Microorganisms causing urinary tract infections in a teaching hospital in northeastern Brazil

Objective: to study the UTI-causing bacteria frequency and sensitivity profiles in a teaching hospital in northeastern Brazil. Method: A retrospective cross-sectional study was conducted based on the review of 279 patients for whom uroculture and urinary catheter cultures were routinely processed in the Microbiology Laboratory of São Vicente de Paulo Hospital. Results: For the catheter culture group, the most frequent microorganism was Staphylococcus epidermidis (47%), while in urine culture group Escherichia coli was the microorganism most frequently isolated (52%). E. coli showed 76.46%, 70%, and 86.36% resistance to ampicillin, amoxicillin and Sulfamethoxazole/trimethoprim respectively. S. epidermidis showed high resistance to most drugs used, demonstrating that these drugs should not be used to treat UTIs in this institution. Conclusion: This study represents the first study evaluating bacterial resistance in this institution and since data involving epidemiological surveillance and microbiological are limited in this region and due Acadêmica de Medicina da Faculdade de Medicina Estácio de Juazeiro do Norte – Estácio FMJ. Juazeiro do Norte, Ceará, Brasil. E-mail: tuyanne_alves@hotmail.com ORCID ID: https://orcid.org/0000-0003-4061-1079. Acadêmica de Medicina da Faculdade de Medicina Estácio de Juazeiro do Norte – Estácio FMJ. Juazeiro do Norte, Ceará, Brasil. E-mail: cecilia_brenda@hotmail.com ORCID ID: https://orcid.org/0000-0002-3576-5957. Acadêmico de Medicina da Faculty of Sciences Health, The University of British Columbia (UBC), Vancouver, British Columbia, Canadá. E-mail: michaelpeters@gmail.com ORCID ID: https://orcid.org/0000-0002-3652-3220. Acadêmico de Medicina da Faculdade de Medicina Estácio de Juazeiro do Norte – Estácio FMJ. Juazeiro do Norte, Ceará, Brasil. E-mail: carlos_igt@yahoo.com.br ORCID ID: https://orcid.org/0000-0002-1322-7509. Acadêmica de Medicina da Faculdade de Medicina Estácio de Juazeiro do Norte – Estácio FMJ. Juazeiro do Norte, Ceará, Brasil. E-mail: paula_karinny@hotmail.com ORCID ID: https://orcid.org/0000-0001-7739-910X. Acadêmico de Medicina da Faculdade de Medicina Estácio de Juazeiro do Norte – Estácio FMJ. Juazeiro do Norte, Ceará, Brasil. E-mail: juniorjua3@hotmail.com ORCID ID: https://orcid.org/0000-0002-8439-0610. Acadêmica de Medicina da Universidade de Cuiabá (UNIC). Cuiabá, Mato Grosso, Brasil. E-mail: yasminecgarcia@hotmail.com ORCID ID: https://orcid.org/0000-0002-6339-5543. Farmacêutico. Bioquímico e Microbiologista do Hospital Maternidade São Vicente de Paulo. Barbalha, Ceará, Brasil. E-mail: paulojean@hotmail.com ORCID ID: https://orcid.org/0000-0001-8571-9484. Farmacêutica. Pós Doutora. Professora de microbiologia e farmacologia da Faculdade de Medicina Estácio de Juazeiro do Norte – Estácio FMJ. Juazeiro do Norte, Ceará, Brasil. E-mail: adilfabio@hotmail.com ORCID ID: https://orcid.org/0000-0001-6160-6725. Autor principal – Endereço para correspondência: Rua Maria Alves de Oliveira, 74, Bairro Alto do Jucá, Iguatu CE, Brasil. Chaves TA, Carneiro CBR, Peters M, Araújo CNA, Alencar PKM, Ferreira AJL, et. al. Microorganisms causing... Journal Health NPEPS. 2018; 3(1):51-66. 52 to its importance in the national context, the results may reflect important information to the body of research/data on bacterial resistance in the world. Descriptors: Infection; Urine; Anti-Bacterial Agents. RESUMEN Objetivo: estudiar los perfiles de frecuencia y sensibilidad de las bacterias causantes de ITUs en un hospital universitario del nordeste brasileño. Método: Se realizó un estudio retrospectivo de corte transversal, con base en la revisión de 279 pacientes, para los cuales las culturas de urocultura y catéter urinario fueron analizadas en el Laboratorio de Microbiología del Hospital São Vicente de Paulo. Resultados: En el grupo de cultivo de catéteres, el microorganismo más frecuente fue el Staphylococcus epidermidis (47%), mientras que en el grupo de la urocultura la Escherichia coli fue el microorganismo más aislado (52%). La E. coli mostró 76,46%, 70% y 86,36% de resistencia a la ampicilina, amoxicilina y sulfametoxazol/trimetoprima, respectivamente. S. epidermidis mostró una alta resistencia a la mayoría de los fármacos utilizados indicando que los medicamentos en cuestión no deben ser usados en el tratamiento de ITUs en esa institución. Conclusión: Este estudio representa el primer estudio que evalúa la resistencia bacteriana en esa institución y una vez que los datos que involucran vigilancia epidemiológica y microbiológica son limitados en esta región y debido a su importancia en el contexto nacional, estos resultados pueden reflejar informaciones importantes para el cuerpo de búsqueda/datos sobre resistencia en el mundo. Descriptores: Infección; Orina; Antibacterianos. RESUMO Objetivo: estudar os perfis de frequência e sensibilidade das bactérias causadoras de ITUs em um hospital universitário do nordeste brasileiro. Método: Foi realizado um estudo retrospectivo de corte transversal, com base na revisão de 279 pacientes, para os quais as culturas de urocultura e cateter urinário foram analisadas no Laboratório de Microbiologia do Hospital São Vicente de Paulo. Resultados: no grupo de cultura de cateteres, o microrganismo mais frequente foi o Staphylococcus epidermidis (47%), enquanto no grupo da urocultura a Escherichia coli foi o microrganismo mais isolado (52%). A E. coli mostrou 76,46%, 70% e 86,36% de resistência à ampicilina, amoxicilina e sulfametoxazol/trimetoprima, respectivamente. S. epidermidis mostrou uma alta resistência à maioria dos fármacos utilizados indicando que os medicamentos em questão não devem ser usados no tratamento de ITUs nessa instituição. Conclusão: Este estudo representa o primeiro estudo que avalia a resistência bacteriana nessa instituição e uma vez que os dados que envolvem vigilância epidemiológica e microbiológica são limitados nesta região e devido a sua importância no contexto nacional, estes resultados podem refletir informações importantes para o corpo de pesquisa/dados sobre resistência no mundo. Descritores: Infecção; Urina; Antibacterianos.

