Legionnaires' disease caused by Legionella longbeachae and Legionella pneumophila: comparison of clinical features, host-related risk factors, and outcomes.

Legionnaires' disease remains an important cause of mortality and morbidity worldwide. Disease caused by Legionella pneumophila has been extensively studied, and its clinical characteristics have been well described. There is, however, little information on disease caused by Legionella longbeachae, despite its importance in some countries. We undertook a retrospective review of culture-positive cases of Legionnaires' disease in the Canterbury region of New Zealand over 10 years, in order to compare the clinical features and outcomes of Legionnaires' disease caused by these two species.

The worm that turned.

When a patient presents with acute myelopathy in the developed world, helminthic infection is not routinely considered in the differential diagnosis. We report the case of a 34-year-old South African male who presented with acute urinary retention and lower leg paraesthesiae. Subsequently, myeloradiculopathy secondary to Schistosoma mansoni was diagnosed on the basis of typical magnetic resonance imaging changes in the conus medullaris and positive stool microscopy. Prior to this presentation the patient had lived in urban western South Africa and more recently in New Zealand, without exposure to infected water for 22 years. His symptoms and signs resolved following treatment with praziquantel and methylprednisolone. Spinal schistosomiasis is a rare but serious cause of myelopathy and should be considered in any patient who has ever visited or lived in an endemic area.

Lower limb cellulitis: features associated with length of hospital stay.

AIMS: This study aimed to identify features associated with length of hospital stay (LOHS), length of intravenous antibiotic therapy (LIVAT) and six-week outcomes for patients with lower limb cellulitis, and to test the Eron/Passos classification of cellulitis in the New Zealand system. METHODS: Eighty-five variables were collected prospectively from a cohort of 51 inpatients admitted to Christchurch hospital. The primary end-point for analysis was LOHS. LIVAT and six-week outcomes were secondary end-points. RESULTS: On univariate analysis use of diuretics, living alone, cellulitis acuity, a creatinine concentration of >0.1 mmol/l, poor mobility, pulse >90 bpm, age >70 years, oedema extent, chronic oedema, ulceration, neutrophil count >10x10(9)/l, erythema area >1000 cm2 and haemoglobin concentration less than normal were significantly (P= or <0.05) associated with LOHS. A stay of < or =3 days was associated with less oedema, absence of diuretic use and less acute cellulitis. A stay of >7 days was associated with use of diuretics, living alone, age >70 years, more oedema, erythema area >1000 cm2, haemoglobin less than normal, ulceration, creatinine >0.1 mmol/l and poor mobility. The presence of a discharge was associated with LIVAT. Multivariate analysis accounted for 48% of the variance in LOHS and 16% for LIVAT. Use of diuretics, neutrophil count >10x10(9)/l and oedema score were independently associated with LOHS, with oedema score associated with short stay and diuretic use with long stay. The Eron/Passos system was not helpful so a new scoring system was devised which successfully classified patients into length of stay groups. CONCLUSIONS: The clinical features analysed accounted for half of the variance in LOHS. An important reason may be physician discretion. If so, our scoring system based on these results could be used in a clinical pathway to improve patient care. This tool would need to be evaluated prospectively.

CD4+ cytolytic T cells can destroy autologous and MHC-matched macrophages but fail to kill intracellular Mycobacterium bovis-BCG.

Mycobacterium bovis-BCG infected macrophages were exposed in vitro to PPD-stimulated T lymphocytes from tuberculin responsive donors or to a panel of mycobacterial-antigen specific CD4+ T cell clones. Both polyclonal and clonal T cells caused considerable antigen-specific lysis of autologous or MHC class II matched macrophages. However, lysis of infected macrophages did not significantly affect the number of viable mycobacteria which were released into the culture media from lysed macrophages. In tuberculosis, CD4+ cytolytic T cells may be primarily involved in tissue destruction and lack a significant role in acquired cellular immunity.

Lysis of human macrophages by cytolytic CD4+ T cells fails to affect survival of intracellular Mycobacterium bovis-bacille Calmette-Guérin (BCG).

Human CD4+, mycobacteria-specific, cytolytic T cell clones were used to lyse BCG-infected macrophages, and the effect on the subsequent growth and viability of the organisms was examined. The survival of released bacteria following cell lysis was assessed by both 3H-uridine labelling and colony-forming unit (CFU) estimation. The results indicate that even when effective antigen-specific or lectin-mediated cytolysis of the infected macrophages was achieved, there was no evidence for a direct mycobactericidal effect on the intracellular bacteria. This remained the case even if the period of co-culture of T cells and macrophages was extended up to 48 h. Pretreatment of the macrophages with interferon-gamma (IFN-gamma) was not able to act together with T cell-mediated lysis to produce inhibition of mycobacterial growth.

Salmonella and shigella bacteraemia in Zimbabwe.

