Prevelance of total coliforms, faecal coliforms and <i>E. coli</i>in Rawalpindi vegetable markets

Nutritional value of vegetables and high prices of meat and meat originated food compel common people to consume plant originated food particularly salad vegetables. Microbial population of vegetable surfaces contains a large number of pathogenic bacteria including members of Enterobactereace like Escherichia coli (E. coli). A survey was conducted in three major markets of Rawalpindi, Pakistan. Tomato, lettuce, cabbage and cucumber samples were collected from three shops of each market. Each vegetable was analysed as unwashed and washed for total coliforms, faecal coliforms and E. coli by FAO (Food Quality Manual). About two hundred and fifty E. coli isolates were preserved, serotyped for presence of O157 serotype. Total coliforms, faecal coliforms and E. coli count exceeded the permissible limits in most samples. The highest Total coliforms were associated with cabbage (3.78 log10 cfu/g). Cucumber was the least contaminated by Total coliforms (2.15 log10 cfu/g). E. coli was detected in tomato, lettuce, cucumber and cabbage. Washed samples showed reduced bacterial population. Seventy six isolates of E. coli were biochemically characterized and serotyped for O157 antigen. A majority of strains could not be identified by serotyping. These findings conclude with high potentially pathogenic microbial load on salad vegetables and urge for preventive action on priority basis.

Rapid detection of coliforms in drinking water of Arak city using multiplex PCR method in comparison with the standard method of culture(Most probably Number)

Objective:To analyse molecular detection of coliforms and shorten the time of PCR.Methods:Rapid detection of coliforms by amplification of lacZ and uidA genes in a multiplex PCR reaction was designed and performed in comparison with most probably number(MPN)method for 16 artificial and 101 field samples.The molecular method was also conducted on isolated coliforms from positive MPN samples;standard sample for verification of microbial method certificated reference material;isolated strains from certificated reference material and standard bacteria.The PCR and electrophoresis parameters were changed for reducing the operation time.Results:Results of PCR for lacZ and uidA genes were similar in all of standard,operational and artificial samples and showed the 876 bp and 147 bp bands of lacZ and uidA genes by multiplex PCR.PCR results were confirmed by MPN culture method by sensitivity 86%(95%CI:0.71-0.93).Also the total execution time,with a successful change of factors,was reduced to less than two and a half hour.Conclusions:Multiplex PCR method with shortened operation time was used for the simultaneous detection of total coliforms and Escherichia coli in distribution system of Arak city.It's recommended to be used at least as an initial screening test,and then the positive samples could be randomly tested by MPN.

Coliforms and Helminth Eggs Removals by Coagulation-Flocculation Treatment Based on Natural Polymers

Wastewater from a municipal wastewater treatment plant (Mexico) was treated by a coagulation-flocculation using natural gums. The residual water was characterized in terms of organic load, and biological contaminants, i.e. total Coliforms (TC), fecal Coliforms (FC) and helminth eggs (HE). The sample has values of 2.8 × 107 MPN/100 ml, 8.48 × 106 MPN/100 ml and 470 HE/L is regarded to TC, FC and HH, respectively. The HE identified in the wastewaters were Diphyllobothrium latum, Ascaris lumbricoides, Hymenolepis nana and Toxocara canis. From several gums, Hydroxypropyl triammonium chloride guar gum (HPTAC-guar) was selected as the most adequate coagulant-flocculant for the class of municipal wastewater (MWW). A diminution of 82% for TC, 94% for FC and 99% for HE was obtained. Besides, the reduction of chemical oxygen demand (COD) and turbidity removals were 46% and 39% respectively. The natural gum mixed with Ca(OH)2, obtained removals of 52% for TC, 100% for HE, 47% for COD and 30% for turbidity.

