Search

Clostridium difficile is the most common cause of health care-associated diarrhea. Accurate and rapid diagnosis is essential to improve patient outcome and prevent disease spread. We compared our two-step diagnostic algorithm, an enzyme immunoassay for glutamate dehydrogenase (GDH) followed by the cytotoxin neutralization test (CYT) with a turnaround time of 24 to 48 h, versus the Cepheid Xpert C. difficile Epi assay, a PCR-based assay with a turnaround time of <1 h. In the first phase of the study, only GDH-positive stool samples were tested by both CYT and Xpert PCR. Discordant results were resolved by toxigenic culture. In the second phase, all stool samples were tested by GDH and Xpert PCR. Only GDH-positive stools were further tested by CYT. Genotypic characterization of 45 Xpert PCR-positive stools was performed by sequencing of the tcdC gene and PCR ribotyping. In phase 1, the agreement between the GDH-CYT and the GDH-Xpert PCR was 72%. The sensitivities and specificities of GDH-CYT and GDH-Xpert PCR were 57% and 97% and 100% and 97%, respectively. In phase 2, the agreement between GDH-CYT and Xpert PCR alone was 95%. As in phase 1, sensitivity of the Xpert PCR was higher than that of the GDH-CYT. The correlation between PCR-ribotyping, sequencing, and Xpert PCR for detection of NAP1 strains was excellent (>90%). The excellent sensitivity and specificity and the rapid turnaround time of the Xpert PCR assay as well as its strain-typing capability make it an attractive option for diagnosis of C. difficile infection.

The role of the species Mycobacterium haemophilum as a pathogenic non-tuberculous microorganism is becoming better defined with the use of specific detection methods. However, epidemiological investigations of this species are still scarce. We analysed the genetic diversity of M. haemophilum by amplified fragment length polymorphism (AFLP) typing and compared isolates from different parts of the world. In total, 128 isolates, including 41 from the USA, 51 from Australia, 28 from Europe and eight from Israel were compared using AFLP methodology. Two restriction enzymes (MseI and EcoRI) and one selective primer were applied and provided a high discriminatory power. Clusters of isolates with identical AFLP patterns, which could indicate a possible common source, were observed from the Netherlands, New York and Australia. No clear clustering on the basis of continental origin was observed; however, types were restricted to geographical areas and not found on other continents. A high genetic stability within the species was demonstrated by the long-term existence of a single type.

We report here the use of novel "sloppy" molecular beacon probes in homogeneous PCR screening assays in which thermal denaturation of the resulting probe-amplicon hybrids provides a characteristic set of amplicon melting temperature (T(m)) values that identify which species is present in a sample. Sloppy molecular beacons possess relatively long probe sequences, enabling them to form hybrids with amplicons from many different species despite the presence of mismatched base pairs. By using four sloppy molecular beacons, each possessing a different probe sequence and each labeled with a differently colored fluorophore, four different T(m) values can be determined simultaneously. We tested this technique with 27 different species of mycobacteria and found that each species generates a unique, highly reproducible signature that is unaffected by the initial bacterial DNA concentration. Utilizing this general paradigm, screening assays can be designed for the identification of a wide range of species.

A retrospective analysis of 57 pediatric oncology patients with a baseline positive vancomycin-resistant enterococcus (VRE) culture who subsequently received chemotherapy and/or radiation therapy was performed. The incidence of subsequent VRE infection was calculated using a competing risk analysis accounting for death from non-VRE causes as a competing risk. Ten patients had subsequent VRE infection. The cumulative incidence of subsequent infection was 14% (7-27%, 95% confidence interval) at 1 year and 16% (9-29%, 95% confidence interval) at 2 years. None of the hypothesized risk factors appeared to differ between patients who developed a subsequent infection and those who did not., ((c) 2008 Wiley-Liss, Inc.)

Background: Human metapneumovirus is a recently discovered RNA virus that typically causes respiratory disease in children. It has been linked to severe lower airway disease in hematopoietic stem cell and solid-organ transplant recipients. hMPV infection in a large population of patients with underlying cancer and varying degrees of immunosuppression has not been reported. We sought to characterize hMPV infection in patients with cancer., Methods: Review of all cases of hMPV infection from two seasons (2005-6 and 2006-7) detected by DFA and/or real-time PCR at MSKCC, a tertiary cancer center in New York City., Results: Among MSKCC patients with cancer, 51 (2.7%) of 1899 patients were positive for hMPV, including 3.2% with hematologic neoplasm and 1.7% with solid tumors. More children (4.5%) were positive than adults (2.2%). PCR detected twice as many cases as DFA. Cough and fever were common complaints. The longest shedding period was 80 days. 40 patients received radiographic evaluation; of these, 22 showed abnormalities including patchy (11), ground glass (5), and interstitial infiltrates (4)., Conclusions: hMPV causes a nonspecific respiratory illness and was found in more than 2% of all tested persons with cancer. PCR detected substantially more cases than DFA. Unlike previous reports, we observed no fatalities due to hMPV, including 22 HSCT recipients with the infection.