In patients with HIV infection, non-typhoidal salmonellae are a recognised cause of bacteraemia. This association was initially demonstrated in the United States, but has more recently been found in Kenyan patients. This prompted us to review the cases of patients with enterobacteriaceae bacteraemia admitted to Parirenyatwa Hospital, Harare. Non-typhoidal salmonella bacteraemia as compared with typhoid fever was significantly more common in HIV infected patients than in non-HIV infected patients (p < 0.01). It was also a cause of bacteraemia in patients with other immuno-suppressive conditions and in some patients without identifiable risk factors.

PIP: The case notes of patients with blood cultures positive for enterobacteriaceae were examined retrospectively over a 6-month period in Parirenyatwa Hospital, Harare, Zimbabwe. Speciation was possible for Salmonella typhi and shigellae only. Nontyphoidal salmonellae were serotyped. Salmonella or shigella bacteremia was identified in 51 patients. There were 14 isolates of S. typhi, 32 isolates of nontyphoidal salmonellae, and 5 isolates of shigellae species. The case notes of 38 patients could be identified for review, and of these HIV serology was available for 15 seropositive and 15 seronegative patients. The male to female ratio was approximately 3:1 for both groups and the mean age was 29.7 +or- 21. Nontyphoidal bacteremias as compared with typhoid fever were strongly associated with HIV seropositivity [p 0.01]. 3 out of 8 HIV-negative patients with nontyphoidal bacteremia had another underlying immunosuppressive disease [2 had myeloma and 1 patient had cirrhosis with complicating hepatoma]. 2 patients with nontyphoidal bacteremia whose HIV status was unknown also had another immunosuppressing disease [acute myeloid leukemia and idiopathic pancytopenia]. 13 out of 15 HIV-positive patients showed other signs of HIV infection [oral candida, herpes zoster, persistent generalized lymphadenopathy]. 3 out of 11 patients [27%] with typhoid died, while 11 out of 27 patients [40.7%] with nontyphi bacteremia died. Most strains of S. typhimurium were included in serogroup B, which accounted for 37% of nontyphoidal isolates. Earlier studies identified invasive salmonellosis in patients with other AIDS defining diseases. In Nairobi clinical features of HIV infection were found in 64% of bacteremic HIV-positive patients, but only 28% of patients fulfilled the CDC clinical case definition for AIDS. A more recent study from Nairobi demonstrated that S. typhimurium bacteremia is a common cause of intercurrent infection in HIV-positive tuberculous patients.

Fine-needle extrathoracic lymph-node aspiration in HIV-associated sputum-negative tuberculosis.

HIV-associated tuberculosis is increasingly seen in Zimbabwe and other developing countries. The clinical and radiological features are often atypical, and diagnostic confusion may arise when sputum smears are negative. Patients with suspected intrathoracic tuberculosis frequently have palpable extrathoracic lymph nodes. In this study, Ziehl-Neelsen staining of aspirates from extrathoracic lymph nodes revealed acid-fast bacilli in 20 (71%) of 28 patients with suspected tuberculosis, and 20 (87%) of 23 patients in whom a final diagnosis of tuberculosis was made Aspiration is simple, rapid, and cheap and may be of value in the diagnosis of tuberculosis, especially in developing countries with limited diagnostic and therapeutic resources.

PIP: Between December 1991 and May 1992 physicians included all patients who come to Parirenyatwa Hospital or Harare Central Hospital in Zimbabwe with suspected pulmonary, pleural, or pericardial tuberculosis (TB) in their study to determine the utility of fine-needle aspiration of extrathoracic lymph nodes in suspected intrathoracic TB in identifying HIV-related pulmonary, pleural, or pericardial TB. They conducted fine-needle aspiration in 28 patients with suspected TB. Microscopy revealed acid-fast bacilli in 20 patients (71%). 48 hours after hospital admission, 3 of these patients died even though they received anti-TB chemotherapy. The other 17 responded well to anti-TB chemotherapy. 3 of the 8 patients who had negative lymph-node aspirates for acid-fast bacilli responded to anti-TB therapy, indicating that they probably did indeed have TB. Therefore, fine needle extrathoracic lymph node aspiration followed by staining detected TB in 87% of patients actually ill with TB (20/23). Since the study did not include sputum-positive patients, those with penicillin-responsive fever, and those with obvious palatal or cutaneous Kaposi's sarcoma, the study was somewhat biased. Nevertheless, these results indicated that HIV-associated intrathoracic TB was often associated with extrathoracic tuberculous lymphadenitis. Since fine-needle aspiration is simple, rural hospitals and clinics in developing countries could use it to detect sputum-negative TB and then to determine appropriate therapy. Infection with atypical mycobacteria rarely occurs in Zimbabwe and other African countries, so physicians in Africa should use anti-TB chemotherapy to treat patients with a positive aspirate.

