogenic and induced no neutralizing antibodies or CTLs. Although the ALVAC-HIV (vCP205) and CLTB-36 prime-boost regimen was not optimal, further studies with ALVAC-HIV (vCP205) are warranted because of its clear induction of a cellular immune response and utility as a priming agent for other subunit antigens such as envelope glycoproteins, pseudoparticles, or new peptides.

Clinical comparison of preinjection anesthetics

To minimize injection anxiety and discomfort, the podiatric surgeon can choose from a variety of topical anesthetics. Available modalities include skin refrigerants (also referred to as vapocoolants), needleless injection systems, iontophoresis, and eutectic mixtures of topical anesthetic cream such as EMLA Cream. Many of the vapocoolants contain chlorofluorocarbons, which are known to damage the ozone layer, a stratospheric layer that filters out harmful ultraviolet B radiation. In accordance with the 1992 Montreal Protocol, which banned the manufacture of certain chlorofluorocarbon compounds, many commonly used vapocoolants will no longer be available. Some newly marketed vapocoolants produce extremely cold temperatures, limiting their use. This article discusses the properties of various vapocoolants and other topical anesthetics and compares their effectiveness in patient trials.

St. Thomas Immunization Initiative. A student-run community action project

The objectives of the St Thomas Immunization Initiative are to provide a clinical community medicine experience for first- and second-year medical students, expose students to a community immunization program, teach students the principles of a community immunization program, and demonstrate a working relationship between the residents of an underserved community and medical students. From 1993 to 1995, first- and second-year students at Tulane University Medical School participated in class projects known as Shots for Tots and the St Thomas Immunization Initiative. Students received instruction about immunizations and administered vaccinations to children and adults in low-income neighborhoods. A total of 754 immunizations were administered to 331 children from 1993 to 1995. Participating students were surveyed and 82% of those who responded to a questionnaire felt that the project benefited the community it served while 79% felt that they personally benefitted from participating in the project. Given their experience, 96% of the students would be more likely to participate in a community development project in the future.

Case presentation of calcaneonavicular coalition in monozygotic twins

A case study of monozygotic twins with bilateral calcaneonavicular coalitions is presented. With the frequency of tarsal coalitions being approximately 1% to 2% and the frequency of monozygotic twins being 0.4%, it is a rare but predictable finding to see monozygotic twins with tarsal coalitions. This sheds additional light on the etiology of tarsal coalition that historically has been believed to be a defect in mesenchymal differentiation with indications of a genetic component. Despite the limited number of subjects used for various studies, tarsal coalitions have been considered to be an autosomal dominant defect with variable penetrance. In fact, inheritance of tarsal coalitions is more complicated than simple mendelian inheritance patterns and is likely to be a single error in a polygenic system. Because of this inheritance pattern, it is important to consider evaluating siblings and close family members of patients diagnosed with a tarsal coalition.

Inactivated poliovirus vaccine: past and present experience

Many countries have made use of inactivated poliovirus vaccine (IPV) in their national poliovirus control programs since 1955. Until 1961 IPV was the only vaccine available for the control of poliovirus, but subsequently many countries opted to use the Sabin attenuated poliovirus vaccine (OPV), which was perceived as more effective in preventing intestinal infection and in ensuring community protection by spreading to unvaccinated contacts of vaccinees. Nevertheless, IPV has remained the vaccine of choice in several countries, where experience has shown that it represents a safe and effective option for disease control. IPV limits subsequent infection of the pharynx and intestine in vaccinees, and is able to control circulation of poliovirus in a vaccinated population, providing effective community protection. Furthermore IPV contains only killed virus and cannot cause vaccine-associated paralytic poliomyelitis as OPV sometimes does. This paper reviews the history of the use of IPV, with emphasis on its efficacy and its ability to safely protect communities in which it is used. As the incidence of poliomyelitis declines new control strategies should take account of the knowledge of the use of poliovirus vaccines acquired since 1955.

Human safety and immunogenicity of a canarypox-rabies glycoprotein recombinant vaccine: an alternative poxvirus vector system

Avian poxvirus recombinants undergo abortive replication in nonavian cells, yet can achieve expression of extrinsic gene products. Canarypox-vectored vaccines have been innocuous and immunogenic in several mammalian species. ALVAC-RG, a canarypox recombinant expressing the rabies glycoprotein gene, was inoculated intramuscularly into adult volunteers on days 0, 28, and 180. Sequential cohorts received 10(3.5), 10(4.5), and 10(5.5) 50% tissue culture infective doses (TCID50); additional volunteers received the standard human diploid cell rabies vaccine (HDCV) on the same schedule. Reactogenicity of ALVAC-RG was minimal. The lowest dose of ALVAC-RG induced little antibody to rabies virus by ELISA or rapid fluorescent focus inhibition test (RFFIT), but 10(4.5) and 10(5.5) TCID50 doses elicited significant responses in both assays. All recipients of 10(4.5) and 10(5.5) TCID50 of ALVAC-RG attained RFFIT values above the presumed protective level. Canarypox-specific immune responses did not inhibit boosting of rabies-specific antibodies by the day 180 dose of ALVAC-RG. T cell proliferation in response to inactivated rabies virus in vitro was similar in HDCV and ALVAC-RG recipients after the first and second doses, although HDCV yielded superior results after the third dose. ALVAC-RG was safe in humans, induced functional antibody to rabies glycoprotein, elicited cellular responses to rabies virus, and could be used successfully for booster dosing at a 6 month interval.

