Mycobacterium chelonei iatrogenic infections

Revisiting John Snow to Meet the Challenge of Nontuberculous Mycobacterial Lung Disease

Nontuberculous mycobacteria (NTM) are ubiquitous components of the soil and surface water microbiome. Disparities by sex, age, and geography demonstrate that both host and environmental factors are key determinants of NTM disease in populations, which predominates in the form of chronic pulmonary disease. As the incidence of NTM pulmonary disease rises across the United States, it becomes increasingly evident that addressing this emerging human health issue requires a bold, multi-disciplinary research framework that incorporates host risk factors for NTM pulmonary disease alongside the determinants of NTM residence in the environment. Such a framework should include the assessment of environmental characteristics promoting NTM growth in soil and surface water, detailed evaluations of water distribution systems, direct sampling of water sources for NTM contamination and species diversity, and studies of host and bacterial factors involved in NTM pathogenesis. This comprehensive approach can identify intervention points to interrupt the transmission of pathogenic NTM species from the environment to the susceptible host and to reduce NTM pulmonary disease incidence.

Medical Tourism and Postoperative Infections: A Systematic Literature Review of Causative Organisms and Empiric Treatment

BACKGROUND

Medical tourism has become increasingly globalized as individuals travel abroad to receive medical care. Cosmetic patients in particular are more likely to seek surgery abroad to defray costs. Unfortunately, not all procedures performed abroad adhere to strict hygienic regulations, and bacterial flora vary. As a result, it is not uncommon for consumers to return home with difficult-to-treat postoperative infections.

METHODS

A systematic literature review of PubMed, Ovid, Web of Science, and Cumulative Index to Nursing and Allied Health Literature databases was performed to assess the microbiology patterns and medical management of patients with postoperative infections after undergoing elective surgery abroad.

RESULTS

Forty-two cases of postoperative infections were reported among patients who underwent elective surgery abroad. Most cases were reported from the Dominican Republic, and the most common elective procedures were abdominoplasty, mastopexy, and liposuction. Rapidly growing mycobacteria such as Mycobacterium abscessus, Mycobacterium fortuitum, and Mycobacterium chelonae were among the most common causes of postoperative infection, with M. abscessus involving 74 percent of cases. Most cases were treated with surgical débridement and a combination of antibiotics. Clarithromycin, amikacin, and moxifloxacin were the most common drugs used for long-term treatment.

CONCLUSIONS

When encountering a patient with a history of medical tourism and treatment-refractory infection, rapidly growing mycobacteria must be considered. To increase the likelihood of yielding a diagnostic organism, multiple acid-fast bacilli cultures from fluid and débridement content should be performed. There has been reported success in treating rapidly growing mycobacterial infections with a combination of antibiotics including clarithromycin, amikacin, and moxifloxacin.

Outbreak of Rapidly Growing Nontuberculous Mycobacteria Among Patients Undergoing Cosmetic Surgery in the Dominican Republic

Rapidly growing nontuberculous mycobacteria (RG-NTM), which can contaminate inadequately sterilized medical instruments, have been known to cause serious postsurgical skin and soft tissue infections that often are characterized by a prolonged incubation period and a disfiguring clinical course. Historically, these infections have been associated with surgical procedures performed outside the United States. The Centers for Disease Control and Prevention recently reported an outbreak of RG-NTM infections among women who underwent cosmetic surgery in the Dominican Republic. Because of the large Dominican American community in upper Manhattan, we have recently observed a number of these cases at NewYork-Presbyterian Hospital/Columbia University Medical Center. We highlight the case of a 55-year-old woman who developed a postsurgical RG-NTM infection after bilateral breast reduction in the Dominican Republic; she experienced progressive deformity of her left breast until the causative pathogen was identified 20 months after her initial surgery. To assist in the timely diagnosis and treatment of these infections, we aim to promote greater awareness among physicians who are likely to encounter such patients. We present the pathologic findings of a review of 7 cases of RG-NTM infections seen at NewYork-Presbyterian Hospital/Columbia University Medical Center and discuss the diagnostic and therapeutic challenges associated with these infections, such as prolonged incubation periods, the need for acid-fast stains and mycobacterial cultures, and the combination of surgical therapy and lengthy antibiotic courses that are often required for treatment.

