By Carol A. Kemper, MD, FACP

Dr. Kemper reports no financial relationships relevant to this field of study.

Should We Be Looking for ESBL?

SOURCE: Zahar JR, Blot S, Nordmann P, et al. Screening for intestinal carriage of extended-spectrum beta-lactamase-producing Enterobacteriaceae in critically ill patients: Expected benefits and evidence-based controversies. Clin Infect Dis 2019;68:2125-2130.

Prevention strategies are necessary to limit transmission of multidrug-resistant organisms (MDRO) in the hospital, especially in high-risk settings. Identification of carriers of extended-spectrum beta-lactamase (ESBL)-producing organisms via active surveillance, and contact isolation of positives, has been recommended for certain high-risk groups (e.g., ICU).

To thwart transmission of MDRO/extensively drug-resistant organisms (XDRO), our facility implemented routine ESBL surveillance in high-risk individuals in 2015, using perirectal swab specimens and chromogenic agar culture technique. High-risk groups were considered to be admissions from long-term care facilities or an outside facility and patients on hemodialysis. From 2015 to 2017, the prevalence of ESBL carriage steadily increased, up to 14% in patients admitted from skilled nursing facilities (SNF). This meant that many otherwise asymptomatic older SNF patients, who were simply ESBL carriers, now required contact isolation. However, in those who were critically ill or septic, identification of ESBL carriage provided the advantage of preemptively employing the use of a carbapenem as clinically appropriate. One other important advantage to the active surveillance program was that during the three years of surveillance, only one patient was found to have “hospital-onset” ESBL not previously identified on admission. Thus, the program successfully kept the “transmission rates” of MDRO remarkably low.

Ironically, as the prevalence of ESBL colonization in our screening population increased, so did the cost of the program. By 2017, the estimated the annual cost of ESBL surveillance was approximately $250,000 (based on laboratory costs and not the cost of isolation supplies). This was in addition to active surveillance of methicillin-resistant Staphylococcus aureus (MRSA; required by California regulation), Clostridioides difficile, and carbapenem-resistant Enterobacteriaceae (CRE) (recommended by the CDC) in select patients and travelers. The burden to the micro lab was just too much. Thus, in 2017, the infection control team made the difficult decision to abandon ESBL screening. Our disappointment was mollified only by the knowledge that approximately half of such patients required isolation for other reasons (MRSA/C. difficile), since double and triple colonization was not uncommon.

The debate about active ESBL surveillance continues. These authors argued that enforcement of universal precautions and improved hand hygiene makes more sense and ultimately is likely to be a more effective strategy than “search-and isolate,” for the following reasons:

  • The cost of routine active surveillance is not insignificant (as above) and poses a considerable burden to the micro lab; such surveillance costs are not reimbursable by insurance or Medicare.
  • The lag in retrieving results (which may be up to 48-72 hours) means that either individuals being screened must be isolated pending results — or those with ESBL colonization are not isolated initially.
  • The frequency of false-negative surveillance samples may be as high as 25%, depending on technique and detectable levels of fecal colonization.
  • Surveillance focused only on ESBL does not detect other MDRO, such as carbapenem-resistant pseudomonas or MDR-Acinetobacter baumanii — two important hospital pathogens.
  • Defining high-risk groups for screening may overlook those without recognized risk factors (e.g., prior SNF stay or prior travel or residence in Asia or a developing country).
  • Limited studies suggest negligible transmission from asymptomatic carriers of ESBL-containing organisms in the acute care setting.
  • The “human” cost of isolation is not insignificant, from the donning and doffing of gowns and gloves, to the occasional distress of patients being screened with rectal swabs, and then the challenging explanation of why “Grannie is in isolation.” We have had some families so totally overreact that they have prevented contact with the grandchildren.
  • The authors argued that rather than being a useful clinical result, the detection of ESBL in perirectal swabs may contribute to the overuse of carbapenems.
  • The authors argued that ESBL transmission in the critical care setting occurs “rarely” when hand hygiene compliance is maximized. With improved hand hygiene compliance, the authors of one study found little added value to the implementation of contact isolation on acquisition rates of Enterobacteriaceae in the ICU. Further, the use of single rooms and daily chlorhexidine body bathing also may reduce the risk of acquisition of potential pathogens.

The balance in favor of active surveillance for MDRO could shift if more rapid and reliable (and cheaper, less labor-intensive) diagnostic tests were available. But, I wondered, if the risk of transmission of ESBL and other MDRO from asymptomatic individuals with stool carriage is ostensibly so low, as these authors argued, why is such a remarkable increase in ESBL colonization being observed in our local SNF population?

Close the Door to That OR!

SOURCE: Roth JA, Juchler F, Dangel M, et al. Frequent door openings during cardiac surgery are associated with increased risk for surgical site infection: A prospective observational study. Clin Infect Dis 2019;69:290-294.

As the battle for reduction in surgical site infection (SSI) wages (and everyone is pointing fingers at everything and each other), one glaring finding in recent audits of surgical orthopedic and spine cases was the number of times the doors to the OR were opened during the case. For one case alone, we counted 34 internal door openings by surgeons and staff, and that didn’t count the three manufacturer representatives present. Occasionally the door was left open a clear violation of OR policy.

Preliminary studies suggest that OR door openings during surgery may contribute to SSI. Door openings clearly increase the particulate matter in air, and are known to raise bacterial colony counts in the air. From 2016 to 2017, these Swiss authors performed a prospective evaluation of SSI in 688 consecutive cardiac surgery cases, counting the number of times the internal and external OR doors were opened. The doors to two designated ORs were equipped with automated door counters. SSI infection was defined as superficial or deep infection occurring within 30 days of the procedure. (For purposes of defining SSI in the United States, a window of 90 days is required for any procedure with a device, such as a valve.)

During the 17-month study, 688 cardiac surgeries were performed. Twenty-four (3.5%) SSIs occurred within 30 days of the procedure, including one case of mediastinitis, 12 cases of deep sternal infection, and 11 cases of superficial sternal infections. Patients in the non-SSI group were similar in age (approximately 70 years of age) to patients in the SSI group. However, compared with the non-SSI group, the SSI group included more women (24% vs. 41%), the OR times were slightly longer in the SSI group (226 minutes vs. 256 minutes), and procedures included fewer coronary artery bypass grafts (79% vs. 55%) and more valve surgeries (29% vs. 35%) performed in the SSI group. Compared with the non-SSI group, with 17.4 door openings per hour, the SSI group had 19.7 door openings per hour.

A total of 301,594 door openings were logged. Of these, 87,676 occurred between incision and skin closure (that is approximately 127 door openings per case). In both univariate and multivariate analyses, an increased frequency of door openings was associated with an increased risk of SSI (95% confidence interval [CI], 1.11-1.95; P = 0.007). When the analysis was limited to internal door openings only, the risk of SSI was greater (95% CI, 1.24-3.2; P = 0.005). No association with SSI was found with external door openings.

Studies in the United States have raised similar concerns, and there is simply no industry standard. In one study of orthopedic surgeries at Johns Hopkins, the OR door was opened on average every 2.5 minutes, for a total of 10 minutes of open door during an average 90-minute case. Another study of orthopedic surgery in Detroit measured 13.4 open doors per case. In one study, half of door openings were by nursing staff, 24% by anesthesia, and 13% by orthopedist staff. I am told the prime reason for nursing traffic in and out of the OR at our facility is the union requirement for breaks and shift change. We also have observed an increase in manufacturer representatives present, especially with cases requiring complex technical equipment or devices. The question remains, how can OR traffic be limited?