Prevalence and antimicrobial sensitivity pattern of bacteria causing urinary tract infection: A comparative study between men and women

Prepared by the researcher  : Israa Ali Abboudi , Faculty of Science – University of Kufa

Democratic Arab Center

Journal of Afro-Asian Studies : Fifteenth Issue – November 2022

A Periodical International Journal published by the “Democratic Arab Center” Germany – Berlin.

https://democraticac.de/wp-content/uploads/2022/10/Journal-of-Afro-Asian-Studies-Fifteenth-Issue-%E2%80%93-November-2022.pdf

Abstract

Urinary Tract Infections (UTI) are one of the most common bacterial infections in routine clinical practice. It is also the most common nosocomial infection in many hospitals. Study of causative agents and their Antimicrobial sensitivity pattern are important factors helping formulating antibiotic policy. Generally, the most common uropathogen is Escherichia coli. Tertiary care hospitals, catering for already partially treated or maltreated patients as major chunk, may have different etiological agents and sensitivity pattern. Objectives: To study prevalence of pathogens causing UTI among patients .Urinary tract infections (UTIs) are among the most common bacterial infections in humans, accounting for 3.5 billion in health care expenditures yearly in the United States alone. Yet, treatments for UTI have seen little innovation over the past decade. As demonstrated in other body sites, such as the vagina and gastrointestinal (GI) tract, acute and infectious diseases often have indirect microbial contributions which serve as intriguing new targets for therapies. The recent discovery of the existence of a resident community of bacteria (i.e., microbiota) in the bladders of both women and men represents a novel avenue for targeting UTIs. However, before targeted approaches aimed at modulating the urinary microbiota can be thoroughly investigated, it is first necessary to understand the normal modulations of these bacteria in the context of the host. Temporal dynamics in the vaginal and GI microbiota have been well described, and often linked to lifestyle factors or behaviors. Rigorous, longitudinal studies are required to study these trends. To date, few studies have assessed the urinary microbiota in such a manner none were comprehensive, and all were in the context of lower urinary tract symptoms. This is primarily due to the impracticality of collecting repeated transurethral catheterized urine specimens for analysis. Therefore, through our study, we compared the most common bacteria that cause this infection to both women and me.            We obtained a set of conclusions        that resulted in several recommendations

Introduction

Urinary Tract Infection (UTIs) are one of the most common bacterial infection in routine clinical practice, clinical presentation of which ranging from asymptomatic to severe sepsis. UTI is one of the most important causes of morbidity in general population, and is the second most important cause of hospital visits. It also contributes as the most common nosocomial infection in many hospitals and accounts for approximately 35% of all hospital-acquired infections.3 this burden causes serious impact on the socioeconomic life of individuals and leads to a large proportion of antibacterial drug consumption.) 1) Generally, the predominant uropathogens for UTIs are gram-negative bacteria and Escherichia coli accounting for the highest prevalence in most instances. Other commonly involved urinary pathogens are Klebsiella spp., Proteus spp., Staphylococcus aureus, Enterobacter spp., Citrobacter spp., Pseudomonas aeruginosa, Acinetobacter spp., Enterococcus spp., and Candida albicans. UTI is treated with broad-spectrum antibiotics empirically to start with, which are de-escalated to specific antibiotic based on information obtained from the antimicrobial susceptibility pattern of the urinary pathogens. Widespread use of antimicrobial agents has led to the emergence of antibiotic resistant pathogens; also there is increase demand for new drugs. Distribution of uropathogens and their antimicrobial sensitivity patterns may differ regionally so it becomes necessary to study these and compile their data in particular settings. Sensitivity patterns,(2) from our hospital. Uttar Pradesh. Bacteria and archaea evolved about 3 billion years ago and have since adapted to every conceivable niche on Earth, including the human body. Much as the soil of a tropical rainforest harbors a unique but specific community of microorganisms, so do our bodies. These microorganisms are highly adapted to each of our organs and provide us with a range of vital functions that have yet to be fully appreciated or understood. Considering that, these microorganisms are equal in number to our somatic cells, the extent

