@2024 Afarand., IRAN

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ISSN: 2251-8215    Sarem Journal of Reproductive Medicine 2019;3(2):53-57

Background
... [1-3]. Group B streptococci are found in 5% to 30% of the pregnant women that can be considered as infectious sources at the time of infant birth [4]. Group B streptococci are the most important cause of death in the first week of birth, and infection can occur prematurely in the first week of life or later in the age of more than 1 week (in the first trimester of life) [5].
Previous Studies
... [6-15]. Resistance to these drugs has been reported in the United States from 2006 to 2008 by 25% to 32% for erythromycin and 13% to 20% for clindamycin [16]. Although erythromycin is the second-line treatment of GBS, its use has recently been prohibited by the Centers for Disease Control and Prevention (CDC), but clindamycin is still recommended as an effective drug for GBS [11]. In 2008, in some European countries, resistance to erythromycin was reported to be between 6% to 15% [4]. In 2013, Farhadifar et al. reported resistance to GBS as about 7% [14].
Aim(s)
The aim of this study was to investigate the isolated strains of group B streptococci and pattern of phenotypic induced resistance to clindamycin in pregnant women.
Research type
This study is descriptive-cross sectional.
Research society, place and time
on a vaginal culture sample of pregnant women, who were referred to Sarem Hospital for delivery from September 23, 2014 to May 2015.
Sampling method and number
Sampling from 861 pregnant women was done by census method. Pregnant women aged 18 to 45 years, who were referred to normal pregnancy care (from 24 to 37 gestational age), were enrolled in the study. People who had a history of the disease and antibiotic use, as well as any manipulations (Cervical cerclage), were not included in the study. Culture and staining of microbial lams: After clinical examinations, two swabs were taken from the vaginal discharge of the samples and sent to a microbiological laboratory in sterile tubes containing 1ml of physiological serum. For gram staining, two expansions of the discharge were prepared on a lam. Samples were passaged in less than 1 hour after sampling, using standard loop, on the blood agar culture medium (5% sheep blood (Farayande Beh-tashkhis; Iran), Eosin Methylene blue agar (Kandaidea; Iran), chocolate agar (Farayande Beh-tashkhis; Iran), Thioglycolate broth (Farayande Beh-tashkhis; Iran), and Sabouraud dextrose agar (Farayande Beh-tashkhis; Iran). Eosin Methylene blue, blood agar, and Thioglycolate plates were incubated at 1±35°C and chocolate agar plate was incubated in an anaerobic jar (5% carbon dioxide) at the same temperature. The lams were stained by gram staining. Discrimination test: To investigate the growth of GBS bacteria, samples were examined after 18-24 hours in terms of the presence of small hemolytic beta colonies. After isolation, the presence of GBS was approved by catalase, gram staining, and Camp tests. The microbial susceptibility testing was performed according to the Clinical and Laboratory Standards Institute (CLSI) guidelines by the disk diffusion method in agar (Kirby-Bauer method) [17]. The used discs (ROSCO; United States) included penicillin, cefalexin, ceftriaxone, ceftazidime, ampicillin, ciprofloxacin, clindamycin, and erythromycin. In order to investigate the phenotypic induced resistance to clindamycin by erythromycin (D test), they were placed close to the distance of about 20 mm. This test was performed for positive samples [4]. Statistical analysis was performed, using SPSS 20 software.
Used devices&materials

Findings by Text
Of the 861 samples sent to the laboratory, 296 cases (34.38%) of the pathogens were isolated by culture (Diagram 1) and 141 of them (16.38%) were positive for GBS bacteria.The sensitivity of GBS isolates to penicillin, cefalexin, and ceftazidime was 98.58%, 97.87%, and 98.58%, respectively. Penicillin halo diameter was less than 22 mm in 2 isolates, while no resistance was observed for ampicillin and ceftriaxone in the isolates. Four of the isolates (2.84%) were resistant to ciprofloxacin (Table 1). Out of 141 positive GBS samples, 21 (14.89%) of the samples showed induction of clindamycin resistance, and 9 (6.38%) had concurrent resistance to erythromycin and clindamycin.
Main comparison to the similar studies
Aali et al. reported the prevalence of GBS in pregnant women as 9.2% at Afzalipour Hospital, Kerman [8]. In 2008, Fatemi et al. examined 330 vaginal swabs for pregnant mothers in Hedayat Hospital, Tehran, 86 of which were positive (20.8%) [18]. Of the 1,197 patients referred to Zeinabiyeh Hospital, Shiraz, Namvar Jahmari et al. reported 110 cases (9.1%) of positive GBS cultures, as well as 66 infants infected with GBS. In 2011, Hamedi et al. reported GBS colonization in 200 pregnant women as 6% at Ghaem Hospital, Mashhad [6]. In these studies, according to the climatic and demographic conditions, the colonization rate of GBS is 10% to 20%, and the present study is consistent with these studies. Many studies conducted in European countries such as Switzerland, Denmark, and the United Kingdom have reported GBS colonization rates between 5% and 15% [10, 12, 15]. Several studies have reported the increased resistance of this bacterium to macrolides and lincosamides in the world [2, 10, 20]. Resistance to erythromycin is around 54% [12] in the world and 39% for clindamycin [20]. In Examining the resistance of GBS strains, Kappana et al. observed the induction of clindamycin resistance by erythromycin in 8.6% of samples using D-test, in addition to reporting drug resistance to clindamycin and erythromycin (28% and 30%, respectively) [17].In the present study, in 14.89% of GBS positive samples, D test was positive and 6.38% showed concurrent resistance to erythromycin and clindamycin. Due to the reported prevalence of this bacterium in the present study and induction of clindamycin resistance by erythromycin, for the appropriate treatment, a diagnostic test of D test is required.
Suggestions
it is suggested that more specific studies be carried out on the resistant genes of this bacterium, and the possibility of using Phage therapy for resistant strains of this bacterium should also be investigated.
Limitations
The limitations of this study include limiting the sampling of pregnant women who, due to special circumstances during the last weeks of pregnancy, did not have the ability to cooperate correctly with regard to proper sampling, Considering the fact that microbial resistance has become widespread today.
Conclusions
Among isolated bacteria, 16.38% of them are part of group B streptococci, of which 14.98% have induction of clindamycin resistance and in 6.38% of them, they have concurrent resistance to erythromycin and clindamycin.
Acknowledgments
It is time to thank the dear colleagues of the Perinatology Clinic of Sarem Paramedical Hospital for their sincere and relentless cooperation.
Conflict of interest
None declared any conflicts of interests.
Ethical Permissions
This study does not have any ethical prohibitions.
Funding Sources
The project has been funded by the Sarem Fertility and Infertility Research Center.

TABLES and CHARTS

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