(12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT) (19) World Intellectual Property Organization International Bureau (10) International Publication Number (43) International Publication Date WO 2013/014497 Al 31 January 2013 (31.01.2013) P O P C T (51) International Patent Classification: (81) Designated States (unless otherwise indicated, for every A61K 31/4188 (2006.01) A61K 31/431 (2006.01) kind of national protection available): AE, AG, AL, AM, A61K 31/424 (2006.01) A61K 45/06 (2006.01) AO, AT, AU, AZ, BA, BB, BG, BH, BR, BW, BY, BZ, A61K 31/43 (2006.01) A61P 31/04 (2006.01) CA, CH, CL, CN, CO, CR, CU, CZ, DE, DK, DM, DO, DZ, EC, EE, EG, ES, FI, GB, GD, GE, GH, GM, GT, HN, (21) Number: International Application HR, HU, ID, IL, IN, IS, JP, KE, KG, KM, KN, KP, KR, PCT/IB201 1/054352 KZ, LA, LC, LK, LR, LS, LT, LU, LY, MA, MD, ME, (22) International Filing Date: MG, MK, MN, MW, MX, MY, MZ, NA, NG, NI, NO, NZ, 4 October 201 1 (04. 10.201 1) OM, PE, PG, PH, PL, PT, QA, RO, RS, RU, RW, SC, SD, SE, SG, SK, SL, SM, ST, SV, SY, TH, TJ, TM, TN, TR, (25) Filing Language: English TT, TZ, UA, UG, US, UZ, VC, VN, ZA, ZM, ZW. (26) Publication Language: glish ( ) Designated States (unless otherwise indicated, for every (30) Priority Data: kind of regional protection available): ARIPO (BW, GH, 2125/MUM/201 1 26 July 201 1 (26.07.201 1) IN GM, KE, LR, LS, MW, MZ, NA, RW, SD, SL, SZ, TZ, 2157/MUM/201 1 29 July 201 1 (29.07.201 1) IN UG, ZM, ZW), Eurasian (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), European (AL, AT, BE, BG, CH, CY, CZ, DE, (71) Applicant (for all designated States except US): WOCK- DK, EE, ES, FI, FR, GB, GR, HR, HU, IE, IS, IT, LT, LU, HARDT LIMITED [IN/IN]; D-4, MIDC Area, Chi- LV, MC, MK, MT, NL, NO, PL, PT, RO, RS, SE, SI, SK, kalthana, Aurangabad 431210 (IN). SM, TR), OAPI (BF, BJ, CF, CG, CI, CM, GA, GN, GQ, GW, ML, MR, NE, SN, TD, TG). (72) Inventors; and (75) Inventors/Applicants (for US only): BHAGWAT, Sachin Published: Subhash [IN/IN]; Row House No.C-2, "Nilgiris", Khiv- — with international search report (Art. 21(3)) ansara Park(E), Behind Ramayana, Cultural Hall, Ulkanagari, Aurangabad 431210 (IN). PATEL, Mahesh Vithalbhai [IN/IN]; Plot No. 157, Opposite Saint Meera School, N-3, CIDCO, Aurangabad 43 1003 (IN). (54) Title: PHARMACEUTICAL COMPOSITIONS COMPRISING BETA-LACTAM ANTIBIOTIC, SULBACTAM AND BETA- LACTAMASE INHIBITOR (57) Abstract: Pharmaceutical compositions and methods for treating or preventing bacterial infections are disclosed. The pharma ceutical compositions typically comprise pharmaceutically effective amount of: (a) at least one beta-lactam antibiotic or a pharma ceutically acceptable salt thereof, (b) sulbactam or a pharmaceutically acceptable salt thereof, and (c) at least one beta-lactamase in - hibitor or a pharmaceutically acceptable salt thereof, with the provision that the beta-lactamase inhibitor is not sulbactam. PHARMACEUTICAL COMPOSITIONS COMPRISING BETA- LACTAM ANTIBIOTIC, SULBACTAM AND BETA-LACTAMASE INHIBITOR RELATED PATENT APPLICATIONS This application claims the benefit of Indian Patent Application Nos. 2125/MUM/2011 filed on July 26, 2011, and 2157/MUM/2011 filed on July 29, 2011, the disclosures of which are incorporated herein by reference in their entirety as if fully rewritten herein. All references including patents, patent applications, and literature cited in the specification are expressly incorporated herein by reference in their entirety. FIELD OF THE INVENTION The invention relates to antibacterial compositions and methods for preventing or treating bacterial infections. BACKGROUND OF THE INVENTION Resistance to beta-lactam antibiotics is wide spread and a key concern. One of the mechanism bacteria have developed against beta-lactam antibiotics is production of several beta-lactamase enzymes, which deactivate the beta-lactam antibiotic. In general, a typical beta-lactam antibiotic alone may not be effective in treating infections caused by such beta- lactamase producing bacteria. One alternative to treating infections caused by bacteria producing beta-lactamase enzymes is by co-administration of a beta-lactamase inhibitor with the beta-lactam antibiotic. The beta-lactamase inhibitor prevents deactivation of a beta-lactam antibiotic, typically by binding with the beta-lactamase enzyme. However, even the combination therapy is also proving ineffective in treating infections caused by newer ESBL strains. Drawz et al. (Clinical Microbiology Reviews, 2010, 23(1), pages 160-201) have reviewed developments in the area of beta-lactamase inhibition and inhibitors. Drawz et al. summarize various beta-lactamase inhibitors developed to overcome bacterial resistance. Gold et al. (The New England Journal of Medicine, 1996, 335(19), pages 