Polymicrobial infections in patients with Legionella pneumonia]

We assessed the frequency and clinical significance of polymicrobial infections in 31 patients with sporadic community-acquired Legionella pneumonia. Twenty-six patients were men, 5 were women and mean age was 61 years. Eighteen patients were smokers, 6 patients were chronic alcoholics and 23 had underlying diseases. Regarding severity, the illnesses were mild (two patients), moderate (seven patients) and severe (twenty-two patients). In 9 (29%) of the patients, one other etiologic agent for community-acquired pneumonia was identified in addition to the Legionella species. The distribution of one other causal agent was as follows: Mycoplasma pneumoniae, 2 patients; Chlamydia pneumoniae, 2; Chlamydia psittaci, 1; Influenza virus, 1; Streptococcus pneumoniae, 1; Klebsiella pneumoniae, 1; Pseudomonas aeruginosa, 1 patient. Because an antimicrobial agent with activity against Legionella species can also provide coverage for Mycoplasma pneumoniae. Chlamydia pneumoniae, and Chlamydia psittaci, the patients with these coinfections improved without any complications. The patient with influenzavirus coinfection became seriously ill, and the condition was complicated by disseminated intravascular coagulation, renal failure and aspergillus bronchitis. The case of Pseudomonas aeruginosa coinfection was accompanied with a lung abscess and empyema. Our experience illustrates the importance of considering polymicrobial infections in patients with sporadic community-acquired Legionella pneumonia.     

Chlamydia species as a cause of community-acquired pneumonia in Canada.

Chlamydia pneumoniae has been implicated as a cause of community-acquired pneumonia (CAP) in several studies. However, there has been no comprehensive study of the role of Chlamydia species (C. pneumoniae, C. psittaci (avian and feline strains) and C. pecorum) as a cause of CAP. The aim of the present study was to determine the role of C. pneumoniae, C. psittaci and C. pecorum as causes of CAP. A prospective cohort observational study of CAP was conducted at 15 teaching centres in eight Canadian provinces between January 1996-October 1997. Acute (n=539) and convalescent (n=272) serum samples were obtained for determination of antibody titres to C. pneumoniae, C. psittaci, C. pecorum, C. trachomatis, Mycoplasma pneumoniae, Legionella pneumophila serogroups I-VI, Streptococcus pneumoniae and various respiratory viruses. Twelve of 539 (2.2%) patients had acute C. pneumoniae pneumonia and an additional 32 (5.9%) had possible acute infection. C. pneumoniae was the sole pathogen in 16 of 42 (38.1%) of these patients. The most common copathogens were S. pneumoniae, respiratory syncytial virus and influenza virus type A. C. pneumoniae pneumonia patients were older and more likely to show congestive heart failure compared to bacteraemic S. pneumoniae patients. The latter had a lower mean diastolic blood pressure, a higher white blood cell count and a lower arterial carbon dioxide tension. Two patients had antibody titres suggestive of recent infection with the feline strain of C. psittaci. Although numerically Chlamydia pneumoniae is an important cause of community-acquired pneumonia, no distinctive clinical features associated with this pathogen were detected in the present study. Feline Chlamydia psittaci may cause a few cases of community-acquired pneumonia. Avian Chlamydia psittaci should be considered only if there is a compatible epidemiological history.     

Microbial etiology of community-acquired pneumonia in the adult population of 4 municipalities in eastern Finland.

To determine the etiology of community-acquired pneumonia in the adult population of a defined area, specific antibody responses in paired serum samples, levels of circulating pneumococcal immune complexes in serum samples, and pneumococcal antigen in urine were measured. Samples (304 paired serum samples and 300 acute urine samples) were obtained from 345 patients > or =15 years old with community-acquired, radiologically confirmed pneumonia, which comprised all cases in the population of 4 municipalities in eastern Finland during 1 year. Specific infecting organisms were identified in 183 patients (including 49 with mixed infection), as follows: Streptococcus pneumoniae, 125 patients; Haemophilus influenzae, 12; Moraxella catarrhalis, 8; chlamydiae, 37 (of which, Chlamydia pneumoniae, 30); Mycoplasma pneumoniae, 30; and virus species, 27. The proportion of patients with pneumococcal infections increased and of those with Mycoplasma infections decreased with age, but for each age group, the etiologic profile was similar among inpatients and among outpatients. S. pneumoniae was the most important etiologic agent. The annual incidence of pneumococcal pneumonia per 1000 inhabitants aged > or =60 years was 8.0.     

