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PloS One 2022Coliform bacteria are major causative agents of bovine mastitis, a disease that has devastating effect on dairy animal health and milk production. This cross-sectional...
BACKGROUND
Coliform bacteria are major causative agents of bovine mastitis, a disease that has devastating effect on dairy animal health and milk production. This cross-sectional study, carried out in the North West region of Cameroon, sought to determine the prevalence of bovine mastitis, coliforms associated with bovine mastitis, risk factors for infection and the antibiotic resistance pattern of coliform bacterial isolates.
MATERIALS AND METHODS
A total of 1608 udder quarters were sampled from 411 cows using a questionnaire, clinical examination, California Mastitis Test and milk culture. Primary isolation of coliform bacteria was done on MacConkey agar while identification of coliforms employed Gram-staining and biochemical testing. Each coliform bacterial isolate was challenged with 11 antibiotics using the Kirby-Bauer disc diffusion method.
RESULTS
The prevalence of mastitis was 53.0% (218/411) and 33.1% (532/1608) at the cow- and quarter-levels respectively. Overall, 21.9% (90/411) cows and 8.2% (132/1608) udder quarters showed coliform mastitis. Escherichia coli was isolated in 7.0% of mastitis milk, and other coliforms isolated were Enterobacter cloacae (12.6%), Klebsiella pneumoniae (2.4%), Enterobacter sakazakii (1.1%), Klebsiella oxytoca (0.8%), Citrobacter freudii (0.4%), Serratia ficaria (0.4%) and Serratia liquefaciens (0.2%). Lactation stage, breed, history of mastitis and moist/muddy faeces contaminated environment were significantly associated (P-value < 0.05) with coliform mastitis. Coliform isolates (99.0%; 203/205) were resistant to at least one antibiotic tested. Amoxicillin had the highest resistance (88.8%) while norfloxacin had the least resistance (3.4%). Multidrug resistance was exhibited by 52.7% (108/205) of the isolates in a proportion of 27.8% Enterobacter cloacae, 10.7% E. coli, 6.3% Klebsiella pneumoniae, 2.9% Enterobacter sakazakii, 2.0% Klebsiella oxytoca, 1.0% Citrobacter freundii, 1.0% Serratia ficaria, 0.5% Serratia liquefaciens and 0.5% Serratia odorifera.
CONCLUSION
Results indicate a need to educate these dairy farmers about mastitis (particularly subclinical), proper hygiene methods in milking and the public health implications of consuming contaminated raw milk.
Topics: Animals; Anti-Bacterial Agents; Cameroon; Cattle; Cross-Sectional Studies; Drug Resistance, Microbial; Escherichia coli; Female; Humans; Klebsiella pneumoniae; Lactation; Mastitis, Bovine; Milk; Prevalence; Risk Factors; Serratia
PubMed: 35881624
DOI: 10.1371/journal.pone.0268247 -
Environmental Science and Pollution... May 2022The inactivation processes of coliform bacteria (total and fecal) and sulphito-reducing Clostridium bacteria (vegetative species and spores) in water maturation lagoon...
The inactivation processes of coliform bacteria (total and fecal) and sulphito-reducing Clostridium bacteria (vegetative species and spores) in water maturation lagoon of a low-cost nature-based wastewater treatment plant using constructed wetlands and through processes of photolysis in a pilot photoreactor have been comparatively studied. The different inactivation mechanisms by photolysis of these bacteria have been studied following the criteria of different statistical and kinetic models. Clostridium disinfection treatments fit models in which two types of bacteria populations coexist, one sensitive (vegetative species) and the other (spores) resistant to the treatment, the sensitive one (94%) with an inactivation rate of k = 0.24 ± 0.07 min and the resistant one (6%) with k = 0.11 ± 0.05 min. Total coliform photolytic disinfection also shows two populations with different physiological state. The time required to reduce the first logarithmic decimal cycle of the different types of bacteria (physiological states) are δ = 4.2 ± 0.9 and δ = 8.3 ± 1.1 min, respectively. For fecal coliform photolytic disinfection, only bacteria population, with k = 1.15 ± 0.19 min, is found. The results obtained confirm the photolytic disinfection processes and maturation lagoon are effective systems for Clostridia bacteria removal after water treatment by nature-based systems. Total removal of coliform bacteria is not achieved by maturation lagoons, but their reduction is significant using low doses of cumulative radiation.
