Cutaneous Colonization Research Articles

Staphylococcus aureus nasal carriage in patients on haemodialysis: role of cutaneous colonization

We performed a prospective study of Staphylococcus aureus nasal carriage in patients on chronic haemodialysis to determine the role of cutaneous colonization in the aetiology of recurrent nasal colonization. From February 2000 to September 2001, 71 patients on chronic haemodialysis in the dialysis unit at a university hospital were screened monthly for S. aureus nasal carriage. Carriers received nasal mupirocin for five days and were tested for nasal and cutaneous carriage two days later and monthly thereafter. Using genotyping results, recurrence was defined as relapse if pretreatment and subsequent nasal isolates were clonally identical; if the isolates were different, it was considered recolonization. Thirty-nine patients (55%) were nasal carriers: 11 initially and 28 during follow-up. Among the mupirocin-treated patients, the eradication of S. aureus nasal carriage rate was 88.5%. Nasal recurrence was documented in 17 patients (43.5%), and S. aureus nasal strains were available for molecular typing in 14 patients with a total of 23 recurrence episodes. On the basis of pulsed-field gel electrophoresis analysis, 16 (70%) recurrence episodes were considered relapses and seven were considered (30%) recolonizations. Among the episodes of relapse, prior cutaneous colonization was detected in only three cases. In haemodialysis patients, the majority of nasal carriage recurrences after mupirocin therapy were due to relapses. Cutaneous colonization does not appear to be relevant in the development of these relapses.

Paradoxical Exacerbation of Psoriasis in AIDS: Proposed Explanations Including the Potential Roles of Substance P and Gram-negative Bacteria

Psoriasis, a TH1-induced disorder, is not more common in human immunodeficiency virus (HIV) infection than in the general population. However, it may appear for the first time or pre-existing psoriasis may worsen and be difficult to treat in HIV disease. The paradoxical exacerbation of psoriasis in AIDS has not been fully explained. Various explanations have been proposed including (a) the reduction of Langerhans' cells (LCs) in HIV disease, (b) the direct epidermal proliferative effect of HIV, (c) the altered cytokine profile in HIV disease, (d) HIV-induced macrophage nitric oxide (NO) production, (e) the increased CD8/CD4 T-cell ratio in HIV infection and (f) the increased colonization of skin by Staphylococcus aureus. However, the observations that (a) LCs cells play an important role in the pathogenesis of psoriasis and a variety of topical and systemic psoriasis treatments cause a reversible decrease in LC function, (b) psoriasis may improve in end-stage HIV infection, (c) overproduction of some TH2 cytokines and underproduction of IL-2 in HIV infection, and (d) the presence of NO favors a TH2 response over a TH1 response make the first four explanations difficult to interpret. Since psoriasis is exacerbated in HIV infection possibly due to the increased staphylococcal colonization, and psoriatic keratinocytes could aggravate HIV infection through production of TNF-α, it could be reasoned that in HIV-positive psoriatics a strong vicious cycle is present between the degree of immune deficiency and the staphylococcal colonization, explaining the poor prognosis of both AIDS and psoriasis in these patients.With reference to the studies which indicate significant involvement of substance P (SP) in the pathogenesis of psoriasis and on the other hand increased release of this agent by HIV-infected immune cells it is proposed that SP plays an important role in creating the paradox. Since in HIV-positive psoriatics the source of SP is largely immune cells not neurons, capsaicin, which exerts its action selectively on a subpopulation of neurons, could not be of significant therapeutic value. As SP significantly enhances HIV-1 replication in latently infected immune cells, psoriatic lesions, being heavily infiltrated with immune cells and having high concentrations of SP, could serve as high HIV-replication foci, with the resultant rapid progression of the infection towards AIDS.Additionally, given that lipopolysaccharide is supposed to exacerbate psoriasis, increase of Gram-negative infections or cutaneous colonization with these organisms in AIDS may partly explain the paradox.Understanding the HIV-induced immunodysregulation that is associated with psoriasis in some HIV-seropositive patients may assist in the delineation of the immunopathogenesis of the disease in HIV-seronegative psoriatics.

The pathogenesis of catheter-related bloodstream infection with noncuffed short-term central venous catheters.