Objective: To analyze cases of bacterial and fungal meningitis in patients with cancer., Methods: Retrospective chart review from 1993 to 2004 was performed of patients with cancer at our institution who had positive CSF bacterial or fungal culture., Results: We identified 312 positive CSF cultures representing 175 unique presentations. Ninety-six cultures were deemed contaminants, leaving 79 cultures for analysis in 77 patients; 78% had prior neurosurgery. Organisms included 68% gram-positive cocci, 10% gram-positive bacilli, 14% gram-negative bacilli, 7% Cryptococcus, and 1% C. albicans. None had N. meningitidis or H. influenza. Two patients each had S. pneumoniae or L. monocytogenes. Five percent of presentations demonstrated the triad of fever, nuchal rigidity, and mental status changes. Seventy-five percent of presentations demonstrated CSF pleocytosis (> or = 10). Median CSF WBC count was 74 cells/mm(3). CSF protein was elevated and glucose was depressed in 71%. In neutropenic patients (n = 6), 4 had 0 to 1 CSF WBC/mm(3), and 2 had normal CSF. VP shunt infections were more likely to present with mental status changes. Thirty day mortality was 13%., Conclusions: Patients with cancer do not manifest symptoms of meningitis as often as patients without cancer and display a very different set of CSF organisms compared to a general population. The CSF inflammatory response is muted in patients with cancer with meningitis. Most patients with cancer with meningitis have had prior neurosurgery. Additionally, the organisms causing meningitis in the cancer population have shifted over time, with a decline in the organisms which typically infect immunocompromised hosts and an increase in gram-positive infections.

An unknown virus was isolated from a lung biopsy sample and multiple other samples from a patient who developed a lethal case of pneumonia following a peripheral blood stem cell transplant. A random PCR-based molecular screening method was used to identify the infectious agent as avian paramyxovirus 1 (APMV-1; a group encompassing Newcastle disease virus), which is a highly contagious poultry pathogen that has only rarely been found in human infections. Immunohistochemical analysis confirmed the presence of APMV-1 antigen in sloughed alveolar cells in lung tissue from autopsy. Sequence from the human isolate showed that it was most closely related to virulent pigeon strains of APMV-1. This is the most completely documented case of a systemic human infection caused by APMV-1 and is the first report of an association between this virus and a fatal disease in a human.

Bloodstream infection caused by vancomycin-resistant enterococcus (VRE) is associated with very high mortality among allogeneic hematopoietic stem cell transplant (alloHSCT) recipients. However, it remains unclear whether VRE bloodstream infection directly causes mortality in the early posttransplant period or is simply a marker of poor outcome. To determine the risk factors for VRE bloodstream infection and its effect on outcome, we followed 92 patients screened for stool colonization by VRE upon admission for alloHSCT. Patient records were reviewed to determine outcomes, including mortality and microbiologic failure. Colonization by VRE was extremely common, occurring in 40.2% of patients. VRE bloodstream infection developed in 34.2% of colonized patients by day +35, compared to 1.8% without VRE colonization (P < .01). VRE bloodstream infection was associated with a significant decrement in survival and frequent microbiologic failure, despite treatment with linezolid and/or daptomycin. Five (35.7%) of 14 patients with VRE bloodstream infection had attributable mortality or contributing mortality from the infection. Strain typing by pulsed-field gel electrophoresis identified 9 different VRE strains among the 37 colonized patients and 5 patients with different strains recovered from the stool and the blood. In conclusion, stool screening effectively identified patients at extremely high risk for VRE bloodstream infection. The high mortality of VRE in the early posttransplant period supports the use of empiric antibiotics with activity against VRE during periods of fever and neutropenia in colonized patients.

Hematopoietic stem cell transplant (HSCT) recipients are at risk for Epstein-Barr virus (EBV)-associated, post transplant lymphoproliferative disorder (PTLD). Studies have suggested that early treatment may improve the outcome of patients with PTLD. Thus, significant attention has been focused on PCR-based approaches for preemptive (i.e., prior to clinical presentation) diagnosis. Reports from several transplant centers have demonstrated that HSCT recipients with PTLD generally have higher concentrations of EBV DNA in the peripheral blood than patients without PTLD. However, the PCR values of patients with PTLD typically span multiple orders of magnitude and overlap significantly with values from patients without PTLD. Thus, questions remain about the sensitivity and predictive value of these assays. Preemptive strategies using rituximab and/or EBV-specific cytotoxic T lymphocytes have been evaluated in patients with elevated EBV viral loads. We review the current literature, discuss our institutional experience and identify several areas of future research that could improve the diagnosis and treatment of this life-threatening disorder in HSCT recipients.

We report on bloodstream infection (BSI) rates, risk factors, and outcome in a cohort of 298 adult and pediatric hematopoietic stem cell transplantation (HSCT) recipients at Memorial Sloan-Kettering Hospital from September 1999 through June 2003. Methods. Prospective surveillance study. BSI rates are reported per 10,000 HSCT days. Date of engraftment is defined as the first of at least 3 consecutive dates of absolute neutrophil count >500/mm(3) after stem cell infusion. BSI severity grades: severe (intravenous antibiotics), life threatening (sepsis), or fatal (caused or contributed to death). Results. The incidence of pre- and post-engraftment BSI was 22% and 19.5%, respectively. Pre-engraftment highest rates were observed for viridans streptococci (58), Enterobacteriaceae (39), and Enterococcus faecium (34). Post-engraftment rates ranged from 0.2 to 2.9 without any predominant pathogen. In multivariate analyses, pre-engraftment BSI was associated with diagnosis of chronic myelogenous leukemia, age >18 years and peripheral blood stem cell graft; post-engraftment BSI was associated with acute graft-versus-host disease, neutropenia, and liver or kidney dysfunction. Attributable mortality was 12.5% and 1.7% for pre- and post-engraftment BSI, respectively. BSI fatality rates were 24% for viridans streptococci, 8% for E. faecium, 11% for Staphylococcus aureus, and 67% for Candida. Conclusions. Pre-engraftment BSI, especially by viridans streptococci and E. faecium, was associated with substantial attributable mortality. Post-engraftment BSI was a marker of post-transplant complications and rarely the primary cause of death.

