Hospital-acquired infections in a Nigerian tertiary health facility: An audit of surveillance reports.

BACKGROUND: Hitherto efforts to implement data driven prevention guidelines for hospital-acquired infections (HAI) in Nigeria have been limited by the inadequate knowledge of the risks of these infections. This study evaluated the occurrence of HAI in a foremost tertiary health facility over a 5-year period for the purpose of reinforcing control efforts.
MATERIALS AND METHODS: A retrospective survey of records from the infection control unit of the University College Hospital, Ibadan, Nigeria, was done for the years 2005-09. For the 5 years studied 22,941 in-patients were reviewed and the data of those who developed infections during admission were retrieved and analyzed. The prevalence, types, and causative organisms of HAI were determined. The chi-square test was used to evaluate associations.
RESULTS: The prevalence of HAI over the 5-year period was 2.6% (95% CI: 2.4-2.8). Surgical and medical wards had the most infections (48.3%) and (20.5%) respectively. Urinary tract infection (UTI) and surgical site infection (30.7%) were the most prevalent (43.9%) HAI. UTIs were significantly higher in surgical and medical wards, surgical site infections in obstetrics and gynecology wards, and soft tissue infections and bacteremia in pediatric wards (P<0.05). Gram-negative infections occurred about four times as often as gram-positive infections with Klebsiella sp. and staphylococcus aureus being the predominant isolates (34.3%) and (20.1%) respectively.
CONCLUSION: Efforts to limit HAI should be guided by local surveillance data if progress is to be made in improving the quality of patient care in Nigeria.

INTRODUCTION

In the 21st century it is unacceptable that a person who is ill runs the additional risk of acquiring an infection while seeking respite from his present ailment.1 Hospital-acquired infections (HAI) are thus a major patient safety issue as a cause of preventable illness and death. As a result, the prevention and control of these infections have become a priority. Surveillance or monitoring of these infections has been recognized as key to the control of these infections.1

Concern about HAI is global; however, in developing countries where the burden is estimated to be highest, information on surveillance activities in the prevention and control of HCAI is not often available.2 The developments in the surveillance and monitoring of HAI in these countries also lag behind those of more industrialized countries and the mandatory surveillance requirements as it obtains in some other countries have largely not being implemented.3 As a result of this relative lack of information there has been no significant change to improve existing surveillance systems.4–6

In Nigeria also, the inadequate knowledge of the risks of HAI and the measures of risk reduction have limited control activities. To prevent HAIs it is necessary to identify sources and modes of transmission of infection and to implement data driven prevention guide-lines and practices.7 This study therefore aimed to evaluate the pattern and occurrence of HAI in a foremost tertiary health facility over a 5-year period for the purpose of reinforcing control efforts.

MATERIALS AND METHODS

The study was carried out at a foremost tertiary hospital in south west Nigeria by reviewing records from the infection control unit of the hospital for 2005–09. The hospital is an 850-bed hospital with surgical, medical, obstetrics, gynecology, and pediatric departments. Data were primarily collected by the infection control nurses using a surveillance form which documents the results of samples from in-patients who had undergone microscopy culture and sensitivity. These samples had been obtained from patients meeting the criteria for HAI during admission (i.e., infections not present and without evidence of incubation at the time of admission to the hospital). Information on the number of infections, total number of admissions in each ward (including the intensive care unit), sites of infection, and isolated pathogens was obtained from the surveillance forms. Prevalence of HAI was determined for each year based on the number of HAI divided by the total number of admissions. Data were analyzed with Epi-Info 2000. Proportions were determined and the chi-square test was used to explore the differences in the proportions of HAI at a significance level of 5%.

RESULTS

Figure 1 shows the prevalence of HAI for each year studied. Rates climbed slowly from 2.4% in 2005 to 3.1% in 2008; a decline was however noted in 2009 with a rate of 2.3%. The overall prevalence of HAI for the 5-year period was 2.6% (95% CI: 2.4–2.8).

Figure 1

Prevalence of HAI in UCH Ibadan from 2005-09

Distribution of hospital-acquired infections in each ward

The prevalence of HAI in each ward is shown in Table 1. Overall, 48.3% of all infections were from the surgical wards, 20.5% from medical, 15.1% from pediatric, and 16.1% from obstetrics and gynecology wards. The highest ward prevalence of HAI was in surgical wards 4.4% followed by pediatric wards 2.4%.

Table 1

Distribution of HAI by wards in UCH, Ibadan

In each year reviewed, surgical wards consistently recorded the highest prevalence of HAI compared to other wards as shown in Figure 2. HAI peaked in 2008 with the highest prevalence of 5.9% in surgical wards and the least occurrence in obstetric wards at 1.4%.

