Screening for Chlamydia trachomatis infection in college women with a polymerase chain reaction assay.

This study sought to determine factors associated with chlamydial infection in a low-prevalence college health setting and to determine the testing characteristics of a polymerase chain reaction (PCR) assay for chlamydial infection (AMPLICOR chlamydia test; Roche Diagnostic Systems, Indianapolis) in this population. Young women (n = 1,149) at a university student health clinic underwent testing for cervical chlamydial infection by PCR assay and culture; the characteristics of women with and without chlamydial infection were compared. Chlamydial infection was diagnosed for 26 students (2.3%). The sensitivity and specificity of PCR assay and culture were 85% and 100% and 54% and 100%, respectively. Students with chlamydial infection were more likely to be 20 years of age or younger, have symptoms, report prior chlamydial infection or gonorrhea, report exposure to a sexually transmitted disease (STD), be black, or have cervical signs during examination; however, none of these were significant predictors for asymptomatic women. PCR assay detected significantly more cervical infections than did culture in this college student population. These data are consistent with recommendations for testing college women with symptoms, STD exposure, or age of younger than 25 years.

Comparison of direct specimen testing utilizing TestPack strep A with testing of specimens following a two-hour broth enrichment.

In a previous study, we demonstrated that a 2-h enrichment of throat swabs in broth followed by a direct fluorescent antibody test was significantly more sensitive than the Abbott TestPack Strep A for the detection of group-A streptococci. In this study, in an effort to simplify the technique, we utilized broth enrichment with an enzyme immunoassay detection method. A total of 1017 pharyngeal specimens were tested with TestPack Strep A (DTP), culture on a selective streptococcal agar, and a 2-h broth enrichment in Todd-Hewitt broth (THB) followed by TestPack Strep A (ETP). Subculture of the THB was used to arbitrate discordant test results. The sensitivities and specificities respectively were as follows: DTP (69% and 99%), ETP (90% and 98%), and SSA (97% and 100%). This enrichment method offers significantly greater sensitivity than direct testing for antigen yet still allows the potential for finalized same-day reporting of results.

Prevention of infection in critically ill patients by selective decontamination of the digestive tract.

OBJECTIVE: To determine whether selective decontamination of the digestive tract using oral and nonabsorbable antimicrobial agents and parenteral cefotaxime prevents infection in critically ill patients. DESIGN: Randomized, controlled trial without blinding. SETTING: Surgical trauma and medical intensive care units in a tertiary referral hospital. PATIENTS: One hundred fifty patients admitted to surgical trauma and medical intensive care units during a 3-year interval, whose condition suggested a prolonged stay (greater than 3 days). INTERVENTION: Patients were randomly allocated to an experimental group (n = 75) that received cefotaxime, 1 g intravenously every 8 hours for the first 3 days only, and oral, nonabsorbable antibiotics (gentamicin, polymyxin, and nystatin by oral paste and oral liquid) for the entire stay in the intensive care unit. Control patients (n = 75) received usual care. MEASUREMENTS: The number of infections, total hospital days, and deaths, as well as the number of days in intensive care unit, were recorded. RESULTS: Control patients experienced more infections (36 compared with 12, P = 0.04), including bacteremias (14 compared with 4, P = 0.05) and pulmonary infections (14 compared with 4, P = 0.03). Although total hospital days, days in intensive care, and the overall death rate all were lower in the treatment group, these differences were not statistically significant. Clinically important complications of selective decontamination of the digestive tract were not encountered. CONCLUSIONS: Selective decontamination of the digestive tract decreases subsequent infection rates, especially by gram-negative bacilli, in selected patients during long-term stays in the intensive care unit.

Comparison of three methods for detection of group A streptococci in throat swabs.

