Deactivation of SARS-CoV-2 with pulsed-xenon ultraviolet light: Implications for environmental COVID-19 control.

OBJECTIVES: Prolonged survival of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on environmental surfaces and personal protective equipment may lead to these surfaces transmitting this pathogen to others. We sought to determine the effectiveness of a pulsed-xenon ultraviolet (PX-UV) disinfection system in reducing the load of SARS-CoV-2 on hard surfaces and N95 respirators. METHODS: Chamber slides and N95 respirator material were directly inoculated with SARS-CoV-2 and were exposed to different durations of PX-UV. RESULTS: For hard surfaces, disinfection for 1, 2, and 5 minutes resulted in 3.53 log10, >4.54 log10, and >4.12 log10 reductions in viral load, respectively. For N95 respirators, disinfection for 5 minutes resulted in >4.79 log10 reduction in viral load. PX-UV significantly reduced SARS-CoV-2 on hard surfaces and N95 respirators. CONCLUSION: With the potential to rapidly disinfectant environmental surfaces and N95 respirators, PX-UV devices are a promising technology to reduce environmental and personal protective equipment bioburden and to enhance both healthcare worker and patient safety by reducing the risk of exposure to SARS-CoV-2.

Risk factors and risk adjustment for surgical site infections in pediatric cardiothoracic surgery patients.

BACKGROUND: The complexity of congenital cardiac defects and the aggressive medical management required to support patients through their recovery place children at high risk for surgical site infection (SSI). METHODS: We conducted a retrospective review of children undergoing cardiothoracic surgery at a tertiary care referral center between January 1, 2000, and June 30, 2001. Preoperative, intraoperative, and postoperative data were assessed by multivariate analysis. RESULTS: Of 726 surgical procedures performed in 626 patients, SSIs occurred after 46 procedures performed in 46 patients (6.3%). Infections were superficial (n = 22; 47.8%), deep tissue (n = 7; 15.2%), or organ space (n = 17; 37.0%), including 5 episodes of mediastinitis. Median time to SSI was 10 days; 36% of the infections were identified after discharge. On multivariate analysis, children with SSIs were more likely to have been <30 days old (odds ratio [OR], 2.9; 95% confidence interval [CI], 1.2-70), to have a perioperative medical device, and to use parenteral nutrition (OR, 3.3; 95% CI, 1.4-7.9). Multiple severity of illness scores, the Risk Adjustment for Congenital Heart Surgery (RACHS-1) category, and longer duration of postoperative antimicrobials were not associated with SSI. CONCLUSION: The use of perioperative medical interventions increases the risk of SSI in young children after cardiac surgery. Prolonged postoperative courses of antimicrobials should be avoided in the absence of documented infection.

Health care-associated bloodstream infections associated with negative- or positive-pressure or displacement mechanical valve needleless connectors.

BACKGROUND: Health care-associated, central venous catheter-related bloodstream infections (HA-BSIs) are a major cause of morbidity and mortality. Needleless connectors (NCs) are an important component of the intravenous system. NCs initially were introduced to reduce health care worker needlestick injuries, yet some of these NCs may increase HA-BSI risk. METHODS: We compared HA-BSI rates on wards or intensive care units (ICUs) at 5 hospitals that had converted from split septum (SS) connectors or needles to mechanical valve needleless connectors (MV-NCs). The hospitals (16 ICUs, 1 entire hospital, and 1 oncology unit; 3 hospitals were located in the United States, and 2 were located in Australia) had conducted HA-BSI surveillance using Centers for Disease Control and Prevention definitions during use of both NCs. HA-BSI rates and prevention practices were compared during the pre-MV period, MV period, and post-MV period. RESULTS: The HA-BSI rate increased in all ICUs and wards when SS-NCs were replaced by MV-NCs. In the 16 ICUs, the HA-BSI rate increased significantly when SS-NCs or needles were replaced by MV-NCs (6.15 vs 9.49 BSIs per 1000 central venous catheter [CVC]-days; relative risk, 1.54; 95% confidence interval, 1.37-1.74; P < .001). The 14 ICUs that switched back to SS-NCs had significant reductions in their BSI rates (9.49 vs 5.77 BSIs per 1000 CVC-days; relative risk, 1.65; 95% confidence interval, 1.38-1.96; p < .001). BSI infection prevention strategies were similar in the pre-MV and MV periods. CONCLUSIONS: We found strong evidence that MV-NCs were associated with increased HA-BSI rates, despite similar BSI surveillance, definitions, and prevention strategies. Hospital personnel should monitor their HA-BSI rates and, if they are elevated, examine the role of newer technologies, such as MV-NCs.

