Next Generation and Other Sequencing Technologies in Diagnostic Microbiology and Infectious Diseases

Next-generation sequencing (NGS) technologies have become increasingly available for use in the clinical microbiology diagnostic environment. There are three main applications of these technologies in the clinical microbiology laboratory: whole genome sequencing (WGS), targeted metagenomics sequencing and shotgun metagenomics sequencing. These applications are being utilized for initial identification of pathogenic organisms, the detection of antimicrobial resistance mechanisms and for epidemiologic tracking of organisms within and outside hospital systems. In this review, we analyze these three applications and provide a comprehensive summary of how these applications are currently being used in public health, basic research, and clinical microbiology laboratory environments. In the public health arena, WGS is being used to identify and epidemiologically track food borne outbreaks and disease surveillance. In clinical hospital systems, WGS is used to identify multi-drug-resistant nosocomial infections and track the transmission of these organisms. In addition, we examine how metagenomics sequencing approaches (targeted and shotgun) are being used to circumvent the traditional and biased microbiology culture methods to identify potential pathogens directly from specimens. We also expand on the important factors to consider when implementing these technologies, and what is possible for these technologies in infectious disease diagnosis in the next 5 years.

Investigation of SARS-CoV-2 Epsilon Variant and Hospitalization Status by Genomic Surveillance in a Single Large Health System During the 2020-2021 Winter Surge in Southern California

OBJECTIVES

This study aimed to assess whether the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Epsilon variant (B.1.429/427) is more virulent, leading to more hospitalization and more severe disease requiring intensive care unit (ICU) admission.

METHODS

SARS-CoV-2 genomic surveillance was performed on respiratory samples from 231 unique patients, collected at a single large health system in Southern California between November 2020 and March 2021 during the winter surge.

RESULTS

The frequencies of the Epsilon variant among outpatients, hospitalized patients, and ICU patients were indifferent.

CONCLUSIONS

Our study suggests that the Epsilon variant is not associated with increased hospitalization and ICU admission.

Genomic epidemiology of the Los Angeles COVID-19 outbreak and the early history of the B.1.43 strain in the USA

Background

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused global disruption of human health and activity. Being able to trace the early outbreak of SARS-CoV-2 within a locality can inform public health measures and provide insights to contain or prevent viral transmission. Investigation of the transmission history requires efficient sequencing methods and analytic strategies, which can be generally useful in the study of viral outbreaks.

Methods

The County of Los Angeles (hereafter, LA County) sustained a large outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). To learn about the transmission history, we carried out surveillance viral genome sequencing to determine 142 viral genomes from unique patients seeking care at the University of California, Los Angeles (UCLA) Health System. 86 of these genomes were from samples collected before April 19, 2020.

Results

We found that the early outbreak in LA County, as in other international air travel hubs, was seeded by multiple introductions of strains from Asia and Europe. We identified a USA-specific strain, B.1.43, which was found predominantly in California and Washington State. While samples from LA County carried the ancestral B.1.43 genome, viral genomes from neighboring counties in California and from counties in Washington State carried additional mutations, suggesting a potential origin of B.1.43 in Southern California. We quantified the transmission rate of SARS-CoV-2 over time, and found evidence that the public health measures put in place in LA County to control the virus were effective at preventing transmission, but might have been undermined by the many introductions of SARS-CoV-2 into the region.

Conclusion

Our work demonstrates that genome sequencing can be a powerful tool for investigating outbreaks and informing the public health response. Our results reinforce the critical need for the USA to have coordinated inter-state responses to the pandemic.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08488-7.

Genomic Characterizations of Clade III Lineage of Candida auris, California, USA

Candida auris is an emerging multidrug-resistant yeast. We describe an ongoing C. auris outbreak that began in October 2019 in Los Angeles, California, USA. We used genomic analysis to determine that isolates from 5 of 6 patients belonged to clade III; 4 isolates were closely related.

