Category Archives: Klebsiella

Research – Microbiological and physicochemical properties of farm bulk tank milk and antimicrobial resistance of its dominant bacteria

Wiley Online


This study determined the antibiotic resistance of the dominant bacteria in the 85 farm BTMs according to the guidelines recommended by the epidemiological cutoff values in the EUCAST. In addition, some physicochemical and microbiological properties of farm BTMs were investigated. The milk samples were divided into two groups according to their SCC values. The milk samples with higher SCC than 400,000 cells mL−1 were further examined bacteriologically, and the antibiotic resistance of isolates was determined. The average TAMB value was 6.34 log CFU/mL in farm BTM. It was found that high-SCC values did not affect other physicochemical properties of BTM samples, such as fat, protein and total solids, except for lactose content. Seventy-two strains were isolated from 45 bulk milk samples. The most prevalent bacteria were Enterococcus spp. (23.61%). The other isolates were Citrobacter spp. (12.5%), Staphylococcus spp. (12.51%), Serratia spp. (11.12%), Klebsiella spp. (9.72%), Bacillus spp. (9.72%), and Enterobacter spp. (8.33%). In antibiotic resistance analysis, 52.6% of Enterobacterales isolates showed cefoxitin resistance, and nine Enterobacterales isolates were determined as the presumptive ESBL producers. None of them was confirmed as ESBL producers. Moreover, MDR was detected in 83.3% of Enterobacter spp. isolates and all Bacillus spp. isolates. The over and inappropriate use of antibiotics in mastitis treatment may cause antibiotic-resistant microorganisms in milk. It was found that 52.7% of the isolated bacteria were MDR, which could pose a risk to public health and food safety, with the consumer’s increasing interest in consuming raw milk.

Research – Antibacterial activity of sweet orange (Citrus sinensis) juice extract on selected bacteria


Plants have potentials to be developed into many new drugs yet to be discovered because of the countless chemical compositions in them. The investigation is targeted at the antibacterial activity of sweet orange juice extract on some bacteria using ethanol and ethyl ethanoate solvent to extract juice. Ditch method was used for the sensitivity testing against Escherichia coliStaphylococcus aureusKlebsiella pneumoniae and Neisseria gonorrheae with a dilution factor of 10-10 for inoculation from pure culture of each selected bacteria. Disc method was used to test streptomycin, ciprofloxacin, gentamycin and penicillin G against test organisms as positive controls. There was no significant difference in the effect of different concentrations of the same extract on test organisms. However, there was a significant difference in the ethyl ethanoate and alcohol extracts. The ethyl ethanoate extract showed minimum inhibitory concentration at 300 mg/ml on E. coli (31.5 ± 0.5 mm); Ngonorrheae (21 ± 0.0 mm) at 200 mg/ml; Saureus (22 ± 0.0 mm) and Kpneumoniae (37 ± 3.0 mm) at 100 mg/ml; while ethanol extract at 100 mg/ml on E. coli (23.5 ± 1.5 mm) and Kpneumoniae (25 ± 5.0 mm);  N. gonorrheae (13.5 ± 1.0 mm) and S. aureus (12.5 ± 2.5 mm) at 300 mg/ml and 200 mg/ml respectively. The zones of inhibition exhibited by streptomycin ranges from Ngonorrheae (14-24 mm) E. coli; ciprofloxacin varies from 15- 21 mm on K. pneumoniae and S. aureus respectively. Gentamycin ranges from 14-20 mm on N. gonorrheae and S. aureus respectively; and penicillin G on N. gonorrheae (14 mm) and Saureus (28 mm). It can be concluded that sweet orange juice of ethyl ethanoate extract was more effective than the ethanol extract and the positive control.

Nigeria – Study Shows 76% Of Germs On Ready-To-Eat Fruits Are Multidrug-Resistant

Tribune Online

CONSUMPTION of fresh cut, ready-to-eat fruits (FCFs) processed and vended in open markets in Nigeria may constitute human health risks, causing food-borne diseases, due to microbial contamination, a study warns.

In the study, researchers had assessed pineapple and watermelon, which are among the commonest ready-to-eat fruits retailed and consumed regularly, including samples of fruit wash water and vendors’ hand, and found them heavily infested with different germs.

