Detection of Salmonella spp. with the BACTEC 9240 Automated Blood Culture System in 2008 - 2014 in Southern Iran (Shiraz): Biogrouping, MIC, and Antimicrobial Susceptibility Profiles of Isolates.
BACKGROUND
Human salmonellosis continues to be a major international problem, in terms of both morbidity and economic losses. The antibiotic resistance of Salmonella is an increasing public health emergency, since infections from resistant bacteria are more difficult and costly to treat.


OBJECTIVE
The aims of the present study were to investigate the isolation of Salmonella spp. with the BACTEC automated system from blood samples during 2008 - 2014 in southern Iran (Shiraz). Detection of subspecies, biogrouping, and antimicrobial susceptibility testing by the disc diffusion and agar dilution methods were performed.


METHODS
A total of 19 Salmonella spp. were consecutively isolated using BACTEC from blood samples of patients between 2008 and 2014 in Shiraz, Iran. The isolates were identified as Salmonella, based on biochemical tests embedded in the API-20E system. In order to characterize the biogroups and subspecies, biochemical testing was performed. Susceptibility testing (disc diffusion and agar dilution) and extended-spectrum β-lactamase (ESBL) detection were performed according to the clinical and laboratory standards institute (CLSI) guidelines.


RESULTS
Of the total 19 Salmonella spp. isolates recovered by the BACTEC automated system, all belonged to the Salmonella enterica subsp. houtenae. Five isolates (26.5%) were resistant to azithromycin. Six (31.5%) isolates with the disc diffusion method and five (26.3%) with the agar dilution method displayed resistance to nalidixic acid (minimum inhibitory concentration [MIC] > 32 μg/mL). All nalidixic acid-resistant isolates were also ciprofloxacin-sensitive. All isolates were ESBL-negative. Twenty-one percent of isolates were found to be resistant to chloramphenicol (MIC ≥ 32 μg/mL), and 16% were resistant to ampicillin (MIC ≥ 32 μg/mL).


CONCLUSIONS
The results indicate that multidrug-resistant (MDR) strains of Salmonella are increasing in number, and fewer antibiotics may be useful for treating S. enterica infections. Routine investigation and reporting of antibiotic MICs in patients presenting with Salmonella infections is suggested.
Professor Alborzi Clinical Microbiology Research Center, Nemazee Hospital, Shiraz University of Medical Sciences, Shiraz, IR Iran.
Mojtaba
M
Anvarinejad
Professor Alborzi Clinical Microbiology Research Center, Nemazee Hospital, Shiraz University of Medical Sciences, Shiraz, IR Iran.
Gholam Reza
GR
Pouladfar
Professor Alborzi Clinical Microbiology Research Center, Nemazee Hospital, Shiraz University of Medical Sciences, Shiraz, IR Iran.
Bahman
B
Pourabbas
Professor Alborzi Clinical Microbiology Research Center, Nemazee Hospital, Shiraz University of Medical Sciences, Shiraz, IR Iran.
Maneli
M
Amin Shahidi
Professor Alborzi Clinical Microbiology Research Center, Nemazee Hospital, Shiraz University of Medical Sciences, Shiraz, IR Iran.
Noroddin
N
Rafaatpour
Professor Alborzi Clinical Microbiology Research Center, Nemazee Hospital, Shiraz University of Medical Sciences, Shiraz, IR Iran.
Mohammad Ali
MA
Dehyadegari
Professor Alborzi Clinical Microbiology Research Center, Nemazee Hospital, Shiraz University of Medical Sciences, Shiraz, IR Iran.
Pejman
P
Abbasi
Department of Microbiology, School of Medicine, Gonabad University of Medical Sciences, Gonabad, IR Iran.
Jalal
J
Mardaneh
Antimicrobial Resistance; BACTEC Automated System; Blood; Minimum Inhibitory Concentration; Salmonella spp.