 Their influence is seemingly infinite. The microorganisms that colonize our bodies are collectively known as the human microbiota. These microbes, which include bacteria, bacteriophage, fungi, protozoa, and viruses, when defined by their genomes, are referred to as the human microbiome. From a medical perspective, microbes have traditionally been associated with disease and, as such, our primary focus has been on eliminating and preventing their colonization of the human body. The Human Microbiome Project (HMP) represents the first major shift from studying microbes in relation to disease to exploring them in the context of health. The HMP used culture-independent methods to characterize the populations of microorganisms that naturally colonize humans (i.e., not in the context of disease).: the gastrointestinal (GI) tract, oral cavity,(3) vaginal/urogenital tract, skin, and nasal cavity. Besides providing an in-depth comprehensive description of the microbiome at each body niche, the project generated two important conclusions. The first was that, although the diversity and abundance of microbes varied dramatically, each body niche sampled showed a level of specificity that was consistent within and between subjects. This means that the microbiome of a particular body niche is more similar amongst people than it is amongst other body niches. The second conclusion was that the human microbiome has a degree of plasticity; the abundance and diversity of microorganisms within a person is not constant. Recent research shows that this plasticity is largely determined by our lifestyle choices and behaviors (1)

Vibrio species are bacteria that inhabit a wide variety of marine and aquatic environments. They usually cause gastroenteritis and extraintestinal infections in human beings. Among them is Vibrio cholerae that has more than 200 serogroups. Only two of these serogroups have epidemic potential: Serogroup O1 and serogroup O139. All other serogroups are together known as “Non- O1 and non O-139 V. cholera”.(4)

 Since the year 2000, around 40 cases of non-O1 and non-O139 infections have been reported to the Center for Disease Control (CDC) yearly. These infections mostly occur in late summer or early fall when the water is the warmest.(5)

Vibrio albensis, also known as “non-O1 serovar Vibrio cholerae” was studied by Shewan and Véron in 1974, it is a luminescent organism that biochemically resembles V. cholerae [4]. Despite the fact that V. cholerae non-O1 and non O-139 human infections are regularly reported [2], the literature about infections due to V. albensis remains relatively scarce. To the best of our knowledge the current case report is the first to label V. albensis as a cause of urinary tract infection in an immunocompetent male patient2

abdominal pain, nausea, vomiting, and decreased oral intake. He also reported chills and dysuria. The patient denied respiratory symptoms and change in bowel habits. In the ED, the patient was afebrile with stable vital signs. His physical exam was unremark- able except for mild lower abdominal tenderness.(6)

On presentation, blood was drawn for laboratory tests, and urine was sent for analysis and culture. During his stay in the ED, the patient received 1 L of normal saline intravenously, hyoscine (Scopinal) and metoclopramide (Primperan) to relieve his symp- toms.

The complete blood count showed leukocytosis with a white blood cell (WBC) count of 18,100 cells/mm3 (89% neutrophils). The urine analysis was significant for the presence of numerous WBCs, 10–15 red blood cells per high power field, and positive leukocyte esterase (500/µL). Other laboratory tests including electrolytes and creatinine were within normal.(7)

Considering a urinary tract infection high on the differential diagnosis, the ED physician discharged the patient on Ciprofloxacin 500 mg twice daily for a week empirically, while the result of the urine culture was still pending.

In 24 h, the urine culture on cysteine lactose electrolyte deficient (CLED) medium grew V. albensis 100,000 organisms/mL as identi- fied by Matrix-Assisted Laser Desorption/Ionization Time of Flight (MALDI-TOF) system (Bruker Daltonik, GmbH, Bremen, Germany) with a score of 1.85 (yellow flag).