Short-term, noncuffed, percutaneously inserted central venous catheters (CVCs) are widely used and cause more than 250,000 bloodstream infections (BSIs) in hospitals each year in the United States. We report a prospective study undertaken to determine the pathogenesis of CVC-related BSI. Prospective cohort study in a university hospital 24-bed medical-surgical intensive care unit. Patients participating in two randomized trials during 1998-2000-one studying the efficacy of a 1% chlorhexidine-75% alcohol solution for cutaneous antisepsis and the other a novel chlorhexidine-impregnated sponge dressing-formed the study population; CVC-related BSIs were considered to be extraluminally acquired if concordance was identified solely between isolates from catheter segments, skin, and blood cultures and intraluminally acquired if concordance was demonstrated only between hub or infusate and blood culture isolates, as confirmed by DNA subtyping of isolates from blood and catheter sites or infusate. Of 1,263 catheters (6075 CVC days) prospectively studied, 35 (2.7%) caused BSI (5.9 per 1000 CVC days); 27 were caused by coagulase-negative staphylococci. Overall, 45% of infections were extraluminally acquired, 26% were intraluminally derived, and the mechanism of infection was indeterminate in 29%. In the pooled control groups of the two trials, 25 CVC-related BSIs occurred (7.0 per 1000 CVC days), of which 60% of infections were extraluminally acquired, 12% were intraluminally derived and 28% were indeterminate. In contrast, CVC-related BSIs in the treatment groups were most often intraluminally derived (60%, p=0.006). Most catheter-related BSIs with short-term percutaneously inserted, noncuffed CVCs were extraluminally acquired and derived from the cutaneous microflora. Strategies achieving successful suppression of cutaneous colonization can substantially reduce the risk of catheter-related BSI with short-term CVCs.

Framing the Future of Antifungals in Atopic Dermatitis

Atopic dermatitis (AD) is a frequent chronic inflammatory skin disease. Some fungal colonization or infection of the skin may exacerbate AD severity, particularly the so-called head and neck variant. In addition, excessive intestinal colonization by Candida albicans may represent an additional triggering factor. Hence, there is a rationale to use antifungals in selected AD patients. Early trials with topical ketoconazole in head and neck AD showed a decrease in Malassezia colonization, but no significant improvement was observed in the clinical severity. In contrast, clinical improvement and decreased serum IgE were obtained in patients with positive Malassezia radioallergosorbent tests (RASTs) who were treated by oral ketoconazole. Some preliminary data suggested that oral itraconazole treatment in AD patients reduced the need for topical corticosteroids, provided clinical improvement particularly in head and neck AD, reduced the cutaneous and intestinal fungal colonization that may trigger AD, reduced the percentage of positive Malassezia cultures and demonstrated a decrease in C. albicans and Malassezia RAST values. Furthermore, beside its antifungal action, itraconazole in part relieves pruritus and inflammation. In conclusion, oral itraconazole treatment can alleviate AD severity in selected patients. Fluconazole is also effective. Further research is warranted to identify whether the load in skin surface fungal agents, the fungal RAST values and specific prick testing should be assessed in order to optimize the antifungal management in AD patients.

New yeast species, Malassezia dermatis, isolated from patients with atopic dermatitis.

Malassezia species are considered to be one of the exacerbating factors in atopic dermatitis (AD). During examination of the cutaneous colonization of Malassezia species in AD patients, we found a new species on the surface of the patients' skin. Analysis of ribosomal DNA sequences suggested that the isolates belonged to the genus MALASSEZIA: They did not grow in Sabouraud dextrose agar but utilized specific concentrations of Tween 20, 40, 60, and 80 as a lipid source. Thus, we concluded that our isolates were new members of the genus Malassezia and propose the name Malassezia dermatis sp. nov. for these isolates.

Molecular analysis of Malassezia microflora on the skin of atopic dermatitis patients and healthy subjects.

Members of the genus Malassezia, lipophilic yeasts, are considered to be one of the exacerbating factors in atopic dermatitis (AD). We examined variation in cutaneous colonization by Malassezia species in AD patients and compared it with variation in healthy subjects. Samples were collected by applying transparent dressings to the skin lesions of AD patients. DNA was extracted directly from the dressings and amplified in a specific nested PCR assay. Malassezia-specific DNA was detected in all samples obtained from 32 AD patients. In particular, Malassezia globosa and M. restricta were detected in approximately 90% of the AD patients and M. furfur and M. sympodialis were detected in approximately 40% of the cases. The detection rate was not dependent on the type of skin lesion. In healthy subjects, Malassezia DNA was detected in 78% of the samples, among which M. globosa, M. restricta, and M. sympodialis were detected at frequencies ranging from 44 to 61%, with M. furfur at 11%. The diversity of Malassezia species found in AD patients was greater (2.7 species detected in each individual) than that found in healthy subjects (1.8 species per individual). Our results suggest that M. furfur, M. globosa, M. restricta, and M. sympodialis are common inhabitants of the skin of both AD patients and healthy subjects, while the skin microflora of AD patients shows more diversity than that of healthy subjects. To our knowledge, this is the first report of the use of a nested PCR as an alternative to fungal culture for analysis of the distribution of cutaneous Malassezia spp.