Massively scaled-up testing for SARS-CoV-2 RNA via next-generation sequencing of pooled and barcoded nasal and saliva samples

Frequent and widespread testing of members of the population who are asymptomatic for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is essential for the mitigation of the transmission of the virus. Despite the recent increases in testing capacity, tests based on quantitative polymerase chain reaction (qPCR) assays cannot be easily deployed at the scale required for population-wide screening. Here, we show that next-generation sequencing of pooled samples tagged with sample-specific molecular barcodes enables the testing of thousands of nasal or saliva samples for SARS-CoV-2 RNA in a single run without the need for RNA extraction. The assay, which we named SwabSeq, incorporates a synthetic RNA standard that facilitates end-point quantification and the calling of true negatives, and that reduces the requirements for automation, purification and sample-to-sample normalization. We used SwabSeq to perform 80,000 tests, with an analytical sensitivity and specificity comparable to or better than traditional qPCR tests, in less than two months with turnaround times of less than 24 h. SwabSeq could be rapidly adapted for the detection of other pathogens.

Retrospective Detection of SARS-CoV-2 in Symptomatic Patients prior to Widespread Diagnostic Testing in Southern California

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused one of the worst pandemics in recent history. Few reports have revealed that SARS-CoV-2 was spreading in the United States as early as the end of January. In this study, we aimed to determine if SARS-CoV-2 had been circulating in the Los Angeles (LA) area at a time when access to diagnostic testing for coronavirus disease 2019 (COVID-19) was severely limited.

Methods

We used a pooling strategy to look for SARS-CoV-2 in remnant respiratory samples submitted for regular respiratory pathogen testing from symptomatic patients from November 2019 to early March 2020. We then performed sequencing on the positive samples.

Results

We detected SARS-CoV-2 in 7 specimens from 6 patients, dating back to mid-January. The earliest positive patient, with a sample collected on January 13, 2020 had no relevant travel history but did have a sibling with similar symptoms. Sequencing of these SARS-CoV-2 genomes revealed that the virus was introduced into the LA area from both domestic and international sources as early as January.

Conclusions

We present strong evidence of community spread of SARS-CoV-2 in the LA area well before widespread diagnostic testing was being performed in early 2020. These genomic data demonstrate that SARS-CoV-2 was being introduced into Los Angeles County from both international and domestic sources in January 2020.

Swab-Seq: A high-throughput platform for massively scaled up SARS-CoV-2 testing

The rapid spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is due to the high rates of transmission by individuals who are asymptomatic at the time of transmission^1,2. Frequent, widespread testing of the asymptomatic population for SARS-CoV-2 is essential to suppress viral transmission. Despite increases in testing capacity, multiple challenges remain in deploying traditional reverse transcription and quantitative PCR (RT-qPCR) tests at the scale required for population screening of asymptomatic individuals. We have developed SwabSeq, a high-throughput testing platform for SARS-CoV-2 that uses next-generation sequencing as a readout. SwabSeq employs sample-specific molecular barcodes to enable thousands of samples to be combined and simultaneously analyzed for the presence or absence of SARS-CoV-2 in a single run. Importantly, SwabSeq incorporates an in vitro RNA standard that mimics the viral amplicon, but can be distinguished by sequencing. This standard allows for end-point rather than quantitative PCR, improves quantitation, reduces requirements for automation and sample-to-sample normalization, enables purification-free detection, and gives better ability to call true negatives. After setting up SwabSeq in a high-complexity CLIA laboratory, we performed more than 80,000 tests for COVID-19 in less than two months, confirming in a real world setting that SwabSeq inexpensively delivers highly sensitive and specific results at scale, with a turn-around of less than 24 hours. Our clinical laboratory uses SwabSeq to test both nasal and saliva samples without RNA extraction, while maintaining analytical sensitivity comparable to or better than traditional RT-qPCR tests. Moving forward, SwabSeq can rapidly scale up testing to mitigate devastating spread of novel pathogens.

Bladder bacterial diversity differs in continent and incontinent women: a cross-sectional study

BACKGROUND

Since the discovery of the bladder microbiome (urobiome), interest has grown in learning whether urobiome characteristics have a role in clinical phenotyping and provide opportunities for novel therapeutic approaches for women with common forms of urinary incontinence.

