Use of Probiotics in Reducing Recurrence and Severity of Urinary Tract Infection

Chapter One

1.0 Introduction

Globally, Urinary tract infections (UTIs) are one of the most critical infections associated with up to 15-30% of hospitalizations for infectious and 6% of infection-related deaths (Redondo-Sánchez et al., 2021; Yang et al., (2022). Between 2019 and 1990, global cases of UTIs saw a 60% rise from 404.61 to 252.25 million (Zhu et al.2021) and a 50% increase in hospital admission (Redondo-Sánchez et al., 2021). This resulted in global deaths due to UTIs hitting 236,790 in 2019 (Yang et al., 2022). This phenomenon has resulted in significant financial burdens due to various treatment costs. According to Zilberberg et al. (2022), the disease burden of UTIs has increased significantly, culminating in an approximate financial burden of $45 billion in 2018, an increase from $2.8 billion in 2010.

While the incidences for both genders peak at 35, the UTI prevalence rate is 3.6 higher in men than women (Yang et al., 2022). Notably, the incidences of UTI stagnate and reduce after 35, and they start to pick up in the elderly generation. According to Medina & Castillo-Pino (2019), 23.3% of women in America and 6.8% of men suffer from UTI in a lifetime. Lifetime risk among adult women is between 50% and 60%, and the incidence rate rises with age (Medina & Castillo-Pino, 2019).

This dissertation aims to describe the process for ascertaining that the best information is found for Evidence-Based Practice (EBP) regarding the use of probiotics in preventing the recurrence and severity of UTI. This chapter presents an introduction to the subject, while the next chapter will describe the search through the literature. A critical appraisal of the selected articles follows, and the findings are afterward discussed. Recommendations for practice and conclusions, together with the strengths and limitations of the study, are in the final chapter.

1.1 Urinary Tract Infections (UTIs)

Urinary Tract Infections (UTIs) can occur in any section of the urinary system (Medina & Castillo-Pino, 2019). They mainly occur in the lower part, namely the bladder, and urethra, and are pharmacologically treated with antibiotics while the patient is advised to drink plenty of fluids. Bacteria are the most common etiologic agents in UTIs (Table 1.1), but fungi and viruses may play a role in some instances (Flores-Mireles et al., 2015).

Table 1.1

Most Prevalent Bacteria Causing UTI

Type of Bacteria Prevalence
Escherichia coli Most prevalent bacterium (Ribić et al., 2018).
Staphylococcus saprophyticus often isolated from younger females
Proteus mirabilis Less significant
Enterococcus faecalis Less significant
Pseudomonas aeruginosa Less significant
Klebsiella pneumoniae Less significant (Sheerin & Glover, 2019)

1.2 Pathophysiology and Risk factors

Bacteria enter the urinary system via the urethra and multiply in the bladder (Flores-Mireles et al., 2015). Uropathogens ability to colonize or be eradicated in the bladder is ultimately determined by the outcomes of intricate host-pathogen interactions (Flores-Mireles et al., 2015). Harmful uropathogens such as E. coli, a commensal in the human intestine, contaminate the urethra and bladder (Meštrović et al., 2020). Ribić et al. (2018) reported that uropathogenic bacteria are characterized by the expression of fimbrial adhesions, which the bacteria use to attach themselves to glycoproteins and glycolipids on the outside of the epithelial cell.

According to Ribic et al. (2018), these bacteria can undermine the urinary tract’s defense mechanism created by the urine flow to flush them away, thus continuing to thrive inside the urinary system. Bacteria create chemicals like hemolysin, toxins, and colony-necrotizing agents, which compromise the epithelium’s barrier function, facilitating invasion and thus raising the probability of infection (Ribic et al., 2018). Likewise, uropathogens may invade host epithelial cells, where they can multiply and serve as a reservoir for recurring infections (Ribić et al., 2018).

Women aged sixteen to sixty-four years are more susceptible to pathogen invasion in the urethra and bladder due to skin pH, hormonal changes, and body changes such as pregnancy (Flores-Mireles et al., 2015). Likewise, hormonal changes affect the infection rate; for instance, when women are nearing menopause, their estrogen level begins to decrease, causing the vaginal wall to get thinner, exposing it to infections (Calleja-Agius & Brincat, 2015). This could, in turn, contribute to infections in the adjacent lower urinary tract. Moreover, women have a shorter urethra than men; therefore, the bacteria have a shorter length to climb and affect the bladder (Bono et al., 2022). Skin sensitivity is also very high in women since the tissue lining the vagina is a thin mucosal lining, causing an increased sensitivity rate (Al-Badr & Al-Shaikh, 2013). Moreover, women have a shorter urethra than men, so bacteria have a shorter length to climb and affect the bladder (Bono et al., 2022). Skin sensitivity is also very high in women since the tissue lining the vagina is a thin mucosal lining, causing an increased sensitivity rate (Al-Badr & Al-Shaikh, 2013).

The most common causes of UTI in women include issues related to their physiology, sexual activity, age, menopause, and specific birth control methods (Storme et al., 2019). Other risks include anomalies in the urinary tract, an impaired immune system, the use of a urinary catheter, and a current operation on the urinary tract, pre- and post-coitus voiding habits, wiping style, wearing tight underwear, delayed voiding behaviors, and vaginal douching (Storme et al., 2019). Pregnancy, diabetes, and immunosuppression raise a woman’s risk of recurrent UTI because they make it easier for uropathogens to access and overcome the body’s normal defences (Storme et al., 2019).