Background: Viridans streptococcal bacteremia (VSB) after allogeneic hematopoietic stem cell transplantation (HSCT) is associated with substantial mortality. Prevention of this serious complication is therefore a high priority. The objective of this study was to evaluate the effect of early vancomycin administration on rates and outcomes of VSB., Methods: We analyzed the effect of early vancomycin on the incidence of VSB in a cohort of 430 consecutive HSCTs performed during the period of 1 January 1998 to 30 September 2002. The primary end point was time to diagnosis of VSB. Early vancomycin was defined as >or=2 doses of vancomycin between days -7 through +7 after HSCT or diagnosis of VSB, whichever occurred first. Risk factors for VSB were identified in univariate and multivariate Cox proportional hazard models., Results: The incidence of VSB in the cohort was 7.4%. The incidence of VSB in patients who did not receive early vancomycin was 24.8%, compared with 0.3% in patients who did (P<.001). Additional risk factors were female sex, conditioning with total body irradiation, and diagnosis of chronic myelogenous leukemia., Conclusions: The attributable mortality rate for VSB in our cohort was 21%. Early vancomycin was associated with decreased VSB (hazard ratio, 0.02; 95% confidence interval, 0.003-0.19) after controlling for age, sex, underlying disease, and transplantation variables. The benefits of vancomycin prophylaxis for the prevention of VSB and associated mortality need to be evaluated in a prospective clinical trial.

We describe a 12-year-old boy with acute myeloid leukemia who developed pleuropericarditis while he was neutropenic and was receiving intravenously administered antibiotic and antifungal therapy for pneumonia. A KOH preparation of the purulent material from an extensive diagnostic and therapeutic pleuropericardial drainage procedure revealed multiple irregularly septate hyphae, and cultures yielded the organism Pythium insidiosum. After completing a 12-month course of intravenously administered liposomal amphotericin B (AmBisome; Fujisawa Healthcare) and itraconazole, the patient remained alive, in clinical remission, and symptom free.

We describe a case of CMV ventriculoencephalitis in a severely immunocompromised bone marrow transplant recipient who was receiving combination therapy with ganciclovir and foscarnet for treatment of viremia and retinitis. Analysis of sequential viral isolates recovered from the patient's cerebrospinal fluid suggested that disease developed because of the presence of viral resistance and, possibly, low tissue penetration of antiviral agents.

Mycobacterium haemophilum, a recently described pathogen, can cause an array of symptoms in immunocompromised patients. To date, 90 patients with this infection have been described worldwide. We report our institution's experience with 23 patients who were treated from 1990 through 2000. Fourteen patients had undergone bone marrow transplantation, 5 were infected with human immunodeficiency virus, 3 had hematologic malignancies, and 1 had no known underlying immunosuppression. Clinical syndromes on presentation included skin lesions alone in 13 patients, arthritis or osteomyelitis in 4 patients, and lung disease in 6 patients. Although patients with skin or joint involvement had favorable outcomes, 5 of 7 patients with lung infection died. Prolonged courses of multidrug therapy are required for treatment. A diagnosis of M. haemophilum infection must be considered for any immunocompromised patient for whom acid-fast bacilli are identified in a cutaneous, synovial fluid or respiratory sample or for whom granulomas are identified in any pathological specimen.

Candida dubliniensis, a germ tube-positive yeast first described and identified as a cause of oral candidiasis in patients with acquired immunodeficiency syndrome in Europe in 1995, has an expanding clinical and geographic distribution that appears to be similar to that of the other germ tube-positive yeast, Candida albicans. This study determined the frequency, clinical spectrum, drug susceptibility profile, and suitable methods for identification of this emerging pathogen at a cancer center in 1998 and 1999. Twenty-two isolates were recovered from 16 patients with solid-organ or hematologic malignancies or acquired immunodeficiency syndrome. Two patients with cancer had invasive infection, and 14 were colonized with fungus or had superficial fungal infection. All isolates produced germ tubes and chlamydospores at 37 degrees C, did not grow at 45 degrees C, and gave negative reactions with d-xylose and alpha-methyl-d-glucoside in the API 20 C AUX and ID 32 C yeast identification systems. Phenotypic identification was confirmed by molecular beacon probe technology. All isolates were susceptible to the antifungal drugs amphotericin B, 5-fluorocytosine, fluconazole, itraconazole, and ketoconazole.

There is a growing need for a more accurate, rapid, and cost-effective alternative to conventional tests for identification of clinical isolates of Mycobacterium species. Therefore, the ability of the Sherlock Mycobacteria Identification System (SMIS; MIDI, Inc.) using computerized software and a Hewlett-Packard series 1100 high-performance liquid chromatograph to identify mycobacteria was compared to identification using phenotypic characteristics, biochemical tests, probes (Gen-Probe, Inc.), gas-liquid chromatography, and, when necessary, PCR-restriction enzyme analysis of the 65-kDa heat shock protein gene and 16S rRNA gene sequencing. Culture, harvesting, saponification, extraction, derivatization, and chromatography were performed following MIDI's instructions. Of 370 isolates and stock cultures tested, 327 (88%) were given species names by the SMIS. SMIS software correctly identified 279 of the isolates (75% of the total number of isolates and 85% of the named isolates). The overall predictive value of accuracy (correct calls divided by total calls of a species) for SMIS species identification was 85%, ranging from only 27% (3 of 11) for M. asiaticum to 100% for species or groups including M. malmoense (8 of 8), M. nonchromogenicum (11 of 11), and the M. chelonae-abscessus complex (21 of 21). By determining relative peak height ratios (RPHRs) and relative retention times (RRTs) of selected mycolic acid peaks, as well as phenotypic properties, all 48 SMIS-misidentified isolates and 39 (91%) of the 43 unidentified isolates could be correctly identified. Material and labor costs per isolate were $10.94 for SMIS, $26.58 for probes, and $42.31 for biochemical identification. The SMIS, combined with knowledge of RPHRs, RRTs, and phenotypic characteristics, offers a rapid, reasonably accurate, cost-effective alternative to more traditional methods of mycobacterial species identification.

