scholarly journals Prevalence and Mechanisms of Macrolide Resistance in Invasive and Noninvasive Group B Streptococcus Isolates from Ontario, Canada

2001 ◽  
Vol 45 (12) ◽  
pp. 3504-3508 ◽  
Author(s):  
Joyce C. S. de Azavedo ◽  
Mary McGavin ◽  
Carla Duncan ◽  
Donald E. Low ◽  
Allison McGeer
Keyword(s):  
Group B Streptococcus ◽  
Tetracycline Resistance ◽  
Macrolide Resistance ◽  
Limited Information ◽  
Erythromycin Resistance ◽  
Vaginal Swabs ◽  
Resistant Strains ◽  
Neonatal Blood ◽  
Methylase Gene ◽  
Group B

ABSTRACT Macrolide resistance has been demonstrated in group B streptococcus (GBS), but there is limited information regarding mechanisms of resistance and their prevalence. We determined these in GBS obtained from neonatal blood cultures and vaginal swabs from pregnant women. Of 178 isolates from cases of neonatal GBS sepsis collected from 1995 to 1998, 8 and 4.5% were resistant to erythromycin and clindamycin, respectively, and one isolate showed intermediate penicillin resistance (MIC, 0.25 μg/ml). Of 101 consecutive vaginal or rectal/vaginal isolates collected in 1999, 18 and 8% were resistant to erythromycin and clindamycin, respectively. Tetracycline resistance was high (>80%) among both groups of isolates. Of 32 erythromycin-resistant isolates, 28 possessed the ermmethylase gene (7 ermB and 21 ermTR/ermA) and 4 harbored the mefA gene; one isolate harbored both genes. One isolate which was susceptible to erythromycin but resistant to clindamycin (MIC, 4 μg/ml) was found to have thelinB gene, previously identified only inEnterococcus faecium. The mreA gene was found in all the erythromycin-resistant strains as well as in 10 erythromycin-susceptible strains. The rate of erythromycin resistance increased from 5% in 1995–96 to 13% in 1998–99, which coincided with an increase in macrolide usage during that time.

scholarly journals Genetic characterization and diversity of Streptococcus agalactiae isolates with macrolide resistance

2010 ◽  
Vol 59 (7) ◽  
pp. 780-786 ◽  
Author(s):  
Monika Brzychczy-Włoch ◽  
Tomasz Gosiewski ◽  
Małgorzata Bodaszewska ◽  
Wojciech Pabian ◽  
Małgorzata Bulanda ◽  
...  
Keyword(s):  
Streptococcus Agalactiae ◽  
Group B Streptococcus ◽  
Surface Protein ◽  
Macrolide Resistance ◽  
Surface Proteins ◽  
Erythromycin Resistance ◽  
High Genetic Diversity ◽  
Genes Encoding ◽  
Resistant Strains ◽  
Group B

Macrolide resistance in 169 Streptococcus agalactiae [group B streptococcus (GBS)] isolates originating from pregnant carriers was investigated. Using multiplex PCR the presence of genes encoding erythromycin resistance and capsular polysaccharides, as well as surface proteins, was determined. Random amplification of polymorphic DNA (RAPD) and PFGE were used to characterize specific clones among the isolates. In the examined population of women, erythromycin-resistant strains were found in 4.5 % of patients, whereas clindamycin-resistant strains were found in 3 % of patients, which was 16 % of strains resistant to erythromycin and 10 % of strains resistant to clindamycin among GBS isolates, respectively. Among the isolates, the largest percentage was represented by the constitutive macrolide–lincosamide–streptogramin B (cMLSB) phenotype (63 %), then the inductive macrolide–lincosamide–streptogramin B (iMLSB) phenotype (26 %) and the macrolide resistance (M) phenotype (11 %). The ermB gene was indicated in all isolates with the cMLSB phenotype and V serotype, whereas mefA/mefE genes were found in isolates with the M phenotype and Ia serotype. Among resistance isolates, serotype V was predominant (67 %), followed by serotypes II (15 %), Ia (11 %) and III (7 %). The most common surface protein encoding genes were alp3 (70 %), then rib (11 %), epsilon (7.5 %), bca (7.5 %) and alp2 (4 %). A statistically significant relationship between macrolide resistance, serotype V and the alp3 gene was demonstrated. PFGE, in comparison to the RAPD method, gave better genetic discrimination of GBS isolates. A relatively high genetic diversity among investigated strains was shown. In addition, the largest genetic homogeneity was found in serotype V.

