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This work aimed to determine potential sites of contamination and transmission of SARS-CoV-2 during the COVID-19 pandemic in a public hospital in Culiacan, Sinaloa, México. The sampling was carried out from February to April 2022 of surfaces in the COVID areas and the Intensive Care Unit (ICU) of one public hospital in Culiacan, Sinaloa, Mexico. Samples were taken using a sterile sponge moistened with phosphate buffer. RNA extraction was performed with the Viral RNA mini kit (Qiagen), and the detection was performed with the CDC 2019-Novel Coronavirus kit. During the surveillance period in the public hospital, 11 samples were taken from surfaces. SARS-CoV-2 was found in 63.6 % of the samples. SARS-CoV-2 was absent from the ICUs; however, it was recovered in the COVID area of the public hospital (n = 7). The COVID area was the main point of contamination during the pandemic. On the other hand, it is notable that the virus was not detected outside this area, which can be associated with the adequate hospital containment measures adopted during the health emergency. [ABSTRACT FROM AUTHOR]

In this study, packinghouses spraying disinfection process was simulated to compare the effectiveness of aqueous chlorine dioxide and sodium hypochlorite in reducing Escherichia coli O157:H7 on bell pepper surface. Bell peppers inoculated with 7.74 Log10 CFU of E. coli O157:H7 were placed in a rotary mixer (60 rpm), and sprayed with chlorine dioxide and sodium hypochlorite. Chlorine dioxide at 5 mg L-1 during 20-30 s reduces from 7.74 Log10 CFU of E. coli O157:H7 adhered on bell pepper to undetectable numbers, while the exposition with chlorine dioxide at pH 6 and 8 during 10 s was necessary to reduce 4.25 and 3.90 Log10 CFU, respectively. On the other hand, sodium hypochlorite at 200 mg L-1 at pH 6 reduced 2.89, 3.25 and 3.54 Log10 CFU/bell pepper at 10, 20 and 30 s, respectively. Spraying disinfection process using aqueous chlorine dioxide was more effective than sodium hypochlorite applications, therefor chlorine dioxide is an effective alternative to reduce E. coli O157:H7 on bell pepper surface. [ABSTRACT FROM AUTHOR]

Shiga toxin-producing Escherichia coli (STEC) are zoonotic enteric pathogens associated with human gastroenteritis worldwide. Cattle and small ruminants are important animal reservoirs of STEC. The present study investigated animal reservoirs for STEC in small rural farms in the Culiacan Valley, an important agricultural region located in Northwest Mexico. A total of 240 fecal samples from domestic animals were collected from five sampling sites in the Culiacan Valley and were subjected to an enrichment protocol followed by either direct plating or immunomagnetic separation before plating on selective media. Serotype O157:H7 isolates with the virulence genes stx2, eae, and ehxA were identified in 40% (26/65) of the recovered isolates from cattle, sheep and chicken feces. Pulse-field gel electrophoresis (PFGE) analysis grouped most O157:H7 isolates into two clusters with 98.6% homology. The use of multiple-locus variable-number tandem repeat analysis (MLVA) differentiated isolates that were indistinguishable by PFGE. Analysis of the allelic diversity of MLVA loci suggested that the O157:H7 isolates from this region were highly related. In contrast to O157:H7 isolates, a greater genotypic diversity was observed in the non-O157 isolates, resulting in 23 PFGE types and 14 MLVA types. The relevant non-O157 serotypes O8:H19, O75:H8, O111:H8 and O146:H21 represented 35.4% (23/65) of the recovered isolates. In particular, 18.5% (12/65) of all the isolates were serotype O75:H8, which was the most variable serotype by both PFGE and MLVA. The non-O157 isolates were predominantly recovered from sheep and were identified to harbor either one or two stx genes. Most non-O157 isolates were ehxA-positive (86.5%, 32/37) but only 10.8% (4/37) harbored eae. These findings indicate that zoonotic STEC with genotypes associated with human illness are present in animals on small farms within rural communities in the Culiacan Valley and emphasize the need for the development of control measures to decrease risks associated with zoonotic STEC. [ABSTRACT FROM AUTHOR]

Irrigation water can serve as a vehicle for transporting pathogenic microorganisms, and numerous cases of bacterial infections from consumption of irrigated fresh produce have been reported in recent years. Chlorine-based disinfectants applied when produce is packed are widely used to control microorganisms. When applied properly, the chlorine products are effective. However, hazardous disinfection breakdown products can be formed, and chlorine disinfectants have high oxidant activity that can affect produce quality and pose a risk to food handlers. Quaternary Ammonium Compounds (QACs) are a disinfectant alternative for the washing of fruits and vegetables. They can control a great number of microorganisms, have low toxicity when used at recommended doses, and are stable in storage. The purpose of this work was to assess the disinfectant activity of QACs against Escherichia coli and Staphylococcus aureus under worst-case and average-case turbidity conditions, (2 and 100 nephelometric units); two disinfectant concentrations (100 and 200 mg/L; and two contact times (30 and 120 seconds). Our research showed that QACs were effective against both bacteria. The percentage reduction of Escherichia coli was significantly higher in the less turbid solution (P = 0.027), while turbidity did not affect the reduction of Staphylococcus aureus (P> 0.05). E. coli was more resistant to QAC treatment than S. aureus. Based on the data obtained we can conclude that QACs could be an alternative in washing processes of fruits and vegetables. [ABSTRACT FROM AUTHOR]

The purpose of this study was to compare chlorinated and ozonated water in reducing Salmonella typhimurium inoculated onto fresh ripe tomatoes. Surface-inoculated tomatoes were immersed/sprayed with chlorinated (200 mg l(-1)) and ozonated water (1 and 2 mg l(-1)) under 2 and 100 nefelometric turbidity units (NTU). Contact times were 120 and 30 s for immersing and spraying applications, respectively. Immersing in chlorinated water and low turbidity resulted in the most effective application with 3.61 log(10) bacterial reduction, while 1 and 2 mg l(-1) of ozone reduced 2.32 and 2.53 log(10), respectively. High turbidity and chlorine reduced the bacterial counts by 3.39 log(10), while 1 and 2 mg l(-1) of ozonated water and low turbidity reduced the bacteria by 1.48 and 1.92 log(10), respectively. Spraying chlorinated water reduced bacteria by 3 log(10), and ozonated water at 1 and 2 mg l(-1) reduced counts by 1.84 and 2.40 log(10), respectively. No statistical differences were found between chlorine and ozone (2 mg l(-1)) during spraying applications (p < 0.05). The use of ozonated water both in immersing and spraying applications is suggested when water turbidity remains low.