Microbial Contamination and Preservative Capacity of some Brands of Cosmetic Creams

PURPOSE: Cosmetic and topical products need not be sterile but may contain low levels of microbial load during use. This study was conducted to determine and compare the level and type of microbial contaminants in commercial cosmetic products sold in the market and a laboratory prepared aqueous cream and their preservative capacities while in use. METHODS: Ten brands of commercially available cosmetic creams and lotions were randomly purchased from the open markets in Benin City. Aqueous Cream was also prepared. Their bacterial and fungal loads as well as types were evaluated. Preservative capacity was evaluated by challenging the creams and lotions with washed and characterized isolates of Staph. aureus and viable counting was performed by the surface viable method. The prepared aqueous cream was similarly challenged with the test organism. RESULTS: All the products were contaminated to varying degrees. Staphylococci and other gram-positive cocci were the most preponderant; gram-negative isolates were hardly found. Fungal contaminants consisted largely of Asp. fumigatus; Penicillium and Microsporium species. Challenge test (re-infection) with Staph. aureus revealed the commercial products as having low capacity for suppressing bacterial proliferation such as may be encountered during in -use contamination. CONCLUSION: Commercial cosmetic creams and lotions evaluated did not generally meet the standards for microbial limits as specified in official monographs. Such products can adversely affect health status of consumers as well as the stability profiles of the products

Consequences of inadvertent microbial contamination of dextrose solutions.

Most intravenous infusion fluids and non-sterile liquid products contain dextrose which serves as a sweetener or an energy source for critically ill or traumatized patients. Hence dextrose was critically examined for stability in the presence of some micro-organism which are commonly known to contaminated i.v. infusion fluids. In the presence of these test organisms, the dextrose component of these solutions was found to be remarkably degraded with average rates of 0.065-3.153% per hour depending on the type of organism. Micro-organisms such as Ps. aeruginosa and E. coli gave low rates of degradation of 0.065-0.88% per hour while the values of 0.770-3.153% per hour were obtained for K. pneumonia; B-lac+ Staph. aureus and B. subtilis. The degradation of dextrose by C. albicans however, increased with dextrose concentration with average rate of 1.147-1.21% per hour. The degradations were gradually accompanied by increases in total acidity and decreases in pH of the dextrose solutions. The variation in the rates of degradation of dextrose by the test organisms is attributable to their survival rates in dextrose solutions and it is of great significance especially at the low inoculum size of 100 cells/ml. The results thus obtained necessitate the maintenance of a high level of aseptic procedures to prevent inadvertent contamination of i.v. fluids and other glucose containing solutions during clinical and other use conditions.

Potential for local and systemic bacterial infection in some occupational groups in Benin City, Nigeria.

BACKGROUND: Many Third World countries may not have adequate facilities for rapid sensitivity testing of antibiotics as an aid to diagnosis and chemotherapy. It may therefore be valuable to relate bacterial carriage on the skin to type of work a person does. METHODS: Given areas of skin in workers from 10 occupational groups were sampled. The bacteria obtained were analyzed after growth on appropriate media. The sensitivity profiles of potential pathogens isolated from these groups, as well as of those (Staphylococcus aureus only) isolated from patients with certified infections, were carried out and the results were analyzed. RESULTS: Staphylococcus aureus constituted the most widely and frequently isolated potential pathogen. Proteus mirabilis, Escherichia coli, and Klebsiella species were also frequent colonizers of skin. There was a statistical relationship between work type and overall prevalence of bacteria on skin (p less than 0.01). Most isolates of the work groups were highly sensitive to gentamicin and cefuroxine but not to penicillin G, ampicillin, and trimethoprim plus sulfamethoxazole; isolates from infected persons were generally more resistant than were the community-acquired ones. CONCLUSIONS: A relationship may exist between the types of bacteria carried on the skin and the type of work in which a person is engaged.

Kinetics of bacterial growth in simple intravenous solutions and admixtures.

