Disseminated varicella-zoster virus infection with the syndrome of inappropriate antidiuretic hormone.

A patient with non-Hodgkin's lymphoma who was previously treated with chemotherapy and radiotherapy was seen with intestinal pseudoobstruction due to paralytic ileus associated with herpes zoster (varicella zoster) infection. The infection was accompanied by a polydermatomal rash with typical morphologic characteristics, followed by cutaneous dissemination and the syndrome of inappropriate antidiuretic hormone (SIADH), as well as myotomal paresis. The diagnosis was supported by cytology and by culture of the virus from the CSF. The isolation of the virus from the CSF, coupled with abnormalities of the patient's mental status and CSF, indicate that meningoencephalitis occurred and probably accounted for the SIADH. The patient had a spontaneous and complete recovery. To our knowledge, this is the first report of SIADH associated with herpes zoster infection.

Vancomycin-resistant enterococci in intensive care units: high frequency of stool carriage during a non-outbreak period.

BACKGROUND: We aimed to define the epidemiological associations of vancomycin-resistant enterococci (VRE) in intensive care units (ICUs) during a non-outbreak period by examining prevalence, risk factors for colonization, frequency of acquisition, and molecular strain types. DESIGN: A prospective cohort design was followed. Consecutive patient admissions to 2 surgical ICUs at a tertiary care hospital were enrolled. The main outcome measures were results of serial surveillance cultures screened for VRE. RESULTS: Of 290 patients enrolled, 35 (12%) had colonization with VRE on admission. The VRE colonization or infection had been previously detected by clinical cultures in only 4 of these patients. Using logistic regression, VRE colonization at the time of ICU admission was associated with second- and third-generation cephalosporins (odds ratio [OR] = 6.0, P<.0001), length of stay prior to surgical ICU admission (OR = 1.06, P = .001) greater than 1 prior ICU stay (OR = 9.6, P = .002), and a history of solid-organ transplantation (OR = 3.8, P = .021). Eleven (12.8%) of 78 patients with follow-up cultures acquired VRE. By pulsed-field gel electrophoresis, 2 strains predominated, one of which was associated with an overt outbreak on a non-ICU ward near the end of the study period. CONCLUSIONS: Colonization was common and usually not recognized by clinical culture. Most patients who had colonization with VRE and were on the surgical ICU acquired VRE prior to surgical ICU entry. Exposure to second- and third-generation cephalosporins, but not vancomycin, was an independent risk factor for colonization. Prospective surveillance of hospitalized patients may yield useful insights about the dissemination of nosocomial VRE beyond what is appreciated by clinical cultures alone.

Pseudallescheria boydii infection of the central nervous system.

Pseudallescheria boydii is a rare cause of central nervous system infection characteristically presenting as a neutrophilic meningitis or multiple brain abscesses. Factors predisposing to central nervous system infection with this fungus include immunosuppression and near drowning. The organism is infrequently cultured from fluid obtained by lumbar puncture, delaying clinical recognition and appropriate antifungal therapy. All untreated patients with P boydii infection of the central nervous system died. We describe a patient who developed a persistent neutrophilic meningitis with focal neurologic deficits due to P boydii 6 months after a freshwater aspiration pneumonia. We also review the characteristic clinical and pathologic features of previously reported cases and emphasize the importance of early detection and treatment in the management of this frequently intractable disease.

Molecular typing of coagulase-negative staphylococci from blood cultures does not correlate with clinical criteria for true bacteremia.