A Cluster ofMycobacterium wolinskyiSurgical Site Infections at an Academic Medical Center

Objective

To study a cluster ofMycobacterium wolinskyisurgical site infections (SSIs).

Design

Observational and case-control study.

Setting

Academic hospital.

Patients.

Subjects who developed SSIs withM. wolinskyifollowing cardiothoracic surgery.

Methods

Electronic surveillance was performed for case finding as well as electronic medical record review of infected cases. Surgical procedures were observed. Medical chart review was conducted to identify risk factors. A case-control study was performed to identify risk factors for infection; Fisher exact or Kruskal-Wallis tests were used for comparisons of proportions and medians, respectively. Patient isolates were studied using pulsed-field gel electrophoresis (PFGE). Environmental microbiologic sampling was performed in operating rooms, including high-volume water sampling.

Results

Six definite cases ofM. wolinskyiSSI following cardiothoracic surgery were identified during the outbreak period (October 1, 2008–September 30, 2011). Having cardiac surgery in operating room A was significantly associated with infection (odds ratio, 40;P= .0027). Observational investigation revealed a cold-air blaster exclusive to operating room A as well a microbially contaminated, self-contained water source used in heart-lung machines. The isolates were indistinguishable or closely related by PFGE. No environmental samples were positive forM. wolinskyi.

Conclusions

No single point source was established, but 2 potential sources, including a cold-air blaster and a microbially contaminated, self-contained water system used in heart-lung machines for cardiothoracic operations, were identified. Both of these potential sources were removed, and subsequent active surveillance did not reveal any further cases ofM. wolinskyiSSI.

Infect Control Hosp Epidemiol2014;35(9):1169-1175

Postsurgical wound infections due to rapidly growing mycobacteria in Swiss medical tourists following cosmetic surgery in Latin America between 2012 and 2014

Between October 2012 and August 2014, several Swiss patients developed severe soft tissue infections due to rapidly growing mycobacteria following cosmetic surgery in the Dominican Republic, Ecuador and Mexico. Infections were caused by Mycobacterium abscessus (n=5), Mycobacterium sp. JAN1 (n=1) and M. conceptionense (n=1). Similar cases may have remained unrecognised due to a lack of notification requirements. Microbiological work-up of medical tourists with infections following cosmetic surgery should include rapidly growing mycobacteria.

Mycobacterium monacense: a mycobacterial pathogen that causes infection of the hand

We present a report of a diabetic patient with an infection of his left thumb and thenar eminence. Standard cultures of drainage and tissue biopsy were unrevealing. The infection progressed despite empiric antibacterial agent therapy and multiple debridements. Two intraoperative tissue biopsies revealed a yellow-pigmented, rapidly growing Mycobacterial nontuberculous species. The organism was identified as Mycobacterium monacense, a newly described species. The patient was cured with a 6-week course of clarithromycin and levofloxacin.

Fish gambler's tenosynovitis caused by Mycobacterium marinum: environmental investigation of a fishing pond in Southern Taiwan

We describe a patient with Mycobacterium marinum tenosynovitis associated with a fish spine injury acquired at a gambling fishing pond in southern Taiwan and identify the source of the infection. M. marinum was isolated from fishing ponds and underground water and wastewater at the site. The isolates shared the same pulsed-field gel electrophoresis pattern as the patient. M. marinum was not detected in 54 samples obtained from 27 fish. Mycobacterium gordonae was isolated from 24 samples collected from the fish. Mycobacterium abscessus was isolated from 3 fish samples (Lateolabrax japonicus 1 and Sciaenops ocellatus 2). M. abscessus and M. gordonae were isolated from all water samples. This investigation provides strong evidence that the predisposing factor for the M. marinum infection was with a fish spine injury acquired at a gambling fishing pond. The source of the infection was the contaminated pond water.