1.3 Signs and Symptoms of UTI in Women

According to Schoor (2016), women can have complicated or uncomplicated UTIs. An uncomplicated UTI is the most common and develops when there are no structural or functional anomalies in the urinary system. The more complex kind develops when an anomaly in the urinary system raises a person’s risk of infection (Freire et al., 2020). Women with uncomplicated UTI do not consider it an illness that would make them stay away from work. This is because symptoms are few, including frequency of urine, dysuria, difficulties initiating urine flow, blood in urine, and rapid beginning of the urge to urinate (Bono & Reygaert, 2021). However, it must be quite a challenge to continue with one’s everyday activities while coping with some or all of the symptoms of a UTI (Table 1.2). It may also be a financial burden to continuously need antibiotic therapy while also suffering from the side effects of the treatment. Considering these women are often employees and homemakers, mothers of young children, or carers of older relatives, suffering from UTIs must cause extra stress. Finding a solution to UTIs would significantly improve the quality of life of these women and their families.

Table 1. 2.

Signs and Symptoms of UTIs in Women

Signs & symptoms of UTI Description
Dysuria Painful voiding
Regularity and perseverance of urination Voiding time is short.
Haematuria Presence of blood in the urine
Vaginal discharge UTI affects the composition of bacteria in the vagina, thus causing a discharge during infection.
Irritation Feeling a heat sensation in the bladder that causes pain
Abdominal pain Sharp, or dull pain felt in lower abdomen or pelvic region

1.4 UTI Treatment

1.4.1 Antibiotics

Notably, the first line of treatment is antibiotics. UTIs have traditionally been treated with various medications, including herbal enemas and narcotics (Nickel, 2005). Antibiotics are the empirical therapy of choice for UTIs (Bischoff et al., 2018). The standard course of treatment lasts for three days and typically results in recovery in 85–90% of women while shortening the duration of symptoms the patients feel (Karam et al., 2019). There is a range of antibiotic agents available for the treatment of UTIs . Currently, nitrofurantoin and trimethoprim are administered to patients receiving first-line care (Squadrito & Del Portal, 2019). Different antibiotic treatment regimens are advised, including ciprofloxacin, cephalexin, co-amoxiclav, trimethoprim for women who are not expectant, and cefalexin for expectant women (Karam et al., 2019).

The recurrence of UTI among women is currently also treated by antibiotics; however, health professionals prescribe these drugs based on the individual woman’s resistance level and other considerations (Al-Badr & Al-Shaikh, 2013). Antimicrobial medicines are recommended to the patient based on the urinary complaint, susceptibility of the microorganisms causing the urinary infection, and urine concentrations of uropathogens (Al-Badr & Al-Shaikh, 2013).

Considering the widespread occurrence of resistance in 15-20% of E. coli in numerous countries, including the US, Greece, Austria, Sweden, Portugal, and the UK, amoxicillin, ampicillin, and sulphonamides are no longer the medications of choice for empirical therapy (Kahlmeter & Poulsen, 2012). Bacteria sensitivity remains high whether one uses clavulanic or amoxicillin acid or nitrofurantoin; nevertheless, nitrofurantoin should be avoided in individuals with pyelonephritis due to its low concentrations in the blood and tissue (Al-Badr & Al-Shaikh, 2013). Individuals with renal insufficiency, as well as those with lactation or pregnancy status, age, primary or recurring infections, diabetes, liver illness, immunosuppression, dehydration, and mental health issues, or are hospitalized, may need dosage adjustments. Antibiotics like cephalosporin and penicillin are generally safe for use in pregnancy, while those like sulphonamides, trimethoprim, and fluoroquinolones must be avoided (Kahlmeter & Poulsen, 2012).

Important therapeutic techniques for preventing recurrent urinary tract infections (UTIs) include prophylactic antibiotic regimens, post-coital prophylaxis, continuous prophylaxis, and acute self-treatment (Al-Badr & Al-Shaikh, 2013). Those with less than two bouts of UTIs annually are advised to manage the condition themselves. However, patients with more than three episodes annually are often thought to benefit from continuous antibiotic prophylaxis, post-coital or low-dose prophylaxis (Al-Badr & Al-Shaikh, 2013).

1.4.2 antibiotic resistance

The widespread usage of antibiotics over the last several decades and for various conditions, including UTI, has contributed to the rise of bacteria resistant to these drugs and the subsequent occurrence of antibiotic resistance (O’Brien et al., 2017; Karam et al., 2019). Spaulding et al. (2018) stated that although antibiotics are still the preferred choice for treating UTIs, the development of multidrug-resistant bacteria and changes to the normal intestinal microbiota over time has made the development of new therapeutic approaches imperative. Amongst approaches, there are deemed non-antibiotic treatment options (Table 1.3) and the inclusion of probiotics in the diet, which has become increasingly considered for treating UTI infections. Probiotics are available as supplements in the form of capsules or pills and in various foods like kefir and yogurt.

Table 1. 3.