OBJECTIVE

This study aimed to test the hypothesis that the bladder urobiome differs among women in the control cohort and women affected by urinary incontinence by assessing associations between urinary incontinence status and the cultured urobiome.

STUDY DESIGN

With institutional review board oversight, urine specimens from 309 adult women were collected through transurethral catheterization. These women were categorized into 3 cohorts (continent control, stress urinary incontinence [SUI], and urgency urinary incontinence [UUI]) based on their responses to the validated Pelvic Floor Distress Inventory (PFDI) questionnaire. Among 309 women, 150 were in the continent control cohort, 50 were in the SUI cohort, and 109 were in the UUI cohort. Symptom severity was assessed by subscale scoring with the Urinary Distress Inventory (UDI), subscale of the Pelvic Floor Distress Inventory. Microbes were assessed by expanded quantitative urine culture protocol, which detects the most common bladder microbes (bacteria and yeast). Microbes were identified to the species level by matrix-assisted laser desorption and ionization time-of-flight mass spectrometry. Alpha diversity indices were calculated for culture-positive samples and compared across the 3 cohorts. The correlations of UDI scores, alpha diversity indices, and species abundance were estimated.

RESULTS

Participants had a mean age of 53 years (range 22-90); most were whites (65%). Women with urinary incontinence were slightly older (control, 47; SUI, 54; UUI, 61). By design, UDI symptom scores differed (control, 8.43 [10.1]; SUI, 97.95 [55.36]; UUI, 93.71 [49.12]; P<.001). Among 309 participants, 216 (70%) had expanded quantitative urine culture-detected bacteria; furthermore, the urinary incontinence cohorts had a higher detection frequency than the control cohort (control, 57%; SUI, 86%; UUI, 81%; P<.001). In addition, the most frequently detected species among the cohorts were as follows: continent control, Lactobacillus iners (12.7%), Streptococcus anginosus (12.7%), L crispatus (10.7%), and L gasseri (10%); SUI, S anginosus (26%), L iners (18%), Staphylococcus epidermidis (18%), and L jensenii (16%); and UUI, S anginosus (30.3%), L gasseri (22%), Aerococcus urinae (18.3%), and Gardnerella vaginalis (17.4%). However, only Actinotignum schaalii (formerly Actinobaculum schaalii), A urinae, A sanguinicola, and Corynebacterium lipophile group were found at significantly higher mean abundances in 1 of the urinary incontinence cohorts when compared with the control cohort (Wilcoxon rank sum test; P<.02), and no individual genus differed significantly between the 2 urinary incontinence cohorts. Both urinary incontinence cohorts had increased alpha diversity similar to continent control cohort with indices of species richness, but not evenness, strongly associated with urinary incontinence.

CONCLUSION

In adult women, the composition of the culturable bladder urobiome is associated with urinary incontinence, regardless of common incontinence subtype. Detection of more unique living microbes was associated with worsening incontinence symptom severity. Culturable species richness was significantly greater in the urinary incontinence cohorts than in the continent control cohort.

Vaginal estrogen therapy is associated with increased Lactobacillus in the urine of postmenopausal women with overactive bladder symptoms

BACKGROUND

Previous work has shown that the vaginal microbiome decreases in Lactobacillus predominance and becomes more diverse after menopause. It has also been shown that estrogen therapy restores Lactobacillus dominance in the vagina and that topical estrogen is associated with overactive bladder symptom improvement. We now know that the bladder contains a unique microbiome and that increased bladder microbiome diversity is associated with overactive bladder. However, there is no understanding of how quickly each pelvic floor microbiome responds to estrogen or if those changes are associated with symptom improvement.

OBJECTIVE

This study aimed to determine if estrogen treatment of postmenopausal women with overactive bladder decreases urobiome diversity.