Nontuberculous Mycobacterial Breast Implant Infections

BACKGROUND

For reasons that are unclear, the incidence of nontuberculous mycobacterial disease is increasing worldwide. Periprosthetic nontuberculous mycobacterial infections following augmentation mammaplasty and breast reconstruction have been reported previously in the form of case reports.

METHODS

This retrospective case series examines periprosthetic nontuberculous mycobacterial infections in two western Canadian cities (Edmonton, Alberta, and Vancouver, British Columbia) over a 10-year time period.

RESULTS

Ten patients were identified, four of whom had bilateral infections. The most common isolate was Mycobacterium fortuitum. Clinical features were similar to nonmycobacterial periprosthetic infections. The median time to onset of symptoms was 4.5 weeks and the median time to culture an organism was 5.4 weeks. The median duration of antibiotic therapy was 22 weeks. Patients required a mean of three additional operations after diagnosis. Nine patients underwent explantation of the involved implant(s). Reimplantation was performed in six patients a median of 11.5 months after explantation. All cases of reimplantation were successful.

CONCLUSIONS

Experience with this postoperative complication is limited, as nontuberculous mycobacteria represent a minority of the pathogens responsible for periprosthetic infections. In the absence of specific features with which to identify patients at risk, the surgeon must be aware of the possibility of this infection. To achieve earlier diagnosis, the clinician should have a high index of suspicion in a patient with delayed onset of symptoms, negative preliminary cultures, and a periprosthetic infection that fails to resolve following a course of conventional antimicrobial treatment. With appropriate treatment, nontuberculous mycobacterial periprosthetic infections can be managed successfully.

Mycobacteria in drinking water distribution systems: ecology and significance for human health

In contrast to the notorious pathogens Mycobacterium tuberculosis and M. leprae, the majority of the mycobacterial species described to date are generally not considered as obligate human pathogens. The natural reservoirs of these non-primary pathogenic mycobacteria include aquatic and terrestrial environments. Under certain circumstances, e.g., skin lesions, pulmonary or immune dysfunctions and chronic diseases, these environmental mycobacteria (EM) may cause disease. EM such as M. avium, M. kansasii, and M. xenopi have frequently been isolated from drinking water and hospital water distribution systems. Biofilm formation, amoeba-associated lifestyle, and resistance to chlorine have been recognized as important factors that contribute to the survival, colonization and persistence of EM in water distribution systems. Although the presence of EM in tap water has been linked to nosocomial infections and pseudo-infections, it remains unclear if these EM provide a health risk for immunocompromised people, in particular AIDS patients. In this regard, control strategies based on maintenance of an effective disinfectant residual and low concentration of nutrients have been proposed to keep EM numbers to a minimum in water distribution systems.

Unusual infectious complications of dermatologic procedures

Because dermatologic procedures disrupt skin integrity, they alter the body's protective barrier and predispose individuals to cutaneous infection. Postoperative wound infections--even with common pathogens such as S. aureus--seldom complicate dermatologic procedures; however, unusual infections have been reported to complicate excisions, biopsies, skin grafts, chemical peels, dermabrasion, laser resurfacing, liposuction, blepharoplasty, and injections (eg, with anesthetic solutions or botulinum toxin). Numerous environmental and patient risk factors increase the rate of postoperative wound infections, but otherwise healthy individuals undergoing relatively simple procedures are sometimes affected. Obtaining a thorough patient, history (including history of prior HSV infection or any immunocompromising factors) is crucial. Patients should be warned of potential complications, particularly when they are undergoing cosmetic procedures. It is important to maintain a high index of suspicion for possible wound infection in all patients that extends several months postoperatively. Manifestations of unusual postoperative infections are highly variable, and they might be secondary to bacterial, fungal, viral, or parasitic pathogens. Bacterial lesions are often polymicrobial, and bacterial superinfection can exacerbate other wound complications such as HSV reactivation. Most wound infections remain localized, but occasionally systemic disease occurs. For example, cutaneous diphtheria or rapidly growing mycobacteria rarely disseminate, whereas TSS results in systemic disease caused by toxin release. Some unusual postsurgical infections are self-limited, but they can still be potentially life threatening or disfiguring. Antimicrobial prophylaxis might reduce the risk of wound infection in some cases. Clinicians can better care for patients by becoming familiar with the causes and clinical manifestations of unusual dermatologic postoperative wound infections (Table 1). Following the recognition of an infectious process, appropriate diagnostic procedures allow for pathogen identification and the prompt institution of indicated therapy.