Testing for antimicrobial susceptibility of this pathogen was done based on the CDC recommendation for V. cholerae, which included testing for: chloramphenicol, ampicillin, trimethoprim- sulfamethoxazole, tetracycline and nalidixic acid. In addition, disk diffusion was performed with a battery of antimicrobials used for Enterobacteriaceae, and interpreted according to the Clinical and Laboratory Standards Institute (CLSI) guidelines, which showed(8)

Correlations with Health and Disease

A comprehensive analysis of the urinary microbiota of TUC specimens in healthy women of varying demographics has yet to be published. However, several studies used small cohorts of healthy women as controls for comparison to particular disease populations. I compiled EQUC and S rRNA gene sequencing data on TUC urine specimens from 224 healthy female patients and compared the data across demographics and clinical variables. These patients were

recruited from various studies performed at Loyola University Chicago from 2013- 2018. In summation, I found that the urinary microbiota profiles are highly stratified by dominant taxa. For these participants, I determined the urotype (classified by a genus with >50% relative abundance; if no genus has ≤50% relative abundance, the specimen is designated as ‘mixed’) and found that women with a Gardnerella

urotype were likely to be younger, have a higher body mass index (BMI), and a low median vaginal parity score (i.e., number of vaginal deliveries). Women with an Escherichia urotype were likely to be older and post-menopausal, and unlikely to engage in vaginal intercourse. (5)

Correlations between the female urinary microbiota and various lower urinary tract diseases and disorders have been described, including: urinary incontinence (UI), interstitial cystitis/painful bladder syndrome (IC/PBS), UTI and UTI symptoms, overactive bladder (OAB), and neuropathic bladder. These are described below. UI is described in more detail in Appendix B, where I correlate symptom severity, as defined by urinary distress inventory (UDI) questionnaire scores, to the urinary microbiota and microbiome using EQUC sequencing. Some evidence exists showing a positive or beneficial role for the urinary microbiota. For example, in patients undergoing pelvic organ prolapse and urinary incontinence (POP-UI) surgery, Thomas-White et al. and Fok et al. found that 32% of women whose day of surgery TUC urine specimens had bacteria detected by SUC developed a post- operative UTI. By 16S rRNA gene sequencing, these specimens were dominated by the family Enterobacteriaceae (which includes the species E. coli). By contrast, in those who did not have SUC-detectable bacteria on the day of surgery, only 4% developed a post-operative UTI; by 16S rRNA gene sequencing, these latter specimens were dominated primarily by Lactobacillus. Furthermore, Thomas-White et al. found that in this same patient population, UTI risk was associated with a depletion of Lactobacillus iners specifically.(9) These data suggest that some populations of urinary microorganisms may predispose the bladder to infection, while others may be beneficial or protective. Urinary tract infections (UTI) represent serious threats to human health all around the world affecting millions of people each year. These are the most common nosocomial as well as community acquired

infections, resulting in high morbidity and increased economic loss in terms of treatment. UTIs are widespread in both males and females; nevertheless, females are more susceptible than males. In early childhood, persistent urinary tract infections may usually emerge and 1 to 8% of children may experience UTI at least once between the age of 1 and 11 years. Gram negative bacilli are the most prevalent uropathogens including Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Proteus mirabilis that result in bacteremia and hospital acquired infections (Sarwar et al., 2013). Etiologic agents of UTI are variable and usually depend on time, geographical locationand age of patients. However, Enterobacteriacea species including Escherichia coli, Proteus mirabilis, Enterobacter agglomerans, Citrobacter freundii and Klebsiella pneumoniae account for over 70% cases (Rasoul et al., 2009). Urinary tract infection (UTI) is the most common acute infection which occurs in females. Females are more frequently affected by UTI (particularly cystitis) due.(10)

