Bacterial translocation from the gut to mesenteric lymph nodes and other extraintestinal sites is an important source of infection in acute pancreatitis. Impaired host immunity is known to promote bacterial translocation. Interleukin-6 (IL-6) is a multifunctional cytokine that regulates the immune response, acute phase reaction, and hematopoiesis.Twenty-four mongrel dogs (18-29 kg) were studied in four equal groups. In Groups I and II, acute pancreatitis was induced by direct pressure injection of 4% taurocholate and trypsin into the pancreatic duct at laparotomy. Groups III and IV had only laparotomy. Group I and III dogs were given IL-6 (50 microg/kg/d, sq) daily starting 24 h after operation and Group II and IV dogs received an equal volume of saline administered at similar time. All animals had blood drawn for culture, complete blood count (CBC), platelets, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and amylase on d 0, 1, 4, and 7. On d 7, mesenteric lymph nodes (MLN), spleen, liver, pancreas, and cecum were harvested for pathology study and for cultures of aerobic and anaerobic bacteria. Quantitative cecal cultures of aerobic and anaerobic bacteria were obtained.All Group I and Group II dogs had severe pancreatitis. The increase of plasma CRP in Group I was sustained throughout treatment (1.3+/-0.3 on d 0 vs 3.1+/-0.3*, 3.0+/-0.3*, and 2.9+/-0.3* on d 1,4, and 7, respectively). Plasma CRP was increased in Group II on d 1 and d 4 (1.3+/-0.3 mg/dL on d 0 vs 3.6+/-0.3* mg/dL on d 1, and 3.1+/-0.3* on d 4, *p < 0.05). There were no differences in white blood cell (WBC) count, differential, platelets, and ESR between Groups I and II. Bacterial translocation to MLN was lower in Group I (1/6) than in Group II (6/6) (p < 0.05). All 6 dogs in Group II had bacterial spread to distant sites compared to 2 of 6 dogs in Group I (p = 0.066). Both MLN and other distant organ cultures were negative in Group III and only 1 of 6 MLN cultures was positive in Group IV.IL-6 treatment decreases bacterial translocation to MLN and may be beneficial in reducing septic complications in acute pancreatitis.
Selective decontamination of the oropharynx and gastrointestinal tract with nonabsorbable antimicrobials and sucralfate, a stress ulcer prophylactic that maintains the normal gastric acid bacterial barrier, were compared for prevention of pneumonia in a cardiac surgery intensive care unit. Over 8 months, 51 patients received selective decontamination and 56 received sucralfate. The selective decontamination regimen included polymyxin, gentamicin, and nystatin given as an oral paste and as a solution; patients also received standard antacid or histamin~ blocker stress ulcer prophylaxis. Patients in the selective decontamination group had significantly less colonization of the oropharynx and stomach by gram-negative bacilli (12% vs. 55%, P < .001), significantly fewer infections due to gram-negative bacilli (6% vs. 20%, P =.02), and fewer infections overall (12% vs. 27%, P = .04). There was one episode of pneumonia in the selective decontamination group and five in the sucralfate group. Mortality and length of stay did not differ between the groups, but those receiving selective decontamination had less than one-third as many days of systemic antibiotic therapy with no increase in colonization or infection with resistant gram-negative bacilli. Thus, selective decontamination appeared to reduce both extrapulmonary and pulmonary infections.
Objectives: To compare routine glove use by healthcare workers for all residents, without use of contact‐isolation precautions, with contact‐isolation precautions for the care of residents who had vancomycin‐resistant enterococci or methicillin‐resistant Staphylococcus aureus isolated from a clinical culture Design: Random allocation of two similar sections of the skilled‐care unit to one of the infection‐control strategies during an 18‐month study period. Setting: Skilled‐care unit of a 667‐bed acute‐ and long‐term care facility. Participants: All residents present or admitted to the skilled‐care unit from June 1, 1998, through December 7, 1999. Measurements: Resident acquisition of four antimicrobial‐resistant organisms (methicillin‐resistant Staphylococcus aureus , vancomycin‐resistant enterococci, or extended‐spectrum β‐lactamase‐producing Klebsiella pneumoniae or Escherichia coli ). All isolates were strain typed. The facility level costs associated with each strategy were estimated. Results: Resident acquisition of antimicrobial‐resistant organisms was no different in the glove‐use and isolation‐precautions sections (31 episodes (1.5 per 1,000 resident‐days) vs 38 episodes (1.6 per 1,000 resident‐days)). Acquisition of either of two prevalent K. pneumoniae strains was more likely ( P =.06) in residents in the isolation‐precautions section. The estimated costs of contact‐isolation precautions were 40% greater than those of routine glove use. Conclusion: There was a similar frequency of transmission of antimicrobial‐resistant bacteria in the two study sections; there was evidence for resident‐to‐resident K. pneumoniae transmission in the isolation‐precautions section. Routine glove use for healthcare workers, which decreases resident social isolation and healthcare facility costs, may be preferable in many long‐term care facilities.