Group A streptococci are generally detected in throat swabs by (i) rapid antigen tests, (ii) conventional culture, or (iii) combinations of both. Direct fluorescent-antibody testing of a 2-h enrichment broth (FA/EN) was an accepted method for same-day results before the advent of rapid antigen tests. We compared FA/EN in Todd-Hewitt Broth (THB) with conventional culture and a rapid antigen test, TestPack Strep A (TPS). Nine hundred seventy specimens were evaluated in this study. Cultures were performed for 48 h on sheep blood agar (SBA) incubated aerobically and on a selective agar for group A streptococci (SSA) incubated in 5 to 10% CO2. Following a 2-h incubation, the fluorescent-antibody test was performed. A subculture of the centrifuged sediment from the THB enrichment was also done. In comparison with a positive culture on SBA or SSA or subculture of the THB pellet, the sensitivities and specificities of the different methods were as follows: SBA, 92 and 100%; SSA, 92 and 100%; TPS, 68 and 99%; FA/EN, 88 and 98%. The FA/EN method offers the potential for definitive finalized reports on the same day as specimen collection with greater sensitivity than TPS. This study included sequential plating and rapid antigen testing of a single swab. In a separate set of experiments to validate this study design, it was shown that recovery of streptococci from swabs plated sequentially on five plates did not vary with the order of plating and the actual proportion of organisms recovered from a swab on a single plate was only 1%.

Detection of bacteriuria and pyuria by URISCREEN a rapid enzymatic screening test.

A multicenter study was performed to evaluate the ability of the URISCREEN (Analytab Products, Plainview, N.Y.), a 2-min catalase tube test, to detect bacteriuria and pyuria. This test was compared with the Chemstrip LN (BioDynamics, Division of Boehringer Mannheim Diagnostics, Indianapolis, Ind.), a 2-min enzyme dipstick test; a semiquantitative plate culture method was used as the reference test for bacteriuria, and the Gram stain or a quantitative chamber count method was used as the reference test for pyuria. Each test was evaluated for its ability to detect probable pathogens at greater than or equal to 10(2) CFU/ml and/or greater than or equal to 1 leukocyte per oil immersion field, as determined by the Gram stain method, or greater than 10 leukocytes per microliter, as determined by the quantitative count method. A total of 1,500 urine specimens were included in this evaluation. There were 298 specimens with greater than or equal 10(2) CFU/ml and 451 specimens with pyuria. Of the 298 specimens with probable pathogens isolated at various colony counts, 219 specimens had colony counts of greater than or equal to 10(5) CFU/ml, 51 specimens had between 10(4) and 10(5) CFU/ml, and 28 specimens had between 10(2) and less than 10(4) CFU/ml. Both the URISCREEN and the Chemstrip LN detected 93% (204 of 219) of the specimens with probable pathogens at greater than or equal to 10(5) CFU/ml. For the specimens with probable pathogens at greater than or equal to 10(2) CFU/ml, the sensitivities of the URISCREEN and the Chemstrip LN were 86% (256 of 298) and 81% (241 of 298), respectively. Of the 451 specimens with pyuria, the URISCREEN detected 88% (398 of 451) and Chemstrip LN detected 78% (350 if 451). There were 204 specimens with both greater than or equal to 10(2) CFU/ml and pyuria; the sensitivities of both methods were 95% (193 of 204) for these specimens. Overall, there were 545 specimens with probable pathogens at greater than or equal to 10(2) CFU/ml and/or pyuria. The URISCREEN detected 85% (461 of 545), and the Chemstrip LN detected 73% (398 of 545). A majority (76%) of the false-negative results obtained with either method were for specimens without leukocytes in the urine. There were 955 specimens with no probable pathogens or leukocytes. Of these, 28% (270 of 955) were found positive by the URISCREEN and 13% (122 of 955) were found positive by the Chemstrip LN. A majority of the false-positive results were probably due, in part, to the detection of enzymes present in both bacterial and somatic cells by each of the test systems. Overall, the URISCREEN is rapid, manual, easy-to-perform enzymatic test that yields findings similar to those yielded by the Chemstrip LN for specimens with both greater than or equal to 10(2) CFU/ml and pyuria or for specimens with greater than or equal to 10(5) CFU/ml and with or without pyuria. However, when the data were analyzed for either probable pathogens at less 10(5) CFU/ml or pyuria, the sensitivity of the URISCREEN was higher (P less than 0.05).