Epidemiology of micro-organisms responsible for community-acquired pneumonia]

Pneumonias occupy a prominent situation among lower respiratory tract infections where they are remarkable for their potential mortality and for our relative knowledge of the responsible micro-organisms. Analysis and synthesis of each series published must answer several questions, such as: what are the lung diseases considered? which investigations have been performed? which criteria of imputability have been used? in which patients has the study been carried out? in which place, which period and which structure? In spite of methodological lacunae and of the inhomogeneous answers to the questions asked, there is some concordance between the series found in the literature. Thus, more than 90% of community-acquired pneumonias with microbiological identification are caused by Streptococcus pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae, Legionella pneumophila, Chlamydia psittaci (or pneumoniae), or Influenza A virus.     

北京地区成人社区获得性肺炎非典型病原体流行病学调查

目的　对引起社区获得性肺炎 (CAP)的病原体进行流行病学调查 ,加强对非典型致病原重要性的认识。方法　收集 2 0 0 1年 11月至 2 0 0 2年 6月CAP患者共 10 3例。分别检测患者急性期及恢复期肺炎支原体、嗜肺军团菌、肺炎衣原体血清抗体。应用聚合酶链反应 (PCR)分别扩增肺炎支原体P1黏附蛋白基因及肺炎衣原体 16SrRNA基因。应用酶免疫测定 (EIA)方法检测尿中嗜肺军团菌抗原。取患者急性期痰标本进行细菌培养 ,应用常规方法分离鉴定细菌。结果　 10 3例CAP患者 ,病原体检出率为 48.5%。 2 3例 (2 2 .3 % )检出肺炎支原体 ,3例 (2 .9% )检出嗜肺军团菌 ,2例 (1.9% )检出肺炎衣原体。 12例分离出肺炎链球菌 (11.7% )、9例分离出流感嗜血杆菌 (8.7% )、7例分离出肺炎克雷伯菌 (6.8% )。 6例患者存在混合感染 (5.8% ) ,其中 5例为肺炎支原体混合其他病原体。结论　非典型病原体尤其是肺炎支原体感染在CAP中占据重要地位 ;肺炎链球菌和流感嗜血杆菌仍为常见的致病细菌 ;混合感染不容忽视     

Atypical pathogens in adult patients admitted with community-acquired pneumonia in Korea

This study examined the prevalence of atypical pathogens causing community-acquired pneumonia (CAP) in Korea. We collected sera and clinical data for a period of 1 year for the adult patients consecutively admitted to Chunchon Sacred Heart Hospital with CAP. The diagnosis was made using serologic methods to detect antibodies for Mycoplasma pneumoniae, Chlamydia pneumoniae, Legionella spp., Chlamydia psittaci, and Coxiella burnetii. Among 81 recruited patients, C. pneumoniae (n = 10, 12.3%) was the leading cause of illness, followed by M. pneumoniae (n = 7, 8.6%). One case of C. burnetii pneumonia was detected, but there were no cases of Legionella spp. or C. psittaci. Three cases of C. pneumoniae pneumonia were co-infected with either M. pneumoniae or C. burnetii. There was no significant difference between atypical pneumonia and non-diagnosed pneumonia in terms of clinical manifestations. In conclusion, of the atypical pathogens causing CAP, C. pneumoniae and M. pneumoniae appear to be the important etiologic pathogens in Korea.     

