Title : Five-Year Prevalence of Hospital Acquired Blood Stream Infections in a Tertiary Hospital in Oman: A Cross-Sectional Study
Background: Several reports have emerged addressing the burden and the prevention of hospital acquired bloodstream infections (HA-BSI); however, they have been largely limited to developed countries. In Arab countries, however, few studies have emerged on various aspects of HA-BSIs. To our knowledge, there have been no reports of the prevalence rate of HA-BSI among admitted patients from Oman. This study aims to explore the HA-BSI prevalence estimates over selected socio-demographic characteristics among admitted patients at a tertiary hospital in Oman over five years of follow-up. The regional variations in Oman were also examined in this study.
Methods: This hospital-based cross-sectional study reviewed reports of colonoscopies performed over 5- years of retrospective follow-up at a tertiary hospital in Oman. HA-BSI prevalence estimates were calculated over age, gender, governorate, and time of follow-up. Cumulative frequency of participants with single and mixed infections and types of causative micro-organisms of HA-BSIs were also obtained. Results: A total of 1246 HA-BSI cases were enumerated among 139,683 admissions to SQUH during the five years of retrospective follow up, yielding an overall HA-BSI prevalence estimate of 8.9 cases per 1000 admissions (95%CI: 8.4, 9.4). Gender-specific HA-BSI prevalence among males was higher than that among females (9.3 vs. 8.5). The age-specific HA-BSI prevalence estimates started as relatively high at group aged 15 years or less (10.0), and then declined as age increased to 36 to 45 years (7.0) when it started to increase steadily with increasing age to the group aged 76 or more (9.9). Regional HA-BSI prevalence was highest among admitted patients who resided in Dhofar Governorate (11.8) while the lowest was among patients from Buraimi governorate (5.3). Over the 5-years of follow-up, there was a slow-declining reduction of HA-BSI prevalence. Conclusion: The study provides supportive evidence for a varying slow reduction in HA-BSI prevalence over age categories and years of follow up; and depicted the variations of gender-specific CRC prevalence estimates over increasing age categories. The study calls for further reinforcement of infection prevention and control measures to reduce these rates further. Keywords: hospital acquired bloodstream infections, HA-BSI, Prevalence, Oman
Hospital acquired bloodstream infections (HA-BSIs) are one of the most serious hospital acquired infections. HA-BSI constitutes a global challenge [1-5]. Surveys have shown that HA-BSIs were responsible for 20%-60% of hospitalization related deaths [6, 7]. In the United States, HA-BSIs represents 10% of Hospital-acquired infections (HAIs) and is considered the eleventh cause of death with 99,000 deaths annually from 1.7 million who have contracted HAIs . In some of the Western Europe countries, BSIs result in fatality among two-thirds of the annual 25,000 deaths. Though HA-BSIs are endemic globally, a report on its prevalence is limited particularly from developing countries. Several reports have come from developed countries Initiatives addressing the burden and the prevention of this disease has largely been limited to developed countries. There is urgent need to document the pattern of HA-BSIs in emerging economies since the bulk of the global population concentrates on these developing countries. There are some preliminary data indicating that, in addition to dearth of studies, those regions appear to have suboptimal patient safety measures including infection control practices [11-13]. Studies by Al-Rawajfa  and Jumaa  indicated a rampant incompliance with safety measures. Due to limited resources and safety culture , the prevailing health situation in developing countries would appear bleak in the foreseeable future . Therefore, studies on various aspects of patient safety including hospital acquired infections are needed. Studies addressing burden of hospital acquired infections including prevalence of HA-BSIs and its microbial pathogens in developing countries is critical so that preventive measures could be contemplated. Among the developing countries in the Middle East and North Africa, some studies have started to quantify the burden of BSI [11, 14, 16-19]. In the Middle East, there is one region with defined social and economic union known as the Gulf Cooperation Council (GCC), in which some studies have emerged on various aspects of HA-BSIs [11, 18, 20-29]. To our knowledge, there are no published studies on HA-BSI in Oman. Previous reports have suggested that HA-BSIs may be prevalent in Oman [30, 31], including multi-drug resistant organisms . In order to lay the groundwork for evidence-based policies for prevention and management, this study endeavored to explore the HA-BSI prevalence estimates among admitted patients at a tertiary hospital in Oman over five years of follow-up. The interrelated objectives of this study are: 1) to describe 4 the socio-demographic and clinical characteristics of HA-BSI cases among admitted patients, and 2) to provide HA-BSI prevalence estimates with regard to socio-demographic categories such as age, gender, governorate, and time of follow-up.
