Streptococcus agalactiae clinical isolates in Northwest Iran: antibiotic susceptibility, molecular typing, and biofilm formation
GMS HYGIENE AND INFECTION CONTROL
Authors: Shadbad, Mohammad Alipour; Kafil, Hossein Samadi; Rezaee, Mohammad Ahangarzadeh L.; Farzami, Marjan Rahnamaye; Dehkharghani, Alireza Dolatyar; Sadeghi, Javid; Gholizadeh, Pourya; Khodaei, Farzaneh; Aghazadeh, Mohammad
Abstract
Background: Group B Streptococcus (S. agalactiae) is one of the colonizing bacteria in pregnant women which can be a causative agent of meningitis and neonatal sepsis. This organism has also been increasingly related to invasive infections in non-pregnant adults. Objective: In present study, we aimed to characterize the clonality of biofilm-producing S. agalactiae isolates from various sources from two different clinical laboratories in Tehran, Iran. Materials and Methods: S. agalactiae isolates were collected from community-acquired (CA) and hospital-acquired (HA) infections in pregnant and non-pregnant adults. The antimicrobial susceptibility patterns and biofilm formation ability were determined. In addition, pulse field gel electrophoresis (PFGE) was used to verify the clonal diversity of isolates. Results: Out of the 87 isolates, 15 (16.6%) formed biofilm. The antibiotic resistance rate was 98.85% for clindamycin, 98.85% for tetracycline, followed by 29.88% for erythromycin, 9.19% for moxifloxacin and 6.89% for levofloxacin. The PFGE patterns revealed a total of 16 different clusters consisting of 6 single types (STs). Conclusion: This study evaluated the biofilm formation of clinical S. agalactiae, which may be a step towards understanding its role in pathological processes. Biofilm formation was significant only in the hypervirulent ST-17 clone. Intraclonal spread of isolates indicates that a local lineage of isolates is responsible for infection by these bacteria.
Group B streptococci cultured in urine during pregnancy associated with preterm delivery: a selection problem?
JOURNAL OF MATERNAL-FETAL & NEONATAL MEDICINE
Authors: Khalil, Mohammed R.; Uldbjerg, Niels; Moller, Jens K.; Thorsen, Poul B.
Abstract
Objective: To investigate an association between Group B streptococci (GBS) in urine culture during pregnancy and preterm delivery. Methods: A population-based cohort consisted of all the pregnant women (n = 36,097) from the catchment area of Lillebaelt Hospital, Denmark, during the period January 2002 -December 2012. The cohort of 34,285 singleton pregnancies used in this study was divided into three groups. Group I (N = 249) included women whose urine culture was positive for GBS; group II (N = 5765) included women whose urine culture was negative for GBS; and group III (N = 28 271) included women whose urine had not been cultured during pregnancy. Primary outcome was preterm delivery before 37 weeks' gestation (PTD). Results: We did not find an association between PTD and GBS bacteriuria in the cultured groups (odds ratios (OR) = 0.89; 95% CI: 0.5-1.4) (Table 1). After controlling for potential confounders, the PTD remained not associated with GBS bacteriuria (adjusted OR = 0.99; 95% CI: 0.6-1.6). Combined, the cultured groups (I and II) were associated with a statistically significant higher risk for PTD, when compared with the group with no urine specimens taken for culture (OR = 1.96; 95% CI: 1.8-2.2 and adjusted or 1.80; 95% CI 1.6-2.0). The cultured group of women differed considerably from the group of women with no urine specimens taken for culture on the vast majority of variables examined. Conclusions: No association between asymptomatic GBS bacteriuria and preterm delivery among women with singleton pregnancy and urine specimens cultured during pregnancy was found. Previous suggestions of such association may have been compromised by a selection problem for testing due to a high-risk profile of pregnancy complications in pregnant women selected for urine culture.