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Biomedical subjects

M M McNeil

Publications and source records attributed to M M McNeil.

At least 55 records · Page 3Linked to original sources
PubMed1993

Cutaneous Nocardia farcinica infection in a nonimmunocompromised patient: case report and review.

Nocardia farcinica, the etiologic agent of bovine farcy, is microbiologically related to but distinct from Nocardia asteroides. N. farcinica is noted for its propensity to cause serious systemic infection in both normal and immunocompromised hosts and its marked degree of resistance to multiple antimicrobial agents. We present a case in which a nonimmunocompromised patient who sustained a contaminated facial laceration developed an abscess due to N. farcinica with underlying osteomyelitis. The severity of the infection necessitated surgical debridement followed by administration of intravenous amikacin therapy. The isolate was susceptible to amikacin and trimethoprim-sulfamethoxazole but resistant to erythromycin in vitro. Therapy with trimethoprim-sulfamethoxazole was started but was discontinued because of the patient's intolerance to the drug. Intramuscular amikacin was substituted, resulting in complete resolution of the infection. The history, epidemiology, and microbiological characteristics of this interesting and unusual microorganism are reviewed.

Abscess↗
PubMed1993

Rhodococcus species fatal infection in an immunocompetent host.

A 24-year-old woman had fatal pneumonia-associated adult respiratory distress syndrome caused by Rhodococcus species. Histological examination of lung biopsy tissue showed intracellular coccobacillary microorganisms. Antimicrobial susceptibility tests on the patient's blood isolate showed that it was resistant to clindamycin and norfloxacin but susceptible to several other antimicrobial agents. Also, the isolate's biochemical reactions and pattern of RNA gene-containing restriction fragments were significantly different from those of the 20 recognized Rhodococcus species, suggesting that this patient's infection was caused by an as yet uncharacterized Rhodococcus species. Of the 17 human cases of nonequi Rhodococcus species infection reported to date (including the current case), nine patients were immunocompetent, five had disseminated infection, and four died. Further studies will be required to unequivocally establish the species status of this patient's Rhodococcus isolate biochemically and genetically.

Actinomycetales Infections↗
PubMed1992

Aspergillus fumigatus sternal wound infections in patients undergoing open heart surgery.

During a 21-month period (July 1986-April 1988), six patients who underwent open heart surgery at Holston Valley Hospital and Medical Center in Kingsport, Tennessee, developed sternal would infections caused by Aspergillus fumigatus. All patients required sternectomy, reconstructive surgery, and long term amphotericin B therapy; no patient died. By univariate analysis, the following were significantly associated with A. fumigatus sternal would infection: chronic lung disease, a recent history of pneumonia, a greater mean number of admission diagnoses, and a particular surgeon. However, multivariate analysis identified chronic lung disease as the only independent risk factor and the best predictor of A. fumigatus sternal wound infections. No factors related to the surgical procedure or operating room personnel were associated with infection. A review of the characteristics of the patients undergoing open heart surgery showed that since 1985, there had been a trend for these patients at Holston Valley Hospital and Medical Center to be older and sicker, which may have contributed to the occurrence of infections never observed before. Despite an extensive investigation, no environmental source for A. fumigatus was identified. A. fumigatus, however, grew from the bronchial washing of one patient at the time the sternal wound infection was diagnosed, and a prospective study showed that the rate of A. fumigatus colonization among open heart surgery patients was the same as the rate of sternal wound infections caused by A. fumigatus. These data suggest that patients with chronic lung disease and respiratory colonization with A. fumigatus are at increased risk for A. fumigatus sternal wound infections after open heart surgery.

Aged↗
PubMed1992

Distribution and antimicrobial susceptibility of Rhodococcus equi from clinical specimens.

