Pathology of high altitude pulmonary oedema

To describe autopsy findings in fatal cases of high altitude pulmonary oedema. Descriptive study. The study was carried out between 1999 and 2002 at an army field medical unit in Baltistan, Armed Forces Institute of Pathology, Rawalpindi and Army Medical College, Rawalpindi, Pakistan. Autopsies were performed in 17 fatal cases of High Altitude Pulmonary Edema [HAPE] occurring among soldiers serving in Siachen. All cases were males with a mean age of 26.8 years [19-35]. The mean altitude at which HAPE occurred was 5192 meters [2895-6492], and the mean duration of stay at these altitudes was 15.3 days [1-30]. Eleven individuals had undergone proper acclimatization. The commonest clinical findings were cough [70%] dyspnoea [53%], nausea [47%], headache [41%], vomiting [35%], chest pain [35%] and tightness in chest [24%]. Cyanosis and frothy secretions in the nostrils and mouth were present in all but one case. Mean combined weight of lungs was 1470 grams [1070-1810]. There was marked congestion of outer and cut surfaces. Interstitial oedema was present in all cases. RBCs and leukocyte infiltrates were seen in 13 and alveolar hyaline membranes in 9 cases. Thrombi were seen in 2 cases. Cerebral oedema was present in 9 cases. HAPE can occur after more than two weeks of stay at high altitudes despite proper acclimatization. Concomitant cerebral oedema is frequently present. Our autopsy findings are consistent with what has been reported previously

Validity of nalidixic acid screening in fluoroquinolone-resistant typhoid salmonellae

To validate the screening of low-level fluoroquinolone resistance in typhoid salmonellae by using nalidixic acid [30mg] disk providing an acceptable zone of inhibition. Quasi-experimental study. The Department of Microbiology, Armed Forces Institute of Pathology, Rawalpindi, Pakistan from July 2002 to June 2003. Antimicrobial susceptibility of 225 clinical isolates of S. typhi [n=126] and S. paratyphi A [n=99] against nalidixic acid and ciprofloxacin was determined by the modified Kirby-Bauer disk diffusion and agar dilution techniques of NCCLS. The relationship between the zone sizes and the MICs of the two quinolones was plotted in the form of scattergrams and nalidixic acid MICs and zone of inhibition sizes were correlated with those of ciprofloxacin by regression analysis. One hundred and ninety-five isolates were nalidixic acid-susceptible [MIC <16 Mug/mL] and 30 were nalidixic acid-resistant [MIC >32 Mug/mL]. All the nalidixic acid-susceptible isolates had ciprofloxacin MIC of <0.064 Mug/mL. Among the nalidixic acid-resistant isolates 20 had ciprofloxacin MIC > 0.125 Mug/mL and 10 had ciprofloxacin MIC < 0.03- 0.064 Mug/mL. The diameter of inhibition zone around a 30 mg nalidixic acid disk of nalidixic acid-resistant isolates was <13 mm [range 6-16 mm, mean 10.3 mm + SD 3.5 mm], while among nalidixic acid-susceptible isolates it ranged from 14 to 30 mm [mean 23.8 mm + SD 2.2 mm]. The diameter of inhibition zone around a 5mg ciprofloxacin disk of nalidixic acidresistant isolates ranged from 26 to 35 mm [mean 29.8 mm + SD 3.1 mm], while in nalidixic acid-susceptible isolates it ranged from 32 to 42 mm [mean 36.6 mm + SD 1.9 mm]. With ciprofloxacin MIC Z WITH CARON0.125 mg/mL taken as a breakpoint, a zone of <33mm around a 5mg ciprofloxacin disk to detect low susceptibility strains had a sensitivity of 100% and a specificity of 82%. Screening for nalidixic acid resistance [inhibition zone diameter of <13 mm] in isolates with ciprofloxacin MIC Z WITH CARON 0.125 mg/mL using a 30 mg nalidixic acid disk yielded a sensitivity of 100% and a specificity of 95%. Screening for nalidixic acid resistance with a 30mg nalidixic acid disk is a reliable and cost-effective method for detection of low-level fluoroquinolone resistance in typhoid salmonellae

Pattern of systemic fungal infections and antimicrobial susceptibility of isolates in cancer patients