Evaluation of the Pathogen Detect^®System and Anthracene-Based Enzyme Substrates for the Detection and Differentiation of <i>E. coli</i>and Total Coliforms in Water Samples

Indirect detection of Escherichia coli and total coliforms can be based on the enzymatic activities of β-glucuronidase (β-glu) and β-galactosidase (β-gal). These enzymes utilize the substrates anthracene-β-d-glucuronide and pyrene d-galactopyranoside, respectively. Substrate cleavage by the enzyme releases the soluble fluorescent molecules 2-hydroxyanthracene and 1-hydroxypyrene, which can then be detected by a fluorometer. The Pathogen Detect? system is an automated portable unit that can measure fluorescent enzyme products. In this report, we investigated the utility of the Pathogen Detect? system for potential automation of water quality monitoring. The PDS unit has the ability to detect E. coli, mean 14.7 h at a standard deviation of 1.5, when the sample mean is 9.1 cells in 100 mL with a standard deviation of 12.6. Similarly, total coliforms may be detected at mean 14.7 h with a standard deviation of 1.4 when the sample mean is 59.6 cells in 100 mL, with a standard deviation of 144.5. The PDS unit has the ability to detect single cells of either total coliforms or E. coli in 100 mL water sample within 18 hours. Turbidity and color of water samples have no impact on the detection of E. coli and total coliforms.

Removal of Iron, Coliforms and Acidity from Ground Water Obtained from Shallow Aquifer Using Trickling Filter Method

Ground water is a major source of drinking water. In the Niger Delta, the ground water is unfit for human consumption due to high concentration of iron, coliforms and acidity. In an attempt to make the water potable, groundwater samples were collected from domestic boreholes and analyzed for physicochemical and microbial parameters using standard analytical methods. The groundwater samples were collected after single and double trickling filter treatment. The treated water from the single and double trickling filter was similarly analyzed. Results show that after treatment, iron decreased from 5.23-9.96 mg/L in the raw water to 1.67-2.02 mg/L in the single treatment and 0.05-0.31 mg/L in the double treated water （P 〈 0.05）. Similarly, pH increased from 4.39-5.17 in the raw water to 5.31-5.87 in the single treatment and 6.09-6.90 in the double treatment （P 〈 0.05）. Coliforms decreased from 60-85 MPN/100 mL in the raw water to 3-10 MPN/100 mL in the single treatment and 0-2 MPN/100 mL in the double treatment （P 〈 0.05）. Based on the findings of this study, it is recommended that it is unsafe to drink untreated groundwater as currently practiced in the Niger Delta, but should be subjected to double trickling filter treatment and chlorination before consumption.

Behavior of Antibiotic-Resistant Fecal Coliforms in the Stream of a Sewage Treatment Plant in Tokyo

We are confronting a new threat in the prevalence of antibiotic-resistant bacteria followed by epidemic spread in aquatic environments in metropolitan areas because damage from river floods is increasing remarkably in Japan due to global extreme weather. The sewer penetration rate is about 100% in Tokyo and reclaimed water from sewage treatment plants accounts for over 50% of all water in both the down- and mid-stream areas of local rivers. The water quality of these rivers, which contain microflora, seems to be seriously affected by reclaimed water. In this study, we collected water samples on July 17, 2018 and examined the behavior of antibiotic-resistant fecal coliforms in the stream of a sewage treatment plant in Tokyo. Extended-spectrum β-lactamase (ESBL)-producing fecal coliforms with encoding genes were found;the CTX-M-1, CTX-M-9, TEM, and SHV groups were found to have survived in the final effluent to the river after sterilization with sodium hypochlorite.

Preparation of Reference Material for Proficiency Test for Enumeration of Coliforms in Cheese Matrix