Non-Antibiotic Remedies of UTI

Non-Antibiotic Remedies Description
Proper hydration Proper hydration increases the formation of urine, which ultimately flushes out the harmful bacteria in the urinary tract (Gupta & Vergnaud, 2020).
Frequent Urination Frequent urination is advisable to help clear bacteria from the bladder and urethra (Gupta & Vergnaud, 2020).
Heat Heat can be applied using a heated water bottle on the abdominal section to ease pain and uneasiness (Gupta & Vergnaud, 2020) allowing nature to take its course in controlling the UTI.
Lactobacillus Probiotic Lactobacillus is a beneficial bacterium that grows around the genital area, thus preventing the existence of harmful bacteria such as E. coli (Gupta & Vergnaud, 2020).
Cranberry Juice The proanthocyanidins in cranberry juice have been shown to inhibit bacterial attachment to the lining of the urinary system, hence decreasing the likelihood of urinary tract infections (Kaspar & Khoo, 2013). It is a treatment for UTIs that is both natural and conventional (Kaspar & Khoo, 2013).

1.5 Probiotics

The term “probiotic” refers to living microorganisms that, when given to a host in sufficient quantities, can improve that host’s overall health (Amara & Shibl, 2015). There are many distinct strains and species of probiotics accessible, existing in a wide variety of formulations that are administered in various ways. According to Kiepś and Dembczyński (2022), foods and dietary supplements are potential sources of probiotics (in tablet, capsule, and powder forms). Probiotic food sources and supportive treatment products may either naturally include the bacteria or have them added at some point in production (Liska et al., 2018). The most often ingested probiotics are found in fermented dairy items like yogurt and buttermilk.

Probiotics work in the human body to offer benefits such as food digestion, producing valuable products, and maintaining the digestive system’s pH (Amara & Shibl, 2015). Probiotics also help eliminate harmful microbes, lactase production, infection control, and the production of antimicrobial compounds, thus interfering with microbial infections (Amara & Shibl, 2015). Probiotic organisms, such as Lactobacillus, may create a barrier that prevents pathogenic bacteria from ascending the urinary system, colonizing, and ultimately causing infection (Amara & Shibl, 2015).

1.6 Effectiveness of Probiotics in Recurrent UTI Treatment

Women who have had recurring, complex UTIs or have been taking antibiotics for an extended period may benefit from lactobacilli. According to Liska et al. (2018), probiotics used to avert and treat genitourinary problems should include Lactobacillus species due to their role in restoring healthy vaginal microbiota. The vaginal mucosa may become more acidic because some Lactobacillus species produce biosurfactants and hydrogen peroxide (Liska et al., 2018). Considering all these features, Lactobacillus may be perceived as a probiotic of choice for preventing and treating urogynaecology infections (Schwenger et al., 2015).

Studies have indicated that administering commensal bacteria in probiotics may decrease the number of pathogens present, resulting in a more stable microbiota (Hemarajata & Versalovic, 2012; Khan et al., 2019). Lactobacilli can inhibit uropathogenic bacteria from adhering, growing, and colonizing the female reproductive tract. Robust Lactobacillus species’ microbial communities have been found to have a substantial inhibitory impact on E. coli (Foxman, 2014). Another randomized research revealed that L. crispatus probiotic suppositories administered directly in the vagina might minimize the prevalence of recurrent UTIs (Stapleton et al., 2011).

Liska et al. (2018) indicated that probiotics are helpful when combined with other medications or as an alternative therapy to prevent recurring urogenital infections, even though there are few indications for use. According to Hooton et al. (2020), the absence of documented therapy guidelines for recurrent UTIs and the variety of levels of effects of the recommended treatments in different individuals lead to the conclusion that probiotics need to be explored and examined as part of multimodal treatments to be used in multifactorial conditions like recurrent UTIs

1.7 Relevance of Selected Topic

As McCann et al. (2020) noted, the financial burden of UTIs has been amplified by antibiotic resistance, which is considered the first line of treatment. According to WHO (2021), Antibiotic resistance is considered one of the ten global health issues. Because UTIs are 25% more prevalent than any other infection, antibiotic resistance poses more problems because of its high prevalence. According to Antimicrobial Resistance Collaborators (2022), 1.27 Million people died globally from Antibiotic resistance infections. In Europe, 67.7/100000 and 17.6/100000 people died from drug resistance and drug-resistant infections.

This is compounded by UTI’s tendency for recurrence in many patients, requiring repeated use of antibiotics. While 50–60% report at least one episode of UTI in their lifetime, 80% of RUTIs are reinfections (Al-Badr, A., & Al-Shaikh, G. (2013). According to Akgül & Karakan (2018), a 24% possibility of recurrence has been reported for women below 30%. This phenomenon has continued to pose a significant threat to public health that requires a sustainable non-antibiotic solution.

According to Yang et al. (2022), in addition to UTIs recurrence resulting in low quality of life due to numerous hospital visits and economic burden, numerous severe symptoms that include stress, septicemia, shock, and eventual death are evident. A study by Mehta et al. (2021) reports that silent suffering is becoming an everyday occurrence that needs to be borne without much complaint. Additionally, the annoying urge of frequency of urine, dysuria (Mehta et al., 2021), and the side effects of antibiotics, such as nausea and bloating (Mohsen et al., 2020) raised questions about whether Probiotics could be sustainable solutions that could be adopted to reduce the incidence of recurrent UTI in health contexts.

1.8 Evidence-Based Practice (EBP)

Scientific literature is voluminous, and many topics are researched from different aspects. Identifying the right studies to inform a topic and answer a specific research question is an endeavor that needs to be well thought out and thorough. EBP depends on rigorous research published, reviewed by experts, and disseminated among health professionals who can then make clinical decisions based on the evidence produced by the research.