The genetics of nontuberculous mycobacterial infection

The molecular aetiology of familial susceptibility to disseminated mycobacterial disease, usually involving weakly pathogenic strains of mycobacteria, has now been elucidated in more than 30 families. Mutations have been identified in five genes in the interleukin-12-dependent interferon-gamma pathway, highlighting the importance of this pathway in human mycobacterial immunity. Knowledge derived from the study of these rare patients contributes to our understanding of the immune response to common mycobacterial pathogens such as Mycobacterium tuberculosis and Mycobacterium leprae, which remain major public health problems globally. This knowledge can be applied to the rational development of novel therapies and vaccines for these important mycobacterial diseases.

Clinical and taxonomic status of pathogenic nonpigmented or late-pigmenting rapidly growing mycobacteria

The history, taxonomy, geographic distribution, clinical disease, and therapy of the pathogenic nonpigmented or late-pigmenting rapidly growing mycobacteria (RGM) are reviewed. Community-acquired disease and health care-associated disease are highlighted for each species. The latter grouping includes health care-associated outbreaks and pseudo-outbreaks as well as sporadic disease cases. Treatment recommendations for each species and type of disease are also described. Special emphasis is on the Mycobacterium fortuitum group, including M. fortuitum, M. peregrinum, and the unnamed third biovariant complex with its recent taxonomic changes and newly recognized species (including M. septicum, M. mageritense, and proposed species M. houstonense and M. bonickei). The clinical and taxonomic status of M. chelonae, M. abscessus, and M. mucogenicum is also detailed, along with that of the closely related new species, M. immunogenum. Additionally, newly recognized species, M. wolinskyi and M. goodii, as well as M. smegmatis sensu stricto, are included in a discussion of the M. smegmatis group. Laboratory diagnosis of RGM using phenotypic methods such as biochemical testing and high-performance liquid chromatography and molecular methods of diagnosis are also discussed. The latter includes PCR-restriction fragment length polymorphism analysis, hybridization, ribotyping, and sequence analysis. Susceptibility testing and antibiotic susceptibility patterns of the RGM are also annotated, along with the current recommendations from the National Committee for Clinical Laboratory Standards (NCCLS) for mycobacterial susceptibility testing.

Clinical and taxonomic status of pathogenic nonpigmented or late-pigmenting rapidly growing mycobacteria

The history, taxonomy, geographic distribution, clinical disease, and therapy of the pathogenic nonpigmented or late-pigmenting rapidly growing mycobacteria (RGM) are reviewed. Community-acquired disease and health care-associated disease are highlighted for each species. The latter grouping includes health care-associated outbreaks and pseudo-outbreaks as well as sporadic disease cases. Treatment recommendations for each species and type of disease are also described. Special emphasis is on the Mycobacterium fortuitum group, including M. fortuitum, M. peregrinum, and the unnamed third biovariant complex with its recent taxonomic changes and newly recognized species (including M. septicum, M. mageritense, and proposed species M. houstonense and M. bonickei). The clinical and taxonomic status of M. chelonae, M. abscessus, and M. mucogenicum is also detailed, along with that of the closely related new species, M. immunogenum. Additionally, newly recognized species, M. wolinskyi and M. goodii, as well as M. smegmatis sensu stricto, are included in a discussion of the M. smegmatis group. Laboratory diagnosis of RGM using phenotypic methods such as biochemical testing and high-performance liquid chromatography and molecular methods of diagnosis are also discussed. The latter includes PCR-restriction fragment length polymorphism analysis, hybridization, ribotyping, and sequence analysis. Susceptibility testing and antibiotic susceptibility patterns of the RGM are also annotated, along with the current recommendations from the National Committee for Clinical Laboratory Standards (NCCLS) for mycobacterial susceptibility testing.

