Asymptomatic bacteriuria: prevalence rates of causal microorganisms, etiology of infection in different patient populations, and recent advances in molecular detection

An opportunistic pathogen under stress: how Group B Streptococcus responds to cytotoxic reactive species and conditions of metal ion imbalance to survive

Group B Streptococcus (GBS; also known as Streptococcus agalactiae) is an opportunistic bacterial pathogen that causes sepsis, meningitis, pneumonia, and skin and soft tissue infections in neonates and healthy or immunocompromised adults. GBS is well-adapted to survive in humans due to a plethora of virulence mechanisms that afford responses to support bacterial survival in dynamic host environments. These mechanisms and responses include counteraction of cell death from exposure to excess metal ions that can cause mismetallation and cytotoxicity, and strategies to combat molecules such as reactive oxygen and nitrogen species that are generated as part of innate host defence. Cytotoxicity from reactive molecules can stem from damage to proteins, DNA, and membrane lipids, potentially leading to bacterial cell death inside phagocytic cells or within extracellular spaces within the host. Deciphering the ways in which GBS responds to the stress of cytotoxic reactive molecules within the host will benefit the development of novel therapeutic and preventative strategies to manage the burden of GBS disease. This review summarizes knowledge of GBS carriage in humans and the mechanisms used by the bacteria to circumvent killing by these important elements of host immune defence: oxidative stress, nitrosative stress, and stress from metal ion intoxication/mismetallation.

Induction of human-fetal-membrane remodeling in-vitro by the alpha hemolysin of Escherichia coli

INTRODUCTION

Almost 80% of urinary tract infections during pregnancy are caused by uropathogenic strains of Escherichia coli. Alpha-hemolysin, toxin secreted by them, has a fundamental role in this pathology development. Considering that urinary tract infections are related with premature rupture of fetal membranes, we proposed to evaluate the effects that alpha-hemolysin induces on human-fetal-membranes.

METHODS

Thirteen fetal membranes obtained from elective cesarean sections (>37 weeks) were mounted in a transwell-device generating two independent chambers. To mimic an ascendant-urinary-tract infection, membranes were incubated with different concentrations of pure alpha-hemolysin from the choriodecidual side during 24h. Extensive histological analyses were performed and transepithelial electrical-resistance were determined. Cell viability, metalloproteinase activity and cyclooxygenase-2- gene expression was estimated by lactate-dehydrogenase-release assay, zymography and RT-qPCR, respectively. Finally, four fetal membranes were treated with hemolysin preincubated with polyclonal anti-hemolysin antibodies. Cell viability and metalloproteinase activity were monitored.

RESULTS

After 24 h of treatment, fetal membranes evidenced a structural damage and a decrease in membrane resistance that progressed as the concentration of alpha hemolysin increased. While the amniotic-epithelial-layer remained practically unaffected, the chorion cells manifested an increase in vacuolization and necrosis. In addition, the extracellular matrix exhibited collagen-fiber disorganization, a marked decrease in fiber content, and became thicker in presence of the toxin. Cyclooxigenase-2 expression and metalloproteinase activity were also higher in the treated groups than in untreated ones. Finally, a preincubation of hemolysin with specific antibodies prevented the cytotoxicity on the chorion cells and the increase in metalloproteinase activity.

DISCUSSION

Hemolysin induces structural and molecular changes associated with the remodeling of human-fetal-membranes in-vitro.

Prevalence of Asymptomatic Bacteriuria (ASB) in Pregnant Women in India: A Systematic Review and Meta-Analysis

Background

Asymptomatic bacteriuria is prevalent during pregnancy. If it goes undetected, it can lead to urinary tract infection with severe maternal and neonatal complications. Until date, India does not have any guidelines to test for ASB during pregnancy.

Objective

To estimate the pooled prevalence of asymptomatic bacteriuria in pregnant women at national level in India.

Material and Methods

We searched Medline, Embase, Web of Science, and Google Scholar using search strategy with keyword. Two authors independently assessed the eligibility of study. The checklist of the JBI was used for evaluating the quality of reporting. The extracted data were analyzed, and the results were reported using a random-effects model with 95% confidence interval (CI). Subgroup analysis was conducted for zones of India, parity and trimester. Publication bias is reported as funnel plot.

Result

Pooled prevalence of asymptomatic bacteriuria among pregnant women in India is 13.5% [CI 11.1; 15.8]. Subgroup analysis based on the various geographic zones of the country the pooled prevalence ranged from 9.2% in central zone to 14.8% in south zone. Distribution of prevalence of ASB as per parity was approximately identical. The prevalence of ASB was found to be high in third (21.8%).

Conclusion

The prevalence of ASB is found to be high among Indian pregnant women, especially in third trimester. It is therefore recommended for guideline to screen and treat every pregnant woman for ASB to prevent further complications.

A Multifaceted Intervention and Its Effects on Antibiotic Usage in Norwegian Nursing Homes

We explored the impact of an antibiotic quality improvement intervention across 33 nursing homes (NHs) in one Norwegian county, compared against four control counties. This 12-month multifaceted intervention consisted of three physical conferences, including educational sessions, workshops, antibiotic feedback reports, and academic detailing sessions. We provided clinical guiding checklists to participating NHs. Pharmacy sales data served as a measure of systemic antibiotic use. The primary outcome was a change in antibiotic use in DDD/100 BD from the baseline through the intervention, assessed using linear mixed models to identify changes in antibiotic use. Total antibiotic use decreased by 15.8%, from 8.68 to 7.31 DDD/100BD (model-based estimated change (MBEC): -1.37, 95% CI: -2.35 to -0.41) in the intervention group, albeit not a significantly greater reduction than in the control counties (model-based estimated difference in change (MBEDC): -0.75, 95% CI: -1.91 to 0.41). Oral antibiotic usage for urinary tract infections (UTI-AB) decreased 32.8%, from 4.08 to 2.74 DDD/100BD (MBEC: -1.34, 95% CI: -1.85 to -0.84), a significantly greater reduction than in the control counties (MBEDC: -0.9, 95% CI: -1.28 to -0.31). The multifaceted intervention may reduce UTI-AB use in NHs, whereas adjustments in the implementation strategy may be needed to reduce total antibiotic use.

Mixed Bacterial Growth in Prenatal Urine Cultures; An Investigation into Prevalence, Contributory Factors and the Impact of education-based Interventions

PURPOSE

Undiagnosed urinary tract infections (UTIs) in pregnancy are associated with adverse perinatal outcome. Urine microbiology cultures reported as 'mixed bacterial growth' (MBG) frequently present a diagnostic dilemma for healthcare providers. We investigated external factors contributing to elevated rates of (MBG) within a large tertiary maternity centre in London, UK, and assessed the efficacy of health service interventions to mitigate these.

DESCRIPTION

This prospective, observational study of asymptomatic pregnant women attending their first prenatal clinic appointment aimed to establish (i) the prevalence of MBG in routine prenatal urine microbiology cultures, (ii) the association between urine cultures and the duration to laboratory processing and (iii) ways in which MBG may be reduced in pregnancy. Specifically we assessed the impact of patient-clinician interaction and that of an education package on optimal urine sampling technique.

ASSESSMENT

Among 212 women observed over 6 weeks, the negative, positive and MBG urine culture rates were 66%, 10% and 2% respectively. Shorter duration from urine sample collection to laboratory arrival correlated with higher rates of negative cultures. Urine samples arriving in the laboratory within 3 hours of collection were most likely to be reported as culture negative (74%), and were least likely to be reported as MBG (21%) or culture positive (6%), compared to samples arriving > 6 hours (71%, 14% and 14% respectively; P < 0.001). A midwifery education package effectively reduced rates of MBG (37% pre-intervention vs 19% post-intervention, RR 0.70, 95% CI 0.55 to 0.89). Women who did not receive verbal instructions prior to providing their sample had 5-fold higher rates of MBG (P < 0.001).