Molecular analysis of malassezia microflora on the skin of atopic dermatitis patients and healthy subjects

We compared cutaneous colonization levels of Malassezia species in patients with AD and healthy subjects using nested PCR. Malassezia-specific DNA was detected in all 32 of the patients with AD. M. globosa and M. restricta were detected in approximately 90% of these patients, with M. furfur and M. sympodialis being detected in approximately 40% of the cases. In healthy subjects, Malassezia DNA was detected in 78% of the samples, M. globosa, M. restricta and M. sympodialis were detected at frequencies ranging from 44 to 61%, and M. furfur was found in 11% of healthy subjects. Our results suggest that M. furfur, M. globosa, M. restricta and M. sympodialis are common inhabitants of the skin of both AD patients and healthy subjects, while the skin microflora of patients with AD shows more diversity than that of healthy subjects.

Effect of Gentian Violet, Corticosteroid and Tar Preparations in Staphylococcus-aureus-Colonized Atopic Eczema

Background: In atopic eczema (AE), skin colonization with Staphylococcus aureus plays a possible role in the pathophysiology of the disease. Methods: Thirty-eight patients with AE were screened for their cutaneous colonization with S. aureus. The antibacterial and clinical efficacy of topical therapy with the antiseptic dye gentian violet, a potent glucocorticosteroid or a tar solution (liquor carbonis detergens) was evaluated in vivo in 21 patients with a density of >10⁴ CFU/cm² and in vitro. Skin sites were treated twice daily for 4 days with the active drug or a corresponding control. Quantification of S. aureus was done daily during therapy as well as 3 days thereafter. The severity of the lesions was rated by a regional SCORAD. Results: In gentian-violet-treated skin, bacterial density decreased significantly in lesional (p < 0.001) and unaffected skin (p < 0.001). Bacterial densities did not decrease during therapy with glucocorticosteroid or liquor carbonis detergens but dropped afterwards. All therapeutics reduced the severity score, reduction being greatest for the glucocorticosteroid and lowest for liquor carbonis detergens. In vitro, a high antibactericidal efficacy was demonstrated only for gentian violet. Conclusions: Antibacterial therapy with gentian violet not only reduces S. aureus dramatically, but also reduces the severity of the eczema. Reduction of S. aureus after therapy with glucocorticosteroids and LCD seems to be secondary to improvement of the skin condition.

Epidemiological significance of cutaneous, pharyngeal, and digestive tract colonization by multiresistant Acinetobacter baumannii in ICU patients

The aim of this prospective study was to assess the relative epidemiological role of digestive tract colonization by Acinetobacter baumannii, in comparison with other body site colonizations, in patients admitted to intensive care units (ICUs). From January to May 1995, axillary, pharyngeal and rectal swabs were taken together within the first 48 h of admission, and then weekly during ICU stay. Seventy-three patients were included, 48 of them (66%) had axillary, pharyngeal, or rectal colonization with A. baumannii, nine (19%) of these 48 during the first 48 h and the remaining 28 (77%) during the first week. Twenty-one (29%) had clinical samples positive for A. baumannii and axillary, pharyngeal, or rectal colonization. In 15 of these 21 (71%), colonization on body sites occurred prior to isolation from clinical samples (mean seven days, range 1–20). Throughout admission, rates of detection of A. baumannii were 75% ( 36 48 ) for axillary or pharyngeal swabs and 77% ( 37 48 ) for rectal swabs. Combination of two body site swabs yielded culture positive rates of 90% ( 43 48 ) for axillary-pharyngeal or axillary-rectal sites, and 96% ( 46 48 ) for pharyngeal-rectal. Two epidemic clones were defined by antibiotype and pulsed-field gel electrophoresis (PFGE) of SmaI DNA digests in 43 isolates from 11 patients. We conclude that body sites of patients were a major reservoir for A. baumannii infections in the outbreak. This finding casts doubt on the value of selective decontamination of the digestive tract as an additional infection control measure in this kind of outbreak. The weekly performance of pharyngeal and rectal swabs appears to detect A. baumannii colonization early among ICU patients and enables barrier methods to be applied rapidly.