Gram-negative bloodstream infections in hematopoietic stem cell transplant patients: the roles of needleless device use, bathing practices, and catheter care.

BACKGROUND: Between August 1 and October 30, 1998 (outbreak period), an increased incidence of central venous catheter (CVC)-associated gram-negative bacterial bloodstream infection (GN-BSI) was detected in hematopoietic stem cell transplantation (HSCT) candidates and recipients in an outpatient HSCT unit. The objectives of the present study were to determine strategies for controlling the outbreak and identify risk factors for GN-BSI. METHODS: Two case-control studies, an assessment of infection control practices, microbiologic studies, and water quality analysis were conducted. A case was defined as any outpatient with a CVC and a primary GN-BSI during the outbreak period. RESULTS: All of the 31 case patients identified had needleless intravenous (IV) access devices. Independent risk factors for CVC-associated GN-BSI were self-administered IV infusion (odds ratio [OR] = 6.2; P = .02), lower frequency of needleless device changes (OR = 15.2; P = .03), and more frequent baths (OR = 1.4; P = .05). Interventions included increased frequency of needleless device change, recommending showers rather than baths, and use of CVC protection during showering/bathing. After these interventions, the CVC-associated GN-BSI rate declined to below the preoutbreak period rate (2.1/1000 vs 0.3/1000 CVC-days; P < .01). CONCLUSIONS: This study demonstrated an increased risk of CVC-associated GN-BSIs related to self-IV infusion, bathing habits, and frequency of needleless device change. Infection control practices associated with the use of needleless devices may expose susceptible patients to increased risk for BSI.

Reprocessing and reuse of single-use medical devices used during hemodynamic procedures in Brazil: a widespread and largely overlooked problem.

BACKGROUND: Several medical devices used during hemodynamic procedures, particularly angiographic diagnostic and therapeutic cardiac catheters, are manufactured for single use only. However, reprocessing and reuse of these devices has been reported, to determine the frequency of reuse and reprocessing of single-use medical devices used during hemodynamic procedures in Brazil and to evaluate how reprocessing is performed. DESIGN: National survey, conducted from December 1999 to July 2001. METHODS: Most of the institutions affiliated with the Brazilian Society of Hemodynamic and Interventional Cardiology were surveyed by use of a questionnaire sent in the mail. RESULTS: The questionnaire response rate was 50% (119 of 240 institutions). Of the 119 institutions that responded, 116 (97%) reported reuse of single-use devices used during hemodynamic procedures, and only 26 (22%) reported use of a standardized reprocessing protocol. Cleaning, flushing, rinsing, drying, sterilizing and packaging methods varied greatly and were mostly inadequate. Criteria for discarding reused devices varied widely. Of the 119 institutions that responded, 80 (67%) reported having a surveillance system for adverse events associated with the reuse of medical devices, although most of these institutions did not routinely review the data, and only 38 (32%) described a training program for the personnel who reprocessed single-use devices. CONCLUSIONS: The reuse of single-use devices used during hemodynamic procedures was very frequent in hospitals in Brazil. Basic guidance on how to reuse and reprocess single-use medical devices is urgently needed, because, despite the lack of studies to support reusing and reprocessing single-use medical devices, such devices are necessary in limited-resource areas in which these practices are current.

Saline-filled breast implant contamination with Curvularia species among women who underwent cosmetic breast augmentation.