It is widely accepted that quantitative reference materials (RM), are indispensable tools for verification of the precision and accuracy of analytical measurements. The RM can be used by food microbiology laboratories, as part of their quality assurance programmes, to achieve their quality control. In Brazil, Anvisa RDC No. 12/01 specifies the enumeration of coliforms as one of the parameters for evaluating cheese quality. The aim of this study was to produce a quantitative RM for proficiency testing (PT) for use in the testing of enumeration of coliforms in cheese matrixes. A sample of an ultra-filtered cheese with a coliforms count of <3.0 MPN/g and a total n? of viable aerobes of 1.2 × 103 CFU/g was used as the matrix to produce the RM. The ultra-filtered cheese matrix was distributed in flasks, contaminated with a specific concentration of an Escherichia coli strain and submitted to freeze-drying. Sucrose was used as the cryo-protector. The RM produced was considered sufficiently homogeneous and stable at ≤ ?70?C during the entire study period (348 days). The material was also considered sufficiently stable at 4?C for six days, but instable at 30?C and 35?C for the same period. At ?20?C the RM was sufficiently stable for 161 days. It was concluded that the material showed all the necessary requirements for a quality RM to be used as PT items and could be transported to the laboratories taking part in a PT at up to 4?C for up to 6 days, since the results indicated maintenance of the cell concentrations during this period. This is the first study to describe a methodology for producing RM containing coliforms in a cheese matrix.

Antimicrobial Resistant Coliforms in Tap Water with Low Free Residual Chlorine Levels in Two Hospitals: Case Study in Gaza, Palestine

Universal access to safe water, whether at households or health centres, is central to achieving the sixth sustainable development goal by 2030. A hospital-based survey was conducted to screen for antimicrobial resistance among coliforms in samples collected from tap water (n = 54) at surgical wards in Gaza and to investigate the association with free residual chlorine and pH levels. Total coliforms (TC) were detected in 48.1% (26/54) of tested samples and FCs were detected in 25.9% (14/54). Free residual chlorine test ranged from zero to 0.2 mg/l (average: 0.08 mg/l), of which more than half of the samples (53.7%) 29/54 showed no free residual chlorine. The mean value of free residual chlorine in samples tested positive for growth on m-Endo (0.03) was lower than the mean for negative samples (0.14). The pH values were within the acceptable range (average: 7.6) and there was a statistically significant variation between the mean of pH values for samples tested positive on m-Endo (7.29) and that tested negative (7.84). Among coliform positive samples, 23.1% (6/26) had coliform isolates with resistance patterns. More than two-thirds of antimicrobial resistant (AMR) isolates were resistant to amikacin, ceftazidime, ceftriaxone, and imipenem. Moreover, 50% of the isolates were resistant to piperacillin-tazobactam. One-third (33.3%) of isolates were resistant to cefoxitin, and fosfomycin, 16.7% were resistant to ciprofloxacin, and nitrofurantoin. Intermediate resistance was shown in 16.7% of the isolates to cefoxitin and ciprofloxacin. The ESBL and carbapenem resistance genes detected in isolates were TEM (66.7%), NDM (33.3%), OXA (25%), blaCTXM (16.7%), and blaCTXM-3 (16.7%). The finding highlighted the level of contamination with AMR coliform in samples collected from tap water and pointed out the importance of managing water safety through identifying the main source of contamination, in addition to maintaining proper water disinfection at healthcare facilities for the patient, staff and environmental safety.

Microbiological Quality Assessment of Mutton in the Saaba District in Ouagadougou, Burkina Faso

Introduction: This study was carried out to assess the quality of sheep meat sold to consumers in Saaba municipality. Methods: A preliminary survey consisted of assessing hygiene and sampling meat in butchers’ stores. To achieve this, 100 sales outlets were surveyed for their hygiene conditions. 25 mutton meat samples were sampled in the three villages in Saaba district and analyzed using conventional microbiological techniques. The analysis consisted of determining the microbiological characteristics. Results: According to the results of this study, 100% of the butchers surveyed were men of the region. Among these men, 13% had secondary education, 46% had primary education and 41% were illiterate. Of the 100 retail outlets visited, 96% of the sellers were unaware of the hygiene rules and the dangers of microorganisms. The microbiological analysis of the samples revealed that 100% of the meat was of unsatisfactory microbiological quality. The average contamination rate by total aerobic mesophilic flora, total coliforms, Staphylococcus aureus and yeasts and molds was 8.93 × 106, 3.12 × 105, 3.69 × 106, and 6.74 × 103 CFU/g respectively. No Salmonella strain was detected in any of the samples analyzed. Conclusion: Our results pointed out the unsatisfactory safety quality of the sheep meat sold in the sheep meat and good hygiene practices.

