668 - Multidrug-Resistant Gram-Negative Bacteria and Antibiotic Resistance Genes in Preterm Breastmilk
Saturday, April 29, 2023
3:30 PM – 6:00 PM ET
Poster Number: 668 Publication Number: 668.241
Sourabh Dutta, Postgraduate Institute of Medical Education and Research, Chandigarh, Chandigarh, India; Manisha Biswal, Postgraduate Institute of Medical Education and Research, Chandigarh, Chandigarh, India; Pallab .. Ray, PGIMER, Chandigarh, Chandigarh, India; Ambika Sharma, PGIMER, Chandigarh, Chandigarh, India; Anwesha Chakraborty, Post graduate institute of medical education and research, Chandigarh, Chandigarh, India; vanita suri, PGIMER, chandigarh, Chandigarh, India
Professor Postgraduate Institute of Medical Education and Research Chandigarh, Chandigarh, India
Background: Mothers delivering preterm are often exposed to broad-spectrum antibiotics. This may select out potentially pathogenic multidrug-resistant (MDR) bacteria, such as extended-spectrum beta-lactamase (ESBL) producing and carbapenem-resistant gram-negative bacteria (CRGNB) in breastmilk. This could contribute to a neonatal gut resistome. Objective: Preterm milk samples were studied to determine the presence of ESBL-producing GNB and CRGNB, and the associated antibiotic resistance genes (ARGs). Design/Methods: Mothers who delivered at 28-34 weeks and had received peri-partum antibiotics were enrolled at ≤10 days postpartum. A breastmilk sample was aseptically collected and cultured. Bacteria were identified using matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), focusing on a panel of gram-negative neonatal pathogens of interest, such as Escherichia coli, Klebsiella pneumoniae etc. Antimicrobial sensitivity was tested by the Vitek2 system. Standard definitions were used for ESBL and CRGNB. In addition, DNA was extracted directly from the samples, and multiplex PCR assays run to detect 15 common ARGs for ESBL and CRGNB. Neonates were followed up to record episodes of gram-negative sepsis, if any. In the event of episodes due to organisms similar to those in the breastmilk (species with identical antibiograms), we planned to perform multi-locus sequence typing (MLST) to verify strain identity. Results: Of 130 mothers screened, 100 were enrolled. 10 isolates of potentially pathogenic GNB were grown from 9 breastmilk samples (Escherichia coli= 3, Klebsiella pneumoniae= 4, Pseudomonas aeruginosa =2 and Acinetobacter baumannii =1). Three of them were ESBL producing, 2 CRGNB, one both ESBL and CRGNB, and 4 were neither. The prevalence of ARGs associated with ESBL was: blaTEM: 24/100 (24%), blaSHV: 28%, blaOXa-1: 22%, CTX-M1: 24%, CTX-M2: 5%, CTX-M9: 7%, blaACC: 0%, blaFOX: 33%, blaMOX: 2%, blaDHA: 0%, blaCIT: 33%, and blaEBC: 1%. The prevalence of ARGs associated with CRGNB was: blaIMP: 49/100 (49%), blaVIM: 15%, and blaKPC: 3%. One neonate each developed an episode of E coli, K pneumoniae and A baumannii sepsis. However, none was due to a strain with a similar antibiogram as in breastmilk, precluding the need for MLST.
Conclusion(s): There is a high prevalence of ARGs associated with ESBL and CRGNB in preterm breastmilk. A significant proportion has potentially pathogenic ESBL-producing bacteria and CRGNB. No neonate had gram-negative sepsis due to these species. However, among preterm infants, breastmilk intake may contribute to acquiring a gut resistome soon after birth.