BACKGROUND: During December 2000-July 2001, black sediment was noted in saline-filled silicone breast implants of women who had undergone revision surgery at facility A. Curvularia fungus was isolated from implant saline. METHODS: To identify risk factors for contamination with Curvularia species, we performed case-control, retrospective cohort, and laboratory studies and conducted procedural reviews. A case patient was defined as any woman who underwent revision surgery at facility A between January 2000 and June 2001 and had black sediment in her implants. RESULTS: Five patients met the case definition. Contamination was associated with having had surgery performed in operating room (OR) 2 (4/88 vs. 1/140; P=.07) and a longer duration of surgery (P<.001). A longer duration spent in the OR was an additional risk factor (P=.005). Curvularia fungus was isolated from the sterile supply room, where saline bottles had been stored under a water-damaged ceiling, and from the corridor outside OR 2; it was also found more commonly from facility A personnel than from non-facility A personnel (12/34 vs. 4/60; P<.001). Saline was warmed in a cabinet opposite OR 2, which was maintained at negative pressure differentials, then was poured into bowls open to the OR 2 environment before injection into implants. CONCLUSION: Surgeons should always use closed systems to inflate breast implants. Surgery center infection control measures must include moisture control and balanced ventilation systems.

Improving influenza immunization rates among healthcare workers caring for high-risk pediatric patients.

OBJECTIVE: To assess influenza vaccination rates of healthcare workers (HCWs) in neonatal intensive care units (NICUs), pediatric intensive care units (PICUs), and oncology units in Pediatric Prevention Network (PPN) hospitals. PARTICIPANTS: Infection control practitioners and HCWs in NICUs, PICUs, and oncology units. METHODS: In November 2000, posters, electronic copies of a slide presentation, and an influenza fact sheet were distributed to 32 of 76 PPN hospitals. In January 2001, a survey was distributed to PPN hospital participants to obtain information about the immunization campaigns. On February 7, 2001, a survey of influenza immunization was conducted among HCWs in NICU, PICU, and oncology units at participating hospitals. RESULTS: Infection control practitioners from 19 (25%) of the 76 PPN hospitals completed the surveys. The median influenza immunization rate was 43% (range, 12% to 63%), with 7 hospitals exceeding 50%. HCWs (n = 1123) at 15 PPN hospitals completed a survey; 53% of HCWs reported receiving influenza immunization. Immunization rates varied by work site: 52% in NICUs and PICUs compared with 60% in oncology units. Mobile carts and PPN educational fact cards were associated with higher rates among these subpopulations (P < .001) (361 [63%] of 575 vs 236 [44%] of 541 for mobile carts; 378 [60%] of 633 vs 219 [45%] of 483 for fact cards). CONCLUSION: Despite delayed distribution of influenza vaccine during the 2000-2001 season, immunization rates at 7 hospitals and among HCWs in high-risk units exceeded the National Association of Children's Hospitals and Related Institutions goal of 50%.

Clostridium infections associated with musculoskeletal-tissue allografts.

BACKGROUND: Allografts are commonly used in orthopedic reconstructive surgery. In 2001, approximately 875,000 musculoskeletal allografts were distributed by U.S. tissue banks. After the death from Clostridium sordellii sepsis of a 23-year-old man who had received a contaminated allograft from a tissue bank (Tissue Bank A), the Centers for Disease Control and Prevention initiated an investigation, including enhanced case finding, of the methods used for the recovery, processing, and testing of tissue. METHODS: A case of allograft-associated clostridium infection was defined as a culture-proven infection of a surgical site within one year after allograft implantation, from January 1998 to March 2002. We traced tissues to tissue banks that recovered and processed these tissues. We also estimated the rates of and risk ratios for clostridium infections for tissues processed by the implicated tissue bank and reviewed processing and testing methods used by various tissue banks. RESULTS: Fourteen patients were identified, all of whom had received allografts processed by Tissue Bank A. The rates of clostridium infection were 0.12 percent among patients who received sports-medicine tissues (i.e., tendons, femoral condyles, menisci) from Tissue Bank A and 0.36 percent among those who received femoral condyles in particular. The risk-ratio estimates for clostridium infections from tissues processed by Tissue Bank A, as compared with those from other tissue banks, were infinite (P<0.001) for musculoskeletal allografts, sports-medicine tissues, or tendons. Because Tissue Bank A cultured tissues only after treating them with a nonsporicidal antimicrobial solution, some test results were probably false negatives. Tissues from implicated donors were released despite the isolation of clostridium or bowel flora from other anatomical sites or reports of infections in other recipients. CONCLUSIONS: Clostridium infections were traced to allograft implantation. We provide interim recommendations to enhance tissue-transplantation safety. Tissue banks should validate processes and culture methods. Sterilization methods that do not adversely affect the functioning of transplanted tissue are needed to prevent allograft-related infections.