scholarly journals Phenotypes and Genotypes of Erythromycin-ResistantStreptococcus pyogenes Strains in Italy and Heterogeneity of Inducibly Resistant Strains

1999 ◽  
Vol 43 (8) ◽  
pp. 1935-1940 ◽  
Author(s):  
Eleonora Giovanetti ◽  
Maria Pia Montanari ◽  
Marina Mingoia ◽  
Pietro Emanuele Varaldo
Keyword(s):  
Streptococcus Pyogenes ◽  
Tetracycline Resistance ◽  
Erythromycin Resistance ◽  
Testing Conditions ◽  
Resistant Strains ◽  
Methylase Gene ◽  
Set Up ◽  
Susceptibility Patterns ◽  
Disk Test ◽  
Level Resistance

ABSTRACT A total of 387 clinical strains of erythromycin-resistant (MIC, ≥1 μg/ml) Streptococcus pyogenes, all isolated in Italian laboratories from 1995 to 1998, were examined. By the erythromycin-clindamycin double-disk test, 203 (52.5%) strains were assigned to the recently described M phenotype, 120 (31.0%) were assigned to the inducible macrolide, lincosamide, and streptogramin B resistance (iMLS) phenotype, and 64 (16.5%) were assigned to the constitutive MLS resistance (cMLS) phenotype. The inducible character of the resistance of the iMLS strains was confirmed by comparing the clindamycin MICs determined under normal testing conditions and those determined after induction by pregrowth in 0.05 μg of erythromycin per ml. The MICs of erythromycin, clarithromycin, azithromycin, josamycin, spiramycin, and the ketolide HMR3004 were then determined and compared. Homogeneous susceptibility patterns were observed for the isolates of the cMLS phenotype (for all but one of the strains, HMR3004 MICs were 0.5 to 8 μg/ml and the MICs of the other drugs were >128 μg/ml) and those of the M phenotype (resistance only to the 14- and 15-membered macrolides was recorded, with MICs of 2 to 32 μg/ml). Conversely, heterogeneous susceptibility patterns were observed in the isolates of the iMLS phenotype, which were subdivided into three distinct subtypes designated iMLS-A, iMLS-B, and iMLS-C. The iMLS-A strains (n = 84) were highly resistant to the 14-, 15-, and 16-membered macrolides and demonstrated reduced susceptibility to low-level resistance to HMR3004. The iMLS-B strains (n = 12) were highly resistant to the 14- and 15-membered macrolides, susceptible to the 16-membered macrolides (but highly resistant to josamycin after induction), and susceptible to HMR3004 (but intermediate or resistant after induction). The iMLS-C strains (n = 24) had lower levels of resistance to the 14- and 15-membered macrolides (with erythromycin MICs increasing two to four times after induction), were susceptible to the 16-membered macrolides (but resistant to josamycin after induction), and remained susceptible to HMR3004, also after induction. The erythromycin resistance genes in 100 isolates of the different groups were investigated by PCR. All cMLS and iMLS-A isolates tested had theermAM (ermB) gene, whereas all iMLS-B and iMLS-C isolates had the ermTR gene (neither methylase gene was found in isolates of other groups). The M isolates had only the macrolide efflux (mefA) gene, which was also found in variable proportions of cMLS, iMLS-A, iMLS-B, and iMLS-C isolates. The three iMLS subtypes were easily differentiated by a triple-disk test set up by adding a josamycin disk to the erythromycin and clindamycin disks of the conventional double-disk test. Tetracycline resistance was not detected in any isolate of the iMLS-A subtype, whereas it was observed in over 90% of both iMLS-B and iMLS-C isolates.

Analysis of phenotype, genotype and serotype distribution in erythromycin-resistant group B streptococci isolated from vaginal flora in Southern Ireland

2009 ◽  
Vol 138 (2) ◽  
pp. 286-291 ◽  
Author(s):  
R. A. KIELY ◽  
B. LUCEY ◽  
L. COTTER
Keyword(s):  
Group B Streptococcus ◽  
Latex Agglutination ◽  
Macrolide Resistance ◽  
Pcr Analysis ◽  
Erythromycin Resistance ◽  
Childbearing Age ◽  
Group B Streptococci ◽  
Pcr Products ◽  
Resistant Group ◽  
Group B

