Genital carriage of the genus Haemophilus in pregnancy: species distribution and antibiotic susceptibility

Abstract

Recent reports have hypothesized that colonization of the maternal genital tract with noncapsulated Haemophilus influenzae could result in neonatal invasive disease. In this study, genital carriage of the genus Haemophilus was investigated in 510 pregnant women attending an Italian hospital for routine controls. Overall, vaginal carriage of the genus Haemophilus was 9.0 % (46/510). A high colonization rate with Haemophilus parainfluenzae (37/510, 7.3 %) was found; other species, such as Haemophilus pittmaniae (7/510, 1.4 %) and Haemophilus haemolyticus (2/510, 0.4 %), were detected for the first time in the genital flora by 16S rRNA gene sequencing. Notably, no H. influenzae was identified, in agreement with previous investigations indicating that this species is rarely isolated from the genito-urinary tract of pregnant women. No antibiotic resistance was detected in H. pittmaniae and H. haemolyticus, but quite a high degree of ampicillin (10/37, 27 %) and ciprofloxacin (3/37, 8.1 %) resistance was observed in H. parainfluenzae. Five ampicillin-resistant isolates were b-lactamase producers, whereas five isolates exhibited a b-lactamase-negative ampicillin-resistant (BLNAR) phenotype. Sequencing of penicillin-binding protein 3 revealed that Val511Ala, Asn526Ser, Ala530Ser and Thr574Ala changes were associated with BLNAR phenotypes. Two ciprofloxacin-resistant isolates carried substitutions in both GyrA (Ser84Phe and Asp88Tyr) and ParC (Ser84Tyr and Met198Leu); the other ciprofloxacin-resistant isolate had substitutions in ParC, only (Ser138Thr and Met198Leu). In conclusion, ,10 % of pregnant women carried a species of Haemophilus in their genital tract. The emergence of non-b-lactamase-mediated resistance in genital H. parainfluenzae is a matter of concern because of the risk of mother-tobaby transmission.

Porphyromonas gingivalisand adverse pregnancy outcome

“…Although the literature to date is relatively sparse, H. parainfluenzae is also a species of concern with respect to mother-to-infant infections and APO [44][45][46][47]. Our findings further support the hypothesis that P. gingivalis-induced dysbiosis results in an oral microbiome profile that permits colonization of potential pathogens and favors an increase in population proportion of resident opportunistic pathogens, increasing the overall risk of microbial infection-associated APOs.…”

Molecular Characterization of Fluoroquinolone-ResistantHaemophilus parainfluenzaeClinical Isolates in Spain

“…[15][16][17] According to this, mutation analysis of QRDRs showed that all strains in this study carried changes at the same positions of GyrA (Ser84 and Asp88) and ParC (at Ser84). The amino acid substitutions found are shown in Table 1.…”

“…Ser84Phe has been reported previously in H. parainfluenzae linked to resistance to fluoroquinolones, and Ser84Tyr has been detected in H. parasuis isolates. 5,[16][17][18] All strains showed the Asp88Tyr substitution also found frequently in quinolone-resistant Haemophilus spp. isolates, including H. parainfluenzae.…”

Mechanisms of antibiotic resistance inHaemophilus parainfluenzae

“…The bacterium is notorious for β-lactamase production, and its β-lactamase producing ability is typically mediated by transferable plasmids. 17,[24][25][26] H. parainfluenzae is also considered as the origin and reservoir for the dissemination of β-lactamase-carrying plasmids to other bacterial species. 27 The β-lactamases detected include the TEM-1 and TEM-15 types, which are usually associated with plasmids.…”

“…Some of the substitutions detected included Ser84Phe and Asp88Tyr in gyrA, Ser84Phe, Ser84Leu, Ser84Tyr, Ser138Thr and Met198Leu in parC, and Asp420Asn and Ala451Ser in parE. Of the studies that investigated the involvement of plasmid mediated resistance genes (qnrA, qnrB, qnrS, qnrC, qnrD, qnrVC, qepA and aac(6′)-Ib-cr genes), 15,17,19,20,34 only one detected aac(6′)-Ib-cr in four isolates of H. parainfluenzae.…”