to its importance in the national context, the results may reflect important information to the body of research/data on bacterial resistance in the world.Descriptors: Infection; Urine; Anti-Bacterial Agents.

Exponential advances in healthcare technology has led to an increase in the sensitivity of disease detection and as a result, overtreatment, which has invariably led to increased hospitalization and complications, infections
secondary to instrumentation being common 1

RESULTS AND DISCUSSION
In the period from January to December 2012, 279 samples were cultured, of which 84 were positive.Of the 55 catheter samples, 69.90% had microbial growth.Of the 225 urine culture samples, 21% had microbial growth (Figure 1).41 of these patients had a community-acquired UTI, and 43 had a hospital-acquired UTI.
Most hospital-acquired urinary tract infections are closely related to catheter use, Catheter-associated (CA)-bacteriuria is the most frequent health care-associated infection worldwide, Being responsible for up to 40% of hospitalacquired infections in US hospitals each year 10 .A study in Brazil showed that 35% to 45% of nosocomial infections in Brazilian hospitals are UTIs 11 , and of these 80% are related to catheterization, which is the main risk factor and transmission vehicle.
Furthermore, it is estimated that patients catheterized for more than 30 days (long-term catheterization) nearly all of them will experience bacteriuria 3,12 , despite adequate aseptic technique and closed drainage systems.The risk of acquiring bacteriuria occurs between 3% and 8% per day of catheterization, demonstrating the cumulative risk of infection over the days of catheterization 3 .
The high percent of positive cultures (69.90%) in our samples support the findings of the study.
Our findings can also be compared to similar studies carried out in other Brazilian territories by authors Vieira et al. 13 in the state of Pará, Kazmirczak, Giovelli and Goulart 14 in the state of Rio Grande do Sul, Costa et al 15 in the state of Paraiba.
For the adequate treatment of urinary infections it is essential to identify the causative bacteria, which aids in antibiotic selection 16 .
Such findings may be justified by the fact that Staphylococcus epidermidis is a microorganism that is naturally found in the skin.However, S. epidermidis has been increasingly associated with critical infections due to the formation of bacterial biofilms in medical devices such as prostheses, valves, and catheters 16 .
While Escherichia coli is a commensal bacterium in the intestines of humans, the anatomical proximity of the anus to the urethra, the main entry point of urinary pathogens, causes this organism to be a significant source of UTIs 17 .Moreover, E.
coli has several attachment factors, such as several adhesins and pilis that allow it to better adhere to uroepithelium.While adherence to epithelial cells is essential for successful colonization and establishment; its virulent capacity is expressed by other encoding toxins, lipopolysaccharide (LPS), capsule, and invasins 18 .

With regard to the contamination of vesical catheters by Staphylococcus epidermidis, it currently ranks the first among the causative agents of biofilmrelated nosocomial infections, where the organism promotes extraluminal colonization of catheters with high antibiotic resistance. Moreover, the mechanism involved in the accumulation of staphylococcal biofilms remains not yet fully understood, it varies by strain as well as environmental conditions, which
hinders the effectiveness of a specific treatment 16,[19][20][21][22] .However, it is important to mention that Klebsiella pneumoniae, a gram-negative pathogen, was the second most frequent bacterium in patients using catheters.Furthermore, this correlates well with literature, as it the second most frequently isolated pathogen in cases of nosocomial UTIs 23 .

