Clinical relevance of colonization with antimicrobial-resistant bacteria (AMRB) and methicillin susceptible Staphylococcus aureus (MSSA) for mothers during pregnancy

[Therapy-relevant antibiotic resistances in a One Health context]

One Health refers to a concept that links human, animal, and environmental health. In Germany, there is extensive data on antibiotic resistance (AMR) and multidrug-resistant (micro)organisms (MDRO) in human and veterinary medicine, as well as from studies in various environmental compartments (soil, water, wastewater). All these activities are conducted according to different specifications and standards, which makes it difficult to compare data. A focus on AMR and MDRO of human therapeutic importance is helpful to provide some guidance. Most data are available across sectors on methicillin-resistant Staphylococcus aureus (MRSA) and multiresistant Enterobacterales such as Escherichia coli and Klebsiella pneumoniae. Here, the trends of resistance are heterogeneous. Antibiotic use leads to MRE selection, which is well documented. Success in minimizing antibiotic use has also been demonstrated in recent years in several sectors and could be correlated with success in containing AMR and MDRO (e.g., decrease in MRSA in human medicine). Sector-specific measures to reduce the burden of MDRO and AMR are also necessary, as not all resistance problems are linked to other sectors. Carbapenem resistance is still rare, but most apparent in human pathogens. Colistin resistance occurs in different sectors but shows different mechanisms in each. Resistance to antibiotics of last resort such as linezolid is rare in Germany, but shows a specific One Health correlation. Efforts to harmonize methods, for example in the field of antimicrobial susceptibility testing and genome-based pathogen and AMR surveillance, are an important first step towards a better comparability of the different data collections.

Vancomycin Pharmacokinetics in a Pregnancy Rat Model

Vancomycin usage is often unavoidable in pregnant patients; however, literature suggests vancomycin can cross the placental barrier and reach the fetus. Understanding the mass transit of vancomycin to the fetus is important in pregnancy. We aimed to (i) identify a relevant population pharmacokinetic (PK) model for vancomycin in pregnancy and (ii) estimate PK parameters and describe the mass transit of vancomycin from mother to pup kidneys. Pregnant Sprague-Dawley rats (i.e., trimester 1 and trimester 3) received 250 mg/kg vancomycin once daily for three days through intravenous injection via an internal jugular vein catheter. Vancomycin concentrations in maternal plasma and pup kidneys were quantified via liquid chromatography-tandem mass spectrometry (LC-MS/MS). Multiple compartment models were fitted and assessed using a nonparametric approach with Pmetrics. A total of 10 vancomycin-treated rats and 48 pups contributed PK data. A 3-compartment model adjusted for trimester fit the data well (maternal plasma Bayesian, observed versus predicted R² = 0.978; pup kidney Bayesian, observed versus predicted R² = 0.999). The mean rate constant for vancomycin mass transit to the pup kidney was 0.72 h^-1 for trimester 1 dams and 0.75 h^-1 for trimester 3 dams. Median vancomycin concentrations in pup kidneys from trimester 3 were significantly higher than those in trimester 1 (8.62 versus 0.36 μg/mL, P < 0.001). Vancomycin transited to the fetus from the mother and was; kidney accumulation differed by trimester. This model may be useful for a translational understanding of vancomycin distribution in pregnancy to ensure efficacious and safe doses to both mother and fetus.

Prevalence and clinical relevance of colonization with methicillin-resistant Staphylococcus aureus in the obstetric population

BACKGROUND AND AIMS

Routine screening for Methicillin-Resistant Staphylococcus aureus (MRSA) in pregnant women is common practice in many hospitals. However, little is known on its prevalence and clinical relevance in this population. In this prospective longitudinal study, we aimed to investigate the MRSA prevalence in our obstetric population, the rate of vertical transmission of MRSA and the potential clinical relevance of MRSA colonization for both mother and child. A possible correlation between GBS and MRSA colonization was also investigated.

MATERIALS AND METHODS

MRSA screening samples were collected at 35-37 weeks of gestation (from mother), at delivery and at discharge (from mother and newborn). All samples were analyzed by conventional microbiological methods and MRSA strains were subjected to spa-typing to investigate genetic similarity. The medical records of all positive mother-child pairs were analyzed to detect the occurrence of clinical infection in the postpartum period.

RESULTS

679 mother-child pairs were included between June 2014 and July 2016. Maternal MRSA positivity rate was 1.3% at 35-37 weeks (vaginal/anorectal), 3.1% at delivery (nose/throat) and 3.6% at discharge (nose/throat). MRSA positivity in neonates was 0.3% at delivery and increased to 3% at discharge (nose/umbilicus). Almost all MRSA positive children were born to MRSA positive mothers (OR 120.40, 95% CI: 38.42-377.32). Genetic similarity of the MRSA strains found in mother and child was illustrated for all but one case. 57.7% of the cases of MRSA colonization in our cohort were associated with livestock exposure. 31% of the MRSA positive mothers developed an infectious complication in the postpartum period. No neonatal infectious complications were observed. GBS positivity was not a predictive factor for MRSA colonization in our cohort.

CONCLUSION

The rate of MRSA colonization (overall 4.3%) in our obstetric population is similar to that described in the literature and that of the general population admitted to our hospital in the same period. Maternal MRSA colonization appeared to be an important risk factor for neonatal colonization. Whereas mothers were at higher risk of developing infectious morbidity in the postpartum period, no neonatal infectious complications were observed. We observed no correlation between GBS and MRSA colonization.