T-Cell Proliferation to Superantigen-Releasing Staphylococcus aureus by MHC Class II-Bearing Keratinocytes under Protection from Bacterial Cytolysin

Skin colonization with Staphylococcus aureus may exacerbate skin disorders by activation of lesional T cells with release of superantigens. Although T cells are effectively stimulated by staphylococcal superantigens in the presence of epidermal accessory cells, it remains to be elucidated whether in vivo cutaneous colonization with S. aureus can activate T cells. We examined how T cells are stimulated in the presence of keratinocytes by mitomycin C (MMC)-treated S. aureus that are unable to propagate but retain their ability to produce superantigens. Peripheral blood mononuclear cells (PBMCs) proliferated well in response to MMC-treated superantigen-producing S. aureus and bacterial supernatants. When purified T cells were cultured with MMC-treated S. aureus or supernatant in the presence of interferon-gamma-pre-treated keratinocytes, the supernatant, but not MMC-treated S. aureus, stimulated T cells. MMC-treated S. aureus had a cytotoxic effect on keratinocytes. Furthermore, keratinocytes were highly susceptible to alpha-toxin compared with monocytes and B cells functioning as accessory cells in PBMCs. This suggests that a lack of response of T cells to S. aureus plus keratinocytes is due to damage of superantigen-presenting function of keratinocytes by cytolysin. The activity of alpha-toxin was much less stable than that of superantigen during incubation. Given that S. aureus-colonized skin provides circumstances in which viable keratinocytes are exposed to superantigens but not to active cytolysin(s), skin-infiltrating T cells may be effectively stimulated by S. aureus.

Double-Blind Prospective Randomized Study Comparing Topical Mupirocin and Placebo for the Prevention of Infection Associated with Central Venous Catheters

To compare the incidence of exit site colonization, local catheter-related infection and catheter-related bacteremia in patients randomized to receive either topical 2% mupirocin or placebo at the catheter exit site. Patients requiring central venous catheters for more than three days were randomized to receive in a double-blind fashion either topical mupirocin or an identical placebo at the exit site three times weekly at the time of dressing change. Insertion, site care and removal of catheters were standardized. Serial semiquantitataive cultures of the skin at the catheter insertion site were performed using a sterile 25 cm(2) template. The distal and proximal catheter segments were cultured using a standardized semiquantitative technique, and any suspect catheter-related bacteremia was investigated with two sets of peripheral blood cultures, a 10 mL sample of infusate and clinical assessment. Both univariate and multivariate analyses were conducted on individual risk factors to determine factors that might influence the outcomes of local or systemic catheter-related infection. Local catheter-related infection (defined as more than 15 colony forming units [cfu] on culture of the proximal or distal catheter segment) occurred in six of 57 (10.5%) in the mupirocin group versus 18 of 69 (26%) in the placebo group (P<0.05) for the distal catheter segments and in one of 40 (2.5%) versus 13 of 47 (27.6%) for the proximal segments in the mupirocin and placebo groups (P<0.006), respectively. Catheter-related bacteremia occurred in one of 57 (1.8%) of the mupirocin group but in five of 69 (7.2%) of the placebo group (P=0.15). Stepwise logistic regression revealed that cutaneous colonization at the insertion site of at least 10(3) cfu/mL/25 cm(2) (OR 2.6; CI 1.0 to 6.9) and the use of placebo (OR 3.3; CI 1.2 to 9.0) were significant factors predicting local catheter-related infection; whereas mupirocin was associated with reciprocal protective effect (OR 0.3; 95% CI 0.1 to 0.8). These findings suggest that patients receiving topical mupirocin at the exit site for long term central venous catheters have significantly less local catheter-related infection, and there is a trend towards less catheter-related bacteremia.

A prospective, randomized trial of gauze and two polyurethane dressings for site care of pulmonary artery catheters: Implications for catheter management

