Lack of active SARS-CoV-2 virus in a subset of PCR-positive COVID-19 congregate care patients.

Highly sensitive nucleic acid amplification tests (NAATs) designed to detect SARS-CoV-2 RNA are the standard of care for the diagnosis of COVID-19. However, the accuracy of these methods for the quantitation of active virus rather than non-infectious RNA fragments that can persist for extended periods of time has been unclear. This issue is particularly relevant for congregate care patients who are unable to return to their home residence until fully negative by NAATs. We tested paired samples from individual patients for the presence of virus at both early and later stages of disease. Culture of nasopharyngeal swab samples for 10 days in Vero E6 cells revealed active virus in only 4 out of 14 (28.6%) patients. The ability to isolate viral plaque-forming units (PFU) correlated with viral RNA loads of >6.79 log genomic copies/ml and only occurred in samples collected from patients early after symptom onset and before development of antibody. Culture in Vero E6 cells lacking the STAT1-dependent interferon signaling pathway increased the numbers of viral PFU detected but did not affect the incidence of positive cultures. We conclude that culturable virus is correlated with SARS-CoV-2 NAATs detection only during early symptom onset and with high viral titers/low antibody titers in non-immunosuppressed patients.

Measles investigation: a moving target.

Measles is a highly contagious respiratory infection with significant transmission risk once thought to be on the verge of elimination. Outbreaks in Europe have resulted in resurgence; however, experience with measles is limited in the United States. We describe the impact of 2 measles cases presenting to our emergency department in May 2011. Exposure criteria were defined and revised. Guidance documents were developed and distributed. Suspect cases were masked and escorted to negative pressure. Lack of prompt IgM and polymerase chain reaction testing resulted in delayed disease confirmation. Computerized flagging systems were established. Exposed individuals were screened to determine the need for prophylaxis. Investigation costs were calculated. A total of 171 patients and visitors and 94 employees met exposure criteria. Employees had proof of immunity to measles. Of these, 43 patients and visitors returned for prophylaxis. No subsequent transmission occurred. The conservative cost for these investigations was $63,176.39. Multiple challenges were identified. Inexperience with measles can result in significant outbreaks. Although transmission did occur at another facility, it was prevented at our facility because of rapid case recognition, isolation, health care worker immunity, and multidisciplinary response. Discordance between the Healthcare Infection Control Practices Advisory Committee and public health guidelines for measles control created unnecessary challenges.

The effect of diabetes mellitus on surgical site infections after colorectal and noncolorectal general surgical operations.

Patients undergoing colorectal surgery (CRS) are known to be at increased risk of surgical site infection (SSI). We assessed the effect of diabetes and other risk factors on SSI in patients undergoing CRS and patients undergoing general surgery (GS). American College of Surgeons National Surgical Quality Improvement Program Participant Use Data File from 2005 to 2006 was used. Chi2 tests, t tests, and logistic regression were used to assess the risk factors. Of the 129,909 study patients 10.1 per cent were patients undergoing CRS. The incidence of SSI in patients undergoing CRS was 3.8 times higher (95% CI, 3.6-4.1) than in patients undergoing GS. The incidence of SSI was higher in diabetics than nondiabetics in patients undergoing CRS (15.4 vs. 11.0%, P < 0.001) and patients undergoing GS (5.3 vs. 3.1%, P < 0.001). The significant univariate predictors of SSI for patients undergoing GS and patients undergoing CRS were: males, American Society of Anesthesiologists (ASA) class, diabetes emergency surgery, operation time, and greater than 2 units of intraoperative red blood cell transfusion. For patients undergoing GS, increasing age was also significant. After multivariate adjustment, significant predictors of SSI for patients undergoing GS and patients undergoing CRS were: male gender, diabetes, ASA class, emergency surgery, and operation time. For patients undergoing GS, age also remained significant. Among patients undergoing CRS, insulin-dependent diabetes mellitus (IDDM) and noninsulin-dependent diabetes mellitus (NIDDM) were 1.32 (P < 0.05) times more likely than nondiabetics to develop SSI. Among patients undergoing GS, only IDDM (OR, 1.39; P < 0.001) were at increased risk. In this large hospital-based study, patients undergoing CRS were three times more likely to get SSI than patients undergoing GS. Diabetic patients with CRS (IDDM and NIDDM) and patients undergoing GS (IDDM) were at increased risk of SSI compared with nondiabetics. More intense glycemic control may reduce SSI in patients undergoing CRS with diabetes.