Performance of a Horizontal Flow Constructed Reed Bed Filter for Municipal Wastewater Treatment: The Case Study of the Prototype Installed at Gaston Berger University, Saint-Louis, Senegal

In Saint-Louis, Senegal, a constructed wetland with horizontal flow reed beds (FHa and FHb) has demonstrated significant efficacy in treating municipal wastewater. Analyzing various treatment stages, the system showed only a slight temperature variation, from an influent average of 26.3°C to an effluent of 24.7°C. Electrical conductivity decreased from 1331 mS/cm to 974.5 mS/cm post-primary treatment, with suspended solids (SS) dramatically reduced from 718.9 mg/L to 5.7 mg/L in the final effluent. Biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) saw a notable decrease, from initial levels of 655.6 mg/L and 1240 mg/L to 2.3 mg/L and 71.3 mg/L, respectively. Nitrogenous compounds (N-TN) and phosphates () also decreased significantly, indicating the system’s nutrient removal capacity. Microbiological analysis revealed a reduction in fecal coliforms from 7.5 Ulog/100ml to 1.8 Ulog/100ml and a complete elimination of helminth eggs. The presence of Phragmites and Typha was instrumental in enhancing these reductions. The system’s compliance with the Senegalese standards for disposal into natural environments, WHO recommendations for unrestricted water reuse in irrigation, and the European legislation for water reuse was established. The effluent quality met the stringent criteria for various classes of agricultural reuse, illustrating the system’s potential for sustainable water management. This wetland model presents a robust solution for water-stressed regions, ensuring environmental protection while supporting agricultural needs. The study calls for ongoing research to further refine the system for optimal, reliable wastewater treatment and water resource sustainability.

Fecal Enterococci Levels in Selected Tributaries of the Pampanga River Basin, Philippines, and Their Relation to Land Use

This study aims to generate data which can be used as a potential starting point for the updating of the Philippine Water Quality Criteria and the determination of the true impact of land use to the fecal contamination of the Pampanga River Basin (PRB), the largest subwatershed of Manila Bay. Levels of fecal indicator bacteria (FIB) were determined in the selected tributaries of the PRB, representing three land use categories, namely, the forest/woodland (control), agricultural and residential lands. FIB were quantified in order to investigate the potential contribution of the selected areas in the fecal contamination of the PRB. The study was conducted in 2021 covering March, May, June, July, and September to represent the dry (March and May) and wet (June, July, and September) seasons. Counts of FIB, namely thermotolerant coliform, E. coli, and enterococci were qualitatively correlated with the results of the ocular survey and key informant interview based on known fecal contributors and their relevant rainfall data. FIB counts of water bodies in the selected agricultural and residential land use categories had Geometric Mean (GM) counts that are statistically greater than those of bodies of water near the representative forest/woodland (control), and exceeded the acceptable GM limits for all FIB, regardless of the season. Notably, the GM values recorded for the waters near the selected forest/woodland (control) passed the water quality criteria for all measured FIB parameters for both seasons. Furthermore, enterococci levels in the control site were statistically lower during the wet season. These initial findings suggest that agricultural and residential land use categories could be major contributors to the unacceptable water quality of tributaries of the Pampanga River Basin. The prevalence of thermotolerant coliforms and E. coli was noted regardless of rainfall and land use, indicating these FIB may not be adequate as water quality indicators. With their ability to survive and persist in fecally contaminated sediments in water bodies and in nutrient-poor environments, enterococci could be more definitive indicators of fecal contamination and microbiological quality of environmental waters.