Topics: Bacteria; Clostridium; Disinfection; Photolysis; Ultraviolet Rays; Wastewater; Water Purification
PubMed: 35060052
DOI: 10.1007/s11356-021-18184-w -
Journal of Dairy Science Jan 2018Fluid milk quality in the United States has improved steadily over the last 2 decades, in large part due to the reduction in post-pasteurization contamination (PPC).... (Review)
Review
Fluid milk quality in the United States has improved steadily over the last 2 decades, in large part due to the reduction in post-pasteurization contamination (PPC). Despite these improvements, some studies suggest that almost 50% of fluid milk still shows evidence of PPC with organisms that are able to grow at 6°C, even though PPC may be much less frequent in some facilities. Several gram-negative bacteria, when introduced as PPC, can grow rapidly at refrigeration temperatures around 6°C and can lead to bacterial levels above 20,000 cfu/mL (the regulatory limit for bacterial numbers in fluid milk in the United States) and spoilage that can be detected sensorially within 7 to 10 d of processing. Importantly, however, storage temperature can have a considerable effect on microbial growth, and fluid milk stored at 4°C and below may show considerably delayed onset of microbial growth and spoilage compared with samples stored at what may be considered mild abuse (6°C and above). Notable organisms that cause PPC and grow at refrigeration temperatures include psychrotolerant Enterobacteriaceae and coliforms, as well as Pseudomonas. These organisms are known to produce a variety of enzymes that lead to flavor, odor, and body defects that can ultimately affect consumer perception and willingness to buy. Detecting PPC in high temperature, short time, freshly pasteurized fluid milk can be challenging because PPC often occurs sporadically and at low levels. Additionally, indicator organisms typically used in fluid milk (i.e., coliforms) have been shown to represent only a fraction of the total PPC. Recent studies indicate that coliforms account for less than 20% of the total gram-negative organisms introduced into fluid milk after pasteurization. In contrast, Pseudomonas, which is not a coliform and therefore is not detected using coliform media, is the most commonly isolated genus in PPC fluid milk. To reduce PPC, processors must (1) use testing methods that can detect both coliforms and non-coliform gram-negatives (i.e., Pseudomonas) to understand true contamination rates and patterns, and (2) establish cleaning and sanitation protocols and employee and management behaviors that target persistent and transient PPC organisms.
Topics: Animals; Bacteria; Cattle; Food Contamination; Humans; Milk; Pasteurization; Quality Control; Taste
PubMed: 29103726
DOI: 10.3168/jds.2017-13339 -
Survival and detection of coliforms, Enterobacteriaceae, and gram-negative bacteria in Greek yogurt.Journal of Dairy Science Feb 2017Despite the widespread use of coliforms as indicator bacteria, increasing evidence suggests that the Enterobacteriaceae (EB) and total gram-negative groups more...
Despite the widespread use of coliforms as indicator bacteria, increasing evidence suggests that the Enterobacteriaceae (EB) and total gram-negative groups more accurately reflect the hygienic status of high-temperature, short-time pasteurized milk and processing environments. If introduced into milk as postpasteurization contamination, these bacteria may grow to high levels and produce a wide range of sensory-related defects. However, limited information is available on the use and survival of bacterial hygiene indicators in dairy products outside of pasteurized fluid milk and cheese. The goal of this study was to (1) provide information on the survival of a diverse set of bacterial hygiene indicators in the low pH environment of Greek yogurt, (2) compare traditional and alternative detection methods for their ability to detect bacterial hygiene indicators in Greek yogurt, and (3) offer insight into optimal hygiene indicator groups for use in low-pH fermented dairy products. To this end, we screened 64 bacterial isolates, representing 24 dairy-relevant genera, for survival and detection in Greek yogurt using 5 testing methods. Before testing, isolates were inoculated into plain, 0% fat Greek yogurt (pH 4.35 to 4.65), followed by a 12-h hold period at 4 ± 1°C. Yogurts were subsequently tested using Coliform Petrifilm (3M, St. Paul, MN) to detect coliforms; Enterobacteriaceae Petrifilm (3M), violet red bile glucose agar and the D-Count (bioMérieux, Marcy-l'Étoile, France) to detect EB; and crystal violet tetrazolium agar (CVTA) to detect total gram-negative bacteria. Overall, the non-EB gram-negative isolates showed significantly larger log reductions 12 h after inoculation into Greek yogurt (based on bacterial numbers recovered on CVTA) compared with the coliform and noncoliform EB isolates tested. The methods evaluated varied in their ability to detect different microbial hygiene indicators in Greek yogurt. Crystal violet tetrazolium agar detected the highest portion of coliforms, whereas EB Petrifilm detected the highest portion of EB, as well as highest portion of total gram-negative bacteria. Additionally, the D-Count method allowed for faster detection of EB in yogurt by generating results in approximately 13 h rather than the 24 h required when using EB Petrifilm and violet red bile glucose agar. Results from this study indicate that the coliform and EB groups encompass a broad range of dairy-relevant gram-negative bacteria with the ability to survive in Greek yogurt, supporting their use as microbial hygiene indicator groups in low-pH fermented dairy products.