A urinary tract infection, or UTI, is an infection of the urinary tract. The infection can occur at different points in the urinary tract. An infection in the bladder is also called cystitis or a bladder infection. An infection of one or both kidneys is called pyelonephritis or a kidney infection. The tubes that take urine from each kidney to the bladder are only rarely the site of infection. An infection of the tube that empties urine from the bladder to the outside is called urethritis. Urinary tract infections are the most common infections in clinical practice. (1) Urinary tract infection (UTI) is one of the most important causes of morbidity in the general population, and is the second most common cause of hospital visits. (2) Uncomplicated UTIs typically occur in the healthy adult non-pregnant woman, while complicated UTIs (cUTIs) may occur in all sexes and age groups and are frequently associated with either structural or functional urinary tract abnormalities. Examples include foreign bodies

such as calculi (stones), indwelling catheters or other drainage devices, obstruction, immunosuppression, renal failure, renal transplantation and pregnancy. (3) UTIs is described as a bacteriuria with urinary symptoms (4). The lower UTI infection is characterized by symptoms such as dysuria, frequency, urgency, and suprapubic tenderness. (5). UTI is more common in females than in males as female urethra structurally found less effective for preventing the bacterial entry (6). It may be due to the proximity of the genita(11). Urinary tract infections (UTIs) are the inflammatory disorders of the urinary tract caused by the abnormal growth of pathogens.

Urinary tract infection is known to cause short-term morbidity in terms of fever, dysuria, and lower abdominal pain (LAP) and may result in permanent scarring of the kidney. Urinary tract infections can be community acquired or nosocomial. Community-acquired urinary tract infections (CA-UTIs) are defined as the infection of the urinary system that takes place in one’s life in the community setting or in the hospital environment with less than 48 hours of admission. Community-acquired UTI is the second most commonly encountered microbial infection in the community setting. Nosocomial urinary tract infections (N-UTIs) are the infection of the urinary tract that occurs after 48 hours of hospital admission, and the patient was not incubating at the time of admission or within 3 days after discharge. Urinary tract infections may be asymptomatic,(12) acute, chronic, and complicated or uncomplicated, and the clinical manifestations of UTIs depend on the portion of the urinary tract involved, the etiologic organisms, the severity of the infection, and the patient’s ability to mount an immune response to it. Both asymptomatic and symptomatic UTIs pose a serious threat to public health care, hence reducing the quality of life and resulting into work absenteeism.

 The symptoms of UTIs such as fever, burning sensations while urinating, LAP, itching, formation of blisters and ulcers in the genital area, genital and suprapubic pain, and pyuria generally depend on the age of the person infected and the location of the urinary tract infected. The main objective of this study was to investigate the bacterial infections of urinary tract in patients with urolithiasis. The patients were referred to and/or visiting the Urology Department in Tikrit Teaching Hospital in Tikrit city.(13

Definition of terms

Urinary tract infection: Infection and microbial colonization of urinary tract. Cystitis: Infection limited to urinary bladder/lower urinary tract. It often presents with dysuria, urinary urgency, frequency, and/or suprapubic pain.

Pyelonephritis: Infection of the kidney/upper urinary tract. It often presents with fever, tachycardia, chills or rigors, costovertebral tenderness, and/or flank pain with or without symptoms of cystitis.

Uncomplicated UTI: Acute, sporadic or recurrent lower (uncomplicated cystitis) and/or upper (uncomplicated pyelonephritis) UTI, limited to nonpregnant, premenopausal women with no known relevant anatomical and functional abnormalities within the urinary tract or comorbidities.(14

Complicated UTIs: UTIs in a patient with an increased chance of a complicated course, that is, all men, pregnant women, patients with relevant anatomical or functional abnormalities of the urinary tract, indwelling urinary catheters, renal diseases, and/or with other concomitant immunocompromising diseases.(15