The first step in the EBP process is to formulate a Research Question (RQ), and the second step is to search through the already published literature on the selected topic, followed by a critical appraisal of the selected articles to find out whether the research described is sound enough to base clinical decisions on it.

The research question guiding this study is: Are probiotics more effective in reducing the recurrence and severity of urinary tract infection (UTI) symptoms in women, compared to the exclusive use of regular antibiotics? The research question is crucial since it will guide the focus of the research in selecting relevant studies that will help in accurately answering the research question (Patino & Ferreira, 2016). Furthermore, the research question is essential since it will help find a practical approach to reducing the recurrence and severity of urinary tract infections.

1.9 PICO Question/Framework

The PICO framework is the most popular method for organizing clinical questions since it includes all the necessary components. PICO is an abbreviation for Population (P), Intervention (I), Control or comparison (C), and Outcome (O). According to Eriksen and Frandsen (2018), the use of PICO serves three purposes; it compels the person asking the question to focus on what the individual being questioned considers to be the single most significant problem and consequence; it makes the automated search stage easier by guiding the questioner toward the correct language and keywords and, it urges the person asking the question to clearly describe the issue, the intervention, and the results connected to the particular treatment delivered to a patient. Table 1.4 shows how the PICO framework was used to formulate a research question regarding the effectiveness of probiotics in minimizing the recurrence of UTIs.

Table 1.4.

PICO Framework for formulating the Research Question

Elements Definition
P Women with UTI
I Probiotics
C Exclusive antibiotics
O Reduced recurrence of UTI

1.10 Conclusion

This chapter gave a comprehensive overview of urinary tract infections, treatment, and prevention of recurrence and severity of these infections. The next chapter will outline the search strategy through the literature to identify and select studies on the selected topic.

Chapter Two: The Method

2.0 Introduction

Despite the availability numerous peer reviewed materials meant to inform provision of medical care, medical practitioners still fail to provide the necessary evidence-based practice (EBP) (Duff, et al., 2020). According Li, Cao & Zhu (2019), EBP stipulates the need to adopt the best scientific evidence for decision making critical in providing evidence-based care to patients. By using PRISMA framework, the current systematic research outlines the process used in identification of the best scientific research studies to answer the previously identified PICO question. Various steps that include databases research using organized keywords, eligibility criteria and the inclusion and exclusion criteria (Figure 1) will be expounded in this chapter. Studies that meet the PRISMA framework threshold will undergo a critical appraisal using the CASP tool for accuracy determination and internal validity.

2.1. Keywords and Synonyms

The initial step of searching through the literature is to identify which keywords to use in the search. Keywords are words typed in the search box for specific articles. The precision of the crucial terms produces better results since it allows one to analyse sources that are more directly related to the study. Keyword research is fundamental to identifying the most relevant articles to use in research (Bekhuis, 2015). Table 2.1. indicates the list of keywords incorporated in line with the formulated PICO question. Every keyword was associated to a PICO element to aid in finding the most relevant studies in the area of research. Synonyms of the keywords were also used in instances where the research collected did not use the exact keywords highlighted in the search strategy. Keywords facilitate the identification of specific articles (Bekhuis, 2015). Using the advanced search option, it is easy to find eligible words by using keywords. The synonyms or the alternative words were also attached to the PICO element, thus linking them to the keyword search. The synonym formulation was effective through using a synonym generator, thesaurus.

Table 2.1

Keywords and Synonyms Used

PICO Element Keywords Synonym
Patient Women with a medical history of UTI.
  • Adult women with UTI
  • Elderly women with UTI
  • Women above 65 years old with UTI
Intervention Probiotics
  • Lactic Acid
  • Lactobacillus
Comparison Antibiotics
  • Conventional medications
  • Carbapenems treatments
Outcome UTI recurrence UTI incidences and prevalence

2.2. Search Strategies and Databases Used

The current study depended on peer-reviewed materials from dependable databases at the University of Malta HyDI and Elton B. Stephens Company (EBSCO) platforms. Elton B. Stephens Company (EBSCO) is a platform source of multi-disciplinary academic and professional databases. It was selected for this research because its multi-disciplinary articles enable it to avail comprehensive, reliable data. The platform also has advanced search features allowing a person to customize their search precisely to the topic of choice (Lindberg, 2000). From these platforms, relevant articles published in the last ten years were retrieved from 4 databases: PUBMED, Cumulative Index to Nursing and Allied Health Literature (CINAHL), ProQuest, and MEDLINE. These databases were justifiable to their ability to contain relevant medical-based materials (Table 2.2).

Table 2.2: Databases description.

Database Justification
1 PUBMED PUBMED database specializes in availing information in the field of medicine. It avails a wide range of peer reviewed articles relating to different topics in medicine. It was selected for this research because the articles it avails are peer reviewed hence credible and relevant. The articles are comprehensive covering many medical topics that are evidence based hence credible (Lindberg, 2000).
2 Cumulative Index to Nursing and Allied Health Literature (CINAHL), Cumulative Index to Nursing and Allied Health Literature (CINAHL) database offers literature materials covering a wide range health topic such as nursing. These articles are comprehensive making it a reliable source of information touching on topics related to health and nursing. The website also uses modern search features that enables the researcher to easily access the topic of choice with precision. The articles are also credible because thy are availed by EBSCO which has a reputation of producing reliable sources of medical data (EBSCOHealth, 2020).
3 ProQuest ProQuest is a source of information on many areas of research such as medicine and nursing. The website was selected for this research because it offers a wide range and diverse source of information hence can be said to be comprehensive. In addition, the website’s data is multidisciplinary in nature. It can be relied on to research diverse topics from different perspective angles (Lindberg, 2000).
4 MEDLINE MEDLINE database avails literature materials covering different fields in health such as medicine and nursing. The website also uses advanced search feature. These features enable a researcher to access the exact articles of choice with ease. The articles in this website are also trustworthy and reliable as they are high quality academic and peer reviewed articles (Lindberg, 2000).

