Q fever. A call to heighten our index of suspicion.

The prevalence of Q fever infection is probably underestimated. In Michigan, the first two reported human cases of Q fever occurred in 1984. The case-patients lived in adjacent, rural counties and had multiple exposures to goats. We conducted a serosurvey of goat owners and a reference population to compare the prevalence of Q fever antibodies in the two-county area. Goat owners were almost three times more likely to be seropositive with Q fever antibodies than the reference population (43% vs 15%). Among goat owners, individual and household seropositivity prevalences were positively correlated with the number of goats, the number of positive goats, and the number of goat births on the farm. Q fever should be considered more often in the differential diagnosis of patients with compatible illness, especially those with frequent animal contact.

Legionella feeleii-associated pneumonia in humans.

Legionella feeleii has been implicated by serologic studies as the causative agent in an outbreak of Pontiac fever and has been recovered from an institutional water source. Pneumonia caused by this agent has not been described previously. The authors have isolated L. feeleii from two immunosuppressed patients with community-acquired pneumonia and from an institutional water source. One patient survived after treatment with erythromycin. The other patient was leukopenic and died of pneumonia. Isolates exhibited typical cultural and biochemical features of L. feeleii and reacted with L. feeleii serogroup 1 antiserum. L. feeleii serogroup 1 is now known to cause not only Pontiac fever but also pneumonia in humans.

Jamestown Canyon virus (California serogroup) is the etiologic agent of widespread infection in Michigan humans.

In a sample population of 780 Michigan residents tested for neutralizing antibodies to California serogroup viruses, 216 (27.7%) had specific neutralizing antibody to Jamestown Canyon virus. An additional eight (1.0%) had specific neutralizing to trivittatus virus; none had specific neutralizing antibody to La Crosse virus. Significantly more male residents than female residents of the Lower Peninsula had antibody to Jamestown Canyon virus. The frequency of neutralizing antibody titers fits the Poisson distribution, suggesting that Jamestown Canyon virus infections occur endemically in residents of Michigan. Among 128 sera with specific neutralizing antibody to Jamestown Canyon virus, only two (1.6%) were found to have significant hemagglutination-inhibiting antibody titers with La Crosse virus, while 23 of 44 (52%) had significant titers with Jamestown Canyon virus; a single serum had significant antibody by complement fixation tests with both La Crosse and Jamestown Canyon viruses. This study confirms earlier speculation that complement fixation and hemagglutination-inhibition tests with La Crosse virus (the only tests for California serogroup virus infections performed by most state diagnostic laboratories) fail to detect antibody to Jamestown Canyon virus. ASPEX computer-drawn maps demonstrated that the distribution of persons with antibody to Jamestown Canyon virus and residing in Michigan's Lower Peninsula is closely correlated with the estimated distribution of white-tailed deer in that part of the state, further supporting the hypothesis that white-tailed deer are the primary vertebrate host for Jamestown Canyon virus.

Diagnostic efficacy of a DNA probe in pneumonia caused by Legionella species.

A commercial DNA probe kit (Gen-probe) for the detection of rRNA from legionellae was evaluated for its accuracy in diagnosing Legionnaires' disease in 167 patients with pneumonia. The test was performed on freshly obtained clinical respiratory tract samples. Cultures and direct immunofluorescence antibody (DFA) staining of the samples and serological tests were performed simultaneously for all patients. The probe assay result was positive in six patients; five of them had other laboratory evidence of disease (positive cultures or positive serological results or both). Depending on the diagnostic criteria, the probe test had a sensitivity of 31-67%, a specificity of 99% and positive predictive values of 67-83%. The diagnostic performance of the DNA probe assay in this study was superior to that of the DFA test. The results indicate that the examination of respiratory tract secretions by the Gen-probe kit is a suitable screening test for the diagnosis of Legionnaires' disease.

Respiratory syncytial virus infection: a cause of respiratory distress syndrome and pneumonia in adults.