[Vaccination perspectives]

The aim of vaccinology is to improve the available vaccines and to develop new ones in the light of progress in immunology, molecular biology and biotechnologies. But it must go beyond this, and aim to protect all populations and control diseases, even eradicate them where possible. New vaccine strategies must be developed taking into account the epidemiology of diseases and the inherent logistic problems of implementing these strategies under local conditions. There are three major thrusts to the progress of the discipline. The improvement of the vaccines available. One of the drives of vaccinology is not only to deliver vaccines of increasing safety (replacement of the current vaccine for whooping cough with an acellular vaccine for example), but also to improve vaccine efficacy and immunogenicity (in particular for flu, tuberculosis, cholera and rabies vaccines). The optimisation of vaccination programmes and strategies for vaccinations. The ideal is to protect against the greatest possible number of diseases with the smallest number of vaccinations. The development of combinations of vaccines is central to this goal. The objective for the year 2000 is a hexavalent vaccine DTPP Hib HB. The development of new vaccines. Classic techniques continue to be successfully used (inactivated hepatitis A vaccine; attenuated live vaccines for chicken pox and dengue fever; conjugated polyosidic bacterial vaccines for meningococci and Streptococcus pneumoniae). However, it will become possible to prepare vaccines against most transmissible diseases using genetic engineering techniques.(ABSTRACT TRUNCATED AT 250 WORDS)

Efficacy and safety of a Haemophilus influenzae type b capsular polysaccharide-tetanus protein conjugate vaccine

A polyribosylribitol phosphate (polysaccharide)-tetanus protein conjugate vaccine (PRP-T) against Haemophilus influenzae type b (Hib) was evaluated for safety and efficacy after vaccination of more than 100,000 infants. No major side effects were attributed to the vaccine. Immunogenicity studies showed an antibody response in 70% to 100% of infants after two doses, and in 98% to 100% of infants after three doses, within the first 6 months of life. Antibodies persisted in 90% of recipients, in whom significant anamnestic responses developed after a booster dose at 18 months of age. In comparison with other available Hib vaccines, PRP-T induces equal or higher mean titers after three doses. Although licensure of other vaccines interrupted controlled efficacy trials, up to that point five cases of Hib disease in those trials had occurred in placebo recipients, and no Hib disease has been reported in the more than 100,000 vaccinated infants who have received more than one dose of PRP-T. Thus PRP-T combined immunogenicity early in life with induction of immunologic memory.

Safety and immunogenicity of acellular pertussis vaccine combined with diphtheria and tetanus toxoids in 17- to 24-month-old children

A double-blind, randomized, controlled trial comparing 4 lots of acellular pertussis-diphtheria tetanus toxoids vaccine (APDT) to whole cell DTP vaccine in 397 children was conducted at 7 clinical centers. Children were immunized at 17 to 24 months of age and sera were obtained pre- and postimmunization. Sera were analyzed for antibody to pertussis antigens (pertussis toxin, filamentous hemagglutinin, with a molecular weight of 69,000 (69k) outer membrane protein and agglutinogens) and to diphtheria and tetanus toxoids. Information concerning local reactions and systemic events was collected daily for 10 days postimmunization. The acellular vaccine produced significantly fewer local reactions than whole cell DTP. Parents reported that drowsiness or fretfulness occurred significantly less often in APDT vaccine recipients compared with whole cell DTP recipients. Fever greater than or equal to 38.3 degrees C occurred in 8% of APDT vaccine recipients and in 15% of whole cell DTP vaccine recipients (P = 0.06). The only significant difference in immune response to pertussis antigens between the two vaccines was for filamentous hemagglutinin (P less than 0.01) for which significantly higher antibody concentrations were found in the APDT vaccine group. We conclude that this APDT vaccine is safe and immunogenic when administered as a booster dose to 18-month-old children.