2.2. Search Tools Applied

The literature search was carried out in November 2022, and it was successful due to the combination of keywords and Boolean operators. Boolean operators are simple words such as AND, OR, and NOT combined with the keywords (Massachusetts Institute of Technology, [MIT] libraries, 2021). They expand or limit a search, thus widening the selection of articles (by using AND and OR) or focusing the search (by using NOT). The word AND was used whereby two or more keywords could unite, while OR was used so that the search would identify articles including either of the keywords. The word NOT was used in the inclusion or exclusion criteria to exclude research articles that contain a particular keyword but are irrelevant to the PICO element.

Another tool that was used in this electronic search was truncation. This term refers to a database search strategy in which the last letters of a term are replaced with several possible word endings and spellings to increase the scope of the search (Bramer et al., 2018). Truncations strengthen the search as it allows for many word variants to be searched for at once, thus yielding more relevant search results (Bramer et al., 2018).

Additionally, the Wildcard “?” was used to help increase the bandwidth of the research due to the diversity of the search terms used. Wildcards use the concept of truncation, but in this case, symbols replace a letter in the root word so that the search could identify all varieties of the word, whether they were written in English or American. A question mark, “?,” gets used when one character is being searched, whereas an asterisk, “*,” gets used during multiple-character searching (Kumar et al., 2010).

Ultimately, the search strategy using the identified search tools, including truncation and Wildcard, resulted in 1660 hits from the targeted databases.

Table 2.3. Search Strategy hits

Database Keyword Combination Limiters Field Searched Changes Implemented Hits Relevant articles
EBSCO women OR woman OR female?) AND (probiotics OR “lactic acid” OR Lactobacillus) AND antibiotics AND (UTI OR “Urinary Tract Infection”) Published in the last ten years


Published in English

Full texts Keywords 855 4
Cumulative Index to Nursing and Allied Health Literature (CINAHL), women OR woman OR female?) AND (probiotics OR “lactic acid” OR Lactobacillus) Published in the last ten years,

British English Language

Full texts, Abstracts, Journal articles Database, keywords 334 3
PubMed women OR woman OR female?) AND (probiotics OR “lactic acid” OR Lactobacillus) AND antibiotics AND (UTI OR “Urinary Tract Infection”) Peer-reviewed,

Published in the last ten years,

English language

Free full articles, PDFs, Abstract, academic journals Fields searched, keywords 368 5
ProQuest probiotics AND antibiotics simultaneously (women OR woman OR female?) AND (probiotics OR “lactic acid” OR Lactobacillus OR antibiotics) Published in the last ten years,

English language,


Journal article

Full text Limiters, Databases 14 1
MEDLINE (Probiotics OR “lactic acid” OR Lactobacillus OR antibiotics) AND (UTI OR “Urinary Tract Infection”) Worldwide, peer-reviewed, Published in the last ten years Keywords, fields searched 89 2

2.4 Limiters

As indicated in Prisma, the need to check for article eligibility requires the utilization of various limiters. According to Gusenbauer & Haddaway (2020) and Havill et al. (2014), limiters are essential in research because they focus on the most relevant information the source database provides. Limiters help narrow down research, especially when a database has too many hits (Gusenbauer & Haddaway, 2020). Table 2.4. shows the limiters set on the databases in this study and the rationale for applying each.

Table 2.4.

Limiters and Rationale for their Use in Electronic Searches

Limiter Description Explanation
Full texts The search gets filtered to only sources that are full texts.

Rationale: Full texts can be appraised in detail to identify evidence regarding the topic under study (Tod et al., 2022).

The full-text limiter was set to ensure the sources picked allowed full access to the article from the abstract to the conclusion and references. The limiter ensures that the articles included in the review do not only contain abstracts and short summaries (EBSCO, 2018). The limiter was used to eliminate any article relevant to the PICO question but lacking full access, thus limiting the amount of information used in the research.
Peer Reviewed The hit results get filtered to those that are either peer-reviewed or referenced journals.

Rationale: Peer reviewed articles are more trustworthy as they would have been reviewed by experts in the field (Kelly et al., 2014).

Peer-reviewed results, academic journals, and complete texts, and the publication date range which was set to 2012-2022. Peer-reviewed articles were considered to ensure that all selected articles were high quality since other professionals had already reviewed them.
Journal/Magazine Only the sources with the name field journal or magazine get picked from the database.

Rationale: Field journals are more likely to be accurate and up to date in the findings reported (Cooper et al., 2018).

The credibility of the sources was integral, thus the need to consider academic journals.
Date of Publication A specified date range is used to search for sources from the database.

Rationale: Since this is a search for evidence on which to base practice, evidence found needs to be the latest available (Cooper et al., 2018).