Figure 1 -Number of positive samples in urinary catheters (A) and urocultures (B).
The relationship of etiological agents isolated from urocultures presented in Figure 2B showed results similar to those of the SENTRY Antimicrobial Surveillance Program by Sader et al. 24 , which studied the resistance of the main pathogens isolated from 12 Brazilian hospitals in four Brazilian states in a period of three years.Their results showed UTI frequency as follows: 47.6% E. coli, 12.6% P. aeruginosa, 9.8% Klebsiella pneumonia and 5.8% Enterobacter spp.It is important to mention that in our study Pseudomona aeruginosa and Klebsiella pneumonia appear colonizing both catheterized and non-catheterized patients (Figure 2), this finding may be an indicator of alertness, given the increasing mortality related to them and their high resistance rates to multiple antimicrobial drugs.Thus, only an appropriate antibiotic treatment of these infections, based on sensitivity testing and adjusting empirical antimicrobial therapy, will determine a suitable clinical evolution 25,26 .
It is clear that the rational use of antimicrobials should be based on the antibiogram, which allows physicians to make the correct choice of antibiotic based on its sensitivity profile.This approach reduces the rates of bacterial resistance and facilitates the correct choice of antibiotic for each patient.
For the prudent choice of antibiotic agents, some factors must be taken into account, such as clinical efficacy against a particular group of bacteria, local resistance, and costs.Such selection has been quite effective in controlling infection, whether at the community or hospital level.
Escherichia coli was the most resistant bacterium in this study, with a resistance of 76.46% to the use of ampicillin, 70% to the use of amoxicillin, and 86.36% to the use of sulfametazol/trimetroprim (SMZ-TMP) (Table 1).It is important to say that this high resistance associated with Escherichia coli would be expected since this bacterium represented 52% of all the microorganisms isolated in the uroculture samples (Figure 2B).These results were confirmed in part by Blatt and Miranda et al. 27 , where Escherichia coli resistance was 60.4% for ampicillin and 54.7% for SMZ-TMP.
Regarding the highest resistance index of E. coli to SMZ-TMP in our study, a similar study carried out in northern Utah, USA, showed a resistance of 71.6% 28,29 , while another study carried out in the city of São Paulo, Brazil, showed that 58.3% of the strains analyzed were resistant to this medication 28 , demonstrating the ineffectiveness of this drug for this type of treatment.
Tavares, in 2009 30 , reported that the indiscriminate use of SMZ-TMP in Brazil for the treatment of cystitis would become one of the main factors for the increasing resistance of UTI pathogens, due to change of the endogenous microbiota.
New resistant strains would lead to even greater therapeutic challenges.
Resistance to ciprofloxacin remains low in some areas (0% in nova scotia, Canada), but is found in 72% of isolates in Mexico and 5-10% in the USA 31 .Also troubling is the emergence among patients with community-acquired UTI of E. coli possessing the extended spectrum βlactamase enzymes, which confer resistance against penicillins, third generation cephalosporins, and monobactams.
In a given region, the prevalence of antibiotic resistance can not exceed 20%, according to Warren et al. 32 However, this study shows a resistance rate above 20% for E.coli to cephalosporins and quinolones, making its use non-viable for this population.More recent studies have shown that E. coli presents high resistance rates (>45%) to wide-spectrum penicillins, cephalosporins, aztreonam, and ciprofloxacin 25 .
However in this study, E. coli showed 100% sensitivity to aminoglycosides (amikacin and tobramycin), and carbapenems (meropenem and imipenem).Similar data were reported in the Lago, Fuentefria, and Fuentefria study 33 showing 95% sensitivity, and the Miranda et al. study 34 showing a sensitivity of 100% for the same drugs..
However, some results have shown a varied efficacy of this antibiotic on the bacterial biofilm, which can be explained by its limited penetration into the biofilm matrix, which means a great challenge for clinicians making it difficult or impossible to treat and detachment from the device may result in systemic infections 35 .
In this study, S. epidermidis showed 100% sensitivity to vancomycin, 82.36% to amikacin, and 81.25% to chloramphenicol.Similar results were found by Michelim et al. 36 , where S. epidermidis was 100% sensitive to vancomycin.
However, intermediate resistance to vancomycin has been described 37 .The increasing prevalence of highly virulent and multi-drug resistant bacterial strains constitutes a major concern in modern medicine.Biofilm formation adds an additional compounding factor, making therapy extremely difficult when there is antibiotic resistance in a subpopulation of a biofilmforming species.Pathogenic staphylococci are now regarded in the scientific community as antibiotic-resistant "superbugs," because they have the capacity to acquire resistance traits.
The difficulties of predicting a clinical infection with S. epidermidis in patients with positive blood cultures with this organism may mean management quandary for clinicians, since there are no reliable phenotypic or genotypic algorithms to predict the pathogenicity of an infection of the bloodstream by S epidermidis 38,39 .
Possible targets for drug development include enzymes involved in the biosynthesis of cell envelope structures, such as peptidoglycan, teichoic acids, membrane lipids, or cell wall-associated adhesins 38 .
Epidemiological research is of fundamental importance for the proper use of antimicrobials, since the use of a particular drug in empirical therapy should not be conducted when the level of local resistance is greater than 20% 39