Prevalence, Profile and Antibiotic Susceptibility Pattern of Bacterial Isolates from Blood

MATERIALS AND METHODS

A total of 448 blood samples from patients (270 male, 153 female and 25 children) were collected from hospitals Out of these blood samples, 405 (92%) were aerobically and 43 (8%) anaerobic cultured. In aerobic culture, for adult 10 mL and for children 2-5 mL of blood were inoculated in 50 mL of Brain Heart Infusion broth. The bottles were vented by inserting a sterile cotton-wool plugged needle. For anaerobic blood culture, Hartley’s Digest broth were used. These bottles were incubated at 37°C for 24 h. The inoculated broth medium (from day 2) was then sub-cultured every day on blood agar and MacConkey’s agar subsequently for 3 days and incubated for another 24 h.

Identification of organism was based on gram reactions, morphology and biochemical characteristics (Forbes et al., 1988).

Table 1:	Antibiotics disc use in study

Isolates were tested for antimicrobial susceptibility by Bauer et al. (1966) disc diffusion technique on Muller Hinton agar using the readymade antibiotics discs (Table 1).

RESULTS AND DISCUSSION

A total of 448 blood samples (405 aerobically and 43 aerobically) were cultured, out of them, 111 (27%) pathogens from aerobic and 6 (5%) pathogens from anaerobic culture were isolated and identified. In aerobic culture, Staphylococcus aureus 71 (64.54%) was the most prominent pathogen followed by Listeria monocytogenes 17(15.45%), Diplococcus sp. 7(6.36%), Salmonella typhi 6(5.45%), Streptococci sp. 4(3.63%), Klebsiella pneumoniae 3(2.72%) and one each strain of Compylobacter sp., E. coli and Haemophilus influenzae were isolated. In anaerobic culture 6 samples were positive for Clostridium perfringens (Fig. 1). The frequency of bacteraemia was 53% in male, 35% in female and 12% in children.

The antibiogram pattern of S. aureus showed high resistance to cefotaxime (96%), cefadroxil (93%), cefaclor (95%) and ceftazidime (93.10%) and high sensitivity to meropenem (70%), linezolid (74.8%) while Diplococci sp. showed high resistance to cefuroxime (91.42%) and ceftazidime (91.50%) and sensitivity to amikacin (100%), linzolid (70%) and meropenem (71.43%). The Listeria monocytogenes showed high resistance against cefuroxime (95%) and ceftazidime (93.63%) and high sensitivity to meropenem (100%), linezolid (85.72%) and amikacin (87.5%).

The blood isolate, Salmonella typhi was highly resistant to cefotaxime (91.10%) and ceftazidime (97.5%) and sensitive to meropenem (83.34%), linezolid (74.9%) and amikacin (77.15%), while Streptococci sp. was resistant to cefotaxime, cefuroxime, ciprofloxacin and pefloxacin (100% each) and sensitive to amikacin, meropenem and linzolid (100% each). The Klebsiella pneumoniae showing highest (100%) resistance to cefaclor, cefuroxime, ceftazidime and ceftriazone.

In present study, the single isolate Compylobacter showed 100% resistance to cefotaxime, cefadroxil, cefaclor, cefuroxime, ceftazidime, ceftriazone, norfloxacin, ofloxacin, pefloxacin, cefazolin and 100% sensitivity to meropenem, amikacin, linzolid and ciprofloxacin, while the single isolate E. coli showed resistance to cefotaxime, cefadroxil, meropenem, cefaclor, cefuroxime, ceftazidime, amikacin, ciprofloxacin, ceftriazone, norfloxacin, cefazolin and sensitive to linzolid, ofloxacin and pefloxacin.

Table 2:	Antibiotic resistance pattern (%) of various pathogens isolated from blood
1 = Cefotaxime, 2 = Cefadroxil, 3 = Meropenem, 4 = Linezolid, 5 = Cefaclor, 6 = Cefuroxime, 7 = Ceftazidime, 8 = Amikacin, 9 = Ciprofloxacin, 10 = Ceftriazone, 11= Norfloxacin, 12 = Ofloxacin, 13 = Pefloxacin, 14 = Cefazolin

Fig. 1:	Frequency of bacterial blood pathogens

Haemophilus influenzae showed high resistance to cefotaxime, cefadroxil, cefaclor, cefuroxime, ceftazidime, norfloxacin, ofloxacin, pefloxacin, cefazolin and sensitivity to meropenem, linzolid, amikacin, ciprofloxacin and ceftriazone. In anaerobically isolated Clostridium perfringens was highly resistance to cefotaxime and sensitivity to norfloxacin (Table 2).

All the pathogens isolated from blood showed high resistance to cefuroxime (96%), ceftazidime (95%), cefotaxime (91%) and highly sensitivity to meropenem (74%), linezolid (83%) and amikacin (77%) (Fig. 2).

Meremikmu et al. (2005) also recorded the prominent presence of S. aureus (65%) in bacteraemia. The frequency of occurrence of Streptococci sp. in blood was 3.63%, which was similarly reported by Sobhani et al. (2004). The frequency of occurrence of Diplococci sp. (6.36%), Salmonella typhi (5.45%), Streptococci sp. (3.63%) and Klebsiella pneumoniae (2.72%) in present study was similarly reported by Gholam and Kashanian (2005). Rosemarie et al. (1994) also reported the presence of Haemophilus influenzae in blood culture.

Fig. 2:	The antibiotics resistance pattern of the bacterial pathogens isolated from blood

Sobhani et al. (2004), Zakaria El-Astal (2004) and Gholam and Kashanian (2005) also reported the presence of highly sensitive blood bacterial pathogens to amikacin and ciprofloxacin and Huang et al. (2002) reported highly resistance pathogens to ceftazidime.

The present study showed the increasing antibiotic resistance against the common bacterial isolates. Resistant bacteria could be mutant form of wild bacteria due to over-use or misuse of broad-spectrum antibiotics.

Ideally blood culture and antibiotic susceptibility should be performed for the proper management of microbial infections. It is not possible to delay initiation of treatment until laboratory reports are available. In such instances and without culture facilities, knowledge of local antimicrobial resistance pattern from accurate bacteriological records of culture reports may provide guidance towards an empirical therapy before sensitivity pattern are available.

In present study all the pathogens isolated from blood showed high resistance to cefuroxime, ceftazidime, cefotaxime and highly sensitivity to meropenem, linzolid and amikacin. The study indicated the common antibiotics pattern in this region, which helps in prescribing the proper antibiotics against bacteraemia and avoid the misuse or overuse of unwanted or resistant antibiotics for proper treatment to patient. The increasing resistance of organisms indicates that periodic monitoring and possibly modification of empirical therapy are required.