Urinary tract infection caused by nontyphoidal Salmonella: report of 30 cases.

Thirty cases of nontyphoidal Salmonella bacteriuria were identified by review of cultures performed at the Mayo Clinic (Minn.) from 1985 to 1989 and at the Federal Public Health Laboratory Innsbruck (Austria) from 1979 to 1989. All patients had symptoms of an acute urinary tract infection (UTI). In 24 cases nontyphoidal Salmonella was the sole pathogen isolated. Only 1 patient presented with concomitant gastroenteritis and 2 had experienced episodes of diarrhea during the weeks before the UTI, but 15 patients had positive stool cultures in the absence of a gastrointestinal illness. Among all positive urine cultures at the Mayo Microbiology Laboratory, 0.015% were positive for nontyphoidal Salmonella; at the Federal Public Health Laboratory Innsbruck, 0.024% of organisms cultured from urine were nontyphoidal salmonellae. In the majority of our patients, Salmonella UTI did not differ clinically from UTI caused by other members of the Enterobacteriaceae; only in renal transplant recipients was the course of genitourinary salmonellosis more serious. While some urinary isolates of nontyphoidal Salmonella may be fecal contaminants, all 30 isolates recovered from urine during this study were considered to be the cause of symptomatic UTI.

Campylobacter fetus subspecies fetus infection.

During a six-year period five patients with Campylobacter fetus subspecies fetus infections were seen at the Mayo Clinic in Rochester, Minnesota. Bacteremia was observed in two patients, one presenting with aortic valve endocarditis and the other with abdominal atherosclerotic aortic aneurysm. C. fetus subsp. fetus was isolated from tibial tissue of a patient with osteomyelitis. Diarrhea was the main complaint of two further patients, and was also mentioned by the patient with the aortic aneurysm. Despite the use of incubation conditions and selective media geared to detect only Campylobacter jejuni, C. fetus subsp. fetus was isolated from stool specimens of the two patients with gastrointestinal symptoms. The fact that three of five C. fetus subsp. fetus infections observed in this study were associated with intestinal symptoms further supports the importance of the gastrointestinal tract in the pathogenesis of C. fetus subsp. fetus infections.

Prospective evaluation of the risk of bacteremia associated with transesophageal echocardiography.

BACKGROUND: Transient bacteremia may lead to endocarditis in patients with significant valvular lesions. METHODS AND RESULTS: Because transesophageal echocardiography selects a patient population with a high prevalence of valvular lesions, we prospectively evaluated the risk of transient bacteremia associated with transesophageal echocardiography in 49 patients. Blood cultures were obtained immediately before transesophageal echocardiography and at 5, 10, and 20 minutes after the start of the procedure. For each culture, 30 ml venous blood was obtained and 10 ml was inoculated into each of an Isolator tube, Septi-chek bottle, and a nonvented Trypticase soy broth bottle. Broth cultures were incubated for 14 days. Blood from the Isolator tube was plated onto appropriate media for recovery of bacteria and fungi. Two patients were excluded from analysis because the final two sets of blood cultures could not be obtained. Among the remaining 47 study patients, two preprocedure control blood cultures were positive, and two of 141 subsequent cultures were positive. All isolates were considered contaminants. Thus, we found no significant bacteremia due to pathogenic oral flora during transesophageal echocardiography (0%; 95% CI, 0.0-7.5%). CONCLUSIONS: Although recommendations for antimicrobial prophylaxis for transesophageal echocardiography should be individualized for each patient, many patients may not require antimicrobial prophylaxis.