CONCLUSION

As many as 24% of prenatal urine screening cultures are reported as MBG. Patient-midwife interaction before urine sample collection and rapid transfer of urine samples to the laboratory within 3 hours reduces the rate of MBG in prenatal urine cultures. Reinforcing this message through education may improve accuracy of test results.

Leveraging diagnostic stewardship within antimicrobial stewardship programmes

Novel diagnostic stewardship in infectious disease consists of interventions that modify ordering, processing, and reporting of diagnostic tests to provide the right test for the right patient, prompting the right action. The interventions work upstream and synergistically with traditional antimicrobial stewardship efforts. As diagnostic stewardship continues to gain public attention, it is critical that antimicrobial stewardship programmes not only learn how to effectively leverage diagnostic testing to improve antimicrobial use but also ensure that they are stakeholders and leaders in developing new diagnostic stewardship interventions within their institutions. This review will discuss the need for diagnostic and antimicrobial stewardship, the interplay of diagnostic and antimicrobial stewardship, evidence of benefit to antimicrobial stewardship programmes, and considerations for successfully engaging in diagnostic stewardship interventions. This article is part of the Antibiotic stewardship Special Issue: https://www.drugsincontext.com/special_issues/antimicrobial-stewardship-a-focus-on-the-need-for-moderation.

Identification of novel factors associated with inappropriate treatment of asymptomatic bacteriuria in acute and long-term care

BACKGROUND

Chart reviews often fall short of determining what drove antibiotic treatment of asymptomatic bacteriuria (ASB). To overcome this shortcoming, we searched providers' free-text for documentation of their decision-making and for misleading signs and symptoms that may trigger unnecessary treatment of ASB.

METHODS

We reviewed a random sample of 10 positive urine cultures per month, per facility, from patients in acute or long-term care wards at 8 Veterans Affairs facilities. Cultures were classified as urinary tract infection (UTI) or ASB, and as treated or untreated. Charts were searched for 13 potentially misleading symptoms, and free-text documentation of providers' decision-making was classified into 5 categories. We used generalized estimating equations logistic regression to identify factors associated with ASB treatment.

RESULTS

One hundred fifty-eight (27.5%) of 575 ASB cases were inappropriately treated with antibiotics. Significant factors associated with inappropriate treatment included: abdominal pain, falls, decreased urine output, urine characteristics, abnormal vital signs, laboratory values, and voiding issues. Providers prescribed an average of 1.4 antimicrobials to patients with ASB, with cephalosporins (41%) and fluoroquinolones (21%) being the most common classes prescribed.

CONCLUSIONS

Chart reviews of providers' decision-making highlighted new factors associated with inappropriate ASB treatment. These findings can help design antibiotic stewardship interventions for ASB.

Magnitude and associated factors of urinary tract infections among adults living with HIV in Ethiopia. Systematic review and meta-analysis

Background

Urinary tract infection is a major public health problem in developing countries among immunocompromized populations where there are limited health-care services. People living with human immunodeficiency virus (HIV) are more likely to develop urinary tract infections (UTI) due to the suppression of their immunity. There is no single representative figure as well as the presence of significant heterogeneity among studies conducted on people living with HIV in Ethiopia. Hence, this study tried to pool the magnitude of UTI among people living with HIV in Ethiopia.

Method

To find relevant studies, researchers looked through Web of Science, Science Direct, PubMed, EMBASE, the Cochrane Library, Google Scholar, and Worldwide Science. The I² statistic was used to examine for heterogeneity among the studies that were included. To evaluate the pooled effect size across studies, a random-effects model was used. The presence of publication bias was determined using a funnel plot and Egger’s regression test. STATA^TM version 14.0 software was used for all statistical analyses.

Results

A total of 7 studies with 2257 participants were included in this meta-analysis. UTI was shown to be prevalent in 12.8% (95% CI: 10.8–14.79, I² = 50.7%) of HIV patients. Being male (0.35, 95% CI:0.14, 1.02), rural residents(OR:1.41,95% CI: 0.85, 2.34), no history of catheterization (OR: 0.35, 95% CI: 0.06, 1.85), had no history of DM (OR:0.84, 95% CI:0.12, 0.597) and having CD4 count greater than 200 (OR:0.36 95% CI: 0.06, 2.35) were the factors which were the associated factors assessed and having association with UTI among people living with HIV but not statistically significant.

Conclusions

In Ethiopia, one in every eight HIV-positive people is at risk of acquiring UTI. Regardless, we looked for a link between sex, residency, CD4, catheterization history, and DM and UTI, but there was none. To avoid this phenomina, every HIV patient should have a UTI examination in every follow-up.

Human Gut Microbiota in Health and Selected Cancers

The majority of the epithelial surfaces of our body, and the digestive tract, respiratory and urogenital systems, are colonized by a vast number of bacteria, archaea, fungi, protozoans, and viruses. These microbiota, particularly those of the intestines, play an important, beneficial role in digestion, metabolism, and the synthesis of vitamins. Their metabolites stimulate cytokine production by the human host, which are used against potential pathogens. The composition of the microbiota is influenced by several internal and external factors, including diet, age, disease, and lifestyle. Such changes, called dysbiosis, may be involved in the development of various conditions, such as metabolic diseases, including metabolic syndrome, type 2 diabetes mellitus, Hashimoto's thyroidis and Graves' disease; they can also play a role in nervous system disturbances, such as multiple sclerosis, Alzheimer's disease, Parkinson's disease, and depression. An association has also been found between gut microbiota dysbiosis and cancer. Our health is closely associated with the state of our microbiota, and their homeostasis. The aim of this review is to describe the associations between human gut microbiota and cancer, and examine the potential role of gut microbiota in anticancer therapy.

Maternal Complications and Adverse Pregnancy Outcomes among Pregnant Women who Acquired Asymptomatic Bacteriuria in Addis Ababa, Ethiopia

In this study, we aimed to document adverse pregnancy outcomes and maternal complications among pregnant women who acquired asymptomatic bacteriuria in Addis Ababa, Ethiopia. We used hospital-based prospective cohort study design in which we followed 44 pregnant women with asymptomatic bacteriuria confirmed by urine culture result of ≥10⁵cfu/ml of urine. We documented adverse pregnancy outcomes and maternal complications in terms of frequency, percentage, mean, and standard deviation. Additionally, we used Pearson's correlation coefficient to investigate associations of selected variables with perinatal death as one of adverse pregnancy outcomes. Of the 44 pregnant women enrolled in the study, complete data was collected from 43 participants with one lost to follow-up. Six (14%) of women developed fever and were treated with antibiotic during pregnancy, 26 (60.5%) delivered with cesarean section, two (4.3%) perinatal deaths within seven days of delivery, one miscarriage, and 4 (9.3%) newborns were found underweight. The mean birth weight of the newborns was 3.1 kg ± 0.60. Almost half 21(48.8%) were born before 37 weeks of gestational age. Fourteen (32.6%) of newborns were born asphyxiated. Twenty-two (51.2%) of newborns developed early neonatal fever within 48 hours of delivery and treated with antibiotic. Correlation coefficient analysis revealed that weight and gestational age of newborns at birth, Apgar score at 1^st and 5^th minutes of birth and miscarriage were positively correlated and significantly associated with perinatal death. The occurrence of unsought pregnancy outcomes were frequent, and substantial number of pregnant women developed maternal complications. Therefore, screening pregnant women for asymptomatic bacteriuria and treating may reduce the possible maternal complications and adverse pregnancy outcomes.

