Pulmonary disease

Bacterial etiology of sputum from tuberculosis suspected patients and antibiogram of the isolates

OBJECTIVE

The current study aims to explore the bacteriology of sputum of tuberculosis (TB) suspected patients. A cross-sectional study was carried out in the sputum samples of 150 TB suspected patients visiting District Public Health Office, Bharatpur, Nepal. The samples were subjected to cultural, microscopic and biochemical analyses for the identification of the isolates. In addition, antibiotic susceptibility tests were carried out with a special focus on ESBL and MBL production following Clinical and Laboratory Standard Institute guidelines.

RESULTS

Bacterial growth was recovered in 47% (71/150) of the TB suspected patients of which 12.66% (19/150) had pulmonary TB infection. Streptococcus spp. (9%) and Pseudomonas aeruginosa (9%) were the most frequently isolated bacteria. Enterobacteriaceae accounted for 35% of the total isolates. Occurrence of bacterial pathogens was more in males (69%) than in females (31%).The incidence of bacterial pathogen was seen associated with gender of the patients and with the TB infection (p < 0.05) but independent with age of the patients and HIV infection (p > 0.05). Tetracycline was effective against Streptococcus spp. whereas gentamicin was effective against Bacillus species. Imipenem and co-trimoxazole were effective drugs for Gram-negative isolates. Among 83 isolates, 35 were multi-drug resistant, 9 were ESBL producers and 4 were MBL producers.

Opportunistic Respiratory Infections in HIV Patients Attending Sukraraj Tropical and Infectious Diseases Hospital in Kathmandu, Nepal

Introduction

Opportunistic bacterial and fungal infections are the major cause of morbidity and mortality among immune suppressed HIV-positive patients. The main objective of this study was to determine bacterial and fungal organisms causing respiratory infections and their susceptibility to commonly prescribed antimicrobials among HIV patients attending a tertiary infectious disease hospital in Kathmandu.

Methods

Sputum samples were collected from the HIV-positive patients attending Sukraraj Tropical and Infectious Disease Hospital (STIDH) from August 2017 to March 2018. A total of 100 sputum samples were cultured on conventional bacterial and fungal culture media. Bacterial and fungal isolates were identified based on their colony characteristics, microscopic morphology and various biochemical tests. Antibiotic susceptibility test (AST) of bacterial isolates was performed by modified Kirby Bauer disc diffusion method.

Results

Out of 100 sputum samples cultured, 24% (n=24) showed bacterial growth, 42% (n=42) showed fungal growth and 10% (n=10) had both bacterial and fungal growth. Among bacteria, 91.6% (n=22) were monomicrobial and 8.4% (n=2) were polymicrobial in growth, of which, Klebsiella pneumoniae (37.5%) were predominant isolates, followed by Pseudomonas aeruginosa (29.2%), and Escherichia coli (16.7%). The antibiotic susceptibility test (AST) showed 68% (17/25) of bacterial isolates were multi-drug resistant (MDR) and among them 41.2% (7/17) were found to be extended spectrum β lactamase (ESBL) producers. Fungal growth was observed in 42% of samples (42/100). A total of six different species of Candida and four different genera of molds were identified. On species differentiation, Candida albicans (20%) were followed by Candida parapsilosis (4%), and Candida dubliniensis (3%); and various molds were Aspergillus fumigatus (4%), Aspergillus flavus (2%), and Penicillium species (5%). CD4 count was inversely associated with bacterial and fungal infections. Fifty percent of the patients with the fungal infections had a CD4 count below 200. No fungal organisms were isolated from HIV-positive patients under antifungal drug treatment.

Conclusion

HIV-positive patients with a CD4 count less than 200 cells/µL are more vulnerable to opportunistic infections of bacterial and fungal origin. Early isolation, identification and appropriate treatment can reduce mortality due to co-infections. Routine screening of opportunistic pathogens is critical to contain the disease progression.