中国城市成人社区获得性肺炎665例病原学多中心调查

目的 研究引起社区获得性肺炎（CAP）的病原体分布及患者入选前是否应用抗生素、肺炎患者预后研究组（PORT）分级等的情况，同时检测常见病原菌的耐药性。方法 入选2003年12月至2004年11月中国7个城市12个中心的665例CAP患者并进行病原体检测。病原体确定诊断的阳性判断标准为：（1）合格痰标本培养出1株或多株细菌；（2）血培养检出病原体；（3）间隔2～4周采集的2次标本的血清肺炎支原体、肺炎衣原体或嗜肺军团菌抗体滴度呈现4倍或4倍以上增高或降低。应用琼脂稀释法对常见病原菌进行最低抑菌浓度（MIC）检测。结果 在610例同时进行了细菌培养和血清学检测的患者中，肺炎支原体是最常见的病原体，阳性率为20．7％（126例），其后依次为肺炎链球菌10．3％（63例）、流感嗜血杆菌9．2％（56例）、肺炎衣原体6，6％（40例）、肺炎克雷伯杆菌6.1％（37例）、嗜肺军团菌5.1％（31例）、金黄色葡萄球菌3．8％（23例）、大肠杆菌1．6％（10例）、卡他莫拉菌1.3％（8例）、铜绿假单胞菌1．0％（6例）。在195例细菌培养阳性患者中，共有10．2％（62例）合并非典型病原体感染。69株肺炎链球菌，对青霉素、阿奇霉素和莫西沙星的不敏感率分别为20．3％、75．4％和4．3％。结论 非典型病原体尤其是肺炎支原体感染在CAP中占据重要地位；细菌合并非典型病原体的混合感染占10．2％。肺炎链球菌、流感嗜血杆菌仍为常见的致病细菌，我国致CAP肺炎链球菌对大环内酯类抗生素的耐药率高达75．0％以上，对青霉素的不敏感率为20，3％．     

Clinical analysis of community-acquired pneumonia in the elderly

OBJECTIVE: To evaluate the clinical features, etiology, and outcome of patients over 65 years old hospitalized for community-acquired pneumonia. PATIENTS: Eighty-four patients (50 males, 34 females) hospitalized for community-acquired pneumonia in Kawasaki Medical School Kawasaki Hospital between April 1998 and March 2000. RESULTS: Most of the patients had respiratory symptoms or signs, but over one-third also had atypical symptoms of pneumonia such as dyspnea, consciousness disturbance, and gastrointestinal symptoms. The causative microorganisms were identified in 48% of these patients. Streptococcus pneumoniae (13%), respiratory viruses (13%), Haemophilus influenzae (8%) and Mycobacterium tuberculosis (8%) were frequently identified, but Mycoplasma pneumoniae was less frequently noted in the elderly. Double infection was recognized in 19 % and a combination of some virus and bacteria in 13%. Treatment consisted of the administration of second or third generation cephalosporin antibiotics intravenously, because antibiotics had already been preadministered in 39%. The prognosis was poor (mortality rate 9%) for the elderly with community-acquired pneumonia despite mechanical ventilation in 8%. CONCLUSIONS: Although the range of microorganisms causing community-acquired pneumonia differed slightly from that in previous reports; namely, lower frequency of Chlamydia pneumoniae and Legionella pneumophila, it is suggested that the initial antibiotic treatment should always cover S. pneumoniae and H. influenzae. In addition, since a prevalence of virus infections related to the increase in community-acquired pneumonia in the elderly was found in this study, the routine use of influenza vaccine and pneumococcal vaccines in the elderly is recommended to reduce the high mortality rate.     

Diagnosis of atypical pathogens in patients hospitalized with community-acquired respiratory infection