STUDY DESIGN

We analyzed data from postmenopausal participants in 2 trials (NCT02524769 and NCT02835846) who chose vaginal estrogen as the primary overactive bladder treatment and used 0.5 g of conjugated estrogen (Premarin cream; Pfizer, New York City, NY) twice weekly for 12 weeks. Baseline and 12-week follow-up data included the Overactive Bladder questionnaire, and participants provided urine samples via catheter, vaginal swabs, perineal swabs, and voided urine samples. Microbes were detected by an enhanced culture protocol. Linear mixed models were used to estimate microbiome changes over time. Urinary antimicrobial peptide activity was assessed by a bacterial growth inhibition assay and correlated with relative abundance of members of the urobiome.

RESULTS

In this study, 12 weeks of estrogen treatment resulted in decreased microbial diversity within the vagina (Shannon, P=.047; Richness, P=.043) but not in the other niches. A significant increase in Lactobacillus was detected in the bladder (P=.037) but not in the vagina (P=.33), perineum (P=.56), or voided urine (P=.28). The change in Lactobacillus levels in the bladder was associated with modest changes in urgency incontinence symptoms (P=.02). The relative abundance of the genus Corynebacterium correlated positively with urinary antimicrobial peptide activity after estrogen treatment.

CONCLUSION

Estrogen therapy may change the microbiome of different pelvic floor niches. The vagina begins to decrease in diversity, and the bladder experiences a significant increase in Lactobacillus levels; the latter is correlated with a modest improvement in the symptom severity subscale of the Overactive Bladder questionnaire.

Carbapenem Resistant Aeromonas hydrophila Carrying bla cphA7 Isolated From Two Solid Organ Transplant Patients

Aeromonas hydrophila resides in a variety of aquatic environments. Infections with A. hydrophila mainly occur after contact with fresh or brackish water. Nosocomial infections with A. hydrophila can also occur. A. hydrophila infections can be difficult to treat due to both intrinsic and acquired antimicrobial resistance (AMR) mechanisms. In 2018–19, we isolated multi-drug resistant (MDR) A. hyrodphila from two solid organ transplant patients with intra-abdominal infections. We aimed to characterize their AMR mechanisms and to determine their genetic relatedness to aid epidemiological investigation. We performed whole genome sequencing (WGS) using Illumina MiSeq and Nanopore MinIon on 3 A. hydrophila isolates, with one isolate from Patient A (blood) and two isolates from Patient B (abdominal and T-tube fluid, isolated 2 weeks apart). Phenotypic assays included: Broth Microdilution (BMD), Modified Hodge Test (MHT), Modified Carbapenem Inactivation Method (mCIM), and EDTA Carbapenem Inactivation Method (eCIM). Data analyses were performed using CLCbio and Geneious. AMR genomic analysis revealed that all three isolates possess chromosomally encoded genes including bla_OXA−12(oxacillinase), bla_cepS(AmpC), and bla_cphA7(metallo-beta-lactamase). All isolates tested strongly positive by MHT and mCIM, but only Patient B's second isolate (after 2 weeks of meropenem treatment) tested positive by eCIM. More intriguingly, Patient B's first isolate (before meropenem treatment) tested falsely susceptible to carbapenems by BMD, suggesting bla_cphA7 gene was not expressed constitutively. Phylogenetic analysis showed the two isolates from Patient B were highly similar with only 1 SNP difference. The isolate from Patient A only differed from Patient B's isolates by 35 and 36 SNPs, respectively, suggesting close genetic relatedness. Further epidemiological investigation is undergoing. We report the first cases of CphA-mediated carbapenem resistant A. hydrophila in the U.S. It is concerning that 1 out of 3 isolates tested falsely susceptible to carbapenems by BMD despite clear carbapenemase production shown by strongly positive MHT and mCIM. In both cases, meropenem was initially used to treat the patients. Clinicians and microbiologists in the US should be aware of the emerging MDR Aeromonas nosocomial infections and the potential false carbapenem susceptible results due to CphA-type carbapenemase, which may be induced during treatment.

