Penicillin susceptibility and macrolide-lincosamide-streptogramin B resistance in group B Streptococcus isolates from a Canadian hospital

Serotype distribution, antimicrobial resistance, and molecular characterization of group B Streptococcus isolates from Chinese pregnant woman

OBJECTIVE

This study was aimed to investigate the serotypes, antibiotic susceptibilities, and multi-locus sequence type (MLST) profiles of group B Streptococcus (GBS) in the Beijing area.

METHODS

Lower vaginal and rectal swabs were obtained from pregnant women of 35-37 gestational weeks (GWs) who attended the Beijing Obstetrics and Gynecology Hospital. All GBS isolates were identified with Gram staining, catalase reaction assays, and CAMP tests, followed by antibiotic susceptibility testing, serotype identification, multilocus sequence typing and erythromycin resistance gene analysis (ermB and mefE).

RESULTS

From July 2020 to June 2022, 311 (5.17%) of 6012 pregnant women that were screened for GBS colonization were detected positive. Of the eight serotypes identified (III, Ia, Ib, IV, II, VIII, V, and NT), serotypes III (43.09%), Ia (34.08%) and Ib (17.04%) were the predominant species. In the antimicrobial susceptibility experiments, the resistant rates measured for erythromycin, clindamycin, levofloxacin, and tetracycline were 76.21%, 63.99%, 50.80%, and 81.03%, respectively, and 7.6% of GBS isolates showed inducible clindamycin in resistance (D-test phenotype). Meanwhile, the multilocus sequence typing analysis showed that sequence type 19 (ST19) (30.34%) and ST10 (18.62%) were the dominant sequence types. Among the 237 erythromycin-resistant isolates, 176 harbored ermB (128, 54.00%) or mefE (48, 20.30%) gene alone.

CONCLUSION

The infection rates, serotypes or MSLT distribution, and antimicrobial resistance of GBS in Beijing area were investigated, which may be applied in analyses of the epidemiological characteristics of GBS. This contributes to the basic knowledge required for successful GBS vaccine development suited for disease prevention and treatment in China, as well as the implementation of effective clinical antimicrobials.

Recent development and fighting strategies for lincosamide antibiotic resistance

SUMMARYLincosamides constitute an important class of antibiotics used against a wide range of pathogens, including methicillin-resistant Staphylococcus aureus. However, due to the misuse of lincosamide and co-selection pressure, the resistance to lincosamide has become a serious concern. It is urgently needed to carefully understand the phenomenon and mechanism of lincosamide resistance to effectively prevent and control lincosamide resistance. To date, six mobile lincosamide resistance classes, including lnu, cfr, erm, vga, lsa, and sal, have been identified. These lincosamide resistance genes are frequently found on mobile genetic elements (MGEs), such as plasmids, transposons, integrative and conjugative elements, genomic islands, and prophages. Additionally, MGEs harbor the genes that confer resistance not only to antimicrobial agents of other classes but also to metals and biocides. The ultimate purpose of discovering and summarizing bacterial resistance is to prevent, control, and combat resistance effectively. This review highlights four promising strategies, including chemical modification of antibiotics, the development of antimicrobial peptides, the initiation of bacterial self-destruct program, and antimicrobial stewardship, to fight against resistance and safeguard global health.

Drugs for the Prevention and Treatment of Sepsis in the Newborn

Antimicrobial medications are the most commonly used medications in the neonatal intensive care unit. Antibiotics are used for infection prophylaxis, empiric treatment, and definitive treatment of confirmed infection. The choice of medication should be informed by the epidemiology and microbiology of infection in specific clinical scenarios and by the clinical condition of the infant. Understanding evolving pathogen susceptibility to antimicrobials and key pharmacotherapy determinants in neonates can inform optimal antibiotic use.

Invasive group B streptococcal infection in infants in Shenzhen, China

OBJECTIVE

In this study, we aim to investigate the distribution and antibiotic susceptibility of Group B Streptococcus (GBS) in infants younger than 90 days in Shenzhen, China.