PURPOSE: Determining whether a blood culture that contains coagulase-negative staphylococci represents bacteremia or contamination is a clinical dilemma. We compared molecular-typing results of coagulase-negative staphylococcal blood culture isolates with clinical criteria for true bacteremia. SUBJECTS AND METHODS: Pulsed-field gel electrophoresis and arbitrary primed polymerase chain reaction (PCR) were used to determine whether patients with two or more blood cultures with coagulase-negative staphylococcal isolates had the same strain of organism in each culture (same strain bacteremia). We evaluated three different clinical criteria for bacteremia: whether the patient received more than 4 days of antibiotics, whether there was an explicit note in the medical chart in which the physician diagnosed a true bacteremia, and the Centers for Disease Control surveillance criteria for primary bloodstream infection. Agreement between same-strain bacteremia and each definition was examined, based on the assumption that most true infections should be the result of a single strain. RESULTS: The study sample consisted of 42 patients and 106 isolates. Nineteen of the 42 bacteremias (45%) were the same strain. Classification of bacteremias as same-strain correlated poorly with all three clinical assessments (range of percent agreement, 50% to 57%; range of kappa statistic, 0.01 to 0.15). There were both false-positive and false-negative errors. Patients with three or more positive blood cultures were more likely to have same-strain bacteremia than those with only two positive cultures [11 of 15 (73%) vs 8 of 27 (30%), P = 0.006]. Pulsed-field gel electrophoresis was more discriminating than arbitrary primed PCR (percent agreement, 83%; kappa, 0.67). CONCLUSION: Molecular typing correlated poorly with clinical criteria for true bacteremia, suggesting either that true bacteremias are frequently the result of multiple strains or that the commonly used clinical criteria are not accurate for distinguishing contamination from true bacteremia. Vancomycin treatment of clinically defined coagulase-negative staphylococcal bacteremia may frequently be unnecessary.

Clinical and molecular epidemiology of sporadic and clustered cases of nosocomial Clostridium difficile diarrhea.

PURPOSE: A prospective clinical and molecular epidemiologic study was conducted to define the frequency of nosocomial Clostridium difficile patient-to-patient transmission in an urban tertiary referral hospital. PATIENTS AND METHODS: Over a 6-month period, environmental cultures for C difficile were obtained from patients with new positive stool cytotoxin assay (index cases); stool samples were obtained from selected patient contacts (the roommate, occupants of adjacent rooms, and the patient occupying the index room after discharge of the index case); and hand cultures were obtained from personnel contacts. C difficile isolates were analyzed by pulse-field gel electrophoresis (PFGE) or, for isolates that were nontypeable by PFGE, by restriction enzyme analysis. RESULTS: During the study period, we identified 98 index cases of C difficile toxin-associated diarrhea, including focal outbreaks on two wards totaling 26 cases within a 2-month interval. Environmental contamination was detected at > or = 1 sites in 58% of rooms and often involved wide dispersed areas. Among 99 prospectively identified patient contacts, C difficile was cultured from the stool of 31 (31%), including 12 with diarrhea and 19 who were asymptomatic. C difficile was cultured from the hands of 10 (14%) of 73 personnel. Molecular analysis resolved 31 typing profiles among the index isolates; the most common profile (designated strain D1) was represented by 30 isolates. Among the isolates from patient contacts, 5 of 12 from symptomatic contacts matched the corresponding index isolate, and only 1 of 19 from asymptomatically colonized contacts matched. Transmission to personnel or patient contacts of the strain cultured from the corresponding index case was correlated strongly with the intensity of environmental contamination. Strain D1 was frequently represented among isolates associated with heavy environmental contamination, with personnel carriage, and with development of symptomatic illness among prospectively identified contacts. CONCLUSIONS: Intense environmental contamination and transmission to close personnel and patient contacts represented coordinated properties of an individual epidemic strain. For most epidemiologically linked contacts, positive cultures for C difficile did not result from transmission from the presumed index case.

Stool colonization of healthcare workers with selected resistant bacteria.

We examined the carriage of selected resistant bacteria in the stools of healthcare workers who provided direct patient care. Neither vancomycin-resistant enterococci, methicillin-resistant Staphylococcus aureus, nor Clostridium difficile was recovered from the 55 stool specimens collected. A ceftazidime-resistant Citrobacter freundii was isolated from one specimen. We conclude that the stool of healthcare workers is colonized infrequently with these resistant organisms.

Carriage of methicillin-resistant Staphylococcus aureus at hospital admission.