Assessment of Drinking Water Quality Served in Different Restaurants at Islam Nagor Road Adjacent to Khulna University Campus, Bangladesh

Potable water is a growing requirement for sound health as contaminated water and water-borne pathogens pose serious health risks to human beings. Considering this issue, the current study aimed to assess the drinking water quality served in different restaurants close to the Khulna University campus in Bangladesh. A total number of ten drinking water samples were collected from different restaurants. Afterward, the collected water samples were analyzed to examine the physico-chemical properties and microbiological contamination of the water samples. Besides, microbial properties such as Total Coliform (TC), Fecal Coliform (FC), and E. coli were analyzed by the Membrane Filtration (MF) technique. The findings suggest that all the physico-chemical attributes were within the permissible limits regarding recommended Bangladesh standards and WHO guidelines. But in case of EC, 40% of the samples exceeded the WHO permissible limits and for sodium, 10% of samples exceeded both the BD and WHO standards. In addition, the results disclosed that the drinking water served in different restaurants was contaminated by TC, FC, and E. coli. It is observed that 100% of the samples were contaminated by TC and FC whereas 70% of the samples were contaminated by E. coli. Consequently, it is clearly evident that the water is considered suitable with respect to physico-chemical analysis but this drinking water is unfit for consumption while taking into account its microbiological quality. The total coliform, fecal coliform, and E. coli count attests to the fact that anyone can become harmed at any moment by ingesting water from roadside restaurants. Finally, due to bacterial contamination, the served drinking water in these places doesn’t meet safe and suitable water excellence, therefore, consumption of this water is deleterious to public health.

Prevalence and Antimicrobial Susceptibility Status of Gram-Negative and Gram-Positive Bacteria on Handheld Shopping Trolleys and Baskets in Supermarkets in Ndola, Zambia

Background: Supermarkets are a place visited by individuals with different health conditions daily where microbiological contaminants through touch onto fomites such as trolleys and baskets can be passed on to other people hence potentially spreading infectious diseases. This study aimed to investigate the presence of Gram-negative and Gram-positive bacteria on handheld shopping trolleys and baskets and their antimicrobial susceptibility status against commonly used antibiotics in Zambia. Methods: A cross-sectional study was conducted. Trolleys and basket handles were swabbed and standard microbiological methods were used to identify the bacteria and disc diffusion to determine their antimicrobial susceptibility status. Data was collected from December 2021 to April 2022. Data was analysed using IBM Statistical Package for Social Sciences (SPSS) Version 22. Results: Twenty-eight percent of the 200 total samples were found to be culture-positive and predominant isolates were Staphylococcus aureus (17.3%), Pseudomonas species (4.5%), Escherichia coli (2%), Corynebacterium species (2%), Staphylococcus species (1.5%) and Enterobacter aerogenes (0.5%). Staphylococcus aureus showed the most resistance to azithromycin (17%) followed by ciprofloxacin (2.8%), nitrofurantoin (2.8%) and chloramphenicol (2.8%). Escherichia coli showed 100% resistance to amoxicillin, cloxacillin and ampicillin, 75% resistance to ciprofloxacin and the least resistance to azithromycin (25%) while it was susceptible to nitrofurantoin. Staphylococcus species, Corynebacterium species, Enterobacter aerogenes and Pseudomonas species showed no resistance to any antibiotics. Conclusion: The study showed the presence of microorganisms with considerable antimicrobial resistance to antibiotics in Zambia on trolley and basket handles indicating the need for more initiatives to address proper hygiene in public environmental sites for better infection prevention and control.

Microbiological Quality of Freshly Prepared, Packaged Fruit and Milk Juices Sold in Cafés, Shops, and Supermarkets in Hargeisa, Somaliland