To compare the safety of a conventional polyurethane transparent dressing and a novel highly permeable polyurethane dressing, as compared with standard gauze and tape, as site dressings for pulmonary artery catheters; and to rigorously determine the sources of bloodstream infections deriving from these catheters. Prospective, randomized, clinical trial. General adult intensive care units (ICUs) in a university hospital. A total of 442 adult patients with pulmonary artery catheters were studied. Two thirds of the catheters had been inserted in the operating room and one third had been inserted in an ICU. Patients were randomized at the time of pulmonary artery catheter insertion to have one of three dressing regimens: a) sterile gauze and tape (control), replaced every 2 days; b) a conventional polyurethane dressing, replaced every 5 days; or c) a highly permeable polyurethane dressing, also replaced every 5 days. The origin of each catheter-associated bloodstream infection was sought by quantitatively culturing the skin of the insertion site and all potential sources on the catheter, including the hub and infusate from each lumen of the introducer sheath and the pulmonary artery catheter, and intravascular segments of the introducer sheath and pulmonary artery catheter. Bloodstream infection was confirmed by demonstrating concordance between isolates from the device and blood cultures by pulsed-field electrophoresis of genomic DNA, digested with low-frequency-cleavage, restriction endonucleases. One hundred thirty catheters were randomized to be dressed with sterile gauze and tape (control), 127 with the conventional polyurethane dressing, and 185 with the highly permeable polyurethane dressing. Patients and catheters in the three dressing groups were very comparable. Ninety-six (21.7%) of the 442 catheters studied showed colonization of the introducer sheath or the pulmonary artery catheter, and five (1.1%) catheters caused bloodstream infection. Catheter-related bloodstream infections were associated with concordant cutaneous colonization of the insertion site (n = 2), a contaminated catheter hub or infusate (n = 3), contamination of the extravascular segment of a repositioned catheter beneath the external protective plastic sleeve (n = 1), or hematogenous colonization of the catheter (n = 1). All pulmonary artery catheter-related bloodstream infections occurred with catheters (introducers) in place for > or = 5 days (p < .001). Cutaneous colonization under the dressing at catheter removal was lowest with gauze (10(1.3) colony-forming units), intermediate with the new highly permeable polyurethane dressing (10(1.8) colony-forming units; p < .01), and highest with the conventional polyurethane dressing (10(2.0) colony-forming units; p < .001). There were no significant differences in catheter colonization (20.0 to 25.2 cases per 100 catheters) or catheter-related bloodstream infection (0.8 to 1.6 cases per 100 catheters) between the three groups. The incidence of pulmonary artery catheter-related bloodstream infection has decreased over the past 5 yrs. Pulmonary artery catheter-related bloodstream infections originate from multiple sources, indicating that measures to prevent bacteremic infections of these devices must focus both on reducing cutaneous colonization at the insertion site and averting contamination of infusate and catheter hubs. Efforts should be made to limit the duration of catheterization with pulmonary artery catheters (including the introducer) to no longer than 4 days. The polyurethane dressings studied appear to be safe for use with pulmonary artery catheters and may be left on for up to 5 days between dressing changes.

A prospective, randomized trial of gauze and two polyurethane dressings for site care of pulmonary artery catheters: Implications for catheter management

Objectives: To compare the safety of a conventional polyurethane transparent dressing and a novel highly permeable polyurethane dressing, as compared with standard gauze and tape, as site dressings for pulmonary artery catheters; and to rigorously determine the sources of bloodstream infections deriving from these catheters. Design: Prospective, randomized, clinical trial. Setting: General adult intensive care units (ICUs) in a university hospital. Patients: A total of 442 adult patients with pulmonary artery catheters were studied. Two thirds of the catheters had been inserted in the operating room and one third had been inserted in an ICU. Interventions: Patients were randomized at the time of pulmonary artery catheter insertion to have one of three dressing regimens: a) sterile gauze and tape (control), replaced every 2 days; b) a conventional polyurethane dressing, replaced every 5 days; or c) a highly permeable polyurethane dressing, also replaced every 5 days. Measurements and Main Results: The origin of each catheter-associated bloodstream infection was sought by quantitatively culturing the skin of the insertion site and all potential sources on the catheter, including the hub and infusate from each lumen of the introducer sheath and the pulmonary artery catheter, and intravascular segments of the introducer sheath and pulmonary artery catheter. Bloodstream infection was confirmed by demonstrating concordance between isolates from the device and blood cultures by pulsed-field electrophoresis of genomic DNA, digested with low-frequencycleavage, restriction endonucleases. One hundred thirty catheters were randomized to be dressed with sterile gauze and tape (control), 127 with the conventional polyurethane dressing, and 185 with the highly permeable polyurethane dressing. Patients and catheters in the three dressing groups were very comparable. Ninety-six (21.7%) of the 442 catheters studied showed colonization of the introducer sheath or the pulmonary artery catheter, and five (1.1%) catheters caused bloodstream infection. Catheter-related bloodstream infections were associated with concordant cutaneous colonization of the insertion site (n = 2), a contaminated catheter hub or infusate (n = 3), contamination of the extravascular segment of a repositioned catheter beneath the external protective plastic sleeve (n = 1), or hematogenous colonization of the catheter (n = 1). All pulmonary artery catheter-related bloodstream infections occurred with catheters (introducers) in place for ≥5 days (p< .001). Cutaneous colonization under the dressing at catheter removal was lowest with gauze (101.3 colony-forming units), intermediate with the new highly permeable polyurethane dressing (101.8 colony-forming units;p< .01), and highest with the conventional polyurethane dressing (102.0 colony-forming units;p< .001). There were no significant differences in catheter colonization (20.0 to 25.2 cases per 100 catheters) or catheter-related bloodstream infection (0.8 to 1.6 cases per 100 catheters) between the three groups. Conclusions: The incidence of pulmonary artery catheter-related bloodstream infection has decreased over the past 5 yrs. Pulmonary artery catheter-related bloodstream infections originate from multiple sources, indicating that measures to prevent bacteremic infections of these devices must focus both on reducing cutaneous colonization at the insertion site and averting contamination of infusate and catheter hubs. Efforts should be made to limit the duration of catheterization with pulmonary artery catheters (including the introducer) to no longer than 4 days. The polyurethane dressings studied appear to be safe for use with pulmonary artery catheters and may be left on for up to 5 days between dressing changes. (Crit Care Med 1994; 22:1729–1737)