OBJECTIVES: To measure the prevalence of, and to establish predictors for, the nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) at hospital admission. To evaluate mannitol-salt agar with oxacillin for the simultaneous detection and identification of MRSA from nasal swabs. DESIGN: Three-month prospective case-control survey, with data collected from interviews and computerized databases. The criterion standard for MRSA detection was culture on Mueller-Hinton agar with oxacillin 6 microg/mL (National Committee for Clinical Laboratory Standards method). SETTING: 320-bed tertiary-care hospital. PATIENTS: 387 patients screened within 24 hours after admission, including 10 MRSA carriers (cases), 291 patients with no S aureus, and 86 patients with methicillin-susceptible S aureus. RESULTS: The prevalence of MRSA nasal carriage was 2.6%, whereas the prevalence of carriage was 3.1% when both nasal and wound cultures were performed. The significant predictors of carriage were a prior detection of MRSA, open wounds, diabetes mellitus, treatments by injection, prior nursing home stays, visits at home by a nurse, and prior antibiotic treatments. Cases had stayed for longer periods in hospitals and had received longer antibiotic treatments within a year. Eighty patients (including the 10 cases) had diabetes, had been exposed to healthcare facilities within a year, and had antibiotics within 6 months. The sensitivity and negative predictive value of nasal swabs on mannitol-salt agar with oxacillin were 60% and 71%, respectively. CONCLUSION: MRSA carriage on admission to the hospital may be an increasing and underestimated problem. Further studies are needed to develop and validate a sensitive and specific prediction rule.

Intestinal parasites among Southeast Asian refugees in Massachusetts.

This laboratory examined 2,158 stool specimens for intestinal parasites from 1,478 Southeast Asian refugees who immigrated to Massachusetts between September 1981 and April 1982. Seventy-five per cent of refugees harbored one or more of 20 different species of intestinal parasites. Multiple infections occurred in 49% of refugees. Twenty-one per cent had pathogenic protozoa, which are transmissible from person to person. Six per cent had nonpathogenic protozoa only. Entamoeba polecki, an ameba rarely seen in the United States, was found in 5% of refugees.

Evaluation of a direct fluorescent antibody staining method for rapid identification of members of the bacteroides fragilis group.

A direct fluorescent antibody test kit (Fluorotec-F, Pfizer Inc., New York, New York) designed for rapid identification of members of the Bacteroides fragilis group (BFG) was evaluated. Tested were 228 clinical specimens (144 direct smears of clinical material, 14 smears of positive blood cultures, and 70 smears of colonies isolated from clinical material) and 49 reference strains of anaerobic bacteria, including 23 members of the BFG. Fluorotec-F detected 68 of 69 (98.5%) members of the BFG, including 55 B. fragilis, 12 B. thetaiotaomicron, and two B. ovatus, identified by cultural methods in all clinical specimens. Three specimens that yielded B. uniformis also fluoresced. Three specimens fluoresced but failed to yield members of the BFG or B. uniformis on culture. Of the 49 reference strains tested, all strains of B. fragilis, B. thetaiotaomicron, nd B. uniformis tested were detected by Fluorotec-F, but only five of a total of 14B. vulgatus, B. distasonis, and B. ovatus tested fluoresced. Of the 25 reference strains of anaerobic bacteria not belonging to the BFG, none fluoresced except for two strains of B. eggerthii. Direct fluorescent antibody staining of smears of clinical specimens suitable for anaerobic culture is a valuable tool for rapid detection of B. fragilis infections.

Detection of bacteremia with the BACTEC 16B resin blood culture medium.