Topics: Animals; Colony Count, Microbial; Enterobacteriaceae; Food Microbiology; Greece; Milk; Yogurt
PubMed: 27988132
DOI: 10.3168/jds.2016-11553 -
Annals of Agricultural and... Jun 2022The aim of the study was to determine the presence and concentration of indicator microorganisms on leafy green vegetables available in Poland.
OBJECTIVE
The aim of the study was to determine the presence and concentration of indicator microorganisms on leafy green vegetables available in Poland.
MATERIAL AND METHODS
Microbial analyses of 122 samples of leafy green vegetables: rocket, lamb's lettuce, iceberg lettuce, chive, spinach, celery, dill and parsley, sold in Polish supermarkets in 2018 and 2019, were conducted. The vegetables were analyzed for aerobic mesophilic bacteria, yeasts and moulds, , coliforms and number according to Polish standards.
RESULTS
The most microbiologically contaminated vegetables occurred to be parsley, rocket and spinach, and the least contaminated was iceberg lettuce. The presence of total mesophilic bacteria was found in all samples. The highest average number of mesophilic bacteria was found for lamb's lettuce, rocket, parsley and spinach. Numerous yeasts were presented in almost all leafy green samples while rocket and parsley were the most contaminated with moulds. were isolated from all samples of parsley. High populations of these bacteria were found in rocket and celery samples. Of the 122 vegetable samples, 95 (78%) were positive for coliforms, especially all samples of parsley were inhabited by these bacteria. 24% of all samples were contaminated by , mainly parsley, spinach and chive. The presence of was found in only one sample of spinach.
CONCLUSIONS
The levels of aerobic mesophilic bacteria, yeasts and moulds, and coliforms in leafy green vegetables sold in Poland could be classified as moderate or low. The abundant presence of the studied microorganisms may pose a risk for some categories of people consuming leafy green vegetables, mostly immuno-compromised persons.
Topics: Bacteria; Colony Count, Microbial; Enterobacteriaceae; Escherichia coli; Food Contamination; Food Microbiology; Fungi; Vegetables
PubMed: 35767757
DOI: 10.26444/aaem/149963 -
Journal of Food Protection Apr 2022Following removal of hides and viscera during beef processing, carcasses are inspected for tissue adhesions that can affect meat quality or harbor bacteria. Carcasses...
ABSTRACT
Following removal of hides and viscera during beef processing, carcasses are inspected for tissue adhesions that can affect meat quality or harbor bacteria. Carcasses with pleural or abdominal adhesions may be diverted from the production line for manual excision and then returned to the line. No published data indicate whether adhesion excision is associated with bacterial contamination. Therefore, our objective was to determine the presence and concentration of generic Escherichia coli and non-E. coli coliforms from the internal and external surfaces of carcasses that were, or were not, diverted for adhesion excision. During 9 processing days over a 4-month period in a large commercial beef processing facility, 1,738 carcass sponge samples from 2,730 cm2 areas on both the internal and the external surfaces of carcasses with and without tissue adhesions were collected. Coliforms and E. coli were cultured and enumerated using Petrifilm procedures, and data were analyzed with mixed models. Coliforms were present at higher concentrations than E. coli, and prevalence and mean log concentrations of both coliforms and E. coli were significantly higher for samples from the external than from the internal surfaces of carcasses. However, differences in prevalence and concentration of coliforms between external and internal surfaces varied significantly based on whether carcasses had adhesions excised. The difference was greatest for coliforms present on the external (2.06 log CFU/100 cm2) versus the internal (0.93 log CFU/100 cm2) carcass surfaces without adhesions, whereas the difference in concentrations from the external (1.80 log CFU/100 cm2) and the internal (1.31 log CFU/100 cm2) surfaces of carcasses with adhesions was not as large. These results indicate that surveillance of carcass bacteria may be affected by whether the external versus the internal surfaces are sampled and whether carcasses are diverted for excision of adhesions.