In 1979, gentamicin-resistant (Gmr) Staphylococcus aureus was recovered from the clinical specimens of 22 epidemiologically unrelated hospitalized patients; 78% of the patients evaluated were also colonized with Gmr coagulase-negative staphylococci. Endonuclease fingerprinting was used to compare the Gmr plasmids within pairs of isolates of S. aureus and coagulase-negative staphylococci recovered from nine patients. Plasmids differed between pairs but were concordant within four pairs. Thus, in vivo interspecific plasmid transfer, although infrequent, may be important in the sporadic occurrence of Gmr S. aureus. To define the epidemiology of endemic Gmr coagulase-negative staphylococci, culture surveys were performed over two years. Gmr coagulase-negative staphylococci were acquired by 80% of the infants in a special-care nursery that previously had an outbreak of Gmr S. aureus. Among adult inpatients, a 48% colonization rate was related to prior exposure to antibiotics. In contrast, no colonization was found in outpatients or antepartum mothers.
Genotypic variation and stability of isolates of vancomycin-resistant enterococci (VRE) were studied to determine genetic diversity and whether strain definition based on pulsed-field gel electrophoresis (PFGE) is applicable to an endemic setting. Twenty-two PFGE types were identified among 455 VRE isolates. One-on-one comparisons of 10 vanA Enterococcus faecium strain types all yielded > 10 band differences. Variations among vanA and vanB E. faecium isolates from individual long-term- colonized (4–160 days) patients yielded <3 band differences for >85% of comparisons. Comparison of all strains without grouping by vancomycin resistance types yielded two peaks of band differences: one with <3 and one with >10 band differences. These data show that VRE isolates were genetically closely related or very different; demonstrate that within individual patients, VRE isolates show little genetic variation; and provide empirical evidence that PFGE can be used to study the epidemiology of VRE endemicity.
Eighty-seven isolates of Pseudomonas, Enterobacteriaceae , and Staphylococcus , chosen because of their resistance to other aminoglycosides, were tested for susceptibility to 5-episisomicin. Tests were performed in Mueller-Hinton agar and also, with 38 of these isolates, in Mueller-Hinton broth. Of Enterobacteriaceae , 85 and 95.5% were inhibited by 5 and 10 μg of 5-episisomicin per ml, respectively. Amikacin inhibited 74 and 91% of the strains at 10 and 20 μg/ml, respectively. Fifty-four percent of P. aeruginosa were inhibited by 5-episisomicin and amikacin. Eighty-three percent of S. aureus were inhibited by netilmicin and amikacin, whereas only 50% were inhibited by 5-episisomicin. Isolates resistant to 5-episisomicin were most often resistant to the other aminoglycosides and occurred in gram-negative bacilli that did not carry aminoglycoside-modifying enzymes. Five of 23 isolates that carried a 6′- N -acetyltransferase (AAC-6′) and one of two that carried an aminoglycoside 3-acetyltransferase were resistant to and acetylate 5-episisomicin. Strains carrying other aminoglycoside-modifying enzymes were inhibited by 5-episisomicin. Thus, 5-episisomicin is a promising aminoglycoside not attacked by most aminoglycoside-modifying enzymes. Resistance will probably most often be based upon nonenzymatic mechanisms which will also affect other aminoglycosides.
The hypothesis that emergence of gentamicin-resistant strains of Staphylococcus aureus and Staphylococcus epidermidis in a neonatal special care nursery was the result of transfer of a single plasmid between these two species was examined. In experiments with mixtures of staphylococci, either in mixed cultures or on human skin, isolates of S. aureus and S. epidermidis transferred their gentamicin-resistance plasmids both intraand interspecifically. By electron microscopy, the molecular masses of the plasmids from S. aureus and S. epidermidis were the same, 12.2 ± 0.36 (standard deviation) and 12.3 ± 0.56 megadaltons, respectively. Restriction endonuclease analysis of the plasmids from five isolates of S. aureus and two isolates of S. epidermidis, with use of the enzymes HaeIII, EcoRI, XbaI, and HindiII, showed no differences in the digestion patterns of the seven gentamicin-resistance plasmids. The results supported the hypothesis that plasmid transfer between S. aureus and S. epidermidis occurs in nature.
To assess the prevalence of skin and rectal colonization by vancomycin-resistant enterococci (VRE) in hospitalized bacteremic patients and to determine the relation between colonization and bacteremia, we compared 14 case patients who had bacteremia due to VRE with 30 control patients who had bacteremia due to other pathogens. Rectal colonization and skin (inguinal area and/or antecubital fossa) colonization with VRE were common among both case patients (100% had rectal colonization, and 86% had skin colonization) and control patients (37% had rectal colonization and 23% had skin colonization). Among patients with rectal colonization, skin colonization was more common when diarrhea or fecal incontinence was present. The bloodstream cleared without appropriate antimicrobial therapy in nine of the 14 patients with bacteremia due to VRE. The high prevalence of skin colonization with VRE may increase the risk of catheter-related sepsis, cross-infection, or blood culture contamination (which may explain the frequent spontaneous resolution of bacteremia due to VRE).