The publication date was ten years, that is, between 2012-2022. It ensures the sources presented the most current studies about the usage of probiotics in reducing the recurrence and severity of UTIs. When using the online database, the date when the source was first published is always considered; however, if there is an update on the same source, it is essential to use the most current sources. Up-to-date sources will ensure that the recommendations made on the research topic are relevant and practical
Population The type of sample group the research focuses on, in this case, women.

Rationale: Identified studies need to be specific to the population on which practice is to be administered (Aslam & Emmanuel, 2010).

The population was an essential consideration for the limiters since the research focused on how women were affected by UTIs and the potential remedies for them. The sample population is significant in any research since it provides a base for answering the PICO question (Aslam & Emmanuel, 2010). Findings need to be applicable to a definite population for safe evidence-based clinical decisions. Therefore, research that did not have women as the primary population was omitted

2.5 Inclusion and Exclusion Criteria

The inclusion and exclusion criteria are essential for identifying the research that fits the population under investigation. The criteria help to filter the obtained sources further and ensure the research picked is relevant to the research question. Table 2.4 demonstrates the inclusion and exclusion criteria applied in the research on using probiotics as a preventative measure for UTIs.

Table 2.4.

Inclusion and Exclusion criteria

Criteria Inclusion Exclusion Rationale
Population women with UTI Men with and without UTI, Women who do not have UTI. Men have a different anatomical and physiological makeup and would confound the findings (Ngun et al., 2011).

Women who do not have UTI do not need any treatment.

Intervention Women with UTI on Probiotic
  • Women and men with UTI on antibiotic
  • Women and men with UTI on other antibiotic alternatives rather than probiotic
  • Women with UTI on antibiotic
Studies that don’t examine UTI antibiotic efficacy
Outcome Reduced/prevention of UTI recurrence Studies that do not report UTI recurrence The outcome of interest refers to women with recurrent UTIs (Medina & Castillo-Pino, 2019).
Studies Systematic reviews, (SR) Randomized Controlled Trials (RCTs), case studies, self-reporting, mixed method, observational study Newspaper, editorial, opinions and blog articles The excluded publications are not in the highest levels in the hierarchy of evidence and may therefore lead to erroneous decisions on practice (Petrisor & Bhandari, 2007).
Date Last ten years Beyond ten years. Evidence to be used as a basis for practice needs to be up-to-date (Madsen et al., 2016).

2.6 The Selection Process

The total hit results on the electronic search were 1660, and 25 results on the manual search process. The PRISMA (Moher et al., 2009) was used as a reporting item. The selected articles’ topics were read to determine the sources’ eligibility for the study. The abstract of each potentially relevant study was also read to establish the source’s relevance. Figure 2.1 demonstrates the selection of the articles through PRISMA (2009). The outcome of the search includes four studies of which three were randomized control trials, and one was an SR&MT (Table 2.5).

Figure 1. PRISMA Flow Diagram Generator (Adapted from Moher et al., 2009)

Table 2.5.

Types of Sources Selected and Number

Type of Sources Number
Randomized Control Trials 3
Systematic Review and meta-analysis 1


2.7 Critical Appraisal

Critical Appraisal is the process of carefully and systematically examining the resources to help evaluate the sources’ efficiency and accuracy (Mhaskar et al., 2009). Though several research appraisal tools include the Critical Appraisal Skills Programme tool (CASP), Jadad scale, Pedro Scale, and the JBI Critical appraisal tool, to assist in research appraisal, adopting only one tool is critical for uniformity of results. Ultimately, CASP was decided as the tool of choice because it was deemed to be more friendly and straightforward to use. The Cochrane Qualitative and Implementation Methods Group also endorses the CASP tool as the most popular instrument for quality evaluation in health-related qualitative and quantitative data syntheses (Long et al., 2020). The CASP tools for both the SR (Appendix A) and RCTs (Appendix B) were used in assessing the strengths and weaknesses of the research approaches used in the selected articles to ensure they met the research criteria.

2.8. Conclusion

The chapter has described the search strategy of the sources included in the study and the outcome of this search, namely, an SR and 3 RCTs. It also highlighted the search for and selection of an appropriate critical appraisal tool. The next chapter appraises the four peer-reviewed materials following the PRISMA framework for accuracy and intel validity using the CASP tool.

Chapter Three: Critical Appraisal

3.0 Introduction

The field of Health Science regularly produces a lot of research published to assist healthcare professionals when making decisions on managing healthcare issues. These decisions need to be taken on sound and up-to-date research if there is to be Evidence-Based Practice. In health care, EBP entails using the latest scientific evidence applied after review, analysis, and translation of research (Li et al., 2019). EBP aims to ensure that the methods used in patient management are based on verified facts, not to harm, promote positive outcomes and prevent complications (Roetzel, 2019). For this reason, critical appraisal in research is important as it aims to determine whether the studies meet the research intention in relevance and value in context (Morrison, 2017). Critical appraisal makes it possible to determine whether research is applicable depending on how well it answers the set research questions. More specifically, critical appraisal enables healthcare professionals to minimize the amount of data to process by removing any unreliable or unnecessary research, finding the most relevant articles, separating what can be proven from what can only be assumed, misquoted, or believed, and evaluate the study’s reliability, therapeutic relevance, and application, and identify any sources of bias (Morrison, 2017). An in-depth appraisal is even more crucial if the literature is to be used for making evidence-based decisions for EBP implementation (Hanson et al., 2019).