Study design For the purpose of the study, an ambi-directional hospital-based cross-sectional study of HA-BSIs has been undertaken in Sultan Qaboos University Hospital (SQUH) in five years period of time from January 2015 to 2019. SQUH is a 570-bed, tertiary care teaching hospital in Muscat, Oman receiving its referrals from regional secondary and primary centers located in the 7 Omani governorates; (Muscat, Batinah, Dakhliya, Shjarqiya, Dofar, Dahirah and Buraimi). The hospital includes an Infection Control Unit which is constituted of doctors and nurses specialized in infection control related disciplines. Case definition and ascertainment BSI was diagnosed by one positive blood culture if the isolate is recognized pathogen, one blood culture from (central line) or at least two blood cultures from (peripheral line) if the isolate is one of the common commensals. BSI cases were classified as hospital acquired (according to the CDC definition) if the laboratory confirmed bloodstream infection occurs after 48 hours or more of hospital admission. The study includes all the adults and children patients and newborn with the HA-BSIs during the study period. Newborn with HA-BSI (babies) less than 48 hours born in the hospital and never left the hospital were also included in the study. The reason is that there is no any chance for the infection to be other than hospital acquired. BSI occurred as a result of earlier admission and the patients discharged not more than 48 hours of the previous admission also considered HA-BSI. Data collection The data were collected by reviewing patients’ medical records in the Hospital Information System (HIS). Collected data included socio-demographics, clinical information and microbiological information. All evaluations were reviewed and scored by two clinical investigators who developed and employed a coding guide based on the International Statistical Classification of Diseases and Related 5 Health Problems (ICD) criteria to determine if the HA-BSI labelling was consistent with the standard international diagnostic criteria of BSI. Inter-rater reliability was established among the two clinical investigators to standards of 94% agreement on the overall HA-BSI case status. For ongoing inter-rater reliability checks, a random sample of records (10%) was scored independently by a reviewer experienced clinical working with HA-BSI and did not participate in the diagnostic reviews. Percentage agreement between the raters on the final HABSI case definition was found to be 96%. Statistical analysis We calculated the annual and the total prevalence estimates of HA-BSI per patients and isolates. Prevalence rates of HA-BSI patients were calculated by dividing the number of HA-BSI cases by the total admission and the prevalence rates of HA-BSI isolates were calculated by dividing the number of HA-BSI isolates by the total admission. Prevalence rates were reported per 1,000 admissions. The 95% confidence intervals (95% CI) of prevalence rates were calculated using the Poisson distribution method of binomial variables. A P-value of 0.05 or less was considered as statistically significant. Statistical Package for Social Sciences (SPSS) (version 24.0, IBM) was used for all statistical analyses. Ethical approval for this study was obtained from the Institutional Review Board of Sultan Qaboos University, Medical Research Ethics Committee at College of Medicine and Health Sciences.
Table 1 shows the distribution of the selected socio-demographic and clinical characteristics of admissions enrolled in the study. Overall, there had been 139,683 admissions of which 1246 (0.89%) were HA-BSIs cases. Admitted male patients were slightly higher (71,823; 51.4%). More than half (58.6%) of the admissions were of patients aged below 45 years. Over the years, there has generally been a balanced distribution of total admissions. The majority of admitted patients (34.7%) were residents at Muscat Governorate, followed by Batinah and Dakhliya (18.5% & 13.7%, respectively). Table 1 also compares the selected characteristics among HA-BSIs cases versus “non-cases”. The gender distribution was similar: around 50% among both groups. HA-BSIs cases tended to belong to 6 the younger age group compared to non-cases. The distributions of each governorate of residence and year of procedure request were both comparable among HA-BSIs cases and non-cases. In all comparisons, the differences were not statistically significant (p> 0.05). [Place Table 1 about here] Table 2 shows the frequency and prevalence estimates of HA-BSIs among admitted patients stratified by age and gender. There were 1246 HA-BSI cases among a total of 139,683 admissions to SQUH during the five years of retrospective follow up, yielding an overall HA-BSI prevalence estimate of 8.9 cases per 1000 admissions (95%CI: 8.4, 9.4). The HA-BSI prevalence per 1000 admissions among males (9.3; 95%CI 8.6, 10.0) was higher than that among females (8.5; 95%CI 7.9, 9.3). The age-specific prevalence estimates indicated that the HA-BSI prevalence estimates started as relatively high at group aged 15 years or less (10.0; 95%CI 9.0, 11.2), and then declined as age increased to 36 to 45 years (7.0; 95%CI 5.9, 8.3) when it started to increase steadily with increasing age to the group aged 76 or more (9.9; 95%CI 8.1, 12.1). Figure 1 depicts the distribution of HA-BSI prevalence estimates over increasing age categories. [Place Table 2 about here] [Place Figure 1 about here] Figure 2 depicts the distribution of gender-specific prevalence estimates over increasing age categories. HA-BSI prevalence among males was proportionately higher than that among females over all age categories. HA-BSI prevalence among males started as high among patients aged 15 years or less, it then declined gradually till the age category 36 to 45 years old, when it started to increase steadily, reaching the highest estimate among people aged 70 years or more. The HA-BSI prevalence among females was of steadier pattern over all age categories. [Place Figure 2 about here] Table 3 and Figure 3 show the distribution of HA-BSI prevalence estimates by year of diagnosis over the five-year study period. Overall, it showed a slow-declining reduction of HA-BSI prevalence over 5 years of retrospective follow-up. The highest HA-BSI prevalence estimate (10.1; 95%CI 8.9, 11.3) was reported in the year 2017, while the lowest estimate (7.7; 95%CI 6.8, 8.8) was reported in the year 2019. Figure 3 depicts the trend of HA-BSI prevalence estimates over year of diagnosis. 