SUMMARYThe screening of 2000 women of childbearing age in Cork between 2004 and 2006 produced 37 erythromycin-resistant group B streptococcus (GBS) isolates. PCR analysis was performed to determine the basis for erythromycin resistance. The ermTR gene was most frequently expressed (n=19), followed by the ermB gene (n=8). Four isolates harboured the mefA gene. Six isolates yielded no PCR products. Some phenotype–genotype correlation was observed. All isolates expressing the mefA gene displayed the M phenotype whilst all those expressing ermB displayed the constitutive macrolide resistance (cMLSB) phenotype. Of 19 isolates that expressed the ermTR gene, 16 displayed the inducible macrolide resistance (iMLSB) phenotype. Serotype analysis revealed that serotypes III and V predominated in these isolates. The identification of two erythromycin-resistant serotype VIII isolates among this collection represents the first reported finding of erythromycin resistance in this serotype. A single isolate was non-typable using two latex agglutination serotyping kits.

Associations between capsular serotype, multilocus sequence type, and macrolide resistance inStreptococcus agalactiaeisolates from Japanese infants with invasive infections

2013 ◽  
Vol 142 (4) ◽  
pp. 812-819 ◽  
Author(s):  
M. MOROZUMI ◽  
T. WAJIMA ◽  
Y. KUWATA ◽  
N. CHIBA ◽  
K. SUNAOSHI ◽  
...  
Keyword(s):  
Clonal Complex ◽  
Vaccine Development ◽  
Late Onset ◽  
Group B Streptococcus ◽  
Sequence Type ◽  
Macrolide Resistance ◽  
Invasive Infections ◽  
Resistant Strains ◽  
Group B ◽  
Sequence Types

SUMMARYStreptococcus agalactiae(group B streptococcus; GBS) isolates (n = 150) from infants with invasive infections between 2006 and 2011 were analysed for capsular serotype, multilocus sequence type, and antibiotic susceptibility. In cases with late-onset disease (n = 115), primary meningitis was predominant (62·6%), but represented only 39·1% in cases with early-onset disease (n = 23). The most common serotype was III (58·7%), followed by Ia (21·3%) and Ib (12·7%). Sequence types (STs) of serotype III strains included ST17 (50·0%), ST19 (26·1%), ST335 (18·2%), ST27 (4·5%), and ST1 (1·1%). Predominant STs of serotypes Ia and Ib were ST23 (81·3%) and ST10 (84·2%), respectively. No penicillin-resistant strains were detected, but 22·0% of strains hadmef(A/E),erm(A), orerm(B) genes, which mediate macrolide resistance. A new ST335, possessing anmef(A/E) gene belonging to clonal complex 19 gradually increased in frequency. Improved prevention of invasive GBS infections in infants requires timely identification, and ultimately vaccine development.

scholarly journals Performance of PhenoMatrix for the detection of Group B Streptococcus from recto-vaginal swabs

2021 ◽  
pp. 115427
Author(s):  
Claudio Foschi ◽  
Gabriele Turello ◽  
Tiziana Lazzarotto ◽  
Simone Ambretti
Keyword(s):  
Group B Streptococcus ◽  
Vaginal Swabs ◽  
Group B

scholarly journals Molecular Basis of Macrolide Resistance inCampylobacterStrains Isolated from Poultry in South Korea

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Bai Wei ◽  
Min Kang
Keyword(s):  
Molecular Mechanisms ◽  
Macrolide Resistance ◽  
23S Rrna ◽  
Rrna Gene ◽  
Campylobacter Coli ◽  
Erythromycin Resistance ◽  
23S Rrna Gene ◽  
Ribosomal Protein L22 ◽  
Resistant Strains ◽  
Azithromycin Resistance

We investigated the molecular mechanisms underlying macrolide resistance in 38 strains ofCampylobacterisolated from poultry. Twenty-seven strains were resistant to azithromycin and erythromycin, five showed intermediate azithromycin resistance and erythromycin susceptibility, and six showed azithromycin resistance and erythromycin susceptibility. FourCampylobacter jejuniand sixCampylobacter colistrains had azithromycin MICs which were 8–16 and 2–8-fold greater than those of erythromycin, respectively. The A2075G mutation in the 23S rRNA gene was detected in 11 resistant strains with MICs ranging from 64 to ≥ 512μg/mL. Mutations including V137A, V137S, and a six-amino acid insertion (114-VAKKAP-115) in ribosomal protein L22 were detected in theC. jejunistrains. Erythromycin ribosome methylase B-erm(B) was not detected in any strain. All strains except three showed increased susceptibility to erythromycin with twofold to 256-fold MIC change in the presence of phenylalanine arginine ß-naphthylamide (PAßN); the effects of PAßN on azithromycin MICs were limited in comparison to those on erythromycin MICs, and 13 strains showed no azithromycin MIC change in the presence of PAßN. Differences between azithromycin and erythromycin resistance and macrolide resistance phenotypes and genotypes were observed even in highly resistant strains. Further studies are required to better understand macrolide resistance inCampylobacter.

scholarly journals Genital tract group B streptococcal colonization in pregnant women: a South Indian perspective

2011 ◽  
Vol 5 (08) ◽  
pp. 592-595 ◽  
Author(s):  
Vijayan Sharmila ◽  
Noyal Mariya Joseph ◽  
Thirunavukkarasu Arun Babu ◽  
Latha Chaturvedula ◽  
Sujatha Sistla
Keyword(s):  
Pregnant Women ◽  
Group B Streptococcus ◽  
Colonization Rate ◽  
Antibiotic Susceptibility Pattern ◽  
South Indian ◽  
Vaginal Swabs ◽  
Rectal Swabs ◽  
Resistance To Penicillin ◽  
Group B ◽  
A Prospective Study

Introduction: During the last few decades, group B Streptococcus (GBS) has emerged as an important pathogen. The major reservoirs for GBS are the vagina and the peri-anal regions/rectum, and the colonization of these regions is a risk factor for subsequent infection in pregnant women and newborns. Methodology: A prospective study was performed to determine the prevalence of GBS colonization in the vagina and rectum of pregnant women and the antibiotic susceptibility pattern of the isolates. We also aimed to identify risk factors associated with GBS colonization. The vaginal and rectal swabs were inoculated in Todd-Hewitt broth and later subcultured on blood agar for isolation of GBS. Results: A total of 300 pregnant women were enrolled in the study. GBS strains were isolated from seven out of 300 patients, corresponding to a colonization rate of 2.3%. Of the seven patients carrying GBS, isolates were cultured only from vaginal swabs in two cases (28.6%), only from rectal swabs in two cases (28.6%) from both vaginal and rectal swabs in three cases (42.9%). Heavy colonization was present only in 42.9% (3/7) of antenatal women. None of the seven isolates were resistant to penicillin or clindamycin, while one isolate (14.3%) was resistant to erythromycin and five isolates (71.4%) were resistant to tetracycline. Multigravid women and those with previous spontaneous abortion were more frequently colonized by GBS. Conclusion: The GBS colonization rate in our study was low. No resistance to penicillin or clindamycin was seen, while the majority of the isolates were resistant to tetracycline.

scholarly journals Serotype Distribution, Population Structure, and Antimicrobial Resistance of Group B Streptococcus Strains Recovered from Colonized Pregnant Women

2016 ◽  
Vol 55 (2) ◽  
pp. 412-422 ◽  
Author(s):  
Sarah Teatero ◽  
Patricia Ferrieri ◽  
Irene Martin ◽  
Walter Demczuk ◽  
Allison McGeer ◽  
...  
Keyword(s):  
Population Structure ◽  
Pregnant Women ◽  
Antimicrobial Agents ◽  
Vaccine Development ◽  
Group B Streptococcus ◽  
Tetracycline Resistance ◽  
The United States ◽  
High Rate ◽  
Content Type ◽  
Group B

ABSTRACTUsing serotyping, multilocus sequence typing, and whole-genome sequencing (WGS) of selected strains, we studied the population structure of 102 group BStreptococcus(GBS) isolates prospectively sampled in 2014 from vaginal/rectal swabs of healthy pregnant women in metropolitan Toronto, Canada. We also determined the susceptibilities of each of the colonizing isolates to penicillin, erythromycin, clindamycin, tetracycline, and other antimicrobial agents. Overall, we observed a high rate of tetracycline resistance (89%) among colonizing GBS isolates. We found resistance to erythromycin in 36% of the strains, and 33% were constitutively or inducibly resistant to clindamycin. The most frequently identified serotypes were III (25%), Ia (23%), and V (19%). Serotype IV accounted for 6% of the colonizing isolates, a rate consistent with that observed among patients with invasive GBS infections in metropolitan Toronto. The majority of serotype IV isolates belonged to sequence type (ST)459, a tetracycline-, erythromycin-, and clindamycin-resistant ST first identified in Minnesota, which is considered to be the main driver of serotype IV GBS expansion in North America. WGS revealed that ST459 isolates from Canada are clonally related to colonizing and invasive ST459 organisms circulating in regions of the United States. We also used WGS to study recombination in selected colonizing strains from metropolitan Toronto, which revealed multiple episodes of capsular switching. Present and future circulating GBS organisms and their genetic diversity may influence GBS vaccine development.

scholarly journals A composite transposon associated with erythromycin and clindamycin resistance in group B Streptococcus

2007 ◽  
Vol 56 (7) ◽  
pp. 947-955 ◽  
Author(s):  
Karen M. Puopolo ◽  
David C. Klinzing ◽  
Michelle P. Lin ◽  
Derek L. Yesucevitz ◽  
Michael J. Cieslewicz
Keyword(s):  
Genetic Basis ◽  
Southern Hybridization ◽  
Rapd Analysis ◽  
Random Amplified Polymorphic Dna ◽  
Group B Streptococcus ◽  
Macrolide Resistance ◽  
Chromosomal Site ◽  
Streptococcal Species ◽  
Group B ◽  
Us Cities

Group B Streptococcus (GBS) resistant to erythromycin and clindamycin has been isolated with increasing frequency since the mid-1990s. This work studied GBS isolates from three US cities to determine the genetic basis of the macrolide resistance phenotype. ermB genes were amplified from five isolates collected in Boston, Pittsburgh and Seattle from infant and adult sources. Gene-walking methods were used to determine the chromosomal location of ermB and to identify associated genes. Southern mapping and random amplified polymorphic DNA (RAPD) analyses were used to distinguish the isolates. The ermB gene was present on the chromosome within a composite Tn917/Tn916-like transposon similar to one identified in Streptococcus pneumoniae. Four strains from Boston and Pittsburgh were serotype V and identical by Southern hybridization and RAPD analysis. The Seattle isolate was serotype Ib, with different patterns on RAPD analysis and Southern mapping. The composite transposon was integrated at an identical chromosomal site in all five isolates. The presence of this composite transposon in both GBS and pneumococci suggests that ermB-mediated macrolide resistance in streptococci may be due to the horizontal transfer of a mobile transposable element, and raises concern for further dissemination of high-grade erythromycin and clindamycin resistance among streptococcal species.

scholarly journals Group B streptococcus colonisation in pregnant women at Dr. George Mukhari Hospital, South Africa

2016 ◽  
Vol 31 (3) ◽  
pp. 74-78
Author(s):  
M. C. Monyama ◽  
J. Y. Bolukaoto ◽  
M. O. Chukwu ◽  
M. R.B. Maloba ◽  
S. R. Moyo ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Group B Streptococcus ◽  
Age Groups ◽  
Agar Plate ◽  
Broth Culture ◽  
Culture Methods ◽  
Enrichment Broth ◽  
Colonisation Rate ◽  
Vaginal Swabs ◽  
Group B

The aim of the study was to estimate group B streptococcus (GBS) colonisation in pregnant mothers using selective enrichment broth and solid media for culturing GBS. Vaginal and rectal swabs were collected from 413 pregnant women for GBS culture at recruitment stage. Direct plating and enrichment broth culture methods were compared by using the same swab samples. The swabs were cultured on colistin nalidixic agar (CNA) plate and incubated at 37°C and examined after 18-24 h. The samples which were culture negative on a CNA agar plate were then inoculated into a Todd-Hewitt enrichment broth to recover any GBS present that was not recovered on the solid agar. With the CNA agar plate, the samples were cultured separately to enable identification of colonised sites such as vaginal sites or rectal sites. Rectal and vaginal swabs were inoculated into Todd-Hewitt enrichment broth at the same time in the same tube. The GBS colonisation rate in pregnant women was 30.9% (128/413). The CNA agar plate recovered 45.3% (58/128) of the GBS isolates, whereas 54.7% (70/128) isolates were recovered from Todd-Hewitt broth. Pregnant women of various ages were found to be at risk of GBS colonisation. The colonisation rate was however highest among women of 25–29 age groups as compared with other age groups. Detection of group B streptococcus improved when both rectal and vaginal swabs were collected for laboratory analysis. The simultaneous use of Todd-Hewitt broth and CNA plate also improved the yield of group B streptococcus.

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