Nosocomial outbreaks/pseudo-outbreaks caused by nontuberculous mycobacteria

Nosocomial outbreaks and pseudo-outbreaks caused by the nontuberculous mycobacteria (NTM) have been recognized for more than 20 years and continue to be a problem. Most of these outbreaks have involved the rapidly growing mycobacterial species Mycobacterium fortuitum and M. abscessus. The reservoir for these outbreaks is generally municipal and (often separate) hospital water supplies. These mycobacterial species and others are incredibly hardy, able to grow in municipal and distilled water, thrive at temperatures of 45 degrees C or above (M. xenopi and M. avium complex), and resist the activity of organomercurials, chlorine, 2% concentrations of formaldehyde and alkaline glutaraldehyde, and other commonly used disinfectants. Disease outbreaks usually involve sternal wound infections, plastic surgery wound infections, or postinjection abscesses. Pseudo-outbreaks most commonly relate to contaminated bronchoscopes and endoscopic cleaning machines (M. abscessus) and contaminated hospital water supplies (M. xenopi). Knowledge of the reservoir of these species, their great survival capabilities within the hospital, and newer molecular techniques for strain comparison have helped control and more quickly identify current nosocomial outbreaks or pseudo-outbreaks caused by the NTM.

Mycobacterial contamination of fibreoptic bronchoscopes

Because of the increasing numbers of immunosuppressed patients and the general resurgence of mycobacterial infection, diagnostic bronchoalveolar lavage (BAL) using a fibreoptic bronchoscope is an important and frequent procedure. A contaminated bronchoscope may introduce spurious mycobacteria into specimens causing diagnostic confusion, infect the patient with mycobacteria, or be a vehicle for cross-infection. Bronchoscopes are difficult to disinfect adequately if they are not properly cleaned (which may include stripping down channel valves) or are damaged. Bronchoscope washers have also contributed to the problem when glutaraldehyde becomes too dilute or they become heavily contaminated with environmental mycobacteria. Future solutions to prevent contamination include the regular maintenance of bronchoscopes and washers, having adequate cleaning and disinfection protocols and ensuring that they are adhered to, improving bronchoscope and washer design, and developing alternative disinfectants or new ways of using current ones. All these will probably have considerable cost implications for hospitals.

DNA large restriction fragment patterns of sporadic and epidemic nosocomial strains of Mycobacterium chelonae and Mycobacterium abscessus

Large restriction fragment (LRF) pattern analysis of genomic DNA using pulsed-field gel electrophoresis was performed on three reference strains, 32 sporadic isolates, and 92 nosocomial isolates from 12 epidemics of Mycobacterium chelonae and Mycobacterium abscessus. Only 17 of 30 (57%) unrelated strains of M. abscessus, compared with 10 of 11 (91%) of M. chelonae strains, gave satisfactory DNA extractions, with the remainder resulting in highly fragmented DNA. DraI, AsnI, XbaI, and SpeI gave satisfactory LRF patterns. Sporadic isolates of the two species had highly variable LRF patterns, except for one reference strain and one sporadic isolate of M. chelonae that differed by only two to five bands. Evaluation of repeat isolates from five patients monitored for 8 months to 13 years (mean, 5.8 years) revealed LRF patterns to be stable, with changes of not more than two bands. LRF analysis of the seven nosocomial outbreaks with evaluable DNA revealed identical patterns in most or all of the patient isolates and in three outbreaks revealed identity with environmental isolates. These outbreaks included endoscope contamination, postinjection abscesses, and surgical wound infections. LRF analysis of genomic DNA is a useful technique for epidemiologic studies of M. abscessus and M. chelonae, although improved technology is needed for the approximately 50% of strains of M. abscessus with unsatisfactory DNA extractions.