Background: Due to their delicious taste, high nutritional content, and health benefits, fruit juices are well-known drinks in many countries and are now an essential component of the modern diet. Objective: Determining the microbiological quality of both packaged and freshly made fruit and milk juices. Method: The spread-plate approach was employed to isolate and count the bacteria. 90 ml of sterile peptone water were blended with 10 ml of well-mixed, packed, and freshly made fruit juices. The samples were sequentially diluted (101 - 105) in accordance with the Indian Manual of Food Microbiological Testing Methods. Results: From eight samples of imported packaged fruit and milk juice, the average of total coliform, staphylococci, and viable bacterial counts were zero, 1.39 × 102, and 2 × 102 CFU/ml, respectively. In contrast, from three samples of locally produced fruit and milk juice, the average of total coliform, staphylococci, and viable bacterial counts were zero, 5.83 × 102, and 2.73 × 103 CFU/ml, respectively. Four samples of handmade prepared fruit and milk juices had a mean of total coliform, staphylococci, and viable bacterial count of 1.441 × 104, 4.1 × 103, and 2.35 × 105 CFU/ml, respectively. Conclusion: 33.3% of the results from microbiological analysis of freshly made fruit and milk juices met the permissible range of the Revised Microbiological Standards for Fruit and Vegetables and Their Products, which were published in 2018 and as well as the Hong Kong Center for Food Safety, whereas 66.7% of the microbiological analyses of freshly prepared fruit and milk juices were above the permissible reference range of GSO standard 2000. 12.5% of the investigated imported and packed fruits and milk juices had one failed test (TSC), which was above the acceptable limit, 87.5% of the tested samples of fruit and milk juices fulfilled the necessary standards of TCC, TVBC, and TSC. 100% of the tested locally manufactured fruit and milk juices complied with TSC, TCC, and TVBC requirements. All investigations showed that freshly made fruit and milk juices were heavily contaminated (Total viable bacterial count, total coliform count, and total staphylococcus count). .

Effect of Disinfection Time on Microbial Content and Quality of Cold Fresh Chicken

[Objective] The aim was to provide reference for the production technolo- gy of cold fresh chicken. [Method] Lactic acid was used as the disinfectant in cooling water, so as to study the effect of disinfection time on the microbial content and quality of cold fresh chicken. [Result] With disinfection of 20 min, the removal rates of the total colonies, coliforms and moulds reached over 95%. As the disinfec- tion time was further extended, it had no significant effect on the removal effects of the microbial content and could affect the tenderness and color of cold fresh chick- en. [Cendusion] The study provides references for the design and optimization of the production process of cold fresh chicken.

The Bacterial Load of Hospital Discharges(Sidi Kacem,Morocco)

Fecal microorganisms, which are indicators or pathogens, have an optimum growth in the specific conditions of the internal environment animal or human. Therefore, when issued by a host, they result in sudden and drastic changes in the environment. This study aims at bacteriological characterization of the effluent from the provincial hospital in Sidi Kacem. And it shows that the effluent from the hospital contributing to non-regulatory standards ultimately reaches the environment (river wadi floor, animal, vegetable...). The results of bacteriological analyses (Total Coliforms, Fecal Coliforms) about sewage from the provincial hospital depending on the day of rest and work in the city of Sidi Kacem are presented with means respectively 557 × 104 and 328 × 104 in the rest and working days 555 × 104, 342 × 104 and the much higher maximum working days from the day of rest are 64 × 105 and 42 × 105. The results obtained show that the rate of bacteria (CT-CF) exceeds standards recommended by CNS (1994) and WHO (1996, 1997). These results have adverse effects on human life, animal, environment and ecosystem in general.

Investigation of fecal coliform and typical enteric virus in representative beaches of China

Through investigating ten recreational marine beaches in China, we aimed to detect the occurrence of human enteric viruses in coastal bathing beaches and find a correlationship, if any, between the presence of enteric viruses in surface seawater and the concentrations of fecal coliforms, the conventional indicator of fecal pollution. In this study, twenty seawater samples were assayed for fecal coliforms and human pathogenic enteric viruses （hepatitis A viruses, rotaviruses, polioviruses） analysis. Enteric viruses were detected by RT-PCR, in 20 sample sites, 5%, 40%, 40% were positive for the presence of human hepatitis A viruses, rotaviruses, polioviruses, respectively. Seven of 20 sites are suffering from severe fecal contamination, based on traditional plate counts of fecal coliform outnumbering the established thresholds for recreation. Additionally, statistical analysis presented that no correlation was found between bacterial indicators and viruses in surface seawaters. The data confirmed that indicator bacteria in water are not reflective of the presence of enteric viruses in marine waters. Thus, current recreational water quality standards of both bacterial and viral indices should be reevaluated.