Recurrent Urinary Tract Infections: Unraveling the Complicated Environment of Uncomplicated rUTIs

Urinary tract infections (UTIs) are frequent in humans, affecting the upper and lower urinary tract. Present diagnosis relies on the positive culture of uropathogenic bacteria from urine and clinical markers of inflammation of the urinary tract. The bladder is constantly challenged by adverse environmental stimuli which influence urinary tract physiology, contributing to a dysbiotic environment. Simultaneously, pathogens are primed by environmental stressors such as antibiotics, favoring recurrent UTIs (rUTIs), resulting in chronic illness. Due to different confounders for UTI onset, a greater understanding of the fundamental environmental mechanisms and microbial ecology of the human urinary tract is required. Such advancements could promote the tandem translation of bench and computational studies for precision treatments and clinical management of UTIs. Therefore, there is an urgent need to understand the ecological interactions of the human urogenital microbial communities which precede rUTIs. This review aims to outline the mechanistic aspects of rUTI ecology underlying dysbiosis between both the human microbiome and host physiology which predisposes humans to rUTIs. By assessing the applications of next generation and systems level methods, we also recommend novel approaches to elucidate the systemic consequences of rUTIs which requires an integrated approach for successful treatment. To this end, we will provide an outlook towards the so-called 'uncomplicated environment of UTIs', a holistic and systems view that applies ecological principles to define patient-specific UTIs. This perspective illustrates the need to withdraw from traditional reductionist perspectives in infection biology and instead, a move towards a systems-view revolving around patient-specific pathophysiology during UTIs.

Hemolytic activity and biofilm-formation among clinical isolates of group B streptococcus causing acute urinary tract infection and asymptomatic bacteriuria

Streptococcus agalactiae, also known as group B Streptococcus, is an aetiological agent of urinary tract infection (UTI) in adults, including cystitis, pyelonephritis and asymptomatic bacteriuria (ABU). Whereas ABU-causing S. agalactiae (ABSA) have been shown to grow and achieve higher culture denstity in human urine compared to uropathogenic S. agalactiae (UPSA) other phenotypic distinctions between S. agalactiae isolated from different forms of UTI are not known. Here, we define the hemolytic activities and biofilm-formation of a collection of clinical isolates of UPSA, ABSA and recurrent S. agalactiae bacteriuria (rSAB) strains to explore these phenotypes in the context of clinical history of isolates. A total of 61 UPSA, 184 ABSA, and 47 rSAB isolates were analyzed for relative hemolytic activity by spot assay on blood agar, which was validated using a erythrocyte lysis suspension assay. Biofilm formation was determined by microtiter plate assay with Lysogeny and Todd-Hewitt broths supplemented with 1% glucose to induce biofilm formation. We also used multiplex PCR to analyze isolates for the presence of genes encoding adhesive pili, which contribute to biofilm formation. Comparing the hemolytic activities of 292 isolates showed, surprisingly, that ABSA strains were significantly more likely to be highly hemolytic compared to other strains. In contrast, there were no differences between the relative abilities of strains from the different clinical history groups to form biofilms. Taken together, these findings demonstrate a propensity of S. agalactiae causing ABU to be highly hemolytic but no link between clinical history of UTI strains and ability to form biofilm.

Metabolites Potentiate Nitrofurans in Nongrowing Escherichia coli

Nitrofurantoin (NIT) is a broad-spectrum bactericidal antibiotic used in the treatment of urinary tract infections. It is a prodrug that once activated by nitroreductases goes on to inhibit bacterial DNA, RNA, cell wall, and protein synthesis. Previous work has suggested that NIT retains considerable activity against nongrowing bacteria. Here, we have found that Escherichia coli grown to stationary phase in minimal or artificial urine medium is not susceptible to NIT. Supplementation with glucose under conditions where cells remained nongrowing (other essential nutrients were absent) sensitized cultures to NIT. We conceptualized NIT sensitivity as a multi-input AND gate and lack of susceptibility as an insufficiency in one or more of those inputs. The inputs considered were an activating enzyme, cytoplasmic abundance of NIT, and reducing equivalents required for NIT activation. We systematically assessed the contribution of each of these inputs and found that NIT import and the level of activating enzyme were not contributing factors to the lack of susceptibility. Rather, evidence suggested that the low abundance of reducing equivalents is why stationary-phase E. coli are not killed by NIT and catabolites can resensitize those cells. We found that this phenomenon also occurred when using nitrofurazone, which established generality to the nitrofuran antibiotic class. In addition, we observed that NIT activity against stationary-phase uropathogenic E. coli (UPEC) could also be potentiated through metabolite supplementation. These findings suggest that the combination of nitrofurans with specific metabolites could improve the outcome of uncomplicated urinary tract infections.

Asymptomatic Bacteriuria (ABU) in Elderly: Prevalence, Virulence, Phylogeny, Antibiotic Resistance and Complement C3 in Urine

Background: The incidence of asymptomatic bacteriuria (ABU) increases with age and is most common for persons 80 years of age and above and in elderly living in nursing homes. The distinction between ABU and urinary tract infection (UTI) is often difficult, especially in individuals, who are unable to communicate their symptoms, and there is a lack of objective methods to distinguish between the two entities. This can lead to overuse of antibiotics, which results in the selection and dissemination of antibiotic resistant isolates. Materials and methods: From voided midstream urine samples of 211 participants ≥60 years old from nursing homes, an activity center and a general practitioners clinic, we collected 19 ABU, 16 UTI and 22 control urine samples and compared them with respect to levels of complement component C3 in urine as determined by an ELISA assay relative to creatinine levels in the same urine samples, as measured by a creatinine assay. Further, we studied all Escherichia coli isolates for selected virulence genes by multiplex PCR, and by whole-genome sequencing (WGS) for genotypes and phylogenetic clustering. Antibiotic susceptibility was determined by microtiter broth dilution. Results: We identified a prevalence of ABU of 18.9% in nursing home residents, whereas ABU was only found in 4% of elderly living in the community (p < 0.001). E. coli from ABU patients were significantly more antibiotic resistant than E. coli from UTIs (p = 0.01). Prevalence of classical virulence genes, detected by multiplex PCR, was similar in E. coli isolates from ABU and UTI patients. Whole-genome sequencing of the E. coli isolates showed no specific clustering of ABU isolates compared to UTI isolates. Three isolates from three different individuals from one of the nursing homes showed signs of transmission. We demonstrated a significantly increased level of C3/creatinine ratio in ABU and UTI samples compared to healthy controls; however, there was no significant difference between the ABU and UTI group with respect to C3 level, or virulence factor genes. Conclusion: ABU was significantly more prevalent in the elderly residing in nursing homes than in the elderly living at home. Antibiotic resistance was more prevalent in E. coli from nursing homes than in UTI isolates, but there was no difference in prevalence of virulence associated genes between the two groups and no phylogenetic clustering, as determined by WGS relative to the two types of E. coli bacteriuria. The similar complement C3 response in ABU and UTI patients may indicate that ABU should be reconsidered as an infection albeit without symptoms.

Protocolized Urine Sampling is Associated with Reduced Catheter-associated Urinary Tract Infections: A Pre- and Postintervention Study

Background

Standard urine sampling and testing techniques do not mitigate against detection of colonization, resulting in false positive catheter-associated urinary tract infections (CAUTI). We aimed to evaluate whether a novel protocol for urine sampling and testing reduces rates of CAUTI.

Methods

A preintervention and postintervention study with a contemporaneous control group was conducted at 2 campuses (test and control) of the same academic medical center. The test campus implemented a protocol requiring urinary catheter removal prior to urine sampling from a new catheter or sterile straight catheterization, along with urine bacteria and pyuria screening prior to culture. Primary outcomes were test campus CAUTI rates, compared between each 9-month pre- and postintervention epoch. Secondary outcomes included the percent reductions in CAUTI rates, compared between the test campus and a propensity score–matched cohort at the control campus.