Prevalence and susceptibility of uropathogens

Culture yielded a total of 189 (42.66 %) significant growths of uropathogens including 179 (94.71 %) unimicrobial (single bacterial species) and 10 (5.29 %) polymicrobial (pair of two different bacterial species) growths. Gender distribution showed 34.44 % male and 48.29 % female UTI patients with male to female ratio of 1:1.46, respectively. E. coli was the predominant isolate (59.30 %), followed by Staph saprophyticus (19.09 %), Enterococcus spp. (11.56 %), Klebsiella spp. (5.53 , Pseudomonas spp. (2.01 %), Proteus spp. (1.51 %) and Enterobacter spp. (1.00 . Very high frequency of resistance ranging from 72.03 to 91.53 % to cotrimoxazole, ciprofloxacin, cefuroxime, cephradin, amoxicillin and nalidixic acid, moderately high resistance to ceftriaxone (55.08 %) and gentamicin (40.68 %) and low resistance to nitrofurantoin (16.10 %) were shown by E. coli. Similarly, Staph. saprophyticus and Enterococcus spp. showed low resistance (18.42 and 21.74 %) to nitrofurantoin, but moderately high against cefaclor, gentamycin, cefuroxime and ceftriaxone. Klebsiella spp. and Proteus spp. were 72.73 and 66.67 % susceptible, respectively to gentamycin only but low frequency of susceptibility (<50 %) was found to all other antimicrobial agents. Peudomonas spp. was 75 % susceptible to nitrofurantoin only and showed 75–100 % resistance to all other agents. Enterobacter spp. were 50 % resistant to nitrofurantoin, gentamycin, cefuroxime, cefaclor and ceftriaxone but showed 100 % resistance to all remaining antimicrobials.(16 (

Current uropathogens showed the highest rate of susceptibility to nitrofurantoin and gentamicin which can be adapted for empirical treatment of urinary tract infections.

Background

Urinary tract infection (UTI) remains as one of the most common bacterial infections and second most common infectious disease in community practice with approximately 150 million diagnosed cases each year. Presence of more than 105 organisms per ml in a midstream sample of urine refers to significant bacteriuria and caused mainly by normal bowel flora, Escherichia coli, which is responsible for over 75 % of cases. Other members of Enterobacteriaceae and a few Gram positive bacteria like Staphylococcus saprophyticus and Enterococcus faecalis are also responsible for UTI. Usually most of the urinary tract infections are caused by a single bacterial species but polymicrobial infections may also take place. It is estimated that about 35 % of healthy women suffer from symptoms of urinary tract infection at some point in their life. The incidence of UTI is greater in women as compared to men, which may be either due to anatomical predisposition or other host factors. Vaginal colonization with uropathogens precedes most UTIs and sexual activity, pregnancy, obstruction are among the other factors contributing to increasing frequency of UTI in female.(17

Indiscriminate use of antimicrobial agents is a common practice in underdeveloped and many developing countries that often leads to emergence of resistant microorganisms to one or several of these agents with gradual narrowing of scope for effective molecules to combat bacterial infections including UTIs. As a common practice, empirical antimicrobial treatment is initiated before the laboratory results of urine culture are available which may lead to emergence and spread of antimicrobial resistant strains. Factually antimicrobial resistance is one of the principal causes of treatment failure in infectious diseases and a great concern for UTIs. The prevalence and pattern of antimicrobial susceptibility of uropathogens are dependent on many factors and constantly changing with the ever increasing use of antimicrobials, continuous monitoring of the susceptibility pattern is of paramount importance for not only selecting appropriate drugs but also for rational choice of empirical therapy. The present investigation was carried out to determine the recent status of prevalence of bacterial pathogens and their antimicrobial susceptibility in UTI patients with the aim to disseminate information about choice of empirical antibiotics.(18

Urinary tract infection (UTI)

It is a bacterial infection that affects part of the urinary tract. When the lower section affects the urinary system it is known simply as cystitis (infection of the bladder)

and when it affects the upper part of the urinary system it is known as pyelonephritis (kidney infection). Symptoms related to the lower section infection include the urinary system painful urination associated with either frequent urination or need To urinate (or both), while symptoms related to pyelonephritis include both fever and pain in the loin as well as symptoms of urinary tract infection. Symptoms may be vague or not specific for the elderly or the very young. The main factor causing both infections is Escherichia coli, but in rare cases it is possible that other bacteria, other virus (s) or other fungi are the cause.(9)

Fag 1 Multiple white blood cells appear in the urine of a person with urinary tract infection through a urine microscopy.

