Time-dependent bacterial air contamination of sterile fields in a controlled operating room environment: an experimental intervention study.

BACKGROUND: Surgical site infections are a global patient safety concern. Due to lack of evidence on contamination, pre-set surgical goods are sometimes disposed of or re-sterilized, thus increasing costs, resource use, and environmental effects. AIM: To investigate time-dependent bacterial air contamination of covered and uncovered sterile goods in the operating room. METHODS: Blood agar plates (N = 1584) were used to detect bacterial air contamination of sterile fields on 48 occasions. Each time, three aerobe and three anaerobe plates were used as baseline to model the preparation time, and 60 (30 aerobe, 30 anaerobe) were used to model the time pending before operation; half of these were covered with sterile drapes and half remained uncovered. Plates were collected after 4, 8, 12, 16, and 24 h. FINDINGS: Mean time before contamination was 2.8 h (95% confidence interval: 2.1-3.4) in the uncovered group and 3.8 h (3.2-4.4) in the covered group (P = 0.005). The uncovered group had 98 colony-forming units (cfu) versus 20 in the covered group (P = 0.0001). Sixteen different micro-organisms were isolated, the most common being Cutibacterium acnes followed by Micrococcus luteus. Of 32 Staphylococcus cfu, 14 were antibiotic resistant, including one multidrug-resistant Staphylococcus epidermidis. CONCLUSION: Protecting sterile fields from bacterial air contamination with sterile covers enhances the durability of sterile goods up to 24 h. Prolonged durability of sterile goods might benefit patient safety, since surgical sterile material could be prepared in advance for acute surgery, thereby enhancing quality of care and reducing both climate impact and costs.

Enrichment and isolation of crude oil degrading bacteria from some mussels collected from the Persian Gulf.

To date, little is known about existing relationships between mussels and bacteria in hydrocarbon-contaminated marine environments. The aim of this study is to find crude oil degrading bacteria in some mussels at the Persian Gulf. Twenty eight crude oil degrading bacteria were isolated from three mussels species collected from oil contaminated area at Persian Gulf. According to high growth and degradation of crude oil four strains were selected between 28 isolated strains for more study. Determination the nucleotide sequence of the gene encoding for 16S rRNA show that these isolated strains belong to: Shewanella algae isolate BHA1, Micrococcus luteus isolate BHA7, Pseudoalteromonas sp. isolate BHA8 and Shewanella haliotis isolate BHA35. The residual crude oil in culture medium was analysis by Gas Chromatography (GC). The results confirmed that these strains can degrade: 47.24%, 66.08%, 27.13% and 69.17% of crude oil respectively. These strains had high emulsification activity and biosurfactant production. Also, the effects of some factors on crude oil degradation by isolated strains were studied. The results show that the optimum concentration of crude oil was 2.5% and the best degradation take place at 12% of salinity. This research is the first reports on characterization of crude oil degrading bacteria from mussels at Persian Gulf and by using of these bacteria in the field the effect of oil pollution can be reduce on this marine environment.

Keratinolytic abilities of Micrococcus luteus from poultry waste

Keratinolytic microorganisms have become the subject of scientific interest due to their ability to biosynthesize specific keratinases and their prospective application in keratinic waste management. Among several bacterial classes, actinobacteria remain one of the most important sources of keratin-degrading strains, however members of the Micrococcaceae family are rarely scrutinized in regard to their applicatory keratinolytic potential. The tested Micrococcus sp. B1pz isolate from poultry feather waste was identified as M. luteus. The strain, grown in the medium with 1–2% chicken feathers and a yeast extract supplement, produced keratinases of 32 KU and lower level of proteases, 6 PU. It was capable to effectively decompose feathers or “soft” keratin of stratum corneum, in contrast to other “hard” hair-type keratins. The produced keratinolytic enzymes were mainly a combination of alkaline serine or thiol proteases, active at the optimum pH 9.4, 55 °C. Four main protease fractions of 62, 185, 139 and 229 kDa were identified in the crude culture fluid. The research on the auxiliary role of reducing factors revealed that reducing sulfur compounds could be applied in keratinolysis enhancement during enzymatic digestion of keratin, rather than in culture conditions. The presented M. luteus isolate exhibits a significant keratinolytic potential, which determines its feasible applicatory capacity towards biodegradation of poultry by-products or formulation of keratin-based feed components.

