Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency in the neonatal period. Small-bowel overgrowth with aerobic gram-negative bacteria has previously been implicated in the development of NEC. This prospective study performed quantitative bacteriology on 422 duodenal aspirates collected from 122 very-low-birth-weight (<1,500-g) newborns, at the time of routine changing of nasogastric tubes. Isolates of Enterobacteriaceae were typed by repetitive extragenic, palindromic PCR and pulsed-field gel electrophoresis. One or more samples from 50% of these infants yielded gram-negative bacteria, predominantly Escherichia coli, Klebsiella spp., and Enterobacter spp., with counts up to 108 CFU/g. The proportion of samples with gram-negative bacteria increased with postnatal age, while the percentage of sterile samples declined. Molecular typing revealed marked temporal clustering of indistinguishable strains. All infants had been fed prior to isolation of gram-negative organisms. Antibiotic use had no obvious effect on colonization with Enterobacteriaceae. There were 15 episodes of suspected NEC (stage I) and 8 confirmed cases of NEC (2 stage II and 6 stage III) during the study period. Duodenal aspirates were collected prior to clinical onset in 13 episodes of NEC. Seven of these yielded Enterobacteriaceae...
Between 1983 and 1994, 13 phenotypically similar unidentified clinical isolates were received by the Special Bacteriology Reference Laboratory, Centers for Disease Control and Prevention (CDC). Sources included blood (four strains), lung (three strains), knee fluid and duodenal tissue (one strain each), bone, and lymph node tissue (two strains each). All were aerobic glucose-oxidizing, slender, long, curved gram-negative rods that utilized xylose, sucrose, and maltose; did not grow on MacConkey agar in 1 to 2 days; were oxidase positive; hydrolyzed esculin; and grew on Campylobacter selective medium. All were negative for urease, indole, nitrate reduction, and gelatin hydrolysis. All were motile by means of a single polar flagellum with a noticeably short wavelength; however, motility was sometimes difficult to demonstrate. The cellular fatty acid compositions of these strains, as analyzed by gas-liquid chromatography, were unique, characterized by relatively large amounts of 16:1ω7c, 16:0, and 18:1ω7c with smaller amounts of 12:0, 3-OH-12:1, 14:0, 15:0, 18:0, Br-19:1, and 19:0cyc11–12. High-performance liquid chromatography and mass spectrometry of the quinone extracts of three representative strains showed ubiquinone-10 as the major component. Based on the breakpoints for the family Enterobacteriaceae...
By DNA-DNA hybridization on microplates, we identified 1,230 strains of staphylococci from human clinical specimens and determined the distribution of species. The 10 Staphylococcus species isolated most often were S. epidermidis (31.3%), S. aureus (23.3%), S. haemolyticus (12.2%), S. caprae (10.7%), S. simulans (4.4%), S. hominis (4.0%), S. capitis (3.9%), S. saprophyticus (3.6%), S. warneri (2.2%), and S. lugdunensis (1.3%). From these results, we realized that S. caprae strains were widely distributed in human clinical specimens. The description in Bergey’s Manual of Systematic Bacteriology indicates that no strains of S. caprae produce acid from fructose and mannitol, but all our S. caprae strains produced acid from fructose and mannitol. Consequently, many strains of S. caprae isolated from human clinical specimens have been misidentified as S. haemolyticus or S. hominis by conventional biochemical tests. In this paper, we propose an emended description of S. caprae.
The microscopic examination of Gram-stained sputum specimens is very helpful in the evaluation of patients with community-acquired pneumonia and has also been recommended for use in cystic fibrosis (CF) patients. This study was undertaken to evaluate that recommendation. One hundred one sputum samples from CF patients were cultured for gram-negative bacilli and examined by Gram staining for both sputum adequacy (using the quality [Q] score) and bacterial morphology. Subjective evaluation of adequacy was also performed and categorized. Based on Q score evaluation, 41% of the samples would have been rejected despite a subjective appearance of purulence. Only three of these rejected samples were culture negative for gram-negative CF pathogens. Correlation between culture results and quantitative Gram stain examination was also poor. These data suggest that subjective evaluation combined with comprehensive bacteriology is superior to Gram staining in identifying pathogens in CF sputum.