Urinary tract infections are more common in women than men, with half of women contracting at least once at some point in their lives. It is also common to repeat the infection. Risk factors include the female anatomical nature, sexual relationship, and family history. If pyelonephritis occurs, it usually follows a bladder infection but may also result from a blood-borne infection. Diagnosis in healthy young women may be based on symptoms alone. For those with vague symptoms, it may be difficult to diagnose their condition because bacteria may be present without infection. In complex cases or if treatment fails, a urine culture may be beneficial.

For those who suffer from recurrent infection, a low dose of antibiotic can be taken as a preventive measure.(12)

Fag2 Urine may contain pus (a condition known as purulent albuminuria) as seen in a person with sepsis due to a urinary tract infection

In cases without complications, the urinary tract infection is easily treated with a short course of antibiotics, despite increasing resistance to many antibiotics used to treat this condition. In complicated cases, treatment with antibiotics may be required for a longer period or by intravenous injection, and if symptoms do not improve within two or three days, further diagnostic tests should be performed. In women, urinary tract infection is the most common form of bacterial infection, with 10% of them getting urinary tract infections annually.(20)

Case presentation

A 27-year-old man, previously healthy, presented to the Emer- gency Department (ED) in October 2018 for 1-day history of susceptibility to all the tested antimicrobials: amikacin, aztre- onam, cefixime, ceftazidime, imipenem, norfloxacin, trimetho- prim/sulfamethoxazole, cefamandole, levofloxacin, tetracycline, amoxicillin-clavulanate, cefepime, cefuroxime, ciprofloxacin, gen- tamicin, nitrofurantoin, piperacillin/tazobactam, and ampicillin. The susceptibility testing was controlled using the quality control Escherichia coli strain, ATCC 25922. The patient follow up 3 days after discharge indicated the resolu- tion of symptoms along with a negative urine analysis and culture. To try tracing the source of this pathogen, a detailed history was taken, and the patient denied exposure to marine animals, water activities, and eating raw fish. The patient was asked to deliver water being used at home for culture. Two samples were pre- sented and examined: A normal home tap water and a well water (salt water) . albensis was recovered from both analyzed water samples, in combination with mixed microor- ganisms: Pseudomonas otidis, Aeromonas hydrophila, Enterobacter cloacae, Escherichia coli, and Shewanella putrefaciens.(21)

Methods

Demographic data

The mean age of the patients in this study was 45.34 ± 23.56 (SD) years; (range 3 months to 95 years). There were 242 (60.2%) females and 160 (39.8%) males. The prevalence of UTI in the females was more homogenous between age groups, considering intervals of 10 years, with small difference after the third decade, and few children was diagnosed. Fifty percent of the male patients were older than 60 years and the distribution was almost constant in the younger decades (Table 1).(22)

Pathogens

The most commonly isolated organism was Escherichia coli (58%). Klebsiella sp. (8.4%) and Enterococcus sp.(7.9%) were reported as the next most common organisms. The others bacteria are summarized in Table 2.