Results

A total of 7991 patients from the test campus were included in the primary analysis, and 4264 were included in the propensity score–matched secondary analysis. In the primary analysis, the number of CAUTI cases per 1000 patients was reduced by 77% (6.6 to 1.5), the number of CAUTI cases per 1000 catheter days was reduced by 63% (5.9 to 2.2), and the number of urinary catheter days per patient was reduced by 37% (1.1 to 0.69; all P values ≤ .001). In the propensity score–matched analysis, the number of CAUTI cases per 1000 patients was reduced by 82% at the test campus, versus 57% at the control campus; the number of CAUTI cases per 1000 catheter days declined by 68% versus 57%, respectively; and the number of urinary catheter days per patient decreased by 44% versus 1%, respectively (all P values &lt; .001).

Conclusions

Protocolized urine sampling and testing aimed at minimizing contamination by colonization was associated with significantly reduced CAUTI infection rates and urinary catheter days.

Exposure to Moderate Glycosuria Induces Virulence of Group B Streptococcus

To explore whether glycosuria induces virulence of uropathogens, in turn facilitating urinary tract infection (UTI), we exposed group B Streptococcus (GBS) strain 10/84 to human urine plain or with 300 mg/dL glucose (mimicking moderate glycosuria). Exposure to moderate glycosuria significantly augmented bacterial growth, kidney bacterial burden in a mouse model of ascending UTI, and virulence characteristics and expression of corresponding genes. Exposure to glycosuria increased GBS adherence to human bladder epithelial cell line and expression of corresponding PI2a fimbrial gene, antimicrobial peptide LL-37 resistance and bacterial surface charge modulating dltA, and GBS hemolytic ability and expression of genes encoding pore-forming toxins.

Host Cathelicidin Exacerbates Group B Streptococcus Urinary Tract Infection

Group B Streptococcus (GBS) causes frequent urinary tract infection (UTI) in susceptible populations, including individuals with type 2 diabetes and pregnant women; however, specific host factors responsible for increased GBS susceptibility in these populations are not well characterized. Here, we investigate cathelicidin, a cationic antimicrobial peptide, known to be critical for defense during UTI with uropathogenic Escherichia coli (UPEC). We observed a loss of antimicrobial activity of human and mouse cathelicidins against GBS and UPEC in synthetic urine and no evidence for increased cathelicidin resistance in GBS urinary isolates. Furthermore, we found that GBS degrades cathelicidin in a protease-dependent manner. Surprisingly, in a UTI model, cathelicidin-deficient (Camp-/-) mice showed decreased GBS burdens and mast cell recruitment in the bladder compared to levels in wild-type (WT) mice. Pharmacologic inhibition of mast cells reduced GBS burdens and histamine release in WT but not Camp-/- mice. Streptozotocin-induced diabetic mice had increased bladder cathelicidin production and mast cell recruitment at 24 h postinfection with GBS compared to levels in nondiabetic controls. We propose that cathelicidin is an important immune regulator but ineffective antimicrobial peptide against GBS in urine. Combined, our findings may in part explain the increased frequency of GBS UTI in diabetic and pregnant individuals.IMPORTANCE Certain populations such as diabetic individuals are at increased risk for developing urinary tract infections (UTI), although the underlying reasons for this susceptibility are not fully known. Additionally, diabetics are more likely to become infected with certain types of bacteria, such as group B Streptococcus (GBS). In this study, we find that an antimicrobial peptide called cathelicidin, which is thought to protect the bladder from infection, is ineffective in controlling GBS and alters the type of immune cells that migrate to the bladder during infection. Using a mouse model of diabetes, we observe that diabetic mice are more susceptible to GBS infection even though they also have more infiltrating immune cells and increased production of cathelicidin. Taken together, our findings identify this antimicrobial peptide as a potential contributor to increased susceptibility of diabetic individuals to GBS UTI.

Antibiotic resistance patterns of Escherichia coli in migrants vs non-migrants: a study of 14 561 urine samples

BACKGROUND

To investigate the distribution of urine isolates and antibiotic resistance patterns in the predominant uropathogen Escherichia coli in migrant and non-migrant individuals.

METHODS

We linked a cohort consisting of all migrants obtaining residence as refugees or family-reunited migrants in Denmark between January 1993 and December 2015 to hospital urine samples examined from January 2000 to December 2015 at the Department of Microbiology, University Hospital Hvidovre, Denmark. Samples from non-migrant individuals, Danish-born from Danish parents, were included as comparison. Analysis was carried out using multivariate logistic regression.

RESULTS

There were 14 561 first-time urine samples included, with E. coli being the most prevalent bacterial pathogen. Of the identified isolates, 4686/11 737 were E. coli among non-migrants and 1032/2824 among migrants.Sulfamethoxazol-Trimethoprim (SXT) resistance was found in 34.3% (350/1020) of E. coli isolates among migrants and 23.2% (1070/4619) among non-migrant patients [odds ratio (OR) 1.73, 95% confidence interval (CI): 1.47-2.03]. Ciprofloxacin resistance was found in 5.8% (36/618) of isolates among migrants and 2.2% (67/3092) among non-migrants (OR 2.20, 95% CI: 1.37-3.53). Gentamicin (GEN) resistance was seen in 10.8% (61/565) and 4.7% (110/2328) of isolates (OR 2.33, 95% CI:1.63-3.34), Cefuroxime resistance in 8.5% (87/1019) and 3.4% (158/4618) (OR 2.40, 95% CI:1.77-3.24), Ampicillin (AMP) resistance in 51.4% and 40.8% (OR 1.65, 95% CI: 1.42-1.92) and Piperacillin-Tazobactam resistance in 6.9% (30/432) and 4.2% (65/1532) for migrant and non-migrant patients, respectively. When stratifying according to migrant status, family-reunited had higher odds of resistance than refugees for SXT, GEN and AMP.

CONCLUSIONS

Prevalence of antibiotic resistance was significantly higher in E. coli isolates among migrants, both refugees and family-reunited, than non-migrant patients. Differences could not be explained by comorbidity or income. The results emphasize the importance of urine sample testing in both local-born and migrants before antibiotic start-up and point to the benefit of considering migration to secure individual treatment and equal health outcomes.

Antibiotics for asymptomatic bacteriuria in pregnancy

BACKGROUND

Asymptomatic bacteriuria is a bacterial infection of the urine without any of the typical symptoms that are associated with a urinary infection, and occurs in 2% to 15% of pregnancies. If left untreated, up to 30% of mothers will develop acute pyelonephritis. Asymptomatic bacteriuria has been associated with low birthweight and preterm birth. This is an update of a review last published in 2015.

OBJECTIVES

To assess the effect of antibiotic treatment for asymptomatic bacteriuria on the development of pyelonephritis and the risk of low birthweight and preterm birth.

SEARCH METHODS

For this update, we searched the Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) on 4 November 2018, and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials (RCT) comparing antibiotic treatment with placebo or no treatment in pregnant women with asymptomatic bacteriuria found on antenatal screening. Trials using a cluster-RCT design and quasi-RCTs were eligible for inclusion, as were trials published in abstract or letter form, but cross-over studies were not.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias, extracted data, and checked for accuracy. We assessed the quality of the evidence using the GRADE approach.

MAIN RESULTS

We included 15 studies, involving over 2000 women. Antibiotic treatment compared with placebo or no treatment may reduce the incidence of pyelonephritis (average risk ratio (RR) 0.24, 95% confidence interval (CI) 0.13 to 0.41; 12 studies, 2017 women; low-certainty evidence). Antibiotic treatment may be associated with a reduction in the incidence of preterm birth (RR 0.34, 95% CI 0.13 to 0.88; 3 studies, 327 women; low-certainty evidence), and low birthweight babies (average RR 0.64, 95% CI 0.45 to 0.93; 6 studies, 1437 babies; low-certainty evidence). There may be a reduction in persistent bacteriuria at the time of delivery (average RR 0.30, 95% CI 0.18 to 0.53; 4 studies; 596 women), but the results were inconclusive for serious adverse neonatal outcomes (average RR 0.64, 95% CI 0.23 to 1.79, 3 studies; 549 babies). There were very limited data on which to estimate the effect of antibiotics on other infant outcomes, and maternal adverse effects were rarely described. Overall, we judged only one trial at low risk of bias across all domains; the other 14 studies were assessed as high or unclear risk of bias. Many studies lacked an adequate description of methods, and we could only judge the risk of bias as unclear, but in most studies, we assessed at least one domain at high risk of bias. We assessed the quality of the evidence for the three primary outcomes with GRADE software, and found low-certainty evidence for pyelonephritis, preterm birth, and birthweight less than 2500 g.