This chapter critically assesses the articles used in this research and the hierarchy of evidence. Key studies’ quality will also be assessed. Lastly, the ethical considerations associated with the research will be covered.

3.1 Hierarchy of Evidence

The hierarchy of evidence (Fig 2) provides a way to organize research studies according to their quality and reliability based on the rigor of their design and the level of control over potential biases. The higher the hierarchy of a study, the more reliable it is for making scientific decisions (Centre for Evidence-Based Medicine, 2009). The hierarchy of evidence places SRs and meta-analyses at the top. These studies combine and analyze data from multiple studies on a particular topic, using strict criteria for study selection and data analysis (Higgins & Green, 2011). They are considered the most reliable evidence because they provide the highest level of synthesis and rigor (Higgins & Green, 2011). Next are the Randomized Controlled Trials (RCTs), whereby participants are assigned randomly to receive either a treatment or a placebo (or alternative treatment). Then, the researcher compares the outcomes between the two groups. RCTs are considered the ideal standard for assessing the efficacy of interventions because they are designed to minimize biases and control for confounding factors (Hariton & Locascio, 2018).

Cohort studies are situated at the third level in the hierarchy. They follow a group of people over time, comparing those who are exposed to a particular factor (such as a risk factor or an intervention) to those who are not. Cohort studies can provide strong evidence of causation but are more susceptible to biases and confounding factors than RCTs (Centre for Evidence-Based Medicine, 2009). Next are the case-control studies that compare people with a particular outcome (such as a disease) to a group of people without the outcome, looking back in time to identify potential risk factors. Case-control studies help identify potential risk factors but are also more susceptible to biases and confounding factors than cohort studies (Centre for Evidence-Based Medicine, 2009). Cross-sectional studies are at the next lower level. These studies measure the prevalence of a particular outcome (such as a disease) and potential risk factors at a single time. Cross-sectional studies help generate hypotheses but cannot establish causality or control for confounding factors (Centre for Evidence-Based Medicine, 2009). Last in the hierarchy are case reports and case series. They are helpful in generating hypotheses but cannot establish causality or control for confounding factors (Song & Chung, 2010). Thus, each level of evidence indicates more reliability for scientific decisions because studies higher up in the hierarchy are generally better designed, better controlled, and less susceptible to biases and confounding factors. Ultimately, it is possible to provide the level of evidence for each of the included articles.

(Table 3.3)

Evidence Based Practice - Subject - Health - Library at Torrens

Figure 2.

Hierarchy of Evidence Source: (National Health and Medical Research Council, 2009)

3.2 The Critical Appraisal Method

The Critical Appraisal Skills Program (CASP) guide was used to appraise the studies in this section. Table 3.1 shows the selected studies grouped according to the research methodology design. CASP tools are a set of checklists that researchers use to evaluate the quality of research studies. The tools are designed to help researchers critically appraise the evidence base and determine whether the studies they are examining are of high quality and can be trusted (Long et al., 2020). The CASP tools cover different research designs, including RCTs, observational studies, qualitative research, diagnostic studies, and SRs. Each tool contains a series of questions that can be used to systematically assess the quality of the study, such as the validity and reliability of the study design, the sampling strategy, the data collection and methods used in the analysis, and the interpretation of the findings (Long et al., 2020).

The selected studies for this dissertation were first read through and then appraised using their respective CASP tools; The SSR checklist ( Appendix A) and the RCT checklist ( Appendix B). In the appraisal process, each question was examined, and the study was evaluated against the criteria specified. This allowed for identifying potential biases, confounders, and sources of error and determining whether the results were robust and generalizable. After applying the CASP tools, included were ranked according to their quality and level of evidence. The chosen studies included three RCTs and one SR (Table 3.1), which ranked high on the hierarchy of evidence and scored highly on the CASP tools.

As previously noted, SRs, grouped with meta-analysis at the top of the hierarchy, are reliable and high-quality sources. Well-conducted SRs, either with or without an incorporated meta-analysis, often provide the strongest evidence since they are derived from the findings of several studies uncovered by a detailed, systematic search of literature and selection (Davidson & Iles, 2013). Due to the methodology used in these studies, the possibility of an effect of bias is minimized, increasing the reliability (Higgins & Green, 2011).

RCTs are accorded the second highest level since they are intended to be objective and include a lower probability of systematic mistakes. This is because randomization may reduce disparities in features of the groups that may affect the result, yielding the most conclusive data about the effect of the intervention or exposure on the outcome (Zabor et al., 2020).

3.3. Appraisal of the General Sections

This section provides a detailed appraisal of the general sections that include titles, abstracts, authors, keywords, and relevance to study area (Table 3.2)

Table 3.2 presents an appraisal of the titles, abstracts, authors, keywords and relevance of the selected study to the present study.