Respiratory syncytial virus (RSV) infection, an important and sometimes lethal disease of infants and children, generally causes a milder and self-limited syndrome of cough, nasal congestion and fever in adults. While some evidence suggests that RSV may be responsible for more serious respiratory illness in the elderly and chronically ill, it has not been shown to cause life-threatening respiratory tract disease in previously healthy adults. This report describes a previously healthy woman who experienced the acute onset of right lower lobe pneumonia which rapidly progressed to the adult respiratory distress syndrome (ARDS). Acute and convalescent serology showed RSV was the cause of the respiratory tract illness. Michigan Department of Public Health records revealed six additional cases of adult bilateral pneumonia with diagnostic antibody titers to RSV, with or without coinfection with a second organism. These data suggest that RSV may be an under-recognized cause of lower respiratory tract disease in adults.

Use of gentamicin in the isolation of subgroup A Chlamydia.

The use of gentamicin to control contamination in a tissue culture system for the isolation of Chlamydia was investigated. Gentamicin, at concentrations up to 100 mug/ml, did not appear to inhibit the growth of stock chlamydial strains, as judged by assays for iodine-staining inclusions. When 343 cervical and urethral specimens were examined in the presence and in the absence of gentamicin, significantly more isolations of chlamydiae were obtained in the presence of 10 mug of gentamicin/ml, and significantly fewer unsatisfactory results due to contaminating organisms were seen. Therefore, this aminoglycoside antibiotic appears to be a useful addition to a cell system for isolation of Chlamydia.

Freezing and rejuvenation of human O erythrocytes for use in the immune adherence hemagglutination test.

A method was established to freeze selected human O erythrocytes and to thaw them as necessary for use in the immune adherence hemagglutination test. This method ensured interrun reproducibility and eliminated the necessity to screen blood donors (fresh cells) for acceptable C3b receptor site sensitivity.

Studies of the specificity of Legionella serology.

Sera with concurrent rises in titer to Legionella and mycoplasmal or chlamydial antigens were absorbed with whole Legionella organisms. Absorption removed Legionella reactivity only. No evidence of cross-reactivity between Legionella organisms and either Mycoplasma or Chlamydia organisms was found in studies of hyperimmune rabbit antisera.

Isolation of Chlamydia trachomatis by use of 5-iodo-2-deoxyuridine-treated cells.

Irradiated McCoy cells have provided a useful technique for the isolation of Chlamydia trachomatis strains, among which are found the etiological agents of trachoma, inclusion conjunctivitis, and lymphogranuloma venereum. Because irradiation is not always readily available, 5-iodo-2-deoxyuridine (IUDR) treatment of cells was investigated as a substitute procedure. IUDR-treated cells were found to be as sensitive to C. trachomatis infection as were irradiated McCoy cells. Stock chlamydial strains gave similar titers of iodine-stained inclusions in either system. When cells treated with IUDR were compared with irradiated cells for the isolation of C. trachomatis from clinical specimens, 5 of 138 specimens yielded isolates in IUDR-treated cells not found in irradiated ones, and one isolate was obtained from irradiated but not from IUDR-treated cells. In those 56 cases where inclusions were seen in both systems, there were significantly more inclusions in IUDR-treated than in irradiated cells. Although this series of cultures is too small to determine whether IUDR-treated cells are superior to irradiated ones for the isolation of C. trachomatis, the data indicate that IUDR treatment is at least equally effective.

Efficiency of plating on chick embryo cells and kinetic neutralization of Herpesvirus hominis strains.

Since it appeared that plaque formation in monolayers of primary chick embryo cells might provide a simple technique for the typing of Herpesvirus hominis strains, 100 isolates were tested for their efficiency of plating (EOP) on chick embryo cells versus plating on human embryonic fibroblasts. EOP values varied from 10(0) to 10(-6): 88% of the strains of genital origin had an EOP equal to or greater than 10(-2), and 82% of the oral isolates had an EOP equal to or less than 10(-3). Kinetic neutralizations were done with 53 strains, including those 12 with an EOP of 10(-2) or 10(-3). An estimate of antigenic relatedness (R(a)) between strains was calculated from the neutralization results. Although the site of recovery, EOP, and R(a) generally correlated, the EOP of some oral strains did not agree with the neutralization results, and some genital strains showed type 1 EOP and R(a) values. Selection of variants with increased EOP values did not result in accompanying changes in R(a). Thus, the two markers appeared to vary independently. These data support other findings which suggest that there may be no absolute correlation between biological and antigenic markers in herpesviruses and that a larger number with more diversity of strains should be examined for more markers before a typing system is established.

