This data identifies the distribution of SSI pathogens and their resistance patterns in 6 adult surgical procedures done over 10 years in multi-hospital healthcare system located in a high income Middle Eastern country. Couple of points should be highlighted while we are interpreting the current findings; this data were collected in the presence of a local guideline for surgical prophylaxis co-developed by members of surgical department and infection control committee. Additionally, surgical bundle of the Institute for Healthcare Improvement (IHI) was implemented throughout the study . Compliance with the guideline and the surgical bundle, however, has varied widely between surgeries and from time to time (data not shown).
Similar to studies done in developed [5, 7, 14, 15] and developing countries [1, 28], the most frequent pathogen in the current study was Staphylococcus aureus, a common skin colonizer. For example, it was approximately 23% in the current study compared with 20% to 30% in these studies [1, 5, 14, 15]. However, GNPs (mainly Pseudomonas spp. and Enterobacteriaceae) were more prevalent in the current study (60%) than seen in developed countries (36%-46%) [5, 7, 14, 15]. This high contribution of GNPs was consistent with several reports from Saudi Arabia [16-18] and developing countries , that showed contribution rates between 55% and 77%. This may be explained by high environmental burden of GNPs, that are usually more resistant to disinfectants compared with GPPs . Additionally, three of the main six surgeries included were abdominal procedures, that have been frequently linked to Enterobacteriaceae and Pseudomonas spp. .
In addition to the low contribution, GPPs causing SSI in the current study was generally less resistant than reported internationally. For example, MRSA rates was 30% in the current study compared with more than 40% in USA [14, 15], Europe , and Asia [31, 32]. In Saudi Arabia, there has been a great variability in the published MRSA rates, probably due to mixing community and hospital isolates as well as clinical and surveillance isolates [33, 34]. Nevertheless, the current finding was consistent with the local MRSA rates obtained from HAI specimens (mainly wound), which ranged between 16% and 57% . For VRE, the current rates (13%) was comparable to recent reports from Saudi Arabia . Additionally, it was comparable to international rates [5, 31], with exception of North and South American ones which traditionally have very high rates of VRE [14, 15, 31]. Despite the relatively low resistance of GPPs observed in the current and local studies, reports has warned from an increasing trend in the resistance of GPPs in Saudi Arabia, specially VRE, probably due to overuse of broad-spectrum antimicrobials and development of new resistance patterns [34, 35].
In addition to higher contribution, GNPs causing SSI in the current study was generally more resistant than reported in US hospitals. For example, all GNPs in the current study (with exception of Enterobacter ) were more resistant than NHSN hospitals, with significant difference in cephalosporin-resistant Klebsiella, MDR Klebsiella, and MDR Escherichia coli [14, 15]. On the other hand, the current rates was even lower than the extremely high rates of cephalosporin and carbapenem resistance among GNPs reported in some developing countries such as Egypt , India , and Iran . The high rate of resistance in GNPs in the current study is probably reflecting a wide range of resistance mechanisms in GNPs observed in our hospitals, such as NDM, OXA 48 and MGrb and outer membrabe protein (OMP) resistance [37-41]. The high rate of resistance in GNPs in the current study is quite alarming as it already increased the mortality by 25%. Additionally, this can be used as a justification for initiation and continuation of broad-spectrum antibiotics, leading to a vicious cycle of enhancing resistance. Consistent with current data, a local study showed that 77% of pathogens isolated from SSI after abdominal surgery were resistant to the prophylactic antibiotic given preoperatively .
With the limited data available locally and regionally, this report can serve as a unique benchmark for caregivers engaged in SSI prophylaxis and antimicrobial stewardship programs. The data were prospectively collected over 10 years by well-trained IPs in 4 hospitals, using the same standard surveillance methodology and the same SSI preventive practices. The relatively large sample size allowed for presenting surgery-specific pathogen distribution and resistance patterns. The use of NHSN resistance definitions allowed for previously unmatched comparisons of resistance patterns between the two differently-matured healthcare systems. Nevertheless, few limitations are acknowledged. The analyzed data were only a sample of a much bigger number of surgeries done in the 4 hospitals during the period covered by the study and almost one-third of SSI were diagnosed clinically. However, these are typical for all studies following the NHSN definitions and NHSN-recommended targeted surveillance methodology. As in other similar studies, underestimation of SSI diagnosis cannot be excluded. However, this should be unlikely, as our population is entitled to free care in our hospitals, which make the likelihood of patients seeking medical care elsewhere is very low. Despite being beyond of the scope of this paper, the lack of extensive data analysis on the colonization rates and the risk factors that can possibly affect the resistance patterns limit the interpretation of the current findings.
In conclusion, Staphylococcus aureus remains the most frequent SSI pathogen, with 30% are MRSA. GNPs are responsible for approximately 60% of SSI and were generally more resistant than seen in Western countries. Resistant GNPs were associated with increased mortality. Making this information available to caregivers and healthcare leaders is critical to secure resources and ensure support in implementing interventions, such as antimicrobial stewardship programs and evidence-based SSI preventive practices [8, 12, 13].