Radiology of pulmonary Mycobacterium avium-intracellulare complex

Although the radiographic appearance of pulmonary MAC infection in the immunocompetent host can be varied, there are several generalizations that can be made. The classic radiographic appearance is indistinguishable from that of pulmonary tuberculosis. The classic form is seen most commonly in males and is typically associated with other predisposing diseases, especially chronic obstructive pulmonary disease. Most patients have upper lobe disease with associated pleural thickening. Widespread disease is common, as is cavitation. Pleural effusions and adenopathy are uncommon. The Lady Windermere syndrome is a special form of pulmonary MAC seen primarily in middle-aged and elderly women. The radiographic findings are bronchiectasis and small nodules, predominately located within the middle lobe and lingula. The combination of bronchiectasis involving exclusively, or primarily, the right middle lobe and lingula is highly suggestive of pulmonary MAC, even in the face of negative sputum cultures. Pulmonary infection with MAC in the immunocompromised patient generally reflects a widespread systemic disease. As such, the radiographic appearance is highly variable. Diffuse pulmonary opacities and adenopathy are common features. Plain radiographs are frequently normal despite active pulmonary infection. Regardless of the clinical situation, pulmonary MAC infection is often omitted from the radiographic differential even when the appearance is characteristic. In general, when pulmonary abnormalities are identified that are consistent with a granulomatous infection, pulmonary MAC needs to be considered along with tuberculosis and fungal infection. Especially with pulmonary MAC, radiographic stability over several years does not exclude active disease. The radiographic appearance may be suggestive of the diagnosis of pulmonary MAC, but correlation with the clinical and microbiological data is necessary to confirm the diagnosis.

Multiple pulmonary nodules in AIDS: usefulness of CT in distinguishing among potential causes

PURPOSE

To determine whether the computed tomographic (CT) appearances of multiple pulmonary nodules in patients with acquired immunodeficiency syndrome (AIDS) can help differentiate the potential infectious and neoplastic causes.

MATERIALS AND METHODS

The thoracic CT scans obtained in 60 patients with AIDS and multiple pulmonary nodules were reviewed retrospectively by two thoracic radiologists who were blinded to clinical and pathologic data. The scans were evaluated for nodule size, distribution, and morphologic characteristics. CT findings were correlated with final diagnoses.

RESULTS

Thirty-six (84%) of 43 patients with opportunistic infection had a predominance of nodules smaller than 1 cm in diameter, whereas 14 (82%) of 17 patients with a neoplasm had a predominance of nodules larger than 1 cm (P <.001). Of the 43 patients with opportunistic infection, 28 (65%) had a centrilobular distribution of nodules; only one (6%) of 17 patients with a neoplasm had this distribution (P <.001). Seven (88%) of eight patients with a peribronchovascular distribution had Kaposi sarcoma (P <.001).

CONCLUSION

In patients with AIDS who have multiple pulmonary nodules at CT, nodule size and distribution are useful in the differentiation of potential causes. Nodules smaller than 1 cm, especially those with a centrilobular distribution, are typically infectious. Nodules larger than 1 cm are often neoplastic. A peribronchovascular distribution is suggestive of Kaposi sarcoma.

The role of fibre-optic bronchoscopy in solid organ, transplant patients with pulmonary infections

Organ transplantation is currently the standard therapy for patients with end-stage organ dysfunction. The immunosuppression caused by this therapy increases the rate of infection, particularly in the lungs. Early diagnosis is extremely important and fibre-optic bronchoscopy is a helpful tool in reaching diagnosis. Knowing the timing of various pathogens following transplantation, and the radiological picture as well as the prophylactic regimen, is helpful when specific pathogens are suspected. Bronchoscopy with bronchoalveolar lavage and transbronchial biopsies are particularly helpful in diagnosis of bacterial cytomegalovirus (CMV) and pneumocytosis carinii pneumocytosis, and is considered a safe procedure. Open lung biopsy is reserved for those who have negative bronchoscopy with a reasonable prognosis.