ACUTE BOVINE MASTITIS CAUSED BY KLEBSIELLA PNEUMONIAE – CASE REPORT

Th is case report describes the acute mastitis with signs of endotox-emia in the 32-month-old Simmental cow, antimicrobial susceptibility of Klebsiella pneumoniae isolated from a milk sample, and demonstrates the eff ectiveness of the applied therapy. Case presentation included the cow-lying syndrome together with the presence of clinical signs of endotoxemia accompanied by milk discoloration and “clots” formation. Bacteriology fi nding of the K. pneumoniae and antibiogram pointed that the isolate was sensitive to ceft riaxone, and trimethoprim/ sulfamethoxazole, while resistant to amoxicillin, gentamicin, ampicillin, ceft iofur, and cephalexin. Th e selection of treatment options came from the availability of an adequate route of administration, urgency for treatment, and lack of time for assessment of other body functions. Th e therapy by ceft riaxone at an intravenous dose rate of 8mg/kg with adequate supportive therapy NSAID, vitamin C, and correction dehydration showed a successful eff ect in life-saving procedures. Th e outcome of K. pneumoniae mastitis with endotoxemia did not aff ect the outcome of pregnancy


CASE PRESENTATION
Forty percent of all clinical mastitis are caused by coliform bacteria E. coli, Klebsiella spp., Enterobacter spp. (Schukken et al., 2012) with signifi cant losses in milk production and a high economic cost of treatment (Munoz et al., 2007). Th e primary source of K. pneumoniae in dairy farms was faecal discharges, as well as the presence of organic materials, such as wheat straw, barley straw, sand, and wood (Munoz et al., 2006), while the environmental factors, unhygienic conditions, and organic bedding are associated with the appearance of mastitis (Ngu Ngwa et al., 2018), where the opportunistic pathogens like K. pneumoniae additionally grow on organic and inorganic bedding materials (Zdanowicz et al., 2004). A 32-month-old pregnant Simmental cow with a daily milk yield of 25 kg (before the onset of mastitis) milking thrice per day, two months pregnant (pregnancy was confi rmed by ultrasound a couple of days before mastitis onset) was presented with swollen, painful, and stiff udder. Th e California mastitis test (CMT) score was (+++), i.e., a severe reaction to the CMT. Th e milk was a watery grey colour with clots. Th e cow had a rectal temperature of 39.6°C and displayed the lying-cow syndrome, similar to milk fever with preserved ruminal contraction. Th e daily milk yield drop was drastic, to only 1kg per 24 h. Diagnosis of mastitis was based on general clinical examination, physical examination of the udder, physical changes in the milk, the California mastitis test (CMT) score, and later fi ndings of microbiological analysis of the milk. Hematological and biochemical blood analyses were also performed. Each mammary gland quarter sample was collected aseptically and transported to the laboratory under refrigeration (4-8°C).
Aft er collection, the samples were placed in ice-cooled hand freezers and transported to the laboratory within 4 hours. Th e microbiology examination was conducted on routine methods (Markey et al., 2013). In brief: the milk samples were put on Columbia blood agar, MacConkey agar, and Sabouraud dextrose agar (all Torlak, Serbia) and kept at 37°C under aerobic conditions for 24 h, while Sabouraud agar was reincubated under aerobic conditions at 25°C up to 72 h. Th e primary isolate was stained by Gram procedure (Biomereux, France), followed by catalase and oxidase reaction (HiMedia, India). Presumptive diagnosis based on growth characteristics and said reactions were subjected to further biochemical testing using b commercial kits for enteric nonfermenter bacteria (BBL Crystal, E/N, ID kit, Becton, Dickinson and company, USA). Th ere was no growth on Sabouraud dextrose agar.

DISCUSSION
A bacteriology test with antibiogram revealed K. pneumoniae mastitis in one quarter with two antimicrobial options: ceft riaxone and trimethoprim/ sulfamethoxazole. Th e treatment option was infl uenced by the availability of an adequate route of administration, treatment urgency requirement, confi rmed pregnancy, and lack of time for assessment of other parameters (such are renal function, hypoglycaemia, or folate defi ciency) on the animal with presumptive endotoxemia. Th e therapy by ceft riaxone at an intravenous dose rate of 8mg/ kg with adequate supportive therapy NSAID, vitamin C, and body fl uid status correction was started immediately. Th e clinical appearance of the udder with systemic health deterioration with the eff ects of endotoxemia indicated the appearance of coliform mastitis. Previous records showed a couple of Escherichia coli mastitis isolates on the farm, all susceptible to ceft riaxone. In addition to the presence of cow-lying syndrome, the biochemical analysis of blood showed that calcium and magnesium were at the limit values of 2.2 mmo/L and 0.9 mmol/L, respectively. Th e cow was treated with ceft riaxone daily during fi ve days, and supportively with a large volume of Hartman's solution (100ml/kg body weight per 24h), glucose 10% (1000 ml per 24h), fl unixin meglumine (2.2 mg/kg b.wt intravenously once daily during fi ve days) and vitamin C (4 mg/kg b.wt intravenously once daily during three days). Th ree days aft er treatment, the CMT reaction showed only mild reaction to CMT. Five days aft er therapy, the CMT reaction was negative, and no clinical signs were present.
Th e previous history of mastitis in the herd was unrelated to the incidence of K. pneumoniae. Th e set of new wheat straw as bedding material a few days before the onset of mastitis was a potential way of introducing K. pneumoniae to the farm, adequate to previous fi ndings that the presence of organic matter as bedding may be the cause of mastitis (Munoz et al., 2006).
Th e antimicrobial susceptibility of this bacteria varies between diff erent studies due to a large number of strains (Osman et al., 2014). Th e present case showed the antibiogram to be sensitive to ceft riaxone and trimethoprim/ sulfamethoxazole; however, other studies (Enferad and Mahdavi, 2021) established that most strains of K. pneumoniae were 75% and 55% resistant to ceftriaxone and oxytetracycline, respectively. Th e duration of treatment (5 days) and persistence of clinical signs in our case followed previously reported study (Hoe and Ruegg, 2005). Supportive treatment of fl uids and electrolytes using NSAID (fl unixin meglumine) reduced the clinical signs of endotoxemia and accelerated recovery. We consider supportive therapy with vitamin C to reduce the duration of mastitis because ascorbic acid aff ects the recovery aft er clini-cal mastitis (Naresh et al., 2002). Aft er 15 days from the completed treatment, daily milk production had increased to 20 L; at the same point, pregnancy control was performed and reperformed two months aft er treatment, confi rming pregnancy while assuring the success of the applied therapy.
In the present case, ceft riaxone administration was justifi ed because of the narrowed choice of eff ective antibiotics available. Aft er 15 days, the cow regained 80% of its daily milk production. We conclude that correction of dehydration, executive elimination of K. pneumoniae systemic endotoxins, and ceft riaxone as the antibiotic of choice based on the antibiogram, assisted by vitamin C supportive therapy, resulted in a quick recovery. Th e outcome of mastitis in this cow or treatment option did not aff ect the pregnancy outcome. Educating the farmers about the potential source of infection is essential to prevent new episodes of mastitis.