A new blood culture medium (16B) containing adsorbent and cationic exchange resins has become available for use with the BACTEC instrument (Johnston Laboratories, Towson, MD). Its purpose is to enhance the detection of bacteremia through binding of antimicrobials. The performance of the BACTEC 16B resin medium was compared with the routine BACTEC 6B medium in patients with suspected sepsis receiving antibiotics. A total of 1,227 blood specimens were inoculated in 6B and 16B media and yielded 93 positive cultures from 43 clinically septic patients. Of 103 bacterial isolates recovered, 63 (61.2%) were recovered in both media, 14 (13.6%) in the routine 6B medium only, and 26 (25.2%) in the resin medium only (P greater than 0.05). Staphylococci, both coagulase positive and negative, were recovered much more frequently in resin medium (P less than 0.01). When the results of all the blood culture sets collected for each patient on any given day were considered, the routine 6B medium was the only source of isolation for seven bacterial species in six patients, and the resin medium was the only source of isolation for nine species in nine patients. However, of the nine organisms whose sole isolation source was the resin medium, eight were recovered early in the course of antibiotic therapy (6 within 24 to 36 hours and 2 within 36 to 48 hours of the first antibiotic dose) and had been isolated previously in routine 6B medium. In no instance was the antibiotic regimen changed as a result of the persistence of the organism in resin medium in the early phases of treatment. The use of resin medium did not improve overall detection time for 63 isolates recovered in both media. In conclusion, although the 16B resin medium did recover a greater number of bacterial isolates, it contributed very little information that might be of use in modifying and improving the treatment of septic patients receiving antimicrobials.

A comparison of the identification of group A streptococci and enterococci by two rapid pyrrolidonyl aminopeptidase methods.

Group A streptococci and enterococci can be differentiated from other streptococci by their ability to cleave L-pyrrolidonyl-beta-napthylamide (PYR). The authors evaluated two pyrrolidonyl aminopeptidase (PYRase) systems--Minitek (BBL Microbiology Systems, Cockeysville, MD) and Identicult-AE (Scott Laboratories, Inc., Fiskeville, RI)--for the presumptive identification of Group A streptococci and enterococci. Eighty-three Group A streptococci, 77 beta-hemolytic non-Group A streptococci, 74 enterococci, 56 nonenterococcal non-beta-hemolytic streptococci, 1 Streptococcus pneumoniae, and 1 Aerococcus were tested. Compared with results obtained with reference methods (bile esculin agar and 6.5% [w/v] sodium chloride for identification of enterococci, and latex agglutination tests by Streptex [Burroughs Wellcome, NC] for grouping of beta-hemolytic streptococci) both the Identicult-AE and MInitek systems were 100% sensitive and specific for identification of both enterococci and Group A beta-hemolytic streptococci. Advantages of the Identicult-AE system compared with Minitek were the use of a smaller inoculum for which subculture was not necessary, incubation at room temperature rather than at 37 degrees C, and lower cost. Both PYRase kits tested, and in particular the Identicult-AE system, were very easy to use and should be considered as rapid, reliable, and cost-effective alternative methods for the presumptive identification of Group A streptococci and enterococci in the clinical laboratory.

Evaluation of a latex agglutination test for diagnosis of Clostridium difficile-associated colitis.

Current methods for diagnosis of Clostridium difficile-associated colitis (CAC) based on detection of cytotoxin B by a tissue culture assay (TCA) require technical expertise and up to 48 hours incubation. Recently, a latex agglutination (LA) test (Marion Laboratories) for rapid diagnosis of CAC has become available. Although early evaluations have been favorable, new evidence suggests that the LA reagent binds a soluble bacterial antigen that is not unique to toxigenic strains of C. difficile. The authors examined 201 stools received for CAC testing by LA and a reference TCA and investigated discrepant results. They obtained 29 LA(+)/TCA(+) and 155 LA(-)/TCA(-) results. Eleven patients had LA(+)/TCA(+) and 155 LA(-)/TCA(-) results. Eleven patients had LA(+)/TCA(-) results and 6 had LA(-)/TCA(+) results. The sensitivity and specificity of the LA were 83% and 93%, respectively, compared with TCA. The predictive values of positive and negative results obtained with the LA were 72% and 96%, respectively. Concentrated broth supernatants and live suspensions of three C. difficile isolates with LA(+)/TCA(-) results were tested in a rabbit ileal loop assay. All failed to demonstrate ability to produce an enterotoxin. The authors conclude that the LA method is suitable for rapid screening, but LA(+) results require confirmation by testing with other methods.

Evaluation of the IDS RapID SS/u system for rapid identification of urinary microorganisms.

