Surveillance of penicillin-resistant Streptococcus pneumoniae in one American metropolitan area, 1989-1998.

The emergence of invasive penicillin-resistant (PRSP) and multidrug-resistant (MDRP) Streptococcus pneumoniae was tracked from 1989 to 1998 in one medium-sized metropolitan area in the USA, encompassing western West Virginia, including Huntington, the only major city, and neighboring sections of Kentucky and Ohio. Capsular serotyping and antibiotic sensitivity tests were performed on 350 community-acquired isolates comprising 93.1% of all pneumococcal isolates identified. The incidence of PRSP increased from 3 to 10% during the 10 years of the study. Twenty-nine (22.1%) of 131 isolates of serotypes 6, 9, 14, 19, and 23 were PRSP (one-fourth were MDRP) and 1 (0.5%) of 219 other serotypes was PRSP (serotype 35). Invasive PRSP occurred most frequently in young children and in adults aged 80 years and older, 8.9 and 10.9 cases per 100,000 persons, respectively.

A 20-year epidemiological study of pneumococcal meningitis.

We conducted a retrospective analysis of 55 community-acquired Streptococcus pneumoniae meningitis illnesses in Huntington, West Virginia, from 1978 to 1997. Fourteen (36.8%) of 38 adults and 2 (11.8%) of 17 children died. Serotypes 6, 23, 3, and 18 accounted for 20 (41.7%) of 48 strains available for serotyping. Of 40 strains available for antimicrobial susceptibility testing, 1 serotype 19 and 1 serotype 23 strain showed intermediate resistance and a second serotype 23 strain showed high resistance to penicillin; all three patients survived. The case-fatality rates among adults who received penicillin alone, gentamicin in combination, or vancomycin and cephalosporin together were 57.1%, 55.5%, and 60%, respectively, and among those who received chloramphenicol or a third-generation cephalosporin, they were 11.1% or nil, respectively. No child died who received chloramphenicol or vancomycin. Two (33%) of 6 children died who received a third-generation cephalosporin; both were critically ill when initially treated. No child and one adult had received pneumococcal vaccine prior to becoming ill.

Bacteremic pneumococcal pneumonia in one American City: a 20-year longitudinal study, 1978-1997.

A surveillance of bacteremic pneumococcal pneumonia was conducted in Huntington, West Virginia, from 1978 to 1997 to investigate case-fatality rates, incidence of disease, capsular types, and antibiotic usage. Our study population comprised consecutive inpatients admitted to the hospitals in Huntington, West Virginia, and included 45 children younger than 15 years and 328 adults. All blood isolates were serotyped by capsular swelling procedures; clinical characteristics, treatment, and outcome for all patients were abstracted from hospital charts. The overall case-fatality rate was 20.3%, with most deaths occurring among adults older than 50 years. Case-fatality rates peaked at 37.7% among patients 80 years of age and older. Only 1 of 45 (2.2%) children died. Case-fatality rates declined in each successive 5-year period, from 30.2% in 1978-1982 to 15.6% in 1993-1997. In that same period, incidence rates increased severalfold among children younger than 4 years to 44.5 cases per 100,000 population and among adults 70 years and 80 years of age and older to 38.5 and 76.2 cases per 100,000, respectively. Of the 34 serotypes isolated, 10 accounted for two thirds of the cases of pneumonia: 1, 4, 9, 14, 3, 6, 12, 5, 23, and 19 (in rank order). Chronic renal disease and arteriosclerotic heart disease increased the risk of death. Treatment regimens that included a macrolide and a penicillin or cephalosporin resulted in the lowest case-fatality rate in adults older than 50 years: 6% in 1993-1997. In conclusion, as bacteremic pneumococcal pneumonia evolved over time, the case-fatality rate decreased, its incidence increased, predominant capsular types changed, and treatment regimens that included a macrolide resulted in the lowest fatality rates.

Identification of a variant subgroup A strain of respiratory syncytial virus.