The object of our study was to determine the proportion of atypical respiratory pathogens among patients hospitalized with a community-acquired respiratory infection. From September 1997 to May 1999, 159 patients (57% male, median age 55, range 1-88 y) admitted to 3 regional hospitals for a community acquired respiratory infection, were enrolled in the study. Microbiological diagnosis for the atypical pathogens Mycoplasma pneumoniae, Chlamydia pneumoniae, and Legionella pneumophila was performed with PCR on a throat swab, sputum and/or broncho alveolar lavage (BAL). In addition, Legionella species other than L. pneumophila (L. non-pneumophila species) were detected by PCR. Two serum samples were collected and processed for M. pneumoniae and C. pneumoniae serology. In total, 27 patients (17%) were diagnosed with an atypical pathogen. Infection with M. pneumoniae was detected in 19 patients (12%) (PCR positive n = 7), with C. pneumoniae in 5 patients (3%) (PCR positive n = 0) and with L. pneumophila in 4 patients (2.5%) (PCR positive n = 4). In 54 (34%) patients routine microbiological investigations revealed aetiological agents other than the 3 atypical pathogens, the most frequently diagnosed pathogens being Streptococcus pneumoniae (n = 18), Haemophilus influenzae (n = 17), Gram-negative rods (n = 13), Moraxella catarrhalis (n = 6) and Staphylococcus aureus (n = 6). More than 1 pathogen was found in 13 patients. Atypical pathogens were found more often in the young age group (0-18 y), in contrast to bacterial pathogens that were found more often in the older age groups (> or = 65 y). Atypical pathogens were found less often in patients with a clinical presentation of atypical pneumonia. Legionella species other than L. pneumophila were found by PCR in 13 patients (8%), and in 6 patients in combination with another pathogen. An atypical pathogen (M. pneumoniae, C. pneumoniae or L. pneumophila) was found in 17% of the patients hospitalized with a community acquired respiratory infection, predominantly in the young age group. The role of Legionella non-pneumophila species as pathogen in community acquired respiratory infection needs to be determined. The clinical presentation does not predict the type of pathogen found.     

Chlamydia pneumoniae is an important cause of community-acquired pneumonia in school-aged children: serological results of a prospective, population-based study.

The aetiology of community-acquired pneumonia in childhood was studied in the total population of 8851 children in the area of 4 municipalities in eastern Finland. All cases of community-acquired pneumonia (n = 201) were registered during a surveillance period of 12 months between September 1, 1981 and August 31, 1982. The diagnosis of pneumonia was verified radiologically in all identified cases. The diagnosis of chlamydial infection was based on an antibody response measured by complement fixation (CF), by enzyme immunoassay (EIA; IgG or IgM) or by microimmunofluorescence (MIF; IgG or IgM), and the diagnosis of mycoplasmal infection on CF alone. In total, 29 cases of Chlamydia sp. infection were diagnosed; 20 were caused by Chlamydia pneumoniae. Thus, C. pneumoniae was an aetiological agent in 10%, of the 201 pneumonia cases: the proportion was 9% for children aged 5-9 y and 31% for those aged 10 y or more. In the study population, the total incidence of C. pneumoniae pneumonia was 2.3/1000/y. Mycoplasma pneumoniae serology (CF) was positive in 44 patients (22%); the total incidence of M. pneumoniae pneumonia was 5.0/1000/y. Serological evidence of both Chlamydiae and M. pneumoniae was detected in 9 (41%) patients. Our results indicate that C. pneumoniae is an important cause of community-acquired pneumonia in school-aged children. Diagnostic serological response to Chlamydia species or M. pneumoniae was found in 42% of pneumonia patients between 5 and 9 y of age and in 67% of patients aged 10 y or more. Thus, we suggest that macrolides should be considered as an empirical antimicrobial treatment for community-acquired pneumonia, especially in school-aged outpatients.     