Production of peptide antibiotics by Bacillus sp: GU 057 indigenously isolated from saline soil

A total of 112 soil samples were taken from differents areas of district D.I.Khan and Kohat (KPK) Pakistan and screened for production of antibiotics against the Micrococcus luteus and Staphylococcus aureus. Widest zone of inhibition (18mm) was produced by microorganism isolated from saline soil. The strain was later identified as Bacillus GU057 by standard biochemical assays. Maximum activity (18mm inhibition zone) was observed against Staphylococcus aureus after 48 hours of incubation at pH 8 and 4% concentration of glucose. The antibiotic was identified by autobiography as bacitracin. The Bacillus strain GU057 was confirmed as good peptide antibiotic producer and can effectively be indulged as biocontrol agent.

Skin decontamination by low-temperature atmospheric pressure plasma jet and dielectric barrier discharge plasma.

BACKGROUND: Over the past few years, plasma medicine has become an important field in medical science. Cold plasma has proven anti-inflammatory, antimicrobial and antineoplastic effects. AIM: To test the decontamination power of two cold plasma sources [low-temperature atmospheric pressure plasma jet (APPJ) and dielectric barrier discharge plasma (DBD)] in vivo on human fingertips. METHODS: After 3, 15, 30, 60, 90, 120, 150, 180, 210 and 240 s of spot treatment with the APPJ and DBD, the log reduction factors (RFs) of physiological (PF) and artificially (AF) contaminated flora (Staphylococcus epidermidis and Micrococcus luteus) were calculated. The bacterial load was determined after counting. Tolerance (paresthesia, pain and heat) was measured using a numerical rating scale. FINDINGS: Both plasma devices led to a significant reduction in PF and AF. The maximum log reduction factors for PF were 1.3 for the DBD at 210 s and 0.8 for the APPJ at 60 s. For AF, the maximum log reduction factors were 1.7 for the DBD at 90 s and 1.4 for the APPJ at 120 s. Treatment with both devices was well tolerated. CONCLUSION: Both the APPJ and DBD were highly effective in eradicating PF and AF from the fingertips of healthy volunteers. No plasma-resistant isolates were observed. Cold plasma appears to have potential for skin disinfection. For hand hygiene purposes, plasma exposure times would need to be reduced significantly by technical means.

Domestic electric drills in the service of orthopaedic surgery: a potential and preventable source of surgical site infections.

OBJECTIVE: We aimed to assess the contamination potential of the exhaust air from venting ports of running domestic electric drills which are commonly used in orthopaedic surgeries by means of both microbiological sampling and particle counting. METHODS: In an empty operating room, the exhaust air from five running sterile domestic electric drills measured using a particle counter and microbiological sampling was made via aspirating isolator with colony formations noted for a 2-week period. International Organization for Standardization (ISO) 14644 criteria were implemented with respect to the sterility standards. RESULTS: All of the drills produced statistically significantly higher levels of particles than the ambient air (p<0.01). There was no statistically significant difference in the number of collected particles among drills (p>0.05). No bacterial growth was detected in microbiological sampling via blood agar medium in the ambient air. Conversely, Staphylococcus epidermidis, Micrococcus luteus, and Staphylococcus capitis were isolated from the exhaust air of all running drills. There was no correlation between the number of particles produced by drills and the microbiological sampling. CONCLUSION: Domestic electric drills are not safe and may be a direct source of surgical site infection, as the use or re-use of these drills during orthopaedic surgery increases the risk of infection with contaminated aerosols that are produced by these devices.