AUTHORS' CONCLUSIONS

Antibiotic treatment may be effective in reducing the risk of pyelonephritis in pregnancy, but our confidence in the effect estimate is limited given the low certainty of the evidence. There may be a reduction in preterm birth and low birthweight with antibiotic treatment, consistent with theories about the role of infection in adverse pregnancy outcomes, but again, the confidence in the effect is limited given the low certainty of the evidence. Research implications identified in this review include the need for an up-to-date cost-effectiveness evaluation of diagnostic algorithms, and more evidence to learn whether there is a low-risk group of women who are unlikely to benefit from treatment of asymptomatic bacteriuria.

Association of serum vitamin D levels and urinary tract infection in pregnant women: A case control study

OBJECTIVE

Urinary tract infection (UTI) is common during pregnancy and can cause serious complications for the mother and fetus. Vitamin D, is known to have an effect on the urothelium, with immunomodulatory capacity against bacterial infection. This study explored the association between serum vitamin D levels and urinary tract infections in pregnant women.

STUDY DESIGN

In this case control study, 187 participants including, 97 pregnant women diagnosed as a symptomatic UTI (case group) and 90 matched healthy pregnant women (control group) were consecutively enrolled from prenatal care clinic of Imam Reza Hospital in Urmia, North West of Iran. The two groups were matched for trimester and parity, and sexual intercourse. Blood samples were collected from both groups. Chemiluminescent immunoassay (CLIA) was used to evaluate the serum vitamin D levels. We used a binary multivariate unconditional logistic regression approach to evaluate the association between UTI and vitamin D and risk factor of the UTI.

RESULTS

Vitamin D deficiency (less than 20 ng/mL) was diagnosed in 85.7% of case group and 52.2% of control group. The serum vitamin D levels were significantly lower in pregnant women in the case group compared to the control group (12.7 ± 5.9 ng/ml vs 26.05 ± 10.37; p < 0.001). Pregnant women in case group with acute pyelonephritis had significantly lower serum vitamin D levels than those with Cystitis (p < 0.05). The serum vitamin D level of less than 20 ng/ml was the only factor associated with UTI after adjusting for all the confounders in multiple binary logistic regression modeling (AdjOR = 3.67; 95% of CI: 1.19-6.24; p < 0.001).

CONCLUSIONS

Women with vitamin D deficiencies are at increased risk of urinary tract infections during pregnancy. However, further studies are essential to confirm these observed results.

Reconsideration of urine culture for the diagnosis of acute pyelonephritis in children: a new challenging method for diagnosing acute pyelonephritis

Acute pyelonephritis (APN) should be detected and treated as soon as possible to reduce the risk of the development of acquired renal scarring. However, in the medical field, urine culture results are not available or considered when the prompt discrimination of APN is necessary and empirical treatment is started. Furthermore, urine culture cannot discriminate APN among children with febrile urinary tract infection (UTI) (pyelitis, lower UTI with other fever focus). Therefore, the usefulness of urine culture for diagnostic purposes is small and the sampling procedure is invasive. Congenital hypoplastic kidney is the most common cause of chronic kidney injury in children. Thus, it is desirable that a main target be detected as early as possible when imaging studies are performed in children with APN. However, if APN does not recur, no medical or surgical treatment or imaging studies would be needed because the acquired renal scar would not progress further. Therefore, the long-term prognosis of APN in young children, particularly infants, depends on the number of recurrent APN, not other febrile UTI. New methods that enable prompt, practical, and comfortable APN diagnosis in children are needed as alternatives to urinary catheterization for urine culture sampling.

Top 10 evidence-based recommendations from the Brazilian Society of Infectious Diseases for the Choosing Wisely Project

The Choosing Wisely Initiative aims to collect statements from medical societies all over the world on medical interventions that result in no benefit to patients, with the potential to cause harm. In this article we present the views of the Diagnostic Laboratory Group at the Brazilian Society of Infectious Diseases (SBI). Ten experts from SBI were asked to list 10 diagnostic tests that were perceived as unnecessary in the field of infectious diseases. After voting for the more relevant topics, a questionnaire was sent to all SBI members, in order to select for the most important items. A total of 482 votes were obtained, and the top 10 results are shown in this manuscript. The Choosing Wisely statements of SBI should facilitate clinical practice by optimizing the use of diagnostic resources in the field of infectious diseases.

Elevated urine IL-10 concentrations associate with Escherichia coli persistence in older patients susceptible to recurrent urinary tract infections

Background

Age is a significant risk factor for recurrent urinary tract (rUTI) infections, but the clinical picture is often confused in older patients who also present with asymptomatic bacteriuria (ASB). Yet, how bacteriuria establishes in such patients and the factors underpinning and/or driving symptomatic UTI episodes are still not understood. To explore this further a pilot study was completed in which 30 male and female community based older patients (mean age 75y) presenting clinically with ASB / rUTIs and 15 control volunteers (72y) were recruited and monitored for up to 6 months. During this period symptomatic UTI episodes were recorded and urines collected for urinary cytokine and uropathogenic Escherichia coli (UPEC) analyses.

Results

Eighty-six per cent of patients carried E. coli (10² ≥ 10⁵ CFU/ml urine) at some point throughout the study and molecular typing identified 26 different E. coli strains in total. Analyses of urine samples for ten different cytokines identified substantial patient variability. However, when examined longitudinally the pro-inflammatory markers, IL-1 and IL-8, and the anti-inflammatory markers, IL-5 and IL-10, were significantly different in the patient urines compared to those of the controls (P < 0.0001). Furthermore, analysing the cytokine data of the rUTI susceptible cohort in relation to E. coli carriage, showed the mean IL-10 concentration to be significantly elevated (P = 0.04), in patients displaying E. coli numbers ≥10⁵ CFU/ml.

Conclusions

These pilot study data suggest that bacteriuria, characteristic of older rUTI patients, is associated with an immune homeostasis in the urinary tract involving the synthesis and activities of the pro and anti-inflammatory cytokines IL-1, IL-5, IL-8 and IL-10. Data also suggests a role for IL-10 in regulating bacterial persistence.

Asymptomatic bacteriuria in older adults: the most fragile women are prone to long-term colonization

Background

The diagnosis of urinary tract infections (UTIs) in institutionalized older adults is often based on vague symptoms and a positive culture. The high prevalence of asymptomatic bacteriuria (ABU), which cannot be easily discriminated from an acute infection in this population, is frequently neglected, leading to a vast over-prescription of antibiotics. This study aimed to identify subpopulations predisposed to transient or long-term ABU.

Methods

Residents in a long-term care facility were screened for ABU. Mid-stream urine samples were collected during two sampling rounds, separated by 10 weeks, each consisting of an initial and a confirmative follow-up sample.

Results

ABU occurred in approximately 40% of the participants and was mostly caused by Escherichia coli. Long-term ABU (> 3 months) was found in 30% of the subjects. The frailest women with urinary incontinence and dementia had drastically increased rates of ABU and especially long-term ABU. ABU was best predicted by a scale describing the functional independence of older adults.

Conclusions

Institutionalized women with incontinence have ABU prevalence rates of about 80% and are often persistent carriers. Such prevalence rates should be considered in clinical decision making as they devalue the meaning of a positive urine culture as a criterion to diagnose UTIs. Diagnostic strategies are urgently needed to avoid antibiotic overuse and to identify patients at risk to develop upper UTI.