Mycobacterium fortuitum infections of the hand. Report of five cases

Five cases are reported of infection due to Mycobacterium fortuitum involving the hand following contaminated injection or traumatic wounds. Synovectomy, debridement, or amputation together with prolonged chemotherapy using kanamycin or amikacin were required. Doxycycline and sulphamethoxasole also seemed to be the effective antibiotics for this organism. A high index of suspicion is important in order to obtain the correct diagnosis.

Large restriction fragment patterns of genomic Mycobacterium fortuitum DNA as strain-specific markers and their use in epidemiologic investigation of four nosocomial outbreaks

Pulsed-field gel electrophoresis and restriction endonucleases with rare recognition sites were used to generate large restriction fragment (LRF) patterns of genomic DNA from 48 isolates of Mycobacterium fortuitum biovariant fortuitum. Epidemiologically unrelated isolates gave highly diverse patterns when AsnI, HpaI, AflII, DraI, NdeI, XbaI, SpeI, or SspI was used. Epidemiologically related isolates produced identical or minimally different LRF patterns. Minor variations in LRF patterns were seen in two epidemic isolates digested with XbaI, suggesting that genetic alteration had occurred. LRF patterns were used to study three cardiac surgery wound infection outbreaks and one respiratory disease nosocomial outbreak. In two outbreaks, LRF patterns confirmed the reported clustering of isolates on the basis of multiple phenotyping methods. In the remaining two outbreaks, isolates which could not be separated by prior typing methods were easily distinguished by LRF pattern analysis. Environmental water isolates from two outbreaks had LRF patterns identical to those of the disease-producing strains, confirming that the local environment was the source of infection. Pulsed-field gel electrophoresis of LRFs of genomic DNA offers great promise as an epidemiologic tool for the study of M. fortuitum.

Post-surgical nasal cellulitis outbreak due to Mycobacterium chelonae

An outbreak of post-rhinoplasty nasal cellulitis due to Mycobacterium chelonae in a secondary care centre is described. A case-control study demonstrated that the use of inadequately sterilized surgical equipment in the Otorhinolaryngology Department was a risk factor. The causal organism was cultured from the equipment, from the surface of the operating theatre lamp, adhesive tape and from two of the hospital's general water tanks. Introduction of effective instrument sterilization methods, monitored with biological controls, the use of new air filters and cleansing and disinfection of hospital water tanks, were sufficient to control the outbreak. The antimicrobial susceptibilities of the causal organism were consistently different from those previously reported in M. chelonae.

Mercuric reductase activity and evidence of broad-spectrum mercury resistance among clinical isolates of rapidly growing mycobacteria

Resistance to mercury was evaluated in 356 rapidly growing mycobacteria belonging to eight taxonomic groups. Resistance to inorganic Hg2+ ranged from 0% among the unnamed third biovariant complex of Mycobacterium fortuitum to 83% among M. chelonae-like organisms. With cell extracts and 203Hg(NO3)2 as the substrate, mercuric reductase (HgRe) activity was demonstrable in six of eight taxonomic groups. HgRe activity was inducible and required NADPH or NADH and a thiol donor for optimai activity. Species with HgRe activity were also resistant to organomercurial compounds, including phenylmercuric acetate. Attempts at intraspecies and intragenus transfer of HgRe activity by conjugation or transformation were unsuccessful. Mercury resistance is common in rapidly growing mycobacteria and appears to function via the same inducible enzyme systems already defined in other bacterial species. This system offers potential as a strain marker for epidemiologic investigations and for studying genetic systems in rapidly growing mycobacteria.