The accuracy of a new rapid identification system for common urinary pathogens was compared with that of conventional methods and of miniaturized 18-24-hour identification panels. The rapid system, RapID SS/u (Innovative Diagnostic System Inc., Atlanta, GA) is a non-growth-dependent micro-method that identifies selected gram-negative bacilli, gram-positive cocci, and yeasts in two hours by detection of constitutive enzymes acting on chromogenic substrates. A total of 185 representative clinical urinary isolates were tested, including 24 gram-positive cocci, 140 gram-negative bacilli, and 21 yeasts. Identifications by the rapid system were compared with the ones obtained by reference conventional methods for gram-positive cocci and yeasts. For gram-negative bacilli, identifications were compared with the ones obtained by MicroScan Combo Panel (American MicroScan, Mahwah, NJ), and all discrepancies were resolved by testing with API 20E (Analytab Products, Plainview, NY). Overall, the RapID SS/u system correctly identified to genus 160 of 185 isolates (86.5%). For 14 additional isolates (7.6%) the system provided probability overlap identifications that required further testing. Two (1%) isolates failed to be identified, and nine isolates (4.9%) were misidentified by the system. Discrepancies involved five strains of Citrobacter, one Enterobacter, one Morganella, and one Providencia species. The authors conclude that the RapID SS/u system provided rapid and accurate genus identification of most microorganisms commonly isolated from urine.

Rapid detection of cytomegalovirus in clinical specimens by immunofluorescent staining of shell vial cultures.

A recently described rapid technique for detection of cytomegalovirus (CMV) was evaluated in clinical specimens utilizing indirect immunofluorescent staining (IFA) of shell vial cultures. A total of 266 clinical specimens received for viral isolation were inoculated to commercially available shell vials seeded with human lung fibroblasts (MRC-5), centrifuged at 700 X g for one hour, and stained after 18 hours incubation with monoclonal antibody to CMV early nuclear protein (Biotech Research Laboratories) and fluorescein conjugated goat antimouse IgG (Cappel Laboratories). All specimens were also inoculated to tubes of human lung fibroblasts and observed for cytopathic effect (CPE) for 28 days. Of 54 specimens positive for CMV, 36 were positive by both IFA and CPE, 3 were positive by CPE only, and 15 were positive by IFA only (P less than 0.01 by the chi-square test). Failure to detect CMV associated CPE in 10 of these 15 samples was probably due to concomitant infection with herpes simplex virus or heavy bacterial or fungal contamination. Nine of the 13 patients with IFA-positive CPE-negative specimens had CMV infection documented by other positive cultures. It was concluded that the shell vial IFA rapid technique for detection of CMV is highly specific, more sensitive than conventional isolation, and well suited for application in a clinical virology laboratory.

Evaluation of diagnostic methods for Helicobacter pylori gastritis.

The authors evaluated the use of direct Gram-stained smears, 1- and 24-hour urease broth tests, histologic examination, and culture to detect Helicobacter pylori in 100 gastric biopsy specimens from 97 patients with epigastric symptoms. Twenty-six patients had positive cultures and 27 had H. pylori identifiable in hematoxylin and eosin-stained sections. The gastric biopsy specimens from the 29 patients with culture and/or histologic findings positive for H. pylori showed active gastritis in 27 cases (93%), compared with 26 cases (37%) without H. pylori (P less than 0.0001). Chronic gastritis was present in 25 cases (86%) with H. pylori and 40 cases (56%) without H. pylori (P less than 0.01). Twenty patients had positive Gram-stained smears. Fifteen patients had positive 1-hour urease tests, and 3 had delayed positive 24-hour urease tests. There were no false-positive Gram's stain results, three false-positive 24-hour urease tests, two false-negative histologic results, and three false-negative cultures (one inadvertently incubated anaerobically). The sensitivities of the methods were as follows: 62% for the 24-hour urease test, 69% for direct Gram's stain, 90% for culture, and 93% for histologic examination. The authors conclude that the urease test used in this study has low sensitivity and limited specificity; that the direct Gram-stained smear is a useful, highly specific, rapid screening test; and that the lengthier methods of culture and histologic examination have comparably high sensitivity for the definitive diagnosis of H. pylori gastritis.