The efficacy and stability of five sanitizing agents challenged with reference microorganisms and clean area isolates / Eficácia e estabilidade de cinco agentes sanitizantes avaliados frente a microrganismos de referência e isolados de áreas limpas

The antimicrobial activity of five sanitizing agents employed in clean areas designated for the pharmaceutical manufacturing of sterile products was tested against nine microorganisms, including four microorganisms from the clean area microbiota. The method consisted of challenging 5 mL of each sanitizing agent - 70% isopropyl alcohol, 0.4% LPH®, 1.16% hydrogen peroxide, 4% hydrogen peroxide, 1% Bioper® and 5% phenol - with 0.1mL each of concentrated suspensions (105 ? 106 CFU/mL) of Staphylococcus aureus, Candida albicans, Corynebacterium sp., Micrococcus luteus, Escherichia coli, Aspergillus niger, Bacillus subtilis, Staphylococcus sp. and Bacillus sp. for 10 minutes, followed by serial dilutions and plating. The results demonstrated that the five agents were effective against S. aureus, C. albicans, Corynebacterium sp., and M. luteus. The same was true of E. coli, except that isopropyl alcohol showed low levels of inactivation. With A. niger, isopropyl alcohol, 0.4% LPH® and hydrogen peroxide were more effective and 5% phenol and 1% Bioper® less effective. 1% Bioper® and 4% hydrogen peroxide showed greater inactivation of Staphylococcus sp., Bacillus sp. and B. subtilis than the other agents. Against S. aureus, C. albicans, Corynebacterium sp. and M. luteus, 5% phenol showed similar activity to other agents, while with A. niger, B. subtilis, Staphylococcus sp. and Bacillus sp., it was similar to or less active than the other agents. It was demonstrated that two microorganisms from the clean area microbiota, Staphylococcus sp. and Bacillus sp., were the most difficult to eradicate, requiring more frequent application of hydrogen peroxide and 1% Bioper® than the other strains.

O objetivo deste estudo é avaliar a atividade antimicrobiana de cinco agentes sanitizantes empregados em áreas limpas construídas para a fabricação de produtos farmacêuticos estéreis contra nove microrganismos, incluindo quatro microrganismos oriundos da área limpa. A metodologia constituiu em desafiar 5 mL de cada agente sanitizante, álcool isopropílico 70%, LPH® 0,400%, peróxido de hidrogênio 1,160% e 4%, Bioper® 1% e fenol 5% com 0,1 mL de suspensão concentrada (105 ? 106 UFC/mL) de Staphylococcus aureus, Candida albicans, Corynebacterium sp., Micrococcus luteus, Escherichia coli, Aspergillus niger, Bacillus subtilis, Staphylococcus sp. e Bacillus sp. individualmente por 10 minutos, seguido de diluições seriadas e plaqueamento. Os resultados demonstraram que os cinco agentes sanitizantes foram efetivos contra S. aureus, C. albicans, Corynebacterium sp., e M. luteus. Os mesmos resultados foram observados com E. coli, exceto para o álcool isopropílico, que demonstrou baixos níveis de inativação. Contra A. niger, álcool isopropílico, 0.4% LPH® e peróxido de hidrogênio foram mais efetivos e fenol e Bioper® menos efetivos. Bioper® e peróxido de hidrogênio 4% demonstraram altos níveis de inativação de Staphylococcus sp., Bacillus sp. e B. subtilis quando comparados com outros agentes. Fenol demonstrou atividade antimicrobiana similar aos outros agentes contra S. aureus, C. albicans, Corynebacterium sp. e M. luteus. Contra A. niger, B. subtilis, Staphylococcus sp. e Bacillus sp., a atividade antimicrobiana do fenol foi similar ou inferior a dos outros agentes. Foi demonstrado que os microrganismos isolados da área limpa, Staphylococcus sp. e Bacillus sp., foram os que apresentaram maior dificuldade para inativar, sendo necessária a aplicação de peróxido de hidrogênio e Bioper® , com maior frequência.

Resistance of bacterial biofilms formed on stainless steel surface to disinfecting agent.