Topics: Abattoirs; Animals; Bacteria; Cattle; Colony Count, Microbial; Escherichia coli; Food Contamination; Food Handling; Food Microbiology; Meat; Tissue Adhesions
PubMed: 35076692
DOI: 10.4315/JFP-21-426 -
Journal of Microorganism Control 2023Shredded cabbage treated with either tap water or electrolyzed water was stored in an active modified atmosphere packaging (MAP) of 10% CO for 5 d at 10℃, 7 d at 5℃,...
Shredded cabbage treated with either tap water or electrolyzed water was stored in an active modified atmosphere packaging (MAP) of 10% CO for 5 d at 10℃, 7 d at 5℃, and 8 d at 1℃ to evaluate the occurrence and viability of sublethally injured coliform bacteria. The CO and O concentrations in the packages approached an equilibrium of 10% CO and 10% O during storage at all temperatures tested. Coliforms in shredded cabbage increased during storage at all three temperatures, with the increase being greater at 10℃. Sublethal injury at 65% to 69% for the coliforms was detected only on cabbage samples treated with electrolyzed water and stored at 5℃ for 4 and 7 d. Enterobacter cloacae was one of the injured species of coliform bacteria in shredded cabbage. Shredded cabbage was inoculated with chlorine-injured Escherichia coli O157:H7 and stored at 5℃ for 6 d in an active MAP of 10% CO. Counts of E. coli O157:H7 remained almost constant during storage, and injured E. coli O157:H7 ranging from 50% to 70% were found on shredded cabbage throughout the storage period. These results indicate that sublethally injured indicator and pathogenic bacteria would be found on fresh-cut cabbage in the realistic MAP storage at 5℃.
Topics: Brassica; Carbon Dioxide; Food Microbiology; Colony Count, Microbial; Escherichia coli; Food Packaging; Water
PubMed: 37866892
DOI: 10.4265/jmc.28.3_109 -
PloS One 2014Current guidelines recommend the use of Escherichia coli (EC) or thermotolerant ("fecal") coliforms (FC) as indicators of fecal contamination in drinking water. Despite... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Current guidelines recommend the use of Escherichia coli (EC) or thermotolerant ("fecal") coliforms (FC) as indicators of fecal contamination in drinking water. Despite their broad use as measures of water quality, there remains limited evidence for an association between EC or FC and diarrheal illness: a previous review found no evidence for a link between diarrhea and these indicators in household drinking water.
OBJECTIVES
We conducted a systematic review and meta-analysis to update the results of the previous review with newly available evidence, to explore differences between EC and FC indicators, and to assess the quality of available evidence.
METHODS
We searched major databases using broad terms for household water quality and diarrhea. We extracted study characteristics and relative risks (RR) from relevant studies. We pooled RRs using random effects models with inverse variance weighting, and used standard methods to evaluate heterogeneity and publication bias.
RESULTS
We identified 20 relevant studies; 14 studies provided extractable results for meta-analysis. When combining all studies, we found no association between EC or FC and diarrhea (RR 1.26 [95% CI: 0.98, 1.63]). When analyzing EC and FC separately, we found evidence for an association between diarrhea and EC (RR: 1.54 [95% CI: 1.37, 1.74]) but not FC (RR: 1.07 [95% CI: 0.79, 1.45]). Across all studies, we identified several elements of study design and reporting (e.g., timing of outcome and exposure measurement, accounting for correlated outcomes) that could be improved upon in future studies that evaluate the association between drinking water contamination and health.