1445-1453) have also reviewed the subject of antimicrobial drug resistance. The widespread emergence of newer strains that do not respond to even the combination therapies, is becoming a major concern. It is estimated that, internationally the prevalence of ESBL in Klebsiella and E. coli is in the range of 30-50% depending upon the geographical location. For ESBLs, carbapenem therapy is the most widely used in the clinical settings today. Presently, all strains identified as inhibitor resistant ESBLs are treated only by carbapenems. However, some of the emerging ESBLs (e.g. those containing metallo- betalactamases, KPCs and Class D ESBLs) appear to exhibit higher degree of resistance to even carbapenems. Thus, there is a need to develop new ways to treat infections that are becoming resistant to known therapies and methods. SUMMARY OF THE INVENTION Accordingly, there are provided pharmaceutical compositions and methods for treating or preventing bacterial infections. In one general aspect, there are provided pharmaceutical compositions comprising pharmaceutically effective amount of: (a) at least one beta-lactam antibiotic or a pharmaceutically acceptable salt thereof, (b) sulbactam or a pharmaceutically acceptable salt thereof, and (c) at least one beta-lactamase inhibitor or a pharmaceutically acceptable salt thereof, with the provision that the beta-lactamase inhibitor is not sulbactam. In another general aspect, there is provided a method for preventing or treating a bacterial infection in a subject, said method comprising administering to said subject a pharmaceutically effective amount of a pharmaceutical composition comprising pharmaceutically effective amount of: (a) at least one beta-lactam antibiotic or a pharmaceutically acceptable salt thereof, (b) sulbactam or a pharmaceutically acceptable salt thereof, and (c) at least one beta-lactamase inhibitor or a pharmaceutically acceptable salt thereof, with the provision that the beta-lactamase inhibitor is not sulbactam. In another general aspect, there is provided a method for preventing or treating a bacterial infection in a subject, said infection being caused by bacteria producing one or more beta-lactamase enzymes, wherein the method comprises administering to said subject a pharmaceutically effective amount of a pharmaceutical composition comprising a pharmaceutically effective amount of: (a) at least one beta-lactam antibiotic or a pharmaceutically acceptable salt thereof, (b) sulbactam or a pharmaceutically acceptable salt thereof, and (c) at least one beta-lactamase inhibitor or a pharmaceutically acceptable salt thereof, with the provision that the beta-lactamase inhibitor is not sulbactam. In another general aspect, there is provided a method for preventing or treating a bacterial infection in a subject, said method comprising administering to said subject a pharmaceutically effective amount of: (a) at least one beta-lactam antibiotic or a pharmaceutically acceptable salt thereof, (b) sulbactam or a pharmaceutically acceptable salt thereof, and (c) at least one beta-lactamase inhibitor or a pharmaceutically acceptable salt thereof, with the provision that the beta-lactamase inhibitor is not sulbactam. In another general aspect, there is provided a method for preventing or treating a bacterial infection in a subject, said infection being caused by bacteria producing one or more beta-lactamase enzymes, said method comprising administering to said subject a pharmaceutically effective amount of: (a) at least one beta-lactam antibiotic or a pharmaceutically acceptable salt thereof, (b) sulbactam or a pharmaceutically acceptable salt thereof, and (c) at least one beta-lactamase inhibitor or a pharmaceutically acceptable salt thereof, with the provision that the beta-lactamase inhibitor is not sulbactam. In another general aspect, there is provided a method for increasing antibiotic effectiveness of a beta-lactam antibiotic in a subject, said method comprising co administering said beta-lactam antibiotic with a pharmaceutically effective amount of: (a) sulbactam or a pharmaceutically acceptable salt thereof, and (b) at least one beta-lactamase inhibitor or a pharmaceutically acceptable salt thereof, with the provision that the beta- lactamase inhibitor is not sulbactam. The details of one or more embodiments of the invention are set forth in the description below. Other features, objects and advantages of the invention will be apparent from the following description including claims. DETAILED DESCRIPTION OF THE INVENTION Reference will now be made to the exemplary embodiments, and specific language will be used herein to describe the same. It should nevertheless be understood that no limitation of the scope of the invention is thereby intended. Alterations