A medium composed of nutrient broth, 1.8% boric acid, and 1% sodium chloride at pH 7.0 was shown to maintain the stability of Escherichia coli cultures for up to 10 days at room temperature. By using this preservation medium for preparing a simulated sample a successful proficiency test survey in water bacteriology was conducted.
This report presents a summary and analysis of data from the Centers for Disease Control performance evaluation program in bacteriology for the 6-year period 1980 to 1985. During this period, the number of laboratories enrolled in the program ranged from about 750 to 1,000. Identification results reported by participating laboratories for representative species of six major groups of bacteria were placed into five response categories that were based on the level and accuracy of the identifications. Data on the performance of participants with bacterial groups and performance with selected species within each major group were analyzed. Overall, participants experienced the least difficulty in identifying species or serogroups of members of the gram-positive and gram-negative cocci. Participants encountered greater difficulties with anaerobes, gram-positive bacilli, and miscellaneous gram-negative bacteria. Identification of members of the family Enterobacteriaceae was of moderate difficulty. Problems in identifying certain bacterial species were probably related to a number of factors such as the characteristics of the species, its frequency of occurrence, the state of technology available for identification, and the state of proficiency and quality control in individual laboratories at the time of testing. Examples are given of improvements over time in the identification of certain bacterial species. Laboratories participating in an external proficiency testing program should take full advantage of the benefits of participation by instituting measures to correct testing deficiencies identified by the program.
The conjunctivas of 273 inflamed eyes were cultured by both aerobic and anaerobic techniques. Isolations were obtained from 267 (97.8%) of the eyes. Aerobic organisms were isolated from 237 (86.8%) of the conjunctivas. Staphylococcus aureus from 63 (23.1%) of the diseased eyes was the aerobic pathogen most often isolated. Anaerobic bacteria were isolated from 172 (63.0%) of the conjunctivas. Propionibacterium acnes was isolated from 126 (46.2%) of the conjunctivas, and Peptostreptococcus species were isolated from 80 (29.3%) of the conjunctivas. Comparison with the bacteriology of 96 normal eyes showed that anaerobes play a much greater role as etiological agents of conjunctivitis than formerly believed. When anaerobic bacteria were isolated, they appeared on the average in 7 days, indicating that they may be missed by ordinary bacteriological culturing.
The morphological and physiological characteristics of 20 strains of motile, gram-negative, yellow-pigmented oxidative bacilli (groups VE-1 and VE-2) isolated in clinical bacteriology are described. Electron micrographs demonstrate the polar multitrichous flagella of group VE-1 and polar monotrichous flagella of group VE-2. Data obtained from guanine plus cytosine ratio studies of 56.8% for VE-1 and 68.9% for VE-2 distinguish the two groups of bacteria.
Human contact with bears has become more frequent, as has the resultant bear maulings and bite injuries. We report the bacteriology of a patient bitten by a grizzly bear (Ursus arctos) from the Rocky Mountains foothills area east of Banff National Park, Alberta, Canada. The patient received field care, including metronidazole and cefazolin. Subsequent deep-wound cultures grew Serratia fonticola, Serratia marcescens, Aeromonas hydrophila, Bacillus cereus, and Enterococcus durans but no anaerobes.
A system for the automatic capture and retrieval of information contained in routine bacteriology reports is described. The system depends on the preparation of reports on an electric typewriter producing punched paper tape as a byproduct.
AIM--To develop an internal quality assessment (IQA) scheme in a clinical bacteriology laboratory. METHODS--Over 24 months, 1230 diagnostic specimens, representing 0.42% of laboratory workload, were anonymised and resubmitted for analysis. Six hundred and twenty one (48.7%) of these gave positive culture results; 44 fecal and upper respiratory specimens were "spiked" (artificially inoculated) to increase the proportion of positive samples. RESULTS--Discrepancies between IQA and clinical sample results occurred in 188 cases (14.8%): 76.6% of these were in culture results, 13.3% in microscopy performance, and 10.1% in clerical recording. The culture discrepancy rate for each positive sample was lowest for wound (17.5%) and urine (18.1%) specimens, and highest for faeces (34.9%) and upper respiratory (37.7%) samples. Discrepancies in several areas responded to staff training and improvement in technical methods. CONCLUSIONS--An IQA programme of this type assesses the reproducibility of tests within a diagnostic laboratory when analysing common specimen types and organisms. It permits blind assessment of many areas of diagnostic work that are not readily amenable to other quality assurance methods, and it raises the awareness of all staff to the importance of quality in every aspect of specimen and data processing.
