Detection of genes for superantigen toxins in methicillin-resistant Staphylococcus aureus clinical isolates in Karachi

To detect genes for enterotoxins, exfoliative and toxic shock syndrome toxins in Staphylococcus aureus [S. aureus] strains isolated from clinical specimens. Cross-sectional observational study. Department of Molecular Genetics, Dr. Ziauddin Hospital, Karachi, from January to December 2010. Two hundred and ninety eight S. aureus clinical isolates were obtained from various clinical samples received at Dr. Ziauddin Hospital, Karachi. Out of these, 115 were detected as methicillin resistant [MRSA] by cefoxitin disk diffusion test showing a prevalence rate of 38.6%. Detection of individual toxin genes was performed by Polymerase Chain Reaction [PCR] by using only one primer pair for each tube. Uniplex primers were preferred as multiplex primers are longer in base pairs and have the potential for cross reaction due to non-specific binding and increase in optimization time. The possession of a single gene or more than a single gene in MRSA isolates was found in 61.73% of clinical samples; the highest number was found in pus swab, followed by sputum, blood, urethral swab, and urine. The prevalence of toxin genes was higher in MRSA as compared to methicillin sensitive [MSSA] isolates [19.12%]. PCR detects strains possessing toxin genes independent of their expression. The possession of genes for super-antigens seems to be a frequent and habitual trait of S. aureus more so in MRSA

five year study of prevalence of helicobacter pylori infection in Karachi, Pakistan

Helicobacter pylori has been found to be associated with chronic active gastritis and gastroduodenal ulcers. Proper diagnosis and treatment can eradicate this organism from the gastric mucosa and reduce the relapse rate of gastroduodenal ulcers. In order to determine the prevalence rate of Helicobacter pylori infection in Karachi, 435 patients referred to the Gastroendoscopy Unit of the Civil Hospital, Karachi were tested for H. pylori infection by culture, Helicourease - rapid urease detection test [IIDRL, Pakistan] and histology. The overall incidence rate of H. pylori infection was found to be 54.94% [239/435] 62.07% [270/435] and 60% [261/435] by culture, Helicourease and histological methods respectively. H. pylori infection was found to be more prevalent in ages 31-50 years. It was also found to be more common in cigarette smokers as well as paan [betal leaf] and niswar [a kind of tobacco] consuming patients. H. pylori was found to be associated with gastritis 70% [35/50], duodenal ulcer 64.38% [94/146], gastric erosion 53.19% [50/94] and gastric cancer 50% [4/8] patient respectively. In the control group, only 33.61% [41-122] of the endoscopically normal patients with the signs and symptoms of the disease tested positive for H. pylori. The most frequent symptoms among H. pylori infected patients were abdominal pain, flatulence, nausea, heartburn and vomiting. Most of the patients who tested positive for H. pylori came from lower socioeconomic areas with poor hygienic standards, and consumed unboiled water which could be a possible source of the bacterium

Breast feeding may protect children against campylobacter jejuni associated diarrhoea

Several new organisms including Aeromonas and Campylobacter jejuni have been added to the list of diarrhoea causing bacterial agents during the last decade. The present study was undertaken to investigate the bacterial aetiology of infantile diarrhoea in Karachi. Effect of different epidemiological factors on the frequency of these infections was also studied. One hundred and eighty rectal swab samples were collected from patients attending the Diarrhoea Unit at the National Institute of Child Health, Karachi and out patient Department of the Abbassi Shaheed Hospital, Karachi, Pakistan. The samples were processed according to standard procedures. C. Jejuni and A. hydrophila were found to be the most common bacterial agents of infantile diarrhoea in Karachi followed by S. typhi and Sh. dysentriae. Breast fed children were found to be completely protected against C. jejuni infection, and they were at a lower risk of other diarrhoea causing bacterial infections as compared to those who were fed by bottle milk. Unboiled water used for the preparation of infant milk formula was found to be the major factor involved in the epidemiology of infectious diarrhoea

Prevalence of herpes simplex virus and associated infections in women with genital problems

An epidemiological study was carried out to determine the prevalence of genital herpes simplex virus [HSV] infection in our adult females by utilizing an amplified enzyme immunoassay [EIA] and microscopic examination of Giemsa stained smears. Deep cervical swabs were collected from 110 females with genital problems attending the Obstetrics and Gynaecology Department at the Abbassi Shaheed Hospital, Karachi. Presence of Neisseria gonorrhoeae and other organisms in association with HSV was also determined by microbiological processing of each specimen. The overall incidence of genital HSV infection was found to be 17.2% by EIA. Intranuclear inclusions were seen only in 6.3% of the Giemsa stained smears. The infection rate among [patients and control] non-pregnant, pregnant and sterile groups was 17.46%, 25% and 15.38% respectively. The mean age of HSV positive cases was 30 years. The majority of females complained of excessive cervical discharge and pain in the lower abdomen. N. gonorrhoeae could not be isolated from any of the HSV positive patients. However, a number of other organisms including E. coli, Moraxella urthrales, Streptococcus agalactiae, Staph. aureus, and Candida albicans were isolated from HSV positive cases. These organisms may have played a role in the severity of infection. A high prevalence of HSV infection in pregnant women [25%] indicated the significance of screening for HSV in order to reduce the risk of neonatal infection. As there was no difference in symptoms recorded in HSV positive and negative cases, it would suggest that such infections cannot be diagnosed on the basis of symptomatology alone

Animal-passage of campylobacter strains with iron-dextran enhances the expression of an outer membrane protein

The outer membrane proteins [OMP] of four C. jejuni/coli isolates have been identified by SDS - PAGE using Sarkosyl extraction of crude membranes. Sarkosyl insoluble fractions of four strains consistently contained a major OMP in the range of 43 k to 48 k, in addition to some minor proteins. SDS - PAGE profile of animal - passed virulence enhanced strains, when compared with the original isogenic strains when compared with the original isogenic strains, revealed the presence of a protein band migrating at 66 k to 68 k in addition to the characteristic major OMP band, suggesting a selective enhancement of this protein during animal passage in presence of iron - dextran. This shift in OMP expression was associated with enhanced virulence of C. jejuni for BALB/c mice. Immunobloting to analyse the antigens in OMP showed antigenicity to the major OMP. The role of the 68 k OMP in the pathogenesis of C jejuni for BALB/c mice remains to be studied