In January 1998, an outbreak of influenza A occurred on our adult bone marrow transplant unit. Aggressive infection control measures were instituted to halt further nosocomial spread. A new, more rigorous approach was implemented for the 1998/99 influenza season and was extremely effective in preventing nosocomial influenza at our institution.

Candida dubliniensis is an opportunistic fungal pathogen that has been linked to oral candidiasis in AIDS patients, although it has recently been isolated from other body sites. DNA sequence analysis of the internal transcribed spacer 2 (ITS2) region of rRNA genes from reference Candida strains was used to develop molecular beacon probes for rapid, high-fidelity identification of C. dubliniensis as well as C. albicans. Molecular beacons are small nucleic acid hairpin probes that brightly fluoresce when they are bound to their targets and have a significant advantage over conventional nucleic acid probes because they exhibit a higher degree of specificity with better signal-to-noise ratios. When applied to an unknown collection of 23 strains that largely contained C. albicans and a smaller amount of C. dubliniensis, the species-specific probes were 100% accurate in identifying both species following PCR amplification of the ITS2 region. The results obtained with the molecular beacons were independently verified by random amplified polymorphic DNA analysis-based genotyping and by restriction enzyme analysis with enzymes BsmAI and NspBII, which cleave recognition sequences within the ITS2 regions of C. dubliniensis and C. albicans, respectively. Molecular beacons are promising new probes for the rapid detection of Candida species.

Mycobacterium haemophilum is an emerging pathogen in immunocompromised patients. We report the clinical and histologic findings of 16 skin biopsies from 11 patients with culture-proven infections by M. haemophilum. The patients had leukemia or non-Hodgkin's lymphoma. Ten of them had undergone bone marrow transplantation. When the skin biopsy specimens were taken, a portion of the skin was simultaneously submitted to a microbiology laboratory for cultures. The remaining skin was processed routinely. Acid-fast bacilli were found in 11 of 16 lesions. The number of histologically detectable organisms was typically low: nine biopsies had fewer than three bacilli per 50 oil immersion fields. The most common histologic pattern was a mixed suppurative and granulomatous reaction (7 of 16 biopsies). Four biopsies showed well-formed epithelioid granulomas. Two showed necrosis, one of which was ulcerated. One lesion was a subcutaneous abscess. Two biopsies showed a mixed lichenoid and granulomatous dermatitis. In one of them, the granulomatous reaction was focal and small. One biopsy lacked a granulomatous tissue reaction altogether; it showed an interface dermatitis, a perivascular and periadnexal lymphocytic infiltrate, and necrotizing lymphocytic small vessel vasculitis. A subsequent biopsy from the same patient additionally showed a focal granulomatous reaction. Our observation that infections by M. haemophilum can present with nongranulomatous or pauci-granulomatous reactions without necrosis is of note. Failure to suspect mycobacterial infection in such reactions contributes to probable underreporting of M. haemophilum and to misdiagnoses. Furthermore, our findings emphasize the importance of simultaneous biopsies for culture and histology in immunocompromised patients.

We present a case of a pulmonary nodular lesion in an immunocompetent patient documented at open lung biopsy to be due to Mycobacterium haemophilum. This organism has recently been recognized as a cause of disease in immunocompromised patients, presenting predominantly as skin lesions, arthritis, and rarely pneumonia. Because this mycobacterium is fastidious and difficult to grow without the use of special media and conditions, our case raises the possibility that M. haemophilum could be an underrecognized cause of granulomatous pulmonary lesions and should be considered particularly in cases where smears for acid-fast bacteria are positive but cultures are negative.

Mycobacterium tuberculosis was isolated from the eyelid, skin, tongue, and lungs of a green-winged macaw (Ara chloroptera). Two persons living in the same household were culture positive for pulmonary tuberculosis 3 to 4 years before tuberculosis was diagnosed in the bird. Although humans have not been shown to acquire tuberculosis from birds, an infected bird may be a sentinel for human infection.

Reports of the association of Mycobacterium haemophilum with disease in humans have greatly increased. At least 64 cases have now been reported, with symptoms ranging from focal lesions to widespread, systemic disease. The organism is now known to cause primarily cutaneous and subcutaneous infection, septic arthritis, osteomyelitis, and pneumonitis in patients who are immunologically compromised and lymphadenitis in apparently immunocompetent children. Underlying conditions in the compromised patients have included AIDS; renal, bone marrow, and cardiac transplantation; lymphoma; rheumatoid arthritis; marrow hypoplasia; and Crohn's disease. Reports have originated from diverse geographic areas worldwide. The epidemiology of M. haemophilum remains poorly defined; there appears to be a genetic diversity between strains isolated from different regions. The organism is probably present in the environment, but recovery by sampling has not been successful. M. haemophilum has several unique traits, including predilection for lower temperatures (30 to 32 degrees C) and requirement for iron supplementation (ferric ammonium citrate or hemin). These may in the past have compromised recovery in the laboratory. Therapy has not been well elucidated, and the outcome appears to be influenced by the patient's underlying immunosuppression. The organisms are most susceptible to ciprofloxacin, clarithromycin, rifabutin, and rifampin. Timely diagnosis and therapy require communication between clinician and the laboratory.

