Prevalence, population structure, distribution of serotypes, pilus islands and resistance genes among erythromycin-resistant colonizing and invasive Streptococcus agalactiae isolates recovered from pregnant and non-pregnant women in Isfahan, Iran

Abstract

Background The information on antibiotic resistance and molecular features of Group B Streptococcus (GBS) are essential for epidemiological purposes as well as vaccine development. Therefore, we aimed to assess the antimicrobial resistance profiles and molecular characteristics of GBS isolates in Isfahan, Iran. A total number of 72 colonizing and invasive GBS were collected from pregnant and non-pregnant women. The GBS isolates were analyzed for resistance profiles, capsular genotyping, and detection of PI-1, PI-2a, PI-2b, hvgA, ermB, ermTR, lnuB and, mefA genes. Besides, erythromycin-resistant strains were subjected to multilocus sequence typing (MLST). Results The prevalence of colonizing and invasive GBS were 11 and 0.05%, respectively. The frequency of capsular serotypes was as follows: III (26.3%), Ia (20.83%), Ib and V (each 15.2%), IV (9.7%), II (8.3%), VII (2.7%), and VI (1.3%). Overall frequencies of PIs were as follows: PI-1, 37.5%, PI-1 + PI-2a, 30.5%, PI-1 + PI-2b, 29.1% and PI-2b, 2.7%. Two maternal colonizing GBS (2.6%) were hvgA positive and were belonged to ST-17/CPS-III/PI-1 + PI-2b lineage. Among 30(41.6%) erythromycin resistant GBS, 21 isolates (70%) harbored ermB gene, followed by ermTR (23.3%) and mefA (10%). One clindamycin-resistant isolate harbored the lnuB gene. MLST analysis revealed the following five clonal complexes (CCs) and nine STs: (CC-19/ST-335, ST-19, and ST-197), (CC-12/ST-43, ST-12), (CC-23/ST-163, ST-23), (CC-17/ST-17) and (CC-4/ST-16). Conclusion The study shows an alarmingly high prevalence of erythromycin-resistant GBS in Iran. In addition, we report dissemination of ST-335/CPS-III clone associated with tetracycline and erythromycin resistance in our region. The distribution of capsular and pilus genotypes varies between invasive and colonizing GBS that could be helpful for vaccine development.

Distribution Of Virulence Factors Genes And Their Association With Antibiotics Resistance In Streptococcus Agalactiae Isolated From Pregnant Women In Al Anbar City

“…The percentage of ermB in our study was very high compared to another study in Iran, where the gene was present at a low rate (29.3%) (Ghamari et al, 2022). Another study in Iran was (70%) (Motallebirad et al, 2021). ermB is one of erm genes that encoded Ribosomal modification, which is associated with (cMLSB)co-resistance to MLSB antibiotics with high-level resistance to all MLSB antibiotics (Ghamari et al, 2022).…”

Emerging Fatal Ib/CC12 Hypervirulent Multiresistant Streptococcus agalactiae in Young Infants With Bloodstream Infection in China

“…The founders of CC12 and CC10, namely ST12 and ST10 respectively, were SLVs. Genetically, CC12 was derived from CC10 and flourished as a sub-clone in evolution ( Motallebirad et al, 2021 ). The genomes of CC12 and CC10 strains had more than 1700 orthologous clusters, but the genomes of CC12 were more unstable and variable because they had more mobile genetic elements.…”

Maternal Group B Streptococcal Rectovaginal Colonization after Intrapartum Antibiotic Prophylaxis

“…Antibiotic resistance in GBS strains is a concern in the prevention of GBS invasive disease. The findings from recent studies support the increasing resistance to antibiotics used in GBS treatment [ 12 , 13 , 14 , 15 ], especially erythromycin and clindamycin, the second-line antibiotics recommended in cases of severe penicillin allergies, which have resistance rates of 21.3–74.1% in different regions [ 21 , 23 , 31 , 32 , 33 , 34 , 35 , 36 , 37 ]. The results of our study also demonstrated high resistance to erythromycin and clindamycin (40.0% and 21.4%, respectively).…”

“…For women allergic to penicillin with a history of severe reactions, the use of clindamycin or vancomycin is preferable [ 5 ]. However, recent studies have reported increasing antimicrobial resistance during GBS prevention [ 12 , 13 , 14 , 15 ]. Hayes et al reviewed antibiotic resistance in GBS prevention and reported that GBS is universally susceptible to beta-lactam antibiotics [ 14 ], whereas there have been reports of reduced susceptibility to beta-lactams, including penicillin, in some countries [ 16 , 17 ].…”