The growth of bacteria in intravenous solutions and admixtures has been studied under stationary conditions of incubation. All the solutions were inoculated with 100 organisms/ml, incubated at room temperature (27 degrees C) or (37 degrees C), with samples withdrawn at specified time intervals, and plated in quadruplicates. The simple intravenous (i.v.) solutions did not support significant growth (P greater than 0.05) of any of the micro-organisms. Growth in i.v. solutions containing 1% blood was very significant (P greater than 0.05), as demonstrated by the high apparent growth rate constants (K). The ratio of K for beta-lactamase producing bacteria (beta-lac+) over that for non-beta-lactamase producing bacteria (beta-lac-) was significant (P less than 0.05) at 37 degrees C compared to that at 27 degrees C. The higher K values for B. cereus in benzylpenicillin and cefuroxime solutions, respectively, compared to those in antibiotic-free solutions, may be attributable to hydrolysis of the drugs, while the low K values for B. subtilis in the same solutions may be attributed to the inhibitory effects of the drugs. In conclusion, minute quantities of blood in i.v. solution tend to cause bacteria to multiply rapidly. The presence of beta-lactamase producing species might, in addition, hydrolyse susceptible beta-lactam antibiotics which are common additives to i.v. fluids.

Survival of beta-lactamase-producing and -nonproducing bacteria in intravenous solutions.

The survival of beta-lactamase-producing (beta-lac+) and non-beta-lactamase-producing (beta-lac-) Bacillus and Staphylococcus spp. has been investigated in dextrose 5% injection, NaCl 0.9%, and dextrose 5% in NaCl 0.9% solutions. Tests were performed under static and turbulent conditions of incubation, with and without antibiotics added to the fluids, and with or without 1% citrated blood. All solutions were inoculated with about 1000 organisms/mL, and sampled for viable bacteria at specific time intervals. Under static conditions, there was no significant decrease in viability (p greater than 0.01) of the bacilli, except for the staphylococci (p less than 0.01). However, when cultures were agitated, all species showed significant decline in viability (p less than 0.01). When antibiotics were present, S. aureus (beta-lac+) declined gradually throughout 24 hours (p greater than 0.01). B. cereus (beta-lac+) concentrations were static in all solutions. All organisms multiplied rapidly in solutions containing blood. The results suggest that the growth characteristics of both beta-lac+ and beta-lac- bacteria in intravenous fluids are essentially similar, except in solutions containing beta-lactamase-sensitive antibiotics in which beta-lac+ bacteria tend to survive.

Growth of bacteria in intravenous fluids under stimulated actual-use conditions.

The growth of microorganisms in nonnutritive intravenous solutions under simulated actual-use conditions was studied. Small quantities of Pseudomonas aeruginosa, Staphylococcus aureus, and Klebsiella pneumoniae (final concentration 200-400 cells/ml) were injected into 500-ml containers (glass bottles and plastic bags) of 5% dextrose injection, 0.9% sodium chloride injection, and 5% dextrose and 0.9% sodium chloride injection. Additives (ampicillin, vitamin K, lidocaine, and vitamin B complex) were included in some i.v. solutions. Administration sets were attached to the i.v. containers, and the solutions were run into collection bottles; samples were withdrawn at 0, 1, 2, 3, 4, 5, 6, and 8 hours after contamination and plated for viable counts. Staph. aureus and K. pneumoniae remained viable in 5% dextrose injection and in 0.9% sodium chloride injection, but the numbers of these bacteria did not increase. The number of Ps. aeruginosa declined in all three solutions. In 5% dextrose and 0.9% sodium chloride injection, the number of K. pneumoniae declined but Staph. aureus maintained viability. The type of container and the drug additives had no effect on microbial growth, except that ampicillin was bactericidal to Staph. aureus. Low-level contamination of these bacteria in nonnutritive i.v. solutions under actual-use conditions does not result in large numbers of organisms within the time frame in which most solutions are administered.