Generation of cytolytic T cells in individuals infected by Mycobacterium tuberculosis and vaccinated with BCG.

BACKGROUND: Macrophage activation by cytokines provides only a partial explanation of antimycobacterial immunity in man. Because cytolytic T lymphocytes have been shown to contribute to immunity in animal models of intracellular infection, the generation of mycobacterial antigen specific cytotoxic T cells was examined in the peripheral blood of patients with tuberculosis. METHODS: Subjects comprised 36 patients with active tuberculosis (18 newly diagnosed) and 32 healthy volunteers, of whom 25 had had BCG vaccination and seven were Mantoux negative. The ability of purified protein derivative (PPD) stimulated peripheral blood lymphocytes to lyse autologous, mycobacterial antigen bearing macrophages was examined by using a chromium 51 release assay. RESULTS: PPD stimulated lymphocytes from normal, Mantoux positive, BCG vaccinated subjects produced high levels of PPD specific cytolysis, whereas lymphocytes from unvaccinated, uninfected subjects caused little or no cytolysis. The generation of cytolytic T lymphocytes by patients with tuberculosis was related to their clinical state. Those with cavitating pulmonary disease or lymph node tuberculosis generated PPD specific lymphocytes with cytotoxic ability similar to that of those from Mantoux positive control subjects, whereas lymphocytes from patients with non-cavitating pulmonary infiltrates showed poor antigen specific cytolysis. After seven days of stimulation with PPD in vitro, lymphoblasts contained both CD4+ and CD8+ cells. Mycobacterial antigen specific cytolysis was restricted to the CD4+ cell population and was blocked by monoclonal antibodies directed against major histocompatibility class II (MHC) antigens. CONCLUSION: CD4+ cytolytic T cells can lyse autologous macrophages presenting mycobacterial antigen and were found in patients with cavitating pulmonary tuberculosis or tuberculous lymphadenitis and in normal, Mantoux positive control subjects. The ability to generate these T cell responses seems to be a marker for response to mycobacteria and may contribute to tissue damage in tuberculosis. These responses do not provide protective immunity against Mycobacterium tuberculosis but may help in disease localisation.

Treatment of typhoid fever and infectious diarrhoea with ciprofloxacin.

Ciprofloxacin and other related fluorinated 4-quinolones have microbiological and pharmacokinetic properties that suggest they could be useful agents in the management of typhoid fever and bacterial gastroenteritis. Initial studies confirm that this is the case. Against fully sensitive Salmonella typhi ciprofloxacin is clinically as effective as chloramphenicol or co-trimoxazole. It is also effective treatment for antibiotic-resistant strains which cause epidemic and endemic infection throughout the world. Furthermore, ciprofloxacin appears to eliminate chronic carriage of Salm. typhi more efficiently than other antibiotics. Ciprofloxacin has excellent in-vitro activity against all the bacterial pathogens that commonly cause infective diarrhoea. There are limited data concerning its use in the treatment of shigella dysentery but, in appropriate situations, ciprofloxacin is effective treatment for salmonella enteritis and is also effective in infections complicated by septicaemia and bone and liver abscesses. Ciprofloxacin appears to be of benefit in Campylobacter jejuni enteritis and is effective in the treatment of travellers' diarrhoea were enterotoxigenic Escherichia coli and shigellae are most important.

Review article: antibiotics and the gut.

Antibiotics have an important place in the management of gastrointestinal disease. Recent studies have demonstrated efficacy in acute bacterial gastroenteritis caused by salmonellae and campylobacteriaceae, shigellae and enterotoxigenic strains of E coli (ETEC). Tetracycline remains effective in cholera. Antibiotic resistance is widespread amongst the enteric pathogens and can quickly spread during epidemics of infective diarrhoeas. It is important that antibiotics are reserved for the treatment of serious infections lest their effectiveness in these conditions be lost. Campylobacter pylori appears to be an important cause of chronic active gastritis and is amenable to treatment with antibiotics and bismuth salts. The role of C. pylori in the pathogenesis of peptic ulcer disease is not yet established but there is mounting evidence that antibiotic treatment will have a place in the treatment of this common condition. The effect of antibiotics on the normal intestinal microflora can have serious consequences. It is a major cause of resistance in urinary tract pathogens, can result in outbreaks of hospital infection with resistant organisms and frequently results in C. difficile associated diarrhoea.

Ethanol lock in the management of catheter occlusion.

Catheter occlusion by lipid material has been associated with the use of lipid containing "all-in-one" compounded solutions during prolonged parenteral nutrition. Previous experience indicated that urokinase is ineffective in clearing such occlusions. We report five patients who developed catheter occlusion with lipid mixes; catheter patency was restored in four by the use of an ethanol solution. No complications were observed, and treatment continued uneventfully in those four subjects.