Antimicrobial Susceptibility Pattern of Some Recently Isolated Serovars of Salmonellae in Jos, Nigeria

Aim: To determine the salmonellae serovars circulating in North Central Nigeria and their treatability with commonly used antimicrobial agents.

Study Design: Investigative

Place and Duration of Study: Samples were collected and processed at the Jos University Teaching Hospital (JUTH), Plateau State, Nigeria between 2006 and 2011.

Methodology: Standard microbiological tests were used for isolation, identification and serotyping of salmonellae from 3509 blood and 5426 stool samples collected from patients attending Jos University Teaching Hospital (JUTH), Jos between 2006 and 2011. Identified serovars were subjected to antimicrobial susceptibility testing using disc diffusion method.

Results: 89 Salmonella isolates were obtained from 8935 samples. Blood and stool cultures yielded 1.4% and 0.70% salmonellae respectively. The highest number of isolates was from age group 0-9 years 30(33.7%) while patients aged 70 and above accounted for the least number of isolates 1(1.1%). Males accounted for more isolates 49(55.1%) than females 40(44.9%) (p<0.05). The 89 isolates encountered comprised 39 serovars of which 74(83.1%) were non-typhoidal. Frequently isolated serovars were S. typhimurium and S. bargny 11(12.3%) each, S. typhi 7(7.7%) and S. paratyphi B and S. saint Paul 6(6.7%) each. Rare serovars isolated included S. Lagos, S. aba, S. kisii, S. okerara and S. aminatu 1(1.1) each. All isolates were susceptible to ciprofloxacin and ceftriaxone( MIC≤ 1µg/mL) while more than 50% of the frequently isolated serovars were resistant to chloramphenicol, amoxicillin and cotrimoxazole.

Conclusions: This study reveals a high occurrence of invasive non-typhoidal, multi-drug resistant Salmonella serovars. However, susceptibility to ciprofloxacin and ceftriaxone is completely preserved and can be used for empirical treatment of salmonellosis.