January 1989, Volume 39, Issue 1

Original Article

USE OF PROPHYLACTIC ANTIBIOTIC IN CLEAN SURGICAL CASES — A PROSPECT WE TRIAL OF VARIOUS REGIMENS

Syed Sultan  ( Surgical “B” Unit, DHQ Teaching Hospital and Ayub Medical College, Abbottabad. )
Rashid Ahmed  ( Surgical “B” Unit, DHQ Teaching Hospital and Ayub Medical College, Abbottabad. )
Tariq Mufti  ( Surgical “B” Unit, DHQ Teaching Hospital and Ayub Medical College, Abbottabad. )
Gul Mohammad  ( Surgical “B” Unit, DHQ Teaching Hospital and Ayub Medical College, Abbottabad. )
Mohammad Nawaz  ( Surgical “B” Unit, DHQ Teaching Hospital and Ayub Medical College, Abbottabad. )

Abstract

In a randomised controlled prospective trial, different antibiotic regimens were evaluated as prophy­laxis in wound infection following elective surgical procedures. Four hundred and four consecutive cases were divided in four groups. Two groups were allotted two different conventional postoperative antibiotic regimens while the fourth group received short term perioperative antibiotic; group one served as control. A higher frequency of postoperative wound infection was observed in the controls. Results showed reduction in gross infection in only group III where short term perioperative antibiotic was used. Com­bination of penicillin and streptomycin were not found effective, and low infection rate was observed with Cephamendole used perioperatively (JPMA 39: 9, 1989).

INTRODUCTION

Incidence of postoperative surgical wound infection is well recognised. Morbidity and mor­tality is directly related to inadequate hospital facilities, poor health standards of masses and inadequate personal hygiene. These factors make the need for routine and effective prophylactic antibiotic therapy necessary during surgery. History of antibiotic prophylaxis for wound infection was traced back to approximately fifty years1. A variety of antibiotic regimens have since been used routinely in the postoperative period. 2 In the early seventies prophylactic use of antibiotics for clean surgical procedures was considered unnecessary. However, in the recent past the use of routine antibiotic prophylaxis for all sorts of surgical wounds has been considered an essential step in the reduction of postoperative wound infections. 3-5 A trial was therefore conducted at the DHQ Hospital, Abbottabad to compare various conventional antibiotic regimens as well as a short term perioperative prophylaxis in different elective surgical procedures. The effect of prophylactic use of antibiotics, nature of infecting organisms and their sensitivity and duration of hospital stay were also determined.

MATERIAL AND METHODS

Four hundred and four cases admitted in the surgical unit of DHQ Hospital, Abbottabad between October 1984 to October 1986, were included in the study. All operations were elective and fell in the category of “clean or “ clean-contaminated cases according to clinical categori­sation of surgical procedures2. Patients were divided in four groups. Three were allocated different prophylactic anti­biotics regimens and the fourth group used as control where no prophylaxis was used (Table 1).

Selection of conventional regimens in two groups was based on the survey of prescribing regi­mens in various centres of the country. Choice of Cafamendal (a second generation cephalosporin) in group four was made on existing evidence of successful use of cephalosporins in similar trials2-6. Patients were randomly selected (for each group of pathology) in chronological order of hospitalization. Acceptable similarities in the sizes of different groups and pathologies were ensured by retrospective data analysis from time to time. Doses of antibiotics used were calculated according to age and weight of the patient. All wounds were tightly sealed at the completion of operation. Wounds were inspected on 4th posto­perative day and then followed up accordingly. Infection was categorised as below:—
1)  Mild infection: Evidence of celu­litis, oedema or stitch abcess.
2)  Gross infection: Subfacial or deeper collection of pus.
Cases with gross infection had culturel sensitivity tests for the pus. Appropriate antibio­tics were started only if infection did not settle after sufficient period of simple drainage. Mean hospital stay for each group was calculated.

RESULTS

All the cases were divided into 4 groups. Groups II, III and IV were treated, while group I served as control. Their distribution according to pathological categories is shown in Table II.

The frequency of infection in treated groups was compared with the control group (Table III).

The frequency of mild infection was almost similar but gross infection was significantly more in group III. Gross infection (pus formation) in treated and non-treated groups was similar in both the sexes. Forty two patients developed gross infection and the discharging pus was sent for culture and sensitivity. Growth pattern of organisms is shown in Table IV.

Staph aureus was the commonest infecting organism followed by E. Coil which was equally frequent in Group I and II but not in Group III. Negative culture were presumed to be due to infection with bacteroides. Culture facilities for anaerobes not being available, further study was not possible. Average posto­perative hospital stay was 17.7 days and 11.1 days for infected and non-infected cases, respec­tively.

DISCUSSION

Place of antibiotic prophylaxis to mini-mise postoperative wound infection in elective surgical cases has been widely discussed1,6,9. Although the efficacy of the prophylaxis is admitted by many yet there is no consensus on the selection of regimens. Recently, several workers have shown the superiority of short term perio­perative systemic antibiotic prophylaxis over con­ventional prolonged medication used postopera­tively. 6,7,10,11 The findings of the present trials showed that higher frequency of postoperative wound infection in group I is in accordance with other reported series11-13. Incidence as high as 50% has been reported when no antibiotic was used. 14 In group II where combination therapy of Penicfflin and Streptomycin was used postopera­tively, the results were not different from those of controls. Although penicillin prophylaxis was effective in cases of thoracic surgery1, in this study it was not found effective, by others possibly due to infection by resistant organisms like staph aureus or E. Coli for which broader spectrum antibiotics are needed1-3. Poor results of Group IV in the present study are rather discouraging because arninogi­ycosides were found effective in prophylaxis of wound infection in many similar trials15,16 resulting in the reduction of infection rate by 1/3 with these drugs. It is speculated that failure of Aminogly­coside group of drugs in this trial might be due to factors like local resistance pattern against common hospital bacteria and ineffectiveness of the drug against resistant bacteria (Bacteroides), or due to excessive use of these antibiotics in our hospitals producing resistant bacterial strains. Very low rate of infection obtained after perioperative short term prophylactic use of Cephamendol is in accordance with other trials2,3. Newly introduced second or third generation of cephalosporins have additional advantages of having wider range of aerobic and anaerobic anti­microbial activity with very low toxicity and quicker achievement. All these factors eventually lead to better economical implications on the patients.

ACKNOWLEDGEMENT

Authors owe their gratitude to all the staff of Surgical ‘B’ Unit, DHQ Teaching Hospital, Abbottabad for their untiring efforts in conduct­ing this trial, Mr. Sadat Khan for typing the article and the staff of PMRC for their guidance and analysis of data.

REFERENCES

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