Selective Intrapartum Prophylaxis for Group B Streptococcus Colonization

OBJECTIVE Intrapartum antibiotic prophylaxis (IAP) in mothers with group B streptococcus (GBS) colonization presents difficult neonatal management decisions. IAP was instituted in response to an increased incidence of early-onset GBS sepsis (EOGBSS), and a study was conducted to evaluate the outcome of these newborns. METHODS A study was undertaken at Truman Medical Center-East, a county hospital with a level 1 nursery. During the 20-month study period, prenatal GBS cultures were obtained on all mothers in their third trimester of pregnancy. At time of delivery, GBS-positive women who had at least one risk factor were to receive IAP. Risk factors included fever and/or amnionitis, premature labor, and prolonged rupture of membranes defined as > 6 hours. Screening laboratory tests were performed on all newborns whose mothers received IAP. Only the newborns with positive screening laboratory tests or symptoms of sepsis received further laboratory evaluation and antibiotic treatment. RESULTS During the study, 2040 mothers gave birth to 2054 newborns. Three hundred thirty-two mothers (16.3%) were colonized with GBS and 122 (37.0%) had at least one risk factor. IAP was given to 70 GBS-positive mothers. Thirty-three (27%) GBS-positive mothers with risk factors did not receive IAP for logistical reasons. Eleven full-term newborns had EOGBSS: For case newborns, the mean duration of ruptured membranes was 13.7 hours (range 2.5 to 28 hours). Vertical transmission occurred as follows: Cutaneous colonization was found in 33 (12.5%) newborns born to 261 mothers who received no IAP, and symptomatic EOGBSS was diagnosed in 9 (3.4%). Mothers who received one dose (n = 43) had three (6.9%) newborns with GBS colonization and two (4.7%) asymptomatic newborns with EOGBSS: No newborns born to 28 mothers who received two doses IAP had GBS colonization or were ill. Cutaneous vertical transmission was reduced (P = .03). Newborns born to GBS-positive mothers with one or more risk factors who received IAP had significantly less EOGBSS (P < .05) than those who did not receive IAP. CONCLUSIONS Selective IAP was administered safely to 21% of GBS-positive women, or 3.5% of all deliveries. IAP prevented EOGBSS when it could be given to GBS-positive mothers with a risk factor. Accurate identification of mothers with GBS colonization and their risk factors is essential for effective use of IAP. Earlier institution of IAP after rupture of membranes may reduce the risk of EOGBSS and the need for extensive infant evaluation.

Selective Intrapartum Prophylaxis for Group B Streptococcus Colonization: Management and Outcome of Newborns

