Surveillance of extended-spectrum beta-lactamase producing bacteria in an Indian teaching hospital

To conduct surveillance of a teaching hospital in a period of 15 months, clinical samples from patients were used for the isolation of pathogenic bacteria. Bacterial isolates were isolated and identifies by standard biochemical procedures. Antibiotic sensitivity test were conducted for each isolates by Kirby-Bauer's/disc diffusion method. Extended spectrum beta lactamase [ESBL] producers were determined by double disc diffusion synergy test [DDST] and iodometric test. 2547 bacterial isolates were found belonging to 12 species namely: Escherichia coli [954], Staphylococcus aureus [661], Klebsiella pneumoniae [301], Enterococcus faecalis [175], Pseudomonas aeruginosa [121],Acinetobacter sp. [110], Citrobacter sp. [69], Klebsiella oxytoca [51], Proteus vulgaris [43], Proteus mirabilis[31], Enterobacter sp. [27], Morganella sp. [4], in descending order. The isolated bacterial strains were further tested for monitoring resistance to cefepime ceftazidime, cefotaxime, ceftriaxone [all 30 micro g/disc] and cefoperazone [75 micro g/disc] of the third generation cephalosporins [3GCs]. Numbers of resistant isolates were in descending order: Proteus vulgaris [76.7%], Morganella sp. [75.0%], Enterococcus faecalis [71.4%],Pseudomonas aeruginosa [68.6%], Proteus mirabilis [67.7%], Klebsiella oxytoca [62.6%] and Citrobactersp. [52.1%] cefepime [30 micro g/disc] and the rest other bacteria were of lesser resistant values with the least percent value, Escherichia coli [7.7%]. Similarly, Citrobacter sp. [91.3%] showed resistance to ceftazidime [30 micro g/disc] and 76.8% resistant to cefotaxime [30 micro g/disc]. Proteus mirabilis showed the highest resistance over all other isolates as 90.3% to ceftriaxone [30 micro g/disc] and 80.6% to cefoperazone [75 micro g/disc]. The resistance values to the tested 3GC antibiotics ranged from 43 to 51%. Antibiotics inhibiting beta -lactamase production were used with a blithesome control over 12 ESBL bacteria. The 3GC antibiotic group was significantly effective in controlling the GN bacterial strains in this study

A report on infection dynamics of inducible clindamycin resistance of Staphylococcus aureus isolated from a teaching hospital in India

<p><b>OBJECTIVE</b>To investigate the infection of hospital- and community-acquired "erythromycin-induced clindamycin resistant" strains or D-test positives of clinical isolates of Staphylococcus aureus (S. aureus) (with and without methicillin resistance) in a hospital.</p><p><b>METHODS</b>Strains of S. aureus isolated from clinical specimens were subjected to D-test and antibiotic profiling.</p><p><b>RESULTS</b>Of the total 278 isolates, 140 (50.35%) were D-test positives and the rest were D-test negatives. Further, of 140 (100%) positives, 87 (62.14%) and 53 (37.85%) strains were from males and females, respectively. Of 140 (100%) positives, 117 (83.57%) were methicillin resistant S. aureus and 23 (16.42%) were methicillin sensitive S. aureus; of 140 strains, 103 (73.57%) strains from persons with and 37 (26.42%) were without related infections; of 140 strains, 91 (65%) and 49 (35%) were from hospital- and community-acquired samples, respectively. In 140 strains, 118 (84.28%) with comorbidities and 22 (15.71%) without comorbidities cases were recorded; similarly, persons with prior antibiotic uses contributed 108 (77.14%) and without 32 (22.85%) positive strains. These binary data of surveillance were analyzed by a univariate analysis. It was evident that the prior antibiotic uses and comorbidities due to other ailments were the determinative factors in D-test positivity, corroborated by low P values, P=0.001 1 and 0.002 4, respectively. All isolates (278) were resistant to 17 antibiotics of nine groups, in varying degrees; the minimum of 28% resistance for vancomycin and the maximum of 97% resistance for gentamicin were recorded. Further, of 278 strains, only 42 (15.1%) strains were resistant constitutively to both antibiotics, erythromycin resistant and clindamycin resistant, while 45 (16.2%) strains were constitutively sensitive to both antibiotics (erythromycin sensitive and clindamycin sensitive). Further, of the rest 191 (68.7%) strains were with erythromycin resistant and clindamycin resistant, of which only 140 (50.35%) strains were D-test positives, while the rest 51 (18.34%) strains were D-test negatives.</p><p><b>CONCLUSIONS</b>In view of high prevalence of D-test positive S. aureus strains, and equally high prevalence of multidrug resistant strains both in community and hospital sectors, undertaking of D-test may be routinely conducted for suppurative infections.</p>