Mycobacterium genavense, a recently reported cause of a wasting illness in patients with AIDS, was isolated from a cervical lymph mode from a dog with severe hind limb weakness and from trachael tissue from a parrot with acute onset respiratory distress. Physicians caring for immunocompromised patients should consider birds and dogs potential sources of M. genavense infection and submit appropriate specimens for culture.

The purpose of this study was to describe the clinical presentation, treatment, and outcome of Mycobacterium haemophilum infection in patients undergoing bone marrow transplantation at a cancer center. Bone marrow transplant recipients with M haemophilum infection were identified upon culture of the organism by implementing the organism's unique requirements for growth. This report of the patients' clinical and immunologic course is based on a retrospective chart review. Two distinctly different presentations of M haemophilum infection were observed. Three patients presented with cutaneous lesions, typical of those seen in previous reports of the infection. Two others developed pulmonary disease only. All patients received directed therapy against M haemophilum, but respiratory failure developed in the patients with pneumonia and they died. The remaining 3 patients survived and are free of infection. These are the only reported cases of M haemophilum infection in bone marrow transplant recipients. Early diagnosis obtained through biopsy and special request for culture conditions conducive to the growth of the organism may decrease morbidity and mortality, particularly in patients with pulmonary disease.

Objectives: To identify the rate of surgical site infection and risk factors for surgical site infection in patients with cancer and to evaluate antibiotic use patterns on surgical oncology services., Design: Criterion standard., Setting: Memorial Sloan-Kettering Cancer Center, a comprehensive cancer center at a university hospital., Patients: Over a 15-month period, 1226 patients undergoing 1283 surgical procedures performed by the Breast, Colorectal, and Gastric-Mixed Tumor surgical services., Main Outcome Measure: Direct observation of surgical sites was performed by a single, surgeon-trained member of the hospital's Infection Control Section, adhering to an established protocol for grading of the surgical site., Results: Operative procedures accounted for the following traditional wound class distributions: class I (clean), 630 cases; class II (clean-contaminated), 577 cases; class III (contaminated), 29 cases; and class IV (dirty-infected), 47 cases. Surgical site infection rates were 3.8% in class I; 8.8% in class II; 20.7% in class III; and 46.9% in class IV procedures. The mean (+/- SD) age was 57.7 +/- 14.3 years and the Anesthesiology Society of America physical assessment score, 2.3 +/- 0.7. The mean (+/- SD) operation time was 145 +/- 104.9 minutes. Logistic regression analysis demonstrated several risk factors for surgical site infection: obesity (P < .0001); a contaminated or dirty-infected surgical procedure category (P < .0001); operation time greater than 4 hours (P = .0004); Anesthesiology Society of America physical assessment score of 3 or greater (P < .01); and preoperative length of stay of 3 or more days (P = .03)., Conclusions: Risk factors for surgical site infection in patients with cancer are similar to those found in the National Nosocomial Infections Surveillance System. However, as an individual risk factor among our patient population, obesity contributed as strongly as the surgical procedure category to a patient's likelihood of acquiring a surgical site infection. In addition to Anesthesiology Society of America status, length of the surgical procedure, and surgical procedure category, obesity should warrant consideration as an individual risk factor for surgical site infection.

A resurgence of tuberculosis has occurred in recent years in the United States and abroad. Deteriorating public health services, increasing numbers of immigrants from countries of endemicity, and coinfection with the human immunodeficiency virus (HIV) have contributed to the rise in the number of cases diagnosed in the United States. Outbreaks of resistant tuberculosis, which responds poorly to therapy, have occurred in hospitals and other settings, affecting patients and health care workers. This review covers the pathogenesis, epidemiology, clinical presentation, laboratory diagnosis, and treatment of Mycobacterium tuberculosis infection and disease. In addition, public health and hospital infection control strategies are detailed. Newer approaches to epidemiologic investigation, including use of restriction fragment length polymorphism analysis, are discussed. Detailed consideration of the interaction between HIV infection and tuberculosis is given. We also review the latest techniques in laboratory evaluation, including the radiometric culture system, DNA probes, and PCR. Current recommendations for therapy of tuberculosis, including multidrug-resistant tuberculosis, are given. Finally, the special problem of prophylaxis of persons exposed to multidrug-resistant tuberculosis is considered.

Mycobacterium haemophilum is emerging as a pathogen of immunocompromised patients particularly those with AIDS and organ transplants. Infection has also occurred in healthy children. Adults usually present with cutaneous manifestations, septic arthritis or occasionally pneumonia. Children have perihilar, cervical or submandibular adenitis. The organism grows on mycobacterial media supplemented with ferric ammonium citrate or hemin, incubated at 30 degrees C to 32 degrees C, two to three weeks after inoculation. The most active antimicrobial agents in vitro are amikacin, ciprofloxacin, clarithromycin, rifabutin and rifampin. Development of resistance to the rifamycins has been demonstrated after patients were treated for several months with several antimycobacterial agents, including the rifamycins. Treatment for several months with at least two agents demonstrated to have low MICs for the organism has been shown to be effective.