Intrapartum antibiotic prophylaxis (IAP) in mothers with group B streptococcus (GBS) colonization presents difficult neonatal management decisions. IAP was instituted in response to an increased incidence of early-onset GBS sepsis (EOGBSS), and a study was conducted to evaluate the outcome of these newborns. A study was undertaken at Truman Medical Center-East, a county hospital with a level 1 nursery. During the 20-month study period, prenatal GBS cultures were obtained on all mothers in their third trimester of pregnancy. At time of delivery, GBS-positive women who had at least one risk factor were to receive IAP. Risk factors included fever and/or amnionitis, premature labor, and prolonged rupture of membranes defined as > 6 hours. Screening laboratory tests were performed on all newborns whose mothers received IAP. Only the newborns with positive screening laboratory tests or symptoms of sepsis received further laboratory evaluation and antibiotic treatment. During the study, 2040 mothers gave birth to 2054 newborns. Three hundred thirty-two mothers (16.3%) were colonized with GBS and 122 (37.0%) had at least one risk factor. IAP was given to 70 GBS-positive mothers. Thirty-three (27%) GBS-positive mothers with risk factors did not receive IAP for logistical reasons. Eleven full-term newborns had EOGBSS: For case newborns, the mean duration of ruptured membranes was 13.7 hours (range 2.5 to 28 hours). Vertical transmission occurred as follows: Cutaneous colonization was found in 33 (12.5%) newborns born to 261 mothers who received no IAP, and symptomatic EOGBSS was diagnosed in 9 (3.4%). Mothers who received one dose (n = 43) had three (6.9%) newborns with GBS colonization and two (4.7%) asymptomatic newborns with EOGBSS: No newborns born to 28 mothers who received two doses IAP had GBS colonization or were ill. Cutaneous vertical transmission was reduced (P = .03). Newborns born to GBS-positive mothers with one or more risk factors who received IAP had significantly less EOGBSS (P < .05) than those who did not receive IAP. Selective IAP was administered safely to 21% of GBS-positive women, or 3.5% of all deliveries. IAP prevented EOGBSS when it could be given to GBS-positive mothers with a risk factor. Accurate identification of mothers with GBS colonization and their risk factors is essential for effective use of IAP. Earlier institution of IAP after rupture of membranes may reduce the risk of EOGBSS and the need for extensive infant evaluation.

Staphylococcus aureus carriage and HIV-1 disease: association with increased mucocutaneous infections as well as deep soft-tissue infections and sepsis

Cutaneous colonization by<i>Staphylococcus aureus</i>has been found to be significantly increased in patients infected with the human immunodeficiency virus (HIV-1). The incidence of<i>S aureu</i>s carriage was shown to stay relatively constant with disease progression, Walter Reed (WR) stage 1 through 6.¹ <i>Staphylococcus aureus</i>sepsis, deep soft-tissue infections, and pneumonia have all been frequently reported in patients with advancing HIV-1 disease, and<i>S aureus</i>infections, often undiagnosed premortem, were seen in greater than 50% of the patients from one autopsy study.²Trauma, intravenous catheters (peripheral and central lines), intravenous drug abuse, and lymphedema are considered to be risk factors. As part of a study on the natural history of cutaneous disease in HIV-1 disease, patients were followed up prospectively to determine if there was a correlation with infection by<i>S aureus</i>and the stage of disease. <h3>Patients and Methods.</h3> A total of 646 HIV-1—positive patients were

Comparative study of cefazolin, cefamandole, and vancomycin for surgical prophylaxis in cardiac and vascular operations: A double-blind randomized trial

Three-hundred twenty-one adults undergoing cardiac or major vascular operations were randomized to receive intravenous cefazolin, cefamandole, or vancomycin for prophylaxis against surgical infection in a double-blind trial. All three regimens provided therapeutic blood levels throughout operation in patients studied undergoing cardiopulmonary bypass. The prevalence of surgical wound infection was lowest with vancomycin (4 infections [3.7%] versus 14 [12.3%] and 13 [11.5%] in the cefazolin and cefamandole groups, respectively; p = 0.05); there were no thoracic wound infections in cardiac operations in the vancomycin group (p = 0.04). The mean duration of postoperative hospitalization was lowest in the vancomycin group (10.1 days; p < 0.01) and highest in the cefazolin group (12.9 days). Prophylaxis with vancomycin or cefamandole, compared with cefazolin, did not prevent nosocomial cutaneous colonization by methicillin-resistant coagulase-negative staphylococci; colonization or infection with vancomycin-resistant staphylococci or enterococci was not detected. Adverse effects attributable to the prophylactic regimen were infrequent in all three groups. Eight patients given vancomycin became hypotensive during administration of a dose, despite infusion during a 1-hour period; however, slowing the rate of administration and pretreating with diphenhydramine allowed vancomycin to be resumed and prophylaxis completed uneventfully in five of the patients. We conclude that administration of vancomycin (approximately 15 mg/kg), immediately preoperatively, provides therapeutic blood levels for surgical prophylaxis throughout most cardiac and vascular operations, resulting in protection against postoperative infection superior to that obtained with cefazolin or cefamandole. Vancomycin deserves consideration for inclusion in the prophylactic regimen (1) for prosthetic valve replacement and prosthetic vascular graft implantation, to reduce the risk of implant infection by methicillin-resistant coagulase-negative staphylococci and enterococci; (2) for any cardiovascular operation if the patient has recently received broad-spectrum antimicrobial therapy; and (3) for all cardiovascular operations in centers with a high prevalence of surgical infection with methicillin-resistant staphylococci or enterococci. Guidelines for dosing and administration of vancomycin for cardiovascular surgical prophylaxis are provided.

