Muhammad Usman Arshad

Metallo--lactamase producing Enterobacter cloacae: An emerging threat in neonates

Enterobacter cloacae is not a primary human pathogen but has obtained an important role as a nosocomial pathogen. Acquiring this property of metallo-β-lactamases (MBL) producers, the pathogen becomes very virulent for the susceptible neonates and leaves little choice of antibiotics for its management. Blood samples (n=103) were collected in peadriatic blood culture bottles from suspected neonates aseptically. The samples were processed in BACTEC 9120. Antimicrobial susceptibility testing was performed using Kirby-Bauer disc diffusion method according to CLSI 2009. Carbapenems resistant E. cloacae were further analyzed for the detection of carbapenamase as per CLSI guidelines and MBL production by double disc potentiation method. Of 103 blood cultures specimens, 71 were declared positive by BACTEC 9120 and 91 isolates were recovered. Among these isolates, E. cloacae (n=12) were found to be carbapenems resistant and 10 out of these were carbapenamase and MBL producers. All MBL producing pathogens were pan-drug resistant. The spread of MBL among E. cloacae is an emerging threat particularly in hospitalized neonates. Key words: Enterobacter cloacae, metallo-β-lactamases (MBL), antimicrobial resistance.

A Novel Complementary Alternative Medicine: An In-Vitro Evaluation of Efficacy of Nigella sativa Extract as an Antibacterial Agent against Porphyromonas gingivalis

Introduction: Periodontitis is an inflammatory disease which causes progressive destruction of the periodontium resulting in pocket formation, gingival recession and tooth loss. The overwhelming cost of periodontal treatment, unpleasant side effects of antibiotics, emergence of new bacterial strains and their resistance call for an alternative treatment modality which can address all these issues. Nigella sativa is an annual herbaceous plant. It is commonly known as black seed which has been used for more than 2000 years as a natural remedy. Numerous studies have confirmed the biological functions of black seed and demonstrated its anti-inflammatory, antimicrobial, antifungal and anticancer activity. Objective: To determine the frequency of Porphyromonas gingivalis in chronic periodontitis patients and evaluate the efficacy of black seed extract against it. Methodology: Porphyromonas gingivalis was isolated from subgingival plaque samples and identified up to species level. Ethanolic extract of black seed was screened for antibacterial activity by agar well diffusion and agar dilution method. A reference strain of Porphyromonas gingivalis ATCC 33277 was used as quality control. Results: All the tested strains of Porphyromonas gingivalis were sensitive to ethanolic extract of black seed at concentrations 25, 50, 75 and 100%. The extract had an MIC range of 2-4mg/ml. Conclusion: These results indicate that ethanolic extract of black seed has potent antibacterial activity against Porphyromonas gingivalis. So black seed extract can be used in periodontal therapy as an adjuvant to scaling.

Non-O1Vibrio cholerae bacteremia in an infant, first case report from Pakistan

To the best of our knowledge, Non-O1 Vibrio cholerae (NOVC) bacteremia has never been documented in Pakistan. This case report is the first reported case of bacteremia in an infant due to NOVC in Pakistan. A neonate was admitted to a hospital with fever and no history of diarrhea. The isolate was identified biochemically and serologically and was sensitive to all the drugs tested as per CLSI 2014 guidelines.

In Vitro Antimycobacterial Activity of Pakistani Beri Honey Using BACTEC MGIT 960

Background. Tuberculosis (TB) is a chronic bacterial disease. Mycobacterium tuberculosis, being the leading member of the MTB complex, is the main cause of tuberculosis worldwide. Tuberculosis is managed with combination of drugs: streptomycin, isoniazid, rifampicin, ethambutol, and pyrazinamide. Over the recent past years resistance against first line antituberculous drugs has emerged rapidly throughout the world resulting in MDR strains. The new threat in the management of MDR-TB is the development of resistance against second line drugs: aminoglycosides, polypeptides, fluoroquinolones, and thioamides. Multidrug resistant (MDR) and extensively drug resistant TB (XDR) strains have become a major concern to control TB particularly in the developing countries. The need of the hour is to look for new modalities having antimycobacterial activity. Honey has been well known for its antibacterial activity. We intended to explore its antimycobacterial activity against MDR-TB. Objective. The objective of this study was to determine whether Pakistani Beri honey has any antimycobacterial activity. Method. The study was conducted in the Department of Microbiology, University of Health Sciences, Lahore. Clinical isolates (n = 21) of MDR-MTB were evaluated for their susceptibility to Beri honey. The isolates were provided, courtesy of Pakistan Medical Research Council. These isolates were identified by MTBc ID test (Becton & Dickinson) and further tested for their antimycobacterial activity using Beri honey. The honey was tested at the following concentrations (v/v): 1%, 2%, 3%, 4%, and 5% in MGIT 960. Growth controls were also inoculated with each isolate (growth control has no concentration of honey, only containing growth of isolate). Results. MDR-TB isolates (n = 21) were tested; 3 (14%) isolates were susceptible at 1% v/v honey, while at 2% v/v of honey 18 (86%) isolates were found to be susceptible. All the 21 isolates (n = 21) were susceptible at 3% v/v of honey. Conclusion. The present study clearly demonstrates that Pakistani Beri honey possesses significant antimycobacterial activity in vitro. The antimycobacterial activity of Pakistani Beri honey may, therefore, be exploited in an appropriate mouse model.

In-vitro efficacy of polymyxin B with rifampin, colistin and doxycycline against extensively drug resistant Acinetobacter baumannii

Acinetobacter baumannii is an opportunistic Gram negative coccobacillus that can grow easily in moist as well as dry conditions. During the last decade, A. baumannii emerged as one of the most resistant opportunistic pathogens responsible for nosocomial infections including ventilator associated pneumonia. The bug remains an important and difficult to treat pathogen whose pan-drug resistant nature has created a serious challenge. This has restricted the choice of treatment modalities. Currently, it appears as if all the available antibiotics are failing against this pathogen while single antibiotic therapy is certainly not working anymore. Thus, there is a strong need, thus, to explore new regimens to combat this resistant organism. A wide range of various combinations of drugs should therefore be tested for their synergistic activity against this pathogen. This study was aimed to find some effective combinations against extensively drug resistant (XDR) A. baumannii by combining various antibacterials. The microdilution checkerboard titration method was used for this purpose and fractional inhibitory concentrations (FICs) were calculated. In-vitro synergy was found in polymyxin B-colistin (n = 3; 15%) and polymyxin B-rifampin (n = 3; 15%) combinations. Only additive effect was noted with polymyxin B-doxycycline (n = 12; 60%), polymyxin B-rifampin (n = 11; 55%), and polymyxin B-colistin (n = 13; 65%). However, antagonism was detected in the polymyxin B-rifampin combination in one of the 20 strains evaluated for the purpose. Polymyxin B in combination with rifampin and colistin may be exploited against XDR A. baumannii. Synergy between polymyxin B and colistin have been demonstrated in only 15% of strains, this fully warrants the testing of more combinations. Key words: Acinetobacter baumannii, extensively drug resistant, fractional inhibitory concentration.