Rapid identification of material colonization with group B streptococci by use of fluorescent antibody

Abstract

To identify women colonized with group B streptococci during parturition, we used pooled type-specific fluorescent antibody to examine vaginal swabs enriched by preincubation in selective broth medium. In preliminary experiments, group B streptococcus strain III-Bell was reliably detectable with fluorescent antibody at concentrations of greater than 10(5) colony-forming units per ml, achieved after 6 h of incubation of small inocula (18 to 26 colony-forming units). Of the vaginal swabs from 924 parturient women examined prospectively by both fluorescent antibody and selective bacteriology techniques, group B streptococci were isolated in 154. The sensitivity of the fluorescent antibody technique increased with increasing incubation time and ranged from 49% (3 to 6 h) to 81% (7 to 12 h) to 83% (13 to 18 h) to 93% (greater than 18 h). Colonized mothers identified within 6 h by the fluorescent antibody technique had higher rates of vertical transmission to their newborn infants (61%) than colonized mothers whose fluorescent antibody examinations were negative within this time interval (32%; P = 0.027). However, because of the timing of their admissions, none of the colonized mothers of the four infants who developed early-onset group B streptococcal sepsis were identified with fluorescent antibody until after delivery. Although its sensitivity approaches selective culture methods after 6 h of incubation, fluorescent antibody examination of vaginal swabs does not appear to offer a practical approach to identifying colonized parturient women for intrapartum antibiotic prophylaxis of group B streptococcal infection.

Prevalence of early-onset neonatal infection among newborns of mothers with bacterial infection or colonization: a systematic review and meta-analysis

“…A sensitivity analysis excluding studies with known or possible antibiotic use showed a slight increase in prevalence of neonatal infections in studies that tested lab outcomes (1.1%, 95% CI 0.2-2.0), studies that diagnosed clinical signs of neonatal infection (6.5%, 95% CI -6.5-19.5), and studies that collected clinical signs of infection and conducted labs tests (7.6%, 95% CI 1.4-13.8).

Figure 3 Maternal colonization and neonatal infection [ 54 - 86 ] .

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Late-onset Neonatal Infections 1997 to 2017 Within a Cohort in Western Sweden—The Last 21 Years of a 43-Year Surveillance

“…If the mother is colonized with GBS, the bacteria can pass from the vagina into the amniotic fluid and cause IUFD and preterm birth (130,131). A further risk for exposure happens during passage through the birth canal (132) and after birth via breast milk or the environment (133,134).…”

Early detection of streptococci in swabs by latex agglutination before culture

“…When traditional techniques for the detection of streptococci are used, at least 18 h elapse between the receipt of a specimen and the issuance of a culture report; however, there are some circumstances such as major burns for which the early detection of Streptococcus pyogenes may be important. Various methods for the earlier detection of S. pyogenes and other streptococci have been described, including short incubation of swabs in selective enrichment broths followed by fluorescent-antibody staining (1,9), staphylococcal coagglutination (10,11), latex agglutination (7,9), or counterimmunoelectrophoresis (4) to detect streptococcal antigens in the broth. Methods involving the direct examination of the specimen include the use of fluorescentantibody staining smears (6, 8), the extraction of throat scrapings with nitrous acid and precipitation detection of antigen (5), and the detection of streptococcal antigen in throat gargles with latex agglutination (3).…”

“…The Streptex method has been shown to be reliable for TABLE_ 1 a Values in parentheses are the percentages of total positive isolations. The average percentages were: 81% (isolation and latex agglutination), 19% (isolation), and 6% (latex agglutination).…”