Drug Resistance Patterns of Bacterial Pathogens from Adult Patients with Pneumonia in Arba Minch Hospital, South Ethiopia

Background: Community-acquired pneumonia (CAP) is associated with high mortality. Drug resistance is common in countries where the alternative treatments are limited and available drugs are misused. In resource limited countries like Ethiopia; it is wise to determine antimicrobial susceptibility pattern of common bacterial pathogens of CAP. The objective of our study was to determine antimicrobial susceptibility pattern of common bacterial pathogens of CAP among adult patients visiting Arba Minch Hospital. Methods: A cross sectional study conducted at Arba Minch Hospital, Southern Ethiopia from February to May 2013. Sputum specimens were collected; microbiological investigations and antimicrobial susceptibility testing were performed using standard procedures. Data was processed and analyzed with SPSS version16.0. Results: Out of 170 cases, only 73 (42.9%) were culture positive. Majority of tested bacterial isolates (>86%) were sensitive to Ceftriaxone and Ciprofloxacin. Most S. pneumoniae isolates (60%) were resistant to Oxacillin. Most of S. aureus and gram negative bacterial isolates were resistance to Tetracycline (100%), Penicillin (83.3%), Ampicillin (50-100%), Doxycycline (50-100%), and Trimethoprim-sulfamethoxazole (83.3-100%). Multidrug resistance (MDR) was observed to most (60.3%) bacterial isolates. Conclusion: Antimicrobial resistance including MDR was observed to a number of commonly used antibiotics, such as trimethoprimsulfamethoxazole, penicillin groups and doxycycline. Hence, periodic monitoring of drug resistant pattern is essential for better management of CAP.


Introduction
Community-acquired pneumonia (CAP) affects 3-5 adults per thousand per year with a mortality of 7-14% in hospitalized patients [1]. It is associated with high mortality. About 5.6 million cases of CAP are reported in the United States each year, with an associated mortality rate of approximately 14% [2,3]. Despite the advent of potent antibiotic over the last decades, significant mortality is still associated with CAP [4]. Increased antibiotic resistance in frequently isolated bacterial pathogens from CAP patients has complicated the selection process of antimicrobial agents [5] and the clinical presentation is usually not specific enough to make a firm etiologic diagnosis [6]. The resistant strains of bacteria can quickly multiply and spread within a community where antibiotic use is common. Consequently, antibiotic resistance often results in various societal costs, including increased drug costs, additional health-service costs (such as laboratory tests and hospitalizations)and greater drug resistance-related morbidity and mortality, and productivity losses [7]. In resource limited developing countries like Ethiopia; it is wise to determine antimicrobial susceptibility pattern of bacterial pathogens. This might help for the management of the case in case of emergency and helps for the rational utilization of antimicrobial agents.

Result
A total of 170 adult patients clinically diagnosed to have CAP in Arba Minch Hospital were selected and participated in this study ( Table 1). Of these, 95 (55.9%) were males and 75 (44.1%) were females.
Multidrug resistance was also observed to a number of antimicrobial agents (Table 3)

Discussion
The importance of knowing susceptibility patterns of bacterial isolates in patients with Community-acquired pneumonia has been identified as a key step towards limiting unnecessary antibacterial prescribing and treating patients effectively, which was the main purpose of this study.
All H. influenzae isolates tested for antimicrobial sensitivity showed low resistance (25%) to ceftriaxone, ciprofloxacin and chloramphenicol. These findings are comparable to study conducted in Nigeria (chloramphenicol 30.3% and ciprofloxacin 26.1%) [13]. In most of tested H. influenzae isolates, high resistance rate to tetracycline (100%), ampicillin (50%) and trimethoprimsulfamethoxazole (100%) were observed. These findings are similar with studies conducted in USA (47% resistance to ampicillin) [17] and Nigeria (93.7% resistance to trimethoprim-sulfamethoxazole) [13], but is not as high as that observed in other countries such as in China (>90% susceptibility to most antibiotics) [16]. The differences in antibiotic resistance patterns may be due to variations in the antibiotic prescribing habits in different geographical regions.

Conclusion
In the present study, most bacterial isolates were susceptible to ceftriaxone and ciprofloxacin. However, antimicrobial resistance including Multidrug resistance was observed to a number of commonly used antibiotics, such as trimethoprim-sulfamethoxazole, penicillin group and doxycycline. Hence, it is important to periodically monitor the antibiotic resistance patterns to aid physicians to choose empirical treatments for better management of CAP.