Isolation of Legionella species from drinking water.

Three different species of Legionella were recovered from samples of water taken from chlorinated public water supplies where no coliform bacteria were simultaneously detected. Five of 856 samples yielded Legionella isolates. Three isolates were identified as Legionella pneumophila serogroup 1, the fourth was identified as Legionella dumoffii, and the fifth was identified as Legionella jordanis. Studies to determine the survival of L. pneumophila Flint 1 serogroup 1 in tap water at various temperatures and in tap water with added sodium hypochlorite were done. These organisms were found to survive for 299 days in tap water at 24 and 5 degrees C but not at 35 degrees C. A concentration of at least 0.2 mg of residual chlorine per ml was required to eliminate at least 90% of L. pneumophila and Escherichia coli inocula in 2 h.

Antigenic relatedness of 17 strains of human cytomegalovirus.

A 10 minute kinetic neutralization test was used to assess antigenic relatedness among 17 strains of human cytomegalovirus. Hyperimmune guinea pig sera exhibited extensive cross-reactivity. However, the data did suggest that there may be four antigenic groups represented in this collection of CMV strains. Available epidemiologic data for these strains do not provide any discernible basis for this grouping.

Prevalence of Staphylococcus aureus, phage type 29/52/80, in Michigan.

Staphylococcus aureus, phage type 29/52/80, caused an outbreak of infections in Michigan over a period of two years and continues to be the most prevalent type seen. Of 3,752 isolates typed in 1980-81, 25 per cent were this phage type, which was strongly associated with methicillin resistance. Using this phage type as an indicator, we could demonstrate the spread of methicillin resistant staphylococci from Detroit metropolitan hospitals to suburban and, to a lesser extent, to hospitals outside the Detroit area.

In vitro antibacterial activity of trospectomycin (U-63366F), a novel spectinomycin analog.

Trospectomycin (U-63366F) is a novel spectinomycin analog with broad-spectrum antibacterial activity. The in vitro activity of this analog was compared with that of spectinomycin and other reference antibiotics against 411 clinical isolates of aerobic and anaerobic bacteria. MICs were determined by agar or broth dilution methods. The stability of trospectomycin in the presence of an enzyme extract derived from spectinomycin-resistant Escherichia coli was determined. Trospectomycin was more active than spectinomycin (4- to 32-fold) against strains of numerous bacterial species, including staphylococci, streptococci, Haemophilus influenzae, Branhamella catarrhalis, Neisseria gonorrhoeae, Proteus species, Bacteroides species, Clostridium difficile, Clostridium species, and Chlamydia trachomatis. Trospectomycin demonstrated a moderate level of activity (comparable to that of spectinomycin) for most species of the family Enterobacteriaceae tested and was generally cross resistant with spectinomycin. Trospectomycin was susceptible to inactivation by crude enzyme preparations from spectinomycin-inactivating strains of E. coli. Trospectomycin inhibited a variety of clinically important organisms, including agents of sexually transmitted diseases and pelvic inflammatory disease. Clinical studies with this novel aminocyclitol antibiotic are in progress.

Comparison of Transgrow and Gonozyme for the detection of Neisseria gonorrhoeae in mailed specimens.

The Transgrow culture system and Gonozyme (Abbott Laboratories, North Chicago, Ill.), an enzyme-linked immunosorbent assay procedure, were compared by examining 510 patients (320 females, 190 males) from whom duplicate genital swabs were obtained for the diagnosis of Neisseria gonorrhoeae infection. Both Transgrow and the Gonozyme swabs were mailed to the laboratory. Clinical, epidemiological, and laboratory data for the 30 specimens for which there were discrepancies were evaluated to determine the probability of gonorrhea. At the same time, Gonozyme was compared to on-site Thayer-Martin cultures from 258 of the 510 patients, with a 93% agreement. When sensitivity and specificity were calculated on the basis of clinical, epidemiological, and on-site laboratory data, Gonozyme had a sensitivity of 95% and a specificity of 99%. Transgrow culture was considered to have a 100% specificity and a sensitivity of 69%. Gonozyme appeared to be a superior method for the diagnosis of gonorrhea by means of mailed specimens.