The etiological agent most commonly associated with bacillary dysentery is Shigella. As part of its mandate, the Bacteriology and Enteric Disease Program of Health Canada identifies and serotypes unusual isolates of Shigella received from provincial laboratories of public health. In this report, six unusual isolates from three provinces were analyzed biochemically and serologically using slide and tube agglutinations and molecularly using standard pulsed-filed gel electrophoresis (PFGE), PCR, and PCR-restriction fragment length polymorphism (RFLP) techniques. All six isolates were identical. PFGE analysis grouped these strains; biochemically, they were mannitol negative and consistent with the profile of Shigella. Serologically, these strains produced weak reactions in Shigella dysenteriae serovars 4 and 16 and Escherichia coli O159 and O173 antisera. Molecular serotyping by PCR-RFLP of the rfb gene produced an S. dysenteriae serovar 2/E. coli O112ac pattern. They were positive by PCR for ipaH and ial enteroinvasive genes but negative for all other genes tested. Antiserum was prepared from one of the isolates and tested against Shigella and E. coli reference strains as well as the other isolates. The antiserum reacted with the five remaining isolates and showed cross-reactivity with S. dysenteriae serovars 1...
The bacteriology of the gastrointestinal tract is rapidly changing in laboratory techniques and clinical correlations. The flora is found to be very complex, predominantly anaerobic, and importantly dependent on diet. An etiologic role for colon bacteria in colon cancer is suggested by correlations between epidemiologic data and prevalent dietary patterns and stool culture findings. Cultures from aspiration pneumonia, subphrenic abscess, and other intra-abdominal sepsis all yield anaerobes, and for best results antibiotic therapy should combat them as well as aerobes.
A computer system for reporting and recording all specimens processed by the routine bacteriology laboratory at the Royal Postgraduate Medical School is described. Features of interest are the method of input using a mixture of 3-character alphanumeric codes and numbers, cumulative reporting to the wards, and selective listing of relevant previous results for the patient, which is available to technical and supervisory staff during processing of the specimen. The relative value to the wards and the laboratory of each type of information transfer has been assessed. Overall the use of a computer has resulted in higher quality bench work and more accurate reporting. It seems little more expensive than a previous manual system, although it has transferred work from the technical to the clerical staff.
Aspirates from 26 acutely and 17 chronically infected ethmoid sinuses were studied. Thirty-seven aerobes and 10 anaerobes were recovered from isolates from patients with acute sinusitis. Streptococcus pneumoniae and Haemophilus influenzae were predominant. Twenty-seven aerobes and 41 anaerobes were found in isolates from patients with chronic sinusitis. The predominant isolates were anaerobic gram-negative bacilli and Peptostreptococcus spp.
BACKGROUND: It has been established that lack of circumcision increases the risk of urinary tract infection in infants. During the first six months, the presence of foreskin is associated with a greater quantity and a higher concentration of uropathogens in the periurethral area. Very little is known about this association in older males. OBJECTIVE: To compare the periurethral bacteriology of uncircumcised healthy males of more than one year of age. METHODS: The periurethral area of 125 uncircumcised and 46 circumcised healthy males (mean age, 26.5 and 28.3 years, respectively) was swabbed and cultured for facultative and anaerobic bacteria, genital mycoplasmas and Chlamydia trachomatis. RESULTS: Facultative Gram positive cocci predominated in both groups (62% and 80%, respectively). Pure culture of facultative Gram negative rods was more common in uncircumcised males (17% v 4% in circumcised males, p = 0.01). Streptococci, strict anaerobes and genital mycoplasmas were found almost exclusively in uncircumcised males of more than 15 years of age. No case of C trachomatis was identified. CONCLUSIONS: The higher prevalence of potential uropathogens in the subpreputial space is in accordance with a previous finding of increased risk of urinary tract infection in uncircumcised young men. Our results also support the role of the prepuce as a reservoir for sexually transmitted organisms.
