Antimicrobial susceptibility of Gram-negative uropathogens isolated from obstetric patients

Comparison of obstetric to institutional antibiogram as an approach to advance antimicrobial stewardship in maternal care

OBJECTIVE

To create an antibiogram derived exclusively from our obstetric population and compare the clinical isolates and susceptibilities to our institutional antibiogram.

METHODS

Data collected by the University Hospital Clinical Microbiology Laboratory in SSC Soft from 01/01/2018 to 12/31/2018 was used to generate our institutional antibiogram. For comparison, we created an obstetric (OB) antibiogram using all clinical isolates collected during the same time interval from OB triage, labor & delivery, antepartum and postpartum wards. The antibiotic susceptibilities of the OB clinical isolates were compared to the institutional clinical isolates.

RESULTS

In total, we identified 929 clinical isolates from our OB population in 2018. Urine was the predominant source of clinical isolates (76.3%). The remaining sources included wound (10.1%), genital (9.0%), blood and other fluids (4.6%). Escherichia coli (E. coli) accounted for nearly half of all isolates (48.7%) followed by Group B Streptococcus (10.7%), Enterococcus spp. (9%), and Klebsiella pneumoniae (7.2%). There was no difference in susceptibilities of Gram-positive organisms in the OB antibiogram compared to the institutional antibiogram. Conversely, common Gram-negative organisms demonstrated less antibiotic resistance in the OB antibiogram compared to the institutional antibiogram. Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis were significantly more susceptible in the OB antibiogram compared to the institutional antibiogram to most antimicrobials tested.

CONCLUSION

Compared to our institutional antibiogram, gram-negative clinical isolates in our OB population exhibit less antibiotic resistance. Creation of an OB-specific antibiogram, which more accurately reflects antibiotic resistance patterns within our unique patient population, may promote appropriate antimicrobial use by assisting in more informed antibiotic selection and limit unnecessary use of broad-spectrum antibiotics.

K1 Antigen Is Associated with Different AST Profile in Escherichia coli: A One-Month-Long Pilot Study

Escherichia coli is responsible for diseases of varying severity. The “K” antigen designates the capsular polysaccharides on the bacterial surface, which are mostly similar to those of highly pathogenic bacteria. The K1 antigen is often found in pathogenic E. coli. Aim: While the published studies on the AST profile of K1-positive E. coli have focused on pregnant women or newborns, this study aimed to characterize the AST profile of K1-positive E. coli independently of the clinical sample of isolation. Over a 4-week-long period, all patients hospitalized/consulting at the Poitiers University Hospital presenting a determined AST on E. coli were prospectively included to define their K1-status (Pastorex Meningitis) and to collect the clinical (age/sex) or biological metadata (AST/MIC). Among the 296 included samples, no differential representation was observed between K1 results regarding sample nature. K1-negative results were associated with multiple antibiotic-resistance (12.3% vs. 33.0%; p < 0.01). AST phenotypes differed between these groups, with a higher proportion of K1-negativity among resistant strains, especially on β-lactams (ureidopenicillin, 25.8% vs. 14.9%; and ampicillin/inhibitor, 50.0% vs. 26.8%; p < 0.05) or quinolone (19.8% vs. 7.0%) and sulfamethoxazole-trimethoprim (30.2% vs. 12.3%) (p < 0.01). This study analyzed E. coli ASTs in clinical samples of all types, regarding their K1-antigen status.

Accuracy of simple urine tests for diagnosis of urinary tract infections in low-risk pregnant women

Anatomic and physiological alterations during pregnancy predispose pregnant women to urinary tract infections (UTI). This study aimed to identify the accuracy of the simple urine test for UTI diagnosis in low-risk pregnant women. Diagnostic test performance was conducted in Botucatu, SP, involving 230 pregnant women, between 2006 and 2008. Results showed 10% UTI prevalence. Sensitivity, specificity and accuracy of the simple urine test were 95.6%, 63.3% and 66.5%, respectively, in relation to UTI diagnoses. The analysis of positive (PPV) and negative (NPV) predictive values showed that, when a regular simple urine test was performed, the chance of UTI occurrence was small (NPV 99.2%). In view of an altered result for such a test, the possibility of UTI existence was small (PPV 22.4%). It was concluded that the accuracy of the simple urine test as a diagnostic means for UTI was low, and that performing a urine culture is essential for appropriate diagnosis.