An unusual case of splenic abscess and sepsis in an immunocompromised host.

Lactobacilli are important members of the vaginal, gastrointestinal, and oral flora in humans. Although these organisms are usually innocuous, increasing numbers of serious infections attributable to these bacilli have recently been reported. The authors report an unusual case of a patient presenting with a splenic abscess and sepsis resulting from lactobacilli and review the literature describing serious infections caused by these organisms.

Epidemiological analysis of imipenem-resistant Serratia marcescens in hospitalized patients.

Our objective was to examine epidemiological characteristics of hospitalized patients with imipenem-resistant Serratia marcescens. We performed a case-control study using data collected from computerized databases and chart review. Molecular typing by pulsed field gel electrophoresis of available isolates was performed. One hundred and ten patients had Serratia spp isolated during the 23-month study period. Twelve were infected or colonized with S. marcescens resistant or of intermediate susceptibility to imipenem. Eleven of the 12 patients were detected during a seven-month period between August 1994 and February 1995, suggesting the possible occurrence of an outbreak. However, the patients were admitted to different wards and services and, in eight patients, imipenem-resistant S. marcescens were isolated within 48 h or admission. None of the patients had epidemiological links within other institutions. The 12 cases were not more likely to have been exposed to beta-lactam antibiotics, including imipenem, than patients with imipenem-susceptible isolates. Six isolates were available for typing by PFGE; three were indistinguishable or closely related whereas each of the other three isolates were unique. In conclusion both the prevalence of imipenem-resistant S. marcescens and its unusual epidemiologic characteristics warrant further study.

Secretion of beta-lactam antibiotics in pure human pancreatic juice.

The secretion of cephalothin and cefoxitin in stimulated pure pancreatic juice was studied in 13 persons after intravenous administration of antibiotics. Of all these studied, three had acute relapsing pancreatitis, five chronic pancreatitis, and five were control subjects. Antibiotic levels were measured in paired pure pancreatic juice and serum samples at fixed time intervals after administration. Cephalothin was detected in very low levels (1 to 1.8 micrograms/ml) in the pure pancreatic juice of four of the six persons studied (3 micrograms/ml). Although therapeutic levels were not obtained in stimulated pure pancreatic juice with either antibiotic, additional studies evaluating antibiotic levels in unstimulated pure pancreatic juice and in pancreatic tissue would be helpful in assessing the role of antibiotic therapy in the treatment of pancreatitis.

Antimicrobial susceptibility tests and their role in therapeutic drug monitoring.

Principles and techniques of routine and special in vitro antimicrobial susceptibility testing of bacteria are reviewed with emphasis on the advantages, limitations, and potential problems of each method. The utilities of MBC testing and of serum bactericidal titer determination are discussed in the clinical context. The use of testing for possible antibiotic interactions is examined in light of potential benefits and risks of combination antimicrobial therapy.

The molecular and clinical epidemiology of enterobacteriaceae-producing extended-spectrum beta-lactamase in a tertiary care hospital.

To describe the epidemiology of Enterobacteriaceae-producing extended-spectrum beta-lactamase (EP-ESBL) in a non-outbreak setting, and to define the risk factors associated with colonization, a 5-month surveillance study was initiated. Ten of 333 patients were colonized with EP-ESBL, as defined by isoelectric focusing. Klebsiella sp. and Escherichia coli were the species most commonly harbouring these plasmid-mediated enzymes. Of the 16 SHV-producing isolates, 10 were SHV-3-like (pI 7.0) and six were SHV-5-like (pI 8.2). All isolates were resistant to ceftriaxone. Ceftazidime resistance was detected in 50% and 100% of SHV-3-like and SHV-5-like producing isolates, respectively. One patient was colonized with four different SHV-5-like producing Enterobacteriaceae. These isolates carried plasmids that were indistinguishable by restriction endonuclease analysis, indicating broad plasmid transfer within the patient. By logistic regression, haemodialysis was a strong risk factor for colonization with EP-ESBL, suggesting that, in our hospital, horizontal transmission is an important mechanism of dissemination of these resistant pathogens.