Subarachnoid hemorrhage (SAH) accounts for about 5% - 10% of stroke, with high disability rate and mortality rate. 10% of patients were sudden death due to intracranial hypertension, with a mortality rate of 30% within 30 days. The survivors left varying degrees of dysfunction. The patients are prone to urinary tract infection because of its acute onset, serious condition, consciousness, retained catheterization, don’t move and staying in bed for a long time during the treatment period and the immune function decreased. And complications such as infection could aggravate its mortality [1] . Therefore, effective control of infection and reduced mortality and complications are also important measures for the treatment of subarachnoid hemorrhage. Among them, urinary tract infection is one of the major infection sites. Bogossian et al. reported that the incidence was 15.7% [2] . Targeted treatment is to select sensitive antibiotics according to the results of urine culture and drug sensitivity test, but it will take 2 - 3 days. Before that, clinicians must carry out anti-infection treatment according to experience. If the treatment is unreasonable or incomplete, it will lead to an increase of bacterial drug resistance, especially the generation and rapid spread of multi-drug resistant strains, which will bring difficulties to the treatment of patients. Although the incidence of urinary tract infection in patients with subarachnoid hemorrhage has been reported, the specific bacterial type and antibiotic sensitivity have not been reported. In order to better understand the distribution and drug resistance of pathogens of urinary tract infection in patients with subarachnoid space, provide basis for clinical selection of antimicrobial treatment and guide clinical rational drug use, we analyzed retrospectively the positive bacterial strains and drug sensitivity test of subarachnoid hemorrhage patients with urinary tract infection in our hospital from January 2019 to July 2024.

The incidence of urinary system infection ranks second among hospital acquired infections in China, with a constituent ratio of about 10.9% [3] . Subarachnoid hemorrhage is a very serious stroke with acute onset, rapid progress, high mortality and disability. The proportion of indwelling catheterization is high in patients because there is the high incidence of consciousness and long time in bed; meanwhile, patients with subarachnoid hemorrhage often have low resistance because old age and accompanied by hypertension or diabetes; and perineum can not be kept clean and sanitary. These factors can easily lead to urinary tract infection in patients with subarachnoid hemorrhage. In our data, we also found that the incidence of urinary tract infection in 716 patients with subarachnoid hemorrhage was 4.61%. It is much higher than that of hospitalized patients with other diseases [4] . This conclusion can be also confirmed. Complications such as urinary tract infection aggravate the mortality and prolong the hospital time, thus forming a vicious circle. Therefore, effective control of infection and reduce mortality and complications are also important measures for the treatment of subarachnoid hemorrhage. Targeted treatment is to select sensitive antibiotics according to the results of urine culture and drug sensitivity test, but it will take 2 - 3 days. Before that, clinicians must carry out anti-infection treatment according to experience. If the treatment is unreasonable or incomplete, it will lead to the increase of bacterial drug resistance, especially the generation and rapid spread of multi-drug resistant strains, which will bring difficulties to the treatment of patients. In order to better understand the distribution and drug resistance of pathogens of urinary tract infection in patients with subarachnoid space, provide basis for clinical selection of antimicrobial treatment and guide clinical rational drug use, we analyzed the species, distribution, sensitivity and drug resistance of infectious pathogens of subarachnoid hemorrhage with urinary tract infection in our hospital in the past 5 years, so as to select effective antibiotics and nursing measures.

Among the 42 strains of pathogens, gram-negative bacilli accounted for a large proportion, accounting for about 69.04%. Among them, 15 strains of Escherichia coli, accounting for 35.71%; 5 strains of Klebsiella pneumoniae, accounting for 11.91%; 53 strains of Proteus mirabilis, accounting for 7.14; 1 strain of Enterobacter cloacae, accounting for 2.38%; 3 strains of Pseudomonas aeruginosa, accounting for 7.14%, 2 strains of Acinetobacter baumannii, accounting for 4.76%. Among gram-positive cocci, 5 strains of Staphylococcus epidermidis accounted for 11.91%: followed by 3 strains of Enterococcus faecalis, accounting for 7.14%. Secondly, fungal urinary tract infection has increased in recent years. This data showed that there were 1strains of Candida albicans. At present, the incidence of Candida infection has increased rapidly. Hospital acquired Candida has become one of the common pathogens of urinary tract infection [5] .