Community-acquired pneumonia. A prospective outpatient study

We initiated a prospective study with a group of practitioners to assess the etiology, clinical presentation, and outcome of community-acquired pneumonia in patients diagnosed in the outpatient setting. All patients with signs and symptoms suggestive of pneumonia and an infiltrate on chest X-ray underwent an extensive standard workup and were followed over 4 weeks. Over a 4-year period, 184 patients were eligible, of whom 170 (age range, 15-96 yr; median, 43 yr) were included and analyzed. In 78 (46%), no etiologic agent could be demonstrated. In the remaining 92 patients, 107 etiologic agents were implicated: 43 were due to "pyogenic" bacteria (39 Streptococcus pneumoniae, 3 Haemophilus spp., 1 Streptococcus spp.), 39 were due to "atypical" bacteria (24 Mycoplasma pneumoniae, 9 Chlamydia pneumoniae, 4 Coxiella burnetii, 2 Legionella spp.), and 25 were due to viruses (20 influenza viruses and 5 other respiratory viruses). There were only a few statistically significant clinical differences between the different etiologic categories (higher age and comorbidities in viral or in episodes of undetermined etiology, higher neutrophil counts in "pyogenic" episodes, more frequent bilateral and interstitial infiltrates in viral episodes). There were 2 deaths, both in patients with advanced age (83 and 86 years old), and several comorbidities. Only 14 patients (8.2%) required hospitalization. In 6 patients (3.4%), the pneumonia episode uncovered a local neoplasia. This study shows that most cases of community-acquired pneumonia have a favorable outcome and can be successfully managed in an outpatient setting. Moreover, in the absence of rapid and reliable clinical or laboratory tests to establish a definite etiologic diagnosis at presentation, the spectrum of the etiologic agents suggest that initial antibiotic therapy should cover both S. pneumoniae and atypical bacteria, as well as possible influenza viruses during the epidemic season.     

Search for agents causing atypical pneumonia in HIV-positive patients by inhibitor-controlled PCR assays.

Pneumonia is one of the most frequent complications in acquired immunodeficiency syndrome-patients with Pneumocystis carinii as the leading cause. The true prevalence of atypical agents such as Chlamydia pneumoniae, C. trachomatis, Legionella pneumophila and Mycoplasma pneumoniae in this population of patients is unknown as the currently used method for diagnosing these agents is measurement of antibody levels. However, this method is of limited value in human immunodeficiency virus (HIV)-positive patients who may have a compromised antibody response. To evaluate the prevalence of Chlamydia spp., Legionella spp. and M. pneumoniae in HIV-infected patients with pulmonary disease, this retrospective study has applied inhibitor-controlled polymerase chain reaction analyses on 103 bronchoalveolar lavage (BAL) fluids representing 103 episodes of pneumonia in 83 HIV-positive patients. L. pneumophila was detected in 1% of the BAL fluids and M. pneumoniae was found as a coexisting pathogen in 2% of the samples. Chlamydia spp. could not be detected in any of the BAL fluids. By culture and staining methods 106 other microorganisms were detected with P. carinii and Streptococcus pneumoniae as the most frequently occurring. Pneumonia due to Chlamydia pneumoniae, Legionella pneumophila or Mycoplasma pneumoniae seems to be rare in Danish human immunodeficiency virus-infected patients, but might be considered as a possible cause in cases of treatment failure.     

Etiology of community-acquired pneumonia: impact of age, comorbidity, and severity.

The aim of this study was to determine the etiology of community-acquired pneumonia (CAP) and the impact of age, comorbidity, and severity on microbial etiologies of such pneumonia. Overall, 395 consecutive patients with CAP were studied prospectively during a 15-mo period. Regular microbial investigation included examination of sputum, blood culture, and serology. Sampling of pleural fluid, transthoracic puncture, tracheobronchial aspiration, and protected specimen brush (PSB) sampling were performed in selected patients. The microbial etiology was determined in 182 of 395 (46%) cases, and 227 pathogens were detected. The five most frequent pathogens were Streptococcus pneumoniae (65 patients [29%]), Haemophilus influenzae (25 patients [11%]), Influenza virus A and B (23 patients [10%]), Legionella sp. (17 patients [8%]), and Chlamydia pneumoniae (15 patients [7%]). Gram-negative enteric bacilli (GNEB) accounted for 13 cases (6%) and Pseudomonas aeruginosa for 12 cases of pneumonia (5%). Patients aged < 60 yr were at risk for an "atypical" bacterial etiology (odds ratio [OR]: 2.3; 95% confidence interval [CI]: 1.2 to 4.5), especially Mycoplasma pneumoniae (OR: 5.3; 95% CI: 1.7 to 16.8). Comorbid pulmonary, hepatic, and central nervous illnesses, as well as current cigarette smoking and alcohol abuse, were all associated with distinct etiologic patterns. Pneumonia requiring admission to the intensive care unit was independently associated with the pathogens S. pneumoniae (OR: 2.5; 95% CI: 1.3 to 4.7), gram-negative enteric bacilli, and P. aeruginosa (OR: 2.5; 95% CI: 0.99 to 6.5). Clinical and radiographic features of "typical" pneumonia were neither sensitive nor specific for the differentiation of pneumococcal and nonpneumococcal etiologies. These results support a management approach based on the associations between etiology and age, comorbidity, and severity, instead of the traditional syndromic approach to CAP.     