Epidemiological and Genomic Analysis of SARS-CoV-2 in 10 Patients From a Mid-Sized City Outside of Hubei, China in the Early Phase of the COVID-19 Outbreak

A novel coronavirus known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of the ongoing Coronavirus Disease 2019 (COVID-19) pandemic. In this study, we performed a comprehensive epidemiological and genomic analysis of SARS-CoV-2 genomes from 10 patients in Shaoxing (Zhejiang Province), a mid-sized city outside of the epicenter Hubei province, China, during the early stage of the outbreak (late January to early February, 2020). We obtained viral genomes with >99% coverage and a mean depth of 296X demonstrating that viral genomic analysis is feasible via metagenomics sequencing directly on nasopharyngeal samples with SARS-CoV-2 Real-time PCR C_t values <28. We found that a cluster of four patients with travel history to Hubei shared the exact same virus with patients from Wuhan, Taiwan, Belgium, and Australia, highlighting how quickly this virus spread to the globe. The virus from another cluster of two family members living together without travel history but with a sick contact of a confirmed case from another city outside of Hubei accumulated significantly more mutations (9 SNPs vs. average 4 SNPs), suggesting a complex and dynamic nature of this outbreak. Our findings add to the growing knowledge of the epidemiological and genomic characteristics of SARS-CoV-2 and offers a glimpse into the early phase of this viral infection outside of Hubei, China.

Amplicon-Based Next-Generation Sequencing for Detection of Fungi in Formalin-Fixed, Paraffin-Embedded Tissues: Correlation with Histopathology and Clinical Applications

Invasive fungal infections are increasing in prevalence because of an expanding population of immunocompromised individuals. To reduce morbidity and mortality, it is critical to accurately identify fungal pathogens to guide treatment. Current methods rely on histopathology, fungal culture, and serology, which are often insufficient for diagnosis. Herein, we describe the use of a laboratory-developed internal transcribed spacer-targeted amplicon-based next-generation sequencing (NGS) assay for the identification of fungal etiology in fungal stain-positive formalin-fixed, paraffin-embedded tissues by using Illumina MiSeq. A total of 44 specimens from 35 patients were included in this study, with varying degrees of fungal burden from multiple anatomic sites. NGS identified 20 unique species across the 54 total organisms detected, including 40 molds, 10 yeasts, and 4 dimorphic fungi. The histopathologic morphology and the organisms suspected by surgical pathologist were compared with the organisms identified by NGS, with 100% (44/44) and 93.2% (41/44) concordance, respectively. In contrast, fungal culture only provided an identification in 27.3% (12/44) of specimens. We demonstrated that NGS is a powerful method for accurate and unbiased fungal identification in formalin-fixed, paraffin-embedded tissues. A retrospective evaluation of the clinical utility of the NGS results also suggests this technology can potentially improve both the speed and the accuracy of diagnosis for invasive fungal infections.

The urobiome of continent adult women: a cross-sectional study

OBJECTIVE

To characterise the bladder microbiota of continent adult women.

DESIGN

Cross-sectional study of adult women who contributed catheterised urine samples, completed validated symptom questionnaires, and provided demographic data.

SETTING

US academic medical centre.

POPULATION

Well-characterised continent adult women.

METHODS

Participants contributed symptoms questionnaires, demographic data, and catheterised urine samples that were analysed by enhanced urine culture methodology and 16S rRNA gene sequencing.

MAIN OUTCOME MEASURES

Associations between demographics and microbial community state structures (urotypes, defined by the dominant taxon of each specimen).

RESULTS

The bladder microbiota (urobiome) of a control group of 224 continent women were characterised, demonstrating variability in terms of urotype. The most common urotype was Lactobacillus (19%), which did not differ with any demographic. In contrast, the Gardnerella (P < 0.001) and Escherichia (P = 0.005) urotypes were more common in younger and older women, respectively.

CONCLUSIONS

For urobiome research, enhanced culture methods and/or DNA sequencing are the preferred techniques for bacterial detection. The interpretation of clinical tests, such as the standard urine culture, should incorporate the knowledge that some women have Gardnerella or Escherichia urotypes without evidence of any clinical disorder. Clinical care strategies should preserve or restore the beneficial effects of the native urobiome, as disruption of that microbial community could result in unintended vulnerability to uropathogen invasion or opportunistic pathogen overgrowth. Longitudinal studies of urobiome responses to therapies should be encouraged.