During epidemiologic surveillance of children with respiratory syncytial virus (RSV) disease in Huntington, W.Va., we identified seven strains of a new variant subgroup A RSV (subgroup A-Var) by their reactions in an enzyme immunoassay with two anti-F monoclonal antibodies (MAbs) specific for two epitopes, F1 and F4, generated against the subgroup B RSV. The prototype strain of subgroup A and all other subgroup A field strains from that epidemiologic year failed to react with these two subgroup B MAbs. Additional enzyme immunoassays with 18 subgroup B anti-F MAbs specific for 14 epitopes showed that subgroup A-Var strains also reacted with a MAb specific for the subgroup B F2 epitope. In a radioimmune precipitation assay, the molecular size of the subgroup A-Var F2 subunit of the fusion (F) protein clearly differed from those of both prototype strains of subgroup A and subgroup B RSV. The molecular size of the F2 subunit of subgroup A-Var (24 kDa) was intermediate between the size of the F2 subunit of subgroup A (25 kDa) and that of subgroup B (23 kDa). However, the molecular sizes of the F1 subunits of both subgroup A and subgroup A-Var were identical (54 kDa) and slightly larger than those of the F1 subunits of both subgroups B1 and B2 (53 kDa). These data suggest that subgroup A-Var may represent a distinct RSV A subgroup, analogous to subgroup B1 and B2 RSV, and it is the first-identified naturally occurring subgroup A RSV with an F protein different from that of the prototype A RSV.

Emergence of penicillin-resistant invasive pneumococci in a single American community.

Three decades ago, penicillin-resistant strains of Streptococcus pneumoniae were first reported. Since then, myriad penicillin resistant strains of S. pneumoniae have been identified worldwide and in the United States. No resistant or intermediate resistant strains have been reported in West Virginia because testing has not been done. Between 1983 and 1994, the authors' surveillance of invasive pneumococcal disease in metropolitan Huntington, West Virginia, identified 356 pneumococcal strains from blood and other usually sterile sites, including 110 strains belonging to serotypes 6, 9, 14, 19, and 23, the main serotypes exhibiting penicillin resistance. The authors tested these serotypes for penicillin susceptibility by the E-test. Sixteen (14.5%) strains of types 6, 9, 14, 19, and 23 exhibited intermediate resistance to penicillin. No highly resistant strains were identified. Most of the intermediate resistant strains of types 9, 14, and 23 were detected in epidemiologic years 1992-1994. The increasing number of intermediate resistant penicillin strains signals the need for routine testing of invasive pneumococcal strains for penicillin susceptibility and necessitates appropriate antibiotic usage.

Identification of subgroups of bovine respiratory syncytial virus.

The occurrence of antigenic variation among nine isolates of bovine respiratory syncytial virus (BRSV) was determined by examining their reaction patterns to human respiratory syncytial virus (HRSV) subgroup A and B monoclonal antibodies (MAbs) by enzyme immunoassay and radioimmunoprecipitation with fractionation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis by using MAbs and polyclonal antisera to HRSV and BRSV. Shared epitopes were demonstrated on four of five structural proteins between BRSV and both subgroups A and B of HRSV. The nine isolates of BRSV showed different patterns of reactivity in enzyme immunoassays with panels of MAbs to HRSV subgroups A and B. Major variations in the molecular weights of the P (phosphoprotein) and F (fusion protein) proteins were demonstrated among the BRSV isolates tested. These results suggest that BRSV belongs to a different antigenic grouping than HRSV and that BRSV is composed of two distinct subgroups.

Distinguishing between respiratory syncytial virus subgroups by protein profile analysis.

We subgrouped 75 strains of respiratory syncytial virus by a protein profile method (PPM) which relies on different mobilities of the phosphoprotein in one-dimensional polyacrylamide gel electrophoresis and does not require monoclonal antibodies. When compared with enzyme immunoassay, PPM correctly subgrouped 54 of 56 subgroup A and all 19 subgroup B strains.