Prevalence of antibodies to Legionnaires' disease. A seroepidemiologic survey of Michigan residents using the hemagglutination test.

The indirect fluorescent antibody test and a microhemagglutination technique detected antibodies in human sera to Legionnaires' disease antigen about equally. Since the hemagglutination technique was simpler, more rapid, and less expensive, we used it to ascertain the prevalence of antibody in 1200 sera from apparently healthy, nonhospitalized Michigan residents. Prevalence was analyzed by age, sex, geographic location (county or residence), and season of the year. There was a significant difference in prevalence between seasons: 91 of 600 sera (15.2%) from February to March 1978 had a titer equal to or greater than 1.16, contrasted with 179 of 600 sera (29.8%) from August to September 1978. This difference was independent of age and sex. There was no significant difference by geographic location, sex, or age except for decreased prevalence for persons 60 years or older.

Impact of swine influenza vaccine on serum antibody.

Comparison of a 1976 serum survey with one of 1977 has permitted an assessment of the impact of the national swine influenza vaccine program of 1976-1977 on the antibody status of the Michigan population. Prevalence of HI influenza virus antibody in premarital sera collected in 1976 prior to the vaccine program was compared to that in similar sera collected in 1977. Overall prevalence of A/New Jersey antibody (titers greater than or equal to 1:10) in 1976 sera was 22.3%. Little antibody was detected in sera from persons less than 40 years of age and prevalence peaked at age 50. Increased antibody prevalence was found for all age groups in sera collected in 1977 following the vaccine program, and the overall prevalence was 41.6%. Only 3.5% of those under 19 years of age were vaccinated, and post-vaccine prevalence for this group was 10%. This age group, comprising about 30% of the state population, appears to have had least exposure to swine influenza virus, and may be the population segment at greatest risk of infection should strains of this antigenic composition reappear. In contrast, highest prevalence of A/Victoria antibody was found in the 15 to 19 age group, where prevalence was 52%, compared to an overall prevalence at 40%.

Evaluation of an indirect hemagglutination test for Legionella pneumophila serogroups 1 to 4.

Parallel testing of 895 sera by indirect hemagglutination and indirect fluorescent-antibody techniques showed 97.3% agreement. Although the indirect hemagglutination technique usually showed more cross-reactivity among serogroups than the indirect fluorescent-antibody technique with Formalin-fixed antigens and a conjugate which detected primarily immunoglobulin G antibodies, heterologous serogroup reactions were significantly lower than homologous serogroup titers and the etiological serogroup could be easily defined. The indirect hemagglutination techniques showed no cross-reactivity with a crude extract of Escherichia coli O13:K92:H4. Since the indirect hemagglutination technique was shown to detect both immunoglobulin M and immunoglobulin G antibodies and was found to be rapid, simple, and inexpensive, it appears to be an excellent alternative to the indirect fluorescent-antibody test for serodiagnosis of legionellosis.

Comparison of Thayer-Martin, Transgrow, and Gonozyme for detection of Neisseria gonorrhoeae in a low-risk population.

The Gonozyme test (Abbott Laboratories, North Chicago, IL) an enzyme-linked immunosorbent assay procedure, on-site Thayer-Martin cultures, and Transgrow cultures were compared for sensitivity and specificity in detecting gonorrhea. For these comparisons triplicate genital swab specimens were obtained from women for the diagnosis of infection with Neisseria gonorrhoeae. Both the Transgrow and the Gonozyme specimens were mailed to a public health laboratory. The population under study was considered to be low-risk. When sensitivity and specificity were calculated on the basis of results of Thayer-Martin cultures, Transgrow had a sensitivity of 57% and a specificity of 100%. Gonozyme had a sensitivity of 80% and a specificity of 99%. In a low-risk population, the predictive value of a positive Transgrow culture was 100%, whereas the predictive value of a positive Gonozyme test was 57%. The predictive value of a negative Transgrow result was 99.7%, and that of a negative Gonozyme test was 99.8%. It is concluded that the use of the Gonozyme procedure for screening of low-risk populations needs further evaluation.