The pathogenesis and epidemiology of catheter-related infection with pulmonary artery Swan-Ganz catheters: A prospective study utilizing molecular subtyping

To delineate the pathogenesis and epidemiology of catheter-related infection with Swan-Ganz pulmonary artery (PA) catheters, a prospective clinical study of hospitalized adult medical and surgical patients was done. Role of catheter material was assessed by randomizing insertions to heparin-bonded PA catheters made of polyvinylchloride or polyurethane. Sources of infection and pathogenesis were studied by culturing skin, the introducer, the PA catheter tip, all hubs, infusate from each lumen, and the extravascular portion of the PA catheter beneath the external protective plastic sleeve. Concordance between isolates from sources and infected catheters was determined by speciation, antibiogram, and for coagulase-negative staphylococci, plasmid profile analysis. Risk factors for infection were determined by stepwise logistic regression. Overall, 65 (22%) of 297 Swan-Ganz catheters showed local infection of the introducer (58 catheters) or the intravascular portion of the PA catheter (20 catheters); only two catheters (0.7%) caused bacteremia. Eighty percent of infected Swan-Ganz catheters (the introducer or PA catheter) showed concordance with organisms cultured from skin of the insertion site, 17% with a contaminated hub and 18% with organisms contaminating the extravascular portion of the PA catheter beneath the sleeve. Isolates from infected PA catheters were most likely to show concordance with concomitantly infected introducers (71%). Cutaneous colonization of the insertion site with > 10 2 cfu/10 cm 2 (relative risk [RR] 5.5; p < 0.001), insertion into an internal jugular vein (RR 4.3; p < 0.01), catheterization >3 days (RR 3.1; p < 0.01), and insertion in the operating room using less stringent barrier precautions (RR 2.1; p = 0.03) were each associated with a significantly increased risk of catheter-related infection. The risk of bacteremic infection with Swan-Ganz catheters is now low, in the range of 1%, with reasonable care. Swan-Ganz catheters are vulnerable to contamination from multiple sources, but the patient's skin is the single most important source of organisms causing invasive infection, which in most cases involves the introducer rather than the PA catheter. Heavy colonization of the insertion site, percutaneous insertion in the internal jugular vein rather than subclavian vein, catheterization longer than 3 days, and insertion with less stringent barrier precautions significantly increase the risk of catheter-related infection. These findings hold promise for application to management of Swan-Ganz catheters and research in catheter design to reduce the risk of catheter-related infection.

Evaluation of Dressing Regimens for Prevention of Infection With Peripheral Intravenous Catheters

Four dressing regimens for peripheral venous catheters were studied in a prospective randomized clinical trial with 2088 Teflon catheters: (1) sterile gauze, replaced every other day, and three dressings left on for the lifetime of the catheter; (2) gauze; (3) a transparent polyurethane dressing; and (4) an iodophor-transparent dressing. The four dressings provided comparable coverage, except moisture accumulated more frequently under the transparent dressings (26% to 28% vs 20% to 21%). Cutaneous colonization under the dressing was low level and comparable with all four dressings (range, 10(0.58) to 10(0.70) colony-forming units). The rate of local catheter-related infection (greater than or equal to 15 colony-forming units) was also low and did not differ significantly (range, 4.6% to 5.9%); no catheter caused bacteremia. Stepwise logistic multivariate analysis showed cutaneous colonization of the insertion site (relative risk [RR] of infection, 3.86), contamination of the catheter hub (RR, 3.78), moisture under the dressing (RR, 2.48), and prolonged catheterization (RR, 1.75) to be significant risk factors for catheter-related infection. These data indicate that it is not cost-effective to redress peripheral venous catheters at periodic intervals; for most patients, either sterile gauze or a transparent dressing can be used and left on until the catheter is removed.

Evolution of the hyperimmunoglobulin E and recurrent infection (HIE, JOB'S) syndrome in a young girl

The hyperimmunoglobulin E and recurrent infection syndrome is difficult to diagnose in children with markedly elevated IgE and recurrent superficial Staphylococcus aureus infections who have not presented with a severe infection. The patient, the child of a woman with HIE, had elevated cord blood IgE. In early infancy, she had cutaneous colonization with S. aureus followed by frank impetiginous lesions. Anti- S. aureus IgE was easily detected with a highly specific ELISA assay at 2 years of age (2 years before her presentation with a S. aureus subcutaneous abscess). Thus, the measurement of anti- S. aureus IgE by this technique may be a useful laboratory test for the diagnosis of HIE before the appearance of a severe infection.