Mycobacterium haemophilum is an emerging opportunistic pathogen, and since 1989, infections caused by this organism have been identified more frequently in the New York City area than in any other region of the United States. A DNA fingerprinting method, based on restriction fragment length polymorphisms (RFLPs) was developed. A genomic library of M. haemophilum isolate 1A was constructed; screening the library yielded a recombinant strain that incorporated a genetic element present in multiple copies in the M. haemophilum genome. This clone was used to produce a probe for RFLP analyses of PvuII digests of genomic DNA. We used this probe to determine the RFLP patterns of 43 clinical isolates of M. haemophilum from 28 patients. A total of six distinct patterns were observed. Two patterns, designated types 1 and 2, accounted for 91% of the infections in patients from the New York City area. Two isolates from Arizona had identical patterns but were distinct from those of New York isolates, and an isolate from Israel, the type strain, had another distinct pattern (type 6). The type 6 pattern was also seen in a recent isolate from Norway. All of the type 1 isolates and 60% of the type 2 isolates were recovered from patients with AIDS in the New York City area. This molecular subtyping method should provide a useful tool for epidemiological studies and may help identify the associated risk factors, vehicles, and possible reservoirs of this newly emerging pathogen.

Previous reports of F. oryzihabitans sepsis involving central venous access devices reveal a relatively high rate of complications, including device removal, despite a course of broad-spectrum anti-microbials with compatible in vitro susceptibility results. In the present report of 22 cases of F. oryzihabitans sepsis treated at Memorial Sloan-Kettering Cancer Center from February 1986 through September 1993, the majority of CVAD-related infections with F. oryzihabitans were successfully treated with a 14-day course of antimicrobials with antipseudomonal activity, and removal of the device was usually not required. Factors that may complicate successful treatment of CVAD-related sepsis caused by F. oryzihabitans include polymicrobial infections and premature discontinuation of antibiotic therapy.

Objective: To describe 13 infections caused by Mycobacterium haemophilum., Design: Identification of patients by microbiologic record review, followed by medical record review and a case-control study., Setting: Seven metropolitan hospitals in New York., Patients: All patients with M. haemophilum infections diagnosed between January 1989 and September 1991 and followed through September 1992. Surviving patients were enrolled in the case-control study., Results: Infection with M. haemophilum causes disseminated cutaneous lesions, bacteremia, and diseases of the bones, joints, lymphatics, and the lungs. Improper culture techniques may delay laboratory diagnosis, and isolates may be identified incorrectly as other mycobacterial species. Persons with profound deficits in cell-mediated immunity have an increased risk for infection. These include persons with human immunodeficiency virus infection or lymphoma and those receiving medication to treat immunosuppression after organ transplant. Various antimycobacterial regimens have been used with apparent success to treat M. haemophilum infection. However, standards for defining antimicrobial susceptibility to the organism do not exist., Conclusions: Clinicians should consider this pathogen when evaluating an immunocompromised patient with cutaneous ulcerating lesions, joint effusions, or osteomyelitis. Microbiologists must be familiar with the fastidious growth requirements of this organism and screen appropriate specimens for mycobacteria using an acid-fast stain. If acid-fast bacilli are seen, M. haemophilum should be considered as the infecting organism as well as other mycobacteria, and appropriate media and incubation conditions should be used.

Objective: To evaluate infectious morbidity associated with long-term use of venous access devices., Design: Prospective, observational study., Setting: Comprehensive cancer center at a university hospital., Participants: 1431 consecutive patients with cancer requiring 1630 venous access devices for long-term use inserted between 1 June 1987 and 31 May 1989., Measurements: Quantitative microbiologic tests to identify device-related bacteremia and fungemia, catheter tunnel infection, pocket infection in implantable port devices, and site infections; number of days the device remained in situ and time until infectious morbidity; vessel or device thrombosis and device breakage., Results: At least one device-related infection occurred with 341 of 788 (43% [95% CI, 39% to 47%]) catheters compared with 57 of 680 (8% [CI, 6% to 10%]) completely implanted ports (P < or = 0.001). Device-related bacteremia or fungemia is the predominant infection occurring with catheters, whereas ports have a more equal distribution of pocket, site, and device-related bacteremia. The predominant organisms isolated in catheter-related bacteremia were gram-negative bacilli (55%) compared with gram-positive cocci (65.5%) in port-related bacteremia. The number of infections per 1000 device days was 2.77 (95% CI, 2.48 to 3.06) for catheters compared with 0.21 (CI, 0.16 to 0.27) for ports (P < or = 0.001). Based on a parametric model of time to first infection, devices lasted longer in patients with solid tumors than in those with hematopoietic tumors. Ports lasted longer than catheters across all patient groups., Conclusions: The incidence of infections per device-day was 12 times greater with catheters than with ports. Patients with solid tumors were the least likely to have device-related infectious morbidity compared with those with hematologic cancers. The reasons for the difference in infectious complications is uncertain but may be attributable to type of disease, intensity of therapy, frequency with which devices are accessed, or duration of neutropenia.

The diagnostic mycobacterial laboratory of the 1990s must respond to a change in the clinical spectrum of mycobacterial infections brought about by an increase in the number of patients who are immunocompromised, are indigent, or have temporary or permanent implanted devices. Emerging pathogens such as Mycobacterium haemophilum and Mycobacterium genavense, multidrug-resistant strains of Mycobacterium tuberculosis, and catheter infections with rapidly growing mycobacteria are examples of new issues. Fortunately, new methods for detection and identification of microbes have been or are being developed. Procedures that, when applied directly to clinical specimens or actively growing cultures, dramatically reduce the time to diagnosis of mycobacterial infections include radiometric broth, lysis-centrifugation, and biphasic systems for specimen culture, and DNA probes, high-performance liquid chromatography, DNA hybridization, restriction fragment length polymorphism, and gene amplification for organism detection and identification. At present, in vitro antimicrobial susceptibility tests are most helpful in guiding treatment of infections caused by M. tuberculosis and rapidly growing mycobacteria.