CONCLUSIONS
Our findings, based on a review of the published literature, suggest that these two coliform groups have different associations with diarrhea in household drinking water. Our results support the use of EC as a fecal indicator in household drinking water.
Topics: Diarrhea; Drinking Water; Enterobacteriaceae; Escherichia coli; Family Characteristics; Feces; Humans; Reproducibility of Results; Risk Assessment; Risk Factors; Water Quality
PubMed: 25250662
DOI: 10.1371/journal.pone.0107429 -
Journal of Food Protection Oct 2016Chemical sanitizers may induce no injury (bacteria survive), sublethal injury (bacteria are injured), or lethal injury (bacteria die). The proportion of coliform...
Chemical sanitizers may induce no injury (bacteria survive), sublethal injury (bacteria are injured), or lethal injury (bacteria die). The proportion of coliform bacteria that were injured sublethally by chlorine and fungicide mixed with agricultural water (pond water), which was used to dilute the pesticide solution, was evaluated using the thin agar layer (TAL) method. In pure cultures of Enterobacter cloacae , Escherichia coli , and E. coli O157:H7 (representing a human pathogen), the percentage of chlorine-injured cells was 69 to 77% for dilute electrolyzed water containing an available chlorine level of 2 ppm. When agricultural water was mixed with electrolyzed water, the percentage of injured coliforms in agricultural water was 75%. The isolation and identification of bacteria on TAL and selective media suggested that the chlorine stress caused injury to Enterobacter kobei . Of the four fungicide products tested, diluted to their recommended concentrations, Topsin-M, Sumilex, and Oxirane caused injury to coliform bacteria in pure cultures and in agricultural water following their mixture with each pesticide, whereas Streptomycin did not induce any injury to the bacteria. The percentage of injury was 45 to 97% for Topsin-M, 80 to 87% for Sumilex, and 50 to 97% for Oxirane. A comparison of the coliforms isolated from the pesticide solutions and then grown on either TAL or selective media indicated the possibility of fungicide-injured Rahnella aquatilis , Yersinia mollaretii , and E. coli . These results suggest the importance of selecting a suitable sanitizer and the necessity of adjusting the sanitizer concentration to a level that will kill the coliforms rather than cause sanitizer-induced cell injury that can result in the recovery of the coliforms.
Topics: Chlorine; Colony Count, Microbial; Disinfectants; Escherichia coli O157; Humans; Water
PubMed: 28221856
DOI: 10.4315/0362-028X.JFP-16-124 -
International Journal of Environmental... Oct 2010Water is essential to life, but many people do not have access to clean and safe drinking water and many die of waterborne bacterial infections. In this review a general... (Review)
Review
Water is essential to life, but many people do not have access to clean and safe drinking water and many die of waterborne bacterial infections. In this review a general characterization of the most important bacterial diseases transmitted through water-cholera, typhoid fever and bacillary dysentery-is presented, focusing on the biology and ecology of the causal agents and on the diseases' characteristics and their life cycles in the environment. The importance of pathogenic Escherichia coli strains and emerging pathogens in drinking water-transmitted diseases is also briefly discussed. Microbiological water analysis is mainly based on the concept of fecal indicator bacteria. The main bacteria present in human and animal feces (focusing on their behavior in their hosts and in the environment) and the most important fecal indicator bacteria are presented and discussed (focusing on the advantages and limitations of their use as markers). Important sources of bacterial fecal pollution of environmental waters are also briefly indicated. In the last topic it is discussed which indicators of fecal pollution should be used in current drinking water microbiological analysis. It was concluded that safe drinking water for all is one of the major challenges of the 21st century and that microbiological control of drinking water should be the norm everywhere. Routine basic microbiological analysis of drinking water should be carried out by assaying the presence of Escherichia coli by culture methods. Whenever financial resources are available, fecal coliform determinations should be complemented with the quantification of enterococci. More studies are needed in order to check if ammonia is reliable for a preliminary screening for emergency fecal pollution outbreaks. Financial resources should be devoted to a better understanding of the ecology and behavior of human and animal fecal bacteria in environmental waters.
Topics: Bacteria; Humans; Water Microbiology; Water Supply
PubMed: 21139855
DOI: 10.3390/ijerph7103657