Secular trends in hospital-acquired Clostridium difficile disease in the United States, 1987-2001.

We reviewed Clostridium difficile-associated disease (CDAD) data from the intensive care unit (ICU) and hospital-wide surveillance components of the National Nosocomial Infections Surveillance System hospitals during 1987-2001. ICU CDAD rates increased significantly only in hospitals with >500 beds (P<.01) and correlated with the duration of ICU stay (r=0.82; P<.05). Hospital-wide (non-ICU) rates increased only in hospitals with <250 beds (P<.01) and in general medicine patients versus surgery patients (P<.0001). CDAD predominated in general hospitals versus other facility types, and rates were significantly higher during winter versus nonwinter months (P<.01). Thus, prevention efforts should be targeted to high-risk groups in these settings.

Vancomycin use in hospitalized pediatric patients.

OBJECTIVES: To assess vancomycin utilization at children's hospitals, to determine risk factors for vancomycin use and length of therapy, and to facilitate adapting recommendations to optimize vancomycin prescribing practices in pediatric patients. METHODS: Two surveys were conducted at Pediatric Prevention Network hospitals. The first (Survey I) evaluated vancomycin control programs. The second (Survey II) prospectively reviewed individual patient records. Each hospital was asked to complete questionnaires on 25 consecutive patients or all patients for whom vancomycin was prescribed during a 1-month period. RESULTS: In Survey I, 55 of 65 (85%) hospitals reported their vancomycin control policies. Three quarters had specific policies in place to restrict vancomycin use. One half had at least 3 vancomycin restriction measures. In Survey II, personnel at 22 hospitals reviewed 416 vancomycin courses, with 2 to 25 (median = 12) patients tracked per hospital. Eighty-two percent of the vancomycin prescribed was for treatment of neonatal sepsis, fever/neutropenia, fever of unknown origin, positive blood culture, pneumonia, or meningitis. In an additional 6% (26/416), vancomycin was prescribed for patients with beta-lactam allergies and in 13% (56/416) for prophylaxis. Median duration of prophylaxis was 2 days (range: 1-15 days). Almost half (196, 47%) of the patients who received vancomycin were in intensive care units; 27% of the vancomycin courses were initiated by neonatologists and 19% by hematologists/oncologists. The predominant risk factor at the time of vancomycin initiation was the presence of vascular catheters (322, 77%); other host factors included cancer chemotherapy (55, 13%), transplant (30, 7%), shock (24, 6%), other immunosuppressant therapy (17, 4%), or hyposplenic state (2, <1%). Other clinical considerations were severity of illness (96, 23%), uncertainty about diagnosis (51, 12%), patient not responding to current antibiotic therapy (40, 10%), or implant infection (13, 3%). When vancomycin was initiated, blood cultures were positive in 85 patients (20%); cultures from other sites were positive in 45 (11%), and Gram stains of body fluids were positive in 37 (9%). In 29 (7%) patients, organisms sensitive only to vancomycin were isolated before vancomycin initiation. Reasons for discontinuing vancomycin included: therapeutic course completed (125, 30%), negative cultures (106, 25%), alternative antibiotics initiated (75, 18%), illness resolved (14, 3%), or patient expired (13, 3%). Final results of blood culture isolates resistant to beta-lactam antibiotics included 48 coagulase-negative staphylococcus, 5 Staphylococcus aureus, and 10 other species. CONCLUSIONS: At children's hospitals, vancomycin is initiated for therapy in patients who have vascular catheters and compromised host factors. Only 7% had laboratory-confirmed beta-lactam-resistant organisms isolated at the time vancomycin was prescribed. Efforts to modify empiric vancomycin use in children's hospitals should be targeted at intensivists, neonatologists, and hematologists. Initiatives to decrease length of therapy by decreasing the number of surgical prophylaxis doses and days of therapy before laboratory results may decrease vancomycin exposure.

Risk factors for Burkholderia cepacia complex colonization and infection among patients with cystic fibrosis.