TWEETABLE ABSTRACT

In continent adult women bladder microbiome composition differs by age, with relevance for clinical practice.

Culturing of female bladder bacteria reveals an interconnected urogenital microbiota

Metagenomic analyses have indicated that the female bladder harbors an indigenous microbiota. However, there are few cultured reference strains with sequenced genomes available for functional and experimental analyses. Here we isolate and genome-sequence 149 bacterial strains from catheterized urine of 77 women. This culture collection spans 78 species, representing approximately two thirds of the bacterial diversity within the sampled bladders, including Proteobacteria, Actinobacteria, and Firmicutes. Detailed genomic and functional comparison of the bladder microbiota to the gastrointestinal and vaginal microbiotas demonstrates similar vaginal and bladder microbiota, with functional capacities that are distinct from those observed in the gastrointestinal microbiota. Whole-genome phylogenetic analysis of bacterial strains isolated from the vagina and bladder in the same women identifies highly similar Escherichia coli, Streptococcus anginosus, Lactobacillus iners, and Lactobacillus crispatus, suggesting an interlinked female urogenital microbiota that is not only limited to pathogens but is also characteristic of health-associated commensals.

The female bladder seems to harbor a poorly characterized indigenous microbiota. Here, the authors isolate and genome-sequence 149 bacterial strains from catheterized urine of 77 women, generating a culture collection representing two thirds of the bacterial diversity within the samples.

Microorganisms Identified in the Maternal Bladder: Discovery of the Maternal Bladder Microbiota

Objective  The objective of this study was to characterize the bladder microbiota in pregnancy. Methods  A prospective observational study of 51 pregnant women, admitted to a tertiary care hospital, who underwent straight catheterization urine collection or transurethral Foley catheter placement. 16S rRNA gene sequencing and enhanced quantitative urine culture assessed the maternal bladder microbiota with comparisons made to standard urine culture results. Results  Enhanced quantitative urine culture and 16S rRNA gene sequencing detected bacteria in the majority of participants. Lactobacillus and Gardnerella were the most commonly detected microbes. In contrast, standard urine culture had a 100% false-negative rate and failed to detect several known or emerging urinary pathogens. Conclusion  There are live bacteria in the bladders of most pregnant women. This challenges the definition of asymptomatic bacteriuria.

Genomes of Gardnerella Strains Reveal an Abundance of Prophages within the Bladder Microbiome

Bacterial surveys of the vaginal and bladder human microbiota have revealed an abundance of many similar bacterial taxa. As the bladder was once thought to be sterile, the complex interactions between microbes within the bladder have yet to be characterized. To initiate this process, we have begun sequencing isolates, including the clinically relevant genus Gardnerella. Herein, we present the genomic sequences of four Gardnerella strains isolated from the bladders of women with symptoms of urgency urinary incontinence; these are the first Gardnerella genomes produced from this niche. Congruent to genomic characterization of Gardnerella isolates from the reproductive tract, isolates from the bladder reveal a large pangenome, as well as evidence of high frequency horizontal gene transfer. Prophage gene sequences were found to be abundant amongst the strains isolated from the bladder, as well as amongst publicly available Gardnerella genomes from the vagina and endometrium, motivating an in depth examination of these sequences. Amongst the 39 Gardnerella strains examined here, there were more than 400 annotated prophage gene sequences that we could cluster into 95 homologous groups; 49 of these groups were unique to a single strain. While many of these prophages exhibited no sequence similarity to any lytic phage genome, estimation of the rate of phage acquisition suggests both vertical and horizontal acquisition. Furthermore, bioinformatic evidence indicates that prophage acquisition is ongoing within both vaginal and bladder Gardnerella populations. The abundance of prophage sequences within the strains examined here suggests that phages could play an important role in the species’ evolutionary history and in its interactions within the complex communities found in the female urinary and reproductive tracts.