Campylobacter bacteremia: clinical experience with three different blood culture systems at Mayo Clinic 1984-1990.

The efficiency of three commercially available blood culture systems for isolating Campylobacter sp. was investigated. Thirteen of 189,688 blood cultures from patients seen at the Mayo Clinic from 1984 through 1990 were positive for Campylobacter sp. Eleven out of 13 blood cultures positive for Campylobacter sp. were part of a complete three bottle set of cultures (Isolator from Du Pont, Roche Septi-Chek from Hoffman-La Roche, and non-vented Tryptic Soy Broth from Difco), none of them providing a specific microaerophilic mileu. The aerobic Roche Septi-Chek seems to be more efficient for the detection of Campylobacter sp. in blood cultures than either the anaerobic Tryptic Soy Broth (Difco) or the Isolator (Du Pont) using the incubator condition of 5% CO2.

Cutaneous botryomycosis.

We report four cases of cutaneous botryomycosis. The predisposing factors included alcoholism, diabetes, and trauma. Clinically, the patients had nodules, suppurative plaques, or ulcers. In two cases, Staphylococcus aureus was cultured. In one case Neisseria species was cultured and in another a coagulase-negative Staphylococcus and Corynebacterium species were the only organism cultured. All patients responded to systemic antibiotic therapy.

Application of quadFERM+ for the identification of fastidious gram-positive and gram-negative bacilli.

The 2-hr quadFERM+ kit (qF) (Analytab Products, Plainview, NY) was compared with conventional tube tests for the identification of the HACEK bacteria (Haemophilus aphrophilus, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, Kingella kingae), other Haemophilus and Kingella spp., Capnocytophaga, Corynbacterium, and Moraxella spp. Test results were identical for 296 comparisons with 74 isolates (74%). In the remaining 104 comparisons for 26 isolates, 50 reactions were identical, and qF produced a positive result in 46 of 54 discrepancies.

Evaluation of calcofluor white stain for detection of Pneumocystis carinii.

A rapid calcofluor white (CFW) stain for detecting Pneumocystis carinii was evaluated prospectively. Eighty-nine bronchoalveolar lavage (BAL) specimens, 21 open-lung biopsy (OLB) tissues, 2 induced sputums, 1 expectorated sputum, 2 tracheal secretions, and 1 bronchial secretion from 102 patients were examined for P. carinii cysts by both the CFW stain and a modified methenamine silver (MS) stain. Twenty episodes of P. carinii pneumonia were detected: 19 of these episodes were detected by CFW stain, and 16 of those episodes were detected by MS stain. Discrepancies between the two staining methods were resolved by review of the clinical histories and, in one case, by testing an OLB specimen. Neither staining procedure gave false-positive results with any specimen. More cysts were detected in CFW-stained specimens than in MS-stained specimens (p = 0.05). CFW stain is a simple, rapid, and inexpensive method for detecting P. carinii in clinical specimens and is at least as sensitive as MS stain.

Results of a 6-month survey of stool cultures for Escherichia coli O157:H7.

Escherichia coli O157:H7 is a recently recognized enteric pathogen that causes acute hemorrhagic colitis. Although the infection is usually self-limited, it may be complicated by hemolytic uremic syndrome and thrombotic thrombocytopenic purpura. At our institution, stool specimens are now routinely cultured for this organism. To determine the prevalence of E. coli O157:H7-associated diarrhea in our patient population, we surveyed all submitted stool cultures for 6 months for this organism. Specimens were screened for non-sorbitol fermenting E. coli and confirmed by slide-agglutination and immobilization testing. Of 2,164 specimens, 10 yielded E. coli O157:H7. It was the fourth most common bacterial stool pathogen found. Bloody diarrhea and abdominal pain were the most common symptoms of the infected patients. E. coli O157:H7 causes sporadic infections in our patient population and should be considered in the differential diagnosis of acute hemorrhagic colitis.

