Clinical Evaluation of the Walk-Away Specimen Processor and ESwab for Recovery of Streptococcus agalactiae Isolates in Prenatal Screening Specimens

Abstract

Rectal/vaginal specimens (n ‫؍‬ 97) were collected in parallel using ESwab and Liquid Stuart (LS) rayon fiber wrapped swab collection devices. Each collection device was used to directly inoculate culture medium and LIM broth. Medium inoculation by ESwab was conducted using the Walk-Away specimen processor (WASP). Medium inoculation by the LS device was conducted manually. The sensitivities of ESwab and LS upon direct plating were 93.8% and 87.5%, respectively, and increased to 96.9% and 90.6%, respectively, following broth enrichment.T ransient colonization of the female urogenital tract by Streptococcus agalactiae, or group B Streptococcus (GBS), is a recognized risk factor for the development of neonatal infections acquired during the birthing process. These infections are characterized by onset of sepsis, pneumonia, and meningitis within the first 7 days of life and carry a mortality rate of up to 7% (1, 2). While GBS has been associated with bacteremia, soft tissue infections, pneumonia, and meningitis in adults (3), carriage is typically asymptomatic, with a point prevalence of 10 to 30% in pregnant women (2, 4-6). The identification of GBS during routine prenatal screening aids in decreasing the incidence of invasive GBS disease in newborns through the administration of intrapartum antibiotic prophylaxis in women with a positive GBS test result (7). Further, the screening of pregnant women at 35 to 36 weeks gestation has been recommended by Centers for Disease Control and Prevention (2). Therefore, sensitive methods for detecting GBS in routine prenatal screening specimens are a key component in preventing neonatal disease (2).The use of enrichment broth, selective and chromogenic medium, and molecular diagnostics (6,(8)(9)(10)(11)(12)(13) has increased the sensitivity of GBS detection; however, the initial collection and processing of specimens have largely remained unchanged. Advancements in technology and automation in the clinical microbiology lab have made available more efficient methods for specimen collection and processing, which have the potential to improve the sensitivity of screening and recovery of GBS and other pathogens (14-18). The introduction of ESwab (Copan Diagnostics, Murrieta, CA), when used in combination with the Walk-Away specimen processor (WASP) (Copan Diagnostics), has the potential to improve the efficiency and reproducibility of specimen collection, processing, and pathogen recovery through increased sensitivity, specificity, and reduced turnaround time (14-19). Traditional fiber wrapped swabs coupled with nonnutritive transport medium, such as Liquid Stuart or Amies Gel, aid in the preservation of microorganisms during transit to the clinical laboratory; however, the inefficient transfer or release of microorganisms from a traditional fiber swab may reduce the overall sensitivity of the diagnostic procedure. In contrast, flocked swabs are constructed with a solid bulbous head that is covered in fibers protruding perpendicularly to the swab shaft. The combination of a liquid...

Prevalence, antimicrobial susceptibility patterns, serotypes and risk factors for group B streptococcus rectovaginal isolates among pregnant women at Kenyatta National Hospital, Kenya; a cross-sectional study

“…Streptococcus agalactiae also called Group B Streptococcus (GBS), causes invasive infections mainly in pregnant women and neonates [1]. Temporary GBS colonization of the female urogenital tract is a known causative factor of neonatal infections acquired during the childbirth process [2]. Acquisition of GBS can be perinatal during labour or inutero through transmission of the bacteria from the maternal vaginal or anorectally colonized mucosa.…”

“…GBS is also a risk factor for neonatal sepsis and mortality that is associated with preterm birth [3]. Neonatal GBS infection can be early or late onset with earlyonset disease (EOD) ensuing within the first 7 days of life and presents as pneumonia, meningitis, and sepsis that carries a mortality rate of up to 20% [2].…”

The relevance of sink proximity to toilets on the detection of Klebsiella pneumoniae carbapenemase inside sink drains

“…Both swab types used for specimen collection demonstrated similar yield when used for direct PCR; however, KPC-producing isolates were only recovered from specimens collected with ESwab, suggesting that this might be a better tool for collection, which is consistent with previous reports. [6][7][8] To date, no studies have examined the relevance of sink proximity to toilets in patient rooms. Based on recent data by Mathers and colleagues, 3 it could be plausible that contamination of sinks next to toilets is occurring through biofilms growing in communal pipes between toilets and sinks.…”

Detection of Group B Streptococcus Directly from Collected ESwab Samples by Use of the BD Max GBS Assay

“…Advancements in technology in clinical microbiology and molecular laboratories have made available more efficient methods of specimen collection and processing, which along with the detection methods have the potential to improve the sensitivity of screening and the recovery of GBS and other pathogens. The combination of a liquid-based transport medium and flocked swab, such as the ESwab (Copan Diagnostics, Murrieta, CA) collection device, has been demonstrated to increase the recovery of bacteria from clinical sites compared to that of standard fiber-wrapped swabs ( 14 – 17 ). The use of ESwab samples with the BD Max GBS assay may potentially improve and speed up the detection of GBS in pregnant women by eliminating the Lim broth inoculation and incubation steps.…”