Staphylococcus aureus and MRSA nasal carriage in general population.

OBJECTIVE: Assessment of Staphylococcus aureus (S. aureus) and MRSA nasal carriage in our general population. DESIGN: Cross-sectional analytical study. PLACE AND DURATION OF STUDY: A private Pathology Laboratory in Lahore city from January 2002 to December 2003. MATERIALS AND METHODS: Nasal swabs were obtained from the apparently healthy persons accompanying the patients attending the laboratory. These swabs were inoculated on blood and mannitol salt agar plates and incubated at 37 degrees C. The isolate(s) were identified as S. aureus on the basis of colony morphology, Gram staining, catalase and coagulase tests. Sensitivity to Oxacillin was determined using standard Kirby Bauer technique. RESULTS: Nasal swabs from 1660 subjects from the community were studied. Out of these samples, a total of 246 (14.82%) samples were positive for growth of S. aureus (nasal carriers of S. aureus). Out of 246 S. aureus isolates, 48 (19.51%) isolates were methicillin resistant S. aureus (MRSA). Nasal carriage was higher in males (15.47%) as compared to females (13.26%), in urban areas (16.99%) as compared to rural areas (11.32%) and in the year 2002 (16.02%) as compared to year 2003 (13.08%). However, the difference was significant only for the urban vs. rural comparison (p<0.05). MRSA isolates were also significantly higher among S. aureus isolates from the nasal cavities of urban subjects (22.98%) as compared to rural ones (11.11%). Maximum nasal carriage was present in the age group upto 9 years (20.23%) with decrease in the age groups 10-19, 20-29 and 30-39 years followed by small rise in the older subjects. CONCLUSION: The nasal S. aureus carriage as well as methicillin resistance among these isolates are more common in urban community.

Qualitative assessment of bacteriological quality and chlorination status of drinking water in Lahore.

OBJECTIVE: Qualitative assessment of bacteriological quality and chlorination status of drinking water in Lahore. DESIGN: Descriptive study. PLACE AND DURATION OF STUDY: Lahore city from October 2000 to September 2001. MATERIALS AND METHODS: A total of 2160 water samples from distribution system were tested from nine different localities of Lahore. These localities represented areas with different socioeconomic conditions (SEC). Twenty water samples were tested from each locality from the same taps each month. All the water samples were subjected to H2S strip test for determination of bacteriological contamination as well as orthotolidine test for detection of chlorine. RESULTS: Four hundred and forty-six (20.64%) samples were positive for bacterial contamination. It was observed that contamination was the maximum in low SEC areas (32.22%), followed by intermediate SEC areas (18.47%) and high SEC areas (11.25%). The difference was found to be statistically significant (p<0.01) among different areas. Only 27.73% samples were chlorinated. Positivity of samples for chlorine was the lowest in areas with low SEC(20.69%) and highest (32.77%) in areas with high SEC, the difference being statistically significant. Maximum contamination was present in samples tested during summer months(June-August) of the year (31.11%), followed by autumn months (September-November) of the year (20.9%), spring months (March-May) of the year (18.7%) and winter months (December-February) of the year (11.85%). Samples tested during summer months showed the highest positivity (77.96%) for chlorine (p<0.001) as compared with other months of year. Among chlorinated samples 12.32% showed bacterial contamination. However, contamination was significantly higher (p<0.001) among non-chlorinated samples. CONCLUSION: Bacterial contamination of piped water is a significant problem in Lahore. Regular chlorination and monitoring of water supplies can improve it.

Awareness about causes of gastrointestinal tract (GIT) malignancies.

OBJECTIVE: To determine the knowledge of doctors, nurses, patients and public about the causes of gastrointestinal cancers and dissemination of this knowledge. DESIGN: A cross-sectional analytical study. PLACE AND DURATION OF STUDY: This study was carried out in the Department of Oncology, King Fahad Hospital, Al-Madinah Al-Munawara, Kingdom of Saudi Arabia and was completed in four months from February 2003 to June 2003. SUBJECTS AND METHODS: About 200 doctors, nurses and patients suffering from GIT cancer and general public were selected. Each subject was asked to fill up a proforma designed to assess his knowledge about the risk factors for GIT malignancies. RESULTS: A majority of doctors and nurses had good knowledge about the causes of GIT malignancies. The knowledge of patients and general public was low. Out of all four groups, it was poorest in the patient's group. CONCLUSION: The difference in the knowledge of medicos and patients/public reflects that medicos should convey this knowledge to the patients in particular and general public in general, which is their responsibility besides medical treatment.

Antimicrobial resistance of community and hospital acquired Staphylococcus aureus isolates to oxacillin and glycopeptides.

OBJECTIVE: To determine sensitivity pattern of Staphylococcus aureus isolates from the community and hospitals to methicillin, glycopeptides and other antimicrobial agents. DESIGN: Descriptive study. PLACE AND DURATION OF STUDY: Private Pathology Laboratory in Lahore from January 2001 to April 2002. SUBJECTS AND METHODS: A total of 714 Staphylococcus aureus (S.aureus) isolates from the community and hospital were tested. Community acquired S.aureus strains (n=434) were isolated from specimens like pus from boils/pimples and nasal swabs of patients with asthma attending a local allergy clinic. The hospital acquired S.aureus (n=280) were isolated from specimens like pus from wounds/discharging sinuses, ear swabs, blood and urine. All the isolates were subjected to sensitivity test against Oxacillin, Vancomycin, Teicoplanin, Penicillin, Imipenem, Cefipime and other anti-staphylococcal agents by standard Kirby-Bauer disk diffusion method. Beta lactamase production by all the isolates was also determined by acidimetric test. RESULTS: Significantly higher number of hospital acquired S.aureus isolates (p<0.01) were beta lactamase producing (96.07%) as compared to community acquired (81.79%). Methicillin (Oxacillin) resistance was also higher among hospital strains (31.1%) as compared to community ones (14.1%). No isolate from the community showed resistance to glycopeptides. While 0.3 percent and 0.7 percent of all S.aureus isolates were interpreted as resistant to Vancomycin and Teicoplanin respectively as there was no zone of inhibition. The resistance to these drugs was a bit higher among the MRSA (1.1% and 2.3% respectively). More than 90% of nosocomial MRSA strains were sensitive to Ofloxacin and Fucidic Acid. Resistance to Erythromycin, Lincomycin and Gentamicin was 70.1, 33.3 and 39.1% in that order. In general resistance to different antimicrobial was lower among S.aureus strains of community origin as compared to those of hospital origin. CONCLUSION: Methicillin and multiple drug resistance is quite a significant problem in nosocomial as well as community acquired S.aureus strains. Moreover, it appears that resistance to glycopeptides has also emerged in our nosocomial S. aureus strains. Microbiology laboratories should make efforts not only to regularly screen S.aureus isolates for sensitivity to glycopeptides but also to determine MIC of the isolates.