Bacteriologic profile and antibiogram of blood culture isolates from a children's hospital in Kabul

Abstract

Objective: To identify the bacterial pathogens causing paediatric septicaemia in Kabul and to determine their antibiogram to improve empirical antibiotic therapy.

Study design: Cross-sectional study.

Place and duration of study: Microbiology Laboratory of FMIC, Kabul, Afghanistan, from January 2010 to June 2012.

Methodology: Blood cultures from suspected cases of sepsis were processed in BD (Becton Dickinson, USA) for culture BACTEC™ 9240 Blood Culture System. Positive growths were examined and isolates were identified by conventional biochemical tests. Bacteria were identified to the species level using various Analytical Profile Index (API) identification strips. Antibiotic susceptibility testing was performed by modified Kirby-Bauer disk diffusion method. Drug resistant strains were studied for extended spectrum beta lactamase (ESBL) production by combination disk method and for methicillin resistant Staphylococcus aureus (MRSA) by Cefoxitin disk diffusion method.

Results: Out of a total 3360 blood cultures received from in-patients, 410 yielded monomicrobial growth; hence the frequency of positive blood culture was 12.2%. Out of a total 410 isolates, 212 (51.71%) were gram-negative bacilli and 184 (44.88%) were gram-positive cocci. In addition, 14 (3.41%) Candida species were also isolated. The frequently isolated species of gram-negative bacteria belonged to Enterobacteriaceae and included 66 Klebsiella (16.1%), 42 Enterobacter (10.2%), 35 Escherichia (E.) coli (8.5%) and 16 Serratia (3.9%) species. In addition, 21 (5.12%) Pseudomonas species were also isolated. Correspondingly, amongst gram-positive cocci, the most frequently isolated species were 108 coagulase-negative Staphylococci (26.34%) followed by 49 Staphylococcus aureus (11.95%) and 21 Streptococcus species (5.12%). Among gram-negative isolates, those that produced ESBL i.e., 110 out of 212 (51.9%) were found to be multidrug-resistant and showed high resistance to commonly used antibiotics namely Ampicillin, Gentamicin, 3rd generation Cephalosporins, Fluoroquinolones and Co-trimoxazole. Most of the isolates were susceptible to Imipenem (200/212, 94.3%), Amikacin (172/212, 81.1%) and Fosfomycin (166/212, 78.3%). Amongst gram-positive cocci, majority were resistant to Penicillin, Gentamicin, 3rd generation Cephalosporins, Fluoroquinolones and Cotrimoxazole. However, most were sensitive to Vancomycin (183/184) Pristinamycin (161/184, 87.5%) and Fosfomycin (134/184, 72.8%). All Staphylococci were resistant to Penicillin and 80/157 (51%) were MRSA.

Conclusion: Klebsiella, E. coli, Enterobacter and Staphylococci remain the principal organisms responsible for blood stream infection in a paediatrics tertiary care setting in Kabul. The most sensitive among the tested antibiotics for gram-negative organisms were Imipenem, Amikacin, and Fosfomycin and for gram-positive organisms were Vancomycin, Pristinamycin and Fosfomycin.