Mycobacterium haemophilum, first described in 1978, can cause severe infections of skin, respiratory tract, bone, and other organs of immunocompromised patients. There is no standardized antimicrobial susceptibility test, and for the 27 reported cases, a variety of test methods have been used. This paper reports the in vitro test results for 17 isolates of M. haemophilum recovered from 12 patients in the New York City area. MICs of 16 antimicrobial agents were determined in microtiter trays containing Middlebrook 7H9 broth plus 60 microM hemin, inoculated with 10(6) CFU of the organism per ml and incubated at 30 degrees C for 10 days. Ethambutol, ethionamide, tetracycline, cefoxitin, and trimethoprim-sulfamethoxazole were inactive against initial isolates from the 12 patients. Isoniazid was weakly active with a MIC for 50% of strains tested (MIC50) of 8 micrograms/ml and a MIC90 of > 32 micrograms/ml. Three quinolones, ciprofloxacin, ofloxacin, and sparfloxacin, were moderately active with MIC50s of 2 to 4 micrograms/ml and MIC90s of 4 to 8 micrograms/ml. Amikacin and clofazamine were active with MIC90s of 4 and 2 micrograms/ml, respectively. Clarithromycin was the most active macrolide with a MIC90 of < or = 0.25 microgram/ml. The MIC90 of azithromycin was 8 micrograms/ml, and the MIC90 of erythromycin was 4 micrograms/ml. The rifamycins were active with a MIC90 of 1 microgram/ml for rifampin and one of < or = 0.03 micrograms/ml for rifabutin. For a second isolate from the skin of one patient and a isolate from an autopsy culture of the spleen of a second patient, MICs of rifampin and rifabutin were > 16 microgram/ml, whereas initial isolates were inactivated by low concentrations of the rifamycins. Both patients had been treated for several months with several antimicrobial agents, including a rifamycin.

Purpose, Patients, and Methods: Malassezia furfur has usually been described as a cause of catheter-related sepsis in neonates receiving intravenous lipid emulsion. We report seven cases of catheter-related M. furfur fungemia that occurred in seven immunocompromised patients including four adults and three children who were not neonates. Only two of these patients were receiving concurrent intravenous lipid emulsion., Results: All positive blood cultures were obtained from a central venous access device, one of which was a port device. Quantitative M. furfur colony counts ranged from 50 cfu/mL to greater than 1,000 cfu/mL. All seven patients were treated with amphotericin B. Blood drawn through the central lines of three patients yielded additional organisms. One central venous access device required removal due to persistently positive M. furfur blood cultures despite treatment with amphotericin B., Conclusion: We conclude that catheter-related M. furfur fungemia occurs in immunocompromised patients with central venous access devices whether or not they are receiving intravenous lipids. Prompt, aggressive treatment with amphotericin B (1 mg/kg/d) may spare patients removal of their central venous access device. Further studies are needed to determine the role of endogenous lipids in the development of catheter-related M. furfur fungemia and to determine if there is a seasonal incidence in populations other than neonates, since all of our cases occurred between late March and July.

Four cases of infection with Mycobacterium haemophilum occurred at a single hospital in a seven-month period. Only 22 cases have been reported since 1976. All four patients were immunocompromised; two had AIDS and two were the first known recipients of allogeneic bone marrow transplants (BMT) to develop the infection. One BMT recipient died of Mycobacterium haemophilum pneumonia. The organism requires hemin or ferric ammonium citrate and incubation of media at 30 degrees C for optimum growth. Clinicians and microbiologists should consider infection with Mycobacterium haemophilum, particularly when specimens are from immunocompromised patients with unexplained illness and/or when acid-fast bacilli are seen on smear.

An unusual case of disseminated Nocardia brasiliensis infection is presented. The patient, who had been receiving chronic dexamethasone therapy for 4 years, had pneumonia and septic arthritis of the left knee due to N. brasiliensis. To our knowledge, this is the first report from the United States of a synovial joint infection with this organism. Disseminated disease due to N. brasiliensis is infrequently reported; it is most often seen in the immunocompromised patient and is often unresponsive to therapy.

With increased use of surgically implanted silastic central venous catheters, there has been an increase in the recovery from blood cultures at Memorial Sloan-Kettering Cancer Center (New York) of environmental and skin organisms including the red yeast Rhodotorula. From 1985 through 1989, 23 patients had catheter-related Rhodotorula sepsis. All 23 patients had indwelling central venous catheters that had been in place from 1 to 22 months (average, 9.3 months) prior to the detection of fungemia. All patients had blood drawn both through the catheter and from a peripheral source, and only one patient had a peripheral blood culture positive for Rhodotorula. Colony counts of yeast from the catheter cultures often exceeded 100 (15 patients) and even 1,000 (seven patients) cfu/mL of blood. Thirteen of the patients were treated with antifungal therapy and had the catheter removed, and five patients received antifungal therapy without catheter removal (suggesting that compulsory removal of the catheter may not always be required). Five patients had the catheter removed without antifungal therapy. All patients survived the fungemic episode and experienced no recurrence of the infection.

Four cases of meningitis due to beta-hemolytic non-A, non-D streptococci among adult patients with neoplastic disease are reported. All four patients had head or neck tumors for greater than or equal to 4 years, and all had undergone surgery for these tumors. Three of four patients had received local radiation therapy. None of the patients were neutropenic. One patient died. A review of the literature revealed that most patients with non-A, non-D streptococcal meningitis had disruption of the normal barrier protecting the CNS due to trauma, surgery, or the presence of a tumor, or had extensive exposure to animals or an underlying medical disease. Infection with non-A, non-D streptococci should be considered in any patient with meningitis who has a tumor of the head or neck and who has undergone surgery and/or radiation therapy.