Fungal pathogens are implicated as an important cause of morbidity and mortality in cancer patients. In Pakistan the pattern of systemic fungal infections in cancer patients is not known. The present study was done to determine the pattern of systemic fungal infections and antimicrobial susceptibility of fungal isolates in cancer patients in Rawalpindi. It is a non-interventional descriptive study carried out from May to October 2003 at the Armed Forces Institute of Pathology, Rawalpindi. Blood, urine, stool and sputum specimens were collected for culture isolation of fungi from 73 febrile cancer patients. Antifungal susceptibility of the isolates to amphotericin B, fluconazole and itraconazole was determined by Etest and broth macrodilution technique. Forty-five fungi were isolated from 28 patients. Twenty isolates were Candida albicans, 21 were non-Candida albicans yeasts: C. tropicalis [n=13], C. glabrata [n=5], C. kefyr [n=3], Rhodotorula rubra [n=1] and three were Aspergillus fumigatus. All the isolates of C. albicans were susceptible to itraconazole; one was resistant to fluconazole while 3 isolates showed intermediate resistance to amphotericin B. The non-Candida albicans were generally more resistant: all the isolates of C. kefyr were resistant to amphotericin B, two isolates of C. tropicalis were resistant to fluconazole and three isolates of C. glabrata were resistant to itraconazole. Isolates of A. fumigatus were susceptible to amphotericin B but resistant to fluconazole. Systemic fungal infections in cancer patients by non-Candida albicans are on the rise and they are generally more resistant than C. albicans. Antifungal susceptibility testing must be performed in these cases in order to improve survival and decrease morbidity. Itraconazole can be used for prophylaxis of fungal infections in these patients

Emergence of metallo-beta-lactamase producing Pseudomonas aeruginosa in Pakistan

We report a case of urinary tract infection due to metallo-beta-lactamase producing Pseudomonas aeruginosa resistant to carbapenems. This report signals an ominous development. Unless curbed by judicious use of antibiotics and early detection by screening tests, spread of this plasmid-mediated resistance can render the carbapenems ineffective

Genus and species-specific IgG and IgM antibodies for pulmonary tuberculosis

To evaluate three different enzyme immunoassays for serological diagnosis of pulmonary tuberculosis and to compare their diagnostic accuracy in different combinations. Design: A non-interventional comparative study. Place and Duration of Study: The study was carried out at the Department of Microbiology, Armed Forces Institute of Pathology, Rawalpindi between April and September 2001. Subjects and Sera from patients suffering from pulmonary tuberculosis [n=94] with sputum positive for acid fast bacilli [AFB] and sera from control group of healthy individuals [n=90] with sputum negative for AFB were tested by Pathozyme-Myco G EIA, Pathozyme-TB Complex Plus EIA and Pathozyme Myco M EIA kits for the genus-specific IgG and IgM, and the species-specific IgG antibodies against antigens of Mycobacterium tuberculosis. The detection of IgG against genus-specific antigens by Pathozyme-Myco G had a sensitivity of 46% and a specificity of 93%, of IgG against species-specific antigens by Pathozyme-TB Complex Plus had a sensitivity of 64% and specificity of 97% and of IgM against genus-specific antigens by Pathozyme Myco M had a sensitivity of 67% and specificity of 98%. When the results of these immunoassays were evaluated in combination, their sensitivity improved. Combination of genus-specific IgM and species-specific IgG yielded best results with a sensitivity of 87% and specificity of 93%. The sensitivity of serological diagnosis of tuberculosis is low, but it can be increased by utilizing a combination of several antigens

Central venous catheter-related bloodstream infections in cancer patients

To determine the frequency of central venous catheter-related bloodstream infections [CR-BSI] in cancer patients and the antimicrobial susceptibility pattern of the isolates. Design: A cross-sectional study. Place and Duration of Study: The study was conducted between April 2002 and March 2003 at the Armed Forces Institute of Pathology, Rawalpindi in collaboration with Oncology Units of Armed Forces Bone Marrow Transplant Centre and Combined Military Hospital, Rawalpindi. Subjects and Cancer patients requiring short or long-term central venous catheterization at the time of admission or thereafter were included. Catheter tips on removal were cultured quantitatively; specimens of blood and pus were cultured qualitatively. Isolates were identified and antimicrobial susceptibility testing was performed by standard techniques. Eighty-nine patients were included in the study. The frequency of CR-BSI was 17%. Out of the 19 organisms isolated, 10 [53%] were Gram-positive cocci, 8 [42%] were Gram-negative rods and 1 [5%] was a fungus. Coagulase negative staphylococci [27%] were the predominant pathogens. Among the staphylococci, 46% of the isolates were methicillin-resistant. All Gram-positive isolates were susceptible to glycopeptides. Gram-negative rods were resistant to most of the commonly used antimicrobial groups. Central venous catheter is an important source of bloodstream infections in cancer patients. Most of the infections are caused by Gram-positive cocci. Rigorous infection control measures and continuous surveillance are required to curb the frequency of these infections