Increased efficiency of stool culture for the detection of Salmonella and Shigella.

The Wampole Bactigen Salmonella-Shigella Latex Agglutination Test (SSLA) (Wampole Laboratories, Cranbury, New Jersey) was evaluated as a possible substitute for blind subculture of selenite broths from stool cultures. Recovery rates of Salmonella and Shigella from eosin-methylene blue (EMB) agar were reviewed to determine if this medium could be eliminated from primary stool culture. Salmonella was detected in 17 of 822 stools by both SSLA and culture. There were 52 false-positive SSLA for Salmonella (sensitivity 100%, specificity 93%). Of three Shigella isolated on culture, one was SSLA positive, one was SSLA negative, and one was negative by both SSLA and subculture of selenite broth. There were eight false-positive SSLA for Shigella (specificity 99%). Of 50 Salmonella and 11 Shigella isolated from 6200 stools in 1.5 years, two Shigella were isolated on EMB only. The SSLA test is a useful screening test for Salmonella. By eliminating unnecessary subcultures of selenite broth, it reduces turnaround time by 24 hr for negative stool cultures. The combination of primary culture with SSLA screening of enrichment broth should be adequate for the detection of Salmonella and Shigella from stool specimens. Our data suggest that EMB or other differential medium should be retained for primary culture to enhance detection of Shigella.

Xanthomonas maltophilia: an emerging nosocomial pathogen.

Xanthomonas maltophilia is a potentially pathogenic organism with a broad clinical spectrum. Nosocomial colonization and infection are the most common manifestations. The incidence of clinical isolation of X. maltophilia is on the rise, possibly in part because of the selective pressure from the new antimicrobial agents to which it is resistant. The organism is usually resistant to commonly used antimicrobial agents, including most cephalosporins, aztreonam, antipseudomonal penicillins, imipenem, and the quinolones.

Wound infection caused by Branhamella catarrhalis.

Branhamella catarrhalis was isolated from sputum, tracheal secretions, and a nonhealing and infected thoracic surgical wound in a 59-year-old woman who had a history of a chronic, interstitial fibrosis and who had undergone an open lung biopsy procedure. The patient's upper respiratory tract was the likely source of the organism. To our knowledge, this is the first report of a wound infection caused by B. catarrhalis.

Incidence, distribution, and outcome of episodes of infection in 100 orthotopic liver transplantations.

Of 83 patients who underwent 100 orthotopic liver transplantations, 53 had a single transplant procedure and at least 6 months of follow-up. In this main study group of 53 patients, major infections developed in 28 (53%) (a mean of 1.8 major episodes per infected patient). Of 51 major infections, 27 were bacterial, 19 were viral, 3 were protozoan, and 2 were fungal. Of the 27 bacterial infections, 22 (81%) occurred in the first 2 months after transplantation. Of the 40 bacterial isolates in the 27 bacterial infections, gram-positive aerobic bacteria were isolated in 26 (65%), anaerobic bacteria in 8 (20%), and aerobic gram-negative bacteria in 6 (15%). Only 1 of 16 bacteremic episodes was due to a gram-negative aerobic bacterium. Cytomegalovirus (CMV) infection occurred in 30 of the 53 patients (57%) and was symptomatic and invasive in 18. CMV infection was diagnosed a mean of 26 days after transplantation. Infections due to Pneumocystis carinii occurred later (2 to 3 months after transplantation). Death from infection occurred in 4 of the 53 patients (8%). In the group of 16 patients with two or more liver transplantations, fungal infection occurred in 2 and CMV infection in 13. In all 16 patients who underwent more than one liver transplantation, a major infection developed. The observations made in the main study group were consistent with findings in 13 patients with one liver transplantation but less than 6 months of follow-up. Infection is a major complication after liver transplantation, generally occurring in the first 2 months. Our observations suggest that the use of selective bowel decontamination may be associated with a relatively lower incidence of gram-negative aerobic bacterial infections.