Rhodococcus equi, an unusual gram positive aerobic actinomycete, was first described as a respiratory pathogen of livestock in 1923. Reports of human clinical illness have emphasized R. equi as a cause of invasive pulmonary infection in severely immunocompromised patients and, recently, have implicated it as a cause of pneumonia, bacteremia and disseminated infection in HIV-infected patients. To determine the distribution of R. equi we evaluated 107 isolates referred to the Centers for Disease Control (CDC) during the period January 1973 through December 1990. The sites of these 107 isolates (101 patient and 6 animal isolates) were: blood (32 isolates), sputum (30), lung tissue (13) and other site (32). Before 1983, when the first R. equi isolate from an HIV-infected patient was received, CDC received a total of 52 patient isolates. In addition, during this 10 year period, R. equi isolates were received from more than one site from only one patient. However, during the two year period 1989-1990, we identified 8 patients with underlying HIV infection and R. equi pneumonia who accounted for 29 of 35 (83%) R. equi patient isolates; 6 of these patients also had bacteremia and three died with disseminated R. equi infection. No isolates were resistant to amoxicillin-clavulanate, ampicillin-sulbactam, gentamicin or imipenem, and few (less than 5%) isolates were resistant to erythromycin, rifampin, tetracycline, and trimethoprim-sulfamethoxazole. These results suggest that HIV-infected patients, in particular, are predisposed to develop invasive pulmonary, fatal disseminated R. equi infection (or both), and appropriate antimicrobial susceptibility testing of clinical isolates may improve the effectiveness of therapy of R. equi-infected patients.

Actinomycetales Infections↗
PubMed1992

Infections due to Nocardia transvalensis: clinical spectrum and antimicrobial therapy.

Nocardia transvalensis, a rare Nocardia species, has previously been recognized as a cause of actinomycotic mycetoma. In a retrospective review of N. transvalensis isolates referred to the Centers for Disease Control (Atlanta) during the period January 1981 through January 1990, we identified 15 patient isolates. Four N. transvalensis isolates originated from one Australian reference laboratory; one patient's isolate that was identified by the Australian laboratory but that was not received at the Centers for Disease Control was also included in our study. A review of the cases of these 16 patients found that N. transvalensis caused infection in 10 patients and colonization in two patients. Six (75%) of eight patients with primary pulmonary or disseminated N. transvalensis infections had an underlying immunologic disorder or were receiving immunosuppressive therapy; three patients with disseminated infection died. All nine infected patients for whom specific antimicrobial therapy was prescribed received trimethoprim-sulfamethoxazole. Results of in vitro antimicrobial susceptibility tests of 11 N. transvalensis isolates revealed increased antimicrobial resistance to amikacin and other drugs when compared with that of other Nocardia species. Severely immunocompromised patients are predisposed to N. transvalensis pneumonia or disseminated infection, and the lung may be the portal of entry.

Adolescent↗
PubMed1992

Central venous catheter sepsis caused by unusual Gordona (Rhodococcus species: identification with a digoxigenin-labeled rDNA probe.

We describe central line sepsis caused by Gordona (Rhodococcus) species in two patients, which complicated receipt of long-term total parenteral nutrition at home. Species identification was attempted by conventional biochemical analysis and analysis of polymorphisms in the ribosomal RNA genes with use of a digoxigenin-labeled rDNA probe. Using these techniques, we identified our first patient's isolate as Gordona terrae. The isolate from our second patient was biochemically atypical and could not be reliably matched to any of the recognized Gordona (Rhodococcus) species. To our knowledge, these patients are the first to have been reported with systemic infection caused by Gordona (Rhodococcus) species. The first patient's infection resolved after 6 weeks of intravenous therapy with vancomycin with the catheter left in situ; however, infection in the second patient required catheter removal for cure. These cases show that immunocompetent patients receiving long-term parenteral nutrition may develop central line infections with these unusual species of microorganisms.

Actinomycetales Infections↗
PubMed1992

Outbreak of pseudoinfection with Tsukamurella paurometabolum traced to laboratory contamination: efficacy of joint epidemiological and laboratory investigation.

From January 1988 to May 1989, one hospital in South Carolina reported 12 isolates of Tsukamurella paurometabolum from 10 patients. There were no common risk factors among the patients. Case-control studies revealed that the positive specimens were significantly more likely to have been processed in the TB/fungal room, to have been tissue samples, and to have been handled by one technician. Typing on the basis of biochemical, antimicrobial resistance, Southern blot, and ribotype profiles showed that the isolates from the outbreak were essentially identical and that they were distinguishable from each of two isolates obtained after the outbreak and from two type strains. These findings support the hypothesis of a common-source outbreak of pseudoinfection. There are reasons to believe that T. paurometabolum is present both in the environment and as a culture contaminant more often than has been recognized and that it is very rarely the true cause of infection in humans. Typing results show differences between one type strain and all of the other isolates studied in terms of colonial morphology, biochemistry, antimicrobial susceptibility, and ribotyping; these differences suggest that the nomenclature of T. paurometabolum may require further clarification.