The natural ability of microorganisms for adhesion and biofilm formation on various surfaces is one of the factors causing the inefficiency of a disinfection agent, despite its proven activity in vitro. The aim of the study was to determine the effectiveness of disinfecting substances on bacterial biofilms formed on stainless steel surface. A universally applied disinfecting agent was used in the tests. Bacterial strains: Listeria innocua, Pseudomonas putida, Micrococcus luteus, Staphylococcus hominis strains, were isolated from food contact surfaces, after a cleaning and disinfection process. The disinfecting agent was a commercially available acid specimen based on hydrogen peroxide and peroxyacetic acid, the substance that was designed for food industry usage. Model tests were carried out on biofilm formed on stainless steel (type 304, no 4 finish). Biofilms were recorded by electron scanning microscope. The disinfecting agent in usable concentration, 0.5% and during 10 minutes was ineffective for biofilms. The reduction of cells in biofilms was only 1-2 logarithmic cycles. The use of the agent in higher concentration--1% for 30 minutes caused reduction of cell number by around 5 logarithmic cycles only in the case of one microorganism, M. luteus. For other types: L. innocua, P. putida, S. hominis, the requirements placed on disinfecting agents were not fulfilled. The results of experiments proved that bacterial biofilms are resistant to the disinfectant applied in its operational parameters. Disinfecting effectiveness was achieved after twofold increase of the agent's concentration.

Iron-dependent growth of and siderophore production by two heterotrophic bacteria isolated from brackish water of the southern Baltic Sea.

Iron is indispensable to the growth and metabolism of all marine organisms, including bacteria. In this work, we investigated and compared the influence of iron(III) concentration on the growth of and siderophore production by two heterotrophic bacteria--Micrococcus luteus and Bacillus silvestris. Our results showed that the iron concentration strongly influences the growth of both species. The growth curves were different for each iron concentration and each strain. M. luteus grew more rapidly than B. silvestris, but produced a roughly four times smaller quantity of siderophores. Both M. luteus and B. silvestris secreted hydroxamate-type siderophores and alpha-keto/alpha-hydroxy acids, but did not produce catecholates. This paper is probably the first to report on siderophore production by B. silvestris and M. luteus isolated from seawater. Moreover, the influence of different iron concentrations on the growth of and siderophore production in these bacteria has been documented. This provides further evidence indicating iron bioavailability as the actual reason for siderophore release by biota.

Bacterial contamination in the anterior chamber after povidone-iodine application and the effect of the lens implantation device.

PURPOSE: To assess the incidence of anterior chamber bacterial contamination during cataract surgery, and compare results of injector implantation and forceps implantation of foldable intraocular lenses (IOLs). SETTING: Department of Ophthalmology and Institute of Medical Microbiology, Semmelweis University, Budapest, Hungary. METHODS: This prospective randomized controlled clinical study comprised 97 eyes of 96 patients. Antibiotic eyedrops were not used; however, povidone-iodine 10% solution was used to prepare the eyebrow and eyelids and povidone-iodine 5% to disinfect the ocular surface. A Steri-Drape (3M) was used to surround the eye. Aqueous fluid samples were aspirated from the anterior chamber at the beginning and the end of surgery. The samples were cultured for 14 days under aerobic and anaerobic conditions simultaneously. Cataract surgery was performed using a sutureless, superotemporal, clear corneal phacoemulsification technique. The IOL was implanted with an injector (n = 47) or a forceps (n = 50), with the instrument randomly selected. The frequency of positive bacterial cultures with each implantation method was compared using the Fisher exact test. RESULTS: Bacteria were found in the conjunctival samples in 21 eyes (21.65%) before povidone-iodine application and in 4 eyes (4.12%) after disinfection. The anterior chamber sample before surgery was culture positive for Staphylococcus epidermidis in 2 eyes and for Micrococcus luteus in 1 eye. After surgery, the culture was positive for S epidermidis in 1 eye (2.15%) in the injector group and 1 eye (2.00%) in the forceps group (P = .74). Neither sample came from an eye that had a positive culture preoperatively. There were no intraoperative complications. CONCLUSIONS: In uneventful clear corneal phacoemulsification, meticulous technique can prevent antibiotic use during surgery. No difference in anterior chamber bacterial contamination was found between IOL implantation using an injector or a forceps.

Biodegradation of Maya crude oil fractions by bacterial strains and a defined mixed culture isolated from Cyperus laxus rhizosphere soil in a contaminated site.

