Tarek Na'was

Chemical and microbiological investigations of metal ion interaction with norfloxacin

Abstract This report describes a spectrophotometric study on the interaction between norfloxacin (NFX) and metal ions (Al 3+ , Mg 2+ and Ca 2+ ). Two buffers of pH 3.6 and 8.8 were used. A shift in absorption maximum was observed and the stoichiometry of the complex was determined using the Job and molar methods. The ratios were NFX:AL 3+ , 2:1 and 3:1 for the NFX:Mg 2+ complex. The formation of a complex with Al 3+ enhanced the water solubility of the drug. Microbiological studies indicated decreased activity of norfloxacin in the presence of metal ions.

Nasal carriage of methicillin-resistant Staphylococcus aureus by hospital staff in north Jordan

The nasal carriage of methicillin-resistant Staphylococcus aureus was detected in 550 hospital staff members of four hospitals in north Jordan. Of the 109 (19.8%) individuals tested who were nasal carriers of S. aureus, only 32 (5.8%) were found to be carriers of methicillin-resistant Staphylococcus aureus. The carriers were four doctors, 23 nurses, three laboratory technicians, one maid and an administrator. It was noted that 25 (78.1%) of these carriers were in constant contact with patients in operating theatres, surgical wards or intensive care units. It was not clear whether the carriers were short- or long-term carriers, or whether they were persistent sources of methicillin-resistant Staphylococcus aureus. Decontamination of these carriers was considered among other control measures to avoid the dangerous outcome of hospital outbreaks caused by this potential pathogen.

Molecular, antibiogram and serological typing of Staphylococcus aureus isolates recovered from Al-Makased hospital in East Jerusalem

Staphylococcus aureus is a major cause of nosocomial infections and a risk in patients who have either undergone surgery or are on haemodialysis. The S. aureus infections in patients admitted to the clinical departments of Al‐Makased Charitable Hospital in Jerusalem during a period of one year were investigated. Isolates included were from blood, surgical wounds, or other nonsuperficial sites. Of 63 isolates available for analysis, 46 (73.0%) expressed type 8 capsular polysaccharide; 13 (20.7%), type 5 capsular polysaccharide; only 4 isolates (6.3%) did not express type 5 or type 8 antibodies. The strains fitted in 7 different antibiogram types, with the type showing resistance only to penicillin and ampicillin prevalent in 34 out of 63 isolates (54.0%). Of the 12 methicillin‐resistant S. aureus (MRSA) isolates (19.1%), 8(66.7%) possessed the type 8 capsule and 4(33.7%) the type 5 capsule. Pulsed‐field gel electrophoresis of all isolates with the restriction‐endonuclease enzymes Sma I revealed 34 patterns demonstrating that no single methicillin‐sensitive S. aureus strain was endemic in the hospital. However, all MRSA isolates with a type 8 capsule showed identical PFGE patterns using the 2 restriction‐endonuclease enzymes Sma I and SST II. Moreover, type 5 isolates showed identical patterns (one isolate differed from the rest with one band only). These data suggest and confirm the clonality of type 5 and type 8 MRSA isolates. Analysing the results of the capsular and antibiogram typing schemes in conjunction proved useful and suggested that such an analysis can be employed as a helpful epidemiological tool in hospitals with limited resources.

Microbial contamination and preservative efficacy of topical creams

Nineteen different brands of topical creams were tested in duplicate for microbial growth. The efficacy of their preservation was assessed, when possible, by standard pharmacopoeial procedures. Microbial growth was demonstrated in cultures from all specimens. However, high counts (>104c.f.u./g) were obtained from eight specimens from six different brands. The microbes were found to belong to different species of bacteria and fungi including Pseudomonas aeruginosa. Two samples of each of the seven, easily emulsifiable creams, were challenged with standard strains of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans to assess the efficacy of the preservatives used in their preparations. With the exception of a single brand, all creams tested were ineffectively preserved. This study highlights the dangers of marketing domestically prepared topical creams and more effective monitoring of the components for all topical creams is recommended. The inclusion of a proper preservative system in these formulas is essential.

The effect of the pH of various dairy products on the survival and growth of Brucella melitensis

In this study we report the effect of the pH of various dairy products on the survival and growth of Brucella melitensis. The growth patterns of B. melitensis in broth media at different pHs (ranging between 3 and 9) were studied for up to four weeks, to standardize the growth of the organism at each pH. These growth patterns were compared with those of the same organism growing in different dairy products [milk, soft cheese, yoghurt, and buttermilk (shaneena)] under the same growth conditions. This showed that B. melitensis could survive for more than four weeks in broth at a pH of greater than or equal to 5.5, was inhibited in less than three weeks at pH 5 and in one day at pH 4, but could not survive in a pH of less than 4. In dairy products there was a marked drop in the total viable count, and the organism could not be detected after short periods of time. After 72 hours B. melitensis could be detected only in soft cheese, but it was not detectable in any of the dairy products tested after 96 hours. Thus, this study has shown that the survival of B. melitensis in the different dairy products was inversely proportional to the pH of the product.

The role of day care givers in the identification and prevention of infections

The prevalence of nasopharyngeal Streptococcus pyogenes in children attending day care centers in North Jordan was studied. Nasal and throat swabs, cultured for Streptococcus pyogenes were collected from 100 children enrolled in four day care centers serving middle to high socioeconomic status portions of the population in March 1989. The identity of the streptococcal isolates was confirmed by biochemical and serological methods. Throat infection manifestations of the past 3 days, as reported and observed by the care givers, were related to culture results. The study findings showed that the prevalence of nasopharyngeal Streptococcus pyogenes was high and ranged between 10 to 23.3%. It was also noted that the care givers were able to correctly identify children with suspected throat infection, in 11 to 25% of the children who grew Streptococcus pyogenes on cultures, by mere observation of the symptoms. Due to the high prevalence of nasopharyngeal Streptococcus pyogenes in these settings, measures to control and prevent the spread of Streptococcus pyogenes must be employed. This study suggests that care givers may play an important role in achieving such a goal if they are offered proper health education programs and instructions on child hygiene.

MICROBIAL CONTAMINATION and PRESERVATION EFFICACY OF COUGH PREPARATIONS

Cough syrups, manufactured by four different Jordanian pharmaceutical companies, were examined for microbial contents and efficacy of preservation from fungal and bacterial contamination. Five per cent of the tested samples were found to be contaminated by Candida albicans and 30% of the products examined did not comply with the pharmacopoeial requirements for optimal preservation from fungal contamination. All the products tested were free from bacteria and were efficiently preserved against accidental bacterial contamination.

Stereoselective synthesis of new 2,3‐diarylglutaramides and their antibacterial activity

New derivatives of 2,3‐diarylglutamides were prepared in a one‐pot reaction by the hydrolysis of the corresponding diastereomeric pure (R,R) glutaronitriles using concentrated sulphuric acid at room temperature. The structure of the reaction products was established on the basis of their infrared, proton and carbon‐13 NMR spectroscopy as well as by their elemental analysis. The antibacterial activity of both diastereomeric pure glutaronitriles and glutaramides using four standard strains of bacteria is also described.