OBJECTIVES: To determine risk factors for acquiring Burkholderia cepacia complex among patients with cystic fibrosis (CF). STUDY DESIGN: A case-control study was conducted with active surveillance for B cepacia complex colonization/infection among patients at 21 CF centers from April 1986 to March 1989 (study period). A case-patient was defined as any CF patient with B cepacia complex colonization for the first time during the study period. Control patients were patients with CF not B cepacia complex colonized during the study period. For each patient, a questionnaire was completed semiannually. RESULTS: In multivariate analyses, hospitalization for pulmonary exacerbations, living with a B cepacia complex-positive person, attending a CF summer camp, and direct contact with a B cepacia complex-colonized CF person outside of camp and home were associated with B cepacia complex acquisition. Receiving antimicrobial aerosol therapy or cleaning and drying a home-used nebulizer between uses were associated with a decrease in B cepacia complex acquisition. CONCLUSIONS: Numerous factors inside and outside the health care setting are associated with person-to-person transmission of B cepacia complex among patients with CF. Prevention programs should reduce direct or indirect contact between noncolonized and B cepacia complex-colonized/infected patients with CF.

Clinical and immune impact of Mycobacterium bovis BCG vaccination scarring.

The World Health Organization recommends Mycobacterium bovis BCG vaccination in areas of high tuberculosis prevalence. BCG's clinical and immune effects, not necessarily Mycobacterium tuberculosis specific, are unclear. BCG vaccine scarring often is used as a surrogate marker of vaccination or of effective vaccination. We evaluated BCG scarring status in relation to clinical findings and outcome in 700 hospitalized Malawians, of whom 32 had M. tuberculosis bloodstream infections (BSI) (10 of whom had cellular immune studies done) and of whom 48 were infants <6 months old and therefore recently vaccinated (19 of whom had immune studies). In the patients >/=6 months old, scarring was not related to the presence of pulmonary symptoms (35 versus 30%), chronic cough or fever, mortality, or M. tuberculosis BSI. In M. tuberculosis BSI patients, scarring was unrelated to mortality, vital signs, or clinical symptoms but those with scarring had higher proportions of memory and activated T cells and more type 2-skewed cytokine profiles. Infants with either BCG scarring (n = 10) or BCG lesional inflammation (n = 5) had no symptoms of sepsis, but 18 of 33 infants without BCG vaccination lesions did. Those with BCG lesions had localized infections more often than did those without BCG lesions. These infants also had lower median percentages of lymphocytes spontaneously making interleukin-4 (IL-4) or tumor necrosis factor alpha (TNF-alpha) and lower ratios of T cells spontaneously making IL-4 to T cells making IL-6. Thus, we found that, in older patients, BCG vaccine scarring was not associated with M. tuberculosis-specific or nonspecific clinical protection. Those with M. tuberculosis BSI and scarring had immune findings suggesting previous M. tuberculosis antigen exposure and induction of a type 2 cytokine pattern with acute reexposure. It is unlikely that this type 2 pattern would be protective against mycobacteria, which require a type 1 response for effective containment. In infants <6 months old, recent BCG vaccination was associated with a non-M. tuberculosis-specific, anti-inflammatory cytokine profile. That the vaccinated infants had a greater frequency of localized infections and lesser frequency of sepsis symptoms suggests that this postvaccination cytokine pattern may provide some non-M. tuberculosis-specific clinical benefits.

Spontaneous cytokine production and its effect on induced production.

Cytokines regulate cellular immune activity and are produced by a variety of cells, especially lymphocytes, monocytes, and macrophages. Multiparameter flow cytometry is often used to examine cell-specific cytokine production after in vitro phorbol 12-myristate 13-acetate and ionomycin induction, with brefeldin A or other agents added to inhibit protein secretion. Spontaneous ex vivo production reportedly rarely occurs. We examined the spontaneous production of interleukin 2 (IL-2), IL-4, IL-6, IL-8, IL-10, tumor necrosis factor alpha (TNF-alpha), and gamma interferon (IFN-gamma) by peripheral-blood B lymphocytes, T cells, CD8(-) T cells, CD8(+) T cells, CD3(-) CD16/56(+) lymphocytes (natural killer [NK] cells), CD3(+) CD16/56(+) lymphocytes (natural T [NT] cells), and/or monocytes of 316 acutely ill hospitalized persons and 62 healthy adults in Malawi, Africa. We also evaluated the relationship between spontaneous and induced cytokine production. In patients, spontaneous TNF-alpha production occurred most frequently, followed in descending order by IFN-gamma, IL-8, IL-4, IL-10, IL-6, and IL-2. Various cells of 60 patients spontaneously produced TNF-alpha; for 12 of these patients, TNF-alpha was the only cytokine produced spontaneously. Spontaneous cytokine production was most frequent in the immunoregulatory cells, NK and NT. For IL-2, IL-4, IL-6, IL-8, and IL-10, spontaneous cytokine production was associated with greater induced production. For TNF-alpha and IFN-gamma, the relationships varied by cell type. For healthy adults, IL-6 was the cytokine most often produced spontaneously. Spontaneous cytokine production was not unusual in these acutely ill and healthy persons living in an area where human immunodeficiency virus, mycobacterial, malaria, and assorted parasitic infections are endemic. In such populations, spontaneous, as well as induced, cell-specific cytokine production should be measured and evaluated in relation to various disease states.