METHODS

A retrospective study was conducted to evaluate GBS infection over an 4-year period. Starting from January 2010, we evaluated the laboratory data, clinical manifestations, treatment and outcomes of patients admitted to our hospital with invasive GBS infection. Furthermore, we analyzed distribution of isolates from infants < 90 days with GBS or non-GBS invasive infection.

RESULTS

The registered cases of invasive GBS infection (n = 40, male: 23, female: 17) were classified as sepsis (n = 24), meningitis (n = 2), or both (n = 14). Patients with sepsis recovered completely. Among patients with meningitis, 1 (6.3%) died from ventricular hemorrhage, and 4 (25%) showed sequelae during the follow up of 3 months. Among the 377 isolates (45 from the 40 infants with invasive GBS infection, 332 from infants with non-GBS invasive infections), the detection rate of GBS was 11.9% (45/377), accounted for 11.2% of sepsis and 18.4% of meningitis cases. All 45 isolates were susceptible to penicillin, vancomycin, linezolid, tigecycline, and quinolones. Resistance to erythromycin, clindamycin, and tetracycline was found in 19 (42%), 29 (64%), and 42 (93%) isolates, respectively.

CONCLUSION

GBS is an important pathogen in infants < 90 days in Shenzhen, China, which results in high mortality and neurological sequelae. GBS strains show strong resistance to clindamycin and erythromycin.

[Practical management of neonatal sepsis risk in term or near-term infants]

Incidence of neonatal early-onset sepsis has dramatically declined in France from 0.65 to 0.23‰ live births in 10 years since national guidelines to detect and treat intrapartum women with group B streptococcus colonization have been adopted. However, neonatal early-onset sepsis continues to be a common healthcare burden. Group B streptococcus (GBS) remains the leading cause of bacterial infection in term or near-term infants. As a result of prevention strategies, approximately 30% of pregnant women and more than 2% of newborns are treated with systemic antibiotics. Concerns have been expressed about the safety of wide use of antibiotics such as antibiotic resistance, emergence of Escherichia coli infections, and long-term side effects due to gut microbiota modifications. New recommendations from the Centers of Disease Control in the United States and from European countries aim at improving GBS detection methods, updating algorithms for GBS intrapartum chemoprophylaxis in pregnant women, defining high-risk newborns more efficiently, and limiting biological evaluation in low-risk newborns.

Cloning, expression, purification, crystallization and preliminary X-ray diffraction analysis of glyceraldehyde-3-phosphate dehydrogenase from Streptococcus agalactiae NEM316

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is an essential enzyme involved in glycolysis. Despite lacking the secretory signal sequence, this cytosolic enzyme has been found localized at the surface of several bacteria and fungi. As a surface protein, GAPDH exhibits various adhesive functions, thereby facilitating colonization and invasion of host tissues. Streptococcus agalactiae, also known as group B streptococcus (GBS), binds onto the host using its surface adhesins and causes sepsis and pneumonia in neonates. GAPDH is one of the surface adhesins of GBS binding to human plasminogen and is a virulent factor associated with host colonization. Although the surface-associated GAPDH has been shown to bind to a variety of host extracellular matrix (ECM) molecules in various bacteria, the molecular mechanism underlying their interaction is not fully understood. To investigate this, structural studies on GAPDH of S. agalactiae were initiated. The gapC gene of S. agalactiae NEM316 encoding GAPDH protein was cloned into pET-28a vector, overexpressed in Escherichia coli BL21(DE3) cells and purified to homogeneity. The purified protein was crystallized using the hanging-drop vapour-diffusion method. The GAPDH crystals obtained in two different crystallization conditions diffracted to 2.8 and 2.6 Å resolution, belonging to two different space groups P2₁ and P2₁2₁2₁, respectively. The structure was solved by molecular replacement and structure refinement is now in progress.