Immunisation with canarypox virus expressing rabies glycoprotein

Poxviruses have many useful features as vectors for genes that carry immunising antigens from other viruses, such as ease of production and induction of cellular and humoral immunity, but there is concern about the safety of vaccinia virus. We turned to an avian poxvirus (canarypox); this virus undergoes abortive replication in mammalian cells that enables presentation of early gene products to the immune system. Canarypox virus was used as a vector for the rabies glycoprotein G gene. The safety and efficacy of the recombinant (ALVAC-RG; vCP65) were tested in several animal species, then it was subjected to a phase 1 clinical trial. Twenty-five volunteers were randomly assigned to subcutaneous injections of the recombinant (three groups [A, B, and C] received two doses each of 10(3.5), 10(4.5), and 10(5.5) tissue-culture infectious doses50, respectively) or of human diploid cell culture vaccine (HDC; 6.52 international potency units per dose). 28 days after the second dose, all nine ALVAC-RG group-C subjects and two of three group-B subjects had rabies neutralising antibody concentrations of at least 0.5 IU/ml, the level associated with protection in animals. Although the geometric mean titre of these antibodies at that time was lower in group C than in the ten HDC recipients (4.4 [range 0.9-12.5] vs 11.5 [4.7-25.3] IU/ml), a single booster dose at 6 months induced a recall response in volunteers primed with either vaccine. Side-effects associated with ALVAC-RG were mild and of short duration and occurred at similar frequency to those of HDC vaccine. This study has shown the potential of non-replicating poxviruses as vectors for vaccination in human beings. Trials of canarypox-virus recombinants at higher doses and by other routes of administration are needed.

Generation of deletion mutants of simian immunodeficiency virus incapable of proviral integration

Deletion mutants of simian immunodeficiency virus (SIVmac) which were unable to integrate into host cells were generated by removing a portion of the integrase (IN) domain of the pol gene. The resulting plasmid was transfected into HUT-78 and human rhabdomyosarcoma cells. In comparison with the parental plasmid DNA transfected in parallel, the deletion mutant was found to direct efficient production of virus in both cell systems. Viruses derived from wild-type and mutant proviral DNAs were also tested for their relative replicative abilities in HUT-78 and U937 cells, and the kinetics of virus production was found to vary between these two cell systems. Analysis of DNA from infected cell nuclei showed that the deletion mutant lacked the ability to integrate despite being able to produce infectious virus. Using the sensitive polymerase chain reaction technique, we have clearly demonstrated the absence of the IN domain in the deletion mutant after infection and replication in HUT-78 cells. Such mutants might form the basis for the development of an experimental live attenuated vaccine.

High expression of human cytomegalovirus (HCMV)-gB protein in cells infected with a vaccinia-gB recombinant: the importance of the gB protein in HCMV immunity

The human cytomegalovirus (HCMV), Towne strain, glycoprotein B (gB) gene was cloned into a vaccinia vector (Copenhagen strain) under the control of the H6 early and late vaccinia promoters (Vac-gB recombinant). The gB protein was expressed in a high percentage of the Vac-gB-infected cells throughout the virus replication cycle. Cytosine-arabinoside (ara-C) did not influence the expression of the gB protein early after infection (5 h), but did inhibit it later in viral replication (7-29 h). The Vac-gB recombinant induced HCMV neutralizing antibodies in guinea-pigs. Cells infected with the Vac-gB recombinant absorbed 50-88% of neutralizing activity of human sera obtained from volunteers previously inoculated with the Towne or Toledo strains and from naturally seropositive individuals.

Distribution of bacteria in the operating room environment and its relation to ventricular shunt infections: a prospective study

In order to study the distribution of bacteria in the operating room environment, cultures were obtained during 111 unselected shunt operations throughout a 10-month period. After routine skin preparation, bacteria were collected by placing Millipore filters on the patient's prepped skin underneath the drapes, on top of the drapes in the operative field, and/or on the sterile instrument table, and left in place for the duration of the case. In 48 patients, full-thickness skin biopsies taken at the initial incision were cultured in lieu of skin surface cultures. Perioperative cerebrospinal fluid cultures and subsequent shunt infections were monitored. Of the 288 environmental (skin and surfaces) cultures, 24 were positive (20 coagulase-negative Staphylococcus and 4 Staphylococcus aureus). Positive cultures were found in 15 of 111 drape cultures (13.5%), 7 of 77 instrument table cultures (9.1%), and 2 of 97 skin cultures (2.1%). Positive environmental cultures were not correlated with the surgeon, length of case, time of day, or type of shunt operation, but were more likely to occur in a room other than the designated neurosurgical operating room. There was a correlation between the occurrence of positive environmental cultures and positive cerebrospinal fluid cultures, although the organisms were not always the same. Coagulase-negative Staphylococcus was the most common organism isolated from all sites. We conclude that bacteria most often associated with shunt infections are airborne in the operating room, rather than originating from the patient's skin, and are distributed in the highest concentration near the surgical team.(ABSTRACT TRUNCATED AT 250 WORDS)