A significant increase in the use of vascular access devices has changed the spectrum of organisms causing bacteremia and fungemia at Memorial Sloan-Kettering Cancer Center. This paper documents the 1988 laboratory experience with bacteremia and fungemia and contrasts some of that data with information obtained in 1984. In 1988, 439 tunnelled-catheters and 355 ports were inserted in patients; 2,778 organisms were subsequently recovered from 933 episodes of bacteremia and fungemia. Fifty-percent of the episodes of bacteremia and fungemia were vascular access device-related. Compared to 1984, the relative incidence of bacteremia due to gram-positive organisms increased from 33 to 43%, polymicrobic cultures increased from 24 to 27%, and the number of organisms with colony counts greater than 100 cfu/ml increased from 24 to 44%. In 1988, device-related sepsis was often caused by Acinetobacter spp., Bacillus spp., Corynebacterium spp., pseudomonads other than Pseudomonas aeruginosa, and coagulase-negative staphylococci. Infection was also caused by species of flavobacteria, Micrococcus, and Rhodotorula. Efforts required for identification of many of the newer pathogens have escalated material and personnel costs.

Seven Pseudomonas aeruginosa strains found to be susceptible to gentamicin by the Autobac I system and resistant by the Bauer-Kirby disk diffusion method were tested for the presence of mixed populations of cells. Double zones of inhibition randomly appeared on gentamicin disk diffusion plates, and susceptible and resistant subpopulations were isolated from these plates. Growth kinetic studies of separated strains and mixed subpopulations indicated that the susceptible organisms grew rapidly and were read as susceptible at 5 h with the Autobac I system. Resistant organisms entered a sustained lag phase and did not achieve sufficient turbidity to be read as resistant with the Autobac I system before 6 h. Thus, a false reading of susceptible could be obtained with the Autobac I system, depending on the ratio of susceptible organisms to resistant organisms selected for testing. A mixed susceptible and resistant population could be recognized by extending the incubation time of the Autobac I cuvette or by using other susceptibility methods to test isolates with light-scattering indexes of less than 1.0.

Over 18,000 clinical specimens collected in Vacutainer tubes with sodium polyanethol sulfonate were inoculated into modified Columbia broth (MCB) with and without 10% sucrose. The effects of venting and shaking on recovery were studied. The volume of the blood had a definite effect on the recovery rate. When inoculum size was held constant, recovery of aerobic and facultative organisms was maximal in vented and shaken bottles; the presence of sucrose had no demonstrable effect, recovery of anaerobes was maximal using an unvented bottle incubated under stationary conditions; a significantly greater recovery of facultatives and a marginally greater recovery of anaerobes was obtained with the hypertonic formulation. We conclude that a hypertonic formulation of MCB offers no advantage in the recovery of anaerobes but is of value in the recovery of facultatives and anaerobes. It is recommended that blood cultures be routinely inoculated into isotonic MCB and then vented and shaken for at least 4 hours, and hypertonic MCB incubated without venting or shaking.

Disseminated mycobacterial infections are commonly seen in acquired immunodeficiency syndrome (AIDS) patients, and laboratory culture is the best method for diagnosing these infections. In addition to conventional agar media, we used BACTEC 12A (Johnston Laboratories, Inc., Towson, Md.) broth medium for culture. More isolates of Mycobacterium avium complex and Mycobacterium tuberculosis were recovered from 12A broth than from Lowenstein-Jensen or Middlebrook 7H11 agar. Also, the average detection time of these mycobacteria was the earliest with 12A broth. Stool examination has been helpful in diagnosing mycobacterial disease in AIDS patients, and in this study both acid-fast stain and culture of fecal material was necessary for efficient detection of mycobacteria. Another sensitive and practical method for detecting mycobacterial infections in patients with AIDS is the Isolator lysis-centrifugation system (Du Pont Co., Wilmington, Del.) which offers the advantage of quantitating the degree of mycobacteremia. Laboratories should be alerted to the possibility of mixed mycobacterial infection in patients with AIDS, and positive cultures should be repeatedly examined to detect coinfection with a slower-growing mycobacterium such as M. tuberculosis as well as M. avium complex.

A case of liver infection caused by Coniothyrium fuckelii is described in a patient with acute myelogenous leukemia. This fungus is found in the soil and can be a pathogen of plants. Coniothyrium spp. are members of the order Sphaeropsidales, an order composed of fungi whose conidiomata are usually pycnidia with the conidiogenous hymenium lining the walls of the locule. Coniothyrium spp. must be differentiated from Phoma spp. and Hendersonula spp., the two most commonly isolated members of the Sphaeropsidales.

In the immunosuppressed patient the usual hallmarks of infection, such as leukocytosis and antibody response, may be absent; thus the microbiology laboratory plays a fundamental role in the diagnosis of infection. Methods used to demonstrate microorganisms in a specimen submitted to the laboratory include visualization techniques, culture, and non-cultural methods involving immunologic, immunochemical, and nucleic acid probe methodologies. Because infections in the immunosuppressed patient may be caused by unusual organisms whose identification requires special techniques, close communication between the physician and the laboratory is important. New technologies allow the clinical microbiology laboratory to gather important diagnostic information more readily. When these results are delivered rapidly to physicians via computerized information systems, care of the immunosuppressed patient is significantly enhanced.