Actinomycetales↗
PubMed1992

Identification and epidemiological typing of clinical and environmental isolates of the genus Rhodococcus with use of a digoxigenin-labeled rDNA gene probe.

Rhodococcus species are ubiquitous in the environment, and several species have been reported to have pathogenic potential for humans. Rhodococcus equi, in particular, has been reported to cause infections in patients with AIDS. However, the identification of Rhodococcus species with use of conventional biochemical tests is problematic, and no simple and reproducible method exists for their rapid identification and differentiation. We found that the type strains of the 20 recognized species in the genus Rhodococcus could be clearly distinguished with use of a combination of the Pvu II and Pst I rRNA gene restriction endonuclease patterns and a digoxigenin-labeled Escherichia coli rDNA probe. Analysis of four clinical or environmental isolates confirmed as Rhodococcus bronchialis showed no interstrain variation of rRNA gene bands. Analysis of 15 isolates confirmed as R. equi from 13 patients showed 11 different rRNA gene patterns. No discernible difference was observed in the ribotype patterns between R. equi isolates from patients for whom AIDS had been diagnosed and those from patients who did not have AIDS, and there was no evidence of geographic clustering of R. equi ribotype patterns. Three of five Rhodococcus species isolates that could not be differentiated with use of conventional biochemical methods were identified with use of ribotype analysis. Therefore, ribotype analysis may provide an important adjunct to current biochemical identification of environmental and clinical isolates of Rhodococcus species.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Disseminated Nocardia transvalensis infection: an unusual opportunistic pathogen in severely immunocompromised patients.

Nocardia infections are infrequently recognized in humans. Nocardia species may cause severe life-threatening infections among immunocompromised patients and have been reported to cause actinomycotic mycetomas, primarily in tropical areas. Two severely immunocompromised patients had disseminated N. transvalensis infections. One had underlying X-linked variant chronic granulomatous disease and died of disseminated N. transvalensis infection, which was diagnosed only at postmortem examination. The second patient developed N. transvalensis pneumonia within 3 months of undergoing renal transplantation and died of disseminated mixed Pseudallescheria boydii and N. transvalensis infections. Thus, N. transvalensis may cause invasive and potentially fatal pulmonary and disseminated infections. Accordingly, clinical microbiology laboratories should become proficient in identifying this uncommon aerobic actinomycete.

Adult↗
PubMed1992

Nonmycetomic Actinomadura madurae infection in a patient with AIDS.

Actinomadura madurae is an aerobic actinomycete which is best known worldwide as the cause of actinomycotic mycetomas. It has not previously been reported to have caused invasive pulmonary or disseminated infection in humans. We describe an AIDS patient with opportunistic A. madurae-induced pneumonia and bacteremia. The isolate from the patient's blood was subjected to dilutional antimicrobial susceptibility tests with 12 antimicrobial agents and was found to have a wide spectrum of susceptibility. This unusual microorganism may be a cause of infections in severely immunosuppressed patients.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Pseudoepidemic of Nocardia asteroides associated with a mycobacterial culture system.

Nocardia isolations increased from 0.7 to 11.7/1,000 acid-fast bacillus and mycological cultures (P less than 0.000001). Only three isolations from one patient represented infection. Pseudoepidemic strain identity was confirmed by DNA fingerprinting; the isolate causing infection was distinct. The end of the pseudoepidemic was associated with changing the needle sterilizer and prolonging needle sterilization time on the BACTEC 460 machine. To our knowledge, this is the first reported Nocardia asteroides pseudoepidemic.

Cross Infection↗
PubMed1992

Rhodococcus equi cavitary pneumonia in HIV-infected patients: an unsuspected opportunistic pathogen.

Two patients seropositive for human immunodeficiency virus (HIV) and with no previous acquired immunodeficiency syndrome-defining conditions developed cavitary pneumonia and pleural disease caused by Rhodococcus equi. R. equi was isolated from these patients' sputum and lung biopsy specimens, respectively, but the microorganism was initially considered to be a contaminant (patient 1) or misidentified as a nontuberculous mycobacterium (patient 2). The R. equi infection was fatal in one patient, who died after 4 months without specific antimicrobial therapy; the second patient was unresponsive to combination therapy with various antimicrobial agents. R. equi may cause life-threatening infections in HIV-infected patients. Microbiology laboratories should be cognizant of the need to exclude R. equi as a cause of infection in highly immunosuppressed patients.