非典型病原体所致重症社区获得性肺炎的诊断与治疗

重症社区获得性肺炎病情进展迅速、病死率高,而非典型病原体(如肺炎支原体、肺炎衣原体、军团菌等)是社区获得性肺炎的主要致病菌,因此及时诊断、寻找有效的药物及其他相关治疗手段对及时挽救患者的生命至关重要。文章主要就非典型病原体所致重症社区获得性肺炎的诊断和治疗进行阐述。     

非典型病原菌致成人社区获得性肺炎患者的临床特点分析

目的 研究非典型病原菌感染在成人住院社区获得性肺炎中的重要地位,并对其临床特点进行分析.方法 收集2005年5月至2008年5月来自国内多中心的153例成人社区获得性肺炎住院患者急性期及恢复期双份血清和急性期痰标本,采用间接免疫荧光法检测肺炎衣原体IgG抗体及嗜肺军团菌IgG、IgA及IgM混合抗体滴度,采用被动凝集法检测肺炎支原体IgG、IgA及IgM混合抗体滴度,同时对153份急性期痰标本进行普通细菌培养.用回顾性分析方法了解非典型病原菌在成人社区获得性肺炎住院患者中的地位.结果 153例血清学检测结果中符合非典型病原菌致社区获得性肺炎诊断标准的52例(34.0%),其中47例为单一非典型病原菌感染,其中肺炎衣原体38例,肺炎支原体4例,嗜肺军团菌5例;5例为2种非典型病原菌混合感染,其中肺炎衣原体+肺炎支原体2例,肺炎衣原体+嗜肺军团菌3例;52例中合并细菌感染者11例.结论 非典型病原菌(肺炎衣原体、肺炎支原体及嗜肺军团菌)为成人住院社区获得性肺炎的重要致病菌,以肺炎衣原体为主,同时不能忽视合并细菌感染情况的存在.     

Etiology and outcome of community-acquired pneumonia in relation to age and severity in hospitalized adult patients]

The aim of this study was to determine the etiology and outcome of community-acquired pneumonia (CAP) in relation to age and severity in hospitalized patients. Overall, 652 consecutive patients with CAP were studied retrospectively during a 4-year period from 2002. Severity of pneumonia was classified according to the guidelines of the Japanese Respiratory Society (JRS 2005) and American Thoracic Society (ATS 2001). The etiology was identified in 401 of 652 (61.5%) cases. The four most frequent pathogens were Streptococcus pneumoniae (26.2%), influenza virus (12.4%), Mycoplasma pneumoniae (10.9%), and Haemophilus influenzae (5.9%). The most common pathogen in the younger (15-44 years) group and very severe patients (JRS) was Mycoplasma pneumoniae (38.4%) and influenza virus (28.6%), respectively. The three most frequent pathogens in severe CAP patients (ATS) were Streptococcus pneumoniae (29.0%), influenza virus (17.4%), and Legionella species (13.0%). The overall mortality was 6.4%. The mortality of CAP patients among aged 1544, 45-64, 65-74, and 75 years or older was 1.4%, 3.3%, 6.9% and 9.3%, respectively. The mortality of mild, moderate, severe, and very severe patients (RS) was 0%, 4.1%, 15.5%, and 53.6%, respectively. The mortality of non-severe and severe patients (ATS) was 1.8% and 23.9%, respectively. Age and severity had influence on the prevalence of the main microbial pathogens. Streptococcus pneumoniae remained the most important pathogen that needs consideration in initial antibiotic therapy in patients with CAP of all ages and severities. Pathogens identified in patients with severe CAP in Japan were similar to those of Western countries, except for the high incidence of the influenza virus.     