Electronic supplementary material

The online version of this article (10.1186/s12877-019-1181-4) contains supplementary material, which is available to authorized users.

Ibuprofen lacks direct antimicrobial properties for the treatment of urinary tract infection isolates

The high incidence of urinary tract infection (UTI) among women and children, in combination with a lack of antibiotic efficacy with regard to pathogen eradication and recurrence prevention, as well as the negative side effects associated with antibiotics, has led researchers to explore the role of non-steroidal anti-inflammatory drugs as a primary management strategy. The aim of this study was to determine whether ibuprofen (IBU) or one of its major metabolites, 2-carboxyibuprofen (CIBU), could affect the growth and adhesion of the two most common uropathogens, Escherichia coli and Enterococcus faecalis. The bacterial growth and adhesion to the urothelial cells of E. coli UTI89 and E. faecalis 1131 in the presence of physiologically relevant concentrations of IBU and CIBU were assessed. The effect of IBU on bacterial adhesion to urothelial cells was also assessed following exposure to trimethoprim/sulfamethoxazole (TMP/SMX) and nitrofurantoin. Bacterial growth was not affected by IBU. Further, only at high levels of IBU not regularly found in the bladder was there a significant increase in E. faecalis 1131 attachment at growth inhibitory concentrations of TMP/SMX. There was no effect on the attachment of E. faecalis or E. coli to urothelial cells in the presence of nitrofurantoin. These studies indicate that the beneficial effects of IBU for UTI management are likely mediated through its anti-inflammatory properties rather than direct interactions with uropathogens in the bladder.

Treatment of infections caused by multidrug-resistant Gram-negative bacteria: report of the British Society for Antimicrobial Chemotherapy/Healthcare Infection Society/British Infection Association Joint Working Party

The Working Party makes more than 100 tabulated recommendations in antimicrobial prescribing for the treatment of infections caused by multidrug-resistant (MDR) Gram-negative bacteria (GNB) and suggest further research, and algorithms for hospital and community antimicrobial usage in urinary infection. The international definition of MDR is complex, unsatisfactory and hinders the setting and monitoring of improvement programmes. We give a new definition of multiresistance. The background information on the mechanisms, global spread and UK prevalence of antibiotic prescribing and resistance has been systematically reviewed. The treatment options available in hospitals using intravenous antibiotics and in primary care using oral agents have been reviewed, ending with a consideration of antibiotic stewardship and recommendations. The guidance has been derived from current peer-reviewed publications and expert opinion with open consultation. Methods for systematic review were NICE compliant and in accordance with the SIGN 50 Handbook; critical appraisal was applied using AGREE II. Published guidelines were used as part of the evidence base and to support expert consensus. The guidance includes recommendations for stakeholders (including prescribers) and antibiotic-specific recommendations. The clinical efficacy of different agents is critically reviewed. We found there are very few good-quality comparative randomized clinical trials to support treatment regimens, particularly for licensed older agents. Susceptibility testing of MDR GNB causing infection to guide treatment needs critical enhancements. Meropenem- or imipenem-resistant Enterobacteriaceae should have their carbapenem MICs tested urgently, and any carbapenemase class should be identified: mandatory reporting of these isolates from all anatomical sites and specimens would improve risk assessments. Broth microdilution methods should be adopted for colistin susceptibility testing. Antimicrobial stewardship programmes should be instituted in all care settings, based on resistance rates and audit of compliance with guidelines, but should be augmented by improved surveillance of outcome in Gram-negative bacteraemia, and feedback to prescribers. Local and national surveillance of antibiotic use, resistance and outcomes should be supported and antibiotic prescribing guidelines should be informed by these data. The diagnosis and treatment of both presumptive and confirmed cases of infection by GNB should be improved. This guidance, with infection control to arrest increases in MDR, should be used to improve the outcome of infections with such strains. Anticipated users include medical, scientific, nursing, antimicrobial pharmacy and paramedical staff where they can be adapted for local use.

Urinary Tract Infections and Preeclampsia among Pregnant Women Attending Two Hospitals in Mwanza City, Tanzania: A 1:2 Matched Case-Control Study

Urinary tract infection (UTI) and preeclampsia are common among pregnant women and are associated with adverse maternal-fetal and neonatal outcomes. Despite this, limited information exists on the association between UTIs and preeclampsia in Tanzania to guide specific management and thereby averting the adverse outcomes. A 1:2 matched case-control study (by age and gravidity) involving 131 pregnant women with preeclampsia (cases) and 262 without preeclampsia (controls) was conducted. Sociodemographic and clinical information was collected using a questionnaire. Midstream urine samples were collected during admission for culture and antimicrobial susceptibility testing (AST). Out of 393 pregnant women enrolled, 110 (28.0%), 95% CI: 23.8%-32.7%, had significant bacteriuria [cases: 50.4% (66/131) and control: 16.8% (44/262)]. Pregnant women with preeclampsia had 7.7 odds of having significant bacteriuria than those without preeclampsia [OR=7.7, 95% CI (4.11-14.49); p-value <0.001]. Escherichia coli, 50 (45.5%), and Klebsiella spp., 25 (23.6%), predominated, and resistance to gentamicin, ceftriaxone, and piperacillin-tazobactam ranged from 9.0% to 29.0% in these dominant species. Extended spectrum beta lactamases (ESBL) production in Escherichia coli and Klebsiella spp. was 18.0% (9/50) and 15.4% (4/26), respectively. Routine urine culture and AST among pregnant women with preeclampsia should be introduced in the antenatal clinics to ensure prompt management. Delineation of maternal-fetal and neonatal outcomes among pregnant women with preeclampsia and UTIs would be of interest in future studies.

Asymptomatic bacteriuria in pregnancy: systematic reviews of screening and treatment effectiveness and patient preferences

OBJECTIVE

To systematically review screening and treatment effectiveness, and patient preferences, to inform recommendations by the Canadian Task Force on Preventive Health Care on screening for asymptomatic bacteriuria in pregnancy.

DESIGN

We searched multiple databases (inception to September 2017) and grey literature sources for studies on screening effectiveness and patient preferences. For treatment with antibiotics, we searched three databases for systematic reviews and obtained search results of the Cochrane Pregnancy and Childbirth Group's Trials Register to update a Cochrane review. Study selection, risk of bias assessment and evaluation of the quality for each outcome using Grading of Recommendations Assessment, Development and Evaluation was completed independently by two reviewers with consensus. Meta-analysis was conducted when appropriate as were analyses based on planned subgroup variables.

OUTCOMES

For screening and treatment effectiveness: maternal and perinatal mortality, maternal and neonatal sepsis, pyelonephritis, spontaneous abortion, preterm delivery, low birth weight and serious adverse events. Valuation of outcomes for patient preferences.

RESULTS

Four studies compared outcomes before and after the introduction of a screening programme or between different screening programmes. All evidence on screening effectiveness was considered very low quality. Women have conflicting opinions about antibiotic use during pregnancy. Fifteen trials compared antibiotic treatment with no treatment or placebo in women with confirmed bacteriuria. Low-quality evidence found that treatment lowered rates of pyelonephritis (12 trials, relative risk [RR] 0.24; 95% CI 0.13 to 0.42; absolute risk reduction [ARR] 17.6%; number needed to treat [NNT] 6, 95% CI 5 to 7) and low birth weight (seven trials, RR 0.63; 95% CI 0.45 to 0.90; ARR 4.4%; NNT 23, 95% CI 15 to 85).

CONCLUSIONS

Antibiotic treatment for women having significant bacteriuria likely reduces the incidence of pyelonephritis and low birth weight, but we are uncertain about the magnitude of the effect and about the extent to which we can apply these results to asymptomatic populations and screening programmes.

PROSPERO REGISTRATION NUMBER

CRD42016045263.