The main causes of subarachnoid hemorrhage complicated with urinary tract infection are the following two points. One is neurogenic bladder, the second is the change of the drainage mode of urinary retention. The main reason is indwelling catheterization. The indwelling catheterization may destroy the barrier and defense effect of the urethra and bladder mucosa on bacteria, leading to some bacteria can adhere to the urinary tract and combine to the glycoprotein receptors on the surface of the urinary tract epithelial cells, resulting in urinary tract infection [6] . Escherichia coli that the most common pathogen of urinary tract infection, produces extended spectrum β-Lactase (ESBL) that can decompose not only penicillin antibiotics but also cephalosporins and monoamide antibiotics [7] , therefore, it is very easy to develop drug resistance. Pseudomonas aeruginosa infection is a common iatrogenic infection, and its drug resistance is gradually increasing, and it is one of the refractory urinary tract infections. The main cause of Pseudomonas aeruginosa infection may be the concomitant infection of catheter after long-term indwelling catheter or cystostomy Staphylococcus epidermidis is the main form of Staphylococcus infection, because staphylococcus mainly forms a hierarchical functional biofilm through the adhesion, aggregation and proliferation of urinary catheters, which encapsulates the bacteria, so that the bacteria can not only escape the immune damage of the host, but also resist the effects of a variety of antibiotics.

According to the results of drug sensitivity analysis: among gram-negative bacilli, Escherichia coli was most sensitive to imipenem and aztreonam; however, it is less sensitive to ceftazidime, levofloxacin and amikacin; Klebsiella pneumoniae was most sensitive to imipenem, and nitrofurantoin; Pseudomonas aeruginosa was more sensitive to imipenem and aztreonam. Among gram-positive bacteria, most of them have poor sensitivity to antibiotics and are prone to drug resistance. Enterococcus faecalis had high resistance to penicillin (100%) and erythromycin (100%), Staphylococcus epidermidis had high resistance to penicillin (100%) and erythromycin (80%), and Enterococcus faecalis and Staphylococcus epidermidis were generally sensitive to vancomycin and imipenem (100%).

In conclusion, the incidence of secondary urinary tract infection in subarachnoid hemorrhage patients is high, and it is increasing with the extension of hospitalization time, invasive operation, decline of body resistance and self-care ability, which is worthy of clinicians’ great attention [1] . The isolated strains of urinary culture from patients with urinary tract infection are mainly gram-negative bacteria, especially Escherichia coli, which is still the main pathogenic bacteria, while gram-positive cocci and fungal infection are not uncommon, and the sensitivity rate of strains to antibiotics gradually decreases due to the unreasonable application of antibiotics, drug-resistant strains gradually increase, and the dilemma of repeated multi-drug-resistant bacterial infection appears. Therefore, for patients with subarachnoid hemorrhage with urinary tract infection, samples should be collected in time, bacterial culture and drug sensitivity test should be carried out, and effective antibiotics should be selected to improve the treatment effect, prevent and control the occurrence of secondary urinary tract infection, but before the results come out, possible effective drugs can be selected according to the local and hospital bacterial spectrum and antibiotic sensitivity. For the hospital, before the results of the drug sensitivity test are available, whether it is gram-negative or gram-positive bacteria, imipenem or aztreonam can be chosen first.

Of course, this study had limitations. First, it was a single-center study, and the results may not reflect the patient care practices at other hospitals. Second, the data collection was a secondary analysis of a database not collected specifically for the purpose of this study; therefore, the conclusion also has certain limitations. At the same time, this study did not explore specific risk factors for infection and effective preventive measures, which will be further improved in the next prospective study.