日粮中添加甲酸钙和酸性蛋白酶对断奶仔猪生产性能的影响

本研究探讨玉米 豆粕 乳清粉型日粮中添加甲酸钙和酸性蛋白酶对断奶仔猪生产性能的影响 ,试验采用 2× 2完全随机设计 ,2 8d研究表明 :1%甲酸钙极显著提高日增重 (P <0 .0 1)、仔猪采食量 (P <0 .0 5 ) ,显著降低仔猪断奶后腹泻频率 (P <0 .0 5 )、结肠Coliform总数 (P <0 .0 5 ) ;0 .2 %酸性蛋白酶显著提高 (P <0 .0 5 )饲料转化率、显著降低仔猪断奶后腹泻频率 (P <0 .0 5 )、结肠Coliform总数 (P <0 .0 5 ) ;两者在提高仔猪采食量 (P <0 .0 5 )上存在协同效应 ;酸性蛋白酶和甲酸钙降低商品猪生产成本 。

Zinc phosphate-based nanoparticles as a novel antibacterial agent: in vivo study on rats after dietary exposure

Background: Development of new nanomaterials that inhibit or kil bacteria is an important and timely research topic. For example, financial losses due to infectious diseases, such as diarrhea, are a major concern in livestock productions around the world. Antimicrobial nanoparticles(NPs) represent a promising alternative to antibiotics and may lower antibiotic use and consequently spread of antibiotic resistance traits among bacteria, including pathogens.Results: Four formulations of zinc nanoparticles(Zn A, Zn B, Zn C, and Zn D) based on phosphates with spherical(Zn A, Zn B)or irregular(Zn C, Zn D) morphology were prepared. The highest in vitro inhibitory effect of our NPs was observed against Staphylococcus aureus(inhibitory concentration values, IC50, ranged from 0.5 to 1.6 mmol/L), fol owed by Escherichia coli(IC500.8–1.5 mmol/L). In contrast, methicil in resistant S. aureus(IC501.2–4.7 mmol/L) was least affected and this was similar to inhibitory patterns of commercial Zn O-based NPs and Zn O. After the successful in vitro testing, the in vivo study with rats based on dietary supplementation with zinc NPs was conducted. Four groups of rats were treated by 2,000 mg Zn/kg diet of Zn A, Zn B, Zn C, and Zn D, for comparison two groups were supplemented by 2,000 mg Zn/kg diet of Zn O-N and Zn O, and one group(control) was fed only by basal diet. The significantly higher(P < 0.05) Zn level in liver and kidney of al treated groups was found, nevertheless Zn NPs did not greatly influence antioxidant status of rats. However,the total aerobic and coliform bacterial population in rat feces significantly decreased(P < 0.05) in al zinc groups after 30 d of the treatment. Furthermore, when compared to the Zn O group, Zn A and Zn C nanoparticles reduced coliforms significantly more(P < 0.05).Conclusions: Our results demonstrate that phosphate-based zinc nanoparticles have the potential to act as antibiotic agents.

Horizontal Distribution and Annual Variations of Fecal Coliform Bacteria in Luoyuan Bay

Fecal Coliform Bacteria （FCB） of marine waters was monitored in Luoyuan Bay from January, 2003 to December, 2005. The results showed that number of FCB in marine water samples ranged from no detection （ 〈2 cfu/100 mL） to 540 cfu/100 mL in Luoyuan Bay. Values of FCB during August to October were significantly higher than those during January to April during three year period. Monthly changes of FCB values at each year period were mainly due to monthly precipitation. In addition, compared with FCB values in difference sample sites, values of FCB in Bay-heed were significantly higher than those in middle of bay and Bay-mouth, Luoyuan Bay. However, values of FCB in Bay-mouth were significantly less than those in middle of bay. The ratios to the par of FCB in 2003, 2004, and 2005 years were 100%, 98.0%, and 97.9%, respectively. Therefore, we considered that the pollution of FCB of surface marine water in Luoyuan Bay was not serious.