Virulence genes and antimicrobial susceptibility of lactose-negative and lactose-positive strains of Escherichia coli isolated from pregnant women and neonates

Abstract

Escherichia coli can cause serious infections in the neonates and pregnant women. Although E. coli is widely studied, E. coli lactose-negative (lac−) strains have been rarely described before. So, the aim of this study was to compare lac− and lactose-positive (lac+) E. coli strains in respect of antimicrobial susceptibility and the frequency of virulence genes (VGs). The study included 58 lac+ and 58 lac− E. coli strains isolated from pregnant women and neonates. Culture and the results of biochemical reactions were conducted for lac− and lac+ E. coli identification and differentiation. Disc diffusion test was performed to study the antimicrobial susceptibility of the isolates, and PCR was used to detect VGs. Resistance to at least one of the tested antibiotics was found among 14 (25.9%) E. coli lac+ and in 26 (44.9%) E. coli lac− strains. Both lac+ and lac− E. coli strains were mostly resistant to ampicillin (22.4 and 39.7%) and ticarcillin (20.7 and 39.7%). None of the tested strains produced extended-spectrum β-lactamases (ESBLs). Genes fimH, fimA, iutA, sfa/foc, neuC, ibeA, and hlyF were detected, respectively, in 96.6, 82.8, 32.8, 24.1, 22.4, 12.1, and 6.9% of lac+ E. coli strains and in 94.8, 86.2, 48.3, 19.0, 8.6, 8.6, and 1.7% of lac− strains. The antimicrobial susceptibility and the pathogenic potential of both tested groups of E. coli strains are similar. Therefore, omitting E. coli lac− strains as a potential etiological agent of infections may pose a threat to the health and life of both mothers and neonates.

Virulence-associated genes and antibiotic susceptibility among vaginal and rectal Escherichia coli isolates from healthy pregnant women in Poland

“…All VEC and REC isolates were susceptible to amoxicillin-clavulanic acid, piperacillin-tazobactam, cefepime, ertapenem, imipenem, meropenem, aztreonam, amikacin, netilmicin, and tigecycline. Similar results were also obtained in the authors’ earlier study (Kaczmarek et al 2011 , 2017 ). Similarly, as in this study, Barcaite et al ( 2012 ) revealed that all of pregnant women’s strains were susceptible to amikacin and imipenem and meropenem.…”

“…In the available literature, information about the frequency of hlyF gene (hemolysin F) in strains isolated from pregnant women could not be found. The percentage of E. coli strains with hlyF gene similar to obtained one in this study was obtained in a previous study (Kaczmarek et al 2017 ).…”

“…In this study, the highest percentage of VEC and REC isolates was resistant to ticarcillin (33%), ampicillin (29%), and piperacillin (26%). Similar percentage (30.2%) of isolates resistant to ticarcillin was isolated from pregnant women and neonates in a previous study (Kaczmarek et al 2017 ). The percentage of E. coli isolates resistant to ampicillin similar to that obtained in this study was reported by Meyn and Hillier ( 1997 ) (27%) and Barcaite et al ( 2012 ) (25.9%).…”

“…In this and in previous study (Kaczmarek et al 2011 , 2017 ), no ESBL-positive isolates were detected among the examined E. coli . Sáez-López et al ( 2016a ) found the presence of ESBLs only in one (0.8%) VEC isolate from a pregnant woman.…”

Multi-Drug Resistance Pattern of Lactose Non-Fermenting <i>Escherichia coli</i> as Causative Agent of Urine Tract Infections in Luanda, Angola

“…Historically been reported that up to 10% of E. coli can be "atypical" non-lactose fermenting. Lactose non-fermenting E. coli has a number of virulence factors and exhibit antibiotic resistance [6]. Now there is not a lot of data about lactose non-fermenting E. coli as the etiological agent of urinary tract infection, while the Gram-negative, non-fermenting multi-resistant bacilli make the treatment of these organisms very difficult and expensive [7].…”