Bacterial susceptibility

The comparison of the susceptibility pattern of organisms to various antimicrobial agents from all the specimens was shown in Table 3. Escherichia. coli showed high susceptibility to aminoglycosides: amikacin (97%) and gentamicin (94%); to nitrofurantoin (89%); fluoroquinolones: norfloxacin (81%), ciprofloxacin (78%) and levofloxacin (91%); second and third generation cephalosporins and imipenem. There was a low susceptibility pattern of E. coli to ampicillin (41%), trimethoprim- sulfamethoxazole (TMP-SMX) (50%) and cephalothin (58%).(22)

Klebsiella sp was highly susceptible to aminoglycosides: gentamicin (91%) and amikacin (84%); to cephalosporins: cefoxitin (96%), cefotaxime (90%) and

ceftriaxone (88%). Nevertheless, there was a decreased susceptibility to nitrofurantoin (50%), norfloxacin (68%), ciprofloxacin (71%), cefalothin% (58 , TMP-SMX (58%) and ampicillin% (6 Enterococcus sp. showed high sensibility to nitrofurantoin (100%), penicillin G (100%), vancomycin (100%) e ampicillin (96%) The resistance to TMP-SMX was high, approximately 70% (Table 3).(22)

Percentage of susceptible micro-organisms

Of all bacteria isolated from community acquired urinary tract infection, only 37% were sensitive to ampicillin, 51% to cefalothin and 52% to TMP-SMX. The highest levels of susceptibility were to imipenem (96%), ceftriaxone (90%), amikacin (90%), gentamicin (88%), levofloxacin (86%), cefoxitin (80%) nitrofurantoin %(77%), norfloxacin (75%) and ciprofloxacin (73%)-(Table 3).(22

Conclusions

UTI’s in urolithiasis was more frequent in females than males and the percentages were 28/45 and 17/45 respectively. The most effective antimicrobial agent was amikacin and the least effective one was ampicillin, whereas ciprofloxacin, cefoxitin, levofloxacin, nitrofurantoin, nalidixic acid, chloramphenicol, amoxicillin and gentamicin were effective at different levels. Urinary tract infection occurs in every age and in both genders. According to the demographic data, it is more frequent in woman12.(9)

The present study is retrospective, using the results of our routine diagnostic and susceptibility analysis. These data are from a tertiary hospital, the patients are screened in the primary and secondary level of healthy system and prone to

associated conditions and diseases. These factors may influence the patterns of the data herein presented. We are concerned about the necessity of periodical re- evaluation of bacterial etiology and antibiotic resistance in each health unit and of a national surveillance to avoid the rise of the antimicrobial resistance. In the community, it is important to guide the general practitioners that generally treat empirically the UTI, for what they need to be aware of the locally prevalent strains and their sensitivity pattern. Geographic variations in pathogen occurrence and susceptibility profiles require frequent monitoring to provide information to guide the therapeutic options. Unfortunately, there is few studies published on the prevalence of strains and their antimicrobial susceptibilities in Brazil.(4)

We found that E. coli is the predominant bacterium in urine samples, corresponding to 58% of the cases. This is in accordance with previous studies13-15, however in a study from Norway16 E. coli caused 81.5% of UTI in outpatients compared to 58% in the present study. A lower proportion of UTI was caused by Klebsiella sp (8.4%) and Enterococcus sp (7.9%), which is in accordance to others12,13,15. E. coli exhibited resistance to the commonly used antibiotics, and the most effective in-vitro agents were found to be aminoglycosides: amikacin (97%) and gentamicin (94%) among the injectables; and fluoroquinolonas: norfloxacin (81%), ciprofloxacin (78%) and levofloxacin (91%) among the orally administered ones. Other useful oral antibiotic is nitrofurantoin (89%). The organisms showed resistance to common used urinary antibiotics like ampicillin (59%), TMP-SMX (50%) and cephalothin (42%), in disagreement with data published by others13,17,18. In summary, fluoroquinolones remains the choice among the orally administered antibiotics, followed by nitrofurantoin, second and third generation cephalosporins. To treat severe illness one may use the injectable antibiotics, and among then, we should choice aminoglycosides, third generation cephalosporin, fluoroquinolones or imipenem, which were the most effective ones. The high resistance patterns to ampicillin, cephalotin and TMP-SMX should be remembered

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