Advances and Challenges in the Diagnosis and Treatment of Urinary Tract Infections: the Need for Diagnostic Stewardship

PURPOSE OF REVIEW

Urinary tract infections (UTIs), including catheter-associated UTIs, are among the most common bacterial infections in both inpatient and outpatient settings. Diagnosis of true UTI remains a clinical challenge, and excessive antimicrobial treatment of asymptomatic bacteriuria (ASB) or contaminated urine cultures is common.

RECENT FINDINGS

Challenges with the appropriate diagnosis of UTIs include the lack of specific signs and symptoms, no definitive diagnostic criteria, high incidence of ASB, contamination of samples, and frequent lack of indications for ordering urine cultures. Promising interventions include education and feedback, indication requirements when ordering cultures, and use of reflex culture policies that limit urine cultures. Antimicrobial and diagnostic stewardship interventions can work synergistically to decrease ordering of urine cultures without clear indication and prevent excessive antimicrobial administration in patients without clearly defined UTI.

Multicentre evaluation of significant bacteriuria among pregnant women in the cascade of referral healthcare system in North-western Tanzania: Bacterial pathogens, antimicrobial resistance profiles and predictors

OBJECTIVES

The aim of this multicentre study was to evaluate the magnitude of significant bacteriuria (SB) as well as the implicated bacterial pathogens, antimicrobial resistance (AMR) profiles and risk factors for SB among pregnant women attending different levels of healthcare facilities (HCFs) in Tanzania in order to guide antimicrobial therapy and preventive measures.

METHODS

Information on sociodemographic and clinical characteristics, midstream urine culture and antimicrobial susceptibility testing was collected from 1828 pregnant women between March 2016 and May 2017. Data were analysed using STATA v.13.0 software.

RESULTS

The prevalence of SB among pregnant women was 17.7% (323/1828; 95% CI 16.0-19.5%), with a predominance of Escherichia coli (164/323; 50.8%), Klebsiella spp. (55/323; 17.0%) and Staphylococcus aureus (28/323; 8.7%). Moreover, 37.5% (121/323) of bacteria were multidrug-resistant [84.3% (102/121) Gram-negative bacteria and 15.7% (19/121) in Gram-positive bacteria; P<0.001]. Third-generation cephalosporin resistance in E. coli, Klebsiella spp. and other Enterobacteriaceae was 13.4%, 21.8% and 27.5%, respectively, and was higher in strains from a tertiary hospital (OR=3.27, 95% CI 1.02-10.49; P=0.046) compared with lower HCFs. Predictors of SB among pregnant women were lack of formal occupation, current hospital admission and presence of co-morbidities.

CONCLUSIONS

The prevalence of SB among pregnant women in this study was high (17.7%) and was within the same range reported 10 years ago in a single-centre baseline study. However, there is an increase in AMR in the cascade of referral healthcare system, underscoring the need for health facility level-specific antimicrobial stewardship.

Fast, economic and simultaneous identification of clinically relevant Gram-negative species with multiplex real-time PCR

AIM

A newly designed multiplex real-time PCR (rt-PCR) was validated to detect four clinically relevant Gram-negative bacteria (Escherichia coli, Acinetobacter baumannii, Klebsiella pneumoniae and Pseudomonas aeruginosa).

MATERIALS & METHODS

Serial dilutions of genomic DNA were used to determine the limit of detection. Colony PCR was performed with isolates of the four selected species and other species as negative controls. Isolates were characterized genotypically and phenotypically to evaluate the assay.

RESULTS

Specific signals of all target genes were detected with diluted templates comprising ten genomic equivalents. Using colony rt-PCR, all isolates of the target species were identified correctly. All negative control isolates were negative.

CONCLUSION

The genes gad, basC, khe and ecfX can reliably identify these four species via multiplex colony rt-PCR.

Prevalence, antimicrobial susceptibility profile and predictors of asymptomatic bacteriuria among pregnant women in Adigrat General Hospital, Northern Ethiopia

OBJECTIVE

Approach to asymptomatic bacteriuria among pregnant women in Ethiopia is mainly based on clinical grounds and urine strip and microscopy tests. On top of this, the treatment is also on an empirical basis which may leads to an increased antimicrobial resistance. The aim of this study was to assess the prevalence, antimicrobial susceptibility profile and associated factors of asymptomatic bacteriuria among pregnant women attending antenatal clinic in Adigrat Hospital, Northern Ethiopia.

RESULTS

Out of 259 pregnant women included in the study, the prevalence of asymptomatic bacteriuria was at 55 (21.2%). Gram negative bacteria, specifically Escherichia coli were the predominant isolates followed by Klebsiella species and Proteus mirabilis. Of the Gram positive identified bacteria, Staphylococcus aureus was main isolate. Age of the mother (18-25 years old) with [AOR = 8.5, 95% CI (2.2, 32.9)], family income (< 1000 ETB) with [AOR = 7.5, 95% CI = (2.4, 23.1)] and gestational period at 1st trimester [AOR = 11.9, 95% CI (4.4, 32.4)] and 2nd trimester [AOR; 5.6, 95% CI (2.0, 15.5%)] were predictors significantly associated with asymptomatic bacteriuria. All Gram negative isolates were found 100% resistance to Ampicllin. Moreover, all Gram positive isolates were found sensitive to Vancomycin at 100%.

Urine Cytokine and Chemokine Levels Predict Urinary Tract Infection Severity Independent of Uropathogen, Urine Bacterial Burden, Host Genetics, and Host Age

Urinary tract infections (UTIs) are among the most common infections worldwide. Diagnosing UTIs in older adults poses a significant challenge as asymptomatic colonization is common. Identification of a noninvasive profile that predicts likelihood of progressing from urine colonization to severe disease would provide a significant advantage in clinical practice. We monitored colonization susceptibility, disease severity, and immune response to two uropathogens in two mouse strains across three age groups to identify predictors of infection outcome. Proteus mirabilis caused more severe disease than Escherichia coli, regardless of mouse strain or age, and was associated with differences in interleukin-1β (IL-1β), beta interferon (IFN-β), CXCL5 (LIX), CCL5 (RANTES), and CCL2 (MCP-1). In a comparison of responses to infection across age groups, mature adult mice were better able to control colonization and prevent progression to kidney colonization and bacteremia than young or aged mice, regardless of mouse strain or bacterial species, and this was associated with differences in IL-23, CXCL1, and CCL5. A bimodal distribution was noted for urine colonization, which was strongly associated with bladder CFU counts and the magnitude of the immune response but independent of age or disease severity. To determine the value of urine cytokine and chemokine levels for predicting severe disease, all infection data sets were combined and subjected to a series of logistic regressions. A multivariate model incorporating IL-1β, CXCL1, and CCL2 had strong predictive value for identifying mice that did not develop kidney colonization or bacteremia, regardless of mouse genetic background, age, infecting bacterial species, or urine bacterial burden. In conclusion, urine cytokine profiles could potentially serve as a noninvasive decision support tool in clinical practice and contribute to antimicrobial stewardship.

Rapid Growth of Uropathogenic Escherichia coli during Human Urinary Tract Infection

Uropathogenic Escherichia coli (UPEC) strains cause most uncomplicated urinary tract infections (UTIs). These strains are a subgroup of extraintestinal pathogenic E. coli (ExPEC) strains that infect extraintestinal sites, including urinary tract, meninges, bloodstream, lungs, and surgical sites. Here, we hypothesize that UPEC isolates adapt to and grow more rapidly within the urinary tract than other E. coli isolates and survive in that niche. To date, there has not been a reliable method available to measure their growth rate in vivo. Here we used two methods: segregation of nonreplicating plasmid pGTR902, and peak-to-trough ratio (PTR), a sequencing-based method that enumerates bacterial chromosomal replication forks present during cell division. In the murine model of UTI, UPEC strain growth was robust in vivo, matching or exceeding in vitro growth rates and only slowing after reaching high CFU counts at 24 and 30 h postinoculation (hpi). In contrast, asymptomatic bacteriuria (ABU) strains tended to maintain high growth rates in vivo at 6, 24, and 30 hpi, and population densities did not increase, suggesting that host responses or elimination limited population growth. Fecal strains displayed moderate growth rates at 6 hpi but did not survive to later times. By PTR, E. coli in urine of human patients with UTIs displayed extraordinarily rapid growth during active infection, with a mean doubling time of 22.4 min. Thus, in addition to traditional virulence determinants, including adhesins, toxins, iron acquisition, and motility, very high growth rates in vivo and resistance to the innate immune response appear to be critical phenotypes of UPEC strains.