Mycobacterium chelonei isolation from broncho-alveolar lavage fluid and its practical implications

Mycobacterium chelonei was isolated from the broncho-alveolar lavage fluid of seven patients on eight occasions over a 6-month period. The same bacterium was identified in the hospital water supply. Despite the use of a recommended disinfection procedure, it proved impossible to eradicate the organism until the bronchoscopes were treated with ethylene oxide and the use of tap water in rinsing was abandoned.

Sporotrichoid cutaneous infection due to Mycobacterium chelonei in a renal transplant patient

Atypical mycobacterial infections are becoming more common in dermatological practice due to increasing numbers of immunosuppressed patients. A case of cutaneous Mycobacterium chelonei infection with sporotrichoid spread in a renal transplant patient is described, and the current literature regarding clinical spectrum, histopathology and management of infection with this pathogen is reviewed.

Mycobacterium chelonei infection of a Broviac catheter insertion site

Mycobacterium chelonei infection developed at the insertion site of an indwelling Broviac catheter in a child with erythroleukemia. Direct adherence to and colonization of the intra- and extra-luminal surfaces of the catheter, with extension to the adjacent subcutaneous tissue, by this rapidly growing mycobacterium may have been the primary factor underscoring the infection. Nontuberculous mycobacteria such as Mycobacterium chelonei grow readily on routine bacteriologic media and resemble Corynebacterium spp. (diphtheroids) in their Gram staining and microscopic characteristics. The persistence of the infectious process and a diphtheroid-like microorganism despite antimicrobial therapy should raise the suspicion for a mycobacterial species.

Intraoral infection with Mycobacterium chelonae. A case report

An 8-year-old girl had a visibly enlarged submandibular lymph node and a reddish, spongy swelling of the gingiva in the upper right canine region. Culturing of the gingival tissue resulted in the isolation of Mycobacterium chelonae, and the patient showed a specific skin hypersensitivity reaction to M. chelonae sensitin. The gingival swelling disappeared spontaneously without scarring within 5 weeks after the biopsy. There was no recurrence intraorally during the 2 1/2-year follow-up, the generalized lymphadenopathy subsided within 2 years, and at the last visit, the submandibular lymph node could barely be felt. The patient received no medication during the course of the disease. A tortoise held as a pet by the girl could possibly have been the source of infection since iatrogenic sources of infection could be excluded.

Mycobacterium chelonei peritonitis due to hematogenous dissemination in a continuous ambulatory peritoneal dialysis patient

Renal failure patients have been found to have a special susceptibility to Mycobacterium infections. In patients undergoing peritoneal dialysis, Mycobacterium chelonei peritonitis, due to penetration through the peritoneal catheter lumen, has been described. In our report, we described a case of disseminated M chelonei infection that began in a Thomas hemodialysis prosthesis and finally resulted in peritonitis of hematogenous origin. The diagnostic and therapeutic peculiarities are discussed.

Hand infection with Mycobacterium chelonei

Images

The rapidly growing mycobacteria--Mycobacterium fortuitum and Mycobacterium chelonei

In summary, rapidly growing mycobacteria, M. fortuitum and M. chelonei, are pathogens of increasing importance which are often hospital-acquired and can infect patients with iatrogenic immunosuppression. They readily grow on routine mycobacterial culture media and must be distinguished from non-pathogenic rapidly growing species and slowly growing mycobacteria. Widely distributed in nature, they are often present in hospital environments, especially in water. Compared to M. tuberculosis they are weak pathogens, and infected patients are not considered contagious. Disease is probably acquired from environmental sources by direct entry of the organisms through traumatized skin or mucous membranes or by aspiration into previously abnormal lungs. They are usually resistant to antituberculous agents but are susceptible to several commonly used antibacterial agents. Treatment generally requires one or more active antibiotics plus adjunctive surgery in many cases. Prevention of nosocomial infection lies in proper disinfection of potentially contaminated medical devices and elimination of contaminated water.