7 [Place Table 3 about here] [Place Figure 3 about here] Table 4 and Figure 4 show the governorate-specific estimates of HA-BSI prevalence among admitted patients. The highest prevalence estimate per 1,000 admissions was reported among admitted patients who resided in Dhofar Governorate (11.8; 95% CI 10.2, 13.8) followed by Dakhliya (11.4), Sharqiya (10.9), Batinah (9.9), Dhahira (7.7), and Muscat (6.2). The lowest prevalence estimate was reported from Buraimi governorate (5.3; 95%CI 3.5, 9.4). [Place Table 4 about here] [Place Figure 4 about here] Table 5 shows the prevalence estimates of HA-BSI among admitted patients and in isolates, stratified by month of admission. Overall and throughout the period from January to December, a slowrising prevalence trend was observed. The lowest prevalence estimates were observed April (8.5; 95% CI 7.0, 10.4); while the highest estimates were observed in June (8.6 (95% CI 7.2 10.3). Figure 5 illustrates the seasonal trend of occurrence of HA-BSI throughout the year. The prevalence rate of HA-BSI cases and isolates were steady during the period from January to May. In June the prevalence rate increased and then continued fluctuating between decrease and decrease until the end of the year. [Place Table 5 about here] [Place Figure 5 about here] Table 6 shows the frequency distribution of pathogens associated with HA-BSI among admitted patients over five years. Staphylococci are the most prevalent cause of HA-BSIs with 27.7 percent. Klebsiella spp come next after Staphylococci (14.9%) followed by Candida spp with percentage of 9.4. Pseudomonas spp, Escherichia spp and Enterococcus spp come after Candida spp with 7.6%, 7.4% and 6.8%, respectively. Bacteroides spp, Chryseobacterium spp and Citrobacter Spp have contributed equally to HA-BSIs with 0.4% each.The frequency of Staphylococci spp is relatively steady and slight increase occur in 2017 (29.8%). Klebsiella spp kept nearly the same percentage from 2015 until 2017 then suddenly increased in 2018 (18.9%) and decreased in 2019. The frequency of Candida spp infection seems to be fluctuating between increase and decrease during the study period where around 7 % in 2016 and 2018 and about 12% in 2017 and 2019. The three other pathogens (Pseudomonas spp, 8 Escherichia spp and Enterococcus spp) have nearly close proportions and seem to be nearly steady over the study period with a slight increase in 2019.
The earlier view that the advancement of science and technology will help humanity triumph over the vagary of infectious diseases, as previously testified by the World Health Organization’s motto, “Health For All by Year 2000” has largely noted to be untenable aspirant. In a hospital setting, the presence of immunocompromised patients, lack of vigilance to hygiene as well as inherent tendency of medical and surgical procedures to encroach natural protective barriers in the human body all have a trigger proliferation of spreading pathogens. Some developed countries have established infection control strategies with nationwide concurrent surveillance studies which, in turn, have generally mitigated the vagary of nosocomial infections. Some hospitals in some of the Western countries have instituted pay or retribution to health care settings on their vigilant to confront nosocomial infections. There is little evidence to suggest such preventive measures are widespread in developing countries such as Oman. This study was performed to determine the prevalence of HA-BSI in a tertiary care teaching hospital in Oman. The overall prevalence rates of HA-BSI per patients and isolates were 8.9 per 1000 admissions and 11.5 per 1000 admissions, respectively. Similar studies were conducted in US and Europe and slightly lower readings were obtained. In 49 hospitals subjected to a study over a 7-year period in USA, the rate of HA-BSIs was reported to be 6 patients per 1000 admissions (10). Chinese surveillance study reported a prevalence rate of 5.7/1000 admissions in a traditional Chinese medicine hospital (TCMH) (20).
This study is not without its own limitations. First, a non-probability sampling method (convenience sampling) was used to collect the data from one hospital and hence results cannot be generalized to the whole country. Second, the relatively small sample size may have also affected the power of the study to detect significant differences. As a matter of fact, not all observations were statistically significant across 9 categories in the data analysis. Finally, since the study was cross-sectional, the HA-BSI occurrence indices were limited to prevalence only over retrospective follow up which implied lack of temporality and potentially reversed causality. Age-standardized incidence parameters would have been better measures of HA-BSI occurrence with better temporality ascertainment.
In summary, this hospital-based cross-sectional study explored the variation in the prevalence of HA-BSI among admitted patients in a tertiary hospital in Oman over 5 years of retrospective follow-up. The study provides supportive evidence for a varying slow reduction in HA-BSI prevalence over age categories and years of follow up; and depicted the variations of gender-specific CRC prevalence estimates over increasing age categories. The study calls for timely formulation and adoption of national HA-BSI screening programs centered on increasing awareness of HA-BSI and considering screening as a primary prevention in order to respond to the increase in HA-BSI prevalence in Oman and other Arab countries.