Title The titles of all the selected articles were clear and concise and they presented clarity in the main issue being discussed in them. The words used in phrasing the article title made it easy to identify the quality and relevance of the title used. Having a good title is important for research as it can increase the visibility and impact of the study, attract readers’ attention, accurately reflect the content of the study, and help researchers identify relevant articles for their own research (Jamali & Nikzad, 2011; Gunnarsdottir & Leydesdorff, 2012).
Abstract All the included articles had a clear and concise abstract that clearly presented the main goal, methods, findings and conclusions of the study. The abstracts were very critical towards the understanding the overview of the article thus making it easy to analyse the quality of the entire article. This is because they provide information about the purpose, methods, results, and conclusions of a study, allowing readers to quickly evaluate the relevance and quality of the research (Hartley & Betts, 2018).
Authors All the articles acknowledged the names of the authors and detailed their attributes. The full names of the authors were also presented thus acknowledging the efforts that went into developing the arguments of the articles. Additional, included articles provided credentials of the authors thus making it easy to track the credibility of the information presented in the article. The credentials of an author can help readers determine their level of expertise and knowledge on the subject matter, which can influence how much trust readers place in the information presented (Kim et al., 2018).
Keywords All the articles selected, highlighted the main keywords used in the research thus making it easy to include them or exclude them in the research. Including relevant keywords in research is important as it helps readers to quickly identify whether the study is relevant to their research interests, and ensuring that the study is properly indexed and catalogued in online databases and repositories (Losee & Gupta, 2012).
Relevance to study area The main strength of the articles used was the relevance to the field of study. The words used on the title were very clear in representing the study area of focus.

3.3 Overview of selected studies

3.3.1 Overview of Systematic Review

In an SR, large volumes of information are objectively summarized, revealing gaps in medical research and highlighting helpful or hazardous actions that will be helpful for doctors, researchers, and even the general public (Gopalakrishnan & Ganeshkumar, 2013). However, while they are reliable scientific study methods, mistakes may occur. They may be deceiving or even destructive if the evidence is improperly handled or if they are skewed. Moreover, using a meta-analysis in an sSR enables a researcher to pool data from multiple studies and increase the statistical power of the analysis to provide more precise estimates of treatment effects, increasing the study’s strength (Lee, 2019). However, it is important to note that meta-analysis also has its limitations and potential sources of bias, such as publication bias, selection bias, and heterogeneity across studies (Lee, 2019). As such, a researcher should carefully consider the quality and characteristics of the underlying studies and interpret the study’s results in the context of the overall evidence base.

3.3.2 Overview of Meta-Analysis

3.3.3 Overview Randomised Controlled Trials

According to Hariton and Locascio (2018), an RCT divides participants into two major groups; the experimental and the control group (Hariton & Locascio, 2018). The control group receives the placebo while the experimental group receives the new intervention, after which data is compared on the effects of the intervention on the two groups (Hariton & Locascio, 2018). RCT findings indicate whether the intervention causes the effect since both groups have similar characteristics, the only significant difference being the intervention (Bhide et al., 2018).

Randomized control studies have an advantage over other studies in reducing the tendency to establish bias since the participants are randomly assigned to various groups (Bhide et al., 2018). The use of blinding and double blinding in RCTs helps to reduce the risk of bias and ensure the validity of the study results. Blinding refers to keeping the study participants, healthcare providers, outcome assessors, or data analysts unaware of the treatment assignment (Penic et al., 2020). Double blinding is a specific type that involves keeping the study participants and the healthcare providers or outcome assessors unaware of the treatment assignment (Penic et al., 2020). This is often achieved through placebo treatments or identical-looking interventions that do not contain the active ingredient. This methodology also reduces the chances of recall bias since the results included are objective and visible at the time compared to the retrospective study designs (Bhide et al., 2018).

However, RCT studies are expensive and time-consuming and may take a long before conclusion. If there is a small number of participants, there are increased chances of predictability and selection bias, reducing the method’s effectiveness (Gelman, 2018). There is also the risk that some effects of the intervention (negative or positive) are not detected in small numbers.

3.4 Characteristics of included studies

Table 3.1 provides a detailed characteristics overview of the 4 included articles with their corresponding hierarchy evidence level

Table 3.1.

Characteristics of the Key Studies

Study Design Author’s names and publication dates Title Sample size Key population characteristics Geographical site/publications included Methods Level of Evidence

& meta- analysis

Abdullatif, V. A., Sur, R., Eshaghian, E., Gaura, K., Goldman, B., Panchatsharam, P. K., & Gaura, K. A. (2021) Efficacy of Probiotics as Prophylaxis for Urinary Tract Infections in Premenopausal Women: A SR and Meta-Analysis 3 studies with an overall of

284 participants

Premenopausal women with a history of one or more UTI. Literature published between 2001-2021 Reviewed data in three studies conducted through randomized control studies. Level 1
Randomized control trial Heidari, F., Abbaszadeh, S., & Mirak, S. E. M. (2021) Evaluation Effect of Combination Probiotics and Antibiotics in the Prevention of Recurrent Urinary Tract Infection (UTI) in Women 162 patients Patients with a history of UTI from April 2015 April 2016 Baquyatalla urology department,


Patients were issued with 500 mg probiotics and antibiotics every day for 6 months Level 4
Randomized control study Koradia, P., Kapadia, S., Trivedi, Y., Chanchu, G., & Harper, A. (2019). Probiotic And Cranberry Supplementation for Preventing Recurrent Uncomplicated Urinary Tract Infections in Premenopausal Women: A Controlled Pilot Study. 90 participants Female patients between the ages of 18 and 55 who had had two or more episodes of an acute, uncomplicated urinary tract infection during the previous six months or within the previous year India BKProCyan or placebo was administered twice a day for 26 weeks Level 4
meta-analysis Grin, P.M. Kowalewska, P.M. Alhazzan, W. and Fox-Robichaud A, E. (2013). Lactobacillus for preventing recurrent urinary tract infections in women: meta-analysis 294 patients

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