Short communication: Genetic characterization of antimicrobial resistance in Acinetobacter isolates recovered from bulk tank milk.

A total of 176 Acinetobacter isolates, including 57 Acinetobacter baumannii originally obtained from 2,287 bulk tank milk (BTM) samples in Korea was investigated for the genetic basis of antimicrobial resistance using molecular methods. In addition, the occurrence and cassette content of integrons were examined and the genetic diversity of A. baumannii strains identified was evaluated. Aminoglycoside-modifying enzyme genes were detected in 15 (88.2%) of the 17 aminoglycoside-resistant Acinetobacter isolates tested. The most common aminoglycoside-modifying enzyme gene identified was adenylyltransferase gene aadB (n = 9), followed by phosphotransferase genes aphA6 (n = 7) and aphA1 (n = 5). Of the 31 isolates resistant to tetracycline, tet(39) was detected in 20 of them. The genetic basis of resistance to sulfonamide was identified in 15 (53.6%) of 28 trimethoprim-sulfamethoxazole-resistant isolates and 9 (32.1%) of them carried both sul1 and sul2 genes. A blaADC-7-like gene was detected in 1 ß-lactam-resistant A. baumannii. Furthermore, class 1 integron was identified in 11 Acinetobacter isolates. Two gene cassettes dfrA15, conferring resistance to trimethoprim, and aadA2, conferring resistance to aminoglycosides, were identified in 8 Acinetobacter isolates. None of the isolates was positive for class 2 or class 3 integrons. Pulsed-field gel electrophoresis revealed that most of the A. baumannii strains from BTM samples were genetically diverse, indicating that the occurrence of A. baumannii strains in BTM was not the result of dissemination of a single clone. Elucidation of resistance mechanisms associated with the resistance phenotype and a better understanding of resistance genes may help in the development of strategies to control infections, such as mastitis, and to prevent further dissemination of antibiotic resistance genes. To the best of our knowledge, this is the first report of molecular characterization of antimicrobial-resistant Acinetobacter spp. from milk.

Prevalence and antimicrobial susceptibility of Acinetobacter from raw bulk tank milk in Korea.

The objective of this study was to determine the prevalence of Acinetobacter spp. in bulk tank milk (BTM) samples from different provinces of Korea and to analyze their antimicrobial susceptibility. Altogether, 2,287 BTM samples were investigated. Among them, Acinetobacter spp. were isolated from 176 BTM samples. Out of 176 Acinetobacter spp., 57 isolates were identified as Acinetobacter baumannii. None of the isolates were resistant to cefepime, imipenem, meropenem, ciprofloxacin, levofloxacin, or colistin. Resistance to amikacin, gentamicin, piperacillin, and cefotaxime was 2.3, 7.4, 2.3, and 4.0%, respectively. Acinetobacter spp. were least susceptible to tetracycline (17.6%), followed by trimethoprim-sulfamethoxazole (15.9%), ceftazidime (10.8%), and ampicillin-sulbactam (10.2%). Overall, A. baumannii strains were susceptible to most of the antimicrobial agents tested compared with other Acinetobacter spp. The Acinetobacter isolates showed 17 different patterns of antimicrobial resistance. The most frequent resistance profile observed was ampicillin-sulbactam (n=13), followed by tetracycline (n=9), ceftazidime-tetracycline (n=8), and trimethoprim-sulfamethoxazole-tetracycline (n=8). The results of this study confirmed that Acinetobacter, including A. baumannii strains, are present in BTM, which clearly showed the importance of examining BTM not only for foodborne pathogens but also for Acinetobacter spp., which could be of public health concern. To the best of our knowledge, this is the first report of Acinetobacter spp. in BTM samples from Korea.

Characterization of Candida species isolated from cases of lower respiratory tract infection.

OBJECTIVES: (1) To identify and characterize the Candida species isolates from lower respiratory tract infection. (2) to determine the rate of isolation of Candida species from sputum samples. METHODS: This study was carried out in the Department of Microbiology, Manipal Teaching Hospital, Pokhara, Nepal from June 2002 to January 2003. A total of 462 sputum samples were collected from patients suspected lower respiratory tract infection. The samples were processed as Gram staining to find out the suitability of the specimen, cultured on Sabouraud's Dextrose Agar (SDA) and also on blood agar and chocolate agar to identify the potential lower respiratory tract pathogens. For the identification of Candida, sputum samples were processed for Gram stain, culture, germ tube test, production of chlamydospore, sugar fermentation and assimilation test. For the identification of bacteria, Gram stain, culture, and biochemical tests were performed by standardized procedure. RESULT: Out of 462 samples, 246 (53.24%) samples grew potential pathogens of lower respiratory tract. Among them Haemophilus influenzae 61(24.79%) and Streptococcus pneumoniae 57 (23.17%) were the predominant bacterial pathogens. Candida species were isolated from 30 samples (12.2%). The majority of Candida species amongst the Candida isolates were Candida albicans 21(70%) followed by Candida tropicalis 4(13.33%). Candida krusei 3(10%), Candida parapsilosis 1(3.33%) and Candida stellatoidea 1(3.33%). The highest rate of isolation of Candida was between the age of 71 and 80. CONCLUSION: Candida isolation from sputum samples is important as found in the present study in which Candida species were the third most common pathogen isolated from patients with lower respiratory tract infection.

Prevalence of Moraxella catarrhalis infections of the lower respiratory tract in elderly patients.