Figure 2

HAI in each ward in UCH Ibadan for 2005-09

Table 2 shows the cross-tabulation of HAI and type of ward. Surgical wards significantly had more HAI than other wards (P<0.05)

Table 2

Cross-tabulation of HAI and type of ward in UCH, Ibadan

Sites of infections

Table 3 shows the different sites of infections; urinary tract infections occurred most often (43.96%), followed by surgical site infections (30.7%).

Table 3

Sites of hospital-acquired infections in UCH, Ibadan

Hospital-acquired infections by sites of infection in each type of ward

As shown in Figure 3, urinary tract infections were the most common infections in surgical, obstetrics, and gynecology and medical wards. However, soft tissue/cutaneous infections were the most common type of infections in pediatric wards.

Figure 3

HAI by sites of infection in each ward in UCH Ibadan

Isolates from hospital-acquired infections

Gram-negative organisms constituted more than three quarters (78.3%) of all causative organisms in HAI. The isolates from HAI are shown in Table 4. Klebsiella sp. was the predominant isolate (34.3%), followed by staphylococcus aureus (20.1%).

Table 4

Isolates from HAI in UCH, Ibadan

Table 5 shows the isolates from each site of infection. Staphylococcus aureus was the most often isolated organism in surgical site infections (29.2%), bacteremia 45.5%, and burn infections 31.2%. Klebsiella spp. was the predominant isolate in urinary tract infections (42.7%) and soft tissue infections (33.6%). E. coli was the most common organism in meningitis 30%.

Table 5

Isolates by infection sites in UCH, Ibadan

DISCUSSION

The trend of HAI over a 5-year period in a tertiary health facility in Nigeria was presented. Prevalence ranged between 2% and 3% with no significant variation over the 5-year study period. An overall infection rate of 2.6% was found, revealing a slight decline from 3.0% to 4.9% reported in previous clinical audits for the years 1999–2004 and 1989–91 respectively for the same institution.8 This decline may be indicative of better infection control measures in the hospital and recent efforts to limit the duration of hospital stay for in-patients. The observed trend of HAI is comparable to other studies from the country,89 but lower than rates reported from some other countries.10–12 However, direct international comparisons of HAI are often difficult due to methodological differences resulting from definitions of HAI, type of HAI covered and the health units surveyed.4

Consistent with other studies,1314 surgical wards continue to be hot spots for HAI. This is often due to the breached skin defenses resulting from invasive surgical procedures. Urinary tract infections (UTI) emerged as the predominant HAI similar to other studies.131516 Pneumonia and blood stream infections were however not as prominent as reported by some other studies.1718 This can be explained by the infrequent use of central intravenous catheters and mechanical ventilators, making urinary catheters the most commonly used invasive device and hence the high prevalence of UTI as established by other studies.1819

Gram-negative bacilli have been commonly associated with hospital-acquired infections.1220 Our findings also showed a predominance of gram-negative bacilli. A U.S. study reported a similar ratio of gram-negative bacilli to gram-positive cocci as 4:1.21 Staphylococci were also prominent particularly in blood stream infections similar to other studies.22 A noticeable gap in this surveillance system was the lack of routine screening for Methicillin Resistant Staphylococcus Aureus (MRSA) which has been made mandatory in some countries.1

Limitations

Data were not disaggregated by age- or sex-limiting knowledge of demographic variables which might impact on susceptibility to HAI. Although this study was done in the largest tertiary hospital in Nigeria, findings cannot be assumed to be representative of the whole country due to differences which may exist in the patient profile and the spectrum of clinical activity. The inability of the hospital to determine the presence of important micro-organisms involved in HAI such as MRSA, Vancomycin Resistant Staphylococcus Aureus, Vancomycin Resistant Enterococci and Extended Spectrum Beta-Lactamases. Gram-negative bacteria and fungi limit the comparability of these findings.

Strengths

This study provides an update on HAI rates and also provides insight into infection control status in this major Nigerian hospital. Useful information for benchmarking purposes was provided.

CONCLUSIONS

For the 5 years reviewed HAI rates had been increasing albeit marginally and a downward trend was only observed in 2009, with UTI as a major contributor. HAIs are preventable harms and surveillance has been a key component of the activities to drive down rates of HAI in other countries. It is important that surveillance data are utilized in clinical decision making particularly in the prudent use of urinary catheters to limit the persistent high rates of UTI in this hospital. The use of a more robust surveillance system which is web-enabled can aid access to surveillance data by healthcare providers. Developing national infection control targets and standardized data collection procedures with rigorous performance management would allow for easier evaluation of healthcare systems in the country.