Uropathogenic Escherichia coli (UPEC) strains cause most urinary tract infections in otherwise healthy women. While we understand numerous virulence factors are utilized by E. coli to colonize and persist within the urinary tract, these properties are inconsequential unless bacteria can divide rapidly and survive the host immune response. To determine the contribution of growth rate to successful colonization and persistence, we employed two methods: one involving the segregation of a nonreplicating plasmid in bacteria as they divide and the peak-to-trough ratio, a sequencing-based method that enumerates chromosomal replication forks present during cell division. We found that UPEC strains divide extraordinarily rapidly during human UTIs. These techniques will be broadly applicable to measure in vivo growth rates of other bacterial pathogens during host colonization.

Distinct Signature of Oxylipid Mediators of Inflammation during Infection and Asymptomatic Colonization by E. coli in the Urinary Bladder

Urinary tract infection (UTI) is an extremely common infectious disease. Uropathogenic Escherichia coli (UPEC) is the predominant etiological agent of UTI. Asymptomatic bacteriuric E. coli (ABEC) strains successfully colonize the urinary tract resulting in asymptomatic bacteriuria (ABU) and do not induce symptoms associated with UTI. Oxylipids are key signaling molecules involved in inflammation. Based on the distinct clinical outcomes of E. coli colonization, we hypothesized that UPEC triggers the production of predominantly proinflammatory oxylipids and ABEC leads to production of primarily anti-inflammatory or proresolving oxylipids in the urinary tract. We performed quantitative detection of 39 oxylipid mediators with proinflammatory, anti-inflammatory, and proresolving properties, during UTI and ABU caused by genetically distinct E. coli strains in the murine urinary bladder. Our results reveal that infection with UPEC causes an increased accumulation of proinflammatory oxylipids as early as 6 h postinoculation, compared to controls. To the contrary, ABEC colonization leads to decreased accumulation of proinflammatory oxylipids at the early time point compared to UPEC infection but does not affect the level of proresolving oxylipids. This report represents the first comprehensive investigation on the oxylipidome during benign ABEC colonization observed in ABU and acute inflammation triggered by UPEC leading to UTI.

Significance of Asymptomatic Bacteriuria

Since the recognition of asymptomatic bacteriuria (ABU), several studies have questioned its significance. It is a very common condition, observed in many healthy individuals. Current guidelines mandate that ABU should not be treated in all cases, as it does not seem to improve the outcome. Conditional restrictions for treatment of ABU can be relaxed in certain situations, with minimal exceptions to the rule.

Management of Asymptomatic Bacteriuria, Urinary Catheters and Symptomatic Urinary Tract Infections in Patients Undergoing Surgery for Joint Replacement: A Position Paper of the Expert Group 'Infection' of swissorthopaedics

In this position paper, we review definitions related to this subject and the corresponding literature. Our recommendations include the following statements. Asymptomatic bacteriuria, asymptomatic leukocyturia, urine discolouration, odd smell or positive nitrite sediments are not an indication for antimicrobial treatment. Antimicrobial treatment of asymptomatic bacteriuria does not prevent periprosthetic joint infection, but is associated with adverse events, costs and antibiotic resistance development. Urine analyses or urine cultures in asymptomatic patients undergoing orthopaedic implants should be avoided. Indwelling urinary catheters are the most frequent reason for healthcare-associated urinary tract infections and should be avoided or removed as soon as possible.

Microbiome in the urinary system-a review

Urine was considered sterile in healthy individuals for many years, and the presence of bacteria signified urinary tract infection. With the development of Expanded Quantitative Urine Culture (EQUC) and utilization of molecular techniques, the previous clinical dogma is no longer valid. Instead, healthy people harbor a considerable microbial community, or microbiota, in their urinary systems. Similar to other physiological niches where microbiota contribute to the health status of their hosts, recent studies demonstrated different microbial populations also play a crucial role in urinary health of individuals. Understanding urinary microbiome thus allows a more holistic approach in the diagnosis, treatment, and prevention of diseases and disorders in urinary system. This review article provides an overview of current findings in urinary microbiome and discusses some of the gaps for future research.

The female urinary microbiota, urinary health and common urinary disorders

This review provides the clinical context and updated information regarding the female urinary microbiota (FUM), a resident microbial community within the female bladder of many adult women. Microbial communities have variability and distinct characteristics in health, as well as during community disruption (dysbiosis). Information concerning characteristics of the FUM in health and disease is emerging. Sufficient data confirms that the microbes that compose the FUM are not contaminants and are cultivatable under appropriate conditions. Common clinical conditions, including urinary tract infection (UTI) and urgency urinary incontinence (UUI), a common form of urinary incontinence (UI), may be usefully reconsidered to determine the role of the FUM. Knowledge of FUM characteristics may help advance prevention, diagnosis and treatment of these conditions and other common lower urinary disorders in women. The FUM appears related to UTI and UUI in adult women. The specific role of the FUM remains to be clarified and requires significant additional work in describing FUM variability and resilience in health. Unique aspects of the FUM prompt re-evaluation of existing nomenclature to more appropriately define health and disease; the concept of dysbiosis may be useful for understanding the interaction of the FUM with other aspects of lower urinary tract physiology, including urothelial signaling. Clinicians, through their clinical laboratories, can adopt enhanced urine culture techniques that more fully describe the living microbes within the FUM. This additional information may provide clinicians and their patients an opportunity to impact clinical care without antibiotic use, if the FUM can be appropriately modified to improve treatment precision for UTI and UUI.

Increased Age, but Not Parity Predisposes to Higher Bacteriuria Burdens Due to Streptococcus Urinary Tract Infection and Influences Bladder Cytokine Responses, Which Develop Independent of Tissue Bacterial Loads

Streptococcus agalactiae causes urinary tract infection (UTI) in pregnant adults, non-pregnant adults, immune-compromised individuals and the elderly. The pathogenesis of S. agalactiae UTI in distinct patient populations is poorly understood. In this study, we used murine models of UTI incorporating young mice, aged and dam mice to show that uropathogenic S. agalactiae causes bacteriuria at significantly higher levels in aged mice compared to young mice and this occurs coincident with equivalent levels of bladder tissue colonisation at 24 h post-infection (p.i.). In addition, aged mice exhibited significantly higher bacteriuria burdens at 48 h compared to young mice, confirming a divergent pattern of bacterial colonization in the urinary tract of aged and young mice. Multiparous mice, in contrast, exhibited significantly lower urinary titres of S. agalactiae compared to age-matched nulliparous mice suggesting that parity enhances the ability of the host to control S. agalactiae bacteriuria. Additionally, we show that both age and parity alter the expression levels of several key regulatory and pro-inflammatory cytokines, which are known to be important the immune response to UTI, including Interleukin (IL)-1β, IL-12(p40), and Monocyte Chemoattractant Protein-1 (MCP-1). Finally, we demonstrate that other cytokines, including IL-17 are induced significantly in the S. agalactiae-infected bladder regardless of age and parity status. Collectively, these findings show that the host environment plays an important role in influencing the severity of S. agalactiae UTI; infection dynamics, particularly in the context of bacteriuria, depend on age and parity, which also affect the nature of innate immune responses to infection.