OBJECTIVES: To determine: *rate of isolation of Moraxella catarrhalis in elderly patients having lower respiratory tract infection *The antibiotic susceptibility pattern of Moraxella catarrhalis isolates. *The predisposing factors responsible for Moraxella catarrhalis infections of lower respiratory tract. MATERIAL AND METHOD: This is a prospective study carried out at Manipal Teaching Hospital, Pokhara during May 2002 to April 2003. A total of 716 sputum samples collected from patients with suspected lower respiratory tract infection were investigated. The samples were subjected to Gram stain, culture and sensitivity. Sputum samples were inoculated on blood and chocolate agar and incubated at 37 degrees C for 18 to 24 hours in candle jar containing 3-5% Co2. For the identification of bacterial isolates, the cultural and colonial characteristics were recorded and identified with the use of biochemical test. The susceptibility of bacterial isolates to antimicrobial agent was performed following Kirby-Bauer method. RESULT: Out of the 716 samples, 355 (49.58%) grew normal commensals of the upper respiratory tract. Respiratory pathogens were recovered from 361 (50.41%) samples. The most common respiratory pathogen was H. influenzae (26. 86%), followed by S. pneumoniae (21.16%). Moraxella catarrhalis accounted for 6.90%. Rate of isolation of Moraxella catarrhalis was higher in males than in females. Out of 25 isolates 16 were from males and 9 were from females. Frequency of isolation of Moraxella catarrhalis was more frequently seen in age group 61-70 years. It was most commonly recovered in winter. The most effective antibiotics were amoxicillin-clavulanate and ceftriaxone and least was ampicillin. CONCLUSION: Moraxella catarrhalis isolation from sputum especially in persons above 60 years of age and in the absence of other well established pathogens should not be disregarded as they can cause lower respiratory tract infection in these individuals.

An outbreak of El Tor cholera in Kavre district, Nepal.

Outbreak of cholera still remains major public health problem in most of the developing countries including Nepal. A prospective study was carried out at Dhulikhel Hospital, Kathmandu University Teaching Hospital, Kavrepalanchok during 1st May 2004 to 31st October 2004. A total of 148 stool samples from patients with acute diarrhea were collected and further investigated for cholera. The study was conducted to establish the causes of the outbreak of acute diarrheal disease, antimicrobial profiles of the stool isolates and parasitic co-infection in cholera cases. The samples were subjected to standard recommended microbial procedures and confirmation of the isolates was done by seroagglutination using V.cholerae polyvalent O1 and 0139 antisera and monovalent Ogawa and Inaba antisera. Out of the 148 stool samples, 46 cases (31%) were found to be positive for V.cholerae serogroup O1, biotype ElTor, serotype Ogawa. Both sexes were equally affected. Young age group of less than 30 years were mostly affected. Brahmin was the most affected ethnic group. The isolates were sensitive to all the antibiotics tested except co-trimoxazole. Among the laboratory confirmed cholera cases 30% exhibited co-infection with other parasites among which Giardia lamblia and Ascaris lumbricoides were the most common.

Prevalence of Helicobacter pylori in Dhulikhel Hospital, Kathmandu University Teaching Hospital: a retrospective histopathologic study.

OBJECTIVE: The main objective of this study was to determine prevalence of Helicobacter pylori infection in Dhulikhel Hospital, Kathmandu University Teaching Hospital. METHODOLOGY: Endoscopic antral biopsies from January 1, 2004 to August 31, 2005 were studied retrospectively. Hematoxylin and eosin and Giemsa stained histological sections were examined. RESULTS: Out of 224 patients (Male 125 and female 99) who underwent endoscopic biopsy and included in the study, a total of 76 (33.9%) patients (Male 50 and female 26) were infected by H. pylori. The mean age of the H. pylori infected patients was 40.2 years (SD 16.0). The infection by H. pylori was significantly higher in males than females (p<0.05) with male to female ratio of 1.9:1. The most common (31.3%) histopathologic finding was chronic superficial gastritis followed by normal histology (30.8%). A total of 10 cases (4.5%) of adenocarcinoma and 16 cases (7.1%) of intestinal metaplasia were detected and neither of them showed presence of H. pylori. Two cases (0.9%) were diagnosed as suspected malignancy and both were negative for H. pylori infection. Among gastritis, H. pylori was most frequently observed in chronic active gastritis (86.1%). Two of 69 cases (2.9%) of normal gastric mucosa showed H. pylori.

Typhoid fever in Dhulikhel hospital, Nepal.

One hundred and twelve cases of typhoid fever presenting in outpatient and emergency department of Dhulikhel Hospital in Nepal were studied. In this study, it was found that 71% typhoid fever cases were less than 30 years of age group with male to female ratio of 3:1. Fever over 5 days followed by headache and chills were major presenting symptoms. Widal test and blood culture for Salmonella typhi were positive in 59% and 49% cases respectively. Two third of our study population had total leucocyte count of normal range. The fever clearance time was significantly better with ofloxacin compared to ciprofloxacin (p < 0.05) and ceftriaxone compared to chloramphenicol (p < 0.05). The release from treatment was significantly shorter with ceftriaxone compared to ofloxacin, ciprofloxacin and chloramphenicol (p < 0.01). Ceftriaxone was found to be 100% sensitive to salmonella typhi. Amoxicillin was only 52.1% sensitive to Salmonella typhi. Early diagnosis and institution of appropriate antibiotic therapy is of paramount importance in the management of typhoid patients.