Prevalence of surgical-site infections and patterns of antimicrobial use in a large tertiary-care hospital in Ho Chi Minh City, Vietnam.

BACKGROUND: Few studies have been conducted in Vietnam on the epidemiology of healthcare-associated infections or antimicrobial use. Thus, we sought to determine the prevalence of and risk factors for surgical-site infections (SSIs) and to document antimicrobial use in surgical patients in a large healthcare facility in Vietnam. METHODS: We conducted a point-prevalence survey of SSIs and antimicrobial use at Cho Ray Hospital, Ho Chi Minh City, a 1,250-bed inpatient facility. All patients on the 11 surgical wards and 2 intensive care units who had surgery within 30 days before the survey date were included. RESULTS: Of 391 surgical patients, 56 (14.3%) had an SSI. When we compared patients with and without SSIs, factors associated with infection included trauma (relative risk [RR], 2.65; 95% confidence interval [CI95], 1.60 to 4.37; P < .001), emergency surgery (RR, 2.74; CI95, 1.65 to 4.55; P < .001), and dirty wounds (RR, 3.77; CI95, 2.39 to 5.96; P < .001). Overall, 198 (51%) of the patients received antimicrobials more than 8 hours before surgery and 390 (99.7%) received them after surgery. Commonly used antimicrobials included third-generation cephalosporins and aminoglycosides. Thirty isolates were identified from 26 SSI patient cultures; of the 25 isolates undergoing antimicrobial susceptibility testing, 22 (88%) were resistant to ceftriaxone and 24 (92%) to gentamicin. CONCLUSIONS: Our data show that (1) SSIs are prevalent at Cho Ray Hospital; (2) antimicrobial use among surgical patients is widespread and inconsistent with published guidelines; and (3) pathogens often are resistant to commonly used antimicrobials. SSI prevention interventions, including appropriate use of antimicrobials, are needed in this population.

Bloodstream infections in pediatric oncology outpatients: a new healthcare systems challenge.

OBJECTIVE: To investigate a perceived increase in central venous catheter (CVC)-associated bloodstream infections (BSIs) among pediatric hematology-oncology outpatients. DESIGN: A case-control study. SETTING: A pediatric hematology-oncology outpatient clinic at Fresno Children's Hospital. PATIENTS: Pediatric hematology-oncology clinic outpatients with CVCs at Fresno Children's Hospital between November 1994 and October 1997. METHODS: A case-patient was defined as any hematology-oncology outpatient with a CVC-associated BSI at Fresno Children's Hospital from November 1996 to October 1997 (study period) without a localizable infection. To identify case-patients, we reviewed Fresno Children's Hospital records for all hematology-oncology clinic patients, those with CVCs and those with CVCs and BSIs. Control-patients were randomly selected hematology-oncology outpatients with a CVC but no BSI during the study period. Case-patient and control-patient demographics, diagnoses, caretakers, catheter types, catheter care, and water exposure were compared. RESULTS: Twenty-five case-patients had 42 CVC-associated BSIs during the study period. No significant increase in CVC-associated BSI rates occurred among pediatric hematology-oncology patients. However, there was a statistically significant increase in nonendogenous, gram-negative (eg, Pseudomonas species) BSIs during summer months (May-October) compared with the rest of the year. Case-patients and control-patients differed only in catheter type; case-patients were more likely than control-patients to have a transcutaneous CVC. Summertime recreational water exposures were similar and high in the two groups. CONCLUSIONS: Hematology-oncology clinic patients with transcutaneous CVCs are at greater risk for CVC-associated BSI, particularly during the summer. Caretakers should be instructed on proper care of CVCs, particularly protection of CVCs during bathing and recreational summer water activities, to reduce the risk of nonendogenous, gram-negative BSIs.