AIDS-Related Opportunistic Infections↗
PubMed1991

Microbial growth and endotoxin production in the intravenous anesthetic propofol.

OBJECTIVE: In this study, we measured microbial growth and endotoxin production in the intravenous anesthetic propofol using 10 different microbial strains; 6 isolated from outbreak cases and 4 from laboratory stock cultures. DESIGN: In each trial, endotoxin-free glass tubes containing 10 ml propofol were inoculated with 10(0)-10(3) CFU/ml of the test organism and incubated at 30 degrees C for 72 hours. SETTING: In May and June 1990, the Centers for Disease Control received reports of 5 outbreaks in 5 states of postsurgical patient infections and/or pyrogenic reactions. Epidemiologic and laboratory investigations implicated extrinsic contamination of an intravenous anesthetic, propofol, as the probable source of these outbreaks. RESULTS: After 24 hours, 9 of the 10 cultures increased in viable counts by 3 to 6 logs. At least 1 ng/ml of endotoxin was produced within 24 hours by Escherichia coli, Enterobacter cloacae, and Acinetobacter calcoaceticus subspecies anitratus. CONCLUSIONS: Propofol can support rapid microbial growth and endotoxin production. To avoid infectious complications, scrupulous aseptic technique should be used when preparing or administering this anesthetic.

Anesthesia, Intravenous↗
PubMed1990

Mycobacterium gordonae pseudoinfection associated with a contaminated antimicrobial solution.

At Yale-New Haven Hospital, 46 specimens submitted for mycobacterial culture during an 8-week period in 1989 were positive for Mycobacterium gordonae, a nontuberculous acid-fast bacterium (AFB) of low pathogenicity. The specimens were submitted from 34 patients who came from various inpatient and outpatient services. Four patients were begun on antimycobacterial therapy on the basis of an AFB isolate which was later identified as M. gordonae. Isolation of M. gordonae was associated with use of the BACTEC TB system (BACTEC TB; Becton Dickinson Diagnostic Instrument Systems, Towson, Md.) and an antimicrobial solution, BACTEC PANTA PLUS (PANTA; Becton Dickinson Diagnostic Instrument Systems). The manufacturer reported that two lots (B9K1 and C9K1) of PANTA kits containing a single production lot (N8C1) of PANTA, which had been shipped to 173 laboratories, had been contaminated with M. gordonae. A survey of mycobacteriology laboratories in the United States revealed that, during April to July 1989, the M. gordonae isolation rate was 5.8/1,000 AFB specimens processed at laboratories that did not use BACTEC TB, 11.4/1,000 AFB specimens at laboratories that used BACTEC TB but not the implicated lot of PANTA, and 23.5/1,000 AFB specimens at laboratories that used BACTEC TB and the lot of implicated PANTA. Intrinsic contamination of PANTA was attributed to ineffective sterilization of water used in the manufacturing process and was not detected prior to product shipment because cultures for AFB were not part of the quality control regimen. This episode emphasizes that clinical laboratories can detect pseudoepidemics promptly if they are alert to abrupt increases in isolation rates, especially of unusual or generally nonpathogenic organisms.

Anti-Bacterial Agents↗
PubMed1990

Oerskovia xanthineolytica implicated in peritonitis associated with peritoneal dialysis: case report and review of Oerskovia infections in humans.

Oerskovia species are nocardialike bacteria that have been implicated as pathogens only rarely. These organisms are branched, gram-positive bacilli that are oxidase negative, catalase positive, and non-acid fast. Unlike Nocardia species, these organisms are motile, do not produce aerial mycelia, and possess a cell wall with large amounts of galactose. Colonies are bright yellow and produce branched vegetative hyphae on nutrient agar. A 70-year-old patient undergoing chronic ambulatory peritoneal dialysis for end-stage renal dysfunction developed recurrent peritonitis. Five peritoneal fluid cultures and one catheter specimen obtained over a period of two weeks yielded a gram-positive bacillus; Oerskovia xanthineolytica was isolated from all six cultures. Prolonged systemic therapy with gentamicin and vancomycin was unsuccessful in curing the peritonitis, but the infection resolved following removal of the peritoneal catheter. This is the first reported case of peritonitis associated with this microorganism. A review of previously described Oerskovia infections, most of which were associated with foreign bodies, showed that removal of infected foci was usually necessary for cure.

Actinomycetales↗