Cat scratch disease (CSD) is mostly due to Bartonella henselae after inoculation of the organism through a skin injury. Since the causative bacteria cannot be easily cultured from human lymph node samples, the diagnosis usually relies on epidemiological, clinical, histological, and serological criteria (classical criteria). A study was performed to determine the diagnostic value of PCR analysis for the detection of B. henselae for the diagnosis of CSD and its place in the diagnostic strategy alongside the classical criteria. Over a 7-year period, lymph node biopsy specimens or cytopunctures from 70 patients were systematically tested by PCR for the presence of B. henselae DNA (htrA gene) in the Bacteriology Laboratory of the Hôpitaux Universitaires de Strasbourg. Serological testing by an immunofluorescence assay for B. henselae antibodies was also performed for each patient, and clinical, epidemiological, and histological data were collected. The patients were then divided into two groups according to the number of positive diagnostic criteria for CSD: 29 patients with definite CSD (two or more classical criteria) and 15 patients with possible CSD (less than two classical criteria). The remaining 26 patients for whom another diagnosis was retained were used as a control group. Among all criteria...
Group B streptococcus (GBS) is a major cause of serious infections in neonates. The 2002 revised guidelines of the Centers for Disease Control and Prevention (CDC) for the prevention of perinatal GBS disease recommend that all pregnant women be screened for GBS carriage at between 35 and 37 weeks of gestation and that intrapartum antibiotic prophylaxis be given to carriers. We studied the performances of four different GBS detection assays in the context of antenatal screening. Between May and August 2004, the 605 vaginorectal swab specimens received at our bacteriology laboratory for GBS antenatal detection were tested by the four assays. The standard culture method was done according to the CDC recommendations. The three experimental assays performed with the growth from the selective enrichment (LIM) broth (Todd-Hewitt broth with 15 μg/ml nalidixic acid and 10 μg/ml colistin) after overnight incubation were a GBS antigen detection assay (PathoDx) and two PCR assays (for cfb and scpB). The most accurate assay was the scpB PCR (sensitivity, 99.6%; specificity, 100%), followed by the cfb PCR (sensitivity, 75.3%; specificity, 100%), GBS antigen detection (sensitivity, 57.3%; specificity, 99.5%), and standard culture (sensitivity, 42.3%; specificity...
Partners In Health (PIH) and its sister organization in Lima, Peru, Socios En Salud (SES), treat a majority of multidrug-resistant tuberculosis (MDR-TB) patients in Peru, in conjunction with the Peruvian National TB Program (NTP). Monthly bacteriology tests, which must be collected from health establishments located across this major city, are an integral part of this treatment. Currently, a SES employee visits each health establishment to collect this information by hand, process it and type it into an electronic medical record system (PIH-EMR).
As part of a United States-based multicenter clinical trial, conducted from 2001 to 2004, that compared ertapenem to piperacillin-tazobactam for the treatment of moderate-to-severe diabetic foot infections (DFIs), we obtained 454 pretreatment specimens from 433 patients. After debridement, the investigators collected wound specimens, mostly by curettage or biopsy, and sent them to the R. M. Alden Research Laboratory for aerobic and anaerobic culture. Among the 427 positive cultures, 83.8% were polymicrobial, 48% grew only aerobes, 43.7% had both aerobes and anaerobes, and 1.3% had only anaerobes. Cultures yielded a total of 1,145 aerobic strains and 462 anaerobic strains, with an average of 2.7 organisms per culture (range, 1 to 8) for aerobes and 2.3 organisms per culture (range, 1 to 9) for anaerobes. The predominant aerobic organisms were oxacillin-susceptible Staphylococcus aureus (14.3%), oxacillin-resistant Staphylococcus aureus (4.4%), coagulase-negative Staphylococcus species (15.3%), Streptococcus species (15.5%), Enterococcus species (13.5%), Corynebacterium species (10.1%), members of the family Enterobacteriaceae (12.8%), and Pseudomonas aeruginosa (3.5%). The predominant anaerobes were gram-positive cocci (45.2%), Prevotella species (13.6%)...