Vitamin A levels and immunity in humans.

In animal studies, vitamin A deficiency induces a shift from type 2 (humoral) to type 1 (cellular) cytokines; there are no similar data for humans. Control of human immunodeficiency virus (HIV) and Mycobacterium tuberculosis infections requires type 1 cytokine (cellular) immunity. These infections and vitamin A deficiency are highly prevalent in Africa. We therefore examined the interactions among serum vitamin A levels, immune parameters, HIV infection status, Mycobacterium bovis BCG vaccine scarring (as an indicator of a type 1 cytokine profile), and clinical findings for 70 hospitalized children in Malawi, Africa. Directly conjugated monoclonal antibodies and flow cytometry were used to assess cell-specific cytokine production by peripheral blood monocytes and lymphocyte subpopulations. The statistical techniques employed included nonparametric statistics and logistic regression analyses. Thirty percent of the participants had severe vitamin A deficiency (<10 microg/dl), 34% had moderate deficiency (10 to <20 microg/dl), and 36% had normal levels (> or = 20 microg/dl). Vitamin A levels were lower for HIV-positive than for HIV-negative children (median, 10 and 17 microg/dl, respectively). Vitamin A-deficient children (<20 microg/dl) were more likely than non-vitamin A-deficient children to have higher proportions of natural killer (NK) cells (median, 8.3 and 5.2%, respectively) and lower ratios of interleukin-10-producing monocytes to tumor necrosis factor alpha-producing monocytes after induction (median, 1.0 and 2.3, respectively). Vitamin A-deficient children were also more likely than non-vitamin A-deficient children to exhibit respiratory symptoms (47% versus 12%) and visible BCG vaccine scars (83% versus 48%), which are indicative of a type 1 response to vaccination. Vitamin A status did not vary with gender, age, incidence of malaria parasitemia, blood culture positivity, or rates of mortality (6% of vitamin A-deficient children died versus 20% of non-vitamin A-deficient children). Lower vitamin A levels were associated with a relative type 1 cytokine dominance and proportionately more NK cells, both of which may be somewhat beneficial to persons who are exposed to HIV, M. tuberculosis, or other type 1 pathogens.

Demographic and immune correlates of human herpesvirus 8 seropositivity in Malawi, Africa.

BACKGROUND: In the USA, human herpesvirus 8 (HHV-8) is associated with Kaposi's sarcoma (KS) and HIV infection. We examined HHV-8 seroprevalence in a Malawian cohort, and assessed its relationship with HIV, KS, demographic characteristics, and immune findings. METHODS: In 1997 and 1998, blood samples were obtained from 272 hospitalized Malawian patients, for whom demographic information was obtained, and 24 healthy volunteers without demographic data. We used enzyme immunoassays to assess seroprevalence and antibody titers to peptide antigens derived from HHV-8 K8.1 and ORF65-encoded proteins. Intracellular cytokines and cell surface antigens were assessed with four-color flow cytometry. Data were analyzed using non-parametric univariate and regression analytic techniques. RESULTS: The rates of HHV-8 seroprevalence to either or both HHV-8 peptides were 67% for the patients and 54% for the healthy volunteers. Seroprevalence increased with patients' age (P<0.001) but was not associated with HIV status, percentage of lymphocytes expressing CD4, or KS (n=10). Seropositive females had lower antibody titers to both peptides than did males (medians: 455 versus 1361 for K8.1, P<0.001; and 268 versus 405 for ORF65, P=0.044). For the healthy volunteers, the percentage of CD8+ cells producing IFN-gamma after stimulation was significantly lower in ORF65-specific antibody-positive persons (medians: 24% versus 57%, P=0.008). CONCLUSIONS: In Malawi, HHV-8 is endemic and is not associated with HIV infection or HIV severity. Seroprevalence rates increase in childhood, and, most steeply in adolescence. Titers are higher in seropositive males than in sero-positive females. The immune effects of HHV-8 in healthy adults are consistent with chronic inhibition of type 1 cytotoxic T-cell responsiveness, independent of HIV status.