Vaginal colonization with antimicrobial-resistant bacteria among women in labor in central Uganda: prevalence and associated factors

BACKGROUND

According to WHO ( CISMAC. Centre for Intervention Science in Maternal and Child health), the antimicrobial resistant bacteria considered to be clinically most important for human health and earmarked for surveillance include extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae, carbapenem-resistant bacteria, methicillin-resistant (MRSA) and, macrolide-lincosamide-streptogramin B -resistant vancomycin-resistant (VRSA) Staphylococcus aureus and vancomycin-resistant Enterococcus (VRE). If these bacteria are carried in the female genital tract, they may be transmitted to the neonate causing local or systemic neonatal infections that can be difficult to treat with conventionally available antimicrobials. In order to develop effective treatment strategies, there is need for updated information about the prevalence of colonization with important antimicrobial-resistant pathogens.

OBJECTIVE

We sought to estimate the prevalence of vaginal colonization with potentially pathogenic and clinically important AMR bacteria among women in labour in Uganda and to identify factors associated with colonization.

METHODS

We conducted a cross-sectional study among HIV-1 and HIV-2 negative women in labour at three primary health care facilities in Uganda. Drug susceptibility testing was done using the disk diffusion method on bacterial isolates cultured from vaginal swabs. We calculated the prevalence of colonization with potentially pathogenic and clinically important AMR bacteria, in addition to multidrug-resistant (MDR) bacteria, defined as bacteria resistant to antibiotics from ≥ 3 antibiotic classes.

RESULTS

We found that 57 of the 1472 enrolled women (3.9% prevalence; 95% Confidence interval [CI] 3.0%, 5.1%) were colonized with ESBL-producing Enterobacteriaceace, 27 (1.8%; 95% CI 1.2%, 2.6%) were colonized with carbapenem-resistant Enterobacteriaceae, and 85 (5.8%; 95% CI 4.6%, 7.1%) were colonized with MRSA. The prevalence of colonization with MDR bacteria was high (750/1472; 50.9%; 95% CI 48.4%, 53.5%). Women who were ≥ 30 years of age had higher odds of being colonized with MDR bacteria compared to women aged 20-24 years (OR 1.6; 95% CI 1.1, 2.2).

CONCLUSION

Most of the women included in our study were vaginally colonized with potentially pathogenic MDR and other clinically important AMR bacteria. The high prevalence of colonization with these bacteria is likely to further increase the incidence of difficult-to-treat neonatal sepsis.

Rising prevalence of multidrug-resistant uropathogenic bacteria from urinary tract infections in pregnant women

Objectives

This study aimed to determine the prevalence of urinary tract infections (UTI) in pregnant women and characterise the uropathogenic bacterial strains associated with symptomatic and asymptomatic bacteriuria in Lahore, Pakistan.

Methods

Between December 2018 and June 2019, we analysed the uropathogenic bacterial strains from midstream urine samples in 80 pregnant women. The age of the pregnant women ranged from 19 to 45 years, and they resided in urban and rural areas. We also recorded socioeconomic factors in this cohort. The isolated strains were phenotypically identified and evaluated for multiple drug resistance (MDR) patterns against recommended antimicrobial drugs.

Results

Of the 80 pregnant women, 65 had UTI, reflecting an 81% prevalence of UTI in women during pregnancy. The majority of participants aged 24–35 years, were multipara, and were in their third trimester. Results showed that 67 uropathogenic bacterial strains belonged to Escherichia (31%), Klebsiella (23%), Pseudomonas (16%), Streptococcus (4%), Enterococcus (4%), Staphylococcus (4%), and Proteus (3%) genera, as identified using biochemical characterisation. The highest overall resistance of Escherichia was seen against amoxicillin, pipemidic acid, and ampicillin; for Klebsiella against pipemidic acid, ampicillin, and cefotaxime; and for Pseudomonas against ciprofloxacin and cefotaxime. The three strains with the highest MDR were identified using 16S rRNA as Pseudomonas aeruginosa strain UA17, Escherichia coli strain UA32, and Klebsiella pneumoniae strain UA47.

Conclusion

In this study, the MDR uropathogenic strains showed the highest resistance pattern. The alarming signs of MDR uropathogenic infections are infrequently addressed and thus, urgent attention to this matter is essential.

Characterization of aerobic vaginitis in late pregnancy in a Chinese population: A STROBE-compliant study

This study aimed to analyze the clinical characteristics, responsible pathogens, and antibiotic sensitivity of aerobic vaginitis (AV) infection in women in late pregnancy in western China.We enrolled 246 pregnancy with AV (≥35 weeks gestation) and 204 reproductive non-pregnancy with AV from West China between January 2019 and December 2019. Then, bacterial culture, identification and antibiotic sensitivity testing were performed. Subsequently, we retrospectively analyzed the vaginal microbiota of 250 healthy pregnant women with no AV and compared the maternal features and pregnancy outcomes.Regarding bacterial diversity, Streptococcus and Lactobacillus were highly abundant in women with AV in late pregnancy, whereas Staphylococcus spp. and other bacteria were significantly more abundant in reproductive non-pregnant women with AV. In addition, 82.5% (343/416) of the single isolate comprised Escherichia coli, group B Streptococcus, Enterococcus faecalis, and Staphylococcus aureus. Among the top 4 isolates, 13.4% (46/343) were multidrug-resistant, but all isolates were highly susceptible to nitrofurantoin. Escherichia coli was 100% susceptible to amikacin, meropenem, ertapenem, and imipenem (100%, 157/157), and gram-positive cocci were 100% (186/186) susceptible to vancomycin and linezolid. Finally, we found that pregnant women with AV had high rates of histories of vaginitis, premature rupture of membranes and neonatal infection.Our study reveals new insights into AV infection during pregnancy and highlights the different vaginal bacterial microbiome compositions between pregnant and reproductive non pregnant women with AV, these results may translate to treatments that are more cost-effective than current standard treatments.