Ten bacterial strains were isolated by enrichment culture, using as carbon sources either aliphatics or an aromatic-polar mixture. Oxygen uptake rate was used as a criterion to determine culture transfer timing at each enrichment stage. Biodegradation of aliphatics (10,000 mg L(-1)) and an aromatic-polar mixture (5000 mg L(-1), 2:1) was evaluated for each of the bacterial strains and for a defined culture made up with a standardized mixture of the isolated strains. Degradation of total hydrocarbons (10,000 mg L(-1)) was also determined for the defined mixed culture. Five bacterial strains were able to degrade more than 50% of the aliphatic fraction. The most extensive biodegradation (74%) was obtained with strain Bs 9A, while strains Ps 2AP and UAM 10AP were able to degrade up to 15% of the aromatic-polar mixture. The defined mixed culture degraded 47% of the aliphatics and 6% of the aromatic-polar mixture. The defined mixed culture was able to degrade about 40% of the aliphatic fraction and 26% of the aromatic fraction when grown in the presence of total hydrocarbons, while these microorganisms did not consume the polar hydrocarbons fraction. The proposed strategy that combines enrichment culture together with oxygen uptake rate allowed the isolation of bacterial strains that are able to degrade specific hydrocarbons fractions at high consumption rates.

Gas sensor arrays for early detection of infection in mammalian cell culture.

The detection of bacterial infections in a mammalian cell culture process is realised using a gas sensor array. In production-scale and laboratory-scale cultivations of a perfused recombinant CHO-cell culture producing human blood coagulation Factor VIII, we show that the gas sensor array identifies bacterial contamination earlier than conventional methods. The sensitivity of the instrument is verified by inoculation of a blank cell culture medium with defined bacterial cell counts.

Degradation of anthracene by bacteria isolated from oil polluted tropical soils.

Four bacteria, identified as Pseudomonas aeruginosa, Alcaligenes eutrophus, Bacillus subtilis and Micrococcus luteus were isolated from crude oil polluted soils using anthracene as the sole carbon and energy source. All the organisms utilized n-hexadecane, n-tetradecane, diesel oil, engine oil and naphthalene as sole carbon sources. None could utilize hexane, cycloheptane, xylene, benzene, toluene, phenol, fluoranthene,and kerosene as carbon sources. Highest cell density obtained with 0.1% (w/v) anthracene were 4.5 x 10(7) (cfu/ml), 8.6 x 10(6) (cfu/ml), 5.4 x 10(6) and 2.4 x 10(6) (cfu/ml) respectively, for P. aeruginosa, A. eutrophus, B. subtilis and M. luteus after 30 days incubation. Growth of the organisms on a Nigerian crude oil resulted in a residual oil concentration of 22.2%, 33.3%, 39.3%, 44% and 91.7% respectively, for P. aeruginosa, A. eutrophus, B. subtilis, M. luteus and the noninoculated control on the 14 th day. Ring fission enzymes of the meta pathway were detected in induced cells of P. aeruginosa and A. eutrophus while ortho pathway enzymes were detected in B. subtilis and M. luteus. P. aeruginosa and A. eutrophus had specific catechol-2,3-dioxygenase activities of 3.8 +/- 0.183 and 0.64 +/- 0.032 micromol/min x mg protein respectively while catechol-1,2-dioxygenase activities of 1.95 +/- 0.029 and 1.89 +/- 0.026 micromol/min x mg protein were detected in B. subtilis and M. luteus respectively. This work, highlights the capability of these unreported tropical strains of A. eutrophus, B. subtilis and M. luteus as anthracene degraders.

Ultrastructure of two oil-degrading bacteria isolated from the tropical soil environment.

Two oil-degrading bacteria identified as Pseudomonas aeruginosa and Micrococcus luteus were isolated from crude-oil-polluted soils in Nigeria. The organisms were grown on n-hexadecane and sodium succinate and then examined for the presence of hydrocarbon inclusions. Inclusion bodies were found in n-hexadecane-grown cells and were absent in succinate-grown cells. Formation of hydrocarbon inclusion bodies appears to be a general phenomenon among hydrocarbon utilizers.