Genome sequences and annotation of two urinary isolates of E. coli

The genus Escherichia includes pathogens and commensals. Bladder infections (cystitis) result most often from colonization of the bladder by uropathogenic E. coli strains. In contrast, a poorly defined condition called asymptomatic bacteriuria results from colonization of the bladder with E. coli strains without symptoms. As part of an on-going attempt to identify and characterize the newly discovered female urinary microbiota, we report the genome sequences and annotation of two urinary isolates of E. coli: one (E78) was isolated from a female patient who self-reported cystitis; the other (E75) was isolated from a female patient who reported that she did not have symptoms of cystitis. Whereas strain E75 is most closely related to an avian extraintestinal pathogen, strain E78 is a member of a clade that includes extraintestinal strains often found in the human bladder. Both genomes are uncommonly rich in prophages.

The Interaction between Enterobacteriaceae and Calcium Oxalate Deposits

Background

The role of calcium oxalate crystals and deposits in UTI pathogenesis has not been established. The objectives of this study were to identify bacteria present in pediatric urolithiasis and, using in vitro and in vivo models, to determine the relevance of calcium oxalate deposits during experimental pyelonephritis.

Methods

Pediatric kidney stones and urine were collected and both cultured and sequenced for bacteria. Bacterial adhesion to calcium oxalate was compared. Murine kidney calcium oxalate deposits were induced by intraperitoneal glyoxalate injection and kidneys were transurethrally inoculated with uropathogenic Escherichia coli to induce pyelonephritis

Results

E. coli of the family Enterobacteriaceae was identified in patients by calcium oxalate stone culture. Additionally Enterobacteriaceae DNA was sequenced from multiple calcium oxalate kidney stones. E. coli selectively aggregated on and around calcium oxalate monohydrate crystals. Mice inoculated with glyoxalate and uropathogenic E. coli had higher bacterial burdens, increased kidney calcium oxalate deposits and an increased kidney innate immune response compared to mice with only calcium oxalate deposits or only pyelonephritis.

Conclusions

In a murine model, the presence of calcium oxalate deposits increases pyelonephritis risk, likely due to preferential aggregation of bacteria on and around calcium oxalate crystals. When both calcium oxalate deposits and uropathogenic bacteria were present, calcium oxalate deposit number increased along with renal gene transcription of inner stone core matrix proteins increased. Therefore renal calcium oxalate deposits may be a modifiable risk factor for infections of the kidney and urinary tract. Furthermore, bacteria may be present in calcium oxalate deposits and potentially contribute to calcium oxalate renal disease.

Incontinence medication response relates to the female urinary microbiota

INTRODUCTION AND HYPOTHESIS

Many adult women have resident urinary bacteria (urinary microbiome/microbiota). In adult women affected by urinary urgency incontinence (UUI), the etiologic and/or therapeutic role of the urinary microbiome/microbiota remains unknown. We hypothesized that microbiome/microbiota characteristics would relate to clinically relevant treatment response to UUI medication per os.

METHODS

Adult women initiating medication treatment orally for UUI and a comparator group of unaffected women were recruited in a tertiary care health-care system. All participants provided baseline clinical data and urine samples. Women with UUI were given 5 mg solifenacin, with potential dose escalation to 10 mg for inadequate UUI symptom control at 4 weeks. Additional data and urine samples were collected from women with UUI at 4 and 12 weeks. The samples were assessed using 16S ribosomal RNA (rRNA) gene sequencing and enhanced quantitative urine culturing. The primary outcome was treatment response as measured by the validated Patient Global Symptom Control (PGSC) questionnaire. Clinically relevant UUI symptom control was defined as a 4 or 5 score on the PGSC.

RESULTS

Diversity and composition of the urinary microbiome/microbiota of women with and without UUI differed at baseline. Women with UUI had more bacteria and a more diverse microbiome/microbiota. The clinical response to solifenacin in UUI participants was related to baseline microbiome/microbiota, with responders more likely to have fewer bacteria and a less diverse community at baseline. Nonresponders had a more diverse community that often included bacteria not typically found in responders.

CONCLUSIONS

Knowledge of an individual's urinary microbiome/microbiota may help refine UUI treatment. Complementary tools, DNA sequencing, and expanded urine culture provide information about bacteria that appear to be related to UUI incontinence status and treatment response in this population of adult women.