Is Streptococcus pneumoniae the leading cause of pneumonia of unknown etiology? A microbiologic study of lung aspirates in consecutive patients with community-acquired pneumonia

PURPOSE: Although a wide variety of recognized pathogens can cause community-acquired pneumonia, in many patients the etiology remains unknown after routine diagnostic workup. The aim of this study was to identify the causal agent in these patients by obtaining lung aspirates with transthoracic needle aspiration. SUBJECTS AND METHODS: During a 15-month period, all consecutive patients with community-acquired pneumonia who were eligible for transthoracic needle aspiration were enrolled in the study. In addition to conventional microbial methods (culture of blood and sputum, serologic studies), we performed cultures and genetic and antigen tests for common respiratory pathogens in lung aspirates. RESULTS: The study group consisted of 109 patients. Conventional microbial studies identified an etiology in 54 patients (50%), including Mycoplasma pneumoniae in 19 patients, Chlamydia pneumoniae in 9 patients, and Streptococcus pneumoniae in 9 patients. Among the remaining 55 patients, study of the lung aspiration provided evidence of the causal agent in 36 (65%). In 4 additional patients with a single microbial diagnosis by conventional methods, the lung sample provided evidence of an additional microorganism. The new pathogens detected by lung aspiration were S. pneumoniae in 18 patients, Haemophilus influenzae in 6 patients, Pneumocystis carinii in 4 patients, and C. pneumoniae in 3 patients; other organisms were identified in 4 patients. CONCLUSIONS: In our study, S. pneumoniae was the leading cause of community-acquired pneumonia, accounting for 25% of all cases, including about one-third of the cases the cause of which could not be ascertained with routine diagnostic methods.     

Etiology and management of community-acquired pneumonia in Asia

The causative organisms of community-acquired pneumonia, especially in Japan and Korea, are essentially similar to those in Western countries. If there are any differences, these are due to the laboratory tests and criteria used to define pathogenicity. Overall, Streptococcus pneumoniae is the most frequently occurring pathogen and Haemophilus influenzae, Mycoplasma pneumoniae, Chlamydia pneumoniae and viruses follow. Legionella spp. look likely to be low frequency pathogens in Asian countries, but a reason for this might be limitations of the laboratory tests used. A high frequency of Gram-negative bacilli as pathogens of community-acquired pneumonia in some Asian countries may be due to different criteria used to identify disease-causing organisms. A small number of papers about antibiotic resistance have shown no large differences between Asian countries, but considerable differences to Western countries, such as frequency of macrolide-resistant S. pneumoniae. Some Asian countries have their own guidelines for community-acquired pneumonia, but these are written in their own languages.     

The spectrum of pneumonia in 1983 at the Riyadh Armed Forces Hospital

The agents causing pneumonia have been assessed in 112 adult patients admitted to the Armed Forces Hospital in Riyadh during a period of one year: pathogens were identified in 78 patients (69.6%). Sputum culture produced a significant isolate in 60 patients (53.5%), and in 17 (15.2%) the causative agent was suggested by serological tests. Streptococcus pneumonia was the commonest infecting agent (21.4%). Pneumonia due to Mycobacterium tuberculosis was diagnosed in eight patients, to Mycoplasma pneumoniae in seven, to Chlamydia psittaci in two and to Legionella pneumophila in one. Three renal transplant patients had pneumonia caused by Staphylococcus aureus, cytomegalovirus and Pneumocystis carinii respectively, the latter diagnosed by lung biopsy. Two patients with acute Brucella melitensis infections developed pneumonia. In 34 patients (30.4%) the causative organism was not identified. Most of the epidemiological and aetiological factors studied in this survey are inconsistent with previous reports on pneumonia from western countries. For example, the commonest age group affected was younger than in western series. Tuberculous and brucella pneumonia, not commonly seen in western countries, are diagnoses to be considered in Saudi Arabia.