PREVALENCE AND ANTIBIOTIC RESISTANCE PATTERN OF STREPTOCOCCUS PNEUMONIAE, ISOLATED FROM INVASIVE AND NON-INVASIVE INFECTIONS IN A TERTIARY CARE HOSPITAL OF KARACHI

Fouzia Zeeshan Khan, Samina Baig, Samreen Zameer and Shaheen Sharafat. Dow University of Health Sciences, Karachi, Pakistan, Gulzar-e-Hijri, Scheme: 33, off. University Road., Karachi, Pakistan-17000. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History


826
been changed. High rates of resistance against β-lactam and Macrolide have been reported in Asian countries [10][11][12]. This situation is getting worst and adding burden on economical and medical resources. Therefore, this study was planned to determine the prevalence and antibiotic susceptibility pattern of S. pneumoniae isolated from different clinical sources during the period of 2014 to 2015 from a tertiary care hospital of Karachi.

Methodology:
This was a cross sectional study conducted in the Department of Microbiology, Dow Diagnostic Research and Reference Laboratory, Karachi, Pakistan, during the period of January 2014 to October 2015. The approval of study was taken from the institutional ethical and research committee. S. pneumoniae was isolated from clinical samples including non-invasive (sputum, ear swab, eye swab and pus swab) and invasive (blood, CSF and pleural fluid). S. pneumoniae ATCC 49619 was used as a positive control.

Inoculation of sample:
Clinical specimens were inoculated on sheep blood agar (oxoid) and chocolate agar (oxoid). They further incubated in 5% CO 2 at 37 o C for 18-24 hours.

Identification:
Isolates of S. pneumoniae were identified on the basis of α-hemolysis and inhibitory zone around optochin (05 μg) disc and Gram staining.

Statistical Analysis:
The data were analyzed using SPSS software version 20.

Results:
S. pneumoniae were isolated from the clinical samples. Out of 71 isolates, 40 were recovered from females as shown in Figure 1.
The resistance patterns of non-invasive pneumococcal infections against different antimicrobial agents are shown in Table 1. Highest resistance was observed against Clotrimoxazole, Clindamycin and Ofloxacin in children, adolescents and adults, respectively.
Among invasive pneumococcal infections, resistance was observed against Pencillin G, Clotrimoxazole and Macrolides in children, adolescents and adults, respectively as shown in Table 2. 827

Discussion:
S. pneumoniae is the leading cause of hospitalization and death of adults and children [12]. A number of significant challenges remain with regards to the diagnosis, treatment, and prevention of pneumococcal infections [6]. Treatment strategies against pneumococcal infections have been compromised by the emergence of increasing resistance of the pathogen to commonly used antibiotics [13][14][15]. This study discusses the prevalence and antibiotic susceptibility pattern of S. pneumoniae isolated from different clinical samples from a tertiary care hospital of Karachi.
Our study showed that female patients were more in number as compared to male patients suffering from pneumococcal infections, whereas, study reported male predominance [16]. Similarly, the high prevalence found in adults and in children in our study contradicted the other report [1]. Adults and children are the most vulnerable groups carrying infections due to the decreased immune profile. Pneumococci are part of normal flora of the upper respiratory tract. The organism overgrows and causes sinusitis, conjunctivitis and otitis media under favorable conditions. Pneumococcal infections are broadly divided into invasive and non-invasive infections; the former refers to infections isolated from sterile body sites. Blood borne infections occur in case of loss of integrity in the mucous membrane of the upper respiratory tract and may cause meningitis and other clinical syndromes [17].
Present study exhibited highest resistance of invasive pneumococcal infections against Pencillin G, Cotrimoxazole and Macrolides in children, adolescents and adults, respectively. Moore et al, reported Cotrimoxazole as a resistant drug in pneumococcal infections of children [18].
Several studies have reported high emergence of Penicillin and Macrolide resistance in Asian countries [19][20][21][22][23]. Antimicrobial resistance of S. pneumoniae is a global issue, more likely to be due to the over usage and improper dosage of antibiotics, over the counter sale, and malpractice of physicians. The strict implication of the drug quality and implementation of drug regulations are not easy in developing countries. Therefore, low quality of antimicrobials is increasing and equally contributing to the emergence of resistance.
Β-lactams are the most commonly used antibiotics for the treatment of pneumococcal infections. Resistance against β-lactam antibiotics has developed due to the mutations in PBP (Penicillin binding proteins) [24]. The increasing resistance of β-lactams has been resulted in the high usage of non-β-lactam antibiotics for treating pneumococcal diseases. Nowadays, Macrolides are being used as an alternative treatment of choice for pneumococcal infections. Emergence of Macrolide resistance in S. pneumoniae was first reported in the early-1990s. Indiscriminate use of semi-synthetic Macrolides including Azithromycin and Clarithromycin were mainly responsible for resistance. Macrolide resistance in S. pneumoniae is chiefly due to methylation of ribosomes by erm (B) encoded genes, erm  [25]. Resistance to Cotrimoxazole, Clindamycin and Ofloxacin was found in non-invasive pneumococcal infections of children, adolescents and adults, respectively. Cotrimoxazole resistance is also found in children suffering from upper respiratory tract infections as discussed in study [26]. Extensive use of Cotrimoxazole led to the emergence of resistance against this drug. Sulfamethoxazole-resistant isolates showed a 3 or 6 bp insertion in the Sulphonamidebinding site of folP [27]. Current study exhibited high resistance of Ofloxacin in adults but only 1.1 % of Ofloxacin-non-susceptible isolates are reported, although the rate of Fluoroquinolone resistance is low in this region [28]. Development of resistance to Fluoroquinolones is due to the mutations of gyrA and parC genes that further encode type II topoisomerase subunits also called quinolone-resistance determining regions [29]. Clindamycin resistance plus macrolide resistance is a suitable indicator for detection of the erm (B) resistance marker [24]. Clindamycin resistance was reported as 22.6% coupled with a high prevalence of Macrolide resistance. These results indicated that isolates of S. pneumoniae most probably have erm (B) resistance marker as compared with the efflux mechanism of Macrolide resistance. The high occurrence of pneumococcal antibiotic resistance genes coupled with the ease of horizontal gene transfer have enhanced global dissemination of pneumococcal multi-drug resistance, which has significant impacts on clinical practice. Treatment guidelines for pneumococcal infections must be updated according to the changes in resistance patterns [30,31].

Conclusion:
Our study exhibited increasing pattern of resistance in S. pneumoniae against commonly prescribed antibiotics. The changing trends of antibiogram of S. pneumoniae will help clinicians in selection of proper treatment. A continuous surveillance programme of antimicrobial resistance pattern in S. pneumoniae including both urban and rural areas are urgently required. Use of pneumococcal vaccination along with appropriate treatment is essential in order to decrease the morbidity and mortality.