Iatrogenic disseminated mycobacterium chelonei infection

The case is presented of a patient who developed a disseminated infection caused by M. chelonei which arose from a fragment of intravascular polyethylene catheter that had been inserted six months earlier.

The immunology of mycobacterial infections

Mycobacteria are endowed with substances that profoundly affect the immune system. Leprosy and tuberculosis exemplify broad spectra of useful and detrimental immune responses of mycobacterial infections that range from intense potentiation to severe specific adn nonspecific suppression of humoral and cellular immune elements. The cellular hypersensitivity induced by mycobacteria serves as a classical model for the analysis of specific and nonspecific immune mechanisms. Mycobacterial disease are prevalent worldwide and rank among the most important bacterial diseases. The kaleidoscope of immunologic events induced by injected mycobacteria and during infections will be reviewed from the standpoint of pathogenesis, pathology, in vitro and in vivo effects on cellular and humoral arms of the immune response, diagnosis, classification, potentiation and suppression.

Bacteria newly recognized as nosocomial pathogens

Bacteria recently recognized as nosocomial pathogens generally fall into three categories: those that grow slowly, those that are fastidious in their nutritional or atmospheric requirements and those that resemble commensals. Each characteristic has contributed to the delay in perceiving their importance. Mycobacterium chelonei and Myco. fortuitum--which grow slowly, although characterized as "rapid-growing" mycobacteria--cause sternal osteomyelitis, pericarditis and endocarditis after cardiac surgery as well as other wound infections after many types of surgery. Myco. chelonei-like organisms have been found to cause "sterile" peritonitis in patients receiving long-term peritoneal dialysis. Legionella pneumophila and L. micdadei are fastidious bacteria that were more difficult to detect because they stain poorly with the Gram method. They cause pneumonia and lung abscess, especially in immunocompromised people. Clostridium difficile is an anaerobe that causes toxin-mediated pseudomembranous colitis in persons given antibiotics that inhibit competing gut bacteria. Chylamydia trachomatis, an intracellular organism that has not been grown in vitro, causes pneumonia and conjunctivitis in young infants who acquire the organism from their mothers at birth. Group JK bacteria cause septicemia in patients whose immune responses have been suppressed and must be distinguished from "diphtheroid" contaminants in blood cultures. Clinicians, microbiologists and epidemiologists must be alert to the characteristics of these organisms that make them easily overlooked and should also anticipate the existence of other bacteria not yet identified.

Radiometric detection of mycobacteria in routine blood cultures

Mycobacterium chelonei subsp. abscessus was detected radiometrically in routine blood cultures. The organism was detected in two patients without the use of special mycobacteriological media.

A pseudoepidemic of pulmonary fungal infections related to fiberoptic bronchoscopy

During a three-week period a pseudoepidemic of fungal infections occurred involving patients from two different services. Trichosporon cutaneum and a Penicillium species were isolated from bronchial washings and sputa obtained after fiberoptic bronchoscopy on eight clinically uninfected patients. Investigation revealed contamination of cocaine solutions used for topical anesthesia during bronchoscopy. Contamination is thought to have occurred during preparation of the solutions by pharmacy personnel. Revision of techniques used in formulating and dispensing the solutions resulted in cessation of the pseudoepidemic.

Tuberculoid cutaneous infection due to a niacin-positive Mycobacterium chelonei

A case of cutaneous infection due to a niacin-positive Mycobacterium chelonei (previously called M. abscessus) on the dorsum of the hand of a professional cotton-classifier is reported from Hong Kong. The infection was probably directly acquired from handling contaminated raw cotton. The patient was successfully treated with combined anti-tuberculous drugs over a period of 1 year. Histologically, the skin lesion showed tuberculoid granulomas, in addition to abscesses.