Research – Microbial Safety of Smoothie Drinks from Fresh Bars Collected in Slovakia


Among the many consumers in Slovakia, smoothies are nowadays gaining popularity. Smoothie drinks are prepared from raw fruits and vegetables. Therefore, their microbiological safety depends on hygiene standards. The aim of this work was to monitor and quantify selected sensitive and antibiotic-resistant microorganisms present in collected smoothies. Twenty analyzed smoothie samples were collected from six food service establishments (fresh bars) in the capital city of Slovakia, Bratislava. Antibiotic-resistant bacteria were found in at least one of each fresh bar. Antibiotic-resistant coliform bacteria prevailed, especially in green smoothies or juices containing more vegetable ingredients. Resistance to ampicillin, ciprofloxacin, tetracycline, chloramphenicol, and gentamicin was observed in the case of coliform bacteria. More than half of the smoothie drink samples did not contain resistant enterococci. On the other hand, vancomycin-resistant enterococci were detected in 20% of samples. The most frequently isolated antibiotic-resistant strains belonged to the Enterobacter spp. or Klebsiella spp. genus. In the last part of the work, the pretreatment effect of smoothie components on the selected microorganisms’ counts in the final product was investigated. Washing ingredients with an aqueous solution of a biocide agent containing silver and hydrogen peroxide proved to be the most effective way to decrease bacterial counts. View Full-Text

Research – Microbial analysis and factors associated with contamination of ready-to-eat chili pepper sauce in Buea municipality, Cameroon


Chili peppers sauce is a dietary complement largely consumed in Cameroon. It is consumed in a powder or wet (pepper sauce) form or directly introduced into cooked food. In this study, the microbiological quality of chili pepper sauce used as food complement in the Buea municipality was assessed. The study was an observational and cross-sectional study involving 70 chili pepper sauce samples from food vendors. The samples were cultured on Salmonella-Shigella agar, violet red bile agar, plate count agar and the colonies isolated were enumerated and identified using the Enterosystem 18R. Factors associated with microbial count were identified using a multiple linear regression model. Bacteria isolate from chili pepper sauce were mainly Entrobacter cloacae (31.57%), Citrobacter freundii (15.78%) and Klebsiella pneumonia (15.78%) and other Enterococcal speciesFactors associated with bacteria count were: age of the vendor, number of customers served, types of food and food storage conditions (covering, heating, type of storage containers). Chili pepper sauce used as food complement in Buea Municipality were contaminated with Enteric microorganisms and may represents a potential public health hazard to consumers. The presence of these microorganisms from chilli pepper sauce could result from poor handling.

Research – Survival and Histamine Production by Histamine-Forming Bacteria Exposed to Low Doses of Gamma Irradiation



Histamine poisoning occurs when fish containing high amount of histamine are consumed. Because histamine is thermally stable, control of histamine-forming bacteria in seafood is an appropriate strategy for preventing the formation of histamine. One prevention method is the use of gamma irradiation on the histamine formers. To understand the effect of gamma irradiation on the histamine-forming bacteria, laboratory isolates of the prolific histamine formers Morganella morganii, Klebsiella variicola, and Proteus vulgaris were exposed to various doses of gamma radiation in nutrient broth and tuna muscle spiked with histamine formers. None of the test bacteria survived in tuna muscle irradiated at 2.0 kGy. K. variicola was highly sensitive to gamma irradiation and was eliminated at a dose of 1.5 kGy. Histamine production also was reduced significantly as the radiation dose increased. These results suggest that gamma irradiation can effectively eliminate histamine-forming bacteria and reduce the threat of histamine poisoning from seafood.

  • Histamine-forming bacteria are highly susceptible to low levels of gamma irradiation.
  • Prolific histamine formers in tuna meat were eliminated by irradiation at 2.0 kGy.
  • Irradiation at 1.5 kGy reduced the level of histamine formers in tuna meat by 4 to 5 log CFU.
  • Histamine formation in tuna meat can be controlled by low levels of gamma irradiation.

Research – Foodborne Klebsiella pneumoniae: Virulence Potential, Antibiotic Resistance, and Risks to Food Safety


CDC Klebsiella

Image CDC


Gastrointestinal carriage of Klebsiella pneumoniae is a predisposing factor for liver abscess in several Asian countries. To determine whether hypervirulent K. pneumoniae in the gut may be transmitted through food, we screened a range of raw and ready-to-eat retail food by culture and recovered K. pneumoniae in 21% (147 of 698) of samples tested. Based on PCR, no K. pneumoniae isolates carried the rmpA gene linked to community-acquired pyogenic liver abscess, providing no evidence of a link between food and liver disease. However, phenotypic resistance to multiple antibiotic classes was seen through disk diffusion tests, and carriage of genetic elements (wcaG and capsule types K1, K2, and K54) associated with increased virulence (8%, 11 of 147) was observed by PCR. Multidrug-resistant isolates were from raw vegetables, chicken or pork liver, and a ready-to-eat poultry dish; one multidrug-resistant K. pneumoniae isolate from raw bean sprouts was resistant to a third-generation cephalosporin (ceftriaxone). Although K. pneumoniae may be present in food without causing harm, we found isolates belonging to the K1 capsular serotype coexisting with the wcaG gene, one also conferring multidrug resistance. K. pneumoniae that carry antibiotic resistance genes, regardless of pathogenicity, may increase the available genetic pool of resistance along the food chain. Hygienic food handling practices are necessary to lower risks of acquiring K. pneumoniae and other opportunistic pathogens.

Research – Inactivation modeling of microorganisms using organic chlorine and acetic acid solutions and estimation of growth kinetics of adhered Enterobacteriaceae to lettuce (Lactuca sativa L.)

Wiley Online

This study was aimed to evaluate the efficiency of the organic chlorine and acetic acid solutions on the inactivation of adhered cells of Escherichia coliCronobacter sakazakii and Klebsiella pneumoniae to lettuce. Besides, the growth and inactivation of K. pneumoniae adhered to lettuce was modeled. According to the findings, the use of chlorine solution (170 mg/ml of total residual chlorine) caused reductions of 1.8, 1.9, and 1.9 log for E. coliC. sakazakii, and K pneumoniae, respectively, were recorded. In this regard, the organic chloramine was more effective in controlling the adhered microorganisms while compared with 1.5% acetic acid solution, while the addition of 0.5% sodium chloride to 1.5% acetic acid solution increased microbial inactivation. K. pneumoniae RC‐34 inactivation was characterized by the presence of two sub‐populations with different resistances against the proposed sanitizers. Moreover, the growth kinetic parameters of K. pneumoniae RC‐34 adhered to lettuce leaves were very similar to that reported in the literature for nonadhered microorganisms. The predictive data generated can be valuable to assess the growth and inactivation of produce adhered microorganisms in leafy produce.

Research – Your energy-efficient washing machine could be harbouring pathogens

Science Daily 

For the first time ever, investigators have identified a washing machine as a reservoir of multidrug-resistant pathogens. The pathogens, a single clone of Klebsiella oxytoca, were transmitted repeatedly to newborns in a neonatal intensive care unit at a German children’s hospital. The transmission was stopped only when the washing machine was removed from the hospital. The research is published this week in Applied and Environmental Microbiology, a journal of the American Society for Microbiology.

Research – Effect of Sodium Hypochlorite on Biofilm-Forming Ability of Histamine-Producing Bacteria Isolated from Fish

Journal of Food Protection


Histamine poisoning occurs when temperature-abused marine fish containing elevated levels of histamine are consumed. Histamine-producing bacteria found in fish can colonize processing surfaces and form biofilms. In this study, the biofilm-forming abilities of histamine-producing bacteria from Indian mackerel (Rastrelliger kanagurta) and the effect of hypochlorite treatment on biofilm formation were studied. The isolates of this study produced histamine in the range of 471 to 2,126 ppm. The histidine decarboxylase gene hdc was detected in all isolates producing histamine except in one strain each of Psychrobacter pulmonis and Proteus vulgaris. All isolates tested in this study produced moderate biofilms under control conditions, whereas exposure to 1 and 3 ppm of sodium hypochlorite significantly enhanced biofilm formation. However, exposure to 5 ppm of sodium hypochlorite showed an inhibitory effect on biofilm formation by all the isolates except Klebsiella variicola. The results of this study suggest that histamine-producing bacteria can form stable biofilms and that this activity may be enhanced by the application of low levels of sodium hypochlorite, a phenomenon that might influence the persistence of histamine-producing bacteria in fish processing areas.

  • Bacteria isolated from Indian mackerel produced histamine in the range of 471 to 2,126 ppm.

  • Histamine-producing bacteria isolated from the same fish can vary in the levels of histamine produced.

  • The hdc gene was not detected in one strain each of Psychrobacter pulmonis and Proteus vulgaris.

  • All histamine-producing bacteria formed moderate biofilms under control conditions.

  • Exposure to 1 and 3 ppm of sodium hypochlorite increased biofilm formation by histamine-producing bacteria.