Novel Mutations in a Patient Isolate of Streptococcus agalactiae with Reduced Penicillin Susceptibility Emerging after Long-Term Oral Suppressive Therapy

Longtin, Jean; Vermeiren, Christie; Shahinas, Dea; Tamber, Gurdip Singh; McGeer, Allison; Low, Donald E.; Katz, Kevin; Pillai, Dylan R.

doi:10.1128/aac.01243-10

Cited by 84 publications

(56 citation statements)

References 16 publications

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“…In particular, substitutions of Val405Ala and/or Gln557Glu of PBP2X correlated with increases in the MIC, indicating a reduced PEN susceptibility. Elsewhere, PRGBS possessing substitutions of PBPs (PBP1A, PBP2A, PBP2B, and PBP2X) were isolated from adult patients in Canada (9,10) and the United States (11).…”

Section: Discussionmentioning

confidence: 99%

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Molecular Characteristics of Group B Streptococci Isolated from Adults with Invasive Infections in Japan

et al. 2016

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bStreptococcus agalactiae (group B streptococcus) isolates (n ‫؍‬ 443) obtained from Japanese adults with invasive infections between April 2010 and March 2013 were analyzed for capsular serotype, multilocus sequence type (ST), antibiotic susceptibility, and resistance genes. Among these cases, bacteremia without primary focus was the most common variety of infection (49.9%), followed by cellulitis (12.9%) and pneumonia (9.0%). Concerning patient age (18 to 59, 60 to 69, 70 to 79, 80 to 89, and 90 years old or older), the incidence of pneumonia increased in patients in their 70s and 80s (P < 0.001), while younger patients (18 to 59 and 60 to 69 years old) were more likely to have abscesses (P < 0.05). The mortality rate was 10.2% for all ages. The most common capsular serotype was Ib (39.5%), followed by V (16.0%), III (13.8%), VI (9.5%), and Ia (8.6%). The main ST of serotype Ib strains was ST10, which belonged to clonal complex 10 (88.0%). The predominant clonal complexes of serotypes V and III, respectively, were 1 (78.9%) and 19 (75.4%). Among these isolates, 9 strains (2.0%) were identified as group B streptococci with reduced penicillin susceptibility, reflecting amino acid substitutions in penicillin-binding protein 2X (PBP2X). In addition, 19.2% of all strains possessed mef(A/E), erm(A), or erm(B) genes, which mediate macrolide resistance, while 40.2% of strains were resistant to quinolones resulting from amino acid substitutions in GyrA and ParC. Our data argue strongly for the continuous surveillance of microbial characteristics and judicious antibiotic use in clinical practice.

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Section: Discussionmentioning

confidence: 99%

“…Subsequently, PRGBS isolates were found to possess various PBPs (PBP1A, PBP2A, PBP2B, and PBP2X) among isolates from adult patients in Canada (9,10) and the United States (11).…”

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Molecular Characteristics of Group B Streptococci Isolated from Adults with Invasive Infections in Japan

et al. 2016

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“…revious published reports have shown that group B Streptococcus (GBS) isolates were 100% susceptible to both penicillin (1, 2) and vancomycin (1); however, reduced susceptibilities to penicillin have been documented (3)(4)(5)(6)(7)(8). GBS susceptibilities to clindamycin and erythromycin have varied (2,(9)(10)(11)(12), and data regarding inducible clindamycin resistance are not always reported (2).…”

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Antimicrobial Susceptibilities of Group B Streptococcus Isolates from Prenatal Screening Samples

et al. 2014

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Previous published reports have shown that group B Streptococcus (GBS) isolates were 100% susceptible to both penicillin (1, 2) and vancomycin (1); however, reduced susceptibilities to penicillin have been documented (3)(4)(5)(6)(7)(8). GBS susceptibilities to clindamycin and erythromycin have varied (2,(9)(10)(11)(12), and data regarding inducible clindamycin resistance are not always reported (2). We examined GBS susceptibilities to clindamycin, erythromycin, penicillin, and vancomycin from isolates obtained from prenatal screening samples.Vaginal/rectal ESwab (Copan Diagnostics Inc., Murrieta, CA) samples submitted for routine prenatal GBS screenings were evaluated. GBS was isolated and identified using Strep B Carrot Broth (Hardy Diagnostics, Santa Maria, CA) subcultured to GBS Detect (Hardy Diagnostics, Santa Maria, CA) as previously described (13). GBS Detect is a selective medium, and it allows for the isolation of GBS, including strains that are typically nonhemolytic on sheep blood agar. Immediately following isolation, GBS isolates were subcultured to sheep blood agar plates (Remel, Lenexa, KS) and incubated aerobically for 18 to 20 h at 35°C. Antimicrobial susceptibility testing (AST) was performed according to 2013 CLSI guidelines (14) on 102 GBS isolates using vancomycin and benzylpenicillin G (0.016 to 256 g/ml) Etest strips (bioMérieux, Durham, NC) and on 387 GBS isolates using clindamycin (2 g) and erythromycin (15 g) BBL Sensi-Discs (Becton, Dickinson, and Company, Sparks, MD) placed 12 mm apart to detect inducible clindamycin resistance.A total of 102/102 (100%) GBS isolates examined were susceptible to penicillin and vancomycin (Table 1). Both the MIC 50 and MIC 90 for penicillin were 0.064 g/ml, and both the MIC 50 and MIC 90 for vancomycin were 1.0 g/ml (data not shown). GBS isolates were susceptible to both clindamycin and erythromycin in 195/387 (50.4%) isolates and resistant to both clindamycin and erythromycin in 106/387 (27.4%) isolates (data not shown). An additional 8% (31/387) of isolates had a positive D-test, indicating inducible clindamycin resistance. The overall susceptibilities of GBS isolates to clindamycin were 62.8% (243/387) or 70.8% (274/ 387), accounting for or not accounting for inducible clindamycin resistance, respectively. The overall susceptibility of GBS isolates to erythromycin was 51.7% (200/387) ( Table 1).Current recommendations for GBS in pregnant women include AST of GBS strains isolated from penicillin-allergic women at high risk for anaphylaxis, screening for inducible clindamycin resistance when AST is performed, and reporting GBS isolates with inducible clindamycin resistance as clindamycin resistant (15). However, penicillin allergy may not always be known at the onset of labor. Our laboratory routinely performs clindamycin and erythromycin susceptibility testing on all GBS strains isolated from prenatal screening samples. Here we report rates of susceptibility of GBS to clindamycin, erythromycin, penicillin, and vancomycin that are very similar to those ...

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“…Besides these two key substitutions, multiple amino acid substitutions were also found in PBP 2X, PBP 2B, and PBP 1A among PRGBS isolates, depending on the penicillin MIC levels (6)(7)(8). After our aforementioned study, PRGBS isolates harboring amino acid substitutions in PBPs were also reported in the United States and Canada (9)(10)(11). The prevalence of penicillin nonsusceptibility among GBS isolates from various clinical sources has increased from around 4.5% between 2007 and 2012 to 6.6% in 2013, according to the Japan Nosocomial Infections Surveillance (JANIS) of the Ministry of Health, Labour and Welfare (see http://www.nih-janis.jp).…”

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confidence: 91%

“…PRGBS isolates were reported in the United States and Canada after our first investigation of their emergence and molecular mechanisms, but they are still rare (6)(7)(8)(9)(10)(11). Domestically, our subsequent investigations revealed the increase of PRGBS among clinical GBS isolates, their tendency toward resistance to multiple drugs, and a probable association of such a multidrug-resistant PRGBS clone with nosocomial spread (16).…”

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confidence: 99%

Penicillin-Susceptible Group B Streptococcal Clinical Isolates with Reduced Cephalosporin Susceptibility

Nagano

Toyama

et al. 2014

J Clin Microbiol

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We characterized penicillin-susceptible group B streptococcal (PSGBS) clinical isolates exhibiting no growth inhibition zone around a ceftibuten disk (CTB r PSGBS). The CTB r PSGBS isolates, for which augmented MICs of cefaclor and ceftizoxime were found, shared a T394A substitution in penicillin-binding protein 2X (PBP 2X) and a T567I substitution in PBP 2B, together with an additional G429S substitution in PBP 2X or a T145A substitution in PBP 1A, although the T145A substitution in the transglycosidase domain of PBP 1A would have no effect on the level of resistance to ceftibuten.

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Novel Mutations in a Patient Isolate of Streptococcus agalactiae with Reduced Penicillin Susceptibility Emerging after Long-Term Oral Suppressive Therapy

Cited by 84 publications

References 16 publications

Molecular Characteristics of Group B Streptococci Isolated from Adults with Invasive Infections in Japan

Molecular Characteristics of Group B Streptococci Isolated from Adults with Invasive Infections in Japan

Antimicrobial Susceptibilities of Group B Streptococcus Isolates from Prenatal Screening Samples

Penicillin-